JP7189528B2 - Parallel link mechanism and link actuator - Google Patents

Description

The present invention relates to a parallel link mechanism and a link actuation device.

2. Description of the Related Art Parallel link mechanisms used in various devices such as medical equipment and industrial equipment are conventionally known (see, for example, Patent Documents 1 and 2).

JP-A-2000-94245 U.S. Pat. No. 5,893,296

The parallel link mechanism of Patent Document 1 has a relatively simple configuration, but each link has a small operating angle. Therefore, if the operating range of the traveling plate is set to be large, the length of the link is increased, which causes the size of the entire mechanism to increase, resulting in an increase in the size of the device.

The parallel link mechanism of Patent Document 2 has a configuration in which a base-side link hub as a base-end member and a tip-side link hub as a tip member are connected via three or more sets of four-bar chain link mechanisms. there is In the parallel link mechanism of Patent Literature 2, the attitude of the distal end member can be changed with respect to the proximal end member. The parallel link mechanism of Patent Document 2 is compact, yet capable of high-speed, high-precision operation over a wide operating range.

However, in the parallel link mechanism of Patent Document 2, the rotation radius of the movement path of the tip member changes depending on the position of the tip member, and the position of the center of rotation in the rotational movement of the tip member cannot be fixed. That is, when viewed from the proximal end member, the distal end member cannot move on a spherical surface having a constant radius from the fixed center of rotation, so there is a problem that it is difficult to visualize the movement of the distal end member. Furthermore, since the distal end member operates with two rotational degrees of freedom with respect to the proximal end member, there is also the problem that the rotational radius of the distal end member cannot be controlled independently of the rotational movement of the distal end member.

An object of the present invention is to provide a parallel link mechanism in which a tip member can move on a spherical surface having a constant radius from a fixed rotation center, and the rotation radius of the tip member can be controlled independently of the rotational movement. Another object is to provide a link actuating device.

A parallel linkage according to the present disclosure comprises a proximal member and three or more linkages. Three or more linkages are configured to connect the proximal and distal members. Three or more linkages can change the orientation of the distal member relative to the proximal member. Each of the three or more link mechanisms includes first through fourth link members. The first link member is rotatably connected to the proximal member at the first rotational pair. The second link member is rotatably connected to the first link member at the second rotational pair. The third link member is rotatably connected to the second link member at the third rotational pair. A fourth link member is rotatably connected to the third link member at a fourth rotational pair. The fourth link member is further configured to be rotatably connected to the tip member at a fifth rotational pair. In the three or more link mechanisms, the first central axis of the first rotating pair and the second central axis of the second rotating pair intersect at the spherical link center point. The fifth center axes of the fifth rotating pairs in each of the three or more link mechanisms overlap and intersect the spherical link center point.

A link actuating device according to the present disclosure includes the parallel link mechanism described above and an attitude control drive source. The attitude control drive source is installed in at least three of the three or more link mechanisms, and arbitrarily changes the attitude of the distal member with respect to the proximal member.

According to the above, the tip member can move on a spherical surface having a constant radius from the fixed rotation center, and the rotation radius of the tip member can be controlled independently of the rotational movement. Parallel link mechanism and link An actuator is obtained.

1 is a schematic perspective view showing the configuration of a parallel link mechanism according to Embodiment 1; FIG. FIG. 2 is a schematic front view of the parallel link mechanism shown in FIG. 1; FIG. 3 is a schematic cross-sectional view taken along line III-III in FIG. 2; FIG. 4 is a schematic cross-sectional view taken along line IV-IV in FIG. 3; It is a perspective schematic diagram which shows the state which changed the attitude|position of the tip member in the parallel link mechanism shown in FIG. FIG. 8 is a schematic cross-sectional view of a parallel link mechanism according to Embodiment 2; FIG. 7 is a schematic cross-sectional view along line segment VII-VII in FIG. 6; FIG. 11 is a schematic perspective view of a link actuating device according to Embodiment 3; FIG. 9 is a schematic cross-sectional view of the link actuating device shown in FIG. 8; FIG. 11 is a schematic perspective view showing a link actuating device according to Embodiment 4; FIG. 11 is a schematic perspective view showing a link actuating device according to Embodiment 5; FIG. 11 is a schematic perspective view showing the configuration of a parallel link mechanism according to Embodiment 6; 13 is a schematic cross-sectional view of the parallel link mechanism shown in FIG. 12; FIG. FIG. 12 is a schematic perspective view showing the configuration of a parallel link mechanism according to Embodiment 7;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings below, the same reference numbers are given to the same or corresponding parts, and the description thereof will not be repeated.

(Embodiment 1)
<Configuration of Parallel Link Mechanism>
FIG. 1 is a schematic perspective view showing the configuration of a parallel link mechanism according to Embodiment 1 of the present invention. 2 is a schematic front view of the parallel link mechanism shown in FIG. 1. FIG. FIG. 3 is a schematic cross-sectional view taken along line III-III in FIG. FIG. 4 is a schematic cross-sectional view taken along line IV-IV in FIG.

The parallel link mechanism 10 shown in FIGS. 1-4 comprises a proximal member 1, a distal member 8, and three link mechanisms 11. As shown in FIG. The proximal end member 1 is a plate-like body having a circular planar shape. In addition, the shape of the base end member 1 can be made into arbitrary shapes. For example, the planar shape of the proximal end member 1 may be polygonal such as quadrangular, triangular, elliptical, or semicircular. Also, the number of link mechanisms 11 may be 3 or more, and may be 4 or 5, for example.

The three link mechanisms 11 connect the proximal end member 1 and the distal end member 8 in a state in which the posture of the distal end member 8 with respect to the proximal end member 1 can be changed. Each of the three link mechanisms 11 includes first link members 4a, 4b, 4c, second link members 6a, 6b, 6c, third link members 7a, 7b, 7c and fourth link members 8a, 8b, 8c. . The first link members 4a, 4b, 4c are rotatably connected to the base end member 1 at the first rotational pair. Specifically, proximal connection portions 2 a , 2 b , and 2 c are provided on the outer peripheral portion of the proximal member 1 . Each of the base end connection portions 2a, 2b, and 2c includes a base portion 21 fixed to the surface of the base end member 1, and a shaft portion 22 formed to protrude from the base portion 21 to the outer peripheral side. The shaft portion 22 is inserted into the through holes 43 of the first link members 4a, 4b, 4c. Nuts 3a, 3b, and 3c, which are examples of fixing members, are fixed to the tip portions of the shaft portions 22 projecting from the through holes 43 of the first link members 4a, 4b, and 4c. The first link members 4 a , 4 b , 4 c are rotatable around the shaft portion 22 . A first rotational pair portion is configured by the shaft portion 22 and the portions of the first link members 4a, 4b, and 4c formed with the through holes 43 into which the shaft portions 22 are inserted.

The first link members 4a, 4b, and 4c are bar-shaped members extending in an arc shape. The through holes 43 are formed at one ends of the first link members 4a, 4b and 4c. As shown in FIG. 3, in a plan view from a direction perpendicular to the surface of the proximal member 1, the inner peripheral surfaces of the first link members 4a, 4b, and 4c are curved. The radius of curvature of the inner peripheral surface in plan view is smaller than the radius of curvature of the outer periphery of the proximal member 1 . The radius of curvature of the inner peripheral surface may be the same as the radius of curvature of the outer periphery of the proximal member 1, or may be larger than the radius of curvature of the outer periphery. Also, the shape of the first link members 4a, 4b, and 4c may be a shape other than an arc shape. For example, the shape of the first link members 4a, 4b, 4c may be a straight rod-like shape or a rod-like shape including a bent portion. As shown in FIG. 3, the first link members 4a, 4b, 4c are arranged outside the outer periphery of the base end member 1. As shown in FIG.

A shaft portion 42 is formed at the other end portion 41 of the first link members 4a, 4b, and 4c located opposite to the one end portion where the through hole 43 is formed. The shaft portion 42 is formed so as to extend outward from the outer periphery of the base end member 1 . The shaft portion 42 is formed on the outer peripheral side surface of the first link members 4a, 4b, 4c opposite to the inner peripheral side surface facing the base end member 1. As shown in FIG. The shaft portion 42 is inserted into the through holes 63 of the second link members 6a, 6b, 6c. Nuts 5a, 5b, and 5c, which are examples of fixing members, are fixed to the tip portions of the shaft portions 42 protruding from the through holes 63 of the second link members 6a, 6b, and 6c. The second link members 6 a , 6 b , 6 c are rotatable around the shaft portion 42 . A second rotational pair portion is constituted by the shaft portion 42 and the portions of the second link members 6a, 6b, and 6c in which the through holes 63 into which the shaft portions 42 are inserted are formed. That is, the second link members 6a, 6b, 6c are rotatably connected to the first link members 4a, 4b, 4c at the second rotational pair.

The central axes 15a, 15b, and 15c of the shaft portion 22 in the base end connection portions 2a, 2b, and 2c correspond to the central axes of the first rotating pair portion. The central axes 16a, 16b, 16c of the shaft portions 42 at the other end portions 41 of the first link members 4a, 4b, 4c correspond to the central axes of the second rotating pair portions. As shown in FIGS. 1 and 3, the central axes 15a, 15b, 15c of the shaft portion 22 and the central axes 16a, 16b, 16c of the shaft portion 42 intersect at the center point 30 of the spherical link. This intersection is a necessary condition. The arrangement of the first and second rotational pair portions can be changed arbitrarily.

The second link members 6a, 6b, 6c are rod-shaped members extending linearly. The through hole 63 is formed at one end of each of the second link members 6a, 6b, 6c. The shape of the second link members 6a, 6b, 6c may be any shape other than a linearly extending rod shape. For example, the second link members 6a, 6b, 6c may be rod-shaped bodies extending in an arc shape. As shown in FIGS. 1 and 3, the first link members 4a, 4b, 4c are arranged to extend along the surface of the proximal member 1, and the second link members 6a, 6b, 6c are arranged to extend along the surface of the proximal member 1. It is arranged outside the outer circumference of the member 1 . The second link members 6 a , 6 b , 6 c may be arranged at positions overlapping the outer periphery of the proximal member 1 or may be arranged inside the outer periphery of the proximal member 1 .

A concave portion for receiving one end of each of the third link members 7a, 7b, 7c is formed at the other end of the second link members 6a, 6b, 6c opposite to the one end where the through hole 63 is formed. It is A through hole is formed at a position facing the recess in the other end of the second link members 6a, 6b, 6c. Through holes are also formed in one end portions of the third link members 7a, 7b, and 7c. The through holes at the other ends of the second link members 6a, 6b, 6c and the through holes 73 at the one ends of the third link members 7a, 7b, 7c are arranged linearly. Connecting members 13a, 13b, 13c are inserted into the through holes at the other ends of the second link members 6a, 6b, 6c and the through holes 73 at the one ends of the third link members 7a, 7b, 7c. . The connecting members 13a, 13b, 13c connect the second link members 6a, 6b, 6c and the third link members 7a, 7b, 7c in a relatively rotatable state. The connecting members 13a, 13b, 13c are, for example, bolts and nuts. The connecting members 13a, 13b, 13c, the other end portions of the second link members 6a, 6b, 6c, and the one end portions of the third link members 7a, 7b, 7c constitute a third rotational pair portion. That is, the second link members 6a, 6b, 6c and the third link members 7a, 7b, 7c are rotatably connected at the third rotational pair.

The central shafts 17a, 17b, 17c of the connecting members 13a, 13b, 13c correspond to the central shafts of the third rotational pair. The central axes 17a, 17b and 17c extend in directions perpendicular to the central axes 16a, 16b and 16c, respectively.

The third link members 7a, 7b, and 7c are rod-shaped members extending linearly. The through hole 73 is formed at one end of each of the third link members 7a, 7b, 7c. The shape of the third link members 7a, 7b, and 7c may be any shape other than a linearly extending rod shape. For example, the third link members 7a, 7b, and 7c may be rods extending in an arc shape.

A through hole 74 is formed in the other end of the third link members 7a, 7b, 7c located opposite to the one end where the through hole 73 is formed. The fourth link members 8a, 8b, 8c are formed with recesses for receiving the other ends of the third link members 7a, 7b, 7c. A wall portion 83 of each of the fourth link members 8a, 8b, 8c facing the concave portion is formed with a through hole communicating with the concave portion. The through-holes 74 at the other ends of the third link members 7a, 7b, 7c and the through-holes formed in the wall portions 83 of the fourth link members 8a, 8b, 8c are arranged in a straight line. Connecting members 14a, 14b, 14c are inserted into the through holes 74 at the other ends of the third link members 7a, 7b, 7c and the through holes in the wall portions 83 of the fourth link members 8a, 8b, 8c. . The connecting members 14a, 14b, 14c connect the third link members 7a, 7b, 7c and the fourth link members 8a, 8b, 8c in a relatively rotatable state. The connecting members 14a, 14b, 14c are, for example, bolts and nuts. The connecting members 14a, 14b, 14c, the other end portions of the third link members 7a, 7b, 7c, and the wall portions 83 of the fourth link members 8a, 8b, 8c form a fourth rotational pair portion. That is, the third link members 7a, 7b, 7c and the fourth link members 8a, 8b, 8c are rotatably connected at the fourth rotational pair portion.

The central shafts 18a, 18b, 18c of the connecting members 14a, 14b, 14c correspond to the central shafts of the fourth rotational pair portion. The central axes 18a, 18b, 18c extend parallel to the central axes 17a, 17b, 17c, respectively.

The fourth link members 8a, 8b, 8c include base portions 81a-81c connected to the wall portion 83, respectively. The planar shape of the base portions 81a to 81c is circular. A central shaft 82 is provided in the center of the base portion 81a as shown in FIG. The base portion 81b of the fourth link member 8b is arranged so as to overlap the base portion 81a. A through hole is formed in the center of the base portion 81b. The base portion 81c of the fourth link member 8c is arranged so as to overlap the base portion 81b. A through hole is formed in the center of the base portion 81c. The base portions 81b and 81c are stacked on the base portion 81a with the central shaft 82 inserted into each through hole. A nut 9 as a fixing member is installed at the tip of the central shaft 82 . The fourth link members 8a, 8b, 8c are rotatable around the central axis 82 independently of each other. In the parallel link mechanism 10 shown in FIGS. 1 to 4, the center shaft 82 or the base portions 81a to 81c of the stacked fourth link members 8a, 8b, 8c can be regarded as the tip member 8. As shown in FIG. As the tip member, another member may be connected to either the central shaft 82 or the base portions 81a to 81c. In the configuration as described above, the base portions 81a to 81c, the central shaft 82 and the nut 9 constitute the fifth rotating pair portion. As can be seen from FIG. 1, the fifth central shafts 19 of the fifth rotating pair portions of the three link mechanisms 11 are arranged so as to overlap. That is, the fifth rotating pair portions of the plurality of link mechanisms 11 are arranged so as to overlap at one place. As the central shaft 82, a bolt or the like, which is a separate member from the base 81a, may be used. In this case, a through hole for inserting the bolt is formed in the central portion of the base portion 81a.

In the fourth link members 8a, 8b, 8c, the fourth central shafts 18a, 18b, 18c of the fourth rotational pair portion and the fifth central shaft 19 of the fifth rotational pair portion are twisted. More specifically, the fourth central shafts 18a, 18b, 18c of the fourth rotational joint portion and the fifth central shaft 19 of the fifth rotational joint portion extend in directions perpendicular to each other.

As shown in FIGS. 1 and 3, the first central shafts 15a, 15b, 15c of the first rotational joint portion and the second central shafts 16a, 16b, 16c of the second rotational joint portion are located at the center point 30 of the spherical link. intersect. Further, as shown in FIG. 4 , the fifth central shafts 19 of the fifth rotational pairs of the link mechanisms 11 overlap and intersect the spherical link center point 30 . Note that the arrangement of the paired portions can be arbitrarily set as long as the above relationship is satisfied.

<Operation of Parallel Link Mechanism>
FIG. 5 is a schematic perspective view showing a state in which the posture of the tip member is changed in the parallel link mechanism shown in FIG. 1; As shown in FIG. 5, the position of the tip member 8 can be arbitrarily changed by changing the rotation angles around the first central axes 15a, 15b, and 15c in the first rotation pairs of the first link members 4a, 4b, and 4c. can be changed to In FIG. 5, by relatively increasing the rotation angle of the first link member 4b around the first central axis 15b, the fourth link member 8b side of the tip member 8 is lifted upward, and when viewed from the tip member center 31 The entire tip member 8 has moved to the side opposite to the side where the fourth link member 8b is located.

In the parallel link mechanism 10 shown in FIGS. 1 to 5, the end member 8 moves on a spherical surface centered on the spherical link center point 30 by adopting the configuration described above. That is, the posture of the tip member 8 can be represented by three-dimensional polar coordinates (r, θ, φ) with the spherical link center point 30 as the origin, as shown in FIG. The bending angle θ referred to here means that a line drawn vertically from the tip member center 31 is the first rotation pair portion of the first rotation pair portion, which is the connection portion between the base end member 1 and the first link members 4a, 4b, and 4c. It is an angle formed by a straight line passing through a point intersecting a plane including the central axes 15a, 15b, and 15c and the spherical link central point 30, and the fifth central axis 19, which is the central axis of the tip member. The turning angle φ is defined by a straight line passing through a point where a line drawn vertically from the tip member center 31 intersects a plane containing the first center axes 15a, 15b, and 15c and the spherical link center point 30, and the first link This is the angle formed between the mechanism 11 and the first center axis 15a of the first rotating pair. The center-to-center distance r is the distance between the spherical link center point 30 and the tip member center 31 .

<Effect>
A parallel linkage 10 according to the present disclosure comprises a proximal member 1 and three or more linkages 11 . Three or more linkages 11 are configured to connect the proximal member 1 and the distal member 8 . The three or more link mechanisms 11 can change the attitude of the distal end member 8 with respect to the proximal end member 1 . Each of the three or more link mechanisms 11 includes first to fourth link members. The first link members 4a, 4b, 4c are rotatably connected to the base end member 1 at the first rotational pair. The second link members 6a, 6b, 6c are rotatably connected to the first link members 4a, 4b, 4c at second rotational pairs. The third link members 7a, 7b, 7c are rotatably connected to the second link members 6a, 6b, 6c at third rotational pairs. The fourth link members 8a, 8b, 8c are rotatably connected to the third link members 7a, 7b, 7c at the fourth rotational pair. The fourth link members 8a, 8b, 8c are further configured to be rotatably connected to the tip member 8 at a fifth rotational pair. In the three or more link mechanisms 11, the first central shafts 15a, 15b, 15c of the first rotational pair and the second central shafts 16a, 16b, 16c of the second rotational pair intersect at the spherical link center point 30. . The fifth central axis 19 of the fifth rotational pair portion in each of the three or more link mechanisms 11 overlaps and intersects the spherical link center point 30 .

With this configuration, each of the three or more link mechanisms 11 has a five-bar link structure having the first to fifth rotational pairs. It can be moved with a total of three degrees of freedom: two degrees of freedom in rotation about the central point 30 and one degree of freedom in the direction along the fifth central axis 19 . Therefore, the distal end member 8 can be moved relative to the proximal end member 1 along the spherical surface centered on the spherical link center point 30, and the fifth center can be moved independently of the movement along the spherical surface. Movement along the axis 19 is also possible. As a result, the tip member 8 can be moved along the spherical surface, and the radius of the spherical surface along which the tip member 8 moves can be adjusted. The movable range of the member 8 can be increased. Here, the fourth link members 8a, 8b, 8c are configured to be rotatably connected to the distal end member 8 at the fifth rotational pair portion, which means that the fourth link members 8a, 8b, 8c It means that there is a portion that can be connected to a tip member as a separate member, and includes the case where a part of the fourth link members 8a, 8b, 8c functions as the tip member.

In the parallel link mechanism 10, the third central shafts 17a, 17b, 17c of the third rotational joint portion and the fourth central shafts 18a, 18b, 18c of the fourth rotational joint portion extend parallel to each other, and the second central shaft It may extend in a direction intersecting 16a, 16b, 16c. In this case, the third central shafts 17a, 17b, 17c of the third rotational pair portion and the fourth central shafts 18a, 18b, 18c of the fourth rotational pair portion in the third link members 7a, 7b, 7c constituting the link mechanism 11 are parallel to each other, the configuration of the third link members 7a, 7b, 7c can be simplified.

In the parallel link mechanism 10, the third center shafts 17a, 17b, 17c and the fourth center shafts 18a, 18b, 18c may extend in a direction orthogonal to the second center shafts 16a, 16b, 16c. In this case, when the parallel link mechanism 10 is manufactured, a step of connecting the second link members 6a, 6b, 6c and the first link members 4a, 4b, 4c and a step of connecting the second link members 6a, 6b, 6c and the third link member 7a are performed. , 7b and 7c can be assembled with good workability.

In the parallel link mechanism 10 described above, the second rotational pair portion may be located outside the outer circumference of the proximal member 1 when the proximal member 1 is viewed from the distal member 8 side. In this case, the influence of the base end member 1 on the movable range of the second rotation pair portion can be reduced compared to the case where the second rotation pair portion is located inside the outer periphery of the base end member 1 . For example, when viewed from the lateral direction along the first surface of the proximal member 1 on the side of the distal member 8, the range of motion of the second rotational pair is reduced to the second surface of the proximal member 1 on the side opposite to the first surface. It can be extended to the surface side. At this time, it is preferable that the first link members 4a, 4b, and 4c are also arranged outside the outer periphery of the proximal member 1. As shown in FIG.

(Embodiment 2)
<Configuration of Parallel Link Mechanism>
FIG. 6 is a schematic cross-sectional view of a parallel link mechanism according to Embodiment 2. FIG. FIG. 7 is a schematic cross-sectional view taken along line VII-VII in FIG. 6 corresponds to FIG. 3, and FIG. 7 corresponds to FIG.

The parallel link mechanism shown in FIGS. 6 and 7 basically has the same configuration as the parallel link mechanism 10 shown in FIGS. It differs from the parallel link mechanism shown in FIGS. 1 to 5 in that bearings 25 to 29 are installed as means. In FIGS. 6 and 7, the bearings 25 to 29 are installed in all the rotating pairs, but the bearings may be installed in at least one of the first to fifth rotating pairs. .

Specifically, as shown in FIG. 6, in the first rotating pair portion, bearings 25 are arranged between the shaft portions 22 of the base end connecting portions 2a, 2b, 2c and the first link members 4a, 4b, 4c. It is As the bearing 25, for example, a rolling bearing such as a ball bearing can be used. For example, the outer rings of the bearings 25 may be fixed to the first link members 4a, 4b, 4c. Moreover, the inner ring of the bearing 25 connected to the shaft portion 22 may be fixed while being sandwiched between the nuts 3a, 3b, 3c and the base portion 21. As shown in FIG.

In the second rotational pair portion, bearings 26 are arranged between the shaft portions 42 of the first link members 4a, 4b, 4c and the second link members 6a, 6b, 6c. For example, the outer ring of the bearing 26 may be fixed on the side of the second link members 6a, 6b, 6c. Further, the inner ring of the bearing 26 connected to the shaft portion 42 may be fixed while being sandwiched between the nuts 5a, 5b, 5c and the first link members 4a, 4b, 4c.

In the third rotational pair portion, bearings 27 are arranged between the connecting members 13a, 13b, 13c (see FIG. 2) and the third link members 7a, 7b, 7c (see FIG. 2), as shown in FIG. there is For example, the outer ring of the bearing 27 may be fixed on the side of the third link members 7a, 7b, 7c. Any method can be used to fix the outer ring of the bearing 27 to the third link members 7a, 7b, and 7c. For example, holes for inserting the outer rings may be formed in the third link members 7a, 7b, and 7c, and the outer rings may be fixed to the holes by press-fitting the outer rings into the holes. Any method can be used to fix the inner ring of the bearing 27 to the connecting members 13a, 13b, and 13c. For example, consider a case where a rod-shaped body such as a full thread and a set of washers and a set of nuts arranged at both ends of the rod-shaped body are used as the connecting members 13a, 13b, and 13c. In this case, through holes at one ends of the second link members 6a, 6b, 6c and openings of the inner rings of the bearings 27 arranged inside the through holes at one ends of the third link members 7a, 7b, 7c A rod-shaped body is arranged so as to pass through. Place washers and nuts on both ends of the bar. By tightening the nuts, one ends of the second link members 6a, 6b, 6c and the washers are pressed against the inner ring of the bearing 27 to apply preload to the inner ring. As a result, the inner ring of the bearing 27 is fixed to the second link members 6a, 6b, 6c via the connecting members 13a, 13b, 13c.

In the fourth rotational pair portion, bearings 28 are arranged between the connecting members 14a, 14b, 14c (see FIG. 2) and the third link members 7a, 7b, 7c (see FIG. 2), as shown in FIG. there is For example, the outer ring of the bearing 28 may be fixed on the side of the third link members 7a, 7b, 7c. Any method can be used to fix the inner ring of the bearing 28 to the connecting members 14a, 14b, and 14c. good.

A bearing 29 is arranged between the central shaft 82 and the base members 81b and 81c in the fifth rotational pair portion. For example, the outer ring of the bearing 29 may be fixed to the base members 81b, 81c. Moreover, the inner ring of the bearing 26 connected to the central shaft 82 may be fixed while being sandwiched between the nut 9 and the base member 81a. In FIGS. 6 and 7, the bearings 25 to 29 are used as the rotational resistance reducing means, but members other than the bearings may be used as long as the rotational resistance can be reduced.

<Effect>
In the above parallel link mechanism, at least one of the first to fifth rotational pairs may include bearings 25-29. In this case, it is possible to smoothen the motion of the rotating pair portion in which the bearings 25 to 29 are installed, and to improve the positioning accuracy of the tip end member 8 . In addition, by installing the bearings 25 to 29, it is possible to suppress heat generation in the rotating pair portion by reducing the friction torque of the rotating pair portion where the bearings are installed, and as a result, the life of the rotating pair portion can be extended. can be extended. Furthermore, by installing the bearings 25 to 29, rattling during operation of the rotating pair can be suppressed more than when the bearings 25 to 29 are not used.

(Embodiment 3)
<Configuration of Link Actuator>
FIG. 8 is a schematic perspective view of a link actuating device according to Embodiment 3. FIG. 9 is a schematic cross-sectional view of the link actuating device shown in FIG. 8. FIG. 8 corresponds to FIG. 1, and FIG. 9 corresponds to FIG.

The link actuating device shown in FIGS. 8 and 9 includes the parallel link mechanism 10 shown in FIGS. 1 to 5 and attitude control drive sources 35a, 35b, and 35c. Attitude control drive sources 35 a , 35 b , 35 c are installed in all three link mechanisms 11 . The attitude control drive sources 35a, 35b, and 35c change the rotation angles of the first link members 4a, 4b, and 4c about the first central axes 15a, 15b, and 15c, so that the tip end member 8 is rotated with respect to the base end member 1. Change your posture at will.

As shown in FIGS. 8 and 9, the attitude control drive sources 35a, 35b, and 35c are connected to the base end member 1 by being fixed to fixing portions 36a, 36b, and 36c, respectively. The fixed portions 36 a , 36 b , 36 c are installed on the outer peripheral portion of the surface of the base end member 1 . The fixing portions 36a, 36b, and 36c may have any shape, but are plate-like, for example.

The attitude control drive sources 35a, 35b, and 35c may have any configuration, such as an electric motor, as long as they can generate rotational driving force. The attitude control drive sources 35a, 35b, and 35c each include a rotatable rotary shaft 37. As shown in FIG. A rotary shaft 37 is inserted into through holes 43 of the first link members 4a, 4b, 4c and fixed by nuts 3a, 3b, 3c. That is, the first link members 4a, 4b, and 4c are fixed to the rotating shaft 37. As shown in FIG. Rotation of the rotary shaft 37 causes the first link members 4a, 4b, 4c to rotate around the first central shafts 15a, 15b, 15c. Here, the first central axes 15a, 15b, 15c are central axes of the rotating shaft 37 as shown in FIG.

The attitude control drive sources 35a, 35b, and 35c are arranged at positions overlapping the first central shafts 15a, 15b, and 15c. The attitude control drive sources 35a, 35b, and 35c are arranged on the front surface side of the base end member 1 on the side of the tip end member 8 so as to protrude outward from the outer circumference of the base end member 1. As shown in FIG.

With such a configuration, the posture of the distal end member 8 with respect to the proximal end member 1 can be uniquely determined by the state of each link mechanism 11 (see FIG. 1). That is, by controlling the posture of the first link members 4a, 4b, and 4c with respect to the base end member 1, or the rotation angles of the first link members 4a, 4b, and 4c around the first central axes 15a, 15b, and 15c, The posture of the tip member 8 can be controlled.

When three or more link mechanisms 11 (see FIG. 1) are installed in the link actuating device, at least three link mechanisms among the three or more link mechanisms 11 are equipped with attitude control drive sources 35a, 35b, and 35c. should be set.

<Effect>
A link actuating device according to the present disclosure includes the parallel link mechanism 10 and attitude control drive sources 35a, 35b, and 35c. The attitude control drive sources 35a, 35b, and 35c are installed in at least three of the three or more link mechanisms 11, and arbitrarily change the attitude of the distal member 8 with respect to the proximal member 1. FIG.

In this case, at least three attitude control drive sources 35a, 35b, and 35c individually control the link mechanism 11, so that the distal end member 8 can be operated in a wide range and precisely. Moreover, by using the parallel link mechanism 10 as described above, a lightweight and compact link actuating device can be realized.

(Embodiment 4)
<Configuration of Link Actuator>
FIG. 10 is a schematic perspective view showing a link actuating device according to Embodiment 4. FIG. The link actuating device shown in FIG. 10 has basically the same configuration as the link differential device shown in FIGS. It differs from the link actuating device shown in FIG. In the link actuating device shown in FIG. 10, attitude control drive sources 35a, 35b, and 35c are arranged on the surface of the base end member 1 on the side of the tip member 8 and inside the outer circumference of the base end member 1. . Fixing portions 36a, 36b, and 36c for fixing the attitude control drive sources 35a, 35b, and 35c are fixed to the base end member 1 on the inner peripheral side of the first link members 4a, 4b, and 4c. Attitude control drive sources 35a, 35b, and 35c are arranged on the inner circumference side of the fixed portions 36a, 36b, and 36c.

<Effect>
With such a configuration, the same effects as those of the link actuating device shown in FIGS. 8 and 9 can be obtained. Furthermore, since the attitude control drive sources 35a, 35b, and 35c are arranged inside the outer circumference of the base end member 1, the area occupied by the device can be made smaller than that of the link actuating device shown in FIGS.

(Embodiment 5)
<Configuration of Link Actuator>
11 is a schematic perspective view showing a link actuating device according to Embodiment 5. FIG. The link actuating device shown in FIG. 11 basically has the same configuration as the link differential device shown in FIG. , 35b, 35c and the first link members 4a, 4b, 4c differ from the link actuating device shown in FIG. In the link actuating device shown in FIG. 11, attitude control drive sources 35a, 35b, and 35c are arranged on the rear surface side of the base end member 1. As shown in FIG. That is, the attitude control drive sources 35a, 35b, and 35c are connected to the rear surface of the proximal member 1 opposite to the surface facing the distal member 8. As shown in FIG. The method of fixing the attitude control drive sources 35a, 35b, and 35c to the rear surface of the base end member 1 is basically the same as that of the link actuating device shown in FIG. Taking the posture control drive source 35a as an example, the posture control drive source 35a is connected to a fixing portion 36a fixed to the rear surface of the base end member 1. As shown in FIG. Gears 38 are fixed to the rotating shafts 37 of the attitude control drive sources 35a, 35b, and 35c. A gear 39 is installed so as to mesh with the gear 38 . The gear 39 is rotatably installed on the shaft portion 22 of the proximal connection portions 2a, 2b, and 2c on the surface side of the proximal member 1. As shown in FIG. The gear 39 is fixed to the first link members 4a, 4b, 4c. In this way, the rotating shafts 37 of the attitude control drive sources 35a, 35b, and 35c are rotated, so that the first link members 4a, 4b, and 4c are connected to the first center shafts 15a, 15b, 4c through the gears 38, 39. 15c can be rotated.

<Effect>
With such a configuration, the same effects as those of the link actuating device shown in FIGS. 8 and 9 can be obtained. Furthermore, since the attitude control drive sources 35a, 35b, and 35c are arranged on the back side of the base end member 1, the attitude control drive sources 35a, 35b, and 35c are used to operate the link mechanism 11 (see FIG. 1). You can avoid getting in the way. In addition, since the attitude control drive sources 35a, 35b, and 35c are arranged at positions overlapping the base end member 1 in plan view, the area occupied by the device can be made smaller than that of the link actuating device shown in FIGS.

(Embodiment 6)
<Configuration of Parallel Link Mechanism>
FIG. 12 is a schematic perspective view showing the configuration of a parallel link mechanism according to Embodiment 6. FIG. 13 is a schematic cross-sectional view of the parallel link mechanism shown in FIG. 12. FIG. 12 corresponds to FIG. 1, and FIG. 13 corresponds to FIG. The parallel link mechanisms shown in FIGS. 12 and 13 basically have the same configuration as the parallel link mechanisms shown in FIGS. 1 to 5, but as shown in FIG. The distances L1 to L3 from 2c to the spherical link center point are different from each other. Specifically, the distance L1 from the base end connecting portion 2a to the spherical link center point 30 is the shortest. A distance L2 from the base end connecting portion 2b to the spherical link center point 30 is greater than the distance L1. A distance L3 from the base end connecting portion 2c to the spherical link center point 30 is greater than the distance L1 and smaller than the distance L2. In the plan view shown in FIG. 13, the first link member 4a is arranged at a position overlapping the surface of the base end member 1. As shown in FIG. The other first link member 4b is arranged outside the outer periphery on the surface of the base end member 1. As shown in FIG. The other first link member 4c is arranged such that its outer peripheral portion substantially overlaps with the outer peripheral portion of the surface of the base end member 1 in plan view.

<Effect>
Even if the distances L1 to L3 from the base end connecting portions 2a, 2b, 2c to the center point of the spherical link are different in this way, the same effect as the parallel link mechanism shown in FIGS. 1 to 5 can be obtained. That is, the first central shafts 15a, 15b, 15c of the first rotational joint portion and the second central shafts 16a, 16b, 16c of the second rotational joint portion intersect at the spherical link center point 30, and the three link mechanisms 11 (see FIG. 1) of each of the fifth rotational pair portions 19 (see FIG. 2) overlap and intersect with the spherical link center point 30, the conditions shown in FIGS. Similar to the parallel link mechanism described above, the tip member 8 can be moved relative to the base end member 1 along a spherical surface centered on the spherical link center point 30, and can be moved independently of the movement along the spherical surface. can be moved in the direction along the fifth central axis 19 as well.

(Embodiment 7)
<Configuration of Parallel Link Mechanism>
14 is a schematic perspective view showing the configuration of a parallel link mechanism according to Embodiment 7. FIG. The parallel link mechanism shown in FIG. 14 basically has the same configuration as the parallel link mechanisms shown in FIGS. The relative arrangement with the first link members 4a, 4b, 4c is different. In the parallel link mechanism 10 shown in FIG. 14, an opening 45 is formed in the proximal member 1 . When the base end member 1 is viewed from the side of the distal end member 8 , the first rotating pair portion and the second rotating pair portion are located inside the opening 45 . Further, the base end connecting portions 2a, 2b, 2c are connected to the base end member 1, and are arranged on the outer peripheral side from the first link members 4a, 4b, 4c.

<Effect>
With the configuration as described above, the base end member 1 does not exist at a position overlapping the second rotating pair portion in the plan view. Therefore, when viewed from the lateral direction along the first surface on the side of the distal end member 8 in the proximal member 1, the range of motion of the second rotating pair portion is the first surface on the side opposite to the first surface in the proximal member 1. 2 It can be extended to the front side (back side). As a result, the tip member 8 can be moved to a position close to the spherical link center point 30 .

It should be noted that the attitude control drive sources 35a, 35b, and 35c shown in any one of FIGS. 8 to 11 may be applied to the parallel link mechanism in each of the above-described embodiments to form a link actuating device. . In each embodiment, the number of link mechanisms 11 is 3, but the number of link mechanisms 11 may be any number greater than or equal to 4, such as 5, 6, 8, and the like.

Each embodiment disclosed this time should be considered as an illustration and not restrictive in all respects. The scope of the present invention is indicated by the scope of the claims rather than the above description, and is intended to include all modifications within the meaning and range of equivalents of the scope of the claims.

1 base end member 2a, 2b, 2c base end connection portion 3a, 3b, 3c, 5a, 5b, 5c, 9 nut 4a, 4b, 4c first link member 6a, 6b, 6c second link member, 7a, 7b, 7c Third link member 8 Tip member 8a, 8b, 8c Fourth link member 10 Parallel link mechanism 11 Link mechanism 13a, 13b, 13c, 14a, 14b, 14c Connecting member 15a, 15b , 15c first center shaft 16a, 16b, 16c second center shaft 17a, 17b, 17c third center shaft 18a, 18b, 18c fourth center shaft 19 fifth center shaft 21 base portion 22, 42 Axial portion 25, 26, 27, 28, 29 Bearing 30 Spherical link center point 31 Tip member center 35a, 35b, 35c Attitude control drive source 36a, 36b, 36c Fixed portion 37 Rotating shaft 38, 39 Gear 41 Other end 43, 63, 73, 74 Through hole 45 Opening 81a, 81b, 81c Base member 82 Center shaft 83 Wall.

Claims (7)

a proximal member;
and three or more link mechanisms,
the three or more link mechanisms are configured to connect the proximal member and the distal member;
The three or more link mechanisms are capable of changing the posture of the tip member with respect to the base end member,
each of the three or more link mechanisms,
a first link member rotatably connected to the base end member at a first rotational pair;
a second link member rotatably connected to the first link member at a second rotational pair;
a third link member rotatably connected to the second link member at a third rotational pair;
a fourth link member rotatably connected to the third link member at a fourth rotational pair;
The fourth link member is configured to be rotatably connected to the tip member at a fifth rotational pair,
In the three or more link mechanisms, the first central axis of the first rotational joint portion and the second central axis of the second rotational joint portion intersect at a spherical link center point,
A parallel link mechanism, wherein the fifth center axes of the fifth rotating pair portions of the three or more link mechanisms overlap and intersect with the spherical link center point. 2. The parallel according to claim 1, wherein a third central axis of said third rotational pair portion and a fourth central axis of said fourth rotational pair portion extend parallel to each other and extend in a direction intersecting said second central axis. link mechanism. 3. The parallel link mechanism according to claim 2, wherein said third central axis and said fourth central axis extend in a direction orthogonal to said second central axis. 4. The parallel link mechanism according to any one of claims 1 to 3, wherein at least one of said first to fifth rotational pairs includes a bearing. 5. The second rotating pair according to any one of claims 1 to 4, wherein when the base end member is viewed in plan from the tip member side, the second rotating pair portion is positioned outside the outer circumference of the base end member. Parallel link mechanism. An opening is formed in the proximal member,
The parallel link mechanism according to any one of claims 1 to 4, wherein the second rotating pair is located inside the opening when the proximal member is viewed from the distal member side. . A parallel link mechanism according to any one of claims 1 to 6;
A link actuating device, comprising an attitude control drive source installed in at least three link mechanisms out of the three or more link mechanisms and arbitrarily changing the attitude of the tip member with respect to the base end member.

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