| 摘要 |
PURPOSE:To manufacture a gear shift fork with a large Young's modulous at cost by punching a blank material into a metallic material which has a hole, reducing it and forming gear contacting parts and shaft hole parts at axially symmetric positions of projection parts, and bending the material along an axial line and connecting them together. CONSTITUTION:The blank material 10 is punched for an external and an internal shape to obtain a blank 12 having the elliptic hole 14 in the center. This hole 14 is symmetric about a short axis 16, and may be circular. Then, the gear contacting parts 20 and 22 are formed as projection parts at both sides of the short axis 16 and projection parts 23 which decrease in height gradually from both lengthwise ends to the center are formed along the outer circumfernce. Shaft holes 24 and 26 are formed near both lengthwise ends, and the material is folded along the short axis 16 to the opposite side to the projection side; and spot welding in a weld zone 28 is performed to form the gear shift fork 30. Then, coining is performed to grind the gear contacting surfaces and then surface is hardened. |
