How Does a Slewing Ring Work?
24th August 2020


Slewing Rings

A slewing ring, also known as a slewing bearing, is made up of an inner ring and an outer ring. One of which will generally incorporate a gear whilst both elements include attachment holes, enabling for optimised power transmission with a simple and fast connection between adjacent components.

These units are designed to transmit axial, radial, and tilting moment loads in one assembly, greatly reducing space, weight and the high costs of investing in other rotational designs. The bearing raceways, in combination with the rolling elements and cages or spacers, can accommodate loads acting individually or in combination, and in any direction. Slewing rings vary considerably depending on size and the bolt hole pattern, yet they can be constructed with:

  • An internal or external gear
  • Ball or crossed roller bearing design
  • Single or double rows
  • Lubrication holes

That said, the success of a slewing ring correlates to how the system is driven, but below are some of the most common types:


Single row

With a row of steel balls as the body, the balls are separated by an isolation block. The inner and outer rings are critical and the steel balls are loaded by plugging holes, meaning the steel ball is in contact with the rolling path at four points bearing axial force, radial force and tipping movement all at the same time.


Double row

Much like the single row contact ball slewing bearing but with two rows of steel balls as the rolling body. All of the balls are the same size, whilst the inner and outer rings are integral once more.


Triple row

Composed of three rings, the upper and lower rows are distributed horizontally to endure the axial force and tipping moment (both ways). The radial force is therefore tolerated by the third row of vertically arranged rollers.


Cross roller

With this design, the rolling bodies are cylindrical rollers and the axes of adjacent rollers are arranged in a 90° cross arrangement. Half of the rollers bear the downward axial force, and half tolerate the upward axial force.


Double exclusion ball

With upper and lower double rows of steel balls, the double exclusion ball bearing features inner and outer rings, isolation blocks and lubricating devices.



There are so many different types of slewing rings to choose from, including externally geared, internally geared and ungeared. Whether you’re looking to improve load carrying, stability or power transmission for your industrial machines, slewing rings can deliver the quality needed to maximise performance.

At Bearing Revolution, we provide the widest range of slewing rings, stocking all of the leading brands including SKF, FAG, INA, RHP/NSK, Torrington, Timken, NTN, Koyo and Nadella. If you’d like to learn more about us or need some assistance choosing the right slewing ring for your application, please send us a message or call +44 (0)1952 222100.

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