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Smart NVH solutions for next generation brake design


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Noisy brakes are already the number one cause of complaint, and warranty claims, from car owners. And with next generation brake design requiring new materials to deal with extremes of temperature, load and speed, it’s never been more important to address the triple threat of noise, vibration and harshness (NVH).

Presented as part of the renown SAE International webinar series, Dow Corning thought leader Gary Weber discusses the NVH issues emerging through innovation in brake design and the lubricants that can solve them.

Discover real-life application examples and experimental evidence, as well as specific techniques for damping, isolation and absorption.

Discover the smart specialty brake lubricants that are reducing brake drag and rolling, increasing the service life of components and providing effective barriers against chemical, mechanical, thermal and electrical stress.

And if you found this presentation useful, don’t forget to share it and join the discussion below.

Published in: Automotive
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Smart NVH solutions for next generation brake design

  1. 1. SAE INTERNATIONAL Smart NVH Solutions for Next-Generation Brake Design Gary Weber Application Engineering & Technical Service Molykote® brand Specialty Lubricants from Dow Corning
  2. 2. Discussion Outline • Evolution of Automotive Brake Systems • Next-Generation Design Trends and Challenges • Tribological Lubrication Regimes • Range of Smart Lubrication™ Solutions • Examples of Smart NVH Solutions for Brakes • Proactive Design to Minimize Brake NVH • Q & A 2
  3. 3. Evolution of Automotive Brake Systems 3 • Reducing residual brake drag • Regenerative braking • Stop-start systems braking • Autonomous emergency braking (AEB) Next-generation design trends and challenges Drum brake and mechanical parking brake Caliper is introduced and parking brake is integrated into drum brake Proliferation of electronics into braking system
  4. 4. Smart Science Drives Mobility Innovation™ 4 Energy Efficiency Connectivity & Safety Comfort & Design Eliminate/reduce NVH Material & temperature capability Vehicle system longevity Brake performance Fuel economy/efficiency Lightweighting Legislative & consumer pull Brake by wire Autonomous emergency braking Reduce brake drag and rolling resistance Meet or exceed regulatory limits on solvents and additives Ensure compatibility with different design materials – elastomers, plastics and metals Provide “lifetime” lubrication solutions for controlling noise, vibration and harshness Improve component service life and reliability with optimized friction- control Enhance lubricant resistance to chemical, mechanical, thermal and electrical stresses Improve resistance to extreme heat, corrosion and oxidation TRENDS INDUSTRY FOCUS BRAKE NVH LUBRICANTS
  6. 6. Using Tribology to Solve Brake NVH OEM/Supplier Design Needs: • Brake NVH performance is critical for: − Improving user experience (UX) − Reducing vehicle warranty claims Smart Solutions: • Tribology (study of friction, wear and lubrication) identifies different lubrication regimes for addressing brake NVH performance – from the pedal to the pad • Stribeck Curve – basis of tribology 6
  7. 7. Tribological Lubrication Regimes 7 Asperity Friction Hydrodynamic Friction Greases Fluids/oils FrictionCoefficient Total Friction Film Friction Hydrodynamic Lubrication (3 ≤ λ) Brake System Lubrication 3 Boundary Friction Solid lubes Pastes AFCs Mixed Friction Greases w/solids Dispersions Boundary Lubrication (0 ≤ λ ≤ 1) Mixed Lubrication (1 ≤ λ ≤ 3) STRIBECK CURVE 1 2
  8. 8. Specialty Lubricant Solutions 8 Greases Pastes Oils Compounds Dispersions Anti-Friction Coatings Lubricating fluid, thickening agent, additives Grease-like with high percentage of solid lubricants Lubricating fluids with specialty additives Grease-like silicone fluids with silica filler Finely dispersed solids in lubricating fluids “Lubricating paints”; cure to form dry, solid lubricant coatings bonded to the surface
  9. 9. Using Tribology to Reduce Brake NVH • Breaking down NVH − Noise  acoustics − Vibration  transmitted feel − Harshness  sound quality and occupant perception • Approach for NVH reduction − Damping – allow smooth and consistent operation − Isolation – prevent fretting, stick-slip, seizure − Absorption – materials of construction, material compatibility • What is the smart way to tackle surface engineering and tribology issues related to brake system NVH? − With specialty lubricants 9
  10. 10. Specialty Lubricants Aid in Smart Brake Design • Greases provide damping to allow smooth and consistent operation and performance at temperature extremes • Solid lubricants create isolation between contacting surfaces to prevent stick-slip, seizure and corrosion • Compounds act as absorption mediums to interrupt the sound path from source to receiver − Materials of construction and material compatibility are key considerations 10
  11. 11. Greases as Smart NVH Solutions for Brakes Guide Pin Lubrication Requirements • Eliminate fretting corrosion, sticking and binding • Reduce excessive pin wear causing noise and operation issues • Prevent high-temperature seizure and reduced braking power Proven, Effective Solutions • Silicone or PAG (polyalkylene glycol) greases ‒ Rubber/metal and metal/metal pairings ‒ Elastomer compatibility at elevated temperatures (150ºC) ‒ Low frictional force ‒ Good compatibility with brake fluids 11 0 5 10 Time, min 0 20 40 60 80 100 Force,N Silicone with MoS2 Molykote® G-3407 Caliper Pin Grease Silicone with PTFE
  12. 12. Greases as Smart NVH Solutions for Brakes Electric Parking Brake • Lubrication of polymer gear sets ‒ Multiple gear reductions • Material compatibility is key – brake fluid, polymer, elastomer • Dielectric capability Proven, Effective Solutions • PAO and PAG (polyalkylene glycol) greases ‒ Polymer/metal and polymer/polymer pairings ‒ Performance over entire lubrication regime ‒ Low frictional force; high-pressure performance ‒ DOT3 and DOT4 brake fluid compatible 12
  13. 13. Molykote® G-1074 Grease: A Noise-Damping EP Grease 13 30% reduction in noise versus competitive offering Extreme-pressure capabilities and noise-damping abilities allow Molykote® G-1074 Grease to excel in high-speed polymer-based gear trains. Property tested, unit Competitor A Competitor B Molykote® G-1074 Grease OK load, N 300; 200; 100 500; 600; 800 1,000; 1,000; 900 Temperature: 50˚C; stroke: 1 mm; frequency: 50 Hz; test ball: SUJ-2; test disk: SUJ-2, procedure A *Data variations are acceptable based on ASTM D5706, #11. Precision and Bias. Repeatability is less than 0.7X at 95% probability, where X = the average of two results, N. Molykote® G- 1074 Grease has much greater extreme-pressure value than Competitors A and B.* Molykote® G- 1074 Grease Competitor A Competitor B SRV extreme-pressure test results – ASTM D5706 Noise test results vs. Competitor A Molykote® G-1074 Grease Competitor A Property tested, unit Molykote® G-1074 Grease Competitor A Average noise, dB 50.2 53.3
  14. 14. Smart NVH Solutions for Shims and Clips Brake Shims and Abutment Clip Coatings • Travel path for brake noise • Reduce and control friction and wear • Ensure quiet and consistent pad movement Proven, Effective Solutions • Solid lubricants of pastes and anti-friction coatings ‒ Performance over wide temperature range ‒ Noise-damping and vibration absorption capacity ‒ Minimizing vibrations due to DTV ‒ Excellent corrosion protection 14 Coefficient of friction 36 N load and 10 Hz TIME, SECONDS
  15. 15. Molykote® D-709 Anti-Friction Coating: Next-Generation NVH Coating 15 • Molykote® D-709 Anti-Friction Coating exhibits 3x wear life versus Molykote® D-708 Anti-Friction Coating • Greater wear resistance and lower CoF than competitive offerings • Silver color to minimize appearance of coating scratches TEST CONDITIONS Load: 9.8 N Stroke: 4 mm Speed: 100 osc/min Ball: 1/2 inch SUJ2 steel Test temperature: Room temperature LOAD AF COATING SUS #304 PLATE Lubricity (oscillation test) Molykote® D-708 Anti-Friction Coating Competitor A Molykote® D-709 Anti-Friction Coating Cross-cut test Molykote® D-708 Anti-Friction Coating Molykote® D-709 Anti-Friction Coating Scratch markScratch mark
  16. 16. Considerations for Proactive Design to Minimize Brake NVH • Vehicle cabin continually becoming quieter • Innovative materials bring new tribological challenges • Materials of construction are KEY in system design − Lightweight alloys; fibers and composites • Root causes of unacceptable brake NVH include inadequate lubrication, high friction or excessive wear • Temperature, load, speed – all reaching new extremes − Lubricant solution needs to be compatible with all materials Specialty lubricants – smart, effective solutions for approaching next-generation design 16
  17. 17. Questions? BOOTH 431 SEPTEMBER 25-28 The Westin Kierland Resort & Spa Scottsdale, Arizona
  18. 18. The information contained in this communication does not constitute an offer, does not give rise to binding obligations, and is subject to change without notice to you. The creation of binding obligations will occur only if an agreement is signed by authorized representatives of Dow Corning and your company. Any reference to competitor materials contained in this communication is not an endorsement of those materials by Dow Corning or an endorsement by the competitor of Dow Corning materials. To the fullest extent permitted by applicable law, Dow Corning disclaims any and all liability with respect to your use or reliance upon the information. DOW CORNING DOES NOT MAKE ANY WARRANTY OR REPRESENTATION, EXPRESS OR IMPLIED, WITH RESPECT TO THE UTILITY OR COMPLETENESS OF THE INFORMATION AND DISCLAIMS THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. DOW CORNING DISCLAIMS LIABILITY FOR ANY INCIDENTAL OR CONSEQUENTIAL DAMAGES. Dow is a registered trademark of The Dow Chemical Company. Dow Corning is a registered trademark of Dow Corning Corporation. The Corning portion of the Dow Corning trademark is a trademark of Corning Incorporated, used under license. Molykote is a registered trademark of Dow Corning Corporation. Smart Science Drives Mobility Innovation is a trademark of Dow Corning Corporation. All other trademarks are the property of their respective owners. © 2016 Dow Corning Corporation, a wholly owned subsidiary of The Dow Chemical Company. All rights reserved. Form No. 80-8166-01