RHP7018CTDUMP4Matched Duplex Pair Angular Contact Ball Bearings 90x140x24 mm 15° Medium Preload ABEC 7

Product Description

What this part is

RHP 7018-C-T-DUM-P4, a matched duplex pair of single-row angular contact ball bearings. Boundary dimensions 90 mm bore × 140 mm outside diameter × 24 mm width per bearing.

Decoding the designation

70 – single-row angular contact ball bearing, ISO dimension series 10
18 – bore code, 18 × 5 = 90 mm bore
C – 15° contact angle in the RHP scheme
T – phenolic cage
DU – duplex, a pair ground to run together
M – medium preload
P4 – ABEC 7 precision class

What these specs mean in practice

A 15° contact angle favours speed and radial stiffness over thrust capacity, which is why it is the usual machine-tool spindle angle. Mounted as a duplex pair the set locates the shaft in both directions and runs under a built-in medium preload, so the ring faces are ground with a matched offset and the two bearings clamp against each other rather than against a shim stack. Medium preload raises axial and radial stiffness above a light-preload set and generates more heat at the same speed. ABEC 7 controls bore, outside diameter and running accuracy to super-precision limits.

Published specifications

Bore: 90 mm (3.5433 in)
Outside diameter: 140 mm (5.5118 in)
Width: 24 mm (0.9449 in) per bearing
Total width mounted: 48 mm (1.8898 in)
Contact angle: 15°
Rows: 1 per bearing
Preload: medium (M)
Precision class: P4 (ABEC 7), RHP equivalent EP7
Cage: phenolic
Closure: open

Quantity and configuration

2 Pcs, one matched duplex pair.

Fitting notes

The pair goes on as a unit with the ground faces together, in the orientation marked on the outer rings, so the preload is set by the grinding rather than by clamp-up force. Clamping the inner rings solid against a shaft nut and the outer rings against the housing shoulder is what develops the designed preload. Splitting the pair across two positions loses the matching.

Interchange guidance

Same-spec 15° medium-preload duplex equivalents in other schemes: Fafnir 2MM9118WI-CR-DUM, RHP B-series B7018X2TADUMEP7, NSK 7018CTRDUMP4, FAG B7018-C-T-P4S-UM. Light-preload DUL and heavy-preload DUH forms, the 25° 7018-E form, and single SU bearings are related sizes in the same envelope rather than interchanges.