MULTI-SPEED TRANSMISSION

摘要

A family of transmission gearing arrangements produces at least nine forward speed ratios and one reverse speed ratio by selective engagement of three shift elements in various combinations. Each disclosed transmission includes four planetary gear sets, three brakes, and either three or four clutches. One embodiment produces twelve forward speed ratios and two reverse speed ratios. Another embodiment produces thirteen forward speed ratios.

主权项

1. A transmission comprising:
an input shaft, an output shaft, and a third shaft; a first gearing arrangement configured to selectively constrain the third shaft to rotate at various speed ratios relative to the input shaft including a negative ratio, two ratios between zero and one, and one, and to selectively hold the third shaft against rotation; a first simple planetary gear set having a first sun gear fixedly coupled to the third shaft, a first ring gear, a first planet carrier fixedly coupled to the input shaft, and at least one planet gear supported for rotation on the first planet carrier and in continuous meshing engagement with the first sun gear and the first ring gear; a second simple planetary gear set having a second sun gear, a second ring gear fixedly coupled to the third shaft, a second planet carrier fixedly coupled to the output shaft, and at least one planet gear supported for rotation on the second planet carrier and in continuous meshing engagement with the second sun gear and the second ring gear; a first brake configured to selectively hold the second sun gear against rotation; and a first clutch configured to selectively couple the output shaft to the first ring gear.