SKF7209ACDP4ADGBAngular Contact Ball Bearing — Super-Precision P4A Matched Pair, 45 mm ID, 85 mm OD, 19 mm Width, 25° Contact Angle, Light Preload 520 N

Product Description

What this part is

SKF 7209 ACD/P4ADGB is a matched set of two super-precision, high-capacity D design, single row angular contact ball bearings supplied at light preload. Bore Diameter: 45 mm. Outside Diameter: 85 mm. Overall Width: 19 mm per bearing. Total Width: 38 mm across the matched pair. Contact Angle: 25°. Preload: Light, 520 N. Precision Class: ABEC 7 / P4A. Rolling Elements: Ball. Number Of Rows: 1 per bearing. Bore Type: Straight. Seal Type: Open. Bearing Material: Bearing steel. Unit Quantity: 2 Pcs.

Decoding the designation

7209 — ISO 72 light dimension series, bore code 09, giving a 45 x 85 x 19 mm envelope per bearing.

ACD — high-capacity D design ground to a 25° contact angle. The wider angle carries more axial load per unit of radial load than the 15° CD execution on the same envelope.

P4A — SKF super-precision tolerance class P4A, ABEC 7 running accuracy.

DGB — universally matchable set of two bearings, light preload, 520 N.

What these specs mean in practice

Preload: Light, 520 N. Light preload gives defined axial and radial rigidity while keeping running temperature controlled at spindle speed. Axial stiffness: 190 N/µm in a back-to-back or face-to-face arrangement.

Dynamic Load Rating: 66,300 N. Static Load Rating: 60,000 N. Both are SKF set ratings covering the two bearings together. Fatigue load limit: 2,500 N. Ball diameter: 12.7 mm. Number of balls per bearing: 14. Reference grease quantity: 5.9 cm³ per bearing. The set is preload-adjusted at the factory and therefore carries no internal clearance class.

Limiting Speed: 15,000 rpm on grease and 24,000 rpm on oil-air, the SKF single-bearing figures before the arrangement speed reduction factor. For this 72 D series at this preload the factors are 0.75 back-to-back, 0.72 face-to-face, and 0.9 for a spring-loaded DT tandem set.

Load calculation factors published by SKF for this set: calculation factor e 0.68. Single and tandem: X1 1, X2 0.41, X0 0.5, Y1 0, Y2 0.87, Y0 0.38. Back-to-back and face-to-face: X1 1, X2 0.67, X0 1, Y1 0.92, Y2 1.4, Y0 0.76.

Mounting data

Shoulder diameter of inner ring: 57.3 mm on both the large and small side faces. Shoulder diameter of outer ring, large side face: 72.7 mm. Chamfer dimension r1,2: 1.1 mm minimum. Chamfer dimension r3,4: 0.6 mm minimum. Diameter of shaft abutment da and db: 52 mm minimum. Diameter of housing abutment Da: 78 mm maximum. Diameter of housing abutment Db: 80.8 mm maximum. Radius of fillet ra: 1 mm maximum. Radius of fillet rb: 0.6 mm maximum. Position of oil nozzle dn: 60.6 mm.

Quantity and configuration

Mounting Arrangement: universally matchable, back-to-back (DB), face-to-face (DF) or tandem (DT). Arrangement / Configuration: matched set of two at light preload. Unit Quantity: 2 Pcs. Cage Type: outer-ring shoulder-guided. Lubricant: none; the bearings are supplied ungreased. Snap ring included: No. Rings are one-piece inner and outer. Contact type: normal contact, two-point.

Interchange guidance

Equivalent 45 x 85 x 19 mm 25° super-precision executions: FAG B7209-E-T-P4S-UM, NSK 7209A5TYNDUMP4, RHP 7209A5TDUMP4. Preload level is carried by a separate suffix in each maker’s scheme, so match the preload step when substituting.