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The double-row ball slewing bearing transmits the load of the inner and outer rings through two rows of steel balls. Due to the two rows of rolling elements, it can more effectively distribute the axial, radial and overturning moments, thereby bearing a larger composite load than a single-row bearing. The presence of two rows of steel balls also enhances the overall stiffness of the bearing.
Good seals can effectively prevent dust, impurities and moisture from entering the bearing while retaining grease and extending the bearing life.
The double-row ball slewing bearing consists of an inner ring and an outer ring. The cage separates the two rows of steel balls and guides them to be evenly distributed, preventing the steel balls from contacting each other, reducing friction and increasing the bearing life.
Usually there are two sets of raceways, one for each row of balls. The raceway form can be a Gothic arch with four-point contact, or other forms according to specific needs.
This is its most important structural feature. It has two rows of steel balls with independent or shared raceways. These steel balls are usually of the same or different diameters and are arranged between the inner and outer rings.
Greater load capacity and better load distribution help reduce raceway and rolling element fatigue, thereby extending bearing life.
Due to its solid structure and excellent load-bearing capacity, double-row ball slewing bearings are particularly suitable for use in harsh working environments and where loads change frequently.
The contact angles of the two rows of raceways can be optimized for loads in different directions (axial force, radial force, overturning moment). For example, the arc angles of the upper and lower raceways are usually designed to be 90° to withstand large axial moments and overturning moments to the greatest extent.
Due to its strong load-bearing capacity, the double-row ball slewing bearing has a higher safety factor when carrying large loads, reducing the risk of failure.
The design of two rows of steel balls greatly increases the overall rigidity of the bearing, effectively resists deformation, and maintains the stability and precision of the mechanical system under heavy loads.
This is the most prominent advantage of the double-row ball slewing bearing. Compared with a single-row four-point contact ball slewing bearing of the same size, the double-row design can significantly increase the load-bearing capacity of axial, radial and especially overturning moments. This makes it very suitable for bearing heavy loads and harsh working conditions.
Double-row ball slewing bearings are large-diameter rotational bearings designed with two rows of steel balls to support combined axial, radial, and tilting moment loads simultaneously. Compared with single-row slewing bearings, double-row designs provide higher load-carrying capacity and improved operational stability for heavy-duty applications.
These bearings are widely used in cranes, excavators, aerial work platforms, port machinery, and wind energy equipment.
Double-row ball slewing bearings provide several important advantages:
Higher axial load capacity
Better tilting moment resistance
Improved rotational stability
Longer service life under heavy-duty conditions
Lower vibration during operation
Better suitability for large equipment
Many equipment manufacturers choose double-row structures when the machine must operate under continuously changing loads or harsh working environments.
Manufacturers use double-row ball slewing bearings in many heavy industrial sectors, including:
Construction machinery
Tower cranes
Mobile cranes
Port handling equipment
Mining machinery
Wind turbines
Radar systems
Rotary drilling rigs
Offshore equipment
Industrial turntables
These applications require stable rotation, high rigidity, and reliable load distribution.
The primary difference lies in load capacity and structural design.
Single-row slewing bearings generally suit lighter or medium-duty applications, while double-row ball slewing bearings are designed for heavier axial loads and larger overturning moments.
The double-row structure distributes loads more evenly across two ball rows, which improves bearing rigidity and operational reliability.
Most double-row ball slewing bearings use high-quality alloy bearing steel or forged ring materials to ensure strength and durability.
Depending on the application environment, manufacturers may also provide:
Corrosion-resistant coatings
Stainless steel components
Induction-hardened raceways
Customized sealing systems
High-performance lubrication solutions
Material selection directly affects bearing lifespan and operating reliability.
Users should evaluate several technical factors before selecting a slewing bearing:
Axial load requirements
Radial load conditions
Tilting moment values
Rotational speed
Mounting dimensions
Working temperature
Environmental conditions
Gear requirements
Professional bearing manufacturers often assist customers with load calculations and model selection to ensure optimal performance.
Lubrication intervals depend on operating conditions, rotational frequency, and environmental exposure.
Heavy-duty or high-temperature applications may require more frequent lubrication. In most industrial environments, operators should perform regular grease replenishment according to the manufacturer’s maintenance schedule.
Proper lubrication reduces friction, minimizes wear, and extends bearing life.
Yes. Many manufacturers provide customized solutions based on customer requirements.
Common customization options include:
Internal or external gear designs
Non-gear configurations
Special mounting hole patterns
Customized dimensions
Anti-corrosion treatments
High-temperature grease
Sealing upgrades
Precision machining tolerances
Customized slewing bearings help improve equipment integration and operational efficiency.
The mounting surface directly affects load distribution and rotational accuracy.
Uneven or improperly machined mounting structures may cause localized stress concentration, abnormal vibration, and premature raceway wear.
Manufacturers generally recommend strict flatness and rigidity requirements during installation.
Double-row ball slewing bearings are primarily designed for low-speed, heavy-load rotational applications rather than high-speed systems.
For higher rotational speeds, engineers must carefully evaluate lubrication, heat generation, and cage design to ensure stable operation.
