NSK150TAC20DPN7+LC7Ball Screw Support Thrust Angular Contact Bearing Matched Set 150 x 225 x 90 mm, 60° Contact Angle, Duplex Back-to-Back Mounting, Precision N7, 2 Pieces

Product Description

What this part is

A matched set of NSK thrust angular contact ball bearings from the TAC ball screw support range — 150 mm bore, 225 mm outside diameter, 90 mm overall width across the set. This is a distinct family, not an ordinary angular contact spindle bearing, and it is regularly mistyped as one. The TAC series is purpose-built to sit behind a heavily loaded ball screw or a vertical spindle and take axial load with very high stiffness.

Decoding the designation

150 — bore diameter, 150 mm.
TAC — NSK thrust angular contact ball bearing for ball screw support. The defining feature of the family is a steep 60° contact angle.
20 — series code within the TAC range, setting the section and ball size.
D — duplex. The bearings are ground and supplied as a matched set for back-to-back mounting.
+L — supplied with the matched spacer arrangement for the set.
PN7 — NSK precision designation for this range.
LC7 — NSK preload and clearance code for the set, carried here as a searchable reference.

What these specs mean in practice

The 60° contact angle is the whole point of the family. At 60° the load line runs much closer to the bearing axis than in a 15° or 25° spindle bearing, so almost all of the capacity is axial and axial stiffness is very high. That is exactly what a ball screw axis needs: positioning accuracy under cutting load is governed by the axial deflection of the screw support, and a soft or backlash-prone support turns straight into lost accuracy, following error and chatter, no matter how good the screw, the drive and the encoder are.

What you give up is speed and radial capacity. A steep-angle thrust bearing generates more heat per revolution than a shallow-angle spindle bearing and is not intended to carry meaningful radial load — the screw or shaft needs its radial support elsewhere. Do not substitute a 60° screw support bearing for an ordinary angular contact bearing, or the reverse; they are built for opposite jobs.

Mounted back to back as a duplex set, the two bearings’ load lines diverge outwards, so the set takes thrust in both directions with no play and resists the tipping moment a long screw puts into its support. The matched spacer arrangement sets the preload without any shimming or measuring on assembly.

Quantity and configuration

This listing is a matched set of 2 pieces, the D duplex designation, with the spacer arrangement indicated by the +L element. The 90 mm figure is the overall width across the assembled set, not the width of one bearing. Keep the set together and keep it in its marked orientation — the components are ground as a matched group, and mixing pieces between sets destroys the preload and the axial accuracy that make the bearing worth specifying.

Fitting notes

The axial accuracy of a thrust angular contact set is only as good as the faces it sits against. Both abutment faces — the shaft shoulder and the housing face — need to be ground square to the axis, because an out-of-square face tips the rings and loads one row harder than the other. Clamp the set firmly and evenly against its shoulder; this is a bearing designed to be axially clamped, not floated. At 150 mm bore, plan the handling and use controlled heat rather than force to fit the inner rings, and never drive load through the balls. Lubricate with a grease or oil suited to a heavily loaded, comparatively slow-turning thrust position rather than a high-speed spindle grease, and do not overfill.

Interchange guidance

Ball screw support bearings are their own family, and the equivalents come from the corresponding ranges rather than from ordinary 70xx numbers: FAG 7602…TVP and the FAG 2344xx double-direction axial angular contact series, NTN BST, Timken MM…BS, RHP BSB, and INA/Schaeffler ZKLN and ZKLDF — all built around a steep contact angle for the same job, though sizes and mounting details differ. Within NSK, 150TAC20X+L is the corresponding execution variant and the BA series (for example 70BA10X) is NSK’s other screw-support family. When cross-referencing, match the bore, the overall set width and the contact angle; a 60° screw support bearing and a 25° spindle bearing of the same bore are not interchangeable in either direction.