JPS60232893A - Driving mechanism of wrist for industrial robot - Google Patents

Abstract

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

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to an improvement in a drive mechanism for the arm and wrist of an industrial robot.

[Background of the invention]

Conventionally, the drive mechanism of a robot consists of a disk 1, a pivot shaft 3, and a rod 2 using parallelogram links as shown in Figure 1.
Therefore, there was a mechanism for transmitting the angular change O. A more practical study of this mechanism is U.S. Patent No. 41343.
It is shown in the specification of No. 07.

In the above-mentioned patent, by adding a device to the pivot shaft 3, the angular change shown in FIG. 1 can be transmitted by a little less than 360 degrees. However, it was impossible to transmit rotations of 360" or more. Figure 2 shows a conventional example (Special Publication Publication No. 57) in which a sprocket [a] chain 2a is combined for transmission in order to cover the drawbacks of the one shown in Figure 1 above. -66884).This made it possible to transmit continuous rotation, but the accuracy deteriorated due to elongation of the chain 2a over time and wear that occurred between the sprocket h1a and the adjustment of the tension of the chain 2a. There were drawbacks such as the need for

In order to further overcome the drawbacks shown in FIG. 2, there is a conventional example (Japanese Patent Publication No. 57-668 G4) using a transmission shaft 2b using a bevel gear as shown in FIG. This eliminated problems such as chain elongation, but on the other hand, new problems such as gear machining, tooth surface wear, backlash adjustment, and increased machining costs occurred.

[Purpose of the invention]

The object of the present invention is to eliminate the above-mentioned drawbacks, to enable transmission of continuous rotation, to be lightweight, compact, have a small number of parts, and to have high rigidity, less play, and easy adjustment of the wrist of an industrial robot. The goal is to provide a mechanism.

[Summary of the invention]

In order to drive a wrist drive section of an industrial robot, this invention configures a wrist drive mechanism by combining a wrist drive section, a transmission section, a transmission section, and a drive section. This feature is characterized in that the connection is mounted via a universal joint, which reduces the need for complicated shaft support parts, resulting in a simple structure.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described based on FIG. 5 and subsequent figures.

In FIG. 5, the upper arm A and the forearm B form a shoulder joint axis a, an elbow joint axis b, and a wrist bending joint axis C.

Wrist end flange 4 is universal constant velocity joint 5.9
, 13, and the shaft 7.11.1 constituting the transmission section.
4, it is connected to a speed reducer 15 of the transmission section and a drive motor 16 of the drive section. Universal constant velocity joint 5
, 9.13 exist on the wrist bending joint axis C1, the elbow joint axis b, and the shoulder joint axis a, respectively. Next, the rotational movement of the wrist portion 17 around the axis C is connected to a reduction gear 29 and a drive motor 30 via shafts 18, 21, 25, 28 and universal constant velocity joints 19, 23, 27. Universal constant velocity joints 19, 23° 27 are connected to axes C and b, respectively.
, exists on a. With this arrangement, the wrist tip flange 4 can maintain its posture regardless of the movements of the upper arm A and forearm B, that is, no matter what movements the upper arm A and forearm B make.

FIG. 6 shows another embodiment in which the reducers 15 and 29 in FIG. 5 are moved to 15a and 29a. With this arrangement, universal constant velocity joints 5, 9, 1
3, 19, 23.27 and shaft 7.11, 14, 18
, 21.25 and bearing 6.8.10.12.20.22
．． 24.26, the rotational speed is somewhat higher than that in Figure 5, but the required torque is significantly lower, so the shaft diameter can be reduced and the strength can be lowered, making it even lighter and more compact. In FIG. 6, the disk 1, rod 2, and pivot shaft 3 shown in FIG. 1 are provided to maintain the posture of the wrist bending joint axis C.

FIG. 7 shows a wrist drive mechanism with three degrees of freedom by adding one more degree of freedom.

The output of the drive motor 16 is transmitted to the twist shaft d via the universal constant velocity joint 13, 9.5 and the reducer 15a.
is driven. The bending axis C is driven by the drive motor 30 via the universal constant velocity joints 27, 23.19 and the speed reducer 29a. The swing axis e is driven by a drive motor 44 to a universal constant velocity joint 43,
41° 39.37, 35.33 and is driven via a reduction gear 32. In this case, universal constant velocity joint 5
, 33, 35.37 form a parallelogram, the swing axis e
There is no mutual interference between the motions of the other bending axes C and twisting axes d. Also in FIG. 7, a disk 1, a rod 2, and a pivot shaft 3 are used to maintain the posture of the bending axis C. Fig. 8 shows the position of the drive motor 16 for the twist axis C and the drive motor 44 for the swing axis e being changed, and the location of the drive motor 16 for the twist axis C and the drive motor 44 for the swing axis e being changed, The universal constant velocity joint 5 (Fig. 7) that was in the model was abolished.
Universal constant velocity joints 5a, 5T) and 5C are used instead.

By adopting this arrangement, it is possible to prevent excessive internal force from being generated even if the shaft between the 7-speed universal joints expands and contracts thermally.

In the above, the drive motor 16, 30.44 is connected to the shoulder joint axis a.
In this example, they are placed on or near the elbow joint axis, but it is also possible to place them on or near the elbow joint axis. Further, each drive motor can be arranged on or near the rotation axis C1, the twist axis d, and the swing axis a.

〔Effect of the invention〕

With the above configuration, the present invention will be described in detail. By interposing a universal joint in the shaft connection part of a plurality of transmission parts, the wrist drive part can be quickly operated even for movements with two or more degrees of freedom. In addition, costs can be reduced by not requiring expensive gears and by significantly reducing the number of shaft supporting parts involved.

Also, the noise caused by rotation can be reduced by eliminating the gear part.

Additionally, the arrangement of multiple universal joints simplifies manufacturing, making it more compact and reducing weight more than expected.

[Brief explanation of the drawing]

Figures 1 to 4 are internal structure diagrams showing a known example, Figure 5 is a link diagram of one embodiment, Figure 6 is a link diagram with the parts arrangement changed from Figure 5, and Figures 7 and 8. is a link diagram showing another embodiment in which FIGS. 5 and 6 are extended to three degrees of freedom. 1... Disk, 2... Rod, 3... Pivoting shaft, 5,
9゜13.19,23,27,33,35,39゜41
．． 43...Universal constant velocity joint, 15a. 29a, 32-Reducer, 16.30.44. , - drive motor. -11~

Claims (1)

[Claims] 1. In the wrist drive mechanism of an industrial robot, which has a function with more than 2 degrees of freedom and is composed of a wrist part, a wrist drive part, a speed change part, a drive part, and a transmission part, it is a versatile shaft connecting part of multiple transmission parts. A wrist drive mechanism for an industrial robot characterized by a joint. 2. In the wrist drive mechanism for an industrial robot according to claim 1, the transmission section is