Bearings Catalog (Deep)

Comprehensive catalogue of bearings: rolling-element families, plain/bushing bearings, fluid-film hydrodynamic, magnetic, foil, linear motion. Every series, vendor, part number, tolerance class, cage material, lubrication, and life-calculation formula encountered in industrial practice. SI units primary; imperial cross-referenced where standard.

1. Rolling-Element Bearings — Overview

Rolling-element bearings substitute rolling friction (μ ≈ 0.001–0.005) for sliding friction. Standard architecture: inner ring + outer ring + rolling elements (balls or rollers) + cage (retainer). Life is governed by sub-surface rolling-contact fatigue, modelled by Lundberg-Palmgren (1947) and refined by Ioannides-Harris (1985) and ISO 281:2007.

Basic life equation: L10 = (C / P)^p × 10^6 revolutions, where

L10 = fatigue life reached/exceeded by 90% of bearings
C = basic dynamic load rating (N), tabulated per bearing
P = equivalent dynamic load (N)
p = 3 for ball bearings, 10/3 for roller bearings

Hours form: L10h = (10^6 / 60n) × (C / P)^p, with n in rev/min.

Modified life (ISO 281): L_nm = a1 × a_ISO × L10

a1 = reliability factor (0.21 for 99%, 0.44 for 97%, 0.62 for 95%, 0.81 for 92%, 1.00 for 90%)
a_ISO = combined material/lubrication/contamination factor from chart (function of η_c × P_u / P and κ = ν/ν1)
P_u = fatigue load limit (typically C0/22 for through-hardened steel)
κ = viscosity ratio = ν (operating) / ν1 (required reference)

Static rating C0: maximum load producing permanent indentation < 0.0001 × ball diameter (Brinell limit). ISO 76 governs.

2. Deep-Groove Ball Bearings (DGBB)

Single-row, radial-load primary, modest axial. Workhorse of light/medium industry.

Series (ISO 15):

60xx — extra-light (e.g., 6000 d=10 D=26 B=8 mm; 6004 d=20 D=42 B=12; 6008 d=40 D=68 B=15)
62xx — light (6200 d=10 D=30 B=9; 6204 d=20 D=47 B=14; 6208 d=40 D=80 B=18; 6216 d=80 D=140 B=26)
63xx — medium (6300 d=10 D=35 B=11; 6304 d=20 D=52 B=15; 6308 d=40 D=90 B=23; 6316 d=80 D=170 B=39)
64xx — heavy (6400 series, less common)
16xxx — thin-section (16004, 16005)
618xx, 619xx, 160xx — very thin

Closure variants (suffix):

ZZ (or 2Z) — metal shields, non-contact, low-friction
2RS (or 2RSR, RSL, LLU) — contact lip seals, grease retention
N, NR — snap-ring groove / snap ring fitted
Open — no shields/seals

Cage materials:

Steel pressed (default; suffix typically omitted or J)
Brass machined (M, MA, MB, MP) — high-temp, high-speed
Polyamide PA66 + 25% glass fibre (TN9, TVH, P) — low friction, ~120 °C max
PEEK (TB) — to 250 °C
Phenolic (T) — historical, high-speed lab spindles

Tolerance / precision (ISO 492 + ABMA Std 20):

ISO P0 / ABEC-1 (Class 1) — general industry; runout ≤ 10 µm typical 6204
P6 / ABEC-3 — improved
P5 / ABEC-5 — precision (machine tool grade entry)
P4 / ABEC-7 — high precision (spindles, instruments)
P2 / ABEC-9 — ultra precision (jet engine accessories, dental drills)

Radial internal clearance (ISO 5753):

C2 — tighter than CN
CN (or C0) — normal (default)
C3 — looser (interference fits, hot service)
C4 — even looser (high temp, high interference)
C5 — extra loose

Major OEMs (DGBB):

SKF Sweden — Explorer line E2 (low-energy, +30% L10), reference part 6205-2RSH; list €8–€18 per piece distributor 2025
Schaeffler FAG Germany — Generation C (e.g., 6205-2Z-C3)
NSK Japan — Z9, MOLDED-OIL (sealed pre-lubricated polyolefin)
NTN Japan — ULTAGE series
JTEKT Koyo Japan — EM cage variants
Timken USA — ball bearing branded line since acquisition of MPB and Torrington
NMB Minebea Japan — miniature DGBB (1–10 mm bore; e.g., DDR-104 d=1.5 D=4 B=2)
ZWZ, LYC, HRB — China; ~30–50% lower cost, OEM-grade for industrial
C&U Group China — automotive OEM
Boca Bearings USA — distributor, ABEC-rated specialty
VXB, RBI, NACHI — second-tier

Typical price (6204-2RS): SKF Explorer €4.80 distributor, NSK ¥600, generic Chinese ¥10–20 (~€1.20).

3. Angular Contact Ball Bearings (ACBB)

7000-series. Designed for combined radial + axial loads. Contact angle α determines axial/radial capacity split.

Contact angles (suffix):

B — α = 40° (heavy axial; e.g., 7204B)
AC — α = 25° (intermediate; common spindle)
A — α = 30°
C — α = 15° (light axial, high speed spindle; e.g., 7012C)
E — α = 25° super precision (Schaeffler)

Series:

70xx — extra-light spindle
72xx — light (7200B, 7204AC, 7208C, 7216B)
73xx — medium

Configurations:

Single row (7xxx)
Double row (3xxx; e.g., 3204) — equivalent to 2× angular contact back-to-back
Four-point contact (QJ2xx, QJ3xx) — pure axial in either direction; e.g., QJ208 d=40 D=80
Matched pairs / sets:
- DF (face-to-face, ><) — moderate axial, allows misalignment
- DB (back-to-back, <>) — high tilt stiffness, machine tool spindles
- DT (tandem, >>) — high axial one direction
- DUL / DUM / DUH — universal pairs light/medium/heavy preload

Super-precision spindle:

SKF — 7014 CD/P4ADGA (P4, universal pair, polyamide cage)
NSK Robust series — 7014 CTYNSULP4 (NTN equivalent)
FAG XCB — XCB7014-E-T-P4S-UL
GMN Germany — high-speed grinding spindles, 70k+ rpm
Barden / TimkenMPB — instrument grade

Hybrid spindle bearings (Si3N4 ceramic balls):

NSK Spacea / Robust ceramic — HSP
SKF NitroMax — 7014 CE/HCP4AH
FAG HCB / HCS — HCB7014-C-T-P4S
GMN HCN — high-speed grinding 60–100k rpm
Density Si3N4 = 3.2 g/cm³ vs steel 7.8 (60% less centrifugal load on outer race)
Hardness HV1500 vs HV700 (steel) — longer fatigue life, lower wear
Thermal expansion α = 3.2 × 10⁻⁶ /K vs steel 12 — running clearance more stable
Electrical insulator — important for VFD-driven motor bearings (EV traction)

4. Self-Aligning Ball Bearings

Two rows of balls + spherical outer raceway → tolerates static misalignment up to ±2.5–3°. Lower load capacity than DGBB of same envelope.

Series: 1200 (extra-light), 2200 (light), 2300 (medium)

1206 — d=30 D=62 B=16
2206 — d=30 D=62 B=20 (wider, two rows visible)
2306 — d=30 D=72 B=27

Application: long shafts with deflection, agricultural machinery, conveyors, textiles. Largely displaced in heavy industry by spherical roller (higher capacity) and in compact designs by toroidal CARB.

5. Cylindrical Roller Bearings (CRB)

Rollers instead of balls — line contact gives ~2× the dynamic capacity of equivalent ball bearing.

Variants by flange configuration:

N — flanges on inner ring only (outer ring free; floating bearing position)
NU — flanges on outer ring only (inner free)
NJ — flanges on outer + one inner flange (axial location one direction)
NUP — flanges on outer + one inner + loose collar (axial both directions)
NF — flanges on outer + one inner (similar NJ)
NCF — full-complement cylindrical (no cage; maximum capacity, lower speed)
NN, NNU — double row super-precision spindle (NN3024K + NN3026K machine tool)
RNU — without inner ring (cam follower track roller)

Series: NU2xx, NU3xx, NU4xx, NU10, NU22, NU23, NU30

NU207 — d=35 D=72 B=17, C≈48 kN
NU220 — d=100 D=180 B=34, C≈250 kN
NU2330 — d=150 D=320 B=108, C≈1900 kN
Large mining/marine NU30/30 — bore >300 mm, C > 5000 kN

Cage choices: J pressed steel (default), MA/MP machined brass, TVP2 PA66 reinforced, P PEEK.

Suffix C3: increased clearance for hot interference fits (electric motors).

OEMs: SKF Explorer, NSK HPS, FAG E1, Timken, NTN ULTAGE; Chinese ZWZ/LYC.

6. Needle Roller Bearings (NRB)

Very high ratio L/D ≥ 4 rollers in compact section. Used where radial space is minimum.

Variants:

NA / NK — caged needle bearings with inner ring (NA) or without (NK); e.g., NA4905 d=25 D=42 B=17, NK25/16 d=25 D=33 B=16
HK — drawn-cup needle, open ends (HK1010 d=10 D=14 L=10)
BK — drawn-cup needle, closed end
RNA — without inner ring + machined outer
HF — drawn-cup, one-way (sprag clutch)
KZK / KBK / K — cage + needle assembly only (no rings; shaft + housing form raceway)

Cam followers (stud-type / yoke-type track rollers):

KR, KRV — stud type (M-stud; e.g., KR16 d=6 stud D=16 OD)
NUTR, RSTO — yoke type
McGill CCF/CCFE/CFE — Emerson group, USA reference
Schaeffler INA — KR, KRE, NATR; large catalogue
IKO Japan — high-precision NA/NAS/NAU

Drawn cup load rating (HK1010): C ≈ 6 kN, n_max ≈ 16 k rpm with oil.

7. Tapered Roller Bearings (TRB)

Conical rollers; raceway angles converge to common apex → pure rolling for combined radial + thrust load. Universal in vehicle wheel hubs and industrial gearboxes.

Naming: Timken cone (inner) + cup (outer) part numbers historically; ISO/metric uses 4 digits.

Metric ISO: 30200 series (light), 30300 (medium), 32200, 32300, 33200, 32900, 33000
- 30205 — d=25 D=52 T=16.25; C≈37 kN
- 32308 — d=40 D=90 T=35.25; C≈140 kN
Imperial Timken: LM67048/LM67010 (Ford F-150 inner wheel), HM518445/HM518410, JLM104948/10
Double-row TRB: 352xx (32021×2), 4T-CRI series Timken paired wheel-hub
Hub bearing units (HBU/GEN1/GEN2/GEN3): pre-assembled wheel bearings, ABS-encoder integrated
- SKF VKBA, FAG SP, NSK BAR/HUB, Timken Set bearings

Bearing cup taper angle: 10–30° typical. Steeper = more axial capacity.

OEMs: Timken USA (origin), Koyo (largest TRB producer globally), NSK HRJ series, Schaeffler INA/FAG; Chinese ZWZ + WaFangDian Bearing.

Auto wheel-bearing prices (LM11949/10 trailer): $6-$ 15 distributor; SKF brand $25.

8. Spherical Roller Bearings (SRB)

Two rows of barrel-shaped rollers on spherical outer raceway → self-aligning + high load. Workhorse of heavy industry (conveyors, fans, mills, paper machines, gearboxes, wind turbines).

Series: 222xx, 223xx (light/medium narrow), 232xx, 233xx, 240xx, 241xx (wide), 248xx, 249xx

22216 — d=80 D=140 B=33, C≈360 kN
23130 — d=150 D=250 B=80, C≈1000 kN
240/630 — large mill bearing, bore 630 mm, OD 920 mm

Bore variants:

Cylindrical bore (default; e.g., 22216 E)
Tapered bore (K, K30 — 1:12 or 1:30 taper) — mounted on adapter sleeve (H, HE) or withdrawal sleeve (AH, OH)

Cages: CC (steel pressed window), CA (machined brass), MB (machined brass), VA405 (railway), TVP2 (polyamide).

OEM premium grades:

SKF Explorer — engineered surfaces, optimised geometry, +30% L10 over conventional
Timken Wear Resistant SRB — proprietary heat treatment, +50% in contaminated lubrication
NSK HPS / NSKHPS High Performance Standard — equivalent step up
FAG X-Life — Schaeffler premium tier

Large wind-turbine main shaft:

SKF — 240/630-B-MB main shaft bearing 4 m OD class
Timken — TimkenSteel single billets > 6 m diameter for Vestas V236-15 MW main shaft
Schaeffler — large-bore SRB tapered + cylindrical roller combinations
NSK — main shaft + gearbox planetary

9. Thrust Ball Bearings

Pure axial load, low speed.

Single direction: 51100 series (51104 d=20 D=35 H=10)
Double direction: 52200 series (52204)
Spherical washer base: 51100 + AS aligning washer

10. Thrust Roller Bearings

Cylindrical thrust — 81100 series (81106 d=30 D=47 H=11), 81200, 81300; pure axial heavy load.

Needle thrust — AXK + AS washers (AXK1024 d=10 D=24); shaft pulleys, compact axial location.

Tapered roller thrust — 29200, 29300, 29400 series; very high axial loads in vertical machinery, marine reduction gears, rolling mill thrust blocks.

Spherical roller thrust — 29200/29300/29400 (e.g., 29412 d=60 D=130 H=42); large fan / extruder / propeller thrust; SKF + Timken + NSK reference parts.

11. Specialty Rolling Bearings

Toroidal CARB (SKF proprietary):

CARB C2xxx, C3xxx — self-aligning + axial displacement in floating-position; replacement for cylindrical roller floating bearing where misalignment exists

Thin-section ball / four-point contact:

Kaydon Reali-Slim — KA, KB, KC, KD, KF, KG, KH series; cross-section 5 mm regardless of bore (bore 25 mm–1000+ mm); robotics joints, medical imaging gimbals
INA / Schaeffler — XSU/XSI cross-roller; XSU080188 d=150 D=220 B=25
THK / IKO cross-roller — RB, RU, RA, RE; e.g., RB6013 d=60 D=90 B=13

Slewing rings (turntable bearings) — large diameter (0.3 m – 12 m), with integrated gear teeth:

Rothe Erde (Schaeffler) — leader; wind turbine yaw + pitch bearings
IMO Antriebseinheit + Liebherr + Kaydon + ThyssenKrupp Rotek
Three-row roller, ball, crossed-roller variants
100T excavator turntable: ~ $15 k; o ff s h orecr an e :$ 50k+

Linear-rotary combination bearings:

INA ZARN combined needle + thrust cylindrical
Schaeffler ZARF — for ball-screw fixed ends
IKO + NTN combined

12. Cage Materials in Detail

Material	Suffix examples	Max temp	Notes
Pressed steel	J, M, no suffix	250 °C	Default; low cost
Machined brass CuZn40Pb2	MA, MB, M, M1	250 °C	Heavy / high speed
Polyamide PA66 + 25% GF	TN, TN9, TVH, TVP2, P	120 °C continuous, 160 °C peak	Lightweight, low noise, self-lubricating; degrades in oil ester additives & ammonia
PEEK + 30% CF	TB, FPK	250 °C	Premium high-speed spindle
Phenolic resin	T	100 °C	Legacy; high-speed quiet
Bronze cast	M (some)	250 °C	Marine, corrosion
Silver-plated steel	A, AS	special	Aerospace turbine, sodium-cooled reactor

13. Lubrication

Grease: 80% of bearings; NLGI Grade 2 typical. Base oils 100–460 cSt @ 40 °C. SKF LGEP 2 (EP), LGHP 2 (high-perf high-temp polyurea), Mobilith SHC 220, Shell Gadus S2 V220.

Oil: bath, splash, oil-mist, jet (high-speed spindles up to 1 M DN value), oil-air (precision spindle).

DN value = bore (mm) × rpm. Speed-limit guide:

Standard greased ball: DN < 500k
Premium spindle ball grease: DN < 800k
Oil-air ball: DN ≈ 1.5–2 M
Hybrid ceramic oil-air: DN > 2 M, up to 3 M

Re-lubrication interval (SKF formula):

T_f = K × [(14×10^6 / (n × √d)) − 4 × d] hours
with K = factor (1 horizontal still, 0.5 vertical), n in rpm, d bore in mm

14. Precision Class Cross-Reference

ISO 492 (ball) / 199 (roller)	DIN 620	JIS B 1514	ABMA Std 20 (US)	Notes
P0	P0	Class 0	ABEC-1 / RBEC-1	General
P6	P6	Class 6	ABEC-3 / RBEC-3	Better runout
P5	P5	Class 5	ABEC-5 / RBEC-5	Machine tool entry
P4	P4	Class 4	ABEC-7 / RBEC-7	High precision
P2	P2	Class 2	ABEC-9	Ultra precision
SP / UP / HG (super, ultra, hyper for spindle)	—	—	—	Spindle-specific tighter

ABEC numbers apply to ball; RBEC to roller. ABEC numbers do NOT certify noise/smoothness for skate/cycling marketing claims — runout only.

15. Plain Bearings (Sliding / Bushing)

No rolling elements. Surface couples slide directly. Used where rolling bearings fail: very low speed + high load, very high speed + low load, oscillating motion, dirty environments, dry running.

Bronze bushings:

CDA 932 (SAE 660) — leaded tin bronze, machinable, general-purpose
CDA 863 (manganese bronze) — high strength, heavy industrial
CDA 954 (aluminium bronze) — corrosion resistance, marine
CDA 836 (red brass) — light duty
Vendors: Bunting Bearings USA, Oiles Japan, GGB Bearing Technology

Oilite (porous bronze impregnated with oil):

Patented 1930 (Chrysler/Amplex); 18–25% porosity filled with mineral oil
Self-lubricating up to PV ≈ 50 kPa·m/s
Vendors: Bound Brook Oilite, Bunting Oilite, SKF Pumppac (PEEK alternative)

Polymer / composite plain bearings:

Igus iglide (Germany) — dry-running polymer; >50 grades
- iglide G300 — universal, FDA option, ~200 N/mm² static
- iglide J — low coefficient, low wear soft shafts
- iglide M250 — vibration absorbing
- iglide X — high temp 250 °C continuous, 315 °C peak (PEEK base)
- iglide A180 — FDA / drinking water
- iglide P210 — pressure-resistant, low-friction wet
GGB DU/DP/DX series — PTFE-lined steel-backed (DU sintered bronze + PTFE/lead; DP4 lead-free)
Federal-Mogul / Tenneco AE bearings — automotive engine main + rod bearings, tri-metal Sn-Pb-Cu overlay
Saint-Gobain Norglide — PTFE-bonded steel for low-friction
Kollmorgen / Daido Metal — aerospace bushings

PV limit = pressure × velocity (MPa × m/s); design metric for plain bearings:

Bronze oilite: 0.05–0.2 MPa·m/s
iglide G: 0.5 MPa·m/s
iglide X: 3.5 MPa·m/s
DU bronze/PTFE: 1.8 MPa·m/s
Engine rod bearings (hydrodynamic when running): >35 MPa·m/s

Split bearings (for shafts that can’t be slid through):

Cooper Roller Bearings UK — split spherical roller cartridges
Waukesha / Dodge USA — split pillow blocks
Revolvo / Schaeffler — split design SRBs

Engine bearings (automotive crankshaft main + connecting rod):

Federal-Mogul (now Tenneco DRiV), Daido Metal Japan, Mahle Germany, KS Bearings (Kolbenschmidt), MIBA Austria
Tri-metal: steel back + copper-lead intermediate + tin-lead overlay
Bi-metal aluminium-tin (AlSn20Cu): modern lead-free
Sputtered overlays (AlSn) for highest-load diesel
Polymer overlay (irox) — Federal-Mogul / MAHLE for low friction modern engines

16. Fluid-Film (Hydrodynamic) Bearings

Sliding bearings where load is supported entirely by pressurised lubricant film generated by relative motion of the surfaces. No metal-to-metal contact in steady state.

History:

Reynolds (1886) — Reynolds equation governing pressure in lubricant film
Sommerfeld (1904) — Sommerfeld number S = (μN/P)(R/c)² characterising journal bearing operation
Michell (Australia, 1905) and Kingsbury (USA, 1910) — independently invented tilting-pad thrust bearing; revolutionised heavy machinery

Journal bearings (radial):

Plain cylindrical bore
Pressure-dam, axial-groove, offset-half, lemon (elliptical)
Lobed (2-, 3-, 4-lobe) — increased stability margins
Tilting-pad journal (most stable; multiple pivoted pads)
Vendors: Kingsbury USA, Waukesha Bearings (Dover) USA, Michell Bearings UK (BDC Bearing Development Centre), Pioneer Motor Bearing, Renk Germany

Thrust bearings (axial):

Tapered land (Mitchell-Kingsbury original)
Tilting pad (Kingsbury equalising leveling plates; standard for turbomachinery)
Spring-mat (Waukesha) — pad supported by springs
Vendors: Kingsbury Inc + Waukesha + Michell Bearings + Renk + RotaChok / Voith

Applications: steam turbines (>500 MW units run on tilting-pad thrust + journal sets), gas turbines, large compressors, large electric motors, hydroelectric generators (vertical thrust supporting 1000+ T rotors).

Reynolds equation (1D): ∂/∂x (h³/12μ · ∂p/∂x) = (U/2) ∂h/∂x

Solved analytically (Sommerfeld, half-Sommerfeld, Gümbel boundary conditions) or numerically (finite difference, finite element).

17. Magnetic Bearings

Active Magnetic Bearings (AMB) levitate the rotor using electromagnets controlled by position feedback. Zero contact, zero friction, no lubrication.

Architecture:

8-pole (or 12-pole) stator electromagnets per radial bearing
Position sensors (eddy-current or inductive) ~120° apart
Real-time controller (PID or H∞ robust) closes loop at 5–20 kHz
Touch-down bearings (rolling-element backup) catch rotor on power loss

Vendors:

SKF Magnetic Bearings (S2M, France) — turboexpander, compressor
Synchrony / Waukesha (Dover) — natural gas pipeline compressors
Calnetix Technologies — turboexpander, blower
Mecos (Mecos AG, Switzerland) — sub-systems
Foreva (Foreva, France) — homopolar bearings
Mitsubishi Heavy Industries — proprietary for chillers

Applications:

Natural gas pipeline turbo-compressors (CO2-free hermetic; e.g., MAN/Siemens HOFIM, Dresser-Rand DATUM ICS) — 5–30 MW
Turbomolecular vacuum pumps (semiconductor; Pfeiffer HiPace, Edwards STP)
Centrifugal chillers (Smardt, Turbocor Danfoss Turbocor TT/TG series) — oil-free
Flywheel energy storage (Beacon Power, Amber Kinetics)
Spindles (very high speed grinding, specialty)

Permanent-magnet bias hybrid — combines permanent-magnet bias flux with control electromagnets → lower power. Calnetix, Waukesha, SKF S2M.

Passive magnetic — repulsion only; cannot fully levitate per Earnshaw’s theorem; used as auxiliary stabiliser.

18. Foil Bearings (Air / Gas Bearings)

Compliant foil supports rotor on hydrodynamic air/gas film. Lift-off at modest rpm; pure non-contact at full speed.

Variants:

Bump-foil (Brayton cycle; Capstone microturbines, R&D Dynamics) — corrugated bump foil under smooth top foil
Leaf-foil / overlapping (Mohawk Innovative Technology / Beachley)
Tilting-pad foil

Applications:

Capstone Green Energy C30/C65/C200/C1000 microturbines (oil-free; air bearings throughout)
ABB Turbocharger air bearings for fuel cells
Honeywell turbochargers (research)
Auxiliary power units (APUs) Honeywell AlliedSignal
Cryogenic turboexpanders (R&D Dynamics)

Performance: load 5–50 N/cm²; lift-off speed 5–20k rpm; max DN > 4 × 10⁶.

19. EHL (Elastohydrodynamic Lubrication)

Regime governing rolling-element bearings. Lubricant film is thin (0.1–1 µm) but pressures are 1–4 GPa, causing piezoviscous behaviour and elastic flattening of contact.

Hamrock-Dowson formula (1981) for minimum film thickness in elliptical EHL contact: H_min = 3.63 U^0.68 G^0.49 W^(−0.073) (1 − e^(−0.68k))

dimensionless groups:

U = η₀ u / (E’ R_x) (speed)
G = α E’ (materials, α = pressure-viscosity coefficient)
W = w / (E’ R_x²) (load)
k = ellipticity ratio

Lambda ratio Λ = h_min / σ_composite (composite RMS roughness)

Λ > 3 → full-film EHL (long life)
1 < Λ < 3 → mixed EHL (asperity contact)
Λ < 1 → boundary lubrication (life severely reduced)

20. Linear Motion Bearings

20.1 Recirculating Ball Linear Guides (Profile Rails)

Most-used linear bearing in CNC and automation. Steel rail + ball-recirculating carriage; high stiffness and accuracy in all directions.

THK Japan (origin, Hiroshi Teramachi, 1972):

SHS — heavy load, 4-row, ball-cage (high speed, low noise); SHS15/20/25/30/35/45/55/65
HSR — heavy load, 4-row; legacy
SR — radial load, 2-row
SSR — wide-low type
HCR — curved rail (radius track)
Ball-cage (Caged Ball) — silent, even ball spacing, +30% L10
Tolerance / preload: C, H, P, SP, UP; preload Z0, Z1, Z2

Hiwin Taiwan:

HG — heavy load 4-row (HGH15CA/CC, HGW20CC, HGH25); equivalent to THK SHS
EG — economic 4-row
MGN / MGW — miniature (MGN5/7/9/12/15) bore 5–15 mm
QH — silent

Bosch Rexroth Germany:

eR Runner Block — economic
KWE — heavy precision
SLS / KWE / SNS — modular variants

NSK Japan:

LH, LU, LE — heavy load
LA-LSS — low-noise ball-cage equivalent

INA / Schaeffler:

KUVE, KUSE, KUME — KUVE25-B-EC
KIT — economic
KWE — wide

Other: IKO Nippon Thompson (Japan; LWE/LWES/LWFF/LWLG), Rollon (Italy, mid-tier), PMI Taiwan, ABBA Taiwan, CPC Taiwan, HepcoMotion (UK; combined linear/curved).

Load ratings (HGH25CA): C = 19.3 kN, C0 = 31.5 kN; static moment 360 N·m roll.

20.2 Roller Linear Guides

Roller elements instead of balls → 2× capacity, 3× stiffness, smaller deflection.

Schneeberger Switzerland — MR (Monorail), MR15/25/35/45/55/65; benchmark
THK SRG / SRN roller LM
INA RUE/RUS — heavy-load roller
Hiwin RG — roller equivalent of HG
NSK NH/NS — roller

Used in machine tools (5-axis machining centres, grinders), heavy-load positioners.

20.3 Needle Linear Bushings

INA KN/KH — needle roller flat cage between hardened plates
Misumi LFR — linear flat roller assemblies

20.4 Air Bearings (Linear)

Porous-media or orifice-restricted compressed air; no contact, sub-nanometre repeatability.

Newport Air-Bearing Stages — semiconductor metrology
Aerotech ABL-A / ABL-X series — porous-carbon air bearing linear stage
NSK Precision (USA, ex-RHP Megatorque) — semiconductor lithography
ABTech, Professional Instruments (PI air bearing spindles)
Loadpoint UK — diamond-turning + grinding
IBS Precision Engineering NL — metrology

Load capacity 100 N – 10 kN, stiffness up to 1000 N/µm, straightness < 0.1 µm/m.

20.5 Magnetic Linear / Maglev

Short-stroke voice-coil or linear-motor levitated stages. Specialised lithography (ASML EUV wafer stages — water-cooled iron-core linear motors with mag-lev planar) and high-precision instruments.

20.6 Plain Linear Bushings

Igus DryLin — polymer linear plain bushings (DryLin W rail; DryLin T profile)
Misumi LSP — sintered bronze sliding bushings on round shaft
THK / NB / NTN ball bushings — recirculating ball on round shaft (LM bushings, e.g., LM12UU bore 12 mm); economic

21. Computational Tools

SKF Bearing Select — online catalogue + life calculator
SKF SimPro Quick / SimPro Expert — multi-bearing system simulator
NSK Bearing Doctor — failure diagnosis app
NSK Bearing Genius — sizing app
Schaeffler bearinx — system-level bearing simulation, gearbox/wind shaft
Schaeffler medias — online catalogue
Timken Engineering Manual + Bearing Selector
NTN BNR — online catalogue
ABMA online standards portal
ROMAX nexus rotordynamics + bearing
MASTA SMT — Smart Manufacturing Technologies UK; gearbox + bearing FEA
KISSsoft + KISSsys — Switzerland; gearbox + bearing module
ANSYS rotor dynamics + bearing contact (manual coupling)
COMET / COMBROS (ARMD by RBTS Inc) — fluid-film bearing & rotordynamics
THK / Hiwin / Bosch sizing tools (linear)
IGUS expert dry-tech sizing
DyRoBeS — fluid-film + rotordynamics
ANL (Argonne) BeAMR — research code

22. Condition Monitoring

Vibration-based methods dominate.

Standards: ISO 10816 (general vibration severity), ISO 13373 (condition monitoring vibration), ISO 18436 (training/cert), ISO 15243 (rolling-bearing failure modes).

Bearing fault frequencies:

BPFO = (N_b/2)(1 − d/D cos α) × f_r — outer race
BPFI = (N_b/2)(1 + d/D cos α) × f_r — inner race
BSF = (D/2d)(1 − (d/D cos α)²) × f_r — ball spin
FTF = (1/2)(1 − d/D cos α) × f_r — cage / fundamental train

with N_b balls, d ball dia, D pitch dia, α contact angle, f_r shaft rpm/60.

Bearing damage detection 4-stage (SKF / SPM):

Sub-surface stress, no visible damage; only ultra-high-frequency stress wave detection (acoustic emission, SPM HD, SKF SEE — Spectral Emitted Energy)
Surface micro-spall; detected by enveloped acceleration spectrum (envelope analysis)
Visible spall / cracking; detected by vibration FFT, bearing-defect frequencies
Late stage; broadband random vibration, audible noise, temperature rise → imminent failure

Hardware:

SKF @ptitude Observer + IMx-S online
SKF Microlog Analyzer handheld
SPM Instrument SPM HD spectrum
Brüel & Kjær Vibro
Emerson AMS Asset Monitor + CSI 2140
Hansford Sensors + Wilcoxon — IEPE accelerometer probes
Petasense + Fluke 3563 wireless

23. Failure Modes (ISO 15243)

Fatigue (sub-surface or surface-initiated spalling) — primary intended life-end
Wear (abrasive, adhesive, fretting) — contamination or insufficient lubrication
Corrosion (moisture, friction corrosion / fretting corrosion, fretting brinelling)
False brinelling — stationary vibration creates Hertz-contact wear marks
True brinelling — single overload indentation
Smearing / scuffing — sliding under load (skidding)
Cage damage — overload, vibration, misalignment
Indentation (debris) — contamination causes localised plastic deformation
Electrical erosion — VFD shaft currents cause fluting and craters
- Mitigation: shaft grounding rings (AEGIS SGR by Electro Static Technology), hybrid ceramic bearings, insulated outer ring (INSOCOAT SKF; FAG J20AA Al₂O₃ plasma-sprayed)
Plastic deformation — overload from shock

24. Notable Markets & Trends

Wind turbines:

Main shaft: large SRB or tapered roller; SKF Nautilus, Timken Wear Resistant for offshore
Gearbox: cylindrical, tapered, spherical roller; Schaeffler X-Life with white-etching-crack resistant steel
Yaw + pitch: slewing rings (Rothe Erde, ThyssenKrupp Rotek, IMO)
Generator: ceramic-hybrid (current insulation)
15+ MW offshore (Vestas V236-15, Siemens Gamesa SG 14-222 DD, GE Haliade-X) — bearings up to 6 m

Electric vehicles:

Traction motor bearings — small DGBB; current-erosion risk from high-frequency VFD inverter
Solutions: hybrid ceramic (SKF NitroMax), insulated INSOCOAT, conductive grease, shaft grounding ring
Increased speed (12–20k rpm) vs ICE accessory bearings
E-axle bearings: Schaeffler eRE, NSK EV-Bearing, SKF Energy Efficient series

Semiconductor lithography:

ASML EUV wafer + reticle stages: planar mag-lev linear motors + air bearings; sub-nm positioning
Nikon NSR, Canon FPA — also air-bearing precision stages
Vacuum-compatible bearings (Spacea-NSK MOLDED-OIL, Igus iglide PEEK)

Medical robotics:

Crossed-roller bearings (THK RB, IKO CRBC, INA XSI) for compact high-stiffness joints
da Vinci (Intuitive Surgical) — crossed-roller in EndoWrist and arms
Stryker Mako, Smith+Nephew CORI — robotic surgery arms

Aerospace:

Engine main shaft: hybrid ceramic ball + cylindrical roller (Pratt & Whitney PW1000G, GE9X)
Cage materials: silver-plated steel, AMS 6491 M50 steel races
Vendors: Timken Super Precision (ex-MPB Barden), Schaeffler Aerospace, NSK, SKF Aerospace

25. OEM Summary Table (Global)

OEM	Country	Strengths	Notable lines
SKF	Sweden	All categories; magnetic; condition monitoring	Explorer, Nautilus, S2M magnetic
Schaeffler (FAG + INA)	Germany	Automotive, wind, machine tool, aerospace	X-Life, RotheErde slewing
Timken	USA	Tapered roller (origin), large industrial	Wear Resistant, TimkenSteel
NSK	Japan	Spindle, automotive, EV	HPS, Spacea, Robust
NTN	Japan	Auto + industrial; ULTAGE	ULTAGE, GENMARK
JTEKT Koyo	Japan	TRB volume leader, auto	EXSEV, IL+EM cages
NMB / Minebea	Japan	Miniature DGBB, instrument	Air-bearing, micro
RBC Bearings	USA	Aerospace, defense	Roller, plain spherical
Kaydon	USA (SKF)	Thin-section, slewing	Reali-Slim
THK	Japan	Linear motion leader	SHS, SR, HSR
IKO Nippon Thompson	Japan	Needle, crossed roller, linear	NA series, CRBC
Hiwin	Taiwan	Linear motion, ball screws	HG, MG, RG
LYC	China	Industrial, rail	OEM-grade
ZWZ	China	Heavy industrial	Wind, mill
HRB	China	Auto, industrial	OEM volume
C&U Group	China	Auto OEM	Wheel hubs
WaFangDian Bearing	China	Heavy industrial, TRB	Mining, mill
Boca Bearings	USA	Distribution, specialty	Ceramic, ABEC 5/7
Cooper	UK	Split bearings	Cooper split SRB
Waukesha (Dover)	USA	Fluid-film, AMB	Magnetic, tilting pad
Kingsbury	USA	Tilting-pad thrust	Marine, hydro, turbine
Michell Bearings	UK	Tilting-pad thrust + journal	Marine propulsion
Renk	Germany	Industrial + naval fluid-film	Submarine, ship gearboxes
GGB / Federal-Mogul	USA / France	Plain & engine bearings	DU/DX, tri-metal
Igus	Germany	Polymer plain & linear	iglide, DryLin
Bunting	USA	Bronze bushings, sintered	CDA 932 Oilite
Daido Metal	Japan	Engine bearings, plain	AlSn polymer overlay

Compendium

Explorer

Bearings Catalog (Deep) — Rolling Element, Plain, Fluid-Film, Magnetic, Linear