11/23/08

Tapered Roller Bearing

Tapered roller bearings are bearings that can take large axial forces (i.e. they are good thrust bearings) as well as being able to sustain large radial forces.
DescriptionThe inner and outer ring raceways are segments of cones and the rollers are also made with a taper so that the conical surfaces of the raceways and the roller axes if projected, would all meet at a common point on the main axis of the bearing.
This conical geometry is used as it gives a larger contact patch, which permits greater loads to be carried than with spherical (ball) bearings, while the geometry means that the tangential speeds of the surfaces of each of the rollers are the same as their raceways along the whole length of the contact patch and no differential scrubbing occurs. This avoids rapid wear and greatly reduces rolling friction.
The rollers are guided by a flange on the inner ring. This stops the rollers from sliding out at high speed due to their momentum.
The larger the half angles of these cones the larger the axial force that the bearing can sustain.
Tapered roller bearings are separable and have the following components: outer ring, inner ring, and roller assembly (containing the rollers and a cage). The non-separable inner ring and roller assembly is called the “cone”, and the outer ring is called the “cup”. Internal clearance is established during mounting by the axial position of the cone relative to the cup

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