中小吨位汽车起重机液压工作回路仿真及实验研究

发布时间：2018-07-08 21:37

本文选题：汽车起重机 + 液压系统　；参考：《沈阳建筑大学》2011年硕士论文

【摘要】：汽车起重机是广泛应用于国民经济各领域的一种流动式起重设备。随着我国经济建设的发展,对其需求量越来越大,对其性能的要求也越来越高。回转机构和起升机构是汽车起重机重要的机构,其液压系统特性直接影响整个起重机的工作性能。目前,国内汽车起重机的制造厂商主要依据经验及类比的方法来进行液压系统的设计,再通过样机试验来发现问题。这既花费了大量的时间和精力,又增加了设计成本。本文首先对汽车起重机液压系统的组成及特点和液压仿真技术进行了介绍,阐述了液压系统仿真建模的几种方法,对汽车起重机回转机构、起升机构的液压回路进行了分析,简化出相应的液压系统原理图。其次,借助法国AMESim软件,分别建立了QY20汽车起重机回转机构和起升机构的机液一体化仿真模型,恰当选择了系统元件的子模型,通过现场实测验证了仿真模型的正确性。最后,设计了仿真实验,对回转机构的制动精度以及转动惯量、回转阻力矩、制动时间、换向阀阀口开度、溢流阀调定压力等因素对汽车起重机回转机构和起升机构液压系统的影响进行了分析。仿真结果表明,工作状态改变时,系统会产生压力冲击,而以上影响因素对回转机构和起升机构液压系统的压力冲击较为明显,在系统设计中必须合理匹配才能获得满意的系统动态特性。本文讨论了汽车起重机起升系统存在的二次下滑现象,阐述了解决二次下滑现象的基本途径,选取了将制动器油路中的单向节流阀的控制方式由手动控制改为液控,利用起升马达进、出油口的压力差来调整节流口通流面直径,间接控制制动器开启时间,从而达到消除二次下滑现象的最终目的。在此基础上,基于AMESim软件对改进后的系统进行建模仿真,利用仿真结果,给出了负载与起升马达建立所需压力的时间、制动器开启时间之间的对应关系,为通过改进单向节流阀内部结构来消除二次下滑现象并改善二次起升性能提供了方法和理论依据。这种基于仿真技术的系统分析方法对其它液压系统的设计研究具有借鉴意义。
[Abstract]:Truck crane is a kind of mobile lifting equipment widely used in various fields of national economy. With the development of China's economic construction, the demand for its performance is increasing. Rotary mechanism and hoisting mechanism are important mechanisms of truck crane, and their hydraulic system characteristics directly affect the working performance of the whole crane. At present, domestic truck crane manufacturers mainly design hydraulic system based on experience and analogy, and then find out the problem through prototype test. This not only costs a lot of time and effort, but also increases the design cost. In this paper, the composition and characteristics of hydraulic system of truck crane and hydraulic simulation technology are introduced, and several methods of simulation modeling of hydraulic system are described. The hydraulic circuit of rotary mechanism and hoisting mechanism of truck crane is analyzed. The schematic diagram of hydraulic system is simplified. Secondly, with the aid of the French AMESim software, the simulation models of the rotary mechanism and hoisting mechanism of QY20 truck crane are established, and the sub-models of the system components are properly selected. The correctness of the simulation model is verified by field measurement. Finally, the simulation experiment is designed for the braking accuracy, moment of inertia, torque of rotary resistance, braking time, opening degree of valve opening of reversing valve. The influence of the pressure adjustment of relief valve on the hydraulic system of the slewing mechanism and hoisting mechanism of truck crane is analyzed. The simulation results show that the pressure shock will occur when the working state changes, and the pressure impact of the hydraulic system of the rotary mechanism and the hoisting mechanism is obvious due to the above factors. In order to obtain satisfactory dynamic characteristics, it is necessary to match reasonably in the system design. This paper discusses the secondary sliding phenomenon in the hoisting system of truck crane, expounds the basic ways to solve the secondary slide phenomenon, and selects the control mode of the one-way throttle valve in the brake oil path from manual to hydraulic control. The pressure difference between the inlet and outlet of the hoisting motor is used to adjust the flow surface diameter of the throttle port and indirectly control the opening time of the brake so as to eliminate the secondary slide phenomenon. On this basis, the improved system is modeled and simulated based on AMESim software. By using the simulation results, the corresponding relationship between the load and the time required for the establishment of the lifting motor and the opening time of the brake is given. The method and theoretical basis are provided for eliminating the secondary sliding phenomenon and improving the performance of secondary hoisting by improving the internal structure of unidirectional throttle valve. The system analysis method based on simulation technology can be used for reference in the design and research of other hydraulic systems.
【学位授予单位】：沈阳建筑大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：TH213.6

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