JPH10217178A - Cable wiring device for robot - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent rubbing of a cable in a cable part near the base end of a robot arm. SOLUTION: A robot arm 4 is furnished at its tip with a wrist 6 capable of rotating around a longitudinal axis of the robot arm 4, and a cable 11 is connected with a wrist 6. With this wiring device, the cable 11 is spirally wound within the robot arm 4, wherein fasteners 131 and 132 stationary relative to the cable 11 are mounted on it at a spacing approx. equal to the specified winding pitch of the spiral and coupled together through a coupling member 141 longitudinal in the winding pitch direction, and the fastener 131 on the base end side of the robot arm 4 is coupled with the robot arm 4 in such a way as admitting movement in the circumferential direction relative to the robot arm 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cable wiring device connected to a wrist at the tip of a robot arm.

[0002]

2. Description of the Related Art Conventionally, in a robot provided with a wrist rotatable around the longitudinal axis of the robot arm at the tip of the robot arm, a cable connected to the wrist is spirally wound inside the robot arm. In addition to the above arrangement, a donut board-shaped wiring holding member which is positioned inside the robot arm on the distal end side and the base end side of the arm and is rotatable relative to the robot arm is provided. It is known that a cable is loosely inserted and a wire holding member on the distal end side is connected to a wrist via a connecting rod (see Japanese Utility Model Laid-Open No. 4-63386).

[0003] According to this, when the wrist is rotated, the wire holding member connected to the wrist via the connecting rod also rotates, so that the cable relatively moves with respect to the wire holding member on the tip side. Therefore, the cable between the wrist and the wire holding member on the distal end side is not locally bent.

[0004]

However, with such a structure, it is impossible to prevent the cable between the wiring holding member on the base end side and the cable from rubbing. Not only that, when the distal-side wiring holding member is connected to the wrist as in the above-described device, the displacement of the cable between the base-side wiring holding member and the cable when the wrist is rotated is reduced. As compared with the case where the wire holding member on the distal end side is not connected to the wrist portion, the wire holding member becomes larger, and rubbing at the portion near the base end of the cable is more likely to occur.

[0005] In the conventional apparatus, a protective tape having a small frictional resistance is wrapped around the outer periphery of the cable or a solid lubricant is applied to reduce the damage to the cable. It does not fundamentally solve the problem, and there are problems with durability and maintainability.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a cable wiring apparatus which does not cause rubbing of a wired cable.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a wiring device for a cable connected to a wrist rotatable around a longitudinal axis of a robot arm provided at the tip of the robot arm. Wherein a cable is spirally wound in a robot arm and disposed, wherein fixed fasteners are attached to the cable at intervals substantially equal to a predetermined spiral winding pitch, and these fasteners are attached to the cable. Are connected via a connecting member that is long in the winding pitch direction, and the fastener on the proximal end side of the robot arm is connected to the robot arm so as to allow movement in the circumferential direction with respect to the robot arm.

With this configuration, the pulling force received by the cable when the wrist rotates is transmitted not only to the portion near the distal end of the cable but also to the portion near the proximal end via the fastener and the connecting member. As a result, the tensile force applied to each portion of the cable becomes more uniform, and each portion moves by a corresponding amount, so that the cable can be prevented from being locally bent or pulled. And since a fastener is immovable with respect to a cable, it can prevent rubbing of a cable.

Further, the plurality of fasteners are connected to the robot arm via fasteners on the robot arm base end side. Therefore, even when the robot arm is rotated with the wrist at the distal end thereof facing downward, the cable does not lean toward the distal end of the robot arm, and the cable is supported within the distal end of the robot arm and the cable leans toward the distal end. The problem that the part is pulled locally does not occur.

If the connecting member is constituted by a member which can be elastically extended, even if the movement of the fastener on the base end side of the robot arm is restricted for some reason, the connecting member is extended and the cable is extended. Damage to creatures is reduced.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, reference numeral 1 denotes a guide member which is long in the horizontal direction, and has a robot main body 2 slidably supported by a guide rail 1a fixed to the guide member 1, and a guide. A motor 3 having a pinion 3a on an output shaft meshing with a rack 1b fixed to the member 1
The robot 3 is horizontally moved by the motor 3.

The robot body 2 has a vertically extending robot arm 4 having a rail 4a fixed to the robot arm 4.
A motor 5 having a pinion 5a on an output shaft meshing with a rack 4b fixed to the robot arm 4 is mounted on the robot main body 2, and is slidably supported in the vertical direction through the robot arm 4. The arm 2 is moved up and down.

A robot arm 4 has a wrist 6 at its tip, that is, at its lower end, which is rotatable around a V-axis which is a longitudinal axis of the arm 4. A shaft 7 connected to the wrist 6 is inserted into the robot arm 4, and a motor 8 connected to the shaft 7 is mounted on the base end, that is, the upper end of the robot arm 4. The part 6 is rotated around the V axis. On the wrist 6,
A joint 9 rotatable about a horizontal U-axis orthogonal to the V-axis is provided, and a motor 10 mounted on the wrist unit 6 rotates the joint 9 about the U-axis to attach the welding gun to the joint 9. Of the tool can be changed with two degrees of freedom of the V axis and the U axis.

A cable 11 for supplying power to the motor 10 and a control signal are connected to the wrist 6. The cable 11 is connected to the shaft 7 through the opening 7a at the tip of the shaft 7.
And is spirally wound and wired inside the robot arm 4 so as to surround the shaft 7 toward the upper end side of the robot arm 4. Note that the cable 11 is in the first position at a position immediately after being pulled out from the opening 7a.
It is fixed to the shaft 7 by the fixing device 12 ₁ and is fixed to the robot arm 4 and is led to the outside of the robot arm 4 by a second fastener 12 ₂ at the proximal end of the robot arm 4.

By simply winding the cable 11 in a spiral shape, even if the wrist 6 rotates and the lower end of the cable 11 is pulled, the pulling force is not transmitted to the portion near the upper end of the cable 11. Only the portion of the cable 11 near the wrist 6 is pulled.

[0016] Therefore, in this embodiment, the cable 11 wired to the helical fastener 13 ₁ to the winding pitch at equal intervals two upper and lower spiral, 13 ₂ mounted immovably, both fasteners 13 ₁ , together with the coupling 13 ₂ via the connecting member 14 ₁ of the long in the vertical direction a coil spring,
Linked to be movable in the circumferential direction to the robot arm 4 the fastener 13 _first upper via the connecting member 14 ₂ made of a coil spring.

[0017] In this way, the wrist portion 6 and the shaft 7 is rotated cable 11 is pulled, the fastener 13 ₂ on the lower side moves, which the upper fastener 13 ₁ by the connecting member 14 simultaneously ₁ Is pulled and moved, and the pulling force is transmitted to a portion near the upper end of the cable 11.
As a result, the pulling force is evenly transmitted to the entire cable 11, and each portion of the cable 11 moves by an amount corresponding to its position, so that the cable 11 is not locally bent or pulled. In addition, fastener 1
Since 3 ₁ and 13 ₂ are fixedly attached to the cable 11,
The cable 11 does not rub between the fasteners 13 ₁ and 13 ₂ . If there are three or more fasteners to be connected, each fastener is connected to an adjacent fastener in a daisy chain.

Further, connecting the upper fastener 13 _first member 14
By coupling to the robot arm 4 through _2, by fasteners 13 ₁ on the lower side is supported by the robot arm 4 through the upper fastener 13 _2, cable 11 is the lower end of the robot arm 4 Leaning is prevented. Therefore, the cable 11 is supported on the inner peripheral surface of the lower end portion of the robot arm 4, and when the wrist 6 is rotated, the cable 11
Can be prevented from being locally pulled at a portion near the lower end.

The connecting member is composed of a wire or a rigid bar, and each end of the wire is fixed or pivotally attached to each fastener, or each end of the bar is pivotally attached to each fastener. Alternatively, the fasteners may be connected. However, if the connecting member constituting the connecting member as in the above embodiment by a coil spring and elastically extensible, fastener 13 ₁ movement on the base end side of the robot arm 4 is restricted for some reason Also, the damage given to the cable by the extension of the connecting member is reduced.

In the above embodiment, the upper fastener 13
₁ was connected to the robot arm 4 by the connecting member 14 ₂ composed of a coil spring, as the upper fastener, for example, used as comprising a ring-shaped peripheral portion, the ring-shaped fastener in the robot arm The engagement may be freely rotatable in the circumferential direction.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a robot arm equipped with the device of the present invention.

FIG. 2 is a front view in which a part of a robot arm is cut away.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Guide member 2 Robot main body 4 Robot arm 6 Wrist part 7 Shaft 11 Cable 12 ₁ , 12 ₂ Fixture 13 ₁ , 13 ₂ Fastener 14 ₁ , 14 ₂ Connecting member

Claims (2)

[Claims] 1. A wiring device for a cable connected to a wrist rotatable around a longitudinal axis of a robot arm provided at a tip of the robot arm, wherein the cable is spirally wound inside the robot arm. In the arrangement, fixed fasteners are attached to the cable at intervals substantially equal to a predetermined spiral winding pitch, and these fasteners are connected via a connecting member that is long in the winding pitch direction. A cable wiring device for a robot, wherein a fastener on a base end side of the robot arm is connected to the robot arm so as to be allowed to move in a circumferential direction with respect to the robot arm. 2. The apparatus according to claim 1, wherein the connecting member is formed of a member that can be elastically extended.