Spherical link mechanism and spherical link actuator

Abstract

To provide a spherical link mechanism which can obtain a bend angle having 90° or larger while having high stiffness, and a spherical link operation device.SOLUTION: A spherical link mechanism 101 comprises a base-end side link hub 31, a tip-side link hub 32, a base-end side link member 33, a tip-side link member 34, a center link member 35, a beam member 50, a first connecting part 51, and a second connecting part 52. The beam member 50 is bridged so as to pass a first spherical link center point and a second spherical link center point between the base-end side link hub 31 and the tip-side link hub 32. The first connecting part 51 connects one end of the beam member 50 to the base-end side link hub 31 so as to be inclined to the base-end side link hub 31. The second connecting part 52 connects the other end of the beam member 50 to the tip-side link hub 32 so as to be inclined to the tip-side link hub 32. The first connecting part 51 and the second connecting part 52 are joints having rotation 2-degree of freedoms.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a spherical link mechanism and a spherical link actuator. [Background technology]

[0002] Patent Document 1 (JP 2005-351379 A) describes a link actuator. The link actuator described in Patent Document 1 has two spherical link mechanisms and a spherical structure that connects the two spherical link mechanisms.

[0003] Specifically, the link actuation device described in Patent Document 1 includes a spherical link mechanism including an input member, an end link member, and a central link member, a spherical link mechanism including an output member, an end link member, and a central link member, and a spherical structure connecting the input member and the output member. The spherical structure includes a pair of spherical members that are in spherical contact with each other. The spherical structure is configured as a joint (ball joint) with three degrees of freedom of rotation.

[0004] The link actuation device described in Patent Document 1 is equipped with a spherical structure in addition to multiple link mechanisms, and therefore has higher rigidity than a link actuation device that has multiple link mechanisms but does not have a spherical structure. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2005-351379 A Summary of the Invention [Problem to be solved by the invention]

[0006] In the link actuation device described in Patent Document 1, it was difficult to make the angle (bend angle) between the central axis of the input member and the central axis of the output member 90 degrees. This is because the spherical structure is composed of an input-side spherical member, an output-side spherical member, and a connecting portion between them, and in order to increase the bend angle, the spherical contact area of ​​the other cup-shaped spherical member is limited to avoid interference with one of the spherical members including the connecting portion, making it easier for one spherical member to detach from the other spherical member, and making it difficult to maintain a state in which the two spherical members are rotatably connected (spherical contact state).

[0007] A primary object of the present invention is to provide a spherical link mechanism and a spherical link actuator which have high rigidity and yet can achieve a 90 degree bending angle. [Means for solving the problem]

[0008] The spherical link mechanism according to the present invention includes a base link hub, a tip link hub, a base link member, a tip link member, and a central link member. One end of the base link member is connected to the base link hub so as to be rotatable about a first rotation axis. One end of the tip link member is connected to the tip link hub so as to be rotatable about a second rotation axis. The other end of the base link member is connected to one end of the central link member so as to be rotatable about a third rotation axis. The other end of the tip link member is connected to the other end of the central link member so as to be rotatable about a fourth rotation axis. The first central axis, the first rotation axis, and the third rotation axis of the base link hub intersect at a center point of the first spherical link. The second central axis, the second rotation axis, and the fourth rotation axis of the tip link hub intersect at a center point of the second spherical link. The spherical link mechanism further includes a beam member extending between the base end link hub and the tip end link hub so as to pass through the first spherical link center point and the second spherical link center point, a first connecting portion connecting one end of the beam member to the base end link hub so as to be tiltable relative to the base end link hub, and a second connecting portion connecting the other end of the beam member to the tip end link hub so as to be tiltable relative to the tip end link hub.

[0009] Each of the first connecting portion and the second connecting portion of the spherical link mechanism is a joint with two rotational degrees of freedom.

[0010] In the above spherical link mechanism, at least one of the first connecting portion and the second connecting portion may be a universal joint.

[0011] In the above spherical link mechanism, the first connecting portion may be connected to the base end link hub rotatably relative to the base end link hub about a fifth rotation axis perpendicular to the first center axis of the base end link hub, and may be connected to the beam member rotatably relative to the beam member about a sixth rotation axis perpendicular to both the first center axis and the fifth rotation axis. The second connecting portion may be connected to the tip end link hub rotatably relative to the tip end link hub about a seventh rotation axis perpendicular to the second center axis of the tip end link hub, and may be connected to the beam member rotatably relative to the beam member about an eighth rotation axis perpendicular to both the second center axis and the seventh rotation axis.

[0012] In the above spherical link mechanism, at least one of the first connecting portion and the second connecting portion may be a Cardan joint.

[0013] In the above spherical link mechanism, the first connecting portion may be connected to the base end link hub so as to be rotatable about a first central axis, and the second connecting portion may be connected to the tip end link hub so as to be rotatable about a second central axis.

[0014] In the above spherical link mechanism, the first connecting portion may be connected to the base end link hub so as not to rotate about a first center axis of the base end link hub, and connected to the beam member so as to be rotatable relative to the beam member about a ninth rotation axis that passes through a center point of the first spherical link, is perpendicular to the first center axis, and is rotatable about the first center axis. The second connecting portion may be connected to the tip end link hub so as not to rotate about a second center axis of the tip end link hub, and connected to the beam member so as to be rotatable relative to the beam member about a tenth rotation axis that passes through a center point of the second spherical link, is perpendicular to the second center axis, and is rotatable about the second center axis.

[0015] In the above spherical link mechanism, at least one of the first connecting portion and the second connecting portion may be a constant velocity joint.

[0016] In the above spherical link mechanism, the first connecting portion may be connected to one end of the beam member rotatably about an eleventh rotation axis that passes through a center point of the first spherical link and is perpendicular to the first center axis, and may be connected to the base-side link hub rotatably about a first center axis of the base-side link hub. The second connecting portion may be connected to the other end of the beam member rotatably about a twelfth rotation axis that passes through a center point of the second spherical link and is perpendicular to the second center axis, and may be connected to the tip-side link hub rotatably about a second center axis of the tip-side link hub.

[0017] The spherical link actuation device according to the present invention includes the spherical link mechanism and at least two drive sources. The position and orientation of the tip side link hub relative to the base side link hub are determined by the at least two drive sources.

[0018] In the spherical link actuation device, each of the at least two drive sources may rotate the base end link member about the first rotation axis.

[0019] The spherical link actuation device may include the spherical link mechanism, a driving source that rotates the first connecting portion and the beam member around a first central axis, and a driving source that rotates the beam member around an eleventh rotation axis.

[0020] In the above-mentioned spherical link actuation device, one end of the beam member and the base end link hub may be connected via a rotational resistance reduction member, and the other end of the beam member and the tip end link hub may be connected via a rotational resistance reduction member.

[0021] In the above-mentioned spherical link actuation device, the beam member may include a damping portion that damps vibration in the extension direction of the beam member.

[0022] In the spherical link actuation device, each of the beam member, the first connecting portion, and the second connecting portion may be hollow. Effect of the Invention

[0023] According to the present invention, it is possible to provide a spherical link mechanism and a spherical link actuator that have high rigidity and yet realizes a 90-degree bending angle. [Brief description of the drawings]

[0024] [Figure 1] FIG. 2 is a perspective view showing a spherical link mechanism according to the first embodiment. [Diagram 2] FIG. 2 is a cross-sectional view taken along line II-II in FIG. [Diagram 3] FIG. 3 is a cross-sectional view taken along line III-III in FIG. [Figure 4] 4A to 4C are diagrams illustrating a beam member, a first connecting portion, and a second connecting portion of the spherical link mechanism according to the first embodiment. [Diagram 5] 3 is a cross-sectional view of the spherical link mechanism according to the first embodiment when it is in a second position different from the first position shown in FIG. 2. [Figure 6] 6A to 6C are diagrams illustrating modified examples of the beam member, the first connecting portion, and the second connecting portion of the spherical link mechanism according to the first embodiment. [Figure 7] FIG. 1 is a perspective view showing a link actuator according to a first embodiment. [Figure 8] FIG. 11 is a perspective view showing a spherical link mechanism and a spherical link actuator according to a second embodiment. [Figure 9] 9 is a cross-sectional view taken along line IX-IX in FIG. 8. [Figure 10] 10 is a partially enlarged cross-sectional view illustrating a beam member, a second connecting portion, and a tip side link hub of the spherical link mechanism shown in FIG. 9. [Figure 11] 9 is a perspective view of the spherical link mechanism and the spherical link actuation device according to the second embodiment when the spherical link mechanism and the spherical link actuation device are in a second position different from the first position shown in FIG. [Figure 12]12 is a cross-sectional view taken along line XII-XII in FIG. 11. [Figure 13] FIG. 11 is a perspective view showing a spherical link actuator and a spherical link actuator according to a third embodiment. [Figure 14] 14 is a plan view showing the spherical link actuator and the spherical link actuator shown in FIG. 13. FIG. [Figure 15] 14 is a cross-sectional view taken along line XV-XV in FIG. 13. [Figure 16] 13 is a perspective view for explaining a base end link hub, a tip end link hub, a beam member, a first connecting portion, and a second connecting portion of a spherical link mechanism according to embodiment 3. FIG. [Figure 17] 17 is a front view of the base end link hub, the tip end link hub, the beam member, the first connecting portion, and the second connecting portion shown in FIG. 16. FIG. [Figure 18] 18 is a cross-sectional view taken along line XVIII-XVIII in FIG. 16. [Figure 19] 17 is a cross-sectional view of the base end link hub, the tip end link hub, the beam member, the first connecting portion, and the second connecting portion shown in FIG. 16 when they are in a second position different from the first positions shown in FIGS. 16 to 18. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following drawings, the same or corresponding parts are designated by the same reference characters, and overlapping descriptions will not be repeated.

[0026] (Embodiment 1) <Configuration of spherical link mechanism 101> As shown in FIG. 1 and FIG. 2, the spherical link mechanism 101 includes a base end link hub 31, a tip end link hub 32, a plurality of link mechanisms, a beam member 50, a first connecting portion 51, and a second connecting portion 52. The plurality of link mechanisms include a plurality of base end link members 33, a plurality of tip end link members 34, a plurality of central link members 35, a plurality of first rotating shafts 41, a plurality of second rotating shafts 42, a plurality of third rotating shafts 43, and a plurality of fourth rotating shafts 44. Each link mechanism includes one base end link member 33, one tip end link member 34, one central link member 35, one first rotating shaft 41, one second rotating shaft 42, one third rotating shaft 43, and one fourth rotating shaft 44. Although not shown, for example, an end effector is attached to the tip end link hub 32.

[0027] As shown in FIG. 2, the base end link hub 31 has, for example, an opening 31A. The opening 31A penetrates, for example, between a surface of the base end link hub 31 facing the tip end link hub 32 and a surface facing the opposite side. The opening 31A includes a first hole 31B that opens on the surface facing the tip end link hub 32, and a second hole 31C that is connected to the first hole 31B and opens on the surface facing the opposite side to the tip end link hub 32. The central axis of the first hole 31B is connected to the central axis of the second hole 31C in the same straight line. The central axis of the opening 31A extends in a straight line. The central axis of the opening 31A coincides with the first central axis C1 of the base end link hub 31. The opening width of the second hole 31C is wider than the opening width of the first hole 31B.

[0028] As shown in Figs. 2 and 3, the tip side link hub 32 has, for example, an opening 32A. The opening 32A penetrates, for example, the tip side link hub 32 between a surface facing the base side link hub 31 side and a surface facing the opposite side. The opening 32A includes a first hole portion 32B that opens on the surface facing the base side link hub 31 side, and a second hole portion 32C that is connected to the first hole portion 32B and opens on the surface facing the opposite side to the base side link hub 31 side. The central axis of the opening 32A extends linearly. The central axis of the opening 32A coincides with the second central axis C2 (see Fig. 2) of the tip side link hub 32.

[0029] 2, the opening 31A of the base end link hub 31 accommodates a part of a first connecting portion 51, which will be described later. The opening 32A of the tip end link hub 32 accommodates a part of a second connecting portion 52, which will be described later.

[0030] Each of the base-side link members 33 has the same configuration. One end of the base-side link member 33 is connected to the base-side link hub 31 so as to be rotatable around a first rotating shaft 41. The first rotating shaft 41 is configured, for example, integrally with the base-side link hub 31. The first rotating shaft 41 protrudes outward from the base-side link hub 31, for example, along a radial direction relative to the first central axis C1 of the base-side link hub 31. For example, a through hole is formed in the one end of the base-side link member 33. The first rotating shaft 41 is passed through the through hole. The base-side link member 33 has, for example, an L-shape.

[0031] The tip side link members 34 have the same configuration. One end of the tip side link member 34 is connected to the tip side link hub 32 so as to be rotatable around a second rotating shaft 42. The second rotating shaft 42 is configured, for example, integrally with the tip side link hub 32. The second rotating shaft 42 protrudes outward from the tip side link hub 32, for example, along a radial direction relative to the second central axis C2 of the tip side link hub 32. For example, a through hole is formed in the one end of the tip side link member 34. The second rotating shaft 42 is passed through the through hole. The tip side link member 34 has, for example, an L-shape.

[0032] Each central link member 35 has the same configuration. One end of the central link member 35 is connected to the other end of the base end link member 33 so as to be rotatable about a third rotation shaft 43. The other end of the central link member 35 is connected to the other end of the tip end link member 34 so as to be rotatable about a fourth rotation shaft 44. The central link member 35 has, for example, an L-shape.

[0033] The number of the link mechanisms is, for example, 3. In this case, the first rotating shafts 41 are arranged, for example, with rotational symmetry of 120 degrees with respect to the first central axis line. The number of the link mechanisms may be 4 or more.

[0034] As shown in FIG. 2, the first central axis C1 of the base end link hub 31, the central axis R1 of the first rotating shaft 41, and the central axis R3 of the third rotating shaft 43 intersect at one point. This point is called the first spherical link center point P1. The second central axis C2 of the tip end link hub 32, the central axis R2 of the second rotating shaft 42, and the central axis R4 of the fourth rotating shaft 44 intersect at one point. This point is called the second spherical link center point P2. That is, the spherical link mechanism 101 has a structure in which two spherical link mechanisms are combined. As a result, the tip end link hub 32 moves on a spherical surface (hereinafter sometimes referred to as a "first moving spherical surface") centered on the first spherical link center point P1 by rotating the base end link member 33 around the first rotating shaft 41.

[0035] As shown in FIG. 2, the beam member 50 is stretched between the base end link hub 31 and the tip end link hub 32. The beam member 50 passes through the first spherical link center point P1 and the second spherical link center point P2. The beam member 50 has a central axis C3 that passes through the first spherical link center point P1 and the second spherical link center point P2. One end of the beam member 50 is connected to the base end link hub 31 via the first connecting portion 51 so as to be rotatable with two degrees of freedom relative to the base end link hub 31. The other end of the beam member 50 is connected to the tip end link hub 32 via the second connecting portion 52 so as to be rotatable with two degrees of freedom relative to the tip end link hub 32. The beam member 50 includes, for example, a second yoke member 55 and a fourth yoke member 58, which will be described later. One end of the beam member 50 is constituted by the second yoke member 55. The other end of the beam member 50 is constituted by the fourth yoke member 58.

[0036] The first connecting portion 51 connects one end of the beam member 50 to the base end link hub 31. The first connecting portion 51 is a joint with two degrees of freedom of rotation, such as a universal joint, and a more specific example is a Cardan joint. The two degrees of freedom of rotation of the first connecting portion 51 are a degree of freedom of rotation about a fifth rotation axis perpendicular to the first central axis C1 of the base end link hub 31, and a degree of freedom of rotation about a sixth rotation axis perpendicular to each of the first central axis C1 and the fifth rotation axis of the base end link hub 31. This allows the beam member 50 to move with the above two degrees of freedom relative to the base end link hub 31.

[0037] The first connecting portion 51 includes a first shaft member 53, a first yoke member 54, and a second yoke member 55 forming a part of the beam member 50. The first shaft member 53 has a fifth rotation shaft 53A extending in a direction perpendicular to the first central axis C1 of the base end link hub 31, and a sixth rotation shaft 53B extending in a direction perpendicular to each of the first central axis and the fifth rotation shaft 53A. The first yoke member 54 has, for example, a yoke portion 54A disposed closer to the tip end link hub 32 than the base end link hub 31, and an insertion portion 54B passing through the second hole portion 31C of the opening 31A of the base end link hub 31. The yoke portion 54A is connected to the fifth rotation shaft 53A rotatably around the fifth rotation shaft 53A. As a result, the first yoke member 54 is connected to the first shaft member 53 rotatably around the fifth rotation shaft 53A. The second yoke member 55 has, for example, a yoke portion 55A disposed closer to the base end link hub 31 than the tip end link hub 32, and a shaft portion 55B protruding on the opposite side to the yoke portion 55A. The yoke portion 55A is connected to the sixth rotation shaft 53B so as to be rotatable about the sixth rotation shaft 53B. As a result, the second yoke member 55 is connected to the first shaft member 53 so as to be rotatable about the sixth rotation shaft 53B.

[0038] The first yoke member 54 is housed in the opening 31A of the base-side link hub 31. The first yoke member 54 is positioned relative to the base-side link hub 31 in a direction along the first central axis C1 and in a radial direction relative to the first central axis. The first yoke member 54 is connected to the base-side link hub 31 to be rotatable about the first central axis. As a result, in this embodiment, the beam member 50 can move with three degrees of freedom relative to the base-side link hub 31.

[0039] The first yoke member 54 may be connected to the base end link hub 31 so as not to be rotatable about the first central axis C1.

[0040] The second connecting portion 52 connects the other end of the beam member 50 to the tip side link hub 32. The second connecting portion 52 is a joint with two degrees of freedom of rotation, such as a universal joint, and a more specific example is a Cardan joint. The two degrees of freedom of rotation of the second connecting portion 52 are a degree of freedom of rotation about a seventh rotation axis perpendicular to the second central axis C2 of the tip side link hub 32, and a degree of freedom of rotation about an eighth rotation axis perpendicular to each of the second central axis C2 and the seventh rotation axis of the tip side link hub 32. This allows the beam member 50 to operate with the above two degrees of freedom relative to the tip side link hub 32.

[0041] The second connecting portion 52 includes a second shaft member 56, a third yoke member 57, and a fourth yoke member 58 forming another part of the beam member 50. The second shaft member 56 has a seventh rotation shaft 56A extending in a direction perpendicular to the second central axis C2 of the tip side link hub 32, and an eighth rotation shaft 56B extending in a direction perpendicular to each of the second central axis C2 and the seventh rotation shaft 56A. The third yoke member 57 has, for example, a yoke portion 57A disposed closer to the base end side link hub 31 than the tip side link hub 32, and an insertion portion 57B passing through the second hole portion 32C of the opening 32A of the tip side link hub 32. The yoke portion 57A is connected to the seventh rotation shaft 56A rotatably around the seventh rotation shaft 56A. As a result, the third yoke member 57 is connected to the second shaft member 56 rotatably around the seventh rotation shaft 56A. The fourth yoke member 58 has, for example, a yoke portion 58A disposed closer to the tip side link hub 32 than the base side link hub 31, and a shaft portion 58B protruding on the opposite side to the yoke portion 58A. The yoke portion 58A is connected to the eighth rotation shaft 56B so as to be rotatable about the eighth rotation shaft 56B. Thus, the fourth yoke member 58 is connected to the second shaft member 56 so as to be rotatable about the eighth rotation shaft 56B.

[0042] The third yoke member 57 is housed in the opening 32A of the tip side link hub 32. The third yoke member 57 is positioned relative to the tip side link hub 32 in a direction along the second central axis and in a radial direction relative to the second central axis. The third yoke member 57 is connected to the tip side link hub 32 to be rotatable about the second central axis. This allows the beam member 50 to move with three degrees of freedom relative to the tip side link hub 32 in this embodiment.

[0043] The third yoke member 57 may be connected to the tip side link hub 32 so as not to be rotatable about the second central axis C2.

[0044] As an example, the eighth rotation shaft 56B is parallel to the fifth rotation shaft 53A and extends in the same direction, and in this case, the seventh rotation shaft 56A is parallel to the sixth rotation shaft 53B and extends in the same direction.

[0045] In the beam member 50, the shaft portion 55B and the shaft portion 58B are, for example, hollow. Each of the shaft portion 55B and the shaft portion 58B is, for example, a tubular member.

[0046] <Configuration of the spherical link actuator 201> As shown in FIG. 7, the spherical link actuation device 201 according to the first embodiment includes a spherical link mechanism 101 and a plurality of driving sources 61 and 62. Each of the plurality of driving sources 61 and 62 is, for example, a motor. The plurality of driving sources 61 and 62 include a plurality of driving sources 61 and a driving source 62. Each of the plurality of driving sources 61 is attached to the base end link hub 31 and rotates each base end link member 33 around the first rotation shaft 41. This allows the position and attitude of the tip end link hub 32 relative to the base end link hub 31 to be changed. The driving source 62 rotates the first connecting portion 51 around the first central axis. This allows the rotation to be transmitted in the order of the first connecting portion 51 to the beam member 50 and the second connecting portion 52, and the end effector installed on the tip end link hub 32 can be rotated around the second central axis.

[0047] <Effects of the spherical link mechanism 101 and the spherical link actuator 201> The spherical link mechanism 101 includes, in addition to multiple link mechanisms, a beam member 50 passing through the first spherical link center point P1 and the second spherical link center point P2. Therefore, in the spherical link mechanism 101, the first spherical link center point P1 and the second spherical link center point P2 are connected by one rigid body, and the distance between the first spherical link center point P1 and the second spherical link center point P2 is maintained regardless of the bending angle. Therefore, the spherical link mechanism 101 has higher rigidity and is less likely to deform than a spherical link mechanism that includes multiple link mechanisms but does not include a beam member. As a result, the operation accuracy of the spherical link mechanism 101 is higher than that of a spherical link mechanism that includes multiple link mechanisms but does not include a beam member.

[0048] 5, the bend angle of the spherical link mechanism 101 can be 90 degrees or more. The bend angle of the spherical link mechanism 101 is the angle between the first central axis C1 of the base end link hub 31 and the second central axis C2 of the tip end link hub 32. This is because the first angle between the first central axis C1 of the base end link hub 31 and the central axis of the beam member 50, and the second angle between the second central axis C2 of the tip end link hub 32 and the central axis of the beam member 50 can be 45 degrees or more. In this way, the spherical link mechanism 101 can achieve a bend angle of 90 degrees or more while having high rigidity.

[0049] In the spherical link mechanism 101, each of the first connecting portion 51 and the second connecting portion 52 is a Cardan joint.

[0050] Therefore, even if the first angle formed by the first central axis C1 of the base-side link hub 31 and the central axis of the beam member 50 becomes 45 degrees or more, the state in which one end of the beam member 50 and the base-side link hub 31 are rotatably connected can be maintained. Similarly, even if the second angle formed by the second central axis C2 of the tip-side link hub 32 and the central axis of the beam member 50 becomes 45 degrees or more, the state in which the other end of the beam member 50 and the tip-side link hub 32 are rotatably connected can be maintained. As a result, in the spherical link mechanism 101, a state in which the first angle and the second angle are simultaneously 45 degrees can be realized. At this time, the bending angle becomes 90 degrees.

[0051] Furthermore, each of first connecting portion 51 and second connecting portion 52 can be manufactured more easily than a ball joint. A ball joint has a pair of spherical surfaces that make spherical contact, but high machining precision is required to allow such a pair of spherical surfaces to slide. In contrast, a universal joint does not have such spherical surfaces, so it can be manufactured more easily than a ball joint.

[0052] In addition, a ball joint has a structure in which a pair of spherical surfaces are provided so as to be in spherical contact with each other, and therefore a cup-shaped joint member holds a spherical joint member of approximately the same dimensions. In order to realize such a structure, when assembling a ball joint, it is necessary to accommodate the spherical joint member in a cup-shaped joint member having an opening narrower than the diameter by, for example, deforming the cup-shaped joint member or dividing the cup-shaped joint member into a cup member and a cover member. Deforming or dividing the cup-shaped joint member reduces the accuracy of the spherical surface formed in the cup-shaped joint member. Therefore, while a ball joint requires high machining accuracy for a pair of spherical surfaces, it is difficult to improve the accuracy of the spherical surfaces by ingenuity during assembly to realize the structure (for example, deformation or division of the cup-shaped joint member). In contrast, a universal joint has a shaft and a hole provided so as to be in surface contact with each other, and therefore does not require machining accuracy like a ball joint, and does not require ingenuity to realize the structure, making it easy to process and assemble.

[0053] In the spherical link mechanism 101, the first connecting part 51 is connected to the base end link hub 31 so as to be rotatable about a first central axis, and the second connecting part 52 is connected to the tip end link hub 32 so as to be rotatable about a second central axis. Therefore, when the first connecting part 51 is rotated about the first central axis by the driving source 62, the second connecting part 52 can also rotate about the second central axis.

[0054] If each of the shaft portions 55B and 58B of the beam member 50 is hollow, the components of the spherical link actuator 201 can be accommodated inside the beam member 50. If each of the shaft portions 55B and 58B of the beam member 50 is a tubular member, cables, piping, etc. can be passed through each of the shaft portions 55B and 58B.

[0055] <Modification> Each of the first connecting portion 51 and the second connecting portion 52 may further include a plurality of rotational resistance reduction members 59 (see FIG. 6). The plurality of rotational resistance reduction members 59 can reduce friction between each rotating shaft and each yoke portion. The plurality of rotational resistance reduction members 59 are, for example, rolling bearings.

[0056] As shown in FIG. 6, the second connecting portion 52 includes two rotational resistance reduction members 59, the inner ring of which is fitted onto the seventh rotating shaft 56A and the outer ring of which is fitted onto the third yoke member 57, and two rotational resistance reduction members 59, the inner ring of which is fitted onto the eighth rotating shaft 56B and the outer ring of which is fitted onto the fourth yoke member 58.

[0057] Although FIG. 6 shows the second connecting portion 52 including a plurality of rotational resistance reducing members 59, the first connecting portion 51 may also have a similar configuration to the second connecting portion 52.

[0058] The first connecting portion 51 may be connected to the base end link hub 31 so as not to rotate about the first central axis C1. Similarly, the second connecting portion 52 may be connected to the tip end link hub 32 so as not to rotate about the second central axis C2. A spherical link actuator including such a spherical link mechanism does not include a drive source 62.

[0059] The spherical link mechanism 101 may further include a rotational resistance reduction member that reduces friction between each rotation shaft and each link member. Such a rotational resistance reduction member is, for example, a rolling bearing.

[0060] (Embodiment 2) 8 to 10, spherical link mechanism 102 according to embodiment 2 has a configuration basically similar to that of spherical link mechanism 101 and achieves similar effects, but differs from spherical link mechanism 101 in that it includes beam member 70, first connecting portion 71, and second connecting portion 72 instead of beam member 50, first connecting portion 51, and second connecting portion 52. The following mainly describes the differences from spherical link mechanism 101.

[0061] The beam member 70 has a central axis C3 that passes through the first spherical link center point P1 and the second spherical link center point P2. The beam member 70 includes, for example, an inner joint member 73 and an inner joint member 76, which will be described later. One end of the beam member 70 is formed by the inner joint member 73. The other end of the beam member 70 is formed by the inner joint member 76.

[0062] The beam member 70 further includes, for example, a damping portion 70A for damping vibration in the extension direction of the beam member 70, a shaft portion 70B connecting one end of the damping portion 70A in the extension direction and the inner joint member 73, and a shaft portion 70C connecting the other end of the damping portion 70A in the extension direction and the inner joint member 76. The damping portion 70A is, for example, a damper.

[0063] Each of the first connecting portion 71 and the second connecting portion 72 is a constant velocity joint. A constant velocity joint connects two shafts, a driving side and a driven side, and has a structure capable of transmitting rotational torque at a constant speed even when the two shafts form an operating angle. In other words, the first connecting portion 71 is connected to the base end link hub 31 so as not to rotate around the first central axis C1 of the base end link hub 31 with respect to the base end link hub 31. Furthermore, the first connecting portion 71 is connected to the beam member 70 so as to be rotatable around a ninth rotation axis R9 (see FIG. 9 ) that passes through the first spherical link center point P1 and is perpendicular to the first central axis C1 with respect to the beam member 70. Furthermore, the ninth rotation axis R9 can rotate around the first central axis C1. Therefore, the first connecting portion 71 has two degrees of freedom of rotation, and the base end link hub 31 and the beam member 70 have a constant speed of rotation.

[0064] Specifically, the first connecting portion 71 includes an inner joint member 73 that forms a part of the beam member 70, a cup-shaped outer joint member 74 that houses the inner joint member 73, and a plurality of rolling elements 75. The outer joint member 74 is formed integrally with the base-end link hub 31. The plurality of rolling elements 75 are disposed between the inner joint member 73 and the outer joint member 74.

[0065] On the outer circumferential surface of the inner joint member 73, a plurality of track grooves 73A are formed on a spherical surface centered on the first spherical link center point P1 at equal intervals in the circumferential direction of the central axis C3 of the beam member 70. On the inner circumferential surface of the outer joint member 74, a plurality of track grooves 74A are formed on a spherical surface centered on the first spherical link center point P1 at equal intervals in the circumferential direction of the first central axis C1. Each of the plurality of track grooves 73A extends along the central axis C3 of the beam member 70. Each of the plurality of track grooves 74A extends along the first central axis C1. The shape of a cross section perpendicular to the above-mentioned extension direction of each of the plurality of track grooves 73A and the plurality of track grooves 74A is an arc shape. Each of the plurality of track grooves 74A faces each of the plurality of track grooves 73A. Each rolling element 75 is interposed between a pair of track grooves 73A and 74A facing each other to transmit rotational torque.

[0066] In the constant velocity joint configured as described above, when an angle (operating angle) about the ninth rotation axis R9 is applied between the inner joint member 73 and the outer joint member 74, the rolling elements 75 are always maintained on the plane bisecting the operating angle. This ensures constant velocity between the inner joint member 73 and the outer joint member 74. Between the inner joint member 73 and the outer joint member 74, rotational torque is transmitted via the rolling elements 75 with constant velocity being ensured.

[0067] The second connecting portion 72 has a configuration similar to that of the first connecting portion 71. The second connecting portion 72 connects the beam member 70 to the tip side link hub 32 so as not to rotate around the second central axis C2 of the tip side link hub 32. Furthermore, the second connecting portion 72 connects the beam member 70 to the tip side link hub 32 so as to be rotatable relative to the tip side link hub 32 around a tenth rotation axis R10 (see FIG. 9) that passes through the second spherical link center point P2 and is perpendicular to the second central axis C2. Furthermore, the tenth rotation axis R10 can rotate around the second central axis C2. Therefore, the second connecting portion 72 has two degrees of freedom of rotation, and the tip side link hub 32 and the beam member 70 have uniform speed of rotation.

[0068] Specifically, the second connecting portion 72 includes an inner joint member 76 that forms a part of the beam member 70, a cup-shaped outer joint member 77 that houses the inner joint member 76, and a plurality of rolling elements 78. The outer joint member 77 is formed integrally with the tip side link hub 32. The plurality of rolling elements 78 are disposed between the inner joint member 76 and the outer joint member 77.

[0069] On the outer circumferential surface of the inner joint member 76, a plurality of track grooves 76A are formed on a spherical surface centered on the second spherical link center point P2 at equal intervals in the circumferential direction of the central axis C3 of the beam member 70. On the inner circumferential surface of the outer joint member 77, a plurality of track grooves 77A are formed on a spherical surface centered on the second spherical link center point P2 at equal intervals in the circumferential direction of the second central axis C2. Each of the plurality of track grooves 76A extends along the central axis C3 of the beam member 70. Each of the plurality of track grooves 77A extends along the second central axis C2. The shape of a cross section perpendicular to the above-mentioned extension direction of each of the plurality of track grooves 76A and the plurality of track grooves 77A is an arc shape. Each of the plurality of track grooves 77A faces each of the plurality of track grooves 76A. Each rolling element 78 is interposed between a pair of opposing track grooves 76A and 77A to transmit rotational torque.

[0070] In the constant velocity joint configured as described above, when an angle (operating angle) about the tenth rotation axis R10 is applied between the inner joint member 76 and the outer joint member 77, the rolling elements 78 are always maintained on the plane bisecting the operating angle. This ensures constant velocity between the inner joint member 76 and the outer joint member 77. Rotational torque is transmitted between the inner joint member 76 and the outer joint member 77 via the rolling elements 78 while constant velocity is ensured. Therefore, the inner joint member 76 and the outer joint member 77 rotate at a constant speed.

[0071] More specifically, rotational torque is transmitted at a constant speed through the base end link hub 31, the beam member 70, and the tip end link hub 32 in that order.

[0072] The number of the plurality of rolling bodies 75 and the number of each of the plurality of rolling bodies 78 is, for example, 6. Note that the number of the plurality of rolling bodies 75 and the number of each of the plurality of rolling bodies 78 may be any number other than 6. The plurality of rolling bodies 75, 78 are, for example, steel balls or ceramic balls.

[0073] <Configuration of the spherical link actuator 202> The spherical link actuation device 202 according to the second embodiment includes a spherical link mechanism 102 and a plurality of drive sources 61. Each of the plurality of drive sources 61 may have a configuration equivalent to that of the plurality of drive sources 61 of the spherical link actuation device 201. Each of the plurality of drive sources 61 is attached to the base end link hub 31, and rotates each base end link member 33 around the first rotation shaft 41.

[0074] <Effects of the spherical link mechanism 102 and the spherical link actuator 202> The spherical link mechanism 102 and the spherical link actuator 202 basically have the same configuration as the spherical link mechanism 101 and the spherical link actuator 201, and therefore can achieve the same effects as these.

[0075] 11 and 12, the bending angle of the spherical link mechanism 102 can be 90 degrees or more. This is because the first angle θ1 (see FIG. 12) between the first central axis C1 of the base side link hub 31 and the central axis C3 of the beam member 70, and the second angle θ2 (see FIG. 12) between the second central axis C2 of the tip side link hub 32 and the central axis C3 of the beam member 70 can be 45 degrees or more.

[0076] In the spherical link mechanism 102, each of the first connecting portion 71 and the second connecting portion 72 is a constant velocity joint. Therefore, even if the first angle θ1 formed by the first central axis C1 of the base end link hub 31 and the central axis C3 of the beam member 70 becomes 45 degrees or more, the state in which one end of the beam member 70 and the base end link hub 31 are rotatably connected can be maintained. Similarly, even if the second angle θ2 formed by the second central axis C2 of the tip end link hub 32 and the central axis C3 of the beam member 70 becomes 45 degrees or more, the state in which the other end of the beam member 70 and the tip end link hub 32 are rotatably connected can be maintained. As a result, even in the spherical link mechanism 102, a state in which the first angle θ1 and the second angle θ2 are simultaneously 45 degrees can be realized. At this time, the bending angle is 90 degrees.

[0077] Furthermore, constant velocity joints are used in the first connecting portion 71 and the second connecting portion 72, so that constant velocity can be obtained with no speed change during one rotation.

[0078] In addition, the spherical link mechanism 102 and the spherical link actuator 202 have both a rotational uniformity due to the base end link hub 31 and the tip end link hub 32 being connected between them by the first connecting portion 71, the beam member 70, and the second connecting portion 72, and a rotational uniformity due to the base end link hub 31 and the tip end link hub 32 being connected by multiple links formed by the base end link member, the central link member, and the tip end link member. The two rotational uniformities are consistent and transmit rotational torque in the same direction, so posture changes are smoother than those of the spherical link mechanism 101 and the spherical link actuator 201 which have universal joints.

[0079] Furthermore, each of the first connecting portion 71 and the second connecting portion 72 can be manufactured more easily than a ball joint.

[0080] Furthermore, the first connecting portion 71 and the second connecting portion 72 have excellent durability because the load is always borne by the multiple rolling elements 75. For example, even when the entire spherical link mechanism 102 rotates, the multiple rolling elements 75 receive the load, so the spherical link mechanism 102 is resistant to torsion and has high reliability.

[0081] Furthermore, since the beam member 70 includes the damping portion 70A, even if the tip-side link hub 32 vibrates in the axial direction of the beam member 70 during operation of the spherical link mechanism 102, the damping portion 70A can dampen the vibration and suppress the vibration from being transmitted to the base-side link hub 31. Note that, like the beam member 70, the beam member 50 of the spherical link mechanism 101 may also include a damping portion for damping vibration in the extension direction of the beam member 50.

[0082] (Embodiment 3) 13 to 19, spherical link mechanism 103 according to embodiment 3 basically has the same configuration as spherical link mechanism 101 and achieves the same effects, but differs from spherical link mechanism 101 in that it has beam member 80, first connecting portion 81, and second connecting portion 82 instead of beam member 50, first connecting portion 51, and second connecting portion 52. The following mainly describes the differences from spherical link mechanism 101.

[0083] The beam member 80 has a central axis C3 that passes through the first spherical link center point P1 and the second spherical link center point P2.

[0084] The first connecting portion 81 is connected to the base-end link hub 31 so as to be rotatable around a first central axis C1 of the base-end link hub 31. Furthermore, the first connecting portion 81 is connected to one end of the beam member 80 so as to be rotatable around an eleventh rotation axis 84 perpendicular to the first central axis C1. The two rotational degrees of freedom of the first connecting portion 81 are a rotational degree of freedom around the first central axis C1 of the base-end link hub 31 and a rotational degree of freedom around the eleventh rotation axis 84 perpendicular to the first central axis C1 of the base-end link hub 31. This allows the beam member 80 to move with the above two degrees of freedom relative to the base-end link hub 31.

[0085] Specifically, the first connecting portion 81 includes the base end link hub 31, a first member 83, and an eleventh rotating shaft 84. The first member 83 has, for example, a yoke portion 83A disposed closer to the tip end link hub 32 than the base end link hub 31, and an insertion portion 83B passing through a second hole portion 31C of the opening 31A of the base end link hub 31. The first member 83 is connected to the base end link hub 31 so as to be rotatable around a first central axis C1 of the base end link hub 31. A tooth profile 83C is formed on the yoke portion 83A of the first member 83. The tooth profile 83C is formed so as to extend along the circumferential direction with respect to the central axis of the eleventh rotating shaft 84. The tooth profile 83C is provided so as to mesh with a gear 66, which will be described later.

[0086] A through hole 80A is formed in one end of the beam member 80. A through hole 83D is formed in the yoke portion 83A of the first member 83. An eleventh rotation shaft 84 passes through each of the through hole 80A and the through hole 83D. The yoke portion 83A of the first member 83 is connected to one end of the beam member 80 so as to be rotatable around the eleventh rotation shaft 84 relative to the beam member 80.

[0087] The second connecting portion 82 is connected to the tip side link hub 32 rotatably about the second central axis C2 of the tip side link hub 32. Furthermore, the second connecting portion 82 is connected to the other end of the beam member 80 rotatably about a twelfth rotation axis 86 perpendicular to the second central axis C2. The two rotational degrees of freedom of the second connecting portion 82 are a rotational degree of freedom about the second central axis C2 of the tip side link hub 32 and a rotational degree of freedom about the twelfth rotation axis 86 perpendicular to the second central axis C2 of the tip side link hub 32. This allows the beam member 80 to move with the above two degrees of freedom relative to the tip side link hub 32.

[0088] Specifically, the second connecting portion 82 includes a second member 85 and a twelfth rotating shaft 86. The second member 85 has, for example, a yoke portion 85A disposed closer to the base end link hub 31 than the tip end link hub 32, and an insertion portion 85B passed through the second hole portion 32C of the opening 32A of the tip end link hub 32. The second member 85 is connected to the tip end link hub 32 rotatably about the second center axis C2 of the tip end link hub 32.

[0089] A through hole 80B is formed in the other end of the beam member 80. A through hole 85D is formed in the yoke portion 85A of the second member 85. A twelfth rotation shaft 86 passes through each of the through holes 80B and 85D. The yoke portion 85A of the second member 85 is connected to the other end of the beam member 80 so as to be rotatable relative to the beam member 80 around the twelfth rotation shaft 86.

[0090] In other words, the base end link hub 31, the beam member 80, and the first connecting portion 81 constitute a pan-tilt mechanism. The tip end link hub 32, the beam member 80, and the second connecting portion 82 constitute a pan-tilt mechanism. Note that, like the beam member 70, the beam member 80 of the spherical link mechanism 103 may also include a damping portion for damping vibration in the extension direction of the beam member 80.

[0091] <Configuration of the spherical link actuator 203> A spherical link actuation device 203 according to the third embodiment includes a spherical link mechanism 103, and a driving source 63 and a driving source 64. The driving source 63 is fixed to the base end link hub 31 by a driving source fixing member 87. The driving source 63 rotates the first member 83 relative to the base end link hub 31 about the first central axis.

[0092] The driving source 64 is fixed to the beam member 80. The driving source 64 includes a shaft portion 65 that extends along an eleventh rotation axis 84 and is rotatable around the extension direction as a central axis, and a gear 66 fixed to the shaft portion 65. The driving source 64 rotates the shaft portion 65 and the gear 66 around the central axis of the shaft portion 65. The gear 66 is provided so as to mesh with a tooth profile 83C of the first member 83. As a result, when the driving source 64 rotates the shaft portion 65, the shaft portion 65, the gear 66, and the driving source 64 rotate around the eleventh rotation axis 84 relative to the first member 83. As a result, the beam member 80 fixed to the driving source 64 is inclined with respect to the first central axis C1. The attitude of the beam member 80, that is, the first angle θ1 (see FIG. 19) between the central axis C3 (see FIGS. 18 and 19) of the beam member 80 and the first central axis C1 is determined by the drive source 64.

[0093] <Effects of the spherical link mechanism 103 and the spherical link actuator 203> The spherical link mechanism 103 and the spherical link actuator 203 basically have the same configuration as the spherical link mechanism 101 and the spherical link actuator 201, and therefore can achieve the same effects as these.

[0094] 19, the bending angle of the spherical link mechanism 103 can be 90 degrees or more. This is because the first angle formed by the first central axis C1 of the base side link hub 31 and the central axis C3 of the beam member 80, and the second angle θ2 formed by the second central axis C2 of the tip side link hub 32 and the central axis C3 of the beam member 80 can be 45 degrees or more.

[0095] In the spherical link mechanism 103, each of the first connecting portion 81 and the second connecting portion 82 constitutes a part of the pan-tilt mechanism. Therefore, even if the first angle θ1 formed by the first central axis C1 of the base end link hub 31 and the central axis C3 of the beam member 80 becomes 45 degrees or more, the state in which one end of the beam member 80 and the base end link hub 31 are rotatably connected can be maintained. Similarly, even if the second angle θ2 formed by the second central axis C2 of the tip end link hub 32 and the central axis C3 of the beam member 80 becomes 45 degrees or more, the state in which the other end of the beam member 80 and the tip end link hub 32 are rotatably connected can be maintained. As a result, even in the spherical link mechanism 103, a state in which the first angle θ1 and the second angle θ2 are simultaneously 45 degrees can be realized. At this time, the bending angle becomes 90 degrees.

[0096] Furthermore, each of the first connecting portion 81 and the second connecting portion 82 can be manufactured more easily than a ball joint.

[0097] In spherical link mechanism 103, proximal link hub 31 and distal link hub 32 may each have different dimensions.

[0098] Although the embodiment of the present invention has been described above, the above-mentioned embodiment can be modified in various ways. The scope of the present invention is not limited to the above-mentioned embodiment. The scope of the present invention is defined by the claims, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0099] 31 base end link hub, 31A, 32A opening, 31B, 32B first hole portion, 31C, 32C second hole portion, 32 tip end link hub, 33 base end link member, 34 tip end link member, 35 central link member, 41 first rotating shaft, 42 second rotating shaft, 43 third rotating shaft, 44 fourth rotating shaft, 50, 70, 80 beam member, 51, 71, 81 first connecting portion, 52, 72, 82 second connecting portion, 53 first shaft member, 53A fifth rotating shaft, 53B sixth rotating shaft, 54 first yoke member, 54A, 55A, 57A, 58A, 83A, 85A yoke portion, 54B, 57B, 83B, 85B insertion portion, 55 second yoke member, 55B, 58B shaft portion, 56 Second shaft member, 56A seventh rotating shaft, 56B eighth rotating shaft, 57 third yoke member, 58 fourth yoke member, 59 rotational resistance reduction member, 61, 62, 63, 64 driving source, 65, 70B, 70C shaft portion, 66 gear, 70A damping portion, 73, 76 inner joint member, 73A, 74A, 76A, 77A track groove, 74, 77 outer joint member, 75, 78 rolling element, 80A, 80B, 83D, 85D through hole, 83 first member, 83C tooth profile, 84 eleventh rotating shaft, 85 second member, 86 twelfth rotating shaft, 87 driving source fixing member, 101, 102, 103 spherical link mechanism, 201, 202, 203 spherical link actuator.

Claims

1. A base end link hub; A tip side link hub; A base end link member; A tip side link member; A central link member. One end of the base end link member is connected to the base end link hub so as to be rotatable around a first rotation axis, One end of the tip side link member is connected to the tip side link hub so as to be rotatable around a second rotation axis, the other end of the base end link member is connected to one end of the central link member so as to be rotatable around a third rotation axis; the other end of the tip side link member is connected to the other end of the central link member so as to be rotatable around a fourth rotation axis, a first central axis of the base end link hub, the first rotation axis, and the third rotation axis intersect at a first spherical link center point, a second center axis of the tip side link hub, the second rotation axis, and the fourth rotation axis intersect at a second spherical link center point, a beam member extending between the base end link hub and the tip end link hub so as to pass through the first spherical link center point and the second spherical link center point; a first connecting portion connecting one end of the beam member to the base end link hub so as to be inclined relative to the base end link hub; a second connecting portion connecting the other end of the beam member to the tip side link hub so as to be inclined relative to the tip side link hub, A spherical link mechanism, wherein each of the first connecting portion and the second connecting portion is a joint with two rotational degrees of freedom.

2. 2. The spherical link mechanism according to claim 1, wherein at least one of the first connecting portion and the second connecting portion is a universal joint.

3. the first connecting portion is connected to the base-end link hub rotatably relative to the base-end link hub about a fifth rotation axis perpendicular to the first central axis of the base-end link hub, and is connected to the beam member rotatably relative to the beam member about a sixth rotation axis perpendicular to both the first central axis and the fifth rotation axis, 3. The spherical link mechanism according to claim 2, wherein the second connecting portion is connected to the tip side link hub so as to be rotatable relative to the tip side link hub about a seventh rotation axis perpendicular to the second center axis of the tip side link hub, and is connected to the beam member so as to be rotatable relative to the beam member about an eighth rotation axis perpendicular to both the second center axis and the seventh rotation axis.

4. 4. The spherical linkage according to claim 3, wherein at least one of the first connecting portion and the second connecting portion is a Cardan joint.

5. the first connecting portion is connected to the base end link hub so as to be rotatable about the first central axis, 5. The spherical link mechanism according to claim 3, wherein the second connecting portion is connected to the tip side link hub so as to be rotatable about the second central axis.

6. the first connecting portion is connected to the base end link hub so as not to rotate relative to the base end link hub around the first central axis of the base end link hub, and is connected to the beam member so as to be rotatable relative to the beam member around a ninth rotation axis that passes through the first spherical link center point, is perpendicular to the first central axis, and rotates around the first central axis, 3. The spherical link mechanism according to claim 2, wherein the second connecting portion is connected to the tip side link hub so as not to rotate relative to the tip side link hub about the second center axis of the tip side link hub, and is connected to the beam member so as to be rotatable relative to the beam member about a tenth rotation axis that passes through the second spherical link center point, is perpendicular to the second center axis, and rotates about the second center axis.

7. 7. The spherical link mechanism according to claim 6, wherein at least one of the first connecting portion and the second connecting portion is a constant velocity joint.

8. the first connecting portion is connected to one end of the beam member rotatably relative to the beam member about an eleventh rotation axis perpendicular to the first central axis, and is connected to the base-side link hub rotatably relative to the base-side link hub about the first central axis of the base-side link hub, 2. The spherical link mechanism according to claim 1, wherein the second connecting portion is connected to the other end of the beam member so as to be rotatable relative to the beam member about a twelfth rotation axis perpendicular to the second center axis, and is connected to the tip side link hub so as to be rotatable relative to the tip side link hub about the second center axis of the tip side link hub.

9. The spherical link mechanism according to any one of claims 1 to 7; At least two drive sources; A spherical link actuator, wherein the position and orientation of the tip side link hub relative to the base side link hub are determined by the at least two drive sources.

10. 10. The spherical link actuation device according to claim 9, wherein each of the at least two drive sources rotates the base end link member about the first rotation axis.

11. The spherical link mechanism according to claim 8 ; a drive source that rotates the first connecting portion and the beam member about the first central axis; a drive source that rotates the beam member about the eleventh rotation axis.

12. One end of the beam member and the base end link hub are connected via a rotational resistance reducing member, The spherical link actuator according to any one of claims 9 to 11, wherein the other end of the beam member and the tip side link hub are connected via a rotational resistance reducing member.

13. The spherical link actuation device according to any one of claims 9 to 12, wherein the beam member includes a damping portion for damping vibration in the extension direction of the beam member.

14. The spherical link actuation device according to any one of claims 9 to 13, wherein each of the beam member, the first connecting portion, and the second connecting portion is hollow.

Images