taiho 1 recent development of plain bearings for combustion engines 2013 . nov . 19 taiho kogyo...
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Recent Development of Plain Bearings for Combustion Engines
2013 . Nov . 19
Taiho Kogyo Co., Ltd.TTRF Yoshio KUMADA
MITC2013
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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
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1 Plain Bearings for Internal Combustion Engine
Camshaft bearing
Con-Rod small-end bearing
Con-Rod big-end bearing
Crankshaft bearing
Crankshaft bearing
Con-Rod big-end bearing
Crankshaft
Con-RodSmall-end
Big-end
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Scientific Research – Modern age Scientific Research – Modern age
1687 I. Newton “Principia” Newtonian fluid, viscosity law 1883 B. Tower experimental work
- discovery of oil film pressure1886 O. Reynolds theoretical work - Reynolds’ equation1902 R. Stribeck Stribeck curve
1904 A. J. W. Sommerfeld analytic solution of Reynolds’
equation1904 A. G. M. Michell tilting pad bearing (patent)
1910 A. Kingsbury
1.1 Short History
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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-
seizurePoor : heat resistance, Anti-
Fatigue
Modern age – Modern age – White MetalWhite Metal
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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-steel1939 Powder metallurgy : continuous sintering on back-steelAround Widely Expanded 1940 – quality, productivity, economic efficiency afterward, Cu-Pb with Overlay (electroplated, 20μm)
Copper-Lead, OverlayCopper-Lead, OverlayModern age – Modern age –
Higher conformability & Anti-seizurearound Pb-Sn-Cu, Pb-Sn, Pb-Sn-In, Pb-In 1970 Ni intermediate layer
20μm
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World War I Lack of Heavy Metals
1920s Rolls-Royce(GB) thick-walled cast duralumin with
Overlay, C/R, P/P1930s USA Al-6Sn with Sn Overlay VW(DE) Al-5Zn-SiCuPbMg1950s USA Bimetal GB Al-20Sn without Overlay
1970s USA, JPN Al-Pb Casting, Powder sintering
Aluminum AlloyAluminum AlloyModern age – Modern age –
Al-20Sn
As Cast Bimetal
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Pb-6In-7Sn/Cu-23PbBack Steel
Bearing alloy(Lining)
Cu-Pb alloy bearingwith overlay
Al-12Sn-2.7Si-1Cu(-2Pb)
20μm
OverlayNi barrier
Cu-Pb alloy
Structure of Engine Bearing and Cross-Sectional View
20μm
back steel
Al alloy bearing
back steel
Bearing lining Bearing lining
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1.2 Needs and Direction of Development1.2.1 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)
# 1 # 2 # 3 # 4
Severity of engine bearings
Maximum unit load : Pmax = 50 -100 MPa
Minimum oil film thickness : hmin = 0.4 - 0.8 μm
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Ref. : Y. Kumada, Journal of Japanese Society of Tribologist , 41, 1 (1996) 28
1.2.2 Conformability, Running-inDevelopment of Bearings ・・・ the challenging theme how to make running-in of the bearing materials with higher strength
1 Thin Overlay
2 Hard Particle in the Lining
3 Softer Middle Layer
4 Micro Regular Shape in the Surface
Pb base Overlay
Pb Free
2.3 Pb free Overlay
2.1 Al-Sn-Si Alloy
2.2 Microgrooved Bearing
Al-Sn-Si Alloy + Underlay
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2.1 Al-Sn-Si alloy, 2.2 Microgrooved Bearing(2.3 Lead Free Materials)
(2.2 Microgrooved Bearing)(2.3 Lead Free Overlay)3.1 Eccentric grooved Bearing3.2 Surface texture
・ Higher Oil Temp.・ Higher Unit Load
2.2 Microgrooved Bearing
・ Higher Durability・ Lower cost
High performance
Improve of Fuel Consumption
Clean Exhaust Gas
Reduction of Noise & Vibration
Otherslonger life, cost reduction
Reduction of Environmental Substances of Concerns
2.3 Lead Free Materials
1.2.3 Trends of Engines & Influences on Bearing
Trend of Engines Influences on Bearing → Solution
・ Higher Unit Load
・ Lower Rigidity of Housing・ Narrow Width → Higher Unit Load・ Lower Viscosity Oils・ Excessive wear
・ Smaller Diametral Clearance
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2.1 Al-Sn-Si Alloy Bearing
2.1.1 Seizure by Nodular Cast Iron Shaft
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
Ref. : T. Fukuoka, H. Kato, S. Kamiya, N. Soda, SAE Technical Paper, 830308 (1983)
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Fig. seizure property of two kinds of Al-alloy bearings
Fig. seizure process of Al-alloy bearings and new concept
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Al-12Sn-2.8Si
normal
Larger Si
GO-STOP 50kcycles2.2MPa120C ATFSCM420H carburizing & quench
0
20
40
60
80
100
1 2 3 4 5
Wear
am
ount
,m
m
Si Mean particle size, mm
2.1.3 larger Si particle Size ( 2→ 5μm )
Ref. : T . Desaki et al., JSAE Review, 21, 3 (2000) 321.
20μm
20μm
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0.1 ~ 0.4 mm
3 ~ 6 μm
3
2.2 Microgrooved Bearing ( MGB)
Ref. : Y. Kumada, Dissertation in The University of Tokyo ( 1996 )
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2.2.1 Al alloy bearings (after engine endurance test) Look at the bearing pattern !
Microgrooved Bearing Normal Plain Bearing
# 1 # 2 # 3 # 4 # 1 # 2 # 3 # 4
Blo
ck sid
eC
ap
side
Engine: V6,3.0L 6,300r/min×WOT ×100h
Bearing:Crankshaft bearing Al-Sn-Si alloy
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2.2.2 Bearing temperature rise
Test condition
Engine : I-6, 2000cc, gasoline#4 crankshaft bearing was measuredLoad : W.O.T.Lubricant : 7.5W-30 SEOil temperature : 130℃
140
160
180
Rotational speed, r/min
Beari
ng
back
sid
e t
em
p.,
℃
5000 6000 7000 8000
MGB G24 MGB G23 NPB
Seizure
Al-Sn-Si alloy NPB
Al-Sn-Si alloy MGB G24
Lead Bronze with Overlay
NPB
ΔT = kQ/G Oil flowHeat generation
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Ref. : Y. Kumada et al., Tribology Trans., 39, 1 (1996) 81
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■Contribution to improving fuel consumption, lower cost et al.
●Received the first JAST award (1996. 5)
Main stream of Engine Bearings( around 75% of worldwide Taiho engine bearings )
It is common that a plain bearing hasplane 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, whichSurface has many grooves, is not common. That is very interesting.”
2004.2.24 Asahi Newspaper
Prof. Kimura says,
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2.3 Lead Free Materials2.3.1 Lead Amount of Typical Plain Bearings
Pb amount in a piece of bearing (mass%)
White Metal
Overlay
Al alloy
Cu alloy
Sn basePb base
Pb baseSn base
Al-SnAl-Sn-Si-PbAl-Pb-SiAl-Zn-Si-PbAl-Cd
Cu-Pb-SnCu-SnCu-Graphite
Category Composition 1 2 3 4 5 6 7 8 9
OverlayLining
Back steel
Ref. : S. Kamiya, Document of 47th Contingence-Composite session meeting, JSTP (2001)
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2.3.2 Pb Free Bearing Materials
Taiho Kogyo other companies
Aluminum Alloy
Overlay
Copper Alloy
Overlay
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
PAI-72MoS2 (Solid PAI-(18-20)MoS2-(10-18)Gr,WS2
Lubricant Overlay) PTFE-MoS2-Gr
Cu-4Sn-7Bi Cu-(4-10)Sn-(4-8)Bi-Mo2C,Zn,NiCu-6Sn-Ag Cu-(5-8)Sn-Ni,P Cu-20Zn-Ni,Al,Mn,Fe
PAI-72MoS2 (S.L.O) Sputter (Al–20Sn)Bi Bi/Ag, BiSn Sn-(2-8)Cu
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2.3.3 Solid Lubricant Overlay PAI+MoS2
Good conformability for initial running-in Low friction by solid lubricant, MoS2 PAI(thermosetting resin) for binder + MoS2 (solid lubricant) 40vol% Thickness 6μm
Good conformability for initial running-in Low friction by solid lubricant, MoS2 PAI(thermosetting resin) for binder + MoS2 (solid lubricant) 40vol% Thickness 6μm
Cross-section of Overlay
Overlay
“Pb free bearings”JSME “Technology Award” in 2003
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Al-7Sn-2.7Si-1.5Cu-Cr-Zr/PAI-72MoS2
better
Fatigue resistance of Al-Sn-Si alloy bearing with solid lubricant overlay
Ref. : Y. Kumada et al., VDI-Berichte Nr. 1906 ( 2006 ) 113
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Touareg
Adopted for VW W12 crankshaft bearings
Ref. : R.Szengel, F.T.Metzner & M.Dehmke, Aachener Kolloquium. “Fahrzeug und Motorentechnik” (2003)
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Ref. : Nikkei Monodukuri , 8 (2012) 92.
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Taiho Kogyo developed Crankshaft bearings having super low frictional property for Mini-vehicle -- Bearings with solid lubricant overlay --
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•Al-Sn sputter (GB, DE, Austria)
Higher Load Carrying Capacity
Slightly Lower Conformability
High production Cost (PVD)sputteredAl-20Snoverlay
Cu-Sn alloySputter (SEM Image)
2.3.4 Al-Sn Sputter
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3.1 Eccentric oil-grooved bearing for low fuel assumption
Conventional Eccentric
Oil flow in oil groove
parti
ng e
nd
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Ref. : Y. Hikita et al., ITC KOBE 2005, Book of Synopses (2005) 24.
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Ratio of friction loss
Piston & Con-rod
Accessory
Valve train Crankshaft
Oil pump 16%
Water pump
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3.1.1 Background
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Engine : L4 1.5LOil temperature : 100ºC
0
10
20
2000 4000 6000Rotational speed , rpm
Oil
flow
, L
/min
Crankshaft bearing
Connecting rod bearing
Valve train
Crankshaftbearing (Upper)
Connecting rod bearing Upper Lower
Crank pinjournal
Crank main journal
Crankshaftbearing (Lower)
Crushrelief
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Conventional Eccentric
Oil flow in oil groove
largeSide flow is
parti
ng e
nd
reduced
Crush relief area(Clearance is large)
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3.1.2 Eccentric oil-grooved bearing
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-0.2
-0.1
0
0.1
2 4 6 8 10Oil flow , L/min
Fric
tion t
orq
ue d
iffere
nce
,
Nm
Conventio
nal
No. 1
No. 2
No. 3
Eccentri
c
q0º
90º
Partin
g
end
Oil groove end
Cen
ter
0
0.2
0.4
0.6
0.8
1
1.2
0 30 60 90 θ , º
Depth
, m
m
Conventional
No. 1
No. 2
No. 3
(Center) (Parting end)
30
3.1.3 Relationship of oil groove end and friction torque
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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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年代 エンシ ン゙型式 出力 重量 適用車種 軸受寸法 軸受材質 内部構成部品 備考
1960 R型 PS60 166Kg コロナ
:Φ × ×M/N(1) 61.6 30 1.79:Φ × ×M/N(2) 61.6 34 1.79:Φ × ×M/N(3) 61.6 40 1.79
Φ × ×C/R: 53 27 1.50/ 4× ×P=60 5 2.6
/=1.15PS cm2
M/ N,C/ R,C/ Mホワイトメタル
5MPa負荷容量1
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
1970 T-U型 78PS 141Kgセリカ
カローラカリーナ
:Φ × ×M/N 62 20.8 2.0Φ × ×C/R: 51 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MPa負荷容量30
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
1980 5APS85
6000RPM
116Kgカリーナカローラコロナ
Φ × ×M/N: 52 20 2.0Φ × ×C/R: 43 17.1 1.5/ × ×P=85 4 4 1.74
/=3.05PS cm2
M/N,C/R- -AL Sn Si
MPa負荷容量30
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
1990 5EPS105
6400RPM
107Kgターセル
Ⅱカローラコルサ
Φ × ×M/N: 54 16 2.0/ Φ × ×C R: 46 16 1.5
/ 4× ×P=105 4.3 1.4 =4.36PS/cm2
M/N,C/R- -AL Sn Si
5MPa負荷容量3
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
50
100
150
200
1960 70 80 90 2000 年度
重量
kg
0
50
100
150
PS出
力
重量PS
0
2
4
6
1960 70 80 90 2000 年度
PS/c
m2
軸受
負荷
PS/ cm2
by K. Niwa
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Trends of Automotive Engines & Influences on Bearing
Needs Trend of Engines Influences on Bearing
・ Direct ignition & higher cylinder pressure (Gasoline)・ High pressure fuel jet & higher cylinder pressure (Diesel)
No.
・ Down-size, Thin wall, Light weight Materials (Al alloy)・ Reduction of Friction Loss・ Increase of Start–Stop Operation
・ Lower volume of Oil Pump・ EGR・ Direct ignition & higher cylinder pressure
・ Reduction of bearing slap noise
・ Higher Reliability・ Commoditizing
・ Higher Unit Load →① Al-Sn-Si alloy, ② Microgrooved Bearing
・ Lower Rigidity of Housing
・ Narrow Width → Higher Unit Load・ Lower Viscosity Oils・ Excessive Wear④Eccentric grooved Bearing・ Higher Oil Temp.・ Higher Unit Load
・ Smaller Diametral Clearance②Microgrooved Bearing
・ Higher Durability・ Commoditizing, Lower cost
1
2
3
4
5
High performance
Improve of Fuel Consumption
Clean Exhaust Gas
Reduction of Noise & Vibration
Others longer life, cost reduction6
Reduction of Environmental Substances of Concerns
・ Less or Free of lead ・③ Lead Free Materials
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4 今後の課題と方向Influence on Bearings 年頃
・ higher unit load →鉛青銅系ライニング、 鉛系オーバレイ
1970 年~ 2000 年
1995 年~ 現在
1975 年~ 2005 年
1995 年~ 現在
1990 年~ 2000 年
・ マイクログルーブ軸受( MGB )
High performance
Improve of Fuel Consumption
Clean Exhaust Gas
Reduction of Noise & Vibration
Reduction of Environmental Substances of Concerns
Others -- longer life, cost reduction
Needs Trend of Engines
1
2
3
4
5
6
・ Direct ignition & higher cylinder pressure (Gasoline)・ High pressure fuel jet & higher cylinder pressure (Diesel)
・ EGR・ Direct ignition & higher cylinder pressure
・ Reduction of bearing slap noise
・ Higher Reliability・ Commoditizing
・ Less or Free of lead
・ Down-size, Thin wall, Light weight Materials (Al alloy)・ Reduction of Friction Loss・ Increase of Start–Stop Operation
・ Lower volume of oil pump
No.
・ Higher Durability, Commoditizing, Lower cost
・ Lower Rigidity of Housing
・ Narrow Width → Higher Unit Load・ Lower Viscosity Oils・ Excessive Wear
・ Higher Oil Temp.・ Higher Unit Load
・ Smaller Diametral Clearance
・ Lead Free Materials
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3.3.1 従来( Pb 含有)軸受の性能位置付け
スポーツタイプガソリンエンジン
ディーゼルエンジン
一般ガソリン エンジン
SA161SA151
LN750/HD150LN760/HD240
LN762
8 12 16
20
40
60
80
20周速 , m/s
100
最大
軸受
面圧
,
MP
a
24
120
今後の開発エンジンの領域(予測)
コンロッド軸受最高出力時
【材料記号説明】 オーバレイ材/ライニング材
3.3 鉛フリー軸受
Al-Sn-Si-Pb 合金
Pb 基オーバレイ付き銅鉛合金or 鉛青銅
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・ Addition of Solid lubricantsGraphite(Gr)MoS2, WS2
PTFE Sulfide : Cu2S , AgS ・・・
・ Addition of Ag 〔 HS100 , HS210 〕
・ Addition of Low Melting Point MetalBi , Sn , In
Conformability
・ Lower hardness addition of Soft components Gr , MoS2 , PTFE ・・
・ Surface Modification Sn electroplating ① Solid Lubricant Coating 〔 RA500 〕 ② Microgrooved Bearing
・ Hard Particle Enlarged Si , Fe-P , AlN ・・・
Boundary Lubricity
Concept of Pb Free BearingConcept of Pb Free Bearing
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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 )
③-1 トライボケミカル反応の利用 -Ag の添加
SnAg
Cu
応力や摩擦熱
オイル中の S , O
表面への Sn,Ag の富化
Sn,Agを固溶した非平衡 Cu マトリックス
Cu2O , SnO2
の薄い層
CuSO4
Sn リッチAg3Sn-Sn共晶
( AgS,SnS等)部分的に数 μm 厚さの Cu2O ,CuSO4
表面
軸受
合金
Fig.3Smaller and stable friction coefficient ofSn-Agthin layer
Coefficient
of friction
00.2
0.4
0.6
Sliding distance (time) →30mm(91sec)
Sn-Agbulk
0.1mSn-Agon Cu-5Sn Cu-5Sn bulk
Fig.3Smaller and stable friction coefficient ofSn-Agthin layer
Coefficient
of friction
00.2
0.4
0.6
00.2
0.4
0.6
Sliding distance (time) →30mm(91sec)
Sn-Agbulk
0.1mSn-Agon Cu-5Sn Cu-5Sn bulk
出典:神谷荘司,名古屋大学学位論文 ( 1999 )
5Sn-1Ag thin layer
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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
回転数[r/min]
軸受面圧 [MPa] 20
105
0 45 90 135 175 220 〔 min 〕
1300
45min 毎に10MPa ステップアップ
3040
50
0 45 90 135 175 220 〔 min 〕
混合潤滑領域の摩擦係数,焼付き面圧を確認
軸
供試軸受オイルバス
油圧ピストン
モーター
ひずみゲージ
荷重パターン試験機
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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)
Industry RevolutionIndustry Revolution
Brass half bearing
Ref. : D . Dowson, History of Tribology 2nd edition, Professional Engineering Pub. (1998) 201.
1.1 Short History
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Sn/Cu-6Sn-1Ag
Bi/Ag/Cu-10Sn-4Bi-Mo2C
Size : - 1 μm
Size :1 - 5 μm
Dendrite
Granule
22HV
12HV
Bi:5μm
Ag:5μm
基材
Cross Overlay Overlay Crystal size Hardness -section surface fracture s.
5μm 5μm5μm
Fine
Bi
Ag
基材
基材
BP100X
CX4
裏金
PK1
2.3.5 Sn,Bi electroplating
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0
0.2
0.4
0.6
0.8
1
Conventional No.1 No.2Em
bedded
Rate
Engine : L4, 1.5LRotational Speed : 6400rpmOil Temp. : 120ºC
[ Test conditions ]
A : Crank pin lower side
B : Crankshaft bearing back side
125
130
135
140
145
150
Conventi
onal
No.
1
No.
2
No.
3
Tem
pera
ture
, º
C +0.8ºC +1.5ºC +1.4ºC
+2.1ºC +2.5ºC+1.2ºC
Eccentric
3.1.4 temperature increase and embeddability of Eccentric oil-grooved bearing
Embedded rate of foreign particleson connecting rod bearings