ADVANCED BEARING

SOLUTIONS FOR THE WIND

INDUSTRY
Wind turbines generate electricity under adverse
and constantly changing conditions, both on and
offshore. Efficient power generation from wind
turbines demands high performance from every
component – particularly the bearings used in the
turbine drivetrain and gearbox.

NSK rolling bearings for these applications perform

with robust resistance to seizure, wear, flaking and
unique challenges such as white etching cracks
(WEC) to deliver advanced product design solutions
for a reliable and sustainable operating life.

WIND INDUSTRY 3
A GLOBAL PARTNER AND SOLUTIONS PROVIDER

As a leading manufacturer of rolling bearings, linear technology components and steering systems, NSK NSK has a long tradition in patent applications for machine parts. In our worldwide research centers, we
can be found on almost every continent – with production facilities, sales offices and technology centers not only concentrate on the development of new technologies, but also on the continual improvement
– providing our customers with responsive decision-making channels, effective logistics and local service. of quality based on the integrated technology platform of tribology, material technology, numerical
simulation and mechatronics.

TRIBOLOGY:

Improving Performance by Optimizing Friction. Tribology is the study of friction and wear
of contact surfaces in relative motion, such as rotating parts that endure enormous forces
with a thin oil film. Severe operating conditions are optimized through lubrication and surface
Europe treatments developed by NSK, resulting in superior performance for applications requiring low
friction, high-speed rotation, quiet operation or enhanced durability.
Asia
MATERIALS:

CORE TECHNOLOGIES
Oceania Superior Performance for Any Application. Materials research and development affects
nearly every aspect of product performance. Through careful selection of material
The Americas Africa composition, heat treatment and use of alternative materials, NSK enables optimization of
application performance. This may be through improvements in product function, endurance,
and reliability or through improvements in production and process cost efficiency.

NUMERICAL SIMULATION:

Turning Blind Risk Into Trusted Reliability. In the past, accuracy and reliability in product
development were achieved with experience-based design and longer testing periods. NSK’s
simulation technology allows for virtual validation to accelerate design and production.
Extreme conditions or innovative designs that defy previous expectations can also be
THE NSK COMPANY: evaluated and analyzed.

THE AMERICAS EUROPE / AFRICA ASIA / OCEANIA

NSK commenced operations as the first Japanese manufacturer MECHATRONICS:
of rolling bearings in 1916. From the outset, we have been
Technology for a Safe and Comfortable Future. Mechatronics refers to the combination of
continuously expanding and improving not only our product
MANUFACTURING mechanics and control technologies. NSK has cultivated knowledge of mechanics through
9 9 46
portfolio but also our range of services for various industrial SITES
years of product development and production. This knowledge is used in conjunction with
sectors. In this context, we develop technologies in the
motors, sensors and circuits to develop mechatronic systems that add new functions,
fields of rolling bearings, linear systems, components for the
improve reliability and increase performance in various industries while also improving
automotive industry and mechatronic systems. Our research SALES LOCATIONS 21 15 83
convenience and safety in our daily lives.
and production facilities in the Americas, Europe and Asia
are linked together in a global technology network. Here we
concentrate not only on the development of new technologies, TECHNOLOGY
2 3 10
but also on the continuous optimization of quality – at every CENTERS

process stage.

4 WIND INDUSTRY 5
EVERY SOLUTION CALLS FOR THE RIGHT PRODUCTS

Whether for the main drive stage or accessories, our broad range of rolling bearing products deliver
reliable and sustainable operating life for a wide variety of applications.

CYLINDRICAL CYLINDRICAL TAPERED TAPERED ROLLER

MAIN ROTOR SHAFT SPHERICAL DEEP GROOVE
1 ROLLER ROLLER ROLLER BEARINGS - FOUR-POINT
1 ROLLER BALL
BEARINGS - BEARINGS - BEARINGS - DOUBLE ROW / BEARINGS
2 MAIN GEARBOX BEARINGS BEARINGS
SINGLE ROW DOUBLE ROW SINGLE ROW DUPLEX

3 GENERATOR

2 YAW DRIVE
4
3 5 PITCH DRIVE

MAIN ROTOR
SHAFT

MAIN GEARBOX
5

GENERATOR

PITCH / YAW
4 GEARBOX

MAIN ROTOR SHAFT MAIN GEARBOX GENERATOR PITCH AND YAW GEARBOX
The rotor induces high axial and radial loads in the main A variety of gearbox arrangements have been implemented Generators primarily use deep groove ball bearings and Yaw gearboxes turn the nacelle into the wind or away from it.
bearings, which occur both statically and dynamically. Given for wind turbines in recent years. Megawatt-class systems cylindrical roller bearings. Transmission of electrical current Pitch gearboxes are required for rotor blade adjustment. Deep
such loads as these, high bearing stiffness is indispensable. often combine planet gear stage(s) with multiple parallel gear can damage the rolling bearings and shorten their service groove ball bearings, cylindrical roller bearings, spherical roller
Spherical roller bearings used in the 3 point drivetrains, or stages. Deep groove ball bearings, spherical roller bearings, life. In order to avoid this damage, the use of insulated rolling bearings and tapered roller bearings are typically installed in
cylindrical and tapered roller bearings used in the modular cylindrical roller bearings, tapered roller bearings and bearings should be considered. NSK offers coated rolling these gearboxes.
drivetrain, are particularly well-suited for this application. four-point contact ball bearings are used, depending on the bearings where an insulating coating has been applied to the
location of the bearing. outer rings.

6 WIND INDUSTRY 7
MAIN SHAFT BEARINGS

3-POINT SUSPENSION SPHERICAL ROLLER BEARING

CA DESIGN
One of the most common wind turbine
architectures is the 3-point suspension. In this
configuration, a single main spherical roller CA series spherical roller bearings with heavy duty machined
bearing is used to support the main shaft and brass cage have extremely high load capacity and superior
wind loading. The other end of the main shaft is durability. With optimized internal geometry, they are
rigidly mounted to the input shaft of the gearbox especially suitable for applications with heavy loads, shock
and relies on the gearbox’s flexible trunion conditions and misalignment, delivering high performance in
system to share the loading through the gearbox’s large rotor shaft arrangements even at low speeds. Available
input shaft bearings. All of the wind loading with Super-TF long-life steel.
generated by the rotor, as well as its torque,
must be safely transmitted through the gearbox
structure and mounting system to the wind
turbine’s frame.

Bearing Selection: Spherical Roller Bearing, TAPERED ROLLER BEARINGS

CA Design DOUBLE ROW

NSK double-row tapered roller bearings are designed with

a single inner ring, 2 roller/cage sets and 2 outer rings with
spacer. Optimized large-size rollers guided by high strength,
wear resistant cages deliver high capacity for combined
MODULAR DRIVETRAIN
heavy radial loads and axial loads in both directions. In
The modular drivetrain architecture is a typical inch and metric dimensions with normal contact angle (KH
configuration consisting of two main bearings that design) or with steep angle races (KDH design) for increased
support a separate main shaft. This main shaft is axial load capacity. Available with Super-TF long-life steel.
also rigidly connected to the gearbox input shaft.
The bearings supporting the main shaft isolate the
wind loading from the gearbox and its bearings.
Only deflections and tolerances may cause
additional reaction loads in the gearbox bearings. CYLINDRICAL ROLLER BEARINGS
Often the reaction loads at the bearings cannot SINGLE ROW
easily be calculated in this statically indeterminate
drivetrain configuration. Optimized size and profile of rollers guided by high precision
machined cages deliver higher load ratings and smooth
Bearing Selection: Tapered Roller Bearing, rotation in main shaft applications, even at very low speeds.
Single Row or With heavy duty precision machined brass cage or pin-type
Double Row KDH or KH Design cages. Available with Super-TF long-life steel.

Cylindrical Roller Bearing

Single Row NU, NJ or NF Design

8 WIND INDUSTRY 9
MAIN GEARBOX BEARINGS

CYLINDRICAL ROLLER BEARINGS, FULL

5 COMPLEMENT
3
Cage-less full complement cylindrical roller bearings have
2 the maximum possible number of rollers and can sustain
1 much heavier loads than cylindrical roller bearings of the
same
size with cages. In single row NCF and double row NNCF
series. Available with Super-TF long-life steel and black
oxide coating.

Bearing Location: Planetary Carrier

Planetary Gear

CYLINDRICAL ROLLER BEARINGS, SINGLE ROW

Featuring NSKHPS high performance standard for increased

load capacity and speed ratings, NSK single row cylindrical
6
roller bearings deliver high strength and radial rigidity for
high loads and speeds. Optimized internal geometry
promotes lower running temperature and quiet operation.
4
Available with AWS-TF long-life steel specialized to prevent
white etching cracks. Also available with Super-TF long-life
steel and black oxide coating.
1 LOW SPEED SHAFT

2 PLANETARY GEAR Bearing Location: High-Speed Intermediate Shaft

High-Speed Shaft
3 PLANETARY CARRIER

HIGH-SPEED
4 INTERMEDIATE SHAFT

HIGH-SPEED SHAFT
NSKHPS CYLINDRICAL ROLLER BEARINGS, EM CAGE
5
CONDUIT TUBE › Bearing life increased as much as 2x compared to conventional designs
6
› As much as 23% higher basic load rating
› High strength and maximum rigidity for high loads and high speeds PERMISSIBLE MISALIGNMENT
Cr LIFE
› Higher permissible misalignment
22XXE, 23XXE 2XXE, 3XXE

Through close collaboration with our wind industry partners,

NSK has gained tremendous insight into the complex Conventional 1 1 2’ 4’

conditions that impact wind turbine operation – none more

profoundly than within the gearbox. Our advanced product
development takes into consideration the continuous variation NSKHPS 1.23 2 4’ 4’
Fr Misalignment Fr Misalignment
and fluctuation of factors such as lubrication, loads, stresses,
CONVENTIONAL NSKHPS
vibrations and temperatures to deliver reliable and cost-
effective operating life.

10 WIND INDUSTRY 11
 FOUR-POINT CONTACT BALL BEARINGS TAPERED ROLLER BEARINGS, DUPLEX

Four-point ball bearings are designed with a 35° contact Duplex tapered roller bearing arrangements feature two
angle and an inner ring that is split radially into two pieces. single row bearings and an outer ring spacer, as equivalent
Cage is machined brass. Their design allows one bearing to
singles or as a major/minor set. They can accommodate
sustain significant axial loads in either direction with high
capacity. They are capable of accommodating pure axial heavy radial loads and axial loads in both directions.
loads or combined loads where the axial load is higher. Available with Super-TF long-life steel or AWS-TF long-life
Available with Super-TF long-life steel and black oxide steel specialized to prevent white structure flaking. Also
coating. available with black oxide coating.

Bearing Location: High-Speed Intermediate Shaft Bearing Location: High-Speed Intermediate Shaft
High-Speed Shaft High-Speed Shaft
Low-Speed Intermediate Shaft

DEEP GROOVE BALL BEARINGS TAPERED ROLLER BEARINGS, SINGLE ROW

NSK Deep Groove Ball Bearings are designed to deliver Single row tapered roller bearings have high radial and axial
unsurpassed performance for a wide variety of applications. rigidity, and are capable of taking high radial loads and
Precision high-grade balls and super-finished raceways moment loads as well as axial loads in one direction. NSK
provide smooth and quiet operation. For low to medium offers a range of large size, dimensionally specialized single
radial loads and smaller axial loads in both directions. row tapered roller bearings for main gearbox applications in
Advanced lubricant technology and sealing designs ensure both metric and inch configurations. Available with Super-TF
optimum performance and reliability. Available in NSKHPS long-life steel and black oxide coating.
series with pressed steel cage or machined brass cage.
Bearing Location: Planetary Carrier
Bearing Location: Conduit Tube

TAPERED ROLLER BEARINGS, DOUBLE ROW

BLACK OXIDE COATING FALEX TEST
(BOC)
Double row tapered roller bearings feature two roller/cage
14
Black oxide coating is an Speed = 191 rpm
sets and two outer rings with spacer on a single inner ring.
Load = 50 kgf/min
12
effective surface treatment to Lubrication = ISO VG320
They can accommodate heavy radial loads and axial loads
500ml
counteract bearing damage 10
in both directions. Available in normal contact angle (KH
TORQUE (N*m)

due to slippage that occurs 8

design) or with steep angle races (KDH design) for increased
typically during start-up. It can 6
axial load capacity. Available with Super-TF long-life steel
be used in all main gearbox
bearing locations for optimum
4
and black oxide coating.
2
protection and performance.
Bearing Location: Low-Speed Intermediate Shaft
200 400 600 800 1000 1200 1400
TIME (sec)

NO BLACK OXIDE COATING BLACK OXIDE COATING

12 WIND INDUSTRY 13
GENERATOR BEARINGS ADVANCED SOLUTIONS – NSK TOUGH STEEL

CERAMIC COATED INSULATING BEARINGS The valuation of a wind turbine includes one major maintenance cycle during its 20-year life
expectancy. As such, the need for improved durability in bearing performance is a critical
NSK ceramic coated bearings provide superior insulation
consideration to achieve the greatest reliability and total cost performance – even in uniquely
properties to prevent electrical erosion or arcing in bearings
used in turbine generators. An optimized alumina-based demanding operating conditions. In response, NSK has applied our Tough Steel technology to
ceramic material combined with a blend of additives is used develop bearing solutions that set a new standard for long service life.
to coat the outer ring, offering a high resistance to the flow
of electrical current. The coating is tough and durable when
impacted on its corner surfaces, and possesses excellent heat
dissipation properties. Boundary dimensions are identical to
a standard bearing, enabling easy replacement without need
for modifications.

Bearing Location: Generator

SPECIFICATION NSK CERAMIC INSULATION HD2

Application Generator

Insulating material AI203

Insulation resistance (1000VDC) Over 100MΩ

Breakdown voltage Over 4kV

Boundary dimension ISO standard

NSK’s Super-TF (STF) series bearings are designed

to deliver outstanding durability in operating
environments subject to contamination. Utilizing
advanced material engineering and heat treatment
technology, they perform with superior resistance
to wear and seizure under contaminated lubrication
conditions. For the specific challenge of hydrogen
induced embrittlement impacting bearings used in
turbine gearboxes, NSK has introduced our AWS-TF
technology to attack premature bearing failure at
the core of its generation: the metallurgy.

Outstanding toughness, performance, and total

cost-savings: NSK technology sets a new standard
for long service life.

14 WIND INDUSTRY 15
SUPER TF AND AWS-TF BEARINGS

In its quest for longer bearing service life, NSK has spent many years analyzing the mechanisms of AWS-TF AND WHITE STRUCTURE FLAKING
fatigue in bearings and researching and developing materials, heat treatment processes and operating
Hydrogen embrittlement is a prevailing bearing failure
conditions. The range of approaches to achieving longer service life taken by our research team are 1.0
mode found in wind turbine applications. It is a process by
shown in Fig. 1. The technology incorporated in our AWS-TF and Super-TF Bearings is designed to 0.8 which hydrogen penetrates into the bearing steel, causing
maximize service life under conditions where bearings are subject to hydrogen induced embrittlement it to weaken. Hydrogen itself is generated by typical
0.6
tribomechanical and tribochemical events occurring to the
and contamination induced surface-originating flaking.

R/C VALUE
0.4
bearing lubricant during operation of the wind turbine. White
structure forms below the surface of the bearing, and this
0.2 change to the microstructure results in the formation of
SUPER-TF AND SURFACE-ORIGINATING FLAKING cracks that will extend to the surface of the bearing under
0
GOAL : LONGER SERVICE LIFE 0 10 20 30 40 50 60 stress concentration during operation. Cracks propagate
Bearings can be required to operate under conditions RETAINED AUSTENITE LEVEL % under the load of each passing roller, leading to flaking and
PROBLEM
CLEAN ENVIRONMENTS CONTAMINATED ENVIRONMENTS where lubrication is easily contaminated. Metal particles ultimately bearing failure.
FIG. 2 RELATIONSHIP OF R/C VALUE TO RETAINED AUSTENITE LEVEL
SUBSURFACE- SURFACE-ORIGINATING WHITE STRUCTURE or casting sand in the lubricant create dents in the rolling
ORIGINATING FLAKING FLAKING FLAKING / CRACKING
contact surfaces, and stress concentrated around these With our AWS-TF bearings, NSK has countered white structure
dents eventually leads to cracking and to surface-originating flaking by applying the technology of Tough Steel long-life
400
flaking. The ability to reduce the concentration of stress materials. White structure flaking tends to be generated
MATERIAL MATERIAL MATERIAL SUPER-TF BEARING
around the shoulders of surface dents is directly related to 300
when hydrogen becomes concentrated at stress points.
REDUCTION OF OPTIMIZED INCREASED
achieving longer service life from the bearing. NSK optimizes additional chromium content in our bearing

NUMBER
NON-METALLIC COMPOSITION CHROMIUM
INCLUSIONS
200 steel composition to significantly decrease the diffusion
APPROACHES HEAT TREATMENT
NSK research and development of material properties rate of hydrogen and delay microstructural change,
100
TOUGHNESS
has revealed that a high level of retained austenite is thereby increasing resistance to white structure flaking.
CARBURIZATION
an extremely effective means of maximizing the r/c 0
In rolling fatigue life tests conducted in hydrogen charged
CONTROL OF
HIGH PURITY
RETAINED AUSTENITE value around surface dents in the bearing material (see CARBIDE SIZE (MM) 0.2 0.4 0.6 0.8 1.0 1.2
environments, increasing chromium content proves to ensure
Fig. 2) - the greater the r/c value, the smaller the stress longer life performance.
concentration. TF technology in general is a unique heat FIG. 3 AVERAGE DIAMETER OF CARBIDE AND CARBONITRIDE
CONTAMINATION PARTICLES IN A SUPER-TF BEARING
RESISTANT BEARINGS treatment process developed by NSK to optimize the level of
retained austenite in bearing materials.
400
Z STEEL
However, austenite itself has a soft microstructure, reducing ORDINARY CARBURIZED
300 STEEL
MASS-PRODUCED
STEEL
the hardness of the bearing material. To meet the needs for
CARBONITRIDING

NUMBER
greater hardness with a higher level of retained austenite,
200
SUPER-TF BEARINGS AWS-TF BEARINGS
NSK adopts a technique to promote the uniform distribution
PRODUCTS &
SOLUTIONS and reduce the diameter of carbide and carbonitride 100

particles in the bearing material. Super-TF bearing steel

contains appropriate amounts of chrome and molybdenum 0
FIG. 1 APPROACHES TO ACHIEVING LONGER SERVICE LIFE FROM BEARINGS
to optimize the formation of carbides. CARBIDE SIZE (MM) 0.2 0.4 0.6 0.8 1.0 1.2

FIG. 4 AVERAGE DIAMETER OF CARBIDE PARTICLES IN AN

Figures 3 and 4 illustrate that Super-TF Bearings have a ORDINARY CARBURIZED STEEL BEARING

greater amount of fine-size carbide and carbonitride particles

than ordinary carburized bearings, giving them a greater
degree of hardness and higher retained austenite for a long
service life.

16 WIND INDUSTRY 17
BEARING FAILURE MODES

SURFACE-ORIGINATING FLAKING COMPARISON OF SERVICE LIFE WHITE ETCHING CRACKS / FLAKING COMPARISON OF SERVICE LIFE

Location: THRUST Location: AWS-TF 6206 SPECIAL

7 TYPE TEST 7 LUBRICANTS TEST
Gearbox - All Bearing Positions (Contaminating foreign Gearbox - HSIMS, HSS P/C = 0.46
matter in lubricating oil)
Main Shaft 6 Pmax = 4.8 GPa 6
N = 3000 min-1
Oil bath lubrication
Super-TF N = 1000 min-1 Solution:
Solution: 5 Oil bath Anti-White Structure TF (AWS-TF) 5
lubrication

SERVICE LIFE RATIO

SERVICE LIFE RATIO
Super-TF (STF) Long-life Steel Long-life Steel Super-TF
4 4
AWS-TF
3 3
Carburized Carburized
2 2

1 2 3 1
SUJ2
1 2 1
SUJ2

debris H H H H
H H

0 0
dent cracking flaking hydrogen white
permeation and diffusion structure change

STF delivers 5 times the life of AWS-TF delivers 7 times the life of
Foreign debris Stress concentration Cracks propagate Hydrogen permeates White structure forms
contamination leads around debris dents under the load of each standard steel (SUJ2), while the bearing steel, below the surface of standard steel (SUJ2), while STF
to the formation of develop into cracks passing roller and AWS-TF delivers 3 times causing it to weaken the bearing delivers 4 times
dents develop into flaking
Crack formation begins along
the boundary of white structure
3 4 Cracks propagate under
the load of each passing roller
during repetitive stressing and develop into flaking

cracking flaking

SKIDDING ELECTRICAL EROSION ADHESIVE WEAR

Location: Location: Location:

Gearbox - LSS, HSIMS, HSS Generator - rotor bearing Main Shaft - 3 point suspension
Planetary Carrier, Planet Gear
Solution: Solution:
Black oxide coating Ceramic coating Solution:
Super-TF (STF) Long-life Steel
Black oxide coating

18 WIND INDUSTRY 19
EXAMPLES: BEARING NOMENCLATURE

SPHERICAL ROLLER BEARING - 3 PT SUSPENSION CYLINDRICAL ROLLER BEARING, SINGLE ROW – HSIMS, HSS

STF 240 /600 CA g5 M E4 C3 U303 NU 23 26 E /S/ M C3 & U303

STF Super-TF long-life steel

240 spherical roller bearing, width series 4, diameter series 0 NU single row cylindrical roller bearing - 2 outer ring ribs,

/600 bore diameter equals 600 mm no inner ring ribs

CA high capacity internal design 23 dimension series (width series 2, diameter series 3)

g5 case hardened inner and outer rings (multiple options available) 26 bore diameter equals 130 mm (reference number x 5)

M machined brass cage E high capacity internal design

E4 lubrication groove and holes in outer ring /S/ black oxide coating

C3 greater than normal radial internal clearance M machined brass cage

U303 special process control for wind turbine bearings C3 greater than normal radial internal clearance

& NSKHPS symbol - High Performance Standard

CYLINDRICAL ROLLER BEARING - MODULAR DRIVETRAIN TAPERED ROLLER BEARING, DOUBLE ROW - LSIMS U303 special process control for wind turbine bearings

STF NJ 28 /710 g5 M CCG338 U303 431 KH 57 55 SA +K CA640 U303 TAPERED ROLLER BEARING, SINGLE ROW - CARRIER SUPPORT
STF Super-TF long-life steel
431 bore diameter equals 431 - 431.999 mm R 431Z -3 /S/ E U303
NJ single row cylindrical roller bearing - 2 outer ring ribs,
KH double row tapered roller bearing
one inner ring rib R single row tapered roller bearing, special dimensions
57 outer diameter equals 570 - 579.999 mm
28 dimension series (width series 2, diameter series 8) 431Z bore diameter equals 431 - 431.999 mm
55 tolerance for inch bearing
/710 bore diameter equals 710 mm -3 serial number
SA special tolerance
g5 case hardened inner and outer rings (multiple options available) /S/ black oxide coating
+K outer ring spacer
M machined brass cage E notch in the outer ring
CA640 special axial clearance
CCG338 special radial internal clearance U303 special process control for wind turbine bearings
U303 special process control for wind turbine bearings
U303 special process control for wind turbine bearings

TAPERED ROLLER BEARING, DOUBLE ROW -

MODULAR DRIVETRAIN TAPERED ROLLER BEARING, DUPLEX - HSIMS, HSS, LSIMS

HR 303 26 J AWS g5 / HR 313 26 J AWS g5 DF +KR U303

STF 460 KDH 65 01 g5 SA +K CA450 U303
HR high capacity
STF Super-TF long-life steel AWS long-life steel, specialized to prevent white structure flaking
303 303: medium width series 0. diameter series 3
460 bore diameter equals 460 - 460.999 mm g5 case hardened inner and outer rings (multiple options available)
313 313: steep angle width series 1. diameter series 3
KDH double row tapered roller bearing, steep angle race DF bearing arrangement is face to face
26 bore diameter equals 130 mm (reference number x 5)
65 outer diameter equals 650 – 659.999 mm +KR outer ring spacer
J ISO conformance
01 tolerance for metric bearing U303 special process control for wind turbine bearings
g5 case hardened inner and outer rings (multiple options available)

SA special tolerance

+K outer ring spacer

CA450 special axial clearance

U303 special process control for wind turbine bearings

20 WIND INDUSTRY 21
CYLINDRICAL ROLLER BEARING, FULL COMPLEMENT –
PLANETARY CARRIER AND GEAR

NNCF 50 44 /S/ V C3 DR U303

NNCF full complement cylindrical roller bearing, double row

50 dimension series (width series 5, diameter series 0)

44 bore diameter equals 220 mm (reference number x 5)

/S/ black oxide coating

V no cage

C3 greater than normal radial internal clearance

DR controlled size variation arrangement

U303 special process control for wind turbine bearings

FOUR POINT CONTACT BALL BEARING – HSIMS, HSS DEEP GROOVE BALL BEARING, CERAMIC COATED - GENERATOR

QJ 3 28 M E C3 U303 63 30 HD2 MR C3 X26 U303

QJ four point contact ball bearing 63 deep groove ball bearing, diameter series 3

3 dimension series 3 30 bore diameter equals 150 mm (reference number x 5)

28 bore diameter equals 140 mm (reference number x 5) HD2 ceramic insulated coating on outer ring

M machined brass cage MR ball guided machined brass cage

E notch in the outer ring C3 greater than normal radial internal clearance

C3 greater than normal radial internal clearance X26 dimensional stabilizing treatment

U303 special process control for wind turbine bearings U303 special process control for wind turbine bearings

DEEP GROOVE BALL BEARING - CONDUIT TUBE

60 26 DDU C3 & AS2S

60 single row deep groove ball bearing, dimension series 0

26 bore diameter equals 130 mm (reference number x 5)

DDU contact seal (non-contact seal and shielded closures available)

C3 greater than normal radial internal clearance

& NSKHPS symbol - High Performance Standard

AS2S grease type and fill

22
CAT. No.E1285 2018 A-2 Printed in Japan©NSK Ltd. First edition published in FEB. 2018