Patent ID: 9638289
Date: 2017-05-02
CPC Classifications: F16H

Claim:
1. A multi-stage transmission for a vehicle, comprising: an input shaft; an output shaft; first, second, third and fourth planetary gear devices disposed between the input shaft and the output shaft to transmit rotary forces, each of the first, second, third and fourth planetary gear devices having three rotary elements; and at least six shifting elements connected to the rotary elements of the planetary gear devices; wherein a first rotary element of the first planetary gear device is installed to be fixable by one shifting element of the at least six shifting elements and permanently connected to a second rotary element of the third planetary gear device and a third rotary element of the fourth planetary gear device, a second rotary element of the first planetary gear device is variably connected to a third rotary element of the second planetary gear device and a third rotary element of the third planetary gear device, and a third rotary element of the first planetary gear device is variably connected to a first rotary element and a second rotary element of the second planetary gear device; wherein the first rotary element of the second planetary gear device is installed to be fixable by another shifting element of the at least six shifting elements, the second rotary element of the second planetary gear device is permanently connected to the input shaft, and the third rotary element of the second planetary gear device is permanently connected to a first rotary element of the third planetary gear device; wherein the first rotary element of the third planetary gear device is permanently connected to a first rotary element of the fourth planetary gear device; and wherein a second rotary element of the fourth planetary gear device is permanently connected to the output shaft.