Angular Contact Ball Thrust Bearings






     For the main spindles of machine tools, good high-speed performance and high rigidity are required for the ball bearings used in
     combination with double-row cylindrical roller bearings. For these applications, to allow selection appropriate for the characteristics
     of the machine, NSK provides three types of bearings.
     All these bearings have special outer ring outside diameter tolerances (P4A Class and P2A Class) to provide clearance between the
     outer ring periphery and housing bore in order to avoid any load. NSK’s ROBUST series high-speed angular contact thrust ball
     bearings are capable of high-speed operations while maintaining high rigidity. Ball diameter and number of balls are the same as
     TAC type bearings. BTR type bearings have a 40° contact angle, and BAR type bearings have a 30° contact angle. The result is
     superior high-speed performance that minimizes heat generation.


     Angular Contact Thrust Ball Bearings  (267 KB)




     Customers can easily replace their TAC20D series bearings with NSK’s BAR type or BTR type bearings without having to change
     the shaft or housing of the machine tool spindle. Both types of bearings have unique width dimensions that accommodate a new
     spacer D, which replaces the older one C (see Fig. 3.1).

     Contact Angle

     For the differing contact angles, TAC type bearings rank highest in levels of rigidity, closely followed by BTR type bearings, with BAR
     type bearings coming in last. For temperature rise of the outer ring, however, this ranking is reversed with BAR type bearings having
     the highest tolerance, followed by BTR type bearings, and finally TAC type bearings with the least tolerance.
     Be sure to select the product that will best meet the needs of your specific operating conditions.