Rotary joint

Abstract

To provide a rotary joint which enables improvement of maintainability of a stopper unit.SOLUTION: Each of a first rotary joint 31, a second rotary joint, and a third rotary joint has, at a peripheral wall 42, stopper units 70. The stopper unit 70 is inserted into a peripheral wall hole 42a. The stopper unit 70 has a stopper 71, a unit forming member 72, a first buffer member 73, a second buffer member 74, a lid member 75, and a mark member 76. The first buffer member 73 is housed in the peripheral wall hole 42a. The stopper unit 70 restricts rotation of a rotary member 50 relative to a fixing member 40 by engagement between a stopper engagement part 711 protruding from the first buffer member 73 and a rotary engagement part 55.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a rotary joint. [Background technology]

[0002] In a device having two members that rotate relative to one another, one member is connected to the other member via a rotary joint. The rotary joint has a fixed member and a rotary member rotatably attached to the fixed member. The rotary member is connected to one member, and the fixed member is connected to the other member. The rotary joint connects the one member and the other member so that they can rotate relative to one another. For example, as disclosed in Patent Document 1, in a rotary joint, the fixed member is disposed inside the rotary member and is disposed at a distance from the outer circumferential surface of the rotary member. The rotary member is rotatable inside the fixed member while being spaced apart from the inner circumferential surface of the fixed member.

[0003] Generally, a rotary joint has a stopper and a rotational engagement portion to define the rotation range of the rotating member. The stopper is threadedly engaged with the fixed member and protrudes from the inner peripheral surface of the fixed member toward the rotating member. The rotational engagement portion is provided on the outer peripheral surface of the rotating member. The rotational engagement portion engages with the stopper in the rotational direction of the rotating member, thereby defining the rotational range of the rotating member. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-062943 Summary of the Invention [Problem to be solved by the invention]

[0005] In a rotary joint, it is desirable to reduce the impact generated at the stopper when the rotational engagement portion engages with the stopper. For example, in order to absorb the impact generated at the stopper, it is conceivable to provide a buffer member at the portion of the stopper that engages with the rotational engagement portion. However, the buffer member wears out and undergoes plastic deformation as it repeatedly absorbs the impact generated at the stopper due to engagement with the rotational engagement portion. The wear and plastic deformation of the buffer member leads to a decrease in the impact absorption performance of the buffer member. For this reason, rotary joints require maintenance work, including replacement of the buffer member. Therefore, it is desirable to improve the maintainability of the stopper and buffer member in rotary joints. [Means for solving the problem]

[0006] A rotary joint for solving the above problem includes a rotary member having a rotational engagement portion on its outer circumferential surface, a fixed member consisting of a bottom wall supporting the rotary member and a peripheral wall extending from the edge of the bottom wall and surrounding the rotary member and the rotational engagement portion, and a stopper provided on the peripheral wall, the stopper having a stopper engagement portion that engages with the rotational engagement portion in the circumferential direction of the rotary member, and a shaft portion that extends from the rotary member in a direction toward the fixed member and has a first shaft end where the stopper engagement portion is provided and a second shaft end in the axial direction, the fixed member accommodating the rotary member in a rotation chamber defined by the bottom wall and the peripheral wall, the rotational engagement portion being rotatable along the peripheral wall, and the engagement between the stopper engagement portion and the rotational engagement portion defining a rotation range of the rotary member in the rotation chamber. the stopper unit includes a stopper unit that includes the stopper and is inserted into a peripheral wall hole that opens on the outer peripheral wall surface and the inner peripheral wall surface of the peripheral wall, the stopper unit having a buffer member through which the shaft portion passes and from which the stopper engagement portion protrudes, and that is housed in the peripheral wall hole; a unit forming member that has a flange portion that faces the buffer member in the axial direction and a direction perpendicular to the axial direction, that is provided continuous with the second shaft end in the axial direction, and that is inserted inside the buffer member; and a cover member that is provided closer to the outer peripheral wall surface than the buffer member in the axial direction, and that is fixed to the peripheral wall, the buffer member being interposed between the shaft portion, the flange portion, and the peripheral wall, and the buffer member being held by the peripheral wall by the cover member.

[0007] In the above rotary joint, the cover member defines a cover through hole that penetrates in the axial direction, the unit forming member has a first connecting end that connects to the second shaft end and has the flange portion, and a second connecting end that penetrates the cover through hole and protrudes from the cover member, the second connecting end is provided with a marker member that interlocks with the stopper, the cover through hole is an elongated hole whose long axis extends in the circumferential direction, and the outer diameter of the second connecting end of the unit forming member may be smaller than an opening width in the direction in which the long axis extends.

[0008] In the above rotary joint, when the buffer member is a first buffer member, the stopper unit may have a second buffer member, the second connection end of the unit forming member may penetrate the second buffer member, and the second buffer member may be sandwiched between the cover member and the flange portion in the axial direction.

[0009] In the above rotary joint, the first buffer member may have a buffer outer peripheral surface facing the peripheral wall, the buffer outer peripheral surface having an inclined surface along which the outer diameter of the first buffer member increases in a direction from the first shaft end toward the second shaft end, and the peripheral wall may have a hole-defining surface that engages with the buffer outer peripheral surface and defines the peripheral wall hole.

[0010] In the above rotary joint, the second buffer member may be spaced apart from the first buffer member in the axial direction. In the above rotary joint, the rotational engagement portion may be formed of a material harder than that of the stopper engagement portion. [Effects of the Invention]

[0011] According to the present invention, the maintainability of the stopper unit can be improved. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a schematic diagram showing an arm-type assistive device. [Figure 2] FIG. 2 is a schematic diagram showing an arm-type assist device. [Figure 3] FIG. 3 is an exploded perspective view showing the first rotary joint. [Figure 4] FIG. 4 is a perspective view showing the first rotary joint. [Figure 5] FIG. 5 is an exploded perspective view showing the stopper unit. [Figure 6] FIG. 6 is a cross-sectional view showing the first rotary joint. [Figure 7]FIG. 7 is a cross-sectional view showing the stopper unit. [Figure 8] FIG. 8 is a cross-sectional view showing the first rotary joint. [Figure 9] FIG. 9 is a diagram showing the cover member and the mark member. [Figure 10] FIG. 10 is a cross-sectional view showing the stopper unit. [Figure 11] FIG. 11 is a diagram showing the cover member and the mark member. [Figure 12] FIG. 12 is a cross-sectional view showing the stopper unit. DETAILED DESCRIPTION OF THE INVENTION

[0013] An embodiment of the rotary joint will now be described with reference to Figures 1 to 12. In this embodiment, the rotary joint is mounted on an arm-type assistive device. <Arm-type assistive device> 1 and 2, the arm-type assist device 100 has a base 10, a first arm 11, a second arm 12, a first support portion 13, a second support portion 14, and a load holding portion 15. The arm-type assist device 100 has an air supply source 21 and a control device 22. The arm-type assist device 100 also has first to third rotary joints 31 to 33 as rotary joints.

[0014] The air supply source 21 supplies compressed air to the arm-type assistive device 100. The control device 22 controls the air supplied from the air supply source 21 to the arm-type assistive device 100. The control device 22 also calculates the pressure of the air to be supplied to the arm-type assistive device 100 in order to balance the weight of the load suspended from the arm-type assistive device 100.

[0015] The base 10 is columnar. However, the base 10 does not have to be columnar. For example, the base 10 may be a low platform. In other words, the shape of the base 10 is arbitrary. The first support portion 13 has a columnar shape extending in the vertical direction Z. The first support portion 13 is provided at the upper end of the base 10. The first support portion 13 rotates about a first vertical axis Z1 extending in the vertical direction Z. In other words, the first support portion 13 is provided on the base 10 so as to be rotatable within a horizontal plane.

[0016] The first arm 11 is connected at a first end to a first support portion 13. The first arm 11 is capable of swinging in the vertical direction Z relative to the first support portion 13. The second support portion 14 is columnar and extends in the vertical direction Z. The second support portion 14 is connected to a second end of the first arm 11. The first arm 11 is capable of swinging in the vertical direction Z relative to the second support portion 14.

[0017] The first arm 11 incorporates an actuator 17. The actuator 17 is an air cylinder. The actuator 17 is connected to an air supply source 21 via a control device 22 and is driven by air supplied by the air supply source 21. The actuator 17 drives a parallelogram link H consisting of the first arm 11, the first support portion 13, and the second support portion 14. Specifically, when the first arm 11 swings in the vertical direction Z relative to the first support portion 13 as the control device 22 drives the actuator 17, the second support portion 14 moves in the vertical direction Z. At this time, as shown in FIG. 2 , the second support portion 14 moves in the vertical direction Z while maintaining its upper surface horizontal due to the parallelogram link H.

[0018] The second arm 12 is cylindrical and hollow, extending horizontally. The second arm 12 is provided on the upper surface of the second support portion 14. The second arm 12 is aligned with the second support portion 14 in the vertical direction Z at its first end. The second arm 12 rotates about a second vertical axis Z2 extending in the vertical direction Z. In other words, the second arm 12 is provided on the upper surface of the second support portion 14 so as to be rotatable within a horizontal plane.

[0019] The load holding portion 15 has a columnar shape extending in the vertical direction Z. The load holding portion 15 is provided on the second end side of the underside of the second arm 12. The load holding portion 15 rotates relative to the second arm 12 around a third vertical axis Z3 extending in the vertical direction Z. The load holding portion 15 has a pair of operating levers 15a. The load holding portion 15 has a hook-type suspending device 15b. For example, the hook-type suspending device 15b may be configured to suction-hold the load or to be held by a robot hand.

[0020] The arm-type assistive device 100 houses a plurality of cables (not shown) inside. The plurality of cables are, for example, pipes that connect to the air supply source 21 and supply air to the actuator 17.

[0021] <Rotational joint> 1, the first rotary joint 31 rotates about a first rotation axis L1, the second rotary joint 32 rotates about a second rotation axis L2, and the third rotary joint 33 rotates about a third rotation axis L3.

[0022] 3 and 4, first rotary joint 31 has a fixed member 40, a rotary member 50, a rotary connection member 56, a rotation restricting member 60, and a stopper unit 70. The following description of first rotary joint 31 also applies to second rotary joint 32 and third rotary joint 33.

[0023] <Fixing material> The fixing member 40 has a bottom wall 41 and a peripheral wall 42 . The bottom wall 41 is disk-shaped. In the thickness direction, the bottom wall 41 has a bottom wall lower surface 411 and a bottom wall upper surface 412. A bottom wall hole 41a is formed in the center of the bottom wall 41. The bottom wall hole 41a is open at both the bottom wall lower surface 411 and the bottom wall upper surface 412.

[0024] The peripheral wall 42 has a cylindrical shape with the first rotation axis L1 as its central axis. In other words, the peripheral wall 42 has a cylindrical shape with a thickness direction perpendicular to the first rotation axis L1. The peripheral wall 42 has a wall outer peripheral surface 421 and a wall inner peripheral surface 422.

[0025] A plurality of peripheral wall holes 42a are formed in the peripheral wall 42. Each peripheral wall hole 42a is defined by a hole defining surface 42c of the peripheral wall 42. Each peripheral wall hole 42a extends in the thickness direction of the peripheral wall 42 and opens at both the wall outer peripheral surface 421 and the wall inner peripheral surface 422. The plurality of peripheral wall holes 42a are formed at equal intervals in the circumferential direction of the peripheral wall 42. The peripheral wall holes 42a are formed at 12 locations in the peripheral wall 42. However, the number of peripheral wall holes 42a formed in the peripheral wall 42 is not limited to this.

[0026] As shown in FIG. 6, the hole-defining surface 42c is composed of a first demarcating surface 421c, a second demarcating surface 422c, and a demarcating inclined surface 423c. The first demarcating surface 421c is a portion of the hole-defining surface 42c that is closer to the wall inner circumferential surface 422 and connects to the wall inner circumferential surface 422. The demarcating inclined surface 423c is a portion of the hole-defining surface 42c that is closer to the wall outer circumferential surface 421 than the first demarcating surface 421c. The second demarcating surface 422c is a portion of the hole-defining surface 42c that is closer to the wall outer circumferential surface 421 than the demarcating inclined surface 423c and connects to the wall outer circumferential surface 421. The demarcating inclined surface 423c is inclined from the wall inner circumferential surface 422 toward the wall outer circumferential surface 421 so that the diameter of the peripheral wall hole 42a increases.

[0027] Pairs of fixing holes 42b are formed at multiple locations on the wall outer peripheral surface 421. The pairs of fixing holes 42b are formed in the peripheral wall 42 so as to sandwich each peripheral wall hole 42a in the circumferential direction of the peripheral wall 42. Each of the pair of fixing holes 42b extends in the axial direction of the peripheral wall hole 42a formed between the pair of fixing holes 42b. In other words, each of the pair of fixing holes 42b is parallel to the peripheral wall hole 42a formed between the pair of fixing holes 42b. An internal thread is formed on the inner surface defining each fixing hole 42b.

[0028] 3, the peripheral wall 42 is connected to the edge of the bottom wall 41 and extends in a direction from the bottom wall lower surface 411 toward the bottom wall upper surface 412. In other words, the peripheral wall 42 extends from the edge of the bottom wall 41. The thickness direction of the bottom wall 41 is a direction along the first rotation axis L1. In the fixed member 40, one end of the peripheral wall 42 in the direction along the first rotation axis L1 is covered by the peripheral wall 42 and the other end is open.

[0029] A rotation chamber 40a is formed in the first rotary joint 31. The rotation chamber 40a is defined by a bottom wall 41 and a peripheral wall 42. In other words, the rotation chamber 40a is defined by a bottom wall upper surface 412 and a wall inner peripheral surface 422.

[0030] <Rotating parts> The rotating member 50 is cylindrical with the first rotation axis L1 as its central axis. The rotating member 50 has a lower rotating surface 53 and an upper rotating surface 54 that are surfaces perpendicular to the first rotation axis L1. The rotating member 50 has an outer rotating surface 51 as its outer surface, and as shown in FIG. 6, has an inner rotating surface 52. The inner rotating surface 52 defines a through hole in the rotating member 50. The through hole defined by the inner rotating surface 52 opens at both the lower rotating surface 53 and the upper rotating surface 54.

[0031] 3 and 6, the rotating member 50 has a rotational engagement portion 55. The material of the rotational engagement portion 55 is, for example, iron, but the material of the rotational engagement portion 55 is not limited to iron. The rotational engagement portion 55 may be made of any material as long as it is harder than the material of the stopper engagement portion 711, which will be described later. The rotational engagement portion 55 is fixed to a portion of the rotating outer peripheral surface 51 in the circumferential direction. In other words, the rotating member 50 has the rotational engagement portion 55 on the rotating outer peripheral surface 51.

[0032] The rotational engagement portion 55 is block-shaped. The rotational engagement portion 55 has an engagement portion outer surface 55a in a direction perpendicular to the first rotation axis L1. The engagement portion outer surface 55a is curved so as to form a circle concentric with the rotational outer peripheral surface 51. The radius of curvature of the engagement portion outer surface 55a matches the inner radius of the peripheral wall 42. The rotational engagement portion 55 has a pair of engagement portion side surfaces 55c. The engagement portion side surfaces 55c are surfaces of the outer surface of the rotational engagement portion 55 that face the circumferential direction of the rotating member 50. Each engagement portion side surface 55c is recessed in a hemispherical shape in the circumferential direction of the rotating member 50.

[0033] As shown in Figure 3, the rotary connection member 56 is cylindrical with the first rotation axis L1 as its central axis. The rotary connection member 56 has a cylindrical tubular portion 56a, a rotary flange portion 56c extending beyond the outer peripheral surface of the tubular portion 56a, and a rotary connection inner peripheral surface 56b. The outer diameter of the tubular portion 56a is smaller than the outer diameter of the rotary flange portion 56c. The rotary connection inner peripheral surface 56b defines a through hole extending along the first rotation axis L1.

[0034] The rotary connection member 56 is coupled to the rotary member 50. The rotary connection member 56 is coupled to the rotary member 50 at an end of the cylindrical portion 56a that is different from the end where the rotary flange portion 56c is formed. The rotary connection member 56 is fixed to the upper rotary surface 54. Therefore, the rotary connection member 56 moves in conjunction with the rotary member 50. The rotary connection member 56 is coupled to the rotary member 50 so that a through hole defined by the rotary connection inner peripheral surface 56b and a through hole defined by the rotary inner peripheral surface 52 are in communication with and coaxial with each other. The through hole defined by the rotary connection inner peripheral surface 56b and the through hole defined by the rotary inner peripheral surface 52 form a first rotary connection hole 50a. The first rotary connection hole 50a extends along the first rotation axis L1 and penetrates the rotary member 50 and the rotary connection member 56.

[0035] <Rotation restriction member> The rotation restricting member 60 has a brake disc 61 and a rotary lid portion 62. The brake disc 61 is disk-shaped with its thickness direction aligned with the first rotation axis L1. The brake disc 61 has a through-hole formed therein that penetrates the brake disc 61 in its thickness direction.

[0036] The rotary lid portion 62 is cylindrical and has a central axis on the first rotation axis L1. The rotary lid portion 62 has a rotary lid inner peripheral surface 62b. The rotary lid inner peripheral surface 62b defines a through hole in the rotary lid portion 62 that extends in the axial direction.

[0037] The rotation restricting member 60 is formed by arranging a brake disc 61 and a rotary lid portion 62 in the direction in which the first rotation axis L1 extends. The rotary lid portion 62 is fixed to the brake disc 61 so that a through hole defined by the rotary lid inner peripheral surface 62b communicates with a through hole formed in the brake disc 61. The through hole of the brake disc 61 and the through hole of the rotary lid portion 62 form a second rotary connection hole 60a. The second rotary connection hole 60a penetrates the rotation restricting member 60 in the direction in which the first rotation axis L1 extends.

[0038] <Relationship between fixed member, rotating member, rotating connecting member, and rotation restricting member> 3 and 4, the fixed member 40 accommodates the rotary member 50 and the rotary connection member 56 in the rotary chamber 40a. The lower rotary surface 53 faces the bottom wall upper surface 412. In the first rotary joint 31, the bottom wall hole 41a and the first rotary connection hole 50a are in communication with each other.

[0039] 6, the rotating member 50 is housed in the rotating chamber 40a so that the outer rotating surface 51 and the outer engaging portion surface 55a are spaced apart from the wall inner peripheral surface 422. The peripheral wall 42 surrounds the rotating member 50 and the rotation engaging portion 55. More specifically, the rotating member 50 is housed in the rotating chamber 40a so as to be rotatable together with the rotation engaging portion 55 around the first rotation axis L1. The rotation engaging portion 55 is also rotatable along the wall inner peripheral surface 422.

[0040] The rotating member 50 is provided to the fixed member 40 via a bearing and a washer (not shown). The washer prevents the rotating member 50 from moving relative to the fixed member 40 in the direction of the first rotation axis L1.

[0041] 3 and 4, the rotation restricting member 60 is provided on the upper surface of the rotary connection member 56. The rotation restricting member 60 is provided on the upper surface of the rotary connection member 56 so that the first rotary connection hole 50a and the second rotary connection hole 60a are in communication with each other. The second rotary connection hole 60a is in communication with the bottom wall hole 41a via the first rotary connection hole 50a. The rotation restricting member 60 is rotatable together with the rotary member 50 and the rotary connection member 56.

[0042] A brake device (not shown) is provided on the rotation restricting member 60. The brake device is connected to the control device 22, and operates on the brake disc 61 of the rotation restricting member 60 based on a signal transmitted from the control device 22. In this way, the brake device restricts the rotation of the rotation restricting member 60 relative to the fixed member 40. In other words, the brake device restricts the rotation of the rotating member 50 and the rotary connection member 56 relative to the fixed member 40 via the rotation restricting member 60.

[0043] <Overall view of the stopper unit> 3 and 6, the first rotary joint 31 has two stopper units 70. The following describes one of the two stopper units 70 included in the first rotary joint 31, but the same description also applies to the other stopper unit 70.

[0044] 5 and 7, the stopper unit 70 has a stopper 71, a unit forming member 72, a first buffer member 73 as a buffer member, a second buffer member 74, a lid member 75, and a marker member 76. In other words, the stopper unit 70 includes the stopper 71. The stopper unit 70 has a unit bolt 91 and a pair of lid fixing bolts 92.

[0045] <Stopper> The stopper 71 has a cylindrical shape. The stopper 71 has a stopper engagement portion 711 on the first end side in the axial direction, and has a shaft portion 712 on the second end side of the stopper engagement portion 711. The stopper 71 has a stopper outer peripheral surface 71a.

[0046] The stopper engagement portion 711 is cylindrical with the axis of the stopper 71 as its central axis. The stopper engagement portion 711 has a stopper engagement portion outer surface 711a. The material of the stopper engagement portion 711 is, for example, stainless steel. The material of the stopper engagement portion 711 is not limited to this. The material of the stopper engagement portion 711 may be any material as long as it is softer than the material of the rotation engagement portion 55. In other words, the rotation engagement portion 55 is made of a material that is harder than the stopper engagement portion 711.

[0047] The shaft portion 712 is cylindrical with the axis of the stopper 71 as its central axis. In other words, the axial direction of the shaft portion 712 is the direction in which the axis of the stopper 71 extends. The shaft portion 712 has a first shaft end portion 712a at one end in the axial direction and a second shaft end portion 712b at the other end. The shaft portion 712 is connected to the stopper engagement portion 711 at the first shaft end portion 712a. In other words, the shaft portion 712 has the first shaft end portion 712a where the stopper engagement portion 711 is provided, and the second shaft end portion 712b in the axial direction.

[0048] A shaft insertion hole 712c is formed in the second shaft end portion 712b of the shaft portion 712. The shaft insertion hole 712c extends in the axial direction of the shaft portion 712. An internal thread is formed on the inner circumferential surface that defines the shaft insertion hole 712c.

[0049] The shaft portion 712 has a shaft outer peripheral surface 712d. The stopper outer peripheral surface 71a is composed of the stopper engagement portion outer surface 711a and the shaft outer peripheral surface 712d. The shaft portion 712 has a smaller outer diameter than the stopper engagement portion 711. In other words, the stopper 71 has the stopper outer peripheral surface 71a that becomes smaller from the first shaft end portion 712a to the second shaft end portion 712b.

[0050] <Unit forming parts> The unit forming member 72 is cylindrical. The unit forming member 72 has a unit outer peripheral surface 72a and a unit inner peripheral surface 72b. The unit inner peripheral surface 72b defines a unit insertion hole 72c. The unit forming member 72 has a first connecting end 72f at one end in the axial direction and a second connecting end 72g at the other end.

[0051] The unit forming member 72 has a flange portion 72d at the first connecting end 72f, and a unit base portion 72e located closer to the second connecting end 72g than the flange portion 72d. The unit forming member 72 is composed of the flange portion 72d and the unit base portion 72e. The flange portion 72d bulges out in the radial direction of the unit forming member 72 compared to the unit base portion 72e. In other words, the outer diameter of the flange portion 72d is larger than the outer diameter of the unit base portion 72e.

[0052] The flange portion 72d has a flange portion outer peripheral surface 721a. The unit base portion 72e has a unit base outer peripheral surface 722a. That is, the unit outer peripheral surface 72a is made up of the flange portion outer peripheral surface 721a and the unit base outer peripheral surface 722a.

[0053] As shown in FIG. 7, the unit inner circumferential surface 72b is composed of a first unit inner surface 721b and a second unit inner surface 722b. The first unit inner surface 721b is a portion of the unit inner circumferential surface 72b that is closer to the first connecting end 72f of the unit forming member 72. The second unit inner surface 722b is a portion of the unit inner circumferential surface 72b that is different from the first unit inner surface 721b. The diameter of the hole defined by the first unit inner surface 721b is larger than the diameter of the hole defined by the second unit inner surface 722b. In other words, the diameter of the unit insertion hole 72c increases from the first connecting end 72f toward the second connecting end 72g.

[0054] The outer diameter of the unit outer peripheral surface 72a at the flange portion 72d is larger than the outer diameter of the shaft portion 712. The diameter of the hole defined by the first unit inner surface 721b of the unit forming member 72 is slightly larger than the outer diameter of the shaft portion 712. The diameter of the hole defined by the second unit inner surface 722b of the unit forming member 72 is approximately the same as the diameter of the shaft portion insertion hole 712c.

[0055] <First cushioning member> As shown in Fig. 5, the first buffer member 73 is cylindrical. The first buffer member 73 is made of an elastic material, such as a rubber material. The first buffer member 73 has an outer buffer surface 73a and an inner buffer surface 73b. The inner buffer surface 73b defines a first buffer hole 73c.

[0056] As shown in FIGS. 6 and 7 , the buffer outer surface 73a is composed of a first buffer outer surface 731a, a second buffer outer surface 732a, and an inclined surface 733a. The first buffer outer surface 731a is a portion of the buffer outer surface 73a closer to the first end of the first buffer member 73 in the axial direction. The inclined surface 733a is a portion of the buffer outer surface 73a closer to the second end of the first buffer member 73 than the first buffer outer surface 731a. The second buffer outer surface 732a is a portion of the buffer outer surface 73a closer to the second end of the first buffer member 73 than the inclined surface 733a. In the first buffer member 73, the outer diameter of the second buffer outer surface 732a is larger than the outer diameter of the first buffer outer surface 731a. In the first buffer member 73, the outer diameter of the inclined surface 733a increases from the first end toward the second end. The inner diameter of the first buffering inner surface 731b of the first buffering member 73 is smaller than the outer diameter of the stopper engagement portion 711 and larger than the outer diameter of the first buffering outer surface 731a.

[0057] The buffer inner circumferential surface 73b is composed of a first buffer inner surface 731b and a second buffer inner surface 732b. The first buffer inner surface 731b is a portion of the buffer inner circumferential surface 73b that is closer to the first end of the first buffer member 73. The second buffer inner surface 732b is a portion of the buffer inner circumferential surface 73b that is closer to the second end of the first buffer member 73. The inner diameter of the second buffer inner surface 732b of the first buffer member 73 is larger than the inner diameter of the first buffer inner surface 731b. In other words, the hole diameter of the first buffer hole 73c increases from the first end to the second end.

[0058] The edge of the first buffer inner surface 731b on the second end side and the edge of the second buffer inner surface 732b on the first end side are connected by a buffer engagement surface 733b. The buffer engagement surface 733b is a surface that is perpendicular to the axis of the first buffer member 73 and faces in the direction from the first end to the second end of the first buffer member 73.

[0059] 5, the first buffer member 73 has an outer end surface 73d and an inner end surface 73e. The outer end surface 73d is a surface of the outer surface of the first buffer member 73 that connects to the second buffer outer surface 732a and the second buffer inner surface 732b at the second end. The outer end surface 73d is perpendicular to the axis of the first buffer member 73.

[0060] The inner end surface 73e is a surface that connects to the first buffer outer surface 731a and the first buffer inner surface 731b at the first end of the outer surface of the first buffer member 73. The inner end surface 73e is perpendicular to the axis of the first buffer member 73.

[0061] The inner diameter of the first buffering inner surface 731b of the first buffering member 73 is slightly larger than the outer diameter of the shaft portion 712. The inner diameter of the second buffering inner surface 732b is slightly larger than the outer diameter of the flange portion 72d. <Second cushioning member> The second buffer member 74 is disk-shaped. The second buffer member 74 is made of an elastic material. The elastic material is, for example, a rubber material. The second buffer member 74 has a first disk end face 74a and a second disk end face 74b in the thickness direction. The second buffer member 74 has a disk outer peripheral face 74c and a disk inner peripheral face 74d in a direction perpendicular to the thickness direction. The disk inner peripheral face 74d defines a second buffer hole 74e. The second buffer hole 74e opens at each of the first disk end face 74a and the second disk end face 74b.

[0062] The outer diameter of the second buffer member 74 is the same as the outer diameter at the second end of the first buffer member 73. The hole diameter of the second buffer hole 74e is larger than the outer diameter of the unit base portion 72e. <Cover parts> The lid member 75 is disk-shaped. In the thickness direction, the lid member 75 has a lid outer surface 75a, a lid inner surface 75b, and a lid hole-defining surface 75c. The lid hole-defining surface 75c defines a lid through-hole 75d. The lid through-hole 75d opens in both the lid outer surface 75a and the lid inner surface 75b. A pair of lid fastening holes 75e are formed in the lid member 75. Each of the pair of lid fastening holes 75e opens in both the lid outer surface 75a and the lid inner surface 75b. The lid through-hole 75d is elongated, with its major axis extending between the pair of lid fastening holes 75e.

[0063] The lid member 75 has a holding portion 75f, which is cylindrical and stands upright from the edge of the lid inner surface 75b. The opening width of the lid through-hole 75d in the minor axis direction is slightly larger than the outer diameter of the unit base 72e. The opening width of the lid through-hole 75d in the major axis direction is sufficiently larger than the outer diameter of the unit base 72e. The outer diameter of the second connection end 72g of the unit forming member 72 is smaller than the opening width of the lid through-hole 75d in the direction along the major axis. As shown in FIG. 7, the inner diameter of the holding portion 75f is slightly larger than the outer diameter of the second buffer member 74.

[0064] <Marking material> As shown in FIG. 5, the marker member 76 is disk-shaped. The marker member 76 is, for example, a washer. The marker member 76 has a first marker surface 76a and a second marker surface 76b in the thickness direction. A marker member hole 76c is formed in the marker member 76. The marker member hole 76c opens on each of the first marker surface 76a and the second marker surface 76b. The diameter of the marker member hole 76c matches the inner diameter of the unit base 72e.

[0065] <Stopper unit configuration> 5 and 7, the stopper unit 70 is formed by integrating a stopper 71, a unit forming member 72, a first buffer member 73, a second buffer member 74, a cover member 75, and a marker member 76 with a unit bolt 91. The unit bolt 91 has a bolt shank 91a at a first end and a bolt flange 91b at a second end. A male thread is formed on the bolt shank 91a.

[0066] The unit bolt 91 has a bolt shank 91a inserted into the shank insertion hole 712c, the unit insertion hole 72c, and the marker member hole 76c. The bolt shank 91a is threadedly engaged with the stopper 71. The bolt flange 91b is located opposite the second marker surface 76b and fixes the marker member 76 to the second connection end 72g of the unit forming member 72. Therefore, the unit bolt 91 tightens the unit forming member 72 and the marker member 76 together to the stopper 71.

[0067] In the stopper unit 70, the axis of the stopper 71 coincides with the axis of the unit forming member 72. The second end of the stopper 71 is inserted into the unit insertion hole 72c from the first connecting end 72f of the unit forming member 72. In other words, the stopper 71 has the shaft portion 712 inserted into the unit insertion hole 72c. In other words, the stopper 71 is connected to the unit forming member 72. The second unit inner surface 722b and the inner circumferential surface that defines the shaft portion insertion hole 712c are continuous in the axial direction of the stopper 71. The unit forming member 72 is provided to be continuous with the second shaft end portion 712b in the axial direction of the shaft portion 712.

[0068] In the stopper unit 70, the axis of the marker member 76 coincides with the axis of the unit forming member 72. The marker member 76 is provided at a position where the first marker surface 76a and the second connecting end 72g of the unit forming member 72 face each other. That is, the marker member 76 is provided at the second connecting end 72g. In other words, the unit forming member 72 is connected to the stopper 71 at one end and to the marker member 76 at the other end. The stopper 71 moves in conjunction with the unit forming member 72 and also in conjunction with the marker member 76. Therefore, the marker member 76, which moves in conjunction with the stopper 71, is provided at the second connecting end 72g.

[0069] In the stopper unit 70, the axis of the first buffer member 73 coincides with the axis of the stopper 71. The stopper 71 has a shaft portion 712 inserted into a first buffer hole 73c, with a stopper engagement portion 711 protruding from a first end of the first buffer member 73. The shaft portion outer surface 712d faces the buffer inner surface 73b. That is, the shaft portion 712 passes through the first buffer member 73, and the stopper engagement portion 711 protrudes. The buffer outer surface 73a has a first buffer outer surface 731a near the first axial end 712a and a second buffer outer surface 732a near the second axial end 712b. That is, the buffer outer surface 73a has an inclined surface 733a along which the outer diameter of the first buffer member 73 increases in the direction from the first axial end 712a to the second axial end 712b.

[0070] The shaft portion 712 has a second shaft end portion 712b protruding from a portion of the first buffer hole 73c defined by the first buffer inner surface 731b. The unit forming member 72 is inserted inside the first buffer member 73. The unit forming member 72 is provided on the second shaft end portion 712b so that the flange portion outer peripheral surface 721a faces the second buffer inner surface 732b and the first unit inner surface 721b faces the shaft portion outer peripheral surface 712d. That is, the flange portion 72d faces both the shaft portion outer peripheral surface 712d and the second buffer inner surface 732b in a direction perpendicular to the axis of the unit forming member 72. The flange portion 72d also faces the buffer engagement surface 733b in the axial direction of the unit forming member 72. That is, the flange portion 72d faces the first buffer member 73 in the axial direction of the shaft portion 712 and in a direction perpendicular to the axial direction. The shaft portion 712 slightly protrudes from the portion of the first buffer hole 73c defined by the first buffer inner surface 731b in the axial direction of the unit forming member 72.

[0071] The axis of the second buffer member 74 coincides with the axis of the first buffer member 73. The second buffer member 74 is located so that the first disk end face 74a faces the outer end face 73d of the first buffer member 73. The unit base 72e is inserted into the second buffer hole 74e. In other words, the unit base 72e penetrates the second buffer member 74. The inner diameter of the second buffer member 74 is larger than the outer diameter of the unit base 72e. In other words, the disk inner peripheral surface 74d surrounds the unit base 72e while being spaced apart from the unit base outer peripheral surface 722a.

[0072] A portion of the first disk end face 74a that is closer to the inside in the radial direction of the second buffer member 74 faces the flange portion 72d in the axial direction of the second buffer member 74. Furthermore, a portion of the first disk end face 74a that is closer to the outside in the radial direction of the second buffer member 74 faces the first buffer member 73 in the axial direction of the second buffer member 74. The first disk end face 74a faces the outer end face 73d but is spaced apart from it. In other words, in the stopper unit 70, the second buffer member 74 is spaced apart from the first buffer member 73 in the axial direction of the shaft portion 712.

[0073] The thickness direction of the cover member 75 coincides with the axial direction of the second buffer member 74. The cover member 75 holds the second buffer member 74 by means of a holding portion 75f. The unit base 72e passes through the cover through-hole 75d. The opening direction of the cover through-hole 75d coincides with the axial direction of the stopper 71. In other words, the cover member 75 defines the cover through-hole 75d that passes through in the axial direction of the shaft portion 712. The unit base 72e protrudes from the cover through-hole 75d toward the cover outer surface 75a. The unit forming member 72 has a second connecting end 72g that protrudes from the cover member 75. The second buffer member 74 is sandwiched between the cover member 75 and the flange portion 72d.

[0074] The cover member 75 is located between the flange portion 72d and the marker member 76 in the axial direction of the unit forming member 72. The cover hole defining surface 75c is spaced apart from the unit base outer peripheral surface 722a and surrounds the unit base 72e. In other words, the unit forming member 72 is swingable relative to the cover member 75.

[0075] <Installing the stopper unit to the peripheral wall> As shown in FIGS. 3 and 6 , the two stopper units 70 of the first rotary joint 31 are provided on the peripheral wall 42. The two stopper units 70 are provided on the peripheral wall 42 such that the axes of the stoppers 71 of the two stopper units 70 are parallel to each other in a plane perpendicular to the first rotation axis L1. In other words, one of the two stopper units 70 is located on the axis of the stopper 71 of the other stopper unit 70. The following describes one of the two stopper units 70 provided in the first rotary joint 31. The following description also applies to a stopper unit 70 other than the stopper unit 70 in question.

[0076] As shown in Figures 6 and 7, the stopper unit 70 is provided on the peripheral wall 42. In other words, the stopper 71 is provided on the peripheral wall 42. The stopper unit 70 is inserted through the peripheral wall hole 42a. The stopper engagement portion 711 protrudes from the peripheral wall hole 42a toward the radially inward direction of the peripheral wall 42. Furthermore, the marker member 76 protrudes from the peripheral wall hole 42a toward the radially outward direction of the peripheral wall 42. In other words, the stopper unit 70 is housed in the peripheral wall hole 42a with the stopper engagement portion 711 and the marker member 76 each protruding from the peripheral wall hole 42a.

[0077] The axial direction of the stopper unit 70 and the axial direction of the peripheral wall hole 42a coincide with each other. That is, the shaft portion 712 extends in a direction from the rotating member 50 toward the fixed member 40. The stopper unit 70 is provided on the peripheral wall 42 so that the stopper engagement portion 711 does not come into contact with the rotational outer peripheral surface 51. In other words, the stopper unit 70 has the stopper engagement portion 711 protruding into the peripheral wall hole 42a so as to be separated from the rotational outer peripheral surface 51 in the axial direction of the stopper 71. The stopper unit 70 is also provided on the peripheral wall 42 so that the stopper engagement portion 711 and the rotational engagement portion 55 are aligned in the rotational direction of the rotating member 50. In other words, the stopper unit 70 is provided so that the stopper engagement portion 711 and the rotational engagement portion 55 can come into contact with each other in the rotational direction of the rotating member 50 as the rotating member 50 rotates. In other words, the stopper 71 has the stopper engagement portion 711 that engages with the rotational engagement portion 55 in the circumferential direction of the rotating member 50.

[0078] The stopper unit 70 is housed in the peripheral wall hole 42a so that the buffer outer peripheral surface 73a and the hole-defining surface 42c face each other. That is, the first buffer member 73 has a buffer outer peripheral surface 73a that faces the peripheral wall 42. The first buffer member 73 is housed in the peripheral wall hole 42a. The first buffer member 73 is interposed between the shaft portion 712, the flange portion 72d, and the peripheral wall 42. In the peripheral wall hole 42a, the inclined surface 733a faces the defining inclined surface 423c. The inclined surface 733a and the defining inclined surface 423c are each inclined at the same angle with respect to the axial direction of the stopper 71. That is, by facing the inclined surface 733a, the defining inclined surface 423c restricts radial inward movement of the peripheral wall 42 of the first buffer member 73. In other words, the peripheral wall 42 has a hole-defining surface 42c that engages with the buffer outer peripheral surface 73a and defines the peripheral wall hole 42a. Therefore, the stopper unit 70 restricts the radially inward movement of the peripheral wall 42 in the peripheral wall hole 42a by the defining inclined surface 423c and the inclined surface 733a.

[0079] The lid member 75 is provided at a position where the retaining portion 75f faces the wall outer peripheral surface 421. The lid member 75 is provided on the peripheral wall 42 so that the long axis of the elongated lid through-hole 75d is parallel to the circumferential direction of the peripheral wall 42. In other words, the lid through-hole 75d is elongated, with its long axis extending in the circumferential direction of the peripheral wall 42. The lid member 75 is fixed to the peripheral wall 42 by a pair of lid fixing bolts 92. That is, the lid member 75 is provided in the stopper unit 70 closer to the wall outer peripheral surface 421 than the first buffer member 73 in the axial direction of the shaft portion 712, and is fixed to the peripheral wall 42.

[0080] The cover member 75 restricts the stopper 71, the unit forming member 72, the first buffer member 73, and the second buffer member 74 from moving radially outward in the peripheral wall 42 through the peripheral wall hole 42a. In other words, the first buffer member 73 is held on the peripheral wall 42 by the cover member 75. The cover member 75 is provided on the peripheral wall 42 so that the unit forming member 72 can swing in the circumferential direction of the peripheral wall 42. In other words, the cover member 75 holds the first buffer member 73 so that the marker member 76 can swing in the circumferential direction of the rotating member 50.

[0081] <Installation of the 1st to 3rd rotary joints> 1, the first rotary joint 31 is provided on the base 10 and is interposed between the base 10 and the first support 13. In the first rotary joint 31, the fixed member 40 is fixed to the base 10, and the rotary connection member 56 is fixed to the first support 13 via a rotation restricting member 60. The rotary connection member 56 is fixed to the first support 13 so that the first rotation axis L1 and the first vertical axis Z1 coincide with each other. In other words, the first rotary joint 31 connects the first support 13 and the base 10 so that the first support 13 is rotatable about the first rotation axis L1.

[0082] The second rotary joint 32 is interposed between the second support portion 14 and the second arm 12. In the second rotary joint 32, the fixed member 40 is fixed to the second support portion 14, and the rotary connection member 56 is fixed to the first end of the second arm 12 via a rotation restricting member 60. The rotary connection member 56 is fixed to the first end of the second arm 12 so that the second rotation axis L2 and the second vertical axis Z2 coincide with each other. In other words, the second rotary joint 32 connects the second arm 12 and the second support portion 14 so that the second arm 12 is rotatable about the second rotation axis L2.

[0083] The third rotary joint 33 is provided on the second end side of the second arm 12 and is interposed between the second arm 12 and the load holding portion 15. In the third rotary joint 33, the fixed member 40 is fixed to the second end side of the second arm 12, and the rotary connection member 56 is fixed to the load holding portion 15 via a rotation restricting member 60. The rotary connection member 56 is fixed to the load holding portion 15 so that the third rotation axis L3 and the third vertical axis Z3 coincide with each other. In other words, the third rotary joint 33 connects the load holding portion 15 and the second end of the second arm 12 so that the load holding portion 15 is rotatable about the third rotation axis L3.

[0084] A plurality of cables (not shown) pass through each of the first to third rotary joints 31 to 33. For example, each cable that passes through the inside of the base 10 passes through the bottom wall hole 41a, the first rotary connection hole 50a, and the second rotary connection hole 60a of the first rotary joint 31, and then enters the inside of the first support part 13.

[0085] <Operation of the arm-type assistive device> The arm-type assist device 100 assists a worker in moving an object (not shown). The worker connects the object to the object holding unit 15. The control device 22 detects the load that the object applies to the object holding unit 15. Based on the detection results, the air supply source 21 supplies the actuator 17 with the pressure required for the parallelogram link H to generate a force that balances the load. This supply allows the worker to move the object horizontally and vertically in the Z direction.

[0086] When the worker moves the load, each of first arm 11 and second arm 12 rotates in a horizontal plane. Furthermore, when the worker moves the load, load holding portion 15 rotates relative to second arm 12.

[0087] For example, FIG. 8 shows the movement of the first rotary joint 31 in accordance with the rotation of the first arm 11. In FIG. 8, the first arm 11 and the rotary engagement portion 55 before rotation are each indicated by a two-dot chain line. Also in FIG. 8, the first arm 11 after movement is indicated by a dot-dash line, and the first rotary joint 31 after movement is indicated by a solid line. As the first arm 11 rotates, the rotary member 50 rotates relative to the fixed member 40. The rotary member 50 can rotate until the rotary engagement portion 55 engages with the stopper engagement portion 711. The stopper unit 70 defines a range in which the rotary member 50 can rotate relative to the fixed member 40. Therefore, the first rotary joint 31 defines the rotation range of the rotary member 50 in the rotation chamber 40a by the engagement between the stopper engagement portion 711 and the rotary engagement portion 55.

[0088] [Operation of this embodiment] The operation of this embodiment will be described. In the first to third rotary joints 31 to 33, the stopper unit 70 is fixed to the peripheral wall 42 by a cover member 75. The stopper unit 70 restricts the rotation of the rotary member 50 by engagement between the stopper engagement portion 711 and the rotation engagement portion 55. The impact generated in the stopper 71 and the unit forming member 72 via the stopper engagement portion 711 at the time of this engagement is absorbed by the first buffer member 73.

[0089] The stopper unit 70 can be removed from the peripheral wall hole 42a by removing the cover member 75 from the peripheral wall 42. [Effects of this embodiment] The effects of this embodiment will be described.

[0090] (1) The first buffering member 73 surrounds the shaft portion 712 and the flange portion 72d of the unit forming member 72 and is housed in the peripheral wall hole 42a with the stopper engagement portion 711 protruding. In other words, the first buffering member 73 is provided in a location different from the rotation chamber 40a. Therefore, even if the first buffering member 73 is worn or plastically deformed due to the absorption of an impact by the stopper engagement portion 711, the first buffering member 73 will not fall off between the rotating member 50 and the fixed member 40 and can remain housed in the peripheral wall hole 42a. As a result, each of the first to third rotary joints 31 to 33 can hold the worn or plastically deformed first buffering member 73 in the peripheral wall 42.

[0091] Furthermore, stopper unit 70 can be removed from peripheral wall hole 42a by removing cover member 75 from peripheral wall 42. That is, first buffer member 73 that has been worn or plastically deformed can be removed from peripheral wall hole 42a by removing cover member 75 from peripheral wall 42. Therefore, in first to third rotary joints 31 to 33, stopper unit 70 can be removed from fixed member 40 without interfering with the members connected to fixed member 40 and rotating member 50. As described above, each of first to third rotary joints 31 to 33 can improve the ease of maintenance of stopper unit 70.

[0092] (2) The marker member 76 is provided on the second connecting end 72g that protrudes from the lid through-hole 75d and is swingable relative to the lid member 75. As shown in FIGS. 9 to 12, the stopper engagement portion 711 moves in the circumferential direction of the rotating member 50 when engaging with the rotation engagement portion 55. The marker member 76 moves in conjunction with this movement. The amount of movement of the marker member 76 corresponds to the amount of movement of the stopper engagement portion 711. For example, FIGS. 9 and 10 show the first rotary joint 31 before wear occurs in the first buffering member 73, and FIGS. 11 and 12 show the first rotary joint 31 after wear occurs in the first buffering member 73. When wear occurs in the buffer inner peripheral surface 73b of the first buffering member 73 that faces the rotating member 50, the stopper engagement portion 711 can move more than when no wear occurs in that area. Furthermore, as wear of first buffer member 73 increases, stopper engagement portion 711 moves more due to the impact when engaging with rotation engagement portion 55. In other words, the greater the wear of first buffer member 73, the more marker member 76 moves due to the impact when stopper engagement portion 711 engages with rotation engagement portion 55. As a result, in each of first to third rotary joints 31 to 33, the amount of wear of first buffer member 73 can be determined by checking the amount of movement of marker member 76 without removing first buffer member 73 from peripheral wall 42.

[0093] (3) In the stopper unit 70, the unit forming member 72 can transmit the impact generated when the stopper engaging portion 711 and the rotational engaging portion 55 engage with each other to the second cushioning member 74 in addition to the first cushioning member 73. In other words, when the stopper unit 70 engages with the rotational engaging portion 55, the impact can be absorbed by each of the first cushioning member 73 and the second cushioning member 74. Therefore, the first to third rotary joints 31 to 33 can absorb the impact more efficiently in the stopper unit 70 compared to when the second cushioning member 74 is not provided.

[0094] (4) The inclined surface 733a of the buffer outer peripheral surface 73a engages with the defining inclined surface 423c of the hole defining surface 42c, restricting movement of the first buffer member 73 in the peripheral wall hole 42a in the direction from the wall outer peripheral surface 421 to the wall inner peripheral surface 422. In other words, each of the first to third rotary joints 31 to 33 can more reliably hold the stopper unit 70 in the peripheral wall hole 42a compared to when the inclined surface 733a and the defining inclined surface 423c are not provided.

[0095] Furthermore, in the first buffer member 73, the first buffer outer surface 731a and the second buffer outer surface 732a are connected by an inclined surface 733a. Compared to when the first buffer outer surface 731a and the second buffer outer surface 732a are connected by a surface perpendicular to both surfaces, the contact area with the hole-defining surface 42c can be made larger. As a result, in each of the first to third rotary joints 31 to 33, the contact area between the first buffer member 73 and the hole-defining surface 42c can be made larger compared to when the buffer outer peripheral surface 73a of the first buffer member 73 does not have the inclined surface 733a.

[0096] (5) The first buffer member 73 is held between the stopper 71 and the unit forming member 72 and the peripheral wall 42. The first buffer member 73 absorbs impact by elastically deforming in the axial direction of the peripheral wall hole 42a. The stopper unit 70 provides the second buffer member 74 at a position spaced apart from the first buffer member 73 in the axial direction of the stopper 71, thereby enabling the first buffer member 73 to be held so that it can more easily elastically deform in the axial direction of the peripheral wall hole 42a. As a result, each of the first to third rotary joints 31 to 33 can more efficiently absorb impacts occurring in the stopper 71 compared to when the first buffer member 73 and the second buffer member 74 are not spaced apart in the axial direction of the stopper 71.

[0097] (6) The material of the rotational engagement portion 55 is harder than the material of the stopper engagement portion 711. Therefore, when the stopper engagement portion 711 and the rotational engagement portion 55 engage with each other, wear occurs more in the stopper engagement portion 711 than in the rotational engagement portion 55. The stopper engagement portion 711 can be replaced by removing the stopper unit 70 from the peripheral wall 42, and is therefore easier to replace than the rotational engagement portion 55. Therefore, the stopper unit 70 preferentially causes wear to occur in the stopper engagement portion 711, which is easier to replace than the rotational engagement portion 55, thereby contributing to improved maintainability of the first to third rotary joints 31 to 33.

[0098] [Example of change] The above-described embodiments can be modified as follows: The above-described embodiments and the following modifications can be combined with each other within the scope of technical compatibility.

[0099] The rotation engaging portion 55 does not have to be made of a material harder than the stopper engaging portion 711 . The second buffer member 74 does not have to be spaced apart from the first buffer member 73 in the axial direction of the shaft portion 712. In this case, it is preferable that the second disk end surface 74b of the second buffer member 74 be exposed to the outside of the peripheral wall hole 42a through the lid through-hole 75d.

[0100] The buffer outer surface 73a does not have to have the inclined surface 733a. That is, the buffer outer surface 73a may be composed of a first buffer outer surface 731a and a second buffer outer surface 732a. For example, the first buffer outer surface 731a and the second buffer outer surface 732a may be connected by a surface that is perpendicular to the axial direction of the first buffer member 73.

[0101] The hole-defining surface 42c does not have to engage with the buffer outer peripheral surface 73a. For example, the hole-defining surface 42c may have an inclined surface 733a and a defining inclined surface 423c that are inclined at different angles relative to the axial direction of the stopper 71. The key is that the hole-defining surface 42c only needs to be able to restrict movement of the first buffer member 73 from the peripheral wall hole 42a to the rotation chamber 40a.

[0102] The stopper unit 70 does not necessarily have to include the second buffer member 74. In this case, the first buffer member 73 is preferably long enough in the axial direction so that the outer end surface 73d and the lid inner surface 75b come into contact with each other.

[0103] The lid through-hole 75d does not have to be elongated. For example, the lid through-hole 75d may be elliptical or circular. The stopper unit 70 does not have to include the marker member 76. In this case, the lid member 75 does not have to have the lid through-hole 75d formed therein.

[0104] Each of the first to third rotary joints 31 to 33 may include only one stopper unit 70. In this case, the stopper unit 70 prevents the rotational engagement portion 55 from rotating relative to the fixed member 40 by one revolution.

[0105] The arm-type assist device 100 may include only one of the first to third rotary joints 31 to 33. The rotary joint may not be mounted on the arm-type assist device 100. For example, the rotary joint may be mounted on a transport device having an arm that rotates. Alternatively, the rotary joint may be mounted on a joint portion of a walking assistance device that assists the movement of the knee joint of the wearer. [Explanation of symbols]

[0106] 31-33...first to third rotary joints as rotary joints, 40...fixed member, 40a...rotating chamber, 41...bottom wall, 42...circumferential wall, 42a...circumferential wall hole, 42c...hole defining surface, 50...rotating member, 51...rotating outer peripheral surface as outer peripheral surface, 55...rotational engagement portion, 70...stopper unit, 71...stopper, 72...unit forming member, 72d...flange portion, 72f...first connecting end, 72g...second connecting end, 73...first cushioning member as cushioning member, 73a...cushioning outer peripheral surface, 74...second cushioning member, 75...lid member, 75d...lid through hole, 76...marker member, 421...wall outer peripheral surface, 422...wall inner peripheral surface, 711...stopper engagement portion, 712...shaft portion, 712a...first shaft end, 712b...second shaft end, 733a...inclined surface.

Claims

1. a rotating member having a rotational engagement portion on an outer circumferential surface; a fixed member including a bottom wall supporting the rotary member and a peripheral wall extending from an edge of the bottom wall and surrounding the rotary member and the rotational engagement portion; a stopper provided on the peripheral wall, The stopper is a stopper engagement portion that engages with the rotation engagement portion in the circumferential direction of the rotary member; a shaft portion extending in a direction from the rotating member toward the fixed member, the shaft portion having a first shaft end portion on which the stopper engagement portion is provided, and a second shaft end portion in the axial direction, the fixed member accommodates the rotating member in a rotation chamber defined by the bottom wall and the peripheral wall, and the rotation engagement portion is rotatable along the peripheral wall; a rotary joint that defines a rotation range of the rotary member in the rotary chamber by engagement between the stopper engagement portion and the rotation engagement portion, a stopper unit including the stopper and inserted into peripheral wall holes opening in the outer peripheral surface and the inner peripheral surface of the peripheral wall; The stopper unit is a buffer member through which the shaft portion passes and through which the stopper engagement portion protrudes, the buffer member being accommodated in the peripheral wall hole; a unit forming member having a flange portion facing the buffer member in the axial direction and in a direction perpendicular to the axial direction, the unit forming member being provided continuously with the second shaft end portion in the axial direction and being inserted inside the buffer member; a cover member that is provided closer to the wall outer peripheral surface than the buffer member in the axial direction and is fixed to the peripheral wall, A rotary joint, characterized in that the buffer member is interposed between the shaft portion and the flange portion and the peripheral wall, and the buffer member is held to the peripheral wall by the cover member.

2. The cover member defines a cover through-hole that penetrates in the axial direction, the unit forming member has a first connecting end portion connected to the second shaft end portion and having the flange portion, and a second connecting end portion penetrating the lid through-hole and protruding from the lid member, The second connection end is provided with a marking member that interlocks with the stopper, The lid through-hole has an elongated hole shape with a long axis extending in the circumferential direction, 2. The rotary joint according to claim 1, wherein the outer diameter of the second connection end of the unit forming member is smaller than the width of an opening in the direction in which the major axis extends.

3. When the buffer member is a first buffer member, the stopper unit has a second buffer member, the second connection end of the unit forming member penetrates the second buffer member, 3. The rotary joint according to claim 2, wherein the second buffer member is sandwiched between the cover member and the flange portion in the axial direction.

4. the first buffer member has a buffer outer peripheral surface facing the peripheral wall, the buffer outer peripheral surface has an inclined surface in which the outer diameter of the first buffer member increases along a direction from the first shaft end toward the second shaft end, 4. The rotary joint of claim 3, wherein the peripheral wall has a hole-defining surface that engages the buffer outer peripheral surface and defines the peripheral wall hole.

5. 4. The rotary joint according to claim 3, wherein the second buffer member is spaced apart from the first buffer member in the axial direction.

6. 3. The rotary joint according to claim 1, wherein the rotational engagement portion is made of a material harder than that of the stopper engagement portion.

Images