NSKBall Screw Support Bearing 35x72x15 mm, 60° Contact Angle, Heavy Preload, Universally Ground, Straight Bore

Product Description

What this part is

A ball screw support bearing in the 35 mm bore × 72 mm outside diameter × 15 mm width envelope. Single row, full ball complement, ground to a 60° contact angle with a straight bore, and universally ground so it can be matched with like bearings.

Decoding the order code

In 35TAC72BSUC10PN7B the leading 35 is the bore in millimetres and TAC72B identifies the TAC B series at a 72 mm outside diameter. SU marks a single universally ground bearing, C10 is the preload code, giving heavy preload, and PN7B is the NSK precision and design class. The TAC element is the part that matters most: it marks this as a ball screw support bearing rather than an ordinary angular contact bearing.

Why this is a separate family

Ball screw support bearings are a distinct type, and they are frequently catalogued as ordinary angular contact bearings because they share the 7000-style appearance. The difference is the contact angle and the ball count. At 60° the load line runs steeply toward the axis, so almost all of the capacity is axial and very little is radial, which is the opposite balance to a 15° spindle bearing. Combined with a full complement of balls, that produces the very high axial stiffness a ball screw needs to hold position under reversing thrust without backlash.

What these specs mean in practice

A ball screw’s accuracy depends on how little the screw end moves axially under load, so axial stiffness at the support bearing translates directly into positioning accuracy and reduced tool deflection. The 60° angle and full ball complement buy that stiffness, and the cost is radial capacity and limiting speed. Frictional torque is lower than a cylindrical or tapered roller arrangement of similar capacity, so the drive needs less breakaway force. Heavy preload removes all axial play and is what makes the mounting backlash-free.

Thrust direction

A single row at 60° carries thrust in one direction only. Ball screw ends reverse, so these bearings are normally mounted as an opposed pair or a larger universally ground stack, giving stiff location in both directions.

Quantity and configuration

1 Pc. One single universally ground bearing, open on both faces.

Interchange guidance

Other makers’ 60° ball screw support bearings in the 35 x 72 x 15 mm size: FAG 7602035-TVP, Timken MM35BS72 and RHP BSB035072. Within NSK, 35TAC72CSUHPN7C is the newer C series, and 35TAC72BDFC10PN7A is the factory-matched face-to-face pair rather than a single. An ordinary 7207 angular contact bearing shares much of this envelope but is a different part, since its contact angle and ball count give it a fraction of the axial stiffness.