Gear pump is through a pair of parameters and structure of the same involute gear rolling mutual engagement, the tank of low pressure oil to work can be an important part of high pressure oil. Is the engine of mechanical energy into hydraulic power unit. Dongfanghong -75 Tractor and Dongfanghong-60, 70T bulldozer using CB46 gear pump. Dongfanghong -802 / 802K tractors and Dongfanghong -802KT bulldozers using CBN-E450 or CBTI-E550 gear pump, the pump flow, reliability and good. In the course of its use prone to the following problems. 1, gear pump internal parts wear pump internal parts wear will cause internal leakage. Among them, the leakage area between the floating bushing and the gear end face is large, which is the main part of the internal leakage. This part of leakage accounted for 50% of the total internal leakage of about 70%. The wear and tear of the lost circulation gear pump volumetric efficiency decreased, pump output power is much lower than the input power. The loss of all the heat into the heat, it will cause the pump overheating. If the combination of flat compression, due to work floating sleeve will be a small amount of exercise caused by wear and tear, resulting in slow or can not enhance the farm tools, such a floating sleeve must be replaced or repaired. 2, gear pump housing wear mainly floating sleeve hole wear (gear shaft and sleeve of the normal gap is 0.09 ~ 0.175mm, the maximum shall not exceed 0.20mm). Gear work by the role of pressure oil, the gear tip close to the pump housing, wear low pressure chamber part of the pump. Another kind of wear is the circumferential wear of the working surface in the shell. This wear is mainly caused by the net oil added, so the oil without impurities must be added. 3, gear pump oil seal wear, rubber sealing aging unloading sheet rubber seal aging deterioration, loss of elasticity, the high pressure oil chamber and the low pressure oil chamber lost seal isolation, will produce high pressure oil pressure to the low pressure oil chamber, said As "leakage", it reduces the working pressure and flow of the pump. CB46 gear pump its normal working pressure of 100 ~ 110kg / cm2, the normal oil volume is 46L / min, the standard unloading sheet rubber seal is 57 × 43. Since the tight seal is PG25 × 42 × 10 of the skeleton oil seal, its damage or long-term failure, the air from the seal and the journal of the gap between the shaft or from the inlet plate and the oil pump housing junction is sucked into the pump, The return pipe into the tank, a large number of bubbles in the tank. Will cause the tank of oil to reduce the engine oil tank in the phenomenon of increased oil, so that agricultural tools to enhance slow or can not be improved. You must replace the oil seal to eliminate this fault. 4, the oil pump insufficient or no oil pressure phenomenon: work equipment to enhance slow, when lifting trembling or can not be improved; tank or tubing bubbles; enhance the hydraulic system issued a "jack, jack" sound; tractor just started work The device can be improved, working for a period of time after the oil temperature rises, the slow increase or can not be promoted; Light load can be improved, heavy load can not be extended telescopic stage. Fault reason: (1) (3) Inlet pipe is seriously clogged with dirt; (4) Oil pump gear seal is damaged and air enters into the hydraulic system; (5) O-shaped seal of oil inlet and outlet or elbow joint Circle damage, bend the bolt fastening bolts or into and out of the tubing nut is not tight, the air into the hydraulic system; (6) pump leakage, seal aging; (7) the end face of the pump or driven gear shaft sleeve wear Or scratches, the end surface of the two bushings unevenness; (8) the pump internal parts assembly error caused by internal leakage; (9) "left-handed" mounted "right-handed" pump, causing damage to the skeleton seal; dirty. Gear pump troubleshooting: (1) according to the season to add or replace the required grade oil to the provisions of the oil surface. Take out the foreign matter in the tubing and tighten the bolt or nut at the joint. (2) Replace the aged or damaged skeleton oil seal or "O" shaped sealing rubber ring. (3) Replace the worn gear oil pump or oil pump sleeve for slight wear Flatten the face on the flatbed. Its unevenness allow error of 0.03mm; the end of the upper sleeve lower than the plane of the pump body (normal value less than 2.5 ~ 2.6mm), such as ultra-poor should be in the next shaft sleeve plus 0.1 ~ 0.2mm copper to compensate, when installed Should be set in the rear sleeve on the load; (4) unloading film and the seal ring must be installed in the oil chamber, the two bushing in order to maintain balance. (5) The guide wire elastic force should be able to reverse the rotation of the upper and lower sleeves toward the driven gear at a slight angle so that both the main and driven gear shafts (6) unloading trough on the sleeve must be installed in the low-pressure chamber side to eliminate the gear meshing harmful dead volume; (7) pressed into the tight oil seal, should be at The surface coated with a layer of lubricating oil, but also pay attention to the oil-resistant edge toward the front cover, can not be installed anti-; (8) "right-handed" pump can not be installed in the " Before installing the pump cover, pour a small amount of oil into the pump housing and rotate the gear with hand; (10) Before installing the oil pump cover without tightening the bolts, check the clearance between the pump cover and the pump body, 0.6mm, if the gap is too small, should be replaced by large seals and pressure relief parts. After the hydraulic pump is installed, it should be flexible and free from jamming.