Efficient Comfort –
Low drag wet clutches while maintaining performance
Matt Frary
Missing foundation
Transmission
Torque converter
Friction material
1
Schaeffler Symposium 2014
Matt Frary
Foundation blocks
Friction coefficient [µ]
0.16
0.12
Min
0.08
0.04
0
1
10
Time in hours
2
Schaeffler Symposium 2014
Matt Frary
100
1000
Foundation blocks
Friction coefficient [µ]
d
0
dv
d
0
dv
Slip speed in rpm
3
Schaeffler Symposium 2014
Matt Frary
Motivation
Improve quality control for Schaeffler customers
Opening the friction material Black box means:
• Understanding parameters that affect performance
• Controlling those parameters
4
Schaeffler Symposium 2014
Matt Frary
Development
Dedicated development since 2004
Collaboration with additive suppliers and university
5
Schaeffler Symposium 2014
Matt Frary
Current foundation
Can predict and modify functional parameters
Friction coefficient [µ]
d
0
dv
d
0
dv
Slip speed in rpm
ATF modifier
Chemical effects
Surface contact area
Molecule shape and density
6
Schaeffler Symposium 2014
Matt Frary
Permeability
Surface condition
Material flexibility
Torque converter experience
Series production since 2009
1.3 Mio torque converter clutches in production in 2014
Friction coefficient [µ]
0.14
0.13
Schaeffler
0.12
0.11
Competition
0.10
0.09
0.08
0
7
Schaeffler Symposium 2014
0.5
Matt Frary
1
Speed in m/s
1.5
2
Foundation for transmission clutch
Transmission
Transmission Clutch?
Torque converter
Friction material
8
Schaeffler Symposium 2014
Matt Frary
Transmission friction material
Schaeffler
Competitor
0.20
Friction coefficient (µ)
Friction coefficient (µ)
0.20
0.16
0.12
0.08
0.04
0.00
0.50
1.00
1.50
2.00
0.16
0.12
0.08
0.04
0.00
0.50
Speed in m/s
40°C
9
Schaeffler Symposium 2014
90°C
Matt Frary
1.00
1.50
Speed in m/s
120°C
40°C
90°C
120°C
2.00
Shifting clutch foundation
First planetary automatic
transmission
Clutch plates
Return spring
10
Schaeffler Symposium 2014
Matt Frary
Piston
Carrier
Carrier
•Functioning inner and outer splines
Example production experience
•Reduced space
•Reduced cost
Riveted
assembly
Bearing
raceways
11
Schaeffler Symposium 2014
Matt Frary
Pierced
flow holes
Piston and return spring
Sheet metal
piston
•Enhanced value assembly
•Reduced space
Integrated
diaphragm
spring
•Produced since 2009
Riveted
retaining
plate
Simple seals
Clutch plates
Piston
Return spring
12
Schaeffler Symposium 2014
Matt Frary
Carrier
Optimizing function
Without
separators
External
separators
Schaeffler
separators
•Separates all plates
•Only line contact
•No additional parts
13
Schaeffler Symposium 2014
Matt Frary
Results
1.6
Without plate separators
Drag torque in Nm
1.4
1.2
1
0.8
0.6
0.4
With plate separators
0.2
0
0
200
400
600
800
1000 1200 1400 1600 1800 2000
Relative velocity in rpm
14
Schaeffler Symposium 2014
Matt Frary
The paradox of clutches
Torque in Nm
6
0.1mm/facing
4
0.2mm/facing
0.3mm/facing
2
0
0
500
1000
Speed in rpm
15
Schaeffler Symposium 2014
Matt Frary
1500
2000
The paradox of clutches
14
Possible
torque error
12
Torque in Nm
10
400
8
6
200
4
Pre-fill pulse
2
0
0
0
0.5
1
Time in seconds
16
Schaeffler Symposium 2014
Matt Frary
1.5
2
Pressure in bar
600
The Challenge for Today's Clutch
Torque in Nm
500
400
300
200
100
0
0
10
20
30
Volume in cc
17
Schaeffler Symposium 2014
Matt Frary
40
A New Principle
Torque in Nm
500
400
300
200
100
0
0
10
20
30
Volume in cc
18
Schaeffler Symposium 2014
Matt Frary
40
Design Concept
Rotary
actuator
Main piston
19
Schaeffler Symposium 2014
Matt Frary
Ramp ring
Operation
20
Schaeffler Symposium 2014
Matt Frary
A New Manufacturing Potential
•Reduced mass and inertia
•Eliminated acid
•Eliminated adhesive
Softer friction material in
the same overall thickness
21
Schaeffler Symposium 2014
Matt Frary
Added function
6000
SAE#2 Disc
5000
Force in N
4000
3000
Composite
friction disc
2000
1000
0
0
0.05
0.1
0.15
Deflection in mm
22
Schaeffler Symposium 2014
Matt Frary
0.2
0.25
Summary
Two stage piston
Stamping technology
Riveted assembly
Plate separator
Slim thrust bearing
Composite facing
Reduced drag
Reduced mass
Reduced environmental impact
Improved controllability
23
Schaeffler Symposium 2014
Matt Frary
“
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