JP2001170774A - Stationary type welding equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent spatters from splashing by making the follow-up property of a movable electrode tip 11 satisfactory to the penetration of a work in the one constituted of the drive unit 6 of the movable electrode tip 11 of a stationary type welding equipment by a motor driven system drive unit whose drive source is a servomotor 8. SOLUTION: The drive unit 6 is allowed to freely movably up and down support by a support frame 5 fixed on a supporter 4 erected on a base by energizing the drive unit 6 by an energizing means 14 downward in the pressing direction of the work. Also, a regulation means 16 is provided, which regulates the upward movement of the drive unit 6 to the support frame 5 in a position where the upward movement has been set higher than a position where the energizing force of the energizing means 14 becomes equal to the set pressure force of the work at the time of indirect welding, and the comparatively high pressure force of the work, which is suitable for regular spot welding, can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stationary welding apparatus for mainly performing indirect welding.

[0002]

2. Description of the Related Art Indirect welding uses a back bar that receives a work, connects one pole of a welding power source to a movable electrode tip facing the back bar, and connects the other pole to the work. This is performed by energizing between the movable electrode tip and the work while the pressure is held therebetween.

In a stationary welding apparatus for performing such indirect welding, a back bar is provided on a base, and a drive unit for chips is fixed to a support frame fixed to the base.
The drive unit moves the movable electrode tip toward the back bar to press the work.

Here, as a drive unit, generally,
Although an air cylinder is used, an electric drive unit that moves the movable electrode tip up and down by a motion conversion mechanism such as a feed screw mechanism using a servo motor as a drive source to enable fine pressurization control It is also considered to be used.

[0005]

When the electric drive unit is used as described above, the operation delay of the movable electrode tip occurs due to the inertia of the rotor of the servomotor or the backlash of the motion conversion mechanism. The movable electrode tip does not properly follow the melting of the work at the time, and the spatter is liable to be scattered.

SUMMARY OF THE INVENTION In view of the above, it is an object of the present invention to provide a stationary welding apparatus that enables fine pressure control using an electric drive unit and prevents scattering of spatter. And

[0007]

Means for Solving the Problems In order to solve the above problems,
The present invention provides a back bar for receiving a work on a base, and a driving unit that presses the work by moving the movable electrode tip downward toward the back bar on a support frame fixed to the base, A stationary welding device that performs indirect welding of the drive unit, wherein the drive unit is configured by an electric drive unit using a servo motor as a drive source, the drive unit is vertically movable on a support frame, and , And is urged downward by the urging means to be supported.

According to the present invention, when the movable electrode tip moves downward and comes into contact with the work, the driving unit moves upward against the support frame against the urging force of the urging means due to the contact reaction force, thereby driving the movable electrode tip. The upward movement of the drive unit is stopped at a position where the generated force of the unit and the urging force of the urging means are balanced. Eventually, the movable electrode tip receives the urging force of the urging means and presses the work with a pressing force equal to the generated force of the drive unit, and fine control of the pressing force by making the drive unit electric. Becomes possible. When the electric drive unit itself delays the operation of the movable electrode tip when the work is melted by energization, the movable electrode tip follows the work penetration by the urging force of the urging means and has good responsiveness, even if the operation delay of the movable electrode chip occurs. Movement and scattering of spatter are prevented.

When a fixed electrode tip is provided on the base in place of the back bar, normal spot welding can be performed by clamping the work between the movable electrode tip and the fixed electrode tip. Here, in indirect welding, it is desired to set the work pressure lower than that of normal spot welding so that no indentation is made on the contact surface of the work with the back bar. Therefore, the spring constant of the urging means needs to be set relatively low so that a relatively low work pressure suitable for indirect welding can be obtained. Therefore, it is difficult to obtain a high pressing force suitable for normal spot welding. In this case, if the regulating unit that regulates the upward movement of the drive unit with respect to the support frame at a position set higher than the position where the urging force of the urging unit is equal to the set pressing force of the work at the time of indirect welding is provided,
After the drive unit has moved up to the position regulated by the regulation means, the movable electrode tip directly receives the force from the drive unit and presses the work, and a high pressure suitable for normal spot welding is applied. can get. Thus, the welding apparatus can be used for both indirect welding and normal spot welding simply by replacing the back bar with the fixed electrode tip, which is advantageous in reducing equipment costs.

[0010]

FIG. 1 shows a vehicle door W as a workpiece.
Bent edge WOa of outer panel WO
1 shows a stationary welding apparatus for indirect welding to a door inner WI.

The welding apparatus includes a base 1, and a back bar 2 for receiving an outer surface of the outer panel WO is mounted on the base 1 via an insulating material 3. 4, a support frame 5 is fixed, and a drive unit 6 for chips is mounted on the support frame 5. Drive unit 6
Is composed of an electric drive unit in which a servo motor 8 as a drive source is mounted on a casing 7 containing a motion conversion mechanism (not shown) such as a feed screw mechanism. The rod 9 which is moved up and down through the projection is projected below the casing 7, and the movable electrode tip 11 is attached to the lower end of the rod 9 via the tip holder 10. Then, the movable electrode tip 11 is moved downward toward the back bar 2 by the operation of the servo motor 8, and the bent edge W of the outer panel WO having the outer surface received by the back bar 2.
The movable electrode tip 11 is brought into contact with Oa from above so that the hemming portion of the door W can be pressed.

Although not shown, the door W is a door inner WI.
A welding power source (not shown) in which the edge of the hole opened at the robot is held by the robot in a state of being gripped by a clamp member attached to the robot hand at the operating end of the robot, and one pole is connected to the movable electrode tip 11 (not shown) Is connected to the clamp member. Thus, when power is supplied from the welding power source while the hemming portion of the door W is pressurized as described above, a welding current flows from the movable electrode tip 11 to the door inner WI via the bent edge WOa, and the bent edge WOa is welded to the door inner WI. Is done.

Here, when the welding current is applied, the bending edge WOa
When the electric drive unit 6 is used, the movable electrode tip 11 does not move instantaneously even if the penetration occurs, so that the pressing force acting on the welding point is temporarily reduced. , And the spatter is liable to be scattered.

Therefore, in this embodiment, as shown in FIGS. 2 to 4, guide sleeves 7a, 7a formed on both sides of the casing 7 between the upper plate 5a and the lower plate 5b of the support frame 5.
a pair of vertically extending guide bars 1 to be inserted through a
The drive unit 6 is mounted on the support frame 5 so as to be movable up and down by attaching 2 and 12. Further, a vertically long spring guide 13 is attached to the support frame 5 so as to penetrate the protrusion 7b formed on the back surface of the casing 7, and the guide 13
The lower end of the collar 13a mounted on the upper part and the projection 7
The urging means 14 made of a coil spring is extrapolated between the upper surface of the support frame b and the urging means 14 to urge the drive unit 6 downward with respect to the support frame 5. Note that a balance spring 15 that receives the weight of the drive unit 6 is externally inserted below the spring guide 13.

According to the above configuration, the movable electrode tip 11
When the drive unit 6 comes into contact with the bending edge WOa by the downward movement, the drive unit 6 moves upward with respect to the support frame 5 against the urging force of the urging means 14 due to the contact reaction force. Then, the upward movement of the drive unit 6 is stopped at a position where the generated force of the drive unit 6 and the biasing force of the biasing unit 14 are balanced, and the movable electrode tip 11 receives the biasing force of the biasing unit 14 after all. Thus, the hemming portion of the door W is pressurized with a pressing force equal to the force generated by the drive unit 6. Thus, by applying the welding current, the bending edge WO
When the welding portion between the a and the door inner WI melts, the movable electrode tip 11 follows the melting by the urging force of the urging means 14 and moves with good responsiveness, thereby preventing the scattering of spatter.

In the stationary welding apparatus shown in FIG. 1, the fixed electrode tip 2 'is mounted on the base 1 in place of the back bar 2, as shown in FIG.
The work W 'is sandwiched between the electrode tip 2' and the fixed electrode tip 2 ', and is also used as a stationary welding apparatus for performing normal spot welding by energizing the work between the electrode tips 11 and 12' via the work W '. Can be.

Here, in the indirect welding, it is necessary to set the work pressing force to a relatively low value of 100 kgf or less so that no indentation is formed on the outer surface of the outer panel WO abutting on the back bar 2. Force means 14
Needs to be set relatively low. On the other hand, in normal spot welding, the work pressure is 150 k
It is necessary to set a relatively high value of gf or more. In this case, the moving stroke of the movable electrode tip 11 by the drive unit 6 is long, and the drive unit 6 can be moved up to a position where the urging force of the urging means 14 becomes equal to the work pressure required for normal spot welding. However, this would increase the size of the device.

Therefore, in the present embodiment, as shown in FIGS. 3 and 4, on the upper part of each guide bar 12, a rule means 16 composed of a cylindrical stopper capable of contacting the upper end of each guide sleeve 7a is mounted. The upward movement of the drive unit 6 is controlled by the urging means 1.
The regulating means 16 can regulate the urging force at a position slightly higher than a position at which the urging force of No. 4 is equal to the set pressing force of the workpiece at the time of indirect welding. According to this, when the drive unit 6 has moved up to the position regulated by the regulating means 16, the movable electrode tip 11 directly receives the force from the drive unit 6 and presses the work, so that the normal A high pressure suitable for spot welding can be obtained. Thus, indirect welding and common spot welding can be shared without increasing the size of the apparatus.

In the above-described embodiment, a coil spring is used as the urging means 14, but another urging member such as an air spring may be used.

[0020]

As is clear from the above description, according to the present invention, it is possible to use the electric drive unit to perform fine pressurization control and to make the movable electrode tip follow the work penetration. In addition, it is possible to prevent the spatter from being scattered, and by providing a regulating means for regulating the upward movement of the drive unit, it is possible to share indirect welding with normal spot welding without increasing the size of the equipment. Therefore, equipment costs can be reduced.

[Brief description of the drawings]

FIG. 1 is a side view of an example of the welding apparatus of the present invention.

FIG. 2 is an enlarged plan view of an arrangement portion of a drive unit.

FIG. 3 is a front view of the drive unit as viewed from the direction of arrow III in FIG. 2;

FIG. 4 is a side view cut along the line IV-IV of FIG. 2;

FIG. 5 is a side view showing a state where the welding apparatus of FIG. 1 is used as an apparatus for performing ordinary spot welding.

[Explanation of symbols]

 Reference Signs List 1 base 2 back bar 2 'fixed electrode tip 5 support frame 6 drive unit 11 movable electrode tip 14 biasing means 16 regulating means

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Koji Oda 1-10-1 Shinsayama, Sayama-shi, Saitama F-term (reference) in Honda Engineering Co., Ltd. 4E065 AA08 BA06 BB03

Claims (2)

[Claims] 1. A back bar for receiving a work is provided on a base, and a drive unit for pressing a work by lowering a movable electrode tip toward the back bar is mounted on a support frame fixed to the base. A stationary welding apparatus for performing indirect welding of a workpiece, wherein the drive unit is an electric drive unit using a servo motor as a drive source, wherein the drive unit is vertically movable on a support frame. A stationary welding device, wherein the device is urged downward by an urging means to be supported. 2. A back bar or a fixed electrode tip for receiving a work is provided on a base, and the movable electrode tip is moved downward on a support frame fixed to the base toward the back bar or the fixed electrode tip to move the work. A stationary welding device equipped with a drive unit for applying pressure and performing indirect welding or normal spot welding of a work, wherein the drive unit is an electric drive unit that uses a servo motor as a drive source. In the above, the drive unit is vertically movable on the support frame and is urged downward by the urging means to be supported, and the upward movement of the drive unit with respect to the support frame is performed when the urging force of the urging means is indirect welding. A stationary means for regulating at a position set higher than a position equal to the set pressure of the workpiece.