Spherical Roller Bearing

A spherical roller bearing has two rows of rollers, a common sphered raceway in the outer ring and two inner ring raceways set at an angle to the bearing axis [1]. The inner ring and rollers can tilt inside the outer ring, so it is also called a self-aligning roller bearing. It carries heavy radial load and axial load in both directions [1]. FULI is a spherical roller bearing manufacturer and supplies eleven series, from 21300 to 24800, from our factory in Linqing, Shandong; our bearing manufacturer page shows the other types we make. Below: how the series differ, which bore type to order and where these bearings are used.

Spherical roller bearing series and size chart

In a spherical roller bearing number, the first digit 2 marks the bearing type, the next two digits give the dimension series (13, 22, 23, 30, 31, 32, 38, 39, 40, 41 or 48 on this site), and the last two digits are the bore code [1]. Dimensions follow ISO 15 [1], so the same number has the same bore d, outside diameter D and width B at any maker.

The cage is usually named in a suffix after the number, and it does not change d, D or B. Suffixes differ by maker, but CA and MB usually mark a machined brass cage, while E and CC usually mark pressed steel window-type cages. A machined brass cage is the common choice for heavy or shock loads and higher operating temperatures; a pressed steel cage is lighter and suits general machinery under normal loads.

Series	Bore d (mm)	Outside diameter D (mm)	Width B (mm)	Sizes on this site
21300	25 to 100	62 to 215	17 to 47	16
22200	25 to 360	52 to 650	18 to 170	33
22300	40 to 400	90 to 820	33 to 243	28
23000	110 to 500	170 to 720	45 to 167	25
23100	100 to 500	165 to 830	52 to 264	26
23200	90 to 500	160 to 920	52.4 to 336	27
23800	300 to 500	380 to 620	60 to 90	3
23900	180 to 500	250 to 670	52 to 128	18
24000	65 to 500	100 to 720	35 to 218	28
24100	100 to 500	165 to 830	65 to 325	26
24800	460	580	118	1

For the same bore, a 23000 series bearing has a smaller outside diameter than a 22200 series bearing, and a 22300 bearing is larger and wider, for heavier load at the same bore. The 23200 series keeps the 22200 outside diameter but is wider: 23220 is 100 x 180 x 60.3 mm against 46 mm for 22220. The full size list is in the table at the top of this page. A few sizes as examples:

• 22208 bearing: 40 x 80 x 23 mm
• 22212 bearing: 60 x 110 x 28 mm
• 22220 bearing: 100 x 180 x 46 mm
• 23022 bearing: 110 x 170 x 45 mm

Misalignment and internal clearance

Because the outer ring raceway is part of a sphere, the bearing accepts angular misalignment between shaft and housing [1]. For the 22200 and 23000 series, one maker’s catalogue gives a permissible misalignment of 2°, for light to normal loads with the misalignment in a constant position [1]. Where the misalignment changes all the time, as in vibrating screens, the same catalogue limits it to a few tenths of a degree [1].

Radial internal clearance is a C-class value. FULI spherical roller bearings are C0 (normal) as standard, with C3 on request. A K bearing is mounted with an interference fit, and driving it up on the seat or sleeve reduces the radial internal clearance [1]. State the clearance class you need in the inquiry. The bearing internal clearance guide explains how to choose.

Bore type: cylindrical, tapered or with adapter sleeve

A spherical roller bearing comes with one of two bore types. Most sizes are made in both [1][2].

Bore type	Designation	How it is mounted
Cylindrical	No suffix, e.g. 22208	Press fit on a cylindrical shaft seat
Tapered, 1:12	Suffix K, e.g. 22208 K	On a tapered shaft seat, or with a sleeve
Tapered with adapter sleeve	Bearing with K plus a sleeve, e.g. 22208 K on H 308	On a plain or stepped shaft; the sleeve clamps on

A tapered bore bearing can be mounted with an adapter sleeve on a plain or stepped shaft, or with a withdrawal sleeve on a stepped one [1]. The sleeve has a smaller bore than the bearing: in one catalogue, 22208 K on an H 308 adapter sleeve fits a 35 mm shaft [1]. Check the shaft diameter against the sleeve, not against the bearing bore.

The models on this site are listed with a cylindrical bore. For the tapered bore version, add K to the number in your inquiry and we will confirm availability with the quote. Brand suffixes for the oil groove and holes differ by maker; the spherical roller bearing cross reference lists 13 common sizes with the SKF, NSK, NTN, Koyo, NACHI and FAG numbers.

SKF, NSK, NTN, Koyo, NACHI and FAG are trademarks of their respective owners. FULI is not affiliated with, authorized by or endorsed by any of these companies. Part numbers are shown for interchange reference only. FULI dimensions, load ratings and speeds come from the FULI catalog.

Advantages of spherical roller bearings

Among the main bearing types, this design combines high load capacity with self-alignment. Compared to other types:

• A needle or cylinder-type bearing carries little or no thrust and needs the housings in line. This design takes thrust both ways and keeps running under deflection.
• A tapered roller bearing takes more thrust and runs faster, but it must be adjusted on mounting and tolerates almost no tilt.
• A double-row ball design with a sphered outer race aligns the same way, but its balls make point contact. Its barrel-shaped elements make line contact, so load capacities are much higher for the same size.

Mounting and dismounting

A plain-bore bearing goes onto its seat with an interference fit. Small sizes can be pressed on; larger ones are warmed in an induction heater and slid on, never heated with an open flame. A K bearing is driven up its seat or sleeve with a lock nut or hydraulic nut until the internal clearance has dropped by the amount the maker gives for that size [1]. Measure it with feeler gauges before and after.

Adapter sleeves work on a plain shaft with a wide diameter tolerance, such as h9 [1], so it needs no grinding. To dismount, loosen the nut a few turns and drive the sleeve back; a withdrawal sleeve is pulled out with its own nut. On large sizes, oil injected into the fit makes both jobs easier [1].

Lubrication, load ratings and service life

Most of these bearings run on grease. An annular groove with three holes in the outer race, marked W33 or built in depending on the maker, lets fresh grease reach the space between the rows. At high speed or high temperature, oil bath or circulating oil is used instead. See grease choice and intervals.

Each model page lists the dynamic rating Cr and static rating C0r from FULI’s catalog. Cr sets the rating life under rotating load; C0r matters for shock and slow turning. Most bearing failures in heavy plant come from dirt, poor greasing or a wrong fit, not from fatigue. On screens and large fans, condition monitoring by vibration and temperature finds damage early and avoids unplanned downtime.

Typical applications

These bearings are used where load is heavy and the shaft cannot be held in perfect line:

• Crushers and vibrating screens. Bearings made for vibrating machinery are a separate design with C4 clearance [1][2], and one catalogue lists them in the 22300 series [1]. The standard 22300 sizes on this site are not that design; send the screen bearing designation and we will confirm it with the quote. See vibrating screen applications.
• Conveyor drums and pulleys.
• Large fans and blowers, when ball bearings do not give enough life. See fan and blower bearings.
• Gearboxes, and paper and textile machinery.
• Wind turbine main shafts and other large rotor shafts in power generation.

If the load is mainly axial in one direction, or the shaft is short and well aligned, a tapered roller bearing may suit better. The ball bearing vs roller bearing guide compares the types.

Specifications FULI supplies

Item	FULI specification
Series	21300 to 24800, eleven series (bores 25 to 500 mm)
Design	Open, double row
Bore	Cylindrical; tapered (K) on request, confirmed with the quote
Material	GCr15 chrome bearing steel, rings and rollers
Precision	P0 standard; P6 on request
Radial clearance	C0 standard; C3 on request
Load ratings	Cr, C0r, speeds and weight from FULI’s catalog on the model pages

To get a quotation, send the bearing number with any suffix (for example 22212 or 22212 K C3), the quantity per size and the destination port to sales@fuli-bearings.com or use the request a quote form.

Sources

1. https://www.skf.com/binaries/pub12/Images/0901d196802809de-Rolling-bearings---17000_1-EN_tcm_12-121486.pdf
2. https://www.timken.com/wp-content/uploads/2016/10/Timken-Engineering-Manual_10424.pdf