JPH05154667A - Spot welding method - Google Patents

Abstract

PURPOSE:To surely perform welding on plates having a covering layer by plating or coating. CONSTITUTION:The spot welding method is applied when the superposed surface of one plate 1 of two plates 1 and 2 such as iron plates which are superposed on each other and welded together has the electrical insulating covering layer 3 by plating or coating. A hole 4 is bored on the plate 1 having the covering layer 3 and a projection 5 is provided on the other plate 2 by a center punch, etc. These hole 4 and projection 5 are engaged with each other to hold both plates 1 and 2 between electrodes 6 and 7 and an electric current is carried thereto in a pressurized state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spot welding method for a plated or coated plate material.

[0002]

2. Description of the Related Art In spot welding, as shown in FIG. 2, two plate members 13 and 14 which are objects to be welded are provided between electrodes 11 and 12.
It is a method in which both plate members 13 and 14 are melted by resistance heat through an electric current by applying a current by sandwiching and joining.

[0003]

However, when an electrically insulating coating layer 15 formed by plating or coating is applied to the overlapping surface of either one of the plate members 13, both plate members 13, 1
No electric current flows between the four, and spot welding may not be possible or may not be performed well.

An object of the present invention is to provide a spot welding method capable of reliably welding a plate material having a coating layer.

[0005]

According to the spot welding method of the present invention, a hole is formed in a plate material having a coating layer on an overlapping surface and a projection is provided on the other plate material of two plate materials arranged to overlap each other. In this method, the holes and the projections are engaged with each other and the plate members are overlapped with each other, and the portions of the plate members on which the holes and the projections are formed are welded to each other.

[0006]

According to this welding method, the metal portion of the plate material is exposed on the inner surface of the hole formed in the plate material having the coating layer, and a current flows between this exposed portion and the protrusion of the other plate material. Therefore, spot welding can be reliably performed. Further, the plate members can be positioned relative to each other by the engagement between the holes and the protrusions.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described with reference to FIG. This spot welding method is a welding method in which one of two plate materials 1 and 2 such as iron plates to be welded on top of each other has an electrically insulating coating layer 3 formed by plating or coating on the overlapping surface of one plate material 1. Is. Coating layer 3
1 is provided with a hole 4 and the other plate 2 is provided with a hole 4
A small protrusion 5 is provided at a position corresponding to. The protrusion 5 is formed as an embossed protrusion by, for example, a center punch.

The holes 4 and the protrusions 5 are engaged with each other as shown in the figure, and the plate materials 1 and 2 are overlapped. , 7, and current is applied between both electrodes 6, 7 while applying pressure.

According to this welding method, the hole 4 is formed in the plate member 1 having the coating layer 3, so that the metal portion of the plate member 1 is exposed on the inner surface of the hole 4 and the protrusion 5 faces the exposed portion. Therefore, the metal parts of the plates 1 and 2 are in direct contact with each other or close to each other to ensure the energized state, and the current flows regardless of the coating layer 3 to perform reliable welding.

Further, since the projection 5 engages with the hole 4, the mutual positioning of the two plate members 1 and 2 is ensured. As for the cost of machining the holes 4 and the protrusions 5, if the plate materials 1 and 2 are parts made by a punch press machine or the like, it suffices to add a slight amount of machining when machining the other holes or protrusions, and the NC program is also available. Only a few additions are needed, so the cost increase is small.

In the above embodiment, the plate member 2 on the side of the protrusion 5 has no cover layer, but the case where both plate members 2 have an electrically insulating cover layer on the overlapping surface. However, since the metal portion of one plate member 1 is exposed in the hole 4, it is easier to obtain an energized state than when the hole 4 and the protrusion 5 are not formed, and welding can be performed depending on the thickness of the coating layer and the like.

[0012]

According to the spot welding method of the present invention,
Since a hole is formed in the plate member on the coated side and a protrusion that engages with the hole is provided in the other plate member, it is possible to reliably conduct electricity between the metal portion exposed on the inner surface of the hole and the protrusion. Therefore, spot welding can be reliably performed regardless of the electrically insulating coating layer. Further, there is an effect that the engagement between the hole and the protrusion can be utilized for positioning the plate members relative to each other.

[Brief description of drawings]

FIG. 1 is a sectional view showing a welding method according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a conventional welding method.

[Explanation of symbols]

1, 2 ... Plate material, 3 ... Coating layer, 4 ... Hole, 5 ... Protrusion, 6, 7
…electrode

Claims (1)

[Claims] 1. A plate member having a coating layer on an overlapping surface of two plate members arranged to overlap each other is provided with a hole, and the other plate member is provided with a protrusion, and the hole and the protrusion are engaged with each other to form a plate. A spot welding method in which plate members are overlapped with each other and the portions where the holes and the projections of both plate members are formed are welded to each other.