JPS587436B2 - Actuator for industrial robots - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rotary actuator for a teach/regenerate industrial robot, and is intended to reduce the movement of a working arm during manual teaching operations.

Needless to say, in this type of robot, it is preferable for the working arm to be able to be manually and easily moved during the teaching operation, in order to ensure accurate positioning and to ease the burden on the operator.

By the way, the above-mentioned rotary actuators are generally small and
Since a lightweight device with a high torque capacity is desired, it is often used in combination with a speed reduction mechanism, but with this device, it is impossible to easily perform manual teaching operations from the output side.

The present invention aims to reduce the movement of a rotary actuator incorporating a speed reduction mechanism as described above during teaching operation, and uses a harmonic speed reduction mechanism as the speed reduction mechanism and a clutch mechanism in the speed reduction mechanism. It is characterized by the fact that it has been provided.

The present invention will be specifically described below with reference to illustrated embodiments.

In Fig. 1, reference numeral 2 denotes a housing incorporating a harmonic reduction mechanism, and a rotary drive device 1 is provided on the upper part of the housing 2, and an output shaft 4 of the drive device 1 is connected to the harmonic reduction mechanism. A drive shaft 12 for the working arm 3 connected to the harmonic reduction mechanism is provided at the lower part of the shaft.

The output shaft 4 and the drive shaft 12 are arranged concentrically and at opposing positions.

The harmonic reduction mechanism is as follows.

That is, the center of an elliptical plate-shaped web generator 6 is fixed around the end of the output shaft 4 via a boss 5, and a ball bearing 7 is provided on the outer periphery of the web generator 6.

Each ball 7a housed in the cage 7b of the ball bearing 7 is movable in the radial direction as the ellipsoidal web generator 6 rotates.

The upper end outer periphery of a cup-shaped flex spline 8 is arranged on the outer periphery of the ball bearing 7.

As is well known, the flex-spline 8 is flexible and has external teeth 8c on the outer periphery of the upper end of the cylindrical portion 8a, as best shown in FIG.

This flex spline 8 can be easily deformed as each ball 7a of the ball bearing 7 moves in the radial direction.

A circular spline 18 having internal teeth 18a on a circle is provided on the outer periphery of the external teeth 8c of the cylindrical portion 8a of the flex-spline 8.

The internal teeth 18a mesh with the external teeth 8c in the longitudinal direction,
They are separated in the short axis direction.

The internal teeth of this circular spline 18 have about two more teeth than the internal teeth 8c of the flex spline 8, and mesh with the external teeth 8c in the long axis direction, but do not mesh with this in the short axis direction. .

Further, the circular spline 18 is rotatably supported between the main body 2a of the housing 2, the cylindrical holder 9 built into the main body 2a, and the lid 2b of the main body.

The bottom portion 8b of the flex-spline 8 is fixed to the drive shaft 12.

The harmonic speed reduction mechanism is as described above, and the clutch mechanism including the holder 9 is structured as follows.

That is, a hydraulic transmission member 13 having a hydraulic passage 14 is provided on the side surface of the housing 2, and a hydraulic passage 21 communicating with the hydraulic passage 14 is formed in the housing 2, and the passage 21 accommodates the holder 9 so as to be vertically movable. The lower part of the cavity 22 formed in the housing 2 is opened.

A hydraulic device (not shown) is connected to a pressure oil supply port of the hydraulic passage 14 of the hydraulic pressure transmission member 13 .

Therefore, the hydraulic system causes pressure oil to flow into the hydraulic passage 14.21.
When the holder 9 is supplied to the cavity 22 through the holder 9, the holder 9 is lifted upward and holds the circular spline 18 non-rotatably between its upper surface and the lid 2b.

On the other hand, when the pressure oil is removed from the cavity 22, the holder 9
returns to the state shown in FIG. 1 and releases the circular spline 18, allowing it to rotate freely.

Now, when the drive device 1 is operated with the circular spline 18 fixed by the clutch mechanism, the output shaft 4 thereof rotates together with the boss 5 and the web generator 6.

Then, since the web generator 6 is formed into an elliptical plate shape, each ball 7a of the ball bearing 7 is sequentially moved in the radial direction, while the circular spline 18
is fixed, and when the circumference of the upper end of the cylindrical portion 8a of the flex-spline is forcibly deformed in the radial direction by each ball 7a, the external teeth 8c in the longitudinal direction and the circular
As the meshing with the internal teeth of the spline 18 moves, the flex spline 8 is moved by the difference in the number of teeth between the external teeth 8c and the internal teeth L8a, for example, by two teeth, per one rotation of the web-gear lator 6. It rotates in the opposite direction, causing the drive shaft 12 and the working arm 3 to rotate at a reduced speed.

The above operation is a reproducing operation, but the teaching operation is performed as follows.

First, the pressure oil in the cavity 22 of the housing 2 is removed by the hydraulic system, the holder 9 is released from the circular spline 18, and the circular spline 18 becomes rotatable.

In this state, when the working arm 3 is rotated according to the teaching contents, the circular spline 18 can freely rotate, so the flex spline 8 is rotated through the drive shaft 12.
It rotates around the ball bearing 7 together with the circular spline 18.

This teaching operation can be performed manually and extremely easily.

The rotation of the drive shaft 12 based on the teaching operation is detected by a rotation angle detection device (not shown) via a pulley 17 fixed around the shaft and a transmission means (not shown) connected to the pulley 17.

The reproducing operation is performed according to the rotation angle detected by this rotation angle detection device.

In the figure, 10 is an O-ring that is fitted as a piston into the inner and outer peripheries of the holder 9 and seals between the wall surface of the cavity 22, 15 is a bearing for the drive shaft 12, and 11 is the outer periphery of the drive shaft 12. This is a spacer provided in the

The drive device 1 in the above embodiment may be of any type such as hydraulic, pneumatic, or electric.

In the embodiment described above, the clutch mechanism is constituted by a hydraulic clutch, but the present invention is not limited to this embodiment, and other configurations such as an electromagnetic clutch may be used.

Further, the ball bearing 7 can also be a bearing incorporating rollers.

As is clear from the specific description of the above embodiments, the actuator for an industrial robot according to the present invention includes a harmonic reduction mechanism provided between the output shaft of the drive device and the drive shaft for driving the working arm, and a circular speed reduction mechanism of the harmonic reduction mechanism. Since a clutch mechanism is provided to fix and release the spline, during the teaching operation, the connection between the drive shaft for driving the working arm and the output shaft of the drive device can be severed by releasing the fixation of the circular spline using the clutch mechanism. The working arm can be manually operated together with the drive shaft very easily.
You can achieve your intended purpose.

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional view of an actuator for an industrial robot according to an embodiment of the present invention, and FIG. 2 is an explanatory cross-sectional view showing a harmonic reduction mechanism adopted in the actuator of FIG. 1 in a plan view. . 1... Drive device, 2... Housing,
4... Output shaft, 6... Web generator, 7... Bearing, 8... Flex spline, 8c... External teeth , 9...
Holder, 12... Drive shaft, 18...
Circular spline, 18a...internal tooth.

Claims (1)

[Scope of Claims] 1. A harmonic reduction mechanism is provided between an output shaft of a drive device and a drive shaft for driving a working arm that is concentric with and faces the output shaft, and an elliptical plate shape is provided at an end of the output shaft. The center of the web generator is fixed, and a bearing is interposed on the outer periphery of the web generator to allow balls or rollers to move in the radial direction as the web generator rotates.
The bottom end of a cup-shaped flex-spline is fixed to the end of the drive shaft, and the outer periphery of the upper end thereof having external teeth is arranged around the bearing, and the flex-spline is fixed to the outer periphery of the upper end of the flex-spline. A circular spline is provided which has internal teeth on a circle that mesh with a part of the external teeth of the flex-spline to decelerate and rotate the flex-spline in a direction opposite to that of the web generator when the web generator rotates. A clutch mechanism is provided to freely fix and release the circular spline, and when the working arm is rotated together with the drive shaft during the teaching operation, the clutch mechanism releases the circular spline, and the flex spline locks into the circular spline. - An actuator for an industrial robot characterized by rotating with respect to a web generator together with a spline.