Coupling unit for use in motor vehicle

摘要

A coupling unit comprises a viscous coupling A received within a coupling housing (29) of a friction coupling B so that viscous coupling constitutes a separate closed unit which simplifies maintenance. The housing is connected to an input and hub (12), of the viscous coupling, is connected to an output. Between an end face (17) of the viscous coupling and an end face of a pressure plate (28) of the friction coupling there is provided setting device in the form of balls (42) and opposed ramps which engage the friction coupling after a set torque level has been exceeded. Up to the set torque level, torque is transmitted from the coupling housing to the hub solely by the viscous coupling. Opposed pockets (39), (40) in the end face and the pressure plate accommodate return springs (41) which basis the end face and pressure plate into their starting position so that the setting device is capable of achieving different torque transmitting characteristics in two different directions.