| 摘要 |
<p>It is an object of the invention to provide a method of manufacturing an inner ring for a rolling bearing in which the directions of the metal flows of the inner ring can be made substantially parallel to the shape of the race surface of the inner ring to thereby manufacture a rolling bearing inner ring having an enhanced durability. In the manufacturing method, a cylindrical steel billet 1 (shown in FIG. 1 (a) including a large number of metal flows 2 formed in the axial direction of the section thereof is held and upset by and between first upper and lower metallic molds 4a and 4b each having a transfer surface 3 for the race surface of the inner ring and, at the same time, recesses 6 are formed in the upper and lower plane portions of the cylindrical steel billet 1 respectively (shown in FIG. 1(c), next after the upper and lower shoulder portions of the recesses are respectively held by and between second upper and lower metallic molds 9a and 9b (shown in FIG. 1 (c), the recesses 6 are pressed equally from above and from below by the second upper and lower metallic molds 9a and 9b to thereby form a centrally pressed portion 10, then the inner portion of the centrally pressed portion 10 is removed to thereby produce a ring-shaped workpiece, and finally the ring-shaped workpiece is rolled and shaved to thereby manufacture an inner ring.</p> |
