The best method for cleaning bearings

The best method for cleaning bearings

Most of the newly purchased bearings are coated with grease. These oils are mainly used to prevent bearing rust and do not provide lubrication, therefore, they must be thoroughly cleaned before installation and use. The cleaning method is: bearings sealed with rust proof oil can be cleaned with gasoline or kerosene. For bearings that use thick oil and rust proof grease such as industrial Vaseline for rust prevention, they can be first heated and dissolved with No. 10 engine oil or transformer oil for cleaning (the oil temperature should not exceed 100 ℃), and then immersed in oil. After the rust proof grease dissolves and cools down, clean it with gasoline or kerosene. Bearings that use vapor phase agents, rust proof water, and other water-soluble rust proof materials for rust prevention can be cleaned with soap based cleaning agents such as 664, Pingjia, 6503, 6501, etc.

When cleaning with gasoline or kerosene, hold the inner ring of the bearing with one hand and slowly rotate the outer ring with the other hand until the oil stains on the rolling elements, raceways, and retainers of the bearing are completely washed away, and then clean the surface of the outer ring of the bearing. When cleaning, attention should also be paid to slowly rotating and shaking back and forth at the beginning, and excessive force should not be used to rotate, otherwise the bearing raceway and rolling elements are easily damaged by attached dirt. When the amount of bearing cleaning is large, in order to save gasoline and kerosene and ensure cleaning quality, it can be carried out in two steps: coarse and fine cleaning.

For bearings that are difficult to disassemble, they can be rinsed with tear oil. Spray hot oil with a temperature range of 90 ° C to 100 ° C to dissolve the old oil. Use an iron hook or a small spoon to remove the old oil from the bearing, then rinse the remaining old oil and engine oil inside the bearing with kerosene, and finally rinse it with gasoline.

The cleaning quality of bearings relies on tactile inspection. After cleaning the bearing, carefully observe that there will always be some remaining oil in the inner and outer raceway, rolling elements, and gaps in the cage. When inspecting, you can first scrape off the remaining oil with a clean feeler gauge, apply it to your thumb, and slowly rub it back and forth with your index finger. If there is a rustling sound between your fingers, it indicates that the bearing has not been cleaned thoroughly and should be washed again. Finally, hold the bearing in your hand, pinch the inner ring, and rotate the outer ring horizontally (large bearings can be placed on an assembly table, with the inner ring cushioned and the outer ring suspended, pressing the inner ring tightly, and rotating the outer ring). It is qualified if the rotation is flexible, unobstructed, and free of jumping.

After adding lubricant to the cleaned bearings, they should be placed on the assembly table with a clean cloth or paper pad underneath and covered with plastic cloth for assembly. They are not allowed to be placed on the ground or in boxes. When moving bearings, it is not allowed to hold them directly by hand. Canvas gloves or a clean cloth should be worn to wrap the bearings before taking them. Otherwise, due to sweat and moisture on the hands, the bearings may develop fingerprint rust upon contact.

For bearings with dust covers or sealing rings on both sides, as well as bearings coated with rust proof and lubricating grease, do not clean them before installation because lubricating grease has been injected during manufacturing. For example, 51708ZHS (formerly code 688808) bearings are used for the clutch of Gongnong-12, Hongwei-12 hand tractors, and Dongfanghong 20 tractors.

Cleaning of shaft and bearing housing holes and other parts

First, clean with gasoline or kerosene, wipe clean with a dry cloth, and then apply a small amount of oil to facilitate installation. After cleaning these parts, attention should be paid to thoroughly removing any sand on the castings; When there are burrs and sharp corners on the components that match the bearing, they must be removed to prevent residual sand and metal debris from falling into the bearing during installation and affecting the assembly quality. matters needing attention

For bearings with separable inner and outer rings, do not confuse the outer rings to avoid affecting the contact quality. For self-aligning ball and self-aligning roller bearings, it is not allowed to arbitrarily remove and mix the rolling elements in the bearing to avoid installation position confusion affecting accuracy.