JP5344402B2 - 3-DOF active rotary joint - Google Patents

Abstract

An active rotation articulation with three degrees of freedom is provided with a rotating body (20) whereto a first link (10a) is connected; rotating actuators (100x, 100y, 100z) for the X-axis, the Y-axis, and the Z-axis, said rotating actuators (100x, 100y, 100z) being disposed in such a way that output shafts (101x, 101y, 101z) are directed toward the center of the rotating body (20) and intersect one another at right angles, resulting in the rotating body (20) being made to rotate; and movable bodies (110x, 110y, 110z) which support the output shafts (101x, 101y, 101z) of the rotating actuators (100x, 100y, 100z) at positions where the output shafts (101x, 101y, 101z) are connected to the rotating body (20), and each of which allows the rotating body (20) to rotate about the other two unrelevant axes. The first link (10a) is connected to the rotating body (20) at a position approximately equidistant from the output shafts (101x, 101y, 101z). Therefore, it is possible to miniaturize and lighten the active rotation articulation with three degrees of freedom and to dispose the rotating actuators in a well-balanced way, thereby improving the dynamic properties between a pair of links.

Description

  The present invention relates to a three-degree-of-freedom active rotary joint that enables arbitrary rotational relative motion in a direction of three degrees of freedom between two links.

  In recent years, robot technology has been applied to various fields, for example, the medical field. In robots, it is necessary to perform functions similar to the functions of human hands, feet, heads, etc., and joints that can be actively rotated with three degrees of freedom are required.

  Generally, when an object can be rotated around three axes orthogonal to each other at the same time, the object has three degrees of freedom of rotation. For example, the human neck can move back and forth, right and left, and rotate left and right, and has three degrees of freedom.

  When an arbitrary rotational relative motion in the direction of three degrees of freedom is possible between two links by a joint that connects two links, this joint is referred to as a three-degree-of-freedom rotational joint. In particular, an object that can be actively operated by an actuator is called an active joint, and an object that cannot generate a driving force is called a passive joint.

  Conventionally, as the 3-degree-of-freedom active rotary joint, there is a 3-degree-of-freedom active rotary joint disclosed in Patent Document 1 previously filed by the present applicant. This three-degree-of-freedom active rotary joint includes three hollow shaft rotary motors for X-axis, Y-axis, and Z-axis, and the output shaft of each hollow-shaft rotary motor is coupled to a rotating body. Each of the hollow shaft rotary motors is supported by a support so as to restrict the rotation of each output shaft about the axis and allow rotation about other two orthogonal axes. Therefore, by rotating one of the three hollow shaft rotary motors, the rotating body rotates around the output shaft of one hollow shaft rotary motor. Similarly, by rotating the other two hollow shaft rotary motors, it is possible to arbitrarily rotate and move in the direction of three degrees of freedom between the two links.

JP 2008-44089 A

  However, since the three-degree-of-freedom active rotary joint disclosed in Patent Document 1 uses a relatively large and heavy hollow shaft rotary motor, the three-degree-of-freedom active rotary joint itself is enlarged and its size is increased. There is a problem that the dynamic characteristics of the link are affected by the weight. Further, in the three-degree-of-freedom active rotary joint disclosed in Patent Document 1, one of the pair of links protrudes from the rear end of the Z-axis hollow shaft rotary motor and is coaxially fixed to the output shaft. ing. Further, the X-axis hollow shaft rotary motor and the Y-axis hollow shaft rotary motor are arranged orthogonal to each other on the side of the rotating body. Therefore, since each hollow shaft rotary motor is biased with respect to the rotating body, there is a problem of affecting the dynamic characteristics of the link of the three-degree-of-freedom active rotary joint.

  The present invention has been made in view of the above-described problems. By reducing the size and weight of the three-degree-of-freedom active rotary joint and arranging the rotary actuators in a well-balanced manner, the movement between the pair of links is achieved. An object of the present invention is to provide a three-degree-of-freedom active rotary joint that improves characteristics.

The present invention is a three-degree-of-freedom active rotary joint provided between a pair of links, and a rotary body to which one of the pair of links is connected, and each output shaft is directed to the center of the rotary body. The X-axis, Y-axis, and Z-axis rotary actuators that are arranged so as to be orthogonal to each other and that rotate the rotary body, and the output shaft of the X-axis rotary actuator are coupled to the rotary body. A movable body that supports and allows rotation of the rotating body around the Y and Z axes, and an output shaft of the rotary actuator for the Y axis is supported at a position where it is coupled to the rotating body, and the X axis of the rotating body And a movable body that allows rotation about the Z-axis, and an output shaft of the Z-axis rotary actuator that is supported at a position where it is coupled to the rotary body, and allows rotation of the rotary body about the X-axis and Y-axis. OK Comprising a body, said one of the link with respect to the rotating body, characterized in that it is connected substantially to the position of the same distance from the respective output shaft.
The present invention is a three-degree-of-freedom active rotary joint provided between a pair of links, and a rotary body to which one of the pair of links is connected, and each output shaft is directed to the center of the rotary body. The X-axis, Y-axis, and Z-axis rotary actuators that are arranged so as to be orthogonal to each other and that rotate the rotary body, and are coupled to the output shaft of the X-axis rotary actuator via the shaft body A rotating body that rotates the rotating body around the X axis and allows the rotating body to rotate around the Y axis and the Z axis, and an output shaft of the rotary actuator for the Y axis, are coupled via the shaft body. The rotating body is coupled to a movable body that rotates the rotating body around the Y-axis and allows the rotating body to rotate around the X-axis and the Z-axis, and an output shaft of the rotary actuator for the Z-axis. Rotate body around Z axis And a movable body that allows the rotating body to rotate about the X axis and the Y axis, and the one link is connected to the rotating body at a position substantially the same distance from each shaft body. It is characterized by being.

  According to the present invention, the dynamic characteristics between the pair of links can be improved by arranging the rotary actuators in a balanced manner.

It is a perspective view which shows the 3-degree-of-freedom active rotary joint which concerns on 1st Embodiment. It is a partially exploded perspective view of a 3-DOF active rotary joint. It is a figure which shows the structure of a rotating ball receiver. It is sectional drawing of a rotation ball receiver. It is a figure which shows the structure of another rotating ball receiver. It is a figure which shows the structure of a slider support body. It is a figure which shows the structure of a slider support body. It is a figure which shows operation | movement of a 3-DOF active rotary joint. It is a figure which shows operation | movement of a 3-DOF active rotary joint. It is a figure which shows operation | movement of a 3-DOF active rotary joint. It is a perspective view which shows the 3 degrees-of-freedom active rotary joint which concerns on 2nd Embodiment. It is a figure which shows the structure of a base body. It is a figure which shows the structure of a slider support body. It is a figure which shows the detail of a slider support body. It is a figure which shows the structure of a slider and a shaft body. It is a figure which shows operation | movement of a 3-DOF active rotary joint. It is a figure which shows operation | movement of a 3-DOF active rotary joint. It is a figure which shows operation | movement of a 3-DOF active rotary joint.

(First embodiment)
Hereinafter, the three-degree-of-freedom active rotary joint according to the first embodiment will be described with reference to the accompanying drawings. FIG. 1 is a perspective view showing a three-degree-of-freedom active rotary joint according to this embodiment. FIG. 2 is an exploded perspective view of a part of the three-degree-of-freedom active rotary joint according to the present embodiment.
As shown in FIGS. 1 and 2, the three-degree-of-freedom active rotary joint is provided between the pair of links 10a and 10b.
The three-degree-of-freedom active rotary joint includes a rotary ball 20, rotary motors 100x, 100y, and 100z for X axis, Y axis, and Z axis, and rotary motors for X axis, Y axis, and Z axis. Movable bodies 110x, 110y, and 110z that respectively support 100x, 100y, and 100z, a rotating ball receiver 30 that supports the rotating sphere 20 to be rotatable in an arbitrary direction, and a base body 140 that supports the movable bodies 110x, 110y, and 110z. It is comprised including. In FIG. 2, the Y-axis and Z-axis rotary motors 100y and 100z and the movable bodies 110y and 110z have the same configuration as the X-axis rotary motor 100x and the movable body 110x, and are omitted. Yes.

  The X-axis, Y-axis, and Z-axis rotary motors 100x, 100y, and 100z are rotary actuators that are mutually connected so that the output shafts 101x, 101y, and 101z are respectively directed to the origin of three orthogonal axes. Are coupled to the rotating sphere 20 in a state of being orthogonally arranged. That is, when the rotary motor 100x for the X axis is driven, the corresponding output shaft 101x rotates the rotating sphere 20 around the X axis. When the rotary motor 100y for Y axis is driven, the corresponding output shaft 101y (not shown) rotates the rotating sphere 20 around the Y axis. When the rotary motor 100z for the Z axis is driven, the corresponding output shaft 101z rotates the rotating sphere 20 around the Z axis.

  These X-axis, Y-axis, and Z-axis rotary motors 100x, 100y, and 100z are integrated with, for example, a geared motor combined with a reduction gear and an encoder that measures the rotation angle and rotation speed. It is configured. The rotary motors 100x, 100y, and 100z of the present embodiment use small and lightweight rotary motors without using a hollow shaft or the like.

  The rotating sphere 20 is a rotating body and is arranged so that its center coincides with the origin of three orthogonal axes. One link 10a is connected to the rotating sphere 20 at an equal distance from each of the output shafts 101x, 101y, and 101z. More specifically, the link 10a is at an equal distance from each of the connecting portion between the rotating sphere 20 and the output shaft 101x, the connecting portion between the rotating sphere 20 and the output shaft 101y, and the connecting portion between the rotating sphere 20 and the output shaft 101z. It is connected.

As shown in FIG. 2, the rotating ball receiver 30 has a hollow spherical shape that is concentric with the rotating ball 20, and is a spherical slide that supports the rotating ball 20 so as to be rotatable in any direction. Acts as a bearing. Here, the configuration of the rotating ball receiver 30 will be described with reference to FIGS. 3, 4, and 5.
FIG. 3A is a perspective view of the rotating ball receiver 30 as viewed from above, and FIG. 3B is an exploded perspective view of the rotating ball receiver 30.
As shown in FIGS. 3A and 3B, the rotating ball receiver 30 is configured by combining a plurality (three) of receiving members 31. Each of the receiving members 31 has the same shape and is formed in a shape obtained by curving a substantially rhombus. Cylindrical shaft portions 32x, 32y, and 32z (not shown) are formed on the outer peripheral surface of each receiving member 31, respectively. The shaft portions 32x, 32y, and 32z are fitted to inner bearings 131 of slider supports 114x, 114y, and 114z, which will be described later, of the movable bodies 110x, 110y, and 110z. In a state where the rotating ball receiver 30 supports the rotating ball 20, the protruding directions of the shaft portions 32x, 32y, and 32z are directions along the Z axis, the X axis, and the Y axis, respectively. Each receiving member 31 is formed with a fastening hole 33 for fastening a bolt in order to connect adjacent receiving members 31 to each other.

  The rotating ball receiver 30 covers the lower hemisphere (lower half) of the rotating ball 20 so as to rotatably support the rotating ball 20, but at least a part of the upper hemisphere (upper half) of the rotating ball 20 is also supported. Covering. Here, as shown in FIG. 3 (a), it is cut in the vertical direction along the II line passing through the top 34 of one receiving member 31, and concretely referring to FIG. 4 seen from the arrow direction. Explained. As shown in FIG. 4, the top 34 of the receiving member 31 reaches an angle α (approximately 108.5 degrees) larger than 90 degrees from the vertically downward direction with the center 0 of the rotating sphere 20 as a reference. This sectional view is the same when the top 34 of the other receiving member 31 is cut. Therefore, when the rotating ball receiver 30 supports the rotating ball 20, the rotating ball receiver 30 covers a part of the upper hemisphere of the rotating ball 20 by the top 34 of each receiving member 31 and holds the rotating ball 20. Therefore, the rotating ball 20 can be supported without coming out of the rotating ball receiver 30. Further, since only a part of the upper hemisphere of the rotating sphere 20 is covered, there is no interference when the link 10a protruding from the rotating sphere 20 moves, and the movable range of the link 10a can be widened. it can. The rotating sphere 20 of the present embodiment is configured to be rotatable around any one axis within a range of, for example, ± 35 degrees.

In addition, the structure of the receiving member 31 is not restricted to what was mentioned above, For example, the receiving member 41 shown in FIG. 5 may be sufficient. FIG. 5A is a perspective view of the rotating ball receiver 40, and FIG. 5B is a perspective view of the receiving member 41.
The rotation receiver 40 is configured by combining a plurality (three) of receiving members 41 having the same shape. The receiving member 41 is formed with unevenness on the joint surface 42 of the receiving member 41 so that the receiving members 41 can be easily positioned when the adjacent receiving members 41 are joined together. That is, as shown in FIG. 5 (b), one receiving member 41 has two joint surfaces 42, a convex portion 43 is formed on one joint surface 42, and a concave portion 44 is formed on the other joint surface 42. Has been. The convex portion 43 has a shape that fits just into the concave portion 44.
Further, since the other adjacent receiving member 41 has the same shape as the receiving member 41 shown in FIG. 5B, the convex portion 43 of one adjacent receiving member 41 is fitted in the concave portion 44 of the receiving member 41. Then, the concave portion 44 of the other receiving member 41 adjacent to the convex portion 43 of the receiving member 41 is fitted. In other words, the rotating ball receiver 40 can be assembled so that no step is generated between the receiving members 41 by matching the unevenness of the adjacent receiving members 41. Therefore, the rotating ball receiver 40 can smoothly rotate the rotating ball 20 and improve the dynamic characteristics of the rotating ball 20.

The movable bodies 110x, 110y, and 110z support the rotary ball receiver 30 as well as the X-axis, Y-axis, and Z-axis rotary motors 100x, 100y, and 100z, respectively. Here, the movable body 110x will be described with reference to FIG. 2, FIG. 6, and FIG. The movable bodies 110y and 110z have the same configuration as the movable body 110x, and the description thereof is omitted.
As shown in FIG. 2, the movable body 110x includes a motor receiver 111x that supports the rotary motor 100x, a slider 113x that is formed integrally with the motor receiver 111x, and a slider support body 114x that supports the slider 113x in a slidable manner. It is comprised including.

The motor receiver 111x is formed with an insertion hole 112x through which the output shaft 101x of the X-axis rotary motor 100x is inserted. The motor receiver 111x supports the rotary motor 100x for the X axis so that the output shaft 101x is directed toward the center of the rotating sphere 20.
The slider 113x is concentric with the rotating sphere 20 and is formed in a prismatic shape curved around the Y axis. The slider 113x extends integrally from the lower part of the motor receiver 111x toward the slider support 114x.
The slider support 114x is formed in a hollow prismatic shape that is concentric with the rotating sphere 20 and curved around the Y axis, and can slide the slider 113x with low friction inside. Therefore, the slider 113x slides around the Y axis on the XZ plane with respect to the slider support 114x.

Here, the slider support 114x will be described with reference to FIGS. FIG. 6A is a perspective view of the slider support 114x, and FIG. 6B is an exploded perspective view of the slider support 114x. FIG. 7A is a perspective view showing a part of the slider support 114x, and FIG. 7B is a cross-sectional view of the slider support 114x. In each figure, the slider support body 114x shown in FIG. 2 is shown upside down.
The slider support 114x has a skeleton formed by two side portions 115x. As shown in FIGS. 6B and 7A, a plurality (four) of rotating shafts 116x are suspended in the horizontal direction between the side surface portions 115x. Each rotating shaft 116x pivotally supports two rollers 117x that are spaced apart from each other.
Each side surface portion 115x includes a plurality of rotation shafts 116x between the outer side (OUT side shown in FIG. 7A) and the inner side (IN side shown in FIG. 7A). (Two) rotating shafts 118x are suspended in a substantially vertical direction. Each rotation shaft 118x pivotally supports a roller 119x.

When viewed from the sliding direction of the slider 113x with the slider 113x assembled to the slider support 114x, the rollers 117x and 119x are in contact with the respective sides of the slider 113x as shown in FIG. 7B. That is, there is a gap substantially equal to the thickness t of the slider 113x between the roller 117x disposed on the outer side (arrow OUT direction side) and the roller 117x disposed on the inner side (arrow IN direction side). Is formed. Further, a gap substantially equal to the width w of the slider 113x is formed between the roller 119x disposed on the right side (arrow R direction side) and the roller 119x disposed on the left side (arrow L direction side). Is formed.
When the slider 113x slides in the slider support 114x, the rollers 117x and 119x roll on the side surfaces of the slider 113x, so that the slider 113x can slide with low friction without rattling.

  As shown in FIG. 6, the slider support 114 x is provided with an outer bearing holding portion 121 x that holds the outer bearing 130 and an inner bearing holding portion 123 x that holds the inner bearing 131. As shown in FIG. 6B, the outer bearing holding part 121x is divided into left and right parts, and holds the outer bearing 130 by sandwiching it from the left and right. Further, communication holes 122x and 120x through which fixing bolts (not shown) are inserted are formed in the outer bearing holding portion 121x and the side surface portion 115x, respectively. In a state where the outer bearing holding portion 121x is sandwiched between the left and right side surface portions 115x, it is inserted into the communication holes 120x and 122x and fixed from both sides using fixing bolts (not shown). Then, the outer bearing 130 is completely held by the outer bearing holding portion 121x. The inner bearing holding portion 123x has the same configuration, and the description thereof is omitted.

  In the state where the slider support body 114x is assembled, the axis lines of the outer bearing 130 and the inner bearing 131 are on the same line. In the outer bearing 130, a shaft portion 141x coaxial with a Z-axis described later of the base body 140 is fitted. Further, in the inner bearing 131, the shaft portion 32x coaxial with the Z-axis of the rotating ball receiver 30 is fitted.

  As shown in FIG. 2, the base body 140 has a hollow sphere shape that is concentric with the rotating sphere 20. The other link 10b is connected to the lower end of the base body 140 along the vertically downward direction. In addition, columnar shaft portions 141x, 141y, and 141z that are fitted to the outer bearings 130 of the slider supporters 114x, 114y, and 114z are provided on the upper edge portion of the base body 140 at regular intervals. Yes. In a state where the rotating ball receiver 30 supports the rotating ball 20, the protruding directions of the shaft portions 141x, 141y, and 141z are directions along the Z axis, the X axis, and the Y axis, respectively. That is, the shaft portions 141x, 141y, and 141z are arranged orthogonally to each other so as to be directed to the origin of three orthogonal axes. The shaft portions 141x, 141y, and 141z have the base body 140 bent to improve the rigidity in order to receive the load of the three-degree-of-freedom active rotary joint.

According to the movable body 110x configured as described above, the motor receiver 111x of the movable body 110x supports the rotary motor 100x for the X axis so that the output shaft 101x points to the origin of the rotating sphere 20.
Further, the slider support 114x of the movable body 110x supports the slider 113x so as to be slidable. Therefore, the X-axis rotary motor 100x and the rotating ball 20 indirectly coupled to the slider 113x are allowed to rotate around the bending direction of the slider 113x, that is, the Y-axis.
Further, according to the movable body 110x configured as described above, the slider support body 114x of the movable body 110x is located between the shaft portion 32x of the rotating ball receiver 30 and the shaft portion 141x of the base body 140. And the outer bearing 130 are supported so as to be rotatable around the Z axis. Accordingly, the X-axis rotary motor 100x and the rotating sphere 20 are allowed to rotate around the Z-axis.

Here, the operation of the movable body 110x will be specifically described with reference to FIGS. 8 to 10 are views of a three-degree-of-freedom active rotary joint as viewed from the Y-axis direction.
First, from the state shown in FIG. 8, when the Y-axis rotary motor 100y is driven to rotate the rotating ball 20 in the direction of the arrow A, the Y-axis rotary motor 100x and the Z-axis rotary motor 100z. Similarly (not shown) also rotates in the direction of arrow A. Since the slider support body 114x of the movable body 110x supports the slider 113x so as to be slidable, the motor receiver 111x and the slider 113x of the movable body 110x are synchronized with the rotation of the rotary motor 100x for the X axis. With respect to the support body 114x, it rotates in the arrow A 'direction around the Y axis, and the state shown in FIG.
Here, as shown in FIG. 9, the link 10a coupled to the rotating sphere 20 similarly rotates around the Y axis, so that rotational relative motion is possible between the two links.

Next, when the Y-axis rotary motor 100y is driven to rotate the rotating ball 20 in the arrow B direction from the state shown in FIG. 9, the Y-axis rotary motor 100x and the Z-axis rotary motor are rotated. Similarly, 100z (not shown) rotates in the direction of arrow B. In synchronization with the rotation of the rotary motor 100x for the X axis around the Y axis, the motor receiver 111x and the slider 113x of the movable body 110x rotate in the direction of the arrow B ′ around the Y axis with respect to the slider support 114x. The state shown in FIG. 10 is obtained.
Here, as shown in FIG. 10, the link 10a coupled to the rotating sphere 20 similarly rotates around the Y axis, so that rotational relative motion is possible between the two links.

  Next, when the Z-axis rotary motor 100z is driven from the state shown in FIG. 8 to rotate the rotating sphere 20 in any one direction around the Z-axis, the rotating sphere 20 rotates around the Z-axis. Accordingly, the X-axis rotary motor 100x and the Y-axis rotary motor 100y rotate in the same direction. The slider support 114x of the movable body 110x is allowed to rotate around the Z axis with respect to the shaft portion 32x of the rotating ball receiver 30 and the shaft portion 141x of the base body 140 via the inner bearing 131 and the outer bearing 130. Yes. Therefore, the movable body 110x rotates around the Z axis in synchronization with the rotation of the rotary motor 100x around the Z axis. Accordingly, the link 10a connected to the rotating sphere 20 similarly rotates around the Z axis, so that rotational relative motion is possible between the two links.

In addition, the movable bodies 110y and 110z are configured similarly to the movable body 110x. Therefore, the movable body 110y allows rotation of the Y-axis rotary motor 100y and the rotating sphere 20 around the X axis and around the Z axis. The movable body 110z allows the rotation of the Z-axis rotary motor 100z and the rotating sphere 20 around the Y axis and the X axis.
Therefore, when the rotary motors 100x, 100y, and 100z for the X axis, the Y axis, and the Z axis are driven, the rotating sphere 20 rotates about the X axis, the Y axis, and the Z axis, respectively. One link 10a connected to 20 can perform any rotational relative motion with respect to the other link 10b.

  In particular, in the three-degree-of-freedom active rotary joint of the present embodiment, one link 10a is relative to the rotating sphere 20 for each output shaft of the rotary motors 100x, 100y, and 100z for the X axis, the Y axis, and the Z axis. 101x, 101y, and 101z are connected at substantially equal distances. That is, since the X-axis, Y-axis, and Z-axis rotary motors 100x, 100y, and 100z are arranged in a balanced manner with respect to one link 10a, the weight balance of the three-degree-of-freedom active rotary joint is balanced. It is stable and the dynamic characteristics of the link can be improved. Also, since the output shaft of the rotary motor does not have to use a special hollow shaft, a small and lightweight rotary motor can be used, and the three-degree-of-freedom active rotary joint can be configured to be small and lightweight. Dynamic characteristics can be improved.

(Second Embodiment)
Hereinafter, the three-degree-of-freedom active rotary joint according to the second embodiment will be described with reference to the accompanying drawings. FIG. 11 is a perspective view showing a three-degree-of-freedom active rotary joint according to this embodiment. The three-degree-of-freedom active rotary joint of this embodiment is different from the first embodiment in that the arrangement of rotary motors for the X-axis, Y-axis, and Z-axis is changed, and is different from the first embodiment. The explanation will focus on the points.

As shown in FIG. 11, the three-degree-of-freedom active rotary joint is provided between the pair of links 10a and 10b.
The three-degree-of-freedom active rotary joint includes a rotary ball 20, rotary motors 200x, 200y, and 200z for the X, Y, and Z axes, and rotary motors for the X, Y, and Z axes. Movable bodies 210x, 210y, 210z that rotate the rotating sphere 20 by driving each of 200x, 200y, 200z, a rotating sphere receiver 30 that supports the rotating sphere 20 so as to be rotatable in any direction, and for the X axis and the Y axis And a base body 240 that supports the rotary motors 200x, 200y, and 200z for the Z-axis. The same rotary motors as those in the first embodiment are used for the X-axis, Y-axis, and Z-axis rotary motors 200x, 200y, and 200z. Note that the same components as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

The X-axis, Y-axis, and Z-axis rotary motors 200x, 200y, and 200z of the present embodiment are base bodies in a state in which the output axes are arranged orthogonally to each other so that the output axes are directed to the origin of three orthogonal axes. 240.
As shown in FIG. 12, the base body 240 has a hollow sphere shape that is concentric with the rotating sphere 20. The other link 10b is connected to the lower end of the base body 240 along the vertically downward direction. In addition, motor receivers 241x, 241y, and 241z that support rotary motors 200x, 200y, and 200z for the X axis, the Y axis, and the Z axis are provided on the upper edge of the base body 240 at regular intervals. It has been. In each motor receiver 241x, 241y, 241z, output shafts 201x, 201y, 201z of the rotary motors 200x, 200y, 200z for the X axis, the Y axis, and the Z axis (see the two-dot chain line shown in FIG. 12) Insertion holes 242x, 242y, and 242z are formed. The motor receivers 241x, 241y, and 241z are provided with rotary motors 200x, 200y, and 200z for the X axis, the Y axis, and the Z axis so that the output shafts 201x, 201y, and 201z are oriented toward the center of the rotating sphere 20. To support. Each motor receiver 241x, 241y, 241z has a base body 240 that is curved to improve the rigidity in order to receive the load of the three-degree-of-freedom active rotary joint.

  The movable bodies 210x, 210y, and 210z are coupled to output shafts 201x, 201y, and 201z of rotary motors 200x, 200y, and 200z for the X axis, the Y axis, and the Z axis, respectively. Accordingly, when the X-axis rotary motor 200x is driven, the corresponding movable body 210x rotates around the X-axis. When the rotary motor 200y for Y axis is driven, the corresponding movable body 210y rotates around the Y axis. When the Z-axis rotary motor 200z is driven, the corresponding movable body 210z rotates around the Z axis.

  Here, the movable body 210x will be described with reference to FIGS. 11 and 13 to 15. Note that the movable bodies 210y and 210z have the same configuration as the movable body 210x, and a description thereof will be omitted. As shown in FIG. 11, the movable body 210x includes a slider support 211x that rotates in synchronization with the output shaft 201x of the rotary motor 200x for the X axis, a slider 220x that slides within the slider support 211x, and a slider 220x. And a shaft body 230x that connects the rotary sphere 20 to each other.

The slider support 211x is formed in a hollow prismatic shape concentric with the rotating sphere 20 and curved around the Z axis, and can slide the slider 200x with low friction inside.
Here, the slider support 211x will be described with reference to FIGS. FIG. 13A is a view of the slider support 211x viewed from the center of the rotating sphere 20 in the X-axis direction. 13B is a view of FIG. 13A viewed from the direction of arrow C, and FIG. 13C is a view of FIG. 13B viewed from the direction of arrow D. FIG. 13D is a cross-sectional perspective view taken along the line II-II in FIG.

  The slider support 211x has a skeleton formed by two side portions 212x. Similarly to the first embodiment, the slider support 211x is arranged such that a plurality of rollers can roll on each side of the slider 220x so that the slider 220x can slide with low friction without causing rattling. Has been.

  A bearing 250 is held by a bearing holding portion 213x inside the slider support 211x (in the direction of the arrow IN shown in FIG. 13). The shaft portion 32x of the rotating ball receiver 30 described in the first embodiment is fitted to the bearing 250. Further, on the outside of the slider support 211x (in the direction of the arrow OUT shown in FIG. 13), a rotary receiver 214x that receives the rotation of the output shaft 201x of the rotary motor 200x for X-axis is provided.

Here, with reference to FIG. 14, the rotation receiving body 214x will be described. FIG. 14A is a perspective view showing a state before the rotary receiver 214x and the X-axis rotary motor 200x are coupled, and FIG. 14B is an exploded perspective view of the rotary receiver 214x. .
The rotary receiver 214x includes a motor connecting member 215x and a support connecting member 216x. The motor connecting member 215x rotates in synchronization with the output shaft 201x by being fixed to the X-axis rotary motor 200x by using a plurality of fixing bolts (not shown) along the axial direction of the output shaft 201x. To do. As shown in FIG. 14B, the support connecting member 216x is fitted with the non-rotating protrusion 217x of the motor connecting member 215x, and then a plurality of fixing bolts not shown in the direction orthogonal to the axial direction of the output shaft 201x. By fixing with, it is combined with the motor connecting member 215x.
The support connecting member 216x is fixed from both sides using fixing bolts while being sandwiched between the left and right side surface portions 212x. Therefore, the slider support 211x rotates around the X axis in synchronization with the output shaft 201x.

The slider 220x is concentric with the rotating sphere 20 and is formed in a prismatic shape curved around the Z axis. The tip of the slider 220x supports the shaft body 230x so as to be directed toward the center of the rotating sphere 20.
Here, the slider 220x and the shaft body 230x will be described with reference to FIG. A plurality (two) of bearings 250 are held at the tip of the slider 220x so as to be spaced apart so that the axial direction is along the Y-axis direction. Therefore, the shaft body 230 x can be rotated around the Y axis by the bearing 250. Further, the shaft body 230x is coupled to the rotating sphere 20 on the opposite side supported by the slider 220x.

  As shown in FIG. 15, in addition to the shaft body 230x, the shaft body 230y of the movable body 210y and the shaft body 230z of the movable body 210z are coupled to the rotating sphere 20. The shaft bodies 230x, 230y, and 230z are arranged orthogonally to each other so as to be directed to the origin of three orthogonal axes. Further, one link 10a is connected to the rotating sphere 20 at an equal distance from each of the shaft bodies 230x, 230y, and 230z. More specifically, the link 10a is at an equal distance from each of the coupling portion between the rotating sphere 20 and the shaft body 230x, the coupling portion between the rotating sphere 20 and the shaft body 230y, and the coupling portion between the rotation sphere 20 and the shaft body 230z. It is connected.

According to the movable body 210x configured as described above, when the rotary motor 200x for the X axis is driven, the rotating sphere 20 is rotated around the X axis via the slider support body 211x, the slider 220x, and the shaft body 230x. Let Further, the slider support 211x of the movable body 210x supports the slider 220x so as to be slidable. Therefore, the shaft body 230x and the rotating sphere 20 indirectly coupled to the slider 220x are allowed to rotate around the bending direction of the slider 220x, that is, the Z axis.
Further, according to the movable body 210x configured as described above, the slider 220x of the movable body 210x supports the shaft body 230x so as to rotate around the Y axis. Therefore, the shaft body 230x and the rotating sphere 20 are allowed to rotate around the Y axis.

Here, the operation of the movable body 210x will be specifically described with reference to FIGS. 16 to 18 are diagrams of a three-degree-of-freedom active rotary joint viewed from the Z-axis direction.
First, from the state shown in FIG. 16, when the shaft body 230z rotates the rotating sphere 20 in the arrow E direction by driving the Z-axis rotary motor 200z, the shaft body 230x and the slider 220x also rotate. Since the slider support body 211x of the movable body 210x supports the slider 220x so as to be slidable, the shaft body 230x and the slider 220x rotate in the direction of the arrow E ′ around the Z axis with respect to the slider support body 211x. The state shown in FIG.
Here, as shown in FIG. 17, since the link 10a connected to the rotating sphere 20 also rotates around the Z axis, rotational relative motion is possible between the two links.

Next, from the state shown in FIG. 17, when the shaft body 230z rotates the rotating sphere 20 in the direction of arrow F by driving the Z-axis rotary motor 200z, the shaft body 230x and the slider 220x also rotate. The shaft body 230x and the slider 220x rotate in the direction of the arrow F ′ around the Z axis with respect to the slider support body 211x, and are in the state shown in FIG.
Here, as shown in FIG. 18, the link 10a connected to the rotating sphere 20 similarly rotates around the Z axis, so that rotational relative motion is possible between the two links.

  Next, from the state shown in FIG. 16, when the shaft body 230y rotates the rotating sphere 20 in either direction around the Y axis by driving the rotary motor 200y for the Y axis, Along with the rotation, the shaft body 230x of the movable body 110x also rotates in the same direction. The shaft body 230x is allowed to rotate around the Y axis via the bearing 250 of the slider 220x. Accordingly, the shaft body 230x rotates about the Y axis in synchronization with the rotation about the Y axis of the rotary motor 200y for the Y axis. Accordingly, the link 10a connected to the rotating sphere 20 similarly rotates around the Y axis, so that rotational relative motion is possible between the two links.

The movable bodies 210y and 210z are configured in the same manner as the movable body 210x. Therefore, the movable body 210y allows the shaft body 230y and the rotating sphere 20 to rotate around the X axis and around the Z axis. The movable body 210z allows the shaft body 230z and the rotating sphere 20 to rotate around the Y axis and around the X axis.
Therefore, when the rotary motors 200x, 200y, and 200z for the X axis, the Y axis, and the Z axis are driven, the rotating sphere 20 rotates about the X axis, the Y axis, and the Z axis, respectively. One link 10a connected to 20 can perform any rotational relative motion with respect to the other link 10b.

In particular, in the three-degree-of-freedom active rotary joint of the present embodiment, one link 10a is coupled to the rotary ball 20 to the X-axis, Y-axis, and Z-axis rotary motors 200x, 200y, and 200z. The movable bodies 210x, 210y, and 210z are connected at substantially equal distances from the shaft bodies 230x, 230y, and 230z. That is, since the shaft bodies 230x, 230y, and 230z are arranged in a balanced manner with respect to one link 10a, the weight balance of the three-degree-of-freedom active rotary joint is stabilized, and the dynamic characteristics of the link can be improved. .
The X-axis, Y-axis, and Z-axis rotary motors 200x, 200y, and 200z are not coupled to the rotating sphere 20 and are supported in a balanced manner on the base body 240. Therefore, the rotating sphere 20 can be reduced in weight and the center of gravity is located below the three-degree-of-freedom active rotary joint, so that the dynamic characteristics of the link can be improved.
Also, since the output shaft of the rotary motor need not use a special hollow shaft, a small and lightweight rotary motor can be used, and the three-degree-of-freedom active rotary joint can be configured to be small and lightweight. The dynamic characteristics of the link 10a can be improved.

  As mentioned above, although this invention was demonstrated with various embodiment, this invention is not limited only to these embodiment, A change etc. are possible within the scope of the present invention. In the present invention, the rotating sphere 20 is used as the rotating body and is rotatably supported by the rotating ball receiver 30. However, since the rotating sphere 20 is supported by the output shaft or the shaft body, the kinematic principle is used. It is not necessary to make the rotating body other than a spherical shape (for example, a hexahedron), or to support the rotating body rotatably with the rotating ball receiver 30. However, using the rotating sphere 20 and supporting it with the rotating sphere receiver 30 provides high rigidity, and can reduce the influence of the assembly error and dimensional error of each part and perform precise movement.

  10a: Link 10b: Link 20: Rotating sphere (rotating body) 30, 40: Rotating sphere receiver (rotating body receiver) 31, 41: Receiving member 42: Joint surface 43: Convex part 44: Concave part 100x, 100y, 100z: Rotation Type motor (rotary actuator) 101x, 101y, 101z: output shaft 110x, 110y, 110z: movable body 113x, 113y, 113z: slider 114x, 114y, 114z: slider support 200x, 200y, 200z: rotary type motor (rotary actuator) 201x, 201y, 201z: Output shaft 210x, 210y, 210z: Movable body 211x, 211y, 211z: Slider support body 220x, 220y, 220z: Slider 230x, 230y, 230z: Shaft body

Claims (5)

A 3-DOF active rotary joint provided between a pair of links,
A rotating body to which one of the pair of links is connected;
Each output shaft is arranged so as to be directed to the center of the rotating body and orthogonal to each other, and an X-axis, Y-axis, Z-axis rotary actuator for rotating the rotating body,
A movable body that supports the output shaft of the rotary actuator for the X axis at a position where the output shaft is coupled to the rotary body and allows the rotation of the rotary body about the Y axis and the Z axis;
A movable body that supports the output shaft of the rotary actuator for the Y axis at a position where the output shaft is coupled to the rotary body and allows the rotation of the rotary body about the X axis and the Z axis;
A movable body that supports the output shaft of the rotary actuator for the Z axis at a position where the output shaft is coupled to the rotary body and allows the rotation of the rotary body about the X axis and the Y axis;
The three-degree-of-freedom active rotary joint, wherein the one link is connected to the rotary body at a position substantially the same distance from each output shaft. A 3-DOF active rotary joint provided between a pair of links,
A rotating body to which one of the pair of links is connected;
Each output shaft is arranged so as to be directed to the center of the rotating body and orthogonal to each other, and an X-axis, Y-axis, Z-axis rotary actuator for rotating the rotating body,
A movable body coupled to an output shaft of the rotary actuator for the X axis, rotating the rotary body around the X axis via the shaft body, and allowing rotation of the rotary body around the Y axis and the Z axis;
A movable body that is coupled to an output shaft of the rotary actuator for the Y axis, rotates the rotary body around the Y axis via the shaft body, and allows the rotary body to rotate around the X axis and the Z axis;
A movable body coupled to the output shaft of the rotary actuator for the Z axis and rotating the rotary body around the Z axis via the shaft body and allowing the rotary body to rotate around the X axis and the Y axis; Prepared,
The three-degree-of-freedom active rotary joint, wherein the one link is connected to the rotary body at a position substantially the same distance from the shafts. A rotating body receiver that rotatably supports the rotating body;
The rotating body receiver is formed by combining a plurality of receiving members,
The three-degree-of-freedom active rotary joint according to claim 1, wherein the receiving member covers at least a part of an upper half of the rotary body. A rotating body receiver that rotatably supports the rotating body;
The rotating body receiver is formed by combining a plurality of receiving members,
3. The three-degree-of-freedom active according to claim 1, wherein the plurality of receiving members are formed with irregularities on joint surfaces where they are in contact with each other, and each of the plurality of receiving members is formed in the same shape. Rotating joint. The movable body includes a slider that is concentrically curved with the rotating body, and a slider support body that slidably supports the slider,
5. The three-degree-of-freedom active according to claim 1, wherein the slider slides on the slider support to allow rotation about any one axis of the rotating body. 6. Rotating joint.

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