| 摘要 |
<p>PROBLEM TO BE SOLVED: To lighten weight and reduce manufacturing cost, in an extension auxiliary shaft of a compound speed changer. SOLUTION: A first part 204 having a cup-shaped cavity 218 opened to the rear end is formed by hot forging. A second part 206 having cup-shaped cavities 220, 222 respectively opened to a front/rear end is formed by hot forging. To the rear end of the first part 204, the front end of the second part is friction welded, a closed internal cavity 216 is formed. A workpiece 200 thus formed applies machine work, heat treatment and surface treatment an extension auxiliary shaft of a compound speed changer is manufactured. By suitably selecting a material of first/second/third parts 204, 206, 208, necessary strength can be easily obtained in each part. By providing the closed internal cavities 214, 216, lightening of weight and saving of material can be attained.</p> |
