Simulation Research On Hydraulic System Of Truck Crane Lifting Mechanism

The lifting mechanism of an automobile crane is a particularly important part of many subsystems.Its work is responsible for the lifting and lowering of the load.The hydraulic control part of the lifting mechanism directly affects the entire truck crane in the working state.The characteristics of the hydraulic system are an indispensable reference for the performance of the whole machine.In order to pursue more excellent products,all manufacturers focus on the dynamic characteristics of the hydraulic system to upgrade the performance of the crane.Therefore,the research of this thesis has certain help and significance for the upgrade of the performance of the crane.Because a small and medium-sized truck crane will shake when the load decreases,when the load rises again,there will be a brief drop in the load.This article aims at the two phenomena that often occur in the field,so that the hydraulic system of the lifting mechanism has been optimized,and in order to optimize the working status of the hydraulic system,this paper has completed the following work.Firstly,this paper studies the principle of the lifting part of a truck crane.This part of the hydraulic system is simply classified and the differences in the loops of various systems are studied and analyzed.The relationship between the balancing valve and the brake cylinder in the system is studied and analyzed.The influence of the different opening times of the two systems on the system was designed and the damping network in front of the balancing valve was designed.Secondly,the internal structures of several key hydraulic components such as balancing valves were studied,the mathematical model was established,the AMESim software was studied,and the HCD simulation model was built through the HCD library and the performance of the valve was verified.At the same time,the performance of the brake element HCD simulation model was built and verified.Thirdly,AMESim software completes the model building work of the hydraulic system before optimization,and sets several working conditions that often appear in the actual work in advance,such as load mutation conditions,load reduction conditions,and secondary lifting conditions.In these conditions,the simulation work was completed.Based on the simulation results obtained,two problems existed in the hydraulic system before optimization: the jitter of the load drop and the momentary decline when the load was lifted again.Finally,by summarizing and analyzing the above work,the original system has been optimized accordingly.When the system has a situation of falling jitter,a damping network is designed to be placed in front of the balancing valve.The damping consists of a C-type half-bridge and a one-way valve.The two are connected in parallel and can be known from the optimized system simulation results.This method makes the problem of descent jitter effectively improved;faced with the problem of load shedding,another damping network is designed to be placed in front of the brake cylinder.The damping network is connected in parallel with the one-way valve after the two dampers are connected in series.According to the optimized system simulation results,it can be known that this method makes the load reduction problem better.