汽车起重机变幅系统抗冲击与微动性能研究

发布时间：2018-06-18 17:21

本文选题：汽车起重机 + 液压变幅系统　；参考：《浙江大学》2011年硕士论文

【摘要】：汽车起重机是一种广泛应用于建筑、道路、矿山等工程施工场所的工程机械,是工程起重机中最常用、最主要的机种。汽车起重机的液压系统主要包括上车液压系统和下车液压系统两大部分,其中上车液压系统由回转系统、起升系统、变幅系统、伸缩系统组成。目前国产起重机不同程度的存在在变幅下放时有冲击和抖动等问题,通过增加吊臂刚度可以减小吊臂的抖动幅度,但不能从根本上消除抖动。本课题以中联重科QY25汽车起重机为研究对象,采用理论分析,计算机仿真与实车试验和试验台试验分析相结合的方法,研究25t汽车起重机变幅下放存在的液压冲击及吊臂抖动问题,提高汽车起重机变幅系统的抗冲击和微动性能。本论文建立了汽车起重机液压系统核心元件的Amesim模型,结合多体动力学模型复现了汽车起重机液压系统存在的问题工况。在理论分析和仿真分析的基础上,提出了对变幅液压系统的改进方案,对核心液压元件多路阀、平衡阀结构进行了优化,并进行实车试验。消除了变幅下放过程中的液压冲击和抖动问题,降低了系统压力并改善了变幅系统的微动性能及操控性。本课题研究工作对我国汽车起重机提高抗冲击性能和多路阀、平衡阀的设计、开发具有重要的理论意义和工程应用价值。本论文的主要内容可分为6章,现分述如下：第一章,阐述了汽车起重机的液压系统组成、发展应用和国内外研究现状,提出了课题的研究意义和课题的主要研究内容。第二章,深入地分析了汽车起重机多路阀液压系统及存在的问题工况,重点针对多路阀的负载敏感、压力补偿、抗流量饱和和合流切换功能进行了分析。第三章,通过理论计分析并结合液压仿真提出了消除变幅下放液压冲击和吊臂抖动的改进方案,对多路阀及平衡阀阀杆进行改进,进行实车试验并采集试验数据,为进一步优化系统提供依据。第四章,针对改进后的变幅系统下放系统压力及背压偏高的问题提出了优化方案,对平衡阀、多路阀进一步优化并上车试验,试验结果表明优化方案降低了系统压力及变幅背压,提高了变幅系统性能。第五章,搭建多路阀、平衡阀液压试验台,对优化前后的核心元件进行动、静态试验对比,结果表明改进后的平衡阀能有效消除平衡阀开启、关闭滞后。第六章,概括了课题的主要研究工作和成果,并展望了今后需要进一步研究的工作和方向。
[Abstract]:Truck crane is a kind of construction machinery which is widely used in construction, road, mine and other engineering construction sites. It is the most commonly used and main type of construction crane. The hydraulic system of truck crane mainly consists of two parts: the hydraulic system and the hydraulic system. The hydraulic system is composed of rotary system, lifting system, amplitude changing system and telescopic system. At present, there are some problems such as shock and jitter when the amplitude of the crane is lowered. By increasing the stiffness of the boom, the jitter amplitude of the jib can be reduced, but the jitter can not be eliminated fundamentally. This subject takes the QY25 truck crane of Zhonglian heavy Branch as the research object, and adopts the method of theoretical analysis, computer simulation, real vehicle test and test bench test analysis. In order to improve the impact and fretting performance of a 25t truck crane, the hydraulic impact and jiggle of the jib are studied in order to improve the anti-impact and fretting performance of the luffing system of a 25t truck crane. In this paper, the Amesim model of the core components of the hydraulic system of truck crane is established, and the problems existing in the hydraulic system of the truck crane are reappeared in combination with the multi-body dynamics model. On the basis of theoretical analysis and simulation analysis, an improved scheme of amplitude varying hydraulic system is put forward. The structure of multi-way valve and balance valve of the core hydraulic component is optimized, and the actual vehicle test is carried out. The problems of hydraulic impact and jitter are eliminated, the pressure of the system is reduced and the fretting performance and maneuverability of the system are improved. The research work of this paper is of great theoretical significance and engineering application value for improving the anti-shock performance and the design and development of multi-way valve and balance valve for Chinese truck crane. The main contents of this paper can be divided into six chapters. The main contents are as follows: chapter one, the composition of hydraulic system of truck crane, its development and application, and the current research situation at home and abroad. The significance of the research and the main contents of the research are put forward. In the second chapter, the hydraulic system of multi-way valve of truck crane and its existing problems are deeply analyzed, and the functions of load sensitivity, pressure compensation, anti-flow saturation and combined flow switching of multi-way valve are analyzed. In the third chapter, through theoretical analysis and combined with hydraulic simulation, an improved scheme is put forward to eliminate the hydraulic impact and jiggle of the jiggle arm. The multi-way valve and the valve stem of the balance valve are improved, and the actual vehicle test is carried out and the test data are collected. To provide the basis for further optimization of the system. In the fourth chapter, aiming at the problem of high pressure and back pressure of the improved amplitude shift system, the optimization scheme is put forward. The balance valve and multi-way valve are further optimized and tested on the bus. The experimental results show that the optimized scheme reduces the system pressure and amplitude back pressure, and improves the performance of the amplitude change system. In chapter 5, the hydraulic test bench of multi-way valve and balance valve is built, and the dynamic and static test results of the core components before and after optimization are compared. The results show that the improved balance valve can effectively eliminate the balance valve opening and closing lag. In the sixth chapter, the main research work and achievements are summarized, and the future research work and direction are prospected.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：TH213.6

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