| 摘要 |
An injection molded resin gear 1 , which is molded by injecting a resin material from a plurality of pinpoint gates 13 into a cavity 2 of a die, includes a rim 7 having teeth 8 on its outer periphery, a shaft supporting portion 5 into which a shaft 3 is to be fitted, a web 6 extending in radial directions to connect the rim 7 to the shaft supporting portion 5 , and a plurality of resin flow velocity regulating grooves 11 . When the resin material injected from the pin point gates 13 flows in the cavity 2 outwardly in radial directions, the uniformity of the flow velocity of the resin material passing over portions of the cavity 2 corresponding to the resin flow velocity regulating grooves 11 is improved, and the uniformity of the flow velocity of the resin material passing over a portion of the cavity 2 corresponding to an outside circumferential groove 12 is more sufficiently improved, so that the uniformity of the flow velocity of the resin material in a portion of the cavity 2 corresponding to the web 6 is improved before the resin material reaches a portion of the cavity 2 corresponding to the rim 7.
|
