| 摘要 |
PROBLEM TO BE SOLVED: To provide a retainer for a valve spring capable of restraining a jumping-out phenomenon, and capable of enhancing productivity, even if the retainer is made of a titanium alloy. SOLUTION: This retainer 30B for the valve spring includes a collar part 31 contacting with the valve spring and a cylindrical part 32B inserted into the valve spring. A side surface of the cylindrical part 32B is formed as a conical surface 34 expanding toward the collar part 31. Thus, since the side surface of the cylindrical part is formed as the conical surface expanding toward the collar part, the retainer 30B can be easily thrust out from a lower die. As a result, thrust-out is facilitated, and the productivity can be enhanced. In addition, since this retainer 30B can be achieved only by changing a straight hole to a tapered hole by treatment applied to a die, there is no risk of increasing die cost. Since the jumping-out phenomenon is not caused, there is no need to take countermeasure against jumping-out. COPYRIGHT: (C)2007,JPO&INPIT
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