What is excavator slew bearing?
What is Excavator Slew Bearing?
An excavator slew 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. Slew bearings are engineered to handle simultaneous axial, radial, and moment loads. In excavators, these bearings are crucial as they enable the cab and the attached boom to rotate smoothly around the undercarriage without any hindrance.
Types of Excavators Slew Bearing
The types of slew bearings used in excavators can vary based on the design and requirements of the machinery. Common types include:
Single-row Four-point Contact Ball Bearing – This is the most common type, capable of handling axial and radial forces in both directions. It features a single row of balls with a gothic arch raceway design which allows for four points of contact with the balls, accommodating tilting moments efficiently.
Double-row Ball Slew Bearing – This design offers higher load capacities than single-row types by having two rows of rolling elements. It handles larger axial and radial loads and can support larger tilting moments.
Crossed Roller Slew Bearing – In this type, rollers are arranged in a crossed pattern, which provides higher stiffness and can carry higher loads than ball bearings. This type is ideal for applications requiring high precision and rigidity.
Three-row Roller Slew Bearing – This design incorporates three rows of rollers, which bear different loads separately, thus allowing for maximum load capacity in all directions. It’s suitable for heavy-duty applications where high load capacity is crucial.
Function of Excavator Slew Bearing
The primary function of an excavator slew bearing is to facilitate the rotation of the upper structure (cab, engine, boom, etc.) independently of the undercarriage. This bearing is critical for the following functions:
Rotation Capability: Allows 360-degree rotation of the upper part of the excavator, which is essential for tasks like digging and dumping without moving the base.
Load Handling: Supports axial, radial, and moment loads during the operation of the excavator.
Precision Movement: Ensures smooth and precise movement, which is crucial for operation efficiency and safety.
Applications of Slew Bearing
Slew bearings are not only used in excavators but also find applications in several other fields:
Cranes and Lifts: For rotation mechanisms in tower cranes, mobile cranes, and boom lifts.
Wind Turbines: In the yaw and pitch mechanisms that adjust the blades and orientation of the turbine.
Medical Equipment: In devices like CT scanners and medical chairs where precise and smooth rotation is required.
Robotic Arms and Manufacturing Equipment: For joints that require rotational movement.
How to Select Slew Bearing for Excavator?
Selecting the right slew bearing for an excavator involves several considerations:
Load Capacity: Determine the axial, radial, and moment loads the bearing needs to support.
Size and Space Constraints: Consider the physical dimensions available in the excavator design.
Precision and Rigidity Requirements: Depending on the application’s precision needs, choose between ball and roller bearings.
Environment and Service Life: Assess the environmental conditions (dust, temperature, moisture) and desired service life, which influence material and sealing choices.
Manufacturer and Technical Support: Opt for reliable manufacturers and ensure availability of technical support and replacement parts.
Selecting the appropriate slew bearing is crucial for ensuring the reliability, efficiency, and longevity of the excavator. Proper maintenance and regular inspection are also vital to maximize the lifespan and performance of slew bearings.
About LDB Bearing
LDB Bearing is a professional slewing bearing, slewing ring, slew drive and customize slew bearing manufacturer in China. If you are looking for excavator slew bearings, feel free to contact us.
