SAE INTERNATIONAL
Smart NVH Solutions for
Next-Generation Brake Design
Gary Weber Application Engineering & Technical Service
Molykote® brand Specialty Lubricants from Dow Corning
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
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
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
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
Tribological Lubrication Regimes
7
Asperity Friction
Hydrodynamic
Friction
Greases
Fluids/oils F
ric
tio
n C
oe
ffic
ien
t
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
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
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
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
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
Fo
rce
, N
Silicone with MoS2
Molykote® G-3407
Caliper Pin Grease
Silicone
with PTFE
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
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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
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
Molykote® D-709 Anti-Friction Coating:
Next-Generation NVH Coating
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• 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 mark Scratch mark
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
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