Grease is critical in the use of bearings.If deteriorated grease is used, it will not only fail to function as it should, but also damage the bearing.

1. Oil flow observation

Take two cups, one of which need to be checked out of the lubricating oil, empty on the desktop, the other will be filled with lubricating oil measuring cup for leave desktop 30 to 40 cm tall and lean, let oil flow slowly to the empty cup, to observe the flow situation, when good quality lubricant oil flow should be long and thin, uniform, continuous, if appear oil flow fast and slow, sometimes with large flow, the said lubricating oil has deteriorated.

2. Hand twist method

Twist the lubricating oil between the thumb and the index finger repeatedly grinding, the better lubricating oil hand feel lubricity, less abrasive, no friction, if feel between the fingers of sand and other greater friction sense, it shows that the impurities in the lubricating oil, can not be used again, should replace the new lubricating oil.

3. The illumination method

On a clear day, lift the oil with a screwdriver at a 45-degree Angle to the water level.Compare with the sun, observe the oil droplets, under the light, you can clearly see that the lubricating oil without debris is good, can continue to function, if the debris is too much, should replace the lubricating oil.

4. Oil drop trace method

Take a piece of clean white filter paper and drop a few drops of oil on the filter paper. After the oil leaks, if there is black powder on the surface and there is a feeling of astringence when touched by hand, it indicates that there are many impurities in the oil. The good oil has no powder, and it feels dry, smooth and yellow.

The bearing may be removed from its oil seal packaging shortly before delivery for routine inspection and immersed in washing gasoline or acid-free kerosene containing 3% oil, turn its outer ring and carefully rinse the junction of the cage, roll and racetrack, requiring that any hidden areas of the original oil be thoroughly cleaned.After cleaning, the bearings should be attached to the cleaning oil, dry on the work table lined with clean neutral lining paper, or slowly dry in the far infrared oven.Do not rotate bearing rings, retainers or any rolling elements during the process of drying or drying the self-cleaning oil.

Have dry or drying bearing should, in accordance with the provisions, drip into the lubricating oil and check for immediate delivery, no oil film bearing outer surface protection, in the whole process of inspection shall not directly touch the skin of hands, the operator should wear clean gloves, or hand coated with anti-rust agent, but the rust inhibitor must avoid hand bearing with the rolling surface, otherwise it will result in deviation of measurement results. 

Bearing in the end of the inspection, should be immediately delivered to use or anti-rust inventory treatment, the whole inspection process should be completed quickly, so as not to lead to corrosion for too long.Note that cleaning with pure gasoline without oil will also cause corrosion.Before the bearing is inspected, it must be placed on a sheet of metal in the inspection area, together with the measuring blocks, standard parts and measuring instruments used in the inspection, so that the temperature of these objects can be quickly homogenized and warmed.

Obviously, only by doing the above preparations strictly can we ensure the accuracy of the inspection results and prevent the bearing from rusting during the whole inspection process.