All aspects of the analysis of the hydraulic system temperature is too high

The temperature rise of hydraulic oil is too high, which can cause mechanical thermal deformation. The moving parts with different thermal expansion coefficient in hydraulic components are stuck because of their smaller matching clearance, causing action failure and affecting the transmission accuracy of hydraulic system, resulting in poor working quality of components. But also the viscosity of oil is reduced, leakage increases, pump volume efficiency and the efficiency of the whole system will be significantly reduced. As the viscosity of the oil decreases, the oil film of the sliding valve and other moving parts becomes thinner, and the friction resistance increases, leading to increased wear. High temperature will make the rubber seal deformation, accelerate aging failure, reduce sealing performance and service life, resulting in leakage.

In addition, the temperature increase also accelerates the oil oxidation deterioration, and asphalt material precipitation, reduce the service life of hydraulic oil. Precipitates plug damping holes and gap valve ports, resulting in pressure valve stuck and unable to operate, metal pipeline elongation and bending, or even rupture. The temperature rise also reduces the air separation pressure of oil, and the dissolved air in oil escapes, resulting in cavitation, which reduces the working performance of the hydraulic system.

The main reasons for the high temperature rise of hydraulic oil are as follows: 1. The tank volume is too small and the heat dissipation area is not enough; No oil cooling device is installed or there is a cooling device but its capacity is too small. 2. The quantitative pump oil supply system with fast forward speed to select the oil pump capacity will have most of the excess flow from the relief valve under high pressure and heat up at work. 3. When the unloading loop in the system is faulty or no unloading loop is set, the oil pump cannot be unloaded when it stops working. All the flow of the pump overflows under high pressure, resulting in overflow loss and heating, resulting in temperature rise. 4. The system pipes are too thin and too long, and too much bending, resulting in large local pressure loss and pressure loss along the pipeline. 5. The precision of components is not enough and the assembly quality is poor, and the mechanical friction loss between relative movements is large. 6. The fit clearance of the parts is too small, or the gap is too large after wear, and the internal and external leakage is large, resulting in large volume loss. If the volumetric efficiency of the pump is reduced, the temperature rises quickly. 7. The working pressure of the hydraulic system is adjusted much higher than the actual need. Sometimes it is because the seal is too tight, or because the seal is damaged, the leakage increases and the pressure has to be adjusted to work. 8. High climate and operating environment temperature result in high oil temperature. 9. Choose the improper viscosity of oil, the viscosity is large and the viscosity resistance is large, and the viscosity is too small to increase the leakage. Both cases can cause the heating and temperature rise.

Preventive measures: 1. According to different load requirements, often check and adjust the pressure of the overflow valve, so that it is just right. 2. Choose hydraulic oil reasonably, especially the viscosity of oil. If conditions permit, try to use a lower viscosity to reduce the loss of viscosity friction. 3. Improve the lubrication conditions of moving parts to reduce friction loss, which is conducive to reducing work load and reducing heat. 4. Improve the assembly quality and accuracy of hydraulic components and hydraulic system, strictly control the fitting clearance of fitting parts and improve lubrication conditions. Adopting sealing material with small friction coefficient and improving sealing structure, reduce the hydraulic cylinder's starting force as much as possible, so as to reduce the heat generated by mechanical friction loss. 5. Add or strengthen cooling capacity if necessary.