Analysis of loader gear pump oil seal oiling (with photos)

"Gear pump channeling oil", that is, the hydraulic oil will penetrate the skeleton oil seal and overflow. This phenomenon is ubiquitous, the main engine factory reflects strongly, gear pump oil disruption seriously affect the normal operation of the loader and gear pump reliability and environmental pollution. In order to facilitate the solution of the problem, the reason and control method of the gear pump oil seal shifting oil fault are analyzed. 1 parts manufacturing quality (1) oil seal quality. Such as oil seal lip geometry failure, tighten the spring is too loose, resulting in tightness test leaks, gear pump installed in the host after the channeling oil. At this point should replace the oil seal and test the material and geometry (domestic oil seal with foreign advanced oil seal compared to the larger the quality gap). (2) gear pump processing, assembly. If the gear pump processing, assembly problems, resulting in rotation of the gear shaft center and the front cover is not the center of the heart, will cause oil partial wear. At this time should check the front cover bearing hole symmetry of the pin hole, the displacement, the skeleton of the coaxial bearing bearing hole. (3) sealing ring material and processing quality. If there is a problem, resulting in cracks and scratches the seal ring, resulting in the second lax seal or failure, the pressure oil into the framework of the seal (low pressure channel), and thus seal the oil. At this point should check the seal ring material and processing quality. (4) variable speed pump processing quality. The feedback information from the OEMs and gear pump assembly together with the gear pump oil seal oil transfer more serious problems, so the variable speed pump processing quality has a greater impact on the channeling oil. Variable speed pump mounted on the gearbox output shaft, gear pump and through the variable speed pump port positioning and installed on the gearbox output shaft, if the variable speed pump end face of the gear center of rotation beating tolerance (verticality), will be The gear shaft rotation center and seal center do not coincide and affect the seal. Variable speed pump processing, trial production process, should check the rotation center of the coaxiality of the stop and stop the end face of the beating. Figure 1 CBG gear pump section (5) CBG gear pump seal between the oil seal and the seal back to the oil return channel is not smooth, causing the pressure rise here, and thus breakdown skeleton oil seal. Through the improvement here, the pump oiling phenomenon has been significantly improved. The structure of the form shown in Figure 1. 2 gear pump and the host installation quality (1) gear pump and the host installation requirements coaxial less than 0.05. Usually working pump installed in the variable speed pump, variable speed pump installed in the gearbox. If the transmission or variable speed pump end surface of the spline shaft center of the beat beating error, the formation of cumulative error, resulting in high speed rotation of the gear pump to withstand radial forces, resulting in oil seal oiling. (2) Whether the installation gap between the components is reasonable; gear pump outside the stop and the variable speed pump stop and gear pump spline and gear spline shaft spline, the gap between the two is reasonable, are gear pump The channeling oil have an impact. Because the internal and external stop belongs to the positioning part, with the gap should not be too large; internal and external splines are part of the transmission, with the gap should not be too small to eliminate interference. (3) gear pump oil and its spline key is also related. As the gear pump shaft extension spline and gearbox output shaft Huacao effective contact length is short, while the gear pump torque transmission work is large, the spline to withstand large torque squeeze wear and tear or rolling key, resulting in huge heat , Resulting in skeleton oil seal rubber lip burn, aging, resulting in channeling oil. It is recommended that OEMs use gear pumps to check the spline strength of the gear pump shaft to ensure sufficient effective contact length. 3, the impact of hydraulic oil (1) ultra-poor hydraulic oil cleanliness, pollution particles, a variety of hydraulic control valves and pipe sticky sand, welding slag, etc. are also one of the causes of pollution. Because the shaft diameter of the gear shaft and the clearance of the inner hole of the seal ring are small, larger solid particles in the oil enter between them, resulting in the abrasion of the inner hole of the seal ring, scratching or rotation with the shaft, causing the pressure oil of the secondary seal to enter the low pressure zone Skeleton seal), resulting in seal breakdown, this time should be filtered or replaced with new anti-wear hydraulic oil. (2) After the viscosity of hydraulic oil is decreased and deteriorated, the oil gets thinner. Under the condition of high pressure of the gear pump, the leakage through the secondary seal gap increases. Since it is too late to return the oil, the pressure in the low pressure zone increases and the oil seal breaks down. It is recommended to regularly test oil, use anti-wear hydraulic oil. (3) When the host large load working time is too long and the fuel tank surface is low, the oil temperature can be increased to 100 ℃, resulting in thinning oil, aging oil seal lips, resulting in channeling oil; should be checked regularly tank fluid Surface height, to avoid the oil temperature is too high.