When buying bearings, do you doubt that the higher the speed of the bearing, the easier it is to use? The faster the more expensive? Is that true? We will explain the bearing speed and the factors affecting the bearing speed in detail:

For each bearing, it has its own limit speed. The speed of the bearing is mainly limited by the temperature rise caused by friction heating in the bearing. When the speed exceeds a certain limit, the bearing will be unable to continue to rotate due to burns, or even jam the bearing.

Therefore, we are rotating the appropriate bearing type according to the speed of the bearing, so we need to select the requirements of the bearing. In some applications, other factors are more important than the limit speed. Such as low speed, reciprocating swing, etc.

The limit speed of bearing refers to the boundary value of friction heating and continuous rotation without burn. Therefore, the limit speed of bearing depends on the type, size and accuracy of bearing, lubrication method, quality and quantity of lubricant, material and type of cage, load conditions and other factors.

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

The speed range required for the application helps to determine what kind of bearing to use. Most bearing manufacturers' catalogues provide the limit speed value of the product. Practice has proved that it is best to work at 90% lower than the limit speed.

1. Select the bearing category according to the speed

a. The limit speed and rotation accuracy of ball bearing are higher than that of roller bearing, so high speed should be given priority to ball bearing.

b. When the inner diameter is the same, the smaller the outer diameter is, the smaller the rolling element is, and the smaller the centrifugal inertia force added by the rolling element on the foreign raceway is, which is suitable for high-speed work. Therefore, the bearings with smaller outer diameter in the same diameter series should be selected on the expressway. If the bearing with small outer diameter is used and the bearing capacity cannot meet the requirements, the same bearing can be installed or a wide series of bearings can be considered.

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

The allowable speed of solid cage is higher than that of stamping cage, and the allowable speed of bronze solid cage is higher.

Deep groove ball bearing, angular contact bearing, cylindrical bearing, angular contact bearing, cylindrical roller bearing;

Tapered roller bearings can be used in low-speed working situations.

The limit speed of tapered roller bearing is generally about 65% of deep groove ball bearing, 70% of cylindrical roller bearing and 60% of angular contact ball bearing. The limit speed of thrust ball bearing is low, so it can only be used in low-speed occasions.

2. Factors affecting bearing speed

The factors affecting the bearing limit speed include the magnitude of applied load, stress direction, type of lubricant, quantity of lubricant, bearing manufacturing accuracy, bearing tolerance grade and bearing clearance.

In addition, the lubricant may be superior to other properties, but it is not suitable for high-speed rotation.

The factors of bearing limit speed are related to the type, load, accuracy, size, lubrication, clearance, cage and cooling conditions of the bearing. However, the most important factor is the allowable operating temperature or lubricant of the bearing material.