A planetary transmission for selectively shifting among three forward and one reverse speeds includes first and second sun gears respectively secured to and clutchable to a drive shaft to provide a first forward speed. A planet carrier, secured to a driven shaft, surrounds the sun gears and carries a first planet gear meshing with the first sun gear and a compound planet gear comprising a second planet gear meshing with the first planet gear and a third planet gear meshing with the second sun gear. Respectively concentric with the first and second sun gears are brake-associated first and second ring gears which respectively mesh with the first and third planet gears. First, second, and third brakes are respectively connected to the first ring gear, the second ring gear, and the first sun gear to stop and allow rotation of said gears to provide two forward and one reverse speeds; a third forward speed is provided by clutching the second sun gear to the drive shaft.
A drive transmission unit for a motor vehicle incorporates an expansible-pulley stepless speed changer driving a differential unit via a selectively-operable reversing unit and a bevel-gear reduction stage. The speed changer has a primary shaft which serves as the input shaft of the transmission unit, and a hollow secondary shaft parallel to, and driven from, the primary shaft. An output shaft of the transmission unit extends coaxially through the secondary shaft of the speed changer with the input and output ends of the output shaft projection from opposite ends of the secondary shaft. The reversing unit, which is of epicyclic form, is driven by the secondary shaft and includes a rotatable output member mounted on the input end of the output shaft. The output end of the output shaft drives the bevel-gear reduction stage. The reversing unit can be set in one of three states in which respectively, the secondary and output shafts are arranged to rotate in the same sense, to rotate in opposite senses, and to be drivingly disengaged.
A drive transmission unit for a motor vehicle incorporates an expansible-pulley stepless speed changer arranged to drive a differential unit via a reduction gear box and a selectively-operable reversing unit. The speed changer has a primary shaft which serves as the input shaft of the transmission unit, and a hollow secondary shaft parallel to, and driven from, the primary shaft. The reversing unit, reduction gear box and differential unit are all epicyclic in form and are arranged in that order side-by-side coaxial with the secondary shaft. Two output shafts connect the differential unit to the half shafts of the vehicle with one of the output shafts passing coaxially through the secondary shaft. This arrangement provides for a very compact transmission unit. The reversing unit can be set in one of three states in which respectively, the secondary and output shafts are arranged to rotate in the same sense, to rotate in opposite senses, and to be drivingly disengaged.
A drive transmission unit for a motor vehicle incorporates an expansible-pulley stepless speed changer and a selectively-operable reversing unit. The speed changer has a primary shaft which serves as the input shaft of the transmission unit, and a secondary shaft parallel to, and driven from, the primary shaft. An output shaft of the transmission unit is positioned adjacent one end of the secondary shaft of the speed changer in coaxial alignment therewith and is operatively connected to the secondary shaft by the reversing unit. The reversing unit, which is of epicyclic form, is driven from said one end of the secondary shaft and can be set in one of three states in which respectively, the secondary and output shafts are arranged to rotate in the same sense, to rotate in opposite senses, and to be drivingly disengaged. The reversing unit is coaxial with the secondary and output shafts so that the overall transmission unit is very compact.
