Cause Analysis and Solution of High Oil Temperature Failure of Hydraulic System（1）

Cause Analysis and Solution of High Oil Temperature Failure of Hydraulic System（1）

The high oil temperature of the hydraulic system will have a serious impact on the normal operation of the hydraulic system. The high oil temperature may be just the appearance, and there are various root causes behind the failure.

01

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The hazards of high hydraulic oil temperature

①The viscosity of hydraulic oil, volumetric efficiency and hydraulic system work efficiency are all reduced, leakage increases, and even the mechanical equipment cannot work normally

②The parts of the hydraulic system expand due to overheating, which destroys the original normal matching clearance of the relative moving parts, resulting in increased frictional resistance and easy jamming of the hydraulic valve. At the same time, the lubricating oil film becomes thinner and the mechanical wear increases. As a result, pumps, valves, Precision mating surfaces of motors, etc., become invalid or scrapped due to premature wear.

③Accelerate the deterioration of rubber seals, shorten their life, and even lose their sealing performance, making the hydraulic system...

02

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The general causes, consequences and solutions of the increase in oil temperature of the hydraulic system

The hydraulic system has energy loss during work, including pressure loss, volume loss and mechanical loss. These losses are converted into heat energy, which increases the oil temperature of the hydraulic system. The oil temperature of the general hydraulic system should be controlled within the range of (30-60) ℃. 

An increase in oil temperature will cause a series of undesirable consequences:

(1) Decrease the viscosity of the oil, increase leakage, reduce volumetric efficiency, and even affect the normal movement of the working mechanism; 

(2) Deteriorate the oil, produce oxide impurities, and block Small holes or gaps in hydraulic components make them unable to work normally; 

(3) Cause the gap between relative moving parts with different thermal expansion coefficients to become smaller, or even get stuck and unable to move; 

(4) Cause thermal deformation of machine tools or machinery , Destroy the original accuracy.

Measures to ensure the normal working temperature of the hydraulic system: 

 1. When the setting value of the pressure control valve is high, the working pressure should be lowered to reduce energy loss;                                                                                                                                                     2. When the volume loss caused by the leakage of the hydraulic pump and its connections causes heat , All connections should be tightened to strengthen the seal; 

 3. When the volume of the fuel tank is small and the heat dissipation conditions are poor, the volume of the fuel tank should be appropriately increased, and a cooler should be installed if necessary;

 4. Because the oil viscosity is too high, the internal friction will increase When heating, hydraulic oil with low viscosity should be selected; 

 5. When the oil pipe is too slender and bent, which increases the resistance loss of the oil along the way and the oil temperature rises, the pipe diameter should be increased, and the pipe should be shortened to make The oil is unobstructed; 

 6. When the temperature of the oil rises due to the high temperature of the surrounding environment, heat insulation materials and reflectors should be used to isolate the system from the outside; 

 7. The high-pressure oil returns to the tank from the overflow valve unnecessarily for a long time When the oil temperature rises, the circuit design should be improved, and variable pumps or unloading measures should be adopted.