JPS6016876B2 - Reinforced insulation coating welding gun and its manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a movable spot welding gun used in a so-called resistance welding device for welding several thin iron plate members (mainly pressed products) when assembling an automobile body or the like. (hereinafter simply referred to as a welding gun), and more specifically, it relates to a welding gun equipped with a welding gun arm having extremely excellent performance, and a method for manufacturing the same.

Equipment such as welding electrodes and welding guns used in resistance welding equipment should not come into contact with the workpiece or the positioning device used to fix it during welding operations, causing an external short circuit. It is well known that avoidance of surprise can lead to serious defects in the performance of the welded part, and that prevention of this is an important issue.

A common solution to this problem is to insulate the part. However, no satisfactory insulation treatment has been found so far. Let's talk about conventional insulation processing.

You can form a thick coating layer on the necessary parts of the welding gun, such as the arm, using resin such as polyamide, wrap ordinary insulating tape around the necessary parts, or apply nickel plating on top of the resin coating. In addition, we have seen products that have improved impact resistance and abrasion resistance, and even products that use a thermal spraying device to spray ceramic onto the surface of necessary parts to form a coating. However, all of these have advantages and disadvantages,
There is no material that has all the characteristics of insulation, workability, wear resistance, etc., and attempts have been made to improve insulation even if workability is reduced to some extent, but they are expensive and have little practical use. There was a momme point. To explain about welding equipment, especially welding guns, from the perspective of actual work, for example, when assembling a car body, we often need to weld the body parts required. Before welding work, it is necessary to insert one of the fin poles deep inside the part through the closed part of the part and hold it in a certain position (
Figure 1).

At this time, the positive electrode comes into contact with the sharp ridge of the inserted part, causing a short circuit, but the above-mentioned ordinary insulation process is an attempt to prevent this short circuit. However, these insulation treatments have thick coatings and poor abrasion resistance. For example, after a few uses, the insulation tape, resin coating, and other insulating parts wear out, causing short circuits, requiring parts to be replaced, and slowing down work. The reality is that they are forced to do so. Furthermore, since it is necessary to re-insulate the part, the effort and cost cannot be ignored. The present invention has an extremely strong resistance to being scratched and damaged even when the so-called welding gun comes into contact with the sharp ridges of the parts to be welded, and is superior to the conventional products described above. This is a fundamental improvement on its shortcomings. An example of the present invention will be explained with reference to the drawings. Fig. 1 shows a welding gun part which is a main part of a welding rhombus, and 1 is a welding gun arm inserted into the interior 4 of a part 2 to be welded through a hole 3. , 5 is an electrode pressurizing rod, and 6 is a part to be welded.

7 and 8 are electrode tips attached to the tips of arms 1 and 2, and 9 indicates a welding point.

FIG. 2 shows a sectional view taken along line AA of the welding gun arm 1, and a cooling water path c 10 is an insulating layer on the surface of the arm 1. Now, regarding the welding gun arm 1, which is an important part of the present invention, in Figs. 2 and 3, reference numeral 11 is an arm base mainly made of copper alloy. It has a resin coating 12 or a ceramic layer formed by thermal spraying or bonding ceramic powder, and the layer may have a thickness of about 0.2 to 0.5 mm. A thermally sprayed coating 13 of a highly ductile metal, such as zinc, is formed on this coating to a thickness of about 0.1 to 0.3 mm, and a metal with high electrical resistance, such as S, is coated on the surface.
The US-based metal spray coating 14 has a thickness of approximately 1 to 1.5 ribs, and is further impregnated with an appropriate resin such as an epoxy resin into the continuous fine pores of the metal spray coating.

The welding gun of the present invention is mainly composed of an insulating arm having such a special structure, and is completed by adding necessary parts such as electrode tips 7 and 8 to the insulating arm. Next, a method for manufacturing the welding gun of the present invention will be described. In Fig. 3, reference numeral 11 denotes a welding gun arm base made of a steel alloy. 0.2～
A thin skin 12 of about 0.5 tuna is formed. After the surface of this resin film is also roughened, a thin skin 13 with a thickness of about 0.1 to 0.3 ribs is formed on the upper surface using a method of metal spraying with highly ductile zinc. A film 14 of approximately 1 to 1.5 side is formed using a metal having a high viscosity, such as a SUS metal, by means of metal blasting. This metal film 14 has fine continuous pores 15, and a suitable resin such as epoxy resin is impregnated into the fine pores. The means for impregnating the resin is to use a vacuum tank bag.The resin solution is poured into the tank, and after the arm in which the film has been formed is immersed, the air in the tank is pumped out using a vacuum pump (not shown). 2)
When the pressure is reduced to about skin/mHg, the air in the fine pores of the metal layer 14 is also degassed through the resin liquid. After carefully confirming this reduced pressure state, when the pressure is returned to atmospheric pressure, a strong force of approximately 100 mph acts, causing the resin liquid to enter and fill the microscopic pores.

When this impregnated resin is hardened, for example, in the case of a thermosetting resin, it is heated in a furnace to complete the electrically insulating welding gun arm. The result of this integral bonding of metal and resin is that the abrasion resistance of the metal particles and the impact resistance of the bonding of the resin work together effectively, resulting in an arc with excellent physical properties.
It becomes a problem.

As a result of experiments, it was found to be 5 to 6 times stronger than conventional products. As already mentioned, it is also possible to thermally spray ceramic to form a ceramic film on the 0.2 to 0.5 side instead of the initial resin coating, and this also results in a good effect. A good effect can also be obtained by coating with carbon cloth or glass cloth and then coating with resin.

The welding gun of the present invention has a welding gun arm that exhibits excellent resistance to short circuits caused by contact with parts to be welded as described above, and this can be understood from the structure in which a metal film with high electrical resistance is bonded with resin. As shown in the figure, the impact resistance and abrasion resistance are improved, and there is no occurrence of breakage or damage, resulting in a dramatic increase in the service life.

Since the price is low, it can be said that it has an absolutely wonderful substance. The conventional method for achieving this effect is to apply a resin coating on the arm base 11, then apply an electric current to it, and then nickel plate the surface. There are things that increase strength.

Such a method takes a long time and is costly; in other words, because the shape of the arm is complex, it is technically difficult to apply nickel plating to a certain thickness around the arm. It is well known that this does not improve productivity and increases costs. Generally, thermally sprayed metal coatings have approximately 3 to 4% continuous micropores, and impregnation with resin liquid can be easily achieved in a vacuum tank, so mass production is possible. The cost is also lower.

The welding gun of the present invention is completely unprecedented in terms of performance and cost.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing how the welding gun is used. FIG. 2 is an enlarged sectional view taken along the line A-A' in FIG. FIG. 3 is an enlarged explanatory view showing a coating on an arm portion of a welding gun according to the present invention. Description of symbols, 1... Welding gun arm, 2... Parts to be welded, 3...
Hole, 4... Inside, 5... Electrode pressure rod, 6... Parts to be welded, 7... Electrode tip, 8... Fin pole tip.
9... Welding point, 10... Cooling water passage, 11... Arm base, 12... Resin layer (first layer), 13... Zinc coating (second layer), 14... Metal coating (3rd layer), 15・
...Minor pores. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1. An electrically insulating thin film is formed on the surface of the welding gun arm, a sprayed metal layer is formed by spraying a highly ductile metal such as zinc, and a metal with high electrical resistance is coated on the upper surface of the sprayed metal layer. A reinforced insulating coating comprising an insulating welding gun arm formed by forming a sprayed layer with a thickness of about 1 to 1.5 mm and impregnating the fine pores of the sprayed layer with resin, and adding other necessary parts. Processing welding gun. 2. The reinforced insulating coating processing welding gun according to claim 1, wherein the electrically insulating thin layer is a resin or ceramic thin layer. 3 The surface of a welding gun arm made of a copper alloy is roughened, an electrically insulating thin film is formed thereon, and after the surface is roughened, a highly ductile metal such as zinc is sprayed to form a metal coating. Further, a metal layer with a thickness of about 1 to 1.5 mm is formed by spraying a metal with high electrical resistance on the upper surface, and then this film welding gun arm is placed in a vacuum tank device with a thermosetting resin solution, After deaerating the tank and discharging the air in the micropores of the metal layer, by returning the tank to normal pressure,
A method for manufacturing a welding gun for processing a reinforced insulating film, characterized in that the micropores are impregnated with a resin solution, the thus obtained reinforced insulating arm is the main body, and necessary parts are further added to complete the reinforced insulating arm. 4. The method for manufacturing a reinforced insulating coating welding gun according to claim 3, wherein the electrically insulating thin film is a resin or ceramic thin layer.