JP3849522B2 - Fluid pressure cylinder - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fluid pressure cylinder in which a fluid passage in a cylinder axial direction is formed between a concave groove formed in an inner peripheral surface of a bore of an outer tube and an outer periphery of an inner tube fitted in the bore.
[0002]
[Prior art]
A single groove is formed along the axial direction in the bore of the cylinder case whose head side is closed with a member formed integrally with the outer tube, and the inner tube is fitted into the bore so that the outer peripheral surface of the inner tube and the groove are A rod-side cylinder chamber defined by one of a pair of fluid supply / discharge ports provided in a portion that forms a fluid passage between them and closes the head side, and a piston slidably fitted inside the inner tube Are communicated through the fluid passage (Japanese Utility Model Laid-Open No. 3-78102).
[0003]
[Problems to be solved by the invention]
In the above structure, there is an advantage that a long fluid passage in the cylinder case does not need to be machined, so that the number of processing steps is reduced. However, since there is only one fluid passage, in order to ensure a constant flow rate A relatively deep groove is required. Therefore, in the prior art, the wall pressure of the outer tube is partially increased, and there is a problem that the wall pressure of the outer tube cannot be reduced. In addition, since the pressurized fluid is supplied to the rod side through one fluid passage, the pressure from the outer side to the inner side in the radial direction is limited to only one portion where the fluid passage is formed on the outer peripheral surface of the inner tube. As a result, a part of the inner tube in the circumferential direction tends to be greatly deformed, and the smooth movement of the piston sliding inside the inner tube may be hindered.
An object of the present invention is to provide a fluid pressure cylinder having a structure capable of reducing the wall pressure of the outer tube even if a flow path that allows a constant flow rate to pass is formed. Another object of the present invention is to provide a fluid pressure cylinder that makes the deformation of the inner tube uniform by the fluid pressure passing through the flow path and smoothes the sliding of the piston. Furthermore, the present application is to provide a cylinder structure in which an inner tube can be easily attached and an annular groove that communicates a plurality of flow paths and supply / discharge ports can be easily formed.
[0004]
[Means for Solving the Problems]
In order to solve the above problem, the fluid pressure cylinder of the present application forms a longitudinal groove in the bore of the outer tube, and inserts the inner tube into the bore so that the longitudinal tube is inserted between the outer circumferential surface of the inner tube and the groove. A fluid passage is formed, a piston is fitted into the inner tube so as to be movable in the axial direction, and the cylinder chamber inside the inner tube is divided into a rod side and a head side, and either the rod side or the head side of the tube is blocked. A pair of supply / discharge ports are provided on the side, and one of the supply / discharge ports communicates with the cylinder chamber on the side where the supply / discharge ports are not provided via the fluid passage. The other supply / discharge port is connected to the supply / discharge port. In the fluid pressure cylinder connected to the cylinder chamber on the provided side, a plurality of concave grooves are formed in the outer tube bore in the circumferential direction of the outer tube so as to extend longitudinally from the outer surface of the inner tube. A fluid passage direction forming a plurality, in the rod cover, to form a tube fitting groove receiving an end portion of the outer tube and the inner tube, the tube fitting groove, and the end fitting portion of the outer tube, a smaller diameter than that The inner tube has a stepped shape consisting of an inner tube end receiving portion larger than the outer diameter of the inner tube, and the inner tube is inserted into the inner tube by protruding the rod side end from the rod side end of the outer tube toward the rod side. The tube end receiving part, the inner tube end outer periphery and the outer tube end surface form an annular communication path, and the external thread end provided on the rod side end outer periphery of the outer tube is fitted to the outer tube end part of the rod cover. The outer tube and the rod cover are fixed together by screwing into the female thread provided at the joint, and the outer tube bore head is fixed. Screw the male screw provided on the outer periphery of the head cover to the female screw provided on the side end to fix the outer tube and the head cover together, and insert the inner tube between the head cover and the rod cover from both sides in the axial direction. The one supply / discharge port is communicated with each fluid passage through a communication passage that communicates axial ends of the plurality of fluid passages on the one supply / discharge port side.
According to this, since a constant flow rate can be ensured by a plurality of fluid passages, each concave groove constituting each fluid passage may be a shallow groove as compared with the conventional case in which only one concave groove is provided. The tube pressure can be reduced. Also, in order to fix the head cover and rod cover to the cylinder tube, the outer tube does not require an extra wall thickness compared to the case where these covers are tightened against the cylinder tube using axial tightening bolts. The overall thickness can be made extremely thin. Also, a pair of supply / discharge ports is formed in the rod cover, and a tube fitting groove for receiving the end portions of the outer tube and the inner tube is formed in the rod cover, and the tube fitting groove is fitted to the end portion of the outer tube. And an inner tube end receiving portion with a diameter smaller than that of the inner tube outer diameter, and the rod end of the inner tube protrudes from the rod side end of the outer tube to the rod side. When fitted, an annular communication path is formed by the end receiving portion of the inner tube, the outer periphery of the inner tube end, and the end surface of the outer tube, so if the outer, inner tube and rod cover are assembled, A communication path is formed, and the formation of the communication path is easy.
[0005]
The concave grooves are preferably formed at equiangular intervals in the circumferential direction. According to this, since pressure acts on the outer peripheral surface of the inner tube from the outside at equal angular intervals, the inner tube receives a force uniformly and deforms uniformly.
It is preferable that the rod cover is integrally fixed to the rod side of the outer tube, the head cover is integrally fixed to the head side of the outer tube, and the inner tube is sandwiched between the head cover and the rod cover from both sides of the axis. According to this, no special attachment means is required for fixing the inner tube .
[0006]
DETAILED DESCRIPTION OF THE INVENTION
1 and 2, the cylinder tube 1 is composed of an outer tube 2 and an inner tube 3. The outer tube 2 is made of an aluminum alloy drawing material. As shown in FIGS. 5 and 6, a plurality of (eight) concave grooves 5 are drawn at equal angular intervals in the inner surface of the center hole (bore) 4 in the circumferential direction. Sometimes pre-formed. On the other hand, the inner tube 3 shown in FIG. 4 is made of stainless steel, and a plurality of (four in this case) notches 6 for passing pressurized fluid are formed at equal angular intervals in the circumferential direction at the head side end. ing. The outer peripheral surface of the inner tube 3 is fitted into the bore 4 of the outer tube 2, and eight fluid passages 7 are formed along the longitudinal direction of the cylinder tube 1 by the outer peripheral surface of the inner tube 3 and the plurality of concave grooves 5 of the outer tube 2. Is to be formed. The rod-side and head-side ends of these fluid passages 7 are opened outward from the axis. In the attached state, the rod side end 3 a of the inner tube 3 protrudes a predetermined amount toward the rod side from the rod side end 2 a of the outer tube 2. Therefore, the rod side opening 7a of the fluid passage 7 is located on the head side (downward) in the axial direction from the rod side end 3a of the inner tube 3 (FIG. 7).
[0007]
The cylinder tube 1 includes a head chamber 10 and a rod cover 11, and both ends in the axial direction are closed to form a cylinder chamber 12 inside. A piston 13 is fitted in the cylinder chamber 12 so as to be capable of reciprocating in the axial direction, and the cylinder chamber 12 is partitioned into a head side cylinder chamber 14 and a rod side cylinder chamber 15. The piston 13 is integrally provided with a piston rod 16 on the rod side, and the piston rod 16 projects forward from the rod cover 11 along the axis. A clamper 17 is integrally attached to the protruding portion of the piston rod 16.
[0008]
As shown in FIGS. 1 and 7, the rod cover 11 has an annular tube fitting groove 21 formed on the head side, and a fitting portion 20 in which a radially inner portion is fitted to the inner peripheral surface of the inner tube 3. It has become. The tube fitting groove 21 includes an end fitting portion 21a in which the inner surface of the radially outer wall portion 22 is fitted to the end portion of the outer tube 2, and a diameter smaller than that of the end fitting portion 21a. It has a stepped shape including an end receiving portion 21b that receives the end. The end fitting portion 21a of the outer tube 2 has a female screw portion 21c formed on the head side portion thereof, and a male screw portion 23 formed on the outer periphery of the rod side end portion of the outer tube 2 is screwed to the female screw portion 21c. The rod side end surface 2a of the outer tube 2 is in contact with the stepped portion 21d. In this state, an annular communication path 25 is formed by a space surrounded by the rod-side end outer peripheral surface of the inner tube 3, the end receiving portion 21 b, and the rod-side end face 2 a of the outer tube 2. Is in communication with the rod side openings 7a of the eight fluid passages 7.
[0009]
A pair of supply / discharge ports 30 and 31 are provided on one side surface of the rod cover 11. One supply / discharge port 30 communicates with the annular communication passage 25 via a fluid passage 32. The other supply / discharge port 31 communicates with the rod-side cylinder chamber 15 via another fluid passage 33 of the head cover 10.
[0010]
The head cover 10 includes a head cover main body 35 and a cap 36. The head cover main body 35 has a stepped shape including a large diameter portion 38 having a threaded portion 37 formed on the outer periphery and a fitting portion 39 that fits on the inner periphery of the inner tube 3. The stepped portion is a contact surface 40 in which the head-side end surface 3 b of the inner tube 3, the female screw portion 42 of the outer tube 2, and the stepped portion 43 of the bore 4 are in contact with each other to block the head-side opening 7 b of the fluid passage 7. A circumferential groove 44 is formed with a predetermined width from the contact surface 40 toward the rod. A male screw portion 37 on the outer periphery of the head cover main body 35 is screwed into the female screw portion 42 formed on the inner side of the head side end of the bore 4 of the outer tube 2. When the rod cover 11 and the head cover 10 are integrally screwed to the rod side and the head side of the outer tube 2, the head side end 3b of the inner tube 3 is brought into contact with the contact surface 40, and the rod side end 3a. Is in contact with the bottom surface of the end receiving portion 21b of the rod cover 11 in a state protruding from the rod side end surface of the outer tube 2 and sandwiched between the rod cover 11 and the head cover 10 from both sides of the axis. Is done. The fitting portion 39 of the head cover body 35 to the inner tube 3 is formed with a plurality of (four in this case) concave grooves 46 (FIG. 6) for fluid passage in the circumferential direction. The circumferential groove 44 and the head side cylinder chamber 14 are communicated with each other. The notch 6 of the inner tube 3 opens into the circumferential groove 44, and each notch 6 and each of the plurality of fluid passages 7 are annular grooves 47 formed at positions close to the step portion 43 of the outer tube 2. Communicate with each other. Accordingly, the pressurized fluid supplied from the one supply / discharge port 30 is communicated with the communication passage 25, the plurality of fluid passages 7, the annular groove 47, the notch 6 of the inner tube 3, the circumferential groove 44, and the concave groove of the head cover body 35. It is supplied to the head side cylinder chamber 14 through 46.
[0011]
The cap 36 closes a receiving hole, which will be described later, and has an outer diameter that is somewhat smaller than the fitting portion 39 of the head cover main body 35. In order to allow the pressurized fluid supplied to the head side cylinder chamber 14 to efficiently act on the piston 13, the front surface (rod side surface) of the cap 36 of the head cover 10 is shallow in the radial direction at equiangular intervals in the circumferential direction. A groove 49 and an annular groove 50 on the center side connected to each of the grooves 49 are formed. Even if the end surface on the head side of the piston 13 abuts against the front surface of the cap 36, the pressurized fluid acts on the piston 13 with certainty. ing.
A recess 51 into which a ball holder portion 58 (described later) enters and exits is formed at the rear portion (head side) of the piston 13. The swing operation rod 52 projects rearward and concentrically with the axis of the piston 13. It is attached to. On the outer periphery of the swivel rod 52, two swivel grooves 55 each including an axial cam groove 53 and a cam groove 54 obliquely inclined in the circumferential direction are formed at symmetrical positions.
[0012]
Further, the head cover main body 35 is formed with an accommodation hole 57 of the intermediate member 56 opened to the rod side. The accommodation hole 57 includes a small-diameter ball holder portion 58 and a large-diameter spring receiving portion 59. The intermediate member 56 having a stepped shape is fitted so as to be rotatable and movable in the axial direction. The cap 36 is attached with a screw 60 so as to close the opening of the accommodation hole 57 of the head cover main body 35, and the ball holder portion 58 protrudes from the center hole 36 a of the cap 36 to the rod side. A pair of guide balls 62 as guide members held in a ball holder portion 58 are inserted into the center hole 61 of the intermediate member 56 so as to be movable in the axial direction and the rotational direction, respectively. The turning motion generating mechanism 63 is configured by being guided and engaged with the turning groove 55 of the rod 52 for use.
[0013]
Between the intermediate member 56 and the head cover 10 integrated with the cylinder tube 1, until the intermediate member 56 exceeds a predetermined amount of turning torque (allowable torque) via the turning motion generating mechanism 63, the intermediate member 56. Is coupled to the cylinder tube 1 side, and when a torque exceeding the allowable torque is applied, a clutch mechanism 65 is provided for releasing the coupling of both members and rotating the intermediate member 56 relative to the cylinder tube 1.
[0014]
In the clutch mechanism 65, a V-groove 67 is formed on the head side end surface of the cap 36 as an engaging / disengaging recess extending in the radial direction. An engaging / disengaging ball 68 as an engaging / disengaging member is provided on the end surface of the spring receiving portion 59 of the intermediate member 56 facing the V-groove 67 in the axial direction, and the receiving hole bottom of the head cover 10 and the spring receiving portion of the intermediate member 56 are provided. A disc spring 69 as an urging member for urging the intermediate member 56 in the rod direction is interposed between the portion 59 and the engagement / disengagement ball 68 so that the engagement / disengagement ball 68 can be engaged with and disengaged from the V groove 67 by the spring force. Match. In this configuration, the permissible torque is set by the spring force of the disc spring 69, and the permissible torque is set to a normal operation (by moving the piston 13 in the axial direction by the fluid, the swirl motion generating mechanism 63 performs the third operation. In the operation in which the clamper 17 is turned 90 degrees between the unclamping position A and the clamping position B shown in the drawing and moved in the axial direction), the engagement / disengagement ball 68 does not come off from the V groove 67. While the clamper 17 is turning, a dangerous torque is generated in the intermediate member 56 such that an unexpected external force acts to prevent the turning and damage the guide ball 62 or the guide groove 55 of the turning motion generating mechanism 63. Alternatively, when an unexpected external force is applied to the clamper 17 in the unclamping position and the above dangerous torque is generated in the intermediate member 56, As the intermediate member 56 moves in the circumferential direction, the engagement / disengagement ball 68 rides on the V-groove 67, pushes the intermediate member 56 toward the head against the spring force of the disc spring 69, and the V-groove 67 and the engagement / removal ball 68. The intermediate member 56 is freely rotated in the circumferential direction.
[0015]
In the above configuration, when the fluid is supplied to the rod side cylinder chamber 15 from the state of FIG. 2 in the unclamping position A (the clamper 17 turning position is indicated by a two-dot chain line in FIG. 3), the piston 13 is connected to the piston rod 16 and the clamper 17. Then, it is moved downward along the axis along with the turning rod 52. In normal operation, dangerous torque exceeding the allowable torque does not act on the intermediate member 56 via the turning groove 55 and the guide ball 62, so the V groove 67 and the engagement / disengagement ball 68 are caused by the spring force of the disc spring 69. The intermediate member 56 is integrally coupled to the cylinder tube 1 while maintaining the engagement. As a result, the turning groove 55 of the turning rod 52 is guided by the guide ball 62 on the tube side (fixed side), and the clamper 17 turns 90 degrees while moving downward from the unclamping position A, and thereafter The workpiece W is lowered toward the workpiece W while maintaining the turning position, and the workpiece W is clamped at the clamp position B (FIG. 1).
[0016]
During the turning of the clamper 17 in the clamping operation, for example, when a workpiece transfer robot or the like is present at a position where it should not exist due to malfunction, and interferes with the clamper 17 and prevents the clamper 17 from turning, Is still supplied to the rod-side cylinder chamber 15, and the piston 13 generates an excessively dangerous torque exceeding the allowable torque, which causes the turning groove 55 to turn with respect to the guide ball 62 in an attempt to move downward. Let Then, the intermediate member 56 is rotated by the dangerous torque, and the engagement / disengagement ball 68 rides on the V-groove 67 and depresses the intermediate member 56 toward the head against the spring force of the disc spring 69 to engage / disengage from the V-groove 67. The ball 68 is disengaged, the intermediate member 56 is released from the cylinder tube 1 side, and rotates freely while the turning groove 55 and the guide ball 62 are engaged. As described above, when the torque forcing the turning groove 55 to rotate with respect to the guide ball 62 is applied, the clutch mechanism 65 is operated and the intermediate member 56 is rotated freely. Therefore, the turning motion generating mechanism 63 is generated with an unreasonable torque. Can be prevented from being damaged, and the life of the apparatus can be extended. Needless to say, the same is true when an excessive external force that turns the piston 13 (piston rod 16) is applied via the clamper 17 of the present clamping cylinder at the unclamping position A.
[0017]
Next, the pressure fluid supplied from the supply / discharge port 30 to the clamper 17 at the clamp position A in FIG. 1 is connected to the communication passage 25, the plurality of fluid passages 7, the annular groove 47, and the notch 6 of the inner tube 3. , Are supplied to the head side cylinder chamber 14 via the circumferential groove 44, the concave groove 46 of the head cover main body 35, and the grooves 49, 50, and pushes the piston 13 upward. As a result, the clamper 17 moves straight in the axial direction from the clamp position B in FIG. 3 and then turns 90 degrees toward the unclamp position A while moving further forward in the axial direction and stops there. Since a plurality of fluid passages 7 are formed, a fluid supply amount to be supplied to the head-side cylinder chamber 14 may be ensured by a flow rate that passes through the total cross-sectional area of the plurality of fluid passages 7. The cross-sectional size of the fluid passage 7 may be smaller than that of the conventional case where the number of the fluid passages 7 is limited to one. Therefore, in the double tube type cylinder tube structure, the wall thickness of the outer tube 2 can be reduced, which greatly contributes to the reduction of the cylinder outer diameter. Further, since the plurality of fluid passages 7 are provided at equiangular intervals in the circumferential direction with respect to the cylinder tube, the outer peripheral surface of the inner tube 2 from the radially outer side in the circumferential direction by the fluid pressure passing therethrough. Since the pressure is evenly applied, the inner tube can be deformed evenly as compared with the case of having one fluid passage as in the prior art, and the sliding movement of the piston is not hindered.
[0018]
【The invention's effect】
As described above, in the present invention, a plurality of concave grooves are formed in the outer tube bore in the circumferential direction of the outer tube, and a plurality of longitudinal fluid passages are formed between the inner tube outer peripheral surface and one supply / discharge port. Are connected to each fluid passage through a communication passage that communicates the axial ends of one of the plurality of fluid passages on the side of one supply / discharge port, so that a constant flow rate can be ensured by the plurality of fluid passages, The depth of the groove of the outer tube constituting the fluid passage can be made shallower than before, and as a result, the wall pressure of the outer tube can be reduced and the outer diameter of the outer tube can be reduced. In addition, the external thread provided on the outer periphery of the rod side end of the outer tube is screwed into the female thread provided on the outer tube end fitting portion of the rod cover, so that the outer tube and the rod cover are integrally fixed together. The external thread and the head cover are fixed together by screwing the external thread provided on the outer periphery of the head cover to the female thread provided on the head side end of the tube bore, and the inner tube is inserted between the head cover and the rod cover in both axial directions. Since the head cover and the rod cover are fixed to the cylinder tube, extra cover is attached to the outer tube as compared with the case where these covers are tightened against the cylinder tube using the axial tightening bolts. No thickness is required, and the entire cylinder tube can be made extremely thin. Further, since the plurality of fluid passages are provided at equal angular intervals in the circumferential direction with respect to the cylinder tube, the outer peripheral surface of the inner tube is evenly pressurized from the radially outer side in the circumferential direction by the fluid pressure passing therethrough. In contrast, the inner tube can be evenly deformed and the piston can be smoothly slid with respect to the case of having a single fluid passage as in the prior art. Also, a pair of supply / discharge ports is formed in the rod cover, and a tube fitting groove for receiving the end portions of the outer tube and the inner tube is formed in the rod cover, and the tube fitting groove is fitted to the end portion of the outer tube. And an inner tube end receiving portion with a diameter smaller than that of the inner tube outer diameter, and the rod end of the inner tube protrudes from the rod side end of the outer tube to the rod side. When fitted, an annular communication path is formed by the end receiving portion of the inner tube, the outer periphery of the inner tube end, and the end surface of the outer tube, so if the outer, inner tube and rod cover are assembled, A communication path is formed, and the formation of the communication path is easy.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a clamp cylinder in a clamped state.
FIG. 2 is a longitudinal sectional view showing the same section as FIG. 1, but showing an unclamped state.
3 is a plan view of FIG. 1. FIG.
FIG. 4 is a longitudinal sectional view of an inner tube.
FIG. 5 is an enlarged cross-sectional view taken along line VV in FIG. 1;
6 is a cross-sectional view taken along line VI-VI in FIG.
FIG. 7 is an enlarged cross-sectional view of a connecting portion between a rod cover, a head cover, and a cylinder tube.
8 is a cross-sectional view taken along line VIII-VIII in FIG.
[Explanation of symbols]
2 Outer tube 3 Inner tube 4 Bore 5 Concave groove 7 Fluid passage 7a Rod side opening of fluid passage (end in axial direction)
11 Rod cover 13 Piston 14 Head side cylinder chamber 15 Rod side cylinder chamber 21 Tube fitting groove 21a Outer tube end fitting portion 21b Inner tube end receiving portion 21c End fitting portion female screw portion 23 Threaded portion 25 Communicating passage 30, 31 Supply / exhaust port 37 Male thread portion 42 of head cover Female thread portion of outer tube

Claims (3)

A concave groove in the longitudinal direction is formed in the bore of the outer tube, and an inner tube is fitted into the bore to form a longitudinal fluid passage between the outer peripheral surface of the inner tube and the concave groove, and a piston is pivoted on the inner tube. The cylinder chamber inside the inner tube is divided into a rod side and a head side, and a pair of supply / exhaust ports is provided on either side of the tube side to close the rod side or the head side. A fluid formed by communicating the supply / discharge port and the cylinder chamber on the side not provided with the supply / discharge port via the fluid passage, and communicating the other supply / discharge port with the cylinder chamber on the side provided with the supply / discharge port. in pressure cylinder, the bore of the outer tube, the longitudinal direction of the fluid passage between the inner tube outer peripheral surface a plurality formed in the circumferential direction of the concave groove outer tube to form a plurality, in the rod cover The tube fitting groove for receiving the end portions of the outer tube and the inner tube is formed, and the tube fitting groove is formed at the end fitting portion of the outer tube and the end of the inner tube having a smaller diameter and a larger diameter than the inner tube outer diameter. The inner tube end receiving portion and the inner tube end outer periphery are fitted with a stepped shape consisting of a portion receiving portion and the rod end of the inner tube protruding from the rod side end of the outer tube toward the rod side. An annular communication path is formed by the outer tube end face, and the external threaded portion provided on the outer periphery of the rod side end of the outer tube is screwed into the internal thread provided on the outer tube end fitting portion of the rod cover. The tube and the rod cover are fixed together, and the external thread on the head end of the outer tube bore is attached to the outer periphery of the head cover The outer tube and the head cover are fixed together by screwing the external male thread, and the inner tube is sandwiched between the head cover and the rod cover from both sides in the axial direction, and the one supply / discharge port is connected to a plurality of fluids. A fluid pressure cylinder, characterized in that an axial end of the passage on the one supply / discharge port side is communicated with each fluid passage through a communication passage communicating with each other.   The fluid pressure cylinder according to claim 1, wherein the concave grooves are formed at equal angular intervals in the circumferential direction.   3. A plurality of notches for passing a pressurized fluid are formed at an end of the inner tube, and a cylinder chamber in the inner tube and a fluid passage outside the inner tube are communicated with each other through the notch. Fluid pressure cylinder.

Images