Is the temperature rise of the hydraulic system malfunctioning?

We all know that in order to reduce the pressure of the hydraulic oil radiator, a bypass valve and a back pressure valve are placed at its oil inlet. The bypass valve pressure is generally set to 0.45MPa. If the pressure of the hydraulic oil radiator exceeds 0.45MPa, the bypass valve will open, and some hydraulic oil will return directly to the tank without passing through the hydraulic oil radiator. The pressure of the back pressure valve is 0.25 MPa to ensure that the main circuit of the system has a certain back pressure, and then to avoid vacuum during the operation of the hydraulic system, to ensure stable oil return, so as to avoid excessive oil return impact from damaging the hydraulic oil radiator.

　　 When the oil temperature of the hydraulic system of the excavator is slightly high, check whether the bypass valve and the back pressure valve are malfunctioning. If the bypass valve is normally open or the back pressure valve is closed, the hydraulic oil flows back to the hydraulic oil tank without being cooled by the hydraulic oil radiator, and the hydraulic oil temperature is too high.

In addition, the gap between the valve stem and the valve hole of the multi-way valve is too large, the gap between the plunger and the cylinder of the pump and the motor is too large, or the gap between the valve plate is too large, the hydraulic cylinder seal ring is worn and the gap is too large, and the end face of the pilot gear pump gear If the gap between the tooth tips is too large, severe internal leakage can be formed. When the oil leaks, its pressure energy will be converted into heat energy, resulting in an increase in the temperature of the hydraulic oil, resulting in a high temperature in the hydraulic system.

　　 If the pressure adjustment of the relief valve, hydraulic system pump and safety valve is unreasonable, it is easy to cause the hydraulic system temperature to be too high. If the system pressure is adjusted too high, it will cause the pump to run at a pressure exceeding the specified pressure, resulting in an increase in oil temperature. If the system pressure is too low, the operating organization will frequently open the relief valve to unload under normal load, causing most of the hydraulic oil to flow back to the tank through the safety valve. This will increase the work power of the hydraulic system and cause the hydraulic system to overflow and heat up.

If the pressure of the pilot relief valve is too low, the steering valve stem of the machine will be blocked, resulting in slow movement and high temperature of hydraulic oil. Therefore, it is necessary to check and adjust the safety valve according to the different load requirements of the excavator. Pressure to reach the set value.