JP2002178160A - Arm supporting surface of motor driven x-shaped gun - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an arm supporting structure of a motor driven X-shaped gun which has a stationary arm and a moving arm, is imparted with durability to moment load by enlarging the central spacing distance of the outermost side bearing of two or more pieces of needle bearings for pivoting the moving arm and is capable of surely supporting the motor driven X-shaped gun with simple constitution. SOLUTION: The arm supporting structure of the motor driven X-shaped gun which pivots the intermediate part of the moving arm of the two gun arms; the stationary arm 1 and moving arm 3 having electrodes facing each other at their front ends by a supporting shaft 5 and makes the moving arm freely turnable around the supporting shaft as a fulcrum by a pressing driver operated by an electric motor is constituted by pivoting the pivot part of the moving arm at the supporting shaft by means of two or more pieces of the needle bearings 15, arranging gun brackets 7 through thrust washers 18 at the respective outer sides of the moving arm and setting and central spacing size L of both outermost side bearings of the moving arm at least times larger than the shaft diameter D of the bearings.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a fixed arm and a movable arm provided with electrodes opposed to each other at a tip thereof, and an intermediate portion of the movable arm is supported by a support shaft. An arm of an electric X-type gun which is pivotally supported, the fixed arm is formed integrally with a gun bracket, and the movable arm is rotatable about the support shaft as a fulcrum by a pressurizing drive device using an electric motor. This is related to the support structure of the system.

[0002]

2. Description of the Related Art A fixed arc provided with opposing electrodes at its tip.
An intermediate portion of the movable arm of the two arm arms, a movable arm and a movable arm, is supported by a support shaft, and the fixed arm is integrally formed with a gun bracket; In an electric X-type gun in which the arm is rotatable about the support shaft by a pressurizing drive device by an electric motor, a shaft support portion of the movable arm is supported by the support shaft via two bearings, One in which gun brackets are arranged on both outer sides of a movable arm is known, for example, as disclosed in JP-A-2000-94142.

[0003]

In the prior art, since the distance between the centers of the two bearings of the movable arm is substantially equal to the diameter of the bearing shaft, the movable arm receives a moment load from the movable arm side. The load distribution in each bearing locally increases near the outer end of each bearing, and the load applied to the outer end of the bearing is significantly increased. As a result, a misalignment may occur between the upper and lower electrodes of the X-type gun, and the strength of the welding nugget may not be secured.

The present invention has been made in view of the above-mentioned problems of the prior art, and an object of the present invention is to provide an electric X-type gun having a fixed arm and a movable arm. In two or more needle bearings that support the movable arm, the center distance between the outermost bearings has been increased to provide durability against moment loads, and a simple structure ensures reliable support. An object of the present invention is to provide an arm supporting structure for an electric X-type gun.

[0005]

In order to achieve the above object, an arm supporting structure for an electric X-type gun according to the present invention comprises:
An intermediate portion of the movable arm is supported by a support shaft among two gun arms of a fixed arm and a movable arm having electrodes opposed to each other at a tip, and the fixed arm is gunned. An electric X-type gun, which is integrally formed with a bracket, and in which the movable arm is rotatable about the support shaft by a pressurizing drive device by an electric motor, the movable arm has two or more shaft support portions. And the gun bracket is arranged on each outside of the movable arm via a thrust washer, and a center distance between both outermost bearings of the movable arm. The dimensions are at least twice as large as the bearing shaft diameter.

[0006]

Embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a schematic front view of an electric X-type robot gun having an arm supporting structure according to the present invention, FIG. 2 is a side view thereof, and FIG. 3 is a detailed view of a shaft support of each arm.

1 to 3, reference numeral 1 denotes a fixed arm which is one of the gun arms provided with an electrode 2 at the tip,
Reference numeral 3 denotes a movable arm of the other gun arm provided with an electrode 4 facing the electrode 2 at the tip. And the movable arc
An intermediate portion of the drum 3 is supported by a support shaft 5. Also,
The fixed arm 1 has an intermediate portion pivotally supported by the support shaft 5 and a bolt 6
The arm 1 is fixed to the gun bracket 7, and the fixed arm 1 is integrally formed with the gun bracket 7.
The rear end of the gun bracket 7 is connected to a wrist of a robot (not shown).

Reference numeral 8 denotes a motor for driving the movable arm 3. A pressure driving unit main body 9 is connected to the output side of the motor 8 via a belt which is a well-known transmission mechanism. The distal end of the driving rod 10 is pivotally connected to the rear end of the fixed arm 1 via a screw shaft and a nut in the pressure driving unit main body 9, and the movable surface is mounted on the outer surface of the pressure driving unit main body 9. A
The rear end 12 of the drum is pivoted 13. Reference numeral 14 denotes a welding transformer, on the secondary side of which an electric circuit for conducting the fixed arm 1, the electrode 2, the electrode 4 and the movable arm 3 is formed. I have.

The details of the support of the intermediate portion of the movable arm 3 to the support shaft 5 are as shown in FIG. 3, for example. That is, the middle part of the movable arm 3 is branched into two branches, and at each branch end, the movable arms 3 and 3 are supported by the support shaft 5 via needle bearings 15 and 15, respectively. I have. The middle part of the fixed arm 1 is an insulating bush 1
6 is supported by the support shaft 5.

Further, both side surfaces of the fixed arm 1 are configured to slide with respect to thrust washers 17, 17, and both side surfaces of the movable arm 3 are formed with the thrust washer 17 and the thrust washer 18 respectively. The two washers 17, 18 are fixed to the movable arm 3 by detent pins 19, 19, respectively. The gun bracket 7 is disposed via the thrust washer 18 on the outer surface of the movable arm 3, and the thrust washers 18, 18 slide on the outer surface of the gun bracket 7 respectively. ing. Reference numeral 20 denotes a dust seal, and reference numeral 21 denotes a cooling water passage.

Then, the two needle bearings 15, 15
Is at least twice as large as the diameter D of the bearing shaft.
When using more than one, use these needle bearings 1
The center distance between the outermost centers of both of Nos. 5 is L. Also,
L / D is desirably set to 5 or less in view of the restriction on the outer width of the gun bracket 7 and the increase in the overall weight of the gun.

In the electric X-type gun having the above-described configuration, when the electric motor 8 is driven from the state shown in FIG. Performs an opening operation with the support shaft 5 as a fulcrum, and enters an open state as indicated by a virtual line. In order to cause the gun to perform a pressurizing operation, the motor 8 is rotated in the reverse direction so that the drive rod 10 is sequentially protruded from the pressurizing drive unit main body 9. Perform the operation.

During the pressurizing operation, in particular, when the work is pressurized, a moment load is applied to the needle bearing 15 from the movable arm 3 side.
However, in the present invention, the distance L between the centers of both outermost bearings of the movable arm 3 is at least twice as large as the bearing shaft diameter D in the present invention. Movable arm 3 compared to arm support structure of type gun
The width of the bearing is increased, the load on the bearing is reduced, the bearing 15 and the support shaft 5 are less damaged, the movable arm 3 is prevented from rattling, and the effect of the amount of misalignment between the electrodes 2 and 4 is reduced. Can be kept small.

The gun bracket 7 is disposed at least on the outer surface of the movable arm 3 near the axial support of the intermediate portion to the support shaft 5 via a thrust washer 18, so that the thrust washer is provided. 18 prevents the spatter or the like from entering the needle bearing 15, and there is no possibility that the spatter or the like enters the needle bearing 15 during welding work.

FIG. 4 shows another embodiment of the arm supporting structure of the electric X-type gun according to the present invention, which is different from the previous embodiment in the means for integrating the fixed arm 1 to the gun bracket 7. However, members that are substantially the same as those in the previous embodiment will be described with the same reference numerals.

The middle part of the movable arm 3 is branched into two branches,
At each branch end, the movable arms 3 and 3
It is supported by the support shaft 5 via the dollar bearings 15 and 15. Further, a thrust washer 18 is fixed to each outer surface of the movable arm 3.
Each of the thrust washers 18 slides on the outer surface thereof with respect to the gun bracket 7. A spacer 30 is arranged between the two needle bearings 15 to ensure that the distance between the two bearings 15 is maintained. The fixed arm 1 is an insulating bush 3
1 directly on the gun bracket 7 by the bolt 32
It is stuck to.

Also, in the case of this embodiment, the movable arm
Since the distance L between the centers of both outermost bearings of the system 3 is at least twice as large as the bearing shaft diameter D, the conventional electric X
The width of the bearing of the movable arm 3 is larger than that of the arm supporting structure of the die gun, the load applied to the bearing is reduced, and the bearing 15 and the support shaft 5 are less damaged.
Is prevented, and the influence of the amount of misalignment between the two electrodes can be reduced. Further, there is no possibility that spatter or the like may enter the needle bearing 15 during the welding operation.

[0018]

As described above, the present invention supports the intermediate part of the movable arm among the two gun arms of the fixed arm and the movable arm having the electrodes facing each other at the tip. An electric X-type gun which is supported by a shaft, the fixed arm is integrally formed with a gun bracket, and the movable arm is rotatable about the support shaft as a fulcrum by a pressurizing drive device using an electric motor. The movable arm is supported by the support shaft via two or more needle bearings, and the gun bracket is disposed on each outer side of the movable arm via a thrust washer; Since the distance between the centers of both outermost bearings of the movable arm is at least twice as large as the diameter of the bearing shaft, the width of the bearing of the movable arm is increased by a simple structure, and the load on the bearing is reduced. Bearing and support shaft loss Movable A less - is prevented rattling of the arm, prevents the misalignment between both electrodes due to prolonged use, yet two - dollar bearing those not worry about such damage by sputtering or the like.

[Brief description of the drawings]

FIG. 1 is a schematic front view of one embodiment of an electric X-type robot gun having an arm support structure according to the present invention.

FIG. 2 is a side view thereof.

FIG. 3 is a detailed view of a shaft support of each arm.

FIG. 4 is a shaft support diagram of each arm of another embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fixed arm 2, 4 electrode 3 Movable arm 5 Support shaft 7 Gun bracket 8 Electric motor 15 Needle bearing 18 Thrust washer L Center distance of outermost bearing D Bearing shaft diameter

Claims (1)

[Claims] 1. A movable arm of a gun arm comprising a fixed arm and a movable arm provided with electrodes opposed to each other at a tip thereof.
An intermediate portion of the arm is supported by a support shaft, the fixed arm is integrally formed with a gun bracket, and the movable arm is rotatable about the support shaft by a pressurizing drive device using an electric motor. In the electric X-shaped gun described above, the movable arm is supported on the support shaft via two or more needle bearings, and the movable arm is provided with a thrust washer on each outer side through a thrust washer. An arm supporting structure for an electric X-type gun, wherein a gun bracket is arranged, and a distance between centers of both outermost bearings of the movable arm is at least twice as large as a bearing shaft diameter.