Coupling device between ICE output shaft of hybrid drive vehicle and input shaft of vehicle change speed gear box

The device has a free wheel (18) interposed between a crankshaft (11) and a rear shaft. The flywheel occupies a free state in which the shafts are not coupled if rotational speed of the driving shaft is inferior to that of the rear shaft. The flywheel otherwise occupies a blocked state in which the two shafts are coupled when the speed driving shaft is equal to that of rear shaft, and the motor coupling force is positive.