For each bearing, there is its own limit speed, bearing speed is mainly limited by the temperature rise caused by friction heating inside the bearing. When the speed exceeds a certain limit, the bearing will not continue to rotate because of burns, etc., or even make the bearing stuck.

Therefore, we rotate the appropriate bearing type according to the speed of the bearing, so we need to understand the requirements of the speed selection of the bearing. In some applications, other factors are more important than the limit speed. Such as: low speed, reciprocating swing and so on.

The limit speed of bearings refers to the limit value that does not produce friction heating that causes burns and can be continuously rotated. Therefore, the ultimate speed of the bearing depends on the type, size and accuracy of the bearing, as well as the lubrication mode, the quality and quantity of lubricant, the material and type of the cage, load conditions and other factors.

The limit speed given by the bearing manufacturer generally refers to the highest speed that can be achieved under agreed conditions: for example, the bearing tolerance is level 0; Bearing clearance is 0 group; Bearing load is 10% of rated load; Lubrication cooling condition is normal; Radial bearing only bears radial load, thrust bearing only bears axial load; The outer ring temperature does not exceed 100℃, etc.

The speed range required in the service situation helps to decide what type of bearing to use. Most bearing manufacturers’ product catalogs provide the limit speed value of their products. Practice has proved that it is better to work under the state of 90% limit speed.

The selection of rotating speed to bearing category

A. Ball bearings have higher limit speed and rotation accuracy than roller bearings, so ball bearings should be preferentially selected at high speed.

B. Under the condition of the same inner diameter, the smaller the outer diameter, the smaller the rolling body, and the smaller the centrifugal inertia force of the rolling body on the foreign raceway during operation, so it is suitable for working at a higher speed. Therefore, at high speed, it is advisable to choose bearings with smaller outer diameters in the same diameter series. If a bearing with a smaller diameter and the bearing capacity is not up to the requirements, the same bearing can be installed again, or consider using a wide series of bearings.

C. The material and structure of the cage have a great influence on the bearing speed.

Solid cages allow higher rotational speeds than ram cages and bronze solid cages allow higher rotational speeds.

General high speed of work, should choose deep groove ball bearings, angular contact bearings, cylindrical roller bearings;

Tapered roller bearings can be used in low speed working occasions.

The ultimate speed of tapered roller bearings is generally about 65% of deep groove ball bearings, 70% of cylindrical roller bearings and 60% of angular contact ball bearings. The ultimate speed of thrust ball bearings is low, and can only be used for low speed occasions.

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