WO2024090368A1 - Medical shaft and method for producing medical shaft - Google Patents

Medical shaft and method for producing medical shaft Download PDF

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Publication number
WO2024090368A1
WO2024090368A1 PCT/JP2023/038138 JP2023038138W WO2024090368A1 WO 2024090368 A1 WO2024090368 A1 WO 2024090368A1 JP 2023038138 W JP2023038138 W JP 2023038138W WO 2024090368 A1 WO2024090368 A1 WO 2024090368A1
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WO
WIPO (PCT)
Prior art keywords
heat shrink
shrink tube
small diameter
large diameter
shaft body
Prior art date
Application number
PCT/JP2023/038138
Other languages
French (fr)
Japanese (ja)
Inventor
健 後藤
浩二 亀岡
Original Assignee
ニプロ株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from JP2023016631A external-priority patent/JP2024062327A/en
Application filed by ニプロ株式会社 filed Critical ニプロ株式会社
Publication of WO2024090368A1 publication Critical patent/WO2024090368A1/en

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    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B18/00—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
    • A61B18/04—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by heating
    • A61B18/12—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by heating by passing a current through the tissue to be heated, e.g. high-frequency current
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M25/00—Catheters; Hollow probes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C63/00—Lining or sheathing, i.e. applying preformed layers or sheathings of plastics; Apparatus therefor
    • B29C63/38—Lining or sheathing, i.e. applying preformed layers or sheathings of plastics; Apparatus therefor by liberation of internal stresses
    • B29C63/42—Lining or sheathing, i.e. applying preformed layers or sheathings of plastics; Apparatus therefor by liberation of internal stresses using tubular layers or sheathings

Definitions

  • the present invention relates to a medical shaft that is used to perform treatment inside a patient's body by operating it from outside the body, and a method for manufacturing the medical shaft.
  • various longitudinal medical shafts are used to operate from outside the patient's body to perform treatment inside the patient's body.
  • a tubular medical device punctcture rod
  • a therapeutic catheter is known.
  • such medical shafts may have a resin layer covering the outer surface of the shaft body for some purpose, such as protecting biological tissue, preventing energy loss, and ensuring durability.
  • medical shafts are sometimes inserted into a specific location inside the body through a dilator, sheath, catheter, etc., and are required to be stably held in place by the resin layer coating, without peeling off or shifting, even when in sliding contact with the dilator, etc.
  • the inventor therefore considered fitting a heat shrink tube onto the outer circumferential surface of the shaft body to fix the resin layer in position relative to the shaft body.
  • the problem to be solved by this invention is to provide a medical shaft with a shaft body whose outer diameter varies along its length, and which has a novel structure that allows a plastic tube that covers the area of the shaft body from the small diameter section to the large diameter section to be attached in a fixed position over the entire length of the shaft body while minimizing problems caused by the large diameter.
  • the present invention also aims to provide a new method for manufacturing medical shafts, which is targeted at medical shafts having a shaft body whose outer diameter dimensions vary along the length, and which allows a resin tube that covers the area of the shaft body from the small diameter portion to the large diameter portion to be attached in a fixed position over the entire length of the shaft body while minimizing problems caused by increasing the diameter.
  • the first aspect is a medical shaft that is inserted into the body of an animal during treatment, and the shaft body has a small diameter portion and a large diameter portion with different outer diameter dimensions in the length direction, and a transition portion where the outer diameter dimension changes is provided between the small diameter portion and the large diameter portion, while the shaft body is continuously covered in the length direction with a resin tube in the area from the small diameter portion through the transition portion to the large diameter portion, and the resin tube is a joint structure in which a small diameter side heat shrink tube covering the small diameter portion and a large diameter side heat shrink tube covering the large diameter portion are joined, and a joint portion that is provided in the arrangement area of the heat shrink tube with the smaller thickness between the small diameter side heat shrink tube and the large diameter side heat shrink tube and has a thickness dimension larger than that of the heat shrink tube with the smaller thickness is positioned on the small diameter portion side where the transition portion is located, rather than the end of the large diameter portion of the shaft body.
  • the resin tube covering the shaft body having a small diameter portion and a large diameter portion is composed of a small diameter side heat shrink tube that covers the small diameter portion of the shaft body and a large diameter side heat shrink tube that covers the large diameter portion of the shaft body.
  • the resin tube is a joint structure between the small diameter heat shrink tube and the large diameter heat shrink tube
  • the joint between the small diameter heat shrink tube and the large diameter heat shrink tube is thicker than the heat shrink tube with the smaller thickness dimension, but the thick joint is located closer to the small diameter portion where the transition portion is located than the end of the large diameter portion of the shaft body.
  • the thick joint is located on the small diameter portion side of the shaft body that is smaller in diameter than the large diameter portion, so that the increase in diameter of the medical shaft due to the thick joint is less likely to be a problem.
  • the second aspect is the medical shaft described in the first aspect, in which the transition portion in the shaft body has a tapered portion in which the outer diameter dimension changes in the length direction between the small diameter portion and the large diameter portion, and the joint portion in the resin tube is positioned in a portion that covers the tapered portion.
  • a tapered portion is provided between the small diameter portion and the large diameter portion, so that the change in the outer diameter dimension between the small diameter portion and the large diameter portion is relatively gradual, and even when the shaft body is covered with a resin tube, the change in the outer diameter dimension of the resin tube at the portion covering the tapered portion is relatively gradual, and local thinning of the resin tube is easily avoided.
  • the third aspect is the medical shaft described in the first aspect, in which the transition portion in the shaft body has a stepped portion where the outer diameter dimension changes in a stepped manner between the small diameter portion and the large diameter portion, and the joint portion in the resin tube is positioned at a portion that covers the end portion of the small diameter portion in the shaft body on the stepped portion side.
  • the joint in the resin tube is provided at the portion covering the end of the small diameter portion on the step-like portion side, so that the thickness of the resin tube at this portion is increased, and the step-like change in the outer diameter can be reduced or eliminated by the thick-walled resin tube.
  • the fourth aspect is a medical shaft that is inserted into the body of an animal during treatment, the shaft body having a small diameter portion and a large diameter portion with different outer diameter dimensions in the length direction, a transition portion where the outer diameter dimension changes is provided between the small diameter portion and the large diameter portion, the shaft body is covered with a resin tube continuously in the length direction in the region from the small diameter portion through the transition portion to the large diameter portion, and the resin tube is a joint structure in which a small diameter side heat shrink tube covering the small diameter portion and a large diameter side heat shrink tube covering the large diameter portion are joined, and the small diameter side heat shrink tube and the large diameter side heat shrink tube are overlapped and joined to each other at a position closer to the small diameter portion side where the transition portion is located than the end of the large diameter portion of the shaft body.
  • the small diameter heat shrink tube can be fitted to the small diameter portion of the shaft body while the large diameter heat shrink tube can be fitted to the large diameter portion of the shaft body, and the plastic tube is attached in a state where it is aligned with the shaft body over its entire length.
  • the joint which becomes thicker when the small diameter heat shrink tube and the large diameter heat shrink tube are joined together in an overlapping state, is located on the small diameter side where the transition is located, rather than on the end of the large diameter part of the shaft body, so the increase in diameter of the medical shaft caused by the thickening of the joint is less likely to be a problem.
  • the fifth aspect is the medical shaft described in the fourth aspect, in which the transition section in the shaft body has a tapered section in which the outer diameter dimension changes in the longitudinal direction between the small diameter section and the large diameter section, and the small diameter side heat shrink tube and the large diameter side heat shrink tube are overlapped and joined to each other at a portion of the shaft body that covers the tapered section.
  • the change in the outer diameter of the resin tube at the portion covering the tapered portion is relatively gradual, and excessive enlargement of the diameter at the joint position (the position where the joint is formed) between the small diameter side heat shrink tube and the large diameter side heat shrink tube can be suppressed.
  • the sixth aspect is a medical shaft as described in the fourth aspect, in which the transition portion in the shaft body has a stepped portion where the outer diameter dimension changes in a stepped manner between the small diameter portion and the large diameter portion, and the small diameter side heat shrink tube and the large diameter side heat shrink tube are overlapped and joined to each other at a portion covering the end of the small diameter portion of the shaft body on the stepped portion side.
  • the small diameter heat shrink tube and the large diameter heat shrink tube can be connected on the outer circumferential surface of the resin tube in a curved shape that is connected relatively gently in the length direction, eliminating abrupt changes in outer diameter in the stepped portion of the shaft body.
  • the seventh aspect is a medical shaft according to the third or sixth aspect, in which the outer circumferential corner of the end of the large diameter portion of the shaft body on the stepped portion side is chamfered.
  • the outer corners of the end of the large diameter portion on the stepped portion side are chamfered, so that the thickness dimension of the portion of the plastic tube that covers the outer corners can be easily and stably ensured, and exterior processing of the plastic tube can also be easily performed.
  • the eighth aspect is a medical shaft according to the third or sixth aspect, in which an intermediate ring having an outer diameter smaller than that of the large diameter portion is attached in an externally inserted state to the end of the small diameter portion of the shaft body on the stepped portion side, and the shaft body including the intermediate ring is covered with the resin tube.
  • the provision of an intermediate ring allows the change in outer diameter dimension in the small diameter portion and the large diameter portion to be gradual, dispersing the size of the step and making it substantially smaller. Therefore, even in the resin tube that covers the area between the small diameter portion and the large diameter portion, a large change in outer diameter dimension at once is avoided. Therefore, even if the difference in outer diameter dimension between the small diameter portion and the large diameter portion is relatively large, for example, by providing a resin tube that spans between the small diameter portion and the large diameter portion in the length direction across the intermediate ring, the small diameter side heat shrink tube and the large diameter side heat shrink tube can be connected with an outer circumferential surface that is relatively gently inclined.
  • the ninth aspect is a medical shaft according to any one of the first to eighth aspects, in which the resin tube is fixed to the shaft body in an overlapping state without using adhesive.
  • the plastic tube is fitted and fixed to the shaft body without the use of adhesives, making it possible to effectively position the plastic tube relative to the shaft body while avoiding the use of adhesives that can have adverse effects on biological tissue.
  • the tenth aspect is a medical shaft according to any one of the first to ninth aspects, in which the shaft body is made of metal.
  • the shaft body is covered with a resin tube, and the flexible resin tube prevents the hard metal shaft body from coming into direct contact with biological tissue, a dilator, etc.
  • the shaft body is made of metal, electricity and heat can be easily transferred from the base end to the tip end of the shaft body, and in such cases, for example, an electrical or thermal insulating layer can be formed on the surface of the shaft body using the resin tube.
  • the eleventh aspect is the medical shaft described in the tenth aspect, in which the surface of the shaft body is roughened.
  • the surface of the metal shaft body is roughened, making it easier to position the plastic tube in the axial direction relative to the shaft body and preventing the plastic tube from shifting.
  • the twelfth aspect is a medical shaft according to the second or fifth aspect, in which the thickness dimension of the resin tube is within the range of 0.03 to 0.50 mm at the portion covering the small diameter portion and the large diameter portion of the shaft body, and the maximum thickness dimension at the joint covering the tapered portion is 1.00 mm or less.
  • a medical shaft constructed according to this embodiment can effectively achieve the various desired properties, such as cushioning, insulation, and durability, achieved by covering the shaft body with a resin tube, while preventing excessive increase in diameter.
  • the thirteenth aspect is a medical shaft according to any one of the first to twelfth aspects, in which the difference in radial dimension between the small diameter portion and the large diameter portion of the shaft body is within the range of 0.1 to 0.8 mm.
  • the difference in radius between the small diameter portion and the large diameter portion of the shaft body is so large that it is difficult to cover them with a single tube, and the difference in radius between the small diameter portion and the large diameter portion is suppressed to a degree that can prevent the joint from becoming excessively thick or the shape of the joint from becoming distorted. Therefore, by using a resin tube that serves as a joint structure between a small diameter side heat shrink tube and a large diameter side heat shrink tube, the shaft body can be effectively covered by the resin tube.
  • the fourteenth aspect is a medical shaft according to any one of the first to thirteenth aspects, in which the small diameter side heat shrink tube and the large diameter side heat shrink tube are fused together and integrated at the joint of the resin tube.
  • the small diameter heat shrink tube and the large diameter heat shrink tube are fused and integrated at the joint, so that the small diameter heat shrink tube and the large diameter heat shrink tube are unlikely to separate even if concentrated stress occurs at the joint.
  • concentrated tensile stress is likely to occur at the joint covering the change section, but even when such concentrated tensile stress acts, it is possible to prevent the small diameter heat shrink tube and the large diameter heat shrink tube from separating.
  • the fifteenth aspect is a medical shaft according to any one of the first to fourteenth aspects, in which the small diameter side heat shrink tube and the large diameter side heat shrink tube are made of the same material.
  • the small diameter heat shrink tube and the large diameter heat shrink tube can be easily fused together at the joint, making it easier to obtain high joint strength at the joint. Also, compared to when the small diameter heat shrink tube and the large diameter heat shrink tube are made of different materials, it is easier to achieve the desired performance over the entire length of the resin tube.
  • the sixteenth aspect is a method for manufacturing a medical shaft that is inserted into the body of an animal during treatment, comprising the steps of: preparing a shaft body having a small diameter portion and a large diameter portion with different outer diameter dimensions in the length direction, and having a transition portion between the small diameter portion and the large diameter portion, where the outer diameter dimension changes; extrapolating a small diameter side heat shrink tube to the small diameter portion of the shaft body, and extrapolating a large diameter side heat shrink tube to the large diameter portion of the shaft body, and extending the large diameter side heat shrink tube from the large diameter portion of the shaft body toward the transition portion, and attaching the small diameter side heat shrink tube to the small diameter side heat shrink tube on the transition portion side of the large diameter portion of the shaft body;
  • the method includes a step of placing the small diameter heat shrink tube in a burlap manner, a step of covering the outer periphery of the overlapping portion of the small diameter heat shrink tube and the large diameter heat shrink tube that are fitted onto the shaft body with a molding heat shrink tube,
  • the small diameter heat shrink tube and the large diameter heat shrink tube are placed on the shaft body in a state where they overlap on the transition portion side of the large diameter portion, and are thermally shrunk by a heat treatment. In this way, both the small diameter portion and the large diameter portion of the shaft body are covered with the resin tube without any gaps and without becoming excessively thick.
  • the overlapping portion of the small diameter heat shrink tube and the large diameter heat shrink tube is heated together with the molding heat shrink tube while covered with the molding heat shrink tube, and the shrunk molding heat shrink tube adheres closely to the overlapping portion of the small diameter heat shrink tube and the large diameter heat shrink tube.
  • the outer periphery of the overlapping portion of the small diameter heat shrink tube and the large diameter heat shrink tube is shaped by the molding heat shrink tube, making it less likely to become distorted.
  • the seventeenth aspect is the method for manufacturing a medical shaft described in the sixteenth aspect, in which the transition portion in the shaft body has a tapered portion in which the outer diameter dimension changes in the length direction between the small diameter portion and the large diameter portion, and during the heat treatment, the small diameter side heat shrink tube and the large diameter side heat shrink tube are arranged so as to overlap each other at the tapered portion of the shaft body.
  • the small diameter side heat shrink tube and the large diameter side heat shrink tube are arranged so that they overlap each other at the tapered portion, and by thermally shrinking the molding heat shrink tube by heating treatment, the overlapping portion of the small diameter side heat shrink tube and the large diameter side heat shrink tube can be stably and closely attached to the tapered portion of the shaft body.
  • the eighteenth aspect is a method for manufacturing a medical shaft as described in the sixteenth aspect, in which the transition portion in the shaft body has a stepped portion in which the outer diameter dimension changes in a stepped manner between the small diameter portion and the large diameter portion, and during the heat treatment, the large diameter side heat shrink tube is extended beyond the stepped portion from the large diameter portion of the shaft body and is positioned so as to overlap the small diameter side heat shrink tube in the small diameter portion.
  • the large diameter side heat shrink tube extends beyond the step-like portion from the large diameter portion and is positioned so as to overlap the small diameter side heat shrink tube in the small diameter portion.
  • the 19th aspect is a method for manufacturing a medical shaft according to any one of the 16th to 18th aspects, in which the small diameter side heat shrink tube and the large diameter side heat shrink tube are made of materials that melt with each other by the heat treatment, and the molding heat shrink tube is made of a material that does not melt with respect to the small diameter side heat shrink tube and the large diameter side heat shrink tube by the heat treatment.
  • the heat-treated small-diameter heat-shrinkable tube and the large-diameter heat-shrinkable tube melt together to form an integrated resin tube, so that the shaft body is smoothly covered with the resin tube.
  • the molding heat-shrinkable tube does not melt relative to the small-diameter heat-shrinkable tube and the large-diameter heat-shrinkable tube, the molding heat-shrinkable tube can be easily removed after the heating process is completed.
  • the twentieth aspect is the method for manufacturing a medical shaft described in the seventeenth aspect, in which the inclination angle of the tapered portion of the shaft body is within the range of 3 to 60 degrees.
  • the use of molding heat shrink tubing makes it possible to prevent the small-diameter and large-diameter heat shrink tubing covering the tapered portion from becoming distorted by heat treatment.
  • the inclination angle of the tapered portion 60 degrees or less, the entire shaft body including the tapered portion can be covered with the small-diameter heat shrink tubing and the large-diameter heat shrink tubing.
  • the 21st aspect is a method for manufacturing a medical shaft according to any one of the 16th to 20th aspects, in which the molding heat shrink tube extends from the transition portion of the shaft body to the small diameter portion and the large diameter portion in the longitudinal direction of the shaft body.
  • the 22nd aspect is a method for manufacturing a medical shaft according to any one of the 16th to 21st aspects, in which the small diameter side heat shrink tube and the large diameter side heat shrink tube are fixed in an overlapping state without being glued or welded to the outer circumferential surface of the shaft body over their entire length.
  • the small diameter heat shrink tube and the large diameter heat shrink tube are both fixed to the outer circumferential surface of the shaft body by fitting without being glued or the like. This avoids the adverse effects on the human body caused by the use of adhesives, and also avoids the adverse effects on the shaft body caused by welding.
  • the area of the shaft body that extends from the small diameter portion through the transition portion to the large diameter portion can be covered with a resin tube that is fixed in position relative to the shaft body, while preventing problems caused by the large diameter.
  • FIG. 1 is a cross-sectional view showing a medical shaft according to a first embodiment of the present invention.
  • FIG. 2 is a diagram showing the manufacturing process of the medical shaft shown in FIG. 1, illustrating the state before the first heat treatment.
  • FIG. 2 is a diagram showing the manufacturing process of the medical shaft shown in FIG. 1, illustrating the state after the completion of the first heating process and before the second heating process.
  • FIG. 2 is a diagram showing the manufacturing process of the medical shaft shown in FIG. 1, illustrating the completion state of the secondary heating treatment.
  • FIG. 3 is a cross-sectional view showing a medical shaft according to a second embodiment of the present invention.
  • FIG. 4 is a diagram showing the manufacturing process of the medical shaft shown in FIG. 3, illustrating the state before the first heat treatment.
  • FIG. 4 is a diagram showing the manufacturing process of the medical shaft shown in FIG. 3, illustrating the state after the first heating process and before the second heating process.
  • FIG. 4 is a diagram showing the manufacturing process of the medical shaft shown in FIG. 3, illustrating the completed state of the secondary heating treatment.
  • FIG. 11 is a cross-sectional view showing a medical shaft according to a third embodiment of the present invention.
  • FIG. 6 is a diagram showing the manufacturing process of the medical shaft shown in FIG. 5, illustrating the state before the first heat treatment.
  • FIG. 6 is a diagram showing the manufacturing process of the medical shaft shown in FIG. 5, illustrating the state after the first heating process and before the second heating process.
  • FIG. 6 is a diagram showing the manufacturing process of the medical shaft shown in FIG. 5, illustrating the completion state of the secondary heating treatment.
  • FIG. 5 is a diagram showing the manufacturing process of the medical shaft shown in FIG. 5, illustrating the completion state of the secondary heating treatment.
  • FIG. 11 is a cross-sectional view showing a medical shaft according to a fourth embodiment of the present invention.
  • FIG. 13 is a cross-sectional view showing a medical shaft according to a fifth embodiment of the present invention.
  • FIG. 13 is a cross-sectional view showing a medical shaft according to a sixth embodiment of the present invention.
  • FIG. 1 shows a high-frequency needle 10 as a first embodiment of a medical shaft according to the present invention.
  • the high-frequency needle 10 is a medical instrument that is inserted into the body during treatment of a patient, and is used, for example, to perforate the fossa ovalis of the atrial septum.
  • the high-frequency needle 10 has a structure in which the outer surface of the shaft body 12 is covered with a resin tube 14.
  • the proximal end (left side in FIG. 1) that is on the practitioner side when in use is referred to as the base end of the high-frequency needle 10
  • the distal end (right side in FIG. 1) that is on the patient side is referred to as the tip of the high-frequency needle 10.
  • the shaft body 12 is a hollow, longitudinal member made of a metal such as stainless steel, and has a lumen 16 extending in the axial direction. It is desirable for the shaft body 12 to have a certain degree of flexibility, and it is preferably capable of being plastically deformed into a curved shape, for example, by the practitioner applying force with his or her hand.
  • the shaft body 12 is composed of a small diameter pipe 18 and a large diameter pipe 20.
  • the small diameter pipe 18 extends with a generally constant cross-sectional shape, and has generally constant inner and outer diameter dimensions over its entire length.
  • the inner cavity that penetrates the small diameter pipe 18 in the axial direction forms the lumen 16 of the shaft body 12.
  • a side hole 22 is formed that penetrates part of the peripheral wall at a position a predetermined distance from the tip, and the side hole 22 is connected to the lumen 16.
  • a tip tip 24 is provided at the tip of the small diameter pipe 18.
  • the tip tip 24 in this embodiment is equipped with a drilling head 26.
  • the drilling head 26 has an outer circumferential surface that protrudes from the distal end of the small diameter pipe 18 and is exposed to the outside.
  • the drilling head 26 has a function of forming a patent hole in body tissue by supplying energy from the outside, and can form a patent hole in the body tissue by cauterizing the body tissue with supplied high-frequency energy, for example.
  • the power for heating the drilling head 26 may be supplied by the small diameter pipe 18 by making the small diameter pipe 18 a conductor, or may be supplied by electrical wiring inserted into the inner cavity of the small diameter pipe 18.
  • the small diameter pipe 18 and the large diameter pipe 20 can both be conductors, and power can be supplied to the drilling head 26 by the small diameter pipe 18 and the large diameter pipe 20.
  • the drilling head 26 is preferably less permeable to X-rays (has high X-ray opacity) than the shaft body 12.
  • the drilling head 26 of this embodiment is made of a metal material such as gold, platinum, platinum iridium, tungsten, or stainless steel, which has excellent visibility under X-ray fluoroscopy, and also functions as a tip marker.
  • a coating of X-ray opaque material can be formed on the surface of the drilling head 26 to ensure or improve visibility under X-ray fluoroscopy.
  • the outer periphery of the drilling head 26 has a gradually smaller diameter toward the tip.
  • the shape of the drilling head 26 is not particularly limited, but it is desirable for the distal surface to be a curved surface without corners so that it is less likely to get caught when moving through the lumen. For example, it is shaped like a roughly semi-elliptical body of revolution that is convex toward the distal end, and the overall shape is roughly that of a round-nosed bullet.
  • the drilling head 26 is provided with a cylindrical connection part 28 that extends axially from the base end, and the connection part 28 is inserted and fixed to the tip of the small diameter pipe 18, so that the drilling head 26 is fixedly provided to the tip of the small diameter pipe 18. That is, in this embodiment, the tip tip 24 integrally includes the drilling head 26 and the connection part 28.
  • the tip tip 24 has a generally cylindrical shape with a through hole 30 extending continuously on the central axis between the drilling head 26 and the connecting portion 28.
  • the inner diameter of the through hole 30 is smaller than the inner diameter of the small diameter pipe 18, and the outer diameter of the connecting portion 28 is smaller than the outer diameter of the base end of the drilling head 26 and is generally the same as the inner diameter of the shaft body 12. It is desirable that the axial length of the connecting portion 28 is longer than the axial length of the drilling head 26, thereby improving the fixing strength of the drilling head 26 to the small diameter pipe 18 and improving the transmission efficiency of the sensation transmitted from the drilling head 26 to the practitioner's hand.
  • the large diameter pipe 20 has an outer diameter larger than that of the small diameter pipe 18, and an inner diameter that is approximately the same as or slightly larger than that of the small diameter pipe 18.
  • the large diameter pipe 20 has a tapered portion 32 at its tip, where the outer diameter gradually decreases toward the tip.
  • the inner diameter of the large diameter pipe 20 is approximately constant over its entire length, and the tapered portion 32 becomes thinner toward the tip.
  • the shaft body 12 is formed by inserting the small diameter pipe 18 with the tip 24 attached into the large diameter pipe 20 and fixing the small diameter pipe 18 and the large diameter pipe 20 to each other.
  • the small diameter pipe 18 and the large diameter pipe 20 in the shaft body 12 may be bonded with an adhesive by inserting the small diameter pipe 18 into the inner cavity of the large diameter pipe 20, or may be laser welded.
  • the small diameter pipe 18 is inserted into the inner cavity of the large diameter pipe 20, and the tip of the large diameter pipe 20 is laser welded to the small diameter pipe 18, thereby fixing the small diameter pipe 18 and the large diameter pipe 20 to each other.
  • a tapered portion 32 is formed at the tip of the large diameter pipe 20 by laser welding the small diameter pipe 18 and the large diameter pipe 20.
  • the shaft body 12 has a lumen 16 that runs from the proximal end to the distal end.
  • the base end of the small diameter pipe 18 does not reach the base end of the large diameter pipe 20. Therefore, the lumen 16 of the shaft body 12 is composed of the inner cavity of the small diameter pipe 18 and the inner cavity of the large diameter pipe 20. In this way, by arranging the small diameter pipe 18 on the tip side without reaching the base end of the large diameter pipe 20, it is possible to prevent the shaft body 12 from becoming excessively hard, which would reduce bending followability, or the inner diameter of the lumen 16 in the shaft body 12 from becoming small over the entire length.
  • the small diameter pipe 18 protrudes further toward the tip side than the large diameter pipe 20.
  • the tip of the large diameter pipe 20 is located closer to the base end than the tip of the small diameter pipe 18.
  • the tip portion of the shaft body 12 composed of the small diameter pipe 18 is the small diameter portion 34
  • the base portion of the shaft body 12 composed including the large diameter pipe 20 is the large diameter portion 36.
  • the transition portion 37 in which the outer diameter dimension changes.
  • the axial intermediate portion where the tapered portion 32 of the large diameter pipe 20 in the shaft body 12 is located is a tapered portion 38 in which the outer diameter dimension gradually decreases toward the tip, and the transition portion 37 has a tapered portion 38.
  • the tapered portion 38 is provided over the entire axial length between the small diameter portion 34 and the large diameter portion 36, and the entire transition portion 37 is composed of the tapered portion 38.
  • the small diameter portion 34 formed by the small diameter pipe 18 has a smaller outer diameter dimension than the large diameter portion 36 formed by the large diameter pipe 20, and the tapered portion 38 is provided between the small diameter portion 34 and the large diameter portion 36. Due to the tapered portion 38, the outer diameter dimension of the shaft body 12 is continuously increased from the small diameter portion 34 to the large diameter portion 36.
  • the side hole 22 of the small diameter pipe 18 is located closer to the tip than the large diameter pipe 20 and is not covered by the large diameter pipe 20.
  • the difference ⁇ r in the radial dimension between the small diameter portion 34 and the large diameter portion 36 in the shaft body 12 is preferably within the range of 0.1 to 0.8 mm, and more preferably within the range of 0.2 to 0.3 mm. In this embodiment, the difference ⁇ r in the radial dimension between the small diameter portion 34 and the large diameter portion 36 is set by the radial thickness dimension of the large diameter pipe 20.
  • the inclination angle ⁇ of the tapered portion 38 in the shaft body 12 with respect to the length direction (left-right direction in FIG. 1) is preferably 3° ⁇ 60°.
  • the inclination angle of the tapered portion 38 is substantially constant throughout the entire length direction.
  • the inclination angle of the tapered portion 38 may vary along the length direction, in which case it is preferable that the minimum value of the inclination angle is equal to or greater than the minimum value of the above range, and the maximum value of the inclination angle is equal to or less than the maximum value of the above range.
  • the outer peripheral surface of the shaft body 12 is covered with a resin tube 14.
  • the resin tube 14 is fitted and fixed to the outer peripheral surface of the shaft body 12, thereby being fixed in position relative to the shaft body 12.
  • the resin tube 14 is provided in the area extending from the small diameter portion 34 of the shaft body 12 through the tapered portion 38 to the large diameter portion 36, and in this embodiment, is provided continuously over substantially the entire length of the shaft body 12 from the tip of the small diameter portion 34 to the base end of the large diameter portion 36.
  • the drilling head 26 of the distal tip 24 is not covered by the resin tube 14 and is exposed further distal than the resin tube 14.
  • the resin tube 14 is formed from a resin material having heat shrinkability, which means that the resin tube 14 shrinks when heated.
  • the specific material from which the resin tube 14 is formed is not particularly limited, but it may be formed from a fluororesin such as fluorinated ethylene propylene (FEP), polytetrafluoroethylene (PTFE), or polyvinylidene fluoride (PVDF).
  • FEP fluorinated ethylene propylene
  • PTFE polytetrafluoroethylene
  • PVDF polyvinylidene fluoride
  • the resin tube 14 has a first portion 40 covering the small diameter portion 34 and a second portion 42 covering the large diameter portion 36, which have approximately the same thickness.
  • the resin tube 14 has a third portion 44 covering the tapered portion 38, which has a joint 46 that is thicker than the first portion 40 and/or the second portion 42. In this embodiment, the entire third portion 44 is the joint 46. In other words, the joint 46 is located on the small diameter portion 34 side where the transition portion 37 is located, rather than the end of the large diameter portion 36 in the shaft body 12.
  • the thickness dimension t of the first portion 40 and the second portion 42 is preferably within a range of 0.03 to 0.50 mm, and more preferably within a range of 0.04 to 0.08 mm, taking into account electrical insulation and the like.
  • the maximum thickness dimension T of the third portion 44 is preferably 1.00 mm or less, and more preferably 0.15 mm or less.
  • the resin tube 14 may have a first portion 40 covering the small diameter portion 34 and a second portion 42 covering the large diameter portion 36 that are different in thickness, in which case either portion may be thicker.
  • the resin tube 14 is fixed in an overlapping state to the outer circumferential surface of the shaft body 12 at the first portion 40, the second portion 42, and the third portion 44 without using adhesive.
  • the resin tube 14 in this embodiment is fitted and fixed in a tight contact state to the outer circumferential surface of the shaft body 12. As described below, the resin tube 14 is fitted to the outer circumferential surface of the shaft body 12 by thermal shrinkage.
  • the portion of the outer circumferential surface of the shaft body 12 where the plastic tube 14 is fitted and fixed is preferably roughened.
  • the surface of the shaft body 12 can be suitably roughened by roughening processing such as sand blasting or shot blasting. By carrying out such roughening processing, the resistance of the fitting surface between the shaft body 12 and the plastic tube 14 increases, and the plastic tube 14 is more firmly positioned in the longitudinal direction relative to the shaft body 12.
  • the high-frequency needle 10, in which the surface of the shaft body 12 is covered with a resin tube 14, can be manufactured, for example, by a manufacturing method including the following steps.
  • the shaft body 12 having a small diameter portion 34, a large diameter portion 36, and a tapered portion 38.
  • the small diameter pipe 18 and the large diameter pipe 20 are prepared by drawing, pressing, or the like, and the small diameter pipe 18 is fitted into the large diameter pipe 20 to form the shaft body 12.
  • the tapered portion 32 of the large diameter pipe 20 can be formed, for example, when laser welding to the small diameter pipe 18.
  • the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50 are fitted onto the prepared shaft body 12.
  • the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50 are both made of resin with heat shrinkability that shrinks when heated, and are independent of each other.
  • the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50 are made of the same material. It is desirable that the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50 are made of a material that can be melted and fused together by a secondary heating process described later.
  • the resin material forming the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50 is not particularly limited, but is formed of a fluororesin such as fluorinated ethylene propylene (FEP), polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), etc.
  • FEP fluorinated ethylene propylene
  • PTFE polytetrafluoroethylene
  • PVDF polyvinylidene fluoride
  • the inner diameter of the small diameter side heat shrink tube 48 is smaller than the outer diameter of the large diameter portion 36 of the shaft body 12 and larger than the outer diameter of the small diameter portion 34 of the shaft body 12, so that it can be fitted around the small diameter portion 34.
  • the inner diameter of the large diameter side heat shrink tube 50 is larger than the outer diameter of the large diameter portion 36 of the shaft body 12, so that it can be fitted around the large diameter portion 36.
  • the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50 have different diameters before heat shrinking, and the small diameter side heat shrink tube 48 is smaller in diameter than the large diameter side heat shrink tube 50.
  • the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50 have approximately the same thickness in their initial shapes before heat shrinking.
  • the thickness dimension t1 of the small diameter side heat shrink tube 48 is preferably within the range of 0.03 to 0.50 mm.
  • the thickness dimension t2 of the large diameter side heat shrink tube 50 is preferably within the range of 0.03 to 0.50 mm.
  • the thickness dimension t1 of the small diameter side heat shrink tube 48 and the thickness dimension t2 of the large diameter side heat shrink tube 50 are approximately the same, but they may be different from each other, in which case either one may be thicker.
  • the small diameter side heat shrink tube 48 is fitted onto the small diameter portion 34 of the shaft body 12, and the large diameter side heat shrink tube 50 is fitted onto the large diameter portion 36 of the shaft body 12.
  • This large diameter side heat shrink tube 50 extends from the large diameter portion 36 of the shaft body 12 toward the transition portion 37 (tapered portion 38) side, and is arranged so as to overlap the small diameter side heat shrink tube 48 on the transition portion 37 side of the large diameter portion 36 of the shaft body 12.
  • the small diameter side heat shrink tube 48 is fitted onto the shaft body 12 from the small diameter portion 34 to the middle of the tapered portion 38, and the large diameter side heat shrink tube 50 is fitted onto the shaft body 12 from the large diameter portion 36 to the middle of the tapered portion 38.
  • the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50 inserted on the shaft body 12 are in an overlapping state in which they overlap in radial projection on the outer periphery of the tapered portion 38. That is, the base end of the small diameter side heat shrink tube 48 is located on the base end side of the tip end of the large diameter side heat shrink tube 50, and the base end of the small diameter side heat shrink tube 48 inserted on the tapered portion 38 is inserted into the inner periphery of the tip end of the large diameter side heat shrink tube 50 inserted on the tapered portion 38, providing an overlapping portion 52.
  • the overlapping portion 52 of the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50 is set continuously over almost the entire tapered portion 38.
  • a primary heating process is performed to shrink the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50 by heating.
  • a heating device 54 is disposed on the outer periphery of the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50 that are fitted onto the shaft body 12, and heated air is blown from the heating device 54 toward the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50.
  • the heating device 54 is movable in the axial direction relative to the shaft body 12 while blowing heated air toward the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50, whereby the entire small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50 are heated and thermally shrunk.
  • the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50 which have been warmed by the heated air, are thermally shrunk to a small diameter, and approach the surface of the shaft body 12, as shown in FIG. 2B.
  • the small diameter side heat shrink tube 48 is brought into close contact with the small diameter portion 34 of the shaft body 12
  • the large diameter side heat shrink tube 50 is brought into close contact with the large diameter portion 36, by the primary heating process, and the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50 are positioned relative to the shaft body 12.
  • the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50 are independent and do not fuse with each other, and do not have to be in close contact with the tapered portion 38.
  • a process is carried out in which a molding heat shrink tube 56 is placed in an externally inserted state around the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50 that cover the shaft body 12, as shown in FIG. 2B.
  • the molding heat shrink tube 56 is a resin tube that has heat shrinkability, that is, shrinkage caused by heating.
  • the molding heat shrink tube 56 is preferably made of a material different from the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50.
  • the molding heat shrink tube 56 is preferably made of a material that does not melt at the heating temperature of the secondary heating process described below. As a result, the molding heat shrink tube 56 does not fuse and integrate with the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50 in the secondary heating process described below.
  • the molding heat shrink tube 56 is preferably made of a material that has a higher shrinkage rate due to heating than the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50.
  • the molding heat shrink tube 56 is made thicker than the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50, and has improved shape stability during heat shrinkage.
  • the molding heat shrink tube 56 which is inserted around the small diameter heat shrink tube 48 and the large diameter heat shrink tube 50, is positioned in a position where it can be heated by the heating device 54.
  • the molding heat shrink tube 56 is longer in the longitudinal direction than the tapered portion 38 of the shaft body 12.
  • the molding heat shrink tube 56 is fitted onto the tapered portion 38 of the shaft body 12, and extends beyond the transition portion 37 (tapered portion 38) to both the tip side (small diameter portion 34 side) and the base end side (large diameter portion 36 side), and is also fitted onto the base end of the small diameter portion 34 and the tip end of the large diameter portion 36. Therefore, the entire outer periphery of the overlap portion 52 fitted onto the tapered portion 38 is covered by the molding heat shrink tube 56.
  • a secondary heating process is performed in which the small diameter side heat shrink tube 48, the large diameter side heat shrink tube 50, and the molding heat shrink tube 56 are heated to a temperature higher than that of the primary heating process by a heating device 54.
  • the overlapping portion 52 of the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50 melts and fuses together to form a joint 46, and the joint 46 adheres closely to the surface of the tapered portion 38 of the shaft body 12.
  • the resin tube 14 covering the surface of the shaft body 12 is composed of the integrated small diameter side heat shrink tube 48 and large diameter side heat shrink tube 50.
  • the resin tube 14 is a joint structure in which the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50 are fused together and joined at the joint 46. After the secondary heat treatment, it is desirable for the small diameter heat shrink tube 48 and the large diameter heat shrink tube 50 to form the resin tube 14 as a single unit without a clear boundary, but for example, the boundary of the molten portion may be visible.
  • the resin tube 14 By forming the resin tube 14 using a small diameter heat shrink tube 48 and a large diameter heat shrink tube 50 that have different diameters before heat shrinking, the resin tube 14 can be tightly attached to the outer circumferential surface of the shaft body 12 over its entire length in accordance with the difference in outer diameter dimension between the small diameter portion 34 and the large diameter portion 36 of the shaft body 12. Therefore, the resin tube 14 is fitted into the shaft body 12 over its entire length, covering the surface of the shaft body 12 and fixing its position. In this embodiment, since the surface of the shaft body 12 is roughened, the resin tube 14 is more firmly positioned by being tightly attached to the shaft body 12.
  • the resin tube 14 small diameter side heat shrink tube 48 and large diameter side heat shrink tube 50 after the secondary heating process
  • the resin tube 14 is not glued or welded to the surface of the shaft body 12, but is fitted and fixed. This avoids adverse effects on the patient caused by the use of adhesives, and allows the small diameter side heat shrink tube 48 and large diameter side heat shrink tube 50 to be fixed to the shaft body 12 without heating them to the point of melting them all the way to their inner surfaces.
  • the third portion 44 of the resin tube 14 is formed by fusing together the overlapping small-diameter heat-shrinkable tube 48 and large-diameter heat-shrinkable tube 50, and is thicker than the first portion 40 made up of the small-diameter heat-shrinkable tube 48 alone and/or the second portion 42 made up of the large-diameter heat-shrinkable tube 50 alone, and the entire third portion 44 is the joint portion 46.
  • the joint portion 46 is thicker than either the small-diameter heat-shrinkable tube 48 or the large-diameter heat-shrinkable tube 50 before the heat treatment, and in this embodiment, the thickness of the joint portion 46 is thicker than either the small-diameter heat-shrinkable tube 48 or the large-diameter heat-shrinkable tube 50, which have approximately the same thickness.
  • the thick joint portion 46 is located on the outer circumferential surface of the tapered portion 38 of the shaft body 12, and the entire surface of the tapered portion 38 is covered with the joint portion 46.
  • the thickness dimension of the first portion 40 of the resin tube 14 is less than or equal to the thickness dimension of the small diameter side heat shrink tube 48 before heat shrinkage.
  • the thickness dimension of the second portion 42 of the resin tube 14 is less than or equal to the thickness dimension of the large diameter side heat shrink tube 50 before heat shrinkage.
  • the thickness dimension of the third portion 44 of the resin tube 14 is less than the sum of the thickness dimensions of the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50 before heat shrinkage.
  • the molding heat shrink tube 56 which has been heat-shrunk by the secondary heating process, is pressed against the overlapping portion 52 of the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50, which are in close contact with the surface of the tapered portion 38, from the outer periphery, as shown in FIG. 2C.
  • the molding heat shrink tube 56 extends beyond the transition portion 37 (tapered portion 38) to the tip and base ends, and is in close contact with the area including both ends of the tapered portion 38, so as to cover the base end of the small diameter portion 34 connected to the tapered portion 38 and the tip end of the large diameter portion 36.
  • the entire overlapping portion 52 of the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50, which are superimposed on the tapered portion 38, are fused and integrated while maintaining their shape by the contact of the molding heat shrink tube 56, and are molded into a predetermined shape.
  • the molding heat shrink tube 56 that is pressed against the outer circumferential surface of the third portion 44 of the resin tube 14 during the secondary heat treatment, the third portion 44 of the resin tube 14, which is prone to becoming distorted, such as locally convex, due to the overlap between the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50, can be given a smooth surface shape.
  • the molding heat shrink tube 56 is made of a material different from the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50 that constitute the resin tube 14, so that it can be easily removed from the resin tube 14 after the secondary heat treatment without being melted and integrated with the resin tube 14 during the secondary heat treatment.
  • the molding heat shrink tube 56 is preferably made of a resin material with a melting point different from that of the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50.
  • the process of removing the molding heat shrink tube 56 from the resin tube 14 is desirably performed after cooling the resin tube 14 and the molding heat shrink tube 56 as necessary.
  • the molding heat shrink tube 56 is removed after molding the resin tube 14, there is greater freedom in selecting the thickness and material than with the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50, and it can be made of a material that has excellent shape stability during heat shrinking, for example. Therefore, by using the molding heat shrink tube 56, the outer peripheral surface shape of the third portion 44 of the resin tube 14 can be stably molded into a smooth, predetermined shape during the secondary heat treatment.
  • the high-frequency needle 10 obtained in this manner is used, for example, to perforate the fossa ovalis in the atrial septum. That is, the perforation head 26 of the high-frequency needle 10 inserted into the right atrium is pressed against the blocked portion of the foramen ovale (fossa ovalis) in the atrial septum that separates the right and left atria, and the perforation head 26 generates heat due to the supply of high-frequency power, cauterizing the fossa ovalis and forming a specified patent foramen.
  • the shaft body 12 is made of a conductive metal, and electricity is passed through the shaft body 12 to the drilling head 26.
  • the outer circumferential surface of the shaft body 12 is covered over substantially the entire length from the base end side of the drilling head 26 with an electrically insulating resin tube 14, preventing loss of electrical energy and the risk of electric shock.
  • the high-frequency needle 10 is guided to the right atrium by being inserted into a dilator (not shown) that is inserted into the right atrium.
  • the high-frequency needle 10 has a joint 46 at which the resin tube 14 becomes thick, located in the tapered portion 38 of the shaft body 12, so that partial thickening of the resin tube 14 is unlikely to be a problem when inserting the high-frequency needle 10 into the dilator.
  • the joint 46 is located in the tapered portion 38, even if the joint 46 is made thick, it is unlikely to lead to an increase in the maximum outer diameter of the high-frequency needle 10, and the thick joint 46 does not form a tip portion that is likely to affect insertability.
  • the thick joint 46 is molded into a smooth shape with minimal localized unevenness by the heat shrink tube 56, so there are few problems with it getting caught when inserted into the dilator.
  • an operating handle (not shown) may be attached to the proximal end of the shaft body 12.
  • the operating handle is held and operated by the practitioner, and can be used to insert and remove the shaft body 12, to control its circumferential orientation, and to control the degree of bending and deformation.
  • the operating handle may also function as a hub that opens the lumen 16 of the shaft body 12 proximally.
  • FIG. 3 shows a high-frequency needle 60 as a second embodiment of a medical shaft according to the present invention.
  • the high-frequency needle 60 has a structure in which the outer circumferential surface of the shaft body 12 is covered with a resin tube 62.
  • the same reference numerals are used in the figure to denote components and parts that are substantially the same as those in the first embodiment, and explanations thereof will be omitted.
  • the resin tube 62 has a third section 44 that covers the transition section 37 (tapered section 38) of the shaft body 12, and the thickness of the third section 44 changes in the longitudinal direction (left-right direction in FIG. 3), and the portion of the third section 44 that covers the tip side of the tapered section 38 is a joint 64 that is thicker than the portion that covers the base end side of the tapered section 38.
  • the third section 44 of the resin tube 62 is partially provided with the joint 64 in the longitudinal direction.
  • the longitudinal position of the joint 64 is set on the tip side of the third section 44.
  • the length of the joint 64 is preferably less than half the length of the third section 44 and greater than or equal to 1 ⁇ 4 of the length of the third section 44.
  • the high-frequency needle 60 of this embodiment can be manufactured, for example, through the steps shown in Figures 4A to 4C. That is, in this embodiment as well, first, the small diameter side heat shrink tube 48 is fitted onto the small diameter portion 34 of the shaft body 12, and the large diameter side heat shrink tube 50 is fitted onto the large diameter portion 36 of the shaft body 12. Then, the large diameter side heat shrink tube 50 is extended from the large diameter portion 36 of the shaft body 12 toward the transition portion 37 (tapered portion 38) side, and is arranged so as to overlap the small diameter side heat shrink tube 48 on the transition portion 37 side of the large diameter portion 36 of the shaft body 12. Specifically, as shown in Figure 4A, the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50 are fitted onto the shaft body 12 prepared in advance.
  • the base end of the small diameter side heat shrink tube 48 is inserted into the inner circumference of the tip portion of the large diameter side heat shrink tube 50.
  • the overlapping portion 66 of the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50, which are arranged in an internally and externally inserted state, is arranged on the outer periphery side of the tip portion of the tapered portion 38 of the shaft body 12, and the small diameter side heat shrink tube 48 is not arranged on the outer periphery side of the base end portion of the tapered portion 38.
  • a primary heat treatment is performed to shrink the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50 by heating.
  • the heated small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50 are thermally shrunk to a small diameter, and approach the surface of the shaft body 12, as shown in FIG. 4B.
  • the primary heat treatment causes the small diameter side heat shrink tube 48 to adhere closely to the small diameter portion 34 of the shaft body 12, and the large diameter side heat shrink tube 50 to adhere closely to the large diameter portion 36, so that the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50 are positioned relative to the shaft body 12.
  • the overlapping portions 66 of the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50 are in independent adhesion without being fused to each other.
  • the molding heat shrink tube 56 is placed in an externally inserted state on the shaft body 12 covered with the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50, and a process of performing a secondary heat treatment is performed.
  • the molding heat shrink tube 56 is externally inserted on the tapered portion 38 of the shaft body 12, protrudes beyond the transition portion 37 (tapered portion 38) on both the tip and base ends, and is also externally inserted on the base end of the small diameter portion 34 and the tip end of the large diameter portion 36. Therefore, the overlap portion 66 of the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50 is located on the inner periphery side of the molding heat shrink tube 56.
  • the overlapping portion 66 of the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50 adheres to the surface of the tapered portion 38 of the shaft body 12 by the secondary heat treatment as shown in FIG. 4C, and melts and fuses together to form a thick joint 64.
  • the resin tube 62 covering the surface of the shaft body 12 is composed of the integrated small diameter side heat shrink tube 48 and large diameter side heat shrink tube 50.
  • the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50 overlap only at the tip of the tapered portion 38 of the shaft body 12, so the joint 64 of the resin tube 62 is formed only in the area that covers the tip of the tapered portion 38.
  • the overlapping portion of the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50 does not necessarily have to be set over the entire tapered portion 38 of the shaft body 12, but may be set partially in the length direction.
  • the range of the joint 64 in the third portion 44 of the resin tube 62 can be limited to the tip side, and the third portion 44 of the resin tube 62 covering the tapered portion 38 can be made thin-walled on the base end side where the diameter is large.
  • the lengthwise proportion of the joint 64 in the third portion 44 is not particularly limited.
  • the length dimension of the joint 64 may be greater than half the length dimension of the third portion 44, or less than 1/4 the length dimension of the third portion 44.
  • FIG. 5 shows a high-frequency needle 70 as a third embodiment of a medical shaft according to the present invention.
  • the high-frequency needle 70 also has a structure in which the outer circumferential surface of the shaft body 72 is covered with a resin tube 74.
  • the shaft body 72 of this embodiment is a hollow or solid rod-shaped member made of a metal such as stainless steel, and is configured to include a small diameter rod portion 78 constituting the small diameter portion 76 and a large diameter rod portion 82 constituting the large diameter portion 80.
  • the tip tip 24 is fixed to the tip of the small diameter rod portion 78 (the right end in FIG. 5), and the shaft body 72 (the small diameter rod portion 78 and the large diameter rod portion 82) are made conductive, and power is supplied to the tip tip 24 (the drilling head portion 26), making it possible to cauterize body tissue.
  • the shaft body 72 has a certain degree of flexibility, for example, by setting the outer diameter dimensions of the small diameter rod portion 78 and/or the large diameter rod portion 82 to be somewhat small.
  • the shaft body 72 is shown in its external shape.
  • the large diameter rod portion 82 and the small diameter rod portion 78 each have, for example, an annular or circular cross section and have a substantially constant outer diameter dimension over the entire length.
  • the outer diameter dimension of the large diameter rod portion 82 is larger than the outer diameter dimension of the small diameter rod portion 78.
  • Such a shaft body 72 can be formed, for example, by fixing the small diameter rod portion 78 to the end of the large diameter rod portion 82 by laser welding or the like.
  • the large diameter portion (large diameter pipe) and the small diameter portion (small diameter pipe) may be formed in a mutually connected state by performing a crimping process (diameter reduction process) in the radial direction on one axial side of a metal raw tube having a substantially constant outer diameter dimension and inner diameter dimension.
  • a transition portion 84 in which the outer diameter dimension changes is provided between the small diameter portion 76 and the large diameter portion 80.
  • the small diameter rod portion 78 is directly connected to the end face of the large diameter rod portion 82, and an annular stepped surface 86 that extends in a direction perpendicular to the axial direction is formed around the small diameter rod portion 78 at the end face of the large diameter rod portion 82. Therefore, including the stepped surface 86, a stepped portion 88 in which the outer diameter dimension changes in a step shape is formed between the small diameter portion 76 and the large diameter portion 80, and the transition portion 84 has the stepped portion 88.
  • the resin tube 74 covering the outer peripheral surface of the shaft body 72 has a first portion 90 covering the small diameter portion 76 and a second portion 92 covering the large diameter portion 80 that are approximately the same thickness.
  • the resin tube 74 also has a joint portion 96 in which a third portion 94 covering the stepped portion 88, which is the transition portion 84, is thicker than the first portion 90 and/or the second portion 92. That is, the joint portion 96, which has a thickness dimension greater than either the small diameter side heat shrink tube 98 or the large diameter side heat shrink tube 100, is located on the small diameter portion 76 side where the transition portion 84 is located, rather than the end of the large diameter portion 80 of the shaft body 72.
  • the thickness dimension of the third portion 94 is greater than the thickness dimension of either the small diameter side heat shrink tube 98 or the large diameter side heat shrink tube 100, which are both approximately the same thickness dimension, and the joint 96 is located in a position that covers the end of the small diameter portion 76 on the stepped portion 88 side of the shaft body 72.
  • the high-frequency needle 70 in which the surface of the shaft body 72 is covered with a resin tube 74, can be manufactured, for example, by a manufacturing method including the following steps.
  • a process is carried out to prepare the shaft body 72 having a small diameter portion 76, a large diameter portion 80, and a transition portion 84 (step portion 88). Note that the method for forming the shaft body 72 is not limited.
  • the small diameter side heat shrink tube 98 and the large diameter side heat shrink tube 100 are fitted around the prepared shaft body 72. That is, the small diameter side heat shrink tube 98 is fitted around the small diameter portion 76 of the shaft body 72, and the large diameter side heat shrink tube 100 is fitted around the large diameter portion 80 of the shaft body 72.
  • the large diameter side heat shrink tube 100 is extended from the large diameter portion 80 of the shaft body 72 toward the change portion 84 side, and is arranged so as to overlap the small diameter side heat shrink tube 98 on the change portion 84 side of the large diameter portion 80 of the shaft body 72.
  • the large diameter side heat shrink tube 100 is extended from the large diameter portion 80 of the shaft body 72 beyond the stepped portion 88, and is arranged so as to overlap the small diameter side heat shrink tube 98 at the small diameter portion 76.
  • the inner diameter of the small diameter heat shrink tube 98 is smaller than the outer diameter of the large diameter portion 80 of the shaft body 72, and the small diameter heat shrink tube 98 can be inserted onto the small diameter portion 76 so that its end abuts against the stepped surface 86 of the shaft body 72.
  • the small diameter side heat shrink tube 98 and the large diameter side heat shrink tube 100 fitted onto the shaft body 72 are overlapped in radial projection on the outer periphery of the small diameter portion 76 side where the transition portion 84 is located, rather than the end of the large diameter portion 80 of the shaft body 72. That is, the base end of the small diameter side heat shrink tube 98 is located on the base end side of the tip of the large diameter side heat shrink tube 100, and the base end of the small diameter side heat shrink tube 98 is inserted into the inner circumference of the tip of the large diameter side heat shrink tube 100 to provide an overlap portion 102.
  • the overlap portion 102 of the small diameter side heat shrink tube 98 and the large diameter side heat shrink tube 100 is set continuously with a certain axial dimension from the transition portion 84 (step portion 88) toward the tip.
  • a step of performing a primary heating process is performed to shrink the small diameter side heat shrink tube 98 and the large diameter side heat shrink tube 100 by heating.
  • the small diameter side heat shrink tube 98 and the large diameter side heat shrink tube 100 can be heated by the heating device 54, as in the first and second embodiments.
  • the small diameter side heat shrink tube 98 and the large diameter side heat shrink tube 100 heated by the heating device 54 are thermally shrunk to a small diameter, and approach the surface of the shaft body 72, as shown in FIG. 6B.
  • the small diameter side heat shrink tube 98 is in close contact with the small diameter portion 76 of the shaft body 72 by the primary heating process
  • the large diameter side heat shrink tube 100 is in close contact with the large diameter portion 80 of the shaft body 72, so that the small diameter side heat shrink tube 98 and the large diameter side heat shrink tube 100 are positioned relative to the shaft body 72.
  • the small diameter side heat shrink tube 98 and the large diameter side heat shrink tube 100 are radially separated from each other at the overlap portion 102.
  • a process is performed in which a molding heat shrink tube 104 is placed in an externally inserted state on the small diameter side heat shrink tube 98 and the large diameter side heat shrink tube 100 covering the shaft body 72.
  • This molding heat shrink tube 104 is externally inserted on the transition portion 84 (step portion 88) of the shaft body 72, and extends beyond the transition portion 84 (step portion 88) to both the tip side and the base end side, and is also externally inserted on the base end of the small diameter portion 76 and the tip end of the large diameter portion 80.
  • the molding heat shrink tube 104 has an axial dimension larger than the overlap portion 102 between the small diameter side heat shrink tube 98 and the large diameter side heat shrink tube 100, and the entire overlap portion 102 is covered by the molding heat shrink tube 104.
  • a secondary heating process is carried out in which the small diameter side heat shrink tube 98, the large diameter side heat shrink tube 100, and the molding heat shrink tube 104 are heated to a temperature higher than that of the primary heating process by the heating device 54.
  • the overlapping portion 102 of the small diameter side heat shrink tube 98 and the large diameter side heat shrink tube 100 melts and fuses together to form a joint 96, and the joint 96 covers and adheres to the surface of the end of the stepped portion 88 side of the small diameter portion 76 in the shaft main body 72.
  • the resin tube 74 covering the surface of the shaft main body 72 is composed of the integrated small diameter side heat shrink tube 98 and large diameter side heat shrink tube 100.
  • the molding heat shrink tube 104 which has been heat shrunk by the secondary heating process, is pressed against the overlapping portion 102 of the small diameter heat shrink tube 98 and the large diameter heat shrink tube 100 from the outer periphery, as shown in FIG. 6C.
  • the molding heat shrink tube 104 extends beyond the transition portion 84 (stepped portion 88) to the tip and base ends, and is in close contact with the shaft body 72 so as to cover the base end of the small diameter portion 76 and the tip end of the large diameter portion 80.
  • the molding heat shrink tube 104 is provided to cover the entire overlapping portion 102, so that the entire overlapping portion 102 is fused and integrated while maintaining its shape by the contact of the molding heat shrink tube 104, and is molded into a predetermined shape.
  • the joint 96 formed by overlapping and joining the small diameter side heat shrink tube 98 and the large diameter side heat shrink tube 100 is provided on the small diameter part 76 side where the change part 84 is located, rather than the end of the large diameter part 80 of the shaft body 72, so that the increase in diameter due to the formation of the joint 96 is suppressed, and the same effect as in the first and second embodiments can be achieved.
  • a stepped change part 84 stepped part 88
  • the small diameter side heat shrink tube 98 and the large diameter side heat shrink tube 100 are smoothly connected on the outer circumferential surface of the resin tube 74.
  • FIG. 7 shows a high-frequency needle 110 as a fourth embodiment of a medical shaft according to the present invention.
  • FIG. 8 shows a high-frequency needle 112 as a fifth embodiment of a medical shaft according to the present invention.
  • Both of these are the third embodiment of the medical shaft (high-frequency needle 70) in which the outer circumferential corners of the end of the large diameter portion 80 of the shaft body 72 on the stepped portion 88 side are chamfered.
  • the outer circumferential corners are chamfered in a C-shape
  • the high-frequency needle 112 shown in FIG. 8 the outer circumferential corners are chamfered in an R-shape.
  • an annular tapered surface 114 that gradually becomes smaller in diameter toward the tip side (small diameter portion 76 side) is provided at the outer circumferential end of the end portion of the large diameter portion 80 on the stepped portion 113 side, and the tapered surface 114 is provided continuously from the outer circumferential end of the stepped surface 86 to the base end side.
  • the transition portion 116 (stepped portion 113) is formed by including the tapered surface 114 in addition to the stepped surface 86, and the base end of the tapered surface 114 (the outer circumferential end of the tapered surface 114, point P1 in Figure 7) can be understood as the end portion of the large diameter portion 80 in the shaft body 72.
  • a joint 118 having a thickness greater than both the small diameter side heat shrink tube 98 and the large diameter side heat shrink tube 100 is provided to cover the transition portion 116 (tapered surface 114 and stepped surface 86), and the joint 118 is located closer to the small diameter portion 76 where the transition portion 116 is located than the end (P1) of the large diameter portion 80 of the shaft body 72.
  • an annular curved surface 120 that gradually becomes smaller in diameter toward the tip side (small diameter portion 76 side) is provided at the outer circumferential end of the end portion of the large diameter portion 80 on the stepped portion 119 side, and the curved surface 120 is provided continuously from the outer circumferential end of the stepped surface 86 to the base end side.
  • the transition portion 122 (stepped portion 119) is formed by including the curved surface 120 in addition to the stepped surface 86, and the base end of the curved surface 120 (the outer circumferential end of the curved surface 120, point P2 in Figure 8) can be understood as the end portion of the large diameter portion 80 in the shaft body 72.
  • a joint 124 having a thickness greater than both the small diameter side heat shrink tube 98 and the large diameter side heat shrink tube 100 is provided to cover the transition portion 122 (the curved surface 120 and the stepped surface 86), and the joint 124 is located closer to the small diameter portion 76 where the transition portion 122 is located than the end (P2) of the large diameter portion 80 of the shaft body 72.
  • the high-frequency needle 110 in the fourth embodiment and the high-frequency needle 112 in the fifth embodiment, which are constructed as described above, are simply the high-frequency needle 70 in the third embodiment, in which the outer circumferential corners of the end of the large diameter portion 80 on the stepped portion 88 side are chamfered, and therefore can exhibit the same effect as the high-frequency needle 70 in the third embodiment.
  • the angularity of the outer circumferential corners can be eliminated, and the joints 118, 124 can be made thicker, which can reduce the risk that, for example, the angularity of the outer circumferential corners will get caught when a dilator or the like is inserted, or that the outer circumferential corners will break through the resin tube 74 and protrude when the high-frequency needles 110, 112 are bent.
  • the high-frequency needle 110 in the fourth embodiment and the high-frequency needle 112 in the fifth embodiment can be manufactured by the same manufacturing method as the high-frequency needle 70 in the third embodiment.
  • FIG. 9 shows a high-frequency needle 130 as a sixth embodiment of the medical shaft according to the present invention.
  • an intermediate ring 132 having an outer diameter smaller than that of the large diameter portion 80 is attached in an extrapolated state to the end of the small diameter portion 76 of the shaft body 72 on the stepped portion 88 side in the medical shaft (high-frequency needle 70) of the third embodiment.
  • the change portion 134 in which the outer diameter dimension changes between the small diameter portion 76 and the large diameter portion 80 is configured to include the intermediate ring 132 in addition to the stepped surface 86, and has a stepped portion 136 in which the outer diameter dimension changes in multiple steps between the small diameter portion 76 and the large diameter portion 80.
  • the base end side end face of the intermediate ring 132 abuts against the stepped surface 86, so that no gap is provided between the large diameter portion 80 and the intermediate ring 132 in the axial direction.
  • a joint 138 having a thickness greater than either the small diameter side heat shrink tube 98 or the large diameter side heat shrink tube 100 is provided to cover the transition portion 134 (step portion 136).
  • the thickness of the joint 138 is greater than either the small diameter side heat shrink tube 98 or the large diameter side heat shrink tube 100, which have approximately the same thickness.
  • the joint 138 is located closer to the small diameter portion 76, where the transition portion 134 is located, than the end of the large diameter portion 80 of the shaft body 72. As a result, the shaft body 72, including the intermediate ring 132, is covered with the resin tube 74.
  • the high-frequency needle 130 in this embodiment can also achieve the same effect as the high-frequency needle 70 described in the third embodiment.
  • a stepped portion 136 in which the outer diameter dimension changes in multiple steps can be formed as the changing portion 134.
  • the high-frequency needle 130 of this embodiment can be basically manufactured by the same manufacturing method as the high-frequency needle 70 of the third embodiment.
  • the small-diameter heat shrink tube 98 when the small-diameter heat shrink tube 98 is inserted around the small-diameter portion 76, the small-diameter heat shrink tube 98 may be inserted around the intermediate ring 132 in addition to the small-diameter portion 76.
  • the small-diameter heat shrink tube 98 may be inserted around the small-diameter portion 76 on the tip side of the intermediate ring 132, so that the base end face of the small-diameter heat shrink tube 98 abuts on the tip end face of the intermediate ring 132.
  • the large-diameter heat shrink tube 100 when the large-diameter heat shrink tube 100 is inserted around the large-diameter portion 80, it is extended from the large-diameter portion 80 to the change portion 134 side, and is arranged in an overlapping state with the base end portion of the small-diameter heat shrink tube 98 on the change portion 134 side of the large-diameter portion 80 (for example, inserted around the outer circumferential surface of the intermediate ring 132 or at the tip side of the intermediate ring 132).
  • a high-frequency needle is shown as an example of a medical shaft, and a resin tube is provided as an insulating coating layer when electricity is applied, but the resin tube is not necessarily limited to one that constitutes the insulating coating layer.
  • the resin tube can also be used, for example, as a protective layer that protects the surface of the shaft body.
  • the medical shaft is not limited to one used in treatment of the human body, and may be one used, for example, in treatment of animals other than humans.
  • the shaft body is not limited to a structure that combines a small diameter pipe 18 and a large diameter pipe 20, such as the shaft body 12 shown in the first and second embodiments, and may be constructed as a single member, for example.
  • the shaft body may be a solid rod, and the material is not limited.
  • the shaft body is not limited to a structure that includes a tip 24.
  • the tapered portion 38 of the shaft body 12 is formed by melting when the tip portion of the large diameter pipe 20 is laser welded to the small diameter pipe 18.
  • the tapered portion 38 of the shaft body 12 can also be formed from a brazing material separate from the large diameter pipe 20, for example, when the small diameter pipe 18 and the tip side of the large diameter pipe 20 are fixed by brazing.
  • the joint 46 of the resin tube 14 formed by the overlap portion 52 of the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50 may cover the entire tapered portion 38 including both longitudinal ends of the tapered portion 38 of the shaft body 12, or may cover only one longitudinal end of the tapered portion 38.
  • the overlap portion 52 may be positioned in an extrapolated state in an intermediate portion away from both longitudinal ends of the tapered portion 38, and the joint 46 of the resin tube 14 may be provided to cover the intermediate portion of the tapered portion 38.
  • the resin tubes 14, 74 that cover the shaft bodies 12, 72 are formed by a primary heat treatment and a secondary heat treatment.
  • the small diameter side heat shrink tube 48, 98, the large diameter side heat shrink tube 50, 100, and the molding heat shrink tube 56, 104 may be placed in an externally inserted state on the shaft bodies 12, 72, respectively, and the resin tubes 14, 74 may be formed by a single heat treatment.
  • the resin tubes 14, 74 may also be formed by three or more heat treatments.
  • the small diameter side heat shrink tube 48, 98 and the large diameter side heat shrink tube 50, 100 are fitted and fixed without being bonded or welded to the outer circumferential surface of the shaft body 12, 72, but at least one of the small diameter side heat shrink tube 48, 98 and the large diameter side heat shrink tube 50, 100 may be bonded or welded to the outer circumferential surface of the shaft body 12, 72.
  • at least one of the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50 is bonded or welded to the shaft body 12 in the small diameter portion 34 and/or the tapered portion 38 and its vicinity. This makes it possible to more advantageously prevent the heat shrink tube 48 (50) from shifting relative to the shaft body 12 when the tip portion of the shaft body 12 is curved.
  • the heat shrink tube 56 for molding is used to control the shape of the overlapping portion 52 of the heat shrink tubes 48, 50 that cover the tapered portion 38, and therefore the heat shrink tube 56 for molding does not need to be sufficiently heat shrunk at the portion where it is inserted into the small diameter portion 34 or the large diameter portion 36 of the shaft body 12.
  • the heat shrink tube 56 for molding it is also possible to heat shrink mold the joint 46 without using the heat shrink tube for molding 56.
  • the specific shape of the change part of the shaft body is not limited to the above-mentioned embodiments.
  • the convex corner part on the outer circumferential side (large diameter side) of the stepped surface 86 of the shaft body 72 is chamfered (tapered surface 114 or curved surface 120), but in addition to or instead of that, the concave corner part on the inner circumferential side (small diameter side) of the stepped surface 86 may be chamfered. That is, at the base end of the small diameter part, it is also possible to provide a tapered surface or curved surface that widens toward the outer circumferential side as it approaches the base end side (stepped surface 86 side).
  • the intermediate ring 132 of the sixth embodiment it is also possible to adopt the intermediate ring 132 of the sixth embodiment, and it is also possible to adopt an intermediate ring whose outer diameter dimension changes in multiple stages or a single or multiple intermediate ring whose outer diameter dimension changes in a tapered manner.
  • the intermediate ring 132 was attached in an externally inserted state to the end of the small diameter portion 76 on the stepped portion 88 side, but the intermediate ring may be provided at a position slightly spaced axially from the large diameter portion, and the base end face of the intermediate ring and the stepped surface may not be in contact.
  • the small diameter side heat shrink tube 48 is fitted from the small diameter portion 34 to the tapered portion 38, and the large diameter side heat shrink tube 50 is fitted from the large diameter portion 36 to the tapered portion 38, and these small diameter side heat shrink tube 48 and large diameter side heat shrink tube 50 are overlapped at the tapered portion 38, but this is not limited to the above embodiment.
  • an intermediate tube having a diameter dimension intermediate between the small diameter side heat shrink tube and the large diameter side heat shrink tube may be used, and the small diameter side heat shrink tube or the large diameter side heat shrink tube may be configured including the intermediate tube.
  • Such an intermediate tube is disposed in the tapered portion 38, overlapping and heat-welding the large-diameter heat-shrinkable tube at one axial end, and overlapping and heat-welding the small-diameter heat-shrinkable tube at the other axial end.
  • This type of configuration makes it possible to advantageously deal with cases where the diameter change in the tapered portion 38 is large or the axial length is long.
  • the small diameter side heat shrink tube and/or the large diameter side heat shrink tube of the present invention do not each need to be a single tube, but may each be comprised of two or more tubes with different diameter dimensions, a tube covering the small diameter portion or the large diameter portion, and a tube covering the transition portion.
  • the thickness dimension of the joints 46, 64, 96, 118, 124, 138 was larger than the thickness dimension of each of the small diameter side heat shrink tube 48, 98 and the large diameter side heat shrink tube 50, 100, but this is not limited to this embodiment.
  • the small diameter side heat shrink tube and the large diameter side heat shrink tube may have different thickness dimensions.
  • the transition portion is configured by a stepped portion as shown in FIG. 6A, and the large diameter side heat shrink tube (e.g., the large diameter side heat shrink tube 100 in FIG. 6A) has a larger thickness dimension than the small diameter side heat shrink tube (e.g., the small diameter side heat shrink tube 98 in FIG.
  • the thickness dimension of the joint (e.g., the joint 96 in FIG. 6C) is larger than the thickness dimension of the small diameter side heat shrink tube, but it is also assumed that the thickness dimension of the joint (e.g., the joint 96 in FIG. 6C) may become smaller than the thickness dimension of the large diameter side heat shrink tube due to melting and flowing of the large diameter side heat shrink tube.
  • High-frequency needle (medical shaft, first embodiment) 12 Shaft body 14 Resin tube 16 Lumen 18 Small diameter pipe 20 Large diameter pipe 22 Side hole 24 Distal tip 26 Drilling head 28 Connection portion 30 Through hole 32 Tapered portion 34 Small diameter portion 36 Large diameter portion 37 Transition portion 38 Tapered portion 40 First portion 42 Second portion 44 Third portion 46 Joint portion 48 Small diameter side heat shrink tube 50 Large diameter side heat shrink tube 52 Overlap portion 54 Heating device 56 Molding heat shrink tube 60 High frequency needle (medical shaft, second embodiment) 62 Resin tube 64 Joint portion 66 Overlap portion 70 High-frequency needle (medical shaft, third embodiment) 72 Shaft body 74 Resin tube 76 Small diameter portion 78 Small diameter rod portion 80 Large diameter portion 82 Large diameter rod portion 84 Transition portion 86 Step surface 88 Step portion 90 First portion 92 Second portion 94 Third portion 96 Joint portion 98 Small diameter side heat shrink tube 100 Large diameter side heat shrink tube 102 Overlap portion 104 Molding heat shrink tube 110 High frequency needle (medical shaft, fourth embodiment) 112 High frequency needle (medical shaft, fifth embodiment)

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Abstract

The present invention provides a medical shaft which has a novel structure and which makes it possible to fit, to a fixed position, a resin tube that covers a region of a shaft body from a small-diameter portion to a large-diameter portion, while suppressing the occurrence of problems caused by an increase in diameter.　Provided is a medical shaft 10 wherein: a shaft body 12 is provided with a change part 37 in which the outer diameter dimension changes between a small-diameter portion 34 and a large-diameter portion 36; a region of the shaft body 12 which is from the small-diameter portion 34, through the change part 37, and to the large-diameter portion 36 is continuously covered in the lengthwise direction by a resin tube 14; the resin tube 14 has a structure in which a small-diameter side heat-shrink tube 48 that covers the small-diameter portion 34 and a large-diameter side heat-shrink tube 50 that covers the large-diameter portion 36 are joined; and a joining part 46, which has a larger thickness dimension than one of the small-diameter side heat-shrink tube 48 and the large-diameter side heat-shrink tube 50, is positioned further to the small-diameter portion 34 side at which the change part 37 is positioned than an end part of the large-diameter portion 36 of the shaft body 12.

Description

医療用シャフトと医療用シャフトの製造方法Medical shaft and manufacturing method thereof
　本発明は、患者の体外から操作して体内での処置を施す際に用いられる医療用シャフトと医療用シャフトの製造方法とに関するものである。 The present invention relates to a medical shaft that is used to perform treatment inside a patient's body by operating it from outside the body, and a method for manufacturing the medical shaft.
　医療分野では、患者の体外から操作して患者の体内での処置を施すために各種の長手状の医療用シャフトが用いられている。例えば、国際公開第２０１３／１７９１０３号（特許文献１）に開示されている体内の特定組織へ電気エネルギーを与えるチューブ状の医療機器（穿刺ロッド）や、治療用カテーテルなどが知られている。 In the medical field, various longitudinal medical shafts are used to operate from outside the patient's body to perform treatment inside the patient's body. For example, a tubular medical device (puncture rod) that delivers electrical energy to specific tissues inside the body, as disclosed in International Publication No. 2013/179103 (Patent Document 1), and a therapeutic catheter are known.
　ところで、このような医療用シャフトでは、生体組織の保護、エネルギーロスの防止、耐久性の確保等の何らかの目的をもって、シャフト本体の外周面を覆う樹脂層を設ける場合がある。 Incidentally, such medical shafts may have a resin layer covering the outer surface of the shaft body for some purpose, such as protecting biological tissue, preventing energy loss, and ensuring durability.
　また、医療用シャフトは、ダイレータやシース、カテーテルなどを通じて体内の所定部位に差し入れられることがあり、ダイレータ等に摺接しても樹脂層による被覆がシャフト本体に対して剥がれたり位置ずれしたりせずに安定して保持されることが要求される。 In addition, medical shafts are sometimes inserted into a specific location inside the body through a dilator, sheath, catheter, etc., and are required to be stably held in place by the resin layer coating, without peeling off or shifting, even when in sliding contact with the dilator, etc.
　このような事情から、シャフト本体の外周面を覆う樹脂層を実現するに際して、例えばシャフト本体の外周面に樹脂材を塗布して樹脂層を形成することも考えられるが、それでは一定で且つ充分な厚さの樹脂層を形成することが難しい。一方、一定厚さで別途に形成した樹脂チューブをシャフト本体に外挿して接着剤で固着することも考えられるが、接着作業が面倒であることに加えて、接着剤の生体組織への悪影響なども懸念される。 For these reasons, when realizing a resin layer covering the outer periphery of the shaft body, it is possible to form the resin layer by, for example, applying a resin material to the outer periphery of the shaft body, but this makes it difficult to form a resin layer of a uniform and sufficient thickness. On the other hand, it is also possible to insert a resin tube formed separately to a uniform thickness onto the shaft body and fix it with an adhesive, but in addition to the troublesome bonding process, there are concerns about the adverse effects of the adhesive on biological tissue.
国際公開第２０１３／１７９１０３号International Publication No. 2013/179103
　そこで、本発明者は、シャフト本体の外周面に熱収縮チューブを嵌着することで、樹脂層をシャフト本体に対して位置固定に設けることを検討した。 The inventor therefore considered fitting a heat shrink tube onto the outer circumferential surface of the shaft body to fix the resin layer in position relative to the shaft body.
　ところが、シャフト本体の先端部分が小径とされている場合など、シャフト本体の外径寸法が長さ方向で異なる場合には、熱収縮チューブをシャフト本体に対して全長に亘って嵌着状態で安定して固着することが難しいという、新たな課題が存在することが分かった。即ち、シャフト本体の大径部分に外挿可能な熱収縮チューブを採用すると、シャフト本体の小径部分では熱収縮チューブが充分に収縮されずに隙間が発生して固着力が発揮され難い。一方、シャフト本体の小径部分でも嵌着されるような熱収縮チューブでは、熱収縮率の大きい大径の熱収縮チューブを採用することとなり、熱収縮チューブの材質選択の自由度が大幅に制限されるだけでなく、熱収縮後の樹脂層の厚さ寸法が大きくなって医療用シャフトの大径化による挿通性能の阻害等を避け難いという問題が発生する。 However, it was found that when the outer diameter of the shaft body varies along its length, such as when the tip of the shaft body is small in diameter, a new problem exists in that it is difficult to stably attach the heat shrink tube to the shaft body in a fitted state over its entire length. In other words, when a heat shrink tube that can be fitted onto the large diameter part of the shaft body is used, the heat shrink tube does not shrink sufficiently in the small diameter part of the shaft body, creating gaps and making it difficult to exert its fixing force. On the other hand, when a heat shrink tube is fitted onto the small diameter part of the shaft body, a large diameter heat shrink tube with a large heat shrink rate is used, which not only significantly limits the freedom of choice of material for the heat shrink tube, but also creates problems such as the thickness dimension of the resin layer after heat shrinkage becoming large, making it difficult to avoid impeding the insertion performance due to the large diameter of the medical shaft.
　本発明の解決課題は、長さ方向で外径寸法が異なるシャフト本体を備えた医療用シャフトを対象とするものであって、シャフト本体における小径部分から大径部分に至る領域を被覆する樹脂チューブを、大径化による問題の発生を抑えながら、シャフト本体に対して全長にわたって位置固定に装着することができる、新規な構造の医療用シャフトを提供することにある。 The problem to be solved by this invention is to provide a medical shaft with a shaft body whose outer diameter varies along its length, and which has a novel structure that allows a plastic tube that covers the area of the shaft body from the small diameter section to the large diameter section to be attached in a fixed position over the entire length of the shaft body while minimizing problems caused by the large diameter.
　また、本発明は、長さ方向で外径寸法が異なるシャフト本体を備えた医療用シャフトを対象として、シャフト本体における小径部分から大径部分に至る領域を被覆する樹脂チューブを、大径化による問題の発生を抑えながら、シャフト本体に対して全長にわたって位置固定に装着することができる、新規な医療用シャフトの製造方法を提供することも目的とする。 The present invention also aims to provide a new method for manufacturing medical shafts, which is targeted at medical shafts having a shaft body whose outer diameter dimensions vary along the length, and which allows a resin tube that covers the area of the shaft body from the small diameter portion to the large diameter portion to be attached in a fixed position over the entire length of the shaft body while minimizing problems caused by increasing the diameter.
　以下、本発明を把握するための好ましい態様について記載するが、以下に記載の各態様は、例示的に記載したものであって、適宜に互いに組み合わせて採用され得るだけでなく、各態様に記載の複数の構成要素についても、可能な限り独立して認識及び採用することができ、適宜に別の態様に記載の何れかの構成要素と組み合わせて採用することもできる。それによって、本発明では、以下に記載の態様に限定されることなく、種々の別態様が実現され得る。 Below, preferred embodiments for understanding the present invention are described, but each embodiment described below is described as an example, and not only can they be used in combination with each other as appropriate, but the multiple components described in each embodiment can also be recognized and used independently as far as possible, and can also be used in combination with any of the components described in another embodiment as appropriate. As a result, the present invention is not limited to the embodiments described below, and various alternative embodiments can be realized.
　第１の態様は、動物への施術に際して体内に差し入れられる医療用シャフトであって、シャフト本体は、長さ方向で外径寸法が異ならされて小径部分と大径部分とを有しており、該小径部分と該大径部分との間には外径寸法が変化する変化部が設けられている一方、該シャフト本体は、該小径部分から該変化部を経て該大径部分に至る領域が長さ方向で連続して樹脂チューブで被覆されていると共に、該樹脂チューブが、該小径部分を覆う小径側熱収縮チューブと該大径部分を覆う大径側熱収縮チューブとが接合された接合構造体とされており、該小径側熱収縮チューブと該大径側熱収縮チューブとにおける厚さ寸法の小さい方の熱収縮チューブの配設領域に設けられて且つ該厚さ寸法の小さい方の熱収縮チューブよりも厚さ寸法が大きくされた接合部が、該シャフト本体の該大径部分の端部よりも該変化部が位置する該小径部分側に位置せしめられているものである。 The first aspect is a medical shaft that is inserted into the body of an animal during treatment, and the shaft body has a small diameter portion and a large diameter portion with different outer diameter dimensions in the length direction, and a transition portion where the outer diameter dimension changes is provided between the small diameter portion and the large diameter portion, while the shaft body is continuously covered in the length direction with a resin tube in the area from the small diameter portion through the transition portion to the large diameter portion, and the resin tube is a joint structure in which a small diameter side heat shrink tube covering the small diameter portion and a large diameter side heat shrink tube covering the large diameter portion are joined, and a joint portion that is provided in the arrangement area of the heat shrink tube with the smaller thickness between the small diameter side heat shrink tube and the large diameter side heat shrink tube and has a thickness dimension larger than that of the heat shrink tube with the smaller thickness is positioned on the small diameter portion side where the transition portion is located, rather than the end of the large diameter portion of the shaft body.
　本態様に従う構造とされた医療用シャフトによれば、小径部分と大径部分とを有するシャフト本体を被覆する樹脂チューブが、シャフト本体の小径部分を覆う小径側熱収縮チューブとシャフト本体の大径部分を覆う大径側熱収縮チューブとによって構成されている。これにより、例えば、小径側熱収縮チューブの熱収縮前の直径を大径側熱収縮チューブの熱収縮前の直径よりも小さくすることで、小径側熱収縮チューブをシャフト本体の小径部分に嵌着させつつ、大径側熱収縮チューブをシャフト本体の大径部分に嵌着させることができて、樹脂チューブがシャフト本体に対して全長にわたって位置合わせされた状態で装着される。 In a medical shaft constructed according to this embodiment, the resin tube covering the shaft body having a small diameter portion and a large diameter portion is composed of a small diameter side heat shrink tube that covers the small diameter portion of the shaft body and a large diameter side heat shrink tube that covers the large diameter portion of the shaft body. As a result, for example, by making the diameter of the small diameter side heat shrink tube before heat shrinking smaller than the diameter of the large diameter side heat shrink tube before heat shrinking, it is possible to fit the small diameter side heat shrink tube into the small diameter portion of the shaft body while fitting the large diameter side heat shrink tube into the large diameter portion of the shaft body, and the resin tube is attached in a state of being aligned with the shaft body over its entire length.
　また、樹脂チューブは、小径側熱収縮チューブと大径側熱収縮チューブの接合構造体とされていることにより、それら小径側熱収縮チューブと大径側熱収縮チューブの接合部が、少なくとも厚さ寸法が小さい方の熱収縮チューブよりも厚肉となるが、当該厚肉とされた接合部がシャフト本体の大径部分の端部よりも変化部が位置する小径部分側の位置に配されている。このように、小径側熱収縮チューブと大径側熱収縮チューブとの接合構造を採用することで厚肉となる接合部が、シャフト本体において大径部分よりも小径とされた小径部分側に位置していることにより、接合部の厚肉化に起因する医療用シャフトの大径化が問題になり難い。 In addition, because the resin tube is a joint structure between the small diameter heat shrink tube and the large diameter heat shrink tube, the joint between the small diameter heat shrink tube and the large diameter heat shrink tube is thicker than the heat shrink tube with the smaller thickness dimension, but the thick joint is located closer to the small diameter portion where the transition portion is located than the end of the large diameter portion of the shaft body. In this way, by adopting a joint structure between the small diameter heat shrink tube and the large diameter heat shrink tube, the thick joint is located on the small diameter portion side of the shaft body that is smaller in diameter than the large diameter portion, so that the increase in diameter of the medical shaft due to the thick joint is less likely to be a problem.
　第２の態様は、第１の態様に記載された医療用シャフトにおいて、前記シャフト本体における前記変化部が、前記小径部分と前記大径部分との間において外径寸法が長さ方向で変化するテーパ状部分を有しており、前記樹脂チューブにおける前記接合部が、該テーパ状部分を覆う部位に位置せしめられているものである。 The second aspect is the medical shaft described in the first aspect, in which the transition portion in the shaft body has a tapered portion in which the outer diameter dimension changes in the length direction between the small diameter portion and the large diameter portion, and the joint portion in the resin tube is positioned in a portion that covers the tapered portion.
　本態様に従う構造とされた医療用シャフトによれば、小径部分と大径部分との間にテーパ状部分が設けられていることから、小径部分と大径部分の外径寸法の変化が比較的緩やかであり、シャフト本体が樹脂チューブで被覆された際にも、樹脂チューブにおいてテーパ状部分を覆う部位の外径寸法の変化が比較的緩やかとされると共に、樹脂チューブにおける局所的な薄肉化等も回避しやすい。特に、小径側熱収縮チューブや大径側熱収縮チューブよりも厚さ寸法が大きい接合部が大径部分よりも小径なテーパ状部分に設けられることで、接合部の形成位置における過度な大径化が抑制されて、例えば本態様に係る医療用シャフトがダイレータ等に挿通された場合にも、医療用シャフトがダイレータ等に引っ掛かるおそれが低減され得る。 In a medical shaft constructed according to this embodiment, a tapered portion is provided between the small diameter portion and the large diameter portion, so that the change in the outer diameter dimension between the small diameter portion and the large diameter portion is relatively gradual, and even when the shaft body is covered with a resin tube, the change in the outer diameter dimension of the resin tube at the portion covering the tapered portion is relatively gradual, and local thinning of the resin tube is easily avoided. In particular, by providing a joint having a thickness larger than that of the small diameter side heat shrink tube and the large diameter side heat shrink tube in a tapered portion having a smaller diameter than the large diameter portion, excessive increase in diameter at the position where the joint is formed is suppressed, and for example, even when the medical shaft according to this embodiment is inserted into a dilator or the like, the risk of the medical shaft getting caught on the dilator or the like can be reduced.
　第３の態様は、第１の態様に記載された医療用シャフトにおいて、前記シャフト本体における前記変化部が、前記小径部分と前記大径部分との間において外径寸法が段差状に変化する段差状部分を有しており、前記樹脂チューブにおける前記接合部が、該シャフト本体における前記小径部分の該段差状部分側の端部を覆う部位に位置せしめられているものである。 The third aspect is the medical shaft described in the first aspect, in which the transition portion in the shaft body has a stepped portion where the outer diameter dimension changes in a stepped manner between the small diameter portion and the large diameter portion, and the joint portion in the resin tube is positioned at a portion that covers the end portion of the small diameter portion in the shaft body on the stepped portion side.
　本態様に従う構造とされた医療用シャフトによれば、小径部分と大径部分との間において外径寸法が段差状に変化する場合にも、樹脂チューブにおける接合部が小径部分の段差状部分側の端部を覆う部位に設けられることで、かかる部位における樹脂チューブの肉厚が大きくなり、かかる厚肉とされた樹脂チューブによって外径寸法の段差状の変化が軽減乃至は解消され得る。その結果、樹脂チューブにおいてシャフト本体の小径部分を覆う部分（小径側熱収縮チューブ）とシャフト本体の大径部分を覆う部分（大径側熱収縮チューブ）との外径寸法の急激な変化が抑えられて、樹脂チューブの外周面において小径側熱収縮チューブと大径側熱収縮チューブとが比較的緩やかな湾曲面形状をもって接続され得る。これにより、シャフト本体の外径寸法が段差状に変化する場合でも、医療用シャフトの外周面における角状の突出が容易に回避されて、例えば本態様に係る医療用シャフトがダイレータ等に挿通された場合にも、医療用シャフトがダイレータ等に引っ掛かるおそれが低減され得る。 With the medical shaft constructed according to this embodiment, even if the outer diameter changes stepwise between the small diameter portion and the large diameter portion, the joint in the resin tube is provided at the portion covering the end of the small diameter portion on the step-like portion side, so that the thickness of the resin tube at this portion is increased, and the step-like change in the outer diameter can be reduced or eliminated by the thick-walled resin tube. As a result, a sudden change in the outer diameter between the portion of the resin tube covering the small diameter portion of the shaft body (small diameter side heat shrink tube) and the portion of the resin tube covering the large diameter portion of the shaft body (large diameter side heat shrink tube) is suppressed, and the small diameter side heat shrink tube and the large diameter side heat shrink tube can be connected with a relatively gently curved surface shape on the outer circumferential surface of the resin tube. As a result, even if the outer diameter of the shaft body changes stepwise, angular protrusions on the outer circumferential surface of the medical shaft can be easily avoided, and for example, even when the medical shaft according to this embodiment is inserted into a dilator or the like, the risk of the medical shaft getting caught on the dilator or the like can be reduced.
　第４の態様は、動物への施術に際して体内に差し入れられる医療用シャフトであって、シャフト本体は、長さ方向で外径寸法が異ならされて小径部分と大径部分とを有しており、該小径部分と該大径部分との間には外径寸法が変化する変化部が設けられている一方、該シャフト本体は、該小径部分から該変化部を経て該大径部分に至る領域が長さ方向で連続して樹脂チューブで被覆されていると共に、該樹脂チューブが、該小径部分を覆う小径側熱収縮チューブと該大径部分を覆う大径側熱収縮チューブとが接合された接合構造体とされており、該シャフト本体の該大径部分の端部よりも該変化部が位置する該小径部分側に位置して、該小径側熱収縮チューブと該大径側熱収縮チューブとが相互に重ね合わされて接合されているものである。 The fourth aspect is a medical shaft that is inserted into the body of an animal during treatment, the shaft body having a small diameter portion and a large diameter portion with different outer diameter dimensions in the length direction, a transition portion where the outer diameter dimension changes is provided between the small diameter portion and the large diameter portion, the shaft body is covered with a resin tube continuously in the length direction in the region from the small diameter portion through the transition portion to the large diameter portion, and the resin tube is a joint structure in which a small diameter side heat shrink tube covering the small diameter portion and a large diameter side heat shrink tube covering the large diameter portion are joined, and the small diameter side heat shrink tube and the large diameter side heat shrink tube are overlapped and joined to each other at a position closer to the small diameter portion side where the transition portion is located than the end of the large diameter portion of the shaft body.
　本態様に従う構造とされた医療用シャフトによれば、第１の態様と同様に、小径側熱収縮チューブをシャフト本体の小径部分に嵌着させつつ、大径側熱収縮チューブをシャフト本体の大径部分に嵌着させることができて、樹脂チューブがシャフト本体に対して全長にわたって位置合わせされた状態で装着される。 In a medical shaft constructed according to this embodiment, as in the first embodiment, the small diameter heat shrink tube can be fitted to the small diameter portion of the shaft body while the large diameter heat shrink tube can be fitted to the large diameter portion of the shaft body, and the plastic tube is attached in a state where it is aligned with the shaft body over its entire length.
　また、小径側熱収縮チューブと大径側熱収縮チューブとの重ね合わせ状態での接合によって厚肉となる接合部が、シャフト本体の大径部分の端部よりも変化部が位置する小径部分側に位置していることにより、接合部の厚肉化に起因する医療用シャフトの大径化が問題になり難い。 In addition, the joint, which becomes thicker when the small diameter heat shrink tube and the large diameter heat shrink tube are joined together in an overlapping state, is located on the small diameter side where the transition is located, rather than on the end of the large diameter part of the shaft body, so the increase in diameter of the medical shaft caused by the thickening of the joint is less likely to be a problem.
　第５の態様は、第４の態様に記載された医療用シャフトにおいて、前記シャフト本体における前記変化部が、前記小径部分と前記大径部分との間において外径寸法が長さ方向に変化するテーパ状部分を有しており、前記小径側熱収縮チューブと前記大径側熱収縮チューブとが、該シャフト本体の該テーパ状部分を覆う部位において相互に重ね合わされて接合されているものである。 The fifth aspect is the medical shaft described in the fourth aspect, in which the transition section in the shaft body has a tapered section in which the outer diameter dimension changes in the longitudinal direction between the small diameter section and the large diameter section, and the small diameter side heat shrink tube and the large diameter side heat shrink tube are overlapped and joined to each other at a portion of the shaft body that covers the tapered section.
　本態様に従う構造とされた医療用シャフトによれば、第２の態様と同様に、樹脂チューブにおいてテーパ状部分を覆う部位の外径寸法の変化が比較的緩やかとされると共に、小径側熱収縮チューブと大径側熱収縮チューブとの接合位置（接合部の形成位置）における過度な大径化が抑制され得る。 In a medical shaft constructed according to this embodiment, as in the second embodiment, the change in the outer diameter of the resin tube at the portion covering the tapered portion is relatively gradual, and excessive enlargement of the diameter at the joint position (the position where the joint is formed) between the small diameter side heat shrink tube and the large diameter side heat shrink tube can be suppressed.
　第６の態様は、第４の態様に記載された医療用シャフトにおいて、前記シャフト本体における前記変化部が、前記小径部分と前記大径部分との間において外径寸法が段差状に変化する段差状部分を有しており、前記小径側熱収縮チューブと前記大径側熱収縮チューブとが、該シャフト本体における該小径部分の該段差状部分側の端部を覆う部位において相互に重ね合わされて接合されているものである。 The sixth aspect is a medical shaft as described in the fourth aspect, in which the transition portion in the shaft body has a stepped portion where the outer diameter dimension changes in a stepped manner between the small diameter portion and the large diameter portion, and the small diameter side heat shrink tube and the large diameter side heat shrink tube are overlapped and joined to each other at a portion covering the end of the small diameter portion of the shaft body on the stepped portion side.
　本態様に従う構造とされた医療用シャフトによれば、第３の態様と同様に、樹脂チューブの外周面において小径側熱収縮チューブと大径側熱収縮チューブとが長さ方向で比較的緩やかにつながった湾曲形状をもって接続され得て、シャフト本体の段差状部分における急な外径変化が解消され得る。 In a medical shaft constructed according to this embodiment, as in the third embodiment, the small diameter heat shrink tube and the large diameter heat shrink tube can be connected on the outer circumferential surface of the resin tube in a curved shape that is connected relatively gently in the length direction, eliminating abrupt changes in outer diameter in the stepped portion of the shaft body.
　第７の態様は、第３又は第６の態様に記載された医療用シャフトにおいて、前記シャフト本体における前記大径部分の前記段差状部分側の端部の外周角部が、面取り形状とされているものである。 The seventh aspect is a medical shaft according to the third or sixth aspect, in which the outer circumferential corner of the end of the large diameter portion of the shaft body on the stepped portion side is chamfered.
　本態様に従う構造とされた医療用シャフトによれば、大径部分における段差状部分側の端部の外周角部が面取り形状とされることで、樹脂チューブにおける当該外周角部を覆う部分の厚さ寸法を容易に且つ安定して確保することができて、樹脂チューブの外装加工なども容易とされ得る。 In a medical shaft constructed according to this embodiment, the outer corners of the end of the large diameter portion on the stepped portion side are chamfered, so that the thickness dimension of the portion of the plastic tube that covers the outer corners can be easily and stably ensured, and exterior processing of the plastic tube can also be easily performed.
　第８の態様は、第３又は第６の態様に記載された医療用シャフトにおいて、前記シャフト本体における前記小径部分の前記段差状部分側の端部には、前記大径部分よりも外径寸法の小さい中間リングが外挿状態で取り付けられており、該中間リングを含めて該シャフト本体が前記樹脂チューブで被覆されているものである。 The eighth aspect is a medical shaft according to the third or sixth aspect, in which an intermediate ring having an outer diameter smaller than that of the large diameter portion is attached in an externally inserted state to the end of the small diameter portion of the shaft body on the stepped portion side, and the shaft body including the intermediate ring is covered with the resin tube.
　本態様に従う構造とされた医療用シャフトによれば、中間リングを設けることで、小径部分における外径寸法と大径部分における外径寸法との変化を段階的なものとすることができて、段差の大きさを分散させて実質的に小さくすることが可能になる。それ故、小径部分と大径部分との間を覆う樹脂チューブにおいても、外径寸法が一度に大きく変化することが回避される。従って、例えば小径部分と大径部分との外径寸法差が比較的大きい場合にも、長さ方向において中間リングを挟んで小径部分と大径部分との間にまたがって樹脂チューブが設けられることで、小径側熱収縮チューブと大径側熱収縮チューブとを比較的緩やかに傾斜した外周面をもって接続することができる。 In a medical shaft constructed according to this embodiment, the provision of an intermediate ring allows the change in outer diameter dimension in the small diameter portion and the large diameter portion to be gradual, dispersing the size of the step and making it substantially smaller. Therefore, even in the resin tube that covers the area between the small diameter portion and the large diameter portion, a large change in outer diameter dimension at once is avoided. Therefore, even if the difference in outer diameter dimension between the small diameter portion and the large diameter portion is relatively large, for example, by providing a resin tube that spans between the small diameter portion and the large diameter portion in the length direction across the intermediate ring, the small diameter side heat shrink tube and the large diameter side heat shrink tube can be connected with an outer circumferential surface that is relatively gently inclined.
　第９の態様は、第１～第８の何れか１つの態様に記載された医療用シャフトにおいて、前記樹脂チューブは、前記シャフト本体に対して、接着剤を用いないで重ね合わせ状態で固定されているものである。 The ninth aspect is a medical shaft according to any one of the first to eighth aspects, in which the resin tube is fixed to the shaft body in an overlapping state without using adhesive.
　本態様に従う構造とされた医療用シャフトによれば、樹脂チューブがシャフト本体に対して接着剤を用いないで嵌着固定されていることにより、生体組織に悪影響を及ぼし得る接着剤の使用を回避しながら、樹脂チューブをシャフト本体に対して有効に位置決めすることができる。 In a medical shaft constructed according to this embodiment, the plastic tube is fitted and fixed to the shaft body without the use of adhesives, making it possible to effectively position the plastic tube relative to the shaft body while avoiding the use of adhesives that can have adverse effects on biological tissue.
　第１０の態様は、第１～第９の何れか１つの態様に記載された医療用シャフトにおいて、前記シャフト本体が金属製とされているものである。 The tenth aspect is a medical shaft according to any one of the first to ninth aspects, in which the shaft body is made of metal.
　本態様に従う構造とされた医療用シャフトによれば、シャフト本体が樹脂チューブによって被覆されることにより、硬い金属製とされたシャフト本体の生体組織やダイレータ等への直接的な接触を柔軟な樹脂チューブによって防ぐことができる。また、シャフト本体が金属製とされていることによって、シャフト本体の基端側から先端側へ電気や熱を伝達させ易く、その場合には、例えば、樹脂チューブによってシャフト本体の表面に電気や熱の絶縁層を構成することもできる。 In a medical shaft constructed according to this embodiment, the shaft body is covered with a resin tube, and the flexible resin tube prevents the hard metal shaft body from coming into direct contact with biological tissue, a dilator, etc. In addition, because the shaft body is made of metal, electricity and heat can be easily transferred from the base end to the tip end of the shaft body, and in such cases, for example, an electrical or thermal insulating layer can be formed on the surface of the shaft body using the resin tube.
　第１１の態様は、第１０の態様に記載された医療用シャフトにおいて、前記シャフト本体の表面に粗面化加工が施されているものである。 The eleventh aspect is the medical shaft described in the tenth aspect, in which the surface of the shaft body is roughened.
　本態様に従う構造とされた医療用シャフトによれば、金属製のシャフト本体の表面が粗面化されることにより、樹脂チューブがシャフト本体に対して軸方向で位置決めされ易くなって、樹脂チューブのずれが防止される。 In a medical shaft constructed according to this embodiment, the surface of the metal shaft body is roughened, making it easier to position the plastic tube in the axial direction relative to the shaft body and preventing the plastic tube from shifting.
　第１２の態様は、第２又は第５の態様に記載された医療用シャフトにおいて、前記樹脂チューブの厚さ寸法が、前記シャフト本体における前記小径部分及び前記大径部分を覆う部位において０．０３～０．５０ｍｍの範囲内であり、且つ、前記テーパ状部分を覆う接合部における最大の厚さ寸法が１．００ｍｍ以下とされているものである。 The twelfth aspect is a medical shaft according to the second or fifth aspect, in which the thickness dimension of the resin tube is within the range of 0.03 to 0.50 mm at the portion covering the small diameter portion and the large diameter portion of the shaft body, and the maximum thickness dimension at the joint covering the tapered portion is 1.00 mm or less.
　本態様に従う構造とされた医療用シャフトによれば、過度な大径化を防ぎながら、シャフト本体を樹脂チューブで被覆することによって発揮される緩衝性、絶縁性、耐久性等の目的とする各種性能を有効に得ることができる。 A medical shaft constructed according to this embodiment can effectively achieve the various desired properties, such as cushioning, insulation, and durability, achieved by covering the shaft body with a resin tube, while preventing excessive increase in diameter.
　第１３の態様は、第１～第１２の何れか１つの態様に記載された医療用シャフトにおいて、前記シャフト本体における前記小径部分と前記大径部分との半径寸法の差が０．１～０．８ｍｍの範囲内とされているものである。 The thirteenth aspect is a medical shaft according to any one of the first to twelfth aspects, in which the difference in radial dimension between the small diameter portion and the large diameter portion of the shaft body is within the range of 0.1 to 0.8 mm.
　本態様に従う構造とされた医療用シャフトによれば、シャフト本体において、１つのチューブでは被覆が難しい程度に小径部分と大径部分の半径寸法の差が大きく、且つ、接合部が過度に厚肉になったり、接合部の形状が歪になったりするのを防ぎ得る程度に小径部分と大径部分の半径寸法の差が抑えられている。それゆえ、小径側熱収縮チューブと大径側熱収縮チューブとの接合構造体とされた樹脂チューブを採用することで、シャフト本体を樹脂チューブによって有効に被覆することができる。 In a medical shaft constructed according to this embodiment, the difference in radius between the small diameter portion and the large diameter portion of the shaft body is so large that it is difficult to cover them with a single tube, and the difference in radius between the small diameter portion and the large diameter portion is suppressed to a degree that can prevent the joint from becoming excessively thick or the shape of the joint from becoming distorted. Therefore, by using a resin tube that serves as a joint structure between a small diameter side heat shrink tube and a large diameter side heat shrink tube, the shaft body can be effectively covered by the resin tube.
　第１４の態様は、第１～第１３の何れか１つの態様に記載された医療用シャフトにおいて、前記樹脂チューブの前記接合部において、前記小径側熱収縮チューブと前記大径側熱収縮チューブとが互いに融合して一体化されているものである。 The fourteenth aspect is a medical shaft according to any one of the first to thirteenth aspects, in which the small diameter side heat shrink tube and the large diameter side heat shrink tube are fused together and integrated at the joint of the resin tube.
　本態様に従う構造とされた医療用シャフトによれば、小径側熱収縮チューブと大径側熱収縮チューブが接合部で融合して一体化されていることによって、接合部に集中的な応力が生じても小径側熱収縮チューブと大径側熱収縮チューブの分離が生じ難い。例えば、大径側熱収縮チューブがダイレータ等に対して摺接しながら先端側へ挿入される場合には、変化部を被覆する接合部に対して引張応力が集中的に生じ易いが、このような引張応力の集中的な作用時にも、小径側熱収縮チューブと大径側熱収縮チューブが分離するのを防ぐことができる。 In a medical shaft constructed according to this embodiment, the small diameter heat shrink tube and the large diameter heat shrink tube are fused and integrated at the joint, so that the small diameter heat shrink tube and the large diameter heat shrink tube are unlikely to separate even if concentrated stress occurs at the joint. For example, when the large diameter heat shrink tube is inserted toward the tip while sliding against a dilator or the like, concentrated tensile stress is likely to occur at the joint covering the change section, but even when such concentrated tensile stress acts, it is possible to prevent the small diameter heat shrink tube and the large diameter heat shrink tube from separating.
　第１５の態様は、第１～第１４の何れか１つの態様に記載された医療用シャフトにおいて、前記小径側熱収縮チューブと前記大径側熱収縮チューブとが同一の材質とされているものである。 The fifteenth aspect is a medical shaft according to any one of the first to fourteenth aspects, in which the small diameter side heat shrink tube and the large diameter side heat shrink tube are made of the same material.
　本態様に従う構造とされた医療用シャフトによれば、小径側熱収縮チューブと大径側熱収縮チューブを接合部において融合一体化させ易く、接合部における接合強度を大きく得易くなる。また、小径側熱収縮チューブと大径側熱収縮チューブとが異なる材質とされている場合に比して、樹脂チューブの全長にわたって目的とする性能を実現し易くなる。 With a medical shaft constructed according to this embodiment, the small diameter heat shrink tube and the large diameter heat shrink tube can be easily fused together at the joint, making it easier to obtain high joint strength at the joint. Also, compared to when the small diameter heat shrink tube and the large diameter heat shrink tube are made of different materials, it is easier to achieve the desired performance over the entire length of the resin tube.
　第１６の態様は、動物への施術に際して体内に差し入れられる医療用シャフトの製造方法であって、長さ方向で外径寸法が異ならされて小径部分と大径部分とを有していると共に、該小径部分と該大径部分との間に外径寸法が変化する変化部を有しているシャフト本体を準備する工程と、小径側熱収縮チューブを該シャフト本体の該小径部分に外挿し、且つ、大径側熱収縮チューブを該シャフト本体の該大径部分に外挿すると共に、該大径側熱収縮チューブを該シャフト本体の該大径部分から前記変化部側に延び出させて該シャフト本体の該大径部分よりも該変化部側において該小径側熱収縮チューブにオーバーラップさせて配置する工程と、該シャフト本体に外挿された該小径側熱収縮チューブと該大径側熱収縮チューブとのオーバーラップ部分の外周を成形用熱収縮チューブで覆う工程と、該成形用熱収縮チューブを加熱処理によって熱収縮させて該小径側熱収縮チューブと該大径側熱収縮チューブの該オーバーラップ部分の外周面に当接させることで該オーバーラップ部分の形状を保持させながら、該小径側熱収縮チューブと該大径側熱収縮チューブとを加熱処理によって熱収縮させて該シャフト本体に密着させる工程と、該加熱処理の終了後に該成形用熱収縮チューブを取り除く工程とを、含むものである。 The sixteenth aspect is a method for manufacturing a medical shaft that is inserted into the body of an animal during treatment, comprising the steps of: preparing a shaft body having a small diameter portion and a large diameter portion with different outer diameter dimensions in the length direction, and having a transition portion between the small diameter portion and the large diameter portion, where the outer diameter dimension changes; extrapolating a small diameter side heat shrink tube to the small diameter portion of the shaft body, and extrapolating a large diameter side heat shrink tube to the large diameter portion of the shaft body, and extending the large diameter side heat shrink tube from the large diameter portion of the shaft body toward the transition portion, and attaching the small diameter side heat shrink tube to the small diameter side heat shrink tube on the transition portion side of the large diameter portion of the shaft body; The method includes a step of placing the small diameter heat shrink tube in a burlap manner, a step of covering the outer periphery of the overlapping portion of the small diameter heat shrink tube and the large diameter heat shrink tube that are fitted onto the shaft body with a molding heat shrink tube, a step of heat shrinking the molding heat shrink tube by a heat treatment to bring the tube into contact with the outer periphery of the overlapping portion of the small diameter heat shrink tube and the large diameter heat shrink tube, thereby maintaining the shape of the overlapping portion, and a step of heat shrinking the small diameter heat shrink tube and the large diameter heat shrink tube by a heat treatment to bring them into close contact with the shaft body, and a step of removing the molding heat shrink tube after the heat treatment is completed.
　本態様に従う医療用シャフトの製造方法によれば、小径部分と大径部分が変化部で連結されて長さ方向で外径寸法が変化しているシャフト本体を、樹脂チューブで被覆する際に、小径側熱収縮チューブと大径側熱収縮チューブとを、大径部分よりも変化部側でオーバーラップさせた状態でシャフト本体に外挿配置し、加熱処理によって熱収縮させる。これにより、シャフト本体の小径部分と大径部分の両方が、樹脂チューブによって隙間なく且つ過度に厚肉となることなく被覆される。 In the manufacturing method of medical shafts according to this embodiment, when covering a shaft body in which the small diameter portion and the large diameter portion are connected by a transition portion and the outer diameter dimension changes in the length direction with a resin tube, the small diameter heat shrink tube and the large diameter heat shrink tube are placed on the shaft body in a state where they overlap on the transition portion side of the large diameter portion, and are thermally shrunk by a heat treatment. In this way, both the small diameter portion and the large diameter portion of the shaft body are covered with the resin tube without any gaps and without becoming excessively thick.
　また、小径側熱収縮チューブと大径側熱収縮チューブのオーバーラップ部分は、成形用熱収縮チューブで覆われた状態で、成形用熱収縮チューブと共に加熱処理されて、収縮した成形用熱収縮チューブが小径側熱収縮チューブと大径側熱収縮チューブのオーバーラップ部分に密着する。これにより、小径側熱収縮チューブと大径側熱収縮チューブのオーバーラップ部分の外周面が成形用熱収縮チューブによって成形されて歪な形状になり難い。 In addition, the overlapping portion of the small diameter heat shrink tube and the large diameter heat shrink tube is heated together with the molding heat shrink tube while covered with the molding heat shrink tube, and the shrunk molding heat shrink tube adheres closely to the overlapping portion of the small diameter heat shrink tube and the large diameter heat shrink tube. As a result, the outer periphery of the overlapping portion of the small diameter heat shrink tube and the large diameter heat shrink tube is shaped by the molding heat shrink tube, making it less likely to become distorted.
　第１７の態様は、第１６の態様に記載された医療用シャフトの製造方法において、前記シャフト本体における前記変化部が、前記小径部分と前記大径部分との間において外径寸法が長さ方向で変化するテーパ状部分を有しており、前記加熱処理に際して、前記小径側熱収縮チューブと前記大径側熱収縮チューブとを該シャフト本体の該テーパ状部分で相互にオーバーラップさせて配置するものである。 The seventeenth aspect is the method for manufacturing a medical shaft described in the sixteenth aspect, in which the transition portion in the shaft body has a tapered portion in which the outer diameter dimension changes in the length direction between the small diameter portion and the large diameter portion, and during the heat treatment, the small diameter side heat shrink tube and the large diameter side heat shrink tube are arranged so as to overlap each other at the tapered portion of the shaft body.
　本態様に従う医療用シャフトの製造方法によれば、小径側熱収縮チューブと大径側熱収縮チューブとをテーパ状部分で相互にオーバーラップさせて配置することから、成形用熱収縮チューブを加熱処理によって熱収縮させることで、小径側熱収縮チューブと大径側熱収縮チューブとのオーバーラップ部分をシャフト本体におけるテーパ状部分に対して安定して密着させることができる。 In the manufacturing method for medical shafts according to this embodiment, the small diameter side heat shrink tube and the large diameter side heat shrink tube are arranged so that they overlap each other at the tapered portion, and by thermally shrinking the molding heat shrink tube by heating treatment, the overlapping portion of the small diameter side heat shrink tube and the large diameter side heat shrink tube can be stably and closely attached to the tapered portion of the shaft body.
　第１８の態様は、第１６の態様に記載された医療用シャフトの製造方法において、前記シャフト本体における前記変化部が、前記小径部分と前記大径部分との間において外径寸法が段差状に変化する段差状部分を有しており、前記加熱処理に際して、前記大径側熱収縮チューブを該シャフト本体の該大径部分から該段差状部分を越えて延び出させて該小径部分において前記小径側熱収縮チューブにオーバーラップさせて配置するものである。 The eighteenth aspect is a method for manufacturing a medical shaft as described in the sixteenth aspect, in which the transition portion in the shaft body has a stepped portion in which the outer diameter dimension changes in a stepped manner between the small diameter portion and the large diameter portion, and during the heat treatment, the large diameter side heat shrink tube is extended beyond the stepped portion from the large diameter portion of the shaft body and is positioned so as to overlap the small diameter side heat shrink tube in the small diameter portion.
　本態様に従う医療用シャフトの製造方法によれば、大径側熱収縮チューブを大径部分から段差状部分を越えて延び出させて小径部分において小径側熱収縮チューブにオーバーラップさせて配置することから、成形用熱収縮チューブを加熱処理によって熱収縮させることで、小径側熱収縮チューブと大径側熱収縮チューブのオーバーラップ部分をシャフト本体における小径部分の段差状部分側の端部に対して安定して密着させることができる。 In the manufacturing method for medical shafts according to this embodiment, the large diameter side heat shrink tube extends beyond the step-like portion from the large diameter portion and is positioned so as to overlap the small diameter side heat shrink tube in the small diameter portion. By thermally shrinking the molding heat shrink tube by heating, the overlapping portion of the small diameter side heat shrink tube and the large diameter side heat shrink tube can be stably and closely attached to the end of the small diameter portion of the shaft body on the step-like portion side.
　第１９の態様は、第１６～第１８の何れか１つの態様に記載された医療用シャフトの製造方法において、前記小径側熱収縮チューブと前記大径側熱収縮チューブが前記加熱処理によって相互に溶融する材質とされており、前記成形用熱収縮チューブは該小径側熱収縮チューブと該大径側熱収縮チューブに対して前記加熱処理によって溶融しない材質とされているものである。 The 19th aspect is a method for manufacturing a medical shaft according to any one of the 16th to 18th aspects, in which the small diameter side heat shrink tube and the large diameter side heat shrink tube are made of materials that melt with each other by the heat treatment, and the molding heat shrink tube is made of a material that does not melt with respect to the small diameter side heat shrink tube and the large diameter side heat shrink tube by the heat treatment.
　本態様に従う医療用シャフトの製造方法によれば、加熱処理された小径側熱収縮チューブと大径側熱収縮チューブが相互に溶融して樹脂チューブを一体的に構成することから、シャフト本体が樹脂チューブによって滑らかに被覆される。また、成形用熱収縮チューブが小径側熱収縮チューブと大径側熱収縮チューブとに対して溶融しないことによって、加熱処理の終了後に成形用熱収縮チューブを容易に取り除くことができる。 In the manufacturing method for medical shafts according to this embodiment, the heat-treated small-diameter heat-shrinkable tube and the large-diameter heat-shrinkable tube melt together to form an integrated resin tube, so that the shaft body is smoothly covered with the resin tube. In addition, because the molding heat-shrinkable tube does not melt relative to the small-diameter heat-shrinkable tube and the large-diameter heat-shrinkable tube, the molding heat-shrinkable tube can be easily removed after the heating process is completed.
　第２０の態様は、第１７の態様に記載された医療用シャフトの製造方法において、前記シャフト本体の前記テーパ状部分の傾斜角度が３～６０度の範囲内とされているものである。 The twentieth aspect is the method for manufacturing a medical shaft described in the seventeenth aspect, in which the inclination angle of the tapered portion of the shaft body is within the range of 3 to 60 degrees.
　本態様に従う医療用シャフトの製造方法によれば、テーパ状部分の傾斜角度が３度以上に大きい場合であっても、成形用熱収縮チューブを用いたことによって、テーパ状部分を被覆する小径側及び大径側の熱収縮チューブが加熱処理によって歪な形状となるのを防ぐことができる。テーパ状部分の傾斜角度が６０度以下とされていることによって、テーパ状部分を含むシャフト本体の全体を小径側熱収縮チューブと大径側熱収縮チューブとを用いて被覆することができる。 In the manufacturing method for medical shafts according to this embodiment, even if the inclination angle of the tapered portion is 3 degrees or more, the use of molding heat shrink tubing makes it possible to prevent the small-diameter and large-diameter heat shrink tubing covering the tapered portion from becoming distorted by heat treatment. By making the inclination angle of the tapered portion 60 degrees or less, the entire shaft body including the tapered portion can be covered with the small-diameter heat shrink tubing and the large-diameter heat shrink tubing.
　第２１の態様は、第１６～第２０の何れか１つの態様に記載された医療用シャフトの製造方法において、前記成形用熱収縮チューブは、前記シャフト本体の長さ方向において該シャフト本体の前記変化部から前記小径部分と前記大径部分とにそれぞれ延び出しているものである。 The 21st aspect is a method for manufacturing a medical shaft according to any one of the 16th to 20th aspects, in which the molding heat shrink tube extends from the transition portion of the shaft body to the small diameter portion and the large diameter portion in the longitudinal direction of the shaft body.
　本態様に従う医療用シャフトの製造方法によれば、小径側熱収縮チューブと大径側熱収縮チューブのオーバーラップ部分の全体を成形用熱収縮チューブで覆うことも可能であり、オーバーラップ部分の全体にわたって形状の安定化を図ることもできる。 With this method of manufacturing a medical shaft, it is possible to cover the entire overlapping portion between the small diameter heat shrink tube and the large diameter heat shrink tube with a molding heat shrink tube, and it is also possible to stabilize the shape of the entire overlapping portion.
　第２２の態様は、第１６～第２１の何れか１つの態様に記載された医療用シャフトの製造方法において、前記小径側熱収縮チューブと該大径側熱収縮チューブは、前記シャフト本体の外周面に対して全長にわたって接着又は溶着されることなく重ね合わせ状態で固定されているものである。 The 22nd aspect is a method for manufacturing a medical shaft according to any one of the 16th to 21st aspects, in which the small diameter side heat shrink tube and the large diameter side heat shrink tube are fixed in an overlapping state without being glued or welded to the outer circumferential surface of the shaft body over their entire length.
　本態様に従う医療用シャフトの製造方法によれば、小径側熱収縮チューブと大径側熱収縮チューブとが、何れもシャフト本体の外周面に対して、接着等されることなく嵌合によって固定されている。これにより、接着剤の使用による人体への悪影響が回避されると共に、溶着によるシャフト本体への悪影響等も回避できる。 In the manufacturing method of the medical shaft according to this embodiment, the small diameter heat shrink tube and the large diameter heat shrink tube are both fixed to the outer circumferential surface of the shaft body by fitting without being glued or the like. This avoids the adverse effects on the human body caused by the use of adhesives, and also avoids the adverse effects on the shaft body caused by welding.
　本発明によれば、医療用シャフトにおいて、シャフト本体における小径部分から変化部を経て大径部分に至る領域を、シャフト本体に対して位置固定に設けられた樹脂チューブによって、大径化による問題の発生を抑えながら被覆することができる。 According to the present invention, in a medical shaft, the area of the shaft body that extends from the small diameter portion through the transition portion to the large diameter portion can be covered with a resin tube that is fixed in position relative to the shaft body, while preventing problems caused by the large diameter.
本発明の第１実施形態としての医療用シャフトを示す断面図FIG. 1 is a cross-sectional view showing a medical shaft according to a first embodiment of the present invention. 図１に示す医療用シャフトの製造工程を示す図であって、１次加熱処理前の状態を示す図FIG. 2 is a diagram showing the manufacturing process of the medical shaft shown in FIG. 1, illustrating the state before the first heat treatment. 図１に示す医療用シャフトの製造工程を示す図であって、１次加熱処理の完了後で２次加熱処理前の状態を示す図FIG. 2 is a diagram showing the manufacturing process of the medical shaft shown in FIG. 1, illustrating the state after the completion of the first heating process and before the second heating process. 図１に示す医療用シャフトの製造工程を示す図であって、２次加熱処理の完了状態を示す図FIG. 2 is a diagram showing the manufacturing process of the medical shaft shown in FIG. 1, illustrating the completion state of the secondary heating treatment. 本発明の第２実施形態としての医療用シャフトを示す断面図FIG. 3 is a cross-sectional view showing a medical shaft according to a second embodiment of the present invention. 図３に示す医療用シャフトの製造工程を示す図であって、１次加熱処理前の状態を示す図FIG. 4 is a diagram showing the manufacturing process of the medical shaft shown in FIG. 3, illustrating the state before the first heat treatment. 図３に示す医療用シャフトの製造工程を示す図であって、１次加熱処理完了後で２次加熱処理前の状態を示す図FIG. 4 is a diagram showing the manufacturing process of the medical shaft shown in FIG. 3, illustrating the state after the first heating process and before the second heating process. 図３に示す医療用シャフトの製造工程を示す図であって、２次加熱処理の完了状態を示す図FIG. 4 is a diagram showing the manufacturing process of the medical shaft shown in FIG. 3, illustrating the completed state of the secondary heating treatment. 本発明の第３実施形態としての医療用シャフトを示す断面図FIG. 11 is a cross-sectional view showing a medical shaft according to a third embodiment of the present invention. 図５に示す医療用シャフトの製造工程を示す図であって、１次加熱処理前の状態を示す図FIG. 6 is a diagram showing the manufacturing process of the medical shaft shown in FIG. 5, illustrating the state before the first heat treatment. 図５に示す医療用シャフトの製造工程を示す図であって、１次加熱処理完了後で２次加熱処理前の状態を示す図FIG. 6 is a diagram showing the manufacturing process of the medical shaft shown in FIG. 5, illustrating the state after the first heating process and before the second heating process. 図５に示す医療用シャフトの製造工程を示す図であって、２次加熱処理の完了状態を示す図FIG. 6 is a diagram showing the manufacturing process of the medical shaft shown in FIG. 5, illustrating the completion state of the secondary heating treatment. 本発明の第４実施形態としての医療用シャフトを示す断面図FIG. 11 is a cross-sectional view showing a medical shaft according to a fourth embodiment of the present invention. 本発明の第５実施形態としての医療用シャフトを示す断面図FIG. 13 is a cross-sectional view showing a medical shaft according to a fifth embodiment of the present invention. 本発明の第６実施形態としての医療用シャフトを示す断面図FIG. 13 is a cross-sectional view showing a medical shaft according to a sixth embodiment of the present invention.
　以下、本発明の実施形態について、図面を参照しつつ説明する。 Below, an embodiment of the present invention will be described with reference to the drawings.
　図１には、本発明に係る医療用シャフトの第１実施形態として、高周波ニードル１０が示されている。高周波ニードル１０は、患者への施術に際して体内に差し入れられる医療用器具であって、例えば、心房中隔の卵円窩の穿孔に用いられる。高周波ニードル１０は、シャフト本体１２の外周面が樹脂チューブ１４で覆われた構造を有している。以下の説明では、使用状態で施術者側となる近位端（図１中の左側）を高周波ニードル１０の基端とし、患者側となる遠位端（図１中の右側）を高周波ニードル１０の先端とする。 FIG. 1 shows a high-frequency needle 10 as a first embodiment of a medical shaft according to the present invention. The high-frequency needle 10 is a medical instrument that is inserted into the body during treatment of a patient, and is used, for example, to perforate the fossa ovalis of the atrial septum. The high-frequency needle 10 has a structure in which the outer surface of the shaft body 12 is covered with a resin tube 14. In the following explanation, the proximal end (left side in FIG. 1) that is on the practitioner side when in use is referred to as the base end of the high-frequency needle 10, and the distal end (right side in FIG. 1) that is on the patient side is referred to as the tip of the high-frequency needle 10.
　シャフト本体１２は、ステンレス鋼等の金属で形成された中空長手状の部材とされており、軸方向に延びるルーメン１６を備えている。シャフト本体１２は、ある程度の可撓性を有していることが望ましく、好適には、例えば施術者が手で力を加える等して湾曲形状に塑性変形させることが可能とされている。シャフト本体１２は、小径パイプ１８と大径パイプ２０とを含んで構成されている。 The shaft body 12 is a hollow, longitudinal member made of a metal such as stainless steel, and has a lumen 16 extending in the axial direction. It is desirable for the shaft body 12 to have a certain degree of flexibility, and it is preferably capable of being plastically deformed into a curved shape, for example, by the practitioner applying force with his or her hand. The shaft body 12 is composed of a small diameter pipe 18 and a large diameter pipe 20.
　小径パイプ１８は、略一定の断面形状で延びており、長さ方向の全長にわたって略一定の内径寸法及び外径寸法を有している。小径パイプ１８の軸方向に貫通する内腔が、シャフト本体１２のルーメン１６を構成している。小径パイプ１８の先端部分には、先端から所定の距離だけ離れた位置で周壁の一部を貫通するサイドホール２２が形成されており、サイドホール２２がルーメン１６に連通されている。 The small diameter pipe 18 extends with a generally constant cross-sectional shape, and has generally constant inner and outer diameter dimensions over its entire length. The inner cavity that penetrates the small diameter pipe 18 in the axial direction forms the lumen 16 of the shaft body 12. At the tip of the small diameter pipe 18, a side hole 22 is formed that penetrates part of the peripheral wall at a position a predetermined distance from the tip, and the side hole 22 is connected to the lumen 16.
　小径パイプ１８の先端には、先端チップ２４が設けられている。本実施形態の先端チップ２４は、穿孔用頭部２６を備えている。穿孔用頭部２６は、小径パイプ１８の遠位端から突出して外部に露出した外周面を有している。そして、穿孔用頭部２６は、外部からのエネルギー供給によって体組織に開存孔を形成する機能を有しており、例えば、供給される高周波エネルギーによって体組織を焼灼して、体組織に開存孔を形成し得る。なお、穿孔用頭部２６を加熱するための電力は、小径パイプ１８を導電体とすることで小径パイプ１８によって供給されるようにしてもよいし、小径パイプ１８の内腔に挿通された電気配線によって供給されるようにしてもよい。また、例えば小径パイプ１８が大径パイプ２０の基端まで達しない場合には、小径パイプ１８と大径パイプ２０とを何れも導電体とすることによって、それら小径パイプ１８と大径パイプ２０とによって穿孔用頭部２６に電力を供給することもできる。 A tip tip 24 is provided at the tip of the small diameter pipe 18. The tip tip 24 in this embodiment is equipped with a drilling head 26. The drilling head 26 has an outer circumferential surface that protrudes from the distal end of the small diameter pipe 18 and is exposed to the outside. The drilling head 26 has a function of forming a patent hole in body tissue by supplying energy from the outside, and can form a patent hole in the body tissue by cauterizing the body tissue with supplied high-frequency energy, for example. The power for heating the drilling head 26 may be supplied by the small diameter pipe 18 by making the small diameter pipe 18 a conductor, or may be supplied by electrical wiring inserted into the inner cavity of the small diameter pipe 18. In addition, for example, when the small diameter pipe 18 does not reach the base end of the large diameter pipe 20, the small diameter pipe 18 and the large diameter pipe 20 can both be conductors, and power can be supplied to the drilling head 26 by the small diameter pipe 18 and the large diameter pipe 20.
　穿孔用頭部２６は、シャフト本体１２よりもＸ線が透過し難い（Ｘ線不透過性が高い）ことが望ましい。本実施形態の穿孔用頭部２６は、Ｘ線透視下での視認性に優れた金、プラチナ、プラチナイリジウム、タングステン、ステンレス等の金属材料によって形成されており、先端マーカーとしての機能も有している。穿孔用頭部２６の表面にＸ線不透過性材料によるコーティングを形成して、Ｘ線透視下での視認性の確保や向上を図ることもできる。 The drilling head 26 is preferably less permeable to X-rays (has high X-ray opacity) than the shaft body 12. The drilling head 26 of this embodiment is made of a metal material such as gold, platinum, platinum iridium, tungsten, or stainless steel, which has excellent visibility under X-ray fluoroscopy, and also functions as a tip marker. A coating of X-ray opaque material can be formed on the surface of the drilling head 26 to ensure or improve visibility under X-ray fluoroscopy.
　穿孔用頭部２６の外周面は、先端へ向けて次第に小径となっている。穿孔用頭部２６の形状は、特に限定されるものではないが、管腔内を移動する際に引っ掛かりが生じ難くなるように、遠位側の表面が角を持たない湾曲面とされていることが望ましく、例えば遠位に向けて凸となる略半楕円回転体状とされており、全体として略ラウンドノーズ（円頭弾）の弾頭形状とされている。 The outer periphery of the drilling head 26 has a gradually smaller diameter toward the tip. The shape of the drilling head 26 is not particularly limited, but it is desirable for the distal surface to be a curved surface without corners so that it is less likely to get caught when moving through the lumen. For example, it is shaped like a roughly semi-elliptical body of revolution that is convex toward the distal end, and the overall shape is roughly that of a round-nosed bullet.
　穿孔用頭部２６には、基端側から軸方向に延びる円筒状の接続部分２８が設けられており、接続部分２８が小径パイプ１８の先端に挿入固着されることで、穿孔用頭部２６が小径パイプ１８の先端に固定的に設けられている。即ち、本実施形態では、先端チップ２４が穿孔用頭部２６と接続部分２８を一体的に備えている。 The drilling head 26 is provided with a cylindrical connection part 28 that extends axially from the base end, and the connection part 28 is inserted and fixed to the tip of the small diameter pipe 18, so that the drilling head 26 is fixedly provided to the tip of the small diameter pipe 18. That is, in this embodiment, the tip tip 24 integrally includes the drilling head 26 and the connection part 28.
　先端チップ２４は、穿孔用頭部２６と接続部分２８との間に亘って中心軸上に連続して延びる貫通孔３０が設けられることで、全体として略円筒形状とされている。貫通孔３０の内径寸法が小径パイプ１８の内径寸法よりも小さくされていると共に、接続部分２８の外径寸法が穿孔用頭部２６の基端の外径寸法よりも小さくされて、シャフト本体１２の内径寸法と略同じとされている。接続部分２８の軸方向長さは、穿孔用頭部２６の軸方向長さよりも長いことが望ましく、それによって、穿孔用頭部２６の小径パイプ１８に対する固定強度の向上が図られて、穿孔用頭部２６から施術者の手に伝わる感触の伝達効率も向上し得る。 The tip tip 24 has a generally cylindrical shape with a through hole 30 extending continuously on the central axis between the drilling head 26 and the connecting portion 28. The inner diameter of the through hole 30 is smaller than the inner diameter of the small diameter pipe 18, and the outer diameter of the connecting portion 28 is smaller than the outer diameter of the base end of the drilling head 26 and is generally the same as the inner diameter of the shaft body 12. It is desirable that the axial length of the connecting portion 28 is longer than the axial length of the drilling head 26, thereby improving the fixing strength of the drilling head 26 to the small diameter pipe 18 and improving the transmission efficiency of the sensation transmitted from the drilling head 26 to the practitioner's hand.
　大径パイプ２０は、外径寸法が小径パイプ１８の外径寸法よりも大きく、且つ内径寸法が小径パイプ１８の外径寸法と略同じか僅かに大きくされている。大径パイプ２０は、先端部分が先端へ向けて外径寸法が徐々に小さくなる先細部３２とされている。大径パイプ２０の内径寸法は全長に亘って略一定とされており、先細部３２が先端へ向けて薄肉となっている。 The large diameter pipe 20 has an outer diameter larger than that of the small diameter pipe 18, and an inner diameter that is approximately the same as or slightly larger than that of the small diameter pipe 18. The large diameter pipe 20 has a tapered portion 32 at its tip, where the outer diameter gradually decreases toward the tip. The inner diameter of the large diameter pipe 20 is approximately constant over its entire length, and the tapered portion 32 becomes thinner toward the tip.
　先端チップ２４が取り付けられた小径パイプ１８が大径パイプ２０に挿入されて、それら小径パイプ１８と大径パイプ２０が相互に固定されることによって、シャフト本体１２が構成されている。シャフト本体１２における小径パイプ１８と大径パイプ２０は、小径パイプ１８が大径パイプ２０の内腔に挿入されて接着剤で接着されていてもよいし、レーザー溶接されていてもよい。例えば、大径パイプ２０の内腔に小径パイプ１８が挿入されて、大径パイプ２０の先端部分が小径パイプ１８にレーザー溶接されることによって、小径パイプ１８と大径パイプ２０とが相互に固定されている。また、小径パイプ１８と大径パイプ２０のレーザー溶接によって、大径パイプ２０の先端部分に先細部３２が形成されている。 The shaft body 12 is formed by inserting the small diameter pipe 18 with the tip 24 attached into the large diameter pipe 20 and fixing the small diameter pipe 18 and the large diameter pipe 20 to each other. The small diameter pipe 18 and the large diameter pipe 20 in the shaft body 12 may be bonded with an adhesive by inserting the small diameter pipe 18 into the inner cavity of the large diameter pipe 20, or may be laser welded. For example, the small diameter pipe 18 is inserted into the inner cavity of the large diameter pipe 20, and the tip of the large diameter pipe 20 is laser welded to the small diameter pipe 18, thereby fixing the small diameter pipe 18 and the large diameter pipe 20 to each other. In addition, a tapered portion 32 is formed at the tip of the large diameter pipe 20 by laser welding the small diameter pipe 18 and the large diameter pipe 20.
　シャフト本体１２は、近位端から遠位端まで貫通するルーメン１６を備えている。シャフト本体１２において、小径パイプ１８の基端は、大径パイプ２０の基端までは達していない。それゆえ、シャフト本体１２のルーメン１６は、小径パイプ１８の内腔と大径パイプ２０の内腔とによって構成されている。このように、小径パイプ１８が大径パイプ２０の基端まで達することなく先端側に配されていることにより、シャフト本体１２が過度に硬くなって湾曲追従性が低下したり、シャフト本体１２におけるルーメン１６の内径が全長に亘って小さくなってしまうのを防ぐことができる。 The shaft body 12 has a lumen 16 that runs from the proximal end to the distal end. In the shaft body 12, the base end of the small diameter pipe 18 does not reach the base end of the large diameter pipe 20. Therefore, the lumen 16 of the shaft body 12 is composed of the inner cavity of the small diameter pipe 18 and the inner cavity of the large diameter pipe 20. In this way, by arranging the small diameter pipe 18 on the tip side without reaching the base end of the large diameter pipe 20, it is possible to prevent the shaft body 12 from becoming excessively hard, which would reduce bending followability, or the inner diameter of the lumen 16 in the shaft body 12 from becoming small over the entire length.
　シャフト本体１２において、小径パイプ１８が大径パイプ２０よりも先端側へ突出している。換言すれば、大径パイプ２０の先端は、小径パイプ１８の先端よりも基端側に位置している。そして、小径パイプ１８で構成されたシャフト本体１２の先端部分が小径部分３４とされており、大径パイプ２０を含んで構成されたシャフト本体１２の基端部分が大径部分３６とされている。 In the shaft body 12, the small diameter pipe 18 protrudes further toward the tip side than the large diameter pipe 20. In other words, the tip of the large diameter pipe 20 is located closer to the base end than the tip of the small diameter pipe 18. The tip portion of the shaft body 12 composed of the small diameter pipe 18 is the small diameter portion 34, and the base portion of the shaft body 12 composed including the large diameter pipe 20 is the large diameter portion 36.
　これら小径部分３４と大径部分３６との間には外径寸法が変化する変化部３７が設けられている。本実施形態では、シャフト本体１２における大径パイプ２０の先細部３２が位置する軸方向の中間部分が先端へ向けて外径寸法が次第に小さくなるテーパ状部分３８とされており、変化部３７がテーパ状部分３８を有している。特に、本実施形態では、小径部分３４と大径部分３６との間の軸方向の全長にわたってテーパ状部分３８が設けられており、変化部３７の全体がテーパ状部分３８により構成されている。従って、シャフト本体１２は、小径パイプ１８で構成された小径部分３４が、大径パイプ２０で構成された大径部分３６よりも外径寸法が小さくされており、それら小径部分３４と大径部分３６とをつなぐようにテーパ状部分３８が間に設けられている。テーパ状部分３８が設けられていることにより、シャフト本体１２の外径寸法は、小径部分３４から大径部分３６へ向けて連続的に大きくなっている。なお、小径パイプ１８のサイドホール２２は、大径パイプ２０よりも先端側に位置しており、大径パイプ２０によって覆われていない。 Between the small diameter portion 34 and the large diameter portion 36, there is a transition portion 37 in which the outer diameter dimension changes. In this embodiment, the axial intermediate portion where the tapered portion 32 of the large diameter pipe 20 in the shaft body 12 is located is a tapered portion 38 in which the outer diameter dimension gradually decreases toward the tip, and the transition portion 37 has a tapered portion 38. In particular, in this embodiment, the tapered portion 38 is provided over the entire axial length between the small diameter portion 34 and the large diameter portion 36, and the entire transition portion 37 is composed of the tapered portion 38. Therefore, in the shaft body 12, the small diameter portion 34 formed by the small diameter pipe 18 has a smaller outer diameter dimension than the large diameter portion 36 formed by the large diameter pipe 20, and the tapered portion 38 is provided between the small diameter portion 34 and the large diameter portion 36. Due to the tapered portion 38, the outer diameter dimension of the shaft body 12 is continuously increased from the small diameter portion 34 to the large diameter portion 36. The side hole 22 of the small diameter pipe 18 is located closer to the tip than the large diameter pipe 20 and is not covered by the large diameter pipe 20.
　シャフト本体１２における小径部分３４と大径部分３６との半径寸法の差Δｒは、好適には０．１～０．８ｍｍの範囲内とされ、より好適には０．２～０．３ｍｍの範囲内とされる。なお、本実施形態において、小径部分３４と大径部分３６との半径寸法の差Δｒは、大径パイプ２０の径方向の厚さ寸法によって設定される。 The difference Δr in the radial dimension between the small diameter portion 34 and the large diameter portion 36 in the shaft body 12 is preferably within the range of 0.1 to 0.8 mm, and more preferably within the range of 0.2 to 0.3 mm. In this embodiment, the difference Δr in the radial dimension between the small diameter portion 34 and the large diameter portion 36 is set by the radial thickness dimension of the large diameter pipe 20.
　シャフト本体１２におけるテーパ状部分３８の長さ方向（図１の左右方向）に対する傾斜角度θは、３°≦θ≦６０°とされていることが望ましい。テーパ状部分３８の傾斜角度は、本実施形態では長さ方向の全体にわたって略一定とされている。尤も、テーパ状部分３８の傾斜角度は長さ方向で変化していてもよく、その場合には、傾斜角度の最小値が上記範囲の最小値以上であり、且つ傾斜角度の最大値が上記範囲の最大値以下であることが望ましい。 The inclination angle θ of the tapered portion 38 in the shaft body 12 with respect to the length direction (left-right direction in FIG. 1) is preferably 3°≦θ≦60°. In this embodiment, the inclination angle of the tapered portion 38 is substantially constant throughout the entire length direction. However, the inclination angle of the tapered portion 38 may vary along the length direction, in which case it is preferable that the minimum value of the inclination angle is equal to or greater than the minimum value of the above range, and the maximum value of the inclination angle is equal to or less than the maximum value of the above range.
　シャフト本体１２の外周面は、樹脂チューブ１４によって被覆されている。樹脂チューブ１４は、シャフト本体１２の外周面に嵌合固定されることで、シャフト本体１２に対して位置固定に設けられている。樹脂チューブ１４は、シャフト本体１２の小径部分３４からテーパ状部分３８を経て大径部分３６に至る領域に設けられており、本実施形態では、小径部分３４の先端から大径部分３６の基端に至るシャフト本体１２の略全長にわたって連続して設けられている。先端チップ２４の穿孔用頭部２６は、樹脂チューブ１４で覆われることなく、樹脂チューブ１４よりも先端側へ露出している。 The outer peripheral surface of the shaft body 12 is covered with a resin tube 14. The resin tube 14 is fitted and fixed to the outer peripheral surface of the shaft body 12, thereby being fixed in position relative to the shaft body 12. The resin tube 14 is provided in the area extending from the small diameter portion 34 of the shaft body 12 through the tapered portion 38 to the large diameter portion 36, and in this embodiment, is provided continuously over substantially the entire length of the shaft body 12 from the tip of the small diameter portion 34 to the base end of the large diameter portion 36. The drilling head 26 of the distal tip 24 is not covered by the resin tube 14 and is exposed further distal than the resin tube 14.
　樹脂チューブ１４は、加熱処理によって収縮する熱収縮性を有する樹脂材料で形成される。樹脂チューブ１４の具体的な形成材料は、特に限定されないが、例えば、フッ素化エチレンプロピレン（ＦＥＰ）ポリテトラフルオロエチレン（ＰＴＦＥ）、ポリフッ化ビニリデン（ＰＶＤＦ）等のフッ素樹脂によって形成される。 The resin tube 14 is formed from a resin material having heat shrinkability, which means that the resin tube 14 shrinks when heated. The specific material from which the resin tube 14 is formed is not particularly limited, but it may be formed from a fluororesin such as fluorinated ethylene propylene (FEP), polytetrafluoroethylene (PTFE), or polyvinylidene fluoride (PVDF).
　樹脂チューブ１４は、小径部分３４を覆う第１部位４０と、大径部分３６を覆う第２部位４２とが、略同じ厚さとされている。樹脂チューブ１４は、テーパ状部分３８を覆う第３部位４４が、第１部位４０及び／又は第２部位４２に比して厚肉の接合部４６を有している。本実施形態では、第３部位４４の全体が接合部４６とされている。換言すれば、接合部４６は、シャフト本体１２において大径部分３６の端部よりも変化部３７が位置する小径部分３４側に位置している。第１部位４０及び第２部位４２の厚さ寸法ｔは、電気絶縁性等を考慮して、好適には０．０３～０．５０ｍｍの範囲内とされ、より好適には０．０４～０．０８ｍｍの範囲内とされる。また、第３部位４４の最大厚さ寸法Ｔは、好適には１．００ｍｍ以下とされ、より好適には０．１５ｍｍ以下とされる。なお、樹脂チューブ１４は、小径部分３４を覆う第１部位４０と、大径部分３６を覆う第２部位４２とが、互いに異なる厚さとされていてもよく、その場合に何れが厚肉であってもよい。 The resin tube 14 has a first portion 40 covering the small diameter portion 34 and a second portion 42 covering the large diameter portion 36, which have approximately the same thickness. The resin tube 14 has a third portion 44 covering the tapered portion 38, which has a joint 46 that is thicker than the first portion 40 and/or the second portion 42. In this embodiment, the entire third portion 44 is the joint 46. In other words, the joint 46 is located on the small diameter portion 34 side where the transition portion 37 is located, rather than the end of the large diameter portion 36 in the shaft body 12. The thickness dimension t of the first portion 40 and the second portion 42 is preferably within a range of 0.03 to 0.50 mm, and more preferably within a range of 0.04 to 0.08 mm, taking into account electrical insulation and the like. The maximum thickness dimension T of the third portion 44 is preferably 1.00 mm or less, and more preferably 0.15 mm or less. In addition, the resin tube 14 may have a first portion 40 covering the small diameter portion 34 and a second portion 42 covering the large diameter portion 36 that are different in thickness, in which case either portion may be thicker.
　樹脂チューブ１４は、第１部位４０，第２部位４２，第３部位４４の何れも、シャフト本体１２の外周面に対して、接着剤を用いることなく、重ね合わせ状態で固定されている。本実施形態の樹脂チューブ１４は、シャフト本体１２の外周面に対して、密着状態で嵌着固定されている。樹脂チューブ１４は、後述するように、熱収縮によってシャフト本体１２の外周面に嵌着されている。 The resin tube 14 is fixed in an overlapping state to the outer circumferential surface of the shaft body 12 at the first portion 40, the second portion 42, and the third portion 44 without using adhesive. The resin tube 14 in this embodiment is fitted and fixed in a tight contact state to the outer circumferential surface of the shaft body 12. As described below, the resin tube 14 is fitted to the outer circumferential surface of the shaft body 12 by thermal shrinkage.
　シャフト本体１２の外周面において樹脂チューブ１４が嵌着固定される部分は、粗面化されていることが望ましい。シャフト本体１２の表面の粗面化は、例えば、サンドブラストやショットブラスト等の粗面化加工によって、好適に実現され得る。このような粗面化加工が施されることにより、シャフト本体１２と樹脂チューブ１４との嵌着面の抵抗が大きくなって、樹脂チューブ１４がシャフト本体１２に対して長さ方向でより強固に位置決めされる。 The portion of the outer circumferential surface of the shaft body 12 where the plastic tube 14 is fitted and fixed is preferably roughened. The surface of the shaft body 12 can be suitably roughened by roughening processing such as sand blasting or shot blasting. By carrying out such roughening processing, the resistance of the fitting surface between the shaft body 12 and the plastic tube 14 increases, and the plastic tube 14 is more firmly positioned in the longitudinal direction relative to the shaft body 12.
　ところで、シャフト本体１２の表面が樹脂チューブ１４によって被覆された高周波ニードル１０は、例えば、以下の工程を含む製造方法によって製造することができる。 The high-frequency needle 10, in which the surface of the shaft body 12 is covered with a resin tube 14, can be manufactured, for example, by a manufacturing method including the following steps.
　先ず、小径部分３４と大径部分３６とテーパ状部分３８とを備えたシャフト本体１２を準備する工程を実施する。本実施形態では、引抜加工やプレス加工等によって小径パイプ１８と大径パイプ２０を準備して、小径パイプ１８を大径パイプ２０に嵌め入れることでシャフト本体１２を形成する。大径パイプ２０の先細部３２は、上述したように、例えば、小径パイプ１８へのレーザー溶接時に形成され得る。 First, a process is carried out to prepare the shaft body 12 having a small diameter portion 34, a large diameter portion 36, and a tapered portion 38. In this embodiment, the small diameter pipe 18 and the large diameter pipe 20 are prepared by drawing, pressing, or the like, and the small diameter pipe 18 is fitted into the large diameter pipe 20 to form the shaft body 12. As described above, the tapered portion 32 of the large diameter pipe 20 can be formed, for example, when laser welding to the small diameter pipe 18.
　次に、準備したシャフト本体１２に小径側熱収縮チューブ４８と大径側熱収縮チューブ５０とを外挿する工程を実施する。小径側熱収縮チューブ４８と大径側熱収縮チューブ５０は、何れも加熱によって収縮する熱収縮性を備えた樹脂製のチューブとされており、互いに独立している。本実施形態の小径側熱収縮チューブ４８と大径側熱収縮チューブ５０は、相互に同一の材質とされている。小径側熱収縮チューブ４８と大径側熱収縮チューブ５０は、後述する２次加熱処理によって溶融して相互に融合一体化し得る材質とされていることが望ましい。小径側熱収縮チューブ４８と大径側熱収縮チューブ５０を形成する樹脂材料は、特に限定されないが、例えば、フッ素化エチレンプロピレン（ＦＥＰ）ポリテトラフルオロエチレン（ＰＴＦＥ）、ポリフッ化ビニリデン（ＰＶＤＦ）等のフッ素樹脂によって形成される。 Next, a process is carried out in which the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50 are fitted onto the prepared shaft body 12. The small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50 are both made of resin with heat shrinkability that shrinks when heated, and are independent of each other. In this embodiment, the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50 are made of the same material. It is desirable that the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50 are made of a material that can be melted and fused together by a secondary heating process described later. The resin material forming the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50 is not particularly limited, but is formed of a fluororesin such as fluorinated ethylene propylene (FEP), polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), etc.
　小径側熱収縮チューブ４８の内径寸法は、シャフト本体１２の大径部分３６の外径寸法よりも小さく、且つシャフト本体１２の小径部分３４の外径寸法よりも大きくされており、小径部分３４に対して外挿可能とされている。大径側熱収縮チューブ５０の内径寸法は、シャフト本体１２の大径部分３６の外径寸法よりも大きくされており、大径部分３６に対して外挿可能とされている。このように、小径側熱収縮チューブ４８と大径側熱収縮チューブ５０は、加熱収縮前の直径が相互に異なっており、小径側熱収縮チューブ４８が大径側熱収縮チューブ５０よりも小径とされている。なお、本実施形態の小径側熱収縮チューブ４８と大径側熱収縮チューブ５０は、加熱収縮前の初期形状において略同じ厚さ寸法とされている。 The inner diameter of the small diameter side heat shrink tube 48 is smaller than the outer diameter of the large diameter portion 36 of the shaft body 12 and larger than the outer diameter of the small diameter portion 34 of the shaft body 12, so that it can be fitted around the small diameter portion 34. The inner diameter of the large diameter side heat shrink tube 50 is larger than the outer diameter of the large diameter portion 36 of the shaft body 12, so that it can be fitted around the large diameter portion 36. In this way, the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50 have different diameters before heat shrinking, and the small diameter side heat shrink tube 48 is smaller in diameter than the large diameter side heat shrink tube 50. In this embodiment, the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50 have approximately the same thickness in their initial shapes before heat shrinking.
　小径側熱収縮チューブ４８の厚さ寸法ｔ１は、好適には０．０３～０．５０ｍｍの範囲内とされる。また、大径側熱収縮チューブ５０の厚さ寸法ｔ２は、好適には０．０３～０．５０ｍｍの範囲内とされる。本実施形態において、小径側熱収縮チューブ４８の厚さ寸法ｔ１と大径側熱収縮チューブ５０の厚さ寸法ｔ２は、略同じとされているが、相互に異なっていてもよく、その場合には何れが厚肉であってもよい。 The thickness dimension t1 of the small diameter side heat shrink tube 48 is preferably within the range of 0.03 to 0.50 mm. The thickness dimension t2 of the large diameter side heat shrink tube 50 is preferably within the range of 0.03 to 0.50 mm. In this embodiment, the thickness dimension t1 of the small diameter side heat shrink tube 48 and the thickness dimension t2 of the large diameter side heat shrink tube 50 are approximately the same, but they may be different from each other, in which case either one may be thicker.
　そして、小径側熱収縮チューブ４８をシャフト本体１２の小径部分３４に外挿し、且つ大径側熱収縮チューブ５０をシャフト本体１２の大径部分３６に外挿する。この大径側熱収縮チューブ５０は、シャフト本体１２の大径部分３６から変化部３７（テーパ状部分３８）側に延び出させて、シャフト本体１２の大径部分３６よりも変化部３７側において小径側熱収縮チューブ４８にオーバーラップさせて配置する。具体的には、小径側熱収縮チューブ４８をシャフト本体１２における小径部分３４からテーパ状部分３８の途中に至るまで外挿すると共に、大径側熱収縮チューブ５０をシャフト本体１２における大径部分３６からテーパ状部分３８の途中に至るまで外挿する。 Then, the small diameter side heat shrink tube 48 is fitted onto the small diameter portion 34 of the shaft body 12, and the large diameter side heat shrink tube 50 is fitted onto the large diameter portion 36 of the shaft body 12. This large diameter side heat shrink tube 50 extends from the large diameter portion 36 of the shaft body 12 toward the transition portion 37 (tapered portion 38) side, and is arranged so as to overlap the small diameter side heat shrink tube 48 on the transition portion 37 side of the large diameter portion 36 of the shaft body 12. Specifically, the small diameter side heat shrink tube 48 is fitted onto the shaft body 12 from the small diameter portion 34 to the middle of the tapered portion 38, and the large diameter side heat shrink tube 50 is fitted onto the shaft body 12 from the large diameter portion 36 to the middle of the tapered portion 38.
　図２Ａに示すように、シャフト本体１２に外挿された小径側熱収縮チューブ４８と大径側熱収縮チューブ５０は、テーパ状部分３８の外周において径方向の投影で重なり合うオーバーラップ状態とされる。即ち、小径側熱収縮チューブ４８の基端が大径側熱収縮チューブ５０の先端よりも基端側に位置しており、小径側熱収縮チューブ４８におけるテーパ状部分３８に外挿された基端部が、大径側熱収縮チューブ５０におけるテーパ状部分３８に外挿された先端部の内周へ差し入れられて、オーバーラップ部分５２が設けられている。本実施形態において、小径側熱収縮チューブ４８と大径側熱収縮チューブ５０のオーバーラップ部分５２は、テーパ状部分３８の略全体にわたって連続的に設定されている。 2A, the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50 inserted on the shaft body 12 are in an overlapping state in which they overlap in radial projection on the outer periphery of the tapered portion 38. That is, the base end of the small diameter side heat shrink tube 48 is located on the base end side of the tip end of the large diameter side heat shrink tube 50, and the base end of the small diameter side heat shrink tube 48 inserted on the tapered portion 38 is inserted into the inner periphery of the tip end of the large diameter side heat shrink tube 50 inserted on the tapered portion 38, providing an overlapping portion 52. In this embodiment, the overlapping portion 52 of the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50 is set continuously over almost the entire tapered portion 38.
　次に、小径側熱収縮チューブ４８と大径側熱収縮チューブ５０を加熱によって収縮させる１次加熱処理を行う工程を実施する。例えば、シャフト本体１２に外挿された小径側熱収縮チューブ４８と大径側熱収縮チューブ５０の外周側に加熱装置５４が配されており、加熱装置５４から小径側熱収縮チューブ４８と大径側熱収縮チューブ５０に向けて加熱された空気が吹き付けられる。加熱装置５４は、小径側熱収縮チューブ４８及び大径側熱収縮チューブ５０に向けて加熱空気を吹き付けながら、シャフト本体１２に対して軸方向に相対移動可能とされており、それによって、小径側熱収縮チューブ４８及び大径側熱収縮チューブ５０の全体が加熱されて熱収縮する。 Next, a primary heating process is performed to shrink the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50 by heating. For example, a heating device 54 is disposed on the outer periphery of the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50 that are fitted onto the shaft body 12, and heated air is blown from the heating device 54 toward the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50. The heating device 54 is movable in the axial direction relative to the shaft body 12 while blowing heated air toward the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50, whereby the entire small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50 are heated and thermally shrunk.
　そして、加熱空気によって温められた小径側熱収縮チューブ４８と大径側熱収縮チューブ５０は、熱収縮して小径となることにより、図２Ｂに示すように、シャフト本体１２の表面にそれぞれ接近する。例えば、１次加熱処理によって、小径側熱収縮チューブ４８がシャフト本体１２の小径部分３４に密着すると共に、大径側熱収縮チューブ５０が大径部分３６に密着して、それら小径側熱収縮チューブ４８と大径側熱収縮チューブ５０がシャフト本体１２に対して位置決めされる。小径側熱収縮チューブ４８と大径側熱収縮チューブ５０は、相互に融合することなく独立しており、テーパ状部分３８には密着していなくてもよい。 Then, the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50, which have been warmed by the heated air, are thermally shrunk to a small diameter, and approach the surface of the shaft body 12, as shown in FIG. 2B. For example, the small diameter side heat shrink tube 48 is brought into close contact with the small diameter portion 34 of the shaft body 12, and the large diameter side heat shrink tube 50 is brought into close contact with the large diameter portion 36, by the primary heating process, and the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50 are positioned relative to the shaft body 12. The small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50 are independent and do not fuse with each other, and do not have to be in close contact with the tapered portion 38.
　１次加熱処理の完了後に、図２Ｂに示すように、シャフト本体１２を覆う小径側熱収縮チューブ４８と大径側熱収縮チューブ５０に対して、成形用熱収縮チューブ５６を外挿状態で配置する工程を実施する。 After the primary heat treatment is completed, a process is carried out in which a molding heat shrink tube 56 is placed in an externally inserted state around the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50 that cover the shaft body 12, as shown in FIG. 2B.
　成形用熱収縮チューブ５６は、樹脂製のチューブであって、加熱によって収縮する熱収縮性を備えている。成形用熱収縮チューブ５６は、小径側熱収縮チューブ４８及び大径側熱収縮チューブ５０とは異なる材質とされていることが望ましい。また、成形用熱収縮チューブ５６は、好適には、後述する２次加熱処理の加熱温度で溶融しない材質とされる。これらにより、成形用熱収縮チューブ５６は、後述する２次加熱処理において小径側熱収縮チューブ４８及び大径側熱収縮チューブ５０と融合一体化しない。成形用熱収縮チューブ５６は、小径側熱収縮チューブ４８と大径側熱収縮チューブ５０とに比して、加熱による収縮率が大きい材質が望ましい。成形用熱収縮チューブ５６の形成材料としては、例えば、ポリオレフィンが採用される。成形用熱収縮チューブ５６は、小径側熱収縮チューブ４８及び大径側熱収縮チューブ５０よりも厚肉とされており、熱収縮時の形状安定性が高められている。小径側熱収縮チューブ４８及び大径側熱収縮チューブ５０に外挿された成形用熱収縮チューブ５６は、加熱装置５４によって加熱可能な位置に配置されている。 The molding heat shrink tube 56 is a resin tube that has heat shrinkability, that is, shrinkage caused by heating. The molding heat shrink tube 56 is preferably made of a material different from the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50. The molding heat shrink tube 56 is preferably made of a material that does not melt at the heating temperature of the secondary heating process described below. As a result, the molding heat shrink tube 56 does not fuse and integrate with the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50 in the secondary heating process described below. The molding heat shrink tube 56 is preferably made of a material that has a higher shrinkage rate due to heating than the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50. For example, polyolefin is used as the material for forming the molding heat shrink tube 56. The molding heat shrink tube 56 is made thicker than the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50, and has improved shape stability during heat shrinkage. The molding heat shrink tube 56, which is inserted around the small diameter heat shrink tube 48 and the large diameter heat shrink tube 50, is positioned in a position where it can be heated by the heating device 54.
　成形用熱収縮チューブ５６は、シャフト本体１２のテーパ状部分３８よりも長さ方向において長くされている。そして、成形用熱収縮チューブ５６は、シャフト本体１２のテーパ状部分３８に外挿されていると共に、変化部３７（テーパ状部分３８）よりも先端側（小径部分３４側）と基端側（大径部分３６側）の両側へそれぞれ延び出しており、小径部分３４の基端部と大径部分３６の先端部にも外挿されている。従って、テーパ状部分３８に外挿されたオーバーラップ部分５２の外周の全体が、成形用熱収縮チューブ５６によって覆われている。 The molding heat shrink tube 56 is longer in the longitudinal direction than the tapered portion 38 of the shaft body 12. The molding heat shrink tube 56 is fitted onto the tapered portion 38 of the shaft body 12, and extends beyond the transition portion 37 (tapered portion 38) to both the tip side (small diameter portion 34 side) and the base end side (large diameter portion 36 side), and is also fitted onto the base end of the small diameter portion 34 and the tip end of the large diameter portion 36. Therefore, the entire outer periphery of the overlap portion 52 fitted onto the tapered portion 38 is covered by the molding heat shrink tube 56.
　次に、小径側熱収縮チューブ４８及び大径側熱収縮チューブ５０と成形用熱収縮チューブ５６を加熱装置５４によって１次加熱処理よりも更に高温まで加熱する２次加熱処理を行う工程を実施する。２次加熱処理によって、図２Ｃに示すように、小径側熱収縮チューブ４８と大径側熱収縮チューブ５０のオーバーラップ部分５２が溶融して融合一体化することにより接合部４６が形成されると共に、接合部４６がシャフト本体１２のテーパ状部分３８の表面に密着する。これにより、シャフト本体１２の表面を被覆する樹脂チューブ１４が、一体化した小径側熱収縮チューブ４８と大径側熱収縮チューブ５０とによって構成される。要するに、樹脂チューブ１４は、小径側熱収縮チューブ４８と大径側熱収縮チューブ５０とが接合部４６において融合一体化して接合された接合構造体とされている。なお、２次加熱処理後の小径側熱収縮チューブ４８と大径側熱収縮チューブ５０は、明確な境界を有することなく一体的に樹脂チューブ１４を構成することが望ましいが、例えば、溶融部分の境界が表れていてもよい。 Next, a secondary heating process is performed in which the small diameter side heat shrink tube 48, the large diameter side heat shrink tube 50, and the molding heat shrink tube 56 are heated to a temperature higher than that of the primary heating process by a heating device 54. As a result of the secondary heating process, as shown in FIG. 2C, the overlapping portion 52 of the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50 melts and fuses together to form a joint 46, and the joint 46 adheres closely to the surface of the tapered portion 38 of the shaft body 12. As a result, the resin tube 14 covering the surface of the shaft body 12 is composed of the integrated small diameter side heat shrink tube 48 and large diameter side heat shrink tube 50. In short, the resin tube 14 is a joint structure in which the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50 are fused together and joined at the joint 46. After the secondary heat treatment, it is desirable for the small diameter heat shrink tube 48 and the large diameter heat shrink tube 50 to form the resin tube 14 as a single unit without a clear boundary, but for example, the boundary of the molten portion may be visible.
　熱収縮前の直径が相互に異なる小径側熱収縮チューブ４８と大径側熱収縮チューブ５０を用いて樹脂チューブ１４を形成することにより、シャフト本体１２の小径部分３４と大径部分３６との外径寸法の差に対応して、樹脂チューブ１４を全長にわたってシャフト本体１２の外周面に密着させることができる。従って、樹脂チューブ１４は、全長にわたってシャフト本体１２に嵌着されて、シャフト本体１２の表面を位置固定に被覆する。本実施形態では、シャフト本体１２の表面が粗面化されていることから、樹脂チューブ１４がシャフト本体１２に対して密着することでより強固に位置決めされる。 By forming the resin tube 14 using a small diameter heat shrink tube 48 and a large diameter heat shrink tube 50 that have different diameters before heat shrinking, the resin tube 14 can be tightly attached to the outer circumferential surface of the shaft body 12 over its entire length in accordance with the difference in outer diameter dimension between the small diameter portion 34 and the large diameter portion 36 of the shaft body 12. Therefore, the resin tube 14 is fitted into the shaft body 12 over its entire length, covering the surface of the shaft body 12 and fixing its position. In this embodiment, since the surface of the shaft body 12 is roughened, the resin tube 14 is more firmly positioned by being tightly attached to the shaft body 12.
　樹脂チューブ１４（２次加熱処理後の小径側熱収縮チューブ４８及び大径側熱収縮チューブ５０）は、シャフト本体１２の表面に対して、接着されていないだけでなく溶着もされておらず、嵌合固定されていることが望ましい。これにより、接着剤の使用による患者への悪影響が回避されると共に、小径側熱収縮チューブ４８と大径側熱収縮チューブ５０を内周面まで溶融するほどに加熱することなく、シャフト本体１２に固定することができる。 It is desirable that the resin tube 14 (small diameter side heat shrink tube 48 and large diameter side heat shrink tube 50 after the secondary heating process) is not glued or welded to the surface of the shaft body 12, but is fitted and fixed. This avoids adverse effects on the patient caused by the use of adhesives, and allows the small diameter side heat shrink tube 48 and large diameter side heat shrink tube 50 to be fixed to the shaft body 12 without heating them to the point of melting them all the way to their inner surfaces.
　樹脂チューブ１４の第３部位４４は、オーバーラップして配された小径側熱収縮チューブ４８と大径側熱収縮チューブ５０が融合一体化して形成されることにより、小径側熱収縮チューブ４８単体で構成された第１部位４０及び／又は大径側熱収縮チューブ５０単体で構成された第２部位４２に比して厚肉とされており、第３部位４４の全体が接合部４６とされている。接合部４６は、加熱処理前の小径側熱収縮チューブ４８及び大径側熱収縮チューブ５０の何れかよりも厚さ寸法が大きくされており、本実施形態では、接合部４６の厚さ寸法は、互いに略同じ厚さ寸法とされた小径側熱収縮チューブ４８と大径側熱収縮チューブ５０の何れの厚さ寸法よりも大きくされている。厚肉とされた接合部４６は、シャフト本体１２のテーパ状部分３８の外周面上に位置しており、テーパ状部分３８の表面の全体が接合部４６で覆われている。 The third portion 44 of the resin tube 14 is formed by fusing together the overlapping small-diameter heat-shrinkable tube 48 and large-diameter heat-shrinkable tube 50, and is thicker than the first portion 40 made up of the small-diameter heat-shrinkable tube 48 alone and/or the second portion 42 made up of the large-diameter heat-shrinkable tube 50 alone, and the entire third portion 44 is the joint portion 46. The joint portion 46 is thicker than either the small-diameter heat-shrinkable tube 48 or the large-diameter heat-shrinkable tube 50 before the heat treatment, and in this embodiment, the thickness of the joint portion 46 is thicker than either the small-diameter heat-shrinkable tube 48 or the large-diameter heat-shrinkable tube 50, which have approximately the same thickness. The thick joint portion 46 is located on the outer circumferential surface of the tapered portion 38 of the shaft body 12, and the entire surface of the tapered portion 38 is covered with the joint portion 46.
　樹脂チューブ１４の第１部位４０の厚さ寸法は、熱収縮前の小径側熱収縮チューブ４８の厚さ寸法以下とされている。また、樹脂チューブ１４の第２部位４２の厚さ寸法は、熱収縮前の大径側熱収縮チューブ５０の厚さ寸法以下とされている。更に、樹脂チューブ１４の第３部位４４の厚さ寸法は、熱収縮前の小径側熱収縮チューブ４８と大径側熱収縮チューブ５０の厚さ寸法の合計よりも小さくされている。 The thickness dimension of the first portion 40 of the resin tube 14 is less than or equal to the thickness dimension of the small diameter side heat shrink tube 48 before heat shrinkage. The thickness dimension of the second portion 42 of the resin tube 14 is less than or equal to the thickness dimension of the large diameter side heat shrink tube 50 before heat shrinkage. Furthermore, the thickness dimension of the third portion 44 of the resin tube 14 is less than the sum of the thickness dimensions of the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50 before heat shrinkage.
　また、２次加熱処理によって熱収縮した成形用熱収縮チューブ５６は、図２Ｃに示すように、テーパ状部分３８の表面に密着した小径側熱収縮チューブ４８と大径側熱収縮チューブ５０のオーバーラップ部分５２に対して、外周側から押し当てられる。成形用熱収縮チューブ５６は、変化部３７（テーパ状部分３８）よりも先端側及び基端側まで延び出していることから、テーパ状部分３８に連接された小径部分３４の基端部及び大径部分３６の先端部まで覆うように、テーパ状部分３８の両端を含む領域に密着している。従って、テーパ状部分３８に重ね合わされた小径側熱収縮チューブ４８と大径側熱収縮チューブ５０のオーバーラップ部分５２の全体が、成形用熱収縮チューブ５６の当接によって形状を保持されながら融合一体化して、所定の形状に成形される。このように、２次加熱処理において樹脂チューブ１４の第３部位４４の外周面に押し当てられる成形用熱収縮チューブ５６を採用することで、小径側熱収縮チューブ４８と大径側熱収縮チューブ５０のオーバーラップによって局所的な凸等の歪な形状となり易い樹脂チューブ１４の第３部位４４を、滑らかな表面形状とすることができる。 The molding heat shrink tube 56, which has been heat-shrunk by the secondary heating process, is pressed against the overlapping portion 52 of the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50, which are in close contact with the surface of the tapered portion 38, from the outer periphery, as shown in FIG. 2C. The molding heat shrink tube 56 extends beyond the transition portion 37 (tapered portion 38) to the tip and base ends, and is in close contact with the area including both ends of the tapered portion 38, so as to cover the base end of the small diameter portion 34 connected to the tapered portion 38 and the tip end of the large diameter portion 36. Therefore, the entire overlapping portion 52 of the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50, which are superimposed on the tapered portion 38, are fused and integrated while maintaining their shape by the contact of the molding heat shrink tube 56, and are molded into a predetermined shape. In this way, by using the molding heat shrink tube 56 that is pressed against the outer circumferential surface of the third portion 44 of the resin tube 14 during the secondary heat treatment, the third portion 44 of the resin tube 14, which is prone to becoming distorted, such as locally convex, due to the overlap between the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50, can be given a smooth surface shape.
　２次加熱処理の完了後に、成形用熱収縮チューブ５６を樹脂チューブ１４の表面から取り除く工程を実施する。これにより、シャフト本体１２の表面が樹脂チューブ１４で被覆された高周波ニードル１０を得ることができる。成形用熱収縮チューブ５６は、樹脂チューブ１４を構成する小径側熱収縮チューブ４８及び大径側熱収縮チューブ５０とは異なる材質とされていることにより、２次加熱処理において樹脂チューブ１４と溶融一体化することなく、２次加熱処理後に樹脂チューブ１４から容易に取り外すことができる。成形用熱収縮チューブ５６は、好適には、小径側熱収縮チューブ４８及び大径側熱収縮チューブ５０とは融点が異なる樹脂材料によって形成される。また、成形用熱収縮チューブ５６を樹脂チューブ１４から取り外す工程は、樹脂チューブ１４と成形用熱収縮チューブ５６とを必要に応じて冷却した後に実施することが望ましい。 After the secondary heat treatment is completed, a process is performed to remove the molding heat shrink tube 56 from the surface of the resin tube 14. This makes it possible to obtain a high-frequency needle 10 in which the surface of the shaft body 12 is covered with the resin tube 14. The molding heat shrink tube 56 is made of a material different from the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50 that constitute the resin tube 14, so that it can be easily removed from the resin tube 14 after the secondary heat treatment without being melted and integrated with the resin tube 14 during the secondary heat treatment. The molding heat shrink tube 56 is preferably made of a resin material with a melting point different from that of the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50. In addition, the process of removing the molding heat shrink tube 56 from the resin tube 14 is desirably performed after cooling the resin tube 14 and the molding heat shrink tube 56 as necessary.
　成形用熱収縮チューブ５６は、樹脂チューブ１４の成形後に取り除かれることから、厚さや材質の選択自由度が小径側熱収縮チューブ４８及び大径側熱収縮チューブ５０よりも大きく、例えば加熱収縮時の形状安定性に優れた材質とすることもできる。それゆえ、成形用熱収縮チューブ５６を用いることにより、２次加熱処理において樹脂チューブ１４の第３部位４４の外周面形状を滑らかな所定形状に安定して成形することができる。 Since the molding heat shrink tube 56 is removed after molding the resin tube 14, there is greater freedom in selecting the thickness and material than with the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50, and it can be made of a material that has excellent shape stability during heat shrinking, for example. Therefore, by using the molding heat shrink tube 56, the outer peripheral surface shape of the third portion 44 of the resin tube 14 can be stably molded into a smooth, predetermined shape during the secondary heat treatment.
　このようにして得られた高周波ニードル１０は、例えば、心房中隔の卵円窩の穿孔に用いられる。即ち、右心房に挿入された高周波ニードル１０の穿孔用頭部２６が、右心房と左心房を仕切る心房中隔における卵円孔の閉塞部分（卵円窩）に押し当てられて、高周波電力の供給による穿孔用頭部２６の発熱によって、卵円窩を焼灼して所定の開存孔を形成する。 The high-frequency needle 10 obtained in this manner is used, for example, to perforate the fossa ovalis in the atrial septum. That is, the perforation head 26 of the high-frequency needle 10 inserted into the right atrium is pressed against the blocked portion of the foramen ovale (fossa ovalis) in the atrial septum that separates the right and left atria, and the perforation head 26 generates heat due to the supply of high-frequency power, cauterizing the fossa ovalis and forming a specified patent foramen.
　本実施形態では、シャフト本体１２が導電性の金属で形成されており、シャフト本体１２を介して穿孔用頭部２６に通電される。シャフト本体１２の外周面は、穿孔用頭部２６よりも基端側が略全長にわたって電気絶縁性の樹脂チューブ１４で覆われており、電力エネルギーのロスや感電の危険性が防止されている。 In this embodiment, the shaft body 12 is made of a conductive metal, and electricity is passed through the shaft body 12 to the drilling head 26. The outer circumferential surface of the shaft body 12 is covered over substantially the entire length from the base end side of the drilling head 26 with an electrically insulating resin tube 14, preventing loss of electrical energy and the risk of electric shock.
　また、高周波ニードル１０は、右心房へ挿入された図示しないダイレータに挿入されることで、右心房まで案内される。高周波ニードル１０は、樹脂チューブ１４が厚肉となる接合部４６が、シャフト本体１２のテーパ状部分３８に位置していることから、樹脂チューブ１４の部分的な厚肉化が高周波ニードル１０のダイレータへの挿入に際して問題になり難い。蓋し、接合部４６がテーパ状部分３８に位置していることで、接合部４６が厚肉とされていても高周波ニードル１０の最大外径の大型化につながり難く、また、厚肉の接合部４６が挿入性に影響し易い先端部分を構成しないからである。 The high-frequency needle 10 is guided to the right atrium by being inserted into a dilator (not shown) that is inserted into the right atrium. The high-frequency needle 10 has a joint 46 at which the resin tube 14 becomes thick, located in the tapered portion 38 of the shaft body 12, so that partial thickening of the resin tube 14 is unlikely to be a problem when inserting the high-frequency needle 10 into the dilator. In particular, because the joint 46 is located in the tapered portion 38, even if the joint 46 is made thick, it is unlikely to lead to an increase in the maximum outer diameter of the high-frequency needle 10, and the thick joint 46 does not form a tip portion that is likely to affect insertability.
　しかも、厚肉となる接合部４６は、成形用熱収縮チューブ５６によって局所的な凹凸が抑えられた滑らかな形状に成形されることから、ダイレータへの挿入時の引っ掛かり等も問題となり難い。 In addition, the thick joint 46 is molded into a smooth shape with minimal localized unevenness by the heat shrink tube 56, so there are few problems with it getting caught when inserted into the dilator.
　なお、シャフト本体１２の近位端には、図示しない操作ハンドルが取り付けられていてもよい。操作ハンドルは、施術者が把持して操作するものであって、シャフト本体１２の挿抜、周方向の向き、湾曲変形の程度等を操作することができる。また、操作ハンドルは、シャフト本体１２のルーメン１６を近位へ開放するハブとしての機能を有していてもよい。 In addition, an operating handle (not shown) may be attached to the proximal end of the shaft body 12. The operating handle is held and operated by the practitioner, and can be used to insert and remove the shaft body 12, to control its circumferential orientation, and to control the degree of bending and deformation. The operating handle may also function as a hub that opens the lumen 16 of the shaft body 12 proximally.
　図３には、本発明に係る医療用シャフトの第２実施形態として、高周波ニードル６０が示されている。高周波ニードル６０は、シャフト本体１２の外周面が樹脂チューブ６２で覆われた構造を有している。以下の説明において、第１実施形態と実質的に同一の部材及び部位については、図中に同一の符号を付すことにより説明を省略する。 FIG. 3 shows a high-frequency needle 60 as a second embodiment of a medical shaft according to the present invention. The high-frequency needle 60 has a structure in which the outer circumferential surface of the shaft body 12 is covered with a resin tube 62. In the following explanation, the same reference numerals are used in the figure to denote components and parts that are substantially the same as those in the first embodiment, and explanations thereof will be omitted.
　樹脂チューブ６２は、シャフト本体１２の変化部３７（テーパ状部分３８）を覆う第３部位４４の厚さ寸法が、長さ方向（図３中の左右方向）において変化しており、第３部位４４におけるテーパ状部分３８の先端側を覆う部分が、テーパ状部分３８の基端側を覆う部分よりも厚肉の接合部６４とされている。要するに、本実施形態では、樹脂チューブ６２の第３部位４４が接合部６４を長さ方向で部分的に備えている。また、接合部６４の長さ方向の位置が、第３部位４４の先端側に設定されている。接合部６４の長さ寸法は、好適には、第３部位４４の長さ寸法の半分以下とされ、且つ第３部位４４の長さ寸法の１／４以上とされている。 The resin tube 62 has a third section 44 that covers the transition section 37 (tapered section 38) of the shaft body 12, and the thickness of the third section 44 changes in the longitudinal direction (left-right direction in FIG. 3), and the portion of the third section 44 that covers the tip side of the tapered section 38 is a joint 64 that is thicker than the portion that covers the base end side of the tapered section 38. In short, in this embodiment, the third section 44 of the resin tube 62 is partially provided with the joint 64 in the longitudinal direction. The longitudinal position of the joint 64 is set on the tip side of the third section 44. The length of the joint 64 is preferably less than half the length of the third section 44 and greater than or equal to ¼ of the length of the third section 44.
　本実施形態の高周波ニードル６０は、例えば、図４Ａ～Ｃに示す工程を経て製造することができる。すなわち、本実施形態においても、先ず、小径側熱収縮チューブ４８をシャフト本体１２の小径部分３４に外挿し、且つ大径側熱収縮チューブ５０をシャフト本体１２の大径部分３６に外挿する。そして、大径側熱収縮チューブ５０を、シャフト本体１２の大径部分３６から変化部３７（テーパ状部分３８）側に延び出させて、シャフト本体１２の大径部分３６よりも変化部３７側において小径側熱収縮チューブ４８にオーバーラップさせて配置する。具体的には、図４Ａに示すように、予め準備したシャフト本体１２に対して、小径側熱収縮チューブ４８と大径側熱収縮チューブ５０とを外挿する。小径側熱収縮チューブ４８の基端部は、大径側熱収縮チューブ５０の先端部の内周へ挿入されている。内外挿状態で配された小径側熱収縮チューブ４８と大径側熱収縮チューブ５０のオーバーラップ部分６６は、シャフト本体１２におけるテーパ状部分３８の先端部分の外周側に配されており、テーパ状部分３８の基端部分の外周側には小径側熱収縮チューブ４８が配されていない。 The high-frequency needle 60 of this embodiment can be manufactured, for example, through the steps shown in Figures 4A to 4C. That is, in this embodiment as well, first, the small diameter side heat shrink tube 48 is fitted onto the small diameter portion 34 of the shaft body 12, and the large diameter side heat shrink tube 50 is fitted onto the large diameter portion 36 of the shaft body 12. Then, the large diameter side heat shrink tube 50 is extended from the large diameter portion 36 of the shaft body 12 toward the transition portion 37 (tapered portion 38) side, and is arranged so as to overlap the small diameter side heat shrink tube 48 on the transition portion 37 side of the large diameter portion 36 of the shaft body 12. Specifically, as shown in Figure 4A, the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50 are fitted onto the shaft body 12 prepared in advance. The base end of the small diameter side heat shrink tube 48 is inserted into the inner circumference of the tip portion of the large diameter side heat shrink tube 50. The overlapping portion 66 of the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50, which are arranged in an internally and externally inserted state, is arranged on the outer periphery side of the tip portion of the tapered portion 38 of the shaft body 12, and the small diameter side heat shrink tube 48 is not arranged on the outer periphery side of the base end portion of the tapered portion 38.
　次に、小径側熱収縮チューブ４８と大径側熱収縮チューブ５０を加熱によって収縮させる１次加熱処理を行う工程を実施する。加熱された小径側熱収縮チューブ４８と大径側熱収縮チューブ５０は、熱収縮して小径となることにより、図４Ｂに示すように、シャフト本体１２の表面にそれぞれ接近する。１次加熱処理によって、小径側熱収縮チューブ４８がシャフト本体１２の小径部分３４に密着すると共に、大径側熱収縮チューブ５０が大径部分３６に密着して、それら小径側熱収縮チューブ４８と大径側熱収縮チューブ５０がシャフト本体１２に対して位置決めされる。また、本実施形態の１次加熱処理において、小径側熱収縮チューブ４８と大径側熱収縮チューブ５０のオーバーラップ部分６６は、相互に融合することなく独立した状態で密着している。 Next, a primary heat treatment is performed to shrink the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50 by heating. The heated small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50 are thermally shrunk to a small diameter, and approach the surface of the shaft body 12, as shown in FIG. 4B. The primary heat treatment causes the small diameter side heat shrink tube 48 to adhere closely to the small diameter portion 34 of the shaft body 12, and the large diameter side heat shrink tube 50 to adhere closely to the large diameter portion 36, so that the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50 are positioned relative to the shaft body 12. In the primary heat treatment of this embodiment, the overlapping portions 66 of the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50 are in independent adhesion without being fused to each other.
　１次加熱処理の完了後に、図４Ｂに示すように、小径側熱収縮チューブ４８と大径側熱収縮チューブ５０で覆われたシャフト本体１２に対して、成形用熱収縮チューブ５６を外挿状態で配置し、２次加熱処理を行う工程を実施する。なお、成形用熱収縮チューブ５６は、シャフト本体１２のテーパ状部分３８に外挿されていると共に、変化部３７（テーパ状部分３８）よりも先端側と基端側の両側へ突出しており、小径部分３４の基端部と大径部分３６の先端部にも外挿されている。従って、小径側熱収縮チューブ４８と大径側熱収縮チューブ５０のオーバーラップ部分６６は、成形用熱収縮チューブ５６の内周側に位置している。 After the primary heat treatment is completed, as shown in FIG. 4B, the molding heat shrink tube 56 is placed in an externally inserted state on the shaft body 12 covered with the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50, and a process of performing a secondary heat treatment is performed. The molding heat shrink tube 56 is externally inserted on the tapered portion 38 of the shaft body 12, protrudes beyond the transition portion 37 (tapered portion 38) on both the tip and base ends, and is also externally inserted on the base end of the small diameter portion 34 and the tip end of the large diameter portion 36. Therefore, the overlap portion 66 of the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50 is located on the inner periphery side of the molding heat shrink tube 56.
　小径側熱収縮チューブ４８と大径側熱収縮チューブ５０のオーバーラップ部分６６は、２次加熱処理によって、図４Ｃに示すように、シャフト本体１２のテーパ状部分３８の表面に密着すると共に、溶融して融合一体化することにより厚肉の接合部６４を形成する。これにより、シャフト本体１２の表面を被覆する樹脂チューブ６２が、一体化した小径側熱収縮チューブ４８と大径側熱収縮チューブ５０とによって構成される。 The overlapping portion 66 of the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50 adheres to the surface of the tapered portion 38 of the shaft body 12 by the secondary heat treatment as shown in FIG. 4C, and melts and fuses together to form a thick joint 64. As a result, the resin tube 62 covering the surface of the shaft body 12 is composed of the integrated small diameter side heat shrink tube 48 and large diameter side heat shrink tube 50.
　本実施形態では、小径側熱収縮チューブ４８と大径側熱収縮チューブ５０が、シャフト本体１２のテーパ状部分３８の先端部においてのみオーバーラップしていることから、樹脂チューブ６２の接合部６４がテーパ状部分３８の先端部を覆う部位にのみ形成される。 In this embodiment, the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50 overlap only at the tip of the tapered portion 38 of the shaft body 12, so the joint 64 of the resin tube 62 is formed only in the area that covers the tip of the tapered portion 38.
　本実施形態において示したように、小径側熱収縮チューブ４８と大径側熱収縮チューブ５０のオーバーラップ部分は、必ずしもシャフト本体１２のテーパ状部分３８の全体にわたって設定されている必要はなく、長さ方向で部分的に設定されていてもよい。本実施形態によれば、樹脂チューブ６２の第３部位４４における接合部６４の範囲を先端側に限定することができて、テーパ状部分３８を覆う樹脂チューブ６２の第３部位４４を、大径となる基端側において薄肉とすることができる。 As shown in this embodiment, the overlapping portion of the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50 does not necessarily have to be set over the entire tapered portion 38 of the shaft body 12, but may be set partially in the length direction. According to this embodiment, the range of the joint 64 in the third portion 44 of the resin tube 62 can be limited to the tip side, and the third portion 44 of the resin tube 62 covering the tapered portion 38 can be made thin-walled on the base end side where the diameter is large.
　なお、第３部位４４における接合部６４の長さ方向での割合は、特に限定されず、例えば、接合部６４の長さ寸法は、第３部位４４の長さ寸法の半分より大きくされていてもよいし、第３部位４４の長さ寸法の１／４より小さくされていてもよい。 The lengthwise proportion of the joint 64 in the third portion 44 is not particularly limited. For example, the length dimension of the joint 64 may be greater than half the length dimension of the third portion 44, or less than 1/4 the length dimension of the third portion 44.
　次に、図５には、本発明に係る医療用シャフトの第３実施形態として、高周波ニードル７０が示されている。本実施形態においても、高周波ニードル７０は、シャフト本体７２の外周面が樹脂チューブ７４で覆われた構造を有している。 Next, FIG. 5 shows a high-frequency needle 70 as a third embodiment of a medical shaft according to the present invention. In this embodiment, the high-frequency needle 70 also has a structure in which the outer circumferential surface of the shaft body 72 is covered with a resin tube 74.
　本実施形態のシャフト本体７２は、ステンレス鋼等の金属で形成された中空又は中実のロッド状の部材とされており、小径部分７６を構成する小径ロッド部７８と大径部分８０を構成する大径ロッド部８２とを含んで構成されている。図示は省略するが、小径ロッド部７８の先端（図５中の右端）には先端チップ２４が固定されるようになっており、シャフト本体７２（小径ロッド部７８及び大径ロッド部８２）が導電体とされて先端チップ２４（穿孔用頭部２６）に電力が供給されることにより、体組織の焼灼が可能とされている。なお、シャフト本体７２は、例えば小径ロッド部７８及び／又は大径ロッド部８２の外径寸法がある程度小さく設定されること等により、ある程度の可撓性を有していることが好ましい。また、以下の説明で示される図面では、シャフト本体７２を外形で示す。 The shaft body 72 of this embodiment is a hollow or solid rod-shaped member made of a metal such as stainless steel, and is configured to include a small diameter rod portion 78 constituting the small diameter portion 76 and a large diameter rod portion 82 constituting the large diameter portion 80. Although not shown, the tip tip 24 is fixed to the tip of the small diameter rod portion 78 (the right end in FIG. 5), and the shaft body 72 (the small diameter rod portion 78 and the large diameter rod portion 82) are made conductive, and power is supplied to the tip tip 24 (the drilling head portion 26), making it possible to cauterize body tissue. It is preferable that the shaft body 72 has a certain degree of flexibility, for example, by setting the outer diameter dimensions of the small diameter rod portion 78 and/or the large diameter rod portion 82 to be somewhat small. In addition, in the drawings shown in the following description, the shaft body 72 is shown in its external shape.
　大径ロッド部８２及び小径ロッド部７８は、それぞれ例えば円環形断面又は円形断面を有しており、略全長にわたって略一定の外径寸法を有している。大径ロッド部８２の外径寸法は、小径ロッド部７８の外径寸法よりも大きくされている。かかるシャフト本体７２は、例えば大径ロッド部８２の端部に対して小径ロッド部７８を、レーザー溶接等により固定することで形成され得る。なお、例えばシャフト本体が前記実施形態のようにルーメン（内腔）を有するパイプ状である場合、略一定の外径寸法及び内径寸法を有する金属製の素管における軸方向一方の側の部分に対して径方向でかしめ加工（縮径加工）を施すことにより、大径部分（大径パイプ）と小径部分（小径パイプ）とが相互に連結された状態で形成されるようになっていてもよい。 The large diameter rod portion 82 and the small diameter rod portion 78 each have, for example, an annular or circular cross section and have a substantially constant outer diameter dimension over the entire length. The outer diameter dimension of the large diameter rod portion 82 is larger than the outer diameter dimension of the small diameter rod portion 78. Such a shaft body 72 can be formed, for example, by fixing the small diameter rod portion 78 to the end of the large diameter rod portion 82 by laser welding or the like. Note that, for example, when the shaft body is a pipe having a lumen (inner cavity) as in the above embodiment, the large diameter portion (large diameter pipe) and the small diameter portion (small diameter pipe) may be formed in a mutually connected state by performing a crimping process (diameter reduction process) in the radial direction on one axial side of a metal raw tube having a substantially constant outer diameter dimension and inner diameter dimension.
　これら小径部分７６と大径部分８０との間には、外径寸法が変化する変化部８４が設けられている。本実施形態では、大径ロッド部８２の端面に小径ロッド部７８が直接的に接続されており、大径ロッド部８２の端面において小径ロッド部７８の周囲には軸方向に対して直交する方向に広がる環状の段差状面８６が形成されている。それ故、かかる段差状面８６を含んで、小径部分７６と大径部分８０との間において外径寸法が段差状に変化する段差状部分８８が構成されており、変化部８４が段差状部分８８を有している。 A transition portion 84 in which the outer diameter dimension changes is provided between the small diameter portion 76 and the large diameter portion 80. In this embodiment, the small diameter rod portion 78 is directly connected to the end face of the large diameter rod portion 82, and an annular stepped surface 86 that extends in a direction perpendicular to the axial direction is formed around the small diameter rod portion 78 at the end face of the large diameter rod portion 82. Therefore, including the stepped surface 86, a stepped portion 88 in which the outer diameter dimension changes in a step shape is formed between the small diameter portion 76 and the large diameter portion 80, and the transition portion 84 has the stepped portion 88.
　シャフト本体７２の外周面を覆う樹脂チューブ７４は、前記第１及び第２実施形態と同様に、小径部分７６を覆う第１部位９０と、大径部分８０を覆う第２部位９２とが、略同じ厚さとされている。また、樹脂チューブ７４は、変化部８４である段差状部分８８を覆う第３部位９４が、第１部位９０及び／又は第２部位９２に比して厚肉とされた接合部９６を有している。即ち、小径側熱収縮チューブ９８と大径側熱収縮チューブ１００との何れかよりも厚さ寸法が大きい接合部９６が、シャフト本体７２の大径部分８０の端部よりも変化部８４が位置する小径部分７６側に位置している。本実施形態では、第３部位９４（接合部９６）の厚さ寸法が互いに略同じ厚さ寸法とされた小径側熱収縮チューブ９８と大径側熱収縮チューブ１００の何れの厚さ寸法よりも大きくされていると共に、接合部９６がシャフト本体７２における小径部分７６の段差状部分８８側の端部を覆う位置に設けられている。 As in the first and second embodiments, the resin tube 74 covering the outer peripheral surface of the shaft body 72 has a first portion 90 covering the small diameter portion 76 and a second portion 92 covering the large diameter portion 80 that are approximately the same thickness. The resin tube 74 also has a joint portion 96 in which a third portion 94 covering the stepped portion 88, which is the transition portion 84, is thicker than the first portion 90 and/or the second portion 92. That is, the joint portion 96, which has a thickness dimension greater than either the small diameter side heat shrink tube 98 or the large diameter side heat shrink tube 100, is located on the small diameter portion 76 side where the transition portion 84 is located, rather than the end of the large diameter portion 80 of the shaft body 72. In this embodiment, the thickness dimension of the third portion 94 (joint 96) is greater than the thickness dimension of either the small diameter side heat shrink tube 98 or the large diameter side heat shrink tube 100, which are both approximately the same thickness dimension, and the joint 96 is located in a position that covers the end of the small diameter portion 76 on the stepped portion 88 side of the shaft body 72.
　シャフト本体７２の表面が樹脂チューブ７４によって被覆された高周波ニードル７０は、例えば、以下の工程を含む製造方法によって製造することができる。 The high-frequency needle 70, in which the surface of the shaft body 72 is covered with a resin tube 74, can be manufactured, for example, by a manufacturing method including the following steps.
　先ず、小径部分７６と大径部分８０と変化部８４（段差状部分８８）とを備えたシャフト本体７２を準備する工程を実施する。なお、シャフト本体７２の形成方法は限定されるものではない。 First, a process is carried out to prepare the shaft body 72 having a small diameter portion 76, a large diameter portion 80, and a transition portion 84 (step portion 88). Note that the method for forming the shaft body 72 is not limited.
　次に、準備したシャフト本体７２に小径側熱収縮チューブ９８と大径側熱収縮チューブ１００とを外挿する工程を実施する。即ち、小径側熱収縮チューブ９８をシャフト本体７２の小径部分７６に外挿し、且つ大径側熱収縮チューブ１００をシャフト本体７２の大径部分８０に外挿する。また、大径側熱収縮チューブ１００を、シャフト本体７２の大径部分８０から変化部８４側に延び出させて、シャフト本体７２の大径部分８０よりも変化部８４側において小径側熱収縮チューブ９８にオーバーラップさせて配置する。要するに、大径側熱収縮チューブ１００をシャフト本体７２の大径部分８０から段差状部分８８を越えて延び出させて、小径部分７６において小径側熱収縮チューブ９８にオーバーラップさせて配置する。なお、例えば小径側熱収縮チューブ９８の内径寸法は、シャフト本体７２における大径部分８０の外径寸法よりも小さくされており、小径側熱収縮チューブ９８は、端部がシャフト本体７２における段差状面８６に突き当たるようにして、小径部分７６に外挿され得る。 Next, a process is carried out in which the small diameter side heat shrink tube 98 and the large diameter side heat shrink tube 100 are fitted around the prepared shaft body 72. That is, the small diameter side heat shrink tube 98 is fitted around the small diameter portion 76 of the shaft body 72, and the large diameter side heat shrink tube 100 is fitted around the large diameter portion 80 of the shaft body 72. The large diameter side heat shrink tube 100 is extended from the large diameter portion 80 of the shaft body 72 toward the change portion 84 side, and is arranged so as to overlap the small diameter side heat shrink tube 98 on the change portion 84 side of the large diameter portion 80 of the shaft body 72. In other words, the large diameter side heat shrink tube 100 is extended from the large diameter portion 80 of the shaft body 72 beyond the stepped portion 88, and is arranged so as to overlap the small diameter side heat shrink tube 98 at the small diameter portion 76. For example, the inner diameter of the small diameter heat shrink tube 98 is smaller than the outer diameter of the large diameter portion 80 of the shaft body 72, and the small diameter heat shrink tube 98 can be inserted onto the small diameter portion 76 so that its end abuts against the stepped surface 86 of the shaft body 72.
　具体的には、図６Ａに示すように、シャフト本体７２に外挿された小径側熱収縮チューブ９８と大径側熱収縮チューブ１００は、シャフト本体７２の大径部分８０の端部よりも変化部８４が位置する小径部分７６側の外周において径方向の投影で重なり合うオーバーラップ状態とされる。即ち、小径側熱収縮チューブ９８の基端が大径側熱収縮チューブ１００の先端よりも基端側に位置しており、小径側熱収縮チューブ９８の基端部が大径側熱収縮チューブ１００の先端部の内周へ差し入れられて、オーバーラップ部分１０２が設けられている。本実施形態では、小径側熱収縮チューブ９８と大径側熱収縮チューブ１００のオーバーラップ部分１０２が、変化部８４（段差状部分８８）から先端方向に向かってある程度の軸方向寸法をもって連続的に設定されている。 Specifically, as shown in FIG. 6A, the small diameter side heat shrink tube 98 and the large diameter side heat shrink tube 100 fitted onto the shaft body 72 are overlapped in radial projection on the outer periphery of the small diameter portion 76 side where the transition portion 84 is located, rather than the end of the large diameter portion 80 of the shaft body 72. That is, the base end of the small diameter side heat shrink tube 98 is located on the base end side of the tip of the large diameter side heat shrink tube 100, and the base end of the small diameter side heat shrink tube 98 is inserted into the inner circumference of the tip of the large diameter side heat shrink tube 100 to provide an overlap portion 102. In this embodiment, the overlap portion 102 of the small diameter side heat shrink tube 98 and the large diameter side heat shrink tube 100 is set continuously with a certain axial dimension from the transition portion 84 (step portion 88) toward the tip.
　次に、小径側熱収縮チューブ９８と大径側熱収縮チューブ１００を加熱によって収縮させる１次加熱処理を行う工程を実施する。なお、これら小径側熱収縮チューブ９８及び大径側熱収縮チューブ１００は、前記第１及び第２実施形態と同様に、加熱装置５４によって加熱され得る。そして、加熱装置５４によって温められた小径側熱収縮チューブ９８と大径側熱収縮チューブ１００は、熱収縮して小径となることにより、図６Ｂに示すように、シャフト本体７２の表面にそれぞれ接近する。例えば、１次加熱処理によって、小径側熱収縮チューブ９８がシャフト本体７２の小径部分７６に密着すると共に、大径側熱収縮チューブ１００がシャフト本体７２の大径部分８０に密着して、それら小径側熱収縮チューブ９８と大径側熱収縮チューブ１００がシャフト本体７２に対して位置決めされる。小径側熱収縮チューブ９８と大径側熱収縮チューブ１００とは、オーバーラップ部分１０２において径方向で相互に離隔している。 Next, a step of performing a primary heating process is performed to shrink the small diameter side heat shrink tube 98 and the large diameter side heat shrink tube 100 by heating. The small diameter side heat shrink tube 98 and the large diameter side heat shrink tube 100 can be heated by the heating device 54, as in the first and second embodiments. The small diameter side heat shrink tube 98 and the large diameter side heat shrink tube 100 heated by the heating device 54 are thermally shrunk to a small diameter, and approach the surface of the shaft body 72, as shown in FIG. 6B. For example, the small diameter side heat shrink tube 98 is in close contact with the small diameter portion 76 of the shaft body 72 by the primary heating process, and the large diameter side heat shrink tube 100 is in close contact with the large diameter portion 80 of the shaft body 72, so that the small diameter side heat shrink tube 98 and the large diameter side heat shrink tube 100 are positioned relative to the shaft body 72. The small diameter side heat shrink tube 98 and the large diameter side heat shrink tube 100 are radially separated from each other at the overlap portion 102.
　１次加熱処理の完了後に、図６Ｂに示すように、シャフト本体７２を覆う小径側熱収縮チューブ９８と大径側熱収縮チューブ１００に対して、成形用熱収縮チューブ１０４を外挿状態で配置する工程を実施する。この成形用熱収縮チューブ１０４は、シャフト本体７２の変化部８４（段差状部分８８）に外挿されていると共に、変化部８４（段差状部分８８）よりも先端側と基端側の両側へそれぞれ延び出しており、小径部分７６の基端部と大径部分８０の先端部にも外挿されている。本実施形態では、成形用熱収縮チューブ１０４が、小径側熱収縮チューブ９８と大径側熱収縮チューブ１００とのオーバーラップ部分１０２よりも大きい軸方向寸法を有しており、オーバーラップ部分１０２の全体が、成形用熱収縮チューブ１０４によって覆われている。 After the first heat treatment is completed, as shown in FIG. 6B, a process is performed in which a molding heat shrink tube 104 is placed in an externally inserted state on the small diameter side heat shrink tube 98 and the large diameter side heat shrink tube 100 covering the shaft body 72. This molding heat shrink tube 104 is externally inserted on the transition portion 84 (step portion 88) of the shaft body 72, and extends beyond the transition portion 84 (step portion 88) to both the tip side and the base end side, and is also externally inserted on the base end of the small diameter portion 76 and the tip end of the large diameter portion 80. In this embodiment, the molding heat shrink tube 104 has an axial dimension larger than the overlap portion 102 between the small diameter side heat shrink tube 98 and the large diameter side heat shrink tube 100, and the entire overlap portion 102 is covered by the molding heat shrink tube 104.
　次に、小径側熱収縮チューブ９８及び大径側熱収縮チューブ１００と成形用熱収縮チューブ１０４を加熱装置５４によって１次加熱処理よりも更に高温まで加熱する２次加熱処理を行う工程を実施する。２次加熱処理によって、図６Ｃに示すように、小径側熱収縮チューブ９８と大径側熱収縮チューブ１００のオーバーラップ部分１０２が溶融して融合一体化することにより接合部９６が形成されると共に、接合部９６がシャフト本体７２における小径部分７６の段差状部分８８側の端部の表面を覆って密着する。これにより、シャフト本体７２の表面を被覆する樹脂チューブ７４が、一体化した小径側熱収縮チューブ９８と大径側熱収縮チューブ１００とによって構成される。 Next, a secondary heating process is carried out in which the small diameter side heat shrink tube 98, the large diameter side heat shrink tube 100, and the molding heat shrink tube 104 are heated to a temperature higher than that of the primary heating process by the heating device 54. As a result of the secondary heating process, as shown in FIG. 6C, the overlapping portion 102 of the small diameter side heat shrink tube 98 and the large diameter side heat shrink tube 100 melts and fuses together to form a joint 96, and the joint 96 covers and adheres to the surface of the end of the stepped portion 88 side of the small diameter portion 76 in the shaft main body 72. As a result, the resin tube 74 covering the surface of the shaft main body 72 is composed of the integrated small diameter side heat shrink tube 98 and large diameter side heat shrink tube 100.
　また、２次加熱処理によって熱収縮した成形用熱収縮チューブ１０４は、図６Ｃに示すように、小径側熱収縮チューブ９８と大径側熱収縮チューブ１００のオーバーラップ部分１０２に対して、外周側から押し当てられる。成形用熱収縮チューブ１０４は、変化部８４（段差状部分８８）よりも先端側及び基端側まで延び出していることから、小径部分７６の基端部及び大径部分８０の先端部まで覆うように、シャフト本体７２に密着している。本実施形態では、成形用熱収縮チューブ１０４が、オーバーラップ部分１０２の全体を覆うように設けられていることから、オーバーラップ部分１０２の全体が、成形用熱収縮チューブ１０４の当接によって形状を保持されながら融合一体化して、所定の形状に成形される。 The molding heat shrink tube 104, which has been heat shrunk by the secondary heating process, is pressed against the overlapping portion 102 of the small diameter heat shrink tube 98 and the large diameter heat shrink tube 100 from the outer periphery, as shown in FIG. 6C. The molding heat shrink tube 104 extends beyond the transition portion 84 (stepped portion 88) to the tip and base ends, and is in close contact with the shaft body 72 so as to cover the base end of the small diameter portion 76 and the tip end of the large diameter portion 80. In this embodiment, the molding heat shrink tube 104 is provided to cover the entire overlapping portion 102, so that the entire overlapping portion 102 is fused and integrated while maintaining its shape by the contact of the molding heat shrink tube 104, and is molded into a predetermined shape.
　２次加熱処理の完了後に、成形用熱収縮チューブ１０４を樹脂チューブ７４の表面から取り除く工程を実施する。これにより、シャフト本体７２の表面が樹脂チューブ７４で被覆された高周波ニードル７０を得ることができる。 After the secondary heating process is completed, a process is carried out in which the molding heat shrink tube 104 is removed from the surface of the resin tube 74. This makes it possible to obtain a high-frequency needle 70 in which the surface of the shaft body 72 is covered with the resin tube 74.
　以上の如き構造とされた本実施形態の高周波ニードル７０においても、小径側熱収縮チューブ９８と大径側熱収縮チューブ１００を重ね合わせて接合することにより形成される接合部９６が、シャフト本体７２の大径部分８０の端部よりも変化部８４が位置する小径部分７６側に設けられることから、接合部９６が形成されることによる大径化が抑制されて、前記第１及び第２実施形態と同様の効果が発揮され得る。特に、本実施形態のように、小径部分７６と大径部分８０との間に段差状の変化部８４（段差状部分８８）が設けられる場合にも、樹脂チューブ７４の外周面において小径側熱収縮チューブ９８と大径側熱収縮チューブ１００が滑らかに接続される。これにより、高周波ニードル７０がダイレータ等に挿通された場合にも、高周波ニードル７０が引っ掛かるおそれが低減され得る。 Even in the high-frequency needle 70 of this embodiment having the above structure, the joint 96 formed by overlapping and joining the small diameter side heat shrink tube 98 and the large diameter side heat shrink tube 100 is provided on the small diameter part 76 side where the change part 84 is located, rather than the end of the large diameter part 80 of the shaft body 72, so that the increase in diameter due to the formation of the joint 96 is suppressed, and the same effect as in the first and second embodiments can be achieved. In particular, even when a stepped change part 84 (stepped part 88) is provided between the small diameter part 76 and the large diameter part 80 as in this embodiment, the small diameter side heat shrink tube 98 and the large diameter side heat shrink tube 100 are smoothly connected on the outer circumferential surface of the resin tube 74. As a result, even when the high-frequency needle 70 is inserted into a dilator or the like, the risk of the high-frequency needle 70 getting caught can be reduced.
　次に、図７には、本発明に係る医療用シャフトの第４実施形態として、高周波ニードル１１０が示されている。また、図８には、本発明に係る医療用シャフトの第５実施形態として、高周波ニードル１１２が示されている。これらは何れも、第３実施形態の医療用シャフト（高周波ニードル７０）において、シャフト本体７２における大径部分８０の段差状部分８８側の端部の外周角部が面取り形状とされているものであり、図７に示される高周波ニードル１１０では外周角部がＣ面状に面取りされていると共に、図８に示される高周波ニードル１１２では外周角部がＲ面状に面取りされている。 Next, FIG. 7 shows a high-frequency needle 110 as a fourth embodiment of a medical shaft according to the present invention. Also, FIG. 8 shows a high-frequency needle 112 as a fifth embodiment of a medical shaft according to the present invention. Both of these are the third embodiment of the medical shaft (high-frequency needle 70) in which the outer circumferential corners of the end of the large diameter portion 80 of the shaft body 72 on the stepped portion 88 side are chamfered. In the high-frequency needle 110 shown in FIG. 7, the outer circumferential corners are chamfered in a C-shape, and in the high-frequency needle 112 shown in FIG. 8, the outer circumferential corners are chamfered in an R-shape.
　それ故、第４実施形態における高周波ニードル１１０では、大径部分８０の段差状部分１１３側の端部の外周端において、先端側（小径部分７６側）に向かって次第に小径となる環状のテーパ面１１４が設けられており、段差状面８６の外周端部からテーパ面１１４が基端側に連続して設けられている。この場合、段差状面８６に加えてテーパ面１１４を含んで変化部１１６（段差状部分１１３）が構成されており、テーパ面１１４の基端部（テーパ面１１４の外周端部であって、図７中の点Ｐ１）をシャフト本体７２における大径部分８０の端部と把握することができる。そして、かかる変化部１１６（テーパ面１１４及び段差状面８６）を覆うように小径側熱収縮チューブ９８と大径側熱収縮チューブ１００との何れよりも厚さ寸法が大きい接合部１１８が設けられており、当該接合部１１８が、シャフト本体７２の大径部分８０の端部（Ｐ１）よりも変化部１１６が位置する小径部分７６側に位置している。 Therefore, in the high-frequency needle 110 of the fourth embodiment, an annular tapered surface 114 that gradually becomes smaller in diameter toward the tip side (small diameter portion 76 side) is provided at the outer circumferential end of the end portion of the large diameter portion 80 on the stepped portion 113 side, and the tapered surface 114 is provided continuously from the outer circumferential end of the stepped surface 86 to the base end side. In this case, the transition portion 116 (stepped portion 113) is formed by including the tapered surface 114 in addition to the stepped surface 86, and the base end of the tapered surface 114 (the outer circumferential end of the tapered surface 114, point P1 in Figure 7) can be understood as the end portion of the large diameter portion 80 in the shaft body 72. A joint 118 having a thickness greater than both the small diameter side heat shrink tube 98 and the large diameter side heat shrink tube 100 is provided to cover the transition portion 116 (tapered surface 114 and stepped surface 86), and the joint 118 is located closer to the small diameter portion 76 where the transition portion 116 is located than the end (P1) of the large diameter portion 80 of the shaft body 72.
　同様に、第５実施形態における高周波ニードル１１２では、大径部分８０の段差状部分１１９側の端部の外周端において、先端側（小径部分７６側）に向かって次第に小径となる環状の湾曲面１２０が設けられており、段差状面８６の外周端部から湾曲面１２０が基端側に連続して設けられている。この場合、段差状面８６に加えて湾曲面１２０を含んで変化部１２２（段差状部分１１９）が構成されており、湾曲面１２０の基端部（湾曲面１２０の外周端部であって、図８中の点Ｐ２）をシャフト本体７２における大径部分８０の端部と把握することができる。そして、かかる変化部１２２（湾曲面１２０及び段差状面８６）を覆うように小径側熱収縮チューブ９８と大径側熱収縮チューブ１００との何れよりも厚さ寸法が大きい接合部１２４が設けられており、当該接合部１２４が、シャフト本体７２の大径部分８０の端部（Ｐ２）よりも変化部１２２が位置する小径部分７６側に位置している。 Similarly, in the high-frequency needle 112 of the fifth embodiment, an annular curved surface 120 that gradually becomes smaller in diameter toward the tip side (small diameter portion 76 side) is provided at the outer circumferential end of the end portion of the large diameter portion 80 on the stepped portion 119 side, and the curved surface 120 is provided continuously from the outer circumferential end of the stepped surface 86 to the base end side. In this case, the transition portion 122 (stepped portion 119) is formed by including the curved surface 120 in addition to the stepped surface 86, and the base end of the curved surface 120 (the outer circumferential end of the curved surface 120, point P2 in Figure 8) can be understood as the end portion of the large diameter portion 80 in the shaft body 72. A joint 124 having a thickness greater than both the small diameter side heat shrink tube 98 and the large diameter side heat shrink tube 100 is provided to cover the transition portion 122 (the curved surface 120 and the stepped surface 86), and the joint 124 is located closer to the small diameter portion 76 where the transition portion 122 is located than the end (P2) of the large diameter portion 80 of the shaft body 72.
　以上の如き構造とされた第４実施形態における高周波ニードル１１０及び第５実施形態における高周波ニードル１１２は、第３実施形態における高周波ニードル７０において、単に大径部分８０における段差状部分８８側の端部の外周角部を面取り形状としたものであることから、第３実施形態における高周波ニードル７０と同様の効果が発揮され得る。特に、大径部分８０における段差状部分８８側の端部の外周角部を面取り形状とすることで、当該外周角部における角張りをなくすことができると共に、接合部１１８，１２４をより肉厚とできて、例えば当該外周角部の角張りがダイレータ等に挿通された際に引っ掛かったり、高周波ニードル１１０，１１２を曲げた際に当該外周角部が樹脂チューブ７４を突き破って突出する等のおそれが低減され得る。なお、第４実施形態における高周波ニードル１１０及び第５実施形態における高周波ニードル１１２は、第３実施形態における高周波ニードル７０と同様の製造方法によって製造され得る。 The high-frequency needle 110 in the fourth embodiment and the high-frequency needle 112 in the fifth embodiment, which are constructed as described above, are simply the high-frequency needle 70 in the third embodiment, in which the outer circumferential corners of the end of the large diameter portion 80 on the stepped portion 88 side are chamfered, and therefore can exhibit the same effect as the high-frequency needle 70 in the third embodiment. In particular, by chamfering the outer circumferential corners of the end of the large diameter portion 80 on the stepped portion 88 side, the angularity of the outer circumferential corners can be eliminated, and the joints 118, 124 can be made thicker, which can reduce the risk that, for example, the angularity of the outer circumferential corners will get caught when a dilator or the like is inserted, or that the outer circumferential corners will break through the resin tube 74 and protrude when the high- frequency needles 110, 112 are bent. The high-frequency needle 110 in the fourth embodiment and the high-frequency needle 112 in the fifth embodiment can be manufactured by the same manufacturing method as the high-frequency needle 70 in the third embodiment.
　次に、図９には、本発明に係る医療用シャフトの第６実施形態として、高周波ニードル１３０が示されている。この高周波ニードル１３０には、第３実施形態の医療用シャフト（高周波ニードル７０）において、シャフト本体７２における小径部分７６の段差状部分８８側の端部に、大径部分８０よりも外径寸法の小さい中間リング１３２が外挿状態で取り付けられている。即ち、本実施形態では、小径部分７６と大径部分８０との間において外径寸法が変化する変化部１３４が、段差状面８６に加えて中間リング１３２を含んで構成されており、小径部分７６と大径部分８０との間において外径寸法が複数の段差状に変化する段差状部分１３６を有している。特に、本実施形態では、中間リング１３２の基端側端面が段差状面８６に当接しており、大径部分８０と中間リング１３２との軸方向間に隙間が設けられないようになっている。 Next, FIG. 9 shows a high-frequency needle 130 as a sixth embodiment of the medical shaft according to the present invention. In this high-frequency needle 130, an intermediate ring 132 having an outer diameter smaller than that of the large diameter portion 80 is attached in an extrapolated state to the end of the small diameter portion 76 of the shaft body 72 on the stepped portion 88 side in the medical shaft (high-frequency needle 70) of the third embodiment. That is, in this embodiment, the change portion 134 in which the outer diameter dimension changes between the small diameter portion 76 and the large diameter portion 80 is configured to include the intermediate ring 132 in addition to the stepped surface 86, and has a stepped portion 136 in which the outer diameter dimension changes in multiple steps between the small diameter portion 76 and the large diameter portion 80. In particular, in this embodiment, the base end side end face of the intermediate ring 132 abuts against the stepped surface 86, so that no gap is provided between the large diameter portion 80 and the intermediate ring 132 in the axial direction.
　そして、かかる変化部１３４（段差状部分１３６）を覆うように小径側熱収縮チューブ９８と大径側熱収縮チューブ１００との何れかよりも厚さ寸法が大きい接合部１３８が設けられており、本実施形態では、接合部１３８の厚さ寸法が、互いに略同じ厚さ寸法とされた小径側熱収縮チューブ９８と大径側熱収縮チューブ１００の何れの厚さ寸法よりも大きくされている。また、当該接合部１３８が、シャフト本体７２の大径部分８０の端部よりも変化部１３４が位置する小径部分７６側に位置している。これにより、中間リング１３２を含めてシャフト本体７２が樹脂チューブ７４により被覆されている。 A joint 138 having a thickness greater than either the small diameter side heat shrink tube 98 or the large diameter side heat shrink tube 100 is provided to cover the transition portion 134 (step portion 136). In this embodiment, the thickness of the joint 138 is greater than either the small diameter side heat shrink tube 98 or the large diameter side heat shrink tube 100, which have approximately the same thickness. The joint 138 is located closer to the small diameter portion 76, where the transition portion 134 is located, than the end of the large diameter portion 80 of the shaft body 72. As a result, the shaft body 72, including the intermediate ring 132, is covered with the resin tube 74.
　それ故、本実施形態における高周波ニードル１３０においても、前記第３実施形態に記載の高周波ニードル７０と同様の効果が発揮され得る。特に、小径部分７６の外径寸法と大径部分８０の外径寸法の差が比較的大きい場合にも、本実施形態のように小径部分７６と大径部分８０との中間の大きさの外径寸法を有する中間リング１３２を設けることで、変化部１３４として、外径寸法が複数段階で変化する段差状部分１３６を構成することができる。これにより、樹脂チューブ７４の外径寸法が、小径部分７６と大径部分８０との間で急激に変化することが回避されて、樹脂チューブ７４の外周面において小径側熱収縮チューブ９８と大径側熱収縮チューブ１００とを比較的緩やかに接続することができたり、樹脂チューブ７４の厚さ寸法が局所的に小さくなることが防止される。この結果、高周波ニードル１３０がダイレータ等に挿通された際にも、段差状部分１３６を備えることによる高周波ニードル１３０のダイレータ等への引っ掛かりが回避され得る。 Therefore, the high-frequency needle 130 in this embodiment can also achieve the same effect as the high-frequency needle 70 described in the third embodiment. In particular, even if the difference between the outer diameter dimension of the small diameter portion 76 and the outer diameter dimension of the large diameter portion 80 is relatively large, by providing an intermediate ring 132 having an outer diameter dimension intermediate between the small diameter portion 76 and the large diameter portion 80 as in this embodiment, a stepped portion 136 in which the outer diameter dimension changes in multiple steps can be formed as the changing portion 134. This prevents the outer diameter dimension of the resin tube 74 from suddenly changing between the small diameter portion 76 and the large diameter portion 80, and allows the small diameter side heat shrink tube 98 and the large diameter side heat shrink tube 100 to be connected relatively gently on the outer circumferential surface of the resin tube 74, and prevents the thickness dimension of the resin tube 74 from becoming locally small. As a result, even when the high-frequency needle 130 is inserted into a dilator or the like, the stepped portion 136 can prevent the high-frequency needle 130 from getting caught on the dilator or the like.
　なお、本実施形態の高周波ニードル１３０も基本的には、第３実施形態の高周波ニードル７０と同様の製造方法によって製造され得るが、例えば小径側熱収縮チューブ９８を小径部分７６に外挿する際に、小径側熱収縮チューブ９８は、小径部分７６に加えて中間リング１３２にも外挿されてもよい。或いは、小径側熱収縮チューブ９８は、小径部分７６における中間リング１３２よりも先端側に外挿されて、小径側熱収縮チューブ９８の基端側端面が中間リング１３２の先端側端面に当接するようになっていてもよい。何れの場合においても、大径側熱収縮チューブ１００は、大径部分８０に外挿される際に、大径部分８０から変化部１３４側に延び出させられて、大径部分８０よりも変化部１３４側において（例えば中間リング１３２の外周面や中間リング１３２よりも先端側に位置して外挿された）小径側熱収縮チューブ９８の基端側部分にオーバーラップされた状態で配置される。 The high-frequency needle 130 of this embodiment can be basically manufactured by the same manufacturing method as the high-frequency needle 70 of the third embodiment. For example, when the small-diameter heat shrink tube 98 is inserted around the small-diameter portion 76, the small-diameter heat shrink tube 98 may be inserted around the intermediate ring 132 in addition to the small-diameter portion 76. Alternatively, the small-diameter heat shrink tube 98 may be inserted around the small-diameter portion 76 on the tip side of the intermediate ring 132, so that the base end face of the small-diameter heat shrink tube 98 abuts on the tip end face of the intermediate ring 132. In either case, when the large-diameter heat shrink tube 100 is inserted around the large-diameter portion 80, it is extended from the large-diameter portion 80 to the change portion 134 side, and is arranged in an overlapping state with the base end portion of the small-diameter heat shrink tube 98 on the change portion 134 side of the large-diameter portion 80 (for example, inserted around the outer circumferential surface of the intermediate ring 132 or at the tip side of the intermediate ring 132).
　以上、本発明の実施形態について詳述してきたが、本発明はその具体的な記載によって限定されない。例えば、前記実施形態では、医療用シャフトの例として高周波ニードルを示し、通電時の絶縁被覆層として樹脂チューブを設ける態様について説明したが、樹脂チューブは、必ずしも絶縁被覆層を構成するものに限定されない。樹脂チューブは、例えば、シャフト本体の表面を保護する保護層として採用することもできる。また、医療用シャフトは、人体の施術に用いられるものに限定されず、例えば人間以外の動物の施術に用いられるものであってもよい。 Although the embodiments of the present invention have been described above in detail, the present invention is not limited to those specific descriptions. For example, in the above embodiment, a high-frequency needle is shown as an example of a medical shaft, and a resin tube is provided as an insulating coating layer when electricity is applied, but the resin tube is not necessarily limited to one that constitutes the insulating coating layer. The resin tube can also be used, for example, as a protective layer that protects the surface of the shaft body. In addition, the medical shaft is not limited to one used in treatment of the human body, and may be one used, for example, in treatment of animals other than humans.
　シャフト本体は、前記第１及び第２実施形態に示したシャフト本体１２のような小径パイプ１８と大径パイプ２０とを組み合わせた構造に限定されず、例えば全体が１つの部材で構成されていてもよい。シャフト本体は、中実ロッド状であってもよいし、材質も限定されない。シャフト本体は、先端チップ２４を備えた構造にも限定されない。 The shaft body is not limited to a structure that combines a small diameter pipe 18 and a large diameter pipe 20, such as the shaft body 12 shown in the first and second embodiments, and may be constructed as a single member, for example. The shaft body may be a solid rod, and the material is not limited. The shaft body is not limited to a structure that includes a tip 24.
　前記第１及び第２実施形態では、シャフト本体１２のテーパ状部分３８が大径パイプ２０の先端部分が小径パイプ１８にレーザー溶接される際に溶融して形成される例を示したが、シャフト本体１２のテーパ状部分３８は、例えば、小径パイプ１８と大径パイプ２０の先端側とが蝋付けによって固定される場合に、大径パイプ２０とは別の蝋材によって形成することもできる。 In the first and second embodiments, an example was shown in which the tapered portion 38 of the shaft body 12 is formed by melting when the tip portion of the large diameter pipe 20 is laser welded to the small diameter pipe 18. However, the tapered portion 38 of the shaft body 12 can also be formed from a brazing material separate from the large diameter pipe 20, for example, when the small diameter pipe 18 and the tip side of the large diameter pipe 20 are fixed by brazing.
　前記第１実施形態において、小径側熱収縮チューブ４８と大径側熱収縮チューブ５０とのオーバーラップ部分５２によって形成される樹脂チューブ１４の接合部４６は、シャフト本体１２のテーパ状部分３８における長さ方向の両端を含んで、テーパ状部分３８の全体を覆っていてもよいし、テーパ状部分３８における長さ方向の何れか一端を含んで、テーパ状部分３８を部分的に覆っていてもよい。また、かかるオーバーラップ部分５２は、テーパ状部分３８における長さ方向の両端から離れた中間部分に外挿状態で位置決めされて、テーパ状部分３８の中間部分を覆うように樹脂チューブ１４の接合部４６を設けることもできる。樹脂チューブ１４の接合部４６を、シャフト本体１２のテーパ状部分３８の大径側端部から離れて設けることで、大径部分３６の先端付近における大径化を回避できる。また、樹脂チューブ１４の接合部４６を、シャフト本体１２のテーパ状部分３８の小径側端部から離れて設けることで、小径部分３４の基端付近における大径化を回避できる。 In the first embodiment, the joint 46 of the resin tube 14 formed by the overlap portion 52 of the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50 may cover the entire tapered portion 38 including both longitudinal ends of the tapered portion 38 of the shaft body 12, or may cover only one longitudinal end of the tapered portion 38. The overlap portion 52 may be positioned in an extrapolated state in an intermediate portion away from both longitudinal ends of the tapered portion 38, and the joint 46 of the resin tube 14 may be provided to cover the intermediate portion of the tapered portion 38. By providing the joint 46 of the resin tube 14 away from the large diameter end of the tapered portion 38 of the shaft body 12, it is possible to avoid the large diameter portion 36 from becoming large near the tip. In addition, by locating the joint 46 of the resin tube 14 away from the small diameter end of the tapered portion 38 of the shaft body 12, it is possible to prevent the small diameter portion 34 from becoming large near the base end.
　前記実施形態では、１次加熱処理と２次加熱処理とによって、シャフト本体１２，７２を被覆する樹脂チューブ１４，７４が形成される製造方法について説明したが、例えば、シャフト本体１２，７２に小径側熱収縮チューブ４８，９８と大径側熱収縮チューブ５０，１００と成形用熱収縮チューブ５６，１０４とを外挿状態でそれぞれ配して、一回の加熱処理によって樹脂チューブ１４，７４を形成してもよい。また、三回以上の加熱処理によって樹脂チューブ１４，７４を形成することもできる。 In the above embodiment, a manufacturing method was described in which the resin tubes 14, 74 that cover the shaft bodies 12, 72 are formed by a primary heat treatment and a secondary heat treatment. However, for example, the small diameter side heat shrink tube 48, 98, the large diameter side heat shrink tube 50, 100, and the molding heat shrink tube 56, 104 may be placed in an externally inserted state on the shaft bodies 12, 72, respectively, and the resin tubes 14, 74 may be formed by a single heat treatment. The resin tubes 14, 74 may also be formed by three or more heat treatments.
　前記実施形態では、小径側熱収縮チューブ４８，９８と大径側熱収縮チューブ５０，１００とがシャフト本体１２，７２の外周面に対して接着又は溶着されることなく嵌合固定されている例を示したが、小径側熱収縮チューブ４８，９８と大径側熱収縮チューブ５０，１００との少なくとも一方が、シャフト本体１２，７２の外周面に対して接着又は溶着されていてもよい。例えば、第１実施形態において、シャフト本体１２の先端部分が湾曲形状とされる場合に、小径部分３４及び／又はテーパ状部分３８とその近傍において、小径側熱収縮チューブ４８と大径側熱収縮チューブ５０の少なくとも一方がシャフト本体１２に接着又は溶着される。これによれば、シャフト本体１２の先端部分を湾曲させる際に、熱収縮チューブ４８（５０）がシャフト本体１２に対してずれるのをより有利に防ぐことができる。 In the above embodiment, the small diameter side heat shrink tube 48, 98 and the large diameter side heat shrink tube 50, 100 are fitted and fixed without being bonded or welded to the outer circumferential surface of the shaft body 12, 72, but at least one of the small diameter side heat shrink tube 48, 98 and the large diameter side heat shrink tube 50, 100 may be bonded or welded to the outer circumferential surface of the shaft body 12, 72. For example, in the first embodiment, when the tip portion of the shaft body 12 is curved, at least one of the small diameter side heat shrink tube 48 and the large diameter side heat shrink tube 50 is bonded or welded to the shaft body 12 in the small diameter portion 34 and/or the tapered portion 38 and its vicinity. This makes it possible to more advantageously prevent the heat shrink tube 48 (50) from shifting relative to the shaft body 12 when the tip portion of the shaft body 12 is curved.
　また、前記第１実施形態において、成形用熱収縮チューブ５６は、テーパ状部分３８を被覆する特に熱収縮チューブ４８，５０のオーバーラップ部分５２の形状をコントロールするものであることから、シャフト本体１２の小径部分３４や大径部分３６への外挿部位では成形用熱収縮チューブ５６を充分に熱収縮させる必要はない。また、熱収縮チューブ４８，５０の材質や加熱条件、シャフト本体１２のテーパ状部分３８の傾斜角度などによっては、成形用熱収縮チューブ５６を用いることなく、接合部４６を加熱収縮成形することも可能である。或いは、接合部４６の加熱収縮成形に際して、成形用熱収縮チューブに代えて、縮径可能な絞り成形型などを用いることも可能である。これは、前記第２～第６実施形態においても同様である。 In the first embodiment, the heat shrink tube 56 for molding is used to control the shape of the overlapping portion 52 of the heat shrink tubes 48, 50 that cover the tapered portion 38, and therefore the heat shrink tube 56 for molding does not need to be sufficiently heat shrunk at the portion where it is inserted into the small diameter portion 34 or the large diameter portion 36 of the shaft body 12. Depending on the material and heating conditions of the heat shrink tubes 48, 50, and the inclination angle of the tapered portion 38 of the shaft body 12, it is also possible to heat shrink mold the joint 46 without using the heat shrink tube for molding 56. Alternatively, when heat shrink molding the joint 46, it is also possible to use a diameter-reducing drawing mold instead of the heat shrink tube for molding. This is the same in the second to sixth embodiments.
　また、シャフト本体の変化部の具体的な形状は前述の各実施形態によって限定的に解釈されるものではない。例えば、前記第４及び第５実施形態では、シャフト本体７２の段差状面８６の外周側（大径側）の凸角部が面取り形状（テーパ面１１４又は湾曲面１２０）とされていたが、それに加えて又は代えて、段差状面８６の内周側（小径側）の凹角部を面取り形状としてもよい。即ち、小径部分における基端において、基端側（段差状面８６側）になるにつれて外周側に広がるテーパ面又は湾曲面を設けることも可能である。更に、第４及び第５実施形態における面取り形状（テーパ面１１４又は湾曲面１２０）に加えて、第６実施形態の中間リング１３２を採用することも可能であり、また、複数段階で外径寸法が変化する中間リングや外径寸法がテーパ状に変化する単一又は複数の中間リングなども採用することができる。なお、前記第６実施形態において、中間リング１３２は、小径部分７６の段差状部分８８側の端部に外挿状態で取り付けられていたが、中間リングは大径部分に対して軸方向で僅かに離隔した位置に設けられてもよく、中間リングの基端側端面と段差状面とは当接していなくてもよい。 Furthermore, the specific shape of the change part of the shaft body is not limited to the above-mentioned embodiments. For example, in the fourth and fifth embodiments, the convex corner part on the outer circumferential side (large diameter side) of the stepped surface 86 of the shaft body 72 is chamfered (tapered surface 114 or curved surface 120), but in addition to or instead of that, the concave corner part on the inner circumferential side (small diameter side) of the stepped surface 86 may be chamfered. That is, at the base end of the small diameter part, it is also possible to provide a tapered surface or curved surface that widens toward the outer circumferential side as it approaches the base end side (stepped surface 86 side). Furthermore, in addition to the chamfered shape (tapered surface 114 or curved surface 120) in the fourth and fifth embodiments, it is also possible to adopt the intermediate ring 132 of the sixth embodiment, and it is also possible to adopt an intermediate ring whose outer diameter dimension changes in multiple stages or a single or multiple intermediate ring whose outer diameter dimension changes in a tapered manner. In the sixth embodiment, the intermediate ring 132 was attached in an externally inserted state to the end of the small diameter portion 76 on the stepped portion 88 side, but the intermediate ring may be provided at a position slightly spaced axially from the large diameter portion, and the base end face of the intermediate ring and the stepped surface may not be in contact.
　さらに、例えば前記第１実施形態では、１次加熱処理前において小径側熱収縮チューブ４８が小径部分３４からテーパ状部分３８にかけて外挿されて設けられると共に、大径側熱収縮チューブ５０が大径部分３６からテーパ状部分３８にかけて外挿されて設けられており、これら小径側熱収縮チューブ４８と大径側熱収縮チューブ５０がテーパ状部分３８で重ね合わされていたが、この態様に限定されるものではない。例えば１次加熱処理前において、小径側熱収縮チューブと大径側熱収縮チューブとの中間の径寸法を有する中間チューブを採用して、かかる中間チューブを含めて小径側熱収縮チューブ又は大径側熱収縮チューブを構成してもよい。かかる中間チューブは、テーパ状部分３８に配設し、軸方向一方の端部において大径側熱収縮チューブと重なり合って一体的に熱溶着されると共に、軸方向他方の端部において小径側熱収縮チューブと重なり合って一体的に熱溶着されることとなり、このような態様によれば、例えばテーパ状部分３８における径寸法変化量が大きかったり軸方向長さが長かった場合にも有利に対処することが可能になる。 Furthermore, for example, in the first embodiment, before the primary heat treatment, the small diameter side heat shrink tube 48 is fitted from the small diameter portion 34 to the tapered portion 38, and the large diameter side heat shrink tube 50 is fitted from the large diameter portion 36 to the tapered portion 38, and these small diameter side heat shrink tube 48 and large diameter side heat shrink tube 50 are overlapped at the tapered portion 38, but this is not limited to the above embodiment. For example, before the primary heat treatment, an intermediate tube having a diameter dimension intermediate between the small diameter side heat shrink tube and the large diameter side heat shrink tube may be used, and the small diameter side heat shrink tube or the large diameter side heat shrink tube may be configured including the intermediate tube. Such an intermediate tube is disposed in the tapered portion 38, overlapping and heat-welding the large-diameter heat-shrinkable tube at one axial end, and overlapping and heat-welding the small-diameter heat-shrinkable tube at the other axial end. This type of configuration makes it possible to advantageously deal with cases where the diameter change in the tapered portion 38 is large or the axial length is long.
　すなわち、本発明に係る小径側熱収縮チューブ及び／又は大径側熱収縮チューブはそれぞれ単一のチューブである必要はなく、それぞれ小径部分又は大径部分を覆うチューブと変化部を覆うチューブとの２つ或いはそれ以上の径寸法の異なるチューブを含んで構成されてもよい。 In other words, the small diameter side heat shrink tube and/or the large diameter side heat shrink tube of the present invention do not each need to be a single tube, but may each be comprised of two or more tubes with different diameter dimensions, a tube covering the small diameter portion or the large diameter portion, and a tube covering the transition portion.
　更にまた、前記実施形態では、接合部４６，６４，９６，１１８，１２４，１３８の厚さ寸法が、小径側熱収縮チューブ４８，９８及び大径側熱収縮チューブ５０，１００のそれぞれの厚さ寸法より大きくされていたが、この態様に限定されるものではない。例えば、小径側熱収縮チューブと大径側熱収縮チューブは互いに厚さ寸法が異なっていてもよい。特に、図６Ａのように変化部が段差状部分により構成された場合であって、大径側熱収縮チューブ（例えば図６Ａ中の大径側熱収縮チューブ１００）が小径側熱収縮チューブ（例えば図６Ａ中の小径側熱収縮チューブ９８）よりも厚さ寸法が大きい場合には、段差状部分の段差高さにもよるが、接合部（例えば図６Ｃ中の接合部９６）の厚さ寸法は、小径側熱収縮チューブの厚さ寸法より大きくされるが、大径側熱収縮チューブの溶け流れ等に伴って、当該大径側熱収縮チューブの厚さ寸法より小さくなることも想定される。 Furthermore, in the above embodiment, the thickness dimension of the joints 46, 64, 96, 118, 124, 138 was larger than the thickness dimension of each of the small diameter side heat shrink tube 48, 98 and the large diameter side heat shrink tube 50, 100, but this is not limited to this embodiment. For example, the small diameter side heat shrink tube and the large diameter side heat shrink tube may have different thickness dimensions. In particular, when the transition portion is configured by a stepped portion as shown in FIG. 6A, and the large diameter side heat shrink tube (e.g., the large diameter side heat shrink tube 100 in FIG. 6A) has a larger thickness dimension than the small diameter side heat shrink tube (e.g., the small diameter side heat shrink tube 98 in FIG. 6A), depending on the step height of the stepped portion, the thickness dimension of the joint (e.g., the joint 96 in FIG. 6C) is larger than the thickness dimension of the small diameter side heat shrink tube, but it is also assumed that the thickness dimension of the joint (e.g., the joint 96 in FIG. 6C) may become smaller than the thickness dimension of the large diameter side heat shrink tube due to melting and flowing of the large diameter side heat shrink tube.
１０　高周波ニードル（医療用シャフト　第１実施形態）
１２　シャフト本体
１４　樹脂チューブ
１６　ルーメン
１８　小径パイプ
２０　大径パイプ
２２　サイドホール
２４　先端チップ
２６　穿孔用頭部
２８　接続部分
３０　貫通孔
３２　先細部
３４　小径部分
３６　大径部分
３７　変化部
３８　テーパ状部分
４０　第１部位
４２　第２部位
４４　第３部位
４６　接合部
４８　小径側熱収縮チューブ
５０　大径側熱収縮チューブ
５２　オーバーラップ部分
５４　加熱装置
５６　成形用熱収縮チューブ
６０　高周波ニードル（医療用シャフト　第２実施形態）
６２　樹脂チューブ
６４　接合部
６６　オーバーラップ部分
７０　高周波ニードル（医療用シャフト　第３実施形態）
７２　シャフト本体
７４　樹脂チューブ
７６　小径部分
７８　小径ロッド部
８０　大径部分
８２　大径ロッド部
８４　変化部
８６　段差状面
８８　段差状部分
９０　第１部位
９２　第２部位
９４　第３部位
９６　接合部
９８　小径側熱収縮チューブ
１００　大径側熱収縮チューブ
１０２　オーバーラップ部分
１０４　成形用熱収縮チューブ
１１０　高周波ニードル（医療用シャフト　第４実施形態）
１１２　高周波ニードル（医療用シャフト　第５実施形態）
１１３　段差状部分
１１４　テーパ面
１１６　変化部
１１８　接合部
１１９　段差状部分
１２０　湾曲面
１２２　変化部
１２４　接合部
１３０　高周波ニードル（医療用シャフト　第６実施形態）
１３２　中間リング
１３４　変化部
１３６　段差状部分
１３８　接合部 10 High-frequency needle (medical shaft, first embodiment)
12 Shaft body 14 Resin tube 16 Lumen 18 Small diameter pipe 20 Large diameter pipe 22 Side hole 24 Distal tip 26 Drilling head 28 Connection portion 30 Through hole 32 Tapered portion 34 Small diameter portion 36 Large diameter portion 37 Transition portion 38 Tapered portion 40 First portion 42 Second portion 44 Third portion 46 Joint portion 48 Small diameter side heat shrink tube 50 Large diameter side heat shrink tube 52 Overlap portion 54 Heating device 56 Molding heat shrink tube 60 High frequency needle (medical shaft, second embodiment)
62 Resin tube 64 Joint portion 66 Overlap portion 70 High-frequency needle (medical shaft, third embodiment)
72 Shaft body 74 Resin tube 76 Small diameter portion 78 Small diameter rod portion 80 Large diameter portion 82 Large diameter rod portion 84 Transition portion 86 Step surface 88 Step portion 90 First portion 92 Second portion 94 Third portion 96 Joint portion 98 Small diameter side heat shrink tube 100 Large diameter side heat shrink tube 102 Overlap portion 104 Molding heat shrink tube 110 High frequency needle (medical shaft, fourth embodiment)
112 High frequency needle (medical shaft, fifth embodiment)
113 Stepped portion 114 Tapered surface 116 Changed portion 118 Joint portion 119 Stepped portion 120 Curved surface 122 Changed portion 124 Joint portion 130 High-frequency needle (medical shaft, sixth embodiment)
132 Intermediate ring 134 Transition portion 136 Step portion 138 Joint portion

Claims (22)

  1. 　動物への施術に際して体内に差し入れられる医療用シャフトであって、
    　シャフト本体は、長さ方向で外径寸法が異ならされて小径部分と大径部分とを有しており、該小径部分と該大径部分との間には外径寸法が変化する変化部が設けられている一方、
    　該シャフト本体は、該小径部分から該変化部を経て該大径部分に至る領域が長さ方向で連続して樹脂チューブで被覆されていると共に、
    　該樹脂チューブが、該小径部分を覆う小径側熱収縮チューブと該大径部分を覆う大径側熱収縮チューブとが接合された接合構造体とされており、
    　該小径側熱収縮チューブと該大径側熱収縮チューブとにおける厚さ寸法の小さい方の熱収縮チューブの配設領域に設けられて且つ該厚さ寸法の小さい方の熱収縮チューブよりも厚さ寸法が大きくされた接合部が、該シャフト本体の該大径部分の端部よりも該変化部が位置する該小径部分側に位置せしめられている医療用シャフト。     A medical shaft that is inserted into the body of an animal during treatment,
    The shaft body has a small diameter portion and a large diameter portion whose outer diameter dimension varies in the length direction, and a transition portion in which the outer diameter dimension varies is provided between the small diameter portion and the large diameter portion.
    The shaft body is covered in a longitudinal direction from the small diameter portion through the transition portion to the large diameter portion with a resin tube,
    the resin tube is a joint structure in which a small diameter side heat shrinkable tube covering the small diameter portion and a large diameter side heat shrinkable tube covering the large diameter portion are joined together,
    A medical shaft in which a joint is provided in an area where the smaller thickness heat shrink tube of the small diameter side heat shrink tube and the large diameter side heat shrink tube is arranged, and has a thickness dimension larger than that of the smaller thickness heat shrink tube, and is positioned on the small diameter portion side where the change portion is located, rather than the end of the large diameter portion of the shaft body.
  2. 　前記シャフト本体における前記変化部が、前記小径部分と前記大径部分との間において外径寸法が長さ方向で変化するテーパ状部分を有しており、
    　前記樹脂チューブにおける前記接合部が、該テーパ状部分を覆う部位に位置せしめられている請求項１に記載の医療用シャフト。     the transition portion of the shaft body has a tapered portion in which an outer diameter dimension changes in a longitudinal direction between the small diameter portion and the large diameter portion,
    2. The medical shaft according to claim 1, wherein the joint portion of the resin tube is positioned at a portion covering the tapered portion.
  3. 　前記シャフト本体における前記変化部が、前記小径部分と前記大径部分との間において外径寸法が段差状に変化する段差状部分を有しており、
    　前記樹脂チューブにおける前記接合部が、該シャフト本体における前記小径部分の該段差状部分側の端部を覆う部位に位置せしめられている請求項１に記載の医療用シャフト。     the transition portion of the shaft body has a step portion in which an outer diameter dimension changes stepwise between the small diameter portion and the large diameter portion,
    2. The medical shaft according to claim 1, wherein the joint portion of the resin tube is located at a portion covering the end portion of the small diameter portion of the shaft body on the stepped portion side.
  4. 　動物への施術に際して体内に差し入れられる医療用シャフトであって、
    　シャフト本体は、長さ方向で外径寸法が異ならされて小径部分と大径部分とを有しており、該小径部分と該大径部分との間には外径寸法が変化する変化部が設けられている一方、
    　該シャフト本体は、該小径部分から該変化部を経て該大径部分に至る領域が長さ方向で連続して樹脂チューブで被覆されていると共に、
    　該樹脂チューブが、該小径部分を覆う小径側熱収縮チューブと該大径部分を覆う大径側熱収縮チューブとが接合された接合構造体とされており、
    　該シャフト本体の該大径部分の端部よりも該変化部が位置する該小径部分側に位置して、該小径側熱収縮チューブと該大径側熱収縮チューブとが相互に重ね合わされて接合されている医療用シャフト。     A medical shaft that is inserted into the body of an animal during treatment,
    The shaft body has a small diameter portion and a large diameter portion whose outer diameter dimension varies in the length direction, and a transition portion in which the outer diameter dimension varies is provided between the small diameter portion and the large diameter portion.
    The shaft body is covered in a longitudinal direction from the small diameter portion through the transition portion to the large diameter portion with a resin tube,
    the resin tube is a joint structure in which a small diameter side heat shrinkable tube covering the small diameter portion and a large diameter side heat shrinkable tube covering the large diameter portion are joined together,
    A medical shaft in which the small diameter side heat shrink tube and the large diameter side heat shrink tube are overlapped and joined to each other, located on the small diameter side of the shaft body, closer to the small diameter portion where the transition portion is located, than the end of the large diameter portion.
  5. 　前記シャフト本体における前記変化部が、前記小径部分と前記大径部分との間において外径寸法が長さ方向に変化するテーパ状部分を有しており、
    　前記小径側熱収縮チューブと前記大径側熱収縮チューブとが、該シャフト本体の該テーパ状部分を覆う部位において相互に重ね合わされて接合されている請求項４に記載の医療用シャフト。     the transition portion of the shaft body has a tapered portion in which an outer diameter dimension changes in a longitudinal direction between the small diameter portion and the large diameter portion,
    5. The medical shaft according to claim 4, wherein the small diameter heat shrinkable tube and the large diameter heat shrinkable tube are overlapped and joined to each other at a portion covering the tapered portion of the shaft body.
  6. 　前記シャフト本体における前記変化部が、前記小径部分と前記大径部分との間において外径寸法が段差状に変化する段差状部分を有しており、
    　前記小径側熱収縮チューブと前記大径側熱収縮チューブとが、該シャフト本体における該小径部分の該段差状部分側の端部を覆う部位において相互に重ね合わされて接合されている請求項４に記載の医療用シャフト。     the transition portion of the shaft body has a step portion in which an outer diameter dimension changes stepwise between the small diameter portion and the large diameter portion,
    5. The medical shaft according to claim 4, wherein the small diameter side heat shrink tube and the large diameter side heat shrink tube are overlapped and joined to each other at a portion covering the end of the small diameter portion of the shaft body on the stepped portion side.
  7. 　前記シャフト本体における前記大径部分の前記段差状部分側の端部の外周角部が、面取り形状とされている請求項３又は６に記載の医療用シャフト。 The medical shaft according to claim 3 or 6, wherein the outer circumferential corner of the end of the large diameter portion of the shaft body on the stepped portion side is chamfered.
  8. 　前記シャフト本体における前記小径部分の前記段差状部分側の端部には、前記大径部分よりも外径寸法の小さい中間リングが外挿状態で取り付けられており、該中間リングを含めて該シャフト本体が前記樹脂チューブで被覆されている請求項３又は６に記載の医療用シャフト。 The medical shaft according to claim 3 or 6, in which an intermediate ring having an outer diameter smaller than that of the large diameter portion is attached in an externally inserted state to the end of the small diameter portion of the shaft body on the stepped portion side, and the shaft body including the intermediate ring is covered with the resin tube.
  9. 　前記樹脂チューブは、前記シャフト本体に対して、接着剤を用いないで重ね合わせ状態で固定されている請求項１～６の何れか１項に記載の医療用シャフト。 The medical shaft according to any one of claims 1 to 6, wherein the resin tube is fixed to the shaft body in an overlapping state without using adhesive.
  10. 　前記シャフト本体が金属製とされている請求項１～６の何れか１項に記載の医療用シャフト。 The medical shaft according to any one of claims 1 to 6, wherein the shaft body is made of metal.
  11. 　前記シャフト本体の表面に粗面化加工が施されている請求項１０に記載の医療用シャフト。 The medical shaft according to claim 10, wherein the surface of the shaft body is roughened.
  12. 　前記樹脂チューブの厚さ寸法が、前記シャフト本体における前記小径部分及び前記大径部分を覆う部位において０．０３～０．５０ｍｍの範囲内であり、且つ、前記テーパ状部分を覆う接合部における最大の厚さ寸法が１．００ｍｍ以下とされている請求項２又は５に記載の医療用シャフト。 The medical shaft according to claim 2 or 5, wherein the thickness dimension of the resin tube is within the range of 0.03 to 0.50 mm at the portion covering the small diameter portion and the large diameter portion of the shaft body, and the maximum thickness dimension at the joint covering the tapered portion is 1.00 mm or less.
  13. 　前記シャフト本体における前記小径部分と前記大径部分との半径寸法の差が０．１～０．８ｍｍの範囲内とされている請求項１～６の何れか１項に記載の医療用シャフト。 The medical shaft according to any one of claims 1 to 6, wherein the difference in radius between the small diameter portion and the large diameter portion of the shaft body is within the range of 0.1 to 0.8 mm.
  14. 　前記樹脂チューブにおいて、前記小径側熱収縮チューブと前記大径側熱収縮チューブとが互いに融合して一体化された状態で接合されている請求項１～６の何れか１項に記載の医療用シャフト。 The medical shaft according to any one of claims 1 to 6, wherein the small diameter heat shrink tube and the large diameter heat shrink tube are fused together and joined together in an integrated state in the resin tube.
  15. 　前記小径側熱収縮チューブと前記大径側熱収縮チューブとが同一の材質とされている請求項１～６の何れか１項に記載の医療用シャフト。 The medical shaft according to any one of claims 1 to 6, in which the small diameter side heat shrink tube and the large diameter side heat shrink tube are made of the same material.
  16. 　動物への施術に際して体内に差し入れられる医療用シャフトの製造方法であって、
    　長さ方向で外径寸法が異ならされて小径部分と大径部分とを有していると共に、該小径部分と該大径部分との間に外径寸法が変化する変化部を有しているシャフト本体を準備する工程と、
    　小径側熱収縮チューブを該シャフト本体の該小径部分に外挿し、且つ、大径側熱収縮チューブを該シャフト本体の該大径部分に外挿すると共に、該大径側熱収縮チューブを該シャフト本体の該大径部分から前記変化部側に延び出させて該シャフト本体の該大径部分よりも該変化部側において該小径側熱収縮チューブにオーバーラップさせて配置する工程と、
    　該シャフト本体に外挿された該小径側熱収縮チューブと該大径側熱収縮チューブとのオーバーラップ部分の外周を成形用熱収縮チューブで覆う工程と、
    　該成形用熱収縮チューブを加熱処理によって熱収縮させて該小径側熱収縮チューブと該大径側熱収縮チューブの該オーバーラップ部分の外周面に当接させることで該オーバーラップ部分の形状を保持させながら、該小径側熱収縮チューブと該大径側熱収縮チューブとを該加熱処理によって熱収縮させて該シャフト本体に密着させる工程と、
    　該加熱処理の終了後に該成形用熱収縮チューブを取り除く工程と
    を、含む医療用シャフトの製造方法。     A method for manufacturing a medical shaft to be inserted into the body of an animal during treatment, comprising the steps of:
    A step of preparing a shaft body having a small diameter portion and a large diameter portion whose outer diameter dimension varies in a length direction, and a transition portion between the small diameter portion and the large diameter portion where the outer diameter dimension varies;
    a step of fitting a small diameter side heat shrink tube onto the small diameter portion of the shaft body, fitting a large diameter side heat shrink tube onto the large diameter portion of the shaft body, and extending the large diameter side heat shrink tube from the large diameter portion of the shaft body toward the transition portion and overlapping the small diameter side heat shrink tube on the transition portion side of the large diameter portion of the shaft body;
    a step of covering an outer periphery of an overlapping portion between the small diameter side heat shrink tube and the large diameter side heat shrink tube that are fitted onto the shaft body with a molding heat shrink tube;
    a step of thermally shrinking the molding heat shrink tube by a heating process to bring the tube into contact with the outer peripheral surfaces of the overlapping portions of the small diameter side heat shrink tube and the large diameter side heat shrink tube, thereby maintaining the shape of the overlapping portions, and thermally shrinking the small diameter side heat shrink tube and the large diameter side heat shrink tube by the heating process to bring them into close contact with the shaft main body;
    and removing the heat shrinkable tube after the heat treatment is completed.
  17. 　前記シャフト本体における前記変化部が、前記小径部分と前記大径部分との間において外径寸法が長さ方向で変化するテーパ状部分を有しており、
    　前記加熱処理に際して、前記小径側熱収縮チューブと前記大径側熱収縮チューブとを該シャフト本体の該テーパ状部分で相互にオーバーラップさせて配置する請求項１６に記載の医療用シャフトの製造方法。     the transition portion of the shaft body has a tapered portion in which an outer diameter dimension changes in a longitudinal direction between the small diameter portion and the large diameter portion,
    The method for manufacturing a medical shaft according to claim 16, wherein, during the heat treatment, the small diameter side heat shrink tube and the large diameter side heat shrink tube are arranged to overlap each other at the tapered portion of the shaft body.
  18. 　前記シャフト本体における前記変化部が、前記小径部分と前記大径部分との間において外径寸法が段差状に変化する段差状部分を有しており、
    　前記加熱処理に際して、前記大径側熱収縮チューブを該シャフト本体の該大径部分から該段差状部分を越えて延び出させて該小径部分において前記小径側熱収縮チューブにオーバーラップさせて配置する請求項１６に記載の医療用シャフトの製造方法。     the transition portion of the shaft body has a step portion in which an outer diameter dimension changes stepwise between the small diameter portion and the large diameter portion,
    17. The method for manufacturing a medical shaft according to claim 16, wherein during the heat treatment, the large diameter side heat shrink tube is extended from the large diameter portion of the shaft body beyond the stepped portion and is positioned so as to overlap the small diameter side heat shrink tube in the small diameter portion.
  19. 　前記小径側熱収縮チューブと前記大径側熱収縮チューブが前記加熱処理によって相互に溶融する材質とされており、
    　前記成形用熱収縮チューブは該小径側熱収縮チューブと該大径側熱収縮チューブに対して前記加熱処理によって溶融しない材質とされている請求項１６～１８の何れか１項に記載の医療用シャフトの製造方法。     The small diameter side heat shrinkable tube and the large diameter side heat shrinkable tube are made of materials that melt with each other by the heat treatment,
    The method for manufacturing a medical shaft according to any one of claims 16 to 18, wherein the molding heat shrink tube is made of a material that does not melt against the small diameter side heat shrink tube and the large diameter side heat shrink tube by the heat treatment.
  20. 　前記シャフト本体の前記テーパ状部分の傾斜角度が３～６０度の範囲内とされている請求項１７に記載の医療用シャフトの製造方法。 The method for manufacturing a medical shaft according to claim 17, wherein the inclination angle of the tapered portion of the shaft body is within the range of 3 to 60 degrees.
  21. 　前記成形用熱収縮チューブは、前記シャフト本体の長さ方向において該シャフト本体の前記変化部から前記小径部分と前記大径部分とにそれぞれ延び出している請求項１６～１８の何れか１項に記載の医療用シャフトの製造方法。 The method for manufacturing a medical shaft according to any one of claims 16 to 18, wherein the molding heat shrink tube extends from the transition portion of the shaft body to the small diameter portion and the large diameter portion in the longitudinal direction of the shaft body.
  22. 　前記小径側熱収縮チューブと該大径側熱収縮チューブは、前記シャフト本体の外周面に対して全長にわたって接着又は溶着されることなく重ね合わせ状態で固定されている請求項１６～１８の何れか１項に記載の医療用シャフトの製造方法。 The method for manufacturing a medical shaft according to any one of claims 16 to 18, wherein the small diameter heat shrink tube and the large diameter heat shrink tube are fixed in an overlapping state to the outer circumferential surface of the shaft body without being glued or welded over the entire length.
PCT/JP2023/038138 2022-10-24 2023-10-23 Medical shaft and method for producing medical shaft WO2024090368A1 (en)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4636272A (en) * 1985-02-19 1987-01-13 Cordis Corporation Process for thermally bonding plastic tubes
JP2004041254A (en) * 2002-07-08 2004-02-12 Terumo Corp Guide wire
JP2017184791A (en) * 2016-03-31 2017-10-12 オリンパス株式会社 Tube fusing method and tube fusing apparatus
JP2019069186A (en) * 2014-03-24 2019-05-09 ベイリス メディカル カンパニー インコーポレイテッドＢａｙｌｉｓ Ｍｅｄｉｃａｌ Ｃｏｍｐａｎｙ Ｉｎｃ． Medical device for fluid communication

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4636272A (en) * 1985-02-19 1987-01-13 Cordis Corporation Process for thermally bonding plastic tubes
JP2004041254A (en) * 2002-07-08 2004-02-12 Terumo Corp Guide wire
JP2019069186A (en) * 2014-03-24 2019-05-09 ベイリス メディカル カンパニー インコーポレイテッドＢａｙｌｉｓ Ｍｅｄｉｃａｌ Ｃｏｍｐａｎｙ Ｉｎｃ． Medical device for fluid communication
JP2017184791A (en) * 2016-03-31 2017-10-12 オリンパス株式会社 Tube fusing method and tube fusing apparatus

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