JPS59175986A - 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 Industrial Application The present invention relates to an industrial robot that absorbs vibrations generated by a differential speed reducer (hereinafter referred to as Harmonic Drive (trade name)).

Conventional configurations and their problems Traditionally, industrial robots have often used harmonic drives as their reduction gears.

Figure 1 shows the configuration of a conventional industrial robot.
1 is the first arm, 2 is the second arm, 3 and 4 are the motors, 5
, 6 are harmonic drives, and motors 3., 6 are harmonic drives. The first arm 1 is moved by the Moninoku drive 5, and the motor 4. The second arm 2 is driven to rotate by the harmonic drive 6.

Figures 2 and 3 show the structure of the harmonic drive. 7 is a circular spline, 8 is a flex spline, and the flex spline 8 has a few fewer teeth than the circular spline 7. In addition, the flexspline 8 is a thin shell-like structure,
The ram easily deforms elastically due to external force. 9 is a web generator, which has an oval shape and has a flex spline 8.
has an elliptical shape along the outer circumference of the web generator 9. When the web generator 9 rotates, the flexspline 8 deforms along the outer circumference of the web generator 9, so the occlusion point between the circular spline 7 and the flexspline 8 moves in synchronization with the rotation of the wafer generator 9, and when the wafer generator 9 makes exactly one revolution, the flex spline 8 has fewer teeth than the circular spline 7, so the difference between them makes them relatively This will cause a misalignment. This is the deceleration mechanism of the Nohaemony Drive.As mentioned above, the Nohaemony KuDryf has the unique feature of being able to obtain a large reduction ratio with a small size in terms of its structure. , has the following drawbacks. One is that the flex spline 8 has low rigidity due to its structure.

That is, the flex spline 8 itself is an elastic body.Another problem is that it is likely to cause torque unevenness and vibration due to the cutting accuracy of the circular spline 7.

Therefore, when a harmonic drive is used in an industrial robot, the vibrations generated by the harmonic drive are amplified by the elasticity of the harmonic drive, which often poses a problem.

Therefore, software-servo technology that applies microcomputer technology has been attracting attention in recent years. This is a feedforward system that uses a microcomputer to perform servo control, which has traditionally been performed using analog circuits.By inputting the mechanical characteristics of the industrial robot into memory in advance, the robot's movements are predicted and corrected using feedforward. It becomes possible to perform sensor foot control, which makes corrections based on information from various sensors attached to industrial robots. Therefore, by using software servo, it is possible to solve the vibration caused by the harmonic drive.

However, although software servo has an advantage over analog servo in terms of functionality, it also has cost and
In terms of reliability, it is currently inferior to analog servos, and efforts are being made in various places to find a solution to the vibration caused by monolithic drives using mechanical methods in addition to control methods. .

Purpose of the Invention The present invention focuses on the fact that a structure having two elastic bodies has vibration absorbing properties, and attempts to mechanically resolve the vibrations caused by the monic drive of an industrial robot. Structure of the present invention In order to configure another elastic body in addition to the flex spline of the harmonic drive, a timing belt is provided between the motor and the harmonic drive, and the tension reinforcement system is configured using elastic bodies on both sides of the timing belt. By providing a mechanism, vibrations generated by the harmonic drive are absorbed.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

Fig. 4 shows the configuration of an industrial robot according to the first embodiment of the present invention, where 1o is a first arm, 11 is a second arm, 12, 13 is a motor, and 14° and 16 are harmonic drives. , motor 12. The harmonic drive 14 drives the first arm 1Q, and the motor 13. The second arms 11 are each driven to rotate by a harmonic drive 16.

5, 6 U, motor 12. This is an enlarged view of the harmonic drive 140, where 16 is a timing pulley attached to the output shaft of the motor 12, 17 is a timing pulley attached to the input shaft 18 fixed to the web generator 14c of the harmonic drive 14, and 19 is a timing pulley. A belt, 20 is a bearing that supports the input shaft 18, 21 is a bracket fixed to the first arm 10 and fixes the circular spline 14a of the monochrome drive 14, and 22 is the 7th gear of the monochrome drive 14. It is fixed to the robot base 23 with a racket that fixes the cross spline 14b.

24 is the first arm 10. A bearing that rotatably supports the bracket 21 relative to the robot base 23, 25 is a bearing that can swing around a fulcrum, and 26 is a lever 26.
The bearing 27 rotatably provided at the tip of the timing belt 19 is a spring provided so that the bearing 26 presses the timing belt 19 from the outside.

In the above configuration, when the tension on the X side of the timing belt 19 increases when vibration occurs due to torque unevenness in the drive 14, the lever 26 moves in the directions of arrows A and C, respectively. Conversely, when the tension on the Y side of the timing belt 19 increases, the levers 25 move in the force directions of arrows B and D, respectively. That is, when the tension on the X side of the timing belt 19 increases, on the X side,
When the tension on the Y side increases, it has the same effect as elongation on the Y side.

The above configuration is schematically shown in FIG. 7.

In FIG. 7, the spring 28 is a spring mechanism according to the present invention, and the spring 29 is a flex spline 14b-, '1i3oi harmonic drive 14 of the harmonic drive 14.
, the mass 31 corresponds to the first arm 10, and the vibration source 32 corresponds to the torque unevenness of the harmonic drive 14. As described above, in the industrial robot according to the present invention, even if vibration occurs in the harmonic drive, there is no vibration before or after the harmonic drive. Providing the elastic body has the excellent effect of suppressing arm vibration.

FIG. 8 shows the timing belt portion of the second embodiment of the present invention, where 33 is a motor output shaft, 34 is a timing boot IJ attached to the motor output shaft 33, 35 is a harmonic drive input shaft, and 36 is a timing belt part of a second embodiment of the present invention. A timing pulley attached to the harmonic drive 35, 37 a timing belt, 38 swingable around a fulcrum, <-139 a timing pulley rotatably mounted at the tip of the lever 38, 4o , the timing pulley 39 is a spring provided to bias the timing belt 37 from the inside.

It is needless to say that the second embodiment described above has the same excellent effects as the first embodiment.

Effects of the Invention As described above, the present invention provides a tension reinforcing mechanism configured using elastic bodies on both sides of the timing belt, thereby making it possible to use another elastic body in addition to the flex spline of the Moninoku drive. It has the excellent feature of absorbing vibrations generated by harmonic drive, and its practical effects are unique.

[Brief explanation of the drawing]

Fig. 1 is a front view of a conventional industrial robot, Fig. 2 is a plan view of a harmonic drive, Fig. 3 is a longitudinal cross-sectional view of the harmonic drive, and Fig. 4 is an industrial robot according to a first embodiment of the present invention. Front view, FIG. 6 is an enlarged plan view of the same, FIG. 6 is an enlarged longitudinal sectional view of the same,
FIG. 7 is a schematic vibration diagram, and FIG. 8 is an enlarged plan view of a second embodiment of the present invention. 10...First arm, 11...Second arm, 12...Motor, 13...Motor,
14... Gnomonic drive, 14a...
...Circular spline, 14b...Flex spline, 14C...Web generator, 15...No1-moninoku drive, 16
...Timing pulley, 17...Timing pulley, 18.../S-Monisoku drive input shaft, 19...Timing belt, 20...
Bearing, 21...Bracket, 22...
... Bracket, 23 ... Robot base, 24
・・・・・・Bearing, 26・・・・Lever, 26・
...Bearing, 27...Flip, 28...
...Spring, 29...Spring, 3o...
Mass, 31...Mass, 32...Vibration source, 33...Motor output shaft, 34...Timing pulley, 36...No 1-Monisoku drive input shaft, 36... Timing boot IJ, 3
7...Timing belt, 38...Reno<
-539... Timing pulley, 40...
・Spring. Name of agent: Patent attorney Toshio Nakao (1st person)
Figure 2 Figure 3 Figure 4 O Figure 5 Figure 6 Figure 7 - Figure 8

Claims (3)

[Claims] (1) a rotary actuator, a differential reducer, a pulley attached to the shaft end of the rotary actuator, a pulley attached to the input shaft of the differential reducer;
An industrial robot having joints consisting of a belt hung on two pulleys, and two tension reinforcement mechanisms provided on both sides of the belt to increase the tension of the belt using elastic bodies. (2) The belt is a toothed belt, and the two tension increasing mechanisms include a lever that is swingable about a fulcrum, a roller that is rotatably provided at the tip of the lever, and a roller that is provided with a toothed belt. The industrial Kawaguchi bot according to claim 1, comprising a spring provided so as to be biased from the outside of the attached belt. (3) The belt is not a toothed belt, and the two tension reinforcing mechanisms include a lever that is swingable about a fulcrum, a toothed belt that is rotatably provided at the tip of the lever, and 2. The industrial robot according to claim 1, wherein the toothed pulley comprises a spring provided to be biased from inside the toothed belt.