Temperature limits and thermal expansion
The permissible operating temperature for polymer ball bearings is limited by the type of polymer. Diagram 1 provides a summary of the operating temperatures for polymer materials. When temperatures outside the permissible range or below 0 °C (30 °F) are expected, contact the SKF application engineering service.
In combination with the operating temperature, thermal expansion is also important. The coefficient of thermal expansion (diagram 2) enables designers to predict the effects that temperature has on bearing internal clearance. The coefficient of thermal expansion for a polymer can be up to 10 times greater than for steel. Even the coefficient of thermal expansion for different polymers can vary considerably. Therefore, thermal expansion can have a significant influence on bearing internal clearance and should be considered when selecting shaft and housing fits (→ Shaft and housing fits) and when selecting the bearing materials.