efficient comfort – low drag wet clutches while
TRANSCRIPT
Efficient Comfort –
Low drag wet clutches while maintaining performance
Matt Frary
Missing foundation
Schaeffler Symposium 2014 1 Matt Frary
Torque converter
Transmission
Friction material
Time in hours
Foundation blocks
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0
0.04
0.08
0.12
0.16
1 10 100 1000
Fri
cti
on
co
eff
icie
nt
[µ]
Min
Foundation blocks
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0dv
d
0dv
d
Fri
cti
on
co
eff
icie
nt
[µ]
Slip speed in rpm
Motivation
Improve quality control for Schaeffler customers
Opening the friction material Black box means:
• Understanding parameters that affect performance
• Controlling those parameters
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Development
Dedicated development since 2004
Collaboration with additive suppliers and university
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Current foundation
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0dv
d
0dv
d
Fri
cti
on
co
eff
icie
nt
[µ]
Slip speed in rpm
Can predict and modify functional parameters
Permeability
Surface condition
Material flexibility
ATF modifier
Chemical effects
Surface contact area
Molecule shape and density
0.08
0.09
0.10
0.11
0.12
0.13
0.14
0 0.5 1 1.5 2
Speed in m/s
Torque converter experience
Series production since 2009
1.3 Mio torque converter clutches in production in 2014
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Fri
cti
on
co
eff
icie
nt
[µ] Schaeffler
Competition
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Foundation for transmission clutch
Friction material
Transmission
Transmission Clutch?
Torque converter
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Transmission friction material
0.04
0.08
0.12
0.16
0.20
0.00 0.50 1.00 1.50 2.00 F
ric
tio
n c
oe
ffic
ien
t (µ
)
Speed in m/s 40°C 90°C 120°C
Schaeffler Competitor
0.04
0.08
0.12
0.16
0.20
0.00 0.50 1.00 1.50 2.00
Fri
cti
on
co
eff
icie
nt
(µ)
Speed in m/s 40°C 90°C 120°C
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Shifting clutch foundation
Piston Clutch plates
Carrier Return spring
First planetary automatic
transmission
•Functioning inner and outer splines
•Reduced space
•Reduced cost
Schaeffler Symposium 2014 Matt Frary 11
Carrier
Example production experience
Pierced
flow holes
Bearing
raceways
Riveted
assembly
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Piston and return spring
Integrated
diaphragm
spring
Simple seals
Sheet metal
piston
Riveted
retaining
plate
•Enhanced value assembly
•Reduced space
•Produced since 2009
Piston Clutch plates
Carrier Return spring
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Without
separators
External
separators
Schaeffler
separators
Optimizing function
•Separates all plates
•Only line contact
•No additional parts
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0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
0 200 400 600 800 1000 1200 1400 1600 1800 2000
Dra
g t
orq
ue i
n N
m
Relative velocity in rpm
Without plate separators
With plate separators
Results
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The paradox of clutches
Speed in rpm
0.1mm/facing
0.2mm/facing
0.3mm/facing
0
2
4
6
0 500 1000 1500 2000
To
rqu
e i
n N
m
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The paradox of clutches
0
200
400
600
0 0.5 1 1.5 2
Time in seconds
To
rqu
e i
n N
m
0
2
4
6
8
10
12
14
Pre
ssu
re in
bar
Pre-fill pulse
Possible
torque error
0
100
200
300
400
500
0 10 20 30 40
To
rqu
e i
n N
m
Volume in cc
Schaeffler Symposium 2014 Matt Frary 17
The Challenge for Today's Clutch
0
100
200
300
400
500
0 10 20 30 40
To
rqu
e i
n N
m
Volume in cc
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A New Principle
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Main piston
Rotary
actuator
Ramp ring
Design Concept
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Operation
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•Reduced mass and inertia
•Eliminated acid
•Eliminated adhesive
Softer friction material in
the same overall thickness
A New Manufacturing Potential
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Added function
0
1000
2000
3000
4000
5000
6000
0 0.05 0.1 0.15 0.2 0.25
Fo
rce i
n N
Deflection in mm
SAE#2 Disc
Composite
friction disc
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Stamping technology Two stage piston
Plate separator
Composite facing
Summary
Reduced drag
Reduced mass
Reduced environmental impact
Improved controllability
Riveted assembly
Slim thrust bearing
You can't build a great building on
a weak foundation. You must have
a solid foundation if you're going to
have a strong superstructure.
” “
Gordon B. Hinckley
1910 – 2008
X. Schaeffler Symposium 2014