1, gear oil pump internal parts wear will cause internal leakage. The leakage area between the floating sleeve and the end face of the gear is large, which is the main part of internal leakage. This part of the leakage accounted for 50 to 70 percent of the total internal leakage. The volume efficiency of the gear pump decreases with the wear leakage, and the output power of the gear pump is much lower than the input power. Its loss is all converted into heat energy, so it will cause gear oil pump overheating. If the joint plane is pressed, the floating bushing will be worn due to a small amount of movement during operation, resulting in slow or unable to lift the farm tools. Such floating bushing must be replaced or repaired.
2, gear oil pump shell wear is mainly floating sleeve hole wear (gear shaft and sleeve normal clearance is 0.09~0.175mm, the maximum shall not exceed 0.20mm). Gear work by the action of pressure oil, gear tip close to the gear oil pump housing, wear pump body part of the low pressure cavity. Another kind of wear is the circular wear of the working surface in the shell. This kind of wear is mainly caused by the unclean oil added, so the oil without impurities must be added.
3, oil seal wear, rubber seal aging unloading piece of rubber oil seal aging deterioration, loss of elasticity, high pressure oil chamber and low pressure oil chamber lost sealing isolation, will produce high pressure oil chamber to low pressure oil chamber, known as "leakage", it reduces the working pressure and flow rate of gear oil pump. CB46 gear pump its normal working pressure is 100~110kg/ cm2, the normal oil flow is 46L/min, the standard unloading piece rubber oil seal is 57×43. Since the tight oil seal is PG25 * 42 * 10 skeleton oil seal, it damaged or years of failure, the air from the oil seal and the gaps between the spindle axis neck or from the inlet flange and > > > gear pump gear pump gear pump gear oil pump shell junction inhaled > gear oil pump, gear pump by the return hose into the tank, to produce a large number of bubbles in the tank. It will cause the decrease of oil in the oil tank and the increase of oil in the bottom tank of the engine oil, so that the lifting of agricultural tools is slow or cannot be lifted. The oil seal must be replaced to eliminate this problem.
4, gear oil pump oil supply is insufficient or no oil pressure phenomenon: the working device lifting slowly, shaking or can not lift; There are bubbles in the oil tank or oil pipe; When lifting, the hydraulic system makes a "chirp, chirp" sound; When the tractor is just started, the working device can be lifted. After the oil temperature rises for a period of time, the lifting is slow or cannot be lifted. Light load can lift, heavy load can not lift the telescopic stage. Fault causes :(1) the oil level of the hydraulic tank is too low; (2) hydraulic oil is not used seasonally; (3) The inlet pipe is seriously blocked by dirt; (4) The driving gear oil seal of gear oil pump is damaged, and air enters the hydraulic system; (5) Gear oil pump inlet and outlet joint or bend joint "O" shaped seal ring damage, bend joint fastening bolts or inlet and outlet pipe nut is not tightened, air into the hydraulic system; (6) Gear oil pump > gear oil pump > gear oil pump > gear oil pump leakage, aging seal ring; (7) the end face of the gear oil pump or the end face of the main and driven gear sleeve is worn or scratched, and the roughness of the end face of the two sleeve is out of tolerance; (8) Internal leakage caused by assembly errors of internal parts of gear oil pump; (9) "left rotation" installed "right rotation", resulting in broken skeleton oil seal; (10) Hydraulic oil is too dirty.
