One of the basic parameters of the event pressure type hydraulic system, whether the event pressure is general or not will greatly affect the event function of the hydraulic system. The abnormal pressure of the hydraulic system is often manifested as the failure of the pressure regulating valve when adjusting the pressure, the failure of the system pressure to stand up, the complete absence of pressure, the continuous connection of high pressure, the pressure rising and falling down, and the unstable pressure.

Once the emerging pressure is abnormal, it will be difficult for the implementing elements of the hydraulic system to carry out the general cycle of things. They can emerge and remain in the original position. The speed of action is significantly reduced. When acting, the coherent control valve group often emits a harsh noise, which causes the machinery to be in an unusual condition and affects the use function of the whole machine.

1、 Hydraulic pump Hydraulic motor Reasons

1. The hydraulic pump and motor have been used for too long, the internal wear is severe, the leakage is large, and the volume effect is low, resulting in insufficient output flow of the hydraulic pump and low system pressure.

2. The engine speed is too low and the effectiveness is insufficient, resulting in the lack of system flow and the low pressure of the hydraulic system.

3. Orient the hydraulic pump to master the assembly position fault or assembly error, the pump is not working, and the system has no pressure.

2、 Reason of hydraulic control valve

1. In the process, if the pressure keeps rising and falling, many of them are the failure of the reversing valve, which causes the system to continue unloading or high pressure.

2. The damping hole of the overflow valve is blocked Hydraulic cylinder manufacturer Burrs on the main valve core, dirt between the valve core and the valve hole and clearance, etc. can make the main valve core stuck in the fully open position. The hydraulic oil output by the hydraulic pump directly returns to the oil tank through the overflow valve, and the pressure oil circuit is short circuited with the return oil circuit, forming a system without pressure; If the main valve core is stuck in a closed position by the above burrs or dirt, the system pressure will continue to be too high to drop; When the valve core of the overflow valve or the reversing valve emerges and is stuck, the valve core does not act naively, the implementing parts will emerge with signs of action but no action, and the pressure is unstable when detecting the system pressure.

3. For the system with check valve, if the deflection of the check valve is reversed, the system pressure will not rise.

4. Leakage in the system surface, such as serious leakage between the valve core and the valve body hole, will also cause the system pressure not to rise.

3、 Other reasons

1. Too low oil level in the hydraulic oil tank, too thin oil suction pipe, and clogged oil suction filter by impurities and dirt will lead to too large oil suction resistance of the hydraulic pump (when the hydraulic pump is empty, it is often accompanied by adverse noise), resulting in lack of system flow and low pressure.

2. In addition, when the oil return pipe is on the liquid level (foam occurs when the oil return hits the oil in the oil tank, causing a large amount of oil in the oil tank to mix into the atmosphere), the poor sealing of the oil suction pipe and air leakage easily form the atmosphere in the hydraulic system, resulting in unstable system pressure.