JPS6076988A - Joint type robot - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to an articulated robot, and more particularly to an improvement in a joint drive mechanism of an articulated robot.

PRIOR ART AND PROBLEMS A base of a first arm is pivotally attached to a robot body so as to be rotatable along a vertical plane, and a first arm driving device for rotationally driving the first arm is provided on the robot body. In an articulated robot in which the second arm is pivotally attached to the tip of the second arm so as to be rotatable along a vertical plane, the range of motion of the output end of the robot, that is, the tip of the wrist provided at the tip of the second arm is widened. In addition, it is desired to reduce the load applied to the arm drive device as much as possible.

1 and 2 show the structure of a conventional general articulated robot using a parallelogram link mechanism.

Referring to this figure, the robot body 1 has a first arm 2.
The base of the first arm 2 is pivotably mounted around an axis C1 along a vertical plane so as to be rotatable in the W direction, and the tip of the first arm 2 has a second
The middle part of the arm 3 is U around the axis C2 along the vertical plane.
It is pivoted so that it can rotate in the direction. A wrist portion 4 is provided at the tip of the second arm 3. One end of a first link 5 having the same size as the first arm 2 is connected with a pin to the rear part of the 27th arm 3, and a second link 6 connected with a pin to the other end of the first link 5 is on the axis C1. is pivotally connected to the first arm 2 to form a parallelogram link mechanism. As shown in FIG. 2, a first arm drive motor 7 and a second arm drive motor 7 for rotationally driving the first arm 2 with respect to the robot body 1 are provided on the axis C1.
A second arm drive motor 8 for rotationally driving the arm 3 relative to the first arm 2 is provided. The driving force of the second arm drive motor 8 is applied to the second link 6 and the first link.
The signal is transmitted to the second arm 3 via the link 5.

In the case of a conventional articulated robot using such a parallelogram link mechanism, the load (moment about the axis C1) applied to the first arm drive motor 7 is determined by the angle of the 17th arm 2 and the weight of the second arm 3. Since the angle of the second arm 3 with respect to the first arm 2 does not depend on the angle of the second arm 3 with respect to the first arm 2, fluctuations in the load on the first arm drive motor 7 due to movement of the center of gravity of the arm become relatively small. Furthermore, since the second arm 3 can be rotationally driven by driving the second auxiliary link 6 with the second arm drive motor 8 provided on the axis C1, the load applied to the first arm 2 can be reduced. This means that the load applied to the first arm drive moke 7 can be reduced.

However, in the case of the above conventional structure, since a parallelogram link mechanism is used, the angle θ formed by the 27th beam 3 and the 17th beam 2 is greatly limited, and in reality, the limit is about 100°. . Therefore, there is a drawback that the degree of freedom of movement of the output end of the robot, that is, the tip of the wrist is narrowed.

Purpose of the Invention In view of the above-mentioned drawbacks of the prior art, the present invention provides a structure in which the base of a first arm is rotatably mounted on a robot body so as to be rotatable along a vertical plane, and the first arm is rotatably driven on the robot body. A first arm drive device is provided to drive the second arm, and a second arm drive device is provided at the tip of the second arm.
In an articulated robot in which the arm is rotatably pivoted along a vertical plane, the operating range of the wrist distal end provided at the output end of the robot, that is, the tip of the second arm, can be widened, and the arm drive device The purpose of the present invention is to provide an articulated robot that can reduce the applied load as much as possible.

According to the present invention, the base of the first arm is pivotally attached to the robot body so as to be rotatable along a vertical plane, and the first arm is rotatably driven to the robot body. In an articulated robot in which a single arm drive device is provided and the second arm is pivotally attached to the distal end of the second arm so as to be rotatable along a vertical plane, the second arm is mounted on the axis of the pivot portion of the second arm and The first arm is connected to a second arm driving device via rotation transmitting members located on the axis of the pivot portion of the first arm, and the robot body and the first arm are connected to each other depending on the inclination angle of the first arm. This is achieved by an articulated robot characterized by being equipped with a gravity balancer that performs gravity compensation.

Embodiment of the Invention Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 3 to 6 of the drawings.

Referring to FIG. 3, the articulated robot includes a robot body 12 that is provided on a machine base 11 so as to be rotatable in the horizontal direction, and the base of the first arm 13 is attached to the robot body 12 in a vertical plane. It is pivotally mounted so as to be rotatable in the W direction around an axis 01 along. At the tip of the first arm 13 there is a 27th arm 1.
4 is pivotally mounted along a vertical plane around an axis C2 so as to be rotatable in the U direction. The tip of the second arm 14 has a wrist portion 1.
5 is provided. Although not particularly limited, the wrist portion 15 here includes a wrist base portion 15a that is rotatable in the γ direction with respect to the 27th arm 14, and a wrist intermediate portion that is rotatable in the β direction with respect to the wrist base portion 15a] 5b, and a wrist distal end portion 15c that is rotatable in the α direction with respect to the wrist intermediate portion 15b. Although not shown, motors for driving the wrist portion 15 in the α direction, β direction, and γ direction can be provided on the second arm 14, respectively.

Referring to FIG. 4, the first arm 13 is connected to the robot body 1.
2 through hair rings 16, 17 so as to be rotatable around the axis C1. In an example of the 17th arm 13, the robot body 12 has a first arm drive motor 1.
8 is attached. The output shaft 18a of the motor j8 is connected to the first arm 1 via a reducer 19 which also serves as a rotation transmission mechanism.
It is connected to the base of 3.

Although not particularly limited, the reducer 19 is made of what is called a harmonic drive (registered trademark) in MIKO, and this reducer 19 is connected to the wave generator 2o.
and flexspline 21 and circular spline 22
It consists of

As shown in FIG. 5, the wave generator 2° has an oval cam 20a fixed to the output shaft 18a of the motor 18.
The ball hair ring 20b fitted on the outer periphery of the ball bearing 20b is sharp, and the inner ring of the ball bearing 20b is connected to the cam 2.
Although it is fixed at 0a, the outer ring can be elastically deformed via the balls. A flexspline 21 made of a thin cup-shaped elastic metal body is fitted into the outer ring of the ball bearing 20b, and teeth are formed on the outer periphery of the flexspline 21.

On the inner periphery of the ring-shaped circular spline 22, the same pinch of teeth as the teeth of the flexspline 21 are formed in the circumferential direction, and the number of teeth of the circular spline 22 is slightly smaller than the number of teeth of the flexspline 2■. (for example, 2). The circular spline 22 is fixed to the robot body 12, and the end plate 23 provided integrally with the flexspline 21 is connected to the 17th section 13 on the axis C1.
is fixed at the base of. When the output shaft 18a of the motor 18 rotates clockwise around the axis C] in the clockwise direction in FIG. Circular spline 22 on the shaft
The meshing position moves as the wave generator 20 rotates. wave generator 2
0 rotates once, the flexspline 21 moves counterclockwise by the difference in the number of teeth from the circular spline 22. As a result, when the number of teeth of the flexspline 21 is Zf and the difference in the number of teeth is d, the reduction ratio becomes -d/Zf, and a reduction output is obtained around the axis C1. This deceleration output is transmitted to the first arm 13.

Referring to FIG. 4, the second arm 14 is the 17th arm]3
The second arm 14 and the first arm 13 are rotatably supported around the axis C2 via a bearing 24, and a reducer 25 which also serves as a rotation transmission mechanism is provided along the axis C2. It is being This speed reducer 25 has the same structure as the speed reducer 19 described above. The flexspline 26 of the reducer 25 is connected to an end plate 27 fixed to the second arm 14.
It is formed integrally with the circular spline 28.
is fixed to the first arm 13, and the first arm 13 is rotatably supported by the gear mechanism rake 29.
It is fixed to the shaft 3o. A bevel gear 3I is fixed to the first shaft 30 within the seventeenth arm 13.

A second shaft 32 extending in the longitudinal direction of the first arm is provided in the first arm 13 so as to be rotatable around its longitudinal axis, and one end of the second shaft 1.32 meshes with a bevel gear 31. A bevel gear 33 is fixed. Another bevel gear 34 is fixed to the other end of the second shaft 32.

A third shaft 35 located on the axis C1 is rotatably supported on the robot body 12 via hair rings 36 and 37, and a bevel gear meshed with the bevel gear 34 of the second shaft 32. Gear 38 is fixed. The third shaft 35 is coupled to an output shaft 39a of a second arm drive motor 39 fixed to the robot body 12.

Therefore, the rotational driving force of the motor 39 is transmitted to the second shaft 3.
2 and the speed reducer 25 to the second arm 14.

A gravity balancer 40 is provided between the robot trunk 12 and the first arm 13 for performing gravity compensation according to the inclination angle of the first arm 13.

The gravity balancer 40 here includes a cylinder 41, a piston rod 42 and a coil spring 43. The lower end of the piston rod 42 is supported by the robot body 12 via a support pin 44 above the axis C1. The upper end of the piston/mouth/throat 42 is inserted into the cylinder 41, and the upper end of the cylinder 41 is connected to the first arm 13 via the support pin 45 on the longitudinal axis of the first arm 13.
is supported by Although not particularly limited, here,
The support bin 45 is located on the intersection with the axis C2. The cylinder 41 and piston rod 42 are biased in the contraction direction by a coil spring 43.

In the articulated robot having the above configuration, the first arm 13
When the arm is tilted from the vertical position by the driving force of the motor 18, the load moment on the motor 18 due to the weight of the arm increases as the center of gravity shifts, but as shown by the two-dot chain line in FIG. Since the coil spring 43 is expanded and compressed, a spring force in the direction of contraction acts between the support pins 44 and 45. This spring force applies a moment to the output shaft 18a of the motor 18 in the opposite direction to the moment due to the weight of the arm, and as a result, the amount of increase in the load moment on the output shaft 8a of the motor 18 is reduced. Become. Since the spring force of the gravity balancer 40 is approximately proportional to the inclination angle of the first arm 13, gravity compensation can be performed in accordance with the inclination angle of the first arm 13.

Since the gravity balancer 40 does not interfere with the movement of the second arm 14, the second arm 14 can be freely moved within a range that does not interfere with the first arm 13. In reality, the second arm 14 can be rotated by 180 degrees or more relative to the first arm 13.

In the articulated robot having the above configuration, the second arm drive motor 39 is connected to the second arm 14 via rotation transmission mechanisms provided on the axis C1 and the axis C2, respectively. does not act on the first arm 13.

Therefore, the load applied to the first arm drive motor 18 is reduced.

Although one embodiment has been described above, the present invention is not limited to the embodiment described above, and various changes can be made within the scope of the invention as set forth in the claims.

Effects of the Invention As is clear from the above description, the present invention provides a structure in which the base of the first arm is pivotally attached to the robot body so as to be rotatable along a vertical plane, and the first arm is rotatably attached to the robot body. In the articulated robot-nod, the second arm is provided with a first arm drive device, and the second arm is pivotally attached to the tip of the second arm so as to be rotatable along a vertical plane. The first arm is connected to a second arm driving device via rotation transmission members located on the pivot axis and on the pivot axis of the first arm, respectively, and the first arm is connected between the robot trunk and the first arm. This robot is characterized by a gravity balancer that performs gravity compensation according to the inclination angle of the robot. In addition to being able to expand compared to articulated robots using link mechanisms,
This makes it possible to provide an articulated robot that can reduce the load applied to the first arm drive device.

[Brief explanation of drawings]

Fig. 1 is a front view of a conventional articulated robot using a parallelogram link mechanism, Fig. 2 is a side view of the robot shown in Fig. 1, and Fig. 3 is an articulated robot showing an embodiment of the present invention. FIG. 4 is a longitudinal sectional view of the main part of the robot shown in FIG. 3, and FIG. 5 is a schematic perspective view of the robot shown in FIG. 3.
6 is a diagram illustrating the operation of the gravity balancer of the robot shown in FIG. 3; 12-Robot trunk, 13-First arm, 14-Second arm, 18-First arm drive moke, 19.25-Reduction gear, 39-Second arm drive motor, 40-Gravity balancer. Patent Applicant Fanasoku Co., Ltd. Patent Application Agent Akira Aoki Patent Attorney Nishidate Wazai Patent Attorney Nishioka Bema Patent Attorney Akira Yamaguchi Patent Attorney Masaya Hyode

Claims (1)

[Claims] 1. The base of the first arm is pivotally attached to the robot body so as to be rotatable along a vertical plane, and the first arm is pivotably attached to the robot body.
A first arm drive device for rotationally driving the arm is provided, and a second arm drive device is provided to rotate the arm.
In an articulated robot in which a second arm is rotatably attached to the tip of the arm along a vertical plane, the second arm is arranged on the axis of the pivot of the second arm and on the axis of the pivot of the first arm. A gravity balancer is provided between the robot body and the first arm, the gravity balancer being connected to the second arm driving device via rotation transmission members located at the respective positions, and performing gravity compensation according to the inclination angle of the first arm. An articulated robot characterized by: 2. In the articulated robot t according to claim 1, the gravity balancer is a first arm supported by the robot throat body above the axis of the pivot part of the first arm.
a second member supported by the first arm on a longitudinal line of the first arm; and spring means for biasing the first member and the second member in the contraction direction. Features: Articulated robot.