JP2564416Y2 - Arm structure of parallel robot - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a parallel robot having actuators arranged in parallel.

[0002]

2. Description of the Related Art Conventionally, a parallel robot having six degrees of freedom in which actuators are arranged in parallel is disclosed in Transactions of the Japan Society of Mechanical Engineers (C), Vol.
There are techniques such as those described in In a parallel robot equipped with this technology, six arms are each formed of three links, and these three links are connected to each other by three pairs of turns that rotate about one axis. The tip of this arm is connected to the bracket by a ball pair, and the position and posture of the bracket are controlled by disposing a drive motor at each of the tips of the arms.

[0003]

In such a conventional parallel robot, when a ball joint is used in a pair of balls connecting the tip of an arm to a bracket, there are the following problems in increasing the operating range of the parallel robot. That is, as shown in FIG.
It comprises a first joint 86 having a sphere 86a and a second joint 87 having a socket 87a for holding the sphere 86a. The first joint 86 can swing in any direction with respect to the second joint 87. It has become. This ball joint 85
In order to increase the swing angle θ of the first joint portion 86, the diameter of the shaft portion supporting the sphere 86a of the first joint portion 86 must be reduced, or the thickness X of the socket 87a covering the sphere 86a must be reduced. . In these two cases,
If the diameter of the shaft portion supporting the sphere 86a is reduced, the rigidity of the entire parallel robot is significantly reduced, which is not preferable. In addition, it is extremely difficult to perform such processing using a standard ball joint for cost reduction. is there. When the thickness X of the socket 87a covering the sphere 86a is reduced, it is relatively easy to perform such processing on the standard ball joint. However, when the arm of the parallel robot swings, the sphere is formed. 86a is a socket 87a
There was a problem that it was easy to come off.

The present invention has been made in order to solve the above-mentioned problems. The thickness of the ball 86a covering the sphere 86a by the socket 87a is reduced, and the sphere 86a is formed even when the swing angle of the ball joint 85 is increased. An object of the present invention is to provide an arm structure of a parallel robot that does not come off the socket 87a and has a large movable range of the arm.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to achieve the above-mentioned object, and has six arms consisting of a link and a rod connected by a first pair of balls, and a base on a base. Three support portions arranged at equal intervals to each other to support two ends of the six arms, two brackets having tips of the six arms mounted on the same plane by a second pair of balls, and In a parallel robot having six motors for swinging the arms separately, at least the second ball pair of the first ball pair and the second ball pair is a first joint part having a ball and the ball. A ball joint comprising a second joint having a socket to be held, and a half surface of one side of the sphere is rotatably held in a state exposed from the socket, and is supported by the support. Arm is characterized in that it is biased in a direction to press said spherical body to said socket side by an elastic member.

[0006]

The parallel robot constructed as described above is
Each arm is independently swung by a motor, and the bracket at the tip of the arm can be controlled. At this time, since the one half surface of the sphere of the ball joint is exposed from the socket, the swing angle of the arm can be increased. Further, since the two arms are urged by the elastic member in a direction of pressing the sphere toward the socket, the sphere of the ball joint can be prevented from falling off the socket.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described with reference to the drawings. As shown in FIGS. 1 to 4, the parallel robot according to the present embodiment mainly includes a base 1 fixed to the outside,
, A bracket 2 for attaching an end effector such as a hand, and six arms 31 connecting these two members.

The base 1 is a hexagonal member, and the parallel robot of the present embodiment has a hexagonal box shape by the base 1 and the protective cover 80. That is, a side surface protection cover 80a is attached to the outer periphery of the base 1, and a bottom surface protection cover 80b is attached to the side surface protection cover 80a in parallel with the base 1 plane.
The base 1, the side protection cover 80a and the bottom protection cover 80b are attached by bolts (not shown), and the base 1 and the protection cover 80 can be easily removed. In addition, three notches 80c are provided on the side surface protection cover 80a and the bottom surface protection cover 80b so that the six arms 31 can swing. Further, stoppers 83 and 84 indicating the swing end of the arm 31 are attached to two places of the notch portion 80c on the bottom surface protection cover 80b side and the side surface protection cover 80a side.

In the box-shaped interior formed by the base 1 and the protective cover 80, three support portions 11 are formed at equal intervals, and each of these support portions 11 is provided with six arms 31 having this number. Two are supported in order. Therefore,
The six arms 31 are supported by the support portions 11 respectively.
Since the three sets have the same structure, the following two sets are attached to the support 11.
Only the arm 31 will be described.

The supporting portion 11 includes two side plates 81 for supporting the motors 41 for individually rotating the arms 31.
And a back plate 82 connecting the two side plates 81. The two side plates 81 are installed in parallel with each other,
The side plate 81 and the back plate 82 are fixed vertically to the base 1. Therefore, the parallel robot of the present embodiment has a hexagonal box shape formed by the base 1 and the protective cover 80 described above, and a U-shaped box shape formed by the side plate 81 and the back plate 82 forming the support portion 11. It has a double box shape depending on the shape.

The arms 31 each include a link 71 and a rod 72. One end of each of the two links 71 is connected to the motor 41.
Are supported so as to be rotatable coaxially about a rotation shaft 100. The motor 41 is connected to the side plate 81 of the protective cover 80.
The structure is such that the cylindrical portion 41b is driven to rotate with respect to the fixed portion 41a which is attached to the, and a link 71 is attached to the cylindrical portion 41b.

The cylindrical portion 4 has a direction opposite to the direction from the attachment portion of the link 71 to the cylindrical portion 41b toward the tip of the link 71.
A crescent-shaped balancer weight 41c is attached to the side surface of 1b, that is, the upper surface side of the cylindrical portion 41b when the link 71 is in the vertical direction as shown in FIG.
The back plate 82 of the support portion 11 is provided with the cylindrical portion 4.
A hole 82a is formed so as not to interfere when 1b rotates.

The link 71 and the rod 72 are connected by a ball joint 61 (first ball pair), respectively.
With these ball joints 61 as fulcrums, rods 72
Can swing three-dimensionally with respect to the link 71. The tip of the rod 72 is connected to the ball joint 5
1 is connected to the bracket 2. With this configuration, the link 71 can swing in the three-dimensional direction with the ball joint 51 (second ball pair) as a fulcrum with respect to the bracket 2.

As shown in detail in FIG. 5, the ball joint 51 has a first joint portion 91 comprising a sphere 91a and a bolt portion 91b, and a second joint having a socket 90a for holding the sphere 91a and a mounting portion 90b. And a section 90. The bolt portion 91b of the first joint portion 91 and the attachment portion 90b of the second joint portion 90 are attached to the bracket 2 and the rod 72, respectively. The socket 90a covers and holds a portion on the bolt portion 91b side from the center of the sphere 91a with a thickness of Y. The thickness Y is desirably 0 to widen the movable range, but is set to a value of about 0.5 to 1 mm in consideration of a processing error. That is, when the portion where the socket 90a covers the sphere 91a extends to the side of the bolt portion 91b, the sphere 91a is less likely to fall out of the socket 90a. The thickness Y can take various values near zero. The ball joint 61 is also subjected to the same processing.

The ends of a pair of arms supported by the support portion 11, that is, the second joint portions 90 of the ball joint 51 are connected by a spring 93 (elastic member). With the above configuration, the parallel robot of this embodiment is
By giving an operation command value from a control device (not shown) to each of the six motors 41 arranged above, each link 71
Is swung around the rotation axis 100, and the six links 71
The bracket 2 can be positioned by combining the swinging motions.

At this time, since the ball joints 51 and 61 at both ends of the rod 72 set the range in which the socket 90a covers the sphere 91a near 0 from the center of the sphere 91a to the bolt portion 91b, the arm 31 is movable. The range can be increased. Further, since the tips of a pair of arms supported by the support portion 11 are connected by a spring 93, even if the arm 31 swings greatly, the sphere 91a falls out of the socket 90a of the ball joints 51 and 61. Can be prevented.

In the embodiment described above, the spring 93 is attached to the arm 31. However, the spring 93a may be attached to the end of the rod 72 as shown by a broken line in FIG.

[0018]

As described above, in the parallel robot of the present invention, the two arms supported by the support portion are connected by the elastic member which urges the two arms in a direction approaching each other, and the first and second pairs of balls are connected. At least a second ball pair of the pair has a first joint having a ball and a second joint having a socket for holding the ball.
Since the ball joint is formed of a joint and one half surface of the sphere is rotatably held while being exposed from the socket, the swing angle of the arm can be increased. Also, since the two arms are urged by the elastic member in the direction of pressing the sphere toward the socket,
The sphere of the ball joint can be prevented from falling out of the socket.

[Brief description of the drawings]

FIG. 1 is a perspective view of a parallel robot according to an embodiment.

FIG. 2 is a cross-sectional view of the parallel robot of the present embodiment.

FIG. 3 is a view A of FIG. 2 of the parallel robot of the present embodiment;
It is an arrow view.

FIG. 4 is a view B of FIG. 2 of the parallel robot of the present embodiment;
It is an arrow view.

FIG. 5 is an enlarged view of the tip of the arm according to the present embodiment.

FIG. 6 is a diagram for explaining a conventional technique.

[Explanation of symbols]

 Reference Signs List 1 base 2 bracket 11 support part 31 arm 41 motor 51, 61 ball joint 71 link 72 rod 91 first joint part 91a sphere 90 second joint part 90a socket 93 spring

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor François Pierrot, France, 34070 Montpellier Ar 1 En 5 Rue Ampère 261 (72) Inventor Osamu Toyama 1-1-1 Asahimachi, Kariya-shi, Aichi Prefecture Inside Toyota Koki Co., Ltd. 56) References Japanese Translation of PCT International Publication No. 63-501860 (JP, A) JP-A-4-19082 (JP, A)

Claims (1)

(57) [Scope of request for utility model registration] 1. Six arms composed of a link and a rod connected by a first pair of balls, and three supports arranged at equal intervals on a base and supporting two ends of the six arms by two. Part, a bracket having tips of the six arms mounted on the same plane by a second ball pair, and six motors for swinging the six arms separately. At least the second ball pair of the one ball pair and the second ball pair is a ball joint including a first joint portion having a sphere and a second joint portion having a socket for holding the sphere,
One half surface of the sphere is rotatably held in a state exposed from the socket, and two arms supported by the support are urged by an elastic member in a direction of pressing the sphere toward the socket. A parallel robot characterized by the following.