FAGSuper-Precision Angular Contact Ball Bearing – 85 mm ID, 150 mm OD, 28 mm Width, Open, 15° Contact Angle, P4S, Universally Matchable Medium Preload

Product Description

What this part is

A FAG B7217C.TPA.P4S.UM super-precision angular contact ball bearing in the 85 x 150 x 28 mm envelope, ISO base number 7217. Single row, 15° contact angle, universally matchable and ground for medium preload, with a one-piece laminated fabric cage.

Decoding the designation

B identifies the FAG super-precision spindle bearing range; it is not the 40° B-series used on standard angular contact bearings. 7217 is the ISO 72 medium series at 85 mm bore, a heavier cross-section than the 70 series on the same bore. C is the 15° contact angle. TPA is a one-piece machined cage in fabric-base laminate, a phenolic material. P4S is Schaeffler’s super-precision class, held tighter than P4 to ISO 492. UM is a universally matchable bearing ground for medium preload, supplied as a single bearing. The K5 element carried on this carton string is an unpublished code and no specification is read from it.

What these specs mean in practice

The bearing carries radial load and axial load in one direction, so two or more are stacked to locate a spindle in both directions. The 15° angle is the high-speed setting: less thrust capacity than a 25° bearing on the same envelope, but a higher limiting speed and less heat generated. Medium preload trades some speed for stiffness — preload force is 1,786 N and axial rigidity 167 N/µm, against 568 N and 99 N/µm for the light class on the same bearing. The 72 series cross-section gives this bearing a basic dynamic load rating of 97.0 kN and a basic static load rating of 59.0 kN, well above a 70 series bearing on the same bore. A laminated fabric cage is dimensionally stable, runs quietly and holds oil within the cage body. Limiting speed is 9,000 rpm on grease and 15,000 rpm on oil. Operating temperature range is −30 °C to 100 °C.

Quantity and configuration

Sale unit is one piece. Universal matching means the ring faces are ground so that any two bearings from this range come up to the specified medium preload when clamped solidly, in a back-to-back, face-to-face or tandem stack, and this bearing also runs on its own.

Fitting notes

Shaft shoulder diameter is 98 mm and outer ring shoulder diameter 138 mm. Maximum recess radius is 2 mm at the shaft and 1 mm at the outer ring, against a minimum ring chamfer of 2 mm. Distance between the apexes of the pressure cones is 29.8 mm. The inner ring seats on a ground shaft with a light interference fit and the outer ring takes a close fit in the housing, each clamped against a face square to the axis. In a stack, preload is realised only once all inner rings and all outer rings are drawn solidly against their shoulders.

Interchange guidance

Same-specification parts on this envelope at 15°, super-precision, universally matchable medium preload include SKF 7217 CDGB/P4A and NSK 7217CTYNSUMP4. The 25° form of the same envelope, FAG B7217E.T.P4S.UM, is a related size rather than an interchange. Light and heavy preload variants of the same number are separate parts, as is the standard-precision 7217 in the same envelope.