| 摘要 |
PROBLEM TO BE SOLVED: To attain a mass production and a reduction in cost by press molding a gear case and a bottom plate, mutually fitting the opening and projection provided on the respective connecting surfaces, and integrating the fitting part by welding. SOLUTION: A gear case 1 is obtained by press molding a steel plate into a substantially square reversed cup shape. At this time, the lower periphery is drawn to form an upper surface part, and the lower periphery is extended to form a square collar bottom part and a surrounding inside wall part. A bottom plate 4 is formed by press molding a thick steel plate so that the outer surface of the circumferential edge is continued to the surrounding inside wall part of the gear case 1. Further, a mounting projection for welding connection is formed thereon. In the welding connection of the gear case 1 to the bottom plate 4, the circumferential edge of the bottom plate 4 is connected to the inner wall surface of the surrounding inside wall part of the gear case 1, and the mounting projection of the bottom plate 4 is fitted to the bottom plate welding mounting hole of the gear case 1. The vicinity of the periphery of the bottom plate welding hole is integrally fused to the mounting projection part of the bottom plate 4.
|
