JPH0343037B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a balancing device for a swinging arm of an industrial robot.

Conventionally, in industrial robots, a balance device using a coil spring has been used to suppress the influence of the moment due to the load (work + wrist + arm weight) applied to the base attachment part of the swinging arm. Coil springs were installed coaxially with the rotation axis of the robot arm, or at locations where load moments were applied.

However, if the coil spring is installed coaxially with the rotation axis of the arm, the structure becomes complicated.
In addition, coil springs designed to handle large load moments could not be used due to limitations in installation space, and smaller coil springs had to be used, which caused problems such as insufficient balance. Further, even in the case of a configuration in which a coil spring is installed at a position where a load moment is applied, there is a problem that the device becomes large because the coil spring is a relatively large component.

This invention was made in view of these conventional problems, and provides a balance device for industrial robots that has a structure in which the load moment is supported by leaf springs, has a simple structure, and is easy to adjust the spring force. This is what we provide.

This invention will be explained in detail below along with embodiments shown in the drawings. FIGS. 1 and 2 show an embodiment of the present invention. The robot arm 1 includes an upper arm 3, a forearm 5 that can swing back and forth relative to the upper arm, and a wrist 7 at the tip of the forearm 5. It is supported so that it can swing back and forth. The swing base 9 is supported so as to be horizontally rotatable relative to a fixed base 13 of the robot.

The upper arm 3 is driven by an upper arm drive motor 17 supported by a bracket 15 and swings.
Further, the forearm 5 is driven by a forearm drive motor 19 and swings, and in combination with the rotational movement of the swing base 9, the entire arm 1 is bent in a desired direction, realizing movement similar to a human hand. be.

In this robot arm 1, leaf springs 21 and 23 are attached to the front and back positions of the upper arm 3 on the rotating base 9, respectively. Rollers 25 and 27 are attached to the upper ends of each leaf spring 21 and 23, and blocks 29 and 3 are attached to the front and rear of the upper arm 3, respectively.
It is designed so that it can come into contact with 1. The blocks 29, 31 are connected to adjustment screws 33, 35, for example, as shown in detail in FIG.
35, it can be slightly slid up and down, and the balance force by the leaf springs 21 and 23 can be adjusted. Also, each block 29, 3
1 has a concave lower surface and is arranged so that the rollers 25, 27 do not come off when they come into contact with each other. A stopper 37 provided on the bearing portion 11,
Reference numeral 39 is for preventing the leaf springs 21 and 23 from falling too far.

The balance of the forearm 5 is also achieved by the leaf spring 41. One end of the leaf spring 41 is fixed to the upper front surface of the upper arm 3, and the upper end comes into contact with a block 43 of the forearm 5. A roller 45 is also provided at the upper end of the leaf spring 41, and the balance of the block 43 can also be adjusted using an adjusting screw 47.

The operation of the balance device for an industrial robot having the above configuration will be explained next. The upper arm 3 swings back and forth with respect to the swing base 9 by the motor 17. Now, considering the state in which the arm 3 swings forward as shown in FIG. 1, this movement causes the roller 2 of the front leaf spring 21 to move.
5 comes into contact with the block 29 and is pressed and bent, and the spring force at this time supports and balances the load moment of the entire robot arm 1. For this reason, the moment of the entire robot arm 1 is not applied to the motor 17 and its servo system, and it is only necessary to provide the motor 17 and its servo system with the ability to move the amount that is insufficient by the spring force of the leaf spring 21.

During this forward swing, the rear leaf spring 23 is supported by the stopper 39, and the roller 27 is released from the block 31.

Conversely, when the upper arm 3 swings backward, the leaf spring 23 on the rear side acts to provide balance.

When the forearm 5 swings forward with respect to the upper arm 3, the leaf spring 41 acts, and the roller 45 contacts the block 43 to push and bend it, and the spring force at that time balances the load moment on the upper arm 5. . 3 and 4 show other embodiments. In this embodiment, slide guides 49 and 51 are installed vertically at the front and back of the upper arm 3, and the leaf springs 2
The sliders 53 and 55 provided at the upper ends of the slide guides 1 and 23 are fitted into the slide guides 49 and 51, respectively.

In this embodiment, as the upper arm 3 swings, the sliders 53, 55 of the front and rear leaf springs 21, 25 slide up and down the slide guides 49, 51, and the sliders 53, 55 move from the front and back to the upper arm at appropriate positions. 3
It supports the moment of According to this embodiment, the stopper 37 of the leaf springs 21, 23 as in the embodiment shown in FIGS. 1 and 2,
39 is no longer necessary, and the leaf spring 2 can be removed from both the front and rear.
1 and 23, the elastic force of each leaf spring can be reduced even if it is small.

FIG. 5 and FIG. 6 are still other embodiments,
Leaf springs 5 are attached to the pivot base 9 on the left and right sides of the upper arm 3.
7, 59, and the rollers 61,
Guide blocks 65 and 67 with 63 provided on the upper arm 3
It has a configuration in which it is freely inserted into the gap 69, 71 of the vehicle.

In this embodiment, both leaf springs 57 and 59 work together to support and balance the load moment when the upper arm 3 swings in either the forward or backward directions.

It is also possible to use slide guides shown in FIGS. 3 and 4 in place of the guide blocks 65 and 67.

As can be understood from the above description of the embodiments, the present invention basically provides balance mounting of an industrial robot in which the upper arm 3 is provided on the base 9 so as to be swingable in the front and back direction, and the upper arm 3 is attached to the base 9.
The lower ends of an appropriate number of leaf springs provided on the front, rear, or side sides of the pivot joint are fixed to the base 9, and the upper ends of the leaf springs are configured as free ends. , when the upper arm 3 swings in the front-back direction, the upper arm 3
The leaf spring is provided so as to be movable in the longitudinal direction of the upper arm 3 in order to return it to a vertical state, and the leaf spring is provided so as to be flexible following the swinging movement of the upper arm 3.

As is clear from the above structure, the present invention relates to a balance device for an industrial robot using a leaf spring, in which the lower end of the leaf spring is fixed to the base 9, and the upper end is a free end. It is secured to the upper arm 3 so as to be movable in the longitudinal direction. Therefore, according to the present invention, there is no need to curve the leaf spring around a position that coincides with the axis of the pivot point of the upper arm 3 relative to the base 9, and the degree of freedom in providing the leaf spring is large, and the leaf spring can be easily formed. It can be adopted in the following manner, and the configuration is simpler.

[Brief explanation of drawings]

Fig. 1 is a side view of one embodiment of the present invention, Fig. 2 is a front view of the same leaf spring section, Fig. 3 is a side view of another embodiment, and Fig. 4 is a front view of the same leaf spring part. FIG. 5 is a side view of still another embodiment, and FIG. 6 is a front view of the same. 1... Robot arm, 3... Upper arm, 9... Swivel base, 21, 23... Leaf spring, 25, 27... Roller, 29, 31... Block, 49, 51...
Slide guide, 53, 55...Slider, 5
7, 59...Plate spring, 61, 63...Roller, 6
5, 67... Guide block, 69, 71... Gap.

Claims (1)

[Claims] 1. A balance device for an industrial robot comprising an upper arm 3 mounted on a base 9 so as to be swingable in the front and rear directions,
The lower end portions of an appropriate number of leaf springs provided at the front, rear, or side sides of the pivot point of the upper arm 3 to the base 9 are fixed to the base 9, and the upper ends of the leaf springs are configured as free ends. The upper arm 3 is configured such that the free end of the leaf spring is movable in the longitudinal direction of the upper arm 3 in order to return the upper arm 3 to a vertical state when the upper arm 3 swings in the front-back direction.
A balance device for an industrial robot, characterized in that the plate spring is provided so as to be able to bend freely following the swinging movement of the upper arm 3.