Patent ID: 8479599

Claim:
A starter for an internal combustion engine comprising: a power transmission mechanism that includes: an engine-side power transmission member fastened to an engine output shaft, the engine-side power transmission member includes a flywheel and an outer race plate that is separate from the flywheel; an electric-motor-side power transmission member provided rotatably relative to the engine output shaft and coupled to a rotational shaft of an electric motor for starting the engine; a one-way clutch provided between the engine-side power transmission member and the electric-motor-side power transmission member to permit torque transmission in a direction from the electric-motor-side power transmission member to the engine-side power transmission member; and a sealing member respectively provided between the engine-side power transmission member and the electric-motor-side power transmission member, and between an engine body and the electric-motor-side power transmission member, wherein the starter for an internal combustion engine uses lubricant supplied from the engine body to the interior of the power transmission mechanism to lubricate the power transmission mechanism, a partially recessed portion that includes a first protruding portion that seals between the engine output shaft and the engine-side power transmission member is formed in the entire circumferential direction of the engine output shaft on at least one of a contact surface of the engine output shaft and a contact surface of the outer race plate facing the surface of the engine output shaft of the engine-side power transmission member in a contact portion between the engine output shaft and the outer race plate of the engine-side power transmission member, and the contact surface of the engine output shaft that contacts a surface of the outer race plate faces in the axial direction, and the engine output shaft includes a second protruding portion that extends in an axial direction of the engine output shaft to be located inside an inner circumferential surface of the outer race plate in a radial direction of the outer race plate.