Patent ID: 7479084

Claim:
A range gearbox for motor vehicles adapted to be connected to the output side of a basic gearbox, the range gearbox comprising: a planetary gear ( 7 ), enclosed in a housing ( 3 ), with a sun wheel ( 9 ) arranged on an input shaft ( 5 ) and engaged with planet wheels ( 10 ), said planet wheels being carried by a planet wheel carrier ( 12 ) connected to an output shaft ( 8 ) and engageable with an axially displaceable ring gear ( 14 ); said ring gear ( 14 ) being selectively lockable, via a coupling means, in a first coupling position in which the gear ( 14 ) is non-rotatably connected to the housing in order to establish gearing between the input shaft and the output shaft, and in a second coupling position in which the gear ( 14 ) is non-rotatably connected to one of the input shaft and the output shaft in order to establish direct drive therebetween; and interacting tooth faces of the planetary gear ( 7 ) are angled in such a manner in relation to the longitudinal axis of the input shaft ( 5 ) and the output shaft ( 8 ) that an axial force arises on the ring gear ( 14 ) from gear speed changes during synchronizing, and this axial force assists movement of the ring gear in the same direction as an external shifting to a low range configuration of the gearbox.