ROLLER BEARINGS & BALL BEARINGS - Part 1

Ball Bearings cont.

Commercial unground ball bearings are available as radial, thrust, or combination types. Basically, these ball bearings are made of a machined or stamped inner race, a full complement of hardened steel balls, and an outer race of one, two, or more machined or stamped parts. Race and casing material is usually carbon steel.

Because surfaces are unground, and because some parts are stamped, the ball bearing has greater radial and axial freedom than a precision bearing.

Unground ball bearings generally are suited to light loads at low speeds. The lower the speed, the greater the ball bearing's load capacity. Generally, the ball bearings are not suited to speeds above 1,200 to 1,500 rpm. At these speeds, loads may range from 50 to 500 lb, depending on bearing size and construction. On the other hand, loads of 2,500 lb may be practical with a ball bearing operating at 50 rpm.

Misalignment has little effect on commercial unground ball bearing assemblies because of their greater internal clearances. Excessive misalignment destroys any bearing, but far less production accuracy is required with unground ball bearings. As a result, the entire assembly can be much simpler in construction than a precision bearing.

The major advantage of unground ball bearings over the higher precision ball bearings discussed earlier is price. Unground ball bearings are far less expensive than the higher precision types. On the other hand, life of unground ball bearings is less than precision bearings. Also, unground ball bearings generally feature inch rather than metric external dimensions. Unground ball bearings also operate at higher noise than precision bearings. This may be overcome, when necessary, by using a nonmetallic material on outer cases.

Roller Bearings & Ball Bearings

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