Thrust bearing

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A thrust bearing is a particular type of bearing. Most commonly used in automotive applications, the characteristic that makes it distinct is that it can cope with axial thrust - along the axis of the shaft that it supports. This is necessary because the forward gears in modern car gearboxes use helical gears which, while aiding in smoothness and noise reduction, cause axial forces that need to be dealt with. Citroen invented a double helical gear which neutralised the thrust caused by normal helical gears.

Thrust bearings come in several varieties.

Ball thrust bearings, comprised of ball bearings supported in a ring, can be used in low thrust applications where there is little radial load.

Roller thrust bearings consist of small rollers arranged so that their axes all converge at a point on the axis of the bearing. They can support larger thrust loads than the ball type, but still relatively little in terms of radial load.

Tapered roller bearings are the type most commonly used in automotive applications, where they are used in pairs to accommodate axial thrust in either direction, as well as radial loads.

One specific thrust bearing in an automobile is the clutch 'throw out' bearing, sometimes called the clutch release bearing).

Thrust bearing

See also