| 摘要 |
PURPOSE:To improve shape accuracy by applying a plurality of tack weldings to a front side kick board in a width direction of its start line section to form the kick board into a V-shape in cross section, applying a plurality of plug weldings to a tread section in its width direction and thereafter forming a rear side kick board into a V-shape. CONSTITUTION:Spot weldings S1 are applied to a section, in its width direction, where a front side kick board 2 of damping steel plate 1 is to be formed to apply spot welding to front and rear steel plates 1a, 1b. When the board 2 is formed into a V-shape by bending in a direction of its surface having protrusions by means of a V-groove die, an offset L is produced by said bending at the edge of a section where a rear side kick board 4 is to be formed. Thereafter two rows of spot weldings S2 are applied in a width direction to a section where a tread 3 is to be formed to apply spot weldings to the steel plates 1a, 1b. And the rear side kick board 4 is formed into a V-shape by bending in a direction opposite to that of the kick board 2. In this manner, the offset L is eliminated and hence shape accuracy can be improved. |
