NSK45TAC100BSUC10PN7B-AV2SBall Screw Support Bearing – 45 mm Bore, 100 mm OD, 20 mm Width, 60 Degree Contact Angle, Sealed Both Sides, Heavy Preload, ABEC 7

Product Description

What this part is

An NSK ball screw support bearing, 45 mm bore, 100 mm outside diameter, 20 mm width. Ball screw support bearings are a distinct family from ordinary angular contact ball bearings and are commonly mistaken for them because they share the angular contact geometry. They are built specifically to take the axial thrust reaction at the end of a ball screw, with a steep contact angle, a thick sealed section and a high static rating relative to the envelope.

Decoding the designation

In 45TAC100BSUC10PN7B-AV2S the leading 45 is the bore in millimetres and the 100 following the family code is the outside diameter in millimetres, so the designation states its own boundary dimensions. TAC is NSK’s ball screw support series and carries a 60° contact angle. B is the design series. SU marks the bearing as single universally ground, so any number of them may be stacked and will develop the specified preload when clamped. The remaining characters are factory precision, seal and lubrication specifications; the precision level is ABEC 7.

What a 60° contact angle buys

Contact angle sets how a ball bearing divides load between the radial and axial directions. At 60° the ball path is steep and almost all capacity is axial, which is exactly the duty of a ball screw end support — the screw generates thrust and very little radial load. The trade is speed and radial capacity: a 60° bearing has a lower limiting speed than a 15° or 25° spindle bearing of the same envelope because the steeper path raises ball spin and gyroscopic moment, and its radial capacity is modest. Substituting an ordinary 15° or 25° angular contact bearing into a screw support position gives away most of the axial stiffness the position needs.

Load ratings and speed

Dynamic load rating 62 kN (13,938 lbf), static load rating 115 kN (25,853 lbf), limiting speed 3,000 rpm. The static figure exceeding the dynamic figure is normal in this family and reflects the steep angle and heavy ball complement.

Sealing and lubrication

Contact rubber seals on both faces, grease lubricated from the factory. Sealing is standard on the TAC family because a screw end support sits at the end of a machine axis where coolant and swarf reach it, and the sealed and pre-greased construction removes the need for a separate lubrication path to the bearing bore.

Quantity and configuration

1 Pc. Universally ground single bearing. Two or three stacked in tandem multiply axial capacity and stiffness in the loaded direction, which is the usual arrangement at the fixed end of a ball screw.

Fitting notes

Preload is developed by clamping the ground ring faces, so the housing shoulder and the screw-end locknut are the datum and the clamp load must reach the faces squarely. The ring-face marking establishes the orientation when several are stacked.

Interchange guidance

Other makers’ 60° screw support bearings in this envelope: Timken MM45BS100. The SKF BSD, FAG 7603-series TVP and NTN BST families also use a 60° angle. A 7209-type angular contact bearing at 15° or 25° shares the envelope but not the load split, so it is not a substitute.