Powershift gearbox/transmission

A motor-vehicle transmission shiftable under load, comprising:

• a main gear set including:
• a main input shaft,
• respective gear trains defining two torque-transmitting paths, each of said gear trains having two selectively effective groups of gears including a gear fixed to said main input shaft and a free gear rotatable about an axis common to free gears of the other groups,
• a respective coaxial secondary input shaft for each train lying along said axis and carrying rotatably the free gears of the respective train,
• respective synchronizing clutches for selectively coupling one of said free gears rotatably with the respective secondary input shaft, and
• a double clutch disposed along said axis between said gear trains and formed as a unit with two selectively operable clutches each adapted to connect a respective one of said secondary input shafts with a single main-gear-set output shaft coaxial with said secondary input shafts, one of said secondary input shafts being hollow and journaled on said main-gear-set output shaft;
• a reversing gear set having:
• a pair of free gears rotatable on a common axis,
• a reversing clutch selectively coupling said free gears of said reversing gear set to select an output rotation direction of the transmission, and
• fixed gears cooperating with said free gears of said reversing gear set to define opposite-sense rotational directions in accordance with the free gear coupled to the reversing clutch;
• a range change gear set coupled to said reversing gear set and including:
• a pair of free gears rotatable about a common axis,
• a range-change clutch selectively coupling said free gears of said range change gear set to select respective speed ranges in accordance with the free gear coupled to said range-change clutch, said free gears of said range change gear set cooperating with said fixed gears of said reversing gear set;
• a common shaft fixed to and carrying said fixed gears of said reversing gear set and said range change gear set;
• a final output shaft parallel to but offset from said common shaft, said free gears and said range-change clutch of said range change gear set being provided on one of said output shafts and said free gears and said reversing clutch of said reversing gear set being provided on the other of said output shafts;
• and
• an output gear on said final output shaft for driving wheels of said vehicle.