Common Problems and Repairs of Slewing Bearings

Slewing bearing, also known as a slewing ring or turntable bearing, is a type of large, heavy-duty bearing designed to accommodate axial, radial, and moment loads simultaneously.Slewing bearings are commonly employed in various industries and applications, including construction equipment (such as excavators, tower cranes, and mobile cranes), wind turbines, antennas, radar systems, tunnel-boring machines, and solar energy systems. Their primary functions are to support loads and provide a stable, smooth, and controlled rotation for the connected structures.

Despite their sturdy design, slewing bearings may encounter several issues over time.In this article, LTZC Bearing will explore these common problems and provide you with suggestions for effective fixes.

Table of Contents:

• The Importance of Repairing Slewing Bearings

• Slewing Bearing Lubrication Problem

• Slewing Bearing Gear Wear Problems

• Slewing Bearings Corrosion and Rust problems

• Slewing bearings Bolt loosening or breakage

• Slewing bearings Gear failure

• Slewing bearing Overheating Problem

• Conclusion

The Importance of Repairing Slewing Bearings

The importance of repairing and maintaining slewing bearings is paramount due to their critical role in various industries, including construction, wind turbines, and cranes. Ensuring timely repairs and proper maintenance of slewing bearings not only promotes safety, optimal performance, and reliability but also extends the service life of these essential components.Slewing bearing refurbishment can result in significant cost savings compared to replacing the entire bearing, especially for large bore slewing bearings. The feasibility of repair or refurbishment greatly depends on the extent of wear or damage. While repairs can be done on smaller slewing bearings, they only become economical when dealing with larger batch sizes. By prioritizing timely repairs, operators can achieve cost savings, increase energy efficiency, and contribute to environmental sustainability by reducing waste and resource consumption.

In summary, investing in routine inspections, maintenance, and repairs of slewing bearings significantly enhances their functionality, ensuring the safe and efficient operation of heavy machinery and equipment, while also taking advantage of potential cost savings associated with refurbishments rather than complete replacements.These comments apply to most Slewing Bearings, such as Four Point Contact Ball Slewing Bearing, Cross Cylindrical Roller Slewing Bearing, Three Row Cylindrical Roller Slewing Bearing,Double Row Ball Slewing Bearings.

Slewing Bearing Lubrication Problem

Proper lubrication is critical for the smooth operation and longevity of slewing bearings. These bearings are exposed to heavy loads, rotational movements, and harsh environmental conditions, making adequate lubrication essential for minimizing friction and wear. However, slewing bearings may encounter various lubrication problems, which, if left unaddressed, can lead to bearing failure and reduced performance. Some common lubrication problems include:

• Insufficient lubrication: An inadequate amount of lubricant can increase friction within the bearing, causing excessive wear, overheating, and potentially leading to premature bearing failure. It is crucial to apply the correct amount of lubricant at the right intervals, as recommended by the manufacturer, to maintain optimal performance.

• Excessive lubrication: Conversely, using too much lubricant can be detrimental to the bearing, as it may cause increased operating temperature and viscosity, hampering the rotation and increasing energy consumption. It is crucial to strike the right balance and follow manufacturer guidelines on the appropriate lubrication volume.

• Incorrect lubricant type: Using an inappropriate lubricant for the specific application, environmental conditions, or the bearing material can cause incompatibility issues or inadequate lubrication performance. It is essential to select a lubricant that is compatible with the materials and operating conditions of the specific slewing bearing.

• Lubricant contamination: The ingress of foreign particles such as dust, dirt, or water can contaminate the lubricant, impairing its effectiveness and leading to damage to the bearing's raceways and rolling elements. It is important to regularly inspect the bearing seals to prevent contamination and maintain cleanliness during lubrication processes.

• Lubricant aging and degradation: Over time, lubricants can degrade due to factors such as oxidation, thermal cycling, or moisture absorption. Aged or degraded lubricants may lose their effectiveness in reducing friction and protecting the bearing, necessitating replacement with fresh lubricant.

Repair suggestions

Proper lubrication is crucial for the smooth operation and longevity of slewing bearings. Lubrication issues can lead to increased friction, wear, overheating, and ultimately bearing failure. Here are some suggestions to address and repair slewing bearing lubrication problems:

• Inspect the lubricant: In case of any lubrication issues, start by examining the lubricant for contamination, discoloration, or degradation. These factors can contribute to a reduction in lubrication performance and increased friction between the rolling elements and raceways.

• Clean the bearing: Thoroughly clean the slewing bearing and remove any old, contaminated, or degraded lubricant. Ensure the bearing assembly and surrounding areas are free from dust, dirt, or any foreign particles that may contaminate the new lubricant.

• Choose the right lubricant: Select a suitable lubricant based on the specific operating conditions, temperature, and load requirements of the slewing bearing. Consult the manufacturer's guidelines or a lubrication expert to ensure you choose an appropriate lubricant for your application.

• Check lubrication methods: Verify if the correct lubrication method is being used, such as manual greasing, oil bath, or automatic lubrication systems. Each method has its advantages and limitations; therefore, it is essential to choose the right method for your specific application.

• Ensure proper lubricant distribution: For an effective lubrication process, the lubricant must be evenly distributed to all bearing surfaces. Check for obstructions or damage in the lubrication delivery system and as needed, clear blockages, repair, or replace damaged components.

• Monitor lubrication intervals: Regular lubrication at correct intervals is vital to prevent problems associated with both excessive and insufficient lubrication. Follow the manufacturer's recommendations and adjust intervals as needed based on operating conditions and environmental factors.

• Train operators: Make sure that equipment operators and maintenance personnel are familiar with the proper lubrication procedures, methods, frequency, and potential issues. Proper training can help prevent problems arising from incorrect lubrication practices.

• Regular inspections: Perform regular inspections of the slewing bearing system to identify any signs of lubrication problems, such as excessive wear, overheating, or noise. Timely detection and addressing lubrication issues can prevent more severe consequences, such as bearing failure or damage to other equipment components.

By following these repair suggestions and implementing a comprehensive maintenance plan, you can minimize lubrication-related problems in slewing bearings and ensure the optimal performance and longevity of these critical components.

Slewing Bearing Gear Wear Problems

Slewing bearings with integrated gears are used in various heavy-duty applications and are prone to gear wear over time. Gear wear can affect the efficiency of power transmission and, in extreme cases, lead to bearing failure. Here are some common gear wear problems and maintenance solutions to address them:

Gear Wear Problems

• Tooth wear: Constant engagement of gear teeth during regular operation can cause gradual wear, leading to reduced gear-tooth thickness and increased backlash.

• Pitting: Repeated contact stress between gear teeth can cause material fatigue, resulting in pits or small indentations on the tooth surface.

• Spalling: A more severe form of pitting, material fatigue leads to the detachment of flakes or fragments from the tooth surface.

• Scoring: Insufficient lubrication or misalignment between slewing bearing gears can cause scoring, resulting in deep scratches or grooves on the tooth surfaces.

• Chipping or tooth breakage: Excessive loads, shock loads, or fatigue can lead to chipping or breakage of gear teeth.

Maintenance Solutions

• Lubrication: Ensure proper gear lubrication to minimize friction and wear. Choose a suitable gear lubricant based on the specific operating conditions, temperature, and load requirements. Regularly inspect the lubricant for contamination, degradation, or discoloration and change it as needed.

• Alignment and backlash adjustment: Inspect the gear alignment and backlash regularly. Misalignment can accelerate tooth wear and increase the risk of damage. Adjust the backlash according to the manufacturer's guidelines to minimize adverse effects on the gear system.

• Load management: Follow the manufacturer's recommendations for load capacity and avoid overloading or abrupt loading on the slewing bearing system. Proper load management helps prevent excessive stress on gear teeth and reduces wear and breakage.

• Teeth surface treatment: Consider surface treatments like nitriding or shot peening to increase the tooth surface hardness and improve wear resistance.

• Regular inspection: Perform routine inspections to detect early signs of gear wear or damage. Check for excessive wear, pitting, spalling, scoring, or chipping, and take corrective actions if necessary.

• Replacement or repair: In severe cases of gear wear or damage, consider repairing or replacing the affected gear components. Repairs might involve grinding or machining to restore the tooth profile, while replacement may require installing a new gear ring or segment.

• Preventive maintenance program: Implement a comprehensive preventive maintenance program that includes inspections, lubrication, alignment, and load management to minimize gear wear and ensure the reliability of the slewing bearing system.

• By applying these maintenance solutions, gear wear problems in slewing bearings can be addressed and mitigated effectively, ensuring optimal performance, extended service life, and reduced downtime for the equipment they support.

Slewing Bearings Corrosion and Rust problems

Slewing bearings operating in harsh environments or exposed to moisture have a high potential for corrosion and rust. This can lead to reduced load capacity, increased friction, and premature bearing failure. To address corrosion and rust problems in slewing bearings, consider the following maintenance solutions:

Maintenance Solutions

Preventive measures: Store and handle slewing bearings in a clean, dry environment and protect them from moisture and contaminants. Use appropriate packaging and protective covers to shield unused bearings or those in transit.

• Lubrication: Regular lubrication not only minimizes friction and wear but also creates a protective barrier against moisture and corrosive elements. Choose a lubricant containing anti-corrosion additives or incorporate corrosion inhibitors to enhance protection.

• Surface treatments: Treat the bearing surfaces with corrosion-resistant coatings, such as zinc plating, nickel plating, or phosphate coatings. These coatings form a protective layer that resists corrosion and surface degradation.

•  Material selection: Opt for slewing bearings made of corrosion-resistant materials, such as stainless steel or alloys specifically designed for harsh environments or corrosive conditions. These materials can prolong bearing life and minimize the risks of corrosion and rust.

• Sealing: Use proper sealing systems to prevent water, dirt, and other contaminants from entering the bearing. Regularly inspect and replace worn or damaged seals to maintain effective protection against corrosion.

• Regular inspections: Conduct routine inspections to identify signs of corrosion or rust. Timely detection of issues allows for corrective actions, preventing further damage and reducing the likelihood of bearing failure.

• Cleaning and corrosion removal: Clean the bearing surfaces to remove dirt, dust, and any corrosion or rust accumulated over time. Use appropriate cleaning solvents and non-abrasive brushes or cloth to avoid damaging the bearing. In case of light surface corrosion or rust, carefully remove it using fine sandpaper followed by a thorough cleaning and lubrication of the bearing.

• Replacement: In the event of severe bearing corrosion or rust, the best course of action may be to replace the slewing bearing entirely. This helps prevent more significant operational issues and ensures the safe and optimal operation of the machinery.

By implementing these maintenance solutions, one can effectively address corrosion and rust problems in slewing bearings, prolonging their service life and ensuring maximum performance in various operating conditions. Implementing a comprehensive preventive maintenance program that includes corrosion protection measures will significantly reduce the risk of bearing failure and subsequent downtime.

Slewing bearings Bolt loosening or breakage

Bolt loosening or breakage in slewing bearings can lead to significant issues, affecting the stability and performance of the bearing and compromising its ability to support loads. To mitigate these problems and prevent potential failures, it's essential to understand the causes and implement effective preventive measures.

Causes of Bolt Loosening or Breakage

• Vibrations: Constant vibrations during operation can cause bolts to gradually loosen over time, potentially leading to breakage under continued stress.

• Impact loads: Sudden or excessive impact loads can exert significant stress on bolts, causing them to weaken or break.

• Improper tightening: Bolts that are not tightened according to the manufacturer's guidelines are more prone to loosening and breakage.

• Material fatigue: Prolonged exposure to cyclic loading can cause material fatigue in bolts, weakening their structure and increasing the likelihood of breakage.

• Corrosion: Corrosion can gradually weaken the bolt material, reducing its strength and increasing the risk of breakage.

Preventive Measures and Solutions

• Regular inspections: Routinely inspect bolts for signs of loosening, breakages, or fatigue. Schedule maintenance checks according to the manufacturer's recommendations or based on the specific operating conditions.

• Proper tightening: Always tighten bolts following the manufacturer's guidelines and use a torque wrench or other specialized tools to ensure accuracy. Adhere to the recommended tightening sequences and torque values to prevent excessive stress on the bolts.

• Addressing vibrations: Monitor vibrations during equipment operation and address any imbalance or misalignment issues that can contribute to excessive stress on the bearing and its components.

• Load management: Operate the equipment within the specified load limits and avoid excessive or sudden impact loads on the slewing bearing system to minimize stress on the bolts.

• Anti-corrosion protection: Apply protective coatings, lubricants, or surface treatments to bolts and other components exposed to potentially corrosive environments to prevent corrosion-related weakening and breakage.

• Material selection: Choose high-quality, high-strength bolts designed to withstand the specific load, temperature, and environmental conditions for the application. Consult the manufacturer for appropriate bolt specifications and materials.

• Replacement: If inspections reveal any bolt loosening or breakage, promptly replace the affected bolts with new high-quality components. Conduct a thorough inspection of the entire bearing assembly to detect any potential damage caused by the loosened or broken bolt.

Through regular inspections, proper installation, and preventive measures, bolt loosening or breakage in slewing bearings can be effectively mitigated. Implementing these solutions will help ensure the safe, reliable, and efficient operation of the machinery and equipment employing slewing bearings.

Slewing bearings Gear failure

Slewing bearings with integrated gears are commonly used in heavy industrial applications to provide both rotational support and power transmission. Gear failure in slewing bearings can significantly affect the performance of the equipment and may lead to more severe consequences, including total bearing failure.we will discuss the causes of gear failure in slewing bearings and the proper actions to address them.

Causes of Gear Failure

• Tooth wear: Prolonged use and constant engagement of gears can lead to gradual wear of gear teeth, reducing tooth thickness and increasing backlash over time.

• Pitting: Frequent contact stress between gear teeth can result in small pits or indentations on the tooth surface due to material fatigue. Pitting can escalate over time and contribute to gear failure.

• Spalling: Spalling occurs when material fatigue leads to the detachment of large flakes or fragments from the tooth surface, exacerbating tooth wear and potentially precipitating gear failure.

• Scoring: Insufficient lubrication or misalignment between slewing bearing gears may cause scoring, or deep scratches, on the tooth surface. Severe scoring can impair the gears' function and lead to failure.

• Chipping or tooth breakage: Excessive loads, shock loads, or fatigue can result in chipping or breakage of gear teeth, causing the gears to malfunction and potentially fail.

• Corrosion: Exposure to harsh environmental conditions or the presence of moisture may cause corrosion on gear teeth, weakening the material and reducing load capacity.

Actions to Address Gear Failure

• Regular inspection: Conduct routine inspections of the slewing bearing gears to detect early signs of gear wear or damage. Check for excessive wear, pitting, spalling, scoring, or chipping, and take corrective actions if necessary.

• Lubrication: Ensure proper gear lubrication to minimize wear and friction between gear teeth. Choose the appropriate lubricant based on specific operating conditions, temperature, and load requirements. Regularly inspect the lubricant for contamination, degradation, or discoloration, and replace it as needed.

• Alignment and backlash adjustment: Inspect the gear alignment and backlash regularly. Proper alignment and backlash adjustment can help reduce tooth wear and prevent gear failure.

• Load management: Follow the manufacturer's recommendations for load capacity and avoid overloading or abrupt loading on the slewing bearing system. Proper load management can help prevent excessive stress on gear teeth and reduce the risk of gear failure.

• Surface treatments: Employ surface treatments, such as nitriding or shot peening, to increase the gear tooth surface hardness and enhance wear resistance. These treatments can help prevent material fatigue and reduce the likelihood of gear failure.

• Replacement or repair: In cases of severe gear wear or damage, consider repairing or replacing the affected gear components. Repair may involve grinding or machining to restore the tooth profile, while replacement may necessitate the installation of a new gear ring or segment.

By taking these actions to address gear failure in slewing bearings, you can significantly enhance the performance and durability of the system, ensuring the optimal functioning of the equipment they support and minimizing costly downtime.

Slewing Bearing Overheating Problem

Overheating in slewing bearings can be a significant issue, potentially leading to premature wear, reduced service life, and even bearing failure. It is crucial to identify the causes of overheating and implement appropriate measures to address and prevent this problem.

Causes of Overheating

• Insufficient or improper lubrication: Lack of adequate lubrication or using the incorrect type of lubricant can lead to increased friction, resulting in elevated temperatures in the bearing.

• Excessive load or preload: Overloading the slewing bearing or applying excessive preload during installation can create additional friction and heat within the bearing components.

• Misalignment: Improper alignment of the slewing bearing can result in uneven distribution of loads, causing increased friction and overheating.

• Contamination: Ingress of foreign particles, such as dirt or dust, can contaminate the bearing, impede lubrication, and increase friction, leading to higher operating temperatures.

• High operating speed: Operating the slewing bearing at speeds beyond the recommended limits generates increased heat due to friction between the rolling elements and raceways.

Solutions for Overheating

• Proper lubrication: Ensure the slewing bearing is adequately lubricated with the correct type of lubricant. Check lubricant levels and conditions regularly, and replace it as needed. Follow the manufacturer's guidelines regarding lubrication intervals and amounts.

• Load and preload management: Monitor and adhere to the manufacturer's recommendations for load limits and preloading procedures. Avoid overloading the slewing bearing and ensure that the preload is set correctly during installation.

• Alignment: Confirm that the slewing bearing is properly aligned and installed according to the manufacturer's guidelines. Proper alignment minimizes stress on the bearing components and reduces the risk of overheating.

• Regular cleaning: Perform routine cleaning and maintenance to help prevent contamination-related issues. Keep the bearing assembly and surrounding area free of dust, dirt, or any foreign particles.

• Speed management: Follow the manufacturer's recommendations on operating speeds to avoid overheating due to excessive friction. Adjust the operating speed as needed to maintain an acceptable temperature range.

• Temperature monitoring: Regularly measure the operating temperature of the slewing bearing, especially during heavy loads or high-speed operations. Implement temperature monitoring systems, such as thermocouples or infrared sensors, to ensure real-time monitoring and track any temperature changes.

• Preventive maintenance: Establish a comprehensive preventive maintenance program that includes inspections, cleaning, lubrication, alignment, and temperature monitoring. This program will help mitigate overheating issues and ensure the optimal performance and service life of the slewing bearing.

By implementing these solutions, you can effectively address and prevent overheating problems in slewing bearings, ultimately enhancing their performance, durability, and lifespan. Regular monitoring and maintenance of these critical components will help ensure smooth operation and minimize downtime.

Conclusion

perational life. Often, premature failures in slewing bearings can be attributed to preventable causes. As such, it is essential to identify the root cause of these failures and implement appropriate preventive measures to avert future complications and reduce the risk of recurrent issues.

In summary, diligent maintenance and repair of slewing bearings play a vital role in securing the longevity and performance of heavy equipment and machinery. By practicing these measures, you can minimize expensive downtime and repairs, ensuring the smooth and efficient operation of your equipment.

If you are looking for reliable slewing bearing manufacturers or suppliers, then we are your best choice. LTZC Bearing can provide various types of slewing bearings. If you need relevant information or help, please contact us.