Efficient Comfort – Low drag wet clutches while

Efficient Comfort –

Low drag wet clutches while maintaining performance

Matt Frary

Missing foundation

Schaeffler Symposium 2014 1 Matt Frary

Torque converter

Transmission

Friction material

http://sweetclipart.com/multisite/sweetclipart/files/check_mark_green.png


Time in hours

Foundation blocks


0

0.04

0.08

0.12

0.16

1 10 100 1000

Fri

cti

on

co

eff

icie

nt

[µ]

Min

Foundation blocks


0dv

d

0dv

d

Fri

cti

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[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


Development

Dedicated development since 2004

Collaboration with additive suppliers and university


Current foundation


0dv

d

0dv

d

Fri

cti

on

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[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


Fri

cti

on

co

eff

icie

nt

[µ] Schaeffler

Competition

Schaeffler Symposium 2014 Matt Frary 8

Foundation for transmission clutch

Friction material

Transmission

Transmission Clutch?

Torque converter





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


Shifting clutch foundation

Piston Clutch plates

Carrier Return spring

First planetary automatic

transmission

•Functioning inner and outer splines

•Reduced space

•Reduced cost


Carrier

Example production experience

Pierced

flow holes

Bearing

raceways

Riveted

assembly


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






Without

separators

External

separators

Schaeffler

separators

Optimizing function

•Separates all plates

•Only line contact

•No additional parts


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


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


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


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


A New Principle


Main piston

Rotary

actuator

Ramp ring

Design Concept


Operation


•Reduced mass and inertia

•Eliminated acid

•Eliminated adhesive

Softer friction material in

the same overall thickness

A New Manufacturing Potential


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


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

Documents

Efficient Comfort – Low drag wet clutches while