RHP7011CTSUMP2Super Precision Angular Contact Ball Bearing – Straight Bore, 55 mm ID, 90 mm OD, 18 mm Width, Open, 15° Contact Angle, Medium Preload, ABEC 9 / P2

Product Description

What this part is:

RHP 7011CTSUMP2 super-precision single-row angular contact ball bearing. Bore: 55 mm. Outside Diameter: 90 mm. Width: 18 mm. Contact Angle: 15°. Precision Class: P2, equivalent to ABEC 9 and ISO Class 2. Dynamic Load Rating: 34 kN. Static Load Rating: 28.6 kN. Cage Material: Laminated phenolic resin. Cage Type: Outer ring guided. Bore Type: Straight. Closure Type: Open. Rolling Elements: Steel balls. Number Of Rows: 1. Series: 7000, ISO dimension series 10. Bearing Material: Through-hardened carbon chrome bearing steel to SAE52100.

Decoding the designation:

7011 is the type and size: single-row angular contact, ISO dimension series 10, bore code 11 for a 55 mm bore. C sets the contact angle at 15°. T is the outer-ring-guided laminated phenolic resin cage. M sets medium preload. P2 is the precision grade, the tightest of the three RHP super-precision grades and the equivalent of the British Standard EP9 marking carried on the carton. Searchable variants of the number: 7011C, 7011-C-T-SUM-P2, 7011-C-T-DUM-P2, 7011 CT SUM P2, B7011X2TADUMEP9, 2MMV9111WI CR DUM.

What these specs mean in practice:

Limiting Speed: 25,000 r/min on oil-air lubrication and 15,400 r/min on grease. The two figures are the published pair for a single bearing under light external load, and the gap between them is why the lubrication method is chosen before the bearing is. Preload: Medium, 490 N axial. Axial Stiffness: 102 N/µm. Medium preload raises spindle rigidity over the light grade and lowers the speed a mounted pair will hold. Internal Clearance: N/A, as preload and mounted clearance are set against one another. Lubricant: grease or oil. Maximum operating temperature for a laminated phenolic resin cage is 120 °C. Item weight: 0.375 kg (0.83 lbs).

What P2 accuracy buys:

P2 is the tightest grade in this range. Radial runout of the assembled inner ring: 2.5 µm. Radial runout of the assembled outer ring: 5 µm. Deviation of mean bore diameter: −3.8 µm. Deviation of mean outside diameter: −5 µm. Reference face runout with bore: 1.3 µm. Against P4 in the same size those runout figures are roughly halved, which is what holds a machined surface finish and keeps spindle vibration down at speed. Tighter grades also demand more of the housing: at P2 the recommended shaft fit is a mean 1.9 µm interference against 3 µm at P4.

Mounting dimensions:

Shaft abutment diameter d1: 62 mm minimum. Housing abutment diameter D1: 83 mm maximum. Outer ring abutment D2: 85 mm maximum. Chamfer r: 1.1 mm minimum. Chamfer r1: 0.6 mm minimum. Effective Load Centre a: 18.7 mm. Internal volume: 16.9 cm³, the figure grease quantity is calculated from.

Interchange guidance:

Cross-references: FAG B7011-C-T-P2-UM, NSK 7011CTRSUMP2, Fafnir 2MMV9111WI CR DUM (P4S running accuracy, not P2). FAG and NSK name the 15° phenolic-caged execution at the P2 grade. The 25° 7011A5 has the 55 x 90 x 18 mm dimensions and is a related size rather than a substitution, since angle sets both the thrust capacity and the speed limit.