1. Bearing cleaning
Most of the newly purchased bearings are coated with grease. These greases are mainly used to prevent the bearings from rusting and do not act as a lubricant. Therefore, they must be thoroughly cleaned before they can be installed. The cleaning method is: the bearings sealed with anti-rust oil can be cleaned with gasoline or kerosene. For heavy-duty oils and anti-rust greases such as industrial Vaseline rust-proof bearings, first use 10 or 8 oil or transformer oil to heat and dissolve (oil temperature should not exceed 100 °C), and immerse the bearings in oil. After the rust-proof oil is melted and taken out, it is cooled, and then washed with gasoline or kerosene. Bearings that are rust-proof with gas phase, rust-proof water and other water-soluble rust-preventing materials can be cleaned with other soap-based cleaning agents such as 664, flattening, 6503, 6501.
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 on the rolling elements, raceways and cage of the bearing is completely washed away, then clean the outer ring of the bearing. surface. When cleaning, it should also be noted that it should be rotated slowly at the beginning, reciprocating and shaking, and should not be excessively rotated. Otherwise, the raceway and rolling elements of the bearing are easily damaged by the attached dirt. When the number of
bearing cleaning is large, in order to save gasoline, kerosene and ensure the cleaning quality, it can be divided into two steps: coarse and fine cleaning.
For inconveniently disassembled bearings, rinse with hot tears. That is, the hot oil is sprayed at a temperature of 90°-100°C to dissolve the old oil, and the old oil in the bearing is dug with an iron hook or a small spoon, and then the residual oil and oil in the bearing are washed away with kerosene, and finally Rinse it with petrol.
The quality of the bearing is checked by hand. After the bearings have been cleaned, observe carefully that there will always be some remaining oil in the inner and outer ring raceways, on the rolling elements and in the gaps in the cage. When testing, first scrape off with the remaining oil of the clean feeler, apply it on the thumb, and slowly slap it back and forth with your index finger. If there is a rustling sound between the fingers, the bearing is not cleaned and should be washed again. Finally, take the bearing on the hand, pinch the inner ring, and push the outer ring to rotate horizontally (large bearings can be placed on the assembly table, the inner ring pad, the outer ring is suspended, the inner circle is pressed, the outer ring is rotated), to rotate Flexible, unblocked, and no bounce is acceptable.
For the cleaned bearings, after adding the lubricant, it should be placed on the assembly table. The bottom pad should be covered with a net cloth or a paper pad, and covered with a plastic cloth for assembly. It is not allowed to be placed on the floor or the box. When moving the bearing, it is not allowed to take it directly by hand. Wear canvas gloves or use a clean cloth to wrap the bearing and then take it. Otherwise, because of the sweat and moisture on the hand, the bearing will easily produce fingerprint rust after contact.
Bearings with dust caps or seals on both sides, and bearings coated with rust-proof and lubricated greases are greased at the time of manufacture, so do not clean them before installation. For example, workers and peasants - type 12, Red Wei - 12 type hand drag and Dongfang red 20 tractor clutch with 51708ZHS (original code 688808) bearing.
2. Cleaning of shaft and housing housing hole and other parts
Wash with gasoline or kerosene first, wipe with a dry cloth, and then apply a small amount of oil to facilitate installation. After cleaning these parts, it should be noted that all types of sand on the castings should be completely removed; if there are burrs on the parts that are matched with the bearings, they must be removed to prevent residual sand and metal debris from falling into the bearing during installation. Assembly quality.
1. Notes
For bearings that can be separated from the inner and outer rings, do not interchange the outer rings to avoid affecting the contact quality. For the self-aligning ball and spherical roller bearing, the rolling elements in the bearing must not be arbitrarily removed and mixed, so as to avoid the disorder of the installation position and affect the accuracy.
When installing the bearing, in order to facilitate the inspection of the bearing code, it is not wrong, the typing surface of the bearing ring should be placed and installed outward.
2. Heating of bearing and housing housing bore
For medium and large
bearings with large interference, in order to facilitate the installation, pre-heating must be installed; for the tightly fitting light metal bearing housing hole (such as aluminum bearing housing), the hardness is very low, to prevent the bearing outer ring from being pressed. When the surface of the housing hole of the bearing housing is scratched and pulled, it should be heated and installed. The heating method generally involves placing the bearing or the separate type bearing ring into a fuel tank containing clean engine oil, so that the oil floods the bearing and uniformly heats. When the temperature reaches 80-90 ° C, remove it and wipe it clean. The fuel tank can be made of 2-3 mm thick iron plate, a porous iron plate is placed 50-70 mm from the bottom of the box, and the bearing is placed on a porous iron plate for heating. Its purpose is to prevent deposits of impurities in the oil from entering the bearing.
However, for bearings with dust caps or seals on both sides, since the lubricant has been added in the manufacturing process, it cannot be heated in the early stage of installation.
