Patent ID: 7406891

Claim:
An injection molded resin gear molded by injecting a resin material from a pin point gate into a cavity of a die, said injection molded resin gear comprising: a rim having teeth on the outer periphery thereof; a shaft supporting portion for receiving and supporting a shaft therein; a web extending in radial directions to connect said rim to said shaft supporting portion; and a resin flow velocity regulating groove formed in one side of said web so as to be arranged in the vicinity of the pin point gate when the resin material is injected from the pin point gate into the cavity of the die, said resin flow velocity regulating groove having a shape which corresponds to that of a resin flow velocity regulating protrusion of the die for restricting the radial flow of the resin material, which is injected from the pin point gate, to cause the resin material to flow at a uniform velocity in radial directions between the pin point gate and a portion of the cavity corresponding to said rim, wherein said resin flow velocity regulating groove includes a first groove portion which is arranged so as to face the pin point gate in radial directions when the resin material is injected from the pin point gate, and a pair of second groove portions, each of which extends from an end of the first groove portion in a circumferential direction so as to have a gradually decreasing groove depth, and said injection molded resin gear further comprises a first annular groove which is formed in said one side of said web outside of said resin flow velocity regulating groove in radial directions so as to be concentric with said rim.