Common fault of gear oil pump in hydraulic system and its elimination method

Common faults of gear pump in the hydraulic system and troubleshooting methods are mainly divided into the following points: 1, the pump does not pump oil if found in the main engine debugging gear pump does not come to oil, first check the rotation direction of the gear pump is correct. Gear pump has left, right rotation, if the rotation direction is wrong, its internal gear meshing volume difference formed by the pressure oil will make the oil seal was washed out and oil leakage. Secondly, check whether the oil filter at the end of the oil inlet of gear pump is blocked, it will cause difficulty in oil absorption or less than oil absorption, and produce the phenomenon that the oil absorption hose is sucked flat.

2, the oil seal is rushed out (1) gear pump rotation is wrong. When the rotation direction of the pump is not correct, the high-pressure oil will directly pass to the oil seal. As the general low-pressure skeleton oil seal can only bear the pressure of 0.5mpa at most, the oil seal will be rushed out. (2) Gear pump bearing to bear axial force. Axial force is often associated with the gear pump shaft extension end and shaft sleeve with too tight, that is, the pump will be installed with a hammer or hard pull through the installation of screws and the pump shaft by a backward axial force, when the pump shaft rotation, this backward axial force will force the pump wear intensified. Because the gear pump internal is by the gear end face and shaft sleeve end face fit seal, when its axial seal end face wear is serious, the pump internal axial seal will produce a certain gap, resulting in high and low pressure oil cavity communication and oil seal out. This situation appears more in the dump truck industry, mainly due to the size of the main shaft sleeve is not standard. (3) gear pump bear too much radial force. If the gear pump installation of coaxiality is not good, will make the pump by the radial force beyond the bearing limit of oil seal, will cause oil seal oil leakage. At the same time, will also cause damage to the pump internal floating bearing.

3, the establishment of pressure or pressure is not enough to appear this phenomenon is mostly related to the cleanliness of hydraulic oil, such as the incorrect selection of oil or use of oil in the cleanliness of less than the standard requirements, will accelerate the pump internal wear, resulting in the leakage. Therefore, mineral hydraulic oil containing additives should be selected, which can prevent oil oxidation and bubbles. Standard for the oil viscosity (16 ~ 80) x 10-6 m2 / s filtration precision is: input oil less than 60 ц m. By observing the fault of the gear pump shaft sleeve and side plate found that if all the oil cleanliness difference will lead to friction pair surface obvious trenches, and the normal wear of the gear pump sealing surface will only produce uniform surface marks.

4, the flow is not up to the standard (1) oil inlet filter element is too dirty, insufficient oil absorption. (2) The pump installation height is higher than the pump self-priming height. (3) Gear pump suction pipe is too fine to cause oil absorption resistance. Generally, the maximum oil absorption velocity is 0.5 ~ 1.5m/s. (4) Leakage of oil suction nozzle joint causes insufficient oil absorption of oil pump. By observing whether there are bubbles in the tank, you can determine whether the system is leaking air.

5, gear pump burst: aluminum alloy gear pump pressure resistance capacity is 38 ~ 45MPa, in the absence of manufacturing defects in the premise, gear pump burst is certainly caused by the moment of high pressure. (1) There is a foreign body in the oil outlet pipe blocked, resulting in an infinite rise in pressure. (2) The pressure adjustment of the relief valve is too high, or the opening and closing characteristics of the relief valve is poor, the response lag, so that the gear pump can not be protected. (3) the system such as the use of multi-way directional control valve, some multi-way valve may be negative opening, so will encounter due to dead point boost and suppress bad gear pump.

6, heating (1) system overload, mainly in the pressure or speed is too high. (2) Poor oil cleanliness, aggravated internal wear, resulting in a decline in volume efficiency, oil leakage and throttling from the internal clearance, resulting in heat generation. (3) The discharge pipe is too fine and the oil flow rate is too high, generally the oil flow rate is 3 ~ 8m/s.

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