3- and 4-Contact Point Spindle Bearings – a new Approach for High Speed Spindle Systems

One important demand on spindle systems in modem machine tools is to realise higher rotational speeds in order to increase the machining efficiency. In conventional spindle bearings the contact angles on inner and outer ring deviate extremely from one another with rising rotational speeds due to centrifugal forces. Axial shift of trie inner ring (elastic mounted bearing) and increasing normal forces in the contact zones on the outer ring are typical consequences leading to high internal bearing loads and a reduced life span. Based on these problems bearings with a new inner geometry are studied. Instead of two contact zones these bearings have three or four contact zones to ensure constant contact angles and reduced normal forces on the outer ring. In this paper analytic operation studies and first experimental tests are presented.