Structure Design And Characteristic Analysis On Hydraulic High Speed On-off Valve Based On PWM

With the development of computer technology and the increasingly wide range of applications in various fields, Digital electro-hydraulic control technology has become an important means to achieve mechatronics,and ideal method for hydraulic system to achieve high-speed, high-precision control,which has been widely used in important areas of automobile, metallurgy, mechanical engineering, aerospace and other. Research on high speed on-off valve is an important part of digital electro-hydraulic control technology, it is a key element to achieve a digital electro-hydraulic control. Its working principle is to generate suction by controlling solenoid based on a series of pulse signals, making the spool move quickly for forward and reverse. So as to achieve flow alternately turned on and off at the valve port function, it could achieve reliable digital electro-hydraulic control without D/A conversion interface. Especially in recent years, the development of engineering machinery has put forward higher technical requirements for the high speed on-off valve. The existing high speed on-off valve mainly exist the shortcomings of small output flow and slow response,which has restrict the application and development of the high-speed on-off valve to a certain extent.This paper treats the contradiction between the high speed on-off valve large flow and high response as the starting point, which can improve the response speed of the high speed on-off valve appropriately on the basis of guaranteeing big flow. As a starting point for the design of a new pulse-width modulated (PWM) high-speed switching valve, the valve adopts the secondary structure and achieves two-way control. The double nozzle flapper valve for Pilot stage, and the symmetrical cone valve structure for power main stage. The pulse width modulation type high speed on-off valve expected design to achieve the following technical indicators:Load flow rate greater than40L/min, The switching time of valve less than4ms.According to the design principle of high-speed on-off valve, this paper use CAD software to draw2D assembly drawing, to design and calculate the main structure parameters of preliminary; this paper use Fluent software for three-dimensional modeling of the main valve port channel and analyze the flow field characteristics, obtain the different valve opening of the flow pressure curve; based on the mathematic model of the high speed on-off valve, AMESim and MATLAB/Simulink is used to study the static and dynamic characteristics of high speed switching valve, this pape has analyzed the control pressure double nozzle flapper valve in different parameters of the step response、effects of different width of important parameters and the several high-speed on-off valve performance, which could provide a basis for the rational selection of the valve structure parameters.Through structural design and simulation analysis of the valve, It is concluded that the opening and closing time of the high-speed on-off valve designed are3.2ms and3.6ms respectively, no-load flow rate reaches more than50L/min, the simulation results achieve the expected target.