| 摘要 |
PURPOSE:To strengthen the connection between the boss and the flywheel body using the boss of simplified shape by forming an annular groove around the hole in the flywheel body for inserting the boss, and by placing and caulking the annular protrusion in the annular groove to prevent the metal flow. CONSTITUTION:Annular grooves 104, 105, 106 having the V-shape section are formed concentrically ariund the hole 102 in the flywheel body. The male mold processes by drawing the flywheel material in the shape of a cup-like flywheel. At this moment, annular protrusions 502, 804 and 805 bite in the flywheel material to prevent the material from being displaced to deform the hole 102 for inserting the boss. In the last process of caulking, the caulked part crushes the peripheral area of the boss insertion hole 102. At this moment, as the annular protrusion 804 of the male mold is in the annular groove, the direction of the metal flow around the boss insertion hole 102 is ristricted as shown with the arrow (a), the clearance is prevented from being provided between the boss insertion hole 102 and boss 2. |
