JPH08403U - Parallel robot arm structure - Google Patents

Abstract

(57) [Abstract] [Purpose] An object of the present invention is to provide a parallel robot arm structure in which a sphere does not come off from a socket even when the swing angle of a ball joint is large, and the movable range of the arm is large. [Structure] Since one half surface of the sphere 91a of the ball joint 51 is rotatably held while being exposed from the socket 90a, the swing angle of the arm 31 can be increased. In addition, the two arms 31 are attached to the spring 93.
Therefore, even if the arm 31 swings, the sphere 91a of the ball joint 51 can be prevented from falling out of the socket 90a.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a parallel robot in which actuators are arranged in parallel.

[0002]

[Prior art]

 Conventionally, as a 6-DOF parallel robot in which actuators are arranged in parallel, there is a technique as described in Proceedings of the Japan Society of Mechanical Engineers (C edition), Vol. 56, No. 523 (1990-3) (P829). In a parallel robot equipped with this technology, six arms are each configured by three links, and these three links are connected to each other by three rotating pairs that rotate about one axis. The tip of this arm is connected to the bracket by a ball pair, and the position and attitude of the bracket are controlled by disposing a drive motor at each of the tips of this arm.

[0003]

[Problems to be solved by the device]

 When a ball joint is used for a ball pair that connects the arm tip to a bracket in such a conventional parallel robot, there are the following problems to widen the operation range of the parallel robot. That is, as shown in FIG. 6, the ball joint 85 includes a first joint part 86 having a sphere 86a and a second joint part 87 having a socket 87a for holding the sphere 86a. As a result, the first joint portion 86 can swing in any direction. In order to increase the swing angle θ of the ball joint 85, the diameter of the shaft portion of the first joint portion 86 that supports the spherical body 86a is reduced, or the thickness X of the socket 87a that covers the spherical body 86a is reduced. I have to do it. In such two cases, if the diameter of the shaft portion that supports the sphere 86a is reduced, the rigidity of the entire parallel robot is significantly reduced, which is not preferable, and a standard ball joint is used to reduce the cost. It is very difficult to perform such processing. Further, in the case where the socket 87a reduces the wall thickness X covering the sphere 86a, it is relatively easy to perform such processing on the standard ball joint, but when the arm of the parallel robot swings. In addition, there is a problem that the sphere 86a is easily separated from the socket 87a.

The present invention has been made in order to solve the above-mentioned problems. Even if the swing angle of the ball joint 85 is increased by reducing the wall thickness X of the socket 87a that covers the ball 86a, the ball 86a can be made larger. It is an object of the present invention to provide a parallel robot arm structure in which the arm does not come off from the socket 87a and the movable range of the arm is large.

[0005]

[Means for Solving the Problems]

 The present invention has been made in order to achieve the above-mentioned object, and includes six arms, which are links and rods connected by a first ball pair, and are equidistantly arranged on a base. Three support parts that support two ends of each of the six arms, a bracket in which the tips of the six arms are mounted on the same plane by the second ball pair, and the six arms are separately provided. In a parallel robot having six motors for swinging to at least one of the first ball pair and the second ball pair, at least the second ball pair has a first joint portion having a ball and a socket for holding the ball. The second joint part has a ball joint, and one half surface of the sphere is rotatably held in a state of being exposed from the socket, and the two arms supported by the support part are elastic members. And is characterized in that it is biased in a direction to press said spherical body to the socket-side I.

[0006]

[Action]

 In the parallel robot configured as described above, each arm can be independently swung by the motor to control the bracket at the tip of the arm. At this time, since the half surface on one side 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 biased 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.

[0007]

【Example】

 An embodiment of the present invention will be described with reference to the drawings. As shown in FIGS. 1 to 4, the parallel robot of the present embodiment mainly includes a base 1 fixed to the outside, a protective cover 80 installed around the base 1, and an end effector such as a hand. A bracket 2 for attaching the two and six arms 31 connecting the two members.

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

Inside the box shape formed by the base 1 and the protective cover 80, three support parts 11 are formed at equal intervals, and each of these support parts 11 has six arms 31 with this number. Two are supported in order. Therefore, the six arms 31 can be divided into three groups that are respectively supported by the support section 11, and since these three groups have the same configuration, the two arms attached to the support section 11 will be described below. Only the arm 31 of FIG.

The support portion 11 is composed of two side plates 81 that support the motors 41 that individually rotate and drive the arms 31, and a back plate 82 that connects the two side plates 81. The two side plates 81 are installed parallel to each other, and 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 ends of the two links 71 are supported by the motor 41 so as to be coaxially rotatable about the rotation shaft 100. The motor 41 has a structure in which the tubular portion 41b is rotationally driven with respect to the fixed portion 41a attached to the side plate 81 of the protective cover 80, and the link 71 is attached to the tubular portion 41b.

Further, when the link 71 is in the vertical direction as shown in FIG. 2, that is, the side surface of the cylinder portion 41b opposite to the direction from the attachment portion of the link 71 to the cylinder portion 41b toward the tip of the link 71. A crescent-shaped balancer weight 41c is attached to the upper surface side of the cylindrical portion 41b. A hole 82a is formed in the back plate 82 of the support portion 11 so as not to interfere with the rotation of the cylindrical portion 41b.

The link 71 and the rod 72 are connected by a ball joint 61 (first ball pair), and the rod 72 can swing in three dimensions with respect to the link 71 with the ball joint 61 as a fulcrum. ing. The tips of the rods 72 are connected to the bracket 2 via ball joints 51, respectively. With this configuration, the link 71 can swing in three-dimensional directions 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 includes a first joint portion 91 including a sphere 91a and a bolt portion 91b, and a second joint including a socket 90a for holding the sphere 91a and a mounting portion 90b. And a joint portion 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 of the sphere 91a on the bolt portion 91b side from the center thereof with a Y thickness. The wall thickness Y is preferably 0 in order 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, it is because it is more difficult for the ball 91a to come out of the socket 90a when the portion where the socket 90a covers the ball 91a extends to the side of the bolt portion 91b, and depending on the strength of the spring 93 and the movable range of the arm 31, which will be described later. , The wall thickness Y can take various values near 0. The ball joint 61 is also processed in the same manner.

The tips 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 configuration described above, the parallel robot of the present embodiment causes each link 71 to rotate about the rotation axis 100 by giving an operation command value from each of the six motors 41 arranged on the base 1 by a controller (not shown). It is possible to position the bracket 2 by swinging the bracket 2 and combining the swings of the six links 71.

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 to be near 0 on the bolt portion 91b side from the center of the sphere 91a, the arm 31 is movable. The range can be increased. Further, since the tips of the pair of arms supported by the support portion 11 are connected by the spring 93, the sphere 91a will fall out of the socket 90a of the ball joint 51, 61 even if the arm 31 swings largely. Can be prevented.

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

[0018]

[Effect of device]

 As described above, in the parallel robot of the present invention, the two arms supported by the supporting portion are connected by the elastic member that urges them toward each other, and the first ball pair and the second ball pair are connected. Of at least 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, and one side of the sphere is rotatably held while being exposed from the socket. Because of this configuration, the swing angle of the arm can be increased. Further, since the two arms are biased 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 drawings]

FIG. 1 is a perspective view of a parallel robot of this embodiment.

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

FIG. 3A for the parallel robot of this embodiment, which corresponds to FIG.
It is an arrow view.

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

FIG. 5 is an enlarged view of an arm tip of this embodiment.

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

[Explanation of symbols]

 1 Base 2 Bracket 11 Support 31 Arm 41 Motor 51, 61 Ball Joint 71 Link 72 Rod 91 First Joint 91a Sphere 90 Second Joint 90a Socket 93 Spring

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor François Pierrot France, 34070 Montpellier 1 En 5 Luangpert 261 (72) Inventor Osamu Sotoyama 1-1 Asahi-cho, Kariya city, Aichi prefecture Toyota Koki Co., Ltd.

Claims (1)

[Scope of utility model registration request] 1. A pair of six arms consisting 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 each of the six arms. A parallel robot having a section, a bracket in which the tips of the six arms are mounted on the same plane by a second ball pair, and six motors for individually swinging the six arms. At least the second ball pair of the first 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 of being exposed from the socket, and the two arms supported by the supporting portion are urged by elastic members in a direction of pressing the sphere toward the socket. A parallel robot featuring.