Coupling device of the rear axle of a four wheel drive vehicle allowing a quick decoupling

The device has a planetary gear set (3), comprising a casing (11) integrated to a frame of a motor vehicle. A gear set comprises a planet gear (5) connected in rotation to a longitudinal drive shaft (2). The gear set comprises a satellite holder (6) for carrying a satellite (7), where the holder is integrated to a conical pinion (8) meshing with a conical wheel (9) of a rear axle (1). A crown (4) is related in rotation to the casing by an intermediary of a disengageable connection device i.e. wet type plate clutch.