Characteristics Research On New Pilot Proportional Direction Valve Applying Flow Closed-loop Control Method

Electro-hydraulic proportional valve uses electro-mechanical conversion devices, which make the input electrical signal into a displacement signal, to achieve the control of the traditional industrial hydraulic valve and then to realize the control of the hydraulic system's parameters such pressure, flow direction and so on. Compared with the servo valve, electro-hydraulic proportional valve has energy consumption, low manufacturing cost and strong oil solution. Compared with the traditional hydraulic control valve, electro-hydraulic proportional valve has good control characteristics, quick response and the ability to continuously control the output pressure and flow.In this paper, electro-hydraulic proportional valve is analyzed in detail and a new type of pilot proportional directional valve is designed application of displacement-pilot flow feedback principle. The designed valve is modeled and simulated through Pro/E and SimulationX. The simulation results prove the feasibility of the application principle and determine the structure parameters of proportional direction valve. The detailed structure of the paper is listed as follow:1. Will electro-hydraulic proportional valve when as a miniature hydraulic system is studied. The relationship between various components and part of the overall impact are analyzed in depth, established mathematical models of proportional control unit, electro-mechanical conversion devices, pilot hydraulic half bridge and chamber.2. Research on the principle of displacement-pilot flow feedback principle, propose a new type of pilot proportional directional valve applying the control principle based on Bosch Rexroth multi-channel valve, design and calculate structure of some components'such as spool, throttle trough, valve cover, spring and so on.3. Using Pro/E software to establish three-dimensional model of the valve, determine its structure to meet the design requirements. Using SimulationX software to establish the hydraulic model of the valve, determine its working principle to meet the design requirements.4. Test the various characteristics of proportional direction valve through simulation experiment, and the simulation results show that the valve has high control accuracy, fast control precision, fast dynamic response and relatively high promotion value.