Design And Simulation Of On-board Hydraulic Power System Based On Load Sensitivity Principle

With the rapid development of science and technology,mobile equipment has put forward higher technical requirements for hydraulic power system.The efficiency of traditional vehicle-mounted hydraulic power system is low,and the classical mechanical transmission is not flexible enough,so it is difficult to be applied in special fields.Therefore,the research of high stability,high efficiency and high precision vehicle-mounted hydraulic power system has become an urgent problem to be solved.Compared with conventional hydraulic system,load-sensitive hydraulic system has lower power loss and is widely used in various industries such as construction machinery,handling machinery and mining machinery.For the load-sensitive hydraulic system,the quantitative pump load-sensitive hydraulic system has better stability,but there is flow loss,low transmission efficiency,and the variable pump load-sensitive hydraulic system can reduce the system heat,but the system stability is poor.In order to solve the above problems,the main research work of the thesis is as follows:(1)A vehicle-mounted hydraulic power system based on load-sensing principle is designed.The system uses the proportional variable pump,according to the requirements of working conditions,real-time adjustment of the input signal of the proportional variable pump,when the input signal is unchanged,equivalent to the quantitative pump to the load sensitive system oil supply,integrated the stability of the quantitative pump load sensitive system and the advantages of variable pump load sensitive system energy saving.The composition and working principle of the vehicle-mounted hydraulic system are analyzed,the design calculation and selection of the main components of the vehicle-mounted hydraulic system are completed,and the practical application of load-sensing technology in the vehicle-mounted hydraulic power system is studied.(2)In order to provide theoretical basis for system simulation,the system transfer functions of proportional variable pump,pressure compensation valve,proportional reversing valve,hydraulic motor and swing attitude adjustment hydraulic cylinder are constructed,and the mathematical modeling of the valve-regulated hydraulic motor system and the valve-regulated swing attitude adjustment hydraulic cylinder system was completed.(3)The Amesim simulation software is used to establish the simulation model of each component of the vehicle-mounted hydraulic power system,and the simulation model of the vehicle-mounted hydraulic power system based on the load-sensitive principle is established.The stability and power consumption of the load-sensitive hydraulic system which uses proportional variable pump,load-sensitive variable pump and quantitative pump respectively for oil supply are compared and analyzed.The influence of different load conditions on the speed of hydraulic motor,the influence of different opening size of proportional multiway valve on the speed and displacement of hydraulic cylinder and the three working conditions of the system are analyzed.(4)The vehicle hydraulic power system testing table was established based on the load-based sensitive principle of loading,and a sudden and reduced load test of the generator,as well as the parameter testing of parking power generation,driving power generation,and hydraulic system.The test value of the vehicle hydraulic power system meets the technical requirements,and the system can run stably.