JPH0780651A - Electrode pressing unit for resistance welding machine - Google Patents

Abstract

PURPOSE:To easily carry out assembly of an electrode pressing device and recombination to others by uniting a driving mechanism of an electrode pressing system consisting of an electrode driving shaft, an electric motor, etc., with a base fitted to the welding machine main body side. CONSTITUTION:A gun arm 2 and a bracket 3 are tightened tightly in the lump by a bolt 9a via an insulating plate 4 to form a gun main body and the base 8 is fixed on the bracket 3 by a bolt 9b. The electric motor 10 and an angular bearing 11 are fixed on the base 8 by a bolt 9c, the electric motor 10 outputs the turning force as a pressing source of electrodes 20 and 22 and the angular bearing 11 converts this turning output into reciprocating linear motion. Bearings 5 and 19 fitted to bolt sides of the base 8 to guide and baffle a ball screw 15 and the electrode 20 is fixed on the tip of the ball screw 15 via a point holder 21. Consequently, the whole electrode pressing unit can be pulled out rearward entirely by removing the base 8 from the bracket 3 of the gun main body.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrode pressurizing unit using an electric motor as a pressurizing drive source for electrodes of a resistance welding machine such as a stationary spot welding machine, spot welding gun, seam welding machine, etc. In order to adapt the electrode pressurizing device to spot welding gun variations, the electrode pressurizing drive mechanism has been unitized to facilitate gun assembly and maintenance.

[0002]

2. Description of the Related Art It is well known that a pressurizing system using a fluid pressure cylinder or an electric motor is generally adopted as a pressurizing drive source for an electrode of a resistance welding machine. An electrode pressurizing system and device using an electric motor are disclosed in, for example, JP-A-61-186177 and JP-A-63-19908.
No. 6, Japanese Patent Publication No. 3-50631, and Japanese Patent Laid-Open No. 3-20758.
No. 0, Actual Kaihei 3-106279, Actual Kaihei 4-471
No. 4, U.S. Pat. No. 4,75,674, JP-A-5-138366.
Inventions and devices based on Japanese Patent Publications and the like are known.

[0003]

However, in all of the conventional electric pressurizing devices for spot welding guns, the electrode driving mechanism is not unitized. In general, components such as a ball nut bearing and a transmission mechanism such as a drive belt and a belt gear are incorporated inside the main body. Therefore, it is difficult to assemble and adjust (tension of the drive belt, etc.). Moreover, since it is difficult to mass-produce, the manufacturing cost is high. In addition, it takes time to perform maintenance (especially, replacement of drive parts), resulting in high maintenance cost. Therefore, regardless of the variation of the gun body, how to make the electrode drive mechanism such as the electric motor and the ball screw compact and unitize it to solve the above problems is an important issue.

[0004]

The present invention was developed in order to solve the above problems and takes the following technical means.

That is, in an electrode pressurizing device using an electric motor as a pressurizing source of an electrode of a resistance welding machine, an electrode drive shaft in which a ball screw is incorporated into a ball nut for converting the rotational force of the motor into a reciprocating linear motion. The power transmission mechanism for transmitting the power of the motor to the electrode drive shaft, and / or the motor in addition to these machines are unitized on a base mounted on the main body of the welding machine.

Also, the power transmission mechanism can be housed inside the base.

Further, the base is provided with a bearing having a ball screw rotation preventing function.

Also, the base is provided on the side symmetrical to the electrode of the main body of the welding machine.

Further, according to the present invention, the electrode driving mechanism including the electrode driving shaft and the electric motor is made into a common component, and the common unit component is easily assembled or exchanged in common for the variations of the spot welding gun. By simply changing the electrode pressurizing device, the efficiency of the gun assembly and maintenance work is dramatically improved, and the weight and size of the gun are reduced.

[0010]

1 is a side view showing an embodiment of the device of the present invention. FIG. 2 is a plan view. FIG. 3 is a sectional view showing an embodiment of the device of the present invention. FIG. 4 is a view on arrow AA of FIG.

FIG. 1 is a general term for a C type spot welding robot gun. The gun body is tightly fastened together with the gun arm 2 and the bracket 3 by the bolt 9a with the insulating plate 4 interposed therebetween. A robot mounting seat 6 is provided on the bracket 3, and a robot arm (not shown) is connected to the seat surface. Reference numeral 7 indicates an electrode pressing unit.

Reference numeral 8 indicates a base. The bracket 3 of the main body is configured as a unit part so that it can be commonly attached to various types of guns so as to cope with variations of spot welding guns. The base 8 is detachably fastened from the bracket side by bolts 9b.

The base 8 may be divided into two parts on the electrode drive shaft side and the electric motor side so that the timing belt tension can be set as shown in FIG. 1, and substantially as shown in FIG. It may be an integral body having a size such that the shaft and the electric motor can be attached together.

Although not shown in this embodiment, when the bracket 3 and the gun arm 2 are integrally formed of one conductive casting material, an insulating plate 4 is interposed between the base 8 and the bracket 3. The bolts 9b are collectively and firmly tightened.

In addition, since the equalizing unit is not required in this embodiment, it is not necessary to attach the robot mounting seat 6 via the equalizing unit. Therefore, the robot mounting seat 6 can be mounted anywhere except for the ball screw portion that moves linearly.

An electric motor 10 and an angular bearing 11 are fixed to the base. The electric motor 10 outputs a rotational force as a pressure source for the electrodes, and the angular bearing 1
Reference numeral 1 is for converting the rotational output of the motor 10 into a reciprocating linear motion, and a smooth rotational motion is obtained through a housing 12 fixed to the base 8 by a bolt 9c and an angular bearing 13 in the housing. It is composed of a ball nut 14. The electrode drive shaft that is converted into linear motion is constructed by incorporating a ball screw 15 into the ball nut 14, for example.

In the case of this embodiment, the power transmission mechanism is such that the belt gear 16 and the belt gear 17 attached to the output shaft of the motor 10 and the ball nut 14 are in the thickness direction of the base 8 (plate width e). The timing belt 18 is stretched between the two gears. The rotational force of the electric motor 10 is the timing belt 1
The ball nut 14 is rotated via 8 to give a linear movement to the ball screw 15.

The same effect can be obtained by using a chain transmission system or a combination of gear type transmissions instead of the timing belt of this embodiment as the power transmission mechanism.

Bearings 5 incorporated into a ball screw such as a ball spline and bearings 19 fixed to the housing side are mounted on both sides of the base 8. The bearing 5 and the bearing 19 guide the ball screw 15 from both sides of the base, and also share the rotation preventing function. Reference numeral 20 is an electrode fixed to the tip of the electrode drive shaft via a point holder 21. Reference numeral 22 is an electrode fixed to the tip of the gun arm. Reference numeral 23 denotes a shunt that constitutes a secondary circuit for energizing the electrodes.

In the device of the present invention having such a structure, the electrode drive shaft including the electric motor 10 and the ball screw 15 is attached to the upper side of the base 8 and the bearing 19 of the electrode drive shaft is fixed to the lower side of the base. If 8 is removed from the bracket 3 of the gun body, the entire electrode pressurizing unit can be pulled out completely backward.

When the timing belt 18 is replaced, the electric motor 10 is removed with the belt gear 16 and the belt gear 17 still attached, and the bolt 9c of the housing 12 of the angular bearing 11 of the ball nut 14 is loosened and moved backward. There is a gap, and the timing belt 18
Can be pulled out rearward by passing through the housing 12. When checking the tension of the timing belt 18,
It can be confirmed from the rear between the housing 12 of the angular bearing 11 of the ball nut 14 and the electric motor 10. If you have a two-piece base, you can check the gap in the base.

In the case of the present invention, since the mounting position of only the electric motor 10 around the ball screw 15 can be changed to any direction in the radial direction around one side of both sides of the base or around the ball screw, the gun arm can be changed. The design structure corresponding to the variation such as the shape change of the bracket 2 and the bracket 3 is also facilitated.

[0023]

As described above, according to the device of the present invention, the drive mechanism of the electrode pressurizing system such as the electrode drive shaft and the electric motor is unitized to the base mounted on the welder body side. ， The electrode pressurizing device can be easily assembled or recombined to another one regardless of the variation of the resistance welding machine simply by exchanging the common unit parts, and the power transmission mechanism (timing belt, gear, chain, etc.) ) Is housed inside the base to achieve compactness, and maintenance work such as replacement of drive parts of the power transmission mechanism and adjustment of belt tension is dramatically facilitated. In addition, the standardization of the electrode drive mechanism by the common parts configuration has been realized, and the cost has been significantly reduced.

[Brief description of drawings]

FIG. 1 is a side view of the entire welding gun showing an embodiment in which the apparatus of the present invention is applied to a spot welding robot gun.

FIG. 2 is a plan view of the device of the present invention. .

FIG. 3 is a sectional view showing an embodiment of the device of the present invention.

FIG. 4 is a view on arrow AA of FIG.

[Explanation of symbols]

1 Spot welding robot gun 14 Ball nut 2 Gun arm 15 Electrode drive shaft (ball screw) 3 Bracket 16,17 Belt gear 4 Insulation plate 18 Timing belt 5 Bearing 19 Bearing 6 Robot mounting seat 20,22 Electrode 7 Electrode pressure unit 21 Point holder 8 Base 23 Shunt 9a-9c Bolt 10 Electric motor 11 Angular bearing 12 Ball screw 13 Angular bearing

Claims (4)

[Claims] 1. An electrode pressing device using an electric motor as a pressure source for an electrode of a resistance welding machine, wherein an electrode driving shaft having a ball nut incorporated with a ball screw for converting the rotational force of the motor into a reciprocating linear motion. A resistance characterized by unitizing a power transmission mechanism for transmitting the power of the motor to an electrode drive shaft and / or the motor in addition to these machines to a base attached to the main body of the welding machine. Electrode pressure unit for welding machine. 2. The electrode pressing unit according to claim 1, wherein the power transmission mechanism can be housed inside the base. 3. The electrode pressing unit according to claim 1, wherein the base is provided with a bearing having a rotation preventing function of a ball screw. 4. The electrode pressing unit according to claim 1, wherein the base is provided on a side symmetrical to the electrode of the main body of the welding machine.