| 摘要 |
PROBLEM TO BE SOLVED: To solve such a problem with a side rail of a combined oil ring that the side rail of the combined oil ring subjected to nitriding on the outer peripheral surface thereof causes a large deformation on a disk, and a specified outside diameter dimension cannot be provided. SOLUTION: The material of the side rail is formed by coiling beforehand to manufacture a coil 1. The coil is expandedly brought into contact with the inner peripheral surface of a fixture 6 having a specified dimension on the inner peripheral surface thereof. The fixture 6 is loosened, and the coil 1 is re-tightened. In this state, nitriding is applied to the coil, and the coil 1 is cut off in axial direction to provide the side rail. COPYRIGHT: (C)2004,JPO
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