JPH10323764A - Motor driven pressurized c gun for spot welding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify a gun assembly work and its maintenance, and to improve productivity and achieve a cost reduction by realizing a RL sharing driving unit so that the electric motor for the motor driven pressurized C gun for the spot welding does not interfere with a work and a jig. SOLUTION: The C gun for the spot welding is to conduct a spot welding for a work being held between an electrode tip 1 and another electrode tip 3. The driving unit comprises, the electric motor and an electric driving shaft 6 which activates an electrode pressure/release operation by the ball screw 16 and ball nut 17, and a casing 7 to store the driving shaft, and a transmission device which transfers the electric power of the motor to the electrode driving shaft. A common base 10, on which the electric motor is installed, is attached to the casing end 9, freely attachable or detachable, by a fastening means B2. Placement of the motor can thus be freely changed in 360 degree on a concentric circle against a driving shaft central line X-X.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric pressurized resistance welding machine, and more particularly, to an electric pressurized electric power source used in a spot welding C gun (hereinafter referred to as an electric gun) for driving an electrode tip for direct-acting pressurization. The present invention relates to a drive unit capable of arbitrarily changing a mounting position of a motor.

[0002]

2. Description of the Related Art Conventionally, an electric motor which directly pressurizes an electrode tip of an electric gun can be changed to an arbitrary position on the circumference of the same axis as a ball screw in order to avoid interference with a jig. Such an apparatus has been proposed by the same applicant as the present application (Japanese Patent Laid-Open No. 7-32159).

In the device disclosed in Japanese Patent Application Laid-Open No. 7-32159, a drive shaft of an electrode penetrates through a bearing provided at a front portion of a main body casing, and a head portion of a casing for housing the penetrated drive shaft. In order to prevent the electric motor included in the drive unit from hitting the work or the jig, the electric motor can be rearranged by replacing parts of the rear cover. is there.

The present invention shows a more specific structure so that the electric motor can be easily rearranged in this kind of gun.

[0005]

As is well known, a robot gun arranged on a spot welding line in an automobile assembly plant has a work and a jig,
In addition, the working conditions and the surrounding environment are different depending on the arrangement of peripheral devices. For this reason, in the current automobile assembly line, a gun dedicated to either the RL or the RL is prepared in order to avoid interference between the gun and a jig.

In the case of an electric gun as well, the mounting position of the electric motor incorporated in the drive unit is fixed to one of the right and left. RL could not be shared with conventional electric guns because of the problem of interference.

Therefore, according to the device disclosed in Japanese Patent Application Laid-Open No. 7-32159, the arrangement of the electric motor can be changed by replacing the rear cover of the casing with a new one. It is not practical because the number of work steps increases.

Accordingly, the present invention provides a single drive unit in which the arrangement of the electric motor can be arbitrarily and easily rearranged in the direction of 360 ° around the drive shaft of the electrode chip without replacing extra parts as in the prior art. To overcome the problem of interference with workpieces and jigs and to expand the practical use of the RL type electric pressure drive unit, and to realize the standardization of the drive unit on the manufacturing side to improve productivity and reduce costs. With the goal.

[0009]

SUMMARY OF THE INVENTION The present invention has been developed to achieve the above-mentioned object, and employs the following technical means.

That is, a required pressurizing force is generated between the electrode tip supported on one of the gun arms and the other electrode tip which performs a pressurizing or opening motion by a driving device supported on the other side of the gun arm. And a spot welding C gun for welding by passing a welding current between the two electrodes, the driving device comprising: an electric motor provided as a driving source for pressing / opening the electrodes; An electrode drive shaft for converting the rotary motion into a reciprocating linear motion by means of a ball screw and a ball nut to press or release the electrode, a casing housing the drive shaft, and a power transmission mechanism for transmitting the power of the electric motor to the electrode drive shaft And an electric pressurizing gun in which the electric motor included in the drive unit is mounted on a common base. This common base is detachably attached to the head portion of the casing via a fastening means, whereby the arrangement of the motor can be freely changed in a 360-degree direction on a circle concentric with the drive shaft center line XX. Features.

[0011]

According to the present invention, the arrangement of the electric motor can be freely changed in the direction of 360 degrees with respect to the center of the drive shaft, so that the left and right electric guns can be shared, and the specifications are fixed as in the prior art. There is no need to prepare special guns and their spare parts, and the use of the left and right electric guns dramatically improves the work efficiency of gun assembly and maintenance, contributing to a significant reduction in production costs.

[0012]

Embodiments of the present invention will be described below. FIG.
FIG. 2 is a view showing the entire front of a C gun for electric pressure spot welding and a cross section of a drive unit. FIG. 2 is a detailed sectional view of the drive unit. FIG. 3 is a view taken along the line YY of FIG. 2 with the cover of the drive unit removed.

The electrode tip 1 is supported on one side of a gun arm 2 made of a high-strength brass casting. The other electrode tip 3 is supported on the tip of an electrode drive shaft 6 that performs a pressurizing or opening motion by a driving device 5 supported on the other side of the gun arm via a support member 4. The C gun for spot welding generates a pressing force required for welding between two electrode tips by a driving device 5 to hold a work, and a welding current is applied between the two electrodes to perform welding.

The driving device 5 includes an electric motor M provided as a driving source for pressurizing and releasing the electrode tip 2, and converts the rotational motion of the electric motor into a reciprocating linear motion by using a ball screw and a ball nut to press or release the electrode. An electrode drive shaft 6 that operates, a casing 7 that houses the drive shaft, and a power transmission mechanism 8 that transmits the power of the electric motor to the electrode drive shaft.
The electric motor included in the driving device is mounted on a common base 10, and the common base is removably mounted on the head 9 of the casing 7, thereby forming one driving unit. It is.

The drive shaft 6 is housed in a casing 7 made of an aluminum alloy casting. The electrode drive shaft 6 is formed concentrically inside a front portion 11 of the casing 7 through which the electrode drive shaft 6 passes. Is stored. The tip of the electrode drive shaft 6 supports an electrode tip 3 which is directly pressurized for welding.

The casing 7 and the supporting member 4 are detachably fixed by a plurality of bolts B1 via an insulating plate. The support member 4 is made of a high-strength brass casting which also serves as a front cover for fixing the bearing 12 of the front part.

As the sliding bearing 12 provided on the front portion of the casing 7, a ball spline bearing which serves as a rotation stopper and a linear motion guide is used. The aforementioned electrode drive shaft 6
Is a ball spline shaft, and a ball nut 17 is fixed to an end. In the casing, a ball screw 16 penetrating a bearing 15 provided on the head portion 9 is incorporated in a ball nut 17 of the drive shaft 6.
The electrode drive shaft 6 has a sliding bearing provided at the front portion of the casing as a ball spline bearing 12 and a linear motion guide and a rotation stopper are integrated into a unit. The externally mounted rotation stopper mechanism is eliminated to eliminate electrode rotation. Consideration has been given to making the outer diameter of the casing 7 of the gun body including the shaft 6 thinner and lighter and smaller.

The common base 10 is made of an aluminum alloy casting and is removably fastened to the head 9 of the casing 7 by a plurality of bolts B2. Corresponding cut-holes make the ball screw 16 coaxial center line XX
Are provided at four positions at 90 ° pitches on the circumference of the circle.

The main body of the electric motor M is firmly fixed to the common base 10 with a plurality of bolts B3 (only six tap holes b3 corresponding to the bolts B3 are shown in FIG. 3). Common base 10
And a belt gear 18 fixed to the output shaft and a belt gear 19 fixed to the ball screw 16.
Are arranged in the space of the enclosure formed by the board width (e) of the common base.

An aluminum alloy casting cover 21 is detachably fastened to the outside of the common base 10 by a plurality of bolts B4. This cover prevents foreign matter from entering the transmissions and ensures safety. Further, by removing this cover, it is possible to easily inspect the belt of the power transmission mechanism 8 housed in the common base and replace parts of the transmission.

The power transmission mechanism 8 includes a timing belt 2 between a belt gear 18 and a belt gear 19 incorporated within a dimension (e) of the common base 10 in the plate width direction.
0 is set. The rotational force of the electric motor M rotates the ball screw 16 via the timing belt 20, and the rotational motion is converted to linear motion by the ball nut 17 to linearly move the electrode drive shaft 6.

The same operation can be obtained by using a power transmission mechanism 8 in combination with a chain transmission type or gear type transmission mechanism instead of the timing belt 20 of the present embodiment.

The gun body is made of a casing 7 as is well known in the art.
And an arm bracket 22 for mounting the robot. A welding transformer 24 is supported on the gun bracket 22, and a conductive member constituting a secondary circuit is attached to an output terminal of the welding transformer by a shunt 26 and / or a bus bar 27 at the tip of the gun arm 2 and the electrode drive shaft 6. Connected to the tip holder 25.

The case where the arrangement of the electric motor M in the above configuration is changed to the right or left side of the gun will be described. When the bolt B4 of the drive unit 5 is removed and the cover 21 is opened, the fixing bolt B2 of the common base 10 can be removed as it is, and the common base 10 can be removed from the head portion 9 of the casing 7 by 90 degrees in four directions. That is, it can be rotated by 90 ° to each position of a, b, c, d. By changing the direction of the common base 10 in this manner, the bolt B2 may be fixed at a position where the electric motor M can be avoided from the interfering object. That is, the common base 10 is detachably attached to the head portion 9 of the casing 7 accommodating the drive shaft 6 from the plurality of bolts B2 as a fastening means, so that the axis center line X of the drive shaft is provided.
If the mounting angle (direction) of the common base is changed in accordance with the pitch of the plurality of bolt holes in the 360-degree direction on the concentric circle with -X, the arrangement of the electric motor M can be freely changed from right to left or an intermediate position therebetween. Can be.

In the embodiment of the present invention, the common base 1
As the tightening means of 0, the cut holes and the tapped holes of the bolt B2 are provided at four positions at a 90 ° pitch in the circumferential direction around the center of the drive shaft. However, in order to further divide the arrangement interval of the electric motor, the tap for the bolt B2 is required. By narrowing the pitch of the holes and the cut holes, it is easy to rearrange the holes at an arbitrary angle.

[0026]

As described above, according to the apparatus of the present invention, the arrangement of the electric motor is three concentric with the center of the drive shaft.
Since the common base is detachably attached to the head of the casing via a fastening means so that it can be freely changed in the 60-degree direction, the same electric gun can be used for both left and right. There is no need to prepare dedicated guns with fixed specifications and spare parts, and standardization of the drive unit improves productivity and dramatically improves the efficiency of gun assembly and maintenance of electric guns. , Leading to cost reduction.

[Brief description of the drawings]

FIG. 1 is a sectional view of an electric pressurized spot welding C gun according to an embodiment of the present invention.

FIG. 2 is a sectional view showing an embodiment of the drive unit of the present invention.

FIG. 3 is a view taken in the direction of arrows Y in FIG. 2;

[Explanation of symbols]

 Reference Signs List 1 electrode tip 2 gun arm 3 electrode tip 4 support member 5 drive unit (drive device) 6 electrode drive shaft 7 casing 8 power transmission mechanism 9 head unit 10 common base 12 bearing 16 ball screw 17 ball nut 18 belt gear 19 belt gear 20 Timing bolt 21 Cover 22 Gun bracket 23 Equalize unit 24 Welding transformer 25 Tip holder 26 Shunt 27 Busbar

Claims (1)

[Claims] An electrode tip (1) supported on one side of a gun arm (2) and another electrode tip (3) that performs a pressurizing or opening motion by a driving device (5) supported on the other side of the gun arm. A spot welding C gun for holding a work by generating a necessary pressing force between the electrodes and applying a welding current between both electrodes to weld the same, wherein the driving device presses / releases the electrode tip. An electric motor (M) provided as a drive source, and the rotational motion of this electric motor is transferred to a ball screw (1).
6) and an electrode drive shaft (6) for converting the pressure into reciprocating linear motion by means of a ball nut (17) and for pressing or releasing the electrode, and a casing (7) for accommodating the drive shaft; Power transmission mechanism for transmitting to shaft (8)
And an electric pressurizing gun in which the electric motor included in the driving unit is mounted on a common base (10), the common base being a head unit (9) of the casing (7). ), Which is detachably attached via a fastening means, whereby the arrangement of the motor can be freely changed in a 360-degree direction on a circle concentric with the drive shaft center line XX. For C gun.