| 摘要 |
PURPOSE:To satisfactorily set both of a key part and parts except the key part by providing projecting parts corresponding to the positions of a key step part to upper and lower punches used for setting a piston ring of which the joint part has the key step shape. CONSTITUTION:A setting die for the sintered alloy piston ring of which the joint part has the key step shape is constituted of a die 4 of which the inside peripheral face has the free shape of the piston ring as well as the upper punch 2 and lower punch 3 fitting thereto. The projecting parts 21, 31 corresponding to the key step are provided to the key step position of a sintered body stock 1 for the upper and lower punches 2, 3. The projecting part 22 and a recess 32 to be fitted to each other in the stage of setting are provided to the punches 2, 3. The length on the inner side of the die is made shorter by about 1% than the outside peripheral length of the sintered body. The sintered body stock 1 is compressed in width by about 1-10% of the size by using such die, by which said stock is set. The setting of both the key part of the piston ring and the other parts is thereby satisfactorily executed.
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