Speed regulation is an important part of the hydraulic system. If the speed of the actuator is not normal, the hydraulic machinery cannot work.
The main failure of speed control system and its causes can be summarized as the following aspects
(1) the main reason why the actuator (hydraulic cylinder, hydraulic motor) has no small feed
1. The throttle of the throttle valve is blocked, resulting in no small flow or unstable small flow
2. The spring of the speed-regulating valve's differential pressure relief valve is too soft, which makes the pressure difference between the throttle valve front and back too low, leading to the instability of the small flow through the speed-regulating valve.
3. The pressure relief valve in the speed regulating valve is stuck, causing the pressure difference between the front and back of the throttle valve to change with the external load
(2) the main reason for the significant decrease of feed rate when the load increases
1. The leakage of hydraulic cylinder piston or one or more components in the system increases significantly with the increase of load and pressure.
2. The pressure reducing valve in the speed regulating valve is stuck in the open position, so the flow through the throttle valve decreases when the load increases
(3) the main reasons for the crawling of the executive mechanism
Enter air into the system
2. Due to lead to bad lubrication, guide rail and the hydraulic cylinder axis is not parallel, piston rod sealing too tight, the piston rod bending deformation, lead to the hydraulic cylinder work trip friction caused by larger changes
3. In the oil inlet throttling speed control system, the hydraulic cylinder has no back pressure or insufficient back pressure, and when the external load changes, the cylinder speed changes
4. Hydraulic pump; The flow fluctuation is large, and the system pressure fluctuation is large due to the vibration of the overflow valve
5. The valve port of the throttle valve is blocked, the system leakage is not stable, and the pressure reducing valve in the speed regulating valve is not flexible, resulting in unstable flow and creeping.