Research On The Structure Design And Characteristics Of Valve Port Pressure Difference Continuous Controllable Multi-way Valve

In the hydraulic system of construction machinery,the multi-way valve is responsible for the important responsibility of flow distribution and is the key control core of the construction machinery.According to different structures,multi-way valves are divided into two types: with pressure compensator and without pressure compensator.In order to accurately distribute the flow,in the load sensing system,a multi-way valve with compensator is used.However,the pressure compensator is affected by factors such as hydraulic power and spring force,resulting in low flow control accuracy of the multi-way valve.Moreover,the pressure difference of the main valve of the multi-way valve is uncontrollable,and it is difficult to control the small flow rate.In response to the above problems.This dissertation proposes the compensation pressure difference control technology.Apply additional force to the compensator spool.It can not only control the main valve pressure difference,reduce the pressure difference to improve the micromotion characteristics of the multi-way valve,and increase the pressure difference to achieve the rapid response of the actuator.It can also compensate for disturbance factors such as hydraulic power and spring force,optimize flow control characteristics,and improve control accuracy.Based on the pressure difference control technology,an electro-mechanical pressure difference control unit composed of a servo motor and a ball screw is designed.Add it to the pressure compensator to design a new type of pressure difference controllable multi-way valve.In the pre-valve compensation system and the post-valve compensation system,theoretical analysis and simulation research are carried out.The research content is as follows:Firstly,select the scheme,select and check the motor and screw.Completed the derivation of the formula for the flow area of the UUU throttle groove.The structure design and threedimensional model of the new pressure difference controllable multi-way valve are carried out.In the post-valve and pre-valve compensation systems respectively,the working principle of the new type of pressure difference controllable multi-way valve is studied.Secondly,the mathematical model of the new type of differential pressure controllable multi-way valve was completed.Established the mathematical model of the electro-mechanical pressure difference control unit.In addition,the steady-state motion equation of the main valve and the mathematical model of the pressure compensator are establishedFurthermore,in the Simulation X software,the simulation model of the original valve of the multi-way valve is completed.The test bench was built and the multi-way valve bench test was carried out.The pressure and flow characteristics are compared with the test results,and it is concluded that the simulation model is correct.Finally,in the Simulation X simulation platform,two co-simulation models of the pressure difference controllable multi-way valve with post-valve compensation and pre-valve compensation were built.The simulation study of pressure difference control characteristics,hydraulic power and spring force compensation is carried out.And under the control state and non-control state of the electro-mechanical pressure difference control unit,the influence of the structural parameters of the motor and the lead screw on the dynamic response of the compensator and the pressure difference control characteristics is simulated.Research indicates: The new pressure difference controllable multi-way valve can continuously control the pressure difference of the main valve orifice according to the requirements of the working conditions.Moreover,the hydraulic power and spring force can be estimated and compensated,which improves the accuracy of flow control.In addition,when the electro-mechanical pressure difference control unit does not control and controls two states,when the servo motor’s moment of inertia is smaller and the ball screw lead is larger,the effect on the response characteristics of the compensator is smaller,and the pressure difference control dynamic response is better.