RHPSuper Precision Angular Contact Ball Bearing 45 x 75 x 16 mm, 15° Contact Angle, Light Preload, Universally Ground Single, Machined Phenolic Cage, P3 Accuracy

Product Description

What this part is

A single-row super-precision angular contact ball bearing from RHP’s machine tool spindle range. Bore: 45 mm. Outside Diameter: 75 mm. Overall Width: 16 mm. Contact Angle: 15°. Preload: light (L). Cage Material: laminated phenolic resin. Cage Type: machined, outer-ring centred. Precision Class: RHP P3. Series: 70xx, ISO dimension series 10. Number Of Rows: 1. Rolling Elements: steel balls. Bore Type: straight. Closure Type: open. Unit Quantity: 1 Pc. This is a spindle bearing: grinding and milling heads, high-speed motorised spindles, precision gearboxes, rotary tables and test rigs, where running accuracy, stiffness and thermal behaviour matter more than raw load capacity. The bearing is preload-set at manufacture rather than clearance-set.

Decoding the designation

The carton reads 7009X2TAULEP3 and the outer ring is engraved 7009X2 TAU EP3. This is RHP’s B-series designation style, in which the construction code sits ahead of the grouping code. 7: single-row angular contact ball bearing. 0: RHP dimension series 0, which is ISO series 10, the 70xx tables. 09: bore code, and from code 04 upwards the code × 5 gives the bore, so 45 mm. X2: 15° contact angle. TA: one-piece machined laminated phenolic cage, outer-ring centred. U: universal face control — inner and outer rings the same width, face relationships pre-adjusted at manufacture, so the bearing mounts back-to-back, face-to-face or in tandem at the catalogue preload. L: light preload, RHP’s ladder being EL extra light, L light, M medium, H heavy. EP3: BS292 form of RHP precision grade P3.

What these specs mean in practice

The 15° contact angle is the low-angle option in this range, the alternative being 25°. A shallower angle trades axial load capacity and axial stiffness for speed and lower heat generation, which is why 15° is the usual choice for high-speed spindles and 25° the usual choice where thrust dominates. The published figures for this size make the trade explicit: the 15° version is rated Cr 24,400 N and runs to 30,500 rpm on oil/air, while the 25° equivalent 7009A5TRSU is rated Cr 23,100 N and 26,800 rpm.

Preload removes internal clearance so the balls cannot skid, which is what protects the raceways at speed, and every increment of preload costs speed. RHP’s published limiting-speed factors for a back-to-back pair are 0.85 extra light, 0.80 light, 0.60 medium, 0.40 heavy. Light over medium therefore buys roughly a third more speed capability and gives up axial stiffness: 58 N/µm per light-preloaded pair against 85 N/µm medium.

The laminated phenolic resin cage is light, self-lubricating and outer-ring centred, which suits high speed. Maximum recommended operating temperature for phenolic-caged RHP super-precision bearings is 120°C, and the cage sets that ceiling rather than the steel.

Published ratings and mounting data

From the RHP super-precision catalogue, Table 9, ISO series 10, row 7009. Bore d: 45 mm. Outside Diameter D: 75 mm. Width B: 16 mm. Contact Angle: 15°. Dynamic Load Rating Cr: 24,400 N. Static Load Rating C0r: 19,300 N. Limiting Speed: 30,500 rpm oil/air and 18,800 rpm grease, single bearing. Axial Preload, light, as a matched pair: 150 N. Axial Stiffness, light, as a matched pair: 58 N/µm. Effective Load Centre a: 16.0 mm. Shaft Abutment Diameter d1 min: 51 mm. Housing Abutment Diameter D1 max: 69 mm. Housing Abutment Diameter D2 max: 70 mm. Chamfer r min: 1.0 mm. Chamfer r1 min: 0.6 mm. Internal Free Volume: 11.2 cm³. Lubrication Jet Pitch Circle Diameter dT: 55.6 mm. Item Weight: 0.238 kg. Bearing Material: through-hardened carbon chrome bearing steel to BS970 534A99/535A99, equivalent to SAE 52100. Max Temperature: 120°C.

Quantity and configuration

Unit Quantity: 1 Pc — one single universally ground bearing. Angular contact bearings of this type take thrust in one direction, so they run as opposed pairs or larger sets in service. Universal face control is what makes a single unit useful: any two of these bearings taken from stock produce the correct light preload when clamped together back-to-back or face-to-face, and share load equally in tandem, with catalogue-standard spacing. The Timken/Fafnir 2MM9109WI CR DUL cross-reference is a duplex-pair designation for the same envelope and is carried here as a search term.

Mounting data

Recommended shaft fit for P3/P4 at 45 mm: limits +3/-2 µm, mean interference about 3T, with a rotating inner ring and a load line constant in direction. Recommended housing fit for a locating bearing at this diameter: limits +5/0 µm, mean clearance about 5C; for a sliding position, +7/+2 µm. Out-of-round and cylindricity limits on shaft and housing: ISO grade IT2 and IT3 for P4, tightening to IT1 for P3 and P2 work. Limiting-speed factors at light preload: back-to-back pair 0.80 of the single-bearing figure, a set of three 0.65, a set of four 0.60; face-to-face mounting reduces the result by a further 50 %; spring-loaded tandem pairs take 0.95. Oil/air guide delivery rate: V = 0.15 × d × B mm³/hour at normal speed. Grease fill: 30 % of internal free volume at low to medium speed, 20 % at higher speed, 10–15 % for very high speed spindles. The high point of radial runout is marked by a small circle or burnished spot on the inner ring face and by a V line on the outer ring outside diameter; the V line also indicates the direction of the contact angle.

Interchange guidance

In RHP’s current designation style this bearing is a 7009CTRSUL at P3 grade: series 70, bore code 09, C for 15°, TR for the outer-ring-guided phenolic cage, SU for single universal, L for light preload. The 7009C-T-SUL-P4 and 7009CTSULP4 forms describe the same envelope, contact angle, cage and preload at P4 grade. The FAG/Schaeffler equivalent is B7009-C-T-P4S-UL, the SKF equivalent 7009 CD/P4A, and the NSK equivalent 7009CTRSULP4. The Timken/Fafnir equivalent is the 2MM9109WI CR family, where 2MM denotes the 15° contact angle and CR the phenolic outer-land-riding cage. When substituting across brands, three things decide interchange: the contact angle letter, because the same-looking suffix means different angles in different schemes; the preload letter, because a light-preload bearing paired with a medium-preload one loses the matching; and the grade, because P4 and P3 are dimensionally interchangeable but differ in runout. RHP is part of the NSK group and RHP-branded super-precision product has been superseded by the corresponding NSK range, so RHP-marked stock of this designation is legacy inventory.