OUTLOOKTechnical Trends and Vision for Industrial Bearings and Units— Activities Relating to the Shift from "Mono" to "Koto" —T. ADACHI

In the industrial field, there is a need to tailor product development and activities to each specific industry due tothe differences in usage environment, usage conditions and required functions. Furthermore, recently the demand
for not only "mono" (product value), but also "koto" (the value obtained by using a product - i.e. "added value")
has intensified.
This report introduces the future trend of development for steel production equipment, agricultural andconstruction machinery, machine tool spindles and printing machinery, as well as our activities relating to mono
and koto.
Key Words: industrial bearing, bearing technology, mono, koto, universal joint, traction drive

1. Introduction
In recent years, activities to migrate from “mono ”
to “koto ” are accelerating. We have entered an age
where we cannot earn our customers’ satisfaction bysimply providing products (“mono”), and rather than thefunctional value of “mono ”, we must instead offer “koto ”- value obtainable through using a product. In the past,
it sufficed if bearings could rotate for a long period oftime without breaking, however it has become difficult
to offer customers originality with that alone, and thecommoditization of “mono ” is progressing. Originality in“koto ” aspects will become of increasing importantancemoving forward. In addition, the rapid progress of IoT
is accelerating the speed of “koto ” development. JTEKT
is pushing ahead with “koto ” aspects of failure detection
through the visualization of bearing condition, andoptimizing machining conditions through visualization ofmachining status.
Furthermore, in regards to steel production equipment,
large agricultural/construction vehicles, etc., a reduction*of life cycle cost (LCC) has become a key activities toimproving business profitability, and efforts toward both“mono ” and “koto ” aspects are necessary.
This report introduces the technical trends of “mono ”
and “koto ” regarding the rolling bearings which are majormechanical elements supporting the rotating axes ofsteel production equipment, agricultural and construction
machinery, machine tool spindles and industrial fields ofprinting machinery, and also regarding the traction drive
units which are no-backlash reduction gears. This report
also introduces examples of JTEKT’s relevant activities.

8* The total required running costs throughout all
the processes after purchase of a vehicle; namely
maintenance, management and disposal.

2. Trends of Industrial Bearings & Units
The operating environments, operating conditions andrequired functions of bearings and units differ dependingon the industrial type, therefore product development
and activities must be tailored to the respective domain.
Table 1 shows the requirements relating to “mono” and“koto ” by industry type. First, in order to respond to“mono ” requirements, there is a need for technologicaldevelopments in the areas of design, material, heat
treatment, surface treatment, lubrication, machining,
1)
etc. In addition, to respond to “koto ” requirements, thevisualization of bearing condition, in other words sensing
technology, will become important. JTEKT is pushingahead with the failure detection/prediction through2)
visualization of bearing condition (sensing) . Moreover,bearings are subjected to all external loads, therefore are
the most affected when abnormal load occurs. By sensing
bearing load condition, we believe it is possible to detect
abnormal operation and abnormal work. In other words,
we believe it is possible to perform equipment diagnosis
through the visualization of bearing condition. Figure 1
shows a conceptual image of this. Achieving this would
require further improvements in experimental technology,
analysis technology and sensing technology.
Below is an introduction of our activities for eachapplication, as well as the development trends for futureindustrial bearing products, as per Fig. 2. Figure 2 shows

JTEKT ENGINEERING JOURNAL English Edition No. 1016E (2019)

−Technical Trends and Vision for Industrial Bearings and Units — Initiatives Relating to the Shift from "Mono" to "Koto" — −that not only “mono ” such as long life, high robustness,high-speed, low-temperature-rise, sensing and so on but
also the development of “koto ” is important.

Bearing

Equipment

Improved bearing robustness
Improved bearing performance

Improved equipment
performance“ Mono ” aspects

Equipment diagnosis through bearing sensing
Various sensing technology(Displacement, load, temperature, vibration, etc.)

Table 1 Requirements relating to product function (mono)
and added value (koto) by industry type
Industry type

Mono

Koto

(product value)(value obtained by using a product)

Steel

Durability in harsh

production

environments such as highequipment

temperature, water and scale

Agricultural/
construction
machinery
Machine tools

environments“ Koto ” aspects

Failure detection/prediction

Fig. 1 Conceptual image for control of equipment withbearing sensing

Failure detection/prediction
Design considering repairs

3. Development of Contributing
Technologies to the Stabilization of
Steel Production Equipment Operation(LCC reduction)

Supports ultra-high-speed,

High-accuracy, high-eﬃciency

high-rigidity

machining

Reduced rotational

Printing
machinery'21

Robustness in all work

unevenness of rotating drum,

Preventive maintenance
Equipment failure detection/prediction

Preventive maintenanceBearing failure detection/prediction

Steel production equipment must operate in extremely
harsh environments exposed to high temperature,
water and scale. The bearings used in steel production
equipment must also be capable of supporting heavyloads and high-speed rotation, and not only support by
the bearing itself, but also support through integration
with peripheral parts. Figure 3 shows the various bearing
failure types. Figures 4 and 5 show examples of the
JTEKT HYPER STRONG (JHS) as bearings supporting
operation in harsh environments.

New development area

quietness

Heavy Indu
stry
Steel production/Wind po
wer generation☆Sensing for wind turbine main shaft bearings

Agr

icul

tura

l/Co

ns

truc
☆Operation monitors for Wind turbines'20 ☆Long life bearing for windtion
mac☆High-performance
drive
shaftsturbine gear boxes ☆Anti-wear technology for wind turbines

hin

Ind

ust

SBB: Deep groove ball bearing
ACB: Angular contact ball bearing
CRB: Cylindrical roller bearing
TRB: Tapered roller bearing
SRB: Spherical roller bearing
NRB: Needle roller bearing
TDU: Traction drive unitnisio SEVX
rech P on/E
Hig ecisi
r
hp
Hig

ery/
r
☆Sensing of universal ☆Ultra-large-size SRB ☆High-performanceRai yslewing rim bearings for ☆High-robustness TRB
for wind turbine
lwa
joint for rolling mills
ys/Atunneling-boring machinemain shafts
ircra☆High-performance bearings for continuous castings☆Unit products☆Long-life NRB
ft/In
'19
☆Lubricant for wind turbines☆High-durability drive shafts
dus
☆New
trial
☆Axle bearings☆Surface
treatmentforwind
turbines☆Low-temperature-rise,carburizing material
macwith new sensor☆High-performance
TDU
hine
low-friction-torque TRB☆Wear resistant materialry★Large-size SRB for wind turbine main shafts☆Axle bearings with sensor★Load sensing★Long-life material☆Long-life bearings for traction motors★Increased rated load
☆Products/technologies
of radial roller bearings
contributing to remanufacturing ☆New engine bearings'18 ★O/A lubricant systems★High-precision TDU☆High-performance ☆Vacuum carburizing★UJ high-sealing oil seals
auxiliary drive shafts ☆High-speed axle bearings (Ⅱ) ☆New★High-speed high-sealing oil seals
aerospace bearings★Miniature one-way clutches with low drag torque ★High-speed axle
★UJ with RFID tag☆Low-temperature-rise, low-friction- ☆Spindle units with
Bearings (Ⅰ)★Ultra-small TRB
micro-lubrication
unit
torque bearings for drive units'17☆High-speed long-life material ☆Spindle units★Bearing testing ★Ultra-thin SBB for reduction gears
machine for steel
with sensor★Low-temperature-rise
ACB
SBB
for
motors★High-performance
production☆Next generation corrosion-resistant bearings★Engine bearings
Large Size Bearing Engineering Development Center★High-rigidity high-speed CRB☆Ultra-high-temperature bearings (Ⅱ)'16★CRB with PPS cage
★Rigidity measurement systems★
★High-performance TRB☆Ultra-high-temperature bearings (Ⅰ)★Corrosion Guard ★New Clean Pro bearings★JHS high-performanceSRB
Pro Bearing☆High-speed long-life ACB★Ultra-high speed High Ability bearings ★New ceramic bearings
'16

'17

'18

'19

'20

'21
★: Developed

Fig. 2 Trends of industrial bearing development

JTEKT ENGINEERING JOURNAL English Edition No. 1016E (2019)9

−Technical Trends and Vision for Industrial Bearings and Units — Initiatives Relating to the Shift from "Mono" to "Koto" — −Figure 4 shows a sealed-type, four-row tapered roller
roll neck bearing for rolling mill (JHS520). This bearing
has excellent sealing performance, speed and load
resistance. Figure 5 shows a back-up roll bearing for
multi-roll mill (JHS210). This bearing has excellent load
resistance and robustness even when operating in diluted3)-5)lubricant .
High-speed rotation, heavy load

Penetration of rolling mill coolant and scale

Rolling fatigue of material Decrease in strength of lubricant film
Raceway wear
Internal-originating flaking

Rust

Figure 6 shows a bearing test rig for steelmaking
equipment, Fig. 7 shows a summary of the measurement
method for rolling element load, and Fig. 8 shows acomparison of measured values for rolling element load
and FEM analysis values. The measurement results
confirm that the rolling element load distribution has two
peaks due to the impact of housing rigidity, moreover it isclear that there is good consistency with the FEM analysis
values. Using this method, JTEKT performs measurementof radial load for roll neck bearings.

Table 2 Measurement method for rolling element load

Surface-originating flaking

Measurement
Cracksitem

Radial bearings for work rolls

Thrust bearings for work rolls

Rolling element load←

Radial load

Thrust load

(conversion from rolling(conversion from rolling

element load)

element load)

Fig. 3 Bearing failure types3)-5)
Required item
Gauge
mounting

Hollow interior diameter ofNotch part of Outer ringrollerposition

Accumulate strain gauge
Measurement output in ultra-small data Take out strain gauge output by
methodloggerwire→ Take out it upon stopping

Fig. 4 Sealed-type four-row tapered roller bearing forroll neck (JHS520)

Fig. 5 Bearing for multi-roll mill backup roll (JHS210)

Sometimes steel production equipment can be
subjected to loads exceeding design specifications, andthis leads to bearing failure. A variety of factors could
cause this, including operating conditions, maintenanceor equipment deterioration. As “koto ” activities, JTEKT
would like to propose optimal design to our customers
through leveraging proprietorial load measurement
and analysis technologies to measure and analyze therelationship of the bearing use conditions with the internalload status and performing equipment diagnosis based on
actual measurements.
Table 2 shows the load measurement method forrolling elements of radial bearings and thrust bearings forwork roll.

10

Fig. 6 Bearing test rig for steelmaking equipment6)
Rolling element (hollow interior)Cage
A view

Strain gauge
Logger holder

Ultra-small
data logger
A view: logger photoFig. 7 Summary of measurement method of rolling element
load

JTEKT ENGINEERING JOURNAL English Edition No. 1016E (2019)

−Technical Trends and Vision for Industrial Bearings and Units — Initiatives Relating to the Shift from "Mono" to "Koto" — −Moreover, in regards to universal joints for rolling millroll drive (UJ, Fig. 9), JTEKT proposes a repair for UJ*2
and a method for history maintenance by RFID tag tocustomers in order to reduce LCC. Figure 10 shows a UJ
repair system chart.
We wish to contribute to the stable operation of steel
production equipment through these “mono ” and “koto ”
activities.
*2 A system for the non-contact reading/writing of data
recorded within RF tags using electromagnetic waves

FEM analysis value (bearing + bearing housing)
Simple analysis(bearing only)

Measured value

Roller load, kN

300

200

100
0

4. Contributing Technologies to Reduce
the LCC of Agricultural/Construction
Machinery

0

90
180
270
Circumferential position, °360

Fig. 8 Comparison between measured and analysis value ofrolling element load

LCC is an important indicator for a user whenpurchasing agricultural/construction machinery (vehicles).
For this reason, vehicle manufacturers are exerting efforts
in development, proposals and services to reduce LCC.
JTEKT is developing technologies and services that cancontribute to reduce LCC by focusing on six keywords
and experimental analysis technology.
Figure 11 shows the needs of agricultural/construction
vehicles and JTEKT’s development keywords.

CustomerFig. 9 Universal joint for rolling mills

Maintenance activities

Inspection/repair

Sudden failure response

Productivity improvement
activities

Increased rolling load

Operabillty improvement

Stable operation, reduced maintenance cost, efficient maintenance work
Inspection

Equipment
introduction

Operation

Inspection

Operation

Operation

Technological support for stable operation
Proposal of an efficient maintenance cycle

Provision of maintenance technologies

JTEKT◎Proposal of daily inspection items and inspection repair cycle◎Technical proposals for sharing drive shaft usage status◎Minimization of sudden costs through proposing periodic repairs
Proposal of high-functionality items◎Presentation of drive shaft technologies◎Trouble shooting◎Maintenance attendance
Added value products◎Proposal for longer life and increased strength・Varnishing
・Varying-diameter rollers
・Bolt rolling, etc.
◎Improved corrosion resistance・Tungsten carbide spraying ・SUS build-up welding, etc.

◎Hyper coupling◎History maintenance by RFID tag

Fig. 10 UJ repair system chart

JTEKT ENGINEERING JOURNAL English Edition No. 1016E (2019)11

−Technical Trends and Vision for Industrial Bearings and Units — Initiatives Relating to the Shift from "Mono" to "Koto" — −Needs

OthersDevelopment keywords

Assembly-related
damageSeizureMaterial & Heat treatment, surface
treatment, optimal design, crowning
optimization, long-interval greasing
propeller shaft, high-strength cross pin & spline②High-strength design
High-speed
response

Race guide cage bearing, analysis technologies③Low-torque, low-temperature-rise
LFT bearings, fluid analysis & flow control

Low-fuel
consumption④Support for electrification
Motor bearing, capacitor⑤Maintenance-free
Low cost

Condition
monitoring

Shift to resin cages, creep
wear-free bearings, support
for remanufacturing

Experimental analysis technologies①Longer life/downsizing
Compact/
high-strength“Mono” aspects

Stressconcentration(large misalignmentor large load)

Bearing
housing
deformation

According to JTEKT’s investigation
Foreign matter

Lubrication-related(wear, seizure, etc.)

Longer life material, heat treatment technologies“Koto” aspects⑥Failure prediction

Provision of sensing & monitoring technologies
Fatigue analysis, CAE, evaluation

Fig. 11 Agricultural and construction machinery need and
JTEKT㩾s development keywords

Moreover, Fig. 12 shows the failure modes ofbearings used in agricultural and construction machinery(according to analyses of bearings returned to JTEKT) as
well as supporting technologies. 75% of all failures arecaused by either edge stress due to large misalignment orlarge load, or inappropriate lubrication. An important partof helping to solve these issues are “mono” activities ofdeveloping products focused on ①longer life/downsizing,②high-strength design, ③low-torque, low-temperaturerise, etc. as well as optimization of internal specifications
through analysis considering operating conditions
and the rigidity of peripheral parts. These activities
directly contribute to better vehicle performance, higher
robustness and higher fuel efficiency. Moreover, ④technologies supporting electrification are also ofimportance in regards to EV shift of vehicle.

Design optimization
Analysis
Bearing typeInternal design
Raceway profile

Low-temperature-rise, low-torqueFig. 12 Failure mode analysis (as investigated by JTEKT) ofagricultural and construction machinery bearings andbearing support technology“Koto ” aspects of ⑤maintenance-free technologies
and ⑥failure prediction technologies do not directly
contribute to improved vehicle performance, etc. however
are believed to significantly contribute to reducing thenumber of man-hours involved in disassembly workand part repair costs through technologies preventing
damage (wear) to the shaft and housing, which arebearing peripheral parts, as well as through developmentof easy-to-disassemble bearings. In regards to ⑥
failure prediction technologies, Fig. 13 shows JTEKT’sconceptual image for vehicle condition monitoring. By
combining the sensing technologies currently used on
vehicles with JTEKT’s bearing sensing technologies,
customers can not only appropriately appraise the timingof vehicle overhauls and improve operating rate, but also
reduce maintenance costs through failure prediction.
This makes it possible to reduce LCC. Moreover, with
optimized bearing design through grasping the status on
actual equipment, it is also possible to shorten the overallvehicle development period, etc.

JTEKT’s technologies

Agricultural/construction machinery

Bearing sensing technologies
・Rolling element load measurement technology
・Fatigue analysis
・Lubricant deterioration analysis
・Various measurement technologies(vibration, temperature)

Grasp ofactual operating
environments

Customer data
・Torque・Temperature
・Rotational speed
・Operating time：：

Grasp of overhaul timing,
failure prediction, optimized design

Reduction of life cycle cost

Fig. 13 Conceptual image for vehicle status monitoring

12

JTEKT ENGINEERING JOURNAL English Edition No. 1016E (2019)

−Technical Trends and Vision for Industrial Bearings and Units — Initiatives Relating to the Shift from "Mono" to "Koto" — −JTEKT wishes to contribute to reducing vehicle LCC
through these “mono ” and “koto ” activities.

5. Activities for High-Performance
Bearings for Machine Tool Spindles
Each year, the demands placed on machine tools are
becoming increasingly stringent, and consumers areseeking even higher speed, higher rigidity and lower
temperature rise. In recent years, there has been agrowing need for combined processing machines from theperspective of high-efficiency machining, therefore themarket demands that equipment offers both high-speed
and high-rigidity. Moreover, out of the two lubrication
methods, grease and oil-air, the latter is adopted inhigh-speed regions, however from the perspective ofprotecting the environment against the negative impactof oil scattering, there is a growing need to expand the7), 8)
application of grease lubricant .
The performance of spindle bearings used in thespindle unit plays an extremely important role in highspeed performance. At JTEKT, we have achieved evengreater high-speed in our cylindrical roller bearing withhigh rigidity, low temperature rise and grease lubrication
are used in lathes, which require high-rigidity (Fig. 14) as
well as our angular ball bearing with low temperature riseand grease lubrication (Fig. 15). We are also expanding
the application of grease lubricant, and these efforts arecontributing to produce more eco-friendly machine tools.
Moreover, even in regards to machine tools, JTEKT
exerts efforts for the visualization of machining
conditions, which is “koto ” aspects, in order to contributeto high-accuracy and high-efficiency machining.
The rigidity of the spindle unit, which greatly affects
workpiece machining accuracy, is affected itself by
bearing precompression, rotational speed, temperaturerise, spindle posture, etc., therefore, conventionally,
dynamic measurement was difficult. Here, we’d like tointroduce JTEKT’s recent activities; the development of a
dynamic rigidity measurement system.
Figure 16 shows a schematic of a dynamic rigidity
measurement system. This system uses a vibrator
9)
adopting magnetic bearing technology to vibrate thearbor mounted on the spindle at different frequencies
to detect the displacement at that time using a sensor.
Figure 17 shows an example of dynamic rigidity−1
measurement with a rotational speed of 5 000 min , andwhen the spindle is vibrated in a radial direction. The
horizontal axis of the graph shows input frequency, whilethe vertical axis shows dimensionless quantity responding
to rigidity, and was able to confirm that rigidity decreases
when frequency is around 900 Hz. JTEKT aims to use
these results to both enable optimization of machining
conditions and bearing specifications and achieve
development of status monitoring technology for thespindle unit in the future.

Spindleshaft end

Radial exciter
Axial exciter
Arbor

Dynamic rigidity
measurement system

Fig. 14 Cylindrical roller bearing with high rigidity, lowtemperature rise and grease lubrication

Fig. 16 Schematic of a dynamic rigidity measurement system
1.E+0.1

DSP Unit

1.E+00

Bearing: 7916C-5
Boundary dimensions: u80mm×u110mm×16mm(Bore Dia. × Outside Dia. × Width)
Rotational speed: 5 000min−1
Spindle position: horizontal

1.E-01

1.E-02

1.E-03
1

10

100

1 000

10 000Frequency, Hz

Fig. 15 Angular ball bearing with low temperature rise andgrease lubrication

JTEKT ENGINEERING JOURNAL English Edition No. 1016E (2019)

Fig. 17 Outline of dynamic rigidity measurement system13

−Technical Trends and Vision for Industrial Bearings and Units — Initiatives Relating to the Shift from "Mono" to "Koto" — −As the measurement method, we used the same stepping
motor and measured noise pressure while continuously
increasing rotational speed, then performed frequency
analysis. The result of this measurement showed that,while rotational noise still existed in the drive motorof the traction drive unit, the noise that had occurredon the planetary gear in a high number of degrees had
disappeared. Conventionally, traction drive units wereprimarily only used in applications which benefits fromits feature of having extremely minimal rotational speed
unevenness, however in recent years, traction drive units
are being used for new applications focused on quietness,for example, there are an increasing number of cases
where their application is being considered in devices forinvestigating natural environments and animal ecology.
Through application in these new fields, JTEKT wishes towork on the development of new “koto ” aspects.

6. Higher Performance Traction Drive
Units for Printing Machinery
The traction drive unit is a power transmission device
using the rolling contact of rotating bodies, and has
been used for some time as a smooth, play-free gearbox.
In terms of smooth power transmission, there are nomechanisms that surpass the quality traction drive offers,
and it is still used for printing machinery, however now
there are demands for further reduction of rotation speed
unevenness and longer life. Figure 18 shows the planetaryroller-type traction drive unit used in printing machinery.
This drive unit is comprised of a high-accuracy, highstrength roller and was developed by JTEKT utilizing
our bearing core technology accumulated over many long10), 11). Its features are extremely minimal rotational
years
speed unevenness, no backlash, and excellent quietness
due to no vibration or noise caused by gear meshing.
Figure 19 shows noise comparison results of a planetary
gear versus a traction drive unit.

Bearing or bushing

Apart from the content introduced this time, JTEKT
will promote product development responding tocustomers’ needs and problems for a broad range ofindustries, including power generation equipment, rollingstock, transportation machinery and tunneling-boringmachine, as well as further strengthen “koto ” activities.
So that our customers will ultimately think “I’m so glad
because I chose JTEKT”, we will continue offering No.1
& Only One products and technologies, and contributing
to the stable operation of equipment and vehicles as well
as LCC reduction.

Output side
(revolution of planetary roller)

Input side(sun shaft)

Sun shaft

7. Conclusion

Planetary roller*1 JHS (JTEKT HYPER STRONG) is a registeredtrademark of JTEKT Corporation.
*2 LFT is a registered trademark of JTEKT Corporation.

Stationary ring
Lubrication:
Traction grease

Fig. 18 Structure of a planetary-type traction drive unit

Gear noise
disappearance

40

1k

30
Motor noise

500

20

Rotational speed, min−1

1.5 k

52
50

2k
Gear noise
disappearance
1.5 k

40

1k

30
Motor noise

500

20

14
400

1k

1.5 k
2k
Frequency, Hz〈Planetary gear〉

2.5 k

Sound pressure, dB

52
50

Gear noiseSound pressure, dB

Rotational speed, min−1

2k

14
400

1k

1.5 k
2k
Frequency, Hz

2.5 k〈Traction drive unit〉

Fig. 19 Noise comparison results of a planetary gear versus a traction drive unit

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JTEKT ENGINEERING JOURNAL English Edition No. 1016E (2019)

−Technical Trends and Vision for Industrial Bearings and Units — Initiatives Relating to the Shift from "Mono" to "Koto" — −References
1)

K . H AYA S H I DA , H . M AT S U YA M A : J T E K T
ENGINEERING JOURNAL, No. 1015E (2018) 17.
2) R. HOSAKA, S. MATSUDA: JTEKT ENGINEERINGJOURNAL, No. 1012E (2015) 32.
3) R. HOSAKA, N. YASUDA: JTEKT ENGINEERINGJOURNAL, No. 1004E (2008) 42.
4) J. KUBO, M. KAWATA: JTEKT ENGINEERINGJOURNAL, No. 1012E (2015) 43.
5) JTEKT CORPORATION: Ball & Roller Bearings, CAT.
No. B2001E-7 (2017) A152.
6) JTEKT CORPORATION: JTEKT ENGINEERINGJOURNAL, No. 1012 (2014) 114 (in Japanese).
7) T. MURAKI, H. YAMAMOTO: Current State andOutlook of the Multi-tasking Machine, Journal of theJapan Society for Precision Engineering, vol. 78, No. 9(2012) 740 (in Japanese).
8) JTEKT CORPORATION: Precision Ball & Roller
Bearings for Machine Tools, CAT. No. B2005E-3 (2016),
35.
9) H.UEYAMA: Koyo Engineering Journal, No. 163E
(2003) 24.
10) R. NAKATA: Koyo Engineering Journal , No. 149 (1996)
31 (in Japanese).
11) A. KAWANO: Koyo Engineering Journal, No. 165E
(2004) 59.

T. ADACHI**JTEKT ENGINEERING JOURNAL English Edition No. 1016E (2019)

Industrial Machinery Application Engineering Dept.,
Bearing Operations Headquarters

15