(1) Oil quality. If the oil has poor foam resistance and is easy to vaporize and form foam, it is easy to cause cavitation.
(2) The oil level is too high or too low. If the oil level is too high, the oil is mechanically stirred and the gas is easy to dissolve in the oil; if the oil level is too low, the working pump is easy to absorb air, resulting in insufficient circulating oil flow, which increases the air or water in the oil to form bubbles Probability. For example, if the transmission oil level is too low, the pressure at the inlet of the variable speed pump will be lower than the vaporization pressure of the oil, and the oil will vaporize or evaporate, and bubbles will be precipitated. These bubbles will burst quickly when they flow to the high pressure area and cause cavitation.
(3) The oil is overheated. If the oil temperature is too high, the oil is easy to vaporize, the water evaporates, the foam and air bubbles increase, and the cavitation phenomenon increases.
(4) The frequency of oil pressure changes is high. The frequency of pressure changes directly affects the formation and rupture speed of air bubbles. The parts with high frequency of pressure changes have a fast cavitation rate. For example, when the construction machinery is operating, the boom and the bucket need to be continuously manipulated, so the position of the distribution valve spool and the oil passage is relatively high due to the high frequency of pressure changes, and the cavitation phenomenon is also serious. There are small pits and scratches.
(5) Poor quality of cooling water. When the cooling water contains corrosive media (such as acid radical ions), it will form a combined effect of corrosion and cavitation, accelerating the rate of cavitation.
(6) Air and moisture invade the oil. The more air and moisture invade the oil system, the wider the range of cavitation. The main channel of air intrusion is the lack of sealing at the pump suction port and pipe joints, which leads to air entering the system. The main channel of moisture intrusion is fear of internal leakage of the cooler.
(7) The cooling system is poorly maintained. The radiator pressure cap and thermostat that have a greater impact on cylinder liner cavitation. A good radiator pressure cap can keep the pressure of the coolant higher than the vapor pressure, thereby reducing the occurrence of cavitation. The thermostat keeps the coolant in a proper temperature range, which can reduce the energy when the bubble bursts. Therefore, if the temperature and pressure loss caused by poor maintenance, the cavitation rate will be accelerated.
(8) Conditions of use. The rough working process of construction machinery, especially diesel engines, has a large explosion pressure, which causes a corresponding increase in the lateral percussion force, which causes an increase in cavitation.