双缓冲腔环形间隙对凿岩机缓冲系统动态特性的影响

分析了液压凿岩机双缓冲系统的结构特点，应用孔口节流理论确定了缓冲活塞的静平衡位置，基于应力波传递原理得到了缓冲活塞的回弹速度，考虑油液的压缩特性推导出一级缓冲腔压力公式，由间隙流量公式得到了二级缓冲腔压力，在此基础上建立了缓冲活塞的运动微分方程.应用Matlab工具对双缓冲系统的动态特性进行了仿真，分析了不同环形间隙下缓冲活塞的运动规律，探讨了环形间隙对一级和二级缓冲腔压力的影响.提出与环形间隙和活塞最大行程的比值相关的间隙行程系数η.仿真结果表明，间隙行程系数与双缓冲系统的特性密切相关，存在最优范围.搭建了实验台，通过实验对缓冲系统的数学模型进行了验证.

Effect of annular clearance inside the double damping chamber on the dynamic characteristics of a rock drill damping system

The structure characteristic of the double damping system in a hydraulic rock drill was analyzed. The static balance position of the damping piston was determined by using the orifice flow law. The rebound velocity of the damping piston was derived from the transmitting principle of stress waves. The pressure equation of the 1st order damping chamber was deduced by considering the compressibility of hydraulic oil. The pressure of the 2nd order damping chamber was gained according to the equation of clearance flow rate. The motion differential equation of the damping piston was established based on these above foundations. The dynamic characteristics of the double damping system were simulated in Matlab. The movement laws of the damping piston were analyzed in different annular clearances. The relationships between annular clearance and the pressure in the 1st order and 2nd order damping chambers were discussed. The clearance-stroke coefficient was proposed,which was related to the ratio of annular clearance to maximum damping piston stroke. Simulation results show that the clearance-stroke coefficient is closely related to the damping system characteristics and has an optimal range. The mathematical model of the damping system was verified on the test platform.