Multi-stage automatic transmission

摘要

A multi-stage automatic transmission in which planet gear mechanisms, external gears and friction elements are combined in order to realize nine forward gears and one rearward gear having excellent operating conditions for friction elements and superior shift range ratios, thereby achieving excellent power performance and fuel efficiency.

主权项

1. A multi-stage automatic transmission comprising:
an input shaft; an output shaft disposed parallel to the input shaft; a first planet gear mechanism coaxially disposed on the input shaft, the first planet gear mechanism having two rotary elements connected to the input shaft so as to engage with and disengage from the input shaft; a second planet gear mechanism connected to the first planet gear mechanism via a plurality of pairs of external gears, the second planet gear mechanism being connected to the output shaft; the plurality of pairs of external gears for transferring power between one rotary element of the rotary elements of the second planet gear mechanism that is connected to neither the first planet gear mechanism nor the output shaft and the input shaft; a plurality of power engaging/disengaging members for switching power transmission via the plurality of pairs of external gears between the rotary elements of the second planet mechanism and the input shaft; and a restraint member capable of halting a movement of one rotary element of the rotary elements of the second planet gear mechanism connected to neither the first planet gear mechanism nor the output shaft.