RHP7018CTSULP4Super Precision Angular Contact Ball Bearing 90x140x24 mm 15° ABEC 7 Light Preload

Product Description

What this part is

A single-row super-precision angular contact ball bearing, 90 mm bore, 140 mm outside diameter, 24 mm width. It carries a 15° contact angle and a machined phenolic laminate cage, and its faces are universally ground to a light preload band so any two pieces of this designation stack directly into a preloaded set.

Decoding the designation

The 70 prefix and bore code 18 give ISO dimension series 70 at a 90 mm bore. In the RHP scheme C is a 15° contact angle, T a machined phenolic laminate cage, SU a universally ground single, L the light preload grade, and P4 super-precision tolerances to ABEC 7 / ISO class 4. Three further carton designations agree with that reading: the RHP B-series number B7018X2TAULEP7, in which X2 is 15° and EP7 is the ABEC 7 class, and the Fafnir-scheme number 2MM9118WI-CR-SUL, in which the 2MM prefix is 15° and CR is a phenolic outer-land-riding cage.

What these specs mean in practice

A 15° contact angle is the speed-biased choice at this size. The shallow load line keeps ball centrifugal and gyroscopic effects low, so a 15° bearing reaches a higher limiting speed and runs cooler than a 25° bearing of the same envelope, trading axial capacity and axial stiffness for that. At a 90 mm bore, where surface speed at the ball track is already high, that trade matters more than it does on a small bearing.

Light preload is the low-heat end of the preload scale. Preload removes internal play, fixes the contact angle and makes axial position and runout repeatable; the friction it adds becomes heat in the rings, and that heat changes the preload as the spindle warms. The L grade adds the least, which suits fast, moderately loaded spindles and grinding heads.

The phenolic laminate cage riding on the outer ring land is the high-speed cage arrangement. Phenolic is light, so cage inertia and ball-pocket loads stay low, and it retains an oil film well; land guidance keeps the cage running true at speed rather than wandering on the ball set. Phenolic sets the temperature ceiling at roughly 120 °C, ahead of the steel.

Quantity and configuration

1 Pc. Universally ground single (SU), open on both faces.

Thrust direction

A single-row angular contact ball bearing carries thrust in one direction only. Axial load in the opposite direction is taken by a second bearing opposing this one, or by another element in the shaft stack.

Fitting notes

Universal grinding means two pieces of this designation clamp solid to give the light preload directly, back-to-back, face-to-face or in tandem, with no shimming. Mounting orientation follows the face marks, with the thrust face toward the load. Shaft and housing seats at this class are ground and measured, typically j4 to k4 on the shaft and H5 to J5 in the housing, and cleanliness governs the result, since the preload band is a few microns of axial interference.

Interchange guidance

B7018X2TAULEP7 is the RHP B-series form of this envelope and angle, and 2MM9118WI is the Fafnir-scheme number for the same 15° 70-series size. Same-envelope bearings differing in contact angle, preload grade or tolerance class — 7018E at 25°, the medium and heavy preload grades, and P0 or P5 class pieces — are related sizes rather than interchanges. A duplex-ground DU piece of this size is a different item, since DU faces are relieved for a specific pair stack height.