Prospects

Efforts for Service & Solution Business in NTN

Hiroyuki KUREBAYASHI*
Rolling bearings are fundamental mechanical parts working in various
equipment that support our life activities. The failures on mechanical
Bearing
parts in the industrial equipment cause a stop of the equipment and
life
cycle
Bearing
supply management
induce a considerable amount of profit loss. It is important to monitor
service
Condition
the condition of temperature or vibration around the bearings, inmonitoring
order to prevent the unexpected stop of the equipment. NTN develops
bearings with sensing functions and provides condition monitoring service of the bearings. We are willing toprovide the service & solution, which is valuable to solve the customerʼs problems by using the sensing data.
Maintenance

1. Introduction
Machinery and equipment that have rotating
mechanisms support the abundant lives of people
today. Many of the machines and equipment used to
manufacture transport machinery such as automobiles
and railroads, as well as air-conditioning equipment
and household electrical appliances are equippedwith rotating mechanisms. Rolling bearings (hereafter,
bearings) are one of the major components used inthese rotating mechanisms. Bearings must rotatesmoothly while supporting the rotating shaft and beable to operate in a stable manner for long periods oftime. Although improvements in bearing performancecontinue, it is said that bearings are the cause of 30 %of all machinery and equipment failures1).
Since profit is lost when equipment stops due todefects in machine parts at the production site, it isimportant to monitor the temperature and vibration
around the bearing to prevent defects from occurring.
Furthermore, in the automotive sector, bearing
condition monitoring will become essential as growth
in autonomous driving results in people moving fromownership of automobiles to sharing them, in addition
to the development of infrastructure to support
autonomous vehicles.
As mentioned above, it is necessary to develop
a method (providing services) to use bearings ina stable manner for extended periods of time, notjust develop technology (providing products) forthe bearings themselves. In response to this, NTN
provides solutions that combine both products andservices that focus on bearing technology:• High-performance products that integrate sensing
functions with bearings (products)• Services that provide users with informationsuch as bearing condition diagnosis, appropriate
methods of use, and replacement periods (services)
Here, I will introduce an overview of the service andsolution business that NTN is working on and discuss
the future prospects. More detailed information
about the technology and applicable products will be

introduced separately in other articles in this technicalreview.

2. Sensing around the bearing
NTN has developed a bearing with a sensor thatcombines bearing and sensing functions with the aimof responding to the following customer needs:(1) Integrated multi-functions for bearings(2) Improved reliability for machinery, equipment,
and parts as well as support for maintenance(1) Implementation within compact machines
such as motors and pumps. Incorporating a sensing
function in the bearing provides an effective methodof saving space and reducing the person-hours for
assembly, etc. Sensing functions are used to measuresuch things as the rotational speed, rotational angle,
and load around the bearing, and are used to control
the operation of machinery.
(2) Implementation within large equipment thatmust operate in a stable manner and run for longconsecutive periods of time. Sensors embedded
into the bearing are used to monitor the bearingʼsoperating conditions, and to provide information
about bearing condition diagnosis such as whether
it is damaged. This aims to prevent unforeseen
problems and minimize stoppage time due to failure.
To diagnose the condition of a bearing, it is necessary
to sense such factors as its temperature, vibration(noise) and lubrication conditions (oil film thickness,grease degradation, foreign object contamination).
If production equipment or infrastructure-related
equipment suddenly stops operating, this will have asignificant impact on business operators and society.
Therefore, there is a strong demand in these sectors
for a bearing that will not fail, or at the very least anunderstanding of a suitable replacement period. NTN
provides technical services that achieve a high levelof accuracy in predicting and detecting when a failure
will occur. These services prove useful to customers inpreventing equipment-related problems and production
downtime.

* Deputy Corporate General Manager, Industrial Business Headquarters

NTN TECHNICAL REVIEW No.89

23

Efforts for Service & Solution Business in NTN

3.1 Rotation sensor bearing
The rotation sensor bearing is constructed byincorporating a magnetic sensor and magnetic
encoder in the bearing as shown in Fig. 1, and NTN
has created a lineup of several standard deep grooveball bearing numbers. Since a magnetic sensor isused, it is resistant to contamination compared withgeneral optical sensors and can also be used in hightemperature environments. This type of bearing isused to control the drive motor on forklifts and forwheel slip prevention control.

of accuracy. For example, when passing over a sectionof asphalt road covered in gravel, the rotational speed
changes spectrum varies2) as shown in Fig. 3. Using
this type of high-resolution signal can further enhance
the functionality of automotive control.
400
350

Frequency Hz

3. Implementation example of a bearing
with a sensor

300

Road covered in fine gravel

250
200
150
100
50
0
0

Magnetic sensor(Hall IC)

50

100

150

200

Run m

250

300

Fig. 3 Variance in speed change spectrum while driving2)
Sensor basic configuration
Magnetic
field
Bz

Hall IC
Magnetic encoder(NS-pole alternating
magnetization)

Fig. 1 Rotation sensor bearing2)
3.2 Automobile wheel speed sensor
A magnetic sensor to detect the wheel speed isfitted onto the bearings of automobile wheels (hubbearings) and used for controlling ABS (anti-lockbraking system). The seal on the hub bearing has abuilt-in rubber magnetization ring, which provides
high durability and prevents deterioration aroundthe wheel over an extended period even in harshenvironments. NTN has also developed the Hub
Bearing with an Integrated High-Resolution Rotation
Sensor2) that uses a magnetic sensor provided with aninterpolation function (Fig. 2).
For drive wheel

3.3 Multi Track Magnetic Ring for absolute angle
sensing
NTN has developed the Multi Track Magnetic
Ring3) as shown in Fig. 4. This magnetic ring is soldas a detection target for use in combination with amagnetic sensor for absolute angle detection. The
magnetic sensorʼs advanced interpolation function
and Multi Track Magnetic Ringʼs highly accurate
magnetic pattern make it possible to detect a single
revolution (360 degrees) with an angle resolutionof over 100 thousand divisions. Since it is magnetic,
it has superior environmental resistance whencompared to optical sensors, and its compact
configuration is suitable for saving space. It is used asa control sensor on robot joints and various types ofmotors.
Sub track (63 polar pairs)
Main track (64 polar pairs)
Rubber magnetic
material

Magnetic sheet is affixed toshow magnetization pattern

For driven wheel(b) Magnetization pattern

Core(a) External appearance

Fig. 2 Hub Bearing with an Integrated High-Resolution
Rotation Sensor2)
Wheel rotation signals include the impact oftire conditions (such as the air pressure) and roadconditions. Analyzing high resolution rotation signals
makes it possible for us to detect the differences intire conditions and road conditions with a greater level

24

NTN TECHNICAL REVIEW No.89(c) Illustrated
magnetization patternFig. 4 Multi Track Magnetic Ring: Radial
magnetization type3)

3.4 Sensor Integrated Bearing Unit for Machine Tool
SpindlesThe main shaft unit on a machine tool must supportcondition monitoring and IoT in addition to having
the fundamental ability of high speed, high rigidity,
and high accuracy, etc. NTN has developed the “Sensor
Integrated Bearing Unit” for Machine Tool Spindles,
which has various sensors integrated into the outerring spacer adjacent to the bearing to monitor theconditions inside the bearing and has a load detection
function and wireless communication function (Fig. 5)4).
These sensors detect deteriorating lubrication
conditions and signs of damage from vibration andtemperature sensing information to prevent defects.
Alternatively, they have been proposed for use inadjusting machining conditions by monitoring suchfactors as forming load and bearing pre-load amount.
Outer ring spacer(Various sensors are integrated)

Spindlebearing

4. Efforts for condition monitoring services
4.1 Trends in condition monitoring
In recent years, the concept of assessment
management, which targets the maintenancemanagement and operation of infrastructure suchas roads and buildings, is also being expanded to themachinery and equipment sector, and extensively
applied to areas from machine condition monitoring topart procurement control. In terms of the equipment
maintenance method, there has been a shift towards
CBM (condition-based maintenance, predictive
maintenance) from the conventional TBM (time-based
maintenance, preventive maintenance) method (Fig. 7).
Under such circumstances, efforts to monitor
bearing conditions during operation, detect signs ofdefects and then provide measures before problems
arise have attracted a great deal of interest.

Spindlebearing

Inner ring
spacerFig. 5 “Sensor Integrated Bearing Unit” for Machine
Tool Spindles4)
3.5 Talking BearingTM
NTN has developed a “Talking BearingTM” as theultimate form of a bearing integrated with sensing
functions (Fig. 6)5). This bearing has the same external
dimensions as a standard number bearing but also
has vibration, temperature, and rotation sensors aswell as a power generator, signal processing circuit
and wireless communication unit incorporated into
the bearing. The bearing generates power as it rotates
and results from sensors are sent wirelessly, allowing
the bearing to “talk” and convey information.
Currently, space is required to incorporate theelectronic circuit and power generator so there is alimit to the viable bearing size. However, the progress
being made in miniaturizing sensor devices andthe improvements in power saving will lead to theimplementation of much smaller diameter bearings
that use this concept in the future.
Electronic circuit board(Includes sensors and wireless device)
Material
to protect
circuitFig. 6 Talking BearingTM

Fig. 7 From time-based maintenance tocondition-based maintenance.
4.2 Introducing a condition monitoring system forfactory equipment
To operate large machinery and equipment,
continuous operation pumps and generators, etc.,
in a stable manner for extended periods of time it isvital to conduct suitable maintenance work based on
bearing condition monitoring, diagnosis technology
and the conditions. At large-scale equipment andimportant production lines, comprehensive condition
monitoring systems are introduced while regularinspection and daily maintenance work is conducted
constantly together with records for operation andmaintenance. In this manner, all companies haveestablished a condition monitoring and operation
management system for their entire factory to prevent
problems with large equipment.
In contrast, operation management is often
conducted individually for each machine when looking
at small-scale equipment. This creates the problem ofmaking it difficult to introduce condition monitoringmachinery and connect it to a unified systemfor operation because factories with small-scaleequipment use a mix of partially optimized systems
throughout the factory.
An IoT platform has been proposed to solve thistype of problem. The IoT platform is introduced toeach piece of equipment and then applications suchas measurement software are run on the equipment

NTN TECHNICAL REVIEW No.89

25

Efforts for Service & Solution Business in NTN
to make it easier for data and communication to besent between equipment as well as stored data to be
managed at a central location and facilitate mutual
use of such stored data.
NTN has developed a bearing diagnostic application(Fig. 8) that runs on Edgecross6), which is an IoT
platform. This application is provided as a condition
monitoring tool that requires no internet connection
or detailed settings7). See the commentary section for
more information about this application.

conditions and maintenance work cannot be
conducted easily. For this reason, remote monitoring
using a condition monitoring system (CMS) is
necessary, and the use of this type of system has
spread throughout Japan.
Mainbearing

Rotor

GearboxGenerator

Nacelle

Blade

Tower

Fig. 10 Large wind turbine structure

Fig. 8 Bearing diagnostic application
4.3 Portable Vibroscope
When personnel regularly take measurements atfixed points on equipment as they patrol and monitor
their worksite where TBM (time-based maintenance)is performed, there is a demand for a measuring
instrument that is easy to carry around and that caneasily record data. The NTN Portable Vibroscope8),
as shown in Fig. 9, is a useful tool for this type of
application.
Personnel can connect the device to a tablet PC ora smartphone, then measure and record vibrations at
the equipment to determine the conditions based on
predefined criteria or analyze condition trends. If theobserved data needs to be analyzed in more detail,a frequency analysis function is used to enable suchthings as coupling damage and bearing damage to bediagnosed.

Plans are underway in Japan to introduce large
wind turbines with the aim of creating offshore windturbine projects in the region of 10 GW by 2030 and
30 to 45 GW by 2040. One of the technical challenges
in this area is reducing the cost of power generation,and targets were indicated to achieve 8 to 9 yen per
kWh using seabed-mounted offshore wind turbines. To
achieve this, significant importance has been placedon reducing the cost of operation and maintenance(O&M), which accounts for 36 % of the lifetime cost ofwind turbines (Fig. 11).

Fig. 11 Lowering the cost of offshore wind turbines(Source: Found in documentation from the
Ministry of Economy, Trade and Industry9))

Fig. 9 NTN Portable Vibroscope
4.4 Trends in condition monitoring with large windturbines
Large wind turbines, as shown in Fig. 10, areinstalled at a height of over 60 meters above groundlevel and are often operated in difficult to accesslocations such as along the coast and in mountainous
areas. Weather conditions can also restrict work on
wind turbines so it is not easy to know the equipment

26

NTN TECHNICAL REVIEW No.89

4.5 Wind DoctorTM, a condition monitoring system
for wind turbines
NTN released Condition Monitoring System (CMS)for Wind Turbines “Wind DoctorTM” for sale in 2012.
Currently, this system is in operation at around 300
wind turbines throughout Japan10) 11). Wind DoctorTM
provides a monitoring service as shown in Fig. 12.
Sensors installed on the wind turbine are used toremotely collect and store data such as vibrations
on a regular basis for monitoring purposes. If an
abnormality or change is detected, the system
will promptly send information to the customer.

Customers using this monitoring service can use
this information for operation management andmaintenance work on their wind turbines.
As discussed above, offshore wind turbines are
more difficult to access than those built on land, andremote condition monitoring of key components suchas bearings is particularly important for offshore windturbines. Furthermore, it is believed necessary to
evolve and support condition monitoring systems sothat they can adapt to the weather conditions uniqueto Japan, such as typhoons and winter storms over
the Sea of Japan, which are said to be the strongest in
the world.
NTN has selected the two projects of “nextgeneration wind turbine technology development”
and “offshore wind turbine operation maintenanceenhanced functionality” for NEDO Green Innovation
Fund Projects12) and started activities on theseprojects from FY202213). These projects promotetechnological research and development fromboth sides of “products” and “services” in terms ofdeveloping improvements for bearings and enhancing
the functionality of CMS.
Data is automaticallycollected

Data is stored,
automatic diagnosis

Monitoring
analysisDatacollection
systemInformation
and results arereported
Assists O&M for wind turbines

Fig. 12 Wind DoctorTM monitoring service

uses observed data from the actual machine and is
working on the continuous operation of this system. At
the same time, we are focusing on developing sensor
devices for collecting sensing information centeredon bearings, as well as providing measurement tools,
which we consider to be especially important.
5.2 Solutions provided by NTN
The following types of information are required byequipment operation sites to monitor the conditions
and sense around the bearing.
(1) The decision about whether operating conditions
are suitable or not(2) The estimated progress of damage if it has
occurredTechnology shown below is required to provide
this information and requires a great deal of timeand effort such as expert level training and much
experience.
• Fundamental knowledge of bearings and condition
diagnosis technology• Sensing technology and signal processing
technology• Technology to automate condition assessment,such as AI diagnosis• Expertise in issues unique to bearings
Business operators who run equipment needcondition diagnosis information for the entire
machine, not just for the bearing condition. Therefore,
comprehensive assessment technology thatincorporates information from around the machineis required. Furthermore, depending on the uniquecharacteristics of the operated equipment, we may
also be able to consider operations that combine
information from a wide range of fields. For example,
we may be able to use various data such as weather
data, financial data, social events, or currency
exchange information and apply it to data analysis
for equipment operation management through tasks
such as considering procurement costs and the timingof repairs.

5. Efforts for the solution business
5.1 Using sensing data
Generally, condition monitoring systems diagnose
equipment conditions using diagnosis parameters
derived from such things as vibration data measured
around bearings. It is possible to calculate many
diagnosis parameters, but it is difficult to selectparameters that are viable for diagnosis because they
are different for each piece of equipment.
If diagnosis parameters have previously been
selected through observation and experience, anda large volume of data has been stored that shows
the relationship between the measured data anddamage, then it is possible to teach an AI system toautomatically select viable diagnosis parameters. Also,
analyzing cases of observed damage and defects canalso improve the design of machinery and equipment
and their operation method. The more we can store
actual data from the machine, the greater we can
improve accuracy in assessing the conditions relating
to the equipment.
NTN continues to build a system that stores andFig. 13 Service & Solution Business in NTN
Many business operators feel it is important tofocus on operation and management that uses
collected data rather than spending the effort tobuild and maintain a monitoring system. As shownin Fig. 13, NTN will continue to develop services
that provide solutions that can be used in business

NTN TECHNICAL REVIEW No.89

27

Efforts for Service & Solution Business in NTN
operations, such as equipment maintenance planning,by extracting information beneficial to the customer
and information required to resolve problems throughactivities such as monitoring the condition of bearings
incorporated in equipment.
5.3 Development of wind turbine maintenance businessIn addition to condition diagnosis based on CMS forwind turbines, NTN is working to optimize operationand maintenance and its use in operation control.
In the long term, we will develop long operating
life bearings by analyzing CMS data and cases ofbearing damage, while promoting the provision of a
total service for aftermarket bearings and inspection
maintenance to reduce O&M costs for offshore windturbines.
In the wind turbine sector, NTN has started
an initiative14) in the maintenance business incollaboration with Hokutaku Co., Ltd. By optimizing
the operation and maintenance of wind turbines
based on CMS information (smart maintenance) andcollaborating on the development and procurement ofbearings, and operation and maintenance services, as
shown in Fig. 14, NTN will achieve bearing life cycle
management and continue to contribute to society.

Data Acquisition System

Wind power Companies

Fig. 14 Bearing life cycle management

6. Summary
NTN not only sells products but also provides
services to resolve customer problems. Efforts inthis area will be focused on developing softwarethat analyzes sensor signals and software that
controls machinery to create new value. Additionally,
we will provide aftermarket bearings and develop
improvements in new bearings based on collected
information and build life cycle management forbearings centered on bearings and their monitoring
information.
In the future, we will build a business model thatuses this big data and promote service and solution
business that will lead to improved NTN brand value.
References
1) Japan Lubricating Oil Society, Lubrication
Management Optimization Promotion
Investigation Report, 1995.
2) Kentaro Nishikawa, Toru Takahashi, C. Duret,
Hub Bearing with an Integrated High-Resolution
Rotation Sensor, NTN TECHNICAL REVIEW,
No.81, (2013)52.

28

NTN TECHNICAL REVIEW No.89

3)

Takashi Koike, Yasuyuki Fukushima, Yusuke
Shibuya, Hiroyoshi Itou, Development of Multi
Track Magnetic Ring for High Accuracy Absolute
Angle Detection, NTN TECHNICAL REVIEW,
No.86, (2018) 45.
4) Shohei Hashizume, Yusuke Shibuya, Daichi
Kondo, Yohei Yamamoto, Hiroyuki Iwanaga,
Development of Sensor Integrated Bearing Unit
for Machine Tool Spindles, NTN TECHNICALREVIEW, No.88, (2020) 33.
5) NTN, Press Release, NTN Develops Sensor
Integrated Bearing “Talking BearingTM”.
https://www.ntn.co.jp/japan/news/new_
products/news202200041.html
6) Edgecross Consortium,
https://www.edgecross.org/
7) NTN, Press Release, Extension on Period toProvide Free Trial Version of Bearing Diagnostic
Application.
https://www.ntn.co.jp/japan/news/new_
products/news202200022.html
8) NTN, Portable Vibroscope, NTN TECHNICALREVIEW, No. 87, (2019) 106.
9) METI, R&D and Public Implementation Plan
Formulated for “Cost Reductions for Offshore
Wind Power Generation” Projects
https://www.meti.go.jp/shingikai/sankoshin/green_
innovation/green_power/pdf/001_04_00.pdf10) Makoto Miyazaki, Wataru Hatakeyama,
Application of Condition Monitoring System(CMS) for Wind Turbines, NTN TECHNICALREVIEW, No.86, (2018) 40.
11) Katsuyoshi Suzuki, Deployment and Improved
Reliability of the Condition Monitoring System forWind Turbines, NTN TECHNICAL REVIEW, No.88,(2020)111.
12) NEDO, Started Green Innovation Fund Project“Offshore Wind Turbine Cost Reduction”.
https://www.nedo.go.jp/news/press/
AA5_101505.html
13) NEDO, Business Overview Documentation of“Green Innovation Fund/Offshore Wind Turbine
Cost Reduction” Project.
https://www.nedo.go.jp/content/100941539.pdf
14) NTN, Press Release, NTN Starts Maintenance
Service for Wind Turbines.
https://www.ntn.co.jp/japan/news/press/
news202200031.html

Photo of author

Hiroyuki KUREBAYASHI
Deputy Corporate
General Manager,
Industrial Business
Headquarters