Abstract: As an important electro-hydraulic control element, proportional flow valve can continually control the speed or rotation rate of actuators according to the setting signal, which has been widely used in all kinds of electro-hydraulic system. In order to eliminate the influence of variety of load pressure on the flow rate, the traditional electro-hydraulic proportional flow valve needs to use pressure difference compensator or flow sensor, which will increase the complexity of the valve and the volume of valve structure, and cause the additional throttling loss. In order to solve these problems, according to the flow amplification characteristics of Valvistor valve, a new-type proportional control principle based on pressure variation-displacement correction of pilot flow and flow amplification of main valve is proposed. The pilot valve spool displacement is adjusted in real time according to the pressure difference of the pilot valve detected by the pressure sensor according to the method. In this paper, the mathematical model of the new-type proportional flow valve is established, and the control strategy based on compensation principle is derived. Then the simulation model of the valve is established, and the static and dynamic characteristics with and without compensation of the proportional flow valve are analyzed. The test prototype is designed and manufactured, and the feasibility of the proposed method is validated by experiments. The test results show that the proposed principle can eliminate the influence of the variety of main valve port pressure difference on the output flow, the dynamic response is fast, which is especially suitable for the electro-hydraulic flow control in large flow conditions.

Key words: proportional flow control valve, Valvistor, variety of pressure difference-displacement adjustment