Rolling Bearings Contribute to the EnvironmentRolling Bearings Contribute to the EnvironmentRolling Bearings Contribute to the EnvironmentRolling Bearings Contribute to the Environment

Japan Bearing Association

Global environment committee

1. Introduction

Environmental problems the world over, beginning with depletion of the ozone layer in the 1980s, have lead to global warming,

stripping of natural resources, toxic waste, and so on. The progress we enjoy now may spell out the ultimate demise of our

very existence as humans in general.

Global environmental issues are related to the activities of every individual. Although not readily apparent, rolling bearings,

being an essential element in various industries, also have an impact on the environment. Originally designed to use less

energy and save natural resources through their entire life, rolling bearings are environmentally friendly and have little

negative impact on the environment.

Specifically, one distinctive feature of bearings is low friction. This contributes to the use of less energy of all rolling areas.

Regarding bearing production, recycled steel from scrap is mostly used for the raw material of bearing steel, and machining

grids. Chips at the production process are also melted and recycled. With these points in mind, we want to discuss and touch

on the topic of the environmentally friendly aspects of rolling bearings.

2. Energy Conservation

Since the industrial revolution, energy consumption has grown significantly. Most energy requirements are filled by the

consumption of fossil fuels, such as petroleum products, and coal. These energy sources are limited, though, and will

eventually be depleted in the future. During the 1970s oil crisis, attention was focused on energy conservation measures,

with the realization that fossil fuels are finite. In the later half of the 1990s, a new theme, the reduction of carbon dioxide,

was proposed with the primary focus on global warming and what industries can do to achieve further savings in energy

utilization.

Rolling bearings, which we produce, play a significant role in energy conservation. This has been our contribution since

ancient times. Once we understood the basic concepts, we were moving hefty objects of wood or stone on rollers. We

learned that this required much less effort than just sliding. We finally understood that using rollers could reduce frictional

resistance, thus contributing to energy conservation. From day one, rolling bearings have been contributing to energy

conservation. Though indirect, the contribution our products make to industries in regards to their energy conservation is

enormous. Since this effect is difficult to measure in numbers, the average person might not be aware of the contributions

bearings make. The loss and waste of energy through frictional resistance of rolling bearings has to be reduced even further

to its barest minimum. Therefore, bearing manufacturers need to increase their efforts to further their contributions to

industries.

Here are some examples of how bearings contribute to energy conservation.

2.1 Energy Conservation by Rolling

The most basic characteristic of rolling bearings is low friction. Compared to sliding bearings, substantial savings in energy

can be attained by replacing sliding bearings with rolling bearings.

2.1.1 Contribution of Automotive Rolling Bearings

Figure 1 shows the torque loss of sliding bearings and rolling bearings. As shown in Figure 1, the torque loss of rolling

bearings is small for the entire range of speed. This clearly indicates that rolling bearings contribute to energy conservation.

For example, if all the automobiles in Japan only used sliding bearings and ran at the speed of 60 km/h, which is the point of

least torque loss difference, the increased amount of fuel consumption would be 480,000 kl (crude oil). The number of

barrels of oil, when stacked one of top of the other, would be 240 times higher than Mt. Everest.

Figure 1 Comparison of energy consumption for vehicles with and without rolling bearings.

2.1.2 Contribution of Rolling Contact for Roller Tappets and Rocker Arms

Originally, the roller in an engine would slide on the cam. Now, many engines use roller tappets that have a hardened steel

roller turning on needle bearings. This reduces friction and improves fuel economy (Figures 2 and 3). For most sedans,

engine rpm is mostly in the low and medium ranges. In these ranges, since the loss of the valve system is relatively high

among entire engine frictional loss, introduction of rolling bearings in valve system has contributed to better fuel economy

(Figure 4).

Figure 2 Design of rocker arms (See Document 1)

Test conditions

Actual engine motoring

Oil temperature: 100°C

Sliding rocker arm

Rolling rocker arm

Runnin

g to

rque (N·m

)

Camshaft speed (rpm)

Conventional rocker arm (Sliding type) Rocker arm with needle bearings

0.0

2.0

4.0

6.0

8.0

0 30 60 90

Car speed (km/h)

Sliding bearings

(Rolling bearings are not used)

Rolling bearings

Energy conservation

by rolling bearingsTorq

ue loss

(N·m

)

Figure 3 Running torque of actual engine head motoring

Figure 4 Improved fuel economy with rocker arms and needle bearings (See Document 1)

2.1.3 Contribution of Automotive Transmission Rolling Bearings

Needle roller bearings are used in transmission gear shafts (Figure 5). In the past, sliding bearings had been used for these

applications. Rolling bearings replaced the sliding bearings with no change to space requirements. Frictional torque has been

reduced by about one-tenth with increased machine and fuel efficiency resulting in greater energy conservation.

Figure 5 Application of rolling bearings in a sedan transmission

2.1.4 Contribution of Fan Motor Miniature Ball Bearings

Let’s compare the consumption of electricity for two 80-mm fan motors, each running at 2,550

miniature ball bearings (Bearing number: 693) and the other incorporates sliding bearings (Sintere

follows:

Miniature ball bearings: 0.9 w

Sliding bearings: 1.2 w

These results show that if 100 million fan motors ran for 8 hours a day, 250 days a year, the tota

be 6 million kw·h/year. If powered by plants using fossil fuels, the reduction in carbon dioxide em

2.2 Energy Conservation by Reducing Torque in Rolling Bearings

In our efforts to further conserve energy, we have made efforts to reduce bearing torque loss.

2.2.1 Contribution of Low-Friction Tapered Roller Bearings

0 1 2 3 4 5 6 7 8 9

Fuel efficiency (%)

100km/h

80km/h

60km/h

40km/h

10-mode fuel consumption

Idling fuel consumption

Fie

ld fuel

R: Radial type

S: Axial type

rpm. One fan incorporates

d metal). The results are as

l energy conservation would

issions would be 5,280 tons.

Tapered roller bearings used in automotive powertrains have rather high frictional resistance compared to other rolling

bearings. The bearing running torque has been reduced 20 to 50% by reducing friction coefficient between the large head of

the roller and the rib surface, and by applying crowning on the outer ring raceway (Figure 6).

Figure 6 Running torque of low-torque tapered roller bearings

2.2.2 Contribution of Power Hand Tool Bearings

Hand tools include tools powered by electric motors, such as grinders, drills, cutters, etc. Figure 7 shows the bearing

application for a grinder. Running conditions for these types of bearings are harsh and require superior wear and corrosion

resistance. Various conditions include operating under high speeds (some tools exceeding 20,000 rpm), and exposure to dust,

water and mist.

Sealed deep-groove ball bearings are most popular for hand tools. If dust or water resistance is required, contact-type seals

are often incorporated.

The very nature of hand tools requires that they are light in weight, have low vibration, and generate as little heat as possible.

These requirements extend directly to the bearings of such tools. In order for the tools to meet user requirements, the

bearings, too, must have low vibration, and generate as little heat as possible (low torque).

Power hand tools that meet the above requirements also require smaller motors resulting in less energy consumption. To

achieve all of these, the following innovations have seen a 50% increase in improvements:

(1) Adoption of low-torque contact seals

(2) Selection and quantity of greases suitable for high speeds

(3) Low torque design of bearing interiors

Figure 7 Bearing arrangements in a power grinder

Bearing bore: ø30, ø50 mm

Axial load: 3.92 kN

Lubricant viscosity: 23.3 mm²/s

Conventional bearings

Improved bearing I

Improved bearing II

Runnin

g to

rque

N·m

Speed (rpm)

2.2.3 Contribution of Seal and Seal Recess Improvements (Standard deep groove ball bearings) for Low Torque Bearings

Running torque has been reduced 20% by redesigning the seal and seal recess of sealed deep groove ball bearings (Figure 8).

Figure 8 Low torque achieved by improvements in the seal recess

The examples and information provided thus far clearly indicate the positive impact that bearings have had on saving natural

resources, and show how bearings can assist various industries in lowering energy consumption. As suppliers of such

bearings, we promise to maintain our endeavor to develop optimum bearings to meet various needs of both industry and the

environment.

3. Saving of Natural Resources

3.1 Light Weight

3.1.1 Streamlining Massive Bulk

In the past era of excess, emphasis was on performance while structural size was ignored. Current trends require that we

review the past era of waste and excess. To meet modern requirements of efficiency, reliable design and production

technologies are indispensable.

In comparison to the overall size of the machine or equipment, bearing weight or size is not so great. However, production of

compact and light bearings, while maintaining reliability, allows for more freedom in end-product design, substantially

contributes to making machines and equipment more lightweight.

Figure 9 shows the axle bearings of Japan’s shinkansen “bullet” train. Forty years ago, the 0-series model (Maximum

speed: 250 km) utilized an axle bearing that consisted of one double-row cylindrical roller bearing for radial load, and one

deep groove ball bearing for axial load. A single axle bearing weighed in at 75 kg. Then, 30 years later, the 300-series model

(Maximum speed: 300 km) was introduced. Bearing mass was drastically reduced to only 31 kg by utilizing improved

materials and by design reviews. The most obvious change was in eliminating the deep groove ball bearing for axial load and

applying all the axle load to double-row cylindrical roller bearings instead. Bearing mass of the latest mode, the 700-series,

is only 25 kg. Since each coach is installed with 8 sets of bearings, coach mass is directly reduced by 400 kg (75 – 25) × 8).

Furthermore, bearing size has also been reduced. The lighter and smaller bearings allow for even greater energy

conservation of the bullet train.

0-series (1964) 300-series (1992) 700-series (1999)

Mass 75 kg 31 kg 25 kg

φ12

5

φ13

0

φ12

0

φ12

0

130

155165

170

210

215

55

φ26

0

φ28

0

φ23

0

φ22

0

Conventional New 0

100

Ball bearing: 6908, both sides sealed

Inner ring rotation: n = 1800 rpm

Runnin

g to

rque ( %

)

Conventional New

Figure 9 Evolution of axle bearings for Japanese shinkansen “bullet” trains

Figure 10 provides an example of a hard disk drive (HDD) used for data storage devices in personal computers. During the

1970s, HDDs grew in popularity as data storage devices for large computers. Disk diameter was larger than 10 inches, and

the spindle was supported by precision angular contact ball bearings of around 40 mm bores. Recently, the density of

personal computer HDDs has drastically increased. Disk diameter was reduced to 3.5 inches, and then 2.5 inches and

1.8-inch disks are appeared. To meet the demand for reduced disk sizes, bearings installed into the disk support became

small, extra small ball, and finally miniature. Now, miniature ball bearings are industry standard. High precision bearings have

helped make high-density, compact, and high-speed HDDs a reality. The dynamic running accuracy (NRRO: non-repetitive

runout) of support bearings for HDDs has improved to the 0.01 µm-level (Figure 11)

Figure 10 Cross-sectional view of

Figure 11 Required NRRO

3.1.2 Integration or Built-in Surrounding Parts (Unificat

The amount of space used by a part, its mass, or the n

unifying the bearings and other surrounding component

conservation.

Figure 12 shows an example of automotive wheel hub un

ball bearings, were used. Specifically, automakers assem

configuration evolved to double-row angular contact ba

being integrated into the surrounding components. Hub

lighter weight contributes to improved fuel economy, an

for automakers. Moreover, variations in tightening torqu

accurate. Overall performance, quality, stability, and s

S

Bearing

NR

RO

, µm

Year

Miniature ball bearings

a HDD spindle motor

for HDD spindle motors and bearings

ion)

umber of related components, can be reduced by integrating or

s. Direct use of the mating shafts can result in resource and energy

it. 40 years ago, a pair of tapered roller bearings, or angular contact

bled the bearings with the housing and the hub shaft. The original

ll bearings. With the second and third generations, bearings were

mass is reduced by 20% owing to the reduction of components. The

d integration of hub components contributes to labor cost savings

e at the automaker’s bearing assembly line is simplified and more

afety of the vehicles are enhanced.

pindle motor

Second generation Third generation Integrated

+ constant velocity joint + constant velocity joint constant

velocity joint

Figure 12 Evolution of wheel hub unit bearings

Figure 13 shows an example of needle roller bearings. Needle roller bearings have less cross-section height compared to

cylindrical roller bearings and are more lightweight. The example shows installation of needle rollers with a cage and

drawn-cup needle roller bearings. By utilizing the housing or shaft of mating machines as a bearing ring, these bearings can

reduce bearing height.

Figure 13 Needle roller bearings in a planetary gear reducer

3.1.3 Thin Cross-section of Standard Bearings

Deep groove ball bearings, which are easy to use, are most common for the 60, 62 and 63 series. Ever since bearing

manufacturers started producing the 67 series, in addition to the 68 and 69 series of which cross-section is small, users can

easily procure thin cross-section bearings.

Thin cross-section bearings, as shown in Figure 14, have a smaller outside diameter and width if the bore diameter is the

same. Therefore, they are more lightweight and compact.

K: Needle rollers with cage and rollers

T: Drawn-cup needle roller bearing

64 series

63 series62 series60 series

69 series

68 series

67 series

Figure 14 Comparison of cross sections of bearing series

3.1.4 Adoption of Pressed Steel

Bearing rings can be made of pressed steel if the application is limited and the pressed part can fulfill the reliability required

for bearings. For these types of bearings, the rings are thinner and the bearing mass can be reduced.

Figure 15 shows an automotive clutch release bearing whose rings are replaced with pressed rings. Mass reduction is about

10%.

Conventional (interchangeable) Pressed steel

(Machined rings) (Pressed rings)

Figure 15 Clutch release bearings

3.2 Long Life

Bearing manufacturers have tried to improve and develop bearing materials through cooperative research with steel

manufacturers to extend bearing life and improve reliability. Research includes reduction of impurities and oxygen in steel,

special materials for special applications, development of special heat treatment, and surface modification.

The results are lightweight and long-life bearings that contribute to energy conservation. Further efforts for longer life are

continuously being promoted to support all industries in the future. The following are examples contributing to resource

conservation.

3.2.1 Longer Life by Improving Purity of Bearing Steel

To meet the requirements of lightweight and fuel efficient cars, maintenance-free steel mill equipment, and bullet train

related equipment, bearing running conditions have been severe. The demand for longer life is never-ending. By the early

90s, steel life was seven times of that from the late 60s. The purity of steel was improved by reducing oxygen content and

non-metallic incursions (oxide impurity which is origin of fatigue flaking) in bearing steel (SUJ steel: equivalent to AISI

52100) (Figures 16 and 17).

LD

intro-

duced

Oxy

gen in s

teel,

ppm

LD: Ladle vacuum degassing

RH: RH vacuum degassing

LF: Ladle refining

CC: Continuous casting

EBT: Eccentric bottom tapping

RH introduced

Years

LF introduced

EBT introduced

CC introduced

Figure 16 Reduction of oxygen in bearing steel

Figure 17 Evolution of rolling fatigue life of bearing steel (ball bearing: 6206)

3.2.2 Longer Life by Development of Special Bearing Steels

To restrict cracking extension, bearing manufacturers have developed bearings whose life is six times longer compared to

conventional bearings. Bearing steel structural phase and temper resistance are strengthened by adding Ni and Si in

cooperation with steel manufacturers (Figure 18).

Figure 18 Fatigue life test results of high-strength bearing steel

3.2.3 Longer Life at High Temperature with Special Bearing Steel Development

One of the requirements of the steel mill process is longer life at high temperatures. This is in addition to the already severe

conditions of rolling bearings. By developing special bearing steel with an added alloy component, longer life can be

achieved for up to 250°C. Life is 3.5 times at room temperature and 30 times at 200°C compared to conventional bearing

Bear

ing

life, h

Vacuum degassing

Ladle refining

Continuous casting

> 7 times

�Rated life

Years

Accum

ula

ted

failu

re p

roba

bilit

y, %

● Clean oil lubrication

Test bearings: 6206 ball bearings

Load: 9 kN

Lubricating oil: #68 turbine oil

Calculated life General

bearing

steel

High-

strength

bearing

steel

Life, h

steel (Figure 19).

Figure 19 Life test at 200°C

3.2.4 Longer Life Under Contaminated Lubricating Oil for Special Heat-Treated Bearing Steel

To satisfy longer life requirements of transmission bearings, which are used under severe running conditions, that is, running

under contaminated oil with steel chips, we developed bearings with a life that is 10-times longer compared to conventional

bearings. This was accomplished by applying special heat treatment to obtain the optimum retained austenite and to form an

improved hard surface (Figure 20).

Figure 20 Fatigue life test of tapered roller bearings with optimum steel and

heat treatment under contaminated oil

Life (× 105) Life ratio

SUJ2 9.1 1

STJ2 No flaking > 30

Accum

ula

ted

failu

re p

roba

bilit

y, %

Test temperature: 200°C

Test-piece: ø47 × 7 mm plate

Used balls: ø6.35 (1/4”) Si3Ni4 balls

Contact stress: 5.5 GPa

Loading speed (frequency): 3000 times/min

Lubricant: Ether-base oil

103 107105 108

99

5

10

20

80

50

1

Life (load cycle)

SUJ2

STJ2 A

ccum

ula

ted f

ailu

re p

robab

ility

, %

Life (h)

● Contaminated oil lubrication

Specimen: TRA0607RYR

Load: Fa = 13.7 kN

Fr = 20.7 kN

Speed: 2000 rpm

Foreign particles: Total 0.12 wt% (1.1 g/l)

General

bearings

Improved

bearings

3.2.5 Longer Life by Insulated Layer (Film)

Electric corrosion (scales and chips) occurs in bearings for railway traction motors due to the passing of an electric current

through the bearings. Scales and chips decrease bearing life. To prevent passing of the current, an insulated layer

(sputtering of ceramic or PPS injection molding) is provided on the exterior of the outer ring. By applying high insulation

(more than 1000 MΩ), bearing life is extended two to three times longer than conventional bearings (Photos 1 and 2).

Photo 1 Ceramic-insulated bearings

Photo 2 PPS-insulated bearings

3.3 High Speeds

Rolling bearings used to support rolling parts of all industries are constantly being developed to meet the requirements of

high speeds and performance year after year.

Figure 21 shows the history of high speeds for rolling bearings of machine tool main spindles. Figure 22 shows the present

conditions of high-speed bearings by industry.

.

Figure 21 History of rolling bearing speeds for machine tool main spindles

d·n value: Bearing bore diameter, d (mm) × speed, n (rpm)

d·n

val

ue×

10

6

85 90 95 2000 1965 70 75 80

0.5

1.0

1.5

2.0

2.5

0

Lathes and milling

machines

Tapered roller bearings

(Forced lubricating

oil circulation)

Machining centers, NC lathes

and milling machines

High-speed machining centers

High-speed angular

contact ball bearings

Ceramic ball bearings

(Oil-air lubrication) High-speed machining centers

Ball bearings with ceramic balls

(Grease lubrication)

Ultra high-speed or high rigidity machining centers

Angular contact ball bearings

Cylindrical roller bearings

(Jet lubrication)

Years

Angular contact ball bearings

Cylindrical roller bearings

(Grease lubrication)

To achieve

(lubrication,

ceramic bal

Besides the

also improv

conservatio

The tenden

high-speed

4. Recycling

Refuse of b

which are a

(Photos 3 a

Aircra

ft

Mac

hin

e t

ools

C

ars

Ele

ctr

ic

appl

iances

Speed

d·n value (× 106)

T

C

Application

Figure 22 The present co

such high speed running of rolling

cooling, etc.) play important roles

ls, and low dynamic loss minute lu

contribution to industrial product

ed to meet requirements of high s

n.

cy of high speed requirements will

technology.

of Bearing Components

earing materials at the press proc

bout 100 thousand tons per year in

nd 4).

Oil-

Jet engines

Internal

grinders

urbochargers

leaner motors

Jet

nditions

bearings

. Beari

brication

ion activ

peed. Th

increase

ess is rep

Japan,

air

Mist

of hi

, opt

ng pr

(oil-

ities

is ha

stea

roc

are r

1 3

Grease

Lubrication method

gh-speed bearings by industry

imum design of rolling bearings a

eload switching technology, low-

air lubrication) are the key point

, bearings used in transportation

s helped reduce costs and has c

dily and we are enthusiastically p

essed as steel scrap. Machining c

emoved from water and oil and re

Present Near future

Machining

centers

Magnetic

clutches

2

nd rela

heat ge

s for at

and info

ontribu

romotin

hips an

cycled

4

Bearing bore

ted technologies

neration interior design,

taining high speeds.

rmation equipment have

ted to energy

g the development such

d burrs from processing,

as raw material for steel

Photo 3 Billets of grinding chips

Photo 4 Billeting machine of grinding chips

In addition to the above, recycling systems for plastic materials have been established. We continue to make efforts to

reduce or reuse the exhaust or used oils at the production process.

Rolling bearings are made of steel. The bearings in cars and home electric appliances, which are major application items,

are reclaimed and recycled as an iron resource.

The Japan Bearing Association increased recycling by 75%, 10 years ahead of schedule. We are now working on targeting

new activities and establishing new goals.

5. Improvement of Noise Characteristics

5.1 Air conditioners

Applications which require low noise are home electric appliances, information equipment, audio-visual equipment, etc.

Fan motors in air conditioners or air cleaners, which are used during night or while people are sleeping, must be quiet in

operation. Figure 23 shows the change of noise level of air conditioners and Figure 24 shows the change of sound level of

bearings for air conditioner fan motors. Clearly, advancements made in ball bearing noise has lead to quieter air conditioners.

40

50

60

Exterior equipment

B

Figure 23 Evolution of air conditioner noise levels

0

20

40

60

80

100

1980 1985 1990 1995 2000

Years

Vib

ration*1　

%

*1 Vibration: Anderon value

Ball bearings (100 at 1980)

Figure 24 Evolution of fan motor bearing sound levels

5.2 Traction Drives

Figure 25 shows a traction drive reducer system which utilizes rolling traction force with ring and rollers in a conventional

planetary gear device.

Figure 25 Traction drive reducer system

Sun roller Planetary rollers

Ring

Ａ

Ａ

Low

spe

ed

side

Hig

h s

peed

side

Ａ－Ａ

By replacing gears with rolling contact, noise and vibration are reduced compared to a conventional power transfer system

as shown in Figure 26.

0

5

10

15

20

0 1000 2000 3000 4000 5000

Sun roller speed, rpm

Vib

ration m

/s2

Traction drive

Planetary gears

Figure 26 Comparison of vibration

5.3 CT Scanners

A CT scanner (Photo 5), which is one of many valuable medical devices, consists of a patient bench and inspection unit. As

shown in Figure 27, the cathode-ray tube and detector (imagery system), are attached to a rotating frame of the inspection

unit. A bearing of 1 m in diameter supports the rotating frame. Though the mechanism is encapsulated, the bearing must still

operate quietly. Bearing speed is increasing to shorten the inspection time and to improve image accuracy. This helps to

reduce stress and burden of the patient.

Photo 5 CT scanner

Cathode-ray tube

Rotating frame

Bearing

Patient bench

Fixed frame

Drive beltDetector

Figure 27 Structure of CT scanner

In medium and low speed models (rotating speed: 40 ~ 90 rpm), a 4-point contact ball bearing (Figure 28) is usually used. To

obtain low noise operation, a resin cage is used in the bearing and internal clearance is settled so that the balls at the

unloaded zone generate little or no noise.

In medium- and high-speed models (rotating speed: 80 ~ 120 rpm), a back-to-back arrangement of angular contact ball

bearings with resin cages (Figure 29), or preloaded double-row angular contact ball bearings (Figure 30), are used to restrict

noise by increasing bearing rigidity. Moreover, the double-row angular contact ball bearings, which are integrated with

surrounding part, enable low noise running with high accuracy.

Figure 28 4-point contact ball bearing

Figure 29 Back-to-back angular contact ball bearings

Figure 30 Integrated double-row angular contact ball bearings

6. Reduction of Materials Inflicting an Environmental Burden

Chemical materials, which are dissolved from product waste and garbage, such as mercury, lead, cadmium, arsenic,

sexivalent chrome, etc, cause an environmental burden.

Rolling bearings, whose major component materials is steel, contain little such materials. Used bearings are usually

recycled together with installed machines, thus, bearings have little effect on environment.

However, some bearing lubricants place a burden on the environment. Usage is very little, as is the case with lead-based,

extreme pressure additives that are contained in lubricating greases. Regardless, we are now replacing such greases with

non-lead type greases to reduce any additional burden on the environment.

In addition, we will continue to develop and make modification to our grease. We have developed and marketed

environmentally conscientious greases that have excellent decomposition characteristics. This is accomplished utilizing the

bacteria that occur naturally in the water and soil of fields, rivers, lakes, and oceans. We have developed greases with safety

in mind and. Results of living organism impact tests of our greases confirm that we achieved a mark of less than one-tenth

of the new eco-mark criteria set for fish (Figures 31 and 32).

Figure 31 Natural decomposition of greases

Figure 32 Impact on ecology

Special fron and 1.1.1-trichroloethane have been used at bearing production lines for cleaning purposes. They are being

replaced or eliminated by new environmentally friendly cleaning methods or equipment, such as a pure water cleaning device

(Photo 6), and a cleaning device using hydrocarbon-base agent, etc.

Natural decomposition

Natural decomposition capability is very high and environmental-friendly (natural decomposition rate: 97.3%)

Nat

ura

l de

com

posi

tion r

ate %

Natural decomposition grease Lithium-mineral oil grease (general grease)

Low impact on ecology system

Acute poisonous test using killifish

LC50 value after 96 hours: more than 1000 mg/l

(New criteria for eco-mark: 100 mg/l)

LC50: 50%-fatal dose density of test on live organism

Judging criteria of poison against ecology

Relative poisonous level LC50 value (mg/l)

Relatively nonpoisonous > 1000

Actually nonpoisonous 100 ~ 1000

Slightly poisonous 10 ~ 100

Poisonous 1 ~ 10

Very poisonous < 1.0

Photo 6 Pure water cleaning system

Although rolling bearings contain few materials that create an environmental burden, we steadily make efforts to reduce

further environmental impact in areas that are not so readily visible.

7. Futures

Taking this all into consideration, we believe you can understand the great contribution to the Earth's environment of rolling

bearings that are used in all rotating equipment and devices.

In the 21st century, laws to prevent further global warming will be rapidly expanded to not only affect home appliances, but

also all other industries including those related to transportation and IT. Therefore, the ultrahigh rigidity or ultra long life of

rolling bearings should be achieved under the development of zero-impurity next-generation bearing materials. Ultra-low

torque bearings with optimum geometric design and extremely low viscosity greases should be also studied.

Together with the promotion of a recycling-oriented society, separable rolling bearings with easily classified reclaiming of

components will become major bearings and the synthetic rubber for seals will be replaced with paper. Grease base oils will

be replaced with animal fat or vegetable oil and environmental contaminated materials will be eliminated from all products. It

is not a dream that all the components will be reused or recycled.

At the rolling bearing production process, wet cutting or grinding using oil or water-based coolants will be changed to dry

cutting or grinding, free of oil mist. This will create a comfortable working environment and zero garbage at the production

process, thus achievement of zero emissions is feasible.

With bearing industry action plans, together with member companies considering the above conditions, the Japan Bearing

Association, Global environment committee is aggressively promoting energy conservation and garbage reduction. We will

study to make environmentally friendly products a long-term goal utilizing the lifecycle assessment (LCA) analysis.

<Reference>

Document 1: N. Miyamura, S. Nagano, K. Asano, I. Tanaka,

“Development of needle roller type rocker arms”(Japanese language), Internal Combustion Engines, 26 (1987)