當我們聽到升降機有噪音時，第一先要檢查閥門、馬達、液壓泵、固定安裝等方面的因素導致噪音產生。 如果在更換液壓油的時候，因為操作的不謹慎，會導致液壓缸中進入空氣，當升降機有高壓時會產生氣穴，使液壓缸產生噪音。
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過緊，也會產生大的噪音，不過磨合一段時間就沒有問題了。液壓油不足時，液壓泵產生吸空，將空氣吸入到液壓油中，這樣也會導致液壓升降機高噪音的產生。
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. 

如果液壓油吸入空氣或者溢流閥卡住，或升降機磨損比較嚴重時，會引起溢流閥調壓不穩以及卸壓時間太短等問題，這些問題間接導致溢流閥先導閥性能不穩，導致噪音產生。
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.