Before disassembling the bearing, make preparations for bearing maintenance, stop the vehicle stably and set up the axle to ensure the safety of maintenance operation.
Necessity of Selecting lubricant for Bearing Maintenance
(1) Remove the decorative cover and dust cover of the bearing head;
(2) Remove the tire nut and tire, and be careful not to damage the thread of the tire bolt. If it is a disc brake, remove the brake and then use it to remove the lock ring or lock pin.Necessity of Selecting lubricant for Bearing Maintenance
(3) Remove the bearing with special tools;Necessity of Selecting lubricant for Bearing Maintenance
(4) Scrape off the old grease in the bearing, journal and bearing cavity, clean the bearing and journal with cleaning agent and wipe dry with cloth, and then wipe the bearing cavity with cloth.
(5) Check the bearing and bearing race. If cracks, fatigue peeling and loose bearing rollers are found, replace the bearing. If pitting is found on the bearing race, the bearing should also be replaced.
(6) Check the fit between the inner diameter of the bearing and the journal. The fit clearance shall not be greater than 0.1omm. When measuring the journal, it shall be measured at the upper and lower parts of the vertical ground (where there is a large wear part). If the fit clearance exceeds the specified service limit, replace the bearing to restore the normal fit clearance. It is not allowed to reduce the clearance by burring and pitting on the journal.
(7) After all parts meet the requirements, apply grease to the inner bearing and put it into the bearing.
(8) When applying grease to the inner cavity of the bearing, pay attention to squeeze the grease into the bearing until the grease comes out from the other side of the bearing. Apply a thin layer of grease in the bearing cavity and the shaft head cover to prevent rust. Pay attention not to apply too much grease in the bearing cavity, otherwise it will affect heat dissipation and braking.Necessity of Selecting lubricant for Bearing Maintenance
(9) Install the bearing and outer bearing back on the journal, screw the shaft head adjusting nut by hand, and then tighten the adjusting nut with the shaft head wrench according to the specified torque.
After tightening the nut, turn the bearing left and right for several turns to see the installation of the bearing; On the other hand, rotate to make the bearing and race fit correctly. At this time, the bearing tightness is appropriate, and the wheel rotates freely without axial clearance.Necessity of Selecting lubricant for Bearing Maintenance
(10) Install the locking plate, fixing nut, tire, dust cover, decorative cover and other parts in turn.
(11) After the bearing is adjusted, drive for a certain mileage (about 1okm) and stop for inspection to wipe the temperature of the bearing. If the heating is caused by too tight adjustment of the bearing, it should be readjusted and the bearing tightness should be properly relaxed.Necessity of Selecting lubricant for Bearing Maintenance
The necessity of bearing lubrication is also confirmed by the test and practice. The 42724 bearing is tested at the speed of 14.3t and equivalent to 140km / h. When 5g grease is added, the bearing can run for 7h, while when there is no grease, it can only run for 10min, and the service life difference is 42 times;
According to the statistics of the vehicle department, due to poor sealing and mixing with water and sand dust, the bearing lubrication is damaged, resulting in the replacement proportion of different types of bearings as high as 30-60%.
The above situation fully shows that normal lubrication conditions are an important prerequisite for giving full play to the internal life of the bearing.
Taken together, rolling bearing grease will play the following essential roles:Necessity of Selecting lubricant for Bearing Maintenance
1. Reduce friction. The lubricating grease forms an oil film between the rolling element and the inner and outer rings, and between the cage and the outer ring of the rolling element. This liquid lubricating film can reduce and prevent metal contact, which will greatly reduce the wear between the friction parts of the bearing and reduce the heat generated by their mutual friction.
2. Abrasion resistance. Elastic deformation will occur between the rolling faces of the bearing under base load; When there is eccentric load in the bearing, there will be relative slip between the rolling working surfaces. The liquid lubrication film can greatly reduce the scratch caused by the above phenomena, so as to prolong the fatigue life of the bearing.
3. Heat dissipation. Grease can dissipate the heat generated by rolling working face through rolling, flow and conduction.
4. Shock absorption and noise reduction. The lubricating oil film can absorb part of the energy and partially convert the concentrated load into distributed load, which plays the role of shock absorption and noise reduction.
5. Seal. The grease also prevents dust and moisture from invading the rolling working surface of the bearing. The bearing grease applied in some oil seals is completely for filtering.
6. Rust and corrosion prevention. Rolling bearing grease is generally a good anti rust and anti-corrosion agent, which can prevent bearing corrosion.