Bearing overhaul and judgment
In order to determine whether the dismounted bearing can be used, it is necessary to check the bearing after washing.
Check the condition of the rolling road surface, rolling surface, counterface, the wear of the cage, the increase in bearing clearance, and the damage and abnormality of the unrelated dimensional accuracy degradation.
Detached bearings such as tapered roller bearings can be inspected separately for rolling elements and raceway surfaces of the outer ring.
Bearing cleaning
When dismounting the bearing for maintenance, first record the appearance of the bearing, confirm the residual stock of lubricant, and then wash the bearing after sampling and inspecting the lubricant.
Cleaning agents generally use ordinary gasoline and kerosene.
The cleaning of the dismantled bearings, divided into coarse cleaning and fine cleaning, is placed in the container, and the metal net is placed at the bottom of the net, so that the bearing does not directly contact the swag of the container.
During rough cleaning, if the bearing is rotated with swag, the rolling surface of the bearing will be damaged, and attention should be paid to it. In the coarse cleaning oil, use a brush to remove degreasing grease and stickers, and after roughly cleaning, transfer to fine washing.
Fine cleaning is the rotation of the bearing in the cleaning oil while carefully cleaning. In addition, the cleaning oil should be kept clean frequently. (Pictured below)
Bearings can no longer be used if they have the following defects:
(1) There are cracks or gaps in any one of the inner ring, outer ring, rolling elements, and cage;
(2) There is a break in any one of the ferrules and rolling elements;
(3) The raceway surface, flange, and rolling elements have significant jams;
(4) The cage wears significantly, or the willow nails are significantly relaxed;
(5) There is rust and injury on the raceway surface and rolling body;
(6) The raceway surface and rolling elements have serious indentation and markings;
(7) There is obvious creep on the outer warp surface of the inner ring and the outer warp surface of the outer ring;
(8) The discoloration caused by heat is obvious;
(9) The bearings sealed with grease, the damage of the sealing ring or dust cover is obvious.
Precautions for bearing use
Rolling bearings are precision components, and no matter how high-performance bearings are used, if used improperly, they will not get the expected high performance. The precautions for the use of bearings are as follows:
First, keep the bearing and its surrounding environment clean
Even tiny dust invisible to the naked eye enters the bearing, which increases bearing wear, vibration and noise. Bearings and their peripheral accessories should be kept clean, especially dust and dirt, tools and the environment must also be kept clean.
Second, the use of installation precautions
Strong stamping is not allowed, direct hammering of bearings with hammers, and pressure transfer through rolling elements is not allowed.
Third, use appropriate and accurate installation tools
Try to use special tools and try to avoid things like cloth and staple fibers.
Fourth, to prevent the corrosion of the bearing
When holding the bearing directly by hand, it is necessary to wash the sweat from the hands thoroughly and apply high-quality mineral oil before operating, especially in the rainy season and summer to pay attention to rust prevention. However, under certain operating conditions, bearings can achieve longer life than conventional calculations, especially at light loads. These special operating conditions are the surface damage that can result when the rolling surface is effectively divided by a lubricant film and contaminants are limited. In fact, under ideal conditions, so-called permanent bearing life is possible.
Common problems and countermeasures in the use of bearings
1. Abnormal load: select the appropriate assembly clearance and preload.
2. Poor assembly: improve the machining accuracy of the shaft and improve the installation method.
3. Insufficient lubricant: Supplement or use a suitable lubricant.
The rotation vibration of the shaft is large:
1. Spalling: fatigue peeling, replacement of bearings.
2. Poor assembly: improve the machining accuracy of the shaft and improve the installation method.
3. Foreign intrusion: clean related parts, use clean grease.
Large discoloration of lubricant leakage:
1. Too much lubricant: less lubricant.
2. Foreign body intrusion: cleaning related parts