| 摘要 |
A plastic gear includes a teeth part formed on its outer periphery, a web formed on the inner side of the teeth part and a plurality of ring-shaped rims concentrically formed such that the web is divided into a plurality of ring-shaped webs in a concentrically circular shape. The plurality of ring-shaped webs includes two or more ring-shaped webs without rib which has no ribs connecting adjacent ring-shaped rims on an outer peripheral side other than the ring-shaped web to which gates for resin molding are to be disposed at the time of resin molding.
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