What is slew bearing?
What is a Slew Ring Bearing?
A slew ring bearing, also known as a slewing ring or turntable bearing, is a rotational rolling-element bearing that typically supports a heavy but slow-turning or slow-oscillating load, often a horizontal platform such as a conventional crane, a swing yarder, or the wind-facing platform of a horizontal-axis windmill. It consists of an inner ring and an outer ring, one of which usually incorporates a gear. Together with attachment holes in both rings, they enable an optimized power transmission with a simple and quick connection between adjacent machine components.
Types of Slew Ring Bearings
Slew ring bearings are categorized mainly based on their design and the demands of the application:
Single-row Four-point Contact Ball Bearing – This type is the most common, characterized by a single row of balls with the contact angle that can support axial, radial, and moment loads.
Double-row Ball Bearing – Offers higher load capacity than a single-row, using two rows of balls.
Crossed Roller Bearing – Rollers are arranged at right angles to each other at intervals between inner and outer rings. This design offers high stability and accuracy, suitable for high axial and radial loads.
Three-row Roller Bearing – This type combines three rows of rollers to bear different loads separately, facilitating higher load capacity and rigidity.
Ball and Roller Combination Bearing – These bearings combine both rollers and balls in different rows to optimize load capacity and reduce material costs.
Features of Slew Ring Bearings
High Load Capacity: Designed to handle simultaneously acting radial, axial, and moment loads.
Compactness: They are relatively thin in section and are often made in diameters of a meter or more; thus, they save space compared to conventional bearings.
Rotation Accuracy: Provides precise rotation and positioning.
Ease of Mounting: Their design simplifies the structure of the installation equipment.
Integrated Gearing: Many slew bearings have internal or external gears, facilitating the integration into a system.
Applications of Slew Ring Bearings
Slew bearings are used in a variety of applications including:
Construction machinery like cranes and excavators.
Wind turbines.
Medical equipment, particularly in rotating tables and scanners.
Military applications, such as in radar and missile launchers.
Industrial turntables and manipulators.
Robotics and automation systems.
Price of Slew Ring Bearings
The price of slew ring bearings can vary widely depending on the size, type, material, and specific manufacturer requirements. Small, standard slew bearings might start around a few hundred US dollars, while large, custom-engineered bearings can cost several thousand or even tens of thousands of dollars.
How to Select Slew Ring Bearings?
Selecting the appropriate slew ring bearing involves several considerations:
Load Type and Magnitude: Determine the axial, radial, and moment loads the bearing will need to support.
Precision Requirements: Consider the required precision and rotational speed.
Environmental Conditions: Assess the operating environment, including temperature extremes and exposure to contaminants or corrosive elements.
Size and Space Constraints: Factor in the physical space available for the bearing.
Gear Requirements: Decide if internal or external gearing is necessary for your application.
Material and Coatings: Choose materials and coatings based on environmental and load conditions to enhance durability and performance.
Lifecycle and Maintenance: Consider the expected life and maintenance requirements, including lubrication and inspection intervals.
By understanding these factors, engineers can select the most appropriate slew ring bearing for their specific application, balancing performance, longevity, and cost.
LDB Bearing is a professional slewing bearing manufactuer offers high-quality, custom-tailored slew bearings, slewing drives and gears for your project.
