旋转冲击作用下凿岩机水封密封性能分析*

为探讨液压凿岩机冲洗机构水封在高频冲击和旋转运动复合作用下的泄漏情况,在分析钎尾冲击速度随时间变化规律基础上,通过求解广义雷诺方程分析密封区的流体力学特性,建立旋转冲击复合作用下凿岩机水封密封区膜厚及泄漏量的计算模型。基于ABAQUS分析冲击周期内变速度下的水封接触应力变化规律,分析不同流体压力、冲击速度幅值和转速对密封性能的影响。结果表明:最大接触压力的变化和内外行程有关,外行程最大接触压力随冲击速度幅值的增大而增大,随转速的增大而减小,内行程则相反;同时无转速时的最大接触压力明显小于有转速时的最大接触压力,外行程的整体的最大接触压力大于同位置内行程的最大接触压力;冲击速度幅值越大,一个周期内的实时泄漏量和净泄漏量越大;不同转速下的实时泄漏量比较接近,转速越大,净泄漏量越小,表明在一定的范围内提高转速有利于提升水封密封性能;随液体压力增大最大接触压力变大,实时泄漏量变小,而净泄漏量先变小再变大,表明在中等压力下水封的密封性能更好。

Analysis of Water Seal Leakage of Rock Drill under Rotating Impact

In order to investigate the leakage of the water seal of the flushing mechanism of the hydraulic rock drill under the combined action of high frequency impact and rotational motion,on the basis of analyzing the variation of the impact velocity of the drill tail over time,the hydrodynamic characteristics of the sealing area were analyzed by solving the generalized Reynolds equation,and the calculation model of film thickness and leakage of the water seal area of the rock drill under the combined action of rotating impact was established.Based on ABAQUS,the change law of the contact stress of the water seal under variable speed in the impact cycle was analyzed,and the influence of different fluid pressure,impact velocity amplitude and rotation speed on the sealing performance was analyzed.The results show that the maximum contact pressure change is related to the inner and outer strokes.For the outer stroke,the maximum contact pressure increases with the increase of the impact speed amplitude,and decreases with the increase of the speed.While the inner stroke is opposite.The maximum contact pressure without rotating speed is obviously less than that with rotating speed,and the overall maximum contact pressure of the outer stroke is greater than that of the inner stroke at the same position.The greater the impact speed amplitude,the greater the real time leakage and net leakage within a cycle.The real time leakage rate is relatively close at different speeds,and the greater the speed,the smaller the net leakage,indicating that increasing the rotating speed in a certain range is beneficial to improve the sealing performance of water seal.As the liquid pressure increases,the maximum contact pressure becomes larger,the real time leakage decreases,and the net leakage first decreases and then increases,indicating that the sealing performance of water seal is better under medium pressure.