Abstract:The dynamic characteristics and shift response of power shift transmission of cotton picker are the key factors affecting the shift quality of cotton picker. Taking a cotton picker power shift transmission as the research object, a performance research method of cotton picker power shift transmission was put forward based on Amesim mechanical-hydraulic coupling simulation and bench test. Firstly, based on the mechanical transmission structure and hydraulic system principle of power shift transmission, the simulation model of the power shift hydraulic coupling system of the cotton picker was constructed. Secondly, a comprehensive test bench of power shift transmission of a coton picker was designed and built, which realized the real-time acquisition of input and output speed, torque, and shift oil pressure of the power shift transmission. The accuracy of the simulation model was verified by comparing the transmission ratio change and shift oil pressure response between simulation and test under typical working conditions. Finally, a three-factor and three-level orthogonal test was used to quantitatively analyze the significance of the influence of input speed, load torque, and main oil pressure on the maximum impact degree of the output shaft and shift steady-state time. The results showed that the dynamie response trend of power shift transmission simulation was consistent with that of bench measurement. The amalysis of range and variance of orthogonal test showed that the oil pressure of main oil circuit was the most significant factor affecting the maximum impact degree of output shaft, while the speed of input shaft was the most significant factor affecting the steady-state time of shifting. To consider shifting speed and smoothness, the oil pressure of the main oil cireuit should be increased at the initial stage of shift to shorten the engagement time, and the oil pressure rise rate should be reduced in the middle and late stages of shift, to suppress the impact of the output shaft and realize the balance optimization of shift time and impact degree. The research results can provide a reliable theoretical basis and test platform support for performance prediction and control strategy optimization of the power shif transmission of the cotton picker.
