RHP7206ETDUMP4Super Precision Angular Contact Ball Bearing 30x62x16 mm, 25° Contact Angle, ABEC 7, Machined Phenolic Cage, Universal Duplex Medium Preload — Matched Pair

Product Description

What this part is

RHP 7206ETDUMP4 matched duplex pair of single-row super-precision angular contact ball bearings for high-speed spindle work. Bore: 30 mm. Outside Diameter: 62 mm. Overall Width: 16 mm per bearing. Total Width: 32 mm for the pair. Contact Angle: 25°. Precision Class: P4 / ABEC 7 / BS292 EP7 / ISO 492 Class 4. Cage Material: laminated phenolic resin. Cage Type: machined, outer-ring guided. Bearing Material: through-hardened chrome bearing steel. Bore Type: Straight. Number Of Rows: 1 per bearing. Rolling Elements: Ball. Closure Type: Open. Series: 72, ISO dimension series 02. Unit Quantity: 2 Pcs.

Published ratings

Dynamic Load Rating Cr: 22.1 kN (22 100 N) per bearing. Static Load Rating C0r: 14.1 kN (14 100 N) per bearing. Limiting Speed: 34 700 rpm on oil/air lubrication and 21 400 rpm on grease. Preload: medium (M), 440 N axial per pair. Axial Stiffness: 147 N/µm per pair. Lubricant: grease or oil. Mass: 0.194 kg per bearing (0.43 lb). Internal Clearance: the pair is preload-set at manufacture rather than clearance-set.

Decoding the designation

7206: single-row angular contact ball bearing, ISO dimension series 02, bore code 06 for a 30 mm bore. E: 25° contact angle in the RHP scheme. T: machined laminated phenolic resin cage, outer-ring guided. DU: duplex universal, a matched pair of universally faced bearings with the preload set at manufacture. M: medium preload. P4: ABEC 7 precision, which buys tighter running accuracy, lower vibration and closer shaft location.

What these specs mean in practice

The 25° contact angle is the choice for a spindle that sees real thrust. Against the 15° build of the same envelope it gives higher axial stiffness and thrust capacity and gives up top speed: the 15° 7206 runs to 39 200 rpm on oil/air where this 25° execution runs to 34 700 rpm. Medium preload sits one step above light, buying stiffness and closer shaft location at the cost of running temperature and speed headroom. RHP derates the limiting speed of a back-to-back pair by a factor of 0.60 at medium preload, against 0.80 at light; a face-to-face arrangement takes a further 50 per cent. The machined phenolic cage is light and quiet, tolerates marginal lubrication far better than steel, and is what makes those speeds available.

Quantity and configuration

Unit Quantity: 2 Pcs — one complete matched duplex pair, supplied in two factory-sealed RHP cartons each labelled 7206ETDUMP4. The load ratings above are the catalogue figures for a single bearing of this designation. Arrangement / Configuration: DU, universally faced, so the pair mounts back-to-back (DB), face-to-face (DF) or in tandem (DT) at the same catalogue preload, with no spacers or shims. The preload was established across this specific pair, so the two halves belong together and stay oriented as ground. Carton markings reproduced as printed: RR, 5 D:T / d:T, 09P96, MADE IN ENGLAND.

Mounting data

Effective load centre a: 18.7 mm. Chamfer r min: 1.0 mm. Chamfer r1 min: 0.6 mm. Shaft abutment diameter d1 min: 36 mm. Housing abutment diameter D1 max: 56 mm. Second housing abutment diameter D2 max: 57 mm. Internal free volume: 8.8 cm³. Pitch circle diameter for lubrication jets: 42.4 mm. Universal facing sets the preload at manufacture, so back-to-back and face-to-face mounting both deliver the catalogue figure and a tandem pair shares load equally.

Cross-references

The current NSK number is 7206A5TRDUMP4. NSK acquired the RHP group in the early 1990s and traded as NSK-RHP until the RHP name reverted to NSK in November 2000; RHP super-precision bearings are still made at the former Ransome & Marles works in Newark. Other 25° cross-references at 30 x 62 x 16 mm: FAG B7206-E-T-P4S-DUM, Fafnir 3MM206WI DUM and SKF 7206 ACD/P4A (specify the matching preload class). Internal designs and load ratings differ between makers. Related builds on the same envelope: 7206ETDULP4 (light preload), 7206ETDUHP4 (heavy preload), 7206ETSUMP4 (single universally ground). 7206CTDUMP4 is the 15° build on the same envelope — a related size, with a higher speed ceiling and lower thrust capacity.