RHP7217ETDULP4Super Precision Angular Contact Ball Bearing Matched Pair – Straight Bore, 85 mm ID, 150 mm OD, 28 mm Width, Open, 25° Contact Angle, Light Preload, ABEC 7

Product Description

What this part is

RHP 7217ETDULP4 matched pair of single-row super-precision angular contact ball bearings, made in England. Bore: 85 mm. Outside Diameter: 150 mm. Overall Width: 28 mm. Contact Angle: 25°. Precision Class: P4, equivalent to ABEC 7 and to BS292 EP7. Number Of Rows: 1 per bearing. Rolling Elements: Balls. Bearing Material: Carbon chrome bearing steel to BS970 534A99/535A99, equivalent to SAE 52100, through hardened. Series: 7200, ISO dimension series 02. RHP is an NSK brand.

Decoding the designation

Reading 7217-E-T-DUL-P4: 7 is a single-row angular contact ball bearing, 2 is ISO dimension series 02, the bore code 17 gives an 85 mm bore, E is the 25° contact angle, T is the laminated phenolic resin cage, DU marks a paired unit, L is light preload and P4 is the precision grade. The carton carries the B-series form 7217X3TDUEP7, where X3 is the 25° angle, and the Fafnir cross 3MM217WI DUL, where 3MM is 25°.

What these specs mean in practice

Dynamic Load Rating: 102.0 kN per bearing. Static Load Rating: 86.5 kN per bearing. Limiting Speed, oil-air lubrication: 12,500 rpm. Limiting Speed, grease lubrication: 8,100 rpm. Those figures are for a single bearing under light spring preload. Mounted as a back-to-back light-preload pair the limiting speeds are multiplied by 0.80, giving 10,000 rpm on oil-air and 6,480 rpm on grease. A 25° contact angle carries more thrust and less speed than a 15°: the same 7217 envelope at 15° runs 14,300 rpm on oil-air and carries 107.0 kN radially, so the 25° execution trades radial capacity and speed for axial stiffness.

Cage and temperature

Cage Material: Laminated phenolic resin. Cage Type: Outer-ring guided. Maximum Operating Temperature: 120 °C, the limit set by the phenolic cage.

Preload and stiffness

Preload: Light. Axial Preload: 1,080 N for the mounted pair. Axial Stiffness: 283 N/µm. The 25° angle is why the stiffness figure is more than double the 15° equivalent at the same preload grade. RHP publishes exactly four preload grades: extra light, light, medium and heavy.

Mounting data

Bore Type: Straight. Closure Type: Open. Minimum Shaft Abutment Diameter: 95 mm. Maximum Housing Abutment Diameter: 140 mm. Maximum Outer Ring Abutment Diameter: 144 mm. Chamfer r min: 2.5 mm. Chamfer r1 min: 1.0 mm. Effective Load Centre a: 41.4 mm. Internal Volume: 78.5 cm³. Pitch Circle Diameter Of Lubrication Jets: 109.8 mm. The rings are universally faced, so the pair mounts back-to-back or face-to-face without altering the preload value.

Quantity and configuration

Unit Quantity: 2 Pcs. Arrangement: DU, a universally matched pair. Item Weight: 3.564 kg (7.86 lb) for the pair, 1.782 kg (3.93 lb) each.

Interchange guidance

Cross-references on the same envelope, angle and preload: Fafnir 3MM217WI-DUL, FAG B7217-E-T-P4S-DUL, NSK 7217A5TYDULP4, SKF 7217 ACD/P4ADGA and GMN S6217 E TA P4 D UL. The designation is also written 7217ETDULP4, 7217 E T DUL P4, 7217X3TDUEP7 and B7217ETPAP4UL. A 7217 at a 15° contact angle shares this 85 x 150 x 28 mm envelope but carries different ratings and speeds, so it is a related size rather than a substitution.