Slewing Bearing for Aerial Work Platform

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In the world of construction, maintenance, and logistics, Aerial Work Platforms (AWPs) – including scissor lifts, boom lifts, and telehandlers – are indispensable for enabling work at height. The safety, stability, and smooth operation of these machines hinge on a critical, often overlooked component: the Slewing Bearing. This specialized bearing is the pivotal heart that allows for the precise and controlled rotation of the platform. At LDB Bearing, we engineer and manufacture slewing bearings that meet the extreme demands of the AWP industry, ensuring operator safety and maximum uptime.

This comprehensive guide delves into everything you need to know about slewing bearings for aerial work platforms, from their fundamental role to selection, maintenance, and why LDB is your trusted manufacturing partner.

What is a Slewing Bearing for an Aerial Work Platform?

A Slewing Bearing for an Aerial Work Platform is a large-diameter, low-profile rotational bearing that connects the machine’s upper structure (the boom and platform) to its lower chassis or turntable. It serves as the fundamental pivot point, enabling 360-degree continuous or limited rotation.

Unlike standard bearings that handle primarily radial or axial loads, a slewing bearing for an AWP is uniquely designed to withstand combined loads. This includes the axial load (the weight of the boom, platform, operators, and tools), the radial load (side forces during movement and wind), and, most critically, the tilting moment – the powerful overturning force generated when the boom is fully extended. Its robust design and integrated gear (for driven rotation) make it a key enabler of the machine’s functionality and reach.

Key Characteristics of a High-Performance AWP Slewing Bearing

Slewing bearings for AWPs are not standard industrial bearings; they are purpose-built for this demanding application with specific features:

  • Compact Cross-Section: AWPs require a low profile to maintain a low center of gravity and a compact machine design. The bearing must deliver high load capacity within a minimal height envelope.
  • High Load Capacity and Rigidity: Safety is paramount. The bearing must have exceptionally high static load ratings, especially for tilting moments, to prevent catastrophic failure under maximum load and extension.
  • Integrated Gear: Most AWP slewing bearings feature a precision-machined internal or external gear that meshes with a pinion gear from the drive motor, enabling powered rotation.
  • Smooth Operation and Low Torque: For precise platform positioning and smooth start-stop motion, the bearing must have low and consistent rotational torque.
  • Robust Sealing: AWPs operate in harsh environments filled with dust, moisture, and debris. Multi-lip, wear-resistant seals are essential to protect the raceway and retain lubricant, ensuring long service life.
  • High Safety Factor: AWP bearings are designed with a high static safety factor (fₛ), typically well above standard industrial minimums, to account for dynamic shock loads, uneven surfaces, and unexpected forces.

Primary Applications in Aerial Work Platforms

Slewing bearings are the rotational core of various AWP types:

  • Articulating Boom Lifts: Enable the rotation of the upper arm and platform, allowing the operator to reach over and around obstacles.
  • Telescopic Boom Lifts: Facilitate the 360-degree rotation of the entire boom assembly for extensive horizontal reach.
  • Scissor Lifts: Used in larger models to allow the entire platform to rotate, increasing work area coverage without moving the base.
  • Telehandlers: Provide the rotation function for the load arm, enabling precise placement of materials.
  • Spider Lifts and Specialized AWPs: Offer the compact yet powerful rotation needed for complex access scenarios.

How Does a Slewing Bearing Work in an AWP?

The working principle involves a harmonious interplay between structure and mechanics:

  1. Load Transmission: The weight and forces from the platform and extended boom are transferred into the upper ring of the slewing bearing.
  2. Load Distribution: These combined loads are distributed through the rolling elements (balls or rollers) positioned in the raceway. The specific geometry of the raceway allows a single-row ball bearing (four-point contact) to efficiently handle axial, radial, and moment loads simultaneously.
  3. Driven Rotation: The rotation drive motor engages its pinion gear with the integrated gear on the bearing. As the pinion turns, it drives the entire upper structure of the AWP (and the upper bearing ring) to rotate relative to the stationary lower chassis.
  4. Structural Integration: The bearing is bolted directly to the machine’s chassis and upper structure via pre-drilled holes, creating a rigid, integral unit that safely transfers all operational loads.

How to Select the Right Slewing Bearing for Your AWP Design

Selecting the correct bearing is a critical engineering decision that dictates machine safety and performance. Partner with LDB’s engineers to analyze:

  1. Load Calculations: The most crucial step. Determine the maximum:
    • Axial Load (Fa): Total dead weight on the platform.
    • Radial Load (Fr): Side forces from wind and dynamic movement.
    • Tilting Moment (M): The primary load, calculated based on the maximum boom extension and load capacity.
  2. Required Safety Factor (fₛ): Establish a minimum static safety factor based on industry standards (e.g., ANSI/SAIA A92.22) and your internal safety protocols. A factor of 1.5 or higher is common.
  3. Bearing Type and Size:
    • Type: Single-row four-point contact ball bearings are most common due to their excellent load versatility and compact design. For heavier-duty models, double-row ball or crossed roller bearings may be considered.
    • Size: Determine the required bore and outer diameter based on structural constraints. The cross-section height is a key limiting factor.
  4. Gearing and Drive Compatibility: Specify internal or external gearing, gear module, and quality to ensure perfect meshing with your drive pinion and smooth power transmission.
  5. Sealing and Lubrication: Define the sealing system (e.g., triple-lip seals for dusty sites) and the lubrication plan, including fitting types and positions for easy maintenance.

The LDB Bearing Ordering Process: Simple and Collaborative

We make procuring reliable AWP slewing bearings straightforward:

  1. Initial Inquiry: Contact us via our website or email with your machine model or preliminary load data.
  2. Technical Collaboration: Our engineering team will work with you to finalize load calculations, select the optimal bearing model, and provide a detailed CAD drawing for your approval.
  3. Quotation and Lead Time: You will receive a formal quotation with pricing, lead time, and terms. We offer both standard and custom-engineered solutions.
  4. Manufacturing and Quality Control: Your order enters our production line, undergoing strict quality checks at every stage—from material certification to final gear inspection.
  5. Delivery and Support: We pack bearings securely for shipping and deliver globally. Our technical support remains available to assist with installation and beyond.

Installation Best Practices for AWP Slewing Bearings

Proper installation is vital for performance and longevity.

  • Surface Preparation: Ensure the mounting surfaces on the chassis and upper structure are clean, flat, and free of burrs or paint. Any imperfection can distort the bearing rings.
  • Handling: Use lifting lugs (if provided) and never lift the bearing by its seals or with slings through the bore.
  • Bolting Procedure: Use only the specified high-strength bolts. Clean threads and apply a recommended thread-locker. Tighten bolts in a star-pattern sequence to the specified torque in several stages to ensure even clamping and prevent ring distortion.
  • Gear Meshing Check: After installation, check the backlash and alignment between the slewing ring gear and the drive pinion, adjusting as per the machine manual.

Routine Maintenance for Long-Term Reliability

Proactive maintenance prevents unexpected downtime.

  • Regular Lubrication: Follow the manufacturer’s schedule for relubricating the raceway. Use a high-quality, extreme-pressure (EP) grease. Purge old grease until clean grease emerges from the seal lips.
  • Bolt Preload Check: Re-torque the mounting bolts after the first 50-100 hours of operation and periodically thereafter (e.g., every 500-1000 hours) as specified in the manual.
  • Visual Inspection: Regularly check for damage to seals, grease leaks, or visible cracks in the bearing or structure.
  • Operational Monitoring: Be alert to any changes like increased noise, vibration, or jerky rotation, which could indicate internal damage or contamination.

LDB Bearing: Your Professional Slewing Bearing Partner for Aerial Work Platforms

Choosing LDB Bearing means partnering with a specialist dedicated to the highest standards of safety and performance.

  • Deep Industry Expertise: We understand the unique dynamics and safety-critical nature of AWP applications.
  • Custom-Engineered Solutions: We don’t just sell standard parts; we design bearings to meet your specific load, size, and performance requirements.
  • Uncompromising Quality: Our bearings are manufactured from superior materials, undergo rigorous heat treatment, and are subject to 100% quality control.
  • Global Support: We serve AWP manufacturers worldwide with reliable products and responsive technical support.

Engineer with Confidence. Build with Safety.
When the stability of your aerial work platform depends on its pivotal component, trust the engineering excellence of LDB Bearing. Contact us today to discuss your project requirements and receive a technical consultation.

Sealed Slewing Bearings:Against Contamination and Premature Failure

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In the demanding world of industrial machinery, the slewing bearing is the critical component that enables robust rotational movement. However, its performance and service life are relentlessly threatened by a silent enemy: contamination. Dust, grit, moisture, and other abrasive particles can infiltrate the bearing raceway, leading to accelerated wear, lubricant breakdown, and ultimately, catastrophic failure. A standard slewing ring is not equipped for this battle. The solution? A Sealed Slewing Bearing-an engineered system designed specifically to protect the bearing’s heart from its operating environment.

At LDB Bearing, we design and manufacture sealed slewing bearings that are not merely components, but integrated protection systems. This in-depth guide will explore what sealed slewing bearings are, why they are indispensable, how their sealing systems work, and the critical factors to consider for your application.

What is a Sealed Slewing Bearing?

A Sealed Slewing Bearing is a large-diameter rotational bearing that incorporates one or more dedicated sealing systems, permanently integrated into its structure, to create a robust barrier between the internal rolling elements/raceways and the external environment. Unlike standard bearings that may have minimal or no sealing, a purpose-built sealed slewing ring features seals that are specifically selected and engineered based on the expected contaminants, operational speeds, and temperature ranges.

The seal is not an afterthought; it is a critical design element, co-engineered with the bearing itself. These seals are typically mounted in machined grooves on the inner and outer rings, forming a dynamic barrier at the interface where the rings rotate relative to each other. The primary goal is to retain the vital lubricating grease inside the raceway while systematically excluding harmful external contaminants.

Why are Sealed Slewing Bearings a Critical Investment?

The cost of a sealed slewing bearing is marginally higher than an unsealed equivalent, but it is one of the most cost-effective investments you can make for equipment reliability. Here’s why:

  1. Dramatically Extended Service Life: Contamination is the leading cause of premature wear in slewing bearings. By preventing abrasive particles from entering the raceway, sealed bearings avoid the pitting, spalling, and micro-fatigue that lead to failure, often doubling or tripling the operational lifespan of the bearing.
  2. Reduced Maintenance Frequency and Cost: A well-sealed bearing retains lubricant effectively, significantly extending relubrication intervals. This translates to less downtime for maintenance and lower consumption of grease.
  3. Enhanced Reliability in Harsh Environments: For machinery operating in sawmills, mining sites, chemical plants, food processing facilities, or offshore, sealed bearings are not an option—they are a necessity. They ensure continuous operation in conditions that would quickly destroy a standard bearing.
  4. Protection of Ancillary Systems: In applications like robotics or medical imaging, bearing failure due to contamination can damage far more expensive surrounding systems. A sealed bearing acts as a reliable safeguard for the entire machine.
  5. Lower Total Cost of Ownership (TCO): When factoring in reduced downtime, lower maintenance labor costs, less grease consumption, and the avoided cost of premature replacement, the sealed bearing offers a significantly lower TCO.

Anatomy of a Seal: Types and Configurations

The effectiveness of a sealed slewing bearing hinges on its seal type. At LDB Bearing, we offer a range of solutions to match specific environmental challenges.

  • Rubber Lip Seals (e.g., NBR or FKM):
    • Description: The most common type, featuring one or more flexible rubber lips that lightly press against the opposing ring.
    • Advantages: Excellent sealing effectiveness against dust and moisture, low friction, and cost-effectiveness.
    • Ideal For: General industrial applications, construction machinery, mobile cranes, and environments with moderate contamination levels.
  • Labyrinth Seals:
    • Description: A non-contact seal consisting of a series of intricate, machined channels that create a tortuous path for contaminants. It is often used in conjunction with grease purging systems.
    • Advantages: No wear, suitable for very high speeds, and highly effective against coarse contaminants when combined with grease.
    • Ideal For: Wind turbine yaw and pitch systems, large rotary tables, and high-speed applications.
  • Composite Seals (Metal-Rubber Laminates):
    • Description: These seals combine a metal armoring for structural rigidity and secure fitment with a rubber sealing element for flexibility and effective contact.
    • Advantages: Extremely robust, resistant to damage during handling and installation, and excellent for withstanding high pressure.
    • Ideal For: Heavy-duty mining equipment, tunnel boring machines (TBMs), and applications with high shock loads.
  • Polyurethane (PU) Scraper Seals:
    • Description: A very tough and durable seal designed to physically scrape off heavy, sticky contaminants.
    • Advantages: Exceptional resistance to abrasion and tearing.
    • Ideal For: Severe environments like mining, steel mills, and concrete processing where mud, clay, or coarse abrasives are present.

Configuration: Seals can be installed on one side (typically the top) or, for maximum protection, on both sides of the bearing.

Key Applications Demanding Sealed Slewing Bearings

Any application exposed to contaminants, moisture, or where reliability is paramount is a candidate for a sealed slewing bearing.

  • Construction & Mining: Excavators, crawler cranes, and mining shovels are constantly exposed to abrasive dust and mud.
  • Agriculture: Harvesters, tractors, and irrigation systems face a combination of dust, crop residue, and humidity.
  • Food & Beverage Processing: Bearings must be sealed to prevent product contamination and to withstand frequent, aggressive washdowns with corrosive cleaning agents.
  • Marine & Offshore: Deck cranes, winches, and propulsion systems require seals that resist saltwater corrosion and high humidity.
  • Wind Energy: Sealed yaw and pitch bearings are critical for protecting against moisture ingress and particulate matter over decades of operation.
  • Wastewater Treatment & Recycling: Scrapers, aerators, and separators operate in highly abrasive and corrosive slurry environments.

How to Select the Right Sealed Slewing Bearing

Choosing the correct sealed bearing requires a systematic analysis of both the mechanical loads and the environmental conditions.

  1. Analyze the Contaminant: Identify the primary threat: is it fine dust, coarse sand, liquid water, chemical splashes, or a combination? This is the single most important factor in seal selection.
  2. Determine the IP (Ingress Protection) Rating Needed: The IP rating system (e.g., IP65, IP67) provides a standard for defining the level of sealing effectiveness against solids and liquids. Specify the required rating for your application.
  3. Evaluate Loads and Bearing Type: Calculate the axial, radial, and moment loads as you would for any slewing bearing. Select the bearing type (single-row ball, double-row ball, crossed roller) that meets these load requirements.
  4. Consider Operational Parameters:
    • Speed: Rubber lip seals are speed-limited; labyrinth seals are ideal for high speeds.
    • Temperature: Ensure the seal material (NBR, FKM, etc.) is compatible with your operating temperature range.
    • Chemical Exposure: Verify the seal material’s resistance to any oils, solvents, or cleaning agents it will encounter.
  5. Plan for Maintenance: Even sealed bearings require relubrication. Ensure the bearing is fitted with standard grease fittings (zerk fittings) and, for large diameters, relief plugs to purge old grease.

Installation and Maintenance Best Practices for Sealed Bearings

A sealed bearing can be compromised by poor handling. Follow these guidelines to ensure longevity.

  • Installation:
    • Handle with Care: Never use sharp tools to handle the bearing, and avoid prying against the seal lips, as this can cause permanent damage.
    • Protect During Installation: Cover the bearing during assembly to prevent welding spatter, chips, or dirt from settling on and damaging the seals.
    • Avoid Distortion: Ensure mounting surfaces are flat and clean. Use the correct bolt torque and a cross-bolting sequence to prevent ring distortion, which can break the seal’s contact.
  • Maintenance:
    • Regular Visual Inspection: Check seals for signs of cuts, hardening, cracking, or deformation.
    • Follow a Lubrication Schedule: Use the recommended grease and relubricate according to the schedule. The act of pumping new grease helps to purge any microscopic contaminants that may have breached the primary seal.
    • Listen and Monitor: Be alert to any changes in operational noise or increased rotational torque, which could indicate seal failure and subsequent bearing damage.

LDB Bearing: Your Partner in Advanced Sealing Solutions

At LDB Bearing, we don’t just add a standard seal to a catalog bearing. We provide engineered sealing solutions.

  • Application-Specific Recommendations: Our engineering team works with you to analyze your operating environment and recommend the optimal seal type and configuration.
  • Custom Seal Integration: We can design and machine custom seal grooves to accommodate specialized or multi-stage sealing systems for the most extreme applications.
  • High-Quality Materials: We use only certified, wear-resistant seal materials to ensure long-term performance.
  • Complete Bearing-Seal System Validation: We test and validate the performance of the integrated bearing and seal system to ensure it meets your reliability targets.

Don’t Let Contamination Control Your Equipment’s Uptime.
The choice of a sealed slewing bearing is a proactive step towards maximizing productivity and minimizing unplanned downtime. For a technical consultation and to select the perfect sealed slewing bearing for your application, contact the LDB Bearing team today. Let us help you build a more reliable, durable, and profitable machine.

Emergency Replacement of Slewing Bearings：LDB Bearing’s Stock & Service

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When mission-critical equipment grinds to a halt due to a failed Slewing Bearings, every minute counts. Downtime isn’t just an inconvenience; it’s a direct drain on productivity, profitability, and project timelines. At LDB Bearing, we operate on a simple, unwavering principle: Your emergency is our priority. That’s why we maintain one of the industry’s most extensive and strategically managed inventories of pre-engineered slewing rings, ready for immediate deployment to get your operations back online with minimum delay.

We recognize that industries like mining, heavy construction, port logistics, and energy generation cannot afford to wait weeks or months for a custom-manufactured bearing. The clock is always ticking. Our Emergency Response Slewing Ring Program is engineered specifically for this scenario, offering a robust selection of the most in-demand sizes, types, and models for same-day or next-day dispatch to destinations worldwide.

The LDB Bearing Emergency Stock Advantage: Speed Meets Precision

Our emergency stock is not merely a collection of standard parts; it is a carefully curated inventory based on decades of field data and failure analysis. We stock the components most likely to be needed for urgent replacements across a vast array of machinery.

Our readily available stock includes:

  • Gear Types: External gear, internal gear, and non-geared (smooth) versions.
  • Structural Types & Load Capacities:
    • Single-Row Four-Point Contact Ball Bearings: The versatile workhorse for applications requiring a compact design that can handle combined axial, radial, and moment loads. Ideal for mobile cranes, excavators, and rotary platforms. (Axial Load Capacity: Up to 800 kN)
    • Double-Row Ball Slewing Bearings: For higher load demands and greater rigidity, offering superior performance in applications like stacker-reclaimers and larger aerial work platforms. (Axial Load Capacity: Up to 1,500 kN)
    • Crossed Cylindrical Roller Bearings: The premier choice for applications demanding extreme precision, high rigidity, and minimal rotational friction, such as robotic welding positioners and precision index tables. (Axial Load Capacity: Up to 1,200 kN)
  • Size Ranges:
    • Outer Diameter (OD): From a compact 400 mm to a substantial 2,000 mm.
    • Cross-Section: Ranging from 50 mm to 120 mm, catering to various structural constraints.
  • Material & Manufacturing Standards: Every in-stock bearing is manufactured from certified 42CrMo4 or 50Mn high-strength alloy steel. The raceways are induction hardened to a depth of 55-60 HRC, ensuring exceptional wear resistance and fatigue life. All units conform to ISO 9001:2015 quality management standards and are engineered to meet or exceed DIN, ABEC, and other relevant international specifications.

Guaranteed Compatibility with Major OEM Machinery

A critical factor in a swift replacement is guaranteed compatibility. Our inventory is meticulously mapped to ensure direct interchangeability with common and critical models from leading global OEMs, including but not limited to:

  • Excavators & Mining Shovels: Komatsu, Caterpillar, Hitachi, Liebherr, Volvo
  • Mobile & Crawler Cranes: Terex, Tadano, Demag, SANY, Zoomlion
  • Aerial Work Platforms (AWPs): JLG, Genie, Skyjack, Haulotte
  • Construction & Earthmoving: Bobcat, Doosan, Case
  • Wind Turbine Yaw & Pitch Systems: For critical maintenance and repair operations.

Each bearing in our stock is cross-referenced with OEM part numbers. If you provide the machine model and the original part number, we can often confirm compatibility within the hour.

Value-Added Ready-to-Ship Specifications

To ensure a true “plug-and-play” experience, every emergency stock slewing ring from LDB is delivered ready for installation:

  • Pre-lubrication: Filled with high-performance, extreme-pressure (EP) lithium complex grease suitable for a wide range of operating temperatures.
  • Integrated Sealing: Equipped with durable, multi-lip NBR or wear-resistant polyurethane seals to protect the raceway from contamination from day one.
  • Mounting Hardware: All units come with pre-drilled and tapped mounting holes. High-strength, grade 10.9 or 12.9 mounting bolt kits are available as an optional, add-on item for ultimate convenience.
  • Surface Protection: Coated with an anti-corrosive storage lubricant to prevent rust during transit and storage.

Express Customization: When a Perfect Match is Not in Stock

We understand that sometimes a perfect match may not be sitting on our shelf. In such cases, our Rapid Modification Service provides a swift alternative to full custom manufacturing.

  • Custom Bore & Hole Machining: We can often modify the internal diameter (ID) or mounting hole pattern of an in-stock unit to fit your specific requirements. This service can turn a near-match into a perfect fit within 24-72 hours.
  • Special Seal & Lubrication Kits: For extreme environments (e.g., high-temperature, chemically exposed, or marine applications), we can provide and install specialized seal kits or high-performance greases.

Industries and Applications We Serve in Crisis

Our emergency stock is strategically selected to support the most downtime-sensitive industries:

  • Heavy Construction & Mining: Excavators, shovels, draglines, concrete pump trucks.
  • Material Handling & Logistics: Port cranes, container handlers, stacker-reclaimers, automated guided vehicles (AGVs).
  • Energy Sector: Wind turbine repair (yaw and pitch systems), hydraulic power generation equipment.
  • Aerospace & Defense: Radar antenna pedestals, missile launch systems, turret platforms.
  • Manufacturing & Robotics: Heavy-duty welding positioners, palletizers, large rotary indexing tables.
  • Marine & Offshore: Deck cranes, winches, propulsion systems.

The LDB Bearing Emergency Procurement Process: How to Get Your Bearing Fast

We have streamlined our process to be as fast and frictionless as possible.

Step 1: Contact Us Immediately
Call our 24/7 emergency hotline or send a detailed email to our dedicated emergency response team.

Step 2: Provide Critical Information
To enable a rapid and accurate match, please provide:

  • Machine manufacturer, model, and serial number (if available).
  • Original slewing ring part number and/or a detailed engineering drawing.
  • Clear description of the failure mode (e.g., spalling, brinelling, cracked gear tooth).
  • Your required urgency level: Standard (24-72 hrs), Urgent (24-Hour), or Critical (Same-Day/Express).
  • Your full shipping address for an immediate quotation.

Step 3: Engineering Validation & Dispatch
Our engineering team will perform a rapid compatibility and load capacity cross-check. Once confirmed, the bearing is allocated to your order, and our logistics team prepares it for immediate dispatch via our global network of partners (DHL, FedEx, or dedicated freight forwarders).

Why Trust LDB Bearing With Your Critical Repair?

  • Proven Reliability: Our bearings are not just “compatible”; they are engineered to the highest standards, often outperforming the original parts in terms of material quality and heat treatment.
  • Global Logistics Network: With warehouses in Asia, Europe, and North America, we can ensure the fastest possible transit time to your location, wherever you are.
  • Technical Expertise: You are not just talking to a salesperson. Our emergency team includes application engineers who understand the mechanics behind the failure and can provide technical support for installation and troubleshooting.
  • A True Partnership: We see ourselves as an extension of your maintenance team, committed to restoring your productivity with speed, reliability, and unwavering support.

Don’t Let a Failed Bearing Stop Your World.
When downtime costs you money by the minute, waiting is not an option. Contact LDB Bearing now for a guaranteed rapid response.

What is Flanged Slewing Bearings?

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At LDB Bearing, we understand that the heart of any robust rotational system is a reliable slewing bearing. Among the various designs available, flanged slewing bearings stand out for their unique advantages in simplifying assembly, enhancing structural integrity, and improving performance. This in-depth guide will explore what flanged slewing bearings are, their key benefits, common applications, and how to select and maintain them for optimal results.

What is a Flanged Slewing Bearing?

A flanged slewing bearing is a large-diameter rotational bearing that incorporates one or more integrated flanges on its inner or outer ring. Unlike standard slewing rings that have a simple rectangular cross-section, a flanged version features a protruding rim that runs circumferentially around the bearing’s profile.

This flange is not an add-on; it is a monolithic part of the bearing ring, manufactured from a single forged or rolled steel blank. It is meticulously machined to provide a precise and robust mounting surface. The primary function of this flange is to serve as an alternative or supplementary mounting point, offering designers greater flexibility and security when integrating the bearing into a machine’s structure. These bearings are engineered to handle combined loads—simultaneous axial, radial, and tilting moment forces—making them indispensable in heavy-duty and precision applications.

Key Design Features and Advantages of Flanged Slewing Bearings

The incorporation of a flange transforms the bearing from a simple component into a multifaceted structural element. Here are the primary advantages that make flanged slewing bearings a preferred choice for engineers:

  • Simplified Assembly and Integration: The flange provides a straightforward and secure mating surface. This can drastically reduce the complexity of the host structure, as there is no need to machine intricate steps or shelves to seat a standard bearing. It simplifies the design process and lowers manufacturing costs for the final equipment.
  • Enhanced Mounting Stability and Rigidity: By offering an additional vertical mounting surface, the flange resists forces that could cause the bearing to shift or “walk” within its housing. This is particularly crucial in applications with high tilting moments or shock loads, as it ensures the bearing and the structure act as a single, rigid unit.
  • Improved Seal Protection: The flange can act as a natural shield for the bearing’s integral seals. By positioning the flange strategically, it can deflect debris, chips, or other contaminants away from the primary seal lips, significantly extending seal life and protecting the internal rolling elements and raceways from premature wear.
  • Versatile Mounting Configurations: Flanges can be designed on the inner ring, outer ring, or even both rings simultaneously. This allows for unparalleled design flexibility. For example, an outer ring flange can be used to bolt onto a stationary base, while the inner ring rotates with the machinery above.
  • Space Optimization: In some compact designs, the flange can serve a dual purpose, acting as both a mounting feature and a gear teeth carrier (for internally or externally geared bearings), saving valuable space and reducing the component count.

How Flanged Slewing Bearings Work: The Mechanics of Rotation and Load Distribution

Understanding the fundamental working principle is key to appreciating their design. A flanged slewing bearing operates on the same core principle as any slewing ring: it facilitates rotation by using rolling elements (balls or rollers) that run along precision-machined raceways between two concentric rings.

  1. Load Transfer Path: The unique role of the flange is to alter and improve the load transfer path. When operational loads (axial, radial, moment) are applied to the rotating structure, these forces are transmitted into one of the bearing rings. The rolling elements then distribute these loads evenly across the raceways and into the opposite ring. The flange, being integrally mounted to the host structure, provides a vastly enlarged and more robust connection point. This ensures that these immense forces are dissipated efficiently into the machine’s framework without causing localized stress concentrations that could lead to failure.
  2. Creating a Unified Structure: Essentially, the flange “locks” the bearing into the structure. This transforms the assembly from a simple “component-in-a-housing” into a single, unified, and highly rigid mechanical system. The bearing doesn’t just sit in the machine; it becomes an integral, load-bearing part of the machine itself. This is critical for maintaining alignment, preventing fretting corrosion at the mounting interfaces, and ensuring precise and repeatable rotation under load.

Common Applications Across Industries

The unique benefits of flanged slewing bearings make them suitable for a wide array of industries and machinery. You will typically find them in applications where precision, reliability, and structural simplicity are paramount.

  • Robotics and Automation: Robotic arms and rotary indexing tables use flanged bearings for their high rigidity and precise mounting, which are essential for repeatable accuracy.
  • Medical Equipment: CT scanners and MRI machines rely on them for smooth, quiet, and absolutely reliable rotation under heavy, precise loads.
  • Industrial Turntables: Assembly lines, welding positioners, and material handling turntables utilize flanged bearings for their ease of installation and robust load capacity.
  • Renewable Energy: While the main bearing in a wind turbine nacelle is typically non-flanged, flanged slewing rings are often used in solar tracker systems and yaw drives for their straightforward mounting to support posts.
  • Construction and Mining Equipment: They are used in compact machinery, conveyor swingers, and drill rigs where the flange provides the necessary stability to withstand harsh operating conditions.

Selecting the Right Flanged Slewing Bearing

Selecting the correct flanged slewing bearing is a critical process that determines the performance and longevity of your application. At LDB Bearing, we recommend a systematic approach:

  1. Load Capacity Analysis: The first step is to calculate all the forces acting on the bearing. This includes the axial load (along the axis of rotation), radial load (perpendicular to the axis), and the tilting moment (overturning force). Our technical team can help you analyze these loads to determine the required static (C0) and dynamic (C) load ratings.
  2. Flange Configuration: Decide whether you need a flange on the inner ring, outer ring, or both. This decision is driven by your machine’s design—which part is stationary and which part rotates, and how the bearing will be housed.
  3. Gearing Requirements: Determine if you need a geared bearing. Flanged bearings can be manufactured with internal or external gear teeth on the non-flanged ring to accommodate a drive pinion for powered rotation.
  4. Size and Dimensions: Specify the required bore diameter, outer diameter (including the flange), and overall height. The number, size, and location of bolt holes on both the main mounting surface and the flange are also critical design parameters.
  5. Sealing and Lubrication: Choose the appropriate seal type (e.g., rubber seals for general industry, polyurethane for abrasive environments) based on your operating environment. Also, specify the lubrication fitting types and positions for easy maintenance.
  6. Environmental Factors: Consider exposure to elements like temperature extremes, corrosive chemicals, or seawater. These factors will influence the material selection (e.g., standard 42CrMo4 steel or corrosion-resistant variants) and surface treatment.

Installation and Maintenance Best Practices

Even the best-designed bearing will fail prematurely if installed or maintained incorrectly.

  • Installation:
    • Ensure the mounting surfaces are clean, flat, and free of burrs. Any imperfection can distort the bearing rings.
    • Use high-strength bolts, washers, and thread-locking fluid as specified.
    • Tighten the bolts in a star-shaped, cross-bolting pattern to the recommended torque value. This ensures even clamping force and prevents ring distortion.
    • For bearings with a flange, pay special attention to the bolt sequence for both the main and flange mounting holes.
  • Maintenance:
    • Regular Lubrication: This is the most critical maintenance task. Use the correct type and grade of high-performance grease and adhere to a strict relubrication schedule. The interval depends on operating speed, load, and temperature.
    • Bolt Preload Check: After the first 100 hours of operation, re-check the torque on all mounting bolts, as settling may occur. Perform periodic checks thereafter.
    • Visual Inspection: Regularly inspect for signs of wear, damage to seals, grease leakage, or corrosion.
    • Monitor Performance: Be alert to any changes in operation, such as increased noise, vibration, or rotational resistance, which could indicate internal damage.

Why Choose LDB Bearing for Your Flanged Slewing Bearing Needs?

At LDB Bearing, we are not just suppliers; we are your engineering partners. Our flanged slewing bearings are manufactured to the highest international quality standards, ensuring reliability in the most demanding applications.

  • Custom Engineering: We specialize in providing custom-engineered solutions. We can design and manufacture a flanged slewing bearing to your exact specifications, including unique flange profiles, special seal arrangements, and custom gear geometries.
  • Superior Quality Control: From material forging and heat treatment to final machining and assembly, every step of our manufacturing process is rigorously controlled to guarantee dimensional accuracy, superior metallurgy, and long service life.
  • Global Support: With a global supply chain and technical support network, we are equipped to serve clients worldwide, providing expert advice and timely delivery.

Ready to Optimize Your Design? If you are designing a new machine or upgrading an existing one, consider the structural and performance benefits of a flanged slewing bearing. Contact the LDB Bearing team today for a technical consultation and let us help you select the perfect bearing solution for your application.

Heavy-Duty Slewing Ring for Mining Machines: The Pivot Point of Productivity

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In the relentless world of mining, where downtime translates directly into massive financial losses and operational hazards, every component must be engineered for extreme performance and unwavering reliability. At the heart of the industry’s most critical machinery—from the colossal excavators that tear into rock faces to the towering stackers that build mountains of ore—lies a component that bears the immense burden of both the machine and its mission: the Heavy-Duty Slewing Ring. This article delves into the critical role of these bearings, their defining characteristics, and best practices for their selection, installation, and maintenance, with a focus on the expertise of leading manufacturers like LDB Bearing.

What is a Heavy-Duty Slewing Ring for Mining Machines?

A Heavy-Duty Slewing Ring（Slewing Bearing） for mining machines is a large-diameter, precision-engineered bearing that facilitates rotational movement under the most demanding conditions imaginable. It serves as the fundamental pivot point between the upper structure (e.g., the house of an excavator) and the undercarriage of heavy mining equipment.

Unlike standard bearings that handle primarily radial or axial loads, a slewing ring is uniquely designed to withstand combined loads—simultaneous axial forces (vertical weight), radial forces (side loads), and massive tilting moments (overturning forces). In a mining excavator, for example, the slewing ring must support the entire weight of the upper structure, boom, and cab, while also resisting the powerful tilting moments generated as the boom extends and the bucket digs into dense material. It is the component that allows for 360-degree rotation, making it indispensable for the functionality of equipment like hydraulic shovels, draglines, stackers, and reclaimers.

These bearings are characterized by their robust construction, large internal gears (or external, depending on the design), and integrated mounting holes that allow them to be directly bolted to the machine’s frame, creating a rigid and highly load-resistant connection.

Characteristics of Heavy-Duty Slewing Rings for Mining Machines

The extreme operating environment of a mine dictates that these slewing rings possess a specific set of characteristics that set them apart from their counterparts in less demanding industries.

  1. Exceptional Load Capacity: The primary feature is an unparalleled ability to handle immense static and dynamic loads. They are designed with high load ratings for axial force, radial force, and, most critically, tilting moment.
  2. Robust Structural Integrity: Manufactured from high-strength, low-alloy steel grades such as 42CrMo4 or 50Mn, these rings are through-hardened or induction hardened to a significant depth (e.g., 55-60 HRC on the raceways) to resist plastic deformation and Brinelling under shock loads.
  3. Advanced Sealing Systems: Mining sites are saturated with abrasive dust, moisture, and other contaminants. Heavy-duty slewing rings are equipped with multi-layered, labyrinth-style seals, often made from wear-resistant materials like polyurethane, to create an impenetrable barrier that keeps grease in and contaminants out.
  4. Integrated Gearing: They feature high-precision, hardened internal or external gears designed to mesh with a drive pinion. The gear teeth are engineered to transmit high torque smoothly and withstand the shock loads inherent in digging and lifting operations.
  5. Optimized Rolling Elements: Depending on the load profile, they may use large-diameter balls or, more commonly, cylindrical rollers. Three-row roller slewing bearings are often the preferred choice for the most extreme applications, as they dedicate one row to axial loads and two rows to radial loads and tilting moments, offering the highest possible capacity.
  6. Corrosion Resistance: While not stainless, the bearings are often treated with specialized surface coatings, such as zinc flake or phosphate coatings, to provide robust corrosion resistance against the elements.
  7. Redundancy and Safety: The design often incorporates safety features, such as additional bolts or alternative load paths, to ensure integrity even in the event of an extreme overload scenario.

LDB-Bearing is a Professional Heavy-Duty Slewing Ring Manufacturer

In a market that demands nothing less than perfection, manufacturers must demonstrate profound engineering expertise and manufacturing capability. LDB Bearing has established itself as a professional and trusted manufacturer of heavy-duty slewing rings for the global mining industry.

LDB’s reputation is built on a foundation of:

  • Advanced Engineering Support: They provide comprehensive technical consultation, performing detailed Finite Element Analysis (FEA) to simulate load conditions and ensure the selected bearing not only fits but thrives in its intended application.
  • Stringent Quality Control: Every step of the manufacturing process, from material sourcing and forging to heat treatment, gear machining, and final assembly, is governed by rigorous quality protocols. This ensures every slewing ring meets international standards for dimensional accuracy and mechanical properties.
  • Customization Capability: Understanding that every mining machine has unique requirements, LDB offers a high degree of customization. This includes bespoke dimensions, specialized sealing solutions, specific gear geometries, and custom lubrication systems.
  • Proven Track Record: Their components are field-proven in some of the world’s most challenging mining operations, a testament to their durability and reliability. This real-world validation is critical for mine operators who cannot afford component failure.

LDB-Bearing Slewing Rings Are Used In

LDB-Bearing’s heavy-duty slewing rings are engineered to be the rotational heart of a wide range of critical mining machinery, including:

  • Hydraulic Excavators and Shovels: Providing the 360-degree slew function that allows the machine to dig, swing, and dump material efficiently.
  • Draglines: Enabling the rotation of the enormous boom and bucket assembly used in surface mining.
  • Stackers and Reclaimers: Facilitating the radial movement required to build stockpiles and reclaim bulk materials like coal and iron ore.
  • Bucket-Wheel Excavators: Allowing the massive superstructure to slew and position the digging wheel accurately.
  • Rotary Crushers and Screens: Providing the continuous rotation needed for processing and sizing mined materials.
  • Tunnel Boring Machines (TBMs): Used in the main bearing assembly to support and rotate the cutting head.

How to Install a Heavy-Duty Slewing Ring for Mining Machines

Proper installation is paramount to achieving the designed service life and performance of the slewing ring. An incorrect installation can lead to premature failure, even with the highest quality bearing.

  1. Preparation and Inspection:
    • Carefully inspect the bearing for any transit damage.
    • Thoroughly clean the bearing’s mounting surfaces and the corresponding machine structure surfaces. Any dirt, burrs, or paint can distort the bearing.
    • Verify the flatness and stiffness of the mounting surfaces as per the manufacturer’s specifications.
  2. Handling and Positioning:
    • Use appropriate lifting equipment and dedicated lifting lugs (if provided) to avoid damaging the bearing. Never lift the bearing using ropes or chains through the bore or over the seals.
    • Carefully lower the bearing into position, ensuring it sits flush against the mounting surface.
  3. Bolting Procedure:
    • Use only the high-strength bolts specified by the slewing ring or machine manufacturer.
    • Clean the bolt threads and apply the recommended thread-locking compound and anti-seize as instructed.
    • Tighten the bolts in a star-pattern sequence (cross-bolting) in several stages (e.g., 30%, 60%, 100% of final torque) to ensure even preload and avoid distorting the rings.
    • Use a calibrated torque wrench to achieve the exact final torque value. This is non-negotiable.
    • After the first 50-100 hours of operation, re-torque all mounting bolts, as initial settling may occur.
  4. Gear Meshing and Drive System:
    • After the bearing is securely mounted, check the backlash and alignment between the slewing ring’s gear and the drive pinion. Adjust according to the machine’s technical manual.

How to Maintain a Heavy-Duty Slewing Ring for Mining Machines

Consistent and correct maintenance is the key to maximizing the operational life of a slewing ring in a harsh mining environment.

  1. Regular Lubrication: This is the single most important maintenance task.
    • Grease Type: Use only the high-performance, extreme-pressure (EP) lithium complex or calcium sulfonate complex grease recommended by the manufacturer.
    • Interval: Follow the manufacturer’s lubrication schedule strictly, which is often based on operating hours. In dusty environments, intervals may need to be shortened.
    • Procedure: Use a high-pressure grease gun. Purge the old grease by pumping new grease through until clean grease emerges from the seal lips. This removes contaminants and wear particles.
  2. Routine Inspection:
    • Visual Check: Regularly inspect for grease leaks, damaged seals, or visible cracks.
    • Bolt Preload Check: Periodically check a sample of bolts for tightness according to the maintenance schedule.
    • Operational Check: Monitor for unusual noises (grinding, clicking) or increased vibration during rotation, which can indicate internal damage.
  3. Cleanliness:
    • Keep the area around the slewing ring, especially the gear and seals, as clean as possible. Build-up of material can force its way past seals and accelerate wear.

Frequently Asked Questions

  1. What is the typical service life of a heavy-duty slewing ring in a mining application?
    There is no single answer, as life depends on load cycles, shock loads, and maintenance. With proper selection and meticulous maintenance, a slewing ring can last for tens of thousands of operating hours, often lasting the life of a major machine rebuild.
  2. How often should the slewing ring be re-lubricated?
    The interval varies but is typically between 100 to 500 operating hours. Always consult the OEM (Original Equipment Manufacturer) and slewing ring manufacturer’s guidelines. Harsher conditions (more dust, water, extreme temperatures) demand more frequent lubrication.
  3. What are the signs of a failing slewing ring?
    Key indicators include: increased rotational resistance or “hang-up,” audible grinding or crunching noises, excessive backlash or play in the rotation, visible grease contamination with metal particles, and cracks in the mounting structure or the bearing rings themselves.
  4. Can a damaged slewing ring be repaired on-site?
    Minor seal replacement can sometimes be done on-site. However, repairs to raceways, gears, or structural components are generally not feasible in the field. Replacement with a new or remanufactured unit is the standard and safest procedure.
  5. Why is bolt preload so critical?
    Correct bolt preload ensures the bearing rings are clamped tightly to the host structure, creating a rigid unit that can properly distribute the massive operational loads. Insufficient preload can lead to loose bolts, fretting corrosion, and catastrophic failure of the bearing or the structure.
  6. What is the difference between a ball and a roller-type slewing ring for mining?
    Single or double-row ball bearings are compact and suitable for moderate loads. Roller bearings (crossed-roller or three-row roller) have a higher load-carrying capacity due to line contact and are the preferred choice for the most severe applications involving shock loads and immense tilting moments, such as in large excavators.
  7. How do I select the right slewing ring for my mining machine?
    Selection requires a detailed analysis of the maximum combined loads (axial, radial, moment), required safety factors, rotational speed, environmental conditions, and gear drive requirements. This is a complex engineering task best performed in close collaboration with the technical team of a reputable manufacturer like LDB Bearing.
  8. What causes “Brinelling” on the raceway, and how can it be prevented?
    Brinelling are indentations on the raceway. It is often caused by shock loads while the bearing is stationary or oscillating slightly without a proper oil film. It can be prevented by ensuring the bearing is adequately lubricated, avoiding excessive static overloads, and, if possible, rotating the bearing slightly before applying heavy loads to distribute the rolling elements.

Comprehensive Selection Guide for Slewing Bearings

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Slewing bearings are critical components in a vast array of machinery, enabling smooth and controlled rotational movement under complex loads. Selecting the correct slewing bearing is paramount to the performance, safety, and longevity of your equipment. This guide provides a detailed, step-by-step approach to understanding and choosing the right slewing bearing for your application.

What is a Slewing Bearing?

A slewing bearing, also known as a slewing ring, turntable bearing, or rotary connection, is a large-scale rolling-element bearing that facilitates rotational movement between two components. Unlike standard bearings that primarily handle radial or axial loads, slewing bearings are uniquely designed to withstand combined loads—simultaneous axial, radial, and tilting moment loads.

The fundamental structure consists of an inner ring and an outer ring, one of which typically features gear teeth (internal or external). Between these rings, rolling elements (balls or cylindrical rollers) are spaced by spacers or cages. Slewing bearings are characterized by their large diameter-to-width ratio and are often manufactured with mounting holes in the rings, allowing for direct bolting to adjacent structures, which simplifies assembly and design.

They are the workhorses in applications where a robust, reliable, and precise rotation is required, forming the fundamental joint in machines from massive cranes to precise solar trackers.

Why the Slewing Bearing Size Chart Is Important?

The slewing bearing size chart is the primary gateway to the selection process. Its importance cannot be overstated for several reasons:

  1. Ensures Physical Compatibility: The most immediate reason is to ensure the bearing fits within the designated space in your machine’s structure. The chart provides critical dimensions like bore diameter, outer diameter, height, and pitch circle diameter of the mounting holes.
  2. Prevents Costly Errors: Selecting a bearing that is too small can lead to catastrophic failure, while one that is too large is a waste of material, weight, and capital. The size chart helps you find a bearing that is “just right,” optimizing both performance and cost.
  3. Facilitates Initial Screening: With hundreds of standard sizes and configurations available, the size chart allows engineers to quickly narrow down potential candidates based on the spatial constraints of their design before diving into complex load capacity calculations.
  4. Standardization and Interchangeability: Size charts for standard bearings allow for easier sourcing and potential interchangeability between different manufacturers, providing flexibility in the supply chain.

Understanding Slewing Bearing Size Chart

A slewing bearing size chart is more than just a list of part numbers and diameters. To use it effectively, one must understand the key parameters typically listed:

  • Model/Part Number: The unique identifier for a specific bearing type and size.
  • Inner Diameter (d): The diameter of the central hole.
  • Outer Diameter (D): The overall outside diameter of the bearing.
  • Height/Thickness (H): The total height or thickness of the bearing assembly.
  • Bolt Circle Diameter (BCD): The diameter of the circle on which the mounting holes are positioned. There are usually two BCDs—one for the inner ring and one for the outer ring.
  • Number and Size of Mounting Holes: Specifies the quantity, diameter, and thread size of the holes for bolts.
  • Gear Information: For geared bearings, the chart will include details like gear type (internal or external), module, number of teeth, and pitch diameter.
  • Rolling Element & Raceway Details: Some detailed charts specify the size and number of balls or rollers.

How to Read It: Cross-reference the required internal and external diameters of your design with the chart. The selected bearing must have a suitable outer diameter to fit your housing and an inner diameter that accommodates any necessary components (e.g., hydraulic swivels, cables) passing through the center.

Common Types of Slewing Bearings

Selecting the correct type is the first major technical decision. The four most common types, defined by their rolling element and raceway configuration, are:

  1. Single-Row Ball Slewing Bearing (Four-Point Contact Ball Bearing): This is the most versatile and common type. A single row of balls contacts the raceways at four points, allowing it to handle combined axial, radial, and tilting moment loads simultaneously. It is compact and highly efficient, ideal for applications like cranes, excavators, and robotic arms.
  2. Double-Row Ball Slewing Bearing: This design features two separate rows of balls. This configuration provides a significantly higher load-carrying capacity, especially for axial loads and tilting moments, compared to a single-row bearing of a similar size. It is often used in heavier-duty applications such as large stacker reclaimers and port cranes.
  3. Crossed Roller Slewing Bearing: In this type, cylindrical rollers are arranged alternately at 90° angles between the inner and outer rings. This configuration allows each roller to handle axial and radial loads directly. They offer very high rotational accuracy and rigidity but typically have lower rotational speeds. They are perfect for applications demanding high precision, such as rotary tables on machine tools, industrial robots, and radar antennae.
  4. Three-Row Roller Slewing Bearing: This is the heaviest-duty option. It utilizes three independent rows of cylindrical rollers—one dedicated to handling axial loads and the other two dedicated to handling radial loads and tilting moments. This design offers the highest possible load capacity and is almost exclusively used in the most demanding applications, such as massive mining shovels and heavy-lift offshore cranes.

Understanding Load Ratings

Load ratings are the heart of the technical selection process. Choosing a bearing based solely on size is a recipe for failure. The key ratings to understand are:

  • Static Load Rating (C₀): This is the load that a bearing can withstand without permanent deformation sufficient to impair operation. It is relevant when the bearing is stationary or oscillating slowly under load. Exceeding the static load rating can cause Brinelling (indentations on the raceways).
  • Dynamic Load Rating (C): This rating represents the constant radial or axial load that a group of identical bearings can endure for a rating life of 1 million revolutions. It is used to calculate the theoretical fatigue life (L10 life) of a bearing under rotation.
  • Static Tilting Moment Rating (M₀): This is the maximum tilting moment the bearing can support while stationary without permanent deformation.
  • Dynamic Safety Factor (fₛ): This is not a load rating but a critical calculated value. It is the ratio of the bearing’s static load capacity to the actual applied static load (fₛ = C₀ / P₀). A minimum safety factor, typically provided by the manufacturer (e.g., 1.25 for cranes, 1.5 for wind turbines), must be maintained to account for dynamic shock loads, uneven load distribution, and other unpredictable operational factors.

How to Use Them: The selection process involves calculating the maximum combined loads (axial force, radial force, and tilting moment) that the bearing will experience in your application. These calculated loads are then compared to the bearing’s rated capacities, ensuring that the static and dynamic safety factors are met.

Popular Brands and Their Size Charts

Several global manufacturers are renowned for their quality and engineering support. While their core product lines are similar, their sizing and part numbering are proprietary.

  1. SKF: A global leader, SKF offers a wide range of standard slewing bearings (e.g., the SBP, SBV, and SBC series) under the “Slewing Bearing and Wire Race” portfolio. Their size charts are comprehensive and integrated into their online selection tools, which help calculate loads and life.
  2. ThyssenKrupp Rothe Erde: A specialist in large-diameter bearings, Rothe Erde is a top choice for heavy industrial and wind energy applications. Their catalogs provide extremely detailed technical data, including load ratings for a vast array of standard and custom sizes.
  3. IMO & IBC (International Bearing Corporation): IBC is a major American manufacturer known for its “W” series of four-point contact ball bearings. Their size charts are widely used as a reference in many industries, particularly in North America.
  4. La Leonessa / Rollix: This manufacturer offers a broad portfolio and is known for its technical expertise. Their catalogs provide clear size charts and load rating tables.

Important Note: While size charts can be compared for physical dimensions, load ratings from different manufacturers are not directly interchangeable. A bearing from Brand A and Brand B with identical physical dimensions can have significantly different load capacities due to differences in heat treatment, material quality, and internal geometry. Always use the load ratings from the specific manufacturer you are sourcing from.

Additional Critical Selection Factors

Beyond type and load ratings, a complete selection must consider these factors:

  • Gear Requirements: Determine if you need a geared bearing (for driven rotation) and whether an internal or external gear is required. The gear module and teeth must be designed to handle the transmitted torque from the pinion.
  • Sealing: Effective sealing is crucial to keep contaminants out and grease in. Standard options often include rubber seals (e.g., NBR). For harsh environments (e.g., marine, food industry), special seals like polyurethane or labyrinth seals may be necessary.
  • Lubrication: Slewing bearings require regular relubrication. The type and number of lubrication fittings (grease nipples) and the presence of lubrication holes and channels are important design considerations. The correct grease type for the operating temperature and speed must be specified.
  • Material and Heat Treatment: Standard bearings are typically made from carbon chromium bearing steel (e.g., 42CrMo4) and hardened. For corrosive environments, materials like stainless steel or coatings like zinc-nickel plating are available. The raceways are almost always induction hardened to a specific depth to withstand high contact pressures.

Installation, Maintenance, and Handling

A perfectly selected bearing will fail prematurely if installed or maintained incorrectly.

  • Handling: Slewing bearings are precision components. They must be stored horizontally and handled with care to avoid drops and impacts that can cause Brinelling.
  • Installation: The mounting surfaces must be flat, rigid, and properly aligned. The bearing must be mounted using high-strength bolts, tightened to the correct preload torque in a cross-bolting sequence. The structure must be designed to have a higher stiffness than the bearing itself.
  • Maintenance: A maintenance schedule must be established for regular inspection and relubrication. The first lubrication interval is often shortly after initial operation to purge any contaminants from the running-in period.

Step-by-Step Selection Procedure

  1. Define Application & Loads: Identify the machine, its function, and calculate the maximum combined loads (axial force Fa, radial force Fr, tilting moment M).
  2. Determine Safety Factor (fₛ): Establish the required static safety factor based on application standards and operational criticality.
  3. Preliminary Size & Type Selection: Use a size chart to find a bearing that fits your spatial constraints. Based on the magnitude of the loads, select a preliminary type (e.g., Single-Row Ball for moderate loads, Crossed Roller for high precision, Three-Row Roller for extreme loads).
  4. Check Load Ratings: With the candidate bearing’s static load ratings (C₀, M₀), verify that the safety factor fₛ = C₀ / P₀ meets or exceeds your requirement.
  5. Specify Accessories & Options: Finalize requirements for gear, seals, lubrication, material, and mounting holes.
  6. Consult a Supplier: For critical applications, always consult with the technical engineering team of your chosen slewing bearing manufacturer. They can perform a detailed verification and offer expert recommendations.

Conclusion

The selection of a slewing bearing is a multifaceted engineering process that balances physical dimensions, load capacity, operational requirements, and environmental factors. By systematically working through this guide—from understanding the basic “what” and “why,” to interpreting size charts and load ratings, and finally considering installation and maintenance—you can make an informed and reliable selection. This ensures the slewing bearing will perform as the robust and dependable heart of your rotating machinery for its entire service life.

A Comprehensive Guide on How to Purchase a Slewing Bearing

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Purchasing a slewing bearing is a critical decision that directly impacts the performance, safety, and longevity of heavy-duty machinery. Unlike standard components, a slewing bearing is a high-precision, integral element that requires careful consideration and a methodical approach. Whether you are an engineer, a procurement specialist, or a project manager, this guide will walk you through everything you need to know to make an informed and successful purchase.

What is a Slewing Bearing?

A slewing bearing, also known as a slewing ring, turntable bearing, or rotary joint, is a large-scale rolling-element bearing that facilitates rotational movement between two components. It is fundamentally different from a standard bearing in its size, design, and functionality. While typical bearings are designed primarily to support radial or axial loads, a slewing bearing is engineered to handle combined loads—simultaneously supporting axial load (parallel to the axis of rotation), radial load (perpendicular to the axis), and tilting moment (a force that attempts to tilt the structure).

Structurally, a slewing bearing consists of an inner ring and an outer ring, one of which usually incorporates gear teeth (internal or external). Between these rings are rolling elements—balls or cylindrical rollers—held in place by spacers or cages. The entire assembly is sealed to retain grease and exclude contaminants, and it features mounting holes on both rings for direct bolting to the surrounding structures, such as a chassis and a boom. This design eliminates the need for complex housing, making it a compact and efficient solution for 360-degree rotation under heavy loads.

Characteristics of Slewing Bearings

Slewing bearings are defined by several key characteristics that set them apart:

  1. High Load-Carrying Capacity: Their primary characteristic is the ability to withstand immense combined loads and moments in a single, compact unit.
  2. Integrated Design: They often come with integrated gear teeth, allowing for direct meshing with a pinion gear to create a compact drive system.
  3. Compact and Space-Saving: By serving as both a bearing and a structural connection point, they simplify machine design and save valuable space.
  4. Sealing and Lubrication: High-quality seals are critical to protect the rolling elements and raceways from dirt, moisture, and debris. They are equipped with grease fittings for regular relubrication to ensure a long service life.
  5. High Precision and Low Starting Torque: Precision manufacturing ensures smooth and controlled rotation with minimal resistance, which is crucial for accurate positioning.

Applications of Slewing Bearings

The versatility of slewing bearings makes them indispensable across a wide range of industries. Common applications include:

  • Construction Machinery: Excavators, cranes, tunnel boring machines, and concrete pump trucks.
  • Wind Power: The yaw and pitch systems in wind turbines, where they enable the nacelle to rotate against the wind and the blades to adjust their angle.
  • Material Handling: Stacker reclaimers, rotary conveyors, and forklifts.
  • Industrial Machinery: Robotic arms, welding positioners, indexing tables, and heavy-duty turntables.
  • Defense and Aerospace: In radar systems, artillery platforms, and missile launchers for precise rotation.
  • Medical Equipment: Advanced medical imaging devices like CT and MRI scanners.

Types of Slewing Bearings

Slewing bearings are categorized based on the arrangement of their rolling elements and raceways. The main types are:

  1. Single-Row Ball Slewing Bearing (Four-Point Contact Ball): This is the most common type. A single row of balls contacts the raceway at four points, allowing it to handle combined axial, radial, and moment loads simultaneously. It is compact and suitable for applications with moderate loads and high rotational speeds.
  2. Double-Row Ball Slewing Bearing: Featuring two separate rows of balls, this type has a higher load-carrying capacity, especially for axial loads and tilting moments, than the single-row type. It offers greater stiffness and stability.
  3. Crossed Roller Slewing Bearing: In this design, cylindrical rollers are arranged crosswise between the inner and outer rings. Each roller is positioned at a 90-degree angle to its neighbor. This configuration provides extremely high rigidity and precision, making it ideal for applications requiring high moment load capacity and precise rotational accuracy, such as robotics and industrial rotators.
  4. Three-Row Roller Slewing Bearing: This is the heaviest-duty option. It uses three independent rows of rollers—one dedicated to axial loads and two dedicated to radial loads. This design is used in the most demanding applications, such as large-scale mining excavators and heavy-lift cranes, where extreme loads are present.

Factors to Consider When Selecting a Slewing Bearing

Choosing the right slewing bearing is a complex engineering task. The following factors must be meticulously analyzed:

  1. Load Analysis: This is the most critical step. You must calculate all the forces acting on the bearing:
    • Axial Load (Fa): The force parallel to the axis of rotation.
    • Radial Load (Fr): The force perpendicular to the axis.
    • Tilting Moment (M): The overturning moment.
    • Dynamic vs. Static Loads: Determine if the bearing will be subject to continuous rotation (dynamic) or primarily static loads with occasional movement.
  2. Gear Requirements: Decide if you need a gear (internal or external) for drive transmission. Specify the gear geometry (module, number of teeth) and quality standard (e.g., DIN, AGMA) based on the required torque and operational smoothness.
  3. Dimensions and Mounting: Define the required bore diameter, outside diameter, height, and the number, size, and grade of mounting holes. Ensure the design allows for proper installation and access to bolts.
  4. Rotational Speed: The operational speed (RPM) influences the selection of rolling elements (balls for higher speeds, rollers for lower speeds) and the sealing and lubrication system.
  5. Environmental Conditions: Consider factors like temperature extremes, exposure to corrosive agents (saltwater, chemicals), presence of abrasive dust, or potential for contamination. This will dictate the need for special seals, coatings, or corrosion-resistant materials.
  6. Precision and Stiffness Requirements: Applications like robotics or radar systems demand high rotational accuracy and minimal deflection, which points towards crossed roller bearings.
  7. Lubrication and Maintenance: Consider the lubrication interval and the ease of access for maintenance. Automatic lubrication systems can be specified for hard-to-reach bearings.

Steps to Purchasing a Slewing Bearing

A structured purchasing process ensures you get the right product at the best value.

  1. Define Your Requirements: Consolidate all the factors from the previous section into a detailed technical specification document. This is your most important tool.
  2. Research and Identify Potential Suppliers: Look for manufacturers with a proven track record in your industry. Evaluate their technical expertise, manufacturing capabilities, quality certifications (e.g., ISO 9001), and reputation.
  3. Request for Quotation (RFQ): Send your detailed specification to multiple shortlisted suppliers. A good RFQ should include load diagrams, dimensional drawings, material and hardness requirements, and expected service life.
  4. Technical Evaluation: Do not base your decision on price alone. Engage in technical discussions with the suppliers. A reputable manufacturer will ask detailed questions and may even suggest design improvements. Review their design calculations and proposed solutions.
  5. Quality and Inspection Protocol: Discuss the quality control measures. Inquire about in-process inspections, final inspection reports, and non-destructive testing methods (like magnetic particle inspection) for the raceways and gears. For critical applications, you may require third-party inspection.
  6. Compare Quotations and Lead Times: Evaluate the total cost, including shipping, taxes, and any special packaging. Balance the cost against the offered quality, warranty, technical support, and production lead time.
  7. Place the Order and Manage Logistics: Once a supplier is selected, place a formal purchase order. Ensure all agreed-upon specifications and inspection criteria are clearly stated. Plan for the logistics of receiving a large, heavy, and often delicate component.
  8. Installation and After-Sales Support: Verify that the supplier provides clear installation guidelines. A reliable partner will offer technical support during installation and provide robust after-sales service for maintenance and troubleshooting.

LDB-bearing: A Reliable Slewing Bearing Manufacturer

When searching for a supplier that embodies quality, reliability, and technical excellence, LDB-bearing stands out as a premier manufacturer. With years of specialized experience in the field, LDB-bearing has built a reputation for producing high-performance slewing bearings that meet the rigorous demands of various global industries.

LDB-bearing’s strength lies in its integrated manufacturing process, which includes advanced heat treatment facilities, precision machining centers, and a stringent quality control system. They offer a wide range of standard and custom-designed slewing bearings, including single-row ball, double-row ball, crossed roller, and three-row roller types. Their engineering team works closely with clients from the design phase to ensure the selected bearing is perfectly optimized for the application, providing solutions that enhance machine performance and durability.

By choosing LDB-bearing, you are not just purchasing a component; you are gaining a partnership with a company committed to delivering superior products, competitive pricing, and exceptional customer service, ensuring your machinery operates at its peak for years to come.

What to Consider When Sourcing a Cross Roller Slewing Bearing: A Precision Buyer’s Guide

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What Is a Cross Roller Slewing Bearing?

A Cross Roller Slewing Bearing is a type of slewing ring that uses cylindrical rollers arranged in alternating 90-degree directions (crossed), allowing it to simultaneously support radial, axial, and moment loads with high precision and rigidity. It is specifically designed for applications where high positioning accuracy, smooth rotation, and minimal backlash are essential.

Unlike traditional ball bearings or three-row designs used in heavy equipment, cross roller slewing bearings shine in precision engineering sectors such as robotics, medical devices, radar systems, and semiconductor production.

Structure and Key Features of Cross Roller Slewing Bearings

Core Design Elements:

Rollers arranged orthogonally to maximize load contact area

Single raceway groove, usually hardened and precision ground

High stiffness and low friction

Compact size compared to other bearing types with similar capacity

Internal or external gear options depending on the drive system

Benefits of Using Cross Roller Slewing Bearings

Superior Rotational Accuracy
Ideal for applications where angular deviation or backlash is unacceptable.

Minimal Elastic Deformation
Thanks to the cross arrangement of rollers, it handles moment loads exceptionally well.

High Load Capacity in All Directions
One compact unit handles axial, radial, and overturning loads—reducing system complexity.

Compact and Lightweight
Perfect for machines where space and weight are critical factors.

When Should You Choose a Cross Roller Slewing Bearing?

Use cross roller slewing bearings when:

High angular positioning accuracy is required

You’re building servo-controlled turntables or robotic bases

The application involves repetitive motion with minimal wear tolerance

The device operates under light to moderate load but with strict precision demands

LDB Cross Roller Slewing Bearing Solutions

LDB, a leading manufacturer and supplier, offers precision-engineered cross roller slewing bearings with the following specifications:

LDB-CR Series – Cross Roller Slewing Bearing

Outer Diameter: 200mm to 1600mm

Gear Type: Internal, external, or non-geared

Precision Class: P5 and above available upon request

Application Areas: Industrial robots, indexing tables, medical scanners, machine tools

LDB bearings are made from 50Mn or 42CrMo and undergo deep quenching for surface hardness and long-term wear resistance.

Key Considerations When Sourcing

Precision Grade and Backlash

Choose P5 or better tolerance levels for high-precision platforms

Minimize backlash through fine grinding and preloading if necessary

Raceway Hardness and Finish

LDB ensures 55–62 HRC hardness with ≤Ra0.8 surface finish on raceways

Lubrication and Sealing

For cleanroom or medical applications, use food-grade or low-volatility lubricants

Optional dust-proof seals for electronics and optics industries

Mounting Style

Most LDB models support both face-mounting and base-mounting configurations

Custom Gear Profile

LDB can customize the gear module, pressure angle, and tooth profile for integration with stepper/servo motors

Application Scenarios

IndustryTypical ApplicationLDB Solution
RoboticsBase joints, rotary axisLDB-CR Series
Medical EquipmentCT/MRI scanner rotationLow-noise, sealed model
SemiconductorWafer handling robotsAnti-static variant
AerospaceAntenna pointing systemsLightweight precision
Machine ToolsIndexing tables, measuring platformsPreloaded low-runout unit

Price Reference for Cross Roller Slewing Bearings

The price of a cross roller slewing bearing varies based on size, precision class, gear type, and material:

Outer Diameter RangePrice Range (USD)Gear Type
200mm–600mm$200 – $800Gearless/Int
600mm–1200mm$800 – $1600External Gear
1200mm+$1600 – $3000+Custom Gear

Bulk orders and OEM customization are available directly from LDB, with volume discounts and technical support included.

Why Source from LDB?

As an experienced manufacturer and supplier, LDB offers:

100% in-house production for quality control

ISO 9001 certified manufacturing

Full traceability for precision-grade bearings

Support for special materials and coatings

3–5 year warranty on precision bearings

LDB’s cross roller slewing bearings are already trusted by customers in Germany, Japan, South Korea, and the U.S. for high-tech manufacturing platforms.

Conclusion

When your application requires ultra-smooth rotation, tight dimensional tolerances, and strong rigidity in a compact form, Cross Roller Slewing Bearings are the optimal choice. From design consultation to post-delivery support, LDB offers reliable precision solutions backed by engineering expertise and global delivery capabilities.

Contact LDB today for technical support, drawings, and a quote on your next cross roller slewing bearing project.

Three-Row Roller Slewing Bearings: Heavy-Duty Rotation for Maximum Load Performance

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What Is a Three-Row Roller Slewing Bearing?

A three-row roller slewing bearing is a high-load capacity bearing that consists of three separate raceways, each with its own roller set—one for axial loads, one for radial loads, and one for tilting moments. This design allows the loads to be distributed across three rows of rollers, significantly increasing load capacity and rigidity compared to single-row or double-row designs.

Three-row slewing bearings are commonly used in ultra-heavy-duty applications such as harbor cranes, offshore drilling platforms, ladle turrets, bucket wheel excavators, and wind turbine yaw systems.

Key Advantages of Three-Row Roller Slewing Bearings

Extreme Load Carrying Capacity

Each roller row is optimized for a specific load type, which ensures maximum utilization of the bearing’s internal structure. This makes it the preferred choice for equipment that endures continuous high stress.

High Stability and Rigidity

The separated load paths minimize raceway deformation and provide strong resistance against overturning moments, enabling precise and safe rotation under challenging conditions.

Extended Service Life

Due to even stress distribution and optimized material usage, these bearings offer improved fatigue life and durability—even under dynamic loads and variable speeds.

Versatility in Harsh Environments

Engineered with heavy sealing systems and surface treatments, they perform reliably in marine, mining, and steel plant conditions with exposure to heat, dust, and corrosive media.

Where Are They Used?

IndustryEquipment
Port LogisticsContainer cranes, ship loaders
Mining & ExcavationBucket wheel excavators, stackers
Offshore Oil & GasPipe handling equipment, drilling platforms
MetallurgyLadle turrets, slab turning devices
Wind PowerLarge yaw systems for offshore turbines

LDB’s Three-Row Slewing Bearing Portfolio

LDB is a top-tier manufacturer and global supplier of three-row roller slewing bearings, offering standard and custom-engineered solutions for large-scale equipment.

Product Specifications:

Outer diameter range: 800 mm – 5000 mm

Roller diameters: customized per application

Raceway precision: CNC-ground hardened steel

Gear types: external gear, internal gear, or gearless

Sealing: double-lip contact seals with grease retention

Surface treatment: black oxide, phosphate, or epoxy painting

All bearings are factory-lubricated and tested under simulated load conditions.

Typical Pricing and Considerations

Three-row slewing bearings involve higher raw material and machining costs due to their size and complexity. Pricing varies with:

Size and raceway design

Gear module and tooth hardness

Seal grade and coating requirement

Additional testing or documentation (e.g., ABS, DNV)

Typical Price Range: USD $2,000 – $20,000 per unit
For specialized offshore or certified products, costs may exceed this range.

To get a tailored quote, visit www.ldb-bearing.com.

Engineering & Customization Services

LDB offers full technical support from design to deployment:

Load simulation and life prediction (L10h method)

Material selection and gear customization

Bolt pattern optimization for heavy bases

Special packaging for offshore or export use

Clients receive full documentation including 2D/3D drawings, heat treatment certificates, and inspection reports.

Why Choose LDB?

Decades of experience in heavy-equipment bearings

In-house forging, heat treatment, and assembly

Exported to 40+ countries for major EPC and OEM projects

Flexible lead times and responsive technical team

LDB’s three-row roller slewing bearings are trusted by global manufacturers of cranes, excavators, and renewable energy systems.

Installation Tips

Ensure full support surface under bearing

Apply uniform torque across all mounting bolts

Use calibrated torque tools and recheck tension after 100 hours

Re-grease according to duty cycle and environmental exposure

Conclusion

Three-row roller slewing bearings are the ultimate choice for ultra-heavy load applications where safety, strength, and reliability cannot be compromised. Their robust construction and load-specialized raceways make them essential for mega-projects worldwide.

LDB delivers these high-capacity bearings with complete technical assurance, backed by global service and precision manufacturing. Let us power your next heavy-duty innovation—start at www.ldb-bearing.com.

Three-Row Roller Slewing Bearings: Heavy-Duty Rotation for Maximum Load Performance

What Is a Three-Row Roller Slewing Bearing?

A three-row roller slewing bearing is a high-load capacity bearing that consists of three separate raceways, each with its own roller set—one for axial loads, one for radial loads, and one for tilting moments. This design allows the loads to be distributed across three rows of rollers, significantly increasing load capacity and rigidity compared to single-row or double-row designs.

Three-row slewing bearings are commonly used in ultra-heavy-duty applications such as harbor cranes, offshore drilling platforms, ladle turrets, bucket wheel excavators, and wind turbine yaw systems.

Key Advantages of Three-Row Roller Slewing Bearings

Extreme Load Carrying Capacity

Each roller row is optimized for a specific load type, which ensures maximum utilization of the bearing’s internal structure. This makes it the preferred choice for equipment that endures continuous high stress.

High Stability and Rigidity

The separated load paths minimize raceway deformation and provide strong resistance against overturning moments, enabling precise and safe rotation under challenging conditions.

Extended Service Life

Due to even stress distribution and optimized material usage, these bearings offer improved fatigue life and durability—even under dynamic loads and variable speeds.

Versatility in Harsh Environments

Engineered with heavy sealing systems and surface treatments, they perform reliably in marine, mining, and steel plant conditions with exposure to heat, dust, and corrosive media.

Where Are They Used?

IndustryEquipment
Port LogisticsContainer cranes, ship loaders
Mining & ExcavationBucket wheel excavators, stackers
Offshore Oil & GasPipe handling equipment, drilling platforms
MetallurgyLadle turrets, slab turning devices
Wind PowerLarge yaw systems for offshore turbines

LDB’s Three-Row Slewing Bearing Portfolio

LDB is a top-tier manufacturer and global supplier of three-row roller slewing bearings, offering standard and custom-engineered solutions for large-scale equipment.

Product Specifications:

Outer diameter range: 800 mm – 5000 mm

Roller diameters: customized per application

Raceway precision: CNC-ground hardened steel

Gear types: external gear, internal gear, or gearless

Sealing: double-lip contact seals with grease retention

Surface treatment: black oxide, phosphate, or epoxy painting

All bearings are factory-lubricated and tested under simulated load conditions.

Typical Pricing and Considerations

Three-row slewing bearings involve higher raw material and machining costs due to their size and complexity. Pricing varies with:

Size and raceway design

Gear module and tooth hardness

Seal grade and coating requirement

Additional testing or documentation (e.g., ABS, DNV)

Typical Price Range: USD $2,000 – $20,000 per unit
For specialized offshore or certified products, costs may exceed this range.

To get a tailored quote, visit www.ldb-bearing.com.

Engineering & Customization Services

LDB offers full technical support from design to deployment:

Load simulation and life prediction (L10h method)

Material selection and gear customization

Bolt pattern optimization for heavy bases

Special packaging for offshore or export use

Clients receive full documentation including 2D/3D drawings, heat treatment certificates, and inspection reports.

Why Choose LDB?

Decades of experience in heavy-equipment bearings

In-house forging, heat treatment, and assembly

Exported to 40+ countries for major EPC and OEM projects

Flexible lead times and responsive technical team

LDB’s three-row roller slewing bearings are trusted by global manufacturers of cranes, excavators, and renewable energy systems.

Installation Tips

Ensure full support surface under bearing

Apply uniform torque across all mounting bolts

Use calibrated torque tools and recheck tension after 100 hours

Re-grease according to duty cycle and environmental exposure

Conclusion

Three-row roller slewing bearings are the ultimate choice for ultra-heavy load applications where safety, strength, and reliability cannot be compromised. Their robust construction and load-specialized raceways make them essential for mega-projects worldwide.

LDB delivers these high-capacity bearings with complete technical assurance, backed by global service and precision manufacturing. Let us power your next heavy-duty innovation—start at www.ldb-bearing.com.

Three-Row Roller Slewing Bearings: The Ultimate Load-Bearing Powerhouse

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What is a Three-Row Roller Slewing Bearing?

A Three-Row Roller Slewing Bearing is a high-capacity rotational bearing system that features three separate rows of rollers—each row designed to carry different types of load. Unlike single or double-row ball bearings, this design separates axial, radial, and tilting moment loads across three distinct paths, dramatically increasing the load-bearing capacity, stiffness, and operational safety.

These bearings are the largest and most robust slewing rings available in the industry and are widely used in heavy-duty applications that demand uncompromising strength and reliability.

Design Advantages

Triple-Path Load Segregation
Each row of rollers handles a specific load: axial, radial, or moment. This optimized load distribution allows for safe operation under extreme mechanical stress.

Large Contact Areas
Rollers offer line contact instead of point contact like ball bearings, which reduces stress concentration and increases wear resistance.

High Stiffness and Stability
The three-row structure significantly boosts system stiffness, minimizing deflection even under high load or dynamic conditions.

Wide Diameter Range
Due to their robust structure, Three-Row Roller Bearings are available in large diameters, often exceeding 10 meters, to support massive machines.

Gear and Non-Gear Variants
Options include external gear, internal gear, or no gear, supporting various torque transmission needs.

Where Are They Used?

Bucket Wheel Excavators: Massive radial and axial loads in continuous material removal.

Ship Cranes and Offshore Platforms: Extreme moment and vibration resistance in marine conditions.

Radar Antennas and Large Turntables: Precise yet heavy-duty rotation under dynamic loads.

Steel Mills and Rotary Kilns: High-temperature, continuous-duty installations.

Tunnel Boring Machines: Demanding torque and load demands in harsh underground environments.

LDB’s Three-Row Roller Slewing Bearings

LDB Bearing, a globally recognized manufacturer, offers a wide selection of Three-Row Roller Slewing Bearings engineered for critical tasks. Each bearing is manufactured in LDB’s ISO-certified facilities using high-strength alloy steel (42CrMo or 50Mn) and roller elements made of GCr15 precision steel.

LDB Features:

Outer Diameter Range: 1000 mm to over 10,000 mm

Load Rating: Over 10 million Nm tilting moment capacity in custom models

Gear Treatment: Induction hardening and CNC gear cutting for high torque transfer

Sealing: Multi-lip seals for water, dust, and chemical protection

Lubrication: Multi-point grease channels with optional auto-lube systems

LDB also offers custom tooth profiles, bolt hole arrangements, and anti-corrosion coatings to meet industry-specific requirements.

Price, Supplier, and Manufacturer Insights

As a premier supplier and manufacturer, LDB provides comprehensive solutions for industries that rely on ultra-heavy-duty slewing systems.

Pricing Factors Include:

Outer diameter and number of rollers

Gear design and torque requirements

Operational environment (e.g., marine, underground)

Custom sealing, mounting, and lubrication systems

Typical Price Range: USD $5000 to $50,000+ depending on dimensions and load capacity.

All price inquiries are handled directly by LDB’s engineering team via www.ldb-bearing.com, where clients can submit 3D CAD files, request test reports, or consult on long-term bulk procurement.

Why Heavy Machinery OEMs Choose LDB

Over 20 years of field-proven design experience

Gear shaping accuracy to DIN 3960/61 standards

Heat-treated raceways for high-cycle fatigue resistance

Application-specific simulation and bearing life prediction

After-sales support with on-site service and global logistics

LDB’s three-row roller slewing bearings have been successfully deployed in over 30 countries, powering the world’s largest cranes, transporters, and energy systems.

Conclusion

When failure is not an option and load conditions are extreme, Three-Row Roller Slewing Bearings are the solution. With LDB as your supplier, you gain access to world-class engineering, manufacturing precision, and tailored support for the most demanding scenarios. Let your machines carry more—with confidence.

Three-Row Roller Slewing Bearings: The Ultimate Load-Bearing Powerhouse

What is a Three-Row Roller Slewing Bearing?

A Three-Row Roller Slewing Bearing is a high-capacity rotational bearing system that features three separate rows of rollers—each row designed to carry different types of load. Unlike single or double-row ball bearings, this design separates axial, radial, and tilting moment loads across three distinct paths, dramatically increasing the load-bearing capacity, stiffness, and operational safety.

These bearings are the largest and most robust slewing rings available in the industry and are widely used in heavy-duty applications that demand uncompromising strength and reliability.

Design Advantages

Triple-Path Load Segregation
Each row of rollers handles a specific load: axial, radial, or moment. This optimized load distribution allows for safe operation under extreme mechanical stress.

Large Contact Areas
Rollers offer line contact instead of point contact like ball bearings, which reduces stress concentration and increases wear resistance.

High Stiffness and Stability
The three-row structure significantly boosts system stiffness, minimizing deflection even under high load or dynamic conditions.

Wide Diameter Range
Due to their robust structure, Three-Row Roller Bearings are available in large diameters, often exceeding 10 meters, to support massive machines.

Gear and Non-Gear Variants
Options include external gear, internal gear, or no gear, supporting various torque transmission needs.

Where Are They Used?

Bucket Wheel Excavators: Massive radial and axial loads in continuous material removal.

Ship Cranes and Offshore Platforms: Extreme moment and vibration resistance in marine conditions.

Radar Antennas and Large Turntables: Precise yet heavy-duty rotation under dynamic loads.

Steel Mills and Rotary Kilns: High-temperature, continuous-duty installations.

Tunnel Boring Machines: Demanding torque and load demands in harsh underground environments.

LDB’s Three-Row Roller Slewing Bearings

LDB Bearing, a globally recognized manufacturer, offers a wide selection of Three-Row Roller Slewing Bearings engineered for critical tasks. Each bearing is manufactured in LDB’s ISO-certified facilities using high-strength alloy steel (42CrMo or 50Mn) and roller elements made of GCr15 precision steel.

LDB Features:

Outer Diameter Range: 1000 mm to over 10,000 mm

Load Rating: Over 10 million Nm tilting moment capacity in custom models

Gear Treatment: Induction hardening and CNC gear cutting for high torque transfer

Sealing: Multi-lip seals for water, dust, and chemical protection

Lubrication: Multi-point grease channels with optional auto-lube systems

LDB also offers custom tooth profiles, bolt hole arrangements, and anti-corrosion coatings to meet industry-specific requirements.

Price, Supplier, and Manufacturer Insights

As a premier supplier and manufacturer, LDB provides comprehensive solutions for industries that rely on ultra-heavy-duty slewing systems.

Pricing Factors Include:

Outer diameter and number of rollers

Gear design and torque requirements

Operational environment (e.g., marine, underground)

Custom sealing, mounting, and lubrication systems

Typical Price Range: USD $5000 to $50,000+ depending on dimensions and load capacity.

All price inquiries are handled directly by LDB’s engineering team via www.ldb-bearing.com, where clients can submit 3D CAD files, request test reports, or consult on long-term bulk procurement.

Why Heavy Machinery OEMs Choose LDB

Over 20 years of field-proven design experience

Gear shaping accuracy to DIN 3960/61 standards

Heat-treated raceways for high-cycle fatigue resistance

Application-specific simulation and bearing life prediction

After-sales support with on-site service and global logistics

LDB’s three-row roller slewing bearings have been successfully deployed in over 30 countries, powering the world’s largest cranes, transporters, and energy systems.

Conclusion

When failure is not an option and load conditions are extreme, Three-Row Roller Slewing Bearings are the solution. With LDB as your supplier, you gain access to world-class engineering, manufacturing precision, and tailored support for the most demanding scenarios. Let your machines carry more—with confidence.