The bearing should not be over lubricated

The bearing should not be over lubricated

Grease has good adhesion, wear resistance, temperature resistance, rust resistance and lubricity. It can improve high temperature oxidation resistance, delay aging, dissolve carbon deposition, prevent the agglomeration of metal debris and oil, and improve the wear resistance, pressure resistance and corrosion resistance of machinery.

But after understanding the movement process of grease in the bearing, we will naturally come to a conclusion: the grease in the bearing should not be too much. Too much grease is not only wasteful, but also harmful. The higher the rotational speed of the bearing, the greater the harm. The more grease is filled, the greater the friction torque is. The friction torque of the sealed bearing is greater than that of the open bearing. When the filling amount of grease is equal to 60% of the internal volume of bearing, the friction torque will not increase significantly. This is because most of the grease in the open bearing has been squeezed out, and the grease in the sealed bearing has also been lost. With the increase of the amount of grease filling, the temperature rise of the bearing increases linearly. With the same amount of grease filling, the temperature rise of the sealed bearing is higher than that of the open bearing.

It is generally believed that the filling amount of grease in sealed rolling bearings should not exceed 50% of the internal space at most. The test of experts shows that 20% to 30% is the most suitable for ball bearing. Of course, in order to determine the most appropriate amount of grease filling, sometimes other factors have to be considered. For example, for some open bearings that work in the environment full of dust or very humid or even in contact with steam, more grease can be filled, so as to have a better sealing state and protect the bearings from dust or moisture.