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What is Double Row Ball Slew Bearing?

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It is a two-row ball structure and is widely used in mechanical equipment requiring high-precision rotation and heavy-load capacity. A double row ball slew bearing is a large rotational bearing designed to withstand combined axial loads, radial loads, and overturning moments.   

What is the feature of Double Row Ball Slew Bearing?

The double-ball slewing bearing integrates innovative design and practical functions. It has a compact structure and occupies a small space, enabling efficient operation within a limited space and being adaptable to a variety of precision equipment.The unique double-ball structure greatly enhances its load-bearing capacity, allowing it to withstand axial and radial loads as well as overturning moments simultaneously, and making it suitable for complex working conditions.The high-precision manufacturing process ensures the slewing accuracy, enabling smooth operation, reducing vibration and noise, and extending the service life of the equipment.It is easy to install and has a low maintenance cost, which can effectively reduce the downtime and improve production efficiency. Widely used in fields such as construction machinery and automated equipment, it is a key component that promotes the efficient development of the industry.

Basic Structure of Double Row Ball Slew Bearing  

Double Row Ball Arrangement:Two independent rows of steel balls (rolling elements) are arranged in concentric raceways, allowing simultaneous distribution of loads in different directions. 

Inner and Outer Rings: Precision-machined raceways on the fixed outer ring and rotating inner ring (or vice versa), often integrated with gear teeth to drive rotation. 

Seals and Lubrication: Equipped with sealing rings to prevent contamination and lubrication ports for regular greasing to extend service life. 

Core Functions 

Multi-Directional Load Capacity: 

Axial Loads: Forces along the rotation axis (e.g., vertical pressure from cranes). 

Radial Loads: Forces perpendicular to the rotation axis (e.g., lateral forces from robotic arms). 

Overturning Moments: Torque caused by eccentric loads (e.g., twisting forces from wind turbine blades). 

High Rigidity Rotation 

The double row ball structure distributes stress, minimizes deformation, and ensures smooth rotation. 

Advantages and Disadvantages of Double Row Ball Slew Bearings 

Advantages: 

High Load Capacity: Multi-directional load support: Suitable for complex stress scenarios (e.g., wind turbines, cranes). Double row design: Distributes loads across two rows, improving capacity by 30%~50% compared to single-row bearings and reducing localized stress. 

Smooth Operation with Low Friction: Small ball contact area reduces friction, enabling precise control (e.g., medical devices, radar antennas). Low heat generation extends lubrication intervals and bearing life. 

Compact and Integrated Design: Integration of gears (internal/external teeth), seals, and lubrication ports saves space. Ideal for applications with strict space constraints (e.g., industrial robot joints). 

Versatility

Material options (standard steel, stainless steel, anti-corrosion coatings) adapt to diverse environments (humid, corrosive). Suitable for low-speed heavy-load and medium-speed rotation scenarios. 

Disadvantages 

Limited Adaptability to Extreme Overturning Moments: Prone to ball slippage under high overturning moments compared to **crossed roller bearings, leading to localized wear. Extreme torque scenarios (e.g., heavy-duty machine tool turntables) require crossed or triple-row roller bearings. 

High Installation Precision Requirements: 

Base flatness tolerance must be ≤0.1 mm/m; deviations cause uneven raceway loading and accelerated fatigue failure. Demands experienced installers; improper installation risks early failure. 

Higher Maintenance Costs: 

Regular lubrication (every 500 operating hours) and seal replacement are critical; contamination shortens lifespan. Replacement in heavy machinery (e.g., wind turbines) requires costly disassembly and crane operations. 

Cost-Performance Trade-offs: More expensive than single-row ball bearings but weaker in load capacity than crossed roller bearings. Oversized models (e.g., diameter >5 meters) face manufacturing challenges and long lead times.

Application examples of this kind of bearings

In a wind turbine, the double-row ball slewing bearing is installed between the top of the tower and the nacelle:Axial force: The vertical pressure generated by the self-weight of the blades and the nacelle.Radial force: The lateral thrust caused by the wind shear force.Overturning moment: The torque generated by the aerodynamic imbalance during the rotation of the blades.

The load is dispersed through the two rows of balls, ensuring that the nacelle can yaw stably to align with the wind direction even under strong winds.

Factors Influencing the Price of Double Row Ball Slew Bearings 

The price of double row ball slew bearings is affected by multiple factors, including raw materials, manufacturing processes, and market dynamics. 

Material Costs: 

Steel Type: 

Standard bearing steel (e.g., GCr15) is cost-effective but corrosion-prone. 

Stainless steel (e.g., 440C) or specialty alloys (e.g., 42CrMo4) cost 30%~50% more but suit harsh environments (e.g., marine applications). 

Heat Treatment

Processes like carburizing and surface hardening improve hardness and wear resistance but add 15%~25% to processing costs. 

Size and Load Capacity: 

Diameter Range: 

Small bearings (diameter <1 meter): ¥10,000–¥50,000. Large bearings (diameter >3 meters, e.g., for wind turbines): ¥500,000–¥2,000,000 due to material and machining complexity. 

Load Rating: 

High-load designs (dynamic load rating >500 kN) require reinforced raceways and balls, increasing costs by 20%~40%. 

Manufacturing Complexity: 

Raceway Machining Accuracy: 

High-precision grinding (Ra ≤0.4 μm) costs 30%~50% more than standard turning (Ra ≤1.6 μm) but extends service life. 

Gear Integration: 

Internal/external gear machining requires specialized equipment; each precision grade improvement (e.g., DIN Class 6) adds 10%~15% to costs. 

Seal Design: 

Multi-lip or labyrinth seals cost 20%~35% more than standard rubber seals but offer superior dust/water resistance. 

Customization Requirements: 

Non-Standard Designs: 

Customized mounting holes or flange interfaces increase design and tooling fees (10%~20% of total cost). 

Special Coatings 

Zinc plating, Dacromet, or PTFE anti-corrosion coatings add 5%~15% to costs but suit chemical or marine environments. 

Market Factors: 

Supply-Demand Dynamics: 

Prices rise 10%~30% during high-demand periods (e.g., 2021 wind power installation surge). 

Regional Cost Differences 

Chinese-made bearings are 30%~50% cheaper than European/American equivalents due to lower labor and material costs. 

Transportation and Installation Costs

Logistics

Oversized bearings (e.g., 5-meter diameter) require special transport, with freight accounting for 5%~10% of total cost. 

Installation Complexity 

High-precision installation (flatness ≤0.1 mm/m) demands professional teams, increasing labor costs by 5%~8%. 

The double-row ball slewing bearing optimizes the load distribution through two rows of balls. It is a key component that balances the load-bearing efficiency and space occupation, and is widely used in heavy-duty rotating equipment that needs to bear complex loads. However, its installation accuracy and maintenance requirements are relatively high, and a comprehensive selection should be made according to the working conditions.

The price of double ball slewing bearing

The price of double ball slewing bearing is influenced by multiple factors. Raw material costs are crucial. Fluctuations in the prices of steel and other materials directly affect the product. The complexity of the manufacturing process, such as high – precision processing and the creation of the unique double ball structure, means that the more complex the process, the higher the cost. Different requirements for load – bearing capacity and precision also lead to price differences. Products with high load – bearing capacity and high precision are more expensive due to the greater investment in technology and quality control. When the supply is in short supply, the price rises, and when the supply exceeds demand, the price falls.

Supplier of Double Ball Slewing Bearings

If you want to purchase bearings, you can get in touch with us. LDB-Bearing Company has advanced bearing manufacturing techniques and ensures strict compliance with national standards. Moreover, our R&D team has continuously received research and development funds, which guarantees that we won’t fall behind our peers. We can provide you with different bearings tailored to various industries. Meanwhile, we have a complete after-sales service system. Once you have any problems, we will reply to you immediately and offer reasonable solutions. If you’d like to know more, please feel free to contact us.

What is high-quality slew bearing?

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A bearing is a core component in mechanical engineering. Its core functions can be summarized as: supporting rotating components, reducing friction, and ensuring the efficient and smooth operation of machinery. Simply put, it is a key part that enables machines to “rotate smoothly”.

What is the feature of slew bearing?

Slewing bearing supports have the following characteristics: They can withstand axial forces, radial forces, and overturning moments simultaneously, and can achieve a relatively smooth 360-degree slewing motion. With a compact structure, they occupy a small space, effectively saving the space of the equipment. They are easy to install and can be easily connected and matched with other components. They have a relatively high precision, which can ensure the accuracy and reliability of the slewing motion. They have a large load-bearing capacity, are suitable for various heavy-duty working conditions, and are widely used in fields such as construction machinery and port machinery.

Classification of slew Bearings

There are many ways to classify slew bearings. Here, based on the working principle, we can divide them into:

Rolling bearings: Their main feature is that rolling elements (such as steel balls, rollers) roll between the inner and outer rings to reduce friction.

Advantages: Low friction, high efficiency, and easy maintenance.Disadvantages: Sensitive to foreign objects and require regular lubrication.

Sliding bearings: They have no rolling elements and rely on a lubricating film for direct sliding (such as bearing bushes).

Advantages: Simple structure, impact-resistant, and suitable for high-speed and heavy-load applications.Disadvantages: High friction and require continuous lubrication.

Application of Slew Bearings

Industrial Field

Machine tools: High-precision bearings are used in the spindles of machine tools to ensure the rotational accuracy during tool cutting, guaranteeing the dimensional accuracy and surface quality of the machined parts.

Motors: The rotor of a motor is supported by bearings, enabling the rotor to rotate smoothly, reducing friction losses, and improving the efficiency and service life of the motor.

Metallurgical equipment: For example, the bearings in steel rolling mills need to withstand huge rolling forces to ensure the stable rotation of the rolls and achieve the rolling of steel.

Transportation Field

Automobiles: Wheel hub bearings support the wheels of automobiles, bearing the weight of the vehicle and various forces during driving. At the same time, they ensure the free rotation of the wheels, which is crucial for the vehicle’s handling and safety.

Trains: Axle box bearings are used between the train axles and bogies, adapting to high-speed driving and heavy-load requirements, and ensuring the stability and reliability of train operation.

Aircraft: The bearings in aircraft engines need to operate under high temperature, high speed, and high load conditions, ensuring the stable rotation of the engine rotor, and are key components for the reliable operation of the engine.

Home Appliance Field

Air conditioners: The bearings in air conditioner compressors ensure the rotation of the compressor crankshaft, enabling the compressor to efficiently compress and transport refrigerant.

Washing machines: The rotation of the inner drum of a washing machine relies on bearings for support. They can bear the weight of clothes and water, ensuring the stable operation of the washing machine at different speeds.

Other Fields

Medical devices: High-precision bearings in devices such as CT scanners and MRI machines ensure the precise rotation and positioning of the scanning components, improving the imaging quality.

Robots: The bearings at the joints of robots enable the joints to rotate flexibly, enabling various complex movements, and play a key role in the motion accuracy and stability of robots.

Wind turbines: The main bearings support the impeller shaft of wind turbines, bearing huge axial and radial loads, ensuring the stable rotation of the impeller under different wind speeds and converting wind energy into electrical energy.

How to maintain the bearing

Application Scenarios and Load Requirements

Load Type: Determine the type of load (radial, axial, or combined load) that the bearing will bear, and select the corresponding bearing type (for example, deep groove ball bearings are suitable for radial loads, and tapered roller bearings are suitable for combined loads).

Load Magnitude: Select the bearing size and load-carrying capacity according to the load intensity (refer to dynamic/static load parameters).

Rotational Speed Requirements: For high-speed applications, choose bearings with low friction (such as angular contact ball bearings or ceramic bearings), and ensure that the rated speed limit is not exceeded.

Adaptability to the Working Environment

Temperature:

High-temperature environment: Choose high-temperature-resistant materials (such as stainless steel, ceramic bearings) or adopt cooling measures.

Low-temperature environment: Use low-temperature grease or special alloy bearings.

Corrosion: In humid or chemically corrosive environments, give priority to stainless steel, coated bearings, or sealed bearings.

Dust/Pollution: Select bearings with rubber seals (such as 2RS type) or dust covers (such as ZZ type), or install protective covers externally.

Bearing Types and Structures

Rolling bearings (such as ball bearings, roller bearings):

Advantages: Low friction, high efficiency, and easy maintenance.

Applicable scenarios: Medium to high speed, low impact load (such as motors, machine tools).

Sliding bearings (such as bearing bushes, self-lubricating bearings):

Advantages: Impact-resistant, suitable for heavy-load or low-speed applications.

Applicable scenarios: Metallurgical equipment, large machinery.

Materials and Processes

Material Selection:

Ordinary steel: Economical, suitable for general industrial environments.

Stainless steel: Corrosion-resistant, suitable for the food and chemical industries.

Ceramics (such as silicon nitride): High-temperature-resistant, lightweight, suitable for high-speed or extreme environments.

Manufacturing Process: High-precision bearings (such as P4/P5 grade) are used in precision equipment (such as machine tool spindles, medical instruments).

Lubrication Management

Lubrication Methods:

Grease lubrication: Suitable for medium to low speed, maintenance-free scenarios (such as lithium-based grease).Oil lubrication: Suitable for high speed, high temperature, or heavy load (such as ISO VG 32 – 100 mineral oil).Sealing Design: Sealed bearings (such as rubber-sealed) can reduce contamination and extend the lubrication cycle.

The Price of Bearings

The price of bearings is affected by many factors. For example, different brands use different processes, which will affect the price. Different materials also have different applications, which also affect the price. In addition, market demand is one of the main factors. LDB Company provides many different types and uses of bearings. If you want to know more, you can contact us.

Slew Bearing manufacturer

LDB was established in 1999. It is a company that focuses on scientific and technological innovation, with more than 20 utility model patents, and has won many honorary titles such as Henan Provincial Science and Technology-based Small and Medium-sized Enterprise. We are committed to the design, development, manufacturing, and sales of slewing drives and slewing bearings. If you want to inquire or purchase bearings, you can consult us.

Comprehensive guide on Slewing Ring Bearing

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What is a Slewing Ring Bearing?

A slewing ring bearing (also known as a turntable bearing or slew bearing) is a type of large bearing designed to accommodate axial, radial, and moment loads simultaneously. It typically consists of an inner ring, outer ring, rolling elements (such as balls or rollers), and a raceway. These bearings are used in applications where rotational movement is required, often with heavy loads and low to moderate speeds.

Types of Slewing Ring Bearings

Slewing ring bearings can be classified based on several factors, including the type of rolling element and the arrangement of the bearing components:

  1. Four-point contact bearings: These have four contact points between the balls and the raceways, allowing them to carry both axial and radial loads along with tilting moment loads. They are commonly used in applications where the load is evenly distributed.
  2. Crossed roller bearings: In these, the rollers are arranged in a criss-cross pattern, offering high load capacity and rigidity. They can handle high axial and radial loads with better precision, often used in precise rotating mechanisms.
  3. Ball type slewing bearings: These use balls as rolling elements and are suitable for applications with lighter loads and moderate rotational speeds.
  4. Roller type slewing bearings: These use cylindrical or tapered rollers for heavier-duty applications, providing a higher load capacity than ball type bearings.
  5. Triple-row bearings: These have three rows of rolling elements—balls or rollers—allowing them to handle higher loads and improve stiffness. They are often used in large machinery like cranes and excavators.

Features of Slewing Ring Bearings

  • Load handling: Slewing ring bearings are capable of supporting axial, radial, and moment loads simultaneously, making them ideal for machines that require rotational movement under heavy loads.
  • Precision: Many slewing ring bearings are designed with high precision to maintain accurate and smooth rotational movement.
  • Compact design: The compact nature of slewing ring bearings makes them suitable for applications with space constraints.
  • Durability: They are typically made from high-strength steel or other durable materials to withstand harsh operating conditions.
  • Versatility: Slewing ring bearings can be custom-made to fit specific applications, allowing for flexible design options.
  • Sealing: Many slewing bearings come with integrated seals to prevent contamination and reduce maintenance needs.

Applications of Slewing Ring Bearings

  • Crane systems: Used in tower cranes, mobile cranes, and crawler cranes to allow rotation and movement of heavy loads.
  • Wind turbines: For the yaw bearing in wind turbine systems, allowing the turbine to rotate and face the wind.
  • Construction equipment: Excavators, loaders, and other heavy machinery use slewing ring bearings for rotational movement.
  • Marine applications: Used in the turntables of radar, communication, and other systems aboard ships.
  • Solar tracking systems: In solar panels, slewing rings help with tracking the sun’s position to maximize energy capture.
  • Heavy industrial machinery: In machines like rotary tables and turntables for precise rotation under load.

How to Select Slewing Ring Bearings?

Selecting the right slewing ring bearing depends on several factors:

  1. Load requirements: Determine the axial, radial, and moment loads the bearing must support. The type and size of the bearing should be chosen based on the load capacity needed.
  2. Rotational speed: Consider the speed at which the bearing will rotate. Higher speeds might require bearings with lower friction and specialized materials.
  3. Operating environment: If the bearing will operate in harsh conditions (extreme temperatures, dust, moisture), ensure it has appropriate seals and coatings to withstand these conditions.
  4. Precision and rigidity: For applications requiring high precision and low deflection, like robotics or industrial machinery, choose a bearing with high rigidity, such as crossed roller bearings.
  5. Space limitations: If space is a concern, a smaller, lighter slewing ring bearing may be necessary. Ensure that the bearing fits within the required dimensions without compromising performance.
  6. Material selection: Choose the material based on the operating environment (corrosion resistance, high strength, etc.). Common materials include high-strength steel, stainless steel, and sometimes ceramic components for special applications.
  7. Maintenance and longevity: Consider the maintenance needs of the bearing, including lubrication intervals, ease of replacement, and expected operational lifespan.

By carefully evaluating these factors, you can select the slewing ring bearing best suited to your application, ensuring optimal performance and longevity.

Supplier of Slewing Ring Bearing

LDB Bearing is a professional slewing ring bearing manufacturer has rich experience in supplying high quality and precision slewing bearing for large projects. If you are looking for slewing ring bearing for your projects, feel free to contact us.