FAGN311EM1C3Single Row Cylindrical Roller Bearing 55x120x29 mm Non-Locating N Design Brass Cage C3

Product Description

What this part is

A single row cylindrical roller bearing of N design, 55 mm bore, 120 mm outside diameter, 29 mm width, with a machined brass cage and C3 internal clearance. The rollers are line-contact cylinders, giving a much higher radial load rating than a ball bearing of the same envelope.

Decoding the designation

In the FAG scheme N is the design in which the two integral guide ribs sit on the outer ring and the inner ring is plain, without ribs. 3 is the dimension series and 11 the ISO bore code, five times eleven giving the 55 mm bore. E is the reinforced X-life design, with a larger roller complement and increased load rating over the standard version. M1 is a machined brass cage in a specific FAG design variant. C3 is radial internal clearance greater than normal.

Axial location

The N design is a non-locating bearing. With ribs on one ring only, the rings are free to displace axially relative to one another within the bearing, so the design carries radial load and provides no axial location. That freedom is the point: an N or NU bearing takes up shaft thermal growth at the floating end of a two-bearing arrangement while a locating bearing at the other end sets the axial position. The related designs in this family are NJ, which locates in one direction, and NUP, which locates in both.

What these specs mean in practice

Line contact between roller and raceway spreads load over a length rather than a point, so a cylindrical roller carries several times the radial load of a same-size ball bearing and is stiffer under that load. The cost is sensitivity to misalignment, since a skewed roller loads at one end of its length. The 3 series is the medium section, so this is a heavier bearing than a 55 mm N211 and lighter than an N411.

Cage and clearance

A machined brass cage suits high speeds, high temperature and shock loading, and is dimensionally stable under sustained load. C3 clearance is greater than normal, which offsets the loss of internal clearance caused by an interference fit on the shaft and by the inner ring running hotter than the housing.

Quantity and configuration

1 Pc. Straight cylindrical bore. Separable design: the outer ring, with the roller and cage assembly retained by its ribs, comes apart from the plain inner ring. Open on both faces, with no seals, shields, snap ring or outer ring lubrication holes.

Interchange guidance

Other makers’ N311E cylindrical roller bearings at the same clearance and cage class are the interchange. An NU311E is the mirror design — ribs on the inner ring, plain outer — and is also non-locating, so it is functionally equivalent in axial terms but not dimensionally interchangeable in the housing and shaft detail. An NJ311E or NUP311E shares the envelope but locates the shaft axially and is therefore a related size, not a substitution.