JPH01257592A - Wrist mechanism of industrial robot - Google Patents

Abstract

PURPOSE:To prevent torsion of a wire hose when the operation of a wrist is deflected and to facilitate control for the supply of material from a wire hose to a working tool by inserting a wire hose connected to the working tool in the interior of a hollow lower arm. CONSTITUTION:A wire hose 6 is inserted in a hollow portion occupying the center in a lower arm 3 formed by a hollow cylinder, and a working tool 5 symmetrical about the shaft center line 0-0 is connected to the forward end of the wire hose 6. The wire hose 6 and the working tool 5 are supported by a bearing B2 at the base end of the lower arm 3 and a bearing B1 at a support portion of a fitting flange 50 in such a manner as to freely rotate. Accordingly, even if torsional moment is produced in the wire hose 6 due to wrist operation such as gamma-axis wrist rotation, beta-axis wrist oscillation and so on caused by control rotation of the lower arm 3 and the control rotation of an inner cylinder 7, the wire hose 6 is kept from showing torsional form by slip rotation of the respective bearings B1, B2. Accordingly, the supply of material from the wire hose 6 to the working tool 5 can be easily controlled.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a wrist mechanism for an industrial robot used for tasks such as arc welding, spot welding, sealing, water cutting, and handling, and is capable of handling work tools. It is rotatably supported on the mounting flange to prevent twisting from being applied to the hose or cable connected to the work tool.

Conventionally, in a five-axis articulated robot, a work tool is fixed to a mounting flange for control, and wires, hoses, etc. for the work tool are arranged along the outer periphery of the robot.

Furthermore, some six-axis articulated robots have a hollow lower arm and have a wire hose, etc. placed inside.

[Problem to be solved by the invention]

In conventional robots with wires or hoses attached to the outer circumference of the arm, the wires or hoses may interfere with or get caught in the wrist due to wrist movements during work, or strong forces such as twisting or pulling may be applied. This caused problems such as wires breaking and hoses collapsing.

In addition, in the case of a 6-axis articulated robot, the rotation of the work tool itself is also program-controlled, so if the wire hose is enclosed inside the lower arm, the wire hose can be twisted by the movement of the wrist. , pulling action is unavoidable, and there is a danger of eventually breaking the wire or crushing the hose.As a measure against twisting, the wire and hose were placed sufficiently loose in the lower arm, but the repeated twisting of the stationary type The action was causing damage to the wire hose.

[Means and actions for solving the problem] For example, the first
As shown in the figure (^), a wire hose 6 is inserted into the hollow part occupying the center of the lower arm 3, and a work tool 5 symmetrical to the axis 0-0 is connected to the tip of the wire hose. The wire hose 6 and the working tool are rotatably supported by the bearing B2 at the base end of the arm and the bearing B at the support portion of the mounting flange 50.

Since the wire hose 6 is rotatably supported at the base end of the lower arm and the tip of the wrist, the controlled rotation of the lower arm and the controlled rotation of the inner cylinder 7 allow wrist movements such as T-axis manual rotation and β-axis wrist swing. Even if a twisting moment is generated in the wire hose 6 as a result of this, the wire hose 6 will not take on a twisted configuration due to the slip rotation of each bearing B+, Bz.

Moreover, since the work tool 5 is symmetrical about the axis 0-0, even if it rotates around the 0-0 axis with respect to the wrist tip 40, no problem will arise in the work.

〔Example〕

FIG. 2 is an overall perspective view of a five-axis articulated robot for arc welding according to the present invention, and FIG. 3 is a schematic diagram of its axis configuration.

As is clear from the figure, the robot has a rotating shaft 1 that rotates on the θ axis via a rotating table B on a base B, and an upper arm 2 that rotates on the W axis via a joint J at the upper end of the rotating table R1. , the lower arm 3 protrudes forward through a joint J at the upper end of the upper arm 2 so as to rotate on the U axis, and the lower arm 3 rotates the wrist on the T axis by means of the rotating part Rt at the base, and joints J at the tip, It is configured such that the work tool 5 can be swung by the β-axis wrist.

The present invention was applied to the wrist mechanism in the robot shown in FIGS. 2 and 3 as shown below.

[Example 1] As shown in Fig. 1 (^), an inner cylinder 7 is disposed inside the lower arm 3 made of a hollow cylinder, and the wrist 4 is swung on the β axis by a bearing B at the tip of the lower arm 3. In addition to connecting like this,
A wire is placed on the axis 0-0 from the inside of the inner cylinder 7 to the inside of the wrist 4.
The hose 6 is inserted through it and is freely rotatably supported by the bearing B8 at the base end and the bearing B at the tip end, and the wire
Attach the work tool 5 symmetrical to the 0-0 axis to the tip of the hose 6, and attach the mounting flange 50 of the work tool 5 to the wrist tip 40.
Supported for free rotation.

The lower arm 3 is rotationally driven from a wrist rotation motor M via a reduction gear, and the inner cylinder 7 is rotationally driven from a hand gesture motor M via a reduction gear. Inner cylinder 7
Bevel gear 8 with a wire hose loosely inserted into the center hole at the tip
engaged.

In the obtained wrist mechanism, the wrist 4 rotates on the γ axis and swings on the β axis by the rotation of the program-controlled motors M and M2, and freely deflects the work tool (welding torch) 5. , any twisting moment on the wire hose 6 caused by the movement of the wrist 4 is removed by sliding rotation by the bearings B2 and 81, and no residual twist occurs in the wire hose during any deflection of the wrist movement. There is no work tool 5, and the work tool 5 is 0.
Because of the symmetrical shape of the −0 axis, even if relative rotation with the wrist tip 40 (relative rotation that occurs to remove twisting of the wire hose) occurs due to wrist movement, no problem occurs in the work.

[Example 2] As shown in FIG. 1 (8), the hand swing motor M2 is placed inside the lower arm 3, and the hand swing motor M2 is connected to the hand bevel gear 9 from a small bevel gear placed on the side of the wire hose 6. The configuration was the same as in Example 1, except that the β-axis swinging motion of the wrist was controlled via the rotationally transmitted rear speed gear.

In the obtained hand mechanism, the backlash that occurred between the bevel gears ``and 9'' was favorably reduced by the reduction gear.The other effects were the same as in Example 1. .

[Example 3] As shown in FIG. 1(C), one bevel gear 9' of hand i4 is inclined at 45 degrees with respect to the axis 0-0, which is the wire/hose arrangement line, and one is set on the line O-0. The configuration was the same as in Example 1, except that the wrist 4 was rotated around the axis line XX intersecting with the line XX, and the wrist 4 was swung around the line XX along the β axis.

In the obtained reworking mechanism, the working tool 5 is
It was possible to control the posture by rotating around the .

In other respects, the same effects as in Example 1 were obtained.

It should be noted that the inclination angle of line XX with respect to line O-0 can be appropriately selected within the range of 0° to 90°.
It is self-evident for stones.

[Effects of the invention] As long as the work tool is of a type that does not cause trouble when the tip is attached to a surface even if it is rotated, the wire or hose can be easily attached without causing any twist to the wire or hose. The hose can be placed compactly inside the lower arm.

The wire hose can be placed in a straight line within the lower arm, and the wire hose does not twist even when the wrist is deflected.
Material supply from wire hoses to work tools can be easily controlled.

Since the wire hose is placed inside the lower arm, the workability and operability of the robot are improved.

[Brief explanation of the drawing]

(^), (81, and (C) in Fig. 1 are schematic sectional views of each embodiment of the present invention. Fig. 2 is an overall perspective view of a robot to which the present invention is applied; The figure is an explanatory diagram of the axis configuration. 1... Swivel axis, 2... Upper arm, 3... Lower arm, 4... Wrist, 5... Work tool,
6... Wire hose, 7... Inner cylinder,
8.8', 9.9'...Bevel gear, 40...Wrist tip, 50...Mounting flange.

Claims (1)

[Claims] 1. The lower arm (3) is made hollow, and a wire hose (6) connected to a working tool is inserted into the lower arm to prevent twisting of the wire hose caused by wrist movements. A wrist mechanism for an industrial robot, characterized in that removal is performed by free rotation of a hose (6). 2. The working tool (5) connected to the tip of the wire hose (6) is symmetrical to the axis (O-O), and the working tool can be freely rotated around the axis (O-O). 2. A wrist mechanism according to claim 1, supported on the wrist tip (40). 3. Place the wrist (4) with the working tool (5) rotatably supported on the tip (40) at the line (X-X) that intersects the line (O-O).
3. The wrist mechanism according to claim 2, wherein the wrist swings around the β axis.