【作者】 张庚云；

【导师】 谷立臣；

【作者基本信息】 长安大学 ， 机械电子工程， 2007， 硕士

【摘要】 混凝土湿喷机是混凝土施工中广泛使用的一种工程机械,它能一次连续完成水平运输和垂直运输,效率高、节省劳动力、费用低。液压系统是混凝土湿喷机最重要的组成部分之一,其设计的正确及合理与否不仅对混凝土湿喷机的技术性能有很大影响,而且对混凝土湿喷机整机工作的安全性和可靠性也至关重要。混凝土湿喷机的换向系统必须在极短的时间内实现S管的换向动作,但这同时造成混凝土湿喷机在换向过程中的液压冲击。液压冲击不但产生噪声、引起振动,而且将降低混凝土湿喷机的使用寿命。从这个意义上讲,有必要对混凝土湿喷机液压冲击进行深入研究并找到降低液压冲击的办法。本文在样机试验的基础上,对混凝土湿喷机液压系统的液压冲击和混凝土喷射脉动现象进行了研究。首先阐述了液压冲击对混凝土湿喷机的危害以及对工程质量的影响,提出对液压系统的改进方案,详细分析了泵送过程和电液换向过程,找到引起液压冲击和脉动的根本原因(泵送速度与换向时间不匹配);然后分析了混凝土在输送管道中的流动状态与分配阀的动力学特性,得出混凝土湿喷机的泵送负载和摆动负载;最后应用功率键合图的方法分别建立泵送系统和分配系统的数学模型,并利用仿真软件Matlab/Simulink对其进行仿真研究,分析在不同的泵送速度(输入流量)和换向时间下液压冲击情况,并验证了理论分析的正确性。更多还原

【Abstract】 Wet spraying machine is a kind of construction machinery widely used in concrete construction, that can once finish competence transporting and vertical transportation in succession, with high efficiency, low workforce and expenses. The hydraulic pressure system is one of the most important components in the wet spraying machine, the design not merely having very great influence on technical feature of wet spraying machine, but also is essential to the security and dependability of working to the wet spraying machine complete machine. The directional shift system of the wet spraying machine must complete S tube’s shift operation in very short time, which may cause hydraulic impact at the same time during the operation. The hydraulic impact not only results in noises and vibration but also reduces the equipment’s life time. So speaking from this meaning, it is necessary to research the hydraulic impact in wet spraying machine and find method to reduce the hydraulic impact.On the basis of experiment with the sample of wet spraying machine, the hydraulic impact and pulsation in wet spraying machine is researched in this paper. Firstly, the paper expatiated the harm to wet spraying machine and influence on the quality of project, and put forward the modification scheme for hydraulic system. Pumping process and the course of electricity and liquid changes were analyzed in detail in this paper. The cause of hydraulic impact and pulsation (pumping rate and the response time of dividing system does not match) was found out. Furthermore, the paper analyzed the flowing state of concrete in conduit by rheology principle and dynamics of dividing system, and established the pumping load and switching load of wet spraying machine. Finally, it set up the complete mathematical model of pumping system and dividing system with the widely used software Matlab/Simulink. The displacement of the rod piston and the impact of hydraulic are analyzed in different input flow and different reversing time. And the reliability of theory analysis is further verified.更多还原