Continuously variable transmissions for motor vehicles

摘要

A transmission for transferring torque from a prime mover includes a first input shaft adapted to be driven by the prime mover, a second input shaft, an output shaft and an epicyclic gearset. The gearset includes a ring gear being driven by the first input shaft, pinion gears being driven by the ring gear, a sun gear driven by the second input shaft and driving the pinion gears, and a carrier driving the output shaft. A reaction motor drives the second input shaft. A controller controls the reaction motor to vary the speed of the second input shaft and define a gear ratio between the first input shaft and the output shaft based on the second input shaft speed.

主权项

1. A continuously variable transmission for a motor vehicle having a powertrain and a driveline driving a pair of wheels, the transmission comprising:
a solar epicyclic gearset including a ring gear adapted to be driven by the powertrain, a sun gear, a carrier adapted to drive the driveline, and pinion gears rotatably supported by the carrier and which are meshed with the ring gear and the sun gear; a reaction motor driving the sun gear; and a controller for controlling the reaction motor to vary the speed of the sun gear and define a gear ratio between the ring gear and the carrier based on the sun gear speed, wherein a vertical asymptote of a ratio of ring gear speed to carrier speed versus a ratio of sun gear speed to ring gear speed for the solar epicyclic gearset ranges between about −1 and −10.