双面回油型液压凿岩机空穴及气蚀机理

发布时间：2018-02-12 09:14

本文关键词： 液压凿岩机双面回油型冲击机构活塞回弹机理实验空穴　出处：《煤炭学报》2016年S2期 　论文类型：期刊论文

【摘要】：具有双面回油型冲击机构的液压凿岩机,其能量利用率高,但活塞回程制动阶段的前腔负压常常造成活塞和前导向套的严重气蚀,影响了凿岩机的正常使用。阐明了双面回油型冲击机构的工作原理,考虑油液压缩、油液泄漏和活塞的撞击回弹等因素,建立了冲击机构的数学模型,并进行数值仿真。通过凿岩机机理实验,测试了活塞前、后腔压力和冲击频率,得到了活塞的冲程末速度。比较实验与仿真结果,验证数学模型的正确性。在此基础上,通过仿真获得了阀芯与活塞的位移曲线和速度曲线,确定了阀芯开始换向、经历负开口区间以及换向完成的准确时间点。给出了活塞前、后腔和左、右阀腔的压力变化规律,揭示了前腔空穴的产生机理。为此设计并加装了回油蓄能器,分析了不同的充气压力对前腔空穴的影响。仿真结果表明,回油蓄能器能够在一定程度上改善前腔负压问题,且在0 MPa的充气压力下,效果最佳,负压的持续时间将减半。
[Abstract]:Hydraulic rock drill with double-side oil return impact mechanism has high energy utilization ratio, but the negative pressure in front cavity of piston return braking stage often results in serious cavitation erosion of piston and front guide sleeve. The normal use of rock drill is affected. The working principle of double-side oil return impact mechanism is expounded, and the mathematical model of impact mechanism is established considering the factors such as oil compression, oil leakage and piston impact rebound, etc. Numerical simulation is carried out. Through the mechanism experiment of rock drill, the pressure and impact frequency of front and rear cavity of piston are measured, and the stroke end velocity of piston is obtained. The comparison of experimental and simulation results verifies the correctness of the mathematical model. The displacement curve and velocity curve of the valve core and piston are obtained by simulation, and the accurate time points for the valve core to begin commutating, to go through the negative opening interval and to complete the reverse direction are determined. The pressure variation rules of the front, rear and left and right valve cavities of the piston are given. The mechanism of producing front cavity hole is revealed. For this reason, the oil return accumulator is designed and installed, and the influence of different inflatable pressure on the front cavity hole is analyzed. The simulation results show that the oil return accumulator can improve the negative pressure problem of front cavity to some extent. And the best effect is at 0 MPa inflating pressure, the duration of negative pressure will be halved.
【作者单位】：北京科技大学机械工程学院;
【基金】：国家高技术研究发展计划(863)资助项目(2011AA060401)
【分类号】：TD421.22

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