JPH0429987Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to the structure of a joint portion of an operating arm of an industrial robot or the like.

2. Description of the Related Art A reduction mechanism that is lightweight and has a high reduction ratio is generally incorporated in the joint portion of the operating arm of an industrial robot, particularly in the wrist portion provided at the tip thereof.

Figure 2 shows Harmonic Drive (registered trademark)
1 is a sectional view of the main parts of a conventional example in which a speed reducer having a gear mechanism called .

Reference numeral 1 denotes a robot arm, which is connected to the main robot side (not shown), and constitutes a kind of joint mechanism 5 that rotates the wrist 4 by a drive shaft 2 via a deceleration mechanism 3.

The speed reduction mechanism 3 is composed of a web generator 6, a circular spline 8, and a flex spline 7 located between the web generator 6 and the circular spline 8 and having a gear 7a that engages with the circular spline. The connecting part between the flex spline 7 of the reducer and the wrist 4 is connected to the main bearing 9.
It is rotatably supported by a joint support ring 8 fitted with the joint part support ring 8.

Numerals 10 and 11 are mounting bolts on the robot arm side and wrist side, respectively, and are arranged in an appropriate number depending on the strength.

Note that a tool is attached to the tip of the wrist 4 depending on the purpose of use, and this figure shows a spot welding tip attached.

Problems to be Solved by the Invention However, in such conventional devices, the main bearing 9 cannot be directly attached to the reduction mechanism, and is installed separately from the reduction mechanism as shown in Fig. 2. It was necessary to provide a joint support ring 8 and the like on the body, and to provide a bearing (main bearing 9 in FIG. 2) for supporting the wrist on the outside of the deceleration mechanism.

For this reason, even if the comparatively lightweight Harmonic Drive (registered trademark) speed reduction mechanism as described above is used, the length L of the joint mechanism section 5 becomes large.
The length of the tip of the robot arm including the wrist 4 becomes longer, and the weight of the robot arm becomes heavier.

Moreover, as the length L of the joint mechanism section 5 increases, the bending moment applied to the joint mechanism attachment section and the arm increases, and special design consideration is required in terms of strength. It had the following drawbacks.

It is an object of the present invention to solve the problems associated with the robot arm joint mechanism in the prior art and to provide a robot arm joint mechanism that is compact and has a short installation length.

Means to Solve the Problems This invention connects the wrist of the robot directly to the bearing plate of the housing for the internal gear of a plano-eccentric type reduction mechanism that has an oscillating external gear using an eccentric input shaft. However, by providing the main bearing in the deceleration mechanism itself, supporting members such as a wrist support ring at the joint can be omitted, and a lightweight joint mechanism with a short installation length can be obtained.

Examples Hereinafter, the configuration of the present invention will be specifically explained using examples.

FIG. 1 is a main cross-sectional view of a robot arm joint mechanism showing an embodiment of the present invention, and parts having the same configuration or function as those in FIG. do.

The speed reducer 3 attached to the tip of the robot arm 1 of this embodiment is a plano eccentric type speed reducer, and includes a first speed reducer 3a that is attached to the drive shaft 2 and consists of an input gear 2a and a driven gear 2b.
and two external gears 3 that perform rocking motion by a crankshaft 3c that acts as an eccentric input shaft.
2, 33, and a second speed reduction mechanism 3b comprising a housing 34 provided with an internal gear 31 having a pin structure.

15 is a first bearing plate having a bearing 14 for the crankshaft 3c as an eccentric input shaft that rotates via the first speed reduction mechanism 3a;
2 and 33, and which supports a housing 34 provided with an internal gear 31 that engages with these gears by bearings 17a and 17b. Bearing 17a, 1
A well-known angular bearing is used as the bearing 7b, but in this embodiment, a cross roller bearing is used as the main bearing for the bearing 17a, and a radial ball bearing is used as the auxiliary bearing for the bearing 17b.

In addition, if the load moment on the wrist is small,
The main bearing 17a alone is sufficient. The bearing plate 1
6 is further provided with a bearing 19 for the crankshaft 3c, and the first bearing plate 15, second bearing plate 16, and wrist flange 4a are connected by mounting bolts 18.
This allows them to be integrally connected.

With the above configuration, a joint mechanism is constructed by directly connecting the internal gear housing of the speed reduction mechanism to the arm side tip of the robot and directly connecting the second bearing plate having the main bearing 17a to the wrist side. This is possible.

Therefore, the rotation of the drive shaft 2 causes the external gears 32 and 33 of the plano eccentric type speed reduction mechanism, which is the second speed reduction mechanism, to swing through the crankshaft of the first speed reduction mechanism 3a. The second deceleration mechanism
The bearing plate 16 is rotated at a reduced speed relative to the internal gear housing.

This motion becomes a joint motion that directly rotates the wrist 4 of the robot arm.

Effects of the invention According to the invention, the main bearing 17a of the reduction mechanism itself can be used as the main bearing for the joint.
There is no need to separately provide a support member such as a joint support ring as in the past, and there is no need to provide a main bearing for the joint separately from the speed reduction mechanism. In other words,
The deceleration mechanism itself can be used directly as a robot joint mechanism.

Therefore, the length of the joint mechanism 5 between the arm tip and the robot wrist can be shortened.
In addition, the weight of the arm tip can be reduced and the bending moment associated with it can be reduced, and the structure of the joint mechanism is simple, making assembly work extremely easy.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of the main parts of the embodiment of the present invention;
The figure is a sectional view of the main parts of a conventional example. 3c...Eccentric input shaft (crankshaft), 4
... wrist, 5 ... joint mechanism, 15 ... first bearing plate, 16 ... second bearing plate, 32, 33 ... external gear, 34 ... carrier for internal gear.

Claims (1)

[Scope of utility model registration request] a first bearing plate having a bearing for an eccentric input shaft;
In a plano eccentric type speed reduction mechanism having a housing provided with an external gear oscillated by the eccentric input shaft and an internal gear engaged with the external gear, A joint mechanism for a robot, characterized in that a wrist of the robot is directly connected to a second bearing plate having a bearing.