Rolling Contact Bearings & Fuel Efficiency
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Transcript of Rolling Contact Bearings & Fuel Efficiency
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Raju Chaudhary
ROLLING CONTACT
BEARINGS & FUEL EFFICIENCY
Presentation Overview
• Introduction• Contribution of Bearing to overall vehicle fuel efficiency• Significance• Selection For Fuel Efficient Bearings at Normal Conditions• Suggestion For Fuel Efficient Bearings• Total Friction Torque Calculation Formula • Final Result • References
IntroductionRolling bearings play a significant role in energy conservation.
The significant advantage of rolling contact bearings over a sliding contact bearings that it has a low starting friction.
Due to this low friction offered by the rolling contact bearings, these are called antifriction bearings.
Fuel Efficiency in Global environment
The objective of fuel efficiency is to development of a cleaner, more efficient vehicle strategy, policy package, and adopt best practices on fuel economy improvement so as to reduce the average fuel consumption.
Improves Fuel Economy and National Economy
Protects the Environment
Conserves Resources
Significance
Illustration by examplesContribution of Bearing to overall vehicle fuel efficiency
Energy Conservation by Rolling
Figure 1: Comparison of energy consumption for vehicles with and without rolling bearings.
Contribution of Rolling Contact for Roller Tappets and Rocker Arms
Figure 2: Design of rocker arms
Conventional rocker arm (Sliding type) Rocker arm with needle bearings
Contribution of low Friction Tapered roller Bearings
Tapered roller bearings used in automotive power trains 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 the outer ring race way.
Contribution of Automotive Transmission Rolling Bearings
Needle roller bearings are used in transmission gear shafts .Frictional torque has been reduced by about one-tenth with increased machine and fuel efficiency resulting in greater energy conservation.
Figure 4: Application of rolling bearings in sedan transmission
Selection For Fuel Efficient Bearings at Normal Conditions
Bearing Location: Gearbox ShaftAnalytically Test were Conducted For Three Bearings
Deep Groove Ball Bearings Double Row Angular Contact BearingsTaper Roller BearingsConstant Parameter: Fa=3250N, Fr=4000N, n=1750 RPM, Shaft Orientation- Horizontal, Lubricant Viscosity- (120 – 12 ) mm²/s
This is Suggested By SKF
Further low Friction Tapered roller Bearings can Be Improved Barest Minimal Level
Figure 6: Running torque of low-torque tapered roller bearings
Bearing bore: ø30, ø50 mm Axial load: 3.92 kNLubricant viscosity: 23.3 mm ²/s
Conventional bearings
Improved bearing I
Improved bearing II
Runn
ing
torq
ue
Nm
·
Speed (rpm)
Suggestion For Fuel Efficient Bearingsby Optimized Design
Figure 5:Taper roller bearings
Further Improvement
Turbo Technologies
Improving the Performance of Rolling Element Bearings with Nanocomposite Tribological Coatings.
Experimental and Analytical Methods for Assessing Bearing Performance Under Debris Contaminated Lubrication Conditions.
Total Friction Torque Calculation Formula Applied
Total Friction TorqueM=MM=Mll+M+Mvv+M+Mff
Total Friction Loss (H)=0.001M.Total Friction Loss (H)=0.001M.ωωn: Rotation Speedn: Rotation SpeedMMll : Bearing Friction Torque due to Load : Bearing Friction Torque due to Load
MMvv: Bearing Friction Torque due to Lubrication: Bearing Friction Torque due to Lubrication
MMff:Bearing Friction Torque due to Roller end Flange Load:Bearing Friction Torque due to Roller end Flange Load
Ball Bearings Friction Torque
Torque Due to Applied Load: Ml = flFβdm
Fl=z(Fs/Cs)y
Fβ=0.9Facotα-0.1Fr or Fβ=Fr
For Deep Groove Ball Bearings Having Nominal Contact (Angle 0°)
Fβ=3Fa-0.1Fr
For Thrust Ball Bearings Fβ=Fa
Fs: Static Equivalent Load
Cs: Basic Static Load Rating
Taper Roller Bearings• M=3.35*10-8G(nvo)1/2(ftFr/K)1/3
• M=3.35*10-8G(nvo)1/2Fa1/3
• G=dm1/2D1/6(Z.l)2/3(sinα)-1/3
• Fr/C
r or Fa/Ca≤0.59
• nvo≥2700• G is the Geometry factor based on the internal
dimensions of the bearings.• Z Number of rolling element.
Final Bar Chart
Comparision of Power Losses (W) by SKF and Analytically
Jaipur
Green field project - Gujarat
ManesarNewai
Final Result
Result
Bearing Efficiency also depends upon the Lubrication Type.
From my point of view Taper Roller Bearing is more efficient in compare to power losses at given operating condition.
Analytical Model for calculating and minimizing friction of Roller Bearings
• Catalog Method• Highly specialized Multi Body Simulation (MBS)
Figure 6:BEARINX
It is possible to select friction optimized bearing design, even in the early product development phase.
References• http://www.jbia.or.jp/e/pdf/environment.pdf (Fig : 1, 2, 3, 4 )• http://www.ntn.co.jp/english/products/review/pdf/
NTN_TR79_en_p098_103.pdf (Fig: 5)• http://www.skf.com/group/knowledge-centre/engineering-tools/
skfbearingcalculator.html• http://www.powertransmission.com/issues/0810/bearings.pdf (Fig:
6)• Rolling Bearing Analysis by Tedric A. Harris & Michael N. Kotzales
( FIFTH EDITION ) Page Number: (119 – 211)• Mechanical Design Data Book by V. S. Konnur & A. A. Memon Latest
Second Edition: 2014
Thank You ….