There are four primary causes for severe vibration in large-scale reducers:

• Thinned tooth flanks (working surfaces), pitting corrosion, uneven wear, and step wear on gear teeth;
• Poor contact or uneven force distribution of gear meshing surfaces, leading to frequent axial movement of gears and subsequent failures such as tooth fracture, gear ring fracture or spoke cracking;
• Loosening between the large gear ring and its hub, or loosening/fracture of connecting bolts, which causes the large gear ring to lose balance;
• Excessively large bearing clearances, severe wear or local melting of the tin alloy in sliding bearings, pitting on rolling bearings, or damage to the cages that secure rolling elements.

The impact and abnormal noises from reducers also stem from four key factors:

• Tooth pitch errors or excessively large gear clearances;
• Insufficient clearances, whistling at the addendum edges of gear teeth, or non-parallel centerlines of transmission gears;
• Eccentric distribution of the gear rotation center;
• Improper selection of lubricating oil, insufficient oil viscosity, or oil shortage.

To resolve the vibration and abnormal noise issues, targeted measures should be taken from the following aspects:

• Inspect the gear flanks and connecting bolts, and replace gears with wear, uneven wear or step wear, as well as damaged gear rings, bolts and other faulty components.
• Check the clearances of support bearings in accordance with the installation drawings, adjust the clearances of bearings with excessively large or small gaps, or replace the damaged bearings entirely.
• Inspect and calibrate the balance of the driving and driven gears.
• Replace the lubricating oil with a product of adequate viscosity that meets the equipment’s operational requirements.