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The paper studies the QY20 truck crane slewing mechanism hydraulic system and expounded its working principle. The models of slewing mechanism were built by AMSim and the model of buffer oil compensating valve was built by the HCD function of the software. The correctness of the models were validated by in-situ measurement. Influence factors of slewing mechanism dynamic characteristics about the models were analyzed.

The heading machine is one of the key equipment of coal mine roadway drivage, and cantilever machine applied most widel, A lot of coal roadway floor condition is very poor in our country, so its travel mechanism performance also have a higher requirements. Especially when driving on slopes, frequently, caterpillar not firm grip, and backward. This article is based on crawler and the ground interaction theory optimization model is established, the crawler structure parameters are optimized in order to obtain maximum tractive force,thereby improving the performance of walking.

Turntable is the main bearing component of truck crane, its structural-load-carrying capacity influences the operational capability directly. This paper adopts the HyperWorks software to make topology optimization for the turntable structure of QY70G truck crane, and carry out the finite element analysis and comparison for the models before and after optimization, which provides an effective method to improve the turntable structure of truck crane. Turntable is one of the important components of truck crane，it bears hoist boom、lifting、luffing mechanism and bob-weight and so on, it is the transfer center of truck crane when it works, the structure will directly affect the lifting performance of the machine. But, the rotary table structure design is affected by the vehicle shape size and installation and space layout. The traditional design method is based the experience of analogy to check by finite element software, it is difficult to get the design scheme which meets the requirements given above and own better strength and stiffness, it also have the disadvantages of long design cycle and large workload. This article is based on the finite element method and structural topology optimal idea, by means of HyperWorks-OptiStruct, makes finite element analysis for the turntable structure of certain QY70G truck crane, and carries on the structural topology in the condition of setted installation location and space, in order to obtain the ideal design plan.

This paper is made from a certain type of truck crane hydraulic lifting mechanism system as an object, then the second lifting working condition is analyzed. With AMESim, according to the hydraulic system diagram building lifting mechanism hydraulic system simulation model, hereby corresponding simulation conditions is set and the effects of secondary slide response on input signal, hoisting load, discharge and speed of pump, fluid resistance of one-way throttle is studied. This research on truck crane hoisting mechanism hydraulic system provides the theory basis for the design improvement, the relevant research methods and means have reference on the research of other engineering machinery hydraulic system working characteristics.