Abstract: In a starter, a cylindrical tube is slidablly engaged with an outer peripheral surface of an output shaft through a bearing in an axial direction. A front end of the tube, which supports a pinion, is closed to define an enclosed space between the front end of the tube and an end of the output shaft. A ventilation groove is formed on an inner cylindrical surface of the tube to communicate the enclosed space with a space defined rearward of the bearing. The ventilation groove has a helical shape twisted about an axis of the tube. When the bearing is press-fitted in the tube, a direction of press-fitting the tube and a direction along the ventilation groove do not coincide, but cross each other.

Abstract: A front end of a starter motor housing is sealed by a resilient seal member disposed between a bearing and a front end wall of the housing. A shaft carrying a pinion at its front end is rotatably and slidably supported by the bearing in an over hang fashion. The seal member is a cup-shaped ring having a circular outer wall, a bottom wall and a center hole. A sealing lip slidably contacting the rotating shaft is formed around the center hole. The circular outer wall of the seal member is tightly and hermetically held between an outer ring of the bearing and front end wall of the housing, so that the seal member is not displaced in the axial direction. The bottom wall is S-shaped forming a depressed portion facing the bearing to provide more space for retaining lubricant therein.

Abstract: In an electromagnetic switch of a starter, a bobbin has two terminal holders on a flange. Each of the terminal holders defines a slot on its end surface and a terminal is press-fitted in the slot in an axial direction of the bobbin. An end of an excitation coil wound around the bobbin is pulled out the bobbin and connected to the terminal. A molded cover provides a through hole and is mounted on the terminal so that the terminal passes through the through hole. A sealing member is press-fitted on the terminal to air-tightly seal the through hole. A rod cover fitted on a rod supporting a movable contact has slits on its cylindrical part in the axial direction. The slits are closed before a distal end of the cylindrical part.

Abstract: In a starter, a pinion is fitted on a pinion shaft such that a rear end surface of the pinion is pressed against a thrust receiving wall provided on the pinion shaft, while a front end surface of the pinion is pressed backward by a detent ring. The detent ring has a tapered surface and fitted in a recess provided on a pinion shaft. A front rising wall defining the recess has a tapered wall so as to correspond to the tapered surface. Since resiliency of the detent ring constricting radially inward is applied to the tapered wall, a component force of the resiliency pressing the pinion axially backward is generated. Thus, the pinion is restricted from moving axially backward by pressing a rear end surface against a thrust receiving wall of the pinion shaft, while the front side surface of the pinion is pressed axially backward through the detent ring.