Patent ID: 9638286
Date: 2017-05-02
CPC Classifications: F16H

Claim:
1. A multi-step transmission for a vehicle comprising: an input shaft; an output shaft; first to fourth planetary gear devices disposed between the input shaft and the output shaft to transmit rotary force, each of the first to 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 continuously connected to a third rotary element of the second planetary gear device while being fixable by one shifting element from among the at least six shifting elements, a second rotary element of the first planetary gear device is continuously connected to a second rotary element of the third planetary gear device and a third rotary element of the fourth planetary gear device, and a third rotary element of the first planetary gear device is fixable by another shifting element from among the at least six shifting elements, wherein a first rotary element of the second planetary gear device is selectively connected to a first rotary element of the fourth planetary gear device and the second rotary element of the third planetary gear device, a second rotary element of the second planetary gear device is continuously connected to the input shaft, the third rotary element of the second planetary gear device is continuously connected to a third rotary element of the third planetary gear device, wherein a first rotary element of the third planetary gear device is selectively connected to the first rotary element and a second rotary element of the fourth planetary gear device, and wherein the second rotary element of the fourth planetary gear device is continuously connected to the output shaft.