Rolling bearings are often made of quenched steel and are usually mounted on steel shafts with a press fit (interference fit). However, in actual working conditions, bearings often operate in environments much higher than room temperature. Temperature changes will cause linear expansion of bearings, shafts, and bearing seats, thereby quietly changing the "tightness of the interference fit" and "the size of the bearing clearance."
Temperature difference and linear expansion
Temperature differential expansion is an "invisible but critical" influencing factor in bearing operating conditions. Especially in high-temperature equipment (such as aerospace engines, metallurgical machinery), more attention should be paid to:
When selecting materials, try to match the expansion coefficients of the bearing, shaft, and bearing seat (to reduce drastic changes in interference);
During the design stage, use the above formula to estimate the temperature difference expansion and adjust the initial values of interference fit and clearance in advance;
If the temperature difference of the equipment fluctuates greatly, you can choose bearings with "compensable clearance" (such as spherical roller bearings with adapter sleeves).
Source: Bearings and Basic Parts Committee