The Dalan Hydraulic System reminds you to solve the problem of the internal gear pump. First, you need to understand the working principle of the internal gear pump.
The Dalan Hydraulic System reminds you to solve the problem of the internal gear pump. First, you need to understand the working principle of the internal gear pump.
At present, the internal gear pump commonly used has a tooth profile curve of an involute gear pump and a cycloidal gear pump (also known as a rotor pump). Their working principle and main features are basically the same as external gear pumps.
When the pinion gear is the driving gear, when the rotation is in the direction shown in the figure, the gear exits the meshing volume and absorbs the oil, and the meshing volume is reduced to pressurize the oil. In the involute toothed internal gear pump chamber, a crescent-shaped baffle is placed between the pinion and the internal gear to separate the oil suction chamber from the oil pressure chamber.
The pinion gear of the cycloidal internal gear pump differs from the internal gear by one tooth, so that no spacer is required. The internal gear pump has compact structure, small size, light weight, stable operation, small flow pulsation, low noise, and high volumetric efficiency when working at high speed. Since the gears are turned the same, the relative sliding speed between the gears is small, the wear is small, and the service life is long. However, the tooth shape is complicated, the processing is difficult, and the price is higher than that of the external gear pump.
At present, there are many kinds of cycloidal pumps in China, and the maximum working pressure is ≤2.5MPa. The BB type internal meshing cycloidal gear pump is a positive displacement internal gear pump. The internal gear (ie, the outer rotor) is a circular arc tooth shape, and the outer gear (ie, the inner rotor) is a new type of gear pump with a short outer cycloid. Because of its simple structure, low noise, smooth oil delivery and high self-priming performance, the pump is widely used in low pressure hydraulic systems. It is widely used in machine tools, gearboxes, compressors, transmission machinery, lifting and handling machinery and other hydraulic systems with mechanical pressure less than 2.5MPa. It can be used as cooling pump for power pump or lubrication pump. This pump is suitable for conveying various oils. class.
The failure of the internal gear pump is as follows:
1. High pressure fluctuations
1 The pump body and the front and rear covers are not well processed, the eccentricity error is large, or the clearance between the outer rotor and the pump body is too large. In this case, the eccentricity should be checked and the eccentricity error should be within ±0.02 mm. The clearance between the outer rotor and the pump body should be in the range of 0.04 to 0.06 mm.
2 The internal and external rotors (cycloidal gears) have poor tooth profile accuracy. The inner and outer cycloidal gears are mostly pressed by powder metallurgy molds, and the mold and other reasons may affect the tooth profile accuracy of the cycloid gear wheel. Users can correct it. Serious damage must be replaced.
3 The inner and outer rotors have large radial and end faces. Correct the inner and outer rotors to achieve the technical requirements.
4 The inner and outer rotors have a large tooth backlash. Replace the inner and outer rotors to ensure that the backlash is within 0.07mm.
5 The air is mixed into the pump. Remove air from the system and take measures to prevent air from entering the pump from the pump suction line.
2, can not suck oil or insufficient oil absorption
1 The inner rotor does not rotate. Check if the oil pump drive system worm, worm gear or gear, inner rotor fastening screw or locating pin are loose, and if the worm gear meshes with the spindle worm.
2 The rotation direction of the inner rotor does not match the prime mover, which causes the inlet and outlet ports to be reversed. Confirm that the machine is rotating in the working direction.
3 The oil outlet pipe is blocked. Check if the oil pipe of the oil outlet is blocked or damaged.
4 The inlet filter is clogged. Clean the filter to remove blockages.
5 The inner and outer rotors are severely worn, resulting in the formation of a closed cavity. Replace the inner and outer rotors.
6 The end face of the oil inlet pipe is in contact with the bottom surface of the oil groove, resulting in poor oil intake. Ensure that the end face of the oil inlet pipe has a certain distance from the bottom surface of the oil groove, so that the oil inlet is smooth.
7 Inhale air from the suction port of the pump. Make sure that the connecting parts of the pump suction passage are tightly connected and that there is no air leakage, and the suction port is immersed in a certain depth of oil.
8 The oil level in the fuel tank is too low. Ensure that the oil level in the fuel tank reaches a certain height.
3, the pressure is not high
1 Inhale air from the suction port of the pump. Make sure that the connecting parts of the pump suction passage are tightly connected and that there is no air leakage, and the suction port is immersed in a certain depth of oil.
2 The inner rotor speed is too low. Check the spindle to inner rotor power transmission connection for loose or slipping.
3 The suction port is partially blocked. Check if the suction port area is effective enough.
4 The worm gear, worm or gear meshing state is not good, and the time difference is good, which causes the inner rotor speed to be high and low. Check if the oil pump drive system worm, worm gear or gear, inner rotor fastening screw or locating pin are loose, and if the worm gear meshes with the spindle worm.
4, the cycloid rotor oil pump is too noisy
1 The oil level is too low to take in air, or the filter is partially blocked, resulting in insufficient oil absorption. Fill or clean the filter to make the oil absorption smooth.
2 parts are seriously worn. Replace with a new pump or a worn part.
3 The position of the pump power transmission meshing point has changed. When adjusting, pay attention to the original meshing point of the machine drive gear.
5, cycloidal rotor oil pump extravasation oil
1 The pump body fastening screw or the joint is loose. Tighten the screws or connectors.
2 The seal is damaged. Replace the seal.
3 The oil outlet flange is poorly sealed. Remove dirt, burrs, and reinstall.
4 The pump body, pump cover, etc. are deformed or damaged. Repair or replace the cycloidal rotor pump.
----- Editor-in-Chief: Dalan Oil Pump Motor 02-Procurement Consultant
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