Top 10 tips for industrial gearbox inspection and maintenance

Paul Boughton

To prolong the operational life of your industrial gearboxes, regular inspections and maintenance is essential. On the other hand, removal of the gearbox for a full inspection and a possible overhaul can cause undesirable lengthy downtime and breaks in shift work or production lines.

Here are ERIKS UK’s Top 10 tips to minimise downtime and ensure your gearbox experiences as long an operational life as possible:

1. Gearbox ratings. Check the gearbox is operating within its manufacturer’s specification for both mechanical and thermal ratings. On many occasions gearboxes are put into an application beyond their design specification and are being driven by an increased input power greater than the maximum recommended.

2. Good housekeeping. It may sound simple but often gearboxes are operating in a dirty and dusty environment. Whilst this is usually unavoidable to a certain extent, it is important to minimise the effects of the workplace environment. This could result in an increased operating temperature or even possible contamination of the gearbox. Therefore industrial gearboxes should be regularly dusted and brushed clean.

3. Shaft seals. Check for oil leaks at the input and output shaft of your gearbox. Leaks indicate that seals have failed, thus allowing dust, debris and water ingress from the environment; and for a potential loss of lubrication. These should be replaced without delay to prevent internal contamination of the gearbox or inadequate lubrication.

4. Breathers. Water, dust and debris should also not be permitted to ingress internally into the gearbox through the breather. They should be the correct type and style, and kept clean at all times to allow the gearbox to breathe with ease.

5. Lubrication. Lubrication should be adhered to the gearbox manufacturer’s specification for type, grade and quantity. Regular renewal should again be carried out to the gearbox manufacturer’s recommendations.

6. Temperature (overheating). Look for signs of overheating, which could include discoloured or burnt exterior paint, or dark oil in the sight glass. Monitor the gearbox temperature on a regular basis and look out for any sudden changes in temperature using an infrared temperature gun.

7. Gear wear/contacts. Check the internal gears via the removal of inspection covers or with the aid of an endoscope. Look for signs of wear such as pitting and spalling (material from the surface of gear tooth flanks being removed). Also inspect the contacts between gear teeth for misalignment using ‘engineers blue’ as this could be indicative of wear in bearings or the bearing housings.

8. Backlash and shaft end play. Use a dial indicator to check for any increase in backlash between the mesh of the gears, and also for any increase in the end play or lift at the input and output shafts. An increase in backlash could be an indication of gear teeth wear, which is not always visible to the naked eye. An increase in shaft end play or lift would indicate wear within the rolling elements of the bearings or even wear in the bearing housings.

9. Vibration Analysis. Many gearboxes operate in a noisy environment, meaning not all variations or increases in gearbox noise can be recorded. Regular vibration analysis of the internal bearings and gears will confirm any significant changes in the internal condition of the gearbox and help prevent any unplanned loss of production.

10. Speak to the Specialist. Whether you need advice or support in inspecting; maintaining and repairing; or replacing your gearbox, bring in the experts who can guide you and help you ensure your site’s gearboxes are working to their maximum operational efficiency.

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