也谈液控单向阀卸载动态

DYNAMIC UNLOADING TEST OF HYDRAULICALLY OPERATED NON RETURN VALVE

通过对液控单向阀做各种卸载动态试验，并对测试曲线进行了分析，发现液控单向阀卸载液压谐振的根本原因，不是立柱积存大量能量突然释放必然引起的，也不是立柱缸筒弹性变形能全部转化为液压能，产生液压升高迫使阀芯向关闭方向运动引起的，而是处于瞬态力平衡状态的顶杆打开单向阀时，喷射出高速液体的动量变化使顶杆后坐，造成单向阀突然关闭引起的．它不是单一的水锤冲击，而是单向阀后管路中液体、单向阀、顶杆及其前后管路中液体参与影响。

The curves of various dynamic unloading tests of hydraulically operated non return valves were studied. It was found that the reason for hydraulic harmonic vibration of non return valve was not induced by sudden release of energy in the leg, nor by movement of spool towards the closing direction by the increased pressure due to insufficient conversion of elastic deformation energy into hydraulic enerfy. However, when the poppet which is in instantaneous balance state opens the check valve, the change of momentum of high speed hydraulic fluid jet makes the poppet move backward, which causes sudden close of the check valve. It is not only a single hammer effect, but it is a homonic vibration of the complete system including multiple hammer effects produced by fluid in the pipeline behind the valve, non return valve, poppet, and the fluid in front of and at the back of valve and poppet.