RHP71918CVDUJ74Angular Contact Ball Bearing – Straight Bore, 90 mm ID, 125 mm OD, 18 mm Width, Open, 15° Contact Angle, Light Preload, Matched Duplex Pair

Product Description

What this part is

RHP 71918CVDUJ74 single-row angular contact ball bearing, catalogue designation 7918CTRDULP4. Bore: 90 mm. Outside Diameter: 125 mm. Width: 18 mm. Contact Angle: 15°. Number Of Rows: 1. Bore Type: Straight. Closure Type: Open. Rolling Elements: chrome steel balls. Bearing Material: carbon chrome bearing steel to BS970 534A99 / 535A99, equivalent to SAE 52100, through hardened and stabilised.

Decoding the designation

Series: 7900, ISO dimension series 19. Bore code 18 gives a 90 mm bore. Contact Angle: 15°. Cage Material: laminated phenolic resin. Cage Type: outer-ring guided. Arrangement: DU, a paired unit. Preload: Light. Precision Class: P4. The number is also written 71918-C-V-DU-J74, 7918CTRDULP4, 7918 C T DUL P4 and 71918C.

Load ratings and speeds

Dynamic Load Rating: 41.5 kN. Static Load Rating: 46.0 kN. Limiting Speed: 15,400 rpm with oil-air lubrication and 9,500 rpm with grease. The two speed figures differ because oil-air carries heat out of the bearing and continuously replenishes the film, while grease lubricates without cooling. Mounted as a light-preload back-to-back pair the limiting speed carries a factor of 0.80; face-to-face mounting halves it again.

What these specs mean in practice

A 15° contact angle favours speed and radial stiffness over thrust capacity, which is what a machine tool spindle wants. Axial Preload: 290 N as a light-preload pair. Axial Stiffness: 102 N per micron. Effective Load Centre: 23.4 mm. Lubricant: oil or grease. Maximum Operating Temperature: 120°C, set by the laminated phenolic resin cage. A phenolic cage is light, self-lubricating and quiet, and it runs guided on the outer ring land so the cage is stabilised by the slower-moving ring.

Precision and running accuracy

Precision Class: P4. Precision Rating: ABEC 7, ISO 492 Class 4, BS292 EP7. Deviation of mean bore diameter: 0 to minus 6 microns. Deviation of mean outside diameter: 0 to minus 9 microns. Radial runout of the assembled inner ring: 5 microns maximum. Radial runout of the assembled outer ring: 7 microns maximum. The high point of radial runout is marked by a burnished spot on the inner ring face and by a V line on the outer ring outside diameter, and the V also indicates the direction of the contact angle.

Mounting data

Shaft abutment diameter d1: 97 mm minimum. Housing abutment diameter D1: 118 mm maximum. Outer ring abutment diameter D2: 120 mm maximum. Bearing fillet radius r: 1.5 mm minimum. Inner fillet radius r1: 0.6 mm minimum. Internal Volume: 25.6 cubic centimetres. Lubrication jet pitch circle diameter: 102.8 mm. Mass: 0.559 kg per bearing.

Quantity and configuration

Unit Quantity: 2 Pcs. A universally faced matched duplex pair. Universal face control means the inner and outer rings are the same width and the face relationship is ground at manufacture to give the light preload, so the pair mounts back-to-back or face-to-face at the same preload value and shares load equally in tandem. No custom spacers are needed to set preload.

Interchange guidance

NSK 7918CTRDULP4 is the same bearing under its NSK catalogue number. FAG B71918-C-T-P4S-DUL and Fafnir 2MM9318WI CR DUL match the 15° light-preload duplex execution. SKF 71918 CD/P4ADGA is the 15° pair at extra light preload. Harmonization Code: 8482.10.50.68.