Research on Transmission Performance of A Seven-gear Three-degree-of-freedom Planetary Gear Automatic Transmission Based on Graph Theory and Matrix Equation

Abstract

The transmission performance analysis of planetary gear automatic transmission is helpful for the following structural size optimization, hydraulic design and electric control design. The current graphic method has the disadvantages of low calculation accuracy and lack of intuition in numerical analysis method. This paper proposes a method to analyze the transmission performance based on graph theory and matrix equation. Firstly, a graph theory analysis model is established for the self-designed seven-gear three-degree-of-freedom planetary gear automatic transmission, and the structural characteristics of the transmission are analyzed. Then, on the basis of analyzing the shift actuator worksheet, the motion analysis model and torque analysis model of typical gears are designed by taking the first gear and the reverse gear as examples, and the speed and torque values of all gears of the transmission are calculated by using the corresponding matrix equation. Finally, the power flow diagram of the typical gear is established by taking the first gear and the fourth gear as examples, and the direction and numerical value of power flow are identified on the diagram. The results show that the method can realize the combination of qualitative and quantitative analysis for the transmission performance analysis of the planetary gear automatic transmission with multiple gears and multiple degrees of freedom, which is more intuitive, accurate and efficient.