JPH09280213A - Fluid pressure cylinder having buffer mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluid pressure cylinder having a buffer mechanism excellent in durability. SOLUTION: A first end part E1 side of a rubber cushion 25 as a buffer is supported by buffer supporting grooves 23, 24 provided in a piston 9 and a cylinder cover 6 to demarcate a pressure working chamber 11. A second end part E2 side is arranged in a raised condition from the piston 9 and the cylinder cover 6. The impact of the piston 9 is buffered by deflecting the rubber cushion 25 on the whole so that the second end part E2 is brought close to the side of the piston 9 and the cylinder covers 5, 6, and the impact of the piston 9 is buffered by compressing a thick wall part 26 of the rubber cushion 25 by the pushing force received from an end face of the piston 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic cylinder with a shock absorbing mechanism.

[0002]

2. Description of the Related Art In various types of cylinders utilizing fluid pressure, it is necessary to absorb the inertia energy of a piston reaching a stroke end so as to cushion the impact exerted on the cylinder cover by the piston. Therefore, some cylinders with a shock absorbing mechanism have been proposed.

[0003] As this kind of conventional apparatus, there is one disclosed in Japanese Utility Model Laid-Open No. 3-43139, for example (see FIG. 9). In the fluid pressure cylinder 51 shown in the figure, both ends of a cylinder tube 52 are closed by a metal cylinder cover 53. In the cylinder tube 52, a metal piston 55 having a rod 54 connected to one surface is slidably accommodated. The piston 55 includes a cylinder 51
Is partitioned into two pressure action chambers. A rubber cushion 56 as a buffer is provided between the end face of the piston 55 and the inner end face of the cylinder cover 53. The rubber cushion 56 has an annular base 56 having a through hole at the center.
A lip portion 56b is provided so as to project from one end surface of a. Further, the other end surface side of the annular base portion 56 a forming the rubber cushion 56 is fixed to the end surface of the piston 55.

Therefore, when air is supplied to the pressure action chamber through the port 57, the piston 55 moves in either direction, so that the cylinder cover 53 comes into contact with the rubber cushion 56. Then, as shown in FIG. 10A, an air reservoir is formed in the cylinder 51. When the piston 55 approaches the stroke end, the lip 5
6b is elastically deformed by being pressed, and the lip portion 5
6b is pressed against the end surface of the annular base portion 56a. When the piston 55 further approaches the stroke end, FIG.
As shown in (b), the rubber cushion 56 is entirely compressed by the piston 55, and finally the piston 55 stops.

[0005] The volume of the air reservoir becomes smaller as the piston 55 approaches the stroke end. Therefore, the air in the inside gradually becomes in a compressed state, and accordingly, the drag force on the piston 55 also increases. Therefore, in the cylinder 51, in addition to the restoring force of the rubber cushion 56, a reaction force due to an increase in the pressure of the air in the air reservoir acts, thereby damping the impact of the piston 55.

[0006]

However, the annular base 5
In the cylinder 51 with a cushioning mechanism of the related art in which the lip portion 56b is provided on one side of the 6a, the lip portion 5 is structurally
It is easy for stress to concentrate at the root of 6b. Such concentration of stress causes early deterioration of the root portion of the lip portion 56b, and further causes cracks or the like in the rubber cushion 56. Therefore, the piston 5
There was a problem that the shock absorption of No. 5 could not be achieved.

Further, in the conventional cylinder 51, as can be seen from the sectional shape of the rubber cushion 56 and the state of its deformation, the compression ratio of the air in the air reservoir cannot be secured so large. For this reason, in the past, the shape of the rubber cushion 56 and the like that can obtain a higher shock absorbing capacity have been desired.

The present invention has been made in view of the above circumstances, and a first object of the present invention is to provide a hydraulic cylinder with a shock absorbing mechanism having excellent durability. A second object of the present invention is to provide a fluid pressure cylinder with a shock absorbing mechanism which has excellent durability and high shock absorbing capacity.

[0009]

In order to solve the above-mentioned problems, according to the invention as set forth in claim 1, a piston driven on the basis of supply and discharge of fluid to and from a pressure action chamber defined inside the cylinder. In the fluid pressure cylinder in which the shock of the piston is buffered by the elastic buffer disposed between the buffer and the cylinder cover, the pressure action chamber is defined on the first end side of the buffer. A member provided with the cushioning body support portion is supported by the cushioning body support portion, and the second end side thereof is arranged in a state of being floated from the member having the cushioning body support portion. After the shock of the piston is buffered by flexing the shock absorber as a whole so that the second end is close to the side, the thick portion of the shock absorber is further applied by the pressing force received from the end face of the piston. The thickness direction The cushioning mechanism with fluid pressure cylinder is characterized in that is configured to buffer the impact of the piston by compressing the gist thereof.

According to a second aspect of the present invention, in the first aspect, the shock absorber forms a fluid reservoir in the cylinder during shock absorption. According to a third aspect of the present invention, in the second aspect, the fluid reservoir is formed on one of the inner peripheral surface and the outer peripheral surface of the buffer body on which the buffer body is bent.

[0011] The invention according to claim 4 is the invention according to claims 1 to 3.
1 is a ring-shaped member having a through hole in the center and having a diameter on the first end side and a diameter on the second end side different from each other, It is assumed that the end portion side is relatively thicker than the first end portion side.

According to a fifth aspect of the present invention, in the fourth aspect, the thick portion of the cushioning body can stop the piston without contacting the end surface of the piston and the inner end surface of the cylinder cover. It has been set to the thickness of.

According to a sixth aspect of the present invention, in the fourth or fifth aspect, the first end portion of the shock absorber is loosely fitted in a shock absorber support groove provided in the cylinder cover or the piston. I was supposed to

The invention according to claim 7 is the invention according to claims 4 to 6.
In any one of the above items, the ring-shaped buffer body is provided with a strain absorbing structure for absorbing strain when it is bent.

According to an eighth aspect of the present invention, in the seventh aspect, the strain absorbing structure is a slit extending along the radial direction of the buffer body. Hereinafter, the "action" of the present invention
Will be described.

According to the first aspect of the invention, when the elastic buffer body bends, a restoring force is generated to try to eliminate the bending. Then, the restoring force due to this bending tends to push the piston back in the direction opposite to the stroke. Furthermore, when the thick portion of the shock absorber is compressed in the thickness direction by receiving the pressing force from the end face of the piston, this time the restoring force that tries to restore the compressed thick portion to its original thickness. Occurs. Then, the restoring force due to the compression tries to push the piston back in the direction opposite to the stroke. As a result, the inertial energy of the piston is absorbed, so that the shock of the piston is buffered.

Further, since the shock absorber is designed to flex as a whole when shock is absorbed, the stress generated at that time is dispersed throughout the shock absorber. Therefore, unlike the prior art, stress is not concentrated on a specific portion of the buffer body. Therefore, early deterioration due to stress concentration is prevented, and the durability of the shock absorber is surely improved.

According to the second aspect of the invention, the volume of the fluid pool formed in the cylinder at the time of shock absorbing becomes smaller as the piston approaches the stroke end. At this time, the fluid confined therein gradually becomes in a compressed state, and accordingly, the drag of the compressed fluid acting on the piston also increases. Therefore, the impact of the piston is more reliably buffered by the action of the drag in addition to the return force based on the elasticity of the buffer.

Further, in the present invention, not only the buffer body is compressed in the thickness direction, but also the buffer body is bent as a whole, so that the volume change amount of the fluid pool increases by the movement amount due to the bending. Therefore, a larger compression ratio than that of the conventional one is secured, and as a result, a high shock absorbing capacity can be obtained.

According to the invention described in claim 3, since the fluid reservoir is formed on the side where the buffer body bends, structurally,
It becomes difficult for the fluid trapped inside to escape to the outside. Therefore, the compressed state in the fluid reservoir becomes higher, and a larger drag can be obtained.

According to the fourth aspect of the present invention, since the buffer body is ring-shaped, it is easy to mount it on the buffer body support portion, and the formation of the fluid reservoir in the cylinder is facilitated. In addition, when the diameters at both ends are different,
Even when an impact is applied, the buffer can be uniformly bent without wrinkling.

According to the fifth aspect of the invention, when the thick portion is set to such a thickness, the piston stops at the stroke end without contact between the end surface of the piston and the inner end surface of the cylinder cover. To do. That is, in this case, since the elastic surface and the inelastic surface come into contact with each other,
The generated noise is smaller than that in the case where the inelastic surfaces are in contact with each other. Therefore, the sound deadening property of the cylinder is improved.

According to the sixth aspect of the present invention, the first end portion of the buffer body is loosely fitted in the buffer body support groove, so that the first end portion side is completely fixed by, for example, an adhesive or the like. Stress concentration is less likely to occur than in the case. Therefore, the durability of the buffer body is further improved. Further, since it is not necessary to fix the first end portion, the buffer body can be easily assembled.

According to the invention described in claim 7, since the strain of the cushioning body is absorbed by the presence of the strain absorbing structure, even when the cushioning body is entirely bent at the time of shock absorbing, the cushioning body has wrinkles. Less likely to occur.

According to the eighth aspect of the invention, when the slit extending in the radial direction is formed in the buffer body, not only the strain of the buffer body is absorbed in that portion, but also a small amount from the fluid reservoir. The fluid can be leaked. As a result, the sound deadening property of the cylinder can be improved as compared with the case where the fluid reservoir is completely sealed.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A hydraulic cylinder 1 with a shock absorbing mechanism according to an embodiment of the present invention will be described below in detail with reference to FIGS.

As shown in FIG. 1, the cylinder tube 2 constituting the cylinder 1 of the present embodiment is a cylindrical metal member having a first port 3 and a second port 4. Of the openings in the cylinder tube 2, the opening on the right side in FIG. 1 is closed by a metal head cover 5 as a cylinder cover. 1 is closed by a metal rod cover 6 as a cylinder cover. The head cover 5 is directly fitted to the inner wall surface of the cylinder tube 2. On the other hand, the rod cover 6 is fixed to the inner wall surface of the cylinder tube 2 by a C-ring 7.

A metal piston 9 having a metal rod 8 on one end face is slidably accommodated in an internal space formed in the cylinder tube 2. And
The presence of the piston 9 divides the internal space into two pressure action chambers 10 and 11. More specifically, the head-side pressure action chamber 10 is defined by the inner end surface of the head cover 5, the inner peripheral surface of the cylinder tube 2, and the right end surface of the piston 9, that is, a plurality of members. The first port 3 communicates with the pressure action chamber 10. The rod-side pressure action chamber 11 is defined by the inner end surface of the rod cover 6, the inner peripheral surface of the cylinder tube 2, the left end surface of the piston 9, and the peripheral surface of the rod 8, that is, a plurality of members. The second port 4 communicates with the pressure action chamber 11.

One end of the rod 8 connected to the piston 9 projects to the outside of the cylinder tube 2 through a rod insertion hole 12 penetrating the center of the rod cover 6. A rod 8 is provided on the inner wall surface of the rod insertion hole 12.
In order to reduce the sliding resistance of the bearing, a region serving as the bearing surface 13 is provided. Further, a packing mounting concave portion is provided in a region outside the region serving as the bearing surface 13, and an annular rod packing 14 is mounted therein. The rod packing 14 seals the peripheral surface of the rod 8 and the inner wall surface of the rod insertion hole 12. A piston packing 15 and a wear ring 16 as seal members are also mounted on the peripheral surface of the piston 9 that slides on the inner peripheral surface of the cylinder tube 2.

As shown in FIGS. 1 and 3, there is a step D1 on the inner end surface of the rod cover 6 so that the central portion of the rod cover 6 is retracted more than the peripheral portion thereof. Similarly, there is a step D1 on the right end face of the piston 9 so that the center portion is retracted more than the peripheral portion. Further, a buffer body support groove 23 as a buffer body support portion is formed in a portion having a step D1 on the inner end surface of the rod cover 6. The buffer body support groove 23 has an annular shape and opens toward the central axis direction of the cylinder tube 2. A buffer body support groove 24 as a buffer body support portion is formed at a portion having a step D1 on the right end surface of the piston 9. The buffer support groove 24 is also annular and opens in the direction of the central axis of the cylinder tube 2. Then, a rubber cushion 25 as a buffer having elasticity is attached to the support grooves 23 and 24.

Next, the shape and the like of the rubber cushion 25 used in this embodiment will be described. The rubber cushion 25 used in the present embodiment is made of urethane rubber and has suitable elasticity as a cushion. In addition to urethane rubber, for example, NBR, HNBR,
It is possible to select rubber such as fluororubber.

As shown in FIG. 2, the rubber cushion 25 is a ring-shaped member having a through hole at the center,
The diameter of the first end E1 is different from the diameter of the second end E2. The first end E1 is the support groove 23, 2
4 and the second end E2
Is the end on the side not supported by the support grooves 23, 24. In the case of this rubber cushion 25, the first end E1
The diameter on the side is larger than the diameter on the second end E2 side.

As shown in FIGS. 2 and 3 (a), this rubber cushion 25 does not have a lip portion or the like anywhere. Therefore, it has a simple sectional shape as compared with a rubber cushion provided with such a thing. When the rubber cushion 25 is cut, a pair of straight and parallel line segments is formed on the cut surface. The surface to which the line segment on the non-through-hole side belongs is defined by the outer peripheral surface 25b.
And the surface to which the one on the through-hole side belongs is defined as the inner peripheral surface 25.
a. Further, in this rubber cushion 25, the first end E1 side is a relatively thin wall portion, and the second end E2 side is a relatively thick wall portion 26. In the present embodiment, the thickness of the thick portion 26 is about twice the thickness of the thin portion. At least the thick portion 26 has a uniform thickness. This is because the pressing force of the piston 9 acts evenly on the rubber cushion 25 with such a configuration.

In the present embodiment, the rubber cushion 2
The first end E1 side of 5 is loosely fitted in the support grooves 23 and 24. That is, the first end E1 side of the rubber cushion 25 is fitted into the support grooves 23 and 24 without using any kind of adhesive or the like.

When the rubber cushion 25 is attached to the support groove 23 in the pressure working chamber 11 on the rod side, the support groove 2
One side wall of 3 and the knife-edge-like surface at the first end E1 are in surface contact. At this time, the second end side E2 is
The rod cover 6 which is a member provided with the support groove 23 is lifted from the inner end surface. In other words, the second
The end side E2 of the is in a state of protruding toward the piston 9 which is a member arranged so as to face the rod cover 6.

When the rubber cushion 25 is attached to the support groove 24 in the pressure acting chamber 10 on the head side,
One side wall of the support groove 24 and the knife edge-shaped surface are in surface contact with each other. At this time, the second end side E2 is connected to the support groove 24
The piston 9 which is a member provided with is lifted up from the left end surface. In other words, the second end side E2
Is in a state of protruding toward the inner end surface of the head cover 5 which is a member arranged so as to face the piston 9.

When no or almost no stress is applied as shown in FIG. 3A, the line segments belonging to the inner peripheral surface 25a and the outer peripheral surface 25b are both about 30 with the central axis of the rubber cushion 25 as a reference. It is in a state of being inclined by about °. Also, both are linear and parallel. FIG.
When stress is applied as shown in (b), the line segments belonging to the inner peripheral surface 25a and the outer peripheral surface 25b both become arcuate curves.
That is, at this time, the rubber cushion 25 has the inner peripheral surface 25a.
It is in a state of being totally bent in the direction of.

The maximum thickness of the air cushion 25 (that is, the inner peripheral surface 25a and the outer peripheral surface 25b of the thick portion 26).
Distance) is set to a value slightly larger than the size of the step D1. Therefore, the rubber cushion 25 is adapted to be compressed in the thickness direction by the inertia energy of the piston 9 during shock absorption. Further, when the rubber cushion 25 is compressed, the piston 9 is stopped without bringing the end surface of the piston 9 and the inner end surface of the rod cover 6 into contact with each other.

Next, the operation of the fluid pressure cylinder 1 thus constructed and the operation of the rubber cushion 25 will be described. Hereinafter, only the rubber cushion 25 on the rod side shown in FIGS. 3A and 3B will be referred to. That is, since there is no fundamental difference in the operation of the rubber cushion 25 between the rod side and the head side, a detailed description of the latter will be omitted.

A piston 9 is provided at the stroke end on the head side.
When air is supplied to the first port 3 in a certain state, air is introduced into the pressure action chamber 10 on the head side, and
The pressure inside rises. Then, the piston 9 and the rod 8
Moves in the direction of the rod side (that is, the left side in FIG. 1), and the air in the pressure action chamber 11 on the rod side is discharged to the outside via the second port 4.

FIG. 3A shows a state in which the piston 9 reaches the vicinity of the stroke end and the second end E2 of the rubber cushion 25 contacts the left end surface of the piston 9. At this time, the rubber cushion 25 partitions the inside of the pressure acting chamber 11 on the rod side into two spaces. One of them is a space defined on the outer peripheral surface 25b side of the rubber cushion 25, and the space communicates with the second port 4 side. The remaining one is a space defined on the inner peripheral surface 25a side of the rubber cushion 25, and the space is not in communication with the second port 4 side. The latter space is specifically defined by the inner peripheral surface 25a of the rubber cushion 25, the left side surface of the piston 9, the inner end surface of the rod cover 6, and the peripheral surface of the rod 8, in which air is sealed. It has become.
Hereinafter, the latter space is referred to as an air reservoir S1.

When the piston 9 in the state of FIG. 3 (a) further approaches the stroke end, the rubber cushion 25, which receives the pressing force from the piston 9, is elastically deformed. That is, the rubber cushion 25 has the second end E on the side of the rod cover 6 which is a member provided with the buffer support groove 23.
It flexes as a whole so that two come close to each other. Further, since the rubber cushion 25 is an elastic body, the rubber cushion 25 has a restoring force that cancels the bending of the rubber cushion 25. Then, the restoring force caused by this bending tries to push the piston 9 back in the direction opposite to the stroke. Therefore, the inertial energy of the piston 9 is absorbed, so that the shock is buffered. When the rubber cushion 25 is bent, the rubber cushion 25 is deformed with the corner portion P1 of the knife edge-shaped surface and the inner peripheral surface 25a as a fulcrum. Then, the sealing surface pressure between the rubber cushion 25 and the inner end surface of the rod cover 6 increases, and the sealing stability between them increases.

As the piston 9 further approaches the stroke end, the flexure of the rubber cushion 25 increases,
The inner peripheral surface 25a comes into close contact with the inner end surface of the rod cover 6. Then, when the pressing force is applied from the left end surface of the piston 9, the thick portion 26 of the rubber cushion 25 is compressed in the thickness direction. At this time, instead of the restoring force due to the flexure, a restoring force that tries to restore the compressed thick portion 26 to the original thickness is generated in the rubber cushion 25. And the restoring force due to the compression is
Attempts to push the piston 9 back in the opposite direction of the stroke. Therefore, the inertial energy of the piston 9 is absorbed,
Thus, shock is buffered.

Further, the piston 9 has a structure shown in FIGS.
When the state changes to (b), the volume of the air reservoir S1 decreases as the piston 9 moves. At this time,
The air trapped inside is gradually compressed, and the drag force of the air on the piston 9 increases accordingly. Therefore, in addition to the restoring force caused by the bending and compression of the rubber cushion 25, the drag force of the air also acts. This also damps the impact of the piston 9.

FIG. 3B shows a state in which the piston 9 reaches the stroke end. The piston 9
Stops after not being in contact with the inner end surface of the rod cover 6 after sufficient shock absorption is achieved as described above. As a result, the position of the stroke end at the left end is determined.

During a stroke in the opposite direction, the piston 9 stops without contacting the inner end surface of the head cover 5 after the rubber cushion 25 has sufficiently cushioned the shock. As a result, the position of the stroke end at the right end is determined.

In the following, the characteristic effects of this embodiment will be listed. (A) The rubber cushion 25 used as a cushioning member in the cylinder 1 is shaped and arranged so as to be flexed as a whole when shock absorbing. Therefore, the stress generated when it bends is dispersed throughout the rubber cushion 25. Therefore, unlike the conventional product in which the lip portion is projectingly provided on the annular base portion, stress is not concentrated on a specific portion of the rubber cushion 25. Note that, even when the material is compressed in the thickness direction, stress concentration on a specific portion does not occur similarly. Therefore, early deterioration due to stress concentration can be prevented, and the durability of the rubber cushion 25 can be reliably improved. Therefore, it is possible to realize an excellent fluid pressure cylinder 1 capable of absorbing shock over a long period of time.

(B) In this embodiment, the rubber cushion 25, which is an elastic body as described above, has a restoring force that attempts to eliminate the bending of itself and the compressed thick portion 26. There is a restoring force that tries to restore the thickness of the. Then, the restoring force due to the bending / compression is applied to the piston 9
Try to push back in the opposite direction of the stroke. As a result, the inertial energy of the piston 9 is absorbed, and the impact of the piston 9 is buffered.

(C) The cylinder 1 of the present embodiment is characterized in that the air cushion S1 as a fluid reservoir is formed in the cylinder tube 2 by the rubber cushion 25 or the like when the shock is absorbed. Therefore, in addition to the restoring force based on the elastic force of the rubber cushion 25, a drag force acts on the piston 9 generated by the compression of the air in the air reservoir S1. Therefore, the shock of the piston 9 can be more reliably buffered. That is, the formation of the air pool S1 contributes to the improvement of the shock absorbing ability.

Further, in the case of this rubber cushion 25, not only the thick portion 26 is compressed in the thickness direction, but also the entire thick portion 26 is bent. Therefore, the amount of change in volume of the air reservoir S1 increases by the amount of movement due to the bending. Therefore, a large compression ratio is secured as compared with the conventional one, and as a result, a high shock absorbing capacity can be obtained (Figs. 3 (a) and (b)).
reference).

(D) In this cylinder 1, the air reservoir S
1 is characterized in that the rubber cushion 25 is formed on the inner peripheral surface 25a side, which is the side on which the rubber cushion 25 bends. In this case, it is difficult for the air trapped in the air reservoir S1 to escape to the outside due to its structure. Therefore, the compressed state of the internal air becomes higher, and a greater drag can be obtained. This also contributes to the improvement of the shock absorbing capacity.

(E) In the cylinder 1 of this embodiment, since the rubber cushion 25 is ring-shaped, the cushion support groove 2 is formed.
It is easy to mount on the cylinders 3 and 24, and the formation of the compartment of the air reservoir S1 in the cylinder tube 2 is also facilitated.
Also, if the diameters at both ends E1 and E2 are different,
Even when an impact is applied, the rubber cushion 25 can be uniformly bent without wrinkling.

(F) In the cylinder 1 of the present embodiment, the first end E1 of the rubber cushion 25 is attached to the buffer support groove 23,
24. Therefore, stress concentration is less likely to occur on the rubber cushion 25 than when the first end portion E1 is completely fixed by, for example, an adhesive. And this contributes to the improvement of the durability of the rubber cushion 25. Further, since the fixing of the first end E1 becomes unnecessary, the assembly of the rubber cushion 25 is facilitated.

(G) Since this rubber cushion 25 has a relatively simple cross-sectional shape as shown in FIG. 2 and the like, it has the advantage of being less difficult to manufacture than conventional products. That is, even when the mold is formed, the shape of the inner surface of the mold is simple, and the mold can be easily removed.

(H) In this cylinder 1, even when the piston 9 is stopped at the stroke end, the end face of the piston 9 contacts the inner end face of the head cover 5, and the end face of the piston 9 and the rod cover 6 No contact with the end face occurs. In this case, the urethane surface, which is an elastic surface, and the metal surface, which is an inelastic surface, come into contact with each other.
Therefore, the noise generated by the contact is surely reduced as compared with the conventional device in which the non-elastic surfaces (that is, the metal surfaces) contact each other. Therefore, it is possible to provide the cylinder 1 having excellent sound deadening properties.

(I) As an improved example of the present embodiment, for example, by providing an orifice in the rod cover 6, a gap between the air reservoir S1 formed on the inner peripheral surface 25a side and a non-sealed area formed on the outer peripheral surface 25b side is provided. You may communicate. By doing so, the shock absorbing ability can be controlled by appropriately setting the degree of restriction of the orifice.

The present invention can be modified, for example, as follows. (1) Fluid pressure cylinder 3 of another example 1 shown in FIGS. 4 to 6.
1, the rubber cushion 32 having a slightly different structure from that of the above-described embodiment is used. This rubber cushion 32
Has a thick portion 33 and is formed such that the diameter on the first end E1 side is smaller than the diameter on the second end E2 side. Therefore, when the piston 9 comes into contact with the rubber cushion 32, the rubber cushion 32 is entirely bent toward the outer peripheral surface 32b side rather than the inner peripheral surface 32a side. Also,
At this time, an air reservoir S1 is formed on the outer peripheral surface 32a side. The buffer body support groove 2 in the cylinder 31
The installation position of 3 is slightly closer to the center than in the above-described embodiment. With the cylinder 31 having the above-described structure, it is possible to obtain the same effects as those of the above embodiment. In addition, in the cylinder 31, since the air reservoir S1 is formed on the inner peripheral surface 32a side, the compressed state of air is not so high as in the above-described embodiment.
For this reason, the shock absorbing ability is the same as that of the embodiment, while the sound deadening is more excellent than that.

(2) The fluid pressure cylinder 41 of another example 2 shown in FIG. 7 may be constructed. In the cylinder 41, the head cover 43 that closes the right end of the cylinder tube 42 is provided with the first port 3. Further, the rod cover 44 that closes the left end of the cylinder tube 42 is provided with the second port 4. Unlike the above-described embodiment and the first modified example, in this cylinder 41, two rubber cushions 32 as cushioning bodies are used for both the cover 4 and the cover 4.
It is loosely fitted in the buffer body support groove 23 formed on the side of 3,4. In addition, the first port 3 is the head side pressure action chamber 1.
Connect to the area that does not become the air reservoir S1 at 0,
The second port 4 communicates with a region of the pressure acting chamber 11 on the rod side that does not serve as an air reservoir S1. Even with the above-described configuration, it is possible to obtain the same effects as the above-described embodiment.

(3) A rubber cushion 46 of another example 3 shown in FIG. 8 has a construction in which slits 48 and 49 as strain absorbing structures are formed in the rubber cushion 25 described above. That is, the rubber cushion 46 has a thick portion 47, and the diameter on the first end E1 side is the second end E2.
Is larger than the diameter. Four inner slits 48 are formed on the inner peripheral surface 46a side, and four outer slits 49 are similarly formed on the outer peripheral surface 46b side. These slits 48 and 49 are both rubber cushions 4.
6 along the radial direction.

Therefore, according to the rubber cushion 46, the strains are absorbed by the slits 48 and 49, so that wrinkles are less likely to occur even when the entire cushion is flexed during shock absorption. Further, with this structure, a small amount of air can be leaked from the air reservoir S1. Therefore,
The sound deadening property of the cylinder 1 is improved as compared with the case where the air reservoir S1 is completely sealed. In addition, this kind of slit 4
8, 49 may be formed on one of the inner peripheral surface 46a and the outer peripheral surface 46b.

(4) The buffer body supporting grooves 23 and 24 as the buffer body supporting portions are both covers 5 and 6 as in the second modification.
It is not limited to be provided on the side, or one on the sides of the covers 5 and 6 and the other on the side of the piston 9 as in the embodiment and the other example 1. For example, both 23 and 24 may be provided on the piston 9 side.

(5) A member other than the covers 5 and 6 and the piston 9 for partitioning the pressure action chambers 10 and 11, for example, the rod 8 and the cylinder tube 2, and buffers such as the buffer support grooves 23 and 24. Providing a body support is also acceptable. However, the configuration in which these are provided on the covers 5, 6 and the piston 9 as in the embodiment and the like is advantageous in that the assembly and the like are easy.

(6) The elastic buffer body may be formed by using a synthetic resin other than rubber. Here, in addition to the technical ideas described in the claims, technical ideas grasped by the above-described embodiments are listed below together with their effects.

(1) In any one of claims 2 to 8, the cylinder cover is provided with an orifice for communicating between a fluid reservoir region and a fluid reservoir region in the pressure action chamber formed in the cylinder. A fluid pressure cylinder with a shock absorber. With this configuration, the shock absorbing ability can be controlled.

(2) A through hole is formed in the center, and the diameter on the first end side is different from the diameter on the second end side, and the second end side is the first side. A rubber cushion for a fluid pressure cylinder with a buffer mechanism that is formed to be relatively thicker than the end side of the. By using the rubber cushion having this structure, the cylinder of the present invention can be reliably realized.

(3) In the technical concept 2, a rubber cushion in which at least the thick portion has a uniform thickness. If the rubber cushion having this structure is used, the pressing force of the piston can be made to act evenly.

(4) In the technical ideas 2 and 3, a rubber cushion having a strain absorbing structure for absorbing strain when it is bent. By using the rubber cushion having this structure, it is possible to prevent wrinkles from being generated during shock absorption.

(5) In the technical idea 4, the strain absorbing structure is a rubber cushion which is a plurality of slits extending in the radial direction. By using the rubber cushion having this structure, it is possible to prevent wrinkles from occurring and improve the sound deadening property.

The technical terms used in this specification are defined as follows. "Fluid: Nitrogen supplied and exhausted to drive the cylinder,
Oxygen, carbon dioxide, argon, hydrogen, a gas such as air as a mixture thereof, and other substances having properties similar to these. "

[0070]

As described in detail above, according to the invention described in claims 1 to 8, it is possible to provide a fluid pressure cylinder with a shock absorbing mechanism which is excellent in durability.

According to the second aspect of the present invention, as a result of the formation of the fluid pool, a drag force acts on the piston in addition to the restoring force based on the elasticity of the shock absorber. Therefore, it is possible to provide a cylinder having a high shock absorbing capacity and excellent durability.

According to the third aspect of the present invention, since the compressed state of the fluid in the fluid reservoir becomes higher, the shock absorbing ability can be further improved. According to the invention as set forth in claim 4, the mounting of the cushioning body is simplified, the formation of the compartment for the fluid reservoir is facilitated, and the cushioning body can be uniformly bent.

According to the fifth aspect of the invention, as a result of the piston stopping due to the contact between the elastic surface and the inelastic surface, the sound deadening of the cylinder can be improved. According to the invention described in claim 6, it is possible to improve the durability of the shock absorber and facilitate the assembling of the shock absorber.

According to the invention described in claim 7, wrinkles are prevented by absorbing the strain of the buffer body. According to the invention described in claim 8, it is possible to prevent the generation of wrinkles and improve the sound deadening property of the cylinder.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view of a fluid pressure cylinder with a shock absorber according to an embodiment.

2A is a plan view of a rubber cushion used in the fluid pressure cylinder, FIG. 2B is a bottom view thereof, and FIG. 2C is a sectional view thereof.

3A and 3B are enlarged cross-sectional views of a main part for explaining the action of the rubber cushion.

FIG. 4 is a partial cross-sectional view showing a fluid pressure cylinder with a cushioning mechanism of another example 1.

5A is a plan view of a rubber cushion used in the fluid pressure cylinder, FIG. 5B is a bottom view thereof, and FIG. 5C is a sectional view thereof.

6 (a) and 6 (b) are enlarged cross-sectional views of main parts for explaining the action of the rubber cushion.

FIG. 7 is a partial cross-sectional view showing a fluid pressure cylinder with a cushioning mechanism of another example 2.

FIG. 8A is a plan view of a rubber cushion according to another example 3,
(B) is a bottom view thereof, and (c) is a sectional view thereof.

FIG. 9 is a partial cross-sectional view showing a conventional fluid pressure cylinder with a cushioning mechanism.

10A and 10B are enlarged cross-sectional views of a main part for explaining the action of the rubber cushion in the conventional example.

[Explanation of symbols]

1, 31, 41 ... Fluid pressure cylinder with buffer mechanism, 5, 4
3 ... Head cover as cylinder cover, 6, 44 ...
Rod cover as cylinder cover, 9 ... piston,
10, 11 ... Pressure action chamber, 23, 24 ... Buffer support groove as buffer support, 25, 32, 46 ... Rubber cushion as buffer, 25a, 32a, 46a ... Inner peripheral surface,
25b, 32b, 46b ... Outer peripheral surface, 26, 33, 47 ...
Thick parts, 48, 49 ... Slits as strain absorbing structure, S1 ... Air pool as fluid pool, E1 ... 1st
End, E2 ... second end.

Claims (8)

[Claims] An elastic cushioning member disposed between a piston driven based on supply and discharge of a fluid into and from a pressure working chamber defined inside a cylinder and a cylinder cover.
In a fluid pressure cylinder that buffers the impact of the piston, a first end portion side of the shock absorber is supported by a shock absorber support portion provided in a member that defines the pressure action chamber, and a second end thereof is supported. The end portion side of the buffer body is arranged so as to be floated from the member provided with the buffer body support portion, and the buffer body is arranged so that the second end portion is close to the member side provided with the buffer body support portion. After the shock of the piston is buffered by bending it as a whole, the shock of the piston is buffered by further compressing the thick portion of the buffer body in the thickness direction by the pressing force received from the end face of the piston. A fluid pressure cylinder with a shock absorbing mechanism characterized by being configured as follows. 2. The fluid pressure cylinder with a cushioning mechanism according to claim 1, wherein the cushioning body forms a fluid pool in the cylinder during shock absorbing. 3. The fluid pressure with a buffer mechanism according to claim 2, wherein the fluid reservoir is formed on one of the inner peripheral surface and the outer peripheral surface of the buffer body on which the buffer body flexes. Cylinder. 4. The buffer body is a ring-shaped member having a through hole at the center and having a diameter on the first end side and a diameter on the second end side different from each other, and the second end section. The fluid pressure cylinder with a cushioning mechanism according to any one of claims 1 to 3, wherein the side is relatively thicker than the first end side. 5. The thick portion of the cushioning body is set to a thickness such that the piston can be stopped without abutting the end surface of the piston and the inner end surface of the cylinder cover. The fluid pressure cylinder with a shock absorbing mechanism according to claim 4. 6. The buffer body according to claim 4, wherein the first end portion of the buffer body is loosely fitted in a buffer body supporting groove provided in the cylinder cover or the piston.
The fluid pressure cylinder with a buffer mechanism according to 1. 7. The ring-shaped buffer body is provided with a strain absorbing structure for absorbing strain when it is bent, according to any one of claims 4 to 6. A fluid pressure cylinder with a buffer mechanism described. 8. The fluid pressure cylinder with a shock absorbing mechanism according to claim 7, wherein the strain absorbing structure is a slit extending along a radial direction of the shock absorbing body.