(1) Improper oil selection for variable vane pump
The brand, quality and viscosity grade of the oil do not meet the requirements, or different brands of hydraulic oil are mixed, causing the viscosity index of the hydraulic oil to be too low or too high. If the oil viscosity is too high, the power loss will increase and the oil temperature will rise; if the viscosity is too low, the leakage will increase and the oil temperature will rise.
Preventive measures: The oil selected should be determined according to the manufacturer’s recommended grade and the working environment and temperature factors where the machine is located. For some machines with special requirements, special hydraulic oil should be used; when the maintenance of hydraulic components and systems is inconvenient, anti-wear hydraulic oil with good performance should be used.
(2) Serious pollution
The environment at the construction site is harsh. As the working time of the machine increases, impurities and dirt are easily mixed into the oil. The contaminated hydraulic oil enters the matching gaps of pumps, motors and valves, which will scratch and destroy the precision and roughness of the matching surfaces. , causing leakage to increase and oil temperature to rise.
Preventive measures: Generally change the oil after more than 1,000 hours of cumulative operation. When changing the oil, be careful not only to drain out the old oil in the fuel tank, but also to replace the old oil in the entire system pipeline and working circuit; when refueling, it is best to use a filter with a mesh size of 120 or more, and add enough oil according to regulations to ensure that The oil has sufficient circulating cooling conditions. In the event of a sudden failure caused by hydraulic oil contamination, the hydraulic system oil must be filtered or replaced. For example, a yzt14g road roller experienced problems with the hydraulic oil temperature being too high and insufficient vibration force; inspection found that the hydraulic oil was milky white, had deteriorated, and had a reduced viscosity. After the hydraulic oil was replaced, the operation of the roller returned to normal.
Post time: Jan-10-2024