Design of Vehicle Track Adjustment Mechanism Based on Synchronous Valve

Abstract

Track adjustment mechanism of high frame vehicle is designed in order to meet the agronomic requirements of maize field management. track adjustment mechanism is designed using parallel four links, in which a rotating plate acting as connecting rod is hinged with hydraulic pushing rod, and wheel track is adjusted by stretching of the hydraulic pushing rod. In the adjustment process, synchronization of wheel track adjustment on both sides is ensured by hydraulic synchronization valve. The mechanics analysis method is used to analyze force of the wheel track adjusting mechanism, and the force of hydraulic cylinder is determined. Model of the track adjusting system is established by AMESim and dynamic simulation is carried out. Changes of pressure, flow and displacement of two hydraulic adjusting cylinders are analyzed. The simulation results show that pressure of two hydraulic cylinders appears small pulsates before t=3.45 s, it rises to the maximum of 20MPa at t=3.55 s and then stabilizes at 20MPa. Flow rate of the two hydraulic cylinders jumps up and down around 32.5 L / min before t = 3.45 s, the jump amplitude of hydraulic cylinder 1 is 10.7 L/min, the jump amplitude of hydraulic cylinder 2 is 3.0 L/min. Displacement of two hydraulic cylinders gradually increase before t=3.55 s, they reach the maximum value of 0.6 m at t=3.55 s and then stabilizes at 0.6 m. Displacement difference of two cylinders appears pulsation before t=3.55 s, it reaches 8.5×10-3 m at t = 0.21 s and stable in the vicinity of 0 m. The change of pressure, flow and displacement of hydraulic cylinders accord with design requirement, and the maximum displacement difference value of 8.5×10-3m can meet the agronomic requirement of high-stalk crops field management.