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Excavator hydraulic system analysis of the reasons for high temperature

Excavator Hydraulic oil temperature is too high, can produce thermal deformation of mechanical and hydraulic components in thermal expansion coefficients of different moving parts because the gap is smaller and stuck, causing action failure, affecting the accuracy of the hydraulic drive system, resulting in the quality of work becomes part poor. Viscosity of oil is also reduced, leakage increases, the pump efficiency and volumetric efficiency of the system will be significantly reduced. Since the viscosity of the oil is reduced, oil film is thin and so moving the slide valve member, the frictional resistance increases, resulting in increased wear. High temperature deformation of rubber seals will accelerate the aging failure, reduce the sealing performance and service life, resulting in leakage.

In addition, the temperature rise also accelerated oxidative deterioration of oil and bituminous substances precipitation, reduce the life of hydraulic oil. Precipitates plugging holes and crevices damping valve opening, causing the pressure valve inoperable death card, stretch and bend metal piping code, and even rupture. Temperature also reduces air separation oil pressure, oil dissolved air to escape, cavitation, resulting in reduced performance hydraulic system.

Excavator Hydraulic oil temperature is too high for two main reasons:

1.a tank volume is too small, not enough cooling area; oil cooling system is not installed, or despite a cooling device but its capacity is too small.

2. Press the fast forward speed selection quantitative pump oil pump capacity system, most of the excess will flow at high pressure and heat from the relief valve overflow back at work.

3. The system of unloading circuit malfunction or because unloading circuit is not set, the pump does not stop working when unloading pump all traffic at high pressure overflow, overflow losses and heat generation, resulting in warming.

4. The system piping too small for too long, too much bending, large local pressure loss and pressure loss along the way.

5. A lack of precision components and poor quality of assembly, mechanical friction losses relative motion between.

6. mating parts with the gap is too small, or cause wear and tear after the gap is too big, inside and outside large leak, resulting in a large volume loss. A volumetric pump efficiency is reduced, the rapid temperature rise.

7. The hydraulic system pressure adjustment is much higher than the actual need. Sometimes because of tight seal, or due to damage seals leak and had to increase the pressure increases to work.

8. Climate and operating environment of high temperature, resulting in temperature rise. 9. Select the oil’s viscosity properly, large viscosity viscous resistance, viscosity increases too small leak, two situations can cause fever temperature.

Preventive measures:

1. Depending on the load requirements, always check and adjust the pressure relief valve to make it just right.

2. A reasonable choice of hydraulic oil, not to mention the oil viscosity, under the conditions permit, as far as possible in order to reduce the viscosity of low viscosity that friction losses.

3. Improved lubrication of moving parts to reduce friction loss, help to reduce the workload and reduce fever.

4. To improve assembly quality hydraulic components and hydraulic systems and their accuracy, and strictly control the mating member with the gap and improving lubrication conditions. Using low coefficient of friction and improved sealing structure sealing material, to minimize starting force of the hydraulic cylinder, in order to reduce heat generated by the mechanical friction loss.

5. The additional cooling capacity or strengthened where necessary.

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