JP2001232480A - Method and device for confirming axial center misalignment of spot welding gun electrode - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a confirming method and a confirming device capable of correctly judging whether spot welding is continued or not by surely confirming by visual observation the degree of relative misalignment between axial centers of a first electrode and a second electrode which face each other. SOLUTION: An axial center misalignment confirming device which has at one end a cylindrical lower recessed part (a first recessed part) 11 capable of fitting around the lower electrode (the first electrode) 60 and which has at the other end a cylindrical upper recessed part (a second recessed part) 12 coaxial with the lower recessed part 11 and having a radius larger by the maximum allowable dimension of axial center misalignment than the radius of the upper electrode (the second electrode) 70, is used. After the lower electrode 60 is covered by the lower recessed part 11 and the upper recessed part 12 is positioned coaxially with the lower electrode 60, the upper electrode 70 is approached to the lower electrode 60, and whether relative misalignment of axial centers of both electrodes is within allowable range or not is confirmed by whether the upper electrode 70 interferes with the peripheral wall of the upper recessed part 12 or not.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for confirming a deviation of an axis of a tip electrode of a spot welding gun, and more particularly, to a method of visually confirming a gap between the tip electrode and a second electrode by attaching to a first electrode. The present invention relates to a method and an apparatus capable of confirming the relative displacement of the axial centers of both electrodes only by using the method.

[0002]

2. Description of the Related Art First, the necessity of confirming the axial deviation of an electrode attached to a welding gun when performing spot welding will be described. In spot welding, generally, two or more steel plates are sandwiched between electrodes made of copper, and a large current is applied in a state where the steel plates are pressed by the electrodes, and the steel plates are melt-bonded by generated Joule heat. That is, as shown in FIG. 5, the steel plates 81 and 82 pressed between the lower electrode 60 and the upper electrode 70 are melted by Joule heat generated by a large current flowing through the lower electrode 60 and the upper electrode 70. A portion called a nugget 90 is generated, and the nugget 90 is solidified and the two steel plates 81 and 82 are joined.

Meanwhile, between the lower electrode 60 and upper electrode 70 attached to the welding gun, since the pressure of the sides of the steel plate ^{81,82 200Kg / cm 2 ~500Kg / cm} 2 is loaded, stationery spot welding Machine and C-type spot welding gun, as well as X-type spot welding gun,
In order to maximize the pressing force, the lower electrode 6 is used during welding.
0 and the axis of the upper electrode 70 are set so as to coincide with each other, but after welding a large number of hit points, buckling of both electrode shafts due to repetition of high pressing force and wear of the movable portion of the welding gun cause A relative displacement between the lower electrode 60 and the upper electrode 70 (hereinafter, referred to as “axial displacement”) occurs. In particular,
As shown in FIG. 6, when spot-welding the ends of the steel plates 81 and 82, such as the flanges 83, the lower electrode 60 and the upper electrode 70 are pressurized in a state where the axial center is misaligned, and a large current flows. A nugget 90 is formed near the end of the flange 83, and the nugget 90, whose volume has increased due to the melting of the steel plates 81 and 82, can not withstand the pressing force and explodes from the plate edge,
Sputtering 100 occurs. When the nugget 90 is solidified with the melted portions of the steel plates 81 and 82 reduced by the explosion as spatters 100, the bonding strength of the steel plates 81 and 82 is reduced, that is, the welding strength is reduced. Even if the nugget 90 does not explode and solidifies as it is, the nugget 90 is displaced by the axial center of the lower electrode 60 and the upper electrode 70.
Since the area where the lower electrode 60 and the upper electrode 70 face each other is reduced, the lower electrode 60 and the upper electrode 70 are formed in a small area such as a substantially semicircular shape.
Sufficient welding strength cannot be obtained as compared with a normally circular nugget with no axial deviation.

Also, the nugget 90 explodes and spatters 1
00, and the solidified solid remains as a pointed burr at the welding location. If the burrs remain, they may be injured when workers or consumers touch the burrs. Therefore, after the spot welding operation, a finishing operation for removing the burrs with a grinder or the like is necessary. As described above, if the axis of the electrode of the spot welding gun is misaligned, the above-described problem occurs.Therefore, in the welding process, the allowable range of the axis misalignment is determined. It is necessary to find out and perform special management so that the axial misalignment of the electrode can be corrected before the above-mentioned problem occurs.

[0005] Conventionally, as a method for confirming the axial center deviation, a so-called visual method in which a lower electrode and an upper electrode are brought into contact with each other and observed from the periphery of the side surface has been used in many cases, but this method is simple and quick. Although there is an advantage that can be obtained, judgments vary from observer to observer due to sensitivity evaluation, and accuracy is lacking.

As a countermeasure against this, an attempt has been made to confirm the axial deviation using a tool 40 as shown in FIG. That is, the tool 40 is provided with the electrodes 6 having the upper and lower inner diameters.
The divided cylinders 41 and 42 obtained by dividing a copper or steel pipe having substantially the same outer diameter as 0 and 70 into two in the axial direction are attached to a clip 50 used to sandwich paper or the like by a spring force. , 42, the upper and lower electrodes 60 in contact with each other,
70 is sandwiched. Then, the upper and lower electrodes 6
If the axes 0 and 70 are on the same line, that is, if there is no misalignment of the axes, the dividing lines of the divided cylinders 41 and 42 appear almost in close contact. You can decide to do it. However, when the axial center shift occurs, as shown in FIG. 8, the dividing lines of the divided cylinders 41 and 42 are separated from each other, and a gap is opened, that is, a gap β appears. That is, for example, when the axis of the upper electrode 70 is displaced or inclined with respect to the axis of the lower electrode 60, the divided cylinders 41 and 42 cannot sandwich the upper electrode 70 well and open slightly. Stop in a state where Based on the degree of the opening, it is determined whether or not the degree of the axial center deviation is within an allowable range, and it is determined whether or not to continue the spot welding operation.

[0007]

However, in such a conventional tool 40, the degree of axial center deviation can be quantified by measuring the gap β of the dividing line with a scale or the like, but FIG. As shown in (B), it is necessary to perform the above-described measurement while searching for the direction of the maximum axial center deviation. That is, when the upper and lower electrodes 60 and 70 are sandwiched by the tool 40 several times,
As shown in FIG. 8A, a position indicating the maximum axial deviation of the upper and lower electrodes 60 and 70 is searched, and the tool 40 is held with the upper and lower electrodes 60 and 70 sandwiched with respect to the axis J in the plan view at the position.
8B when the axis K perpendicular to the opening / closing direction is held at approximately 90 °, and as shown in FIG.
From the state shown in (A), the tool 40 is rotated at least 90 ° to compare the gap β when the axis K is aligned with the axis J, and the larger gap β is measured and converted into the amount of axial misalignment. I do. As described above, the tool 40 includes the upper and lower electrodes 60 and 7.
It is necessary to specify the maximum position of the amount of axial misalignment when 0 is interposed, so that it takes time to search for and measure the measurement position, and it is difficult to frequently measure during the welding operation.

In order to solve the above-mentioned problems, the present invention provides a method and a device for accurately determining whether or not to continue welding by enabling the degree of axial misalignment to be reliably confirmed visually. The purpose is to provide.

[0009]

SUMMARY OF THE INVENTION According to the present invention, there is provided a method for confirming a displacement of an axis of a spot welding gun electrode, the spot welding gun being adapted to spot weld a workpiece between a first electrode and a second electrode facing each other. A method for confirming whether or not the relative displacement between the axes of the two electrodes is within an allowable range, wherein one end has a radius larger than the radius of the second electrode by a maximum allowable dimension of the displacement. A device having a cylindrical concave portion, and having, at the other end, a positioning portion capable of positioning the concave portion on the first electrode so that the axis of the concave portion coincides with the axis of the first electrode. Positioning the recess in the first electrode, bringing the second electrode closer to the first electrode,
It is characterized in that whether or not the relative displacement between the two electrodes is within an allowable range is determined by whether or not the second electrode interferes with the peripheral wall of the concave portion. Therefore, the cylindrical concave portion is positioned on the first electrode, the second electrode is brought close to the concave portion, and it is visually determined whether or not the inner peripheral wall of the concave portion and the outer peripheral surface of the second electrode interfere with each other. Anyone can judge the degree of axial misalignment by confirming it, so anyone can make objective decisions in a short time, easily check the axial misalignment between spot weldings, and improve the actual welding time and welding quality. Can be achieved.

Further, the apparatus for confirming the axial center deviation of a spot welding gun electrode according to the present invention is characterized in that the two electrodes of the spot welding gun perform spot welding by sandwiching a work between a first electrode and a second electrode facing each other. A device for confirming whether or not the relative displacement of the axes of the shafts is within an allowable range.
A first concave portion having a cylindrical shape that can be fitted to the first electrode, and a maximum allowable dimension of the deviation at the other end, which is concentric with the first concave portion and is larger than a radius of the second electrode; It is characterized by having a cylindrical second concave portion having a radius as large as possible. Therefore, when confirming the axial deviation of the spot welding gun electrode, by inserting the first electrode into the first concave portion, the axial position of the cylindrical second concave portion continuous with the first electrode is set to the first concave portion. It is determined as the same position as the axis of the electrode, and by bringing the second electrode closer to the second recess, the second wall is formed on the peripheral wall of the cylindrical second recess having a radius larger by the maximum allowable dimension of the axial deviation. Only by visually checking whether or not the electrodes interfere with each other, it is possible to reliably confirm the presence or absence of the axial center deviation in a short time.

Further, in the apparatus for confirming an axial center deviation of a spot welding gun electrode according to the present invention, the first concave portion and the second concave portion are provided back to back to each other, and the center cross section is substantially H.
It is characterized by being formed in a mold. Therefore, when the first electrode is inserted into the first recess, the upper end of the first electrode abuts on the bottom, that is, the ceiling, of the first recess, and positioning can be performed.
Further, since the center cross section is a substantially H-shaped cross section, the first concave portion and the second concave portion can be formed coaxially with high precision by machining.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of a method and an apparatus for confirming an axial deviation of a spot welding gun electrode according to the present invention will be described with reference to the drawings. Here, FIG. 1 is a schematic view of a plane in which the apparatus for confirming the axial center deviation of the spot welding gun electrode according to the present embodiment is mounted, (A) is a plane without the axial center deviation, and (B) is a longitudinal section thereof. FIG. FIG.
FIG. 3A shows a state in which the axial center deviation is within an allowable range, FIG. 3A is a schematic view of the plane, and FIG. 3B is a longitudinal sectional view thereof. 3A and 3B show a state in which the axial center deviation is out of the allowable range, FIG. 3A is a schematic plan view, and FIG. 3B is a longitudinal sectional view. FIG. 4 is a perspective view of the device for confirming the axial center deviation of the spot welding gun electrode according to the present embodiment.

(Structure) The apparatus for confirming the axial center deviation of the spot welding gun electrode according to the present embodiment (hereinafter referred to as “axial center deviation gauge 1”)
0 ". ) Will be described. As shown in FIGS. 1 to 4, the axial misalignment gauge 10 includes a lower chip 6 having a lower electrode 60 (corresponding to a “first electrode”).
1 is formed with a cylindrical lower concave portion 11 (corresponding to the "positioning portion" of claim 1 and the "first concave portion" of claim 2) which is slidably mounted, and is coaxial with the lower concave portion 11 above. An upper concave portion 12 (corresponding to a “second concave portion” in claim 2) is formed in which the bottom portion 13 is shared with the ceiling portion of the lower concave portion 11.

More specifically, the lower concave portion 11 is opened downward, and the inner peripheral wall 111 is formed to have an inner diameter substantially equal to the outer diameter of the lower chip 61 of the lower electrode 60. Therefore, when the lower concave portion 11 is mounted so as to cover the lower chip 61, the lower concave portion 61 slides precisely, and the upper end of the lower chip 61 contacts the lower surface of the bottom portion 13 of the upper concave portion 12, and the lower concave portion 11
Is positioned and held so that the axis of the lower tip 61 coincides with the axis of the lower chip 61.

The upper concave portion 12 is opened to the upper side with the same axis as the lower concave portion 11, and the inner peripheral wall 121 is formed on the upper electrode 70 (corresponding to the "second electrode" in the claims) for checking the amount of axial deviation. The upper tip 71 is formed to have an inner diameter larger than the outer dimension of the upper tip 71 by the maximum allowable dimension of the axial center deviation in radius. Specifically, in the case of the present embodiment, since the outer diameter of both the lower chip 61 and the upper chip 71 is 16φ, the inner diameter of the lower concave portion 11 is formed to be 16.2φ, and the upper concave portion 1 is formed.
The inner diameter of No. 2 was formed to be 20φ because the maximum allowable dimension σ of the axial center deviation was 2 mm. In accordance with the specifications of the upper and lower electrodes 60 and 70, for example, an axial misalignment gauge 1 for 13φ and 19φ
0 may be prepared.

In the present embodiment, the axial misalignment gauge 1
Although 0 is an H-shaped cross section, the bottom portion 13 only needs to be in contact with the top portion of the lower chip 61 when the lower chip 61 is inserted into the lower concave portion 11 so that the axial center misalignment gauge 10 can be positioned with respect to the lower chip 61. Therefore, the bottom 13 may have a projection-like cross section with a hole.

Therefore, the apparatus 10 for confirming the axial misalignment of the spot welding gun electrode according to the present embodiment merely covers the lower tip 61,
It is possible to perform positioning.

(Operation) Next, a description will be given of a method for confirming the axial deviation of the spot welding gun electrode using the apparatus for confirming the axial deviation of the spot welding gun electrode. First, the upper and lower electrodes 60 and 70 of the spot welding gun are kept apart and open. Then, as shown in FIG. 1 to FIG.
1 is covered with the lower concave portion 11 of the axial misalignment gauge 10, and is inserted until the top of the lower chip 61 comes into contact with the lower surface of the bottom portion 13 of the axial misalignment gauge 10, that is, the ceiling of the lower concave portion 11 and stops. Then, the axis misalignment gauge 10 is positioned and held on the lower chip 61 such that the upper concave portion 12 coincides with the axis of the lower electrode 60. While maintaining the state where the axial misalignment gauge 10 is positioned on the lower tip 61 in this manner, the welding gun is gradually operated to bring the upper electrode 70 close to the opening of the upper concave portion 12 of the axial misalignment gauge 10.

When the upper electrode 70 is gradually approached to the opening of the upper concave portion 12 of the axial misalignment gauge 10, the upper tip 71 of the upper electrode 70 and the peripheral walls of the upper concave portion 12 and the peripheral wall of the upper concave portion 12 depend on the degree of occurrence of the axial misalignment. The relationship with the openings is as shown in FIGS. That is, if the axial center of the upper electrode 70 with respect to the lower electrode 60 is not present or is within the allowable range, the state is as shown in FIG. 1 or FIG.

FIG. 1 shows a case where there is no axial deviation. When there is no axial deviation, the upper electrode 70 enters the upper concave portion 12 of the axial deviation gauge 10, and the outer peripheral surface of the upper chip 71 is axially shifted. It has a constant gap δ (same dimension as the maximum allowable dimension σ, 2 mm in this embodiment) with the inner peripheral wall 121 of the upper concave portion 12 of the displacement gauge 10. This gap δ is constant over the entire outer peripheral surface of the upper chip 71 as shown in FIG. The operator may visually confirm that the gap δ exists. (It does not matter whether it is constant or not.)

FIG. 2 shows a case where there is an axial center deviation but within an allowable range. That is, when there is an axial deviation within the allowable range, the gap δ is within the range of 0 mm to the maximum allowable dimension σ in the narrower direction. When the axial deviation is the largest, the gap δ is 0 mm as shown in FIG. The outer peripheral surface of the upper chip 71 is housed in the upper concave portion 12 while being in contact with the inner peripheral wall 121 of the upper concave portion 12 of the axial misalignment gauge 10. Therefore, as shown in FIG. 2A, the upper tip 71 is eccentric with respect to the upper concave portion 12 of the axial misalignment gauge 10. The operator may visually confirm that the upper chip 71 is housed in the upper recess 12. Up to this point, it is determined that the upper electrode 70 does not interfere with the inner peripheral wall 121 of the upper recess 12.

Next, the upper electrode 70 with respect to the lower electrode 60
In the case where the axial center deviation is outside the allowable range, the result is as shown in FIG. That is, when the upper electrode 70 is gradually approached to the opening of the upper concave portion 12 of the axial misalignment gauge 10, the upper electrode 70 is in contact with the upper concave portion 12 in which the inner diameter of the inner peripheral wall 121 is formed within the allowable range of the axial misalignment. The tip of the upper chip 71 of the upper electrode 70 contacts the opening corner 122 of the upper recess 12 and interferes therewith. The operator can check that the upper chip 71 is
It may be visually confirmed that the light beam interferes with the opening angle portion 122.

As described above, the operator can determine whether the upper tip 71 of the upper electrode 70 has entered the opening of the upper recess 12 of the axial misalignment gauge 10 and the gap δ exists, or the upper tip 71 has What is necessary is just to check visually whether it can enter by interfering with the opening corner 122 of the recess 12. Then, based on the results confirmed above, it is determined whether or not the axis deviation is within the allowable range, to determine whether to continue or interrupt the spot welding work, and to determine that the axis deviation is out of the allowable range. If so, take corrective action for the misalignment.

As described above, according to the method for confirming the axial displacement of the spot welding gun electrode using the apparatus for confirming the axial displacement of the spot welding gun electrode according to the present embodiment, one end can be fitted to the lower electrode 60. A cylindrical upper concave portion 12 is formed at the other end, concentric with the lower concave portion 11, and having a radius larger than the maximum allowable dimension of the axial center deviation of the upper electrode 70. The lower recess 11 is positioned over the lower chip 61 of the lower electrode 60 for positioning.
0 gradually decreases, the upper electrode 70
When the axial center deviation of the upper electrode 70 with respect to the lower electrode 60 is within an allowable range, the upper electrode 70 enters the upper concave portion 12, and the axis thereof exceeds the maximum allowable dimension. If the misalignment occurs, the upper electrode 70 abuts on the opening corner 122 of the upper concave portion 12 and interferes with the entry, so that the operator can visually confirm this phenomenon and easily determine that the axial misalignment is within the allowable range. Can be found and whether welding can be continued or not can be determined. Therefore, it is not necessary to stop the welding work for a long time, and the actual working time of the welding can be enhanced.

It should be noted that the present invention is not limited to the above embodiment, and various changes can be made without departing from the spirit of the present invention. For example, in the above embodiment,
Although the axial misalignment gauge 10 has been described as being formed in a cylindrical shape, the invention is not limited to this, and a polygon such as a quadrangle as shown in FIG. 4B is also possible. However, it is desirable that the ceiling of the lower concave portion 11 is shared with the bottom portion 13 of the upper concave portion 12 and that the outer wall portion 14 is formed so as to have a substantially H-shaped cross section parallel to the axis.

[0026]

According to the present invention, at one end, a cylindrical concave portion having a radius larger than the radius of the second electrode by the maximum allowable deviation is provided, and at the other end, the axial center of the concave portion is the first electrode. After positioning the concave portion on the first electrode using a device having a positioning portion capable of positioning the concave portion on the first electrode so as to coincide with the axis of the first electrode, the second electrode is connected to the first electrode. To determine whether or not the relative displacement between the two electrodes is within an allowable range by checking whether the second electrode interferes with the peripheral wall of the recess. Since the method for confirming the deviation is employed, the situation of the axial center deviation of the two electrodes can be visually confirmed in a short time, and it is possible to judge whether or not to continue the welding, and it is possible to improve the actual working time of the spot welding operation. Further, the present invention has, at one end, a cylindrical first concave portion that can be fitted to the first electrode, and at the other end, concentric with the first concave portion, and the second electrode. Of a cylindrical shape having a radius larger than the radius of
Since the axial center deviation of the spot welding gun electrode is characterized by having the concave portion, the axial center of the first electrode is displayed on the second electrode side by the second concave portion.
By simply bringing the second electrode closer to the concave portion, it was possible to detect the presence / absence of axial misalignment.

[Brief description of the drawings]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view of a plane in which an apparatus for confirming an axial center deviation of a spot welding gun electrode according to an embodiment of the present invention is mounted, (A) is a state where there is no axial center deviation, and (B) is a plan view. FIG.

FIG. 2 shows a state in which an apparatus for confirming an axial center deviation of a spot welding gun electrode according to an embodiment of the present invention is installed, and the axial center deviation is within an allowable range, and FIG. (B) is a longitudinal sectional view thereof.

3A and 3B show a state in which the axial center deviation is out of an allowable range, FIG. 3A is a schematic view of a plane thereof, and FIG. 3B is a longitudinal sectional view thereof.

FIG. 4 is a perspective view of two modes of an apparatus for confirming a center deviation of a spot welding gun electrode according to the present embodiment.

FIG. 5 is a sectional view of a portion to be welded by general spot welding.

FIG. 6 is a cross-sectional view when a plate end portion of a general flange is spot-welded with an axial center misalignment.

FIG. 7 is a perspective view of an example of a conventional tool for measuring an axial misalignment.

8A and 8B are cross-sectional views when searching for a gap generated due to an axial center deviation using the tool shown in FIG. 7, wherein FIG. 8A shows a case where the gap is maximum, and FIG. 8B shows a case where it is minimum.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Axis misalignment gauge 11 Lower concave part (first concave part) 12 Upper concave part (second concave part) 122 Opening corner part 40 Tool 50 Clip 60 Lower electrode (first electrode) 61 Lower chip 70 Upper electrode (second electrode) ) 71 Upper chip

Claims (3)

[Claims] 1. A spot welding gun for spot welding a workpiece between a first electrode and a second electrode facing each other.
A method for confirming whether or not a relative deviation between the axes of said two electrodes is within an allowable range. A cylinder having a radius larger than a radius of said second electrode by a maximum allowable dimension of said deviation at one end. A device having a positioning portion capable of positioning the concave portion on the first electrode so that the concave portion has the same shape as the axis of the first electrode at the other end. After positioning the concave portion on the first electrode, the second electrode is brought closer to the first electrode, and the relative position of the two electrodes is determined based on whether the second electrode interferes with the peripheral wall of the concave portion. A method for checking the center deviation of the spot welding gun electrode, which checks whether the typical deviation is within the allowable range. 2. A spot welding gun for spot welding a work between a first electrode and a second electrode facing each other.
An apparatus for confirming whether or not the relative displacement between the axes of the two electrodes is within an allowable range, comprising, at one end, a cylindrical first concave portion that can be fitted to the first electrode. At the other end, a spot-welded cylindrical portion having a radius concentric with the first recess and having a radius larger than a radius of the second electrode by a maximum allowable dimension of the deviation. A device for checking the axis center deviation of the gun electrode. 3. The apparatus according to claim 2, wherein the first concave portion and the second concave portion are provided back-to-back with each other, and have a substantially H-shaped central cross section. A device for confirming the axial misalignment of a spot welding gun electrode.