SNRN311Cylindrical Roller Bearing – Single Row N Design, 55 mm ID, 120 mm OD, 29 mm Width, Separable Plain Outer Ring, Floating, Pressed Steel Cage

Product Description

What this part is

SNR N311 single-row cylindrical roller bearing, N design, floating and separable. Series: N300 (ISO dimension series 03). Bore: 55 mm. Outside Diameter: 120 mm. Width: 29 mm. Bore Type: Straight. Rolling Elements: Cylindrical Roller. Number Of Rows: 1. Internal Clearance: CN.

Decoding the designation

N311 — the ISO N311 size, 55 x 120 x 29 mm. The N design carries both guiding ribs on the inner ring and a plain outer ring.

A12 — SNR order-code token, recorded as a designation variant.

What these specs mean in practice

Dynamic Load Rating: 123 kN. Static Load Rating: 111 kN. Fatigue Limit Load Cu: 13.6 kN. Limiting Speed: 7,000 r/min on oil, 5,900 r/min on grease. Internal Clearance: CN. Cage Material: Steel. Cage Type: Pressed. Chamfer rs min: 2 mm. Chamfer r1s min: 2 mm. Mass: 1.42 kg. Upper roller diameter E: 104.5 mm. Under roller diameter F: 70.5 mm. Inner ring flange outside diameter d1: 77.2 mm. Minimum operating temperature: −40 °C. Maximum operating temperature: 120 °C.

Straight rollers on straight raceways give line contact, so a 55 mm bore reaches 123 kN dynamic in a 120 mm envelope, several times what a ball bearing of the same size manages. The N design puts both ribs on the inner ring and leaves the outer ring plain, so the outer ring lifts away for mounting and the shaft is free to grow axially inside it. That makes this the floating position in a two-bearing shaft, with the located bearing at the other end taking the thrust.

Mounting data

Shaft abutment diameter da: 64 mm minimum. Housing abutment diameter Da: 111 mm maximum. Small face shoulder minimum diameter Db: 106 mm. Maximum outer ring guide diameter Dc: 103 mm. Shaft and housing fillet radius ra and r1a: 2 mm. The rings separate, so the inner ring with its rollers and cage can be heated and fitted to the shaft before the plain outer ring goes into the housing.

Quantity and configuration

Unit Quantity: 1 Pc.

Interchange guidance

Cross-references: SKF N 311 ECP, FAG N311-E-XL-TVP2, NSK N311, NTN N311. Searchable variants of the designation: N311, N 311, N-311, N311A, N311A12, N311 A 12. An NU311 is the mirror design on the same envelope, with both ribs on the outer ring and a plain inner ring.