How to lubricate flange slewing bearings

Flange bearings are crucial components in various industrial applications, providing support for rotating shafts while ensuring smooth and efficient movement. Proper lubrication is essential to minimize friction, reduce wear, and extend the bearing’s lifespan. Inadequate lubrication can lead to overheating, premature failure, and increased maintenance costs.Lubricating flange slewing bearings is crucial for their longevity and performance. Here's a comprehensive guide on how to do it correctly.

Flange Bearing Lubrication

1. Understanding Your Bearing:

Bearing Type: Different types (e.g., single-row ball, double-row ball, roller) have slightly different lubrication needs. Consult the manufacturer's specifications.

Seal Type: Bearings often have seals to protect the internal components from contamination. The seal design (e.g., contact seals, labyrinth seals) may influence lubrication procedures.

Operating Conditions: Factors like load, speed, temperature, and environment significantly impact lubrication frequency and grease type.

2. Importance of Proper Lubrication:

Reduced Friction and Wear: Lubrication minimizes friction between the rolling elements (balls or rollers) and the raceways, preventing wear and extending bearing life.

Heat Dissipation: Grease helps dissipate heat generated by friction, preventing overheating and potential damage.

Corrosion Protection: Grease acts as a barrier against moisture and contaminants, protecting the bearing from corrosion.

Sealing: Grease contributes to sealing the bearing, keeping contaminants out and lubricant in.

3. Lubrication Materials (Grease):

Choosing the Right Grease: Select a grease specifically designed for slewing bearings and recommended by the bearing manufacturer. Consider these factors:

Base Oil Viscosity: Higher viscosity for heavy loads and slow speeds, lower viscosity for lighter loads and higher speeds. ISO VG 150 to VG 460 are common ranges.

Thickener Type: Lithium complex greases are a popular choice due to their good water resistance, high-temperature performance, and load-carrying capacity.

Calcium sulfonate greases are also excellent for harsh environments.

Additives: EP (Extreme Pressure) additives for high loads, AW (Anti-Wear) additives for general wear protection, and corrosion inhibitors for rust prevention.

Temperature Range: Ensure the grease's operating temperature range is suitable for your application.

Compatibility: If you're switching grease types, ensure compatibility with the previous grease to avoid issues. It's often best to completely clean the bearing when switching greases.

Never Mix Greases of Different Types: Mixing incompatible greases can lead to thickening, hardening, or separation, which can damage the bearing.

4. Lubrication Procedures:

Frequency: This is highly dependent on the operating conditions and the manufacturer's recommendations. A general guideline is:

Light Duty: Every 100-250 operating hours.

Medium Duty: Every 50-100 operating hours.

Heavy Duty: Every 10-50 operating hours.

Severe Environments: More frequent lubrication may be necessary. Consider environmental factors like dust, water, and extreme temperatures.

Tools:

Grease Gun: A hand-operated or pneumatic grease gun with the correct nozzle fitting for the grease zerks (fittings) on the bearing.

Clean Rags: For wiping excess grease.

Appropriate Safety Gear: Gloves, eye protection.

Steps:

Safety First: Ensure the equipment is safely stopped and secured before lubricating.

Locate Grease Fittings: Identify all the grease zerks (fittings) around the bearing. Slewing bearings typically have multiple grease fittings spaced around their circumference.

Clean the Fittings: Thoroughly clean the grease fittings with a clean rag to remove any dirt or debris. This prevents contaminants from entering the bearing.

Apply Grease Slowly: Attach the grease gun nozzle to a grease fitting and slowly pump grease into the bearing. Avoid over-pressurizing.

Observe Grease Purge: As you add grease, old grease should start to purge out of the seals. Continue pumping until fresh, clean grease appears. This indicates that the entire bearing is adequately lubricated.

Rotate the Bearing: Slowly rotate the bearing through a full revolution while adding grease to each fitting. This helps distribute the grease evenly throughout the bearing.

Wipe Excess Grease: After lubricating all the fittings, wipe away any excess grease that has purged out. Excess grease can attract dirt and contaminants.

Repeat for All Fittings: Repeat steps 4-7 for each grease fitting on the bearing.

Monitor: After initial lubrication, check the bearing temperature and noise levels during operation. If the bearing is running hot or making unusual noises, it may indicate insufficient lubrication or other problems.

5. Important Considerations:

Over-Greasing: Over-greasing can be as harmful as under-greasing. Excessive grease can cause churning, leading to heat buildup and potential damage to the seals. Follow the manufacturer's recommendations for grease quantity.

Under-Greasing: Insufficient lubrication leads to increased friction, wear, and premature bearing failure.

Grease Compatibility: Always use compatible greases. If changing grease types, completely clean the bearing and housing before introducing the new grease.

Cleanliness: Maintain a clean working environment to prevent contamination of the grease and the bearing.

Manufacturer's Instructions: Always consult the bearing manufacturer's specifications for the recommended lubrication type, frequency, and procedure. This information is crucial for maximizing bearing life.

Record Keeping: Keep a record of lubrication dates, grease types used, and any observations (e.g., grease purge quality, bearing temperature). This helps track lubrication performance and identify potential issues.

Inspection: Regularly inspect the bearing for signs of wear, damage, or contamination. Address any issues promptly to prevent further damage.

Professional Assistance: If you are unsure about the lubrication procedure, consult a qualified technician or bearing specialist.

Troubleshooting:

No Grease Purging:

Check for a blockage in the grease fitting.

Ensure the grease gun is working properly.

The bearing may already be full of grease (over-greased).

Excessive Grease Purging:

May indicate seal damage or a very loose bearing.

Grease Purging is Dirty or Discolored:

Indicates contamination or lubricant degradation. Consider more frequent lubrication or a different grease type.

Bearing Runs Hot:

Insufficient lubrication, over-greasing, or bearing damage.

By following these guidelines, you can properly lubricate your flange slewing bearings and ensure their long and reliable operation. Remember that prevention is always better than cure when it comes to bearing maintenance.