01 Pump does not deliver oil
① It is found that the gear Hydraulic Gear Pump does not output oil during the debugging of the hydraulic system. First, check whether the rotation direction of the gear pump is correct.
②The gear Hydraulic Gear Pump can be divided into left-turn and right-turn. If the direction of rotation is wrong, the pressure oil formed by the volume difference caused by the internal gear meshing will cause the oil seal to be damaged and oil leakage.
③Check whether the oil filter at the oil inlet end of the gear pump is blocked, which may cause difficulty in or inability to absorb oil, and cause the suction hose to be flattened.
02The oil seal is flushed out
① The gear pump rotates in the wrong direction. When the rotation direction of the pump is not correct, the high-pressure oil will directly pass to the oil seal. Generally, the low-pressure skeleton oil seal can only withstand a pressure of 0.5 MPa at most, so the oil seal will be flushed out.
②The gear pump bearing bears the axial force. The axial force produced is often related to the tight fit between the shaft extension end of the gear pump and the coupling sleeve, that is, when the pump is installed, the pump is hit with a hammer or the installation screw is hard pulled to subject the pump shaft to a backward axial force. When the shaft rotates, this backward axial force will force the internal wear of the pump to increase. Because the gear pump is sealed by the end face of the gear and the end face of the shaft sleeve, when the axial seal end face is severely worn, a certain gap will be generated in the axial seal of the pump. As a result, the high and low pressure oil chambers communicate and the oil seal is flushed out. .
③The gear pump bears excessive radial force. If the coaxiality of the gear pump is not good when installed, the radial force on the pump will exceed the bearing limit of the oil seal, which will cause the oil seal to leak. At the same time, it will cause damage to the floating bearings inside the pump.
03 fever
① The hydraulic system is overloaded, which is mainly manifested in the excessive pressure or speed.
②The oil is poor in cleanliness and internal abrasion is aggravated, which reduces the volumetric efficiency, and the oil leaks from the internal gap and generates heat.
③The oil outlet pipe is too thin and the oil flow rate is too high. Generally, the oil flow rate is 3-8m/s.
04The flow is not up to the standard
①The oil inlet filter element is too dirty and insufficient oil absorption.
②The installation height of the pump is higher than the self-priming height of the pump.
③The oil suction pipe of the gear pump is too thin, resulting in high oil suction resistance. Generally, the maximum oil absorption flow rate is 0.5~1.5m/s.
④Air leakage at the suction port joint causes insufficient oil suction by the oil pump. You can judge whether the system is leaking by observing whether there are bubbles in the fuel tank.
05 Cannot be stressed or not stressed enough
① This phenomenon is mostly related to the cleanliness of the hydraulic oil. If the oil is selected incorrectly or the cleanliness of the oil does not meet the standard requirements, it will accelerate the internal wear of the pump and cause leakage.
②Choose mineral hydraulic oil containing additives to prevent oil oxidation and air bubbles.
③By observing the shaft sleeve and side plate of the faulty gear pump, it is found that if the cleanliness of all the oil is poor, it will cause obvious groove marks on the surface of the friction pair, and only uniform marks will be produced on the sealing surface of the normally worn gear pump.
06 Gear pump burst
①The pressure resistance of the gear pump made of aluminum alloy is 38～45MPa. Under the premise of no manufacturing defects, the gear pump burst must be caused by instantaneous high pressure.
②The oil outlet pipeline is blocked by foreign matter, causing the pressure to rise indefinitely.
③The pressure of the safety valve is adjusted too high, or the opening and closing characteristics of the safety valve are poor, and the response is lagging, so that the gear pump cannot be protected.
④ If the system uses a multi-way reversing valve to control the direction, some multi-way valves may have a negative opening, so that the gear pump will be damaged due to the dead point boost.