Arnitel TPE, the most reliable solution for CVJ boots

ARNITEL TPE
®
The most reliable
solution for Constant
Velocity Joint (CVJ)
Boots
Challenges faced in selecting materials for CVJ boots:
Abrasion resistance
Grease and oil resistance
Flexibility at very low temperatures
Endurance at high temperatures
Resistance to flexural fatigue
Freedom of design
ARNITEL TPE IN CVJ BOOTS
Arnitel is the preferred material for constant velocity
The drive shaft is a key part in the car. It transfers
joint (CVJ) boots used by drive train manufacturers
power from the engine to the wheels. Flexible
and supplied to leading vehicle manufacturers who
couplings, such as the constant velocity joint on
have safety, reliability and durability as key require-
front wheel drive vehicles which allows the vehicle to
ments.
change direction, are used at various points in the
drive train.
These couplings are protected from the external
environment by a flexible molding, referred to as a
boot.
Figure 1 CVJ boots.
Boots
In the past, boots were usually made from chloro-
There are basically two types of boots: inboard
prene rubber (CR). However, regular failures due to
boots and outboard boots (also known as CVJ
environmental damage initiated the change to
boots). The typical locations of these two types of
more durable materials.
boots are shown in Figure 2, along with other
protective moldings (bellows) used in the drive
The optimum balance of durability, performance
train. The environmental conditions around the CVJ
and processability that leads to the lowest overall
out- and inboard boots are shown in Figure 3.
system cost especially for more demanding conditions, is provided by copolyester thermoplastic
elastomers such as Arnitel TPE.
Figure 2 Typical locations of protective boots in a car.
Figure 3 Conditions around CVJ outboard and inboard boots.
CVJ outboard boots
CVJ boots have to be resistant to the very high
CR-boot
TPE-E boot
Unit
abrasive conditions created by mud and grime
Cost
structure
coming off the road and to greases used to lubri-
Weight
90
60
g/boot
cate the coupling. Since these boots are mounted
Material
38
38
%
at the wheel, they have to be able to flex at acute
Production
44
17
%
angles in response to any tight turns that the driver
Sub total
82
55
%
makes, retaining their flexibility at all ambient tem-
Large clamp 10
26
%
Small clamp
8
19
%
Total
100
100
%
1.0
1.0
peratures likely to be encountered.
Under extreme environmental conditions, ambient
temperatures can be as low as -40°C, subjecting
Cost
Comparison
the boot to extreme flexural forces at temperatures
where other elastomers would be very brittle, lead-
Table 1 Manufacturing cost structure for CR rubber vs. Arnitel.
ing to failure.
Performance property
4.830e+001
4.347e+001
Performance
ratio of
TPE-E boot
/ CR boot
3.864e+001
3.381e+001
High speed
1.2
2.898e+001
2.415e+001
1.932e+001
1.449e+001
9.659e+000
4.830e+000
1.627e-018
Figure 4 CVJ boot in high angle to the right (full right turn of
the car).
Durability
Room temperature
1.5
Low temperature
2.2
High temperature
1.4
High temperature after aging
2.0
Impact strength
1.4
Weight
0.47
Table 2 Performance benefit in using Arnitel for boots.
Arnitel provides significant performance advantages at
the same manufacturing cost of CR rubber boot.
Design makes it perfect
It is extremely important to design boots correctly
1.000e+00
for optimum boot life, which ideally should be the
9.000e-01
8.000e-01
7.000e-01
life of the car itself.
6.000e-01
5.000e-01
4.000e-01
3.000e-01
Table 1 and table 2 demonstrate the benefits of a
2.000e-01
1.000e-01
0.000e+00
boot made from Arnitel versus CR rubber.
CR Boot
Arnitel enables designers to design boots that are
Arnitel Boot
Figure 5 Redesign of a typical rubber CVJ boot to Arnitel CVJ
boot.
smaller and more compact. This not only brings in
savings through a material cost reduction, but additionally the amount of grease required to lubricate
the coupling is reduced, bringing savings to the car
manufacturer.
An important concern of car manufacturers is that
boots should not generate a squeaking sound dur-
Preliminary Design TPE-E Boot
Compact TPE-E Boot
ing the running-in period of the car. The DSM portfolio contains two grades specially developed to
address this concern.
1.000e+00
1.000e+00
9.000e-01
9.000e-01
8.000e-01
8.000e-01
7.000e-01
7.000e-01
6.000e-01
6.000e-01
5.000e-01
5.000e-01
4.000e-01
4.000e-01
3.000e-01
3.000e-01
2.000e-01
2.000e-01
1.000e-01
1.000e-01
0.000e+00
0.000e+00
Figure 6 CAE redesign of a compact CVJ boot.
Grade
Features
EB463
Durability
High productivity
EB464-01
Higher durability
Anti-squeak
EB464-02
Higher durability
Anti-squeak
Table 3
Standard grade
Compact design grade
THE IDEAL SOLUTION
Arnitel is the ideal solution for CVJ boots
Double the life of CR rubber boot
Greater safety offered
Easier to design
Easier to process
Antisqueaking grades available for highest user comfort
Arnitel is also used for Inboard boots, Rack and pinion bellows and Propeller shaft boots. For more information, please contact your local sales office.
FOR OUTSTANDING
PERFORMANCE
Key properties of Arnitel at a glance
Superior high temperature properties
Resistance to automotive oils and greases
Excellent flexural fatigue resistance
Thermoplastic with excellent processability
Outstanding resistance to creep
Easy to design
Special grades developed to meet different
processes such as injection molding, extrusion
and blow molding
Key applications of Arnitel at a glance
Automotive boots and bellows
Airducts for automobiles
Soft touch applications, ideal for 2 component
Airbag covers with outstanding reliability
molding
High temperature electrical cable sheathing
applications
Regional Contacts
DSM Engineering Plastics
www.dsmep.com
Europe
Americas
Asia
Sittard, The Netherlands
Evansville, IN
Shanghai, China
Tel. 00800-PHONEDSM
Tel. 1-800-333-4237
Tel. 86 21 6386 3080
www.Arnitel.com
Arnitel® is a registered tradename of Royal DSM.

Download Report