JP3290609B2 - Resistance spot welding machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrode pressing device using an electric motor as an electrode driving source of a resistance welding machine for a spot welding gun. The pressure drive mechanism for the electrodes has been unitized so that it can be handled by the device, making the gun compact and easy to maintain.

[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 used as a pressurizing drive source for resistance welding electrodes. An electrode pressurizing system and apparatus using an electric motor are disclosed in, for example, JP-A-61-186177 and JP-A-63-199086.
No., JP-B-3-50631, JP-A-3-207580
No., Japanese Utility Model No. 3-106279, Japanese Utility Model No. 4-471,
The inventions disclosed in Japanese Utility Model Laid-Open No. 4-75674, Japanese Patent Laid-Open No. 5-138366, and the like are known.

[0003]

However, in any of the conventional electric pressurizing devices for spot welding guns, the electrode press driving mechanism is not unitized. Ball Ne
Di nut, the ball screw and its rotation stopper of parts and drive belts, belt gear, etc. of the transmission mechanism is incorporated in the main body are common. Therefore, it is difficult to assemble or adjust (the tension of the driving belt). Also, since mass production is difficult, production costs are high. In addition, it takes time to perform maintenance and improve accuracy (especially, replacement of driving parts), resulting in high maintenance costs. Therefore, irrespective of the variation of the gun body, how to make the pressure driving mechanism of the electrodes such as the electric motor and the ball screw compact and unitized to solve the above problem becomes a problem.

[0004]

SUMMARY OF THE INVENTION The present invention has been developed to solve the above-mentioned problems, and employs the following technical means. That is, pressurization of the electrode of the spot welder
Or an electric motor performing an opening operation and a rotation of the electric motor.
Converts rolling force into reciprocating linear motion.
Electrode drive shaft with a screw
A power transmission mechanism for transmitting power to the electrode drive shaft;
The electrode pressure drive mechanism including the rotation stop of the drive shaft is
Removably attached to the support bracket or gun arm side of the machine.
Unitized so that it can be attached
The electric motor included in the pressurizing unit is
Between the gun arm side and the end of the casing of the drive shaft
Between the base plate and the end plate.
It is characterized by having been done .

[0005]

According to the present invention, the electrode pressure drive mechanism including the electrode drive shaft and the electric motor is made into a common component, and this common unit component can be easily assembled in common to the variations of the spot welding gun. In addition, the efficiency of gun assembling and maintenance can be dramatically improved, for example, the replacement of the electrode pressurizing device can be easily achieved by simply replacing the gun. In addition, the weight and size of the gun can be reduced.

That is, according to the present invention, most of the electrode pressurizing units are provided by simply providing a set of spare units, taking advantage of the feature that the opening stroke and the pressing force of the electrode pressurizing drive mechanism can be freely changed. It can be mounted on a mass production line because of its compatibility with, so that significant cost reduction is possible.

[0007]

FIG. 1 is an external view of a robot gun with a transformer showing a first embodiment of the present invention. FIG. 2 is a side view showing the unitized electrode pressing device.

Reference numeral 1 denotes a transformer-equipped robot gun in which a C-type robot gun and a welding transformer 2 are assembled via an equalizing device 11. Reference numeral 3 denotes an electrode pressing unit. The anti-rotation mechanism has two anti-rotation rods 5 connected to both sides of the point holder 6 in parallel with the electrode drive shaft 7, and penetrates through the anti-rotation bush 9 fixed to the casing 8. It prevents rotation.

The structure of the gun arm 12 includes one electrode 13
And the drive for supporting the other electrode 14
A bearing 15 also serving as a rod cover for supporting a casing 8 having a built-in shaft 7 is integrated.

[0010] The equalizing device 11 has a gun arm side and the above
Supports the bearing 15 on the rod cover side of the casing 8
Both ends between the support bracket 17 and the end cover 18
Two fixed equalizing shafts 19 are fixed to the robot side
Through the bearing of the guided member 20
This is to support the collising operation.

An electric motor 10 used as an electrode pressurizing actuator is disposed between the gun arm 12 and an end portion 18 of the casing 8, and a base of the end portion 18 is provided.
It is attached to the plate 22 via a plurality of bolts B1.

A belt gear 23 is mounted on the output shaft of the electric motor 10. An electrode 14 is supported at the tip of the electrode drive shaft 7 via a point holder 6.

[0013] The rear electrode drive shaft 7 the ball screw nut 25 as a component constituting the power transmission mechanism has not been fixed, the end portion on the inner diameter of the ball screw nut 25 18
A ball screw 28 penetrating a bearing 27 incorporated in the base plate 22 is incorporated.

A belt gear 29 constituting one of the power transmission parts is attached to the tip of the ball screw 28, and the belt gear 23 provided on the output shaft of the electric motor 10 is connected to the belt gear 29 of the ball screw 28. Are connected to the timing belt 30, respectively.

The power transmission mechanism of this embodiment, the electric motor 10 of the output shaft and the ball screw nut 25 and the attached belt wheel 23 and the belt gear 29 is in the dimension in the thickness direction of the base plate 22 And a timing belt 30 is stretched between the two gears. The rotational force of the electric motor 10 provides linear motion to the rotating ball screw 28 and the ball screw nut 25 via a timing belt 3.

The same operation can be obtained by using a chain transmission type or a combination of gears transmission mechanisms instead of the timing belt of the present embodiment.

In this case, the electrode pressurizing unit 3 releases the bolt tightening force between the end portion 18 and the equalizing shaft 19, and removes the bolt (see FIG. 4) from the mounting surface of the support bracket 17 into which the bearing 15 of the electrode driving shaft 7 is inserted. The electrode pressing unit 3 shown in FIG.

Next, FIG. 3 shows another embodiment. Basically, there is no change from the unit configuration shown in the previous figure. In this case, however, it differs in that a detent mechanism is built in the casing 8 and the equalizing device 11 of the preceding example is not provided.
It is brewing things. In this configuration example, the bolt B is attached to the support bracket 17 on the robot side from the mounting surface symmetrical to the electrode side.
By unscrewing 2, the entire electrode pressing unit 3 shown in FIG. 4 can be removed.

FIG. 5 shows an enlarged cross section of FIG. As can be seen from this cross-sectional view, the two detent rods 31 are fixed at both ends to a rear cover 33 of the casing 8 and a front cover 34 attached to the support bracket 17. Ball nut 25 fixed to the rear of electrode drive shaft 7
When translatory movement by the detent detent bush 35 the rod 31 penetrates is fixed and the electrode drive shaft 7 the ball screw nut 25 in rotary motion of the ball screw 28 incorporated in the ball screw nut 25 to, The detent bush 35 firmly guides the two detent rods 31 to prevent the electrode drive shaft 7 from rotating.

The above-mentioned electrode pressurizing unit of the present invention is not limited to the above-mentioned embodiment, but can be easily mounted on the upper arm of a stationary spot welding machine, a projection welding machine, a seam welding machine or the like. Various design changes are also easy.

[0021]

As described above, according to the apparatus of the present invention , the electrode pressurizing actuator of the resistance spot welding machine is used.
The electric motor used as the casing of the electrode drive shaft
Between the base plate at the end and the gun arm side
Connect the electrode pressure drive mechanism to the support bracket or
Is unitized so that it can be attached to the gun arm side.
This allows the common unit parts to be electrically pressurized
Easy and common assembly for welding gun variations
A set of electrode pressing devices that can be easily attached or replaced
Replacement can be obtained, such as gun assembly and maintenance
In addition to dramatically improving work efficiency, reducing the weight and cost of the gun
Improve impact.

[Brief description of the drawings]

FIG. 1 is an external view of an entire robot welding gun with a transformer having an equalizing device showing an embodiment of the present invention.

FIG. 2 is an external view of the electrode pressing unit of FIG.

FIG. 3 is an external view of the entire robot gun with a transformer showing another embodiment of the device of the present invention.

FIG. 4 is an external view showing the electrode pressing unit of FIG. 3;

FIG. 5 is an enlarged cross-sectional view taken along the line AA of FIG. 4;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Spot welding gun 2 Welding transformer 3 Electrode pressurization drive mechanism (electrode pressurization unit) 7 Electrode drive shaft 8 Casing 10 Electric motor 11 Equalize mechanism 12 Gun arm 13 Electrode 14 Electrode 17 Support bracket 18 End part 22 Base plate

Claims (1)

(57) [Claims] 1. An electrode press of a spot welding machine or an opening and closing movement of the electrode.
Reciprocating the rotational force of the electric motor
Convert to linear motion, ball screw to ball screw nut
The built-in electrode drive shaft and the power of the electric motor
A power transmission mechanism for transmitting to the drive shaft,
An electrode press drive mechanism including a stopper is supported by the welding machine.
Removably attached to bracket or gun arm side
Unit and included in the electrode pressing unit
The electric motor is connected to the gun arm side of the welding machine and the drive
Disposed between the shaft and the end of the casing, and
It is attached to the base plate at the end part.
That resistance spot welding machine.