The oil seal quality lip geometry is unqualified, the tightening spring is too loose, etc., causing air tightness test leaks. After the KCB gear oil pump is installed in the main machine, the oil seal is easily broken down and the oil is broken. The oil seal should be replaced and the material, geometry and dimensions checked. KCB gear oil pump oil seal is broken down and the cause of oil is one. The quality of parts manufacturing is poor.
1. The quality of the oil seal The geometry of the lip is unqualified, the tightening spring is too loose, etc., causing the airtightness test to leak. After the KCB gear pump is installed in the main engine, the oil seal is easily broken down and the oil is broken. The oil seal should be replaced and the material, geometry and dimensions checked.
2, KCB gear oil pump processing, assembly quality Due to the KCB gear oil pump processing, assembly quality problems, resulting in the gear shaft rotation center and the front cover stop is not the same, Bo Taibang caused oil seal partial wear. The symmetry and displacement of the front cover bearing hole to the locating pin hole, the concentricity of the front cover stop to the skeleton oil seal hole, and the coaxiality of the skeleton oil seal hole to the bearing hole (through hole) should be checked.
3, the sealing ring material and processing quality due to the sealing ring material and processing quality problems, resulting in cracks and scratches in the sealing ring, resulting in a secondary seal is not strict or even failure, a large amount of pressure oil into the skeleton oil seal (here is the low pressure channel) It was too late to return oil, which caused the oil seal to be broken down and oiled. The sealing ring material and processing quality should be checked.
4. The internal spline of the transmission spline shaft is connected with the external spline of the KCB gear pump. And installed on the loader together, if the coaxiality of the spline shaft spline processing is too poor, the rotation will be different, causing the KCB gear pump shaft to swing, affecting the oil seal and sealing, resulting in oil seal string oil. The concentricity of the inner and outer splines of the spline shaft should be checked and controlled.
Second, the installation quality of KCB gear oil pump and main engine does not meet the requirements
1. The installation of KCB gear oil pump and mainframe does not meet the requirements.
After the KCB gear oil pump is installed on the main machine, the coaxiality error of the installation is required to be less than 0.05mm.
If the end face of the spline shaft of the transmission is over-jumped to the center of rotation of the spline shaft, the KCB gear pump will be subjected to radial force under high-speed rotation, thereby causing the oil seal to be broken down and oiled; especially the bushing type CBZb pump, the radial bearing of the gear bearing will damage the radial compensation of the bushing, and its damage is much greater than the fixed clearance CBGKCB gear pump.
2. The installation clearance between components is not required. The front and rear pump cover of the KCB gear pump and the pump body stop function. Therefore, the fit clearance cannot be too large; the external spline of the KCB gear oil pump belongs to the transmission device, and the clearance is not suitable. Too small, otherwise it will form interference.
3. The asbestos pad between the end face of the front cover of the KCB gear pump and the end face of the transmission is too thick. During the installation process, the clamping forces of the four fixing bolts are inconsistent, causing the deflection of the pump and affecting the seal of the oil seal. Asbestos pad and sealant are used between the end faces of the assembly. Although the seal is relatively reliable, it brings a lot of inconvenience to the maintenance. The asbestos pad after the glue can only be used once. Whether changing the KCB gear pump or variable speed pump, replace the asbestos pad every time. It is recommended to use an oil-resistant rubber mat of 0.6 to 0.8 mm thick, which not only ensures the seal, but also makes the pump less biased. It can also be used repeatedly and can reduce vibration and noise.
4. The spline rolling key causes the oil seal string oil. The length of the effective contact between the KCB gear oil pump shaft spline and the shifting output shaft spline is short, and the torque transmitted by the KCB gear oil pump is certain. When the KCB gear oil pump is working, the spline is subjected to a large torque to cause crushing wear or even a rolling key, thereby generating a high temperature, so that the skeleton oil seal lip is burned, aged, and then broken down and oiled. Therefore, the main engine should check the strength of the KCB gear pump shaft spline when selecting the KCB gear oil pump, and ensure that there is enough effective combined length.
Third, the impact of hydraulic system cleanliness Hydraulic system consists of fuel tanks, KCB gear oil pumps, pipelines, control valves and hydraulic cylinders and other important components. When the hydraulic system is working, the hydraulic system is contaminated due to the internal oil passages of various control valves being cast and formed, and the sand adhered to the inside due to the action of the pressure oil and other factors. At the same time, the fuel tank and pipeline welding slag, the internal flashing of the hydraulic cylinder, and burrs are also factors that cause the hydraulic system to be contaminated. After the hydraulic system is contaminated, the friction between the friction pair of the KCB gear pump is intensified, and the sealing effect is effective, thus causing the KCB gear oil pump oil seal to be broken down and the oil is broken. Therefore, it is necessary to carefully carry out valve body cleaning, fuel tank and hydraulic accessories processing, and hydraulic cylinder cleaning to ensure the cleanliness of the hydraulic system.
Fourth, the impact of hydraulic oil
1. The cleanliness of the hydraulic oil is poor, and the gap between the pinion shaft of the large-gear shaft and the inner hole of the seal ring is small. When the contaminated particles enter, the inner hole of the seal ring will wear, scratch or rotate with the shaft, resulting in secondary seal pressure oil. Enter the low pressure zone (the skeleton oil seal), causing the oil seal to be broken down. Filter the hydraulic oil with poor cleanliness or replace the new anti-wear hydraulic oil.
2. The viscosity of the hydraulic oil decreases, the viscosity of the degraded hydraulic oil decreases, and the oil becomes thinner after the deterioration. In the high pressure state of the KCB gear pump, the leakage through the secondary sealing gap increases; the pressure in the low pressure zone rises due to the lack of oil return. High and breakdown of the oil seal leads to string oil. It is recommended to test the oil quality regularly and replace the anti-wear hydraulic oil (L-HM46～68GB11119-98).
Http://news.chinawj.com.cn Editor: (Hardware Business Network Information Center) http://news.chinawj.com.cn
