RHPSuper Precision Angular Contact Ball Bearing – Straight Bore, 90 mm ID, 160 mm OD, 30 mm Width, Open, 15° Contact Angle, Light Preload, Universally Ground, ABEC 7

Product Description

What this part is

RHP 7218CTDULP4 single-row super-precision angular contact ball bearing, made in England. Bore: 90 mm. Outside Diameter: 160 mm. Overall Width: 30 mm. Contact Angle: 15°. Precision Class: P4, equivalent to ABEC 7 and to BS292 EP7. Number Of Rows: 1. 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 7218-C-T-DUL-P4: 7 is a single-row angular contact ball bearing, 2 is ISO dimension series 02, the bore code 18 gives a 90 mm bore, C is the 15° 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 trailing 1/2PR marks one bearing out of that pair. The carton also carries the B-series form B7218X2TADULEP7, the Fafnir cross 2MM218WI CR DUL and the short form 218HDL.

What these specs mean in practice

Dynamic Load Rating: 123.0 kN. Static Load Rating: 105.0 kN. Limiting Speed, oil-air lubrication: 13,400 rpm. Limiting Speed, grease lubrication: 7,800 rpm. Those are the single-bearing figures under light spring preload. Run as a back-to-back light-preload pair the limiting speeds are multiplied by 0.80, giving 10,720 rpm on oil-air and 6,240 rpm on grease. A 15° contact angle favours speed and radial stiffness where a 25° angle favours thrust capacity.

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: 780 N for a mounted pair. Axial Stiffness: 126 N/µm. Light is the grade RHP selects most often, suiting applications where loads and speeds are not extreme. RHP publishes exactly four preload grades: extra light, light, medium and heavy.

Mounting data

Bore Type: Straight. Closure Type: Open. Minimum Shaft Abutment Diameter: 100 mm. Maximum Housing Abutment Diameter: 150 mm. Maximum Outer Ring Abutment Diameter: 154 mm. Chamfer r min: 2.5 mm. Chamfer r1 min: 1.0 mm. Effective Load Centre a: 31.7 mm. Internal Volume: 95.1 cm³. Pitch Circle Diameter Of Lubrication Jets: 116.7 mm. The rings are universally faced, so the bearing mounts back-to-back or face-to-face against its partner without altering the preload value.

Quantity and configuration

Unit Quantity: 1 Pc. Item Weight: 2.206 kg (4.86 lb). One bearing from a universally matched light-preload pair, carrying the DUL face grinding, so it pairs with another DUL 7218C to make up a set or runs as a universal single.

Interchange guidance

Closest matches at the same size, angle, cage and preload: SKF 7218 CD/P4ADGA, Fafnir 2MM218WI CR DUL and Barden 218HDL. NSK 7218CTYNDULP4 is the same bearing with a polyamide cage. The designation is also written 7218CTDULP4, 7218 C T DUL P4, 7218C and B7218X2TADULEP7. A 7218 at a 25° contact angle shares this 90 x 160 x 30 mm size but carries different ratings and speeds, so it is a related part rather than a substitution.