An engaging device and a starter comprising the engaging device, the starter comprises an electric motor, a speed reducer connected with the electric motor, an overrunning clutch comprising a driving piece connected with the speed reducer and a driven piece, and an engaging device with a main shaft connected with the driven piece of the overrunning clutch. A quick engagement may be achieved and a certain initial engagement depth is guaranteed. During the engaging process, the pinion may mesh into a ring gear in its own initiative, reducing the effect of teeth milling phenomenon on the ring gear to a maximum extent.

A starter assembly is provided and includes a shaft to transmit rotation to a ring gear via a pinion and including a first helical spline with angling directed reversely with respect to a direction of the rotation and an elastic element anchored on the first helical spline to bias the pinion in an axial direction. The ring gear and the pinion include complementary teeth and the pinion defines a bore with a second helical spline to register with the first helical spline such that the pinion teeth are forwardly rotated into ring gear teeth engagement positions as the shaft moves axially relative to the pinion in the axial direction.

A starting device for an internal combustion engine has a starter pinion which can be adjusted axially between an out-of-function position and an advanced drive position and is seated on a shaft, on which a securing ring is arranged in order to limit the axial movement of the starter pinion. A securing recess is made in the end side of the starter pinion, into which securing recess the securing ring protrudes and which fixes the securing ring radially in its position on the shaft. The starter pinion can be displaced axially into a removal position.