Fluid pressure cylinder and method of manufacturing the fluid pressure cylinder

Abstract

To improve a degree of freedom in design of a fluid pressure cylinder and attachability of a cushion ring.SOLUTION: A fluid pressure cylinder 100 includes a cylinder tube 10, a movement member 40 slidably inserted in the cylinder tube 10, a reception 13b provided at one of the cylinder tube 10 and the movement member 40 and allowing entry of the other in the vicinity of a stroke end of the movement member 40, a first cushion ring 50 attached to the reception 13b so as to decelerate the movement member 40 in the vicinity of the stroke end, and a snap ring 70 provided on an inner peripheral surface of the reception 13b and engaged with an outer peripheral surface of the first cushion ring 50 so as to prevent the first cushion ring 50 from falling off. The first cushion ring 50 includes a tapered portion 54 formed on an outer peripheral surface of one end 53, and a groove 56 serving as a transmission portion to which turning force is transmitted so that the cushion ring is attached to the reception 13b from the tapered portion 54.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a fluid pressure cylinder and a method for manufacturing a fluid pressure cylinder. [Background technology]

[0002] Patent Document 1 discloses a fluid pressure cylinder including a cylinder tube having an internal cylinder chamber, a pair of end blocks attached to both ends of the cylinder tube to close the cylinder chamber, and a piston provided in the cylinder chamber and displaceable along the axial direction of the cylinder tube. One end of a piston rod is inserted into the piston. A cylindrical cushion ring is attached to the piston rod near the piston, and can be inserted into a rod hole provided in the end block. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-238269 Summary of the Invention [Problem to be solved by the invention]

[0004] In a fluid pressure cylinder such as that described in Patent Document 1, it is also conceivable to provide a cushion ring in the rod hole rather than in the vicinity of the piston in the piston rod. In this case, a snap ring that engages with the outer circumferential surface of the cushion ring is generally provided on the inner circumferential surface of the rod hole to prevent the cushion ring from falling off. When the cushion ring is inserted into the rod hole, it slides over the inner circumferential surface of the snap ring, which hinders insertion of the cushion ring into the rod hole. Therefore, it is conceivable to provide a tapered portion on the axial end of the cushion ring to reduce the diameter of the tip end, and then insert the cushion ring from the tip end, making it easier to insert the cushion ring into the rod hole.

[0005] If the angle of the tapered portion of the cushion ring is reduced, the cushion ring can be inserted with less force and is easier to install, but the tapered portion becomes longer in the axial direction, making the cushion ring longer, thereby reducing the design freedom of the fluid pressure cylinder. Conversely, if the angle of the tapered portion of the cushion ring is increased, the axial length of the tapered portion becomes shorter, making the cushion ring shorter, thereby increasing the design freedom of the fluid pressure cylinder, but requiring more force to insert the cushion ring, making installation of the cushion ring more difficult. As such, it is difficult to achieve both the design freedom of the fluid pressure cylinder and the ease of installation of the cushion ring.

[0006] The present invention has been made in view of the above problems, and has as its object to improve the degree of freedom in designing a fluid pressure cylinder and the ease of mounting a cushion ring. [Means for solving the problem]

[0007] The present invention relates to a cylinder tube, a moving member slidably inserted into the cylinder tube, a receiving portion provided on one of the cylinder tube and the moving member to allow the other to enter near the stroke end of the moving member, a cushion ring attached to the receiving portion to decelerate the moving member near the stroke end, and a cushion ring provided on the inner peripheral surface of the receiving portion. The first annular groove Established 、 a snap ring that engages with the outer peripheral surface of the cushion ring to prevent the cushion ring from falling off, the cushion ring having an inclined portion formed on the outer peripheral surface of one end thereof, a transmission portion to which a rotational force is transmitted for attaching the cushion ring from the inclined portion to the receiving portion, a second annular groove provided on the outer peripheral surface and capable of accommodating a portion of the snap ring; With The snap ring is received across the first annular groove of the receiving portion and the second annular groove of the cushion ring. It is characterized by:

[0008] In this invention, the rotational force is transmitted to the transmission section, and the cushion ring is attached to the receiving section of the cylinder tube or the moving member through the inclined section. This allows force to be applied to the cushion ring not only in the insertion direction but also in the rotational direction during attachment, making it easier for the snap ring to expand and for the cushion ring to be attached. Therefore, the cushion ring can be easily attached even if the angle of the inclined section is increased and the axial length of the tapered section is shortened. This improves the design freedom of the fluid pressure cylinder and the ease of attaching the cushion ring.

[0009] The present invention provides a receiving portion provided on one of the cylinder tube and the moving member to allow the other to enter near the stroke end of the moving member; a cushion ring attached to the receiving portion for decelerating the moving member near the stroke end; and a snap ring provided on the inner peripheral surface of the receiving portion for engaging with the outer peripheral surface of the cushion ring to prevent the cushion ring from falling off, wherein the cushion ring has an inclined portion formed on the outer peripheral surface of one end thereof, and a transmission portion to which a rotational force is transmitted for attaching the cushion ring from the inclined portion to the receiving portion, The transmission portion of the cushion ring is characterized by being a groove formed in the other end portion of the cushion ring.

[0010] In this invention, The cushion ring is attached to the receiving portion of the cylinder tube or the moving member through the inclined portion, with the rotational force transmitted to the transmission portion. This allows the force to be applied to the cushion ring not only in the insertion direction but also in the rotational direction during attachment, making it easier for the snap ring to expand and for the cushion ring to be attached. Therefore, the cushion ring can be easily attached even if the angle of the inclined portion is increased and the axial length of the tapered portion is shortened. This improves the degree of freedom in the design of the fluid pressure cylinder and the ease of attaching the cushion ring. Furthermore, The grooves allow rotational force to be transmitted to the cushion ring more reliably.

[0011] The present invention is characterized in that the cylinder tube has a cylindrical main body portion, a head member that closes an opening at one end of the main body portion and through which a movable member is inserted, and a bottom member that closes an opening at the other end of the main body portion, and the receiving portion is provided on one of the bottom member and the movable member.

[0012] According to the present invention, in a fluid pressure cylinder equipped with a cushion ring for decelerating a moving member at the stroke end in the direction in which the moving member contracts, it is possible to improve the degree of freedom in designing the fluid pressure cylinder and the ease of attaching the cushion ring.

[0013] The present invention is a method for manufacturing a fluid pressure cylinder comprising: a cylinder tube; a movable member slidably inserted into the cylinder tube; a receiving portion provided on one of the cylinder tube or the movable member and allowing the other to enter near the stroke end of the movable member; a cushion ring attached to the receiving portion for decelerating the movable member near the stroke end; and a snap ring provided on the inner peripheral surface of the receiving portion and engaging with the outer peripheral surface of the cushion ring to prevent the cushion ring from falling off, the cushion ring having an inclined portion formed on the outer peripheral surface at one end, characterized in that a jig is engaged with the cushion ring, and the cushion ring is rotated and pushed in via the jig to attach it to the receiving portion from the inclined portion.

[0014] In this invention, the cushion ring is attached to the receiving portion of the cylinder tube or the moving member by being pushed in while being rotated via a jig, and the inclined portion is attached to the receiving portion of the cylinder tube or the moving member. This applies force to the cushion ring not only in the insertion direction but also in the rotational direction during attachment, making it easier for the snap ring to expand and for the cushion ring to be attached. Therefore, the cushion ring can be easily attached even if the angle of the inclined portion is large and the axial length of the tapered portion is short.

[0015] The present invention is characterized in that the jig has a hook portion that engages circumferentially with a groove formed in the other end of the cushion ring.

[0016] In this invention, the hook portion of the jig engages with the groove of the cushion ring, so that the jig is securely locked by the cushion ring. [Effects of the Invention]

[0017] According to the present invention, it is possible to improve the degree of freedom in designing a fluid pressure cylinder and the ease of mounting a cushion ring. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a partial cross-sectional view of a fluid pressure cylinder according to an embodiment of the present invention. [Figure 2] FIG. 2 is an enlarged view of A shown in FIG. [Figure 3] FIG. [Figure 4] FIG. [Figure 5] FIG. 10 is a partial cross-sectional view showing how the cushion ring is attached using a jig. DETAILED DESCRIPTION OF THE INVENTION

[0019] A fluid pressure cylinder according to an embodiment of the present invention will be described with reference to the drawings. In the following, 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.

[0020] First, the overall configuration of the hydraulic cylinder 100 will be described with reference to FIGS.

[0021] 1, the hydraulic cylinder 100 includes a cylinder tube 10, a piston rod 20 inserted into the cylinder tube 10 so as to be able to move back and forth, and a piston 30 connected to the piston rod 20 and sliding along the inner circumferential surface of the cylinder tube 10. The piston rod 20 and the piston 30 form a moving member 40. In other words, the moving member 40 is inserted into the cylinder tube 10 so as to be able to slide freely.

[0022] The cylinder tube 10 has a cylindrical main body 11, a cylinder head 12 as a head member that closes an opening at one end of the main body 11 and through which a piston rod 20 is inserted, and a cylinder bottom 13 as a bottom member that closes an opening at the other end of the main body 11. A flange 12a of the cylinder head 12 is fastened to the main body 11 via a plurality of fastening members (not shown) such as bolts. The cylinder bottom 13 is joined to the main body 11 by, for example, welding. The main body 11, the cylinder head 12, and the piston 30 define a rod-side chamber 2, and the main body 11, the cylinder bottom 13, and the piston 30 define a counter-rod-side chamber 3.

[0023] The cylinder head 12 is formed in an annular shape and slidably supports the piston rod 20. The inner diameter of the cylinder head 12 is larger than the outer diameter of the piston rod 20 (specifically, the rod main body 21 described below). Therefore, an annular passage 12b is formed by the inner peripheral surface of the cylinder head 12 and the outer peripheral surface of the piston rod 20. In addition, the cylinder head 12 is formed with a head-side port 12c as a supply / discharge port that communicates with the rod-side chamber 2 through the passage 12b.

[0024] The cylinder bottom 13 is formed with a bottom-side port 13a as a supply / discharge port that communicates with the anti-rod-side chamber 3. The cylinder bottom 13 is also provided with a receiving portion 13b that allows the piston rod 20 to enter near the stroke end of the piston rod 20. The receiving portion 13b is a hole that extends along the axial direction of the cylinder bottom 13 and has a circular radial cross section. The receiving portion 13b communicates with the bottom-side port 13a. A first cushion ring 50 is provided in the receiving portion 13b, and the piston rod 20 is decelerated near the stroke end in the retraction direction by a portion of the piston rod 20 entering the first cushion ring 50 provided in the receiving portion 13b. The cushioning effect by which the piston rod 20 is decelerated and the configuration of the receiving portion 13b will be described in detail below.

[0025] The piston rod 20 includes a rod main body 21 slidably supported by the cylinder head 12, an intermediate portion 22 having a smaller diameter than the rod main body 21, an externally threaded portion 23 having an external thread formed on its outer periphery to engage with the piston 30, and a cushion portion 24 that can enter the receiving portion 13b of the cylinder bottom 13 near the stroke end. In the piston rod 20, the rod main body 21, intermediate portion 22, externally threaded portion 23, and cushion portion 24 are arranged axially in this order. Steps are formed between adjacent rod main bodies 21, intermediate portions 22, externally threaded portion 23, and cushion portions 24. In the piston rod 20, the rod main body 21 has the largest diameter, and the diameters of the rod main body 21, intermediate portion 22, externally threaded portion 23, and cushion portion 24 decrease in this order. The cushion portion 24 has an outer diameter slightly smaller than the inner diameter of the first cushion ring 50. The cushion portion 24 may be formed as a single component together with the rod body 21, the intermediate portion 22, and the male thread portion 23, or may be a separate component that is attached to the male thread portion 23 by welding or the like. In either case, the cushion portion 24 constitutes a part of the piston rod 20.

[0026] A second cushion ring 80 is attached to the outer peripheral surface of the intermediate portion 22 to decelerate the piston rod 20 near the stroke end in the extension direction. The second cushion ring 80 has an inner diameter that is approximately the same as the outer diameter of the intermediate portion 22, and is provided on the piston rod 20 between the piston 30 and a step portion between the intermediate portion 22 and the rod main body 21. The outer diameter of the second cushion ring 80 is larger than the outer diameter of the rod main body 21 and smaller than the inner diameter of the cylinder head 12. The piston rod 20 is decelerated near the stroke end in the extension direction as a result of a portion of the second cushion ring 80 entering the passage 12b. The cushioning action of the second cushion ring 80 to decelerate the piston rod 20 will be described in detail below.

[0027] The piston 30 is formed in an annular shape and has an internal thread formed on its inner circumferential surface. The internal thread of the piston 30 is threadedly engaged with the external thread of the externally threaded portion 23 of the piston rod 20, thereby connecting the piston 30 to the piston rod 20. A seal member 31 is provided on the outer circumferential surface of the piston 30. This blocks communication between the rod-side chamber 2 and the anti-rod-side chamber 3 through a gap between the inner circumferential surface of the main body 11 of the cylinder tube 10 and the outer circumferential surface of the piston 30.

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

[0029] When hydraulic oil is supplied from the hydraulic source (hydraulic fluid pressure source) to the anti-rod-side chamber 3 through the bottom-side port 13a and the inside of the first cushion ring 50, the piston rod 20 and the piston 30 move in a direction that contracts the rod-side chamber 2, and the hydraulic cylinder 100 extends. At this time, the hydraulic oil in the rod-side chamber 2 is discharged to the tank through the passage 12b and the head-side port 12c.

[0030] Near the stroke end of the piston rod 20 in the extension direction, the second cushion ring 80 enters the passage 12b. With the second cushion ring 80 in the passage 12b, the flow path cross section of the passage 12b is narrowed by the second cushion ring 80, reducing the flow rate of hydraulic oil flowing from the rod-side chamber 2 to the passage 12b and increasing the pressure in the rod-side chamber 2. As a result, the piston rod 20 decelerates. In this way, a cushioning effect is produced near the stroke end of the piston rod 20 in the extension direction.

[0031] Furthermore, when hydraulic oil is supplied from the hydraulic power source through the passage 12b and the head-side port 12c to the rod-side chamber 2, the piston rod 20 and the piston 30 move in a direction that reduces the size of the anti-rod-side chamber 3, and the hydraulic cylinder 100 contracts. At this time, the hydraulic oil in the anti-rod-side chamber 3 is discharged to a tank (not shown) through the bottom-side port 13a and the first cushion ring 50.

[0032] Near the stroke end of the piston rod 20 in the retraction direction, the cushion portion 24 enters the first cushion ring 50. When the cushion portion 24 enters the first cushion ring 50, the cross section of the flow path inside the first cushion ring 50 is narrowed by the cushion portion 24, so the flow rate of hydraulic oil flowing from the anti-rod-side chamber 3 into the first cushion ring 50 decreases and the pressure in the anti-rod-side chamber 3 increases. As a result, the piston rod 20 decelerates. In this way, a cushioning effect is generated near the stroke end of the piston rod 20 in the retraction direction.

[0033] Next, the configuration of the receiving portion 13b of the cylinder bottom 13 will be described in detail.

[0034] 1 and 2, a first cushion ring 50 for decelerating the piston rod 20 near the stroke end is attached to the receiving portion 13b. An annular groove 13c is provided on the inner peripheral surface of the receiving portion 13b, and a snap ring 70 is provided in the annular groove 13c to engage with the outer peripheral surface of the first cushion ring 50 and prevent the first cushion ring 50 from falling off. The first cushion ring 50 is pressed in while being rotated by a jig 60 (see FIGS. 4 and 5) and attached to the receiving portion 13b.

[0035] 3, the first cushion ring 50 is cylindrical and made of a metal such as copper. The first cushion ring 50 has an outer diameter that is substantially the same as the inner diameter of the receiving portion 13b or slightly larger than the inner diameter of the receiving portion 13b to an extent that the first cushion ring 50 can be inserted into the receiving portion 13b, and an inner diameter that is larger than the outer diameter of the cushion portion 24 of the piston rod 20. The first cushion ring 50 has a cylindrical main body portion 51, an annular groove 52 provided on the outer peripheral surface of the main body portion 51 and capable of accommodating part of the snap ring 70, a tapered portion 54 as an inclined portion formed on the outer peripheral surface of the main body portion 51 on one end portion 53 side, and a groove 56 formed on the other end portion 55 as a transmission portion to which a rotational force for attachment to the receiving portion 13b is transmitted.

[0036] The annular groove 52 is provided to accommodate the snap ring 70 together with the annular groove 13c of the receiving portion 13b when the first cushion ring 50 is attached to the receiving portion 13b. The tapered portion 54 is provided to make it easier to attach the first cushion ring 50 to the receiving portion 13b, and is formed so that its outer diameter gradually decreases toward the one end 53. Note that the first cushion ring 50 may have, as the inclined portion, a curved portion formed so that its outer diameter gradually decreases toward the one end 53, instead of the tapered portion 54. The grooves 56 are engaged with the jig 60, and are formed to open at the other end 55, with two grooves 56 provided at positions facing each other. The grooves 56 penetrate the main body portion 51 in the radial direction.

[0037] The snap ring 70 is made of metal and is accommodated across the annular groove 13c of the receiving portion 13b and the annular groove 52 of the first cushion ring 50. The snap ring 70 is formed so that its inner diameter is smaller than the outer diameter of the main body portion 51 of the first cushion ring 50. The diameter of the snap ring 70 can be expanded by applying a force from the inner periphery toward the outer periphery.

[0038] 4 and 5 , the jig 60 for attaching the first cushion ring 50 to the receiving portion 13b is a rod-shaped member made of, for example, metal. The jig 60 has a gripping portion 61 that is gripped during attachment, a flange portion 62 provided at the end of the gripping portion 61, a sliding portion 63 that protrudes in the axial direction from the flange portion 62 and comes into sliding contact with the inner circumferential surface of the first cushion ring 50, and a hook portion 64 that protrudes in the axial direction from the flange portion 62 and engages circumferentially with the groove 56 of the first cushion ring 50.

[0039] The grip portion 61 is formed in a rod shape. The flange portion 62 is formed to have a diameter larger than the outer diameter of the main body portion 51 of the first cushion ring 50. The sliding contact portion 63 is cylindrical, and is formed so that its axial length is approximately the same as the axial length of the first cushion ring 50 and its outer diameter is approximately the same as the inner diameter of the first cushion ring 50. This allows the sliding contact portion 63 to be inserted into the first cushion ring 50, and when the sliding contact portion 63 is inserted into the first cushion ring 50, the outer peripheral surface of the sliding contact portion 63 comes into contact with the inner peripheral surface of the first cushion ring 50. The hook portion 64 is provided at a position corresponding to the groove 56 of the first cushion ring 50, and is formed so that its circumferential width is approximately the same as the circumferential width of the groove 56.

[0040] When assembling the hydraulic cylinder 100, the jig 60 is engaged with the first cushion ring 50, and the first cushion ring 50 is then rotated and pushed into the receiving portion 13b of the cylinder bottom 13 via the jig 60 to install it.

[0041] Next, a method for attaching the first cushion ring 50 to the receiving portion 13b will be described in detail, mainly with reference to FIG.

[0042] The first cushion ring 50 is attached to the cylinder bottom 13 before manufacturing the cylinder tube 10. Specifically, the first cushion ring 50 is attached to the receiving portion 13b of the cylinder bottom 13 before the cylinder bottom 13 is joined to the main body portion 11.

[0043] First, the snap ring 70 is inserted into the receiving portion 13b, and a portion of the snap ring 70 is accommodated in the annular groove 13c. Then, the jig 60 is engaged with the first cushion ring 50. Specifically, the sliding contact portion 63 of the jig 60 is inserted into the first cushion ring 50, the flange portion 62 of the jig 60 is brought into contact with the other end portion 55 of the first cushion ring 50, and the hook portion 64 of the jig 60 is accommodated in the groove 56 of the first cushion ring 50, and the hook portion 64 and the groove 56 are engaged in the circumferential direction.

[0044] Then, using the jig 60 to which the first cushion ring 50 is locked, the first cushion ring 50 is inserted from the tapered portion 54 into the receiving portion 13b and the inner circumferential surface of the snap ring 70 while being rotated. As the first cushion ring 50 is inserted, the snap ring 70 expands along the tapered portion 54 while remaining housed in the annular groove 13c, and slides on the outer circumferential surface of the main body portion 51. As the snap ring 70 expands along the tapered portion 54, the first cushion ring 50 receives an inward force from the snap ring 70. However, because the sliding contact portion 63 of the jig 60 is inserted into the first cushion ring 50, the first cushion ring 50 is prevented from being deformed inward by the force from the snap ring 70. When the flange portion 62 of the jig 60 contacts the open end 13d of the receiving portion 13b, the radial positions of the annular groove 13c and the annular groove 52 of the first cushion ring 50 overlap, and the snap ring 70 is housed across both the annular groove 13c and the annular groove 52. As a result, the first cushion ring 50 is supported by the receiving portion 13b via the snap ring 70, and the attachment of the first cushion ring 50 to the receiving portion 13b is completed.

[0045] In such a hydraulic cylinder, the first cushion ring is inserted by sliding along the inner circumferential surface of the snap ring, which inhibits insertion of the first cushion ring into the receiving portion. If the angle of the tapered portion of the first cushion ring is reduced, the snap ring is more likely to expand, allowing the first cushion ring to be inserted with less force and facilitating installation of the first cushion ring. However, the tapered portion becomes longer in the axial direction, resulting in a longer cushion ring, reducing the design freedom of the hydraulic cylinder. Conversely, if the angle of the tapered portion of the first cushion ring is increased, the axial length of the tapered portion becomes shorter, resulting in a shorter first cushion ring. This increases the design freedom of the hydraulic cylinder, but requires a greater force to insert the cushion ring, making installation of the first cushion ring more difficult. As such, it is difficult to achieve both the design freedom of the hydraulic cylinder and the ease of installation of the first cushion ring.

[0046] In the hydraulic cylinder 100 according to this embodiment, as described above, the first cushion ring 50 is attached to the receiving portion 13b from the tapered portion 54 by being rotated and pressed into the receiving portion 13b via the jig 60. In other words, the rotational force is transmitted to the groove 56, and the first cushion ring 50 is attached to the receiving portion 13b from the tapered portion 54. As a result, a force is applied to the first cushion ring 50 not only in the insertion direction but also in the rotational direction during attachment, which makes the snap ring 70 more likely to expand and makes attachment easier than when the first cushion ring 50 is simply inserted axially into the receiving portion 13b. Specifically, the first cushion ring 50 can be inserted into the receiving portion 13b with less axial force than when the first cushion ring 50 is simply inserted axially into the receiving portion 13b. Therefore, even if the angle of the tapered portion 54 of the first cushion ring 50 is increased and the axial length of the tapered portion 54 is shortened, the first cushion ring 50 can be easily attached. This improves the design freedom of the hydraulic cylinder 100 and the attachability of the first cushion ring 50.

[0047] Furthermore, because the first cushion ring 50 is attached to the receiving portion 13b while being rotated, the angle of the tapered portion 54 relative to the snap ring 70 during insertion is relatively smaller than when the first cushion ring 50 is simply inserted axially into the receiving portion 13b. This makes it easier for the snap ring 70 to expand, and the first cushion ring 50 can be attached to the receiving portion 13b more easily.

[0048] Furthermore, because the snap ring 70 easily expands, when the first cushion ring 50 is attached to the receiving portion 13b, the snap ring 70 slides over the tapered portion 54 of the first cushion ring 50, preventing the snap ring 70 from falling out of the annular groove 13c and becoming caught between the receiving portion 13b and the snap ring 70. If "galling" were to occur in the receiving portion 13b of the cylinder bottom 13, it would be difficult to confirm visually or otherwise. However, in this embodiment, as described above, it is possible to prevent the occurrence of "galling" in the receiving portion 13b of the cylinder bottom 13, which is difficult to confirm.

[0049] Furthermore, in this embodiment, as described above, the first cushion ring 50 can be inserted into the receiving portion 13b with a smaller axial force than when simply inserting the first cushion ring 50 into the receiving portion 13b in the axial direction. This makes it possible to manually insert the jig 60 while rotating it. If the snap ring 70 is about to fall off from the annular groove 13c of the receiving portion 13b during installation of the first cushion ring 50, the axial force required to insert the jig 60 increases, making the insertion operation of the jig 60 difficult. Therefore, if the snap ring 70 is about to fall off from the annular groove 13c when manually installing the first cushion ring 50 using the jig 60, the insertion operation of the jig 60 becomes difficult, allowing the operator to detect the defect himself. This allows the operator to stop installation of the first cushion ring 50 and investigate and eliminate the cause of the improper installation of the first cushion ring 50 before galling of the snap ring 70 occurs and the hydraulic cylinder 100 becomes defective. Specifically, the dimensions of the first cushion ring 50 and the like can be checked and re-machined, and foreign matter such as burrs can be confirmed and removed. Note that the attachment of the first cushion ring 50 is not limited to being performed manually using the jig 60, and the jig 60 may be inserted while being rotated using a press or the like.

[0050] Furthermore, in this embodiment, the rotational force is transmitted to the groove 56 of the first cushion ring 50 by the jig 60, so that the rotational force is transmitted to the first cushion ring 50 more reliably.

[0051] According to the present embodiment described above, the following advantageous effects are achieved.

[0052] The first cushion ring 50 is attached by entering the receiving portion 13b from the tapered portion 54 as a rotational force is transmitted to the groove 56, which makes it easier for the snap ring 70 to expand, making attachment easier than when the first cushion ring 50 is simply inserted into the receiving portion 13b in the axial direction. Therefore, even if the angle of the tapered portion 54 of the first cushion ring 50 is increased and the axial length of the tapered portion 54 is shortened, the first cushion ring 50 can be attached more easily than when the first cushion ring 50 is simply inserted into the receiving portion 13b in the axial direction. This improves the degree of freedom in designing the hydraulic cylinder 100 and the ease of attachment of the first cushion ring 50.

[0053] Because the first cushion ring 50 is attached to the receiving portion 13b while rotating, the angle of the tapered portion 54 relative to the snap ring 70 during insertion is relatively smaller than when the first cushion ring 50 is simply inserted in the axial direction of the receiving portion 13b. This makes it easier for the snap ring 70 to expand, making it possible to attach the first cushion ring 50 to the receiving portion 13b more easily.

[0054] In the hydraulic cylinder 100, when the first cushion ring 50 is attached, the snap ring 70 tends to expand, making it difficult for the snap ring 70 to fall off from the annular groove 13c of the receiving portion 13b, and preventing the snap ring 70 from becoming seized.

[0055] Because the first cushion ring 50 can be attached manually using the jig 60, even if galling of the snap ring 70 is about to occur, the operator can sense this by the fact that the insertion operation of the jig 60 becomes heavy. This allows the operator to stop attaching the first cushion ring 50 and investigate and eliminate the cause of the first cushion ring 50 not being attached properly before galling of the snap ring 70 occurs and the hydraulic cylinder 100 becomes defective.

[0056] Since the rotational force is transmitted to the groove 56 of the first cushion ring 50 by the jig 60, the rotational force is transmitted to the first cushion ring 50 more reliably.

[0057] Next, a modification of this embodiment will be described.

[0058] <Variation 1> In the above embodiment, a groove 56 is formed in the other end 55 of the first cushion ring 50 as a transmission portion through which a rotational force is transmitted, and the groove 56 and the hook portion 64 of the jig 60 engage circumferentially. However, the shape of the transmission portion is not limited to a groove, and any configuration is possible as long as the jig 60 is engaged with the first cushion ring 50 and a rotational force is transmitted from the jig 60 to the first cushion ring 50. For example, spike portions with an uneven shape may be provided in the other end 55 as a transmission portion, and the hook portion 64 of the jig 60 may have a shape corresponding to the spike portion. Furthermore, instead of the hook portion 64, a member with a high friction coefficient, such as an elastic member, may be provided on the end surface of the flange portion 62 that faces the first cushion ring 50, and the jig 60 may be engaged with the first cushion ring 50 by the frictional force of the elastic member. In this case, the transmission portion of the first cushion ring 50 is the contact surface of the other end 55 with the elastic member, etc.

[0059] <Variation 2> In the above embodiment, the cushion portion 24 is provided on the piston rod 20. However, the cushion portion 24 may also be provided on the piston 30. That is, the cushion portion 24 may be provided on the moving member 40 constituted by the piston rod 20 and the piston 30. Specifically, the piston 30 may be provided so as to cover the end of the piston rod 20, and the cushion portion 24 may be provided on the piston 30 so as to protrude toward the receiving portion 13b, and the cushion portion 24 may enter the receiving portion 13b. In other words, the cylinder bottom 13 may be provided with a receiving portion 13b that allows the moving member 40 to enter near the stroke end of the moving member 40. Even with this configuration, the same effects as those of this embodiment can be achieved.

[0060] <Variation 3> In the above embodiment, the receiving portion 13b is provided on the cylinder bottom 13. However, the receiving portion 13b may be provided on the piston rod 20. In this case, the receiving portion 13b is provided so as to open on the end face of the piston rod 20 that faces the cylinder bottom 13, and the cushion portion 24 that enters the receiving portion 13b is provided so as to protrude from the cylinder bottom 13 toward the receiving portion 13b. Even with this configuration, the same effects as in this embodiment can be achieved.

[0061] <Variation 4> In the above embodiment, the receiving portion 13b is provided on the cylinder bottom 13. However, the receiving portion 13b may also be provided on the piston 30. Specifically, the piston 30 may be provided so as to cover the end of the piston rod 20, and the receiving portion 13b may be provided so as to open on the end face of the piston 30 that faces the cylinder bottom 13. In other words, to summarize Modifications 3 and 4, the moving member 40 may be provided with a receiving portion 13b that allows the cushion portion 24 provided on the cylinder bottom 13 near the stroke end of the moving member 40 to enter. Even with this configuration, the same effects as this embodiment can be achieved.

[0062] <Variation 5> In the above embodiment, near the stroke end of the piston rod 20 in the extension direction, the second cushion ring 80 attached to the intermediate portion 22 of the piston rod 20 enters the passage 12b, thereby providing a cushioning effect. However, instead of the second cushion ring 80, a cushion ring similar to the first cushion ring 50 may be provided in the passage 12b, and the intermediate portion 22 of the piston rod 20 may enter the cushion ring to provide a cushioning effect. In other words, the first cushion ring 50 may provide a cushioning effect near the stroke end of the piston rod 20 in the extension direction. In this case, the receiving portion 13b, the annular groove 13c, and the snap ring 70 are provided on the inner circumferential surface of the cylinder head 12. Furthermore, the intermediate portion 22 of the piston rod 20 corresponds to the cushion portion 24 that enters the receiving portion 13b, and the intermediate portion 22 is formed to have a larger diameter than the rod main body 21. Even with this configuration, the same effects as those of the present embodiment can be achieved.

[0063] To summarize the above embodiment and variants 2 to 5, the hydraulic cylinder 100 may be configured to include a receiving portion 13b provided on one of the cylinder tube 10 and the movable member 40, which allows the other to enter near the stroke end of the movable member 40, and a first cushion ring 50 attached to the receiving portion 13b and which decelerates the movable member 40 near the stroke end.

[0064] The configuration, operation, and effects of the embodiment of the present invention configured as above will be described below.

[0065] A hydraulic cylinder 100 as a fluid pressure cylinder includes a cylinder tube 10, a movable member 40 slidably inserted into the cylinder tube 10, a receiving portion 13b provided on one of the cylinder tube 10 and the movable member 40 to allow the other to enter near the stroke end of the movable member 40, a first cushion ring 50 attached to the receiving portion 13b for decelerating the movable member 40 near the stroke end, and a snap ring 70 provided on the inner peripheral surface of the receiving portion 13b and engaging with the outer peripheral surface of the first cushion ring 50 to prevent the first cushion ring 50 from falling off, and the first cushion ring 50 has a tapered portion 54 as an inclined portion formed on the outer peripheral surface of one end 53, and a groove 56 as a transmission portion to transmit a rotational force for attaching the first cushion ring 50 from the tapered portion 54 to the receiving portion 13b.

[0066] In this configuration, a rotational force is transmitted to the groove 56, and the first cushion ring 50 is attached to the receiving portion 13b of the cylinder tube 10 or the moving member 40 through the tapered portion 54. As a result, a force is applied to the first cushion ring 50 not only in the insertion direction but also in the rotational direction during attachment, which makes it easier for the snap ring 70 to expand and for the first cushion ring 50 to be attached. Therefore, even if the angle of the tapered portion 54 is increased and the axial length of the tapered portion 54 is shortened, the first cushion ring 50 can be easily attached. This improves the degree of freedom in designing the hydraulic cylinder 100 and the ease of attaching the first cushion ring 50.

[0067] The transmission portion of the first cushion ring 50 is a groove 56 formed in the other end portion 55 of the first cushion ring 50 .

[0068] In this configuration, the rotational force is more reliably transmitted to the first cushion ring 50 by the grooves 56 .

[0069] The cylinder tube 10 also has a cylindrical main body 11, a cylinder head 12 as a head member that closes the opening at one end of the main body 11 and through which the movable member 40 is inserted, and a cylinder bottom 13 as a bottom member that closes the opening at the other end of the main body 11, and the receiving portion 13b is provided on one of the cylinder bottom 13 and the movable member 40.

[0070] In this configuration, in a hydraulic cylinder 100 equipped with a first cushion ring 50 for decelerating the moving member 40 at the stroke end in the direction in which the moving member 40 contracts, the degree of freedom in designing the hydraulic cylinder 100 and the ease of mounting of the first cushion ring 50 can be improved.

[0071] The hydraulic cylinder 100 as a fluid pressure cylinder also includes a cylinder tube 10, a movable member 40 slidably inserted into the cylinder tube 10, a receiving portion 13b provided on one of the cylinder tube 10 and the movable member 40 to allow the other to enter near the stroke end of the movable member 40, a first cushion ring 50 attached to the receiving portion 13b for decelerating the movable member 40 near the stroke end, and a snap ring 70 provided on the inner peripheral surface of the receiving portion 13b and engaging with the outer peripheral surface of the first cushion ring 50 to prevent the first cushion ring 50 from falling off, the first cushion ring 50 having a tapered portion 54 formed on the outer peripheral surface of one end 53. A manufacturing method for the hydraulic cylinder 100 as a fluid pressure cylinder includes engaging a jig 60 with the first cushion ring 50, and rotating and pushing the first cushion ring 50 through the jig 60 to attach it to the receiving portion 13b via the tapered portion 54.

[0072] In this configuration, the first cushion ring 50 is pushed in while being rotated via the jig 60, and is attached to the receiving portion 13b of the cylinder tube 10 or the moving member 40 from the tapered portion 54. As a result, a force is applied to the first cushion ring 50 not only in the insertion direction but also in the rotational direction during attachment, which makes it easier for the snap ring 70 to expand and for the first cushion ring 50 to be attached. Therefore, even if the angle of the tapered portion 54 is increased and the axial length of the tapered portion 54 is shortened, the first cushion ring 50 can be easily attached.

[0073] The jig 60 also has a hook portion 64 that engages with a groove 56 formed in the other end portion 55 of the first cushion ring 50 in the circumferential direction.

[0074] In this configuration, the hook portion 64 of the jig 60 engages with the groove 56 of the first cushion ring 50 , thereby allowing the jig 60 to be securely locked by the first cushion ring 50 .

[0075] Although the embodiments of the present invention have been described above, the above embodiments merely illustrate some of the application examples of the present invention, and it is not intended that the technical scope of the present invention be limited to the specific configurations of the above embodiments. [Explanation of symbols]

[0076] 10 Cylinder tube, 11 Main body, 12 Cylinder head (head member), 13 Cylinder bottom (bottom member), 40 Moving member, 50 First cushion ring (cushion ring), 53 One end, 54 Tapered portion (inclined portion), 55 Other end, 56 Groove (transmission portion), 60 Jig, 64 Hook portion, 70 Snap ring, 100 Hydraulic cylinder (fluid pressure cylinder)

Claims

1. A cylinder tube; a moving member slidably inserted into the cylinder tube; a receiving portion provided on one of the cylinder tube and the moving member, the receiving portion allowing the other to enter near a stroke end of the moving member; a cushion ring attached to the receiving portion for decelerating the moving member near the stroke end; a snap ring provided in a first annular groove provided on an inner peripheral surface of the receiving portion, the snap ring engaging with an outer peripheral surface of the cushion ring to prevent the cushion ring from falling off, The cushion ring is an inclined portion formed on the outer peripheral surface of one end portion; a transmission portion to which a rotational force is transmitted for attaching the cushion ring from the inclined portion to the receiving portion; a second annular groove provided on the outer peripheral surface and capable of accommodating a portion of the snap ring, The fluid pressure cylinder, characterized in that the snap ring is accommodated across the first annular groove of the receiving portion and the second annular groove of the cushion ring.

2. A cylinder tube, a moving member slidably inserted into the cylinder tube; a receiving portion provided on one of the cylinder tube and the moving member, the receiving portion allowing the other to enter near a stroke end of the moving member; a cushion ring attached to the receiving portion for decelerating the moving member near the stroke end; a snap ring provided on an inner peripheral surface of the receiving portion and engaging with an outer peripheral surface of the cushion ring to prevent the cushion ring from falling off, The cushion ring is an inclined portion formed on the outer peripheral surface of one end portion; a transmission portion to which a rotational force is transmitted for attaching the cushion ring to the receiving portion from the inclined portion, 10. A fluid pressure cylinder, comprising: a cushion ring having a first end and a second end; a cushion ring having a second end; a cushion ring having a second end;

3. 3. The fluid pressure cylinder according to claim 1 or 2, The cylinder tube is A cylindrical main body portion; a head member that closes an opening at one end of the main body portion and through which the moving member is inserted; a bottom member that closes an opening at the other end of the main body, The fluid pressure cylinder, wherein the receiving portion is provided on one of the bottom member and the moving member.

4. a receiving portion provided on one of the cylinder tube and the moving member, the receiving portion allowing the other to enter the moving member near a stroke end of the moving member; a cushion ring attached to the receiving portion for decelerating the moving member near the stroke end; and a snap ring provided on an inner peripheral surface of the receiving portion for engaging with an outer peripheral surface of the cushion ring to prevent the cushion ring from falling off, the cushion ring having an inclined portion formed on an outer peripheral surface of one end thereof, A method of manufacturing a fluid pressure cylinder, comprising: engaging a jig with the cushion ring; and rotating and pushing the cushion ring through the jig to attach it to the receiving portion from the inclined portion.

5. 5. A method for manufacturing a fluid pressure cylinder according to claim 4, comprising the steps of: a jig having a hook portion that circumferentially engages with a groove formed in the other end of the cushion ring;

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