The reason why the oil seal is extruded in the process of gear pump rotation is that the pressure cannot be established or the pressure is not enough
(1)
KCB gear pump under excessive radial force. If the coaxiality of gear pump installation is not good, the radial force of the pump will exceed the bearing limit of the oil seal, which will cause oil seal leakage. The axial force is often associated with the gear pump shaft extension and coupling sleeve is too tight, that is, when the installation of the pump hammer hit or hard pull through the installation screw and the pump shaft is subjected to a backward axial force, when the pump shaft rotates, the axial force will force the back of the pump wear. At the same time, it will also cause damage to the floating bearing inside the pump.
(2) explosion-proof gear pump bearing to axial force.
This phenomenon is mostly related to the cleanliness of hydraulic oil, such as the incorrect selection of oil or the cleanliness of the oil in use can not meet the standard requirements, will accelerate the internal wear of the pump, resulting in the discharge. When the rotation of the pump is not correct, the high pressure oil will directly pass to the oil seal, because the general low pressure skeleton oil seal can only bear the pressure of 0.5mpa at most, so the oil seal will be rushed out.
. This situation appears more in the dump truck industry, mainly due to the size of the host coupling sleeve is not standardized. Therefore, mineral hydraulic oil containing additives should be selected to prevent oxidation and bubble formation of oil. By 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, the surface of the friction pair will produce obvious grooves, and the normal wear of the gear pump sealing surface will only produce uniform surface grooves.
(3) The rotation of insulation gear pump is wrong. The viscosity standard of oil is (16 ~ 80) ×10-6m2/s. The filtering precision is: input oil path is less than 60 (help - aid - aid - aid). Because the internal gear pump is on the gear end face and shaft sleeve end face fitting seal, when the axial seal end face wear is serious, the internal axial seal of the pump will produce a certain gap, resulting in high and low pressure oil chamber communication and the oil seal rushed out.
