Fluid Pressure Cylinder

Abstract

To provide a fluid pressure cylinder which can prevent the come-off of a bearing by a simple structure.SOLUTION: A hydraulic cylinder comprises a cylinder head 40 which blocks an end part opening of a cylinder tube, and in which an insertion hole inserted with a piston rod 30 is formed, a bearing 55 arranged at the cylinder head 40, and slidably supporting the piston rod 30, and a rod-side chamber defined between the cylinder head 40 and a piston. The cylinder head 40 has a bearing accommodation groove 51 formed at an internal peripheral face of the insertion hole, and accommodated with the bearing 55. The bearing accommodation groove 51 has a groove bottom part 511 on which an external peripheral face of the bearing 55 abuts, and a retention wall 512 for regulating the come-off of the bearing 55 to the rod-side chamber side. A height h1 of the retention wall 512 is higher than a clearance c1 between the bearing 55 and the piston rod 30.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a fluid pressure cylinder. [Background technology]

[0002] Patent Document 1 discloses a fluid pressure cylinder in which a piston rod to which a piston is fastened is reciprocally disposed within a cylinder tube, the fluid pressure cylinder having a cylinder head that closes an end opening of the cylinder tube, and a bearing is attached to the inner surface of the cylinder head by a snap ring. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2013-199950 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the fluid pressure cylinder described in Patent Document 1, a snap ring must be used to prevent the bearing from coming off when the bearing is mounted on the inner peripheral surface of the cylinder head. This requires a large number of parts to be used to configure the fluid pressure cylinder. Also, a groove must be formed separately to accommodate the snap ring. Thus, the fluid pressure cylinder described in Patent Document 1 has a complex structure to prevent the bearing from coming off.

[0005] The present invention has been made in consideration of the above problems, and has an object to prevent the bearing from coming off with a simple structure. [Means for solving the problem]

[0006] The present invention is a fluid pressure cylinder in which a piston rod provided with a piston is reciprocally provided within a cylinder tube, the fluid pressure cylinder comprising: a closing member that closes an end opening of the cylinder tube and has an insertion hole through which the piston rod is inserted; a bearing that is provided in the closing member and slidably supports the piston rod; and a pressure chamber that is defined between the closing member and the piston. The closing member has a bearing accommodating groove that is formed on the inner circumferential surface of the insertion hole and that accommodates the bearing. The bearing accommodating groove has a groove bottom that is in contact with the outer circumferential surface of the bearing, and a retaining wall that prevents the bearing from coming off into the pressure chamber, the retaining wall having a height greater than a clearance between the bearing and the piston rod. The bearing is press-fitted into the bearing receiving groove, overcoming the retaining wall, and the retaining wall is formed with a first tapered portion that guides the bearing to the bottom of the groove. It is characterized by:

[0007] According to this invention, the height of the retaining wall that prevents the bearing from falling out toward the pressure chamber is greater than the clearance between the bearing and the piston rod, so the bearing is prevented from climbing over the retaining wall and falling out of the bearing accommodating groove. Therefore, it is possible to prevent the bearing from falling out with a simple structure without using a snap ring. Furthermore, since the bearing is smoothly press-fitted into the bearing accommodating groove while being guided by the first tapered portion, mounting ease of the bearing is improved.

[0010] Also, the present invention is characterized in that the retaining wall is formed with a second tapered portion facing the end face of the bearing, and the inclination angle of the second tapered portion is larger than the inclination angle of the first tapered portion.

[0011] According to this invention, the workability of the closing member is improved compared to a bearing accommodating groove in which the second tapered portion is not formed. Also, by making the inclination angle of the second tapered portion larger than the inclination angle of the first tapered portion, the bearing is less likely to come out.

[0012] The present invention also provides a method for producing a method for manufacturing a semiconductor device comprising the steps of: A fluid pressure cylinder in which a piston rod having a piston is reciprocably disposed within a cylinder tube, the fluid pressure cylinder comprising: a closing member that closes an end opening of the cylinder tube and has an insertion hole through which the piston rod is inserted; a bearing that is provided in the closing member and supports the piston rod so that it can slide; and a pressure chamber that is defined between the closing member and the piston. The closing member has a bearing accommodating groove that is formed on the inner peripheral surface of the insertion hole and accommodates the bearing. The bearing accommodating groove has a groove bottom that is in contact with an outer peripheral surface of the bearing, and a stopper wall that prevents the bearing from coming out toward the pressure chamber. a restricting wall that faces the retaining wall and restricts axial movement of the bearing; Have death, The height of the retaining wall is greater than the clearance between the bearing and the piston rod. The restricting wall is characterized in that its height is greater than that of the retaining wall.

[0013] According to the present invention, Since the height of the retaining wall that prevents the bearing from coming out toward the pressure chamber is greater than the clearance between the bearing and the piston rod, the bearing is prevented from climbing over the retaining wall and coming out of the bearing accommodating groove. Therefore, the bearing can be prevented from coming out with a simple structure without using a snap ring.By making the height of the control wall that controls the axial position of the bearing greater than the height of the anti-removal wall, the height of the anti-removal wall can be lowered, thereby minimizing the amount of deformation of the bearing when the bearing is pressed into the bearing accommodating groove. Effect of the Invention

[0014] According to the present invention, it is possible to prevent the bearing from coming off with a simple structure. [Brief description of the drawings]

[0015] [Figure 1] 1 is a cross-sectional view of a fluid pressure cylinder according to an embodiment of the present invention. [Diagram 2] 2 is an enlarged view of a portion A surrounded by a dashed line in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0017] A fluid pressure cylinder according to an embodiment of the present invention will be described with reference to Fig. 1. Below, a case will be described in which the fluid pressure cylinder is a hydraulic cylinder 100 that is driven using hydraulic oil as a working fluid. Fig. 1 is a cross-sectional view of the periphery of a cylinder head 40 of the hydraulic cylinder 100.

[0018] The hydraulic cylinder 100 is used as an actuator mounted on construction machinery or industrial machinery. For example, the hydraulic cylinder 100 is used as an arm cylinder mounted on a hydraulic excavator, and the arm of the hydraulic excavator rotates as the hydraulic cylinder 100 expands and contracts.

[0019] As shown in FIG. 1, a hydraulic cylinder 100 includes a cylindrical cylinder tube 10, a piston 20 that is slidably inserted into the cylinder tube 10 and divides the inside of the cylinder tube 10 into a rod side chamber 11 and a non-rod side chamber 12 that serve as pressure chambers, a piston rod 30 that has one end connected to the piston 20 and the other end extending to the outside of the cylinder tube 10 and reciprocates within the cylinder tube 10, and a cylinder head 40 that serves as a closing member that closes an end opening of the cylinder tube 10.

[0020] The inside of the cylinder tube 10 is partitioned by the piston 20 into two fluid pressure chambers, a rod side chamber 11 and an anti-rod side chamber 12, which serve as pressure chambers. The hydraulic cylinder 100 expands and contracts along the axial direction by hydraulic pressure guided from a hydraulic source to the rod side chamber 11 or the anti-rod side chamber 12. Note that a hydraulic fluid such as a water-soluble substitute liquid may be used instead of oil as the hydraulic oil.

[0021] The cylinder head 40 is a substantially cylindrical member having an insertion hole 41 formed therethrough, through which the piston rod 30 is inserted. The cylinder head 40 is joined to a flange portion 10a formed at the end of the cylinder tube 10 via bolts 39.

[0022] A bearing 55, a sub seal 56, a main seal 57, and a dust seal 58 are arranged in this order on the inner peripheral surface of the insertion hole 41 toward the outside. These come into sliding contact with the outer peripheral surface of the piston rod 30, and the bearing 55 in particular supports the piston rod 30 so that it can slide freely in the axial direction of the cylinder tube 10. In addition, the bearing 55 is a cylindrical bearing made of a mixed material in which resin is dispersed in a metal such as an alloy, and therefore has a certain degree of flexibility.

[0023] Further, the cylinder head 40 is provided with a supply / discharge port 42 for supplying and discharging hydraulic oil to the rod side chamber 11. One end of the supply / discharge port 42 opens to the inner circumferential surface of the insertion hole 41, and the other end of the supply / discharge port 42 opens to the outer surface of the cylinder head 40. The other end of the supply / discharge port 42 is connected to a hydraulic piping (not shown), which is connected to a hydraulic source or a tank via a switching valve.

[0024] The cylinder head 40 is provided with a cylindrical portion 45 that fits into the inner peripheral surface of the flange portion 10a of the cylinder tube 10. An O-ring 59 that seals between the cylinder tube 10 and the cylinder head 40 is provided on the outer peripheral surface of the cylindrical portion 45. The piston 20 abuts against the tip surface of the cylindrical portion 45 when the hydraulic cylinder 100 is fully extended, and functions as a restricting surface that restricts the movement of the piston 20 and the piston rod 30.

[0025] The insertion hole 41 has a first insertion hole 41a through which the cushion ring 34 described below can enter, and a second insertion hole 41b having an inner diameter smaller than that of the first insertion hole 41a. The first insertion hole 41a is provided on the cylindrical portion 45 side, and the second insertion hole 41b is provided on the opposite side to the first insertion hole 41a across the supply / discharge port 42.

[0026] The piston rod 30 has a small diameter section 31 formed at the tip thereof and to which the piston 20 is fastened, a large diameter section 32 having an outer diameter larger than that of the small diameter section 31 and slidably supported by the cylinder head 40, and a medium diameter section 33 formed between the small diameter section 31 and the large diameter section 32 and having a cushion ring 34 disposed on the radially outer side. The outer diameter of the medium diameter section 33 and the inner diameter of the cushion ring 34 are set smaller than the outer diameters of the large diameter section 32 and the piston 20, so that the cushion ring 34 will not come off the piston rod 30.

[0027] The cushion ring 34 is a cylindrical member having an outer diameter that can enter the first insertion hole 41a of the cylinder head 40, and is provided to slow down the movement speed of the piston rod 30 when the hydraulic cylinder 100 reaches its most extended state.

[0028] Next, the operation of the hydraulic cylinder 100 having the above configuration will be described.

[0029] When the anti-rod side chamber 12 is connected to a hydraulic power source and the rod side chamber 11 is connected to a tank, hydraulic oil is supplied to the anti-rod side chamber 12 and the hydraulic oil in the rod side chamber 11 is discharged to the tank through the supply / discharge port 42. As a result, the piston rod 30 moves leftward in FIG. 1 and the hydraulic cylinder 100 extends.

[0030] When the hydraulic cylinder 100 is extended, until the cushion ring 34 enters the first insertion hole 41a, the hydraulic oil in the rod side chamber 11 is guided to the supply / discharge port 42 through a passage having a relatively large cross-sectional area formed between the outer circumferential surface of the large diameter portion 32 and the inner circumferential surface of the first insertion hole 41a. Therefore, the piston rod 30 can move at a relatively high speed.

[0031] When the hydraulic cylinder 100 is further extended and the cushion ring 34 enters the first insertion hole 41a, the hydraulic oil in the rod side chamber 11 is guided to the supply and discharge port 42 through a passage with a relatively small cross-sectional area formed between the inner surface of the cushion ring 34 and the outer surface of the medium diameter portion 33, and between the outer surface of the cushion ring 34 and the inner surface of the first insertion hole 41a.

[0032] In this way, if the cross-sectional area of ​​the passage connecting the supply and discharge port 42 and the rod side chamber 11 is small, resistance is applied to the flow of hydraulic oil toward the supply and discharge port 42, resulting in an increase in pressure in the rod side chamber 11 and a slower movement speed of the piston rod 30.

[0033] Furthermore, as the cushion ring 34 enters the first insertion hole 41a, the cross-sectional area of ​​the passage connecting the supply / discharge port 42 and the rod side chamber 11 gradually decreases, further slowing down the moving speed of the piston rod 30. In this way, the cushioning effect of the cushion ring 34 is exerted, preventing the piston 20 from colliding with the cylinder head 40 with force.

[0034] On the other hand, when the rod side chamber 11 is connected to the hydraulic power source and the anti-rod side chamber 12 is connected to the tank, hydraulic oil is supplied to the rod side chamber 11 through the supply / discharge port 42, and hydraulic oil in the anti-rod side chamber 12 is discharged to the tank. This causes the piston rod 30 to move rightward in FIG. 1, causing the hydraulic cylinder 100 to contract.

[0035] Next, the second insertion hole 41b will be described with reference to FIGS.

[0036] 1 and 2, a bearing accommodating groove 51, a sub-seal accommodating groove 52, a main seal accommodating groove 53, and a dust seal accommodating groove 54 are formed in the inner circumferential surface of the second insertion hole 41b, lined up in this order toward the outside. The bearing 55, the sub-seal 56, the main seal 57, and the dust seal 58 are accommodated (mounted) in the bearing accommodating groove 51, the sub-seal accommodating groove 52, the main seal accommodating groove 53, and the dust seal accommodating groove 54, respectively. The sub-seal 56, the main seal 57, and the dust seal 58 are in sliding contact with the outer circumferential surface of the piston rod 30.

[0037] As shown in Figure 2, the bearing accommodating groove 51 has a groove bottom 511 formed extending along the axial direction, a slip-out prevention wall 512 provided on one axial side of the groove bottom 511 and defining the bearing accommodating groove 51, and a regulating wall 513 provided on the other axial side of the groove bottom 511 and defining the bearing accommodating groove 51.

[0038] The groove bottom 511 is formed so that its diameter is approximately equal to the outer diameter of the bearing 55. As a result, when the bearing 55 is accommodated in the bearing accommodating groove 51, the outer circumferential surface of the bearing 55 abuts against the groove bottom 511. The groove bottom 511 is also formed so that its diameter is smaller than the inner diameter of the first insertion hole 41a. In other words, the first insertion hole 41a is formed so that its inner diameter is larger than the outer diameter of the bearing 55. As a result, the bearing 55 can smoothly pass through the first insertion hole 41a and enter the second insertion hole 41b without being pressed in.

[0039] The retaining wall 512 is an annular wall portion for preventing the bearing 55 from coming out toward the rod side chamber 11. The retaining wall 512 is formed to protrude radially from the groove bottom 511 toward the axis O. When the large diameter portion 32 of the piston rod 30 is not inserted into the cylinder head 40, the bearing 55 is accommodated in the bearing accommodating groove 51 by being press-fitted over the retaining wall 512.

[0040] In addition, when the large diameter portion 32 of the piston rod 30 is inserted into the cylinder head 40, the height h1 of the retaining wall 512 is larger than the clearance c1 between the bearing 55 accommodated in the bearing accommodating groove 51 and the large diameter portion 32 of the piston rod 30 (see FIG. 2). Specifically, the clearance c1 is the radial dimension between the inner circumferential surface of the bearing 55 and the outer circumferential surface of the large diameter portion 32.

[0041] That is, in a state in which the large diameter portion 32 of the piston rod 30 is inserted through the cylinder head 40, the clearance c3 between the apex 512c of the retaining wall 512 and the large diameter portion 32 of the piston rod 30 is smaller than the thickness d of the bearing 55 (i.e., the dimension between the inner circumferential surface of the bearing 55 and the outer circumferential surface of the bearing 55) (see FIG. 2). As a result, the bearing 55 does not pass through the clearance c3 between the apex 512c of the retaining wall 512 and the large diameter portion 32 of the piston rod 30, and therefore the bearing 55 does not climb over the retaining wall 512 and fall out of the bearing accommodating groove 51.

[0042] Moreover, the height h1 of the retaining wall 512 (i.e., the amount by which the retaining wall 512 protrudes from the groove bottom 511) is smaller than the thickness d of the bearing 55. This allows the height of the retaining wall 512 to be reduced, thereby making it possible to keep the amount of deformation of the bearing 55 during press-fitting small.

[0043] The retaining wall 512 has a first tapered portion 512a that guides the bearing 55 to the groove bottom 511, and a second tapered portion 512b that faces an end face 55a of the bearing 55. In this embodiment, the first tapered portion 512a is directly continuous with the second tapered portion 512b in the axial direction, but is not limited to this, and may be indirectly continuous with the second tapered portion 512b via a flat portion extending along the axial direction, for example.

[0044] The first tapered portion 512a is formed so that the clearance between the first tapered portion 512a and the large diameter portion 32 of the piston rod 30 gradually decreases toward the outside (opposite the piston). As a result, the bearing 55 is smoothly press-fitted into the bearing housing groove 51 while being guided by the first tapered portion 512a. From the viewpoint of improving the ease of press-fitting the bearing 55, the inclination angle α of the first tapered portion 512a is preferably 60° or less, more preferably 45° or less, and even more preferably 30° or less. In this embodiment, the inclination angle α of the first tapered portion 512a is 20°. The inner diameter of the end portion 512d of the first tapered portion 512a is larger than the inner diameter of the groove bottom portion 511. As a result, the bearing 55 can be easily inserted into the bearing housing groove 51.

[0045] On the other hand, the second tapered portion 512b is formed so that the clearance between the second tapered portion 512b and the large diameter portion 32 of the piston rod 30 gradually increases toward the outside. This makes it easier to machine the cylinder head 40 compared to a bearing accommodating groove 51 in which the second tapered portion 512b is not formed. From the viewpoint of making it difficult for the bearing 55 to come off, it is preferable to make the inclination angle β of the second tapered portion 512b larger than the inclination angle α of the first tapered portion 512a. In this embodiment, the inclination angle β of the second tapered portion 512b is 30°.

[0046] The restriction wall 513 is an annular wall portion that faces the retaining wall 512 and restricts the axial movement of the bearing 55. The restriction wall 513 is formed to protrude radially from the groove bottom 511 toward the axis O. The restriction wall 513 has a height h2 (i.e., the amount of protrusion of the restriction wall 513 from the groove bottom 511) that is greater than the height h1 of the retaining wall 512 (see FIG. 2). This allows the height of the retaining wall 512 to be reduced, thereby minimizing the amount of deformation of the bearing 55 during press-fitting.

[0047] When the large diameter portion 32 of the piston rod 30 is inserted into the cylinder head 40, the restricting wall 513 does not come into contact with the large diameter portion 32 of the piston rod 30. A clearance c2 between the restricting wall 513 and the large diameter portion 32 of the piston rod 30 is equal to a clearance c1 between the bearing 55 and the large diameter portion 32 of the piston rod 30 (see FIG. 2).

[0048] That is, in a state where the large diameter portion 32 of the piston rod 30 is inserted into the cylinder head 40, the clearance c2 between the restricting wall 513 and the large diameter portion 32 of the piston rod 30 is smaller than the thickness d of the bearing 55 (see FIG. 2). As a result, the bearing 55 cannot pass through the clearance c2 between the restricting wall 513 and the large diameter portion 32 of the piston rod 30, and therefore the bearing 55 does not climb over the restricting wall 513 and come out of the bearing accommodating groove 51.

[0049] The configuration, operation, and effects of the embodiments of the present invention will be described below.

[0050] The hydraulic cylinder 100 according to this embodiment is a hydraulic cylinder 100 in which a piston rod 30 provided with a piston 20 is reciprocally provided in a cylinder tube 10, and includes a cylinder head 40 that closes an end opening of the cylinder tube 10 and has an insertion hole 41 through which the piston rod 30 is inserted, a bearing 55 provided in the cylinder head 40 and slidably supporting the piston rod 30, and a rod side chamber 11 defined between the cylinder head 40 and the piston 20. The cylinder head 40 has a bearing accommodation groove 51 formed on the inner peripheral surface of the insertion hole 41 and in which the bearing 55 is accommodated. The bearing accommodation groove 51 has a groove bottom 511 against which the outer peripheral surface of the bearing 55 abuts, and a retaining wall 512 that restricts the bearing 55 from coming off to the rod side chamber 11, and the retaining wall 512 has a height greater than the clearance between the bearing 55 and the piston rod 30.

[0051] According to this configuration, the bearing accommodating groove 51 is formed on the inner circumferential surface of the insertion hole 41 of the cylinder head 40, so that the bearing 55 is accommodated in the bearing accommodating groove 51 by press-fitting when the piston rod 30 is not inserted into the insertion hole 41 of the cylinder head 40. Also, the height h1 of the retaining wall 512 that restricts the bearing 55 from coming out toward the rod-side chamber 11 is greater than the clearance c1 between the bearing 55 and the piston rod 30. Therefore, when the piston rod 30 is inserted into the insertion hole 41 of the cylinder head 40, the bearing 55 does not climb over the retaining wall 512 and come out of the bearing accommodating groove 51. Therefore, the bearing 55 can be prevented from coming out with a simple configuration without using a snap ring.

[0052] In this embodiment, the bearing 55 is accommodated in the bearing accommodating groove 51 by press-fitting via the retaining wall 512, and the retaining wall 512 is formed with a first tapered portion 512a that guides the bearing 55 to the groove bottom 511.

[0053] According to this configuration, the bearing 55 is smoothly press-fitted into the bearing accommodating groove 51 while being guided by the first tapered portion 512a, so that the mounting ease of the bearing 55 is improved.

[0054] In this embodiment, the retaining wall 512 is formed with a second tapered portion 512b that faces the end face of the bearing 55, and the inclination angle β of the second tapered portion 512b is larger than the inclination angle α of the first tapered portion 512a.

[0055] This configuration improves the workability of the cylinder head 40 compared to a bearing accommodating groove 51 in which the second tapered portion 512b is not formed. Also, by making the inclination angle β of the second tapered portion 512b larger than the inclination angle α of the first tapered portion 512a, the bearing 55 is less likely to come out.

[0056] In this embodiment, the bearing accommodating groove 51 further has a restriction wall 513 that faces the retaining wall 512 and restricts axial movement of the bearing 55, and the height h2 of the restriction wall 513 is greater than the height h1 of the retaining wall 512. This allows the height of the retaining wall 512 to be reduced, thereby minimizing the amount of deformation of the bearing 55 during press-fitting.

[0057] Although the present embodiment has been described above, the above embodiment merely illustrates some of the application examples of the present invention, and is not intended to limit the technical scope of the present invention to the specific configurations of the above embodiment.

[0058] (Modification) In the above embodiment, the anti-pullout wall 512 is formed around the entire circumference of the ring, but this is not limited to this. For example, the anti-pullout wall 512 may be formed around a part of the ring, or may be formed as multiple walls around the ring at a predetermined interval.

[0059] In the above embodiment, the retaining wall 512 is formed with the first tapered portion 512a and the second tapered portion 512b continuing from the first tapered portion 512a, but is not limited thereto, and for example, the second tapered portion 512b may not be formed and only the first tapered portion 512a may be formed. In this case, compared to the retaining wall 512 in which the first tapered portion 512a and the second tapered portion 512b are formed, the space for forming the second tapered portion 512b can be saved, and therefore the bearing accommodating groove 51 can be made smaller in the axial direction.

[0060] In the above embodiment, the restricting wall 513 is provided so that the clearance c2 between the restricting wall 513 and the large diameter portion 32 of the piston rod 30 is equal to the clearance c1 between the bearing 55 and the large diameter portion 32 of the piston rod 30, but this is not limiting, and for example, the restricting wall 513 may be provided so that the clearance c2 between the restricting wall 513 and the large diameter portion 32 of the piston rod 30 is larger than the clearance c1 between the bearing 55 and the large diameter portion 32 of the piston rod 30. In this case, it is possible to prevent the restricting wall 513 and the large diameter portion 32 of the piston rod 30 from coming into contact with each other. [Explanation of symbols]

[0061] 10 cylinder tube, 20 piston, 30 piston rod, 40 cylinder head (blocking member), 51 bearing accommodation groove, 55 bearing, 511 groove bottom, 512 stopper wall, 513 regulating wall, 512a first tapered portion, 512b second tapered portion, 100 hydraulic cylinder (fluid pressure cylinder)

Claims

1. A fluid pressure cylinder in which a piston rod having a piston is reciprocally disposed within a cylinder tube, a closing member that closes an end opening of the cylinder tube and has an insertion hole through which the piston rod is inserted; a bearing provided in the blocking member and configured to slidably support the piston rod; a pressure chamber defined between the closing member and the piston, the blocking member has a bearing accommodating groove formed on an inner circumferential surface of the insertion hole and configured to accommodate the bearing, The bearing accommodating groove is a groove bottom portion against which an outer peripheral surface of the bearing abuts; a retaining wall that prevents the bearing from coming out toward the pressure chamber, The height of the retaining wall is greater than the clearance between the bearing and the piston rod, The bearing is press-fitted into the bearing accommodating groove, overcoming the retaining wall. a first tapered portion formed on the retaining wall for guiding the bearing to the bottom of the groove,

2. The retaining wall is formed with a second tapered portion facing an end surface of the bearing, 2. The fluid pressure cylinder according to claim 1, wherein an inclination angle of the second tapered portion is larger than an inclination angle of the first tapered portion.

3. A fluid pressure cylinder having a piston rod provided with a piston and capable of reciprocating within a cylinder tube, a closing member that closes an end opening of the cylinder tube and has an insertion hole through which the piston rod is inserted; a bearing provided in the blocking member and configured to slidably support the piston rod; a pressure chamber defined between the closing member and the piston, the blocking member has a bearing accommodating groove formed on an inner circumferential surface of the insertion hole and configured to accommodate the bearing, The bearing accommodating groove is a groove bottom portion against which an outer peripheral surface of the bearing abuts; a retaining wall that prevents the bearing from coming out toward the pressure chamber; a restriction wall that faces the fall-out prevention wall and restricts axial movement of the bearing, The height of the retaining wall is greater than the clearance between the bearing and the piston rod, A fluid pressure cylinder, wherein the regulating wall has a height greater than a height of the retaining wall.

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