Multiple speed transmission

摘要

A family of transmission gearing arrangements produces nine forward and one reverse speed ratio by selective engagement of various combinations of three clutches or brakes. Each transmission gearing arrangement includes a front shiftable gearing arrangement configured to establish a variety of speed ratios between an intermediate shaft and an input shaft. These speed ratios include a reverse speed ratio, a zero speed ratio, two underdrive ratios, and a direct ratio. Each transmission also includes a rear shiftable gearing arrangement configured to selectively establish particular speed relationships among the input shaft, the intermediate shaft, and an output shaft. Engagement of a clutch in the rear shiftable gearing arrangement establishes an underdrive ratio between the output shaft and the intermediate shaft. Engagement of another clutch in the rear shiftable gearing arrangement constrains the speed of the input shaft to be a weighted average between the speed of the intermediate shaft and the output shaft.

主权项

1. A transmission comprising:
an input shaft; an output shaft; a first intermediate shaft; a first shiftable gearing arrangement configured to selectively establish at least five speed ratios between the first intermediate shaft and the input shaft, the speed ratios including a reverse ratio, a zero ratio, two underdrive ratios, and a direct drive ratio; a second shiftable gearing arrangement configured to selectively constrain the output shaft to rotate at a speed between zero and a speed of the first intermediate shaft, the second shiftable gearing arrangement comprising a first simple planetary gear set having a first sun gear fixedly held against rotation, a first planet carrier coupled to the output shaft, a first ring gear coupled to the first intermediate shaft, and a first plurality of planet gears supported for rotation relative to the first planet carrier and in continuous meshing engagement with both the first sun gear and the first ring gear; and a first fixed gearing arrangement configured to fixedly constrain the input shaft to rotate at a speed between speeds of an eighth element and a sixth element, wherein the eighth element is coupled to the first intermediate shaft and the sixth element is coupled to the output shaft.