JP6889137B2 - Fluid pressure cylinder - Google Patents

Description

The present invention relates to a fluid pressure cylinder.

Conventionally, in a fluid pressure cylinder, when the piston reciprocally housed in the cylinder tube reaches the stroke end, the shock from the piston is absorbed and the piston is stopped as a buffer at the stroke end. Those provided with members are known, for example, in Patent Document 1. In the fluid pressure cylinder of Patent Document 1, a cushioning member made of an elastic material such as rubber is provided at a position facing the piston on the inner end surface of the rod cover and at the end surface of the piston facing the head cover.

Then, when the piston reaches the stroke end on the rod cover side, the piston comes into contact with the cushioning member provided on the inner end surface of the rod cover. As a result, the cushioning member is crushed and the strain energy of the cushioning member increases, so that the impact force applied to the piston or the rod cover is absorbed by the cushioning member, and the piston stops bufferingly at the stroke end on the rod cover side. .. On the other hand, when the piston reaches the stroke end on the head cover side, the cushioning member provided on the end face of the piston comes into contact with the head cover. As a result, the cushioning member is crushed and the strain energy of the cushioning member is increased, so that the impact force applied to the piston or the head cover is absorbed by the cushioning member, and the piston is stopped as a buffer at the stroke end on the head cover side.

Japanese Unexamined Patent Publication No. 2005-320994

As shown in FIG. 11A, if the physique of the cylinder tube 101 is reduced in order to reduce the size of the fluid pressure cylinder 100, the outer diameter of the piston 102 housed in the cylinder tube 101 becomes smaller. Therefore, in order to increase the strain energy of the cushioning member 103 provided on the end surface 102a of the piston 102, it is necessary to increase the contact area between the cushioning member 103 and the head cover 104, so that the shape of the cushioning member 103 is omitted. It has a disk shape. Then, the outer diameter of the cushioning member 103 increases with respect to the thickness of the cushioning member 103, making it difficult for the cushioning member 103 to be elastically deformed. Therefore, since the drag force acting on the head cover 104 from the cushioning member 103 increases, a large impact force is applied to the piston 102 or the head cover 104, and the piston 102 or the head cover 104 may be damaged. Further, as the piston 102 becomes smaller, the operating speed of the piston 102 becomes faster. At this time, if the cushioning member 103 is difficult to be elastically deformed and the drag force acting on the head cover 104 from the cushioning member 103 is increased, the impact force applied to the piston 102 becomes larger than the size of the piston 102. There is also the problem that it is easy.

A housing recess 105 is formed in the end surface 102a of the piston 102. A locking claw 105a protruding inward of the accommodating recess 105 is formed on the inner peripheral surface of the accommodating recess 105. The cushioning member 103 has a flange 103a that can be locked to the locking claw 105a, and a deformed portion 103b that is continuous with the flange 103a and projects outward from the accommodating recess 105 via the inside of the locking claw 105a. There is. Then, by inserting the cushioning member 103 into the accommodating recess 105 so that the flange 103a is locked by the locking claw 105a, the cushioning member 103 is supported in a state of being fitted into the accommodating recess 105.

As shown in FIG. 11B, when the deformed portion 103b of the cushioning member 103 abuts on the head cover 104 and is crushed, the deformed portion 103b is elastically deformed so as to bulge toward the locking claw 105a. , The outer surface 103c of the deformed portion 103b comes into contact with the locking claw 105a. Then, the elastic deformation of the deformed portion 103b becomes more difficult to be performed, and the drag force acting on the head cover 104 from the cushioning member 103 sharply increases. As a result, a large impact force is applied to the piston 102 or the head cover 104, and the piston 102 or the head cover 104 may be damaged.

The present invention has been made to solve the above problems, and an object of the present invention is to suppress the drag force acting on the head cover from the cushioning member and stably absorb the impact force applied to the piston or the head cover by the cushioning member. The purpose is to provide a fluid pressure cylinder that can be used.

The fluid pressure cylinder that solves the above problems includes a cylinder tube, a head cover attached to one end of the cylinder tube, a piston that is reciprocally housed in the cylinder tube, and an end surface of the piston that faces the head cover. A cushioning member made of an elastic material provided in the above, a housing recess is formed on the end surface of the piston, and a locking claw projecting inside the housing recess is provided on the inner peripheral surface of the housing recess. The cushioning member is provided with a flange that can be locked to the locking claw, and a deformed portion that is continuous with the flange and projects outward from the accommodating recess via the inside of the locking claw. The shock absorbing member absorbs the impact force applied to the piston or the head cover by elastically deforming the deformed portion so as to abut and crush the head cover and bulge toward the locking claw. In the fluid pressure cylinder, the deformed portion is crushed and locked at at least one of the portion of the deformed portion facing the locking claw and the portion of the locking claw facing the deformed portion. A relief portion is provided to prevent the deformed portion from coming into contact with the locking claw when elastically deformed so as to bulge toward the claw.

In the fluid pressure cylinder, the relief portion has a shape that ensures a non-contact state between the deformed portion and the locking claw even when the maximum strain energy is applied to the cushioning member, and the relief portion in the deformed portion. The amount of protrusion from the flange may be set to an amount that ensures a non-contact state between the end face of the piston and the head cover even when the maximum strain energy is applied to the cushioning member.

In the fluid pressure cylinder, even if the deformed portion is elastically deformed and the end face of the piston comes into contact with the head cover, the relief portion ensures a non-contact state between the deformed portion and the locking claw. It should be in shape.

In the fluid pressure cylinder, the relief portion may be provided at a portion of the deformed portion facing the locking claw.
In the fluid pressure cylinder, the relief portion may be a tapered portion that inclines so as to separate from the locking claw as it separates from the flange.

In the fluid pressure cylinder, the cushioning member may further have an accommodating recess side relief portion for suppressing contact with the inner peripheral surface of the accommodating recess when the cushioning member is elastically deformed.

According to the present invention, the drag force acting on the head cover from the cushioning member can be suppressed, and the impact force applied to the piston or the head cover can be stably absorbed by the cushioning member.

FIG. 5 is a cross-sectional view showing a fluid pressure cylinder in the embodiment. An enlarged cross-sectional view showing a piston and a cushioning member. Perspective view of the cushioning member. An enlarged cross-sectional view showing a state in which the cushioning member is in contact with the head cover. An enlarged cross-sectional view showing a state in which the cushioning member is elastically deformed. The graph which shows the relationship between the drag force acting on the head cover from a cushioning member and the amount of deformation of a cushioning member. The graph which shows the relationship between the drag force acting on the head cover from a cushioning member, and the strain energy of a cushioning member. An enlarged cross-sectional view showing a piston and a cushioning member in another embodiment. The perspective view of the cushioning member in another embodiment. The perspective view of the cushioning member in another embodiment. (A) is a cross-sectional view showing a part of the fluid pressure cylinder in the conventional example, and (b) is an enlarged cross-sectional view showing a state in which the cushioning member is elastically deformed.

Hereinafter, an embodiment in which the fluid pressure cylinder is embodied will be described with reference to FIGS. 1 to 7.
As shown in FIG. 1, the fluid pressure cylinder 10 is attached to a cylindrical cylinder tube 11, a head cover 12 attached to one end of the cylinder tube 11 in the axial direction, and the other end of the cylinder tube 11 in the axial direction. It includes a rod cover 13. The head cover 12 closes the opening on one end side of the cylinder tube 11. The rod cover 13 closes the opening on the other end side of the cylinder tube 11. The cylinder chamber 14 is partitioned in the cylinder tube 11 by the cylinder tube 11, the head cover 12, and the rod cover 13. The inner peripheral surface of the cylinder tube 11 forming the cylinder chamber 14 is cylindrical.

A first fluid supply / discharge port 11a that opens to the inner peripheral surface of the cylinder tube 11 is formed near the head cover 12 on the outer peripheral wall of the cylinder tube 11. A second fluid supply / discharge port 11b that opens to the inner peripheral surface of the cylinder tube 11 is formed near the rod cover 13 on the outer peripheral wall of the cylinder tube 11.

The cylinder chamber 14 houses an annular piston 15 that can reciprocate in the cylinder chamber 14. Therefore, the piston 15 is housed in the cylinder tube 11 so as to be reciprocating. The piston 15 divides the cylinder chamber 14 into a first pressure acting chamber 14a on the head cover 12 side and a second pressure acting chamber 14b on the rod cover 13 side. The first pressure action chamber 14a communicates with the first fluid supply / discharge port 11a, and the second pressure action chamber 14b communicates with the second fluid supply / discharge port 11b.

A rubber piston packing 15s that seals between the first pressure action chamber 14a and the second pressure action chamber 14b is mounted on the outer peripheral surface of the piston 15. Further, a magnet 16 for detecting the piston position is mounted closer to the rod cover 13 than the piston packing 15s on the outer peripheral surface of the piston 15. Further, an incomplete annular wear ring 17 having a slit is mounted closer to the head cover 12 than the piston packing 15s on the outer peripheral surface of the piston 15. The outer peripheral surface of the wear ring 17 is located radially outside the piston 15 with respect to the outer peripheral surface of the piston 15. The outer peripheral surface of the wear ring 17 is in sliding contact with the inner peripheral surface of the cylinder tube 11, so that the piston 15 is prevented from being eccentric.

A piston rod 18 is attached to the piston 15. The end of the piston rod 18 opposite to the piston 15 projects outward through the rod insertion hole 13h formed in the rod cover 13. The piston 15 and the piston rod 18 move integrally along the axial direction of the cylinder tube 11. Therefore, the piston rod 18 can appear and disappear with respect to the cylinder tube 11.

An annular cushioning member 19 is provided on the end surface 15a of the piston 15 on the rod cover 13 side. The cushioning member 19 is made of rubber, which is an elastic material. The cushioning member 19 is positioned in a state where the end face on the piston 15 side is in contact with the end face 15a of the piston 15 by being press-fitted into the piston rod 18. Further, an annular cushioning member 20 is provided on the end surface 15b of the piston 15 on the head cover 12 side. Therefore, the fluid pressure cylinder 10 includes a cushioning member 20 made of an elastic material provided on the end surface 15b of the piston 15 facing the head cover 12. The cushioning member 20 is made of rubber.

As shown in FIG. 2, a circular hole-shaped accommodating recess 30 is formed in the end surface 15b of the piston 15. An annular locking claw 31 is provided at the open end of the accommodating recess 30 so as to project inward of the accommodating recess 30 from the open end of the accommodating recess 30.

As shown in FIG. 3, the cushioning member 20 is continuous with the annular flange 21 that can be locked to the locking claw 31 and protrudes outward from the accommodating recess 30 via the inside of the locking claw 31. It has a disk-shaped deformed portion 22 and a disk-shaped deformed portion 22. As shown in FIG. 2, the portion of the deformed portion 22 facing the locking claw 31 is a tapered portion 23 that is inclined so as to be separated from the locking claw 31 as it is separated from the flange 21. Therefore, the outer diameter of the deformed portion 22 gradually decreases as the distance from the flange 21 increases. The end surface 22e of the deformed portion 22 continuous with the edge of the tapered portion 23 opposite to the flange 21 has a flat surface shape.

Then, by inserting the cushioning member 20 into the accommodating recess 30 so that the flange 21 is locked by the locking claw 31, the cushioning member 20 is supported in a state of being fitted into the accommodating recess 30. In the state before the cushioning member 20 is elastically deformed, the outer peripheral surface 21a of the flange 21 and the inner peripheral surface 30a of the accommodating recess 30 are in a non-contact state.

Next, the operation of this embodiment will be described.
As shown in FIG. 1, when the fluid is supplied from the first fluid supply / discharge port 11a to the first pressure action chamber 14a, the piston 15 starts to move toward the rod cover 13. Then, the fluid in the second pressure action chamber 14b is discharged to the outside through the second fluid supply / discharge port 11b, and the piston 15 moves until it reaches the stroke end on the rod cover 13 side. As a result, the piston rod 18 moves in the direction of projecting with respect to the cylinder tube 11. When the piston 15 reaches the stroke end on the rod cover 13 side, the cushioning member 19 comes into contact with the rod cover 13. As a result, the cushioning member 19 is crushed and elastically deformed so as to bulge toward the inner peripheral surface of the cylinder tube 11, and the strain energy of the cushioning member 19 increases, so that the impact applied to the piston 15 or the rod cover 13 is applied. The force is absorbed by the cushioning member 19, and the piston 15 is buffered and stopped at the stroke end on the rod cover 13 side.

The cushioning member 19 is being crushed and elastically deformed so as to bulge toward the inner peripheral surface of the cylinder tube 11 so that the outer peripheral surface of the cushioning member 19 does not come into contact with the inner peripheral surface of the cylinder tube 11. The clearance between the outer peripheral surface of the cushioning member 19 and the inner peripheral surface of the cylinder tube 11 is preset.

When the fluid is supplied from the second fluid supply / discharge port 11b to the second pressure action chamber 14b, the piston 15 starts to move toward the head cover 12. Then, the fluid in the first pressure action chamber 14a is discharged to the outside through the first fluid supply / discharge port 11a, and the piston 15 moves until it reaches the stroke end on the head cover 12 side. As a result, the piston rod 18 moves in the direction of being immersed in the cylinder tube 11.

As shown in FIG. 4, when the piston 15 reaches the stroke end on the head cover 12 side, the end surface 22e of the deformed portion 22 of the cushioning member 20 comes into contact with the head cover 12. As a result, the deformed portion 22 is crushed and elastically deformed so as to bulge toward the locking claw 31, and the strain energy of the cushioning member 20 increases, so that the impact force applied to the piston 15 or the head cover 12 is applied to the cushioning member. Absorbed by 20, the piston 15 stops bufferingly at the stroke end on the head cover 12 side.

As shown in FIG. 5, even if the deformed portion 22 is crushed and elastically deformed so as to bulge toward the locking claw 31, the portion of the deformed portion 22 facing the locking claw 31 becomes the tapered portion 23. Therefore, the deformed portion 22 does not come into contact with the locking claw 31. Therefore, the tapered portion 23 is a relief portion for suppressing the deformed portion 22 from coming into contact with the locking claw 31 when the deformed portion 22 is crushed and elastically deformed so as to bulge toward the locking claw 31. is there. Therefore, the deformed portion 22 comes into contact with the locking claw 31 at the portion of the deformed portion 22 facing the locking claw 31 when the deformed portion 22 is crushed and elastically deformed so as to bulge toward the locking claw 31. A relief portion is provided to prevent this from happening.

Further, as the deformed portion 22 is crushed and elastically deformed, the flange 21 is also elastically deformed. The elastic deformation of the flange 21 is performed until the outer peripheral surface 21a of the flange 21 comes into contact with the inner peripheral surface 30a of the accommodating recess 30. When the outer peripheral surface 21a of the flange 21 comes into contact with the inner peripheral surface 30a of the accommodating recess 30, the flange 21 is not elastically deformed, and in the cushioning member 20, only the elastic deformation of the deformed portion 22 is continued, and the deformed portion is formed. 22 is elastically deformed so as to bulge toward the locking claw 31.

Then, when the maximum strain energy is applied to the cushioning member 20, the deformed portion 22 and the locking claw 31 are in a non-contact state. Therefore, in the present embodiment, the tapered portion 23 has a shape that ensures a non-contact state between the deformed portion 22 and the locking claw 31 even when the maximum strain energy is applied to the cushioning member 20.

Further, when the maximum strain energy is applied to the cushioning member 20, the end face 15b of the piston 15 and the head cover 12 are in a non-contact state. Therefore, in the present embodiment, the amount of protrusion of the deformed portion 22 from the flange 21 ensures a non-contact state between the end surface 15b of the piston 15 and the head cover 12 even when the maximum strain energy is applied to the cushioning member 20. The amount is set. Further, even if the deformed portion 22 is crushed and elastically deformed and the end surface 15b of the piston 15 comes into contact with the head cover 12, the deformed portion 22 and the locking claw 31 are not in contact with each other. Therefore, in the present embodiment, even if the deformed portion 22 is elastically deformed and the end surface 15b of the piston 15 comes into contact with the head cover 12, the tapered portion 23 ensures a non-contact state between the deformed portion 22 and the locking claw 31. It is in the shape of being.

As shown by the alternate long and short dash line in FIG. 2, the tapered portion 23 is not formed in the deformed portion 22, and the outer diameter of the deformed portion 22 is, for example, the same outer diameter as the boundary portion between the tapered portion 23 and the flange 21. Consider the case where the deformed portion 22 is a certain columnar shape. In the case of the conventional examples of FIGS. 11 (a) and 11 (b), the deformed portion 22 is pushed as compared with the case where the tapered portion 23 is formed in the deformed portion 22 as in the present embodiment. While being crushed and elastically deformed so as to bulge toward the locking claw 31, the deformed portion 22 easily comes into contact with the locking claw 31.

In FIG. 6, the solid line L1 shows the relationship between the drag force acting on the head cover 12 from the cushioning member 20 in the present embodiment and the amount of deformation of the cushioning member 20, and the two-dot chain line L2 shows the relationship between FIGS. 11 (a) and 11 (a). The relationship between the drag force acting on the head cover 12 from the cushioning member 20 and the amount of deformation of the cushioning member 20 in the comparative example shown in the conventional example of b) is shown. As shown in FIG. 6, as the deformed portion 22 is elastically deformed and the amount of deformation of the deformed portion 22 increases, the drag force acting on the head cover 12 from the cushioning member 20 gradually increases. When the deformed portion 22 comes into contact with the locking claw 31, the drag force acting on the head cover 12 from the cushioning member 20 is less likely to be elastically deformed, so that the drag force is rapidly increased. Here, in the present embodiment, even if the deformed portion 22 is crushed and elastically deformed so as to bulge toward the locking claw 31, the deformed portion 22 does not come into contact with the locking claw 31, so that the deformed portion 22 is deformed. Even if the amount is increased, the amount of increase in the drag force acting on the head cover 12 from the cushioning member 20 is smaller than that in the comparative example.

In FIG. 7, the solid line L11 shows the relationship between the drag force acting on the head cover 12 from the cushioning member 20 in the present embodiment and the strain energy of the cushioning member 20, and the two-dot chain line L12 shows the relationship between the cushioning member 20 and the head cover 12 in the comparative example. The relationship between the drag force acting on the buffer member 20 and the strain energy of the buffer member 20 is shown. As shown in FIG. 7, in the present embodiment, even if the strain energy due to the deformation amount of the deformed portion 22 increases, the increase amount of the drag force acting on the head cover 12 from the cushioning member 20 is smaller than that of the comparative example. It is possible to increase the strain energy of the cushioning member 20 while suppressing the drag force acting on the head cover 12 from 20.

In the above embodiment, the following effects can be obtained.
(1) At the portion of the deformed portion 22 facing the locking claw 31, when the deformed portion 22 is crushed and elastically deformed so as to bulge toward the locking claw 31, the deformed portion 22 becomes the locking claw 31. A tapered portion 23, which is a relief portion for suppressing contact, is provided. According to this, as compared with the case where the tapered portion 23 is not provided, the deformed portion 22 is locked while the deformed portion 22 is crushed and elastically deformed so as to bulge toward the locking claw 31. Contact with the claw 31 is suppressed. As a result, even if the amount of deformation of the deformed portion 22 increases, the drag force acting on the head cover 12 from the cushioning member 20 can be suppressed. Therefore, the strain energy of the cushioning member 20 can be increased while suppressing the drag force acting on the head cover 12 from the cushioning member 20. As a result, the drag force acting on the head cover 12 from the cushioning member 20 can be suppressed, and the impact force applied to the piston 15 or the head cover 12 can be stably absorbed by the cushioning member 20.

(2) The tapered portion 23 has a shape that ensures a non-contact state between the deformed portion 22 and the locking claw 31 even when the maximum strain energy is applied to the cushioning member 20. Further, the amount of protrusion of the deformed portion 22 from the flange 21 is set to an amount of protrusion that ensures a non-contact state between the end face 15b of the piston 15 and the head cover 12 even when the maximum strain energy is applied to the cushioning member 20. There is. According to this, the drag force acting on the head cover 12 from the cushioning member 20 when the maximum strain energy is applied to the cushioning member 20 can be efficiently reduced. Further, the axial dimension of the cylinder tube 11 can be set to be the shortest.

(3) The tapered portion 23 has a shape that ensures a non-contact state between the deformed portion 22 and the locking claw 31 even if the deformed portion 22 is elastically deformed and the end surface 15b of the piston 15 comes into contact with the head cover 12. It has become. According to this, when the deformed portion 22 is elastically deformed and the end surface 15b of the piston 15 comes into contact with the head cover 12, the cushioning member 20 is compared with the case where the deformed portion 22 and the locking claw 31 are in contact with each other. It is possible to easily reduce the drag force acting on the head cover 12 from the cushioning member 20 when the maximum strain energy is applied to the head cover 12.

(4) The tapered portion 23 is provided at a portion of the deformed portion 22 facing the locking claw 31. According to this, for example, the shape of the piston 15 is not complicated as compared with the case where the tapered portion, which is a relief portion, is provided at the portion of the locking claw 31 facing the deformed portion 22, and the piston 15 is formed. Can be made easy.

(5) A tapered portion 23, which is inclined so as to be separated from the locking claw 31 as it is separated from the flange 21, is provided as a relief portion at a portion of the deformed portion 22 facing the locking claw 31. According to this, for example, the shape of the cushioning member 20 is not complicated as compared with the case where the deformed portion 22 is provided with a curved portion recessed in an arc shape in a direction away from the locking claw 31 as a relief portion. The cushioning member 20 can be easily molded.

(6) Since the drag force acting on the head cover 12 from the cushioning member 20 can be suppressed, the outer diameter of the cushioning member 20 becomes larger with respect to the thickness of the cushioning member 20, and the cushioning member 20 is less likely to be elastically deformed. Even if there is, it is possible to prevent a large impact force from being applied to the piston 15 or the head cover 12.

(7) Since the drag force acting on the head cover 12 from the cushioning member 20 can be suppressed and the impact force applied to the piston 15 can be stably absorbed by the cushioning member 20, the piston 15 becomes smaller and the piston 15 becomes smaller. Even if the operating speed is increased, it is possible to prevent the impact force applied to the piston 15 from becoming larger than the size of the piston 15.

(8) In order to suppress the drag force acting on the head cover 12 from the cushioning member 20, for example, it is not necessary to increase the thickness of the cushioning member 20, so that the fluid pressure cylinder 10 can be miniaturized.

The above embodiment can be modified and implemented as follows. The above embodiment and the following modified examples can be implemented in combination with each other within a technically consistent range.

As shown in FIG. 8, instead of providing the tapered portion 23 on the deformed portion 22, a tapered portion 33 which is a relief portion may be provided at a portion of the locking claw 31 facing the deformed portion 22. The tapered portion 33 is inclined so as to be separated from the deformed portion 22 toward the opening of the accommodating recess 30. According to this, as compared with the case where the tapered portion 33 is not provided, the deformed portion 22 is locked while the deformed portion 22 is crushed and elastically deformed so as to bulge toward the locking claw 31. Contact with the claw 31 is suppressed.

In the embodiment, the tapered portion 23 is provided at the portion of the deformed portion 22 facing the locking claw 31, and the tapered portion 33 is also provided at the portion of the locking claw 31 facing the deformed portion 22. It may be. In short, a relief portion may be provided at least one of the portion of the deformed portion 22 facing the locking claw 31 and the portion of the locking claw 31 facing the deformed portion 22.

As shown in FIG. 9, even if the cushioning member 20 further has an accommodating recess side relief portion 22a that prevents the cushioning member 20 from coming into contact with the inner peripheral surface 30a of the accommodating recess 30 when the cushioning member 20 is elastically deformed. Good. In the embodiment shown in FIG. 9, the cushioning member 20 has three contact portions 41. The outer surfaces of the three contact portions 41 have a semicircular shape that bulges from a portion of the deformed portion 22 that is opposite to the end surface 22e of the deformed portion 22 with respect to the tapered portion 23. The three contact portions 41 are arranged at intervals of 120 degrees in the circumferential direction of the cushioning member 20. The three contact portions 41 function as flanges that can be locked to the locking claws 31 and come into contact with the inner peripheral surface 30a of the accommodating recess 30 to position the accommodating recess 30 in the cushioning member 20. The accommodating recess side relief portion 22a is a portion of the deformed portion 22 that is opposite to the end surface 22e of the deformed portion 22 than the tapered portion 23, and is a portion that connects the contact portions 41 adjacent to each other in the circumferential direction of the cushioning member 20. Is.

Then, even if the housing recess side relief portion 22a is elastically deformed so as to bulge toward the inner peripheral surface 30a of the storage recess 30 as the deformed portion 22 is crushed, the storage recess side relief portion 22a remains in the storage recess 30. It is designed so as not to come into contact with the inner peripheral surface 30a of the. In FIG. 6, the relationship between the drag force acting on the head cover 12 from the cushioning member 20 in the embodiment shown in FIG. 9 and the amount of deformation of the cushioning member 20 is shown by the alternate long and short dash line L3. In the embodiment shown in FIG. 9, even if the housing recess side relief portion 22a is elastically deformed so as to bulge toward the inner peripheral surface 30a of the storage recess 30 as the deformed portion 22 is crushed, the storage recess side relief portion 22a is released. The portion 22a does not come into contact with the inner peripheral surface 30a of the accommodating recess 30. Therefore, unlike the embodiment shown in FIG. 3, the entire outer peripheral surface 21a of the flange 21 is not in contact with the inner peripheral surface 30a of the accommodating recess 30 as the deformed portion 22 is crushed and elastically deformed. Even if the amount of deformation of the deformed portion 22 increases, the amount of increase in the drag force acting on the head cover 12 from the cushioning member 20 is smaller than that of the solid line L1.

In FIG. 7, the relationship between the drag force acting on the head cover 12 from the cushioning member 20 in the embodiment shown in FIG. 9 and the strain energy of the cushioning member 20 is shown by the alternate long and short dash line L13. In the embodiment shown in FIG. 9, even if the strain energy due to the deformation amount of the deformed portion 22 increases, the increase amount of the drag force acting on the head cover 12 from the cushioning member 20 is smaller than that of the solid line L11. Therefore, as can be seen by comparing the solid line L11 and the alternate long and short dash line L13 in FIG. 7, it is possible to increase the strain energy of the cushioning member 20 while suppressing the drag acting on the head cover 12 from the cushioning member 20. ..

According to this, the cushioning member 20 further has an accommodating recess side relief portion 22a that prevents the cushioning member 20 from coming into contact with the inner peripheral surface 30a of the accommodating recess 30 when the cushioning member 20 is elastically deformed. The drag force acting on the head cover 12 from 20 can be easily suppressed, and the strain energy of the cushioning member 20 can be easily increased. Further, the positioning accuracy of the cushioning member 20 with respect to the accommodating recess 30 can be improved, and a uniform relief dimension can be ensured, so that the volume reduction of the cushioning member 20 can be reduced.

As shown in FIG. 10, the flange 21 may be composed of a plurality of contact portions 41 and a housing recess side relief portion 42. The accommodating recess side relief portion 42 is annular, and the plurality of contact portions 41 project from the outer peripheral surface 42a of the accommodation recess side relief portion 42, respectively. Even with such a configuration, the same effect as that of the embodiment shown in FIG. 9 can be obtained.

-In the embodiment shown in FIGS. 9 and 10, the number of contact portions 41 is not limited to three, and may be two or four or more.
-For example, the accommodating recess side relief portion may be provided by cutting out a part of the outer peripheral surface of the flange 21.

-In the embodiment, when the maximum strain energy is applied to the cushioning member 20, the deformed portion 22 and the locking claw 31 may be in contact with each other. Therefore, the tapered portion 23 does not have to have a shape that ensures a non-contact state between the deformed portion 22 and the locking claw 31 even when the maximum strain energy is applied to the cushioning member 20.

-In the embodiment, when the maximum strain energy is applied to the cushioning member 20, the end face 15b of the piston 15 and the head cover 12 may be in contact with each other. Therefore, the amount of protrusion of the deformed portion 22 from the flange 21 is set to the amount of protrusion that ensures a non-contact state between the end face 15b of the piston 15 and the head cover 12 even when the maximum strain energy is applied to the cushioning member 20. It does not have to be.

In the embodiment, when the deformed portion 22 is elastically deformed and the end surface 15b of the piston 15 comes into contact with the head cover 12, the deformed portion 22 and the locking claw 31 may be in contact with each other. Therefore, the tapered portion 23 has a shape that ensures a non-contact state between the deformed portion 22 and the locking claw 31 even if the deformed portion 22 is elastically deformed and the end surface 15b of the piston 15 comes into contact with the head cover 12. It does not have to be.

-In the embodiment, for example, the deformed portion 22 may be provided with a curved portion recessed in an arc shape in a direction away from the locking claw 31 as a relief portion.
In the embodiment, the deformed portion 22 may not have the tapered portion 23, and the deformed portion 22 may have a columnar deformed portion 22 having the same outer diameter as the end face 22e of the deformed portion 22. .. In this case, the tapered portion 23 is not formed in the deformed portion 22, and the outer diameter of the deformed portion 22 is, for example, the cylindrical deformed portion 22 having the same outer diameter as the boundary portion with the flange 21 in the tapered portion 23. Compared to a certain case, it is possible to prevent the deformed portion 22 from coming into contact with the locking claw 31 while the deformed portion 22 is crushed and elastically deformed so as to bulge toward the locking claw 31. .. Therefore, the outer peripheral surface of the deformed portion 22 functions as a relief portion for suppressing the deformed portion 22 from coming into contact with the locking claw 31.

In the embodiment, a pair of locking claws 31 may be provided at the open end of the accommodating recess 30 so as to project from the inner peripheral surface 30a of the accommodating recess 30 to the inside of the accommodating recess 30 and to be arranged so as to face each other. .. In short, the locking claw 31 does not have to be annular.

-In the embodiment, for example, a resin cushioning member 20 may be used, and the material of the cushioning member 20 is not particularly limited as long as it is an elastic material.
-In the embodiment, the problem when the fluid pressure cylinder 10 is miniaturized has been described, but it can also be applied to a large fluid pressure cylinder.

10 ... Fluid pressure cylinder, 11 ... Cylinder tube, 12 ... Head cover, 15 ... Piston, 15b ... End face, 20 ... Cushioning member, 21 ... Flange, 22 ... Deformed part, 22a, 42 ... Accommodating recess side relief part, 23, 33 ... Tapered portion that is a relief portion, 30 ... Containment recess, 30a ... Inner peripheral surface, 31 ... Locking claw, 41 ... Contact portion.

Claims (5)

Cylinder tube and
A head cover attached to one end of the cylinder tube and
A piston housed in the cylinder tube so as to be reciprocating,
A cushioning member made of an elastic material provided on an end face of the piston facing the head cover is provided.
A housing recess is formed on the end face of the piston.
A locking claw that projects inside the accommodating recess is provided on the inner peripheral surface of the accommodating recess.
The cushioning member has a flange that can be locked to the locking claw, and a deformed portion that is continuous with the flange and projects outward from the accommodating recess via the inside of the locking claw.
A fluid pressure cylinder that absorbs the impact force applied to the piston or the head cover by the cushioning member by elastically deforming the deformed portion so as to abut and crush the head cover and bulge toward the locking claw. There,
The deformed portion is crushed and bulges toward the locking claw at at least one of the portion of the deformed portion facing the locking claw and the portion of the locking claw facing the deformed portion. A relief portion is provided to prevent the deformed portion from coming into contact with the locking claw when elastically deformed .
The relief portion has a shape that ensures a non-contact state between the deformed portion and the locking claw even when the maximum strain energy is applied to the cushioning member.
The amount of protrusion from the flange at the deformed portion is set to an amount that ensures a non-contact state between the end face of the piston and the head cover even when the maximum strain energy is applied to the cushioning member. A featured fluid pressure cylinder. Cylinder tube and
A head cover attached to one end of the cylinder tube and
A piston housed in the cylinder tube so as to be reciprocating,
A cushioning member made of an elastic material provided on an end face of the piston facing the head cover is provided.
A housing recess is formed on the end face of the piston.
A locking claw that projects inside the accommodating recess is provided on the inner peripheral surface of the accommodating recess.
The cushioning member has a flange that can be locked to the locking claw, and a deformed portion that is continuous with the flange and projects outward from the accommodating recess via the inside of the locking claw.
A fluid pressure cylinder that absorbs the impact force applied to the piston or the head cover by the cushioning member by elastically deforming the deformed portion so as to abut and crush the head cover and bulge toward the locking claw. There,
The deformed portion is crushed and bulges toward the locking claw at at least one of the portion of the deformed portion facing the locking claw and the portion of the locking claw facing the deformed portion. A relief portion is provided to prevent the deformed portion from coming into contact with the locking claw when elastically deformed.
The relief portion is characterized in that even if the deformed portion is elastically deformed and the end face of the piston comes into contact with the head cover, a non-contact state between the deformed portion and the locking claw is ensured. It shall be the flow body pressure cylinder. The fluid pressure cylinder according to claim 1 or 2 , wherein the relief portion is provided at a portion of the deformed portion facing the locking claw. The fluid pressure cylinder according to claim 3 , wherein the relief portion is a tapered portion that inclines so as to separate from the locking claw as it separates from the flange. Claims 1 to claim that the cushioning member further has an accommodating recess side relief portion that suppresses contact with the inner peripheral surface of the accommodating recess when the cushioning member is elastically deformed. 4. The fluid pressure cylinder according to any one of 4.

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