| 摘要 |
PROBLEM TO BE SOLVED: To avoid the generation of burrs, cracks, or damage in a retaining window during punching work for providing the retaining window for a constant velocity joint retainer. SOLUTION: Side-lying V-shaped first and second grooves 36, 38 are formed on the side peripheral wall of a preliminary molding 40 to be a constant velocity joint retainer 24. During punching work for providing the retaining window 28, a first protruded portion 44a of a punch 44 is inserted into the first groove 36 and a second protruded portion 44b is inserted into the second groove 38. Since the punch 44 is moved, the first groove 36 is cut by the first protruded portion 44a so that its slightly lower part from the side-lying V-shaped front end is left and the second groove 38 is cut by the second protruded portion 44b so that its slightly upper part from the side-lying V-shaped front end is left. COPYRIGHT: (C)2007,JPO&INPIT
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