Uses of Ball Bearings. The claims made for the use of ball bearings in preference to plain bearings are several in number as follows: Less wear, less frictional resistance, more compact, non-heating in use, less fitting than plain bearings, better shaft alignment. Until recently very little reliable information could be obtained relative to ball bearings and today it is probable that their use on machine tools is much less than it should be. Their extended use on motor cars and bicycles has shown definitely just what their value is in such lines, but machine tool builders have probably been ultra-conservative in their use. In the high- speed drilling machines, their use has been remarkably successful. Any of the reliable manufacturers of such bearings will furnish performance figures showing the possibilities of their use.
Fig. 393. Auburn Self-Contained Ball Thrust Bearing Courtesy of Auburn Ball Bearing Company, Rochester, New York.
Fig. 394. Hess-Bright Thrust Bearing with a Lining Washer and Enclosing Case.
Types of Bearings. Ball bearings are known generally under two headings: "Radial" and "Thrust". In the radial bearing, the load pressure is at right angles or normal to the shaft axis, while in the thrust bearing the load pressure is parallel to the axis, or, in other words, the pressure is axial.
Fig. 393 is representative of the usual thrust bearing, while Fig. 394 illustrates diagrammatically the Hess-Bright thrust bearing with ball separating retainers.
Figs. 395 and 396 are representative of the best type of radial ball bearings. Radial ball bearings are made in what is known as the single type and the double type. In other words, bearings may be obtained with either a single row or race of balls, or they may be obtained with two rows of balls. While radial bearings are not generally supposed to take an axial load or thrust, many of the better radial types will allow a certain amount of axial thrust under favorable conditions.
Tables XXIII and XXIV give load carrying capacities of radial and of axial ball bearings used under light, medium, and heavy loading.
While it was at one time thought that ball bearings needed no lubrication, this was
Fig. 315. S. K. F. Radial Ball Bearing.
Fig. 396. S. K. F. Radial Bearing Showing Parts and Assembled Bearing Complete.
Revolutions per Minute
Maximum Load, Pounds