JPS63180490A - Arm for 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 [Industrial Application Field] The present invention is used in industrial robots and relates to improvement of robot arms.

[Conventional technology]

In conventional industrial robots, in order to give a certain positional movement to the wrist, the arm that supports the wrist is made to perform the desired movement. The pipes are made of lightweight metal.

[Problem that the invention seeks to solve]

In conventional industrial robot arms, in order to achieve weight reduction while maintaining the required bending rigidity, the wall thickness of the pipe cannot be made very thin, and even if lightweight metal materials are used. In the end, it turned out to be a fairly thick pipe. Reducing the wall thickness to reduce the weight of the arm pipe also increases the transmission of vibrations generated during high-speed work.

[Means and effects for solving the problems] The present invention provides a second arm that swings the wrist portion, for example, in order to reduce the weight and give rigidity to the second arm, and to suppress resonance vibration of the arm.
As shown in FIG. 1B, a pipe 2 made of an aluminum alloy material is filled with vinyl chloride foam or urethane foam 21, so that the arm itself has a laminated solid cylindrical structure.

Since the arm has a solid structure, the bending rigidity, especially the buckling strength, is increased, so the pipe can be made thinner, and the porous filler absorbs resonance vibrations.

〔Example〕

As shown in FIGS. 2 and 3, the first arm 1 is connected to the trunk 1o via the first joint J, and the second arm 2 is connected to the first arm L via the second joint J2. Extending forward, the second
A wrist part 3 is connected to the tip of the arm 2 via a wrist joint J3, and an end effector is attached to the wrist end 4.
r) to create an articulated robot.

Then, as the second arm 2, as shown in FIGS. 1A and 1B, a thin-walled pipe made of aluminum alloy material is prepared,
A polyvinyl chloride solution mixed with a foaming agent was poured into the pipe, and then heated and foamed to form an aluminum alloy pipe into a solid structure filled with PVC foam.

In the obtained robot, the second arm 2 is connected to the trunk 10.
In addition to the rotation of the first arm 1 and the back-and-forth rotation of the first arm 1, the second arm itself also moves up and down, swinging the wrist 3 to an appropriate position in the vertical and horizontal directions. The resonant vibration of the second arm, which occurs at times, could be suitably absorbed by the polyvinyl chloride foam material inside the arm structure.

Also, since the buckling strength of the second arm is improved by filling it with polyvinyl chloride foam material, the wall thickness of the outer pipe material 2 can be made thinner, and as a result, the entire arm structure is lighter than the conventional pipe! [Despite the solidification, it was possible to provide sufficient bending rigidity, and to reduce the transmission of resonance vibration, which was a factor that inhibited work speed and work accuracy.

Note that the same effect was achieved even when CFRP (carbon fiber reinforced plastic) or GFRP (glass fiber reinforced plastic) was used instead of aluminum alloy as the pipe material on the outside of the second arm.

Furthermore, the same effect was achieved even when polyurethane foam was used instead of polyvinyl chloride foam as a filler.

However, when filled with lightweight solid plastics,
Although a reduction in weight and an increase in buckling strength were observed, the effect of reducing vibration transmission was not achieved.

〔Effect of the invention〕

Since the second arm that performs high-speed swinging motion is a solid structure made of a rigid pipe and a lightweight porous filler, the porous material absorbs and reduces vibration transmission. Further, due to the solid structure, the wall thickness of the outer pipe can be made thinner than that of a conventional pipe in order to improve buckling strength, and the second arm as a whole can be made lighter than the conventional one.

Since the second arm can be made lighter and vibration transmission can be reduced, highly accurate work can be accomplished faster.

[Brief explanation of the drawing]

FIG. 1A is a partial vertical cross-sectional view of the second arm embodying the present invention, and is a cross-sectional view taken along the line A--A in FIG. 2. FIG. 1B is a sectional view taken along the line B--B in FIG. 2. FIG. 2 is an overall schematic side view of an industrial robot to which the arm of the present invention is applied. FIG. 3 is an overall schematic front view of an industrial robot to which the arm of the present invention is applied. 1...First arm, 2...Second arm pipe,
3...Wrist part, 4...Wrist end part, 21.
...Porous filler.

Claims (1)

[Claims] 1. A lightweight porous material (21) for imparting rigidity in a pipe (2) made of a lightweight rigid material such as an Al alloy or CFRP.
An industrial robot arm made of a solid structure filled with 2. The arm according to claim 1, wherein the lightweight porous material (21) is a synthetic resin foam.