JP-2025099657-A5 -

Dates

Publication Date

20260508

Application Date

20231222

Description

This invention relates to a projection welding member suitable for use in a resistance welding apparatus that welds a plate assembly (workpiece to be welded) made by overlapping two steel plates by sandwiching it between two electrodes and applying pressure while applying current. Resistance welding equipment includes a table-type system where one of the two electrodes (the lower one) is fixed in a table shape, and the other (the upper one) is gun-shaped and movable up, down, left, and right. In this type of resistance welding equipment, the workpiece is sandwiched between the table-type electrode and the gun-type electrode, and welding is performed by applying current while applying pressure with the gun-type electrode. Incidentally, in resistance welding, in order to obtain a good weld, a projection-like structure called a projection is formed on one of the two steel plates (see, for example, Patent Document 1). Here, an example of projection is shown in Figures 7 and 8. In Figure 7, (a) is a side view of the steel plate 200, and (b) is a view of the steel plate 200 from the direction of arrow J. On the steel plate 200, mountain-shaped projections 201 and 202 are formed spaced apart in the longitudinal direction of the steel plate 200 (direction of arrow K). Figure 9 shows the process of joining steel plates 200 and 210. As shown in the figure, the projections 201 and 202 formed on steel plate 200 come into contact at one point during welding of steel plates 200 and 210. In this state, supplying current and applying pressure between the steel plates causes the current to concentrate at the projection locations. This melts the projections 201 and 202, and further melts across the entire contact surface between steel plates 200 and 210, joining the two steel plates together. In Figure 8, (a) is a side view of the steel plate 220, and (b) is a view of the steel plate 220 from the direction of arrow M. The steel plate 220 has V-shaped projections 221 and 222 formed on it, spaced apart in the longitudinal direction (direction of arrow N). During welding with the other steel plate 210 (see Figure 9), the tips of the projections 221 and 222 on the steel plate 220 come into contact at two points. In this state, by supplying current and applying pressure between the steel plates, the current flows concentrated at the locations where the projections are formed. This causes the projections 221 and 222 to melt, and further melting across the entire contact surface between the steel plates 220 and 210, joining the steel plates 220 and 210 together. Note that the above example showed projections applied to only one steel plate of the plate assembly; however, there are also cases where projections are applied to the other steel plate of the plate assembly (see, for example, Patent Document 2). Furthermore, there are also designs where projections are provided on the nut (see Patent Documents 3 and 4), and designs where projections are provided on the washer (see Patent Document 5). Japanese Patent Publication No. 2001-340972Japanese Patent Publication No. 2002-103056Japanese Patent Publication No. 2013-078784Japanese Patent Publication No. 2004-050280Japanese Patent Publication No. 2016-159360 Perspective view showing the appearance of a projection welding member according to one embodiment of the present invention.Figure 1 shows the projection welded member as viewed from the direction of arrow A.Longitudinal section of the projection welded member along line B-B in Figure 1.A perspective view showing the appearance of a modified example of a projection welding member according to one embodiment of the present invention.Figure 4 shows the projection welded member viewed from the direction of arrow E.Figure 4 shows a longitudinal section of the projection welded member along the line F-F.(a), (b) Diagrams illustrating conventional projection(a), (b) Diagrams illustrating other conventional projections.Figure 7 shows a conventional welding process using projection.Side view showing the external appearance of a resistance welding machine. Before describing one embodiment of the projection welding member of the present invention, an example of a resistance welding apparatus used for resistance welding will be described. Figure 10 is a side view showing the external appearance of the resistance welding apparatus 500 developed by the present inventors. In this figure, the resistance welding apparatus 500 comprises a vertically oriented welding gun (hereinafter referred to as a "vertical gun") 502, a table electrode 503, a support column 513, a support arm 514, a frame 515, a welding transformer 516, a power supply cable 517, and a control device 518. The vertical gun 502 comprises a shank holder 505, a crankshaft 506, a gun shaft 507, a gun holder 508, a handle 509, a pressurizing device 510, and a power supply device 511. An electrode 540 is mounted on the shank holder 505 via a shank 530. The shank holder 505, crankshaft 5