WO2019049501A1 - ピストンユニット及び流体圧シリンダ - Google Patents
ピストンユニット及び流体圧シリンダ Download PDFInfo
- Publication number
- WO2019049501A1 WO2019049501A1 PCT/JP2018/025733 JP2018025733W WO2019049501A1 WO 2019049501 A1 WO2019049501 A1 WO 2019049501A1 JP 2018025733 W JP2018025733 W JP 2018025733W WO 2019049501 A1 WO2019049501 A1 WO 2019049501A1
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- WO
- WIPO (PCT)
- Prior art keywords
- piston
- piston unit
- yoke
- magnets
- outer peripheral
- Prior art date
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Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B15/00—Fluid-actuated devices for displacing a member from one position to another; Gearing associated therewith
- F15B15/08—Characterised by the construction of the motor unit
- F15B15/14—Characterised by the construction of the motor unit of the straight-cylinder type
- F15B15/1423—Component parts; Constructional details
- F15B15/1447—Pistons; Piston to piston rod assemblies
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B15/00—Fluid-actuated devices for displacing a member from one position to another; Gearing associated therewith
- F15B15/08—Characterised by the construction of the motor unit
- F15B15/14—Characterised by the construction of the motor unit of the straight-cylinder type
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B15/00—Fluid-actuated devices for displacing a member from one position to another; Gearing associated therewith
- F15B15/08—Characterised by the construction of the motor unit
- F15B15/14—Characterised by the construction of the motor unit of the straight-cylinder type
- F15B15/1423—Component parts; Constructional details
- F15B15/1447—Pistons; Piston to piston rod assemblies
- F15B15/1452—Piston sealings
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B15/00—Fluid-actuated devices for displacing a member from one position to another; Gearing associated therewith
- F15B15/20—Other details, e.g. assembly with regulating devices
- F15B15/28—Means for indicating the position, e.g. end of stroke
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B15/00—Fluid-actuated devices for displacing a member from one position to another; Gearing associated therewith
- F15B15/20—Other details, e.g. assembly with regulating devices
- F15B15/28—Means for indicating the position, e.g. end of stroke
- F15B15/2807—Position switches, i.e. means for sensing of discrete positions only, e.g. limit switches
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B15/00—Fluid-actuated devices for displacing a member from one position to another; Gearing associated therewith
- F15B15/20—Other details, e.g. assembly with regulating devices
- F15B15/28—Means for indicating the position, e.g. end of stroke
- F15B15/2815—Position sensing, i.e. means for continuous measurement of position, e.g. LVDT
- F15B15/2861—Position sensing, i.e. means for continuous measurement of position, e.g. LVDT using magnetic means
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B15/00—Fluid-actuated devices for displacing a member from one position to another; Gearing associated therewith
- F15B15/20—Other details, e.g. assembly with regulating devices
- F15B15/28—Means for indicating the position, e.g. end of stroke
- F15B15/2892—Means for indicating the position, e.g. end of stroke characterised by the attachment means
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16J—PISTONS; CYLINDERS; SEALINGS
- F16J1/00—Pistons; Trunk pistons; Plungers
- F16J1/005—Pistons; Trunk pistons; Plungers obtained by assembling several pieces
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B15/00—Fluid-actuated devices for displacing a member from one position to another; Gearing associated therewith
- F15B15/20—Other details, e.g. assembly with regulating devices
- F15B15/22—Other details, e.g. assembly with regulating devices for accelerating or decelerating the stroke
- F15B15/223—Other details, e.g. assembly with regulating devices for accelerating or decelerating the stroke having a piston with a piston extension or piston recess which completely seals the main fluid outlet as the piston approaches its end position
Definitions
- the present invention relates to a piston unit and a hydraulic cylinder in which a magnet is disposed on the outer peripheral portion.
- a fluid pressure cylinder having a piston that is displaced along with the supply of pressure fluid is known as a transfer means (actuator) such as a work.
- actuator such as a work.
- a fluid pressure cylinder has a cylinder tube, a piston axially movably disposed in the cylinder tube, and a piston rod connected to the piston.
- JP 2008-133920A discloses a fluid pressure cylinder in which a ring magnet is mounted on the outer periphery of the piston and a magnetic sensor is disposed outside the cylinder tube in order to detect the position of the piston. ing.
- the magnetic sensor is disposed only at a part of the circumferential direction of the cylinder tube, whereas the magnet is ring-shaped (entirely circumferential). For this reason, the magnet has more volume than necessary for detecting the position of the piston.
- a magnet non-ring magnet
- the present invention has been made in view of such problems, and an object thereof is to provide a piston unit and a hydraulic cylinder capable of forming a magnetic field over the entire circumference without using a ring magnet. .
- the present invention is a piston unit capable of reciprocating along a slide hole formed in a cylinder tube, the piston body, and a packing mounted on the outer peripheral portion of the piston body.
- a holding member mounted on an outer peripheral portion of the piston main body and having a plurality of magnet holding portions arranged in a circumferential direction; and a plurality of magnets held at a circumferential interval by the plurality of magnet holding portions And a ring-shaped first yoke disposed on one side of the plurality of magnets in the axial direction, and a ring-shaped second yoke disposed on the other side of the plurality of magnets in the axial direction.
- the plurality of magnets are arranged at intervals in the circumferential direction by the holding member, and the ring-shaped first and second yokes are provided on both sides of the plurality of magnets. It is arranged. For this reason, a magnetic field can be formed over the entire circumference of the piston unit without using a ring magnet.
- a common magnet can be adopted to fluid pressure cylinders having different cylinder diameters (piston diameters). That is, it is not necessary to use magnets of different sizes for each cylinder diameter.
- Each of the plurality of magnets is shaped to have a short axis and a long axis perpendicular to the axis of the piston body, and is held by the holding member such that the long axis is along the circumferential direction of the piston body Is preferred.
- the number of the plurality of magnets is preferably four, and the plurality of magnets are preferably arranged at equal intervals in the circumferential direction.
- the piston main body has a plurality of piston members, and the plurality of piston members form a ring-shaped receiving groove for receiving the plurality of magnet holding portions, the first yoke, and the second yoke. preferable.
- the ring-shaped first yoke and the second yoke can be easily assembled on both sides of the plurality of magnets.
- a ring-shaped packing attachment groove to which the packing is attached is formed on an outer peripheral portion of the piston body, one side wall of the packing attachment groove is formed by the piston body, and the other side wall of the packing attachment groove is Preferably, it is formed by the outer peripheral portion of the first yoke.
- the ring-shaped packing can be easily assembled, and the axial dimension of the piston main body can be shortened.
- the second yoke preferably includes an adjacent portion adjacent to the plurality of magnets, and a ring-shaped axial portion protruding from an outer peripheral portion of the adjacent portion in the axial direction away from the first yoke.
- the area of the outer periphery of the second yoke can be increased, and the magnetic flux density of the magnetic field formed outside the piston unit can be effectively increased.
- the holding member be supported by an outer peripheral surface of the axial direction portion of the second yoke.
- the holding member can be favorably supported using the axial direction portion.
- the outer peripheral surface of the first yoke and the outer peripheral surface of the second yoke be positioned more outward than the outer ends of the plurality of magnets.
- the magnetic flux density of the magnetic field formed outside the piston unit can be effectively increased.
- the magnet holding portion has a cutout portion opened at an outer peripheral surface of the holding member.
- the magnet can be disposed at a position close to the inner circumferential surface of the cylinder tube.
- the distance between the magnetic sensor attached to the outside of the cylinder tube and the magnet disposed on the inside of the cylinder tube can be reduced, so that the magnetic force required for the magnet can be reduced. Therefore, the axial dimension of the piston unit can be shortened by reducing the axial thickness of the magnet.
- the holding member is preferably a wear ring configured to prevent the piston body from contacting the cylinder tube.
- the holding member serves both as the member for holding the magnet and the wear ring, so that the structure can be simplified.
- a cylinder tube having a slide hole inside, a piston unit arranged to be reciprocally movable along the slide hole, and a piston rod axially protruding from the piston unit.
- the piston unit is any one of the above-mentioned piston units.
- a magnetic field can be formed over the entire circumference of the piston unit without using a ring magnet.
- FIG. 1 is a perspective view of a fluid pressure cylinder according to a first embodiment of the present invention.
- FIG. 2 is a cross-sectional view of the fluid pressure cylinder shown in FIG.
- FIG. 3 is an exploded perspective view of the fluid pressure cylinder shown in FIG.
- FIG. 4 is a perspective view of a cylinder tube according to another configuration.
- FIG. 5 is a partial cross-sectional side view of a fluid pressure cylinder according to a second embodiment of the present invention.
- the fluid pressure cylinder 10 includes a hollow cylindrical cylinder tube 12 having a circular slide hole 13 (cylinder chamber) therein, and a rod disposed at one end of the cylinder tube 12 A cover 14 and a head cover 16 disposed at the other end of the cylinder tube 12 are provided. Also, as shown in FIGS. 2 and 3, the fluid pressure cylinder 10 is provided with a piston unit 18 disposed movably in the axial direction (X direction) in the cylinder tube 12, and a piston rod connected to the piston unit 18. And 20.
- the fluid pressure cylinder 10 is used, for example, as an actuator for transporting a work.
- the cylinder tube 12 is made of, for example, a metal material such as an aluminum alloy, and is formed of a cylindrical body extending along the axial direction. In the first embodiment, the cylinder tube 12 is formed in a hollow cylindrical shape.
- the rod cover 14 is provided to close one end (end on the arrow X1 direction) of the cylinder tube 12 and, for example, a metal material similar to that of the cylinder tube 12 It is a member constituted by.
- the rod cover 14 is provided with a first port 15 a.
- an annular protrusion 14 b provided on the rod cover 14 is inserted into one end of the cylinder tube 12.
- a circular ring-shaped packing 23 is disposed between the rod cover 14 and the cylinder tube 12.
- a circular ring-shaped bush 25 and packing 27 are disposed on the inner peripheral portion of the rod cover 14.
- a circular ring-shaped first cushion packing 68 a is disposed on the inner peripheral portion of the rod cover 14.
- the head cover 16 is, for example, a member made of the same metal material as the cylinder tube 12 and is provided so as to close the other end (the end on the arrow X2 direction side) of the cylinder tube 12.
- the other end of the cylinder tube 12 is airtightly closed by the head cover 16.
- the head cover 16 is provided with a second port 15 b.
- An annular protrusion 16 b provided on the head cover 16 is inserted into the other end of the cylinder tube 12.
- a circular ring shaped packing 31 is disposed between the head cover 16 and the cylinder tube 12.
- a circular ring-shaped second cushion packing 68 b is disposed on the inner peripheral portion of the head cover 16.
- the cylinder tube 12, the rod cover 14 and the head cover 16 are axially fastened by a plurality of connecting rods 32 and nuts 34.
- a plurality of sets of connecting rods 32 and nuts 34 are circumferentially spaced. For this reason, the cylinder tube 12 is fixed in a state of being held between the head cover 16 and the rod cover 14.
- the piston unit 18 is axially slidably accommodated in the cylinder tube 12 (sliding hole 13), and the inside of the sliding hole 13 is the first port 15a side. It divides into the pressure chamber 13a and the 2nd pressure chamber 13b by the side of the 2nd port 15b.
- the piston unit 18 is connected to the proximal end 20 a of the piston rod 20.
- the piston unit 18 is mounted on a circular piston main body 40 projecting radially outward from the piston rod 20, a circular ring-like packing 42 mounted on the outer peripheral part of the piston main body 40, and an outer peripheral part of the piston main body 40
- a holding member 44 having a plurality of magnet holding portions 58, a plurality of magnets 46 disposed on the outer peripheral portion of the piston main body 40, and a first yoke 47 made of a magnetic material disposed adjacent to the plurality of magnets 46.
- a second yoke 48 is provided on a circular piston main body 40 projecting radially outward from the piston rod 20, a circular ring-like packing 42 mounted on the outer peripheral part of the piston main body 40, and an outer peripheral part of the piston main body 40
- a holding member 44 having a plurality of magnet holding portions 58, a plurality of magnets 46 disposed on the outer peripheral portion of the piston main body 40, and a first yoke 47 made of a magnetic material disposed adjacent to the plurality of
- the piston body 40 has an axially extending through hole 40 h.
- the base end portion 20a (small diameter portion) of the piston rod 20 is inserted into the through hole 40h of the piston main body 40 and fixed (connected) to the piston main body 40 by caulking.
- the fixing structure between the piston rod 20 and the piston main body 40 is not limited to caulking, and may be a screwing-in structure.
- a packing attachment groove 50, a ring-shaped accommodation groove 52, and a yoke support surface 54 are provided at different positions in the axial direction on the outer peripheral portion of the piston main body 40.
- the ring-shaped accommodation groove 52 is provided between the packing attachment groove 50 and the yoke support surface 54.
- Each of the packing attachment groove 50 and the ring-shaped receiving groove 52 is formed in a circular ring shape extending along the entire circumferential direction.
- the ring-shaped accommodation groove 52 accommodates the plurality of magnet holding portions 58, the first yoke 47 and the second yoke 48.
- the groove depth of the ring-shaped accommodation groove 52 is deeper than the groove depth of the packing attachment groove 50.
- the bottom surface of the ring-shaped receiving groove 52 is located radially inward of the bottom surface of the packing attachment groove 50.
- the piston body 40 has a plurality of piston members, and the ring-shaped receiving groove 52 is formed by the plurality of piston members.
- the piston main body 40 has a first piston member 40a and a second piston member 40b which are disposed adjacent to each other in the axial direction, and the first piston member 40a and the second piston member 40b
- the ring-shaped accommodation groove 52 is formed by this. That is, the piston main body 40 has a structure divided into the first piston member 40a and the second piston member 40b in the axial direction.
- the first piston member 40a has a first large diameter portion 40a1 and a first small diameter portion 40a2.
- the outer peripheral portion of the first large diameter portion 40a1 constitutes one side wall of the packing attachment groove 50.
- the outer peripheral surface of the first small diameter portion 40a2 constitutes the bottom of the packing attachment groove 50.
- the outer peripheral portion of the first small diameter portion 40a2 constitutes one side wall of the ring-shaped accommodation groove 52.
- the outer peripheral portion of the first yoke 47 constitutes the other side wall of the packing attachment groove 50.
- the second piston member 40b has a second small diameter portion 40b1 and a second large diameter portion 40b2.
- the outer peripheral surface of the second small diameter portion 40b1 constitutes the bottom surface of the ring-shaped accommodation groove 52.
- the outer peripheral portion of the second large diameter portion 40 b 2 constitutes the other side wall of the ring-shaped accommodation groove 52.
- piston main body 40 As a constituent material of piston main body 40 (the 1st piston member 40a and the 2nd piston member 40b), metal materials, such as carbon steel, stainless steel, aluminum alloy, hard resin etc. are mentioned, for example.
- the piston main body 40 is preferably made of a nonmagnetic material so that the magnetic lines of force generated by the magnetic structure 49 described later can be well guided to the outside of the piston unit 18.
- the first piston member 40a and the second piston member 40b may be made of materials different from each other.
- the packing 42 is a ring-shaped seal member (for example, an O-ring) made of an elastic material such as a rubber material or an elastomer material.
- the packing 42 is mounted in the packing mounting groove 50.
- the packing 42 is slidably in contact with the inner circumferential surface of the cylinder tube 12. Specifically, the packing 42 is in tight or liquid-tight contact with the inner circumferential surface of the cylinder tube 12 and the outer circumferential surface of the piston main body 40 over the entire circumference.
- the holding member 44 has a ring-shaped circumferential direction portion 57 extending in the circumferential direction along the outer circumferential portion of the piston main body 40 and a plurality of magnet holding portions 58 projecting from the circumferential direction portion 57.
- the circumferential portion 57 is supported by the outer circumferential surface of the second yoke 48.
- a plurality of magnet holding portions 58 are provided at intervals in the circumferential direction. In the present embodiment, four magnet holding portions 58 are provided at equal intervals in the circumferential direction.
- the magnet holding portion 58 is inserted into the ring-shaped receiving groove 52 of the piston main body 40.
- the magnet 46 is held (mounted) by the magnet holding portion 58.
- the magnet holding portion 58 has a notch 58 c opened at the outer peripheral surface of the holding member 44.
- the magnet holding portion 58 protrudes radially inward from the inner circumferential surface of the circumferential portion 57. More specifically, the magnet holding portion 58 has a pair of holding arms 58 a protruding radially inward from the circumferential portion 57. The pair of holding arms 58a are spaced apart from each other in the circumferential direction and opposed to each other, and the magnet 46 is held between the pair of holding arms 58a. At the tip (free end) of each holding arm 58a, an engagement claw 58b that engages with the magnet 46 is provided.
- the magnet holding portion 58 may have a U-shaped frame-shaped structure by connecting the tips of the pair of holding arms 58a.
- the holding member 44 is a wear ring 44A configured to prevent the piston body 40 from coming into contact with the cylinder tube 12, and is attached to the second yoke 48.
- the outer peripheral surface of the piston main body 40 contacts the inner peripheral surface of the slide hole 13 when a large lateral load in the direction perpendicular to the axial direction acts on the piston unit 18 during operation of the fluid pressure cylinder 10. To prevent that.
- the outer diameter of the wear ring 44A is larger than the outer diameter of the piston main body 40.
- the wear ring 44A is made of a low friction material.
- the coefficient of friction between the wear ring 44A and the inner peripheral surface of the slide hole 13 is smaller than the coefficient of friction between the packing 42 and the inner peripheral surface of the slide hole 13.
- a synthetic resin material having both low friction and abrasion resistance such as tetrafluoroethylene (PTFE), a metal material (for example, bearing steel) and the like can be mentioned.
- the plurality of magnets 46 are attached to the plurality of magnet holding portions 58.
- four magnets 46 are arranged at equal intervals in the circumferential direction.
- the number of magnets 46 may be three or less or five or more.
- the magnet 46 has a short axis and a long axis perpendicular to the axis of the piston body 40 and is held by the holding member 44 so that the long axis is along the circumferential direction of the piston body 40.
- the magnet 46 has a rectangular parallelepiped shape, and the long side direction of the magnet 46 is disposed along the circumferential direction of the piston main body 40. That is, the short side direction of the magnet 46 is along the radial direction of the piston main body 40.
- the magnet 46 has a thickness in the direction of arrow X (dimension along the axial direction of the piston body 40), a length (dimension along the circumferential direction of the piston body 40) and a width (along the radial direction of the piston body 40) It is configured in a plate shape smaller than the dimensions).
- the outer end 46 a of the magnet 46 is disposed in the notch 58 c of the holding member 44. In other words, the outer end 46 a of the magnet 46 is disposed within the range of the thickness of the circumferential portion 57.
- the outer end 46 a of the magnet 46 is directly opposed to the inner peripheral surface of the cylinder tube 12.
- the magnet 46 is, for example, a ferrite magnet, a rare earth magnet, a plastic magnet or the like.
- the first yoke 47 is formed in a continuous ring shape without break in the circumferential direction.
- the first yoke 47 is disposed on one axial direction side (arrow X1 direction side) of the plurality of magnets 46.
- the outer diameter of the first yoke 47 is larger than the outer diameter of the first small diameter portion 40a2 of the first piston member 40a (the bottom surface of the packing attachment groove 50).
- the first yoke 47 is disposed adjacent to an end face of the first piston member 40 a on the second piston member 40 b side (arrow X 2 direction side).
- the inner circumferential surface of the first yoke 47 is located radially inward of the inner end 46 b of the magnet 46.
- the outer peripheral surface of the first yoke 47 is located radially outward of the outer end 46 a of the magnet 46.
- the second small diameter portion 40b1 of the second piston member 40b is inserted into the hole of the first yoke 47.
- the second yoke 48 is formed in a continuous ring shape without break in the circumferential direction.
- the second yoke 48 is disposed on the other side (the arrow X2 direction side) of the plurality of magnets 46 in the axial direction.
- the outer diameter of the second yoke 48 is larger than the outer diameter of the second large diameter portion 40b2 of the second piston member 40b.
- the second yoke 48 is disposed adjacent to an end face of the second piston member 40 b on the first piston member 40 a side (arrow X 1 direction side).
- the inner circumferential surface of the second yoke 48 is located radially inward of the inner end 46 b of the magnet 46.
- the outer peripheral surface of the second yoke 48 is located radially outward of the outer end 46 a of the magnet 46.
- the second yoke 48 has a ring-shaped adjacent portion 48a adjacent to the plurality of magnets 46, and a ring-shaped axial portion protruding from the outer peripheral portion of the adjacent portion 48a in the axial direction (direction of arrow X2) separated from the first yoke 47 And 48b. Therefore, the second yoke 48 has an L-shaped cross-sectional shape.
- the second small diameter portion 40b1 of the second piston member 40b is inserted into the hole of the second yoke 48 (the hole of the axial portion 48b).
- the circumferential portion 57 of the holding member 44 is supported by the outer circumferential surface of the axial portion 48 b of the second yoke 48. That is, the circumferential portion 57 of the holding member 44 overlaps the radially outer side of the axial portion 48 b of the second yoke 48.
- a magnetic body which comprises the 1st yoke 47 and the 2nd yoke 48 soft magnetic materials, such as stainless steel, are mentioned, for example.
- the plurality of magnets 46, the first yoke 47 and the second yoke 48 form a ring-shaped magnetic structure 49 that forms a magnetic field over the entire circumference of the piston unit 18.
- the number of magnets 46 may be three or less or five or more, but it is preferable that four or more magnets 46 be arranged so that a magnetic field can be reliably formed over the entire circumference of the piston unit 18 .
- a magnetic sensor 64 is attached to the outside of the cylinder tube 12. Specifically, the sensor bracket 66 is attached to the connection rod 32 (FIG. 1). A magnetic sensor 64 is held by the sensor bracket 66. Thus, the position of the magnetic sensor 64 is fixed to the head cover 16 and the rod cover 14 via the sensor bracket 66 and the connection rod 32. The magnetic sensor 64 senses the magnetism generated by the magnet 46 to detect the operating position of the piston unit 18.
- the piston rod 20 is a columnar (cylindrical) member extending along the axial direction of the slide hole 13.
- the piston rod 20 passes through the rod cover 14.
- the tip 20 b of the piston rod 20 is exposed to the outside of the sliding hole 13.
- a first cushion ring 69 a is fixed to the outer peripheral portion of the piston rod 20 at a position adjacent to the rod cover 14 side of the piston main body 40.
- a second cushion ring 69 b is fixed to the piston main body 40 (second piston member 40 b) coaxially with the piston rod 20 on the opposite side of the piston main body 40 from the first cushion ring 69 a.
- the first cushion packing 68a, the second cushion packing 68b, the first cushion ring 69a, and the second cushion ring 69b form an air cushion mechanism that reduces the impact at the stroke end.
- a damper made of an elastic material such as a rubber material may be used, for example, on the inner wall surface 14a of the rod cover 14 and the inner wall surface 16a of the head cover 16 Each may be attached.
- the fluid pressure cylinder 10 configured as described above operates as follows. In the following description, air (compressed air) is used as the pressure fluid, but a gas other than air may be used.
- the fluid pressure cylinder 10 axially moves the piston unit 18 in the slide hole 13 by the action of air which is a pressure fluid introduced through the first port 15 a or the second port 15 b.
- the piston rod 20 connected to the piston unit 18 moves back and forth.
- the first port 15a is opened to the atmosphere, and the pressure fluid is supplied from a pressure fluid supply source (not shown) via the second port 15b. 2 Supply to the pressure chamber 13b. Then, the piston unit 18 is pushed toward the rod cover 14 by the pressure fluid. As a result, the piston unit 18 is displaced (advanced) together with the piston rod 20 toward the rod cover 14.
- the second port 15b is opened to the atmosphere, and pressure fluid is supplied from a pressure fluid supply source (not shown) via the first port 15a to the first pressure chamber. Supply to 13a. Then, the piston body 40 is pushed toward the head cover 16 by the pressure fluid. Thereby, the piston unit 18 is displaced to the head cover 16 side.
- the piston unit 18 abuts on the head cover 16 to stop the retracting operation of the piston unit 18.
- the second cushion ring 69b contacts the inner peripheral surface of the second cushion packing 68b to form an airtight seal at this contact portion, and the air cushion is formed in the second pressure chamber 13b. Is formed.
- the displacement of the piston unit 18 is decelerated near the stroke end on the head cover 16 side, so that the impact when the stroke end is reached is alleviated.
- the fluid pressure cylinder 10 according to the first embodiment has the following effects.
- the plurality of magnets 46 are circumferentially spaced by the holding member 44, and ring-shaped first yoke 47 and second ring 46 are provided on both sides of the plurality of magnets 46.
- a yoke 48 is disposed.
- the plurality of magnets 46, the first yoke 47 and the second yoke 48 form a ring-shaped magnetic structure 49 that forms a magnetic field over the entire circumference of the piston unit 18. Therefore, the magnetic field can be formed over the entire circumference of the piston unit 18 without using the ring-shaped magnet.
- the common magnet 46 can be adopted to fluid pressure cylinders having different cylinder diameters (piston diameters). That is, it is not necessary to use magnets 46 of different sizes for each cylinder diameter.
- magnetic force adjustment is possible with the same thickness (dimension in the axial direction) by changing the number of magnets 46 to be disposed. Furthermore, the larger the cylinder diameter, the smaller the size of the magnet 46 with respect to the cylinder diameter.
- Each of the plurality of magnets 46 is shaped so as to have a short axis and a long axis perpendicular to the axis of the piston body 40, and is held by the holding member 44 such that the long axis is along the circumferential direction of the piston body 40 There is. With this configuration, it is possible to suppress the variation in the magnetic flux density in the circumferential direction of the magnetic field formed on the outside of the piston unit 18.
- the number of the plurality of magnets 46 is four, and the plurality of magnets 46 are arranged at equal intervals in the circumferential direction. With this configuration, it is easy to form a magnetic field whose magnetic flux density is made uniform in the circumferential direction outside the piston unit 18.
- the piston body 40 has a plurality of piston members (a first piston member 40a and a second piston member 40b).
- a ring-shaped receiving groove 52 for receiving the plurality of magnet holding portions 58, the first yoke 47 and the second yoke 48 is formed by the plurality of piston members. With this configuration, the ring-shaped first yoke 47 and the second yoke 48 can be easily assembled on both sides of the plurality of magnets 46 when the piston unit 18 is assembled.
- One side wall of the packing attachment groove 50 is formed by the outer peripheral portion of the first piston member 40a. Further, the other side wall of the packing attachment groove 50 is formed by the outer peripheral portion of the first yoke 47. With this configuration, the ring-shaped packing 42 can be easily assembled, and the axial dimension of the piston main body 40 can be shortened.
- the second yoke 48 has an adjacent portion 48 a adjacent to the plurality of magnets 46 and a ring-shaped axial portion 48 b protruding from the outer peripheral portion of the adjacent portion 48 a in the axial direction away from the first yoke 47. With this configuration, the area of the outer periphery of the second yoke 48 can be increased, and the magnetic flux density of the magnetic field formed outside the piston unit 18 can be effectively increased.
- the holding member 44 is supported by the outer peripheral surface of the axial portion 48 b of the second yoke 48. By this configuration, the holding member 44 can be favorably supported using the axial direction portion 48 b.
- the outer peripheral surface of the first yoke 47 and the outer peripheral surface of the second yoke 48 are located outward from the outer ends 46 a of the plurality of magnets 46. With this configuration, the magnetic flux density of the magnetic field formed outside the piston unit 18 can be effectively increased.
- the magnet holding portion 58 has a notch 58 c opened at the outer peripheral surface of the holding member 44.
- the magnet 46 can be disposed at a position close to the inner circumferential surface of the cylinder tube 12.
- the distance between the magnetic sensor 64 attached to the outside of the cylinder tube 12 and the magnet 46 disposed on the inside of the cylinder tube 12 can be reduced, so the magnetic force required of the magnet 46 can be reduced.
- the axial thickness of the magnet 46 can be reduced. Therefore, the axial dimension of the piston unit 18 can be shortened.
- the holding member 44 is a wear ring 44A configured to prevent the piston body 40 from contacting the cylinder tube 12. Thereby, since the holding member 44 serves both as the member holding the magnet 46 and the wear ring 44A, the configuration can be simplified.
- a cylinder tube 12A shown in FIG. 4 may be employed instead of the cylinder tube 12.
- the cylinder tube 12A is provided with a protrusion 74 extending along the axial direction on a part of the outer peripheral portion.
- a magnetic sensor mounting slot 74a is provided in the projection 74.
- a plate-like (thin) magnetic sensor 64a is inserted into the magnetic sensor mounting slot 74a.
- the magnetic sensor 64a is inserted into the magnetic sensor mounting slot 74a provided close to the inner peripheral surface of the cylinder tube 12A.
- the distance to the magnetic structure 49 (see FIG. 2 etc.) having the plurality of magnets 46 can be further shortened.
- the axial thickness of the magnet 46 can be further effectively reduced.
- a fluid pressure cylinder 10a according to a second embodiment shown in FIG. 5 includes a hollow cylindrical cylinder tube 80 having a circular slide hole 13 therein, and a rod cover 82 disposed at one end of the cylinder tube 80.
- a head cover 84 disposed at the other end of the cylinder tube 80, a piston unit 86 disposed movably in the axial direction (X direction) in the cylinder tube 80, and a piston rod 88 coupled to the piston unit 86 Prepare.
- the cylinder tube 80 is formed in a hollow cylindrical shape. Internally threaded portions 90 a and 90 b are formed on inner peripheral surfaces of both ends of the cylinder tube 80. Circular ring-shaped packings 92 a and 92 b are disposed between the cylinder tube 80 and the rod cover 82 and between the cylinder tube 80 and the head cover 84, respectively.
- a magnetic sensor 64 (see FIG. 1 and the like) is attached to an outer peripheral surface of the cylinder tube 80 at an arbitrary position using a band type sensor attachment.
- the sensor attachment includes a sensor holder for holding the magnetic sensor 64 and a band portion for fixing the sensor holder to the outer peripheral portion of the cylinder tube 80.
- An externally threaded portion 94 a formed on the rod cover 82 is in threaded engagement with an internally threaded portion 90 a formed on the inner peripheral surface of one end of the cylinder tube 80.
- the rod cover 82 is formed with a first port 96 a.
- a circular ring-shaped bush 98 and packing 100 are disposed on the inner peripheral portion of the rod cover 82.
- a damper 102 made of an elastic material is attached to the inner wall surface 82 a of the rod cover 82.
- An external thread 94 b formed on the head cover 84 is screwed with an internal thread 90 b formed on the inner peripheral surface of the other end of the cylinder tube 80.
- the head cover 84 is formed with a second port 96 b.
- a damper 104 made of an elastic material is attached to the inner wall surface 84 a of the head cover 84.
- the piston unit 86 has a circular piston main body 106 protruding radially outward from the piston rod 88, a packing 42 mounted on the outer peripheral portion of the piston main body 106, and a holding member 44 mounted on the outer peripheral portion of the piston main body 106. And a plurality of magnets 46 circumferentially spaced on the outer periphery of the piston body 106, and a first yoke 47 and a second yoke 48 disposed adjacent to the plurality of magnets 46.
- the piston body 106 has a first piston member 40 a and a second piston member 107.
- the second piston member 107 differs from the second piston member 40b (FIG. 2) in that the second cushion ring 69b is not fixed.
- the proximal end 88 a of the piston rod 88 is inserted into the through hole 40 h formed in the piston main body 106 and fixed by caulking.
- the fixing structure between the piston main body 106 and the piston rod 88 is not limited to caulking, and may be a screwing-in structure.
- the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the present invention.
- the cylinder tube 12, 80 and the piston unit 18, 86 having a circular cross-sectional shape are adopted, but the present invention is not limited thereto, the cross-sectional shape is non-circular (elliptical shape , An elliptical shape, a polygonal shape, etc.) and a cylinder unit and a piston unit may be adopted.
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- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Actuator (AREA)
- Pistons, Piston Rings, And Cylinders (AREA)
Abstract
Description
Claims (11)
- シリンダチューブに形成された摺動孔に沿って往復移動可能なピストンユニットであって、
ピストン本体と、
前記ピストン本体の外周部に装着されたパッキンと、
前記ピストン本体の外周部に装着されるとともに、周方向に配列された複数のマグネット保持部を有する保持部材と、
前記複数のマグネット保持部により周方向に間隔を置いて保持された複数のマグネットと、
前記複数のマグネットの軸方向一方側に配置されたリング状の第1ヨークと、
前記複数のマグネットの軸方向他方側に配置されたリング状の第2ヨークと、を備える、
ことを特徴とするピストンユニット。 - 請求項1記載のピストンユニットにおいて、
前記複数のマグネットの各々は、前記ピストン本体の軸に対して垂直な短軸及び長軸を有する形状であるとともに、前記長軸が前記ピストン本体の周方向に沿うように前記保持部材に保持されている、
ことを特徴とするピストンユニット。 - 請求項1記載のピストンユニットにおいて、
前記複数のマグネットの数は、4個であり、
前記複数のマグネットは、周方向に等間隔に配置されている、
ことを特徴とするピストンユニット。 - 請求項1記載のピストンユニットにおいて、
前記ピストン本体は、複数のピストン部材を有し、
前記複数のピストン部材により、前記複数のマグネット保持部、前記第1ヨーク及び前記第2ヨークを収容するリング状収容溝が形成されている、
ことを特徴とするピストンユニット。 - 請求項4記載のピストンユニットにおいて、
前記ピストン本体の外周部には、前記パッキンが装着されたリング状のパッキン装着溝が形成され、
前記パッキン装着溝の一方の側壁が前記ピストン本体によって形成され、
前記パッキン装着溝の他方の側壁が前記第1ヨークの外周部によって形成されている、
ことを特徴とするピストンユニット。 - 請求項1記載のピストンユニットにおいて、
前記第2ヨークは、
前記複数のマグネットに隣接した隣接部と、
前記第1ヨークから離れる軸方向に前記隣接部の外周部から突出したリング状の軸方向部と、を有する、
ことを特徴とするピストンユニット。 - 請求項6記載のピストンユニットにおいて、
前記保持部材は、前記第2ヨークの前記軸方向部の外周面によって支持されている、
ことを特徴とするピストンユニット。 - 請求項1記載のピストンユニットにおいて、
前記第1ヨークの外周面及び前記第2ヨークの外周面は、前記複数のマグネットの各外端よりも外方に位置している、
ことを特徴とするピストンユニット。 - 請求項1記載のピストンユニットにおいて、
前記マグネット保持部は、前記保持部材の外周面にて開口した切欠部を有する、
ことを特徴とするピストンユニット。 - 請求項1記載のピストンユニットにおいて、
前記保持部材は、前記ピストン本体が前記シリンダチューブに接触することを阻止するように構成されたウエアリングである、
ことを特徴とするピストンユニット。 - 内部に摺動孔を有するシリンダチューブと、前記摺動孔に沿って往復移動可能に配置されたピストンユニットと、前記ピストンユニットから軸方向に突出したピストンロッドと、を備えた流体圧シリンダであって、
前記ピストンユニットは、
ピストン本体と、
前記ピストン本体の外周部に装着されたパッキンと、
前記ピストン本体の外周部に装着されるとともに、周方向に配列された複数のマグネット保持部を有する保持部材と、
前記複数のマグネット保持部により周方向に間隔を置いて保持された複数のマグネットと、
前記複数のマグネットの軸方向一方側に配置されたリング状の第1ヨークと、
前記複数のマグネットの軸方向他方側に配置されたリング状の第2ヨークと、を備える、
ことを特徴とする流体圧シリンダ。
Priority Applications (6)
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KR1020207009971A KR102305427B1 (ko) | 2017-09-07 | 2018-07-06 | 피스톤 유닛 및 유체압 실린더 |
MX2020002497A MX2020002497A (es) | 2017-09-07 | 2018-07-06 | Unidad de piston y cilindro hidraulico. |
US16/644,049 US11215204B2 (en) | 2017-09-07 | 2018-07-06 | Piston unit and hydraulic cylinder |
CN201880057826.8A CN111051708B (zh) | 2017-09-07 | 2018-07-06 | 活塞单元及流体压力缸 |
BR112020004580-2A BR112020004580A2 (pt) | 2017-09-07 | 2018-07-06 | unidade de pistão e cilindro hidráulico |
EP18854089.2A EP3680495B1 (en) | 2017-09-07 | 2018-07-06 | Piston unit and hydraulic cylinder |
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JP2017172265A JP6808183B2 (ja) | 2017-09-07 | 2017-09-07 | ピストンユニット及び流体圧シリンダ |
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TW201912958A (zh) | 2019-04-01 |
KR20200047683A (ko) | 2020-05-07 |
KR102305427B1 (ko) | 2021-09-27 |
MX2020002497A (es) | 2020-07-20 |
TWI686545B (zh) | 2020-03-01 |
EP3680495A1 (en) | 2020-07-15 |
EP3680495B1 (en) | 2022-11-02 |
BR112020004580A2 (pt) | 2020-09-08 |
CN111051708A (zh) | 2020-04-21 |
JP6808183B2 (ja) | 2021-01-06 |
US20200248728A1 (en) | 2020-08-06 |
CN111051708B (zh) | 2021-11-02 |
US11215204B2 (en) | 2022-01-04 |
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JP2019044948A (ja) | 2019-03-22 |
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