Several common problems in the correct installation of linear bearings
Bearings should be cleaned before installation. When installing, use special tools to press the SKF bearing straight and evenly, do not hit it with a hand hammer, especially prohibit direct hitting on the linear bearing. When the fit between the bearing race and the seat hole is loose, the seat hole should be repaired or the bearing should be replaced, and the method of pitting or padding copper on the mating surface of the bearing should not be forced to use. When disassembling the bearing, use a suitable puller to pull the bearing out, and do not hit the bearing with a chisel or hand hammer.
There are two types of lubricants commonly used in rolling bearings: lubricating oil and grease. When the peripheral speed of the shaft is less than 4-5m/s, or the part of the car that cannot be lubricated with lubricating oil, it is lubricated with grease. The advantage of grease lubrication is that the sealing structure is simple, the grease is not easy to lose, and it is not greatly affected by temperature, and it can be used for a long time after adding grease once.
Two issues should be paid attention to when using lubricating grease. One is to choose a suitable brand of lubricating grease according to the requirements of the car manual. For example, it is not suitable to use nano-based grease for automobile water pump bearings because of its poor water resistance. The second is to add an appropriate amount of grease to the linear bearing. Generally, it is advisable to only fill 1/2-1/3 of the bearing cavity. Too much grease is not only useless, but also increases the running resistance of the SKF bearing, causing it to heat up and generate heat. Special attention should be paid to the bearings of automobile hubs. "Empty hub lubrication" should be advocated, that is, only an appropriate amount of grease can be applied to the bearings. Otherwise, not only waste and poor heat dissipation, but also heat overflow of the grease may affect braking performance.
The advantage of lubricating oil lubrication is that the frictional resistance is small and it can dissipate heat. It is mainly used for bearings with high speed and high working environment temperature. The grade of lubricating oil should be selected according to the requirements of the car manual, and replaced in time according to the car maintenance cycle. After the old oil is released, the mechanism should be cleaned and then new oil should be added. The refueling should be added to the specified marking line, or flush with the fuel filler (Depending on the specific structure and requirements of the car), no more can be added.
Not having regular lubrication will be a problem. In the case of manual maintenance, it is impossible to realize that an automatic lubrication system can be developed to achieve the best lubrication effect. The required grease, tools and effective lubrication techniques will help to significantly reduce downtime. While you can install "free" all types of bearing seals, 36% of premature failures in SKF bearings are still due to incorrect grease technique and misuse. Any linear bearing that is improperly lubricated is an inevitable failure going forward in normal life. Machinery and equipment bearings are often the hardest part of the job.
Bearings are precision components, linear bearings and grease contamination, will not run. In addition, among all SKF bearings that have been sealed with grease for maintenance-free use, at least 14% of the contamination is only significantly caused by the use of bearings in a small percentage of early failures of all bearings. The bearing has excellent manufacturing and design capabilities, and can provide various sealing solutions for severe working conditions.
Cleanliness is very important for rolling bearings. The surface roughness of the rolling surfaces of bearing rings and rolling elements is typically 1/10 μm, and such smooth surfaces are very sensitive to damage from contamination. The lubricating layer between the rotating surfaces is usually 0.2~1 μm. Particle-type impurities larger than the particle size of the lubricant will be over-rolled by the rolling elements and generate local pressure in the bearing steel, which will eventually lead to permanent material fatigue. In addition to this, dust particles in the external environment, up to 10 μm in size, can also cause damage to SKF bearings. Therefore, a clean and dust-free environment is essential for the storage and installation of linear bearings.