Construction machinery has different requirements for the quality of hydraulic oil

Construction machinery has different requirements for the quality of hydraulic oil


1、 Quality requirements for hydraulic oil

The quality of hydraulic oil will greatly affect the working reliability and service life of hydraulic system. Generally, the quality requirements for hydraulic oil are as follows:

a. Suitable viscosity and good viscosity temperature performance
b. Good rust resistance and anti-oxidation safety
c. Good foam resistance
d. Good demulsibility
e. Good extreme pressure and wear resistance

In addition to the above basic quality requirements, there are special requirements for some hydraulic oils with special performance requirements. For example, the low-temperature hydraulic oil shall have good low-temperature performance; Fire resistant hydraulic oil requires a hydraulic system with good fire resistance.

2、 Performance and evaluation index of hydraulic oil:

a. Good fluid state ~ the fluidity of hydraulic oil directly affects the effect of energy transfer.
b. Good incompressibility and foam resistance ~ the volume of liquid is not easy to change under the action of external force, but its compressibility will be affected when the liquid is mixed with air. Maintaining the incompressibility of hydraulic oil is very important for the hydraulic oil as the working medium to reliably transmit energy and ensure the sensitive action of the control mechanism
c. Good extreme pressure antiwear ~ the development trend of hydraulic pump is miniaturization and high pressure, which requires hydraulic oil to have good extreme pressure antiwear. The so-called garbage pressure anti-wear property refers to the ability of oil products to prevent wear caused by relatively direct metal contact by maintaining the oil film between the surfaces of moving parts.
d. Good oxidation stability ~ the colloid and sediment generated after the oxidation of hydraulic oil will affect the normal operation of hydraulic components, especially some control mechanisms. In addition, the generated acid oxide will also cause the hydraulic components to be corroded. Therefore, the hydraulic oil is required to have good oxidation stability.
e. Good sealing adaptability ~ during the working process of the hydraulic transmission device, there are often problems of internal leakage and external leakage, which will cause hydraulic oil leakage and pollute the environment; Internal leakage leads to unstable operation of the transmission device and deterioration of working conditions. Therefore, the hydraulic oil is required to adapt to the sealing materials used to minimize internal and external leakage.
f. Good filterability ~ hydraulic equipment requires more stringent hydraulic components and higher accuracy, which increases the sensitivity of the device to impurities. As long as there are small impurity particles, the equipment will be worn and out of order; On the other hand, after the hydraulic oil is polluted by water in use, the water will promote the decomposition of additives in the oil, and the decomposition products will be deposited on the filter surface, which may increase the clogging trend of the filter. Therefore, hydraulic oil is required to have good filterability.