JPH0847885A - Balancer device for industrial robot - Google Patents

Abstract

PURPOSE:To provide a balancer device for a multi-joint industrial robot by making the part around an arm of the robot compact so that the operating range of the arm is not limited. CONSTITUTION:In a balancer of an industrial robot, is composed of a wheel 6 associated with a first arm 10 provided to a joint shaft 7a for tilting the first arm 10 and having a groove which receives therein a wire 4 which is secured at its one end to the wheel 6 and which wound with the intermediate part of the wire 4, and a guide 20 for the wire 4, and an unbalance moment compensating mechanism having one end connected to the leading end of the wire and the other end provided a frame on which the first arm 10 is rotatably supported. Multistage weights 3a...3f and a resilient member 21 are used for the balance moment compensating mechanism.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a balancer device for an articulated industrial robot. When the arm of the articulated industrial robot is tilted, the moment changes due to the weight of the arm and the work, so a balancer is generally provided.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 3 (a), a first arm 10 rotatably provided on a joint shaft 7a provided on a frame 1 and a joint shaft 7b at the tip of the first arm 10 are provided. The second arm 11 rotatably provided, and the spring cylinder 15 rotatably provided between the shaft 14 and the joint shaft 7b provided on the frame 1 so as to be eccentric to the joint shaft 7a on the side of the first arm 10, As shown in FIG. 2B, from the state of FIG.
When the cylinder 15 is tilted to the above state, the cylinder 15 extends and the change of the moment is absorbed by the displacement of the spring installed therein.

[0003]

However, the conventional technique has the following problems. (1) Since there is a balancer on the side of the robot arm,
It lacks compactness and easily interferes with the devices and work around the robot. (2) The tilt range of the first arm is limited due to the limitation of the stroke of the cylinder. Therefore, an object of the present invention is to provide a balancer device in which the vicinity of an arm of a robot is made compact and the tilting range of the arm is not limited.

[0004]

In order to solve the above problems, the present invention relates to a balancer device for an industrial robot, in which a wire that is interlocked with a first arm provided on a joint shaft for tilting the first arm is wound. A wheel having a groove, a wire having one end fixed to the wheel and a wire wound around the groove of the wheel, a guide for aligning the wire with the axis of the joint shaft, one end at the tip of the wire, and the other end at the other end. A balancer device is constituted by a variable load fixed to a frame that rotatably supports the first arm. A multi-stage weight or elastic body is used as the variable load.

[0005]

With the above-mentioned means, a counter-moment is generated by the variable load in response to the tilting of the arm, and the moment change of the arm is compensated.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. 1A is a side sectional view, and FIG. 1B is a front sectional view. At the bottom of the C-shaped frame 1 that opens upward, a holder 2 is provided on the inner diameter side, which is provided with a multistage shelf for accommodating disk-shaped weights 3a, 3b, 3c, ... As an unbalanced moment compensation mechanism. It is fixed. The installation interval between the lowermost weight and the uppermost weight is associated with the outer diameter of the wheel 6 described later and corresponds to the tilting range of the first arm 10. At the center of the weights 3a, 3b, 3c ... 3f,
The wire 4 is provided with a hole through which it can move freely, and a cushioning material 30 is attached to the upper surface thereof. A stopper 5 is provided at one end of the wire 4 so that when the arm 10 stands upright, it comes into contact with the bottom of the lowermost weight 3a.
The wire 4 is wound around a wheel 6 having a groove at the center, and the other end is fixed to the wheel 6. Between the uppermost weight 3f and the lower surface of the wheel 6, the wire 4 is guided from both sides by rollers to form a guide 20.
The centers of a, 3b, 3c, ... 3f are made to coincide with the axis of the joint shaft 7a. The axis of the wheel 6 is fixed to a joint shaft 7a provided in the opening of the frame 1, and is rotated by a motor 8 and a speed reducer 9 in response to tilting of the first arm 10. When the first arm 10 is tilted from the upright state by the motor 8 and the speed reducer 9, the wheel 6 rotates, winds the wire 4, and lifts the lowermost weight 3a that abuts the stopper 5.
Further, when the first arm 10 is tilted, the weight 3a
.., the weights 3b, 3c, ... Are sequentially stacked, the weight is gradually increased, the anti-moment is gradually changed, and the unbalanced moment is compensated stepwise.

FIG. 2 shows another embodiment. One end of a cylindrical or columnar elastic body 21 such as a coil spring, rubber, or plastics is fixed to the bottom surface of the frame 1, and the other end of the elastic body 21 is fixed to one end of the wire 4. The other end of the wire 4 is fixed to the wheel 6 as in the embodiment. Here, the stroke of the elastic body 21 is associated with the outer diameter of the wheel 6 and corresponds to the tilting range of the first arm 10. In this case, when the first arm 10 is tilted from the upright state, the elastic body 21 extends to continuously generate an anti-moment and continuously compensate the unbalanced moment.
The entire wire 4 may be the elastic body 21.

[0008]

As described above, the present invention has the following effects. (1) Since the anti-moment generating mechanism is housed in the frame, the area around the robot arm can be made compact and interference with surrounding objects (equipment, equipment, work, etc.) during robot work is reduced, and the work range is correspondingly reduced. Can be taken large. (2) Since the stroke of the variable load generating mechanism can be freely set based on the relationship between the outer diameter of the wheel and the tilting range of the first arm, the tilting range of the robot arm is not limited.

[Brief description of drawings]

FIG. 1A is a side sectional view showing an embodiment of the present invention,
(B) is a front sectional view.

FIG. 2 is a partial side sectional view showing another embodiment of the present invention.

3A and 3B are side views showing a conventional example.

[Explanation of reference numerals] 1 frame 2 holder 3a, 3b, 3c ... 3f weight 4 wire 5 stopper 6 wheel 7a, 7b joint shaft 8 motor 9 reducer 10 first arm 11 second arm 14 shaft 15 spring cylinder 20 guide 21 elasticity Body 30 cushioning material

Claims (3)

[Claims] 1. In a balancer device for an industrial robot, a wheel having a groove, which is interlocked with a first arm provided on a joint shaft for tilting the first arm, and one end of which is fixed to the wheel, and the groove is partway along the groove. A wound wire, a guide for maintaining the movement of the wire at a predetermined position, and an unbalanced / moment compensating mechanism provided at one end of the wire at the tip of the wire and at the other end of the frame for pivotally supporting the first arm A balancer device for an industrial robot, which is characterized in that 2. The balancer device for an industrial robot according to claim 1, wherein the variable load is a multi-stage weight. 3. The variable load is an elastic body.
Balancer device for the described industrial robot.