Clutch Control Study Of Hydro-mechanical Variable Transmission Based On The Electro-hydraulic Proportional Buffer Valve

Hydro-mechanical continuously variable transmission(HMT) is a kind of double power flow transmission with high efficiency and continuously variable speed, and is a ideal transmission in heavy vehicles. The shift quality is the key to further development of HMT. There was an impact in HMT power shift, and research results showed that controlling the pressure of the wet clutch could effectively improve the power shift quality.This paper takes the two-range Hydro-mechanical continuously variable transmission as the research object. Based on the modeling, simulation and experiment, the electro-hydraulic proportional buffer valve was designed, and its oil pressure buffer characteristics was researched. The main contents are as following: Analyzed the theory of electro-hydraulic proportional buffer valve and took it as the priority valve of the system. According to characteristic of the wet clutch, the parameters of buffer valve was calculated and the structure was designed; The simulation model of electro-hydraulic proportional buffer valve was established, analyzed the influence laws that the pressure with control signals and pressure with the structure parameters of buffer valve, from this the structure parameters of buffer valve was optimized. Established the experiment platform and studied the experiment of electro-hydraulic proportional buffer valve. The outcome of the experiment showed that the buffer pressure law of tested valve in line with the simulation. and proved the validity of the valve parameter and simulation.