Jogging Equals Impact: Overlooked Fatigue Life Criteria for Lead Screw Module Selection

Short-stroke high-frequency jogging is one of the harshest working conditions for lead screw modules. Each start and stop creates an impact, and cumulative cycles directly test the fatigue limit of balls and raceways. In selection, equivalent load shall replace static load, and load factors shall be adopted according to impact levels. The key selection points are as follows:

1. Under short-stroke high-frequency jogging conditions, each reciprocation of the lead screw generates tiny stress cycles on the contact surfaces of raceways. Select models whose basic dynamic load rating is much higher than the actual equivalent dynamic load to prevent early pitting and spalling failure.

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3. Strictly control the axial clearance and preload level of the lead screw. High-frequency forward and reverse impacts will cause a "knocking effect" on lead screws with clearance, accelerating damage to balls and nut raceways. Preloaded nuts with zero or minimal clearance are recommended to keep the transmission under constant compression contact.

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7. Verify the impact resistance of bearings at both ends of nuts and lead screws. Instant start-stop produces peak loads far higher than steady-state loads. Neglecting the dynamic and static load ratings of support bearings will lead to premature bearing failure and reverse backlash drift.

8. Adopt lead screws with sufficient diameter and check critical speed and column stability. Under repeated torsion, tension and compression impacts, screws with excessive slenderness ratio are prone to elastic bending or axial buckling. Ensure the shaft diameter can resist cumulative bending deformation caused by repeated impacts.

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10. Limit acceleration and deceleration impact energy within each stroke. Adjust drive parameters to control acceleration and deceleration slopes and avoid rigid mechanical collision during commutation, otherwise the fatigue life will be shortened due to instantaneous overload.

11. Adopt lubrication solutions adapted to high-frequency local reciprocation. Balls move within a small range, making lubricants hard to cover the entire screw evenly. Use high-adhesion and extreme-pressure grease and shorten the regreasing cycle.

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