Why is bearing clearance necessary?

Bearing clearance is essential primarily to accommodate thermal expansion and contraction that occurs in a bearing assembly during operation. When a machine operates, components like the inner and outer rings of a bearing, as well as the rolling elements, experience changes in temperature. As these components heat up, they expand; conversely, they contract when cooled.

If proper clearance is not maintained, the expanded parts could interfere with each other, leading to excessive friction, potential seizure of the bearing, increased wear, and ultimately, premature failure. Therefore, providing adequate clearance ensures that the bearing can function smoothly while still allowing for these natural thermal changes without risking interference between parts.

While lubrication flow is important for bearing performance and longevity, and rotation speed can be influenced by various factors including bearing design and conditions, the primary reason for the necessary clearance revolves around managing thermal expansion and contraction effectively.