Patent ID: 7305899

Claim:
A starter comprising: a motor that generates a rotation force; a planetary reduction gear device that reduces speed of the rotation of the motor; a one-way clutch that has a clutch outer portion receiving the rotation from the planetary reduction gear device, a roller, and a clutch inner portion receiving torque from the clutch outer portion through the roller, the clutch inner portion having helical splines on an inner periphery; an output shaft that has helical splines engaging with the helical splines of the clutch inner portion and is disposed movably in an axial direction in the inner periphery of the clutch inner portion through relative rotation of the helical splines; and a pinion gear disposed on the output shaft and movable with the output shaft in a direction opposite to the motor, wherein the clutch inner portion is provided with a stopper on the inner periphery, and the stopper is disposed to receive the end of the helical splines of the output shaft when the output shaft is moved in the direction opposite to the motor, thereby to stop the movement of the output shaft, the output shaft has a first end and a second end, the second end being closer to the motor than the first end and disposed in the inner periphery of the clutch inner portion, the clutch outer portion has a separation wall that extends in a radial direction to an outside diameter of the clutch outer portion axially between a rotation shaft of the motor and the second end of the output shaft, and the separation wall fully covers an axial end of the one way clutch and an axial end face of the second end of the output shaft and is disposed such that an axial end face of the second end of the output shaft is brought into contact with the separation wall when the output shaft is moved toward the motor.