Patent ID: 8444904

Claim:
A method of manufacturing a resin gear, the resin gear comprising: a circular plate; a rim provided in an outer peripheral part of the plate; teeth formed on an outer periphery of the rim; a boss provided in a central part of the plate; and a circular rib provided on the plate between the boss and the rim and concentrically with the plate; the method comprising: forming the resin gear as a single component by injecting a molten material through a plurality of gates arranged at equally spaced intervals circumferentially on the circular rib, wherein the resin gear is formed with a plurality of inner thin-wall portions which are thinner than the rib in an axial direction on the plate between the circular rib and the boss, each of the plurality of inner thin-wall portions being arranged to correspond with a different gate of the plurality of gates, and being symmetrical with respect to a plurality of radial lines passing through the center of the plate and each of the plurality of gates wherein each inner thin-wall portion is of a length in a radial direction, which is shorter in a section closer to a midpoint between adjacent two of the gates than a section closest to the gate.