The Synthesis And Analysis Of Planetary Gear Transmission Mechanisms Of Multispeed Automatic Transmission

With the improvement of the quality of people’s living standards, the automotive plays an increasingly important role in people’s lives, and accordingly, the requirements for automotive performance also increase. Multi-gear automotive becomes the mainstream in the automotive area, Development of multi-gear automatic transmissions reflects the level of a country’s automotive industry to some degree. Because the automobile industry of our country starts late and the foundation is weak, most of the automatic transmissions is still dependent on importation. Domestic automotive companies still haven’t achieve a breakthrough in the field of high-tech multi-gear automatic transmissions. Based on this, the article presents a new integrated approach about the planetary gear mechanism of 8-speed automatic transmissions from the perspective of innovation. The kinematics and the dynamics of comprehensive results are analyzed afterwards, and then compared with the classical mechanisms.This article follows the studying procedure of mechanisms synthesis, geometrical compatibility verification, the analysis of kinematics and the analysis of dynamics. Considering the structural features and functions of the automatic transmissions, the planetary gear mechanisms are synthesized and selected based on the atlas database of planar 12-link 3-Do F topological graphs which has one multiple-joint. This article analyzes the three forms of mechanisms which consists of four planetary gear rows, according to the lever analogy. Then the planetary gear mechanisms which can realize 8-speed ratios theoretically are selected. Geometrical compatibility of the planetary gear mechanism is verified according to graph theory. Reasonable transmission scheme is designed according to the lever analogy and Matlab. Eventually, the new mechanism which can achieve 8-speed ratios is selected.Three-dimensional modeling and simulation of the new mechanism are finished by Solidworks. In order to verify the accuracy and reasonableness of the transmission scheme, kinematics and dynamic analysis based on the level analogy are introduced. Finally, the new mechanism is compared with classical transmissions on the efficiency, transmission ratio and step ratio in order to verify the feasibility.