RHP7020CTDUHP4Super Precision Angular Contact Ball Bearing – Straight Bore, 100 mm Bore, 150 mm OD, 24 mm Width, 15° Contact Angle, P4 / ABEC 7, Heavy Preload, Universally Matchable

Product Description

What this part is

RHP 7020CTDUHP4 super precision angular contact ball bearing in the ISO 10 dimension series. Bore 100 mm, outside diameter 150 mm, width 24 mm. Rings and balls are carbon chrome bearing steel to SAE 52100, through hardened and heat treated for dimensional stability.

Decoding the designation

In the RHP scheme: 7 is a single row angular contact ball bearing, 0 the ISO 10 dimension series, 20 a 100 mm bore code, C a 15° contact angle, T an outer-ring-guided laminated phenolic cage, DU a duplex universal pair, H heavy preload and P4 the precision grade. P4 is ISO Class 4, ABEC 7 and British Standard BS292 grade EP7. The carton also carries the Fafnir designation 2MM9120WICRDUH, in which 2MM denotes the same 15° contact angle, CR the phenolic outer-land-riding cage and the 9100WI series maps to the ISO 70 series, so 9120 is a 7020.

What these specs mean in practice

A 15° contact angle favours speed and radial stiffness; a 25° bearing in the same envelope carries more thrust and runs slower. Basic dynamic radial load rating is 75.5 kN and basic static radial load rating is 77.0 kN. Limiting speed is 13 400 rev/min on oil/air lubrication and 8 400 rev/min on grease for a single bearing under spring preload; a heavy-preloaded back-to-back pair derates by a factor of 0.40, the steepest of the four preload grades, and a face-to-face pair by a further 50 percent. That speed cost is what heavy preload buys stiffness with: a heavy-preloaded pair develops 2 550 N of axial preload at an axial stiffness of 264 N/µm, against 127 N/µm for the light grade. The laminated phenolic cage is rated to a maximum operating temperature of 120 °C.

Quantity and configuration

One bearing. The -1/2PR suffix denotes one half of a DUH duplex universal heavy-preload pair. Universal face control means the inner and outer rings are the same width and the faces are ground at manufacture to the heavy preload value, so two bearings of this designation clamp up back-to-back or face-to-face to that preload without custom spacers, or run in tandem sharing load equally. The matching half is a second 7020CTDUHP4.

Fitting notes

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 diameter; the V also indicates the direction of the contact angle, and aligning the marks minimises assembled runout. Shaft abutment diameter is 109 mm and the housing abutment runs 141 mm minimum to 144 mm maximum. Corner radii are 1.5 mm on the bore and 1.0 mm on the outside diameter. Effective load centre is 28.7 mm. Internal free volume is 53.4 cm³ and the lubrication jet pitch circle is 118.6 mm. At heavy preload the running temperature is more sensitive to lubricant quantity, so oil/air metering or a grease fill of 20 to 30 percent of internal volume applies. A light interference fit on the shaft with a transition fit in the housing suits a locating position with a rotating inner ring.

Interchange guidance

Fafnir 2MM9120WICRDUH is the carton-printed equivalent of this exact execution. SKF 7020 CDGC/P4A matches on envelope, 15° contact angle, phenolic cage, P4A class and heavy preload, the DGC suffix being SKF’s heavy preload grade. FAG B7020-C-T-P4S-UH matches on envelope, 15° angle, laminate phenolic cage and universal heavy preload but is built to the tighter P4S class, so it is a related size on precision grade. The 7020A5 executions run a 25° contact angle in the same envelope and are a related size rather than an interchange, as are the EL, L and M preload grades.