JP7612481B2 - Spherical link mechanism and spherical link actuator - Google Patents

Description

The present invention relates to a spherical link mechanism and a spherical link actuator.

JP 2014-119069 A (Patent Document 1) describes a spherical link mechanism. The spherical link mechanism described in Patent Document 1 has a base end link hub, a tip end link hub, and multiple links.

Each of the multiple links has a first end link member, a second end link member, and an intermediate link member. The first end link member is rotatably connected to the base end link hub at one end of the first end link member around a first rotation axis. The second end link member is rotatably connected to the tip end link hub at one end of the second end link member around a second rotation axis. The intermediate link member is rotatably connected to the other end of the first end link member around a third rotation axis at one end of the intermediate link hub, and is rotatably connected to the other end of the second end link member around a fourth rotation axis at the other end of the intermediate link hub.

The central axis of the base link hub, the first rotation axis, and the third rotation axis intersect at the center point of the first rotation link. The base link hub moves on a spherical surface centered on the center point of the first rotation link. The central axis of the tip link hub, the second rotation axis, and the fourth rotation axis intersect at the center point of the second rotation link. The tip link hub moves on a spherical surface centered on the center point of the second rotation link. In other words, the spherical link mechanism described in Patent Document 1 is structured by combining two spherical links.

JP 2014-119069 A

In order to prevent dust, water droplets, oil droplets, wear powder, etc. from adhering to the spherical link mechanism described in Patent Document 1, it is considered effective to attach a cover to the spherical link mechanism described in Patent Document 1. The cover is attached, for example, to the base end link hub at one end and to the tip end link hub at the other end, so that multiple links are stored in the internal space.

The spherical link mechanism described in Patent Document 1 can achieve a bending angle of 90°. However, if an attempt is made to achieve the above range of motion using a cover made of rubber, resin, or other material, the cover may be damaged.

The present invention has been made in consideration of the problems with the conventional technology described above. More specifically, the present invention provides a spherical link mechanism and a spherical link actuator that can prevent damage to the cover when achieving a large bending angle.

The spherical link mechanism of the present invention includes a base link hub, a tip link hub, a plurality of links, and a cover. Each of the plurality of links includes a first end link member, a second end link member, and an intermediate link member. The first end link member is connected to the base link hub at one end of the first end link member so as to be rotatable around a first rotation axis. The second end link member is connected to the tip link hub at one end of the second end link member so as to be rotatable around a second rotation axis. The intermediate link member is connected to the other end of the first end link member so as to be rotatable around a third rotation axis at one end of the intermediate link member, and is connected to the other end of the second end link member so as to be rotatable around a fourth rotation axis at the other end of the intermediate link member. The first central axis, which is the central axis of the base link hub, the first rotation axis, and the third rotation axis intersect at the center point of the first spherical link. The second central axis, which is the central axis of the tip link hub, the second rotation axis, and the fourth rotation axis intersect at the center point of the second spherical link. The base link hub moves on a first moving spherical surface centered on the center point of the first spherical link. The tip link hub moves on a second moving spherical surface centered on the center point of the second spherical link. The cover has a cover relay member, a base end cover, and a tip end cover. The cover relay member is disposed outside the multiple links so as to intersect with the intermediate plane where the first moving spherical surface and the second moving spherical surface intersect. One end and the other end of the base end cover are attached to the base end link hub and the cover relay member, respectively. One end and the other end of the tip end cover are attached to the tip link hub and the cover relay member, respectively. Multiple links are disposed in the internal space of the cover.

In the above-mentioned spherical link mechanism, the cover relay member may be integrated with one of the intermediate link members among the multiple links.

In the above-mentioned spherical link mechanism, the cover relay member may be connected to at least one intermediate link member of the multiple links so as to be rotatable around a fifth rotation axis passing through the center point of the first spherical link and the center point of the second spherical link.

In the above-mentioned spherical link mechanism, the multiple links may include a first link and multiple second links. The cover relay member may be integrated with an intermediate link member of the first link. The cover relay member may be connected to at least one intermediate link member of the multiple second links so as to be rotatable around a fifth rotation axis passing through the center point of the first spherical link and the center point of the second spherical link.

The spherical link actuation device of the present invention comprises the spherical link mechanism described above and at least two drive sources. Each of the at least two drive sources rotates the first end link member of each of the multiple links about a first rotation axis.

The spherical link mechanism and spherical link actuator of the present invention can prevent damage to the cover when achieving a large bending angle.

1 is a perspective view of the spherical link mechanism 100 with the cover 40 omitted. FIG. FIG. 2 is a front view of the spherical link mechanism 100. 3 is a cross-sectional view taken along line III-III in FIG. 2. FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. FIG. 2 is a front view of the spherical link mechanism 100A. 6 is a cross-sectional view taken along line VI-VI in FIG. 5. FIG. 2 is a front view of the spherical link mechanism 100B. 8 is a cross-sectional view taken along line VIII-VIII in FIG. 7. FIG. 9 is an enlarged view of region IX in FIG. 8 . FIG. 2 is a front view of the spherical link actuator 200. 11 is a cross-sectional view taken along line XI-XI of FIG.

Details of the embodiments of the present invention will be described below with reference to the drawings. In the following drawings, the same or corresponding parts are given the same reference symbols, and redundant explanations will not be repeated.

First Embodiment
A spherical link mechanism according to a first embodiment (hereinafter, referred to as a "spherical link mechanism 100") will be described.

<Configuration of spherical link mechanism 100>
Fig. 1 is a perspective view of a spherical link mechanism 100 without a cover 40. As shown in Fig. 1, the spherical link mechanism 100 has a base end link hub 10, a tip end link hub 20, and a plurality of links 30. Although not shown, for example, an end effector is attached to the tip end link hub 20.

Each of the multiple links 30 is connected to a base end link hub 10 and a tip link hub 20. Each of the multiple links 30 has a first end link member 31, a second end link member 32, and an intermediate link member 33. The number of the multiple links 30 is, for example, three. However, the number of the multiple links 30 is not limited to this. The number of the multiple links 30 may be four or more. The multiple links 30 are, for example, arranged at equal intervals from each other. Note that the shape of the base end link hub 10 and the shape of the tip link hub 20 are, for example, the same.

The first end link member 31 is connected to the base end link hub 10 at one end of the first end link member 31 so as to be rotatable around a first rotation axis. The second end link member 32 is connected to the tip end link hub 20 so as to be rotatable around a second rotation axis. The intermediate link member 33 is connected to the other end of the first end link member 31 at one end of the intermediate link member 33 so as to be rotatable around a third rotation axis. The intermediate link member 33 is connected to the other end of the second end link member 32 so as to be rotatable around a fourth rotation axis.

The central axis of the base link hub 10 is the first central axis, and the central axis of the tip link hub 20 is the second central axis. The first central axis, the first rotation axis, and the third rotation axis intersect at one point. This point is the first spherical link center point. The second central axis, the second rotation axis, and the fourth rotation axis intersect at a point other than the first spherical link center point. This other point is the second spherical link center point.

The base link hub 10 moves on a spherical surface (first moving spherical surface) centered on the center point of the first spherical link. The tip link hub 20 moves on a spherical surface (second moving spherical surface) centered on the center point of the second spherical link. In other words, the spherical link mechanism 100 has a structure in which two spherical links are combined.

The plane where the first moving spherical surface and the second moving spherical surface intersect is the mid-plane IP (see FIG. 3). The two spherical links included in the spherical link mechanism 100 move symmetrically with respect to the mid-plane IP. The angle between the first central axis and the second central axis is the bend angle. The tip link hub 20 moves so as to form a bend angle of 0° or more and 90° or less with respect to the base link hub 10.

Figure 2 is a front view of the spherical link mechanism 100. Figure 3 is a cross-sectional view taken along III-III in Figure 2. Figure 4 is a cross-sectional view taken along IV-IV in Figure 2. As shown in Figures 2, 3, and 4, the spherical link mechanism 100 has a cover 40. The cover 40 has a cover relay member 41, a base end cover 42, and a tip end cover 43. The shapes of the base end cover 42 and the tip end cover 43 are, for example, the same.

The base end cover 42 and the tip end cover 43 are made of a flexible material. The base end cover 42 and the tip end cover 43 are made of, for example, rubber or a resin material. However, the base end cover 42 and the tip end cover 43 may be made of other materials.

The cover relay member 41 is annular (ring-shaped). It is preferable that the cover relay member 41 is annular. The cover relay member 41 is disposed outside the multiple links 30. The cover relay member 41 is disposed so as to intersect with the intermediate plane IP.

The cover relay member 41 is composed of, for example, a first annular member 41a and a second annular member 41b. The second annular member 41b is arranged so that the inner peripheral surface of the second annular member 41b faces the outer peripheral surface of the first annular member 41a. In other words, the second annular member 41b is arranged on the outside of the first annular member 41a.

The base-end cover 42 is cylindrical and hollow inside. One end of the base-end cover 42 is attached to the base-end link hub 10. The other end of the base-end cover 42 is attached to the cover relay member 41. More specifically, the other end of the base-end cover 42 is sandwiched between the outer peripheral surface of the first annular member 41a and the inner peripheral surface of the second annular member 41b.

The tip cover 43 is cylindrical and hollow inside. One end of the tip cover 43 is attached to the tip link hub 20. The other end of the tip cover 43 is attached to the cover relay member 41. More specifically, the other end of the tip cover 43 is sandwiched between the outer peripheral surface of the first annular member 41a and the inner peripheral surface of the second annular member 41b.

A plurality of links 30 are arranged in the internal space of the cover 40. A part or all of the base end link hub 10 is arranged in the internal space of the cover 40, and a part or all of the tip end link hub 20 may also be arranged in the internal space of the cover 40. This prevents dust, water droplets, oil droplets, wear powder, etc. from adhering to the inside of the spherical link mechanism 100.

<Effects of the spherical link mechanism 100>
The spherical link mechanism 100 operates so that the base end link hub 10 and the tip end link hub 20 are symmetrical with respect to the intermediate plane IP. In addition, in the spherical link mechanism 100, the cover relay member 41 is disposed at a position intersecting the intermediate plane IP, so that when the spherical link mechanism 100 operates, the base end cover 42 and the tip end cover 43 are also deformed symmetrically with respect to the intermediate plane IP. Therefore, even when the bending angle is large (for example, when the bending angle is 90°), the deformation of the cover 40 as a whole is evenly distributed to the base end cover 42 and the tip end cover 43. Therefore, according to the spherical link mechanism 100, damage to the base end cover 42 and the tip end cover 43 is suppressed when a large bending angle is realized.

Second Embodiment
A spherical link mechanism according to a second embodiment (hereinafter, referred to as a "spherical link mechanism 100A") will be described. Here, differences from the spherical link mechanism 100 will be mainly described, and overlapping descriptions will not be repeated.

Figure 5 is a front view of the spherical link mechanism 100A. Figure 6 is a cross-sectional view taken along line VI-VI in Figure 5. As shown in Figures 5 and 6, in the spherical link mechanism 100A, the cover relay member 41 is integrated with one of the intermediate link members 33 of the multiple links 30.

In the spherical link mechanism 100, the cover relay member 41 is not attached to any of the multiple links 30, so when an external force is applied to the cover 40, the entire cover 40 may deform and come into contact with the multiple links 30.

On the other hand, in the spherical link mechanism 100A, the cover relay member 41 is integrated with one of the intermediate link members 33 among the multiple links 30. Therefore, even if an external force is applied to the cover 40, the intermediate link member 33 supports the external force, preventing the entire cover 40 from being deformed.

Third Embodiment
A spherical link mechanism according to a third embodiment (hereinafter, referred to as a "spherical link mechanism 100B") will be described. Here, differences from the spherical link mechanism 100 will be mainly described, and overlapping descriptions will not be repeated.

Figure 7 is a front view of the spherical link mechanism 100B. Figure 8 is a cross-sectional view taken along line VIII-VIII in Figure 7. Figure 9 is an enlarged view of region IX in Figure 8. As shown in Figures 7 to 9, in the spherical link mechanism 100B, a groove 41aa is formed in the inner circumferential surface of the first annular member 41a. The inner circumferential surface of the first annular member 41a is recessed toward the outer circumferential surface of the first annular member 41a at the groove 41aa. The groove 41aa extends in the circumferential direction of the first annular member 41a.

Each intermediate link member 33 of the multiple links 30 has a protrusion 33a. The protrusion 33a is inserted into the groove 41aa. This allows the cover relay member 41 to be connected to each intermediate link member 33 of the multiple links 30 so as to be rotatable around the fifth rotation axis.

The fifth rotation axis passes through the center point of the first spherical link and the center point of the second spherical link. In other words, the fifth rotation axis passes through the center of the intermediate plane IP and is perpendicular to the intermediate plane IP. Therefore, even if the cover relay member 41 is connected to each of the intermediate link members 33 of the multiple links 30 so as to be rotatable around the fifth rotation axis, the operation of the spherical link mechanism 100B does not change.

The cover relay member 41 does not have to be connected to all of the intermediate link members 33 of the multiple links 30 so as to be rotatable around the fifth rotation axis. One of the multiple links 30 is defined as a first link. The multiple links 30 other than the first link are defined as multiple second links. In the spherical link mechanism 100B, the intermediate link member 33 of the first link may be integrated with the cover relay member 41, and the cover relay member 41 may be connected to at least one of the multiple second links so as to be rotatable around the fifth rotation axis.

In the spherical link mechanism 100, the intermediate link members 33 of each of the multiple links 30 are not interconnected, so there is room for improvement in the rigidity of the entire spherical link mechanism 100. On the other hand, in the spherical link mechanism 100B, the cover relay member 41 is connected to each of the intermediate link members 33 of each of the multiple links 30, so the load applied to the multiple links 30 is also distributed to the cover relay member 41, improving the rigidity of the entire spherical link mechanism 100B.

Fourth Embodiment
A spherical link actuation device according to a fourth embodiment (hereinafter, referred to as a "spherical link actuation device 200") will be described.

Figure 10 is a front view of the spherical link actuation device 200. Figure 11 is a cross-sectional view taken along line XI-XI in Figure 10. As shown in Figures 10 and 11, the spherical link actuation device 200 has a spherical link mechanism 100B and multiple drive sources 110.

In the spherical link actuation device 200, the spherical link mechanism 100 or the spherical link mechanism 100A may be used instead of the spherical link mechanism 100B. In the spherical link actuation device 200, the shape of the base end link hub 10 and the shape of the tip end link hub 20 are not the same (the base end link hub 10 is larger than the tip end link hub 20), and the shape of the base end cover 42 and the shape of the tip end cover 43 are not the same.

The number of the multiple driving sources 110 is, for example, equal to the number of the multiple links 30. However, the number of the multiple driving sources 110 may be at least two or more. Each of the multiple driving sources 110 rotates the first end link member 31 of each of the multiple links 30 around the first central axis. Each of the multiple driving sources 110 is driven independently. This determines the position and orientation of the tip link hub 20 relative to the base link hub 10.

The base link hub 10 has an inner surface and an outer surface. The inner surface of the base link hub 10 faces the internal space of the cover 40. The outer surface of the base link hub 10 is the surface opposite the inner surface of the base link hub 10. A plurality of through holes 10a are formed in the base link hub 10. Each of the plurality of through holes 10a passes through the base link hub 10 and communicates with the internal space of the cover 40.

Each of the multiple driving sources 110 has a main body 110a and a rotating shaft 110b. The main body 110a is attached to the outer surface of the base end link hub 10. The central axis of the rotating shaft 110b is perpendicular to the direction of the first rotating shaft. The main body 110a rotates the rotating shaft 110b around the central axis of the rotating shaft 110b. The rotating shaft 110b of each of the multiple driving sources 110 is inserted into each of the multiple through holes 10a.

The spherical link actuator 200 further includes a plurality of helical gear mechanisms 120. Each of the plurality of helical gear mechanisms 120 is disposed in the internal space of the cover 40.

Each of the multiple helical gear mechanisms 120 has a first helical gear 121 and a second helical gear 122. The first helical gear 121 is attached to one end of the first end link member 31 of each of the multiple links 30, and the second helical gear 122 is attached to the rotation shaft 110b of each of the multiple driving sources 110. The first helical gear 121 rotates around the first rotation shaft together with the first end link member 31. The second helical gear 122 rotates together with the rotation shaft 110b. The first helical gear 121 meshes with the second helical gear 122.

Therefore, when the rotation shaft 110b of each of the multiple drive sources 110 rotates, the first end link member 31 of each of the multiple links 30 rotates around the first rotation shaft, and the position and attitude of the tip link hub 20 relative to the base link hub 10 is changed.

The spherical link actuator 200 eliminates the need to form a hole in the cover 40 (base end cover 42 and tip end cover 43) for passing the rotating shaft 110b in order to attach multiple drive sources 110. Therefore, the spherical link actuator 200 prevents dust, water droplets, oil droplets, wear powder, etc. from entering the internal space of the cover 40 through the hole formed in the cover 40.

Although the embodiment of the present invention has been described above, the above embodiment can be modified in various ways. Furthermore, the scope of the present invention is not limited to the above embodiment. The scope of the present invention is indicated by the claims, and is intended to include all modifications that are equivalent in meaning and scope to the claims.

The above embodiment is particularly advantageously applicable to spherical link mechanisms and spherical link actuators having spherical link mechanisms.

10 base end link hub, 10a through hole, 20 tip end link hub, 30 link, 31 first end link member, 32 second end link member, 33 intermediate link member, 33a protrusion, 40 cover, 41 cover relay member, 41a first annular member, 41aa groove, 41b second annular member, 42 base end cover, 43 tip end cover, 100, 100A, 100B spherical link mechanism, 110 drive source, 110a main body, 110b rotating shaft, 120 helical gear mechanism, 121 first helical gear, 122 second helical gear, 200 spherical link actuator, IP intermediate plane.

Claims (5)

A proximal link hub;
A tip link hub and a plurality of links;
and a cover.
Each of the plurality of links includes a first end link member, a second end link member, and an intermediate link member,
the first end link member is connected to the base end link hub at one end of the first end link member so as to be rotatable about a first rotation axis;
The second end link member is connected to the tip link hub at one end of the second end link member so as to be rotatable about a second rotation axis,
the intermediate link member is connected at one end thereof to the other end of the first end link member so as to be rotatable about a third rotation axis, and is connected at the other end thereof to the other end of the second end link member so as to be rotatable about a fourth rotation axis,
a first central axis line, which is a central axis line of the base end link hub, the first rotation axis line, and the third rotation axis line intersect at a first spherical link center point,
a second central axis line, which is a central axis line of the tip link hub, the second rotation axis line, and the fourth rotation axis line intersect at a center point of a second spherical link,
the base end link hub moves on a first moving spherical surface centered on the first spherical link center point;
the tip link hub moves on a second moving spherical surface centered on the second spherical link center point;
The cover includes a cover relay member, a base end cover, and a tip end cover,
the cover relay member is disposed outside the plurality of links so as to intersect with an intermediate plane where the first moving spherical surface and the second moving spherical surface intersect,
one end and the other end of the base-end cover are attached to the base-end link hub and the cover relay member, respectively;
one end and the other end of the tip side cover are attached to the tip link hub and the cover relay member, respectively;
A spherical link mechanism, wherein the plurality of links are disposed in the internal space of the cover. The spherical link mechanism according to claim 1, wherein the cover relay member is integrated with the intermediate link member of one of the multiple links. The spherical link mechanism according to claim 1, wherein the cover relay member is connected to the intermediate link member of at least one of the multiple links so as to be rotatable about a fifth rotation axis passing through the center point of the first spherical link and the center point of the second spherical link. The plurality of links includes a first link and a plurality of second links,
2. The spherical link mechanism according to claim 1, wherein the cover relay member is integrated with the intermediate link member of the first link and is connected to the intermediate link member of at least one of the plurality of second links so as to be rotatable around a fifth rotation axis passing through the first spherical link center point and the second spherical link center point. The spherical link mechanism according to any one of claims 1 to 4,
At least two drive sources;
Each of the at least two drive sources rotates the first end link member of each of the plurality of links about the first axis of rotation.

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