Abstract: An in-line gear reduction starter drive for driving a pinion from the armature of an electric cranking motor. The drive utilizes a single central shaft that is directly connected to the armature core of the cranking motor armature and the pinion is supported by the shaft. The shaft has an integral gear which forms the sun gear of a planetary gear set. The sun gear drives planet gears which in turn drive a driven member that is rotatably supported by the shaft and which drives the pinion.

Abstract: A two piece armature shaft for a vehicle starter motor comprises a hollow tubular member with an open end and a portion being adapted to receive armature core laminations, said portion possibly being of greater diameter than the open end. The armature shaft further comprises a solid cylindrical member provided with spiral spline grooves for engagement with the normal clutch and pinion drive assembly, the solid cylindrical member being received coaxially in the open end of the tubular member with portions of the open end being staked into the spline grooves to combine the members into one shaft, the portions of the open end not so staked providing an axial stop for the clutch and pinion drive assembly.