换向阀异常打开故障分析与改进

针对某型号2D换向阀在使用中出现的未供电异常打开故障，建立故障树。应用故障件失效分析方法进行了故障定位、机制分析和故障复现试验，确认故障原因是油液中析出的气体进入2D换向阀的敏感腔，降低了敏感腔内油液体积弹性模量；当向2D换向阀供油时，2D换向阀的高压腔压力比敏感腔压力建立快，导致阀芯移动超过失效临界位置，使敏感腔与回油腔连通，阀芯保持在极限打开位置。依据分析结果对2D换向阀端盖增加了限位措施。经试验验证，该措施有效。

Fault Analysis and Solution for Abnormal Opening Failure of 2D Directional Valve

Fault tree was established for abnormal opening failure of a certain type of 2D directional valve during using without power supply. Using the failure analysis method, the fault location and fault cause analysis were carried out, and the fault recurrence test was carried out. The cause of the fault is that the gas precipitated from the oil enters the sensitive cavity of the 2D directional valve, which reduces the volume elastic modulus of the oil in the sensitive cavity; when supplying oil to the 2D directional valve, the pressure of the high-pressure chamber of the 2D directional valve is established faster than the pressure of the sensitive chamber, causing the spool to move beyond the critical position of failure, so the sensitive chamber is connected to the oil return chamber, and the spool is kept at the limit position. Based on the analysis results, limit measure was added to the end cap of the 2D directional valve. The test proves that the measure is effective.