Most of the rotating shafts (parts) on the automobile are supported by bearings. Once the bearings fail, the automobile will generate noise or the related parts will work abnormally, which will affect the normal use or endanger the driving safety. Therefore, on the basis of understanding the structural characteristics and working environment of vehicle bearings, it is necessary to use them correctly and maintain them carefully. There are many rolling bearings installed on automobiles, which are widely distributed and have many problems. They are the focus of maintenance.
Before assembly, check the appearance of the bearing to determine whether it can continue to be used. The method is: ① Rotate the cleaned bearing, check the rolling element and the inner and outer race raceways, and replace any pitting or ablation. ② Rotate the bearing for several turns, listen to whether the sound is uniform and free of abnormal noise, and check whether the bearing frame is deformed and whether the rolling element is excessively worn. Any bearing with loose frame (rolling element falling off the bearing frame) or obvious abnormal noise shall be replaced. ③ Check whether the inner and outer race raceways of the bearing have obvious indentations (especially tapered bearings), and replace them if any, because the existence of indentations will affect the adjustment of their preload. ④ Check whether the fit between the bearing and the shaft or bearing hole meets the requirements. If the fit of the bearing is loose, replace it with a new one.
Lubrication of bearing The lubrication performance of bearing directly affects its service life, and then affects the working performance and maintenance cycle of the assembly. ① For bearings lubricated with lubricating oil, no special measures are required because they are generally well lubricated, but the quality and quantity of lubricating oil shall be guaranteed. ② When lubricating with grease, the grease shall be selected according to the requirements of the manual. For example, the amount of lubricating grease for wheel hub bearing shall be kept at 2/3 of the bearing clearance volume, and the hub between two bearing bearings shall not be filled with lubricating grease; For high speed rotating bearings such as generators and water pumps, the grease should be filled to 1/3 of their clearance volume. ③ Scientifically determine the replacement cycle. The best time to replace the lubricating grease is when it is about to harden and deteriorate. It is neither too late nor too early, which puts forward a specific requirement for the driver: master the vehicle use status. Due to the different working environment of each bearing, the difficulty of grease filling varies. Therefore, the grease should be replaced timely according to the mileage of the vehicle and the working environment of the bearing. The replacement cycle of lubricating grease for water pump bearing and transmission shaft spider bearing should be relatively short. ④ For the pressure bearing lubricated by the mixture of lubricating oil and grease, due to the difficulty in filling the lubricating oil, it is necessary to heat and soak it for several hours before taking it out for use. For oil filled pressure bearing, it is unnecessary to add lubricating grease during use.
The adjustment of bearings In order to keep the bearings in good working condition and extend their service life, the adjustment of coaxiality and preload during assembly is essential.
The purpose of coaxiality adjustment is to make the bearing and matching shaft have a good working position. For the shaft positioned by the positioning device, check whether the snap ring is good and reliable, whether the shaft shoulder is flat, and whether there are impurities on the surface before assembly. During the tightening of the locking bolt of the bearing cover, the bearing shall be rotated continuously to make it self correct during rotation, and then the bolt shall be locked according to the specified torque.
Adjusting the bearing preload is to force a certain axial displacement between the inner and outer rings of the bearing to improve the bearing support stiffness. The bearing with proper preload shall rotate flexibly, and there is no obvious clearance feeling when it is pushed, pulled or pried axially. The adjustment methods include: ① thread adjustment method. That is, the bearing preload, such as hub bearing and steering gear bearing, is adjusted by screwing in and out the adjusting nut. This method is simple, but after adjustment, the adjusting nut (nail) should be locked to prevent the adjusted preload from changing due to its looseness. ② Shim adjustment method. That is, the appropriate preload is obtained by increasing or decreasing the thrust washers of the inner and outer rings of the bearing. During adjustment, the increase and decrease of shims shall not affect the overall assembly quality of the assembly. For example, improper increase or decrease of the adjusting shim of the driving bevel gear bearing of the reducer will damage the engagement mark of the bevel gear and affect the working performance of the reducer.
Precautions for bearing replacement ① Select the bearing with the same model as the original bearing for replacement. ② The bearing of the loose frame shall be replaced as a whole, not only the bearing frame or rolling element. ③ Imported bearings should preferably be of the same model as those of the original vehicle. If domestic bearings are used instead, the technical standards, models and requirements in relevant manuals or instructions should be consulted to ensure the correctness of their selection.
More about UNIM Bearing Unit:
UNIM Bearing Units include 20 Series bearings, 30 Series bearings, 40 Series bearings.
The ball bearing unit consists of an insert bearing installed in the housing. The insert bearing is a deep groove ball bearing with a spherical (convex) outer surface and an extended inner ring, which includes a mechanism for locking the unit to the shaft. The housing has corresponding spherical but concave holes.
Sealed spherical bearings and bearing unit are characterized by having sealing shields mounted on the external edge of both sides of the bearing. These protect against particles entering the bearing and act as a barrier against the lubricant leaving the bearing.
2022-11-21
