Types of Bearings

Ball BearingsGenerally speaking, a bearing is a device that is used to enable rotational or linear movement, while reducing friction and handling stress. Resembling wheels, bearings literally enable devices to roll, which reduces the friction between the surface of the bearing and the surface it’s rolling over. It’s significantly easier to move, both in a rotary or linear fashion, when friction is reduced—this also enhances speed and efficiency.


Types of Bearings

There are numerous different kinds of bearings that are designed to handle radial load, thrust load, or some combination of the two. Because different applications require bearings that are designed to handle a specific kind of load and different amounts of weight, the differences between types of bearings concern load type and ability to handle weight.

Ball Bearings
Ball bearings are extremely common because they can handle both radial and thrust loads, but can only handle a small amount of weight. They are found in a wide array of applications, such as roller blades and even hard drives, but are prone to deforming if they are overloaded.

Roller Bearings
Roller bearings are designed to carry heavy loads—the primary roller is a cylinder, which means the load is distributed over a larger area, enabling the bearing to handle larger amounts of weight. This structure, however, means the bearing can handle primarily radial loads, but is not suited to thrust loads. For applications where space is an issue, a needle bearing can be used. Needle bearings work with small diameter cylinders, so they are easier to fit in smaller applications.

Ball Thrust Bearings
These kinds of bearings are designed to handle almost exclusively thrust loads in low-speed low-weight applications. Bar stools, for example, make use of ball thrust bearings to support the seat.

Roller Thrust Bearings
Roller thrust bearings, much like ball thrust bearings, handle thrust loads. The difference, however, lies in the amount of weight the bearing can handle: roller thrust bearings can support significantly larger amounts of thrust load, and are therefore found in car transmissions, where they are used to support helical gears. Gear support in general is a common application for roller thrust bearings.

Tapered Roller Bearings
This style of bearing is designed to handle large radial and thrust loads—as a result of their load versatility, they are found in car hubs due to the extreme amount of both radial and thrust loads that car wheels are expected to carry.

Specialized Bearings
There are, of course, several kinds of bearings that are manufactured for specific applications, such as magnetic bearings and giant roller bearings. Magnetic bearings are found in high-speed devices because it has no moving parts—this stability enables it to support devices that move unconscionably fast. Giant roller bearings are used to move extremely large and heavy loads, such as buildings and large structural components.

BEARING NUMBER CODE REFERENCE

BEARING NUMBER CODE REFERENCE

Interchange – Single Row Ball Bearings

	Description	NSK	SKF	Torr / Faf	FAG	MRC
P/N	Inch	Rxx	Rxx	Sxx	Rxx	Rxx
	Extra small	6xx	6xx	3x	6xx	3x
	Extra light	60xx	60xx	91xxK	60xx	1xxK
	Light	62xx	62xx	2xx	62xx	2xxS
	Medium	63xx	63xx	3xx	63xx	3xxS
	Extra thin section	68xx	618xx	–	618xx	–
	Very thin section	69xx	619xx	93xxK	619xx	–
	Thin section	16xxx	16xxx	–	16xxx	–
	Maximum capacity, light	BL2xx	2xx	2xxW	2xx	2xxM
	Maximum capacity, medium	BL3xx	3xx	3xxW	3xx	3xxM
Suffix	Two seals (contact)	DDU	2RS	PP	2RSR	ZZ
	One seal (contact)	DU	RS	P	RSR	Z
	Two shields	ZZ	2Z	DD	2ZR	FF
	One shield	Z	Z	D	ZR	F
	Snap ring	NR	NR	G	NR	G
	Steel cage	BLANK	J	BLANK	BLANK	BLANK
	Brass Cage	M	M	MBR	M	BRZ
	Heat stabilized 200C	X28	S1	–	S1	–
	Tight clearance	C2	C2	H	C2	Tight
	Normal clearance	BLANK	BLANK	R	BLANK	Normal
	Loose clearance	C3	EM(C3)	P	C3	Loose
	Extra loose clearance	C4	C4	J	C4	Extra Loose
	Electric motor grade	E	QE6	–	–	–

Interchange – Double Row Ball Bearings

	Description	NSK	SKF	Torr / Faf	MRC
P/N	Self-aligning, extra narrow	12xx	12xx	–	–
	Self-aligning, narrow	133xx	13xx	–	–
	Self-aligning, wide	22xx	22xx	–	–
	Self-aligning, extra wide	23xx	23xx	–	–
	Double row, maximum compliment, light	32xx	52xxE	52xxW	52xxM (K)
	Double row, max. compliment, medium	33xx	53xxE	53xxW	53xxM (K)
	Double row, conrad, light	52xx	52xxA	52xxK	52xxC(SBK)
	Double row, conrad, medium	53xx	53xxA	53xxK	53xxC (SB)
Suffix	Two seals	2RS	2RS1	–	–
	Two shields	ZZ	2Z	–	FF
	Snap ring	NR	NR	G	G
	polyamide cage	TNG	TN9	pRB	–
	Steel cage	J	BLANK	BLANK	BLANK
	Tapered bore	K	K	–	–
	Extra capacity	E	E	–	–
	Tight clearance	C2	C2	H	C2
	Normal clearance	BLANK	BLANK	R	BLANK
	Loose clearance	C3	C3	p	C3
	Extra loose clearance	C4	C4	J	C4

Interchange – Angular Contact (ABEC 1 & 3) Ball Bearings

	Description	NSK	SKF	Torr / Faf	FAG	MRC
P/N	Light	72xx	72xx	72xx	72xx	72xx
	Medium	73xx	73xx	73xx	73xx	73xx
	Heavy	74xx	74xx	74xx	74xx	74xx
Suffix	40 deg. contact	B	B	WN	B	pJ
	30 deg. contact	A	–	–	–	BLANK
	25 deg. contact	A5	ACD	–	E	–
	15 deg. contact	C	CD	–	C	R
	Machined brass cage	M	M	MBR	Mp	BRZ
	pressed brass cage	Y	Y	BLANK	Yp	–
	polyamide cage	TY	p	pRC	TVp	BKE
	Steel cage	W	J	–	Jp	BLANK
	Flush ground faces	G	G	BLANK	UO,UA	DU
	petrochemical	BMpC	BECBM	–	–	pumppac*

Glossary – Cylindrical Roller Bearings

• NU style single row – NU style bearings have two machined flanges on the outer ring and no flanges on the inner ring.
• N Style single row – N style bearings have two machined flanges on the inner ring and no flanges on the outer ring, with rollers and cage on the inner ring. Like the NU style, the N has no thrust load carrying capability.
• NJ style single row – NJ style bearings have two machined flanges on the outer ring and a machined flange on one side of the inner ring. The roller and cage assembly is in the outer ring. The integral flange on the inner ring allows this bearing to carry an axial load.
• NF style single row – NF style bearings have two machined flanges on the inner ring and one flange on the outer ring, with roller and cage on the inner ring. Like the NJ bearing, these bearings have some thrust load capability.
• NH style single row – NH style bearings have two machined flanges on the outer ring and a machined flange on one side of the inner ring. A special-design inner ring allows use of a stabilizing ring on the non-flange side. As a result, these bearings can carry axial loads in both directions. The roller and cage assembly is mounted in the outer ring.
• NUP style single row – NUP style bearings are similar to the NJ style and come with a special ring often called a thrust collar. Mounted on the non-flange side of the inner ring, the thrust collar allows the bearing to carry an axial load in both directions. The thrust collar extends out of the bearing on one side, so the dimension across the inner ring is slightly greater than that of the outer ring.
• Double row styles (NN, NNU) – Double Row cylindrical roller bearings are denoted by two N’s within the part number (e.g., NN or NNU). The dimensions for these can be found in the Super Precision section of this catalog and can be ordered with standard precision.
• S-Type – Sealed-Clean Bearings for chain conveyors demonstrate a high efficiency under high temperatures and wet conditions for a longer period with an improved sealing system. These bearings are packed with a quality grease of high thermal resistance and durability.
• Continuous Caster Roller Bearings – These are 2-split bearing units of a highly reliable design and feature a long service life. Cylindrical roller bearings with self-aligning rings having a proper alignment function.
• Four Row Cylindrical Roller Bearings – Are also popular roll neck bearings providing several benefits. First, the inner ring is separable form the outer ring and rollers which allows the inner ring to remain with the roll during grinding processes. This assures precise concentricity and negligible run-out providing for high rolling accuracy. Secondly, this design allows for greater radial load carrying and higher operating speeds. Four row cylindricals must be used in combination with a thrust bearing which is usually a two row taper, angular contact ball bearings, or a deep groove ball bearing depending on the thrust load present.

Interchange – Cylindrical Roller Bearings

	Description	NSK	SKF	FAG
Prefix	Single row, no flanges on outer ring	N	N	N
	Single row, no flanges on inner ring	NU	NU	NU
	Single row, 1 flange inner	NJ	NJ	NJ
	Single row, 1 flange outer	NF	NF	–
	Single row, 1 flange inner, with retaining ring	NUP	NUP	NUP
	Single row, 1 flange inner w/stabalizing ring	NH	NH	NH
	Double row, flanges outer/flanges inner	HJ	HJ	HJ
		NNU/NN	NNU/NN	NNU/NN
P/N	Light	2XX	2XX	2XX
	Medium	3XX	3XX	3XX
	Heavy	4XX	4XX	4XX
	Extra Light	10XX	10XX	10XX
	Light, Wide	22XX	22XX	22XX
	Medium, Wide	23XX	23XX	23XX
Suffix	Ployamide cage	T	P	TVP2
	Composite high temp (200°C) cage	T7	–	–
	Machined brass cage	M	M	M,M1
	Pressed steel cage	W,WS	J	JP1
	High capacity design	E	EC	E
	Full complement (no cage)	V	V	V
	Tight clearance	C2	C2	C2
	Normal clearance	BLANK	BLANK	BLANK
	Loose clearance	C3	C3	C3
	Extra loose clearance	C4	C4	C4

Glossary – Spherical Roller Bearings

• Spherical Roller Bearings – Are double row self-aligning bearings capable of carrying heavy radial loads combined with moderate thrust loads in either direction. They are extremely resistant to shock loads and their self-aligning feature allows full capacity loading despite shaft deflection.
• Continuous Caster Rollers – These are 2-split bearing units of a highly reliable design and feature a long service life. Cylindrical roller bearings with self-aligning rings having a proper alignment function.
• Spherical Roller Bearings TL Series – Excellent performance with high temperture equipment. High strength to prevent inner ring fractures.
• Shaker Screen Bearings – Are designed for vibrating applications such as screens, feeders and compactors. These are self-aligning spherical roller bearings designed to accommodate the high loads, static and dynamic misalignment characteristics, and severe environmental conditions inherent in these applications.
• Triple Ring Bearings – Are specially designed for use with controlled crown rolls used extensively in the paper industry. These high load capacity bearings provide “shaft within shaft” operation, while simplifying the surrounding structure and installation.

Interchange – Spherical Roller Bearings

	Description	NSK	SKF	Torr/FAF	FAG
P/N	Very Light	239xx	239xx	239xx	239xx
	Light	230xx	230xx	230xx	230xx
	Light, Wide	240xx	240xx	240xx	240xx
	Medium	231xx	231xx	231xx	231xx
	Medium, Wide	241xx	241xx	241xx	241xx
	Heavy	222xx	222xx	222xx	222xx
	Heavy, Wide	232xx	232xx	232xx	232xx
	Extra Heavy	213xx	213xx	213xx	213xx
	Extra Heavy, Wide	223xx	223xx	223xx	223xx
Suffix	Bronze case, one piece, guide ring	CAM,AM	CA,CACM	YM	M
	Bronze cage, two piece, guide flange	M	MC	BR	MB
	Steel cage, two piece, guide ring	C,CD	CJ,CC	CJ, VJ	BLANK
	Polyamide cage, two piece	H	–	VCF	TVPB
	Tapered bore 1:12	K	K	K	K
	Tapered bore 1:30	K30	K30	K	K30
	Carburized steel, complete bearing	g	ECD	W40	W209
	Carburized steel, inner ring only	g3	ECB	W401	W209B
	Lube groove & holes outer ring	E4	W33	W33	S
	Lube groove & holes outer ring, holes inner ring	E7	W513	W33W94	Sheading0AB
	Holes only outer ring	E3	W20	W20	SY
	Holes only inner ring	E5	W26	W94	heading0AB
	No relube features	BLANK	BLANK	BLANK	–
	Plugs provided for outer ring holes	E42	W77	W84	heading0
	Combination W33, W4, W31	E4P53	W507	W33W4W31	–
	Combination W33, W31	E4U22	W506	W33W31	–
	Combination W33, W26, W31	E7U22	W509	W33W94W31	Sheading0A
	Outer ring w/extra close running accuracy	P52	C04	C04	T52BN
	Inner ring w/extra close running accuracy	P53	C02	C02	T52BE
	Inner & outer ring w/extra close running accuracy	P55	C08	C08	T52BW
	Special inspection measures	U22	W31	W31	–
	Inner ring & outer ring heat stabilized to 200°C	S11	S1	–	–
	Tight clearance	C2	C2	C2	C2
	Normal clearance	BLANK	BLANK	BLANK	BLANK
	Loose clearance	C3	C3	C3	C3
	Extra loose clearance	C4	C4	C4	C4

Glossary – Tapered Roller Bearings

• Four Row Tapered Roller Bearings Are very popular for use on roll necks. Most of these bearings are composed of two double cones (four Inner ring raceways), a cone spacer, two single cups (one at each end), one double cup (the center two raceways in the outer rings), and two cup spacers. They are very effective at operating under heavy radial and axial loads at low to moderate speeds. NSK four row tapered bearings are standardly supplied with carburized rings and rollers and are compatible with industry standards. “Sealed-Clean” bearings are four row tapers with seals for the harshest of operating environments. NSK’s patented design provides the optimum sealing efficiency with only a slight loss of capacity.
• Two Row Tapered Roller Bearings Are very common as the back-up thrust bearing in a rolling mill or as the roll neck in lighter duty rolling mills. Two row tapers are designed in a variety of styles for different applications. Converging bearings (TDI, TDIE, TDIS) consist of one double cone and two single cups possibly with a cup spacer. Diverging bearings (TDO, TDOD, TDOC) consist of two single cones, a cone spacer, and one double cup.

Interchange – Inch Tapered Roller Bearings

	Description	NSK	SKF	Timken	FAG
Prefix	Extra heavy	EH	EH	EH	KEH
	Heavier than heavy	HH	HH	HH	KHH
	Heavy	H	H	H	KH
	Heavy medium	HM	HM	HM	KHM
	Medium	M	M	M	KM
	Light medium	LM	LM	LM	KLM
	Light	L	L	L	KL
	Lighter than light	LL	LL	LL	KLL
	Extra light	EL	EL	EL	KEL
Cup Angle	0° to 23°59’59.99	1xxxx	1xxxx	1xxxx	1xxxx
	24° to 25°29’59.99	2xxxx	2xxxx	2xxxx	2xxxx
	25°30′ to 26°59’59.99	3xxxx	3xxxx	3xxxx	3xxxx
	27° to 28°29’59.99	4xxxx	4xxxx	4xxxx	4xxxx
	28°30′ to 30°29’59.99	5xxxx	5xxxx	5xxxx	5xxxx
	30°30′ to 32°29’59.99	6xxxx	6xxxx	6xxxx	6xxxx
	32°30′ to 35°59’59.99	7xxxx	7xxxx	7xxxx	7xxxx
	36° to 44°59’59.99	8xxxx	8xxxx	8xxxx	8xxxx
	45° up, but not thrust only conforms to AFBMA standard case carburized cup & cone	9xxxx	9xxxx	9xxxx	9xxxx
		R
		G

Interchange – Metric Tapered Roller Bearings

	Description	NSK	SKF	Timken	FAG
P/N	High capacity design	HR	–	–	–
	Light	HR302xx	302xx	302xx	302xx
	Medium	HR303xx	303xx	303xx	303xx
	Medium, steep angle	HR303xxD	313xx	313xx	313xx
	Extra light, wide	HR329xx	329xx	329xx	329xx
	very light, wide	HR320xx	320xx	320xx	320xx
	Light, wide	HR322xx	322xx	322xx	322xx
	Medium, wide	HR323xx	323xx	323xx	323xx
	Very light, extra wide	HR330xx	330xx	330xx	330xx
	Light, extra wide	HR331xx	331xx	331xx	331xx
	Medium, extra wide	HR332xx	332xx	332xx	332xx
Suffix	Medium contact angle	C	B	B	B
	Steep contact angle	D	–	–	–
	Modified internal design	X	X	X	X
	Conforms to ISO 355	J	–	–	A