SNR22218EAB33J30Double-Row Self-Aligning Spherical Roller Bearing, 90mm x 160mm x 40mm, Cylindrical Bore, Open With Outer-Ring Lubrication Groove, C3 Clearance

Product Description

What this part is

A double-row spherical roller bearing on a 90 mm bore, 160 mm outside diameter and 40 mm width, in the ISO 22200 series. Two rows of barrel-shaped rollers run against a single spherical (part-sphere) raceway machined into the outer ring. That geometry is the whole point of the design: the inner ring, rollers and cage can swivel bodily inside the outer ring, so the bearing accommodates misalignment between the shaft and the housing.

What self-alignment actually buys you

A cylindrical or tapered roller bearing has line contact along a fixed axis. Tilt the shaft relative to the housing by even a fraction of a degree and the load concentrates on the roller ends, contact stress spikes, and the raceway spalls out early. A spherical roller bearing simply rolls the roller set to a new angle and keeps full-length contact.

That is why this type is specified for long transmission shafts that sag under their own weight, for fabricated or bolted housings where the two bearing seats cannot be bored in one setup and will never be perfectly coaxial, and for vibrating screens, crushers, conveyor pulleys, fans and mill duty where the structure flexes under load. Misalignment on those machines is not a defect to be eliminated, it is a running condition to be designed around, and this bearing is how it is done. The same double-row barrel geometry also gives very high radial capacity and the ability to take axial load in either direction.

Decoding the designation

22218 – ISO 22200 series spherical roller bearing, 90 mm bore, cylindrical (straight) bore.
E – uprated internal design: a heavier roller complement and reinforced internal geometry for higher load capacity within the same envelope.
A – SNR internal design variant. Appears in the NTN-SNR designation as EA, the ULTAGE type E design family.
W33 – annular lubrication groove in the outer ring plus three radial feed holes, allowing grease or oil to be delivered directly into the loaded zone from the housing.
B33 – carried on this carton. Most likely SNR’s own coding for the same outer-ring groove and three-hole lubrication feature as W33; not independently confirmed against NTN-SNR published literature, so it is flagged rather than asserted.
C3 – radial internal clearance greater than the normal group.
J30 – not decoded. No published meaning was found in NTN-SNR literature. Retained in the title and attributes as a search term so buyers holding a carton marked J30 can find this listing.

Correcting the source data

The previous description carried several claims that do not survive checking, and they have been removed rather than repeated:

“Sealed with an open seal” — self-contradictory. A W33 bearing in this series is open: no seals, no shields. It is relubricated through the outer-ring groove, which is precisely why the groove exists. There is no seal to describe.
“Dynamic load rating of 335 kN” — not supported. NTN-SNR’s own eShop publishes a dynamic load rating of 398,000 N for the 22218EAW33 in this envelope. The 335 kN figure could not be corroborated against the manufacturer and has been dropped.
“Precision rating ABEC 1”, “maximum temperature 200 °C” and “limiting speed 3600 rpm” — none verified against NTN-SNR for this designation. Left out. Operating temperature in particular depends on the cage material and the lubricant, neither of which is published here.
“Manufactured in Italy” — unsupported. SNR is a French company, now NTN-SNR. No country of manufacture is claimed for this item.

What the old text got right, and what is retained, is that this is a spherical roller bearing and not a ball bearing.

What these specs mean in practice

C3 clearance is the specification most often got wrong, and it fails in both directions. Internal clearance shrinks once the bearing is mounted: an interference fit on the shaft expands the inner ring, and heat in service expands the inner ring faster than the outer. C3 starts with more room than normal clearance so that after fitting and after warm-up there is still a working film and a properly sized load zone. Fit a normal-clearance bearing where the design called for C3, or run it hotter than intended, and the bearing preloads itself, temperature runs away and it fails quickly. Go the other way and fit C3 where normal was specified in a lightly loaded, cool application and you get excess running clearance, roller skidding, noise and vibration. C3 is a design decision made against the shaft fit and the thermal gradient — match what came out of the machine.

The W33 groove is what makes this bearing serviceable in place. With a grease line into the housing you can relubricate on a schedule without stripping the machine, and fresh grease enters at the raceway rather than having to migrate there. On a screen or a crusher that is the difference between a planned lubrication round and an unplanned strip-down.

Published ratings and mounting data

Bore d: 90 mm (cylindrical bore)
Outside diameter D: 160 mm
Width B: 40 mm
Rows: 2
Rolling elements: barrel (spherical) rollers
Raceway: spherical outer raceway, self-aligning
Closure: open, no seals or shields
Relubrication: outer-ring annular groove with three radial feed holes (W33)
Internal clearance: C3, greater than normal
Dynamic load rating: 398,000 N, published by NTN-SNR for 22218EAW33 in this envelope
Static load rating: not published in the sources checked — no figure asserted
Limiting speed: not published in the sources checked
Cage type and material: not published for this designation

The static rating is deliberately blank. On a bearing of this size the static figure would normally exceed the dynamic one, but a plausible number is still a made-up number, and a fabricated static rating is exactly the sort of error that gets a bearing selected into an application it cannot survive. Request C0 from NTN-SNR against the exact designation if a calculation depends on it.

Quantity and configuration

Two are recorded on hand. On-hand counts in this catalogue sometimes track lots rather than individual pieces, so confirm the exact piece count before committing to a pair. Note that these bearings are frequently bought in pairs for the two ends of a single shaft, and if so, buying both from the same batch is worth doing.

Fitting notes

Mount by heating the inner ring or with a hydraulic nut; never strike the outer ring to seat the inner. Check residual internal clearance after fitting with feeler gauges across the unloaded roller row if the application is clearance-critical. Align the housing feed hole with the W33 groove so relubrication actually reaches the rollers. Do not use the self-aligning capability as an excuse for careless alignment — it is there to absorb what cannot be engineered out, and misalignment still costs life and heat even within the bearing’s tolerance.

Interchange guidance

SNR is now NTN-SNR; SNR-branded stock and NTN-SNR stock are the same lineage. Numbers to search alongside this one: 22218, 22218E, 22218EA, 22218EAW33, 22218EAW33C3, 22218EAB33, 22218EAB33J30. The equivalent from other manufacturers on the 90 x 160 x 40 mm envelope carries the same 22218 base number with maker-specific suffixes for the internal design and the lubrication groove — confirm the groove, the clearance class and the bore type (cylindrical here, not tapered) match before substituting. A K suffix on any candidate means a tapered bore and will not fit a straight shaft seat.