Patent ID: 7578762

Claim:
A four-wheel-drive vehicle transmission ( 1 ) comprising: an input shaft ( 8 ) rotated by a vehicle engine ( 2 ) about a first axis of rotation (A); a front output shaft ( 10 ) connected to a front axle ( 3 ); a rear output shaft ( 12 ) connected to a rear axle ( 4 ); said input shaft ( 8 ) and said rear output shaft ( 12 ) being coaxial; an auxiliary tubular shaft ( 14 ) mounted alongside said input shaft ( 8 ) to rotate about a second axis of rotation (D) parallel to said first axis of rotation (A); at least one first group of gears ( 15 , 16 ) for selectively connecting said auxiliary tubular shaft ( 14 ) mechanically to said input shaft ( 8 ); a first countershaft ( 17 ) mounted for rotation about said second axis of rotation (D) inside said auxiliary tubular shaft ( 14 ); a second countershaft ( 18 ) mounted for rotation about said second axis of rotation (D) opposite said first countershaft ( 17 ); a planetary gear train ( 19 ) for mechanically connecting said auxiliary tubular shaft ( 14 ) to said first countershaft ( 17 ) and said second countershaft ( 18 ); and a first ( 25 ) and a second ( 26 ) cascade gear set for mechanically connecting said second countershaft ( 18 ) to said rear output shaft ( 12 ), and mechanically connecting said first countershaft ( 17 ) to said front output shaft respectively ( 10 ); said front output shaft ( 10 ) and said rear output shaft ( 12 ) are mounted for rotation respectively about a third axis of rotation (B) and a fourth axis of rotation (C), said third axis of rotation (B) and said fourth axis of rotation (C) parallel to said first axis of rotation (A): and said planetary gear train ( 19 ) positioned between said first countershaft ( 17 ) and said second countershaft ( 18 ), said planetary gear train ( 19 ) comprising: a pinion ( 20 ) fitted to the end of said first countershaft ( 17 ); a ring gear ( 21 ) carried by said auxiliary tubular shaft ( 14 ) so as to be coaxial with said pinion ( 10 ); and a plurality of planet gears ( 23 ) mounted for rotation on a planet carrier flange ( 22 ) fitted to said second countershaft ( 18 ), said plurality of planet gears ( 23 ) meshing with said pinion ( 20 ).