How to select slewing bearing

A slewing bearing is a specialized type of bearing that allows for rotational or slewing movement, typically used in heavy machinery. It consists of an inner ring and an outer ring, with rolling elements (like balls or rollers) between them. Unlike traditional bearings, slewing bearings are designed to handle both axial (up-and-down), radial (side-to-side), and moment (tilting) loads simultaneously.

Selecting a slewing bearing requires careful consideration of the application, load requirements, and environmental factors. Here’s a step-by-step guide to help you choose the right slewing bearing:

Slewing Bearing Selection

1. Load Type and Magnitude

Radial Load: The force perpendicular to the axis of rotation.

Axial Load: The force parallel to the axis of rotation.

Moment Load: The force that causes the bearing to tilt or rotate about an axis.

Tip: Identify the magnitude of these loads and choose a bearing with appropriate load capacities. Most manufacturers provide load capacity charts for slewing bearings.

2. Operating Conditions

Speed: Consider the rotational speed and any speed variations.

Temperature: Check if the slewing bearing can withstand extreme temperature conditions.

Environment: Dust, moisture, and corrosive environments may require bearings with special seals or coatings.

3. Precision Requirements

Applications such as robotics or medical equipment require high-precision slewing bearings. For heavy machinery, moderate precision is usually sufficient.

4. Mounting and Installation

Ensure the bearing fits within the space available in the equipment.

Some bearings have internal or external gear teeth, while others are toothless—choose the right one depending on the drive system.

5. Bearing Type

There are different types of slewing bearings, including:

Single-row ball slewing bearing: Suitable for light to moderate axial and radial loads.

Double-row ball slewing bearing: Designed for higher radial and axial loads.

Crossed roller slewing bearing: Suitable for applications with high precision and moment loads.

Three-row roller bearing: Offers the highest load-carrying capacity for axial, radial, and moment loads.

6. Material and Durability

Most slewing bearings are made of high-strength steel, but some applications may require stainless steel or other materials for corrosion resistance.

Ensure that the bearing is treated for wear resistance if it will be subjected to heavy or constant loads.

7. Maintenance Requirements

Some slewing bearings are maintenance-free, while others require regular lubrication and inspection.

Check for the type of lubrication used (grease or oil) and whether the bearing has grease fittings or sealed options.

8. Manufacturer Recommendations

Always follow manufacturer recommendations and standards (e.g., ISO or DIN) for selecting and installing slewing bearings.

By carefully evaluating these factors, you can choose a slewing bearing that fits your specific requirements.