WO2017126247A1 - Excavation tool and excavation method - Google Patents

Excavation tool and excavation method Download PDF

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Publication number
WO2017126247A1
WO2017126247A1 PCT/JP2016/086558 JP2016086558W WO2017126247A1 WO 2017126247 A1 WO2017126247 A1 WO 2017126247A1 JP 2016086558 W JP2016086558 W JP 2016086558W WO 2017126247 A1 WO2017126247 A1 WO 2017126247A1
Authority
WO
WIPO (PCT)
Prior art keywords
excavation
tip
pipe
tool
groove
Prior art date
Application number
PCT/JP2016/086558
Other languages
French (fr)
Japanese (ja)
Inventor
田中　邦彦
中村　和由
泰隆 富田
Original Assignee
三菱マテリアル株式会社
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
Application filed by 三菱マテリアル株式会社 filed Critical 三菱マテリアル株式会社
Priority to US16/065,448 priority Critical patent/US20190003261A1/en
Priority to EP16886486.6A priority patent/EP3406841A4/en
Priority to CN201680071232.3A priority patent/CN108291429A/en
Publication of WO2017126247A1 publication Critical patent/WO2017126247A1/en

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Classifications

    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B10/00—Drill bits
    • E21B10/60—Drill bits characterised by conduits or nozzles for drilling fluids
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D5/00—Bulkheads, piles, or other structural elements specially adapted to foundation engineering
    • E02D5/22—Piles
    • E02D5/34—Concrete or concrete-like piles cast in position ; Apparatus for making same
    • E02D5/36—Concrete or concrete-like piles cast in position ; Apparatus for making same making without use of mouldpipes or other moulds
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B10/00—Drill bits
    • E21B10/36—Percussion drill bits
    • E21B10/38—Percussion drill bits characterised by conduits or nozzles for drilling fluids
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B21/00—Methods or apparatus for flushing boreholes, e.g. by use of exhaust air from motor
    • E21B21/14—Methods or apparatus for flushing boreholes, e.g. by use of exhaust air from motor using liquids and gases, e.g. foams
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B7/00—Special methods or apparatus for drilling
    • E21B7/20—Driving or forcing casings or pipes into boreholes, e.g. sinking; Simultaneously drilling and casing boreholes

Definitions

  • the present invention relates to an excavation tool used in a reverse circulation method for taking in dusts generated during excavation into a tool body and discharging it through an excavation pipe, and an excavation method using the excavation tool.
  • the compressed air used to strike the drill bit is generally ejected from the tip of the drill bit, and the bedrock is crushed during the excavation.
  • a certain flour is discharged to the rear end side by the compressed air through the space between the casing pipe and the excavating rod.
  • the compressed air ejected from the tip of the excavation bit leaks into the rock surrounding the excavation hole, reducing the strength of the surrounding rock, and in some cases, the surrounding rock collapses. May be incurred.
  • Patent Document 1 supplies fresh water as carrier water through the casing pipe, and sucks and discharges the flour that is mixed with the carrier water by a vacuum pump. Drilling tools have been proposed.
  • the present invention has been made under such a background.
  • An excavation tool capable of efficiently discharging water mixed with flour without using a vacuum pump, and excavation using the excavation tool.
  • the purpose is to provide construction methods.
  • the excavation tool of the present invention has an air supply pipe for supplying compressed air to the inner periphery of the excavation pipe in which the tool body is disposed at the tip.
  • the outer periphery of the excavation pipe is provided with a water supply channel for supplying excavation water to the tip of the tool body, and the tip of the tool body is fed with the flour generated during excavation.
  • a discharge passage is formed in the space between the drilling pipe and the air supply pipe together with the drilling water supplied from the water supply passage, and an exhaust hole opening in the space is formed at the tip of the air supply pipe. It is formed.
  • the excavation method of the present invention uses such an excavation tool to supply excavation water to the tip of the tool main body through the water supply channel while forming a excavation hole by the tool main body.
  • the generated dust is discharged together with the drilling water through the discharge passage to a space between the drilling pipe and the air supply pipe, and the dust and drilling water discharged to the space are discharged from the exhaust hole. It is characterized in that it is discharged to the rear end side by compressed air that is exhausted.
  • an exhaust hole opening in a space between the excavation pipe is formed at the tip of the air supply pipe.
  • the compressed air used to strike the tool body is supplied to the air supply pipe, exhausted from the exhaust hole, and the dust and drilling water discharged into the space between the drilling pipe and the air supply pipe are discharged into the exhaust pipe.
  • the compressed air exhausted from the hole is pushed out to the rear end side and discharged.
  • the compressed air thus supplied to give a striking force to the tool body can be used for the dusting and the discharge of the excavation water.
  • the tip of the tool main body it is possible to prevent the compressed air from leaking into the rock around the excavation hole and reducing the strength, thereby causing collapse.
  • drilling water is supplied to the front-end
  • the vacuum pump is not required. There is no damage caused by passing the flour inside. Also, when compressed air is exhausted and dusting and drilling water are pushed out to the rear end side, the space on the tip side from the exhaust hole becomes negative pressure. And the drilling water can be sucked and discharged continuously.
  • the exhaust hole may be formed so as to incline toward the rear end side toward the outer peripheral side of the tool body and open into the space.
  • emitted in this space can be extruded to a rear end side, and can be discharged
  • the casing pipe is used as a water supply pipe, and the excavation pipe is inserted into the inner periphery of the water supply pipe, thereby A water supply channel may be formed between the water supply pipe and the excavation pipe. Thereby, it becomes possible to supply drilling water to the front-end
  • a plurality of groove portions extending from the front end of the tool body to the rear end side are formed on the outer periphery of the front end of the tool body.
  • some of the groove portions are communicated with the water supply channel, and the remaining groove portions are communicated with the discharge channel, and the tip portions of the some groove portions and the tip portions of the remaining groove portions are You may communicate through the communicating groove formed in the front end surface of a tool main body.
  • the dust is efficiently recovered while the drilling water supplied from some of the grooves flows into the tip of the remaining grooves via the communication grooves, and the drilling pipe and the air supply pipe are It can be discharged into the space between.
  • a groove extending from the tip of the tool body to the rear end side and communicating with the water supply channel is formed, and in the tool body on the inner peripheral side of the groove, A hole extending from the front end of the tool body toward the rear end is formed as the discharge path, and the front end of the groove and the front end of the hole are connected via a communication groove formed on the front end surface of the tool body. May be communicated. Even with such a configuration, the dusting can be efficiently recovered while the drilling water supplied from the groove similarly flows into the tip of the hole through the communication groove.
  • the excavation tool provided with the above structure can be used for the excavation method of the present invention.
  • the strength of the rock mass around the excavation hole is not lowered and collapse is not caused, and the pressure of the compressed air is not required to be increased more than necessary, and the vacuum pump is provided. Since it is not necessary, stable excavation can be performed efficiently at low cost.
  • FIG. 1st Embodiment of the excavation tool of this invention It is a front view of the tool main body of embodiment shown in FIG. It is a rear view of the shank part in the tool main body of embodiment shown in FIG. It is ZZ sectional drawing in FIG. It is a sectional side view which shows 2nd Embodiment of the excavation tool of this invention. It is a front view of the tool main body of embodiment shown in FIG. It is a rear view of the shank part in the tool main body of embodiment shown in FIG. It is ZZ sectional drawing in FIG.
  • the tool body 1 is formed of a metal material such as a steel material, and has a substantially multi-stage cylindrical shape with a bottom centered on an axis O whose front end side in the axis O direction (left side in FIG. 1) has a one-step large diameter.
  • a metal material such as steel that is detachably attached to the outer periphery of the tip end portion of the pilot bit 2. .
  • the rear end portion of the pilot bit 2 having a small diameter is a shank portion 2A having a male screw portion formed on the outer periphery, and a cylindrical excavation pipe P1 is screwed into the shank portion 2A with the male screw portion of the shank portion 2A. It is attached.
  • the pilot bit 2 is given a rotational force around the axis O, and a thrust and striking force toward the tip side in the direction of the axis O.
  • the direction in which the axis O extends is referred to as the axis O direction
  • the direction from the excavation pipe P1 to the pilot bit 2 in the axis O direction is referred to as the tip side (left side in FIG. 1).
  • a direction from 2 to the excavation pipe P1 is referred to as a rear end side (right side in FIG. 1).
  • a direction passing through the axis O and orthogonal to the axis O is referred to as a radial direction or a radial direction.
  • the direction approaching the axis O is referred to as the inner peripheral side
  • the direction away from the axis O is referred to as the outer peripheral side.
  • a direction that circulates around the axis O is referred to as a circumferential direction.
  • the tip portion of the pilot bit 2 on the tip side of the shank portion 2A is formed so as to be reduced in diameter to approximately three steps toward the tip side. That is, the front end portion of the pilot bit 2 has, in order from the rear end side, a large diameter portion 2B having the largest outer diameter, a medium diameter portion 2C having an outer diameter smaller than that of the large diameter portion 2B, and an outer diameter smaller than that of the medium diameter portion 2C. A small small-diameter portion 2D. Among these, between the outer peripheral surface of the large-diameter portion 2B located on the most rear end side and the outer peripheral surface of the next medium-diameter portion 2C, the axis O gradually decreases toward the front end side in the axis O direction.
  • the pilot bit side contact surface 4 having a conical surface is formed.
  • the pilot bit side contact surface 5 is closer to the axis O than the inclination angle ⁇ formed by the pilot bit side contact surface 4 with respect to the axis O.
  • the inclination angle ⁇ is set small.
  • the length A in the direction parallel to the axis O on the pilot bit side contact surface 4 is reduced when the length A is directed toward the tip side in the axis O direction. It is formed so as to be equal to or less than the radius (the amount of decrease in radius) B, that is, the inclination angle ⁇ formed with respect to the axis O is 45 ° or more.
  • the pilot bit side contact surface 5 has a radius (a decrease in radius) that reduces the length C in the direction parallel to the axis O toward the tip side in the direction of the axis O by the length C.
  • the angle ⁇ formed with respect to the axis O is less than 45 °.
  • the length C of the pilot bit side contact surface 5 is sufficiently longer than the length B of the pilot bit side contact surface 4, and the radius D of the pilot bit side contact surface 5 is equal to the pilot bit side contact surface 5. It is set to be slightly larger than the radius B of the surface 4.
  • the outer peripheral surfaces of the large-diameter portion 2B, the medium-diameter portion 2C, and the small-diameter portion 2D are cylindrical surfaces having a constant outer diameter centered on the axis O, and of these, the axis O of the medium-diameter portion 2C. The length in the direction is set slightly longer than the large diameter portion 2B and the small diameter portion 2D.
  • a plurality of grooves 6 are formed at substantially equal intervals in the circumferential direction extending from the front end surface of the pilot bit 2 to the rear end.
  • a part of the groove portions one groove portion on the upper side in FIG. 1 and one groove on the left side in FIG. 2 6 ⁇ / b> A penetrates from the front end surface of the pilot bit 2 to the rear end surface of the large diameter portion 2 ⁇ / b> B. Yes.
  • the remaining groove portions the two groove portions on the lower side in FIG. 1 and the right side in FIG.
  • 6B extend from the front end surface of the pilot bit 2 to the front of the large-diameter portion 2B and cut off to the outer peripheral side. ing.
  • the remaining groove 6B extends from the front end surface of the pilot bit 2 to the vicinity of the rear end of the medium diameter part 2C in the medium diameter part 2C.
  • a hole having a circular cross-section toward the rear end side is formed as the discharge path 7 in the present embodiment toward the inner peripheral side.
  • One end of this hole portion opens to the inner peripheral portion (inner peripheral surface) of the bottomed cylindrical pilot bit 2, and the other end opens to the rear end portion of the remaining groove portion 6B.
  • a communication groove 8 is formed on the front end surface of the pilot bit 2 to connect the front end of the partial groove 6A and the front end of the remaining groove 6B.
  • the communication groove 8 extends from the front end of a part of the groove 6A in the radial direction with respect to the axis O to the front of the axis O as shown in FIG. It is formed in a Y-shape that reaches the leading ends of the two remaining grooves 6B while branching and curving in two without reaching.
  • the groove portion 6 has a substantially square or substantially U-shaped cross section, and the bottom surface facing the outer peripheral side is slightly with respect to the axis O so as to go to the outer peripheral side toward the rear end side as shown in FIG. It is inclined.
  • the communication groove 8 has a U-shaped cross section and extends on a plane perpendicular to the axis O.
  • a central face surface that is perpendicular to the axis O and toward the outer peripheral side toward the rear end side.
  • a conical surface-shaped outer peripheral gauge surface is formed on these face surface and gauge surface.
  • an excavation tip 9 made of cemented carbide harder than the pilot bit 2 is implanted perpendicularly to the face surface and gauge surface so as to avoid the opening of the groove portion 6 and the communication groove 8. It is installed.
  • the outer peripheral surface of the small-diameter portion 2D of the pilot bit 2 has an arc plate-shaped protrusion (having an outer peripheral surface that is an arc surface centered on the axis O) centered on the axis O protruding outward.
  • the section 2E is formed with a plurality of strips (three strips in the present embodiment) at equal intervals in the circumferential direction at positions spaced apart from the pilot bit side contact surface 5 by a slight distance.
  • these protrusions 2E extend from one end in the circumferential direction of the groove 6 (the end in the counterclockwise direction when viewed from the front as shown in FIG. 2). It is planted over the ridge 2E.
  • the axial line O is gradually reduced in diameter toward the front end side in the axis O direction on the inner peripheral surface of the rear end portion.
  • a conical ring-shaped ring bit side contact surface 10 is formed.
  • the ring bit side contact surface 10 has an inclination angle ⁇ equal to the pilot bit side contact surface 5 with respect to the axis O in a cross section along the axis O.
  • the ring bit side contact surface 10 has a radius that decreases when the length C in the direction parallel to the axis O is the same as the pilot bit side contact surface 5 toward the tip side in the axis O direction by this length C. It is formed so as to be longer than D, and is formed at an inclination angle ⁇ of less than 45 ° with respect to the axis O. 1, the ring bit side contact surface 10 is brought into close contact with the pilot bit side contact surface 5 as shown in FIG. 1, and the pilot bit side contact surface 5 extends from the front end surface of the pilot bit 2 in the axis O direction. Installed over the rear edge.
  • the length of the ring bit 3 in the axis O direction is substantially the same as the length in the axis O direction from the front end surface of the pilot bit 2 to the rear end of the pilot bit side contact surface 5.
  • the ring bit 3 is attached to the outer periphery of the pilot bit 2 so that the position of the tip surface of the ring bit 3 is substantially the same as the tip surface of the pilot bit 2 in the direction of the axis O.
  • the inner peripheral surface of the tip portion of the ring bit 3 has an inner diameter slightly larger than the small diameter portion 2D of the pilot bit 2.
  • On the inner peripheral surface of the tip there are concave grooves 3A that are slightly wider in the circumferential direction than the ridges 2E of the pilot bit 2.
  • the same number as the ridges 2E at equal intervals in the circumferential direction and ring in the direction of the axis O It is formed so as to penetrate from the tip surface of the bit 3 toward the ring bit side contact surface 10.
  • the depth in the radial direction of the groove 3A is set so that the inner diameter of the groove 3A is slightly larger than the outer diameter of the protrusion 2E.
  • the protrusion 2E is accommodated in the concave groove 3A, the ring bit 3 is inserted from the tip side of the tip of the pilot bit 2, and the pilot bit 2 is rotated to one end side in the circumferential direction (counterclockwise direction in FIG. 2).
  • the protruding portion 2E is engaged with the engaging portion 3B. Therefore, the position of the groove portion 6 of the pilot bit 2 coincides with the concave groove portion 3A of the ring bit 3 in the circumferential direction in a state where the protruding portion 2E is fitted to the engaging portion 3B.
  • the circumferential width of the engaging portion 3B is such that the position of the groove portion 6 of the pilot bit 2 overlaps with the concave groove portion 3A of the ring bit 3 in the circumferential direction in a state where the protruding portion 2E is fitted to the engaging portion 3B. Is set as follows. In the present embodiment, the circumferential width of the engaging portion 3B is set to be approximately the same as the circumferential width of the protrusion 2E.
  • the front end surface of the ring bit 3 also includes an inner peripheral face surface perpendicular to the axis O, and an outer peripheral gauge surface that inclines toward the outer peripheral side toward the rear end side.
  • a drilling tip 9 made of a cemented carbide harder than the ring bit 3 is implanted perpendicularly to the face surface and gauge surface.
  • a plurality of concave grooves 3C are formed at equal intervals in the circumferential direction between the excavation tips 9 planted on the gauge surface on the outer peripheral surface of the tip portion of the ring bit 3.
  • the outer peripheral surface of the ring bit 3 has a rectangular shape with a cross section along the axis O extending in the axis O direction at a position spaced from the gauge surface and the rear end surface of the front end surface in the axis O direction.
  • a ring bit side locking groove 11 opened to the outer peripheral side is formed over the entire periphery.
  • the outer peripheral portion of the ring bit 3 on the rear end side of the ring bit side locking groove 11 is an annular ring bit side locking portion 12 that protrudes toward the outer peripheral side with respect to the ring bit side locking groove 11. ing.
  • the outer diameter of the ring bit side locking portion 12 is smaller than the tip of the ring bit 3, and the length in the direction of the axis O is set shorter than the ring bit side locking groove 11. Note that the outer peripheral portion of the rear end of the ring bit side locking portion 12 is chamfered.
  • a cylindrical casing pipe 13 centering on the axis O is disposed as the water supply pipe P2 in the present embodiment on the outer periphery of the pilot bit 2 to which the ring bit 3 is attached as described above. Yes.
  • a water supply path F is formed between the outer periphery of the excavation pipe P1 and the casing pipe 13 (water supply pipe P2).
  • the casing pipe 13 is obtained by integrating a cylindrical casing top 13B, which is also centered on the axis O, with a tip end portion of a cylindrical pipe body 13A centering on the axis O by welding or the like.
  • the pipe body 13A has an inner diameter larger than the outer diameter of the large-diameter portion 2B of the pilot bit 2, and a plurality of pipe bodies 13A are welded or the like to the rear end side of the pipe body 13A according to the depth of the drilling hole. It will be added sequentially.
  • the casing top 13B is formed so that the outer diameter of the rear end portion thereof is one step smaller than that of the tip end portion, and the tip end portion of the most advanced pipe body 13A is fitted and joined to the step portion.
  • the outer diameter of the rear end portion of the casing top 13B is substantially the same as the inner diameter of the front end portion of the pipe body 13A, and the rear end portion of the casing top 13B is fitted and joined to the pipe body 13A.
  • the inner diameter of the rear end portion of the casing top 13B is set to be slightly smaller than the outer diameter of the large diameter portion 2B of the pilot bit 2 and slightly larger than the outer diameter of the medium diameter portion 2C.
  • a casing pipe that can be brought into contact with the pilot bit side contact surface 4 formed on the rear end side of the pilot bit side contact surface 5 of the pilot bit 2 on the inner peripheral portion of the rear end surface of the casing top 13B.
  • a side contact surface 14 is formed.
  • the casing pipe side contact surface 14 is also formed in a conical surface shape with the axis O gradually decreasing in diameter toward the tip end side in the axis O direction.
  • the inclination angle ⁇ formed with respect to the axis O is equal to the inclination angle ⁇ of the pilot bit side contact surface 4, and the pilot bit side contact surface 5 and the ring bit side The angle is larger than the inclination angle ⁇ formed by the contact surface 10.
  • the inclination angle ⁇ is set to 45 ° or more.
  • the outer diameter of the tip of the casing top 13B is set equal to the outer diameter of the pipe body 13A, and is set smaller than the outer diameter of the tip that is the maximum outer diameter of the ring bit 3.
  • a casing pipe-side locking groove 15 that opens inward on the inner peripheral side of the casing top 13 ⁇ / b> B in a rectangular shape with a cross section along the axis O extending in the direction of the axis O in order toward the tip.
  • a casing pipe side latching portion 16 that protrudes inward from the casing pipe side latching groove 15 is formed over the entire circumference.
  • the casing pipe side locking groove 15 and the casing pipe side locking portion 16 are set to have the same length in the axis O direction as the ring bit side locking groove 11 and the ring bit side locking portion 12, respectively.
  • the inner diameter of the casing pipe side locking groove 15 is set to be slightly larger than the outer diameter of the ring bit side locking portion 12.
  • the inner diameter of the casing pipe side locking portion 16 is set to be slightly larger than the outer diameter of the ring bit side locking groove 11 and smaller than the outer diameter of the ring bit side locking portion 12, Has been chamfered.
  • the ring bit 3 is rotated around the axis O. It is attached to the casing top 13B in a state that it is freely rotatable and is also locked to the front end side and the rear end side in the axis O direction within a range in which the ring bit side locking groove 11 and the casing pipe side locking groove 15 are formed.
  • the chamfered portions of the rear end outer peripheral portion of the ring bit side locking portion 12 and the front end inner peripheral portion of the casing pipe side locking portion 16 are mutually connected.
  • the rear end portion of the ring bit 3 is elastically reduced in diameter by pressing at least one of the casing top 13B and the ring bit 3 in the direction of the axis O toward the other.
  • the tip end portion of the casing top 13B is elastically expanded so that the casing pipe side locking portion 16 is in the ring bit side locking groove 11 and the ring bit side locking portion 12 is in the casing pipe side locking groove 15. What is necessary is just to accommodate so that it may each fit.
  • the pilot bit 2 attached to the front end of the excavation pipe P1 is inserted into the casing pipe 13 from the rear end side, and As described above, the protrusion 2E is accommodated in the concave groove 3A, and then the pilot bit 2 is rotated to one end side in the circumferential direction, so that the protrusion 2E is fitted and engaged with the engaging portion 3B.
  • the excavation pipe P1 is also added and connected sequentially according to the depth of the excavation hole, and the excavation pipe P1 at the end is connected to the excavator.
  • the pilot bit 2 thus inserted into the casing pipe 13 is positioned when the pilot bit side contact surface 4 contacts the casing pipe side contact surface 14 of the casing top 13B.
  • the tip portions of the pilot bit 2 and the ring bit 3 are brought into contact with the bedrock and the like, and the rotational force around the axis O and the tip side in the axis O direction from the excavator to the pilot bit 2 via the excavation pipe P1.
  • the ring bit 3 is pressed against the rear end side by resistance from the rock or the like, and the ring bit side contact surface 10 comes into close contact with the pilot bit side contact surface 5.
  • the ring bit 3 may be pressed to the rear end side before excavation so that the ring bit side contact surface 10 is in close contact with the pilot bit side contact surface 5.
  • the ring bit side latching portion 12 and the casing pipe side latching portion 16 are configured such that the pilot bit side contact surface 4 contacts the casing pipe side contact surface 14 and the ring bit side contact surface 10 functions as the pilot.
  • the casing pipe side locking groove 15 and the ring bit side locking groove 11 are arranged at positions spaced from both ends in the axis O direction. It is formed to be.
  • the air supply pipe P3 is inserted from the rear end side into the inner periphery of the cylindrical excavation pipe P1, and the tip of the air supply pipe P3 is inserted into the inner periphery of the pilot bit 2 in the tool body 1. Yes. Further, an exhaust plug 17 is attached to the tip of the air supply pipe P3, and the exhaust plug 17 is accommodated in the inner peripheral portion of the pilot bit 2.
  • the air supply pipe P3 is formed in a cylindrical shape centering on an axis O having an outer diameter smaller than the inner diameter of the excavation pipe P1, and a space having an annular cross section is formed between the air supply pipe P3 and the excavation pipe P1. E is formed. Compressed air used to drive the air hammer when applying a striking force to the pilot bit 2 as described above is supplied to the inner peripheral portion of the air supply pipe P3, for example.
  • the exhaust plug 17 is formed in a bottomed multistage cylindrical shape.
  • the exhaust plug 17 includes a front end portion having a large outer diameter, a rear end portion having a small outer diameter, and an intermediate portion having an outer diameter smaller than the front end portion and larger than the rear end portion. It has a cylindrical surface shape with a substantially constant outer diameter.
  • a male screw portion that is screwed into the inner periphery of the tip end portion of the air supply pipe P3 is formed on the outer periphery of the small diameter.
  • the large-diameter tip has an outer diameter that can be fitted into the inner periphery of the pilot bit 2 with a slight gap.
  • the rear end surface of the front end portion is formed in a conical surface shape toward the rear end side toward the inner peripheral side. That is, the rear end surface of the front end portion connecting the outer peripheral surface of the front end portion and the outer peripheral surface of the intermediate portion is formed in a conical shape.
  • the inclination angle of the rear end face of the front end portion with respect to the axis O is set to be equal to the inclination angle of the pilot bit 2 toward the rear end side with respect to the axis O of the discharge passage 7 as it goes toward the inner peripheral side.
  • Such an exhaust plug 17 is attached to the front end portion of the air supply pipe P3 and inserted into the inner peripheral portion of the pilot bit 2, and as shown in FIG.
  • the inner peripheral part of the bottomed cylindrical exhaust plug 17 communicates with the inner peripheral part of the cylindrical air supply pipe P3.
  • a plurality (three) of exhaust holes 17A opening into the space E are equally spaced in the circumferential direction in the present embodiment. Is formed. That is, one end of the exhaust hole 17A opens to the inner periphery of the exhaust plug 17, and the other end opens to a connection position between the rear end surface of the front end portion of the exhaust plug 17 and the outer peripheral surface of the intermediate portion.
  • the exhaust hole 17 ⁇ / b> A of the present embodiment is inclined so as to go to the rear end side as going to the outer peripheral side of the tool body 1.
  • An exhaust hole 17B having a smaller diameter than the exhaust hole 17A is also formed from the inner peripheral portion of the exhaust plug 17 to the distal end surface of the exhaust plug 17 perpendicular to the axis O. That is, one end of the exhaust hole 17 ⁇ / b> B opens to the inner periphery of the exhaust plug 17, and the other end opens to the distal end surface of the exhaust plug 17. Further, the exhaust hole 17B is inclined so as to go to the tip side as it goes to the outer peripheral side of the tool body 1.
  • the exhaust hole 17 ⁇ / b> B has a function of discharging residual earth and sand from the inner periphery of the pilot bit 2.
  • the striking force and thrust to the front end side in the direction of the axis O given to the pilot bit 2 from the excavator through the excavation pipe P1 are as follows. It is transmitted from the bit side contact surface 4 to the casing pipe 13 via the casing pipe side contact surface 14 of the casing top 13B, and from the pilot bit side contact surface 5 to the ring bit 3 via the ring bit side contact surface 10. Communicated. As a result, the excavation hole is formed by the excavation tip 9 planted on the front end surfaces of the pilot bit 2 and the ring bit 3, and the casing pipe 13 is inserted into the excavation hole. The rotational force about the axis O applied to the pilot bit 2 is also transmitted from the pilot bit side contact surface 5 to the ring bit 3 via the ring bit side contact surface 10.
  • excavation water is supplied from the rear end side to the water supply path F between the excavation pipe P1 and the casing pipe 13 which is the water supply pipe P2.
  • the drilling water in this embodiment is fresh water such as tap water.
  • the drilling water supplied in this way flows into the bottom portion of the drilling hole from the partial groove portion 6A of the pilot bit 2 opened at the tip of the water supply channel F and fills the bottom portion.
  • the pilot bit 2 flows through the communication groove 8 and reaches the remaining groove portion 6B while winding the dust as the pilot bit 2 rotates, and further passes through the discharge path 7 communicating with the remaining groove portion 6B. It flows into the space E on the rear end side from the rear end surface of the front end portion of the exhaust plug 17 in the periphery, and is filled from the exhaust hole 17A to the rear end side.
  • the drilling water mixed with the dust filled up to the rear end side of the exhaust hole 17A in this way passes through the inner peripheral portion of the exhaust plug 17 and the exhaust air is supplied to the compressed air supplied into the air supply pipe P3. As it ejects from 17A, it is sent to the rear end side and discharged. Further, since the tip of the space E from which the drilling water has been discharged becomes negative pressure, the drilling water remaining in the discharge path 7 from the remaining groove 6B is sucked together with the flour by the tip of the space E. In this way, the drilling water and the flour are continuously discharged by the ejection of compressed air from the exhaust hole 17A.
  • the compressed air for applying the striking force to the pilot bit 2 and the ring bit 3 of the tool body 1 as described above without requiring a vacuum pump or the like. It is possible to discharge drilling water mixed with flour.
  • the excavated water to be discharged passes through the space E between the excavated pipe P1 and the air supply pipe P3. Therefore, even if dusting is mixed, the discharge is not hindered. For this reason, it is possible to achieve stable and efficient low-cost excavation and dust discharge over a long period of time.
  • the compressed air for giving a striking force is used for discharging drilling water that is exhausted toward the rear end side in the space E and mixed with dust, it does not leak around the drill hole, Moreover, since the bottom of the excavation hole is filled with excavation water, the surrounding rock mass does not collapse due to strength reduction. Furthermore, since the drilling water is also supplied through the water supply path F between the drill pipe P1 and the casing pipe 13 which is the water supply pipe P2, the above-described fresh water having a lower specific gravity than muddy water or the like can be used as the drilling water. The compressed air ejected from the exhaust hole 17A is not required to have a pressure higher than necessary.
  • the exhaust hole 17A is inclined so as to go to the rear end side as it goes to the outer peripheral side of the tool body 1, so that the dust in the space E is compressed by the compressed air exhausted from the exhaust hole 17A.
  • Drilling water can be more reliably discharged to the rear end side.
  • the excavation pipe P1 is inserted into the casing pipe 13 as the water supply pipe P2, and the water supply path F is between the excavation pipe P1 and the casing pipe 13 (water supply pipe P2).
  • the present embodiment can be applied to the foundation pile driving method in which the casing pipe 13 is built in the excavation hole while forming the excavation hole.
  • the drilling water is supplied only to the tip side of the tool body 1 through the water supply channel F. For this reason, it becomes possible to supply the drilling water to the bottom of the drilling hole at the tip of the tool body 1 and discharge the dust while preventing the drilling hole itself from collapsing.
  • the tool body in addition to supplying the drilling pipe P1 into the casing pipe 13 and supplying the drilling water to the water supply path F therebetween, in this embodiment, the tool body attached to the tip of the drilling pipe P1.
  • a plurality of groove portions 6 extending from the front end surface to the rear end side are formed on the outer periphery of the front end portion of one pilot bit 2 at intervals in the circumferential direction, and some of the groove portions 6A communicate with the water supply path F.
  • the remaining groove 6 ⁇ / b> B communicates with the space E through which the drilling water is discharged via the discharge path 7.
  • the tip portions of some of the groove portions 6A and the remaining groove portions 6B communicate with each other through the communication groove 8 formed on the tip surface of the pilot bit 2, so that the tip portions of the pilot bit 2 and the ring bit 3 are planted.
  • the flour produced by the provided excavation tip 9 can be uniformly taken into the communication groove 8 and reliably discharged together with the excavation water.
  • the pilot bit 2 and the ring bit 3 are configured to rotate integrally around the axis O by the close contact between the conical pilot bit side contact surface 5 and the ring bit side contact surface 10. ing. For this reason, between the pilot bit 2 and the ring bit 3, the drilling water is supplied to the drilling hole from a part other than the part of the groove part 6A, or the flour is contained from a part other than the remaining groove part 6B. It is possible to prevent the drilling water from being discharged. As a result, it becomes possible to more reliably discharge the drilling water containing the flour that has been taken in by the communication groove 8 as described above.
  • the front ends of some of the grooves 6A communicating with the water supply path F and the discharge path 7 are provided.
  • the tip of the remaining groove 6B that communicates with the space E via the communication groove 8 is communicated by the communication groove 8, but the pilot bit 2 of the tool body 1 as in the second embodiment shown in FIGS.
  • a hole 18 may be formed as the discharge path 7 on the inner peripheral side of the groove 6 on the outer periphery of the tip, and the hole 18 and the tip of the groove 6 may be communicated by the communication groove 19.
  • the same reference numerals are assigned to the same parts as those of the first embodiment shown in FIGS. 1 to 4, and description thereof is omitted.
  • the plurality of grooves 6 (three also in this embodiment) formed on the outer periphery of the tip end portion of the pilot bit 2 are all the same as some of the grooves 6A of the first embodiment.
  • the pilot bit 2 is opened to the rear end surface of the pilot bit 2 and communicates with the water supply path F between the excavation pipe P1 and the casing pipe 13 (water supply pipe P2).
  • the hole 18 having a circular cross section penetrating from the tip surface of the pilot bit 2 to the inner peripheral portion of the pilot bit 2 is formed at a position away from the axis O on the inner peripheral side of each groove portion 6. ing.
  • the hole 18 extends in parallel with the axis O, the front end side end opens to the front end surface of the pilot bit 2, and the rear end side end opens to the inner peripheral surface of the pilot bit 2.
  • the tip end portions of these hole portions 18 and the tip end portions of the groove portions 6 communicate with each other via a communication groove 19 extending radially in a radial direction with respect to the axis O on a plane perpendicular to the axis O.
  • the large-diameter distal end portion of the exhaust plug 17 accommodated in the inner peripheral portion of the pilot bit 2 has a plurality of (three) notches 17C penetrating the outer periphery of the distal end portion in the direction of the axis O in the circumferential direction. Each is formed between the exhaust holes 17A.
  • the cutting water supplied from the water supply path F flows to the tip end side of the pilot bit 2 of the tool body 1 through each groove portion 6, and then flours while flowing through the communication groove 19. It winds up and reaches the tip of the hole 18, flows from the hole 18 into the inner peripheral portion of the pilot bit 2, and is filled from the notch 17 ⁇ / b> C to the rear end side from the exhaust hole 17 ⁇ / b> A of the exhaust plug 17. Then, the compressed air is exhausted from the exhaust hole 17A, so that the cutting water mixed with the dust is pushed and discharged to the rear end side, and the drilling water mixed with the new dust is discharged from the hole 18. Sucked.
  • the excavation tool of the second embodiment and the excavation method using the excavation tool do not require a vacuum pump or the like as in the first embodiment, and may require high pressure to the compressed air.
  • more cutting water can be supplied to the distal end side of the tool body 1 even if the number of grooves 6 formed in the distal end portion of the pilot bit 2 is the same as that in the first embodiment.
  • the distance in which the cutting water entrained with the flour flows through the communication groove 19 can be shortened, it is also suitable for excavation at high speed.
  • water mixed with flour can be efficiently discharged without using a vacuum pump, so the present invention is suitable for the foundation pile driving method.

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Abstract

This excavation tool is configured in such a manner that: an air delivery pipe is inserted along the inner periphery of an excavation pipe having a front end at which a tool body is disposed; a water supply passage is provided along the outer periphery of the excavation pipe; a discharge passage for discharging cuttings together with excavation water into the space between the excavation pipe and the air delivery pipe is formed in the front end of the tool body; and an air discharge hole open to the space is formed in the front end of the air delivery pipe.

Description

掘削工具および掘削工法Drilling tools and drilling methods
　本発明は、掘削時に生成された繰り粉を工具本体内に取り込んで掘削パイプ内を通して排出するリバースサーキュレーション工法に用いられる掘削工具、および該掘削工具を用いた掘削工法に関する。
　本願は、２０１６年１月２０日に、日本に出願された特願２０１６－００８８７４号に基づき優先権を主張し、その内容をここに援用する。 The present invention relates to an excavation tool used in a reverse circulation method for taking in dusts generated during excavation into a tool body and discharging it through an excavation pipe, and an excavation method using the excavation tool.
This application claims priority based on Japanese Patent Application No. 2016-008874 filed in Japan on January 20, 2016, the contents of which are incorporated herein by reference.
　ケーシングパイプを用いた基礎杭打ち工法においては、一般的に掘削ビット（工具本体）を打撃するのに用いた圧縮空気を掘削ビットの先端から噴出させ、掘削時に岩盤を砕いて生成された土砂である繰り粉を、この圧縮空気によりケーシングパイプと掘削ロッドとの間の空間を通して後端側に排出する。ところが、このような工法を都市部において実施すると、掘削ビットの先端から噴出した圧縮空気が掘削孔の周囲の岩盤に漏れ出て周囲の岩盤の強度を低下させ、場合によっては周囲の岩盤の崩落を招くおそれがある。 In the foundation pile driving method using a casing pipe, the compressed air used to strike the drill bit (tool body) is generally ejected from the tip of the drill bit, and the bedrock is crushed during the excavation. A certain flour is discharged to the rear end side by the compressed air through the space between the casing pipe and the excavating rod. However, when such a construction method is implemented in urban areas, the compressed air ejected from the tip of the excavation bit leaks into the rock surrounding the excavation hole, reducing the strength of the surrounding rock, and in some cases, the surrounding rock collapses. May be incurred.
　このような場合には、ベントナイトを混ぜた泥水を掘削孔に供給して圧縮空気が漏れ出るのを防ぐのが効果的であるが、比重の高い泥水が混ざった繰り粉を排出しなければならないため、噴出させる圧縮空気の圧力も高くしなければならない。そこで、このような工法に用いる掘削工具として、例えば特許文献１には、ケーシングパイプ内を通して清水を搬送水として供給し、この搬送水が混ざった繰り粉を真空ポンプによって吸い上げて排出するようにした掘削工具が提案されている。 In such a case, it is effective to prevent the compressed air from leaking by supplying muddy water mixed with bentonite to the drilling hole, but it is necessary to discharge the flour that is mixed with muddy water with high specific gravity. For this reason, the pressure of the compressed air to be ejected must also be increased. Therefore, as an excavation tool used for such a construction method, for example, Patent Document 1 supplies fresh water as carrier water through the casing pipe, and sucks and discharges the flour that is mixed with the carrier water by a vacuum pump. Drilling tools have been proposed.
特開２００７－１７００８７号公報Japanese Patent Laid-Open No. 2007-170087
　しかしながら、そのような特許文献１に記載された掘削工具では、真空ポンプが必要となるのは勿論のこと、この真空ポンプ内を繰り粉が混ざった搬送水が通過することになるため、真空ポンプに早期に損傷が生じるおそれがあり、長期に亙って安定した掘削を行うことは困難となる。 However, in such an excavation tool described in Patent Document 1, not only a vacuum pump is required, but also the conveying water mixed with the flour passes through the vacuum pump. There is a risk that damage will occur early, making it difficult to perform stable excavation over a long period of time.
　本発明は、このような背景の下になされたもので、真空ポンプを用いることなく、繰り粉が混ざった水を効率的に排出することが可能な掘削工具、および該掘削工具を用いた掘削工法を提供することを目的としている。 The present invention has been made under such a background. An excavation tool capable of efficiently discharging water mixed with flour without using a vacuum pump, and excavation using the excavation tool. The purpose is to provide construction methods.
　上記課題を解決して、このような目的を達成するために、本発明の掘削工具は、先端部に工具本体が配設される掘削パイプの内周に圧縮空気を供給する送気パイプが挿通されるとともに、上記掘削パイプの外周には、上記工具本体の先端部に掘削水を供給する給水路が設けられており、上記工具本体の先端部には、掘削時に生成された繰り粉を上記給水路から供給された上記掘削水とともに上記掘削パイプと上記送気パイプとの間の空間に排出する排出路が形成され、上記送気パイプの先端部には、上記空間に開口する排気孔が形成されていることを特徴とする。 In order to solve the above problems and achieve such an object, the excavation tool of the present invention has an air supply pipe for supplying compressed air to the inner periphery of the excavation pipe in which the tool body is disposed at the tip. In addition, the outer periphery of the excavation pipe is provided with a water supply channel for supplying excavation water to the tip of the tool body, and the tip of the tool body is fed with the flour generated during excavation. A discharge passage is formed in the space between the drilling pipe and the air supply pipe together with the drilling water supplied from the water supply passage, and an exhaust hole opening in the space is formed at the tip of the air supply pipe. It is formed.
　また、本発明の掘削工法は、このような掘削工具を用いて、上記工具本体により掘削孔を形成しつつ、上記給水路を介して上記工具本体の先端部に掘削水を供給し、掘削時に生成された繰り粉を上記掘削水とともに上記排出路を通して上記掘削パイプと上記送気パイプとの間の空間に排出し、この空間に排出された上記繰り粉と掘削水とを、上記排気孔から排気される圧縮空気によって後端側に排出することを特徴とする。 Further, the excavation method of the present invention uses such an excavation tool to supply excavation water to the tip of the tool main body through the water supply channel while forming a excavation hole by the tool main body. The generated dust is discharged together with the drilling water through the discharge passage to a space between the drilling pipe and the air supply pipe, and the dust and drilling water discharged to the space are discharged from the exhaust hole. It is characterized in that it is discharged to the rear end side by compressed air that is exhausted.
　上記構成の掘削工具および該掘削工具を用いた上述のような掘削工法においては、送気パイプの先端部に、掘削パイプとの間の空間に開口する排気孔が形成されており、掘削時には例えば工具本体を打撃するのに用いられた圧縮空気が送気パイプに供給されて排気孔から排気され、掘削パイプと送気パイプとの間の空間に排出された繰り粉と掘削水を、この排気孔から排気された圧縮空気によって後端側に押し出して排出する。 In the excavation tool having the above-described configuration and the excavation method using the excavation tool, an exhaust hole opening in a space between the excavation pipe is formed at the tip of the air supply pipe. The compressed air used to strike the tool body is supplied to the air supply pipe, exhausted from the exhaust hole, and the dust and drilling water discharged into the space between the drilling pipe and the air supply pipe are discharged into the exhaust pipe. The compressed air exhausted from the hole is pushed out to the rear end side and discharged.
　従って、このような掘削工具および掘削工法によれば、こうして工具本体に打撃力を与えるために供給した圧縮空気を繰り粉と掘削水の排出に利用できるとともに、掘削時には給水路を介して掘削水が工具本体の先端部に供給されるので、圧縮空気が掘削孔の周囲の岩盤に漏れ出て強度を低下させることにより崩落を招くのを防ぐことができる。また、掘削水は給水路を介して工具本体の先端部に供給されるので、掘削水として清水を用いることができ、圧縮空気の圧力を必要以上に高くする必要もない。 Therefore, according to such an excavation tool and excavation method, the compressed air thus supplied to give a striking force to the tool body can be used for the dusting and the discharge of the excavation water. Is supplied to the tip of the tool main body, it is possible to prevent the compressed air from leaking into the rock around the excavation hole and reducing the strength, thereby causing collapse. Moreover, since drilling water is supplied to the front-end | tip part of a tool main body via a water supply channel, clear water can be used as drilling water and it is not necessary to make the pressure of compressed air higher than necessary.
　そして、このように圧縮空気を用いて繰り粉と掘削水を掘削パイプと送気パイプとの間の空間の後端側に排出することができるので、真空ポンプを必要とすることなく、真空ポンプ内を繰り粉が通過することによる損傷が生じることもない。また、圧縮空気が排気されて繰り粉と掘削水とが後端側に押し出されると、排気孔よりも先端側の空間は負圧となるので、この空間に工具本体の先端から新たな繰り粉と掘削水を吸引して連続的に排出することができる。 And since the flour and the drilling water can be discharged to the rear end side of the space between the drilling pipe and the air supply pipe using the compressed air in this way, the vacuum pump is not required. There is no damage caused by passing the flour inside. Also, when compressed air is exhausted and dusting and drilling water are pushed out to the rear end side, the space on the tip side from the exhaust hole becomes negative pressure. And the drilling water can be sucked and discharged continuously.
　ここで、上記排気孔を、上記工具本体の外周側に向かうに従い後端側に向かうように傾斜して上記空間に開口するように形成しても良い。これにより、この空間に排出された繰り粉と掘削水とを後端側に押し出して一層確実に排出することができる。さらに、上記構成の掘削工具を、ケーシングパイプを用いた基礎杭打ち工法に適用する場合には、このケーシングパイプを給水パイプとして、上記掘削パイプをこの給水パイプの内周に挿通することにより、上記給水路を上記給水パイプと上記掘削パイプとの間に形成しても良い。これにより、掘削水を確実に工具本体の先端部に供給することが可能となる。 Here, the exhaust hole may be formed so as to incline toward the rear end side toward the outer peripheral side of the tool body and open into the space. Thereby, the flour and drilling water discharged | emitted in this space can be extruded to a rear end side, and can be discharged | emitted more reliably. Furthermore, when the excavation tool having the above configuration is applied to a foundation pile driving method using a casing pipe, the casing pipe is used as a water supply pipe, and the excavation pipe is inserted into the inner periphery of the water supply pipe, thereby A water supply channel may be formed between the water supply pipe and the excavation pipe. Thereby, it becomes possible to supply drilling water to the front-end | tip part of a tool main body reliably.
　また、特にこうしてケーシングパイプを給水パイプとして掘削パイプを挿通した場合には、上記工具本体の先端部外周に、該工具本体の先端から後端側に延びる複数条の溝部を形成して、これら複数条の溝部のうち、一部の溝部は上記給水路に連通させるとともに、残りの溝部は上記排出路に連通させ、上記一部の溝部の先端部と上記残りの溝部の先端部とを、上記工具本体の先端面に形成された連通溝を介して連通させても良い。これにより、一部の溝部から供給された掘削水が連通溝を介して残りの溝部の先端部に流れ込む間に繰り粉を効率的に回収し、上記排出路から掘削パイプと送気パイプとの間の空間に排出することができる。 Further, particularly when the excavation pipe is inserted using the casing pipe as a water supply pipe, a plurality of groove portions extending from the front end of the tool body to the rear end side are formed on the outer periphery of the front end of the tool body. Among the groove portions of the strip, some of the groove portions are communicated with the water supply channel, and the remaining groove portions are communicated with the discharge channel, and the tip portions of the some groove portions and the tip portions of the remaining groove portions are You may communicate through the communicating groove formed in the front end surface of a tool main body. As a result, the dust is efficiently recovered while the drilling water supplied from some of the grooves flows into the tip of the remaining grooves via the communication grooves, and the drilling pipe and the air supply pipe are It can be discharged into the space between.
　一方、上記工具本体の先端部外周に、該工具本体の先端から後端側に延びて上記給水路に連通する溝部を形成するとともに、この溝部よりも内周側の上記工具本体内には、該工具本体の先端から後端側に延びる孔部を上記排出路として形成し、上記溝部の先端部と上記孔部の先端部とを、上記工具本体の先端面に形成された連通溝を介して連通させても良い。このような構成によっても、同様に溝部から供給された掘削水が連通溝を介して孔部の先端部に流れ込む間に繰り粉を効率的に回収することができる。なお、以上の構成を備える掘削工具は本発明の掘削工法に用いることができる。 On the other hand, on the outer periphery of the tip of the tool body, a groove extending from the tip of the tool body to the rear end side and communicating with the water supply channel is formed, and in the tool body on the inner peripheral side of the groove, A hole extending from the front end of the tool body toward the rear end is formed as the discharge path, and the front end of the groove and the front end of the hole are connected via a communication groove formed on the front end surface of the tool body. May be communicated. Even with such a configuration, the dusting can be efficiently recovered while the drilling water supplied from the groove similarly flows into the tip of the hole through the communication groove. In addition, the excavation tool provided with the above structure can be used for the excavation method of the present invention.
　以上説明したように、本発明によれば、掘削孔の周囲の岩盤の強度を低下させて崩落を招くことがなく、また圧縮空気の圧力を必要以上に高くする必要もなく、しかも真空ポンプを必要とすることもないので、安定した掘削を低コストで効率的に行うことができる。 As described above, according to the present invention, the strength of the rock mass around the excavation hole is not lowered and collapse is not caused, and the pressure of the compressed air is not required to be increased more than necessary, and the vacuum pump is provided. Since it is not necessary, stable excavation can be performed efficiently at low cost.
本発明の掘削工具の第１の実施形態を示す側断面図である。It is a sectional side view which shows 1st Embodiment of the excavation tool of this invention. 図１に示す実施形態の工具本体の正面図である。It is a front view of the tool main body of embodiment shown in FIG. 図１に示す実施形態の工具本体におけるシャンク部の背面図である。It is a rear view of the shank part in the tool main body of embodiment shown in FIG. 図１におけるＺＺ断面図である。It is ZZ sectional drawing in FIG. 本発明の掘削工具の第２の実施形態を示す側断面図である。It is a sectional side view which shows 2nd Embodiment of the excavation tool of this invention. 図５に示す実施形態の工具本体の正面図である。It is a front view of the tool main body of embodiment shown in FIG. 図５に示す実施形態の工具本体におけるシャンク部の背面図である。It is a rear view of the shank part in the tool main body of embodiment shown in FIG. 図５におけるＺＺ断面図である。It is ZZ sectional drawing in FIG.
　図１ないし図４は、本発明の掘削工具の第１の実施形態を示す。本実施形態において、工具本体１は、鋼材等の金属材料により形成されて軸線Ｏ方向先端側（図１において左側）が一段大径とされた軸線Ｏを中心とする有底の略多段円筒状のパイロットビット２と、このパイロットビット２の先端部外周に着脱可能に取り付けられる同じく鋼材等の金属材料により軸線Ｏを中心とした円環状または円筒状に形成されたリングビット３とを備えている。パイロットビット２の小径の後端部は外周に雄ネジ部が形成されたシャンク部２Ａとされ、このシャンク部２Ａに円筒状の掘削パイプＰ１がシャンク部２Ａの雄ネジ部と螺合することにより取り付けられる。該掘削パイプＰ１を介してパイロットビット２には軸線Ｏ回りの回転力と軸線Ｏ方向先端側への推力および打撃力とが与えられる。なお、本明細書においては、軸線Ｏの延びる方向を軸線Ｏ方向といい、軸線Ｏ方向のうち、掘削パイプＰ１からパイロットビット２へ向かう方向を先端側（図１の左側）といい、パイロットビット２から掘削パイプＰ１へ向かう方向を後端側（図１の右側）という。また、軸線Ｏを通り軸線Ｏに直交する方向を径方向又は半径方向という。径方向のうち軸線Ｏに接近する方向（径方向内方）を内周側といい、軸線Ｏから離間する方向（径方向外方）を外周側という。さらに、軸線Ｏ回りに周回する方向を周方向という。 1 to 4 show a first embodiment of the excavation tool of the present invention. In the present embodiment, the tool body 1 is formed of a metal material such as a steel material, and has a substantially multi-stage cylindrical shape with a bottom centered on an axis O whose front end side in the axis O direction (left side in FIG. 1) has a one-step large diameter. Of the pilot bit 2 and a ring bit 3 formed in an annular shape or a cylindrical shape around the axis O by a metal material such as steel that is detachably attached to the outer periphery of the tip end portion of the pilot bit 2. . The rear end portion of the pilot bit 2 having a small diameter is a shank portion 2A having a male screw portion formed on the outer periphery, and a cylindrical excavation pipe P1 is screwed into the shank portion 2A with the male screw portion of the shank portion 2A. It is attached. Through the excavation pipe P1, the pilot bit 2 is given a rotational force around the axis O, and a thrust and striking force toward the tip side in the direction of the axis O. In this specification, the direction in which the axis O extends is referred to as the axis O direction, and the direction from the excavation pipe P1 to the pilot bit 2 in the axis O direction is referred to as the tip side (left side in FIG. 1). A direction from 2 to the excavation pipe P1 is referred to as a rear end side (right side in FIG. 1). A direction passing through the axis O and orthogonal to the axis O is referred to as a radial direction or a radial direction. Of the radial directions, the direction approaching the axis O (inward in the radial direction) is referred to as the inner peripheral side, and the direction away from the axis O (outward in the radial direction) is referred to as the outer peripheral side. Furthermore, a direction that circulates around the axis O is referred to as a circumferential direction.
　本実施形態では、このシャンク部２Ａよりも先端側のパイロットビット２の先端部は、先端側に向けて概ね３段に縮径するように形成されている。すなわち、パイロットビット２の先端部は、後端側から順に、外径が最大の大径部２Ｂと、大径部２Ｂより外径が小さい中径部２Ｃと、中径部２Ｃより外径が小さい小径部２Ｄとを有している。このうち最も後端側に位置する大径部２Ｂの外周面とその次の中径部２Ｃの外周面との間には、軸線Ｏ方向先端側に向かうに従い漸次縮径する軸線Ｏを中心とした円錐面状のパイロットビット側当接面４が形成される。中径部２Ｃの外周面と最先端の小径部２Ｄの外周面との間に、軸線Ｏ方向先端側に向かうに従い漸次縮径する軸線Ｏを中心とした円錐面状のパイロットビット側接触面５が形成されている。 In the present embodiment, the tip portion of the pilot bit 2 on the tip side of the shank portion 2A is formed so as to be reduced in diameter to approximately three steps toward the tip side. That is, the front end portion of the pilot bit 2 has, in order from the rear end side, a large diameter portion 2B having the largest outer diameter, a medium diameter portion 2C having an outer diameter smaller than that of the large diameter portion 2B, and an outer diameter smaller than that of the medium diameter portion 2C. A small small-diameter portion 2D. Among these, between the outer peripheral surface of the large-diameter portion 2B located on the most rear end side and the outer peripheral surface of the next medium-diameter portion 2C, the axis O gradually decreases toward the front end side in the axis O direction. The pilot bit side contact surface 4 having a conical surface is formed. A conical pilot bit side contact surface 5 centering on the axis O that gradually decreases in diameter toward the tip end in the direction of the axis O between the outer peripheral surface of the medium diameter portion 2C and the outer peripheral surface of the most advanced small diameter portion 2D. Is formed.
　ここで、図１に示すように軸線Ｏに沿った断面において、上記パイロットビット側当接面４が該軸線Ｏに対してなす傾斜角αよりも、パイロットビット側接触面５が該軸線Ｏに対してなす傾斜角βが小さく設定されている。本実施形態では、図１に示すように、パイロットビット側当接面４では、軸線Ｏに平行な方向の長さＡが、この長さＡ分だけ軸線Ｏ方向先端側に向かったときに縮径する半径（半径の減少量）Ｂ以下となるように形成され、すなわち軸線Ｏに対してなす傾斜角αが４５°以上となるように形成されている。これとは逆に、パイロットビット側接触面５では、軸線Ｏに平行な方向の長さＣが、この長さＣ分だけ軸線Ｏ方向先端側に向かったときに縮径する半径（半径の減少量）Ｄよりも長くなるように形成されていて、軸線Ｏに対してなす傾斜角βが４５°未満とされている。 Here, in the cross section along the axis O as shown in FIG. 1, the pilot bit side contact surface 5 is closer to the axis O than the inclination angle α formed by the pilot bit side contact surface 4 with respect to the axis O. In contrast, the inclination angle β is set small. In the present embodiment, as shown in FIG. 1, the length A in the direction parallel to the axis O on the pilot bit side contact surface 4 is reduced when the length A is directed toward the tip side in the axis O direction. It is formed so as to be equal to or less than the radius (the amount of decrease in radius) B, that is, the inclination angle α formed with respect to the axis O is 45 ° or more. On the other hand, the pilot bit side contact surface 5 has a radius (a decrease in radius) that reduces the length C in the direction parallel to the axis O toward the tip side in the direction of the axis O by the length C. The angle β formed with respect to the axis O is less than 45 °.
　なお、パイロットビット側接触面５の上記長さＣは、パイロットビット側当接面４の上記長さＢよりも十分に長く、パイロットビット側接触面５の上記半径Ｄは、パイロットビット側当接面４の上記半径Ｂよりも僅かに大きくなるように設定されている。また、上記大径部２Ｂ、中径部２Ｃ、および小径部２Ｄの外周面は、それぞれ軸線Ｏを中心とした一定の外径の円筒面とされており、このうち中径部２Ｃの軸線Ｏ方向の長さは、大径部２Ｂや小径部２Ｄよりも僅かに長く設定されている。 The length C of the pilot bit side contact surface 5 is sufficiently longer than the length B of the pilot bit side contact surface 4, and the radius D of the pilot bit side contact surface 5 is equal to the pilot bit side contact surface 5. It is set to be slightly larger than the radius B of the surface 4. The outer peripheral surfaces of the large-diameter portion 2B, the medium-diameter portion 2C, and the small-diameter portion 2D are cylindrical surfaces having a constant outer diameter centered on the axis O, and of these, the axis O of the medium-diameter portion 2C. The length in the direction is set slightly longer than the large diameter portion 2B and the small diameter portion 2D.
　さらに、このパイロットビット２の先端部外周には、パイロットビット２の先端面から後端側に延びる溝部６が周方向に略等間隔に複数条（本実施形態では３条）形成されている。これら複数条の溝部６のうち、一部の溝部（図１において上側、図２において左側の１つの溝部）６Ａは、パイロットビット２の先端面から上記大径部２Ｂの後端面に貫通している。複数条の溝部６のうち残りの溝部（図１において下側、図２において右側の２つの溝部）６Ｂは、パイロットビット２の先端面から大径部２Ｂの手前まで延びて外周側に切れ上がっている。言い換えると、残りの溝部６Ｂは、パイロットビット２の先端面から中径部２Ｃのうち中径部２Ｃの後端近傍まで延びる。この残りの溝部６Ｂが切れ上がった後端部からは、本実施形態における排出路７として内周側に向かうに従い後端側に向かう断面円形の孔部が形成されている。この孔部の一端は有底円筒状のパイロットビット２の内周部（内周面）に開口し、他端が残りの溝部６Ｂの後端部に開口している。 Further, on the outer periphery of the front end of the pilot bit 2, a plurality of grooves 6 (three in the present embodiment) are formed at substantially equal intervals in the circumferential direction extending from the front end surface of the pilot bit 2 to the rear end. Among the plurality of groove portions 6, a part of the groove portions (one groove portion on the upper side in FIG. 1 and one groove on the left side in FIG. 2) 6 </ b> A penetrates from the front end surface of the pilot bit 2 to the rear end surface of the large diameter portion 2 </ b> B. Yes. Among the plurality of groove portions 6, the remaining groove portions (the two groove portions on the lower side in FIG. 1 and the right side in FIG. 2) 6B extend from the front end surface of the pilot bit 2 to the front of the large-diameter portion 2B and cut off to the outer peripheral side. ing. In other words, the remaining groove 6B extends from the front end surface of the pilot bit 2 to the vicinity of the rear end of the medium diameter part 2C in the medium diameter part 2C. From the rear end portion where the remaining groove portion 6B is cut off, a hole having a circular cross-section toward the rear end side is formed as the discharge path 7 in the present embodiment toward the inner peripheral side. One end of this hole portion opens to the inner peripheral portion (inner peripheral surface) of the bottomed cylindrical pilot bit 2, and the other end opens to the rear end portion of the remaining groove portion 6B.
　また、パイロットビット２の先端面には、上記一部の溝部６Ａの先端部と残りの溝部６Ｂの先端部とを結んで連通する連通溝８が形成されている。この連通溝８は、本実施形態では正面視において図２に示すように、一部の溝部６Ａの先端部から軸線Ｏに対する半径方向に該軸線Ｏの手前にまで延びた後、軸線Ｏには達することなく２つに分岐して湾曲しながら２つの残りの溝部６Ｂの先端部に達するＹ字状に形成されている。なお、溝部６は断面略方形状または略Ｕ字状をなしていて、その外周側を向く底面は図１に示すように後端側に向かうに従い外周側に向かうように軸線Ｏに対し僅かに傾斜している。連通溝８は図４に示すように断面Ｕ字状をなして軸線Ｏに垂直な平面上に延びている。 In addition, a communication groove 8 is formed on the front end surface of the pilot bit 2 to connect the front end of the partial groove 6A and the front end of the remaining groove 6B. In this embodiment, the communication groove 8 extends from the front end of a part of the groove 6A in the radial direction with respect to the axis O to the front of the axis O as shown in FIG. It is formed in a Y-shape that reaches the leading ends of the two remaining grooves 6B while branching and curving in two without reaching. The groove portion 6 has a substantially square or substantially U-shaped cross section, and the bottom surface facing the outer peripheral side is slightly with respect to the axis O so as to go to the outer peripheral side toward the rear end side as shown in FIG. It is inclined. As shown in FIG. 4, the communication groove 8 has a U-shaped cross section and extends on a plane perpendicular to the axis O.
　さらに、パイロットビット２の先端面には、上記溝部６の開口部と連通溝８を除いて軸線Ｏに垂直な平面状をなす中央部のフェイス面と、後端側に向かうに従い外周側に向かうように傾斜する円錐面状の外周部のゲージ面とが形成されている。これらフェイス面とゲージ面には、溝部６の開口部と連通溝８を避けるようにして、パイロットビット２よりも硬質な超硬合金等からなる掘削チップ９がフェイス面およびゲージ面に垂直に植設されている。 Further, on the front end surface of the pilot bit 2, except for the opening portion of the groove portion 6 and the communication groove 8, a central face surface that is perpendicular to the axis O and toward the outer peripheral side toward the rear end side. Thus, a conical surface-shaped outer peripheral gauge surface is formed. On these face surface and gauge surface, an excavation tip 9 made of cemented carbide harder than the pilot bit 2 is implanted perpendicularly to the face surface and gauge surface so as to avoid the opening of the groove portion 6 and the communication groove 8. It is installed.
　さらにまた、パイロットビット２の上記小径部２Ｄの外周面には、外周側に突出する軸線Ｏを中心とした円弧板状の（軸線Ｏを中心とした弧面である外周面を有する）突条部２Ｅが、パイロットビット側接触面５から先端側に僅かな間隔をあけて離れた位置に、周方向に等間隔に複数条（本実施形態では３条）形成されている。これらの突条部２Ｅは、本実施形態では上記溝部６の周方向の一端（図２に示すように正面視において反時計回り方向の端部）から延びており、ゲージ面の掘削チップ９は、この突条部２Ｅに亙って植設されている。 Furthermore, the outer peripheral surface of the small-diameter portion 2D of the pilot bit 2 has an arc plate-shaped protrusion (having an outer peripheral surface that is an arc surface centered on the axis O) centered on the axis O protruding outward. The section 2E is formed with a plurality of strips (three strips in the present embodiment) at equal intervals in the circumferential direction at positions spaced apart from the pilot bit side contact surface 5 by a slight distance. In the present embodiment, these protrusions 2E extend from one end in the circumferential direction of the groove 6 (the end in the counterclockwise direction when viewed from the front as shown in FIG. 2). It is planted over the ridge 2E.
　このようなパイロットビット２の外周に取り付けられる円環状または円筒状の上記リングビット３には、その後端部の内周面に、軸線Ｏ方向先端側に向かうに従い漸次縮径する軸線Ｏを中心とした円錐面状のリングビット側接触面１０が形成されている。このリングビット側接触面１０は、軸線Ｏに沿った断面において、該軸線Ｏに対してパイロットビット側接触面５と等しい傾斜角βをなしている。 In the annular or cylindrical ring bit 3 attached to the outer periphery of the pilot bit 2, the axial line O is gradually reduced in diameter toward the front end side in the axis O direction on the inner peripheral surface of the rear end portion. A conical ring-shaped ring bit side contact surface 10 is formed. The ring bit side contact surface 10 has an inclination angle β equal to the pilot bit side contact surface 5 with respect to the axis O in a cross section along the axis O.
　すなわち、リングビット側接触面１０は、パイロットビット側接触面５と同じく軸線Ｏに平行な方向の長さＣが、この長さＣ分だけ軸線Ｏ方向先端側に向かったときに縮径する半径Ｄよりも長くなるように形成されて、軸線Ｏに対して４５°未満の傾斜角βに形成されている。このようなリングビット３は、図１に示すようにこのリングビット側接触面１０をパイロットビット側接触面５に密着させ、軸線Ｏ方向にパイロットビット２の先端面からパイロットビット側接触面５の後端に亙って取り付けられる。言い換えると、本実施形態では、軸線Ｏ方向におけるリングビット３の長さはパイロットビット２の先端面からパイロットビット側接触面５の後端までの軸線Ｏ方向における長さと略同一である。そして、軸線Ｏ方向において、リングビット３の先端面の位置がパイロットビット２の先端面と略同一となるように、リングビット３がパイロットビット２の外周に取り付けられている。 That is, the ring bit side contact surface 10 has a radius that decreases when the length C in the direction parallel to the axis O is the same as the pilot bit side contact surface 5 toward the tip side in the axis O direction by this length C. It is formed so as to be longer than D, and is formed at an inclination angle β of less than 45 ° with respect to the axis O. 1, the ring bit side contact surface 10 is brought into close contact with the pilot bit side contact surface 5 as shown in FIG. 1, and the pilot bit side contact surface 5 extends from the front end surface of the pilot bit 2 in the axis O direction. Installed over the rear edge. In other words, in the present embodiment, the length of the ring bit 3 in the axis O direction is substantially the same as the length in the axis O direction from the front end surface of the pilot bit 2 to the rear end of the pilot bit side contact surface 5. The ring bit 3 is attached to the outer periphery of the pilot bit 2 so that the position of the tip surface of the ring bit 3 is substantially the same as the tip surface of the pilot bit 2 in the direction of the axis O.
　また、リングビット３の先端部の内周面は、パイロットビット２の小径部２Ｄよりも僅かに大きな内径を有している。この先端部の内周面には、パイロットビット２の突条部２Ｅよりも周方向に僅かに幅広の凹溝部３Ａが、周方向に等間隔に突条部２Ｅと同数、軸線Ｏ方向にリングビット３の先端面から上記リングビット側接触面１０に向けて貫通するように形成されている。凹溝部３Ａの径方向の深さは、凹溝部３Ａの内径が突条部２Ｅの外径よりも僅かに大きくなるように設定されている。 Further, the inner peripheral surface of the tip portion of the ring bit 3 has an inner diameter slightly larger than the small diameter portion 2D of the pilot bit 2. On the inner peripheral surface of the tip, there are concave grooves 3A that are slightly wider in the circumferential direction than the ridges 2E of the pilot bit 2. The same number as the ridges 2E at equal intervals in the circumferential direction and ring in the direction of the axis O It is formed so as to penetrate from the tip surface of the bit 3 toward the ring bit side contact surface 10. The depth in the radial direction of the groove 3A is set so that the inner diameter of the groove 3A is slightly larger than the outer diameter of the protrusion 2E.
　さらに、この凹溝部３Ａの周方向の一端（パイロットビット２の突条部２Ｅが溝部６から周方向に延びる端部と同じ方向の端部、すなわち図２における反時計回り方向の端部）からは、径方向の深さが凹溝部３Ａと等しく、軸線Ｏ方向の長さが突条部２Ｅよりも僅かに長い軸線Ｏ方向に沿った断面がＬ字状の係合部３Ｂが形成されている。係合部３Ｂの内周面は、その先端側において凹溝部３Ａの内周面と周方向に滑らかに連続している。凹溝部３Ａに突条部２Ｅを収容してリングビット３をパイロットビット２の先端の先端側から挿入し、パイロットビット２を上記周方向の一端側（図２における反時計回り方向）に回転させることにより、突条部２Ｅが係合部３Ｂに嵌合して係合可能とされている。従って、こうして突条部２Ｅが係合部３Ｂに嵌合した状態で、パイロットビット２の溝部６の位置はリングビット３の凹溝部３Ａと周方向に一致する。なお、係合部３Ｂの周方向幅は、突条部２Ｅが係合部３Ｂに嵌合した状態で、周方向においてパイロットビット２の溝部６の位置がリングビット３の凹溝部３Ａと重複するように設定される。本実施形態においては、係合部３Ｂの周方向幅を突条部２Ｅの周方向幅と同程度となるように設定している。 Further, from one end in the circumferential direction of the recessed groove portion 3A (the end portion in the same direction as the end portion where the protrusion 2E of the pilot bit 2 extends in the circumferential direction from the groove portion 6, that is, the end portion in the counterclockwise direction in FIG. 2). Is formed with an engagement portion 3B having an L-shaped cross section along the axis O direction in which the depth in the radial direction is equal to the concave groove portion 3A and the length in the axis O direction is slightly longer than the protrusion 2E. Yes. The inner peripheral surface of the engaging portion 3B is smoothly continuous with the inner peripheral surface of the recessed groove portion 3A in the circumferential direction on the tip side. The protrusion 2E is accommodated in the concave groove 3A, the ring bit 3 is inserted from the tip side of the tip of the pilot bit 2, and the pilot bit 2 is rotated to one end side in the circumferential direction (counterclockwise direction in FIG. 2). Thus, the protruding portion 2E is engaged with the engaging portion 3B. Therefore, the position of the groove portion 6 of the pilot bit 2 coincides with the concave groove portion 3A of the ring bit 3 in the circumferential direction in a state where the protruding portion 2E is fitted to the engaging portion 3B. The circumferential width of the engaging portion 3B is such that the position of the groove portion 6 of the pilot bit 2 overlaps with the concave groove portion 3A of the ring bit 3 in the circumferential direction in a state where the protruding portion 2E is fitted to the engaging portion 3B. Is set as follows. In the present embodiment, the circumferential width of the engaging portion 3B is set to be approximately the same as the circumferential width of the protrusion 2E.
　さらに、このリングビット３の先端面も、軸線Ｏに垂直な内周部のフェイス面と、後端側に向かうに従い外周側に向かうように傾斜する外周部のゲージ面とを備えている。これらフェイス面とゲージ面には、リングビット３よりも硬質な超硬合金等からなる掘削チップ９がフェイス面とゲージ面に垂直に植設されている。なお、リングビット３の先端部の外周面には、ゲージ面に植設された掘削チップ９の間に複数の凹溝３Ｃが周方向に等間隔に形成されている。 Furthermore, the front end surface of the ring bit 3 also includes an inner peripheral face surface perpendicular to the axis O, and an outer peripheral gauge surface that inclines toward the outer peripheral side toward the rear end side. On these face surface and gauge surface, a drilling tip 9 made of a cemented carbide harder than the ring bit 3 is implanted perpendicularly to the face surface and gauge surface. A plurality of concave grooves 3C are formed at equal intervals in the circumferential direction between the excavation tips 9 planted on the gauge surface on the outer peripheral surface of the tip portion of the ring bit 3.
　一方、リングビット３の外周面には、その先端面のゲージ面と後端面とから軸線Ｏ方向に間隔をあけた位置に、軸線Ｏに沿った断面が軸線Ｏ方向に延びる長方形状をなして外周側に開口するリングビット側係止溝１１が全周に亙って形成されている。また、このリングビット側係止溝１１よりも後端側のリングビット３の外周部は、リングビット側係止溝１１に対して外周側に突出した環状のリングビット側係止部１２とされている。リングビット側係止部１２の外径はリングビット３の先端部よりも小径とされ、また軸線Ｏ方向の長さはリングビット側係止溝１１より短く設定されている。なお、このリングビット側係止部１２の後端外周部には面取りが施されている。 On the other hand, the outer peripheral surface of the ring bit 3 has a rectangular shape with a cross section along the axis O extending in the axis O direction at a position spaced from the gauge surface and the rear end surface of the front end surface in the axis O direction. A ring bit side locking groove 11 opened to the outer peripheral side is formed over the entire periphery. Further, the outer peripheral portion of the ring bit 3 on the rear end side of the ring bit side locking groove 11 is an annular ring bit side locking portion 12 that protrudes toward the outer peripheral side with respect to the ring bit side locking groove 11. ing. The outer diameter of the ring bit side locking portion 12 is smaller than the tip of the ring bit 3, and the length in the direction of the axis O is set shorter than the ring bit side locking groove 11. Note that the outer peripheral portion of the rear end of the ring bit side locking portion 12 is chamfered.
　さらに、本実施形態では、上述のようにリングビット３が取り付けられたパイロットビット２の外周に、本実施形態における給水パイプＰ２として軸線Ｏを中心とする円筒状のケーシングパイプ１３が配設されている。掘削パイプＰ１外周のケーシングパイプ１３（給水パイプＰ２）との間には給水路Ｆが形成される。ケーシングパイプ１３は、軸線Ｏを中心とする円筒状のパイプ本体１３Ａの先端部に、同じく軸線Ｏを中心とする円筒状のケーシングトップ１３Ｂが溶接等により接合されて一体化されたものである。パイプ本体１３Ａはパイロットビット２の大径部２Ｂの外径よりも大きな内径を有していて、掘削孔の深さに応じて複数のパイプ本体１３Ａがパイプ本体１３Ａの後端側に溶接等により順次継ぎ足されてゆく。 Further, in the present embodiment, a cylindrical casing pipe 13 centering on the axis O is disposed as the water supply pipe P2 in the present embodiment on the outer periphery of the pilot bit 2 to which the ring bit 3 is attached as described above. Yes. A water supply path F is formed between the outer periphery of the excavation pipe P1 and the casing pipe 13 (water supply pipe P2). The casing pipe 13 is obtained by integrating a cylindrical casing top 13B, which is also centered on the axis O, with a tip end portion of a cylindrical pipe body 13A centering on the axis O by welding or the like. The pipe body 13A has an inner diameter larger than the outer diameter of the large-diameter portion 2B of the pilot bit 2, and a plurality of pipe bodies 13A are welded or the like to the rear end side of the pipe body 13A according to the depth of the drilling hole. It will be added sequentially.
　ケーシングトップ１３Ｂは、その後端部の外径が先端部よりも一段小さく形成されていて、その段差部に最先端のパイプ本体１３Ａの先端部が嵌め入れられて接合されている。言い換えると、ケーシングトップ１３Ｂの後端部の外径が、パイプ本体１３Ａの先端部の内径と略同一となっており、ケーシングトップ１３Ｂの後端部がパイプ本体１３Ａと嵌合して接合されている。また、このケーシングトップ１３Ｂの後端部の内径は、パイロットビット２の大径部２Ｂの外径よりも僅かに小さく、中径部２Ｃの外径よりは僅かに大きく設定されている。そして、ケーシングトップ１３Ｂの後端面の内周部には、パイロットビット２のパイロットビット側接触面５よりも後端側に形成された上記パイロットビット側当接面４と互いに当接可能なケーシングパイプ側当接面１４が形成されている。 The casing top 13B is formed so that the outer diameter of the rear end portion thereof is one step smaller than that of the tip end portion, and the tip end portion of the most advanced pipe body 13A is fitted and joined to the step portion. In other words, the outer diameter of the rear end portion of the casing top 13B is substantially the same as the inner diameter of the front end portion of the pipe body 13A, and the rear end portion of the casing top 13B is fitted and joined to the pipe body 13A. Yes. Further, the inner diameter of the rear end portion of the casing top 13B is set to be slightly smaller than the outer diameter of the large diameter portion 2B of the pilot bit 2 and slightly larger than the outer diameter of the medium diameter portion 2C. A casing pipe that can be brought into contact with the pilot bit side contact surface 4 formed on the rear end side of the pilot bit side contact surface 5 of the pilot bit 2 on the inner peripheral portion of the rear end surface of the casing top 13B. A side contact surface 14 is formed.
　すなわち、このケーシングパイプ側当接面１４も、軸線Ｏ方向先端側に向かうに従い漸次縮径する軸線Ｏを中心とした円錐面状に形成されている。図１に示したように軸線Ｏに沿った断面において、軸線Ｏに対してなす傾斜角αは、パイロットビット側当接面４の傾斜角αと等しく、パイロットビット側接触面５とリングビット側接触面１０がなす傾斜角βよりも大きな角度とされている。さらに、本実施形態では、このケーシングパイプ側当接面１４の軸線Ｏに沿った断面における軸線Ｏに平行な方向の長さＡが、この長さＡ分だけ軸線Ｏ方向先端側に向かったときに縮径する半径Ｂ以下となるように形成されていて、上記傾斜角αは４５°以上とされている。 That is, the casing pipe side contact surface 14 is also formed in a conical surface shape with the axis O gradually decreasing in diameter toward the tip end side in the axis O direction. As shown in FIG. 1, in the cross section along the axis O, the inclination angle α formed with respect to the axis O is equal to the inclination angle α of the pilot bit side contact surface 4, and the pilot bit side contact surface 5 and the ring bit side The angle is larger than the inclination angle β formed by the contact surface 10. Furthermore, in this embodiment, when the length A in the direction parallel to the axis O in the cross section along the axis O of the casing pipe side contact surface 14 is directed to the tip side in the axis O direction by this length A. The inclination angle α is set to 45 ° or more.
　また、ケーシングトップ１３Ｂの先端部の外径は、パイプ本体１３Ａの外径と等しく設定されるとともに、リングビット３の最大外径となる先端部の外径よりは小さく設定されている。このケーシングトップ１３Ｂの先端内周部には先端側に向けて順に、軸線Ｏに沿った断面が軸線Ｏ方向に延びる長方形状をなして内周側に開口するケーシングパイプ側係止溝１５と、このケーシングパイプ側係止溝１５に対して内周側に突出したケーシングパイプ側係止部１６とが、全周に亙って形成されている。 Also, the outer diameter of the tip of the casing top 13B is set equal to the outer diameter of the pipe body 13A, and is set smaller than the outer diameter of the tip that is the maximum outer diameter of the ring bit 3. A casing pipe-side locking groove 15 that opens inward on the inner peripheral side of the casing top 13 </ b> B in a rectangular shape with a cross section along the axis O extending in the direction of the axis O in order toward the tip. A casing pipe side latching portion 16 that protrudes inward from the casing pipe side latching groove 15 is formed over the entire circumference.
　これらケーシングパイプ側係止溝１５およびケーシングパイプ側係止部１６は、軸線Ｏ方向の長さがリングビット側係止溝１１およびリングビット側係止部１２とそれぞれ等しく設定されている。ケーシングパイプ側係止溝１５の内径はリングビット側係止部１２の外径よりも僅かに大きく設定されている。また、ケーシングパイプ側係止部１６の内径は、リングビット側係止溝１１の外径より僅かに大きく、リングビット側係止部１２の外径よりは小さく設定され、その先端内周部には面取りが施されている。 The casing pipe side locking groove 15 and the casing pipe side locking portion 16 are set to have the same length in the axis O direction as the ring bit side locking groove 11 and the ring bit side locking portion 12, respectively. The inner diameter of the casing pipe side locking groove 15 is set to be slightly larger than the outer diameter of the ring bit side locking portion 12. The inner diameter of the casing pipe side locking portion 16 is set to be slightly larger than the outer diameter of the ring bit side locking groove 11 and smaller than the outer diameter of the ring bit side locking portion 12, Has been chamfered.
　リングビット側係止溝１１にケーシングパイプ側係止部１６を収容するとともに、リングビット側係止部１２をケーシングパイプ側係止溝１５に収容させることにより、リングビット３は、軸線Ｏ回りに回転自在、かつリングビット側係止溝１１とケーシングパイプ側係止溝１５が形成された範囲で軸線Ｏ方向先端側と後端側にも係止された状態で、ケーシングトップ１３Ｂに取り付けられる。 By accommodating the casing pipe side latching portion 16 in the ring bit side latching groove 11 and accommodating the ring bit side latching portion 12 in the casing pipe side latching groove 15, the ring bit 3 is rotated around the axis O. It is attached to the casing top 13B in a state that it is freely rotatable and is also locked to the front end side and the rear end side in the axis O direction within a range in which the ring bit side locking groove 11 and the casing pipe side locking groove 15 are formed.
　なお、このようにケーシングトップ１３Ｂにリングビット３を取り付けるには、例えばリングビット側係止部１２の後端外周部とケーシングパイプ側係止部１６の先端内周部の面取りされた部分を互いに一致させた（当接させた）上で、ケーシングトップ１３Ｂとリングビット３の少なくとも一方を軸線Ｏ方向に他方に向かって押圧することにより、リングビット３の後端部を弾性的に縮径させるとともにケーシングトップ１３Ｂの先端部を弾性的に拡径させて、ケーシングパイプ側係止部１６をリングビット側係止溝１１に、リングビット側係止部１２をケーシングパイプ側係止溝１５に、それぞれ嵌め入れるように収容すればよい。こうしてリングビット３が取り付けられた後に、ケーシングトップ１３Ｂがパイプ本体１３Ａに接合されてケーシングパイプ１３の先端部にリングビット３が配設される。 In order to attach the ring bit 3 to the casing top 13B in this way, for example, the chamfered portions of the rear end outer peripheral portion of the ring bit side locking portion 12 and the front end inner peripheral portion of the casing pipe side locking portion 16 are mutually connected. After matching (abutting), the rear end portion of the ring bit 3 is elastically reduced in diameter by pressing at least one of the casing top 13B and the ring bit 3 in the direction of the axis O toward the other. In addition, the tip end portion of the casing top 13B is elastically expanded so that the casing pipe side locking portion 16 is in the ring bit side locking groove 11 and the ring bit side locking portion 12 is in the casing pipe side locking groove 15. What is necessary is just to accommodate so that it may each fit. After the ring bit 3 is attached in this way, the casing top 13B is joined to the pipe body 13A, and the ring bit 3 is disposed at the tip of the casing pipe 13.
　このようにケーシングパイプ１３先端部のケーシングトップ１３Ｂにリングビット３を配設した後、掘削パイプＰ１の先端部に取り付けられたパイロットビット２を、ケーシングパイプ１３内に後端側から挿入し、上述のように凹溝部３Ａに突条部２Ｅを収容してからパイロットビット２を上記周方向の一端側に回転させることにより、突条部２Ｅを係合部３Ｂに嵌合して係合させる。掘削パイプＰ１も掘削孔の深さに応じて順次継ぎ足されて連結され、最後端の掘削パイプＰ１は掘削装置に連結される。こうしてケーシングパイプ１３に挿入されたパイロットビット２は、そのパイロットビット側当接面４がケーシングトップ１３Ｂのケーシングパイプ側当接面１４に当接したところで位置決めされる。 After arranging the ring bit 3 on the casing top 13B at the front end of the casing pipe 13 in this way, the pilot bit 2 attached to the front end of the excavation pipe P1 is inserted into the casing pipe 13 from the rear end side, and As described above, the protrusion 2E is accommodated in the concave groove 3A, and then the pilot bit 2 is rotated to one end side in the circumferential direction, so that the protrusion 2E is fitted and engaged with the engaging portion 3B. The excavation pipe P1 is also added and connected sequentially according to the depth of the excavation hole, and the excavation pipe P1 at the end is connected to the excavator. The pilot bit 2 thus inserted into the casing pipe 13 is positioned when the pilot bit side contact surface 4 contacts the casing pipe side contact surface 14 of the casing top 13B.
　さらに、この状態からパイロットビット２とリングビット３の先端部を岩盤等に当接させて、掘削パイプＰ１を介してパイロットビット２に上記掘削装置から軸線Ｏ回りの回転力と軸線Ｏ方向先端側への推力および打撃力を与えて掘削を行うと、岩盤等からの抵抗によってリングビット３が後端側に押し付けられ、そのリングビット側接触面１０がパイロットビット側接触面５に密着する。なお、掘削前にリングビット３を後端側に押圧してリングビット側接触面１０をパイロットビット側接触面５に密着させておいてもよい。 Further, from this state, the tip portions of the pilot bit 2 and the ring bit 3 are brought into contact with the bedrock and the like, and the rotational force around the axis O and the tip side in the axis O direction from the excavator to the pilot bit 2 via the excavation pipe P1. When excavation is performed by applying thrust and striking force to the ring, the ring bit 3 is pressed against the rear end side by resistance from the rock or the like, and the ring bit side contact surface 10 comes into close contact with the pilot bit side contact surface 5. The ring bit 3 may be pressed to the rear end side before excavation so that the ring bit side contact surface 10 is in close contact with the pilot bit side contact surface 5.
　ここで、リングビット側係止部１２とケーシングパイプ側係止部１６とは、こうしてパイロットビット側当接面４がケーシングパイプ側当接面１４に当接するとともに、リングビット側接触面１０がパイロットビット側接触面５に密着した状態で、図１に示したようにそれぞれケーシングパイプ側係止溝１５とリングビット側係止溝１１との軸線Ｏ方向の両端から間隔をあけた位置に配設されるように形成されている。 Here, the ring bit side latching portion 12 and the casing pipe side latching portion 16 are configured such that the pilot bit side contact surface 4 contacts the casing pipe side contact surface 14 and the ring bit side contact surface 10 functions as the pilot. As shown in FIG. 1, in close contact with the bit side contact surface 5, the casing pipe side locking groove 15 and the ring bit side locking groove 11 are arranged at positions spaced from both ends in the axis O direction. It is formed to be.
　そして、円筒状の掘削パイプＰ１の内周には、後端側から送気パイプＰ３が挿通されて、送気パイプＰ３の先端部が工具本体１におけるパイロットビット２の内周部に挿入されている。さらにこの送気パイプＰ３の先端部には排気プラグ１７が取り付けられて、排気プラグ１７がパイロットビット２の内周部に収容されている。送気パイプＰ３は、掘削パイプＰ１の内径よりも小さな外径を有する軸線Ｏを中心とした円筒状に形成され、この送気パイプＰ３と掘削パイプＰ１との間には、断面円環状の空間Ｅが形成される。送気パイプＰ３の内周部には、例えば上述のようにパイロットビット２に打撃力を与える際のエアハンマーの駆動に用いた圧縮空気が供給される。 The air supply pipe P3 is inserted from the rear end side into the inner periphery of the cylindrical excavation pipe P1, and the tip of the air supply pipe P3 is inserted into the inner periphery of the pilot bit 2 in the tool body 1. Yes. Further, an exhaust plug 17 is attached to the tip of the air supply pipe P3, and the exhaust plug 17 is accommodated in the inner peripheral portion of the pilot bit 2. The air supply pipe P3 is formed in a cylindrical shape centering on an axis O having an outer diameter smaller than the inner diameter of the excavation pipe P1, and a space having an annular cross section is formed between the air supply pipe P3 and the excavation pipe P1. E is formed. Compressed air used to drive the air hammer when applying a striking force to the pilot bit 2 as described above is supplied to the inner peripheral portion of the air supply pipe P3, for example.
　排気プラグ１７は有底の多段円筒状に形成されている。具体的には、排気プラグ１７は、外径の大きい先端部と、外径の小さい後端部と、外径が先端部より小さく後端部より大きい中間部とを備え、いずれの外周面も外径が略一定の円筒面状である。小径の後端部外周には、送気パイプＰ３の先端部内周にねじ込まれる雄ネジ部が形成される。大径の先端部はパイロットビット２の内周部に僅かな間隔をあけて嵌め入れ可能な外径とされている。また、この先端部の後端面は内周側に向かうに従い後端側に向かう円錐面状に形成されている。すなわち、先端部の外周面と中間部の外周面とを接続する先端部の後端面は、円錐面状に形成されている。先端部の後端面の軸線Ｏに対する傾斜角は、同じく内周側に向かうに従い後端側に向かうパイロットビット２の上記排出路７の軸線Ｏに対する傾斜角と等しく設定されている。このような排気プラグ１７は、送気パイプＰ３の先端部に取り付けられてパイロットビット２の内周部に挿入された状態で、図１に示すように上記円錐面状の先端部後端面がパイロットビット２内周部における排出路７の開口部先端縁に位置するように配設される。言い換えると、排気プラグ１７の円錐面状の先端部後端面の外周端（先端部の後端）の位置が、軸線Ｏ方向において、パイロットビット２内周部における排出路７の開口部先端縁の位置と一致するように配設される。 The exhaust plug 17 is formed in a bottomed multistage cylindrical shape. Specifically, the exhaust plug 17 includes a front end portion having a large outer diameter, a rear end portion having a small outer diameter, and an intermediate portion having an outer diameter smaller than the front end portion and larger than the rear end portion. It has a cylindrical surface shape with a substantially constant outer diameter. On the outer periphery of the rear end portion of the small diameter, a male screw portion that is screwed into the inner periphery of the tip end portion of the air supply pipe P3 is formed. The large-diameter tip has an outer diameter that can be fitted into the inner periphery of the pilot bit 2 with a slight gap. Further, the rear end surface of the front end portion is formed in a conical surface shape toward the rear end side toward the inner peripheral side. That is, the rear end surface of the front end portion connecting the outer peripheral surface of the front end portion and the outer peripheral surface of the intermediate portion is formed in a conical shape. The inclination angle of the rear end face of the front end portion with respect to the axis O is set to be equal to the inclination angle of the pilot bit 2 toward the rear end side with respect to the axis O of the discharge passage 7 as it goes toward the inner peripheral side. Such an exhaust plug 17 is attached to the front end portion of the air supply pipe P3 and inserted into the inner peripheral portion of the pilot bit 2, and as shown in FIG. It arrange | positions so that it may be located in the opening part front-end edge of the discharge path 7 in the bit 2 inner peripheral part. In other words, the position of the outer peripheral end (rear end of the front end) of the rear end surface of the conical surface of the exhaust plug 17 is the position of the front end edge of the opening of the discharge passage 7 in the inner peripheral portion of the pilot bit 2 in the direction of the axis O. It arrange | positions so that it may correspond with a position.
　そして、有底円筒状の排気プラグ１７の内周部は円筒状の送気パイプＰ３の内周部と連通する。この排気プラグ１７の内周部から先端部後端面よりも後端側の外周面にかけては、上記空間Ｅに開口する排気孔１７Ａが、本実施形態では周方向に等間隔に複数（３つ）形成されている。すなわち、排気孔１７Ａの一端は排気プラグ１７の内周に開口し、他端は排気プラグ１７の先端部後端面と中間部外周面との接続位置に開口している。本実施形態の排気孔１７Ａは、工具本体１の外周側に向かうに従い後端側に向かうように傾斜している。なお、この排気プラグ１７の内周部から軸線Ｏに垂直な排気プラグ１７の先端面にかけても、排気孔１７Ａよりも小径の排気孔１７Ｂが形成されている。すなわち、排気孔１７Ｂの一端は排気プラグ１７の内周に開口し、他端は排気プラグ１７の先端面に開口している。また、排気孔１７Ｂは工具本体１の外周側に向かうに従い先端側に向かうように傾斜している。排気孔１７Ｂはパイロットビット２内周部の残留土砂を排出する機能を有する。 And the inner peripheral part of the bottomed cylindrical exhaust plug 17 communicates with the inner peripheral part of the cylindrical air supply pipe P3. From the inner peripheral portion of the exhaust plug 17 to the outer peripheral surface on the rear end side with respect to the rear end surface of the front end portion, a plurality (three) of exhaust holes 17A opening into the space E are equally spaced in the circumferential direction in the present embodiment. Is formed. That is, one end of the exhaust hole 17A opens to the inner periphery of the exhaust plug 17, and the other end opens to a connection position between the rear end surface of the front end portion of the exhaust plug 17 and the outer peripheral surface of the intermediate portion. The exhaust hole 17 </ b> A of the present embodiment is inclined so as to go to the rear end side as going to the outer peripheral side of the tool body 1. An exhaust hole 17B having a smaller diameter than the exhaust hole 17A is also formed from the inner peripheral portion of the exhaust plug 17 to the distal end surface of the exhaust plug 17 perpendicular to the axis O. That is, one end of the exhaust hole 17 </ b> B opens to the inner periphery of the exhaust plug 17, and the other end opens to the distal end surface of the exhaust plug 17. Further, the exhaust hole 17B is inclined so as to go to the tip side as it goes to the outer peripheral side of the tool body 1. The exhaust hole 17 </ b> B has a function of discharging residual earth and sand from the inner periphery of the pilot bit 2.
　このような掘削工具によって掘削を行う本発明の掘削工法の一実施形態では、掘削装置から掘削パイプＰ１を介してパイロットビット２に与えられた軸線Ｏ方向先端側への打撃力と推力は、パイロットビット側当接面４からケーシングトップ１３Ｂのケーシングパイプ側当接面１４を介してケーシングパイプ１３に伝達されるとともに、パイロットビット側接触面５からリングビット側接触面１０を介してリングビット３に伝達される。これにより、パイロットビット２とリングビット３の先端面に植設された掘削チップ９によって掘削孔が形成されるとともに、この掘削孔内にケーシングパイプ１３が挿入される。また、パイロットビット２に与えられた軸線Ｏ回りの回転力も、パイロットビット側接触面５からリングビット側接触面１０を介してリングビット３に伝達される。 In one embodiment of the excavation method of the present invention in which excavation is performed with such an excavation tool, the striking force and thrust to the front end side in the direction of the axis O given to the pilot bit 2 from the excavator through the excavation pipe P1 are as follows. It is transmitted from the bit side contact surface 4 to the casing pipe 13 via the casing pipe side contact surface 14 of the casing top 13B, and from the pilot bit side contact surface 5 to the ring bit 3 via the ring bit side contact surface 10. Communicated. As a result, the excavation hole is formed by the excavation tip 9 planted on the front end surfaces of the pilot bit 2 and the ring bit 3, and the casing pipe 13 is inserted into the excavation hole. The rotational force about the axis O applied to the pilot bit 2 is also transmitted from the pilot bit side contact surface 5 to the ring bit 3 via the ring bit side contact surface 10.
　また、このように掘削孔を形成するのと同時に、掘削パイプＰ１と給水パイプＰ２であるケーシングパイプ１３との間の給水路Ｆには後端側から掘削水が供給される。本実施形態における掘削水は水道水等の清水である。こうして供給された掘削水は、本実施形態では給水路Ｆの先端に開口したパイロットビット２の上記一部の溝部６Ａから掘削孔の底部に流れ込んで該底部を満たし、この一部の溝部６Ａの先端部に連通した連通溝８を流れつつパイロットビット２の回転に伴って繰り粉を巻き込みながら残りの溝部６Ｂに達し、さらにこの残りの溝部６Ｂに連通する排出路７を通ってパイロットビット２内周部の排気プラグ１７先端部後端面よりも後端側の上記空間Ｅ内に流入して排気孔１７Ａより後端側まで充填される。 Further, simultaneously with the formation of the excavation hole in this way, excavation water is supplied from the rear end side to the water supply path F between the excavation pipe P1 and the casing pipe 13 which is the water supply pipe P2. The drilling water in this embodiment is fresh water such as tap water. In this embodiment, the drilling water supplied in this way flows into the bottom portion of the drilling hole from the partial groove portion 6A of the pilot bit 2 opened at the tip of the water supply channel F and fills the bottom portion. The pilot bit 2 flows through the communication groove 8 and reaches the remaining groove portion 6B while winding the dust as the pilot bit 2 rotates, and further passes through the discharge path 7 communicating with the remaining groove portion 6B. It flows into the space E on the rear end side from the rear end surface of the front end portion of the exhaust plug 17 in the periphery, and is filled from the exhaust hole 17A to the rear end side.
　そして、このように排気孔１７Ａの後端側まで充填された繰り粉が混ざった掘削水は、送気パイプＰ３内に供給された上記圧縮空気が排気プラグ１７の内周部を通って排気孔１７Ａから噴出するのに伴って、後端側に送り出されて排出される。また、こうして掘削水が排出された上記空間Ｅの先端部は負圧となるので、残りの溝部６Ｂから排出路７内に残った掘削水は繰り粉ごと空間Ｅの先端部に吸引される。このように、掘削水と繰り粉とは、排気孔１７Ａからの圧縮空気の噴出によって連続的に排出される。 Then, the drilling water mixed with the dust filled up to the rear end side of the exhaust hole 17A in this way passes through the inner peripheral portion of the exhaust plug 17 and the exhaust air is supplied to the compressed air supplied into the air supply pipe P3. As it ejects from 17A, it is sent to the rear end side and discharged. Further, since the tip of the space E from which the drilling water has been discharged becomes negative pressure, the drilling water remaining in the discharge path 7 from the remaining groove 6B is sucked together with the flour by the tip of the space E. In this way, the drilling water and the flour are continuously discharged by the ejection of compressed air from the exhaust hole 17A.
　このように、上記構成の掘削工具および掘削工法によれば、真空ポンプなどを必要とすることなく、上述のような工具本体１のパイロットビット２およびリングビット３に打撃力を与えるための圧縮空気などを利用して、繰り粉が混ざった掘削水を排出することができる。排出される掘削水が通過するのは、掘削パイプＰ１と送気パイプＰ３との間の空間Ｅであるので、繰り粉が混ざっていても排出に支障を来すことはない。このため、長期に亙って安定して効率的に低コストの掘削および繰り粉の排出を図ることができる。 Thus, according to the excavation tool and excavation method having the above-described configuration, the compressed air for applying the striking force to the pilot bit 2 and the ring bit 3 of the tool body 1 as described above without requiring a vacuum pump or the like. It is possible to discharge drilling water mixed with flour. The excavated water to be discharged passes through the space E between the excavated pipe P1 and the air supply pipe P3. Therefore, even if dusting is mixed, the discharge is not hindered. For this reason, it is possible to achieve stable and efficient low-cost excavation and dust discharge over a long period of time.
　また、打撃力を与えるための圧縮空気は、上記空間Ｅに後端側に向けて排気されて繰り粉が混ざった掘削水の排出に用いられるので、掘削孔の周囲に漏れ出ることはなく、しかも掘削孔の底部には掘削水が充填されるため、周囲の岩盤が強度低下によって崩落するようなこともない。さらに、掘削水も掘削パイプＰ１と給水パイプＰ２であるケーシングパイプ１３との間の給水路Ｆを通って供給されるので、掘削水として泥水などより比重の低い上述のような清水を用いることができ、排気孔１７Ａから噴出する圧縮空気に必要以上の圧力が要求されることもない。 Moreover, since the compressed air for giving a striking force is used for discharging drilling water that is exhausted toward the rear end side in the space E and mixed with dust, it does not leak around the drill hole, Moreover, since the bottom of the excavation hole is filled with excavation water, the surrounding rock mass does not collapse due to strength reduction. Furthermore, since the drilling water is also supplied through the water supply path F between the drill pipe P1 and the casing pipe 13 which is the water supply pipe P2, the above-described fresh water having a lower specific gravity than muddy water or the like can be used as the drilling water. The compressed air ejected from the exhaust hole 17A is not required to have a pressure higher than necessary.
　また、本実施形態では、排気孔１７Ａが工具本体１の外周側に向かうに従い後端側に向かうように傾斜しているので、排気孔１７Ａから排気される圧縮空気によって空間Ｅ内の繰り粉と掘削水を一層確実に後端側に排出することができる。さらに、本実施形態では、このように掘削パイプＰ１が給水パイプＰ２としてのケーシングパイプ１３内に挿通されていて、給水路Ｆがこれら掘削パイプＰ１とケーシングパイプ１３（給水パイプＰ２）との間に形成されており、掘削孔を形成しつつケーシングパイプ１３を掘削孔に建て込む基礎杭打ち工法に本実施形態を適用することができる。言い換えると、掘削水が給水路Ｆを介して工具本体１の先端側にのみ供給される。このため、掘削孔自体の崩落を防ぎつつ、掘削水を確実に工具本体１先端部の掘削孔底部に供給して繰り粉を排出することが可能となる。 Further, in the present embodiment, the exhaust hole 17A is inclined so as to go to the rear end side as it goes to the outer peripheral side of the tool body 1, so that the dust in the space E is compressed by the compressed air exhausted from the exhaust hole 17A. Drilling water can be more reliably discharged to the rear end side. Further, in the present embodiment, the excavation pipe P1 is inserted into the casing pipe 13 as the water supply pipe P2, and the water supply path F is between the excavation pipe P1 and the casing pipe 13 (water supply pipe P2). The present embodiment can be applied to the foundation pile driving method in which the casing pipe 13 is built in the excavation hole while forming the excavation hole. In other words, the drilling water is supplied only to the tip side of the tool body 1 through the water supply channel F. For this reason, it becomes possible to supply the drilling water to the bottom of the drilling hole at the tip of the tool body 1 and discharge the dust while preventing the drilling hole itself from collapsing.
　また、このようにケーシングパイプ１３内に掘削パイプＰ１を挿通してその間の給水路Ｆに掘削水を供給するのに併せて、本実施形態では、この掘削パイプＰ１の先端部に取り付けられる工具本体１のパイロットビット２の先端部外周に、その先端面から後端側に延びる複数条の溝部６を周方向に間隔をあけて形成し、このうち一部の溝部６Ａは上記給水路Ｆに連通させるとともに、残りの溝部６Ｂは排出路７を介して掘削水が排出される上記空間Ｅに連通させている。そして、これら一部の溝部６Ａと残りの溝部６Ｂの先端部は、パイロットビット２の先端面に形成された連通溝８によって連通しているので、パイロットビット２やリングビット３の先端面に植設された掘削チップ９によって生成された繰り粉を満遍なく連通溝８に取り込んで掘削水とともに確実に排出することができる。 In addition, in this embodiment, in addition to supplying the drilling pipe P1 into the casing pipe 13 and supplying the drilling water to the water supply path F therebetween, in this embodiment, the tool body attached to the tip of the drilling pipe P1. A plurality of groove portions 6 extending from the front end surface to the rear end side are formed on the outer periphery of the front end portion of one pilot bit 2 at intervals in the circumferential direction, and some of the groove portions 6A communicate with the water supply path F. At the same time, the remaining groove 6 </ b> B communicates with the space E through which the drilling water is discharged via the discharge path 7. The tip portions of some of the groove portions 6A and the remaining groove portions 6B communicate with each other through the communication groove 8 formed on the tip surface of the pilot bit 2, so that the tip portions of the pilot bit 2 and the ring bit 3 are planted. The flour produced by the provided excavation tip 9 can be uniformly taken into the communication groove 8 and reliably discharged together with the excavation water.
　さらに、本実施形態では、パイロットビット２とリングビット３とが、円錐面状のパイロットビット側接触面５とリングビット側接触面１０との密着によって軸線Ｏ回りに一体に回転するように構成されている。このため、これらパイロットビット２とリングビット３との間では、上記一部の溝部６Ａ以外の箇所から掘削水が掘削孔に供給されたり、上記残りの溝部６Ｂ以外の箇所から繰り粉を含んだ掘削水が排出されたりするのを防ぐことができる。その結果、上述のように連通溝８によって取り込んだ繰り粉を含む掘削水を一層確実に排出することが可能となる。 Further, in this embodiment, the pilot bit 2 and the ring bit 3 are configured to rotate integrally around the axis O by the close contact between the conical pilot bit side contact surface 5 and the ring bit side contact surface 10. ing. For this reason, between the pilot bit 2 and the ring bit 3, the drilling water is supplied to the drilling hole from a part other than the part of the groove part 6A, or the flour is contained from a part other than the remaining groove part 6B. It is possible to prevent the drilling water from being discharged. As a result, it becomes possible to more reliably discharge the drilling water containing the flour that has been taken in by the communication groove 8 as described above.
　なお、上記第１の実施形態では、上述のようにパイロットビット２の先端部外周に形成された複数の溝部６のうち、給水路Ｆに連通する一部の溝部６Ａの先端部と排出路７を介して空間Ｅに連通する残りの溝部６Ｂの先端部とを連通溝８によって連通しているが、図５ないし図８に示す第２の実施形態のように、工具本体１のパイロットビット２先端部外周の溝部６の内周側に孔部１８を排出路７として形成し、この孔部１８と溝部６の先端部を連通溝１９によって連通するようにしてもよい。なお、これら図５ないし図８において図１ないし図４に示した第１の実施形態と共通する部分には同一の符号を配して説明を省略する。 In the first embodiment, among the plurality of grooves 6 formed on the outer periphery of the front end of the pilot bit 2 as described above, the front ends of some of the grooves 6A communicating with the water supply path F and the discharge path 7 are provided. The tip of the remaining groove 6B that communicates with the space E via the communication groove 8 is communicated by the communication groove 8, but the pilot bit 2 of the tool body 1 as in the second embodiment shown in FIGS. A hole 18 may be formed as the discharge path 7 on the inner peripheral side of the groove 6 on the outer periphery of the tip, and the hole 18 and the tip of the groove 6 may be communicated by the communication groove 19. 5 to 8, the same reference numerals are assigned to the same parts as those of the first embodiment shown in FIGS. 1 to 4, and description thereof is omitted.
　すなわち、この第２の実施形態では、パイロットビット２の先端部外周に形成された複数条（本実施形態でも３条）の溝部６は、すべて第１の実施形態の一部の溝部６Ａと同様にパイロットビット２の先端部後端面に開口して、掘削パイプＰ１とケーシングパイプ１３（給水パイプＰ２）との間の給水路Ｆと連通している。一方、パイロットビット２の先端部には、その先端面からパイロットビット２の内周部に貫通する断面円形の上記孔部１８が各溝部６の内周側で軸線Ｏから離れた位置に形成されている。孔部１８は軸線Ｏに平行に延び、先端側端部がパイロットビット２の先端面に開口し、後端側端部がパイロットビット２の内周面に開口する。 That is, in this second embodiment, the plurality of grooves 6 (three also in this embodiment) formed on the outer periphery of the tip end portion of the pilot bit 2 are all the same as some of the grooves 6A of the first embodiment. The pilot bit 2 is opened to the rear end surface of the pilot bit 2 and communicates with the water supply path F between the excavation pipe P1 and the casing pipe 13 (water supply pipe P2). On the other hand, the hole 18 having a circular cross section penetrating from the tip surface of the pilot bit 2 to the inner peripheral portion of the pilot bit 2 is formed at a position away from the axis O on the inner peripheral side of each groove portion 6. ing. The hole 18 extends in parallel with the axis O, the front end side end opens to the front end surface of the pilot bit 2, and the rear end side end opens to the inner peripheral surface of the pilot bit 2.
　そして、これらの孔部１８の先端部と溝部６の先端部とが、軸線Ｏに垂直な平面上を該軸線Ｏに対する径方向に放射状に延びる連通溝１９を介して連通している。また、パイロットビット２の内周部に収容された排気プラグ１７の大径の先端部には、この先端部の外周を軸線Ｏ方向に貫通する切欠１７Ｃが、周方向において複数（３つ）の排気孔１７Ａの間にそれぞれ形成されている。 Further, the tip end portions of these hole portions 18 and the tip end portions of the groove portions 6 communicate with each other via a communication groove 19 extending radially in a radial direction with respect to the axis O on a plane perpendicular to the axis O. Further, the large-diameter distal end portion of the exhaust plug 17 accommodated in the inner peripheral portion of the pilot bit 2 has a plurality of (three) notches 17C penetrating the outer periphery of the distal end portion in the direction of the axis O in the circumferential direction. Each is formed between the exhaust holes 17A.
　このような第２の実施形態においても、給水路Ｆから供給された切削水は各溝部６を通って工具本体１のパイロットビット２先端側に流れ、次いで連通溝１９を流れるうちに繰り粉を巻き込んで孔部１８の先端に達し、この孔部１８からパイロットビット２の内周部に流れ込んで切欠１７Ｃから排気プラグ１７の排気孔１７Ａより後端側まで充填される。そして、この排気孔１７Ａから圧縮空気が排気されることにより、繰り粉が混ざった切削水は後端側に押し出されて排出され、また孔部１８からは新たな繰り粉が混ざった掘削水が吸引される。 Also in the second embodiment, the cutting water supplied from the water supply path F flows to the tip end side of the pilot bit 2 of the tool body 1 through each groove portion 6, and then flours while flowing through the communication groove 19. It winds up and reaches the tip of the hole 18, flows from the hole 18 into the inner peripheral portion of the pilot bit 2, and is filled from the notch 17 </ b> C to the rear end side from the exhaust hole 17 </ b> A of the exhaust plug 17. Then, the compressed air is exhausted from the exhaust hole 17A, so that the cutting water mixed with the dust is pushed and discharged to the rear end side, and the drilling water mixed with the new dust is discharged from the hole 18. Sucked.
　このように、上記第２の実施形態の掘削工具およびこれを用いた掘削工法でも、第１の実施形態と同様に真空ポンプなどを必要とすることなく、また圧縮空気に高い圧力を要することもなく、周囲の岩盤の崩落を防ぎながら安定的かつ効率的で低コストの掘削を行うことが可能となる。また、この第２の実施形態では、第１の実施形態とパイロットビット２の先端部に形成される溝部６の数が同じでも、より多くの切削水を工具本体１の先端側に供給できるとともに、繰り粉を巻き込んだ切削水が連通溝１９を流れる距離を短くできるので、高速で掘削を行う場合にも好適である。 As described above, the excavation tool of the second embodiment and the excavation method using the excavation tool do not require a vacuum pump or the like as in the first embodiment, and may require high pressure to the compressed air. In addition, it is possible to perform stable, efficient and low-cost excavation while preventing the surrounding rock mass from collapsing. In the second embodiment, more cutting water can be supplied to the distal end side of the tool body 1 even if the number of grooves 6 formed in the distal end portion of the pilot bit 2 is the same as that in the first embodiment. Moreover, since the distance in which the cutting water entrained with the flour flows through the communication groove 19 can be shortened, it is also suitable for excavation at high speed.
　本発明の掘削工具および掘削工法によれば、真空ポンプを用いることなく、繰り粉が混ざった水を効率的に排出することができるので、本発明は基礎杭打ち工法に好適である。 According to the excavation tool and excavation method of the present invention, water mixed with flour can be efficiently discharged without using a vacuum pump, so the present invention is suitable for the foundation pile driving method.
　１　工具本体
　２　パイロットビット
　３　リングビット
　４　パイロットビット側当接面
　５　パイロットビット側接触面
　６　溝部
　６Ａ　一部の溝部
　６Ｂ　残りの溝部
　７　排出路
　８、１９　連通溝
　９　掘削チップ
　１０　リングビット側接触面
　１３　ケーシングパイプ
　１４　ケーシングパイプ側当接面
　１７　排気プラグ
　１７Ａ　排気孔
　１７Ｃ　切欠
　１８　孔部（排出路）
　Ｐ１　掘削パイプ
　Ｐ２　給水パイプ
　Ｐ３　送気パイプ
　Ｏ　工具本体１の軸線
　Ｆ　給水路
　Ｅ　掘削パイプＰ１と送気パイプＰ３との間の空間 DESCRIPTION OF SYMBOLS 1 Tool main body 2 Pilot bit 3 Ring bit 4 Pilot bit side contact surface 5 Pilot bit side contact surface 6 Groove part 6A Some groove parts 6B Remaining groove part 7 Discharge path 8, 19 Communication groove 9 Excavation tip 10 Ring bit side contact surface 13 Casing pipe 14 Casing pipe side contact surface 17 Exhaust plug 17A Exhaust hole 17C Notch 18 Hole (discharge path)
P1 Excavation pipe P2 Water supply pipe P3 Air supply pipe O Axis line of tool body 1 F Water supply path E Space between excavation pipe P1 and air supply pipe P3

Claims (6)

  1. 　先端部に工具本体が配設される掘削パイプの内周に圧縮空気を供給する送気パイプが挿通されるとともに、上記掘削パイプの外周には、上記工具本体の先端部に掘削水を供給する給水路が設けられており、
    　上記工具本体の先端部には、掘削時に生成された繰り粉を上記給水路から供給された上記掘削水とともに上記掘削パイプと上記送気パイプとの間の空間に排出する排出路が形成され、
    　上記送気パイプの先端部には、上記空間に開口する排気孔が形成されていることを特徴とする掘削工具。     An air supply pipe that supplies compressed air is inserted into the inner periphery of the drilling pipe in which the tool body is disposed at the tip, and drilling water is supplied to the tip of the tool body at the outer periphery of the drilling pipe. There is a water supply channel,
    The tip of the tool body is formed with a discharge path that discharges the flour generated during excavation into the space between the drilling pipe and the air supply pipe together with the drilling water supplied from the water supply path,
    An excavation tool characterized in that an exhaust hole opening in the space is formed at a tip of the air supply pipe.
  2. 　上記排気孔は、上記工具本体の外周側に向かうに従い後端側に向かうように傾斜して上記空間に開口していることを特徴とする請求項１に記載の掘削工具。 2. The excavation tool according to claim 1, wherein the exhaust hole is inclined to open toward the rear end side toward the outer peripheral side of the tool body and opens in the space.
  3. 　上記掘削パイプは給水パイプの内周に挿通されており、上記給水路は上記給水パイプと上記掘削パイプとの間に形成されていることを特徴とする請求項１または請求項２に記載の掘削工具。 The excavation pipe according to claim 1 or 2, wherein the excavation pipe is inserted into an inner periphery of the water supply pipe, and the water supply path is formed between the water supply pipe and the excavation pipe. tool.
  4. 　上記工具本体の先端部外周には、該工具本体の先端から後端側に延びる複数条の溝部が形成されていて、
    　これら複数条の溝部のうち、一部の溝部は上記給水路に連通するとともに、残りの溝部は上記排出路に連通しており、
    　上記一部の溝部の先端部と上記残りの溝部の先端部とが、上記工具本体の先端面に形成された連通溝を介して連通していることを特徴とする請求項１から請求項３のうちいずれか一項に記載の掘削工具。     On the outer periphery of the tip end of the tool body, a plurality of grooves extending from the tip end of the tool body to the rear end side are formed,
    Among these multiple grooves, some of the grooves communicate with the water supply channel, and the remaining grooves communicate with the discharge channel.
    The tip part of the said some groove part and the tip part of the said remaining groove part are connected via the communication groove formed in the front end surface of the said tool main body, The Claims 1-3 characterized by the above-mentioned. The excavation tool as described in any one of these.
  5. 　上記工具本体の先端部外周には、該工具本体の先端から後端側に延びて上記給水路に連通する溝部が形成されるとともに、
    　この溝部よりも内周側の上記工具本体内には、該工具本体の先端から後端側に延びる孔部が上記排出路として形成されており、
    　上記溝部の先端部と上記孔部の先端部とが、上記工具本体の先端面に形成された連通溝を介して連通していることを特徴とする請求項１から請求項３のうちいずれか一項に記載の掘削工具。     On the outer periphery of the tip of the tool body, a groove is formed that extends from the tip of the tool body to the rear end side and communicates with the water supply channel.
    A hole extending from the front end of the tool main body to the rear end side is formed as the discharge path in the tool main body on the inner peripheral side of the groove,
    The tip part of the said groove part and the tip part of the said hole part are connected via the communication groove formed in the front end surface of the said tool main body, The any one of Claims 1-3 characterized by the above-mentioned. The excavation tool according to one item.
  6. 　請求項１から請求項５のうちいずれか一項に記載の掘削工具を用いて、
    　上記工具本体により掘削孔を形成しつつ、上記給水路を介して上記工具本体の先端部に掘削水を供給し、
    　掘削時に生成された繰り粉を上記掘削水とともに上記排出路を通して上記掘削パイプと上記送気パイプとの間の空間に排出し、
    　この空間に排出された上記繰り粉と掘削水とを、上記排気孔から排気される圧縮空気によって後端側に排出することを特徴とする掘削工法。     Using the excavation tool according to any one of claims 1 to 5,
    While forming a drilling hole with the tool body, supply drilling water to the tip of the tool body through the water supply channel,
    The dust produced during excavation is discharged into the space between the excavation pipe and the air supply pipe through the discharge passage together with the excavation water,
    The excavation method characterized in that the dust and the drilling water discharged into this space are discharged to the rear end side by compressed air exhausted from the exhaust hole.
PCT/JP2016/086558 2016-01-20 2016-12-08 Excavation tool and excavation method WO2017126247A1 (en)

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