| 摘要 |
A resin ring is integrally formed on an outer peripheral face of a metal ring to form a hub. On a lower end portion side of the resin ring, a step portion exposing the metal ring is formed. A positioning portion with which the step portion of the hub can be fitted is formed at a central portion of a lower flange. Positions in a height direction of lower end faces of the resin ring and the metal ring are different from each other. Even if a minute gap exists between the metal ring and a metal mold for molding the hub and fluid resin flows into the gap to produce a burr, the burr does not reach the lower end face of the metal ring. Therefore, variations due to the burr do not occur in the lower end face of the hub for positioning in dimension of product.
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