Lubrication of high-speed high-temperature thrust ball bearings : G. S. Reichenbach, J. B. Accinelli, and S. J. Beaubien. ASLE Transactions, v. 1, no. 2, Oct. 1958, p. 259–265

Abstract

The speed parameter, DN value, of most bearing is limited to 350 thousand whether they are hydraulic or anti-friction type. The new method of oil-air lubrication could increase it up to one million recently, however, it is difficult to change its speed variablly.The developed hybrid bearing, composed of aerostatic and angular contact ball bearings in a serial arrangement could work from 0 to 10 thousand rpm with the spindle diameter of 100 mm.When the applied radial force being lower than the load capacity of aerostatic bearing as in the case of finish or high speed cuts, the spindle is supported aerostatically. Once it exceeds the pre-load of ball, the spindle deflects radially about 10 um until making contact with the inner race of ball bearing as in the case of rough and heavy cut, when the spindle is supported rigidly by the angular contact balls.Either the circumference of spindle and the inner race of ball bearing are made of aluminum ceramics to prevent an occurrence of seizure. The spindle can quill out and in, which give an additional benefit of Z motion, whether it is supported aerostatically or anti-frictionally.The prototype HC machine tool could successfully machine aluminum alloys at 10 thousand rpm and steels at several hundred rpm by end mills.