JP2995646B2 - Welding gun arm and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a welding gun arm used for a welding gun and a method for manufacturing the same.

[0002]

2. Description of the Related Art Heretofore, as a welding gun arm, an arm body formed of an aluminum alloy is known.

[0003]

In resistance spot welding of a work, a part of the melted work, which is located between the electrodes, is so-called scatter or spatter (hereinafter, collectively referred to as spatter) when welding is conducted. ) And fly around.
Part of the spatter adheres to the gun arm. When the gun arm is simply made of an aluminum alloy, the spatter may partially dissolve and adhere to the outer surface of the gun arm, and the spatter flies one after another and deposits thereon. Therefore, it is necessary to remove spatters deposited on the gun arm from time to time, and since a part of the attached spatters melts into the outer surface of the gun arm, it takes time to remove the spatters. Is declining.

When the sputter deposited on the gun arm is observed with a microscope, a massive sputter b adheres to the gun arm a as shown in FIG.
Adhered to form a sputter-deposited layer.

[0005] Sputter b is a relatively large particle when flying to the surface of the gun arm as a sputter, and has a temperature of 1200.
° C, it adheres to the gun arm surface in a lump,
Some sputters melt the gun arm surface and have strong adhesion. In addition, it is considered that the sputter c was relatively small particles and scattered from the work, and when a part of the spatter c flew to the gun arm, it was quenched in the air and changed into a dendritic shape, and attached to the surface of the gun arm. As described above, there are at least the two types of spatters described above, and if the sputters are neglected by depositing these spatters, finally, the members of the welding gun to be insulated against the gun arm may be touched. , Causing a leakage of welding current. SUMMARY OF THE INVENTION In view of the above, an object of the present invention is to provide a welding gun arm and a method of manufacturing the same in which spatter can be easily removed and spatter deposition can be suppressed as much as possible.

[0006]

In order to achieve the above object,
The present invention relates to a welding gun arm, comprising: an anodic oxide film formed on a surface of an aluminum alloy arm body; and a fine powder of a magnetic material provided on a surface or a porous layer portion of the film. Features. A method of manufacturing a welding gun arm of the present invention forms an arm body of the welding gun arm in aluminum alloy, after forming an anodized skin layer on the surface of the arm body, it was mixed with fine powder of the magnetic material dispersion The film is subjected to a sealing treatment using a liquid.

[0007]

[Function] When an anodic oxide film is formed on an aluminum alloy arm body, heat resistance is improved. That is, the melting point of the anodic oxide film is as high as about 2100 ° C., while the temperature of the flying sputter is about 1200 ° C. at the highest, so that the sputter does not melt into the anodic oxide film. Further, since the anodic oxide film has a high insulating property, even if sputter is deposited, the sputter deposited layer and the arm main body are electrically insulated, and no current leak occurs.

However, since various adverse effects other than current leakage occur when sputters are deposited, it is necessary to remove the sputters when they are deposited, and it is necessary to further suppress sputter deposition. desired. Here, as shown in FIG. 3, dendritic spatter c, which is originally difficult to adhere, adheres to the gun arm, and further, sputter adheres and grows in a direction perpendicular to the gun arm. This phenomenon is considered to be due to the fact that a flying sputter is magnetized by a magnetic field generated around the gun arm by a current supplied to the gun arm, and adheres by interaction with the magnetic field. That is, the sputter itself is magnetized by crossing the magnetic field, advances near the surface of the gun arm where the magnetic field is strong, adheres to the surface of the gun arm so as to be attracted, and eventually deposits. Therefore, if the magnetic field around the gun arm generated by the current supplied to the gun arm is cut off, the flying spatter will not be magnetized, and the spatter adhered by the magnetization will be eliminated.

According to the present invention, since the surface of the anodic oxide film or the porous layer is provided with a magnetic material, the surface of the gun arm becomes a magnetic layer insulated from the arm body by the anodic oxide film. The magnetic flux generated around the arm body sometimes concentrates on this magnetic layer, and the magnetic field around the gun arm is weakened, so that the adhesion due to the magnetization of sputter is suppressed.

[0010] As described above, melting of spatter and adhesion due to magnetization are suppressed, and current leakage is prevented, so that it is not necessary to frequently remove spatter, and the work of removing spatter can be performed in a short time. And the operation rate of the welding gun is greatly improved.

[0011]

FIG. 1 shows a resistance spot welding gun, in which electrodes 1a and 2a are attached to tips of a pair of gun arms 1 and 2 and a work W is sandwiched between the electrodes 1a and 2a. , 2 to perform resistance spot welding of the work W.

Each of the gun arms 1 and 2 is shown in FIG.
As shown in (d), made of aluminum alloy, for example, A6061P
An anodic oxide film 11 was formed on the surface of an arm body 10 made of -T6.

The anodic oxide film 11 is formed by performing an electrolytic treatment in an electrolytic solution containing sulfuric acid or oxalic acid using the arm body 10 as an anode, and has a porous layer portion 11b outside the barrier layer 11a.

In this embodiment, the anodic oxide film 11
Is performed using a treatment liquid in which a magnetic material is mixed and dispersed. In the embodiment shown in FIG. 2A, the magnetic material 12 is applied to the surface of the anodic oxide film 11 and the porous layer portion 11b.
a. As the magnetic material 12a,
γ-Fe ₂ O ₃ is preferable, and a sealing treatment is performed by coating or dipping using a dispersion of a magnetic material obtained by mixing and dispersing γ-Fe ₂ O ₃ fine powder. In the illustrated example, a dispersion containing the resin 13 was used, but γ-F
fine powder of e ₂ O ₃ may be used which was allowed to mix dispersed.

In the embodiment shown in FIG. 2B, the surface of the anodic oxide film 11 is provided with a magnetic material 12b. The magnetic material 12b is a fine powder but has relatively large particles, and does not or hardly enter the pores of the porous layer portion 11b, and may be Fe ₃ O ₄ , Co, Fe, FeO, Cr.
O _{2 and the} like. Sealing treatment is performed using the same dispersion liquid as above mixed with Fe ₃ O ₄ and the like.

In the embodiment shown in FIG. 2 (c), the surface of the anodic oxide film 11 is subjected to a hydration sealing treatment. In the treatment, particles made of γ-Fe ₂ O ₃ or the like are used. An appropriate amount, preferably 3 to 12% by weight, of the fine powder of the small magnetic material 12a is mixed with an aqueous solution as a dispersion. Thereby, the anodic oxide film 1
The first porous layer portion 11b contains the magnetic material 12a,
It will be sealed.

[0017] In the embodiment shown in FIG. 2 (d), which was subjected to the same hydration sealing treatment and FIG 2 (c) on the surface of the anodized film 11, during the process, Fe ₃ O ₄ , Co, Fe, F
eO, relatively particles large magnetic material consisting of CrO ₂ etc. 1
An appropriate amount, preferably 3 to 12% by weight, of the fine powder of 2b is mixed. Thereby, the porous layer portion 11b of the anodic oxide film 11 is sealed, while the fine powder of the magnetic material 12b hydrates and swells together with the hydrated swell of the porous layer portion 11b of the anodic oxide film 11, and legs, during sealing, enter the remaining hole, in addition to being bound to the surface of the anodized film 11 by the anchoring effect, chemical binding, the (e.g. Fe, Al ₂ O ₃ +
Fe + H ₂ O → FeAl ₂ O ₄ + H ₂ ↑)
1 on the surface.

In the above embodiment, the material 12a having a small particle size and the material 12b having a large particle size are selectively used as the magnetic material. However, a mixture of these materials may be used for the sealing treatment. Also, the type of the sealing treatment is not limited to the above-described embodiment, but may be an electrochemical method in addition to a chemical method.

According to the above configuration, each of the gun arms 1, 2
The outermost layer becomes a magnetic layer, and the magnetic flux generated by energizing the gun arms 1 and 2 concentrates on this magnetic layer, and the space around the gun arms 1 and 2 is magnetically shielded and Weakens the magnetic field. Therefore, the spatters flying to the gun arms 1 and 2 are less likely to be magnetized, and the sputter deposition due to the magnetic attraction is suppressed.

Further, as described in the above operation, since the anodic oxide film 11 has a high melting point, the sputter solidifies without dissolving into the anodic oxide film 11, and the anodic oxide film 11 causes the sputter to solidify with the gun body 10. Since the insulating layer is electrically insulated from the deposited layer, current leakage does not occur even when the sputtered layer contacts another member.

Incidentally, even if the resin 13 is used in the above embodiment, since the magnetic materials 12a and 12b block the incoming spatter, a problem such as melting of spatter does not occur.

The anodic oxide film including the magnetic material may be formed on the entire gun arm. However, current leakage is likely to occur at a location where a problem is caused by the deposition of sputter, for example, a joint portion with the arm holder or an insulating portion. It may be formed partially at the location or at the electrode mounting portion at the tip of the arm that hinders electrode replacement.

[0023]

As is apparent from the above description, according to the present invention, the operation for removing the spatter can be performed in a short time and the frequency of the operation for removing the spatter can be reduced. Can be greatly improved.

[Brief description of the drawings]

FIG. 1 is a side view of a main part of a welding gun having a gun arm of the present invention.

FIGS. 2A to 2D are schematic cross-sectional views of the outer surface of a gun arm showing first to fourth embodiments of the present invention.

FIG. 3 is a diagram showing a conventional sputter deposition state on a gun arm.

[Explanation of symbols]

 1, 2 Gun arm, 10 Arm body 11 Anodized film, 11b Porous layer part 12a, 12b Magnetic material

Continuation of front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B23K 11/00-11/36 330

Claims (2)

(57) [Claims] 1. A welding gun arm comprising: an anodic oxide film formed on a surface of an aluminum alloy arm body;
A gun arm for welding, wherein a fine powder of a magnetic material is provided on a surface or a porous layer portion of the coating. 2. A form arm body of welding gun arm of aluminum alloy, sealed after the formation of the anodic oxide skin layer on the surface of the arm body, the said coating using a dispersion obtained by mixing a fine powder of a magnetic material A method for manufacturing a welding gun arm, characterized by performing a hole treatment.