2. 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
3. Introduction
Rolling 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.
4. 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.
5. Improves Fuel Economy and National
Economy
Protects the Environment
Conserves Resources
Significance
6. Illustration by examples
Contribution of Bearing to overall vehicle fuel efficiency
Energy Conservation by Rolling
Figure 1: Comparison of energy consumption for vehicles with and without rolling
bearings.
7. 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
8. 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.
9. 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
10. Selection For Fuel Efficient Bearings at Normal
Conditions
Bearing Location: Gearbox Shaft
Analytically Test were Conducted For Three Bearings
Deep Groove Ball Bearings
Double Row Angular Contact Bearings
Taper Roller Bearings
Constant Parameter: Fa=3250N, Fr=4000N, n=1750 RPM,
Shaft Orientation- Horizontal,
Lubricant Viscosity- (120 – 12 ) mm²/s
13. 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 kN
Lubricant viscosity: 23.3 mm ²/s
Conventional bearings
Improved bearing I
Improved bearing II
Runningtorque
Nm
·
Speed (rpm)
14. Suggestion For Fuel Efficient Bearings
by Optimized Design
Figure 5:Taper roller bearings
15. 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.
16. Total Friction Torque Calculation Formula
Applied
Total Friction Torque
M=MM=Mll+M+Mvv+M+Mff
Total Friction Loss (H)=0.001M.Total Friction Loss (H)=0.001M.ωω
n: Rotation Speedn: Rotation Speed
MMll : 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
17. 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
18. Taper Roller Bearings
• M=3.35*10-8
G(nvo)1/2
(ftFr/K)1/3
• M=3.35*10-8
G(nvo)1/2
Fa
1/3
• G=dm
1/2
D1/6
(Z.l)2/3
(sinα)-1/3
• F
r
/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.
22. 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.
23. Analytical Model for calculating and
minimizing friction of Roller Bearings
• Catalog Method
• Highly specialized Multi Body Simulation (MBS)
24. Figure 6:BEARINX
It is possible to select friction optimized bearing
design, even in the early product development phase.
25. 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
