Slewing bearing
Encyclopedia
To "slew" means to turn without change of place; a "slewing" 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
.
Compared to other rolling-element bearings, slewing bearings are thin in section and are often made in diameters of a metre or more; the slewing bearings on the Falkirk Wheel
are 4 metres diameter and fit over a 3.5 metre axle. Slewing bearings resemble oversize aircraft control surface bearings.
Slewing bearings often use two rows of rolling elements. They often use three race
elements, such as an inner ring and two outer ring "halves" that clamp together axially.
Slewing bearings are often made with gear teeth integral with the inner or outer race, used to drive the platform relative to the base.
Rolling-element bearing
A rolling-element bearing, also known as a rolling bearing, is a bearing which carries a load by placing round elements between the two pieces...
that typically supports a heavy but slow-turning or slow-oscillating load, often a horizontal platform such as a conventional crane
Crane (machine)
A crane is a type of machine, generally equipped with a hoist, wire ropes or chains, and sheaves, that can be used both to lift and lower materials and to move them horizontally. It uses one or more simple machines to create mechanical advantage and thus move loads beyond the normal capability of...
, a swing yarder
Swing yarder
A swing yarder is a mobile piece of heavy duty forestry equipment used for pulling logs from the woods to a logging road with cables. The swing yarder is also known as a grapple yarder....
, or the wind-facing platform of a horizontal-axis windmill
Windmill
A windmill is a machine which converts the energy of wind into rotational energy by means of vanes called sails or blades. Originally windmills were developed for milling grain for food production. In the course of history the windmill was adapted to many other industrial uses. An important...
.
Compared to other rolling-element bearings, slewing bearings are thin in section and are often made in diameters of a metre or more; the slewing bearings on the Falkirk Wheel
Falkirk Wheel
The Falkirk Wheel is a rotating boat lift located in Scotland, UK,connecting the Forth and Clyde Canal with the Union Canal, opened in 2002. It is named after the nearby town of Falkirk which is in central Scotland...
are 4 metres diameter and fit over a 3.5 metre axle. Slewing bearings resemble oversize aircraft control surface bearings.
Slewing bearings often use two rows of rolling elements. They often use three race
Race (bearing)
The rolling-elements of a rolling-element bearing ride on races. The large race that goes into a bore is called the outer race, and the small race that the shaft rides in is called the inner race.-Manufacture:...
elements, such as an inner ring and two outer ring "halves" that clamp together axially.
Slewing bearings are often made with gear teeth integral with the inner or outer race, used to drive the platform relative to the base.