SKF71904 CD/P4ADGAAngular Contact Ball Bearing — Super-Precision P4A Matched Pair, 20 mm ID, 37 mm OD, 9 mm Width, 15° Contact Angle, Extra Light Preload 25 N

Product Description

What this part is:

SKF 71904 CD/P4ADGA is a matched set of two super-precision, high-capacity D design, single row angular contact ball bearings supplied at extra light preload. Bore Diameter: 20 mm. Outside Diameter: 37 mm. Overall Width: 9 mm per bearing. Total Width: 18 mm across the matched pair. Contact Angle: 15°. Unit Quantity: 2 Pcs.

Decoding the designation:

71904 — ISO 719 extra-light dimension series, bore code 04, giving a 20 x 37 x 9 mm envelope per bearing.

CD — high-capacity D design ground to a 15° contact angle.

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

DGA — universally matchable set of two bearings, extra light preload, 25 N.

Specifications:

Dynamic Load Rating: 9,750 N (matched set of two). Static Load Rating: 6,400 N (matched set of two). Fatigue Load Limit: 275 N. Limiting Speed: 45,000 rpm grease and 67,000 rpm oil-air, single-bearing figures before the arrangement speed reduction factor. Speed reduction factors: 0.81 back-to-back, 0.77 face-to-face, 0.9 spring-loaded tandem. Preload: Extra light, 25 N. Axial Stiffness: 22 N/µm back-to-back or face-to-face. Precision Class: ABEC 7 / P4A. Cage Type: outer-ring shoulder-guided. Ball Diameter: 4.762 mm. Balls per bearing: 15. Calculation factor f0: 9.8. Reference grease quantity: 0.45 cm³ per bearing. Bearing Material: Bearing steel. Rolling Elements: Ball. Seal Type: Open. Lubricant: none, supplied ungreased. Source: SKF product page 71904 CD/P4ADGA.

Dimensions and mounting:

Shoulder diameter of inner ring: 25.6 mm. Shoulder diameter of outer ring, large side face: 31.4 mm. Chamfer dimension r1,2: 0.3 mm minimum. Chamfer dimension r3,4: 0.2 mm minimum. Shaft abutment da and db: 22 mm minimum. Housing abutment Da: 35 mm maximum. Housing abutment Db: 35.6 mm maximum. Fillet radius ra: 0.3 mm maximum. Fillet radius rb: 0.2 mm maximum. Position of oil nozzle dn: 26.8 mm. Mounting Arrangement: universally matchable, back-to-back (DB), face-to-face (DF) or tandem (DT).

Compatibility and replacement:

Cross-references on the 20 x 37 x 9 mm 15° super-precision envelope: FAG B71904-C-T-P4S, NSK 7904CTYNSULP4, NTN 7904UCG/GNP4, RHP 7904CTDULP4, Koyo 7904C-5GLFGP4. Preload level and arrangement are carried by separate suffixes in each maker’s own scheme.

Frequently asked questions:

What are the dimensions of the SKF 71904 CD/P4ADGA?

Bore 20 mm, outside diameter 37 mm, width 9 mm per bearing and 18 mm across the matched pair.

What do DGA and P4A mean?

DGA is a universally matchable set at extra light preload, 25 N. P4A is SKF super-precision tolerance class P4A.

What are the load ratings?

SKF publishes 9,750 N dynamic and 6,400 N static for the set of two, with a 275 N fatigue load limit.