Design And Research On Hydraulic System Of Folding Arm Type Truck Mounted Crane

Folding-jib lorry loading crane can carry the materials around the truck in a small range, when it works, the hook lifting and laying down through each arm's joint actions is directly connected with a weight. Because of the characteristics of the crane with multiple operations and compound actions, it should be given a high requirement for the stability and control of the hydraulic system.This paper starts with overall system design, different hydraulic systems are analyzed and compared, the overall scheme that is valve after the pressure compensated load sensing system is established. The principle of folding-jib lorry loading crane's hydraulic system is introduced, and the proper order way of controlling in hydraulic circuit of telescopic boom. For the main parameters of the load sensitive system of valve post pressure compensation, the parameters matching is carried out by simulation. Finally, the problems of flow saturation, compound actions and over flow matching in multi-actuator load sensitive hydraulic system are developed. The main tasks of this research are as follows:(1)According to the task demand of folding-jib lorry loading crane hydraulic system, a scheme which using valve post pressure compensated load sensitive control system is put forward. The hydraulic system of folding-jib lorry loading crane is designed, and the proper order way of controlling in hydraulic circuit of telescopic boom.(2)In the folding-jib lorry loading crane hydraulic system, load sensitive(LS)system is taken as the model of study, and the main structure and working principle of load sensing control system is analyzed. The mathematical model of load sensing pump is established. Through modeling and simulation based on AMESim, The effect of the main parameters of load sensing pump on the dynamic characteristic of the whole hydraulic system is studied. Finally, the best matching parameters are obtained, which can improve the stability and reduce noise to the system(3)Taking valve post pressure compensated load sensitive control system as object of study, control principle and characteristic of LUDV multi-way valve is studied and simulation model of AMESim is established. The characteristics of dynamic, anti-flow saturation, load independent flow assignment and energy-saving based on the valve post pressure compensated load sensitive control system under typical working conditions are studied.(4)Valve post pressure compensated load sensitive control system of folding-jib lorry crane is optimized. Considering the special circumstance that may lead to system pressure rise suddenly, based on the valve post pressure compensated load sensitive control system, the flow unloading valve is jointed and its working principle is analyzed. Finally, pressure and flow characteristics simulation in the hydraulic system are conducted, at the same time energy saving is proved.