JP5001315B2 - Fluid pressure cylinder - Google Patents

Description

  The present invention relates to a fluid pressure cylinder configured such that a piston rod can be projected and retracted from inside a cylinder tube while performing linear motion and rotational motion.

  Since the workpiece is clamped or unclamped using the fluid pressure cylinder, the piston rod is linearly and rotationally moved in the fluid pressure cylinder. An example of such a fluid pressure cylinder is a rotary clamp cylinder disclosed in Patent Document 1. The rotary clamp cylinder disclosed in Patent Document 1 includes a cylinder tube, and a rod cover is fixed to the rod side of the cylinder tube. A piston integral with the piston rod is accommodated in the cylinder tube, and the piston rod is inserted into the rod cover from the cylinder tube. An annular groove is formed on the inner peripheral surface of the tip of the rod cover, and a rod packing is attached to the annular groove. The rod packing allows the inner surface of the rod cover to face the peripheral surface of the piston rod. Airtightness between the surfaces is maintained.

  A guide pin is inserted into the insertion hole formed in the side portion of the cylinder tube, and a curved guide groove including a parallel portion and a spiral portion is formed on the outer peripheral surface of the piston rod. The tip of the guide pin is engaged in the guide groove. When the fluid is supplied to and discharged from the cylinder tube, the piston rod moves linearly when the guide pin is engaged with the parallel part of the guide groove, and the piston rod moves in and out of the cylinder tube. The workpiece is unclamped or clamped by. On the other hand, when the guide pin is engaged with the spiral portion of the guide groove, the piston rod performs a linear motion and a rotational motion. Rotation is performed.

Japanese Utility Model Publication No. 5-52305

  In the rotary clamp cylinder of Patent Document 1, a guide groove is formed on the outer peripheral surface of the piston rod in order to realize linear motion and rotational motion of the piston rod. Here, if the guide groove passes through the inside of the rod packing during the movement of the piston rod, fluid (air) leaks from the guide groove, and the sealing performance between the piston rod and the rod cover cannot be maintained. For this reason, in the rotary clamp cylinder of patent document 1, in order to maintain sealing performance, the rod packing is always disposed at a position escaped from the guide groove. And in patent document 1, even when a piston rod is located in the stroke end of a protrusion direction, in order to arrange | position a rod packing in the position which escaped from the guide groove, it is not necessary to provide a rod packing in the rod cover extended from the cylinder tube. The entire length of the rotary clamp cylinder was long.

  The present invention has been made paying attention to such problems existing in the prior art, and the purpose thereof is a circumferential surface of a piston rod that performs linear motion and rotational motion, and a portion that faces the circumferential surface. An object of the present invention is to provide a fluid pressure cylinder capable of shortening the overall length while sealing with a rod packing.

  In order to solve the above problems, the invention according to claim 1 is a fluid pressure cylinder configured such that a piston rod can be projected and retracted from a cylinder tube while performing linear motion and rotational motion, and the piston rod includes: A linear portion extending linearly along the axial direction of the piston rod and a spiral portion extending spirally from the linear portion are formed, and the linear portion slides into the cylinder tube so that the piston rod is linearly connected. A guide portion is provided for guiding the rotational motion to the piston rod by guiding the motion while sliding the spiral portion, and the spiral portion of the piston rod at a stroke end in a protruding direction from the cylinder tube. A rod packing that seals between the circumferential surface of the linear portion and the portion facing the circumferential surface is disposed at a position closer to the linear portion than the linear portion. While being, and summarized in that the rod packing are disposed so as to rotate following the rotational movement of the piston rod.

  According to a second aspect of the present invention, in the fluid pressure cylinder according to the first aspect, a rod metal that rotates following the rotational movement of the piston rod is disposed in the cylinder tube, and the rod metal The gist of the invention is that the rod packing is mounted in a mounting groove formed on the inner peripheral surface.

  According to a third aspect of the present invention, in the fluid pressure cylinder according to the second aspect, the rod metal is positioned outside the cylinder tube along the axial direction of the cylinder tube by a positioning member provided on the inner peripheral surface of the cylinder tube. The gist is that the movement toward is restricted and a bearing is interposed between the positioning member and the rod metal.

  According to a fourth aspect of the present invention, in the fluid pressure cylinder according to any one of the first to third aspects, the guide portion is a pair of guide pins arranged to face each other at a position where the piston rod is sandwiched. The gist of this is.

  According to the present invention, the entire length can be shortened while sealing between the circumferential surface of the piston rod that performs linear motion and rotational motion and the portion facing the circumferential surface by the rod packing.

The partially broken perspective view which shows the rotary clamp cylinder of embodiment. The disassembled perspective view which shows a piston rod, a piston, rod packing, a rod metal, and a sliding bearing. (A) is sectional drawing which shows the state which the piston rod protruded, (b) is sectional drawing which shows the state in which the piston rod was immersed.

Hereinafter, an embodiment in which the fluid pressure cylinder of the present invention is embodied as a rotary clamp cylinder will be described with reference to FIGS.
As shown in FIG. 1, the rotary clamp cylinder 11 is formed by a cylinder tube 12, and the cylinder tube 12 is made of an aluminum alloy. A first supply / discharge port 12a is formed at a position near one axial end of the cylinder tube 12, and a second supply / discharge port 12b is formed at a position near the other axial end of the cylinder tube 12. . In addition, the other end side in the axial direction of the cylinder tube 12 is sealed by the bottom portion 12 c, and a rod metal 14 is disposed on the inner side of the one end side in the axial direction of the cylinder tube 12.

  The rod metal 14 is restricted from moving from the inside of the cylinder tube 12 to the outside of the cylinder tube 12 along the axial direction of the cylinder tube 12 by a circlip 15 as a positioning member. The rod metal 14 is accommodated in the cylinder tube 12 so as to be rotatable. A sliding bearing 13 is interposed between the end surface of the rod metal 14 and the circlip 15. As shown in FIG. 2, the slide bearing 13 is formed in an annular shape from a thin plate, and the end surface of the slide bearing 13 that faces the circlip 15 and the rod metal 14 is coated to improve the slip. ing. A rubber O-ring 16 is attached to the outer peripheral surface of the rod metal 14.

  As shown in FIGS. 3A and 3B, a piston 26 that is movable along the axial direction of the cylinder tube 12 is accommodated in the cylinder tube 12 by fluid pressure (air in the present embodiment). Yes. The piston 26 has an annular shape and is fitted into a protrusion 18a formed on the piston rod 18 so that the piston 26 and the piston rod 18 can move together. An annular adapter 17 is fitted on the protrusion 18a, and an annular magnet 27 for detecting the piston position is attached to the outer peripheral surface of the adapter 17 so as to be sandwiched between the piston 26 and the adapter 17. Has been. Further, a cushion member 28 made of an elastic body such as rubber is attached to an end portion of the piston 26 facing the bottom portion 12c. In addition, an annular cushion member 35 made of an elastic body such as rubber is externally fitted to the end of the protrusion 18a closer to the piston rod 18 than the piston 26.

  The piston 26 partitions the inside of the cylinder tube 12 into a first pressure working chamber 19 and a second pressure working chamber 20. The first pressure working chamber 19 communicates with the first supply / discharge port 12 a of the cylinder tube 12, and the second pressure working chamber 20 communicates with the second supply / discharge port 12 b.

  The piston rod 18 has a linear portion 18b that extends linearly along the direction in which the central axis L extends (hereinafter, referred to as the axial direction of the piston rod 18), and a spiral that spirally extends around the central axis L of the piston rod 18. The above-mentioned protrusion 18a that protrudes from the portion 18c and the spiral portion 18c is integrally provided. A pair of first sliding contact surfaces M <b> 1 is formed on the linear portion 18 b of the piston rod 18. The pair of first sliding contact surfaces M <b> 1 are formed so as to face each other in a direction orthogonal to the axial direction of the piston rod 18 and to extend in a planar shape in the axial direction of the piston rod 18. The pair of first sliding contact surfaces M <b> 1 are formed so as to extend in parallel with each other along the axial direction of the piston rod 18.

  A pair of second sliding contact surfaces M <b> 2 is formed in the spiral portion 18 c of the piston rod 18. The pair of second sliding contact surfaces M <b> 2 are formed so that a cross-sectional view orthogonal to the axial direction of the piston rod 18 has an arc shape and faces in a direction orthogonal to the axial direction of the piston rod 18. Further, each of the pair of second sliding contact surfaces M2 is formed so as to continuously extend from the end of the straight portion 18b to the end of the spiral portion 18c. In the spiral portion 18c, the second slidable contact surface M2 is formed so as to extend spirally around the central axis L as it approaches the protruding portion 18a from the straight portion 18b. The second sliding contact surface M2 is inclined 90 ° at the end with respect to the start end of the spiral portion 18c.

  The piston rod 18 is rotatably supported by the rod metal 14 while the straight portion 18 b is inserted into the rod metal 14. A clamp arm 32 having a thin plate shape is fixed to the tip of the linear portion 18b protruding from the rod metal 14 to the outside. A mounting groove 14a is formed on the inner peripheral surface of the rod metal 14 so as to extend over the entire circumference of the rod metal 14, and a rubber rod packing 34 is mounted on the mounting groove 14a.

  As shown in FIG. 2, the rod packing 34 is a deformed packing formed so that the inner peripheral shape thereof is along the peripheral surface of the linear portion 18 b of the piston rod 18. The inner circumferential shape of the rod packing 34 is formed so that each side extending along the pair of first sliding contact surfaces M1 extends linearly, and in an arc shape connecting the pair of first sliding contact surfaces M1. It is formed so as to extend in an arc shape along each of a pair of extending sides. That is, the inner peripheral shape of the rod packing 34 is formed in the same shape as the cross-sectional shape orthogonal to the axial direction of the linear portion 18b so that the inner peripheral edge of the rod packing 34 is in close contact with the peripheral surface of the linear portion 18b. On the other hand, the outer peripheral shape of the rod packing 34 is formed in a circular shape so as to be in close contact with the inner peripheral surface of the mounting groove 14 a of the rod metal 14.

  As shown in FIGS. 3A and 3B, the linear portion 18 b is inserted inside the rod packing 34 mounted in the mounting groove 14 a of the rod metal 14, and the mounting groove is mounted by the rod packing 34. The space between the inner peripheral surface of 14a and the peripheral surface of the linear portion 18b facing the inner peripheral surface is kept airtight (sealed). Further, in a state where the linear portion 18 b is inserted into the rod packing 34, the rod packing 34 rotates following the rotation of the piston rod 18.

  As shown in FIG. 1, in the cylinder tube 12, a pair of guide pins 30 serving as guide portions are provided at a certain interval closer to the rod metal 14 than the central portion in the axial direction of the cylinder tube 12. Each of the pair of guide pins 30 has a cylindrical shape and is fixed to the inner peripheral surface of the cylinder tube 12. The interval between the pair of guide pins 30 is set to be slightly larger than the maximum width of the straight portion 18b and the spiral portion 18c.

  Next, the operation of the rotary clamp cylinder 11 configured as described above will be described. As shown in FIG. 3A, in a state before the workpiece (not shown) is clamped by the clamp arm 32, the piston 26 moves until the cushion member 35 contacts the guide pin 30, and the piston rod 18 moves in the protruding direction. It has moved to the stroke end. At this time, the rod packing 34 is disposed closer to the linear portion 18b than the spiral portion 18c in the protruding direction of the piston rod 18, and the rod packing 34 is in close contact with the peripheral surface of the linear portion 18b. Further, most of the straight portion 18 b of the piston rod 18 protrudes from the cylinder tube 12. The clamp arm 32 is assumed to be at a position far away from the cylinder tube 12.

  Air is supplied to the first pressure working chamber 19 through the first supply / discharge port 12a, and air from the second pressure working chamber 20 is discharged through the second supply / discharge port 12b. At this time, the rod packing 34 is disposed closer to the linear portion 18b than the spiral portion 18c in the projecting direction of the piston rod 18, and the rod packing 34 is in close contact with the peripheral surface of the linear portion 18b. Airtightness between the surface and the peripheral surface of the straight portion 18b is maintained.

  And the force which presses toward the bottom part 12c acts on piston 26 with air. Then, the piston 26 moves toward the bottom 12c, and the piston rod 18 moves in the immersion direction. When the second slidable contact surface M2 of the spiral portion 18c slidably contacts the guide pin 30, the piston rod 18 performs a rotational motion while performing a linear motion in the immersion direction. Then, the clamp arm 32 rotates toward the workpiece while moving toward the cylinder tube 12.

  During the linear movement of the piston rod 18, the circumferential surface of the linear portion 18b is in sliding contact with the inner circumferential surface of the rod packing 34, so that the inner circumferential surface of the rod packing 34 is maintained in close contact with the circumferential surface of the linear portion 18b. The airtightness between the inner peripheral surface of the mounting groove 14a and the peripheral surface of the linear portion 18b is maintained. Further, during the rotational movement of the piston rod 18, the rod packing 34 and the rod metal 14 rotate following the rotation of the piston rod 18. For this reason, the state where the inner peripheral surface of the rod packing 34 is in close contact with the peripheral surface of the linear portion 18b is maintained, and even if the piston rod 18 rotates, the inner peripheral surface of the mounting groove 14a and the linear portion 18b Airtightness with the peripheral surface is maintained.

  When the spiral portion 18 c passes between the guide pins 30, the piston 26, the piston rod 18, and the clamp arm 32 are rotated by 90 ° immediately after the start of movement, and the clamp arm 32 is disposed immediately above the workpiece. Thereafter, as shown in FIG. 3B, when the first sliding contact surface M1 of the linear portion 18b is in sliding contact with the guide pin 30, the piston rod 18 performs only linear motion in the immersion direction. At this time, since the circumferential surface of the linear portion 18b is in sliding contact with the inner circumferential surface of the rod packing 34, the state where the inner circumferential surface of the rod packing 34 is in close contact with the circumferential surface of the linear portion 18b remains maintained. The airtightness between the inner peripheral surface of the groove 14a and the peripheral surface of the linear portion 18b is maintained.

  When the piston rod 18 reaches the stroke end in the immersion direction and the cushion member 28 comes into contact with the bottom 12c, the clamp arm 32 performs a predetermined clamping operation to clamp a workpiece (not shown).

  On the other hand, after the piston rod 18 reaches the stroke end in the immersion direction, air is supplied to the second pressure working chamber 20 through the second supply / discharge port 12b and the first through the first supply / discharge port 12a. When the air in the pressure working chamber 19 is discharged, a force that presses against the rod metal 14 acts on the piston 26. Then, the piston 26 moves toward the rod metal 14 and the piston rod 18 moves in the protruding direction. And if the 1st sliding contact surface M1 of the linear part 18b slidably contacts with respect to the guide pin 30, the piston rod 18 will perform a linear motion to a protrusion direction. Then, the clamp arm 32 moves in a direction away from the cylinder tube 12. Thereafter, when the second slidable contact surface M2 of the spiral portion 18c is slidably contacted with the guide pin 30, the piston rod 18 performs a rotational motion while performing a linear motion in the protruding direction. Then, the clamp arm 32 rotates in a direction away from the workpiece while moving in a direction away from the cylinder tube 12.

  When the piston rod 18 is moved in the immersion direction, the peripheral surface of the linear portion 18b is slidably contacted with the inner peripheral surface of the rod packing 34, and the rod packing 34 and the rod The metal 14 rotates. For this reason, the state where the inner peripheral surface of the rod packing 34 is in close contact with the peripheral surface of the straight portion 18b is maintained, and the airtightness between the inner peripheral surface of the mounting groove 14a and the peripheral surface of the straight portion 18b is maintained. Is done.

  As shown in FIG. 3A, when the piston 26 reaches the stroke end in the protruding direction and the cushion member 35 contacts the guide pin 30, the clamp arm 32 is rotated by 90 ° immediately after the start of movement. . At this time, the rod packing 34 is disposed closer to the linear portion 18b than the spiral portion 18c in the projecting direction of the piston rod 18, and the rod packing 34 is in close contact with the peripheral surface of the linear portion 18b. Airtightness between the surface and the peripheral surface of the straight portion 18b is maintained. The clamp arm 32 performs a predetermined unclamping operation to unclamp a workpiece (not shown).

According to the above embodiment, the following effects can be obtained.
(1) In order to cause the piston rod 18 to perform linear motion and rotational motion, the piston rod 18 is formed with a linear portion 18b and a spiral portion 18c, and a guide pin 30 for guiding the linear motion and rotational motion to the piston rod 18 is provided in the cylinder. It was provided in the tube 12. Further, a rod packing 34 made of a deformed packing along the peripheral surface of the straight portion 18b is provided so as to follow the rotation of the piston rod 18, and from the helical portion 18c of the piston rod 18 at the stroke end in the protruding direction. A rod packing 34 is disposed on the straight portion 18b side. For this reason, when the piston rod 18 is positioned at the stroke end in the protruding direction, the rod packing 34 made of a deformed packing holds the space between the circumferential surface of the non-circular linear portion 18b and the mounting groove 14a (seal) can do. Further, since the rod packing 34 rotates following the piston rod 18, airtightness can be maintained (sealed) by the rod packing 34 even while the piston rod 18 is rotating.

  Therefore, according to the rotary clamp cylinder 11 of the present embodiment, when the piston rod 18 is positioned at the stroke end in the protruding direction, it is not necessary to dispose the rod packing 34 at a position where it escapes from the linear portion 18b. Thus, there is no need to arrange the rod packing on the rod cover extended from the cylinder tube. That is, since the rotary clamp cylinder 11 can arrange | position the rod packing 34 in the cylinder tube 12, compared with the case where a rod cover is required like background art, the full length of the rotary clamp cylinder 11 can be shortened. it can.

(2) A rod packing 34 made of a deformed packing is provided in the cylinder tube 12 so as to rotate following the rotation of the piston rod 18. For this reason, unlike the background art, when the piston rod 18 is positioned at the stroke end in the protruding direction, it is not necessary to dispose the rod packing 34 at a position where the rod packing 34 escapes from the straight portion 18b. Therefore, even if the entire length of the linear portion 18b is extended in order to lengthen the stroke of the piston rod 18, it can be dealt with without changing the arrangement position of the rod packing 34.

(3) A rod packing 34 made of a deformed packing is provided in the cylinder tube 12 so as to rotate following the rotation of the piston rod 18. For this reason, unlike the background art, when the piston rod 18 is positioned at the stroke end in the protruding direction, it is not necessary to dispose the rod packing 34 at a position where the rod packing 34 escapes from the straight portion 18b. Therefore, it is not necessary to set the arrangement position of the rod packing 34 accurately, and the production of the rotary clamp cylinder 11 can be facilitated.

(4) A rod packing 34 made of a deformed packing is provided in the cylinder tube 12 so as to rotate following the rotation of the piston rod 18. Therefore, unlike the background art, when the piston rod 18 is positioned at the stroke end in the protruding direction, it is not necessary to dispose the rod packing 34 at a position where the rod packing 34 escapes from the linear portion 18b. Therefore, the rotary clamp cylinder 11 of the present embodiment does not require a rod cover on the cylinder tube 12 as in the background art, and can simplify the assembly of the rotary clamp cylinder 11.

  (5) In the cylinder tube 12, the rod metal 14 is disposed so as to rotate following the piston rod 18, and a rod packing 34 is mounted in the mounting groove 14 a of the rod metal 14. Then, following the rotation of the piston rod 18, the rod metal 14 and the rod packing 34 rotate. Therefore, by holding the rod packing 34 with the rod metal 14, the rod packing 34 can be easily rotated following the piston rod 18, and airtightness by the rod packing 34 can be reliably held.

  (6) A sliding bearing 13 is interposed between the end face of the rod metal 14 and the circlip 15. For this reason, the rod metal 14 is easily rotated by the slide bearing 13, and the rod metal 14 and the rod packing 34 can be easily rotated following the rotation of the piston rod 18.

  (7) The linear motion and the rotational motion of the piston rod 18 are performed when the first sliding contact surface M1 and the second sliding contact surface M2 are in sliding contact with the pair of guide pins 30. Then, during the rotational movement of the piston rod 18, the load applied to the guide pin 30 from the piston rod 18 can be received by the pair of guide pins 30. Therefore, for example, as compared with the case where only one guide pin 30 is provided, the load resistance of the guide pin 30 can be increased, and the clamp arm 32 that can be fixed to the piston rod 18 can be enlarged.

  (8) The straight portion 18b of the piston rod 18 is composed of a pair of flat first sliding contact surfaces M1 and a circular arc surface, and a cross-sectional view perpendicular to the axial direction of the piston rod 18 is formed in a substantially square shape. ing. Therefore, the inner peripheral shape of the rod packing 34 can also be made substantially rectangular, the sealing performance by the rod packing 34 can be improved, and the piston rod 18 can be easily processed.

In addition, you may change the said embodiment as follows.
In the straight portion 18b and the spiral portion 18c, a concave groove extending along the axial direction of the piston rod 18 is formed on the opposite side surface, and a guide ball engaged with the concave groove is provided in the cylinder tube 12 as a guide portion. May be. In this case, the rod packing 34 is formed of a deformed packing whose inner peripheral shape is along the peripheral surface of the piston rod 18 and is also in close contact with the inner surface of the groove. Then, the piston rod 18 may be caused to perform linear motion and rotational motion by sliding the concave groove against the guide ball.

  The piston rod 18 may be formed so that the cross-sectional view orthogonal to the axial direction has a hexagonal shape. In this case, the rod packing 34 is formed of a deformed packing whose inner peripheral shape forms a hexagonal shape.

○ Only one guide pin 30 may be provided.
○ The sliding bearing 13 may be omitted.
A roller bearing may be provided between the rod metal 14 and the circlip 15 to smoothly rotate the rod metal 14.

○ The rod metal 14 may be omitted.
The fluid pressure cylinder of the present invention is not only used as a rotary clamp cylinder, but may be used for other purposes.

The fluid pressure cylinder of the present invention may be a cylinder that uses a gas other than air, or a hydraulic cylinder that uses liquid instead of gas as a fluid, for example.
Next, the technical idea that can be grasped from the above embodiment and other examples will be described below.

  (1) The linear portion includes a pair of first slidable contact surfaces facing in a direction orthogonal to the axial direction of the piston rod, and the first slidable contact surfaces extend in a planar shape along the axial direction. The fluid pressure cylinder according to any one of claims 1 to 4, wherein the fluid pressure cylinder is formed.

  DESCRIPTION OF SYMBOLS 11 ... Rotary clamp cylinder as a fluid pressure cylinder, 12 ... Cylinder tube, 13 ... Sliding bearing as a bearing, 14 ... Rod metal, 14a ... Mounting groove, 15 ... Circlip as positioning member, 18 ... Piston rod, 18b ... Linear part, 18c ... Spiral part, 30 ... Guide pin as guide part, 34 ... Rod packing.

Claims (4)

A fluid pressure cylinder configured such that the piston rod can be moved in and out of the cylinder tube while performing linear motion and rotational motion,
A linear portion extending linearly along the axial direction of the piston rod and a spiral portion extending spirally from the linear portion are formed on the piston rod,
In the cylinder tube, there is provided a guide portion that guides a linear motion to the piston rod by sliding the linear portion while sliding a spiral motion to guide the rotational motion to the piston rod.
Further, at a position closer to the linear portion side than the spiral portion of the piston rod at the stroke end in the protruding direction from the cylinder tube, between the peripheral surface of the linear portion and a portion facing the peripheral surface. A fluid pressure cylinder in which a rod packing for sealing is disposed and the rod packing is rotated so as to follow the rotational movement of the piston rod.   A rod metal that rotates following the rotational movement of the piston rod is disposed in the cylinder tube, and the rod packing is mounted in a mounting groove formed on an inner peripheral surface of the rod metal. Item 2. The fluid pressure cylinder according to Item 1.   The movement of the rod metal toward the outside of the cylinder tube along the axial direction of the cylinder tube is restricted by a positioning member provided on the inner peripheral surface of the cylinder tube, and between the positioning member and the rod metal The fluid pressure cylinder according to claim 2, wherein a bearing is interposed.   The fluid pressure cylinder according to any one of claims 1 to 3, wherein the guide portion includes a pair of guide pins arranged to face each other at a position sandwiching the piston rod.

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