Patent ID: 7160221

Claim:
A range gearbox ( 1 ) for motor vehicles configured to be connected to an output side of a basic gearbox of the vehicle, said range gearbox ( 1 ) comprising: an input shaft ( 2 ) from the basic gearbox, an output shaft ( 3 ) configured to be connected to a transmission of the vehicle, a planetary gear ( 4 ) arranged between the input shaft ( 2 ) and the output shaft ( 3 ), a ring gear ( 18 ) of the planetary gear ( 4 ) being axially displaceable by a first means ( 27 ) for axial displacement of the ring gear ( 18 ), a first coupling ring ( 10 ) that engages a high-range mode, and a second coupling ring ( 16 ) that engages a low-range mode, said coupling rings ( 10 , 16 ) and the ring gear ( 18 ) being alternatively engageable; at least one synchronizing means ( 15 ) with at least one friction surface ( 22 ), said synchronizing means ( 15 ) configured to synchronize the rotational speed difference between the ring gear ( 18 ) and the second coupling ring ( 16 ) by interaction with a corresponding at least one friction surface ( 23 ) arranged on the second coupling ring ( 16 ); and said synchronizing means ( 15 ) and the second coupling ring ( 16 ) being arranged coaxially outside the ring gear ( 18 ), and at least one second means ( 25 ) for engaging at least the second coupling ring ( 16 ) and a third means ( 25 , 25 b ) for driving said synchronizing means ( 15 ) being arranged on the external side, as seen radially, of the ring gear ( 18 ), and the synchronizing means ( 15 ) being arranged between the first means ( 27 ) and the second coupling ring ( 16 ).