| 摘要 |
To make a peripheral lip region to be formed with chamfered portions by the use of a plastic working technique, to enable the use of a cup forming punch of a simplified shape so that a mold used therewith can be easily assembled and the punch when worn down can easily be repaired, a method of making an outer race of a constant velocity universal joint of a tripod type includes an upsetting step during which not only are outer peripheral shapes of a small diameter portion (W3a) and a large diameter portion (W3b) defined, but a recess (Wb) having a tapered peripheral wall face (Wba), which eventually defines general shapes of the chamfered portions (10) of the outer race (1), is formed in an end face of the large diameter portion (W3b). During a cup forming step, the tapered peripheral wall face (Wba) defined during the upsetting step is rearwardly pushed while its shape is maintained. Thereafter, a cup drawing step is carried out to finish the tapered peripheral wall face (Wba) to represent the final design shapes of the chamfered portions (10).
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