Patent ID: 7900763

Claim:
Coupling device between a rotor of a reversible rotating electrical machine and a main shaft of a gearbox of a heat engine of a motor vehicle hybrid drive train, the rotor being integral with a hub mounted concentrically with the main shaft and rotatable with respect to a stationary case housing a stator of the electrical machine, defining a gap between the stator and the rotor, the main shaft being able to be rotationally uncoupled from the engine crankshaft via a clutch that can be disengaged by a clutch release control, wherein the hub of the rotor is coupled to the main shaft via a coupling part comprising (i) an externally toothed ring gear meshing inside the hub of the rotor, and (ii) a central sleeve mounted directly on the main shaft while being coupled to the main shaft via a splined connection, wherein each of the toothed ring gear and the central sleeve of the coupling part has a respective cylindrical end having a smooth peripheral surface, wherein the two cylindrical ends are located opposite the respective teeth and splines coupling the coupling part to the hub of the rotor and to the main shaft, and wherein each of the hub of the rotor and the main shaft has a respective smooth cylindrical surface facing the respective smooth peripheral surface of the respective cylindrical end of the ring gear and the central sleeve, so that the cylindrical ends of the ring gear and of the central sleeve are centered in the hub of the rotor and on the main shaft, respectively, via a slip fit or sliding fit, wherein the main shaft has a stop shoulder, and the central sleeve bears on the stop shoulder of the main shaft, so that the coupling part is translationally blocked in a first direction with respect to the main shaft, and wherein the toothed ring gear has a stop shoulder, and the hub of the rotor bears on the stop shoulder of the ring gear, so that the coupling part is translationally blocked in a second direction opposite the first direction with respect to the rotor.