Starting motor

A starting motor comprising: an overrunning clutch (40) including an output shaft (7) adapted to receive rotation of an armature shaft (2) of a d.c. motor (1), a clutch outer (41) adapted to be coupled to the output shaft (7) through a helical spline (8), and a clutch inner (22) coupled to the clutch outer (41) through a roller (23) and transmitting a one-way rotation to a pinion (28) provided at a front end side; a retainer (27) fitted to a rear end part of the output shaft (7), and adapted to receive a rear end of the clutch outer (41) which has returned to a backward position; a supporting frame (17) fixed to a fixed part, and supporting the rear end part of the output shaft (7) through a bearing (18); and a shift lever (34) having a lower end part engaged with an annular engagement groove (41c) in an axial direction, and turning to move the overrunning clutch (40) to either one of a forward position and the backward position, the annular engagement groove (41c) provided with a rear side part of the clutch outer (41); wherein the annular engagement groove (41c) in the overrunning clutch (40) is adapted to have a rear end side inner periphery overhung the retainer (27) when the clutch outer (41) is in the backward position, and the inner periphery is formed to have a larger diameter than an outer periphery of an outer end of the bearing supporting part of the supporting frame (17).