Transcript TAIHO - MYTRIBOS

1
MITC2013
2013．Nov．19
Recent Development of Plain Bearings
for Combustion Engines
Taiho Kogyo Co., Ltd.
TTRF
Yoshio KUMADA
TAIHO
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Contents
1 What is “Plain Bearing for Internal Combustion Engine”?
1.1 Short History
1.2 Needs & Direction of Development
2 Higher Performance, Lead Free
2.1 Al-Sn-Si(-Pb) Alloy Bearing
2.2 Microgrooved Bearing
2.3 Lead Free Overlay
3 Lower Fuel Consumption for Future
3.1 Bearing with Eccentric Oil Groove
3.2 Bearing with Surface Texture
3.3 Friction loss reduced by Fullerene/Graphene coating
4 Conclusion
TAIHO
1 Plain Bearings for Internal Combustion Engine
Camshaft bearing
Con-Rod small-end bearing
Con-Rod big-end bearing
Crankshaft bearing
Small-end
Con-Rod
Big-end
Con-Rod big-end
bearing
Crankshaft
TAIHO
Crankshaft bearing
3
4
1.1 Short History
Scientific Research – Modern age
1687
I. Newton
“Principia”
Newtonian fluid, viscosity law
1883
B. Tower
1886
O. Reynolds
1902
R. Stribeck
experimental work
- discovery of oil film pressure
theoretical work
- Reynolds’ equation
Stribeck curve
1904
A. J. W. Sommerfeld analytic solution of
Reynolds’ equation
A. G. M. Michell tilting pad bearing (patent)
A. Kingsbury
1904
1910
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5
Modern age – White Metal
1839
～
1908
J.Babbitt invention of White metal (1839, USA Patent)
Babbitt metal (Sn-9Sb-2Cu)
T-type Ford, from 1908
White Metal
・Tin base (Sn-Sb-Cu-Pb)
Lead base (Pb-Sb-Cu-Sn)
Soft, Low melting point
Good : conformability, Anti-seizure
Poor : heat resistance, Anti-Fatigue
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Modern age – Copper-Lead, Overlay
1920s
Higher Load Carrying Capacity & Fatigue Resistance
Soft lead phase dispersed in hard metallic matrix
⇒ Basic concept of recent bearing materials
thick-walled cast Cu alloy with 20-50%Pb
afterward,
centrifugal casting or direct casting on back-steel
1939
Powder metallurgy : continuous sintering on back-steel
Around Widely Expanded
1940
– quality, productivity, economic efficiency
afterward, Cu-Pb with Overlay (electroplated, 20μm)
Higher conformability & Anti-seizure
around Pb-Sn-Cu, Pb-Sn, Pb-Sn-In, Pb-In
1970 Ni intermediate layer
TAIHO
20μm
7
Modern age – Aluminum Alloy
World War I Lack of Heavy Metals
1920s
1930s
1950s
1970s
Rolls-Royce(GB) thick-walled cast duralumin with
Overlay, C/R, P/P
USA Al-6Sn with Sn Overlay
VW(DE) Al-5Zn-SiCuPbMg
USA Bimetal
GB Al-20Sn without Overlay
USA, JPN Al-Pb Casting, Powder sintering
Al-20Sn
TAIHO
As Cast
Bimetal
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Structure of Engine Bearing and Cross-Sectional View
Bearing alloy
(Lining)
Overlay
Ni barrier
20μm
Back Steel
Al-12Sn-2.7Si-1Cu(-2Pb)
Bearing lining
Pb-6In-7Sn/Cu-23Pb
Bearing lining
back steel
back steel
Al alloy bearing
TAIHO
20μm
Cu-Pb alloy bearing
with overlay
Cu-Pb alloy
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1.2 Needs and Direction of Development
1.2.1 Bearing Pattern
Prof. Norimune Soda said, “There is an effective method of using
bearings, which is called the bearing law, that is the Bearing pattern”.
軸受には軸受法という法則があり，当たりこそ軸受法である．（曽田先生）
Severity of engine bearings
Maximum unit load : Pmax = 50 -100 MPa
Minimum oil film thickness :
hmin = 0.4 - 0.8 μm
＃1
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＃2
＃3
＃4
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1.2.2 Conformability, Running-in
Development of Bearings・・・the challenging theme how to make
running-in of the bearing materials with higher strength
Pb Free
１ Thin Overlay
Pb base Overlay
２ Hard Particle in the Lining
2.1 Al-Sn-Si Alloy
３ Softer Middle Layer
Al-Sn-Si Alloy + Underlay
４ Micro Regular Shape
in the Surface
2.2 Microgrooved Bearing
TAIHO
2.3 Pb free Overlay
Ref. : Y. Kumada, Journal of Japanese Society of Tribologist，41, 1 (1996) 28
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1.2.3 Trends of Engines & Influences on Bearing
Trend of Engines
Influences on Bearing
→
Solution
High performance
・Higher Unit Load
2.1 Al-Sn-Si alloy,
2.2 Microgrooved Bearing
(2.3 Lead Free Materials)
Improve of
Fuel Consumption
・Lower Rigidity of Housing
・Narrow Width → Higher Unit Load
・Lower Viscosity Oils
・Excessive wear
(2.2 Microgrooved Bearing)
(2.3 Lead Free Overlay)
3.1 Eccentric grooved Bearing
3.2 Surface texture
Clean Exhaust Gas
・Higher Oil Temp.
・Higher Unit Load
Reduction of
Noise & Vibration
・Smaller Diametral Clearance
Reduction of
Environmental
Substances of
Concerns
Others
longer life, cost reduction
TAIHO
2.2 Microgrooved Bearing
2.3 Lead Free Materials
・Higher Durability
・Lower cost
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2.1 Al-Sn-Si Alloy Bearing
2.1.1 Seizure by Nodular Cast Iron Shaft
TAIHO
Ref. : T. Fukuoka, H. Kato, S. Kamiya, N. Soda, SAE Technical Paper, 830308 (1983)
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2.1.2 Lapping shaft surface by hard particles, Si
Fig. seizure process of Al-alloy bearings and new concept
Fig. seizure property of two kinds of Al-alloy bearings
TAIHO
Ref. : T. Fukuoka, H. Kato, S. Kamiya, N. Soda, SAE Technical Paper, 830308 (1983)
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2.1.3 larger Si particle Size（2→5μm）
20μm
normal
80
60
40
20
0
20μm
Larger Si
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Wear amount ，mm
100
Al-12Sn-2.8Si
1
2
3
4
Si Mean particle size, mm
5
GO-STOP 50kcycles
2.2MPa
120C ATF
SCM420H
carburizing & quench
Ref. : T．Desaki et al., JSAE Review, 21, 3 (2000) 321.
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2.2 Microgrooved Bearing （MGB)
0.1～0.4 mm
3～6 μm
３
TAIHO
Ref. : Y. Kumada, Dissertation in The University
of Tokyo （1996）
2.2.1 Al alloy bearings (after engine endurance test)
Look at the bearing pattern！
Normal Plain Bearing
Microgrooved Bearing
Engine: V6,3.0L
6,300r/min×WOT
×100h
Block side
Bearing:Crankshaft
bearing
Al-Sn-Si alloy
Cap side
＃1
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＃2
＃3
＃4
16
＃1
＃2
＃3
＃4
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Bearing backside temp.,℃
2.2.2 Bearing temperature rise
MGB G24
MGB G23
NPB
180
NPB
Lead Bronze with Overlay
Seizure
160
Al-Sn-Si alloy NPB
Test condition
Al-Sn-Si alloy MGB G24
140
5000
6000
7000
Engine：I-6, 2000cc, gasoline
#4 crankshaft bearing was measured
Load：W.O.T.
Lubricant：7.5W-30 SE
Oil temperature：130℃
8000
Rotational speed, r/min
ΔT＝kQ/G
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Oil flow
Heat generation
Ref.：Y. Kumada et al., Tribology Trans., 39, 1 (1996) 81
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Prof. Kimura says,
It is common that a plain bearing has
plane surface in order to carry the
load by oil film pressure.
An engineer of Taiho Kogyo in which
I have taught Tribology for forty
years, proposed the idea in a
confident attitude. “The idea, which
Surface has many grooves, is not
common. That is very interesting.”
■Contribution to improving fuel
consumption, lower cost et al.
●Received the first JAST award
(1996. 5)
2004.2.24 Asahi Newspaper
Main stream of Engine Bearings
（around 75% of worldwide Taiho engine bearings）
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2.3 Lead Free Materials
2.3.1 Lead Amount of Typical Plain Bearings
Category
Composition
White Metal
Sn base
Pb base
Overlay
Pb base
Sn base
Al alloy
Al-Sn
Al-Sn-Si-Pb
Al-Pb-Si
Al-Zn-Si-Pb
Al-Cd
Cu alloy
Cu-Pb-Sn
Cu-Sn
Cu-Graphite
TAIHO Ref.：S. Kamiya, Document of 47
Pb amount in a piece of bearing
1
2
3
4
5
6
7
(mass%)
8
9
Overlay
Lining
th
Back steel
Contingence-Composite session meeting, JSTP (2001)
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2.3.2 Pb Free Bearing Materials
Taiho Kogyo
Aluminum
Alloy
other companies
Al-20Sn-1Cu
Al-(12-15)Sn-3Si-1Cu-Cr,Zr,V,Mn
Al-(6-7)Sn-3Si-(1-1.5)Cu-Cr,Zr,V,Mn
Al-(4-5)Zn-Si-Cu
Overlay
PAI-72MoS2 (Solid
Lubricant Overlay)
PAI-(18-20)MoS2-(10-18)Gr,WS2
PTFE-MoS2-Gr
Copper
Alloy
Cu-4Sn-7Bi
Cu-6Sn-Ag
Cu-(4-10)Sn-(4-8)Bi-Mo2C,Zn,Ni
Cu-(5-8)Sn-Ni,P
Cu-20Zn-Ni,Al,Mn,Fe
Overlay
PAI-72MoS2 (S.L.O)
Bi
Sn
Sputter (Al–20Sn)
Bi/Ag, Bi
Sn-(2-8)Cu
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2.3.3 Solid Lubricant Overlay
PAI+MoS2
Overlay
Cross-section of Overlay
Good conformability for initial running-in
Low friction by solid lubricant, MoS2
PAI(thermosetting resin) for binder
+
MoS2 (solid lubricant) 40vol%
Thickness 6μm
TAIHO
“Pb free bearings”
JSME “Technology Award” in 2003
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Fatigue resistance of Al-Sn-Si alloy bearing
with solid lubricant overlay
better
Al-7Sn-2.7Si-1.5Cu-Cr-Zr/ PAI-72MoS2
TAIHO
Ref.：Y. Kumada et al., VDI-Berichte Nr. 1906 （2006）113
23/５８
23
Touareg
Adopted for VW W12
crankshaft bearings
TAIHO
Ref. : R.Szengel, F.T.Metzner & M.Dehmke,
Aachener Kolloquium. “Fahrzeug und Motorentechnik”
(2003)
24
Taiho Kogyo developed Crankshaft bearings having
super low frictional property for Mini-vehicle
-- Bearings with solid lubricant overlay --
Ref. : Nikkei Monodukuri，8 (2012) 92.
TAIHO
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2.3.4 Al-Sn Sputter
•Al-Sn sputter (GB, DE, Austria)
Higher Load Carrying Capacity
Slightly Lower Conformability
High production Cost (PVD)
sputtered
Al-20Sn
overlay
Cu-Sn alloy
Sputter (SEM Image)
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3.1 Eccentric oil-grooved bearing for low
fuel assumption
Conventional
Eccentric
Oil flow
in oil groove
TAIHO
Ref. : Y. Hikita et al., ITC KOBE 2005, Book of Synopses (2005) 24.
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3.1.1 Background
Ratio of friction loss
Accessory
Water pump
Piston & Con-rod
Oil pump
16%
Valve train
TAIHO
Crankshaft
28
Connecting rod bearing
Upper
Lower
Crank pin
journal
Engine : L4 1.5L
Oil temperature : 100ºC
Crankshaft
bearing (Upper)
Oil flow , L/min
20
Crush
relief
10
Crank main journal
0
TAIHO
2000
4000
Rotational speed , rpm
6000
Crankshaft
bearing (Lower)
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3.1.2 Eccentric oil-grooved bearing
Conventional
Eccentric
Oil flow
in oil groove
Side flow is
large
reduced
Crush relief area
(Clearance is large)
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3.1.3 Relationship of oil groove end and friction torque
Center
1.2
Depth , mm
0º
q
0.8
0.6
0.4
0.2
90º
0
0
30
Friction torque difference , Nm
0.1
0
No. 1
-0.1
No. 2
No. 3
-0.2
2
4
6
8
Oil flow , L/min
60
θ,º
(Center)
Oil groove end
TAIHO
Conventional
1
10
90
(Parting end)
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4 Conclusion & Future Issues
1 Al-Sn-Si alloy, Microgrooved Bearings were adopted in
almost all automotive engines, and have become
standard ones.
2 Regarding Lead free bearings, we have to develop high
performance engine bearings, that is, the bearings
satisfying both of running-in property and material
hardness.
3 It is desired that mechanical loss caused by bearing
friction will be near zero, so near zero friction bearings
have to be developed near future.
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150
150
100
100
50
6
重量
PS
50
0
1960
70
年代 ｴﾝｼﾞﾝ型式 出力
1960
Ｒ型
1970 Ｔ－Ｕ型
1980
1990
TAIHO
６０PS
78PS
５Ａ
８５PS
６０００
ＲＰＭ
５Ｅ
１０５PS
６４００
ＲＰＭ
80
90
重量 適用車種
2000
軸受負荷PS/cm2
200
出力PS
重量ｋｇ
表４　同一排気量（１５００ｃｃ）エンジンの年代毎の軸受負荷容量の変化
PS/cm2
4
2
0
1960
年度
軸受寸法
軸受材質
Ｍ／Ｎ（１）:Φ６１．６×３０×１．７９
Ｍ／Ｎ（２）:Φ６１．６×３４×１．７９
M/N,C/R,C/M
Ｍ／Ｎ（３）:Φ６１．６×４０×１．７９
ホワイトメタル
Ｃ／Ｒ：Φ５３×２７×１．５０
負荷容量１5MPa
Ｐ＝６０/4×５×２．６
＝１．１５ＰＳ/ｃｍ2
70
80
内部構成部品
90
2000 年度
備考
４気筒３点支持
鍛造軸
カム軸歯車駆動
スラスト軸受は
リア側で支持
１６６Ｋｇ
コロナ
141Ｋｇ
セリカ
カローラ
カリーナ
Ｍ／Ｎ:Φ６２×２０．８×２．０
Ｃ／Ｒ：Φ５１×１９×１．５
Ｐ＝７８/４×４．８×１．８
＝２．２６ＰＳ/ｃｍ2
Ｍ／Ｎ，Ｃ／Ｒ
Ｐｂ-Ｓｎ-Ｃｕ付
銅・鉛合金
負荷容量３０MPa
Ｃ／Ｍ
ホワイトメタル
４気筒５点支持
ＤＣＩ軸
カム軸チエン駆動
スラスト軸受は
センターで支持
１１６Ｋｇ
カリーナ
カローラ
コロナ
Ｍ／Ｎ：Φ５２×２０×２．０
Ｃ／Ｒ：Φ４３×１７．１×１．５
Ｐ＝８５/４×４×１．７４
＝３．０５ＰＳ/ｃｍ2
Ｍ／Ｎ，Ｃ／Ｒ
ＡＬ-Ｓｎ-Ｓｉ
負荷容量３０MPa
４気筒５点支持
ＦＣＤ７０軸
ＤＯＨＣ軸
タイミングベルト駆動
スラスト軸受は
センターで支持
Ｍ／Ｎ，Ｃ／Ｒ
ＡＬ-Ｓｎ-Ｓｉ
負荷容量３5MPa
４気筒５点支持
ＦＣＤ軸
ＤＯＨＣ軸
タイミングベルト駆動
スラスト軸受は
センターで支持
１０７Ｋｇ
Ｍ／Ｎ：Φ５４×１６×２．０
ターセル
Ｃ/Ｒ：Φ４６×１６×１．５
カローラⅡ
Ｐ＝１０５/4×４．３×１．４
コルサ
＝４．３６ＰＳ／ｃｍ2
by K. Niwa
35
Trends of Automotive Engines & Influences on Bearing
Needs
No.
1
High performance
Trend of Engines
Influences on Bearing
・Direct ignition & higher cylinder ・Higher Unit Load
pressure (Gasoline)
→①Al-Sn-Si alloy,
・High pressure fuel jet & higher
②Microgrooved Bearing
cylinder pressure (Diesel)
・Down-size, Thin wall, Light
・Lower Rigidity of Housing
weight Materials (Al alloy)
・Reduction of Friction Loss
・Narrow Width → Higher Unit Load
・Increase of Start–Stop Operation ・Lower Viscosity Oils
・Excessive Wear
・Lower volume of Oil Pump
④Eccentric grooved Bearing
・EGR
・Higher Oil Temp.
・Direct ignition & higher cylinder ・Higher Unit Load
pressure
・Smaller Diametral Clearance
・Reduction of bearing slap noise ②Microgrooved Bearing
2
Improve of
Fuel Consumption
3
Clean Exhaust Gas
4
Reduction of
Noise & Vibration
5
Reduction of
・Less or Free of lead
Environmental
Substances of Concerns
・③Lead Free Materials
6
Others
・Higher Reliability
longer life, cost reduction ・Commoditizing
・Higher Durability
・Commoditizing, Lower cost
TAIHO
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４ 今後の課題と方向
No.
Needs
Trend of Engines
Influence on Bearings
年頃
High performance
・Direct ignition & higher
・ higher unit load
cylinder pressure (Gasoline)
1970年～
・High pressure fuel jet & higher →鉛青銅系ライニング、
2000年
鉛系オーバレイ
cylinder pressure (Diesel)
・ マイクログルーブ軸受（MGB）
Improve of
Fuel Consumption
・Down-size, Thin wall, Light
・Lower Rigidity of Housing
weight Materials (Al alloy)
・Reduction of Friction Loss
・Narrow Width → Higher Unit Load
・Increase of Start–Stop Operation・Lower Viscosity Oils
1995年～
・Excessive Wear
・Lower volume of oil pump
現在
3
Clean Exhaust Gas
・EGR
・Direct ignition & higher
cylinder pressure
・Higher Oil Temp.
・Higher Unit Load
4
Reduction of
Noise & Vibration
・Reduction of bearing slap
noise
・Smaller Diametral Clearance
1990年～
2000年
5
Reduction of Environmental
Substances of Concerns ・Less or Free of lead
・Lead Free Materials
1995年～
現在
6
Others -- longer life,
cost reduction
1
2
TAIHO
・Higher Reliability
・Commoditizing
・Higher Durability, Commoditizing,
Lower cost
1975年～
2005年
37
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3.3 鉛フリー軸受
3.3.1 従来（Pb含有）軸受の性能位置付け
コンロッド軸受最高出力時
120
最大軸受面圧 ，MPa
今後の開発エンジンの領域（予測）
100
80
【材料記号説明】
オーバレイ材／ライニング材
ディーゼル
エンジン
60
40
一般ガソリン
エンジン
20
8
TAIHO
Pb基ｵｰﾊﾞﾚｲ
付き銅鉛合金
or 鉛青銅
スポーツタイプ
ガソリンエンジン
12
16
周速 ，m/s
Al-Sn-Si-Pb合金
20
24
Concept of Pb Free Bearing
Boundary Lubricity
・Addition of Solid lubricants
Graphite(Gr)
MoS2, WS2
PTFE
Sulfide：Cu2S，AgS・・・
Conformability
・Lower hardness
addition of Soft components
Gr，MoS2，PTFE・・
・Addition of Low Melting Point Metal
Bi，Sn，In
・Surface Modification
Sn electroplating
①Solid Lubricant Coating〔 RA500 〕
② Microgrooved Bearing
・Addition of Ag 〔 HS100，HS210〕
・Hard Particle
Enlarged Si，Fe-P，AlN・・・
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39
Coefficient
of friction
③-1 トライボケミカル反応の利用-Agの添加
0.6
0.4
0.2
0
40
Sn-Ag bulk
Cu-5Sn bulk
0.1m Sn-Ag on Cu-5Sn
Sliding distance (time) →
30mm（91sec)
Fig.3 Smaller and stable friction coefficient of Sn-Ag
thinthin
layer
5Sn-1Ag
layer
摺動メカニズム： 油中のS,Oの存在と摩擦熱とによって、極表面に約0.1～0.2μm
の厚さで次の物質が形成される．
(ESCA，AES，EPMA分析結果)
Snリッチ
オイル中の Ag Sn-Sn共晶
3
応力や S，O
（AgS,SnS等）
摩擦熱
部分的に数μm厚さ
のCu2O ,CuSO4
表面
CuSO4
Cu2O，SnO2
の薄い層
表面へのSn,Agの富化
TAIHO
Ag
Sn
Cu
Sn,Agを固溶した
非平衡Cuマトリックス
軸
受
合
金
出典：神谷荘司，名古屋大学学位論文
（1999）
41
TAIHO
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【試験方法】
試験機 ： 高面圧軸受試験機
軸受材質 ： SA162, RA530/SA250
軸受寸法 ： 内径φ42×幅17mm
給油温度 ： 140℃
試験軸 ： S55C 焼入れ
表面粗さRzJIS 0.5μm
硬さ 500 - 600HV10
試験機
荷重パターン
モーター
供試軸受
オイルバス
回転数
[r/min]
1300
油圧ピストン
0
軸受面圧
[MPa]
ひずみゲージ
軸
TAIHO
45
45
135
90
175
135
220 〔min〕
40
30
20
10
5
0
90
50
45min毎に
10MPaステップアップ
175
220 〔min〕
混合潤滑領域の摩擦係数，焼付き面圧を確認
43
1.1 Short History
Industry Revolution
1750
～
Half bearing (←Leonardo da Vinci at the Renaissance)
:replaceable in case of excessive wear
1850
Bearing Materials
: cast iron,
bronze, brass,
pewter (Alloy of tin, lead and zinc)
Brass half bearing
Ref. : D．Dowson, History of Tribology 2nd edition, Professional Engineering Pub. (1998) 201.
TAIHO
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2.3.5 Sn,Bi electroplating
Cross
-section
Overlay
surface
Overlay
Crystal size Hardness
fracture s.
BP100X
Sn
/Cu-6Sn-1Ag
12HV
基材
Size：１-５μm
Granule
PK1
Bi/Ag
/Cu-10Sn-4Bi-Mo2C
Bi:5μm
Ag
5μm
Size：-１μm
TAIHO
22HV
Ag:5μm
CX4
裏金
Bi
基材
5μm
Dendrite
5μm
基材
Fine
45
3.1.4 temperature increase and embeddability
of Eccentric oil-grooved bearing
A : Crank pin lower side
B : Crankshaft bearing back side
1
+1.5ºC
+0.8ºC
145
+1.4ºC
0.8
140
135
+2.1ºC
+1.2ºC
+2.5ºC
130
Eccentric
[ Test conditions ]
Engine : L4, 1.5L
Rotational Speed : 6400rpm
Oil Temp. : 120ºC
TAIHO
No. 3
No. 2
No. 1
Conventional
125
Embedded Rate
Temperature , ºC
150
0.6
0.4
0.2
0
Conventional
No.1
No.2
Embedded rate of foreign particles
on connecting rod bearings