JPS5851087A - Driving device for arm of 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 The present invention provides an industrial robot having arms that rotate around respective main axes, in which a reduction gear and an electromagnetic The present invention relates to an arm driving device that can actuate an electromagnetic brake to stop a swinging motion of an arm in a short time by interposing a brake, and can maintain a braked state when stopped.

Conventionally, in this type of robot, the arm axis is driven directly by a drive motor or rotationally driven via a reduction gear, so the holding force at the stop position of the arm is equal to the holding force of the drive motor. There is a limit to this holding force, and positional deviations occur when external forces are applied, and the reducer itself has elasticity in the rotational direction, so the positioning accuracy is not good. In such robots, when stopping the movement of the arm, the drive motor is braked using a power generation brake, or a reverse voltage is applied to the drive motor, but in the former case, the rotation speed is low. In the latter case, the braking effect is small, and in the latter case, the control becomes complicated, and near the stopping point, it is not possible to apply a large voltage from the viewpoint of control stability, so the expected braking effect cannot be obtained. It takes longer to stop and the braking distance. Therefore, in the case of an emergency stop, it becomes impossible to stop in a short time and over a short distance, and there is a risk of collision with an obstacle.Also, in order to increase the holding force of the drive motor, the control gain is There were drawbacks such as hunting occurring when raised and positioning impossible. However, the fact that the above-mentioned holding force is weak means that when an external force is applied, the amount by which the arm is displaced is large in proportion to this, and the I flexibility (compliance) of the arm is large.

When a robot with a flexible arm inserts a pin in this way, even if the pin position is slightly off, when the pin is pushed in, the arm passively displaces along with the pin along the chamfer of the insertion hole. This is convenient because the pin can be inserted without being twisted. However, the hole drilling method using 1.D U71/ had a drawback in that the position of the hole holder would shift at the beginning, making the work completely impossible.

The present invention was made in order to eliminate the above-mentioned drawbacks, and by interposing a speed reducer and an electromagnetic brake in the rotation transmission path between the main shaft of the arm of the robot and the drive motor, the turning operation of the arm is improved. When stopping the arm, the electromagnetic brake is activated to stop the arm in a short time, and while the arm is turning, if the arm's turning speed at that point is higher than the target speed, the brake is applied to stabilize the control. It was devised for the purpose of making it possible to hold the arm with the electromagnetic V-key applied while it is stopped, increasing the arm's ability to hold the position against external forces, and achieving high positioning accuracy. 〇＠1 diagram and i! In Figure 2, +141 is the first principal axis (
1) is a first arm rotatably supported by the arm.

At the base of this first arm [+41], on the center line of the first E-axis (11), a cylindrical motor pace circle with 03 formed inside is attached, and at the upper end of this motor pace Qll. The drive motor 01 is attached. This drive motor (IG) has a built-in rotation detector (not shown) and is configured to feed back a signal corresponding to the rotation angle to a control device (not shown). .

A speed reducer +s is attached to the upper collar part 1z of the motor pace a0.
) Attach the nose flange (71) and attach the lower flange a3.
The drive shaft (9) of the drive motor fIG to which the case flange (41) of the electromagnetic brake (31 is attached) is connected to the input shaft (8) of the reducer (6) by a shaft coupling or the like. The output shaft 15) of the machine (6) is the electromagnetic brake (3)
It is connected to the upper end of a brake shaft (2) that extends through the center of the brake shaft.

This brake shaft (2) is configured to be non-rotatable or rotatable by energizing or de-energizing the electromagnetic brake (31).The lower end of this brake shaft (2) is connected to the upper end of the @l main shaft 11. The arm driving device for the first joint is configured by being fixed to the arm.

On the other hand, as the arm drive device for the second joint, the +11!1
Similar to the joint, there is a second arm at the tip of the first arm +14.
The second spindle α9 with the arm
1G is installed. A drive motor 151, a reduction gear α9, and an electromagnetic brake 11 are attached to this motor pace 1G. The drive shaft of the drive motor is connected to the second main shaft αS via a speed reducer and an electromagnetic brake sling to constitute an arm drive device for the second joint. Furthermore,
It is also possible to construct a multi-joint industrial robot by adding an arm drive device for the third joint and above.

In this embodiment, a drill unit is attached to the tip of the second arm circle as a work unit CID, and this is used by replacing it depending on the type of work.

To explain the operation of the industrial arm drive device of the present invention configured as described above, the drive motor aI starts rotating in response to a command signal from a control device (not shown). This rotating shaft rotates the input shaft (8) of the reducer 16), and the reduced output shaft (5) attempts to rotate the brake shaft (2) of the electromagnetic brake (3). However, this brake shaft (2) is fixed to the first main shaft (1) and cannot rotate. Therefore, as a reaction force, the drive motor αl
Rotation is transmitted to the motor base + Ill.
Therefore, the rotation angle of the first arm α4 is fed back by a rotation detector (not shown) and is compared with a command signal to generate a deviation signal. When it runs out, the drive motor αl stops. In other words, the first arm is stopped at a position corresponding to the command signal and is positioned in one position.

The speed at each point (position) from when the first arm 0@ starts moving until it stops is programmed in advance in a control device (not shown). If the target speed is exceeded, the electromagnetic brake (3) is activated to apply braking, and if the target speed is lower than the target speed, the drive motor is activated.

Such operations are repeated, and the @l arm (audience) rotates according to the program, and when it reaches the target position, it stops and is positioned.

If an external force acts on the first arm I, which is positioned at 5 positions, for some reason, the drive motor 03, rotation detector (not shown), etc. are rotated in that direction, and a deviation signal is generated. The drive motor rotates so as to always correct this and return it, and stops when the deviation signal becomes zero. At this time, the first arm [+41] pivots and displaces approximately in proportion to the external force.

This amount of displacement varies depending on the holding force of the drive meter.
Further, it varies depending on the rigidity in the rotational direction of the rotating part of the reducer (61). In this way, the first arm +141 has a large flexibility (compliance) in the turning direction.

After the first gear 141 is positioned as described above, the electromagnetic brake 13) is energized and the brake shaft (2
) by fixing the rotation of the first arm I to WS
l Fix to the main shaft (1). It's hot at this time, yo II
The IGI arm 14 has high rigidity against external forces.

In other words, the compliance is in a small state.O Next, to explain the operation of the arm drive device of the tJIc2 joint, the second arm (■) rotates around the second main axis a9, relative to the 1!1arf1I41. do. When the electromagnetic pulley Qe is activated, the second arm (2) is fixed to the 1gl arm 114+. Drive motor a
The operations from when 9 starts rotating until it stops, is positioned, and the electromagnetic brake Qe completes operation are exactly the same as the operations of the arm drive device of the first joint. Normally 1g summer is 5041. The t1g2 arms (to) operate almost simultaneously.

In the above state, the work unit [cn] looks at the tip of the second arm ■, for example drilling a hole, and when one work is completed, each arm turns to the next work position in response to a command signal. Repeat the action. Depending on the type of work, the bottle can be easily inserted by making the arm flexible and inserting the pin without operating the electromagnetic brake, as described above.

As described above, the present invention includes a reduction gear and an electromagnetic pulley in the rotation transmission path between the main shaft of each arm and the motor that drives it.
Since the arm is configured to be rotated and positioned using a key, when stopping the arm operation, the electromagnetic brake is activated to stop the arm in a short time and over a short distance. I can do it. Therefore, not only does work efficiency improve, but also it is possible to stop quickly in the event of an abnormal or emergency stop, which prevents collisions with obstacles. Also, when handling workpieces or work units with large inertia. However, by activating the electromagnetic brake, it is possible to stop quickly, which reduces the chance of overshooting from the target position, stabilizes control, and prevents hunting, allowing highly accurate positioning. Furthermore, by using different electromagnetic brakes depending on the type of work and by changing the degree of flexibility of the arm, it is possible to perform work such as inserting a bottle or drilling a hole, making it possible to handle type A work, etc. effect can be obtained.

@, In the configuration of the arm drive device of the above embodiment, the drive motor and the reducer are separate bodies, but instead of these, the drive motor and the reducer may be integrated into one. , this also simplifies the structure. In addition, the reducer and the electromagnetic brake may be arranged interchangeably. In this configuration, when the electromagnetic brake is activated, the rotation of the drive shaft of the drive motor, the brake shaft, and the input shaft of the reducer is based on the motor base. However, since rotating parts such as gears and transmission shafts in the reducer have elasticity in the direction of rotation, the arm has corresponding elasticity in the direction of rotation with respect to the main shaft.

Greater flexibility. On the other hand, electromagnetic brakes.

Even if it is a high-speed brake, it exerts a large braking effect in inverse proportion to the reduction ratio when the arm on the output shaft side turns.

[Brief explanation of the drawing]

FIG. 1 is a plan view of an embodiment in which a work unit is attached to an industrial robot soto equipped with an arm drive device of the present invention, W
Figure IJ2 is a sectional front view of the main part of Figure 1. (1) is the first main shaft, and (2) is the brake shaft. (3) C electromagnetic brake, (4) case flange. (5) is the output shaft, and (6) is the reducer. (7) is the case flange, and (8) is the input shaft. (9) is the drive shaft, [11 is the drive motor, 1
11) is the motor base, @, α3 part. 041 is the first arm, and 051 is the drive motor. The shout is the motor base, α9 is the reduction gear. a second is electromagnetic brake, a- is If! 2 main axes.

Claims (1)

[Claims] In an industrial robot having arms that rotate around respective main shafts, a drive motor is provided on the center line of each main shaft, and a reducer and an electromagnetic brake roller are fixed to the arms between the drive shaft of the drive motor and the main shaft tonnage. What is claimed is: 1. An arm drive device for an industrial robot, characterized in that the drive shaft is arranged and attached in series to each of the motor paces, and the main shaft is connected to the drive shaft via the respective shafts of a reducer and an electromagnetic brake.