The Research Of Speediness Discharge System Design And Test Of The Loader With Eight Poles

In this paper, the object of study is LIUGONG product 856â…¢wheel loader. The sum of time of the loader bucket lifting, unloading,and return to material stack is the smaller the better with not only this model, but also other models. So it will save a lot of time and improve work efficiency.Fast unloading system can be used not only in the eight-link loader, can also be used in other wheel loader.Because mechanical hydraulic system are universal in a certain sense. Fast unloading system can be applied to other engineering machinery, such as bulldozers, bucket before Boom also need the rapid decline with using similar principles. It can improve work efficiency greatly.In this article, I introduct the development of the loader, development trends briefly,and note the major part hydraulic system of the Loader. Loader has six-bar linkage and eight -bar linkage two agencies working device, and that there are positive and inversion two different connectivity forms for devices. The common link is six inversion and eight positive these two institutions. And now the target of paper is 856â…¢eight positive loader. This loader is a bit slowly when unloading.So the task of the paper is to solute this issue.The paper analysis the reasons for the 856â…¢eight Loader unloading with the slow speed.The reason is that the hydraulic system uses the original six-bar reversal agencies Loader hydraulic system,856â…¢loader uses eight positive agencies.It is to fight oil into the big cavity of the cylinder, when the bucket discharges, and the original six-bar reversal body cavity size loader when unloading oil from the contrary, but work pump and valve distribution linkage are the same as the six linkage.So eight linkage the large cavity enter the oil is smaller than the six-bar discharge to fight small cavity oil Relatively speaking reduced volume, when the loader bucket cylinder unloading ,at the same time the oil enter the big cavity to achieve maximum pressure lengthy, and the corresponding unloading speed is slower.We need design quick unloading system to solute the problem of slow, with the principle of the differential loop.We use the two-directional and the three openings hydraulic control directional control valve and user-friendly back-pressure valve. We will link the hydraulic control directional control valve cylinder size between the big and the small cavity of the bucket cylinder to connect the two cavities. That is, bucket cylinder can fight the hydraulic oil of the small cavity into the big cavity, to achieve the purpose of rapid discharge when discharges. A large number of formula applications in the analysis of the valve.Loader hydraulic system is the cylinder valve control system.We make the mathematical modeling for the system using the control principle, List reversing valve spool valve flow of the linear equation, hydraulic cylinder flow continuity equation, calculated the hydraulic cylinder of the balance equation and the transfer function, etc. We use theoretical analysis and calculation to the system, but also use software AMESim to simulate system.AMESim offers a time-domain simulation modeling environment, and establishments a new model components using the models have been used, constructs the actual prototype of the Optimization Design needs,with the easily identifiable standard ISO and multi-port diagram simple intuitive icons. The user can establishment complex system and the particular application examples friendly, modify model and simulation parameters, steady-state and dynamic simulation, analysis and mapping of simulation results.The operation is very convenient with the friendly interface. We use software components to Establish the structure of the whole system model, set the parameters of components in the model, and the actual application of numerical similar. We can use 3-D simulation of the software to see the model plans. RUN command of the software can simulate all kinds of curves we want. We can know the design system is improved with the design requirements or not by simulation both before and after improving system using AMESim, and comparing the two simulation results.Making comprehensive hydraulic test experiments to the two-directional three openings valve can test its Orifice pressure loss,oil-flow performance and dynamic characteristics by connecting valves'three mouthes to the test bed pressure sensors and flow sensors respectively, and setting the pilot pressure and the flow of the pump. It is necessary to test the valve open time and the close time because of the reduction valve spring . At last,we can get the result that the calve meet the actual needs.We install the two-directional and the three openings hydraulic control directional control valve in hydraulic system of the loader connecting between the big cavity and the small cavity of the bucket cylinder, at the same time install the 1.0 MPa back-pressure valve without the need fast unloading for user-friendly discharging slowly in the complete machine test and connect the big and small cavity of the bucket cylinder pressure sensors of the dynamic measurement instrument. Operating Loader to move Boom upgrade , the bucket unloading, or bucket and Boom decline several times,we can know the piston of the bucket cylinder extending and indentation only in the discharge and recovery the bucket. At this time we can get the relationship between pressure of the big cavity and the small cavity of the bucket cylinder and the time can be measured by dynamic measuring instrument. We can draw a conclusion by analysis the experimental results,and compare the experimental results to the actual working of the system without improvement to verify the feasibility of the improving system.