TWO-SPEED TRANSMISSION FOR ELECTRIC VEHICLE

摘要

A two-speed transmission for a vehicle is provided including a planetary gear set selectively coupling an input shaft and an output shaft. The planetary gear set is configured to provide two forward gear ratios and neutral. The planetary gear set includes at least one sun gear, at least one pinion in meshing engagement with the sun gear, at least one ring gear meshingly engaged with the pinion, and a carrier. The carrier supports the pinion and is connected to the output shaft such that rotation of the carrier drives the output shaft. The two-speed transmission also includes one or more elements that rotatably couple different combinations of the sun gear, the pinion, the ring gear, the input shaft, and the carrier with one another or a ground. Such elements may include combinations of clutches, brakes, band brakes, dog clutches, and mechanical diodes.

主权项

1. A two-speed transmission that transfers torque from a motor to a final drive unit, comprising:
an input shaft having a first end that connects with the motor and a second end opposite said first end; an output shaft that connects with the final drive unit; a planetary gear set selectively coupling said input shaft and said output shaft; said planetary gear set including a sun gear connected to said input shaft; said planetary gear set including at least one double step pinion having a first gear and a second gear rotatably fixed with said first gear; said first gear having a first outer diameter and said second gear having a second outer diameter that is less than said first outer diameter; said first gear of said at least one double step pinion being meshingly engaged with said sun gear and disposed radially outwardly of said sun gear; said planetary gear set including a ring gear meshingly engaged with said second gear of said at least one double step pinion and circumscribing said second gear of said at least one double step pinion; said planetary gear set including a carrier connected to said output shaft and supporting said at least one double step pinion; a multi-plate wet clutch assembly including a brake fixed to a ground and a clutch connected to said carrier; said brake being connected to said ring gear and providing a first gear ratio by resisting rotation of said ring gear with respect to said ground when said brake is engaged; and said clutch being connected to said input shaft and providing a second gear ratio by rotatably coupling said input shaft and said carrier when said clutch is engaged.