〉〉New Products

Automotive Wires
With the World’s Highest Level of Wear Resistance

INTRODUCTION
1.1. INTRODUCTION
It is said that the automotive industry is currently in oncein-a-century revolutionary time. The automotive electrification and the self-driving are certainly advancing. The
number of wires used for the wire harnesses in a car are
by the thousands and are still increasing with the automobile electronification. Since it is possible to have damages on the wires because of their contacts with metal orresin parts, the wires which might be damaged are protected by a tube covering them. The wire harness, known
as the nerves of the automobile, is a bundle of wires
which has many functions such as transmitting signals ofengine controlling or of data from the several sensors, or
supplying electricity to the lamps, and it can be estimatedthat the automotive electrification and the self-driving will
make its functions more complex and important.
Therefore, the wire harness will require further weight
reduction, downsizing, and also resource saving for environmental considerations.
With our material technology developed over the years
and our unique new chemical cross-linking technology,
we have developed the automotive heat resistant wire,with a very high wear resistance compared to conventional products, which complies with The Japanese
Automotive Standards Organization(JASO) Standards.
This developed wire has a wear resistance which is
8 times higher than the JASO Standard value and also
has excellent performances even under the severer conditions. With these characteristics, it makes it possible toreduce the protective tube used for the wire harnesses
and it can be expected not only the weight reduction, thedownsizing, and the resource saving of the wire harnesses but also the reduction of the numbers of assemblingworks.

2.

the wear in a tape test.
Another type is the adhesive wear, shown in Figure 2, awear form where the material is sheared on the frictional
interface and then the part of the sheared material develops friction particles.
For example, in the scrape test for wear resistance,
which testing machine is shown in Figure 3, as the roundwire moves back and forth across the surface of the wire
(test sample), the wear is developed in a complex form
which has effects of an abrasive wear and also an adhesive wear.

Figure 1 The wear type: the abrasive wear.

Figure 2 The wear type: the adhesive wear.

THE WEAR RESISTANCE OF THE WIRE

The wire is exposed to the vibration of driving or of theengine over its usage lifetime. Therefore it is criticallyrequired to be wear resistant.
There are many different types of wears. One exampleof them is the abrasive wear, a wear form where the surface of the wire is scraped off mainly by foreign objects
developed on the frictional interface, as shown in Figure 1.
It is considered that this type of wear is a major cause ofFigure 3 The scrape testing machine for wear resistance.

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Automotive Wires With the World’s Highest Level of Wear Resistance

The JASO Standards defines the wear properties forthe tape and the scrape for the wear property of wires
used for the wire harnesses. The wear property test for
the tape consists of the tape which has a frictional surface with a defined size and a hardness of the particle is
moved in one direction and the wear resistance of thewire jacket is evaluated. The wear property test to thescrape is that round wire is moved back and forth on thetest sample wire under constant load and the wear resistance is measured.

3.

Wear cycle numbers / times

Cooling boad
Glass plate

DEVELOPMENT OF THE AUTOMOTIVEWIRES WITH WEAR RESISTANCE

With the material development in consideration of thetypes of the wear described above, we have developed
the automotive wires which have the world’s highest levelof wear resistance. Our new cross-linking technology features the strong binding of resin’s molecular chain. With
this technology, we have succeeded in improving theresistance dramatically against the stress received
repeatedly from the frictional interface. Moreover, wehave achieved the prevention of deformities on the surface layer by enhancing the cohesion of components andwithstanding the wear by reducing friction.
As shown in Figure 4, we have achieved the strength of
8 times the standard value required by the JASO D 625-3
standard for the scrape wear performance.
900

The scrape wear test（0.3 mm2 wire）

Specimens

Oil tank

Figure 5 Fogging test.

5.

JASO EVALUATION OF THE WEARRESISTANCE WIRE

The characteristic of the developed wire is shown in Table 1.
With all items of this characteristic, such as not only thewear resistance and fogging resistance but also themechanical strength, the heat resistance, the environment
resistance and others, it is obvious that this wire satisfies
the characteristic required by the JASO D 625 standard.

800

Table 1700
600

Standard value:
more than
100 times

400
300
200
1000

JASO D 625 standard evaluation result.
Item500

Conventional
product

Developed
product

Figure 4 The scrape strength comparison.

4.

ency is maintained. It is less likely to fog the front glass or
the resin components which are requiring transparency, it
can be said that this wire product is usable irrespective ofthe location.

FOGGING OF THE WEAR RESISTANCE
WIRE

The developed automotive wire achieves high fogging
resistance by reducing volatile portions of low-molecularweight materials.
The fogging test is measured in accordance with theprocedure defined in JASO 6452. As shown in Figure 5,
specimens of the wire jacket material are set in a glass
container and covered it with a glass plate. The glass
container is heated up to 100˚C in the oil tank, while theglass plate lid is cooled down and the degree of the fogging of the glass is measured after 3 hours.
It is confirmed that the degree of the fogging of theglass in the developed wire is quite little and its transpar-

Test condition

Insulation resistance 70℃ for 2 hours, 4.5 m

Developed product(0.3mm2)
3 × 1016 Ωmm

Tensile strength

50 mm, 200 mm/min

22.6 MPa

Elongation

̶234%

Heat deformation

120 ℃ for 4 hours

Pass

Sticking force

50 mm, 250 mm/min

23N

Low temperaturewinding-40℃ for 4 hours

Pass

Low temperature
Impact-15℃, load 100 kgf

PassScrape wear

7 N, SUS wire

856 times

Heat resistance 1B

150℃ for 10 days

Pass

Heat resistance 1C

Self diameter winding
200℃ for 30 min

Pass

Heat shrink

150℃ for 15 min

0.1 mmImmersion

Gasoline
Light diesel oil
Engine oil
EthanolPower steering oil
Automatic transmission
fluid oilLong life coolant

Pass
Pass
Pass
Pass
Pass

Battery liquidresistance―Pass

Flame retardant

Horizontal firing

Pass

Degree ofcross-linking

Xylene 120℃ for 24 min

55%

Pass
Pass

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Automotive Wires With the World’s Highest Level of Wear ResistanceCompared with the characteristics of conventional
automotive wires, the developed wire has no inferiority
point on its each characteristic and it is obvious that it
has excellent characteristic with respect to its wear resistance.

6.

Conventional product:Protecting the wire by the protection tube

CONCLUSION

The wire which we developed this time is achievable, withits high wear resistance, with the aim of reducing the protective tube component of wire harnesses (Figure 6).
Therefore, it makes the components simplified andreduced their weight. In the future, with the advantages ofthis high wear and heat resistance wires, we consider that
we can contribute to a reduction of the space by thinning
the wire diameter.
In conclusion to this article, our new cross-linking technology used for this developed product achieves not only
the resource saving of the components by improving its
wear resistance but also reducing the electricity requiredin the cross-linking process.
By reducing CO2 emissions in the manufacturing process also, we will extend this manufacturing technique ofthe heat-resistant wire with the wear resistance, whichlead to the reduction of impact on climate change, overthe manufacturing of other products.

Developed product: TubelessFigure 6 Tubeless wire harness.

For more information, please contact:
Electronic Appliance Wire Department,
Optical Fiber & Cable Products Division,Communications Solutions Division
TEL: +81-3-6281-8573
Contact form:
https://www.furukawa.co.jp/srm/form/index.php?id=enwiring

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