Products forWind Turbine Generators

CAT. NO. B1002E-4-A

For the Environment …

Main shaft bearings

Wind turbine generators eﬃciently turn one of the elemental

Gearbox bearings

forces of Nature into a stable supply of electric power.
JTEKT has used their 90+ years of friction management
experience to developing world leading bearing,

Generator bearings

sealing and other technologies to the rapidly advancing ﬁeld of
renewable power generation thus enabling Wind Turbines to

Products forperipheral equipment

achieve an operation life of 25 years or more.

12

Main shaft bearingsGearbox bearings

Generator bearings

Products for peripheral equipment

Main shaft bearings of various types and sizes are required to support the diverse wind turbine designs
and the ever increasing size of both onshore and oﬀshore wind turbines.
JTEKT is committed to answering the needs of its customers through high reliability and speedy development.

Gearbox bearings vary greatly in regards to type,load capacity and rotational speed depending on where they are used in the gear train.
JTEKT responds to diversiﬁed customer requests by ensuring optimal designs based on strict calculations.

Electric pitting is a common cause ofbearing failures in wind turbine generators due to stray electrical currents.
Insulated ceramic bearings eliminate electrolytic corrosion (commonly called ﬂuting)and extend bearing life.

Bearings for yaw-drives(Main shaft: An important component that supports the wind load applied by the blades and transfers the rotational torque to the gearbox.)(Gearbox: Mechanism that increases the rotational speed transmitted via the main shaft up to a speed where electric power can be generated.)

Supporting market demands for smaller,
lighter and more reliable bearings,
JTEKT is leveraging new technologies to develop andmass produce industry leading tapered roller bearings.

(Generator: The device that converts rotational energy into electrical energy.)

Rolling elements in insulated ceramic bearings are
made from silicon nitride ceramic (Si3N4)
JTEKT was the ﬁrst company in the world to develop andinstall insulated hybrid ceramic bearings in Wind Turbines.
The use of hybrid ceramic bearings contributes to the reductionof maintenance costs and improves operating eﬃciency.

Responding to market needs,
JTEKT uses special carburized steel and surface treatments help us
to achieve higher reliability under severe lubrication conditions
and high-rotational speed variations.
Ceramic ball・Utilizing advanced roller movement stabilizing technology in ourspherical roller bearings and low-torque design technology of tapered
roller bearings JTEKT has extended the service life of the main shaft
bearing grease by reducing bearing temperature increases.

Characteristic

Tapered roller bearings

Insulated (hybrid) ceramic bearing

Silicon nitride℃800Density

g/cm3

3.2

7.8

Coeﬃcient of linear expansion

1/℃

3.2×10 -6

12.5×10 -6

Vicker's hardness

Hv

1300 to 2000

700 to 800

Young s modulus

GPa310

210

0.29

0.3

Magnetic property
Electrical Conductivity
Material type

FEM analysis model

Main shaft conﬁguration
Bearing with special surface treatment
minimize roller slippage and improves lubricity

At JTEKT s Kokubu Large-Size Bearing Engineering Development Center, we havevalidated our FEM analysis results with full size test equipment. This allows us toconﬁdently optimize the internal and external geometry of the bearings based on
the mathematical analyses of the entire Wind Turbine drivetrain and structure.

Fatigue life more than doubled
Improved life
under misalignment conditions

Optimized crowning

Conductor

Covalent bond

Metallic bond

Main Shaft Oil Seals

・Full rubber material makes installation easy
・MSA-type with dust lip available
for environments with excessive dust

MS-type

MSA-type

All steel bearing
with electric corrosion

Large-Size Bearing Engineering
Development Center

HPI Hydraulic Pumps
HPI hydraulic pumps are highly eﬃcient, lightweight and compact.
They also have a long life and high reliability.

Full rubber seals(MS-type and MSA-type)

Steel rolling element exhibiting
ﬂuting damage:In addition to analytical techniques such as FEM, JTEKT has
developed a bearing analysis system that enables detailed
calculations of bearing life considering rigidity of peripheral
components and lubrication conditions during operation.
With this system, reliable and speedy technical veriﬁcation ispossible, thereby ensuring optimal bearing selection.

* Certiﬁcation acquired November 2015

MagneticInsulator

Compared to bearings with ceramic coated outer rings, hybrid ceramic bearings are notsusceptible to insulation degradation due to handling damage. Additionally, ceramic balls
lower the operating temperature of the bearings; extending both grease and bearing life.

JTEKT s proprietary Shaft System Analysis Program

The high quality of JTEKT bearing materials has been evaluated andconsequently received certiﬁed approval from DNV-GL to increase
our published load ratings by 25%. This allows for more accurate
life predictions and the conﬁdence to use optimally sizes bearings.

Special heat treatment(KE treatment, SH treatment)

・Split MS-type seals also available as replacement

GearboxSpherical roller bearings

Certiﬁed by DNV-GL*

Nonmagnetic

Eliminates electric corrosion and extends grease life

double row tapered roller bearing
with integrated planet gear

Rated capacity improved
1.1 to 1.2 times(R-type design)

180

Comparison of ceramics and bearing steel properties

Main shaft

Technology to improve bearing robustness
Larger rolling element design(bearing steel)Heat resistance

Poisson's ratio
double-row cylindrical roller bearing
for planetary gear

High carbon chromiumJTEKT supplies optimally designed tapered roller bearings andneedle roller bearings that simultaneously provide high reliability
and rigidity needed to withstand extreme wind gusts.

Hydraulic pumpfor pitch brakes
Used for pitch brake hydraulicpower units.
The hydraulic power unit reduces
the rotor speed using a discsimilar to the way disc brakes areused to slow down an automobile.

Hydraulic pumpfor pitch controllers
Steel bearing inner ringwith ﬂuting damage

Shaft deﬂection
Shaft System Analysis
Program model of a wind turbine drivetrain.

Main shaft bearing
rolling element load distribution(rear)

Peak pressure（cc/rev）

（MPa）

0025
0050
0075
0100
0125
0150
0200

0.25
0.5
0.75
11.25
1.5
228.0
28.0
25.0
25.0
20.0
15.0
12.5

ModelCapacity

Peak pressure（cc/rev）

（MPa）

1001

1.02

30.0

1002

2.05

30.0

1003

3.07

30.0

1004

4.09

25.0

1005

5.12

20.0

1006

6.14

15.0

Rolling element load distribution

Machine Tools

Planetary gear bore deformation andload distribution

JTEKT also manufactures high performance Toyoda machining centers
for the production gear boxes and other large wind power components.
Large, Fast and Strong ‒ Top of the class in all three areas
Optimal horizontal machining center for large-size parts machining

Contact stress distribution between roller and raceway

FH1250SXFH1600SW5i

Quick rapid feed rate of 42m/min,fastest in its class

Equipped with TOYOPUC-Touch,a new CNC incorporating smartphone-inspired operability

Large horizontal machining centerMax. workpiece range: Φ 2,400 x 1,800mm
Pallet load capacity: 5,000kg
Pallet size: 1,250 x 1,250mm

3Capacity

Note: The body is made of aluminum alloy.
The photographs are for reference only.

Yaw-driven reduction gear
Main shaft bearing
rolling element load distribution(front)ModelSeries 1

Hydraulic power is used to change
blade pitch angle to insure operation
at the turbine s rated speed.

Generator

A new testing facility has been installed in ourLarge-Size Bearing Engineering Development
Center to evaluate actual wind turbine
drivetrains allowing for higher reliability andshorter customer development periods.

Series 045

Large horizontal machining center

Large-torque spindle: 8,000min -1Max. spindle torque: 1,009N・mMax. workpiece range: Φ 3,200 x 2,200mm
High-rigidity quill spindle: Φ 150mm quill, Φ 200mm high-rigidity bearing

6JTEKT Corporation WEB site
https://www.jtekt.co.jp/e/JTEKT Bearing WEB site

JTEKT Overseas hubs

https://koyo.jtekt.co.jp/en/

https://www.jtekt.co.jp/e/company/global.html

The contents of this catalog are subject to change without prior notice. Every possible
effort has been made to ensure that the data herein is correct; however, JTEKT cannot
assume responsibility for any errors or omissions.

Reproduction of this catalog without
written consent is strictly prohibited.

CAT. NO. B1002E-4-A

Printed in Japan 16.11- 5BCH（ 08.07）