Research On Proportional 3-Way Pressure-Reducing Cartridge

The use of Electro-hydraulic Proportional Technology on construction machinery greatly improves its operation and automation. As the pilot stage of Proportional multi-valve, Proportional 3-Way Pressure-Reducing Cartridge provides pilot pressure to drive the main spool and so to control the flow rate.This thesis analyzes and researches the Proportional 3-Way Pressure-Reducing Cartridge. Such a cartridge used on truck crane was developed and some conclustion was made.The development of the cartridge includes design of proportional solenoid and design for structure of the valve.We use hydrodynamics to design the valve port, Structure Parameters and so on. The proportional solenoid was designed by setting up its magnetic circuit model and the particularity of proportional solenoid's Flux Leakage was taken into account. The simulation model of the proportional solenoid was established in Ansoft and parameters of the solenoid was optimized by Electro-magnetic simulation. Co-simulation using Ansoft and AMESim was used to establish the model of 3-Way Pressure-Reducing Cartridge controlled main spool and the influence of the parameters on the performance are given.A laboratory bench to test the valve's performance was established and the test software was compiled with Labview language. Trial-product was made and tested, the results showed that the performance of the Trial-product and the Bucher's product were similar and the simlation models were confirmed.Theoretical research includes the following parts:1) Transfer function of the 3-Way Pressure-Reducing Cartridge controlled main spool system was established and some key parameter was analyzed by the transfer function.2) Influencing factors of constant Force-stroke characteristic was analyzed.Those factors were divided into two parts,the internal parameters and external parameters and eachone's influence was analyzed. Contradiction between rated force and rated displancement was found.3) Fourier expansion to PWM wave indicated that the PWM wave with 50% duty ratio contains the largest alternating components,increasing or reducing the duty ratio would reduce the alternating components.4) A new method for flow force compensation by adjusting magnetic pole was proposed.5) Machining technologies of valve core and armature assembly were researched to simplify process and reduce the cost.The main content of this thesis could fall into seven chapters as the followings:In chapter 1, the history and current research status of Proportional 3-Way Pressure-Reducing Cartridge and proportional solenoid are introduced based on a lot of the publications and conference papers. Consequently, the goal of research and project are brought forward.In chapter 2, transfer function of the 3-Way Pressure-Reducing Cartridge controlled main spool system was established and some key parameters were analyzed by the transfer function.In chapter 3, expected performance of the valve was determined. The valve port and Structure Parameters were designed by hydrodynamics. Machining technology of valve core was researched also.In chapter 4, the soft magnetic materials for the solenoid was chosen and analyzed. The magnetic circuit model of the solenoid was established and the structure parameters were designed base on the model. Influencing factors of constant Force-stroke characteristic were analyzed as well.Study on PWM wave driving and its requirement to the resistance of the winding was made. Machining technology of armature assembly was researched also.In chapter 5, the simulation model of the proportional solenoid was established in Ansoft and Parameters of the solenoid was optimized on the model. Co-simulation using Ansoft and AMESim was researched and the model of of 3-Way Pressure Reducing Cartridge controlled main spool was established base on this.Then the key factors to influence the system's performance was studied. A new method for flow force compensation by adjusting Force-stroke characteristic was put forward and was confirmed by simulation. In chapter 6, A laboratory bench for the valve was designed and test software was compiled with Labview language. Performance of trial-product and the Bucher's product were similar and the simlation models were confirmed by the test.In chapter 7, some conclusions in this thesis were summarized and the future research proposals were suggested.