Design of A Planetary Gear Mechanism of A Seven-speed Automatic Transmission Based on the Lever Method

Abstract

Abstract The existing six-speed automatic transmission of Toyota AB60E has the shortcomings of large number of transmission actuators and complicated structure. The paper first uses the lever method to analyze the lever diagram of each gear of the transmission. And then, based on the six-speed automatic transmission of Toyota AB60E, a new seven-speed automatic transmission is designed. The lever method is used to analyze the speed of each component of the newly designed one and the relative speed of its shift actuators and planetary gears. Finally, the external torque of the device and the internal torque of each component are calculated. The results show that, with the same structure parameters of the planetary row, the number of shift actuators of the new transmission decreases to 6 and the gears increase to 7. The transmission ratio between gears is closer, and the overall performance is better than that of the transmission of AB60E. The automatic transmission of planetary gears can be designed quickly by the lever method, and the kinematics and dynamics analysis can be carried out.