| 摘要 |
A primary product is formed by performing forward extrusion of a work in the first step, and a secondary product is formed by performing swaging in the second step. In the third step, preliminary pushing of the upper surface of the secondary product is performed to obtain a tertiary product where a recess generally matching the longitudinal section in the axial direction of the bottom wall of a cup portion of the final product is formed in the upper surface. In the fourth step, a quaternary product having a cup portion provided with a ball rolling groove in the inner wall is formed by performing backward extrusion of the tertiary product by using a punch having a tip shape generally matching the longitudinal section of the recess. Finally, in the fifth step, an outer ring member is produced as a final product by performing ironing of the cup portion of the quaternary product.
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