Why is preload important in bearings?

Preload in bearings is crucial primarily because it eliminates any internal play, ensuring that the components are in proper alignment during operation. When there is no play, the contact between the rolling elements and the raceways is optimized, which helps in reducing wear and extending the life of the bearing. Proper alignment is critical for maintaining accurate rotor or shaft positioning, which is especially important in precision machinery.

A well-preloaded bearing allows for better load distribution across the rolling elements, which can enhance load-carrying capacity and performance. It also minimizes the chances of vibration or oscillation that could lead to premature failure of the bearing or misalignment of the overall assembly. This careful management of spacing and alignment is essential for the long-term reliability of rotative systems.