How to select slewing bearings

Selecting the appropriate slewing bearing involves several factors to ensure it meets the application's requirements for load capacity, operational conditions, and longevity. Below is a systematic guide for selecting slewing bearings.

Slewing bearing selection

1. Understand the Application Requirements

A. Load Conditions

Axial Load: Force acting perpendicular to the bearing's axis.

Radial Load: Force acting along the bearing's axis.

Moment Load: Torque or tilting forces acting on the bearing.

Consider whether the load is constant, variable, or shock-inducing.

B. Operational Parameters

Rotational Speed: Maximum and average speed the bearing must handle.

Duty Cycle: Frequency and duration of operation (e.g., continuous, intermittent).

Precision: Required accuracy in positioning or rotation.

C. Environmental Conditions

Temperature: Minimum and maximum operating temperatures.

Contaminants: Dust, moisture, or corrosive environments that may affect the bearing.

Lubrication: Compatibility with the lubrication system (grease, oil).

D. Mounting and Space Constraints

Dimensions: Inner and outer diameter, height, and weight limits.

Mounting: Bolt hole patterns and flange compatibility.

2. Determine the Bearing Type

Slewing bearings come in various types, each suited to specific applications:

Single-row Ball Bearings:

Suitable for light to moderate axial, radial, and moment loads.

Common in cranes and light-duty turntables.

Double-row Ball Bearings:

Better for higher axial and radial loads.

Used in equipment requiring higher rigidity and load distribution.

Single-row Crossed Roller Bearings:

High precision and load capacity, especially for moment loads.

Ideal for robotics and high-accuracy positioning systems.

Triple-row Roller Bearings:

Best for heavy axial, radial, and moment loads.

Used in heavy machinery like excavators and shipyard cranes.

Ball-Roller Combination Bearings:

Handle a mix of light radial and heavy axial loads.

Used in applications with complex load requirements.

3. Perform Load and Capacity Calculations

Use the manufacturer's load ratings to compare the dynamic and static capacity with application requirements.

Calculate the equivalent load using the formula provided by the bearing supplier, considering:

Load direction and magnitude.

Safety factors for unexpected loads or conditions.

4. Assess Durability and Longevity

L10 Life Expectancy:

Calculate the bearing's expected operational lifespan using industry-standard formulas.

Material Selection:

Choose materials based on load, wear resistance, and environmental exposure (e.g., high-strength steel for heavy loads or corrosion-resistant alloys for marine environments).

5. Check Lubrication and Sealing

Select bearings with adequate lubrication ports and sealing systems to protect against contamination.

Match the lubrication system (grease or oil) to the application's operating conditions.

6. Review Assembly and Maintenance Requirements

Opt for pre-assembled bearings for ease of installation if alignment is critical.

Consider designs with minimal maintenance requirements if the bearing is hard to access.

7. Evaluate Manufacturer and Standards

Quality Assurance:

Select bearings that meet international standards (ISO, DIN, ANSI).

Manufacturer Reputation:

Choose reputable manufacturers with a history of quality and reliability.

8. Final Selection

Obtain Specifications:

Compare catalogs or consult with manufacturers for detailed specifications.

Simulation and Testing:

Use simulation tools to verify performance under operating conditions if possible.

Prototype Testing:

Test a prototype under real-world conditions before full deployment.

Applications of Slewing Bearings

Construction Equipment: Cranes, excavators, concrete pumps.

Industrial Machinery: Turntables, welding tables, material handlers.

Renewable Energy: Wind turbines, solar tracking systems.

Transportation: Railway bogies, shipyard loaders.

By following these steps, you can ensure that the slewing bearing selected meets the performance, durability, and reliability needs of your application.