Design And Optimization For The New Rotary Buffering Control Valve With Resistance To Load-fluctuation

As an important equipment for carring loads, truck crane has the characters of high efficiency and flexibility, and is the essential equipment in engineering construction. As an important part in truck crane, hydraulic system has a great effect on the performance of truck crane. The hydraulic system of truck crane includes four parts, slewing, luffing, lifting and telescoping systems. As one of the most important hydraulic systems, slewing system plays a crucial role on the performance of the truck crane system. At present, many slewing control valves applied in the slewing hydraulic system of truck crane use bypass throttle form, however, most slewing valves of this form existed a problem that is the motor speed was affected by the load, what’s worse, when overloaded, the motor almost stopped, and the motor speed almost became0, and this situation is very dangerous in the process of construction. So, the research on the slewing control valve is very important to improve the performance of truck crane.This work studied a new slewing control valve applied in slewing hydraulic system, used the method of combining the simulation analysis and experiment test, and tested the steaty-state performance and the dynamic performance of the slewing control valve. Then we designed and optimized the throttling groove form, and made it match with the dynamic performance. And we put forward a new slewing buffering control valve, and tested its steady-state and dynamic performance based on the simulation model. Finally, we designed a new slewing control valve rod which is greatly optimized insufficiency in dynamic performance. The study in this thesis has important theoretic and practical significance to the design and development in slewing control valve applied in large inertia rotary hydraulic system.The major contents of this thesis are summarized as follows:In chapter1, firstly, the general situation, classification, and development trend of truck crane were introduced briefly, secondly, the present research status and characteristics of slewing hydraulic system on truck crane were presented, last, the background, research consent and significances of this topic was pointed out.In chapter2, a new slewing control valve with resistence of load-fluctuation was introduced firstly, and the structure and principle of it were presented.In chapter3, based on the AMESim platform, we established simulation models of the slewing valve and the whole hydraulic system. And we improved the simulation model by using the experiment data, through analysis and comparision, we got preliminary conclusions.In chapter4, the test-bench of large inertia slewing valve was introduced firstly, through simulating the real vehicle experiment condition, we verified the results of optimization and tested the steady-state and dynamic performance of the new designed valve spool. Then the real vehicle test was conducted to verify the optimization solution.In chapter5, on the basis of the accurate simulation model, we analyzed the problems of the pressure impact and fluctuation in the dynamic performance of the slewing control valve, and proposed optimizing plan.In chapter6, in order to test the practical application of the new valve with resistence of load fluctuation, we coorperated with a company who offered a30t truck crane, and worked out a real-vehicle test plan to test the dynamic and the steady-state performance and the stability of little-opening motor flow.In chapter7, the main research work and achievements were summarized, and the future study suggestions were provided.