RHPBSB150QUHEP7Ball Screw Support Bearing Quad Set – 1-1/2 in ID, 72 mm OD, 5/8 in Width, Open, 60° Contact Angle, Heavy Preload, 4 Pcs

Product Description

What this part is

RHP BSB150QUHEP7 ball screw support bearing set. Bore: 1-1/2 in (38.1 mm). Outside diameter: 72 mm. Width: 5/8 in (15.875 mm) per bearing. Series: BSB. Four single-row 60° ball screw support bearings, straight bore, open, supplied as one matched quad set.

Decoding the designation

Contact Angle: 60°. Family: BSB, the RHP ball screw support series. Grouping: QU, matched quad set. Preload: Heavy. Cage: machined laminated phenolic. Precision Grade: EP7, equivalent to P4, ABEC 7 and ISO Class 4. Also written BSB 150 QUH EP7 and BSB150QUH.

What these specs mean in practice

A ball screw support bearing is built for thrust, not radial load. The 60° contact angle is steeper than any standard angular contact bearing and it puts almost the whole load path along the screw axis, which is what a ball screw feed drive needs. Static radial load rating (C0r): 56,000 N. Dynamic radial load rating (Cr): 29,000 N. Limiting speed: 4,000 rpm. Heavy preload holds the axial stiffness that positioning accuracy depends on, because any axial slack in the support bearing shows up directly as lost motion at the tool. Four bearings in one stack multiply that stiffness and split the thrust between them. Maximum recommended operating temperature: 120 °C. Rings and balls are chrome bearing steel.

Quantity and configuration

4 Pcs, one matched quad set, sold together. The set is ground as a unit to deliver the heavy preload when the four rings are clamped up, so the four bearings belong together and mount in the order they are marked.

Bore form and mounting

Straight 1-1/2 in bore, open on both faces. Mass: 0.70 lb (0.32 kg) per bearing. Ball screw support bearings normally sit in a fixed end housing at one end of the screw, clamped between a shoulder and a locknut, with the far end carried on a simple floating bearing.

Interchange guidance

NSK 38TAC72B is the 60° ball screw support bearing on the same 38.1 x 72 mm size, sold as single bearings. The common metric 45 x 72 mm parts, such as FAG 7602045-TVP, SKF BSD 4572 and NSK 45TAC72B, share the outside diameter but have a 45 mm bore and will not fit a 1-1/2 in shaft. The RHP BSB inch series carries the bore in the designation, so BSB150 is the 1-1/2 in size.