Since some important parts of the turbocharger are high temperature resistant materials, for example, the turbine is a ceramic alloy, all the replacement parts are used during the inspection. Which parts need to be replaced and which ones do not need to be replaced are evaluated in terms of ablation, wear, deformation, and geometrical error. Due to the geometrical errors of different turbochargers, the assembly clearances are different, so the inspection and replacement judgments mentioned here are based on visual appearance inspection.
1. Supercharger floating bearing
Turbocharger bearings typically use either floating or rolling bearings. High-speed turbochargers have always used highly reliable floating bearings. There is a certain gap between the floating bearing and the rotor journal and the intermediate housing. During turbocharger operation, the rotor shaft and the floating bearing are all floating in the lubricating oil without mechanical friction between them. The lubrication between the rotor shaft of the supercharger and the bearing is pressure-lubricated. The lubricating oil comes from the main oil passage of the engine and is filtered by the fine filter to enter the intermediate casing of the supercharger. If the oil is dirty or deteriorated during use, the floating bearing is not easy to form an oil film. The bearing is easily scratched in the semi-dry friction, and even the overheating causes the bearing to deform or bluish. If it is scratched, deformed or bluish after disassembly, it must be replaced. If the floating bearing in the middle of the turbocharger is found to be carbon deposited, the inlet and outlet of the turbocharger oil should be unblocked; the oil filter should be replaced and the standard oil should be added.
2. Thrust bearing plate
When the turbocharger is working, if the oil supply is sufficient, the thrust bearing plate generally does not wear out, but if the oil is dirty or deteriorated, it is easy to block the oil inlet hole, form a semi-dry friction, cause wear, and deformation, disassembly rear view Replace the situation.
3. Overhaul of air compressor housing
If there is light scratch on the inlet of the air compressor casing pressure surface, the small burrs and nicks on the compressor casing can be smoothed with fine sand cloth; if the compressor casing pressure surface is deeply scratched, it cannot be used continuously. . If the compressor casing is cracked or deformed, it should be scrapped.
4. Turbine shell overhaul
The function of the turbine casing is to collect the air flowing out of the diffuser and direct it to the compressor outlet. The air continues to decelerate and pressurize in the volute, completing the process of transitioning from kinetic energy to pressure energy. Visually inspect the turbine casing for contact with the impeller; inspect the mounting flange and the crack at the V-belt. Check whether there is crack at the inlet end of the turbine casing, whether there is deformation or burning in the inlet and outlet, etc. If there is crack, deformation, burning, serious corrosion, etc., it should be replaced with new ones. Under normal circumstances, turbines and bearing seals should be replaced after the farmland operation or transportation operation mileage is 50,000 to 60,000 km.
5. Inspection of bearing shell
Check the bearing shell for cracks at the oil inlet and return joints; measure the inner diameter of the bearing shell; measure the length of the bearing shell at four equidistant positions from the air compressor casing outlet to the turbine casing outlet; if the measurement indicates that the bearing shell has Distortion, the bearing shell should be scrapped.