Bearing clearance cause of grease discoloration

After have a vibration motors apart, bearing grease into a silver ( The original is milky white) Caused, what's the problem? Bearing grease color change is normal, grease into what is normal? What level is normal. Some bearing grease is also becomes angry, milky-white brown, and the part of the color change is rolling around the body, what reason is this? If become silver is due to fit tight, small clearance, the friction caused by the large, but there is the same bearing outer ring run laps of the phenomenon. Is this why? The discoloration of grease in the bearing is some, if not put in bearing, would become angry. This is because: first, grease oxidation problems. Grease is placed ( Or run) A period of time, will and oxygen, there are a lot of contact, at the same time, metals ( The bearing itself) ACTS as a catalyst role in the oxidation reaction. So, in the calculation of bearing grease in added time interval of time, also want to consider the problem of oxidation. Now there are a lot of grease has antioxidant additive. This is not equal to just won't be the oxidation. Second, the bearing running itself, temperature ( The bearing itself, or the environment) Will change, this leads to the grease base oil constantly in and out of the thickener, every time base oil back at the same time, not necessarily completely back. So for a long time, between the performance of the grease will change, will not meet lubrication and so need to lubrication. Base oil shortage of grease, the color may change. Also, if the temperature anomaly, the performance of the oil change is big, so there will be change color. If the temperature is very high, carbide. The color will be darker. Third, the operation process of bearing, grease inside with the impurities. This impurity is probably the bearing itself peeling, it is possible that the outside world. May be solid, liquid, these will affect the nature of the grease. Tight, in addition you said small clearance, lead to oil change color. This reasoning should be like this: cooperate tightly, work ( The remaining) Small clearance, bearing load area increase, fever, cause fat degeneration, lead to oil color changes. Run laps and you said, the first possible bearing chamber with you have any question, second, the internal clearance is too small, high friction, lead to run laps. Behind a possibility, not by the tight fit. F be the worse. Also, what you said is judged by the color of the grease situation is normal. This judgment is very difficult and different internal grease additives is different, different running conditions, to adapt to the different temperature range, there can be no unified standard. Even the same kind of grease, may also be due to the appearance of different batches, the formula is slightly different. Please do not use this color change as the basis, unreliable.