The axial play or movement permitted to the drive shaft of a starter motor must be accurately controlled. It has previously been proposed to control the axial play or movement of the drive shaft of a starter motor by placing a U-shaped disk on the shaft between the commutator and the bearing adjacent thereto, and then controlling the axial play by fitting shins between the U-shaped disk and the bearing. The starter motor, upon having started the engine and being placed in over-running condition, should be stopped as quickly as possible by braking. In order to brake the overrun, or run-out of the starter motor after having started the engine, the facing side of the commutator rubs against the inner facing of the side of the commutator bearing, requiring a certain longitudinal or axial movement of the drive shaft. Due to wear of the facing side of the commutator, the axial movement of the drive shaft becomes larger. If the run-out or over-run brake is located at different positions in the starter, it is still necessary to control the axial movement of the shaft of the starter by measuring the fitting appropriate shims or disks between the bearing adjacent the commutator and a U-shaped disk fitted into a ring groove of the starter. Manufacture of the starter thus requires individual matching, and thus is costly from labor and assembly point of view, and difficult to accurately control in manufacture. The end of the starter shaft which extends from the bearing adjacent the commutator has to be additionally closed off with a cap and a sealing ring which, further, increases assembly costs and additionally contributes to increasing the axial length of the starter, thus making eventual fitting of the starter into an automotive vehicle more difficult.
USPTO Backgrounds
USPTO Backgrounds