Slewing Bearing

Slewing bearings, also called slew ring bearings or slew bearings, are large-diameter rotary bearings built to carry axial loads, radial loads, and tilting moment loads at the same time. This combined load capacity is what separates a slewing bearing from a standard bearing, and it is why they are used as the main point of rotation in equipment that needs to turn under load rather than spin freely.

A slewing ring bearing consists of an inner ring and an outer ring with rolling elements between them. Some designs add gear teeth on the inner or outer ring so the assembly can be driven directly by a motor or pinion. The rolling elements can be balls, cylindrical rollers, or a mix of both, depending on the load and precision requirements of the application.

LYDL manufactures slewing bearings for robotics, automation equipment, rotary tables, and precision machinery. Our slewing ring bearings are available in cross-roller, four-point-contact ball, and triple-row roller configurations, each suited to a different combination of load, speed, and precision.

Types of Slewing Bearings

LYDL Bearings manufactures three main types of slewing bearings, each suited to a different load and precision profile. The cross roller slewing bearing uses cylindrical rollers in a crossed arrangement on a single raceway, giving high rigidity and low clearance for robotic joints, rotary tables, and machine tool axes. The four-point contact ball slewing bearing uses a single row of balls that contact the raceway at four points, offering a compact and cost-effective option for general rotation applications with moderate loads. The triple row roller slewing bearing separates the load path into three rows, typically two axial rows and one radial row, which increases overall load capacity for heavy-duty and large diameter equipment.

How to Choose a Slewing Bearing

Selecting the right slew ring bearing depends on a few factors specific to the application.

• Load type and magnitude. Radial load, axial load, and moment load rarely act alone. Identify which load direction is dominant before choosing a bearing type.
• Precision requirements. Robotics, rotary tables, and measuring equipment need low runout and tight clearance, which points toward cross roller designs.
• Rotation speed. Continuous or high-speed rotation favors ball type slewing bearings due to lower friction. Slow, heavy-duty rotation favors roller type designs.
• Diameter and available space. Larger diameters distribute load over a longer raceway but require more mounting space. Compact equipment often calls for cross roller or four-point contact designs.
• Gearing. Confirm whether the application needs internal gear, external gear, or a gearless slewing ring, since this affects how the bearing is driven.

Slewing Bearing Applications

Slewing bearings are used wherever equipment needs controlled rotation under load rather than free spinning motion.

• Industrial robotics. Robotic arm joints use slewing bearings, often cross roller types, for accurate, repeatable rotation at each axis.
• CNC and machine tools. Rotary tables and indexing units rely on slewing bearings to hold position accurately while carrying workpiece loads.
• Automation equipment. Turntables, positioners, and pick and place systems use slewing rings as the central rotation component.
• Measuring and inspection systems. Precision measuring equipment uses slewing bearings where angular accuracy directly affects measurement results.
• Medical and semiconductor equipment. Applications that need clean, precise, low backlash rotation often specify cross roller slewing bearings.

Slewing Bearing Comparison

Your Question, Answered Here

What is a slewing bearing?

A slewing bearing is a large diameter rotary bearing that carries axial, radial, and moment loads at the same time, allowing controlled rotation under combined loading.

What is the difference between a slewing bearing and a slew ring?

There is no difference. Slewing bearing, slew ring, slew bearing, and slewing ring bearing all refer to the same type of component.

What is the difference between a cross roller and a four point contact slewing bearing?

A cross roller slewing bearing uses crossed cylindrical rollers for higher rigidity and precision, while a four point contact ball slewing bearing uses a single row of balls and suits lighter, more general rotation applications.

Can slewing bearings be customized?

Yes. Bore size, gear configuration, sealing, and mounting hole pattern can typically be customized to match the application.

Which industries use slewing bearings most?

Robotics, CNC machinery, automation equipment, construction machinery, and wind turbines are the largest users of slewing bearings.