When a ball screw vibrates or squeals at high speed, most engineers blame screw accuracy or assembly. But the real culprit is often the support bearing clearance — an easily overlooked detail that causes both micro-vibration and high-frequency noise.
Too Tight = Vibration, Too Loose = Noise
Tight clearance causes thermal expansion to lock the bearing, amplifying micro-eccentricity into visible vibration. Loose clearance lets rolling elements impact the raceway, generating wideband shock pulses that produce sharp squealing.
Why Fixed Clearance Fails
Standard clearance values from catalogs are measured at room temperature. Once the machine warms up, effective clearance changes. A single fixed value cannot cover all speed and load conditions.
The Right Approach
Calculate the effective clearance at thermal steady state based on actual operating speed and temperature range, then work backward to determine the cold assembly value. Match preload accordingly.
Bottom line: Support bearing clearance must be selected dynamically based on speed, temperature, and preload — not picked from a fixed table.
(Source: Production line statistics and industry selection handbooks)