JPH1133745A - Dressing method for spot welding electrode - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the electrode quality and secure a welding strength with the usage of the electrodes by dressing the electrodes in a way that a pressurization power of the electrode having a larger dressing area is set stronger against that of the one having a smaller dressing area, thereby the both electrodes can be dressed uniformly. SOLUTION: When the upper electrode 10, having a larger dressing area, and the bottom electrode 12, having a smaller dressing area are dressed opposing each other, they are dressed having the pressurization power of the electrode 10 set at stronger than that of the electrode 12. Thereby, a pressing power per unit area against each electrode 10, 12 become even and the both electrodes 10, 12 are made to dress evenly. Quality of the electrodes 10, 12 can thus be improved and the life of the electrodes are prolonged. When the welding is conducted with the electrodes 10, 12, generation of spatters are reduced and the welding strengthness can be obtained. Furthermore, the pressurization power against the electrodes can easily be changed as a dress unit 19 is elastically held in the direction of the pressurization and changes the power is changed at the position when the dressing is started.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an electrode having a large diameter as a movable electrode (upper electrode) on the lot side and an electrode (so-called mini-tip) having a small diameter as a fixed electrode (lower electrode) on the arm side. The present invention relates to a spot welding electrode dressing method for dressing (dressing) electrodes having different dress areas between opposed electrodes.

[0002]

2. Description of the Related Art Conventionally, as a method of dressing a spot welding electrode, for example, there is a method described in JP-A-8-16888. That is, a welding robot controlled by the control device is provided, and while a welding gun is held at the tip of the robot arm of the welding robot, an electrode grinder (so-called dresser) is installed within the turning radius of the robot arm, and the tip of the robot arm is installed. The two electrodes facing each other of the welding gun held by the electrode grinding machine are positioned at the dressing position of the electrode grinding machine, and the two electrodes facing each other are driven at once by driving the rotary blade of the electrode grinding machine.

Here, as the above-mentioned welding gun, a normal welding gun in which both the upper electrode and the lower electrode have the same diameter is set, and the upper electrode is set to have a large diameter and the lower electrode is set to have a small diameter.
There are two types: a unique welding gun in which the dress areas of the vertically opposed electrodes are different. Although there is no problem when dressing each electrode in a normal welding gun having the same dress area by the above-mentioned conventional method, dressing each electrode of a unique welding gun having a dress area different from each other by the above-mentioned conventional method. When doing so, the following problems occur.

In other words, when the electrode is dressed, each electrode is dressed by applying a certain amount of pressure to the rotary blade having a double-edged structure of the electrode grinding machine.
Because the dress area of the small-diameter lower electrode is small, the pressure per unit area increases on the lower electrode side, and the cutting amount (dress amount) of the lower electrode becomes excessive, the consumption of the lower electrode becomes faster, and the electrode life is shortened. There was a problem of shortening.

Conversely, if the above-mentioned pressing force is made to correspond to the small-diameter lower electrode, the large-diameter upper electrode has a large dress area, so that the pressure per unit area becomes too small on the upper electrode side.
There was a problem that a good dressing effect of the upper electrode could not be obtained. It should be noted that the above-described unique welding gun performs spot welding by, for example, entering a small clearance at a front portion of a roof of a vehicle or the like, and is required to uniformly dress electrodes facing each other.

[0006]

According to the first aspect of the present invention, the pressing force of the electrode having the larger dress area is reduced.
By setting the dressing area to be larger than the pressing force of the electrode having the smaller dressing area, the pressure per unit area for each electrode becomes the same, and both electrodes can be dressed evenly. It is an object of the present invention to provide a spot welding electrode dressing method capable of improving the quality and securing the welding strength by using the electrode and improving the life of the electrode.

According to a second aspect of the present invention, in addition to the object of the first aspect, the dressing means is elastically supported in the pressing direction, and the pressing position (dressing means at the start of the dressing) is adjusted. It is an object of the present invention to provide a spot welding electrode dressing method in which the pressure applied to the opposing electrode can be changed by a simple operation by changing the applied pressure at the position where the pressure is applied.

According to a third aspect of the present invention, in addition to the object of the second aspect of the present invention, the above-mentioned dressing means is supported by a spring so as to be able to move forward and backward, so that it is applied against the spring force. It is an object of the present invention to provide a spot welding electrode dressing method that can easily adjust the pressure applied to each of the opposing electrodes only by changing the pressure position (the position where the dressing means is pressed).

According to a fourth aspect of the present invention, in addition to the object of the second aspect, the normal welding gun and the unique welding gun are changed by changing a pressurizing position by a gun change. It is an object of the present invention to provide a method of dressing a spot welding electrode capable of dressing both of the opposing spot welding electrodes in a good (uniform and uniform) manner.

[0010]

According to a first aspect of the present invention, there is provided a method for dressing spot welding electrodes for dressing electrodes having different dressing areas of opposing spot welding electrodes, wherein the dressing area of the electrode having the larger dressing area is used. The method is characterized by a spot welding electrode dressing method in which the electrode pressing force is set to be larger than the electrode pressing force of the electrode having a smaller dress area to dress.

According to a second aspect of the present invention, in addition to the configuration of the first aspect, a dressing means for dressing the electrode is provided, and the dressing means is elastically supported in a pressing direction. It is a spot welding electrode dressing method in which the pressing force is changed at a pressurizing position at the start of dressing.

According to a third aspect of the present invention, in addition to the configuration of the second aspect, the dressing means is a method for dressing a spot welding electrode supported by a spring so as to be movable forward and backward. Features.

According to a fourth aspect of the present invention, in addition to the configuration of the second aspect of the present invention, there is provided a method of dressing a spot welding electrode for changing a pressing position by a gun change.

[0014]

According to the first aspect of the present invention, when electrodes having different dress areas are dressed, the pressing force of the electrode having the larger dress area is applied to the electrode having the smaller dress area. Dress with a large setting for the pressure. For this reason, the pressure per unit area to each electrode becomes the same (equivalent), and as a result, both electrodes can be dressed uniformly, and the quality of the electrodes and the life of the electrodes can be improved. There is. Further, when spot welding is performed using the electrode thus dressed, the spatter (scattered particle) generation rate is greatly reduced, and thus there is an effect that the welding strength of the workpiece can be ensured. .

According to the invention described in claim 2 of the present invention,
In addition to the effect of the first aspect of the present invention, since the dress means is elastically supported in the pressing direction and the pressing force is changed at the pressing position (the position where the dress means is pressed) at the start of the dressing,
The pressure applied to the opposing electrodes can be changed by a simple operation, and the structure of the dressing means can be simplified.

According to the third aspect of the present invention,
In addition to the effect of the second aspect of the present invention, the above-mentioned dress means is supported by a spring so as to be able to move forward and backward.
By simply changing the pressure value (the position at which the dressing means is pressed) against the spring force, there is an effect that the pressure applied to the opposing electrodes can be easily adjusted.

According to the invention described in claim 4 of the present invention,
In addition to the effect of the second aspect of the present invention, since the pressurizing position is changed by a gun change, a normal welding gun (a welding gun in which the dress area of each facing electrode is equal) and a unique welding gun (a facing gun) are used. There is an effect that each spot welding electrode of a welding gun having a different electrode dress area can be uniformly and uniformly dressed.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to the drawings. The drawings show a method of dressing a spot welding electrode. First, a configuration of an apparatus used in this method will be described with reference to FIGS.

FIG. 1 shows a first gun 1 as a normal welding gun.
The first gun 1 has an upper electrode 3 that is moved (moves up and down) by operating a cylinder 2 and a lower electrode 5 that is fixed to an arm 4 so as to face the upper electrode 3 in the vertical direction.
, A welding transformer 6 and a robot connecting portion 7, the upper and lower electrodes 3, 5 are formed to have the same diameter, and the two electrodes 3, 5 are configured such that their dress areas are equal to each other.

FIG. 2 shows a second gun 8 as a unique welding gun.
The second gun 8 is moved by the operation of the cylinder 9 (the upper electrode 10 is moved up and down, and the lower electrode (the so-called mini chip) fixed to the arm 11 so as to face the upper electrode 10 in the vertical direction. A diameter D2 of the upper electrode 10 is equal to a diameter D2 of the lower electrode 12 as shown in FIG.
1 and the dress area of the upper electrode 10 is inevitably larger than the dress area of the lower electrode 12.
The dress areas are different from each other between 0 and 12.

However, as is apparent from FIG. 3, the diameters d of the portions of the upper and lower electrodes 10, 12 which are pressed against the work to be welded (work) are equal to each other. 4 and 5 show a dressing device (so-called dresser) for dressing each of the above-mentioned electrodes 3, 5, 10, and 12, and this dressing device 15 fixes a substrate 17 on a mounting surface 16, From two guide rods 18, 1
8, and a dress unit 19 is disposed so as to be vertically movable (movable forward and backward) with respect to these two guide rods 18.

That is, the unit base 21 is attached to the lower surface of the box 20, and through holes 22, 22 are formed in a portion where the unit base plate 21 extends beyond the box 20. Thus, the above-described guide rods 18, 18 are disposed in the through holes 22, 22, and a coil-shaped upper spring 23 is provided between the lower surface of the head 18 a of the guide rod 18 and the upper surface of the unit base plate 21. Stretched,
Another coil-shaped lower spring 24 is stretched between the lower surface of the unit base plate 21 and the upper surface of the substrate 17, and each spring 23, 24 wound on the guide rod 18 is used to provide an equalizer (equalizer, equalizer). ). That is, the above-mentioned dress unit 19 is elastically supported by the springs 23 and 24 in the direction of arrow a (vertical direction) in FIGS. 4 and 5, and the dress unit 19 can be moved forward and backward by the springs 23 and 24 (movable up and down). ).

By the way, a housing 25 is mounted so as to communicate with the box 20 described above, and the housing 25 is provided with a rotating blade 27 for a dress having a double blade structure via a bearing 26. A driven sprocket 28 is fitted on the outer peripheral portion of the rotary blade 27, while a driving sprocket 31 is fitted on a rotating shaft 30 of a reversible motor 29 installed in the box 20. The rotary blade 27 is rotated when the motor 29 rotates. It is needless to say that a gear drive type configuration may be used instead of such a chain drive type configuration.

Further, openings 33 and 34 are formed in the upper and lower portions of the housing 25 so as to face the above-mentioned rotary blade 27, and the electrodes 3, 5, and 1 are formed through the openings 33 and 34, respectively.
0 and 12 are configured to be pressed against the blade portion of the rotary blade 27.

FIG. 6 is a plan layout diagram showing a vehicle welding system, in which a welding robot 36 that can turn around a turning center 35 is provided, and the welding robot 36 having an eight-axis robot configuration is controlled by a control unit 37 (so-called robot controller). ).

The control unit 37 includes a CPU, a ROM, an R
While the bot arm 3 of the welding robot 36
At the distal end of the gun 8, a gun grip 39 is provided which is attached to and detached from the robot connection 7 of the first gun 1 or the robot connection 14 of the second gun 8, and is conveyed along the vehicle conveyance line 40 (for example, duct conveyance). The vehicle 41 is configured to perform spot welding by any one of the guns 1 and 8 gripped by the gun gripper 39.

Also, within the turning radius of the robot arm 38, a dressing section 42 in which the dressing device 15 is installed, a gun mount 43 for holding the first gun shown in FIG. 1, and a second gun 8 shown in FIG. 2 are held. A gun table 44 is provided. The above is the configuration of the example of the apparatus used in the spot welding electrode dressing method.

Next, the dressing method of the spot welding electrode will be described in detail with reference to the flowchart shown in FIG.
In a first step S1, the control unit 37 causes the welding robot 36 to wait at the origin position. At this point, the first gun 1 has already been gripped by the gun gripper 39 by repeating the flowchart of FIG.

Next, in a second step S2, the control unit 37 drives the robot arm 38 to move the first gun 1 to the welding position of the vehicle 41, and spot-welds a predetermined location with the pair of electrodes 3 and 5. I do. Next, in a third step S3, the control unit 3
7 executes a gun change via the welding robot 36. That is, the first gun 1 gripped by the gun gripper 393
Is once separated from the first gun 1 to the second gun 8 by holding the second gun 8 held on another gun mounting table 44 by the gun holding portion 39 after holding the second gun 8 on the gun mounting table 43. Perform a gun change.

Next, in a fourth step S4, the control section 37 drives the robot arm 38 to force the second gun 8 to enter the welding position of the vehicle 41, for example, from a small clearance at the front portion of the roof of the vehicle 41 or the like. And a predetermined location is spot-welded with the pair of electrodes 10 and 12.

Next, in a fifth step S5, the control unit 37 executes a gun change via the welding robot 36. That is, after the second gun 8 gripped by the grip portion 39 is once separated and held by the gun mounting table 44,
The gun change from the second gun 8 to the first gun 1 is performed by gripping the first gun 1 held by the first gun 1 with the gun gripper 39.

Next, in a sixth step S6, the control section 37 moves the welding robot 36 to the origin position. Next, in a seventh step S7, the control section 37 determines whether or not to dress. This determination is performed, for example, by comparing the predetermined number of weldings (the predetermined number of spots) with the actual number of weldings (the actual number of spots). When the determination is NO (when dressing is not performed), the first determination is made.
On the other hand, the process skips to step S12, and when YES is determined to execute dressing, the process proceeds to the next eighth step S8.

In the eighth step S8, the control section 37 turns the robot arm 38 holding the first gun 1 to the dress section 42, and moves the upper and lower electrodes 3 and 5 of the first gun 1 to FIG. As shown in the figure, the upper electrode 3 and the lower electrode 5 are simultaneously dressed by being pressed against the rotary blade 27 of the dress unit 19 and rotating the rotary blade 27 via the motor 29. In this case, the above-described springs 23 and 24 are substantially in a free state.

Next, in a ninth step S9, the control unit 37 executes a gun change via the welding robot 36. In other words, the first gun 1 after the dressing, which has been gripped by the gun gripper 39, is once separated and held on the gun mounting table 43.
By gripping the second gun 8 held on another gun mounting table 44 by the gun gripper 39, the first gun 1 to the second gun 8
Perform a gun change to

Next, in a tenth step S10, the control unit 37
Pivots the robot arm 38 holding the second gun 8 to the dressing section 42, and the upper and lower electrodes 1 of the second gun 8
9, the upper blade 10 and the lower electrode 12 are simultaneously dressed by rotating the rotary blade 27 via a motor 29 by pressing the rotary blade 27 of the dress unit 19 into pressure.

In this case, when the rotating blade 27 is gripped by the lower electrode 12 on the fixed side and the upper electrode 10 on the lower side moved down by the cylinder 9, the dressing unit 19 is moved by a predetermined amount L by teaching of the welding robot 36. 9 is pressed downward and pressed so as to apply pressure.
The upper electrode 10 having a large dress area
Of the lower electrode 12 having a small dress area is set.

That is, the force of the cylinder 9 of the second gun 8 is
Assuming that the reaction force of the spring 24 compressed by the pressing position is F2, the pressure of F1 + F2 acts on the upper electrode 10 and the pressing force of F1 acts on the lower electrode 12, so that the upper electrode 10 The pressure can be set to be larger than the pressure of the lower electrode 12. When dressing is performed under such conditions, the pressure per unit area on the upper and lower electrodes 10 and 12 becomes the same due to the size of the dress area, and both electrodes 10 and 12 can be dressed uniformly.

Next, in an eleventh step S11, the controller 37
Executes a gun change via the welding robot 36.
In other words, the second gun 8 after the dress is held by the gun holding unit 39 is once separated and held on the gun mounting table 44, and then the first gun after the dress held by another gun mounting table 43 is completed. The gun change from the second gun 8 to the first gun 1 is performed by holding the gun 1 with the gun holding unit 39.

Next, in a twelfth step S12, the controller 37
Makes the welding robot 36 stand by at the origin position under the condition that the first gun 1 is gripped by the gripper 39 at the tip of the robot arm 38, and ends a series of processing.

In summary, according to the spot welding electrode dressing method of the above embodiment, the electrode 1 having a different dress area is used.
When dressing 0 and 12, dressing is performed by setting the pressure of the electrode having the larger dress area (see the upper electrode 10) to be larger than the pressure of the electrode having the smaller dress area (see the lower electrode 12). . For this reason, the pressure per unit area for each of the electrodes 10 and 12 becomes the same (equivalent), and as a result, both the electrodes 10 and 12 can be dressed uniformly, and the quality of the electrodes 10 and 12 can be improved and the electrode life can be improved. There is an effect that can be improved. In addition, when spot welding is performed using the electrodes 10 and 12 thus dressed, the rate of spatter (scattered particles) generation is greatly reduced, so that the welding strength of the workpiece can be ensured. effective.

Further, dress means (dress unit 19)
Elastically supported in the pressing direction (vertical direction in FIG. 9)
Since the pressing force is changed at the pressing position (the position where the dress unit 19 is pressed) at the start of dressing, the pressing force on the opposing electrodes 10 and 12 can be changed by a simple operation, and the dressing means (dress unit) can be changed. 19) can be simplified.

Since the dress means (see the dress unit 19) is supported by the springs 23 and 24 so as to be able to move forward and backward (movable up and down in this embodiment), the force of this spring (especially see the lower spring 24) is applied. By simply changing the pressure value (the position at which the dress unit 19 is pressed), there is an effect that the pressure applied to the opposing electrodes 10 and 12 can be easily adjusted.

In addition, since the pressing position is changed by the gun change, the normal welding gun (refer to the first gun 1 in which the dress areas of the opposed electrodes 3 and 5 are equal) and the unique welding gun (the opposed There is an effect that the respective spot welding electrodes 3, 5, 10, and 12 of the second gun 8 having different dress areas of the electrodes 10, 12 can be evenly and uniformly dressed.

In the correspondence between the configuration of the present invention and the above-described embodiment, the electrode having a larger dress area according to the present invention is:
An electrode having a smaller dress area corresponds to the upper electrode 10 and the lower electrode 12 similarly.
Although corresponding to the dress unit 19, the present invention is not limited to only the configuration of the above-described embodiment.

For example, in the above embodiment, each electrode 3,
Although the electrodes of the CF type are disclosed as 5, 10, and 12, these may be other types of electrodes having different electrode shapes such as C type, R type, RF type, CR type, F type, and P type. .

In the flowchart of FIG. 7, when the determination in the seventh step S7 is YES, the electrodes 3, 5 of the first gun 1 are set.
And the electrodes 10 and 12 of the second gun 8 are configured to be dressed at the same time although there is a time lag. The electrodes of the gun may be configured to be dressed separately. Further, a screw portion may be formed on a part of the guide rod 18 described above, and an adjust nut may be screwed into the screw portion, and the force of the springs 23 and 24 may be finely adjusted by operating the nut.

[Brief description of the drawings]

FIG. 1 is a side view showing a first gun.

FIG. 2 is a side view showing a second gun.

FIG. 3 is an enlarged view showing a pair of spot welding electrodes having different dress areas.

FIG. 4 is a front view of the dressing device.

FIG. 5 is a sectional view taken along line AA of FIG. 4;

FIG. 6 is a schematic plan view showing a vehicle welding system.

FIG. 7 is a flowchart showing a dressing method of a spot welding electrode according to the present invention.

FIG. 8 is an explanatory view of the first gun at the time of electrode dressing.

FIG. 9 is an explanatory diagram of the second gun at the time of electrode dressing.

[Explanation of symbols]

 10, 12 ... electrode 19 ... dress unit (dress means) 23, 24 ... spring

Claims (4)

[Claims] 1. A method of dressing a spot welding electrode in which electrodes having different dress areas of opposed spot welding electrodes are dressed, wherein a pressing force of an electrode having a larger dress area is applied to a electrode having a smaller dress area. A dressing method for spot welding electrodes that is set with a large pressure. 2. A spot welding electrode according to claim 1, further comprising dress means for dressing said electrode, elastically supporting said dress means in a pressing direction, and changing a pressing force at a pressing position at the start of dressing. How to dress. 3. A dressing method for a spot welding electrode according to claim 2, wherein said dressing means is supported by a spring so as to be able to move forward and backward. 4. The method according to claim 2, wherein the pressing position is changed by a gun change.