Limiting speeds and operating temperatures of fixed preload large bore angular contact ball bearings for machine tools

Abstract

Because of the ability of angular contact ball bearings to support both radial and axial loads and operate at high speeds, they are used widely to support machine tool spindles. The limiting speed of angular contact bearings depends on a number of factors including the type of bearing arrangement, preload, lubrication and bearing spacing. Preloaded back-to-back angular contact ball bearings are commonly used and in this paper the limiting speed of such an arrangement is considered together with a simple method for estimating speed factors which is shown to agree with actual experience. Also, little information is available on the operating temperatures of large angular contact bearings and so the effect of lubrication conditions on the limiting speed of angular contact bearings of 200 mm bore are investigated. In particular the design of the lubrication nozzle is shown to have a significant influence on the bearing operating temperature.