RHP7204CTDULP4Super Precision Angular Contact Ball Bearing Matched Pair 20x47x14 mm 15° ABEC 7 Light Preload

Product Description

What this part is:

A duplex-ground matched pair of RHP 7204C single-row super-precision angular contact ball bearings. Bore: 20 mm. Outside Diameter: 47 mm. Overall Width: 14 mm per bearing. Total Width: 28 mm for the clamped pair. Contact Angle: 15°. Precision Class: P4, ISO Class 4, ABEC 7, RHP class code EP7. Precision Rating: ABEC 7. Cage Material: laminated phenolic resin. Cage Type: machined, outer ring guided. Closure Type: open on both faces. Bore Type: straight. Rolling Elements: carbon chrome bearing steel balls. Bearing Material: carbon chrome bearing steel to BS970 534A99/535A99 or SAE 52100. Series: RHP 72, ISO dimension series 02. Number Of Rows: 1 per bearing. Design Units: metric. Snap ring included: No.

Decoding the designation:

Type 7: single-row angular contact ball bearing. Dimension series 2: ISO series 02. Bore code 04: 20 mm bore. Contact angle C: 15°. Cage T: machined laminated phenolic resin, outer ring guided. Grouping DU: matched duplex pair, universal face control. Preload L: light. Precision grade P4: ISO Class 4, ABEC 7, RHP class code EP7. The carton cross-reference B7204X2TADULEP7 carries the same bearing in the RHP B-series form, with X2 for the 15° angle and EP7 for the ABEC 7 class.

Load ratings and speed:

Dynamic Load Rating: 14.6 kN, 14,600 N, per single bearing. Static Load Rating: 8.05 kN, 8,050 N, per single bearing. Limiting Speed: 50,700 rpm oil/air; 31,300 rpm grease. Those are the catalogue figures for a single bearing under a spring preload with the inner ring rotating. Mounted as a back-to-back pair at light preload the figures become 40,500 rpm oil/air and 25,000 rpm grease. Lubricant: oil/air or grease. Maximum Operating Temperature: 120 °C.

What these specs mean in practice:

Contact Angle: 15°, the speed-biased angle of the two the range publishes. A 15° pair reaches a higher limiting speed than a 25° pair of the same envelope and carries less axial load and less axial stiffness.

Axial Preload, light grade, as a paired set: 69 N. Axial Stiffness, light grade, as a paired set: 30 N per micrometre. Preload removes internal play, fixes the contact angle and makes axial position and runout repeatable. The L grade adds the least friction heat of the four grades. The bearing is preload-set at manufacture rather than clearance-set.

P4 holds bore, outside diameter, width and running accuracy to single-digit micron limits. Radial runout of the assembled inner ring, Kia: 2.5 µm. Radial runout of the assembled outer ring, Kea: 5 µm. Reference face runout with bore, Sd: 4 µm. Outer diameter runout with reference face, SD: 4 µm. The 72 section is the heaviest of the three RHP super-precision sections at this bore, and carries a higher load rating than the 70 and 719 builds on the same 20 mm shaft.

Quantity and configuration:

Unit Quantity: 2 Pcs, supplied as one matched duplex pair, duplex ground as a set. Arrangement / Configuration: matched duplex pair (DU), universal face control. Universal face control means the inner and outer rings are the same width and the face relief on both sides is set so the pair mounts back-to-back or face-to-face at the same preload, and shares load equally in tandem. Each bearing on its own takes thrust in one direction; back-to-back or face-to-face the pair takes thrust in both directions, and in tandem it takes a larger load in one direction only.

Mounting data:

Inner ring abutment diameter, d1 min: 26 mm. Outer ring abutment diameters: D1 max 41 mm, D2 max 42 mm. Chamfer dimensions: r min 1.0 mm, r1 min 0.6 mm. Effective Load Centre (a): 11.5 mm. Internal free volume: 4.7 cm³. PCD of lubrication jets: 30.5 mm. Item weight: 0.104 kg (0.229 lb) per bearing.

Interchange guidance:

B7204X2TADULEP7 is the RHP B-series form of this bearing, and 2MM204WI is the Fafnir-scheme carton number carried on the same part. NSK 7204CTRDULP4 is the current NSK-RHP catalogue designation. Bearings in this 20 x 47 x 14 mm size that differ in contact angle, preload grade or tolerance class — 7204A5 at 25°, the medium and heavy preload sets, and P3 or P2 class variants — are related sizes. A single universally faced 7204CTRSU is a separate item with its own face grinding.