NSK7005ATYDBC7P5High Precision Angular Contact Ball Bearing Matched Back-to-Back Pair (2 Pcs), 25 x 47 x 12 mm, 30 Degree Contact Angle, ABEC-5 P5, Polyamide Cage

Product Description

What this part is

A matched back-to-back pair of NSK high-precision angular contact ball bearings, 25 mm bore, 47 mm outside diameter, 12 mm wide each. Both carry a 30° contact angle, are ground to ISO Class 5 (ABEC 5) and run a ball-guided polyamide resin cage. The combination suits thrust-and-position duty: ball screw ends, precision gearbox and pump shafts, spindle and rotary-table assemblies where axial location matters as much as radial support.

Designation breakdown

Decoded against NSK’s own numbering system for high-precision angular contact ball bearings. Suffixes are brand-specific and this decode does not transfer to SKF, FAG or Timken numbers. 7005: single-row angular contact ball bearing, 70 (10) dimension series, bore number 05 for a 25 mm bore, 47 mm outside diameter, 12 mm width. A: 30° contact angle, NSK’s scheme running C = 15°, A5 = 25°, A = 30°. TY: ball-guided polyamide resin cage, written TYN in NSK’s current catalogue and rated to dmn 1,400,000 with a 120°C operating limit; TY is the form printed on this carton. DB: back-to-back duplex arrangement, the O configuration, the opposite hands being DF face-to-face and DT tandem. C7: a preload call-out, given as light preload in NSK/RHP designation code lists. P5: ISO tolerance class 5, equivalent to ABEC 5. The carton also carries UB-13. Ring markings read 7005, NSK, JAPAN.

Back-to-back arrangement

Mounted back-to-back, the two contact-angle lines diverge outward, so the effective load centres sit further apart than the bearing width. That gives a DB pair its resistance to moment (tilting) loads and its ability to take thrust in either direction from one bearing station. Face-to-face has the load lines converging and is more forgiving of shaft-and-housing misalignment but much weaker in moment. Tandem stacks both angles the same way to double one-direction thrust and takes nothing in reverse.

The 30° angle is the high-thrust end of NSK’s standard precision range. Against a 15° bearing it carries substantially more axial load and is axially stiffer, at a lower speed ceiling and lower radial rigidity.

The polyamide cage is light and quiet and tolerates momentary lubrication starvation better than steel, with a 120°C limit. Polyamide is also sensitive to long exposure to certain synthetic oils and EP additives, where a phenolic (TR) or machined cage version applies.

Published ratings

Bore (d): 25 mm. Outside diameter (D): 47 mm. Width (B): 12 mm per bearing, 24 mm for the pair mounted. Contact angle: 30°. Basic dynamic load rating (Cr): 13,500 N per bearing. Basic static load rating (C0r): 6,850 N per bearing. Permissible axial load (Pa): 4.55 kN. Limiting speed: 20,900 rpm grease-lubricated, 27,800 rpm oil or oil-air. Tolerance class: P5 (ISO Class 5 / ABEC 5). Cage: polyamide resin, ball guided. Closure: open, no seals and no shields. Rows: one per bearing. Mass: approximately 0.079 kg per bearing, approximately 0.158 kg for the pair. NSK’s published preload steps for this bearing size are EL 25 N (63 N/µm axial rigidity), L 135 N (112), M 299 N (149) and H 507 N (183). Limiting speeds are catalogue figures for the bearing alone; a preloaded DB pair in a housing runs lower.

Mounting data

Effective load centre (a): 16.4 mm. Shaft abutment diameter (da min.): 30 mm. Housing abutment diameter (Da max.): 42 mm. Housing abutment diameter (Db max.): 44.5 mm. Fillet radii: r min. 0.6 mm, r1 min. 0.3 mm, ra max. 0.6 mm, rb max. 0.3 mm. Recommended grease quantity: 0.48 g per bearing. Each outer ring has a thick land on one face and a thin land on the other, the two thin marked faces sitting outward in a back-to-back arrangement. The pair is ground as a set, so the designed preload arises from clamping the rings solid, with no shims, ground spacers or preload adjustment.

Quantity and configuration

This listing supplies two bearings, one matched DB set, in the original NSK carton with the factory handling slip, sealed in the NSK poly bag. The photographs show both bearings still bagged together.

Interchange guidance

Same-envelope 25 x 47 x 12 mm precision equivalents include SKF 7005 ACD/P4ADGA and 7005 ACDGA/P4A, both at a 25° angle and so an envelope match rather than an angle match, FAG B7005-E-T-P4S-DB, FAG 7005-B-XL-TVP for the standard-tolerance version, NTN 7005ADB and Nachi 7005ADB. NSK’s own related numbers are 7005AW (pressed-steel cage, standard tolerance), 7005A5 (25°) and 7005C (15°), the last two being different contact angles. RHP precision bearings were absorbed into NSK, so an RHP number in an older machine manual may legitimately land here.