当我们听到升降机有噪音时，第一先要检查阀门、马达、液压泵、固定安装等方面的因素导致噪音产生。 如果在更换液压油的时候，因为操作的不谨慎，会导致液压缸中进入空气，当升降机有高压时会产生气穴，使液压缸产生噪音。
When we hear the noise of the elevator, the first to check the valve, motor, hydraulic pump, a fixed installation and other aspects of the factors leading to noise generation. If the replacement of hydraulic oil, because the operation is not careful, will cause the air into the hydraulic cylinder, when the lift high pressure will produce cavitation, the noise produced by the hydraulic cylinder. 

使用新的密封圈或者密封过紧，也会产生大的噪音，不过磨合一段时间就没有问题了。液压油不足时，液压泵产生吸空，将空气吸入到液压油中，这样也会导致液压升降机高噪音的产生。
Elevator manufacturers analysis with a new sealing ring or seal tight, will also have a big noise, but in a period of time there is no problem. When the hydraulic oil is not enough, the hydraulic pump has suction, and the air is sucked into the hydraulic oil, which can cause the high noise of the hydraulic lift. 

如果液压油吸入空气或者溢流阀卡住，或升降机磨损比较严重时，会引起溢流阀调压不稳以及卸压时间太短等问题，这些问题间接导致溢流阀先导阀性能不稳，导致噪音产生。
If the elevator manufacturers analysis of hydraulic oil or air relief valve stuck, or lift more serious wear, will cause the pressure relief valve adjustment is not steady and the unloading time is too short and other issues, these problems lead to indirect pilot valve relief valve performance instability, resulting in noise.