MRC7209PJDUAngular Contact Ball Bearing 45x85x19 mm 29 Degree Contact Angle Duplex Ground Open

Product Description

What this part is:

An MRC 7209PJDU single-row angular contact ball bearing, 45 mm bore, 85 mm outside diameter, 19 mm width. The inner and outer raceways are offset so the ball load line runs at an angle to the radial plane, which lets the bearing carry a radial load together with a thrust load acting in one direction. The ring faces are ground for duplex mounting, so two bearings can be set face to face, back to back or in tandem and share the load as a preloaded unit.

Decoding the designation:

MRC numbers this family 72xx, where 72 is the ISO medium angular contact dimension series and 09 is the bore code, giving 45 mm. DU is MRC’s duplex designation: the faces are universally ground so a pair butts up to a controlled offset. MRC’s angular contact scheme is its own, not the ISO one, and the PJ element does not resolve to a published MRC suffix meaning; it is carried here as a searchable designation rather than as a specification.

Contact angle:

MRC ground its 7000-series angular contact bearings at a nominal 29° contact angle. That is a distinct value from the 40° that a 7209 B in the FAG or SKF scheme carries and from the 15° of a 7209 C. At 29° the bearing takes appreciably more axial load than a 15° design of the same size and appreciably less than a 40° one, and it runs at a higher speed limit than the 40°. Because the angle governs how a duplex pair preloads and how the axial load divides between the rows, an MRC 7209 and an ISO 7209 B are not the same bearing.

Quantity and configuration:

Bearing only, open, no shields and no seals. No lockwashers, spacers, locknuts or shaft and housing hardware.

Fitting notes:

An angular contact bearing carries thrust in one direction only, so the wide face of the outer ring is the thrust-taking face and its orientation on the shaft sets the direction of axial support. In a duplex mounting the ground faces are butted with no shim between them, and the arrangement chosen — back to back for rigidity against moment loads, face to face for tolerance of misalignment, tandem for doubled one-way thrust — determines the resulting preload.

Cross-reference guidance:

7209PJDU, 7209-PJ-DU and 7209 PJ DU are the same designation written three ways. A 7209 in another maker’s angular contact scheme shares the 45 x 85 x 19 mm envelope but not the contact angle: SKF 7209 BEP and FAG 7209 B are 40°, SKF 7209 ACD and NSK 7209A5 are 25°, and NSK 7209C and Fafnir 2MM209WI are 15°. Those are related sizes only, because swapping contact angle changes the axial rating, the preload developed in a pair and the speed limit. The MRC 7209SU is the single-mount grind of the same bearing and is likewise a related part, since SU and DU grinds are mutually exclusive.