Spherical bearing

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Spherical bearing using rolling elements
Spherical bearing using rolling elements

A spherical bearing is a bearing that permits angular rotation about a central point in two orthogonal directions within a specified angular limit based on the bearing geometry. Typically these bearings support a rotating shaft in the [bore] of the inner ring that must move not only rotationally, but also at an angle.

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[edit] Construction

Construction of spherical bearings can be hydrostatic or strictly mechanical. A spherical bearing by itself can consist of an outer ring and an inner ring and a locking feature that makes the inner ring captive within the outer ring in the axial direction only. The outer surface of the inner ring and the inner surface of the outer ring are collectively considered the raceway and they slide against each other, either with a lubricant or a maintenance-free PTFE [Teflon] based liner. Some spherical bearings incorporate a rolling element such as a race of ball-bearings, allowing lower friction.

[edit] History

The Swede Sven Wingquist (1876–1953) invented the spherical bearing in 1907. He founded a global company, SKF (AB Svenska Kullagerfabriken), still the world’s leading producer of industrial bearings.

[edit] Application

Spherical bearings are used in countless applications, wherever rotational motion must be allowed to change the alignment of its rotation axis. A prime example is a tie rod on a vehicle suspension. The mechanics of the suspension allow the axle to move up and down, but the linkages are designed to control that motion in one direction only and they must allow motion in the other directions. Spherical bearings have been used in Computer mice, car suspensions, trackballs, driveshafts, heavy machinery, sewing machines, and many other applications.

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