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Airbag System Airbag Cushions (Mounting Location: Steering Wheel, Dashboard) Requirements and Test Conditions

TL 825 12

Konzernnorm Descriptors: airbag, airbag system, airbag module, steering wheel, airbag cushions dashboard

D

Preface The contents of Team Supply Specification AK-LV 02 (May 2005) have been adopted without changes by Technical Supply Specification TL 825 12. AK-LV 02 was drafted by the "Supply Specifications" team of the automobile companies Audi AG, Bayerische Motoren Werke AG, Daimler Chrysler AG, Porsche AG and the Volkswagen AG. Changes The following changes have been made as compared to TL 825 12, 1999-09: ─

see change documentation for AK-LV 02

Previous issues 1997-11; 1999-09 Additional in-house requirements ─

Approval of first supply and changes according to Volkswagen standard VW 011 55.

─

Avoidance of hazardous substances according to VW 911 01.

─

Design according to drawing or performance specifications.

─

Sections marked with a documentation bar " The documents shall be kept on file for 15 years.

Norm vor Anwendung auf Aktualität prüfen / Check standard for current issue prior to usage.

July 2005

" are subject to mandatory documentation.

Referenced standards VW 011 55

Vehicle Supply Parts; Approval of First Supply and Changes

VW 911 01

Environmental Standard for Vehicles; Vehicle Parts, Materials, Operating Fluids; Avoidance of Hazardous Substances

as well as all documents referred to in AK-LV 02.

QUELLE: NOLIS

The English translation is believed to be accurate. In case of discrepancies the German version shall govern. Numerical notation according to ISO practice (see VW 01000).

Klass.-Nr. /Class. No. 8F M5 1

Continued on 21 pages of AK-LV 02 Fachverantwortung/Responsibility E2SR/4

H. Rindfleisch

Normung/Standards (EZTD, 1733) Tel: +49-5361-9-31528

O. Guse

Tel: +49-5361-9-32438

Sobanski

Confidential. All rights reserved. No part of this document may be transmitted or reproduced without prior permission of a Standards Department of the Volkswagen Group. Parties to a contract can only obtain this standard via the B2B supplier platform “www.vwgroupsupply.com”. .

 VOLKSWAGEN AG

Team Supply Specification May 2005

Airbag System Airbag Cushions (Mounting Location: Steering Wheel, Dashboard)

AK - LV 02

Requirements and Test Conditions airbag system; airbag cushions (installation location: steering wheel, dashboard); requirements and test procedures

Contents 1

Scope and aim

2

Definitions

3

General

4 4.1 4.2 4.3 4.4

General requirements and their test conditions for the airbag cushion Marking Volume High pressure air permeability Visual requirements

5 5.1 5.2 5.3 5.4 5.5 5.6 5.7

Fabric requirements and their test conditions Preface Requirements Testing equipment Test condition Test method Test procedure Airbag cushion aging

6 6.1 6.2 6.3

Seam requirements and their test conditions Circumference seam/seam between the jacket portion and the side portion Tear seam requirements and their test conditions Rebound strap requirements and their test conditions

7

Referenced standards and specifications

8

Previous issues

9

Changes

Continued on pages 2 to 22 AK-LV: Team Supply Specification Team of companies: Audi AG, Bayerische Motoren Werke AG, DaimlerChrysler AG, Porsche AG and Volkswagen AG

Page 2 AK-LV 02 : 2005-05 1

Scope and aim

This specification is intended to ensure the product quality and function of the airbag cushion within the overall system to which it belongs by providing precise, clear and uniform guidelines for its properties. The specification also describes the test methods used to document airbag cushion requirements and their implementation. The specification is a part of the drawing. The specification applies to all airbag cushions that have a note in the drawing indicating this.

2

Definitions

The airbag cushion is part of a restraint system. It is filled with gas when the gas generator detonates, thus ensuring increased occupant safety in the event of a collision.

3

General

The manufacturer shall ensure that the provisions in this specification and the drawing are observed. This is documented along with the process reliability and must be demonstrated with suitable methods and a sufficient test scope. Alternative test methods are permissible, as long as they facilitate equally suitable verification. The examining body must provide documentation that its tests correlate with the test methods described in this specification. Unless otherwise indicated, these requirements apply to parts in as-received condition (with no prior load). Deviations must be noted in the test report. If a requirement bears only the note "see drawing", the applicable value shall be taken from the drawing. If the drawing does not contain any related information, the requirement can be omitted. In the case of a discrepancy between the drawing and the specification, the entry in the drawing takes precedence. In general, the airbag cushion must conform to all requirements listed in this specification. This conformity must be documented in the release or first-sample test. The airbag cushion is subject to mandatory documentation. The standard-production tests required to ensure proper functioning are subject to mandatory documentation; the test records must be kept on file for 20 years. A clear assignment between the airbag cushion and data subject to mandatory documentation must be guaranteed.

The sections of this specification marked with a documentation bar or a "D" are subject to mandatory documentation.

Page 3 AK-LV 02 : 2005-05 4

General requirements and their test conditions for the airbag cushion

The proper department must be informed of any changes to the airbag cushion and/or manufacturing methods and manufacturing locations before they are introduced in standard production; these changes require a new release. The airbag cushion undergoes an environmental simulation once installed in the module. After testing it must meet the requirements after the module environmental simulation as well as the airbag cushion requirements.

4.1

Marking

An easy-to-read and permanent marking must be applied to the airbag cushion. This marking must show the manufacturer and the warp direction as well as permit retracing of the components and manufacturer parameters.

4.2

Volume

The volume of the airbag cushion shall be determined using a suitable measuring method. The measuring method shall be coordinated with the customer. Alternatively, calculation methods are permitted. If possible, the method described below shall be used. 4.2.1

Preface

This test is used to determine the airbag cushion volume of a finished airbag. 4.2.2

Requirements

Volume:

see drawing

Page 4 AK-LV 02 : 2005-05 4.2.3

Test fixtures

To perform the test, a base container is required with a volume corresponding to that of the airbag cushion in order to hold the hollow balls (see Table 1 and Table 2, for example). When dimensioning the container, the bulk volume of the hollow balls used must be taken into consideration. Table 1: Container 1, dimensions Interior dimensions in mm

Volume

Width

Depth

Height

in liters

Base container:

300

500

545/375

69 ± 0,5

Measurement container:

200

100

500

10 ± 0,1

Interior dimensions in mm

Volume

Table 2: Container 2, dimensions

Width

Depth

Height

in liters

Base container:

600

500

370/543

138 ± 0,5

Measurement container:

200

100

500

10 ± 0,1

4.2.4

Test condition

Test temperature: Hollow balls, without edges: Material: Wall thickness: Measuring setup: 4.2.5

RT ∅ (20 ± 0,2) mm PP 0,5 mm see Figure 1

Test procedure

The airbag cushion volume is determined using a hollow ball measurement. The airbag cushion openings must be closed such that no hollow balls can escape. The mouth of the airbag cushion is clamped suspended freely on the funnel. The airbag cushion is then filled with hollow balls from the store container until no more balls can be pressed into the airbag cushion. The hollow balls remaining in the store container are poured into the measurement container and the remaining volume is measured.

Airbag cushion volume = base volume – residual volume

Page 5 AK-LV 02 : 2005-05

hollow balls Hohlkugeln

base container Grundbehälter

funnel Trichter

Figure 1. Measuring setup for volume measurement

4.3

4.3.1

High pressure air permeability

Preface

This test is used to determine the total flow rate of a finished airbag cushion. This test is only conducted upon special request, because it can aid in the calculation. 4.3.2

Requirements

The flow rate of the airbag cushion must be determined and a tolerance zone established using statistical methods (see Table 3). Table 3: Tolerance zone value pairs using a sample airbag cushion design as an example Airbag cushion internal pressure [bar]

0,02

0,04

0,06

0,08

0,10

0,12

0,14

0,16

0,18

0,20

0,22

0,24

0,26

0,28

0,30

Upper limit [g/s]

83,9

121,5

159,1

196,7

234,3

271,9

309,5

347,1

384,7

422,3

459,9

497,5

539,1

572,7

610,3

Lower limit [g/s]

76,5

113,2

149,8

186,5

223,3

259,8

296,5

333,1

369,8

406,5

443,1

479,8

516,5

553,5

589,8

Page 6 AK-LV 02 : 2005-05 700

Mass flow rate [g/s] [g/s] Massenstrom

600

500

400

300

200

100

0 0

0,05

0,1

0,15

0,2

0,25

0,3

0,35

Bag-Innendruck [bar] [bar] Airbag cushion internal pressure

Figure 2. Tolerance zone of the high pressure air permeability for a sample airbag cushion design Refer to the drawing for further tolerance zones. The visual requirements must be met before and after the high pressure air permeability test. 4.3.3

Test fixtures

A system according to Figure 3 is needed to conduct the test. pvor

airbag cushion Luftsack

T pi

p Beruhigungsstrecke smoothing path

diffusor Diffusor

5

100 100

1000

50 500

Meßblendeorifice measuring

Figure 3. System for the flow rate measurement

run-out path Auslaufstrecke

Page 7 AK-LV 02 : 2005-05

4.3.4

Test condition

Test temperature: 4.3.5

RT

Test procedure

The airbag cushion shall be tested according to the drawing status. The airbag cushion to be measured is secured to a system according to Figure 3. The system is supplied with compressed air via a compressed air system. The over-pressure pi that builds up in the airbag cushion is measured in comparison to the atmospheric pressure. At the same time, the mass flow rate Qm of the air flowing through is measured using the metering orifice method according to DIN 1952. The following applies to the measuring setup: Measuring orifice outside diameter: Measuring orifice inside diameter:

100 mm 50 mm

During the test, the following measured variables are recorded using suitable registering instruments: – – – –

Measuring orifice admission pressure (absolute pressure) padm Pressure difference at the measuring orifice ∆p Temperature behind the measuring orifice Airbag cushion internal pressure pi

A linear fitted line with a correlation coefficient > 0,995 must be plotted through the airbag cushion internal pressure/mass flow rate value pairs determined. The fitted line must be within the tolerance zone defined according to Table 3 (see Figure 2 for example).

Page 8 AK-LV 02 : 2005-05 4.4

4.4.1

Visual requirements

Preface

This test is used to detect visible airbag cushion flaws. 4.4.2

Requirements

The airbag cushion shall not have any breaks or tears in the fabric. During a normal visual inspection, the fabric shall not exhibit any flaws that adversely affect the function. The airbag cushion fabric must not have any manufacturing flaws of any kind that could adversely affect the processing and functional characteristics. 4.4.3

Test condition

Test temperature: 4.4.4

RT

Testing equipment

The airbag cushion is evaluated in accordance with ASTM D-5426. 4.4.5

Test procedure

The test is a standard visual inspection. Fold points shall be examined for breaks and tears using a magnifying glass with 6 times enlargement.

Page 9 AK-LV 02 : 2005-05 5

Fabric requirements and their test conditions

5.1

Preface

The tests serve to determine the characteristics of the fabrics used to make the airbag cushions.

5.2

Requirements

The fabric requirements listed in Table 4 shall be determined and tested by the supplier and entered and documented with the occurring tolerances in the table. This sheet shall be maintained by the supplier. The supplier guarantees through its component and system trials that the integrity requirements are fulfilled with the documented fabric tolerances.

5.3

Testing equipment

Suitable proofs of calibration shall be documented for the test equipment used.

5.4

Test condition

Test temperature:

5.5

Standard climate according to ISO 139

Test method

If the tests cannot be conducted exactly according to DIN standards, the deviations must be noted in the test report. 5.5.1

Bending stiffness

The test is conducted according to DIN 53 350, separately for warp and weft directions. Depending on the fabric used, the test method according to ASTM D-4032 can also be used if required. 5.5.2

Needle tear-out force/comb extraction force

The test is conducted according to DIN 54 301, but with 20 mm edge spacing and 50-mm-wide specimens. Depending on the material used, tests according to DIN 53331 or ASTM D-6479 can also be used. 5.5.3

Change in dimensions influenced by temperature

The test is conducted according to DIN EN ISO 3759. In addition to this standard, the following applies: Temperature: Duration: Apparatus: Specimen setup: Specimen dimensions:

105 C ° 60 min Forced ventilation drying cabinet Place on a grate without tension 600 mm x 600 mm

Page 10 AK-LV 02 : 2005-05 5.5.4

Fabric thickness

The test is conducted according to DIN EN ISO 5084. In addition to this standard, the following applies: Test area: Test pressure: 5.5.5

25 cm² 2-5 cN/cm²

Tear propagation strength

The test is conducted according to DIN EN ISO 13937-2. Evaluation according to ISO 6133, Method B, with F>10% N. The specimen size used must be indicated. 5.5.6

Weight per unit area

The test is conducted according to DIN 3801. Deviating from the standard, specimens with 100 cm² surface area shall be used. 5.5.7

Burn test

The test is conducted according to FMVSS 302. The test must be conducted both in the warp and weft directions. 5.5.8

Air permeability

The test is conducted according to DIN EN ISO 9237. Deviating from the standard, the following applies: Test area: Pressure differential:

100 cm² 500 Pa

The supplementary air outlet, which is suggested as optional in the standard, is obligatory here; the value to be subtracted must be specified. Distribution of the measuring points: see Figure 4.

Page 11 AK-LV 02 : 2005-05

Figure 4. Distribution of the measuring points across the web width for the air permeability test.

5.6

Test procedure

The measurement specimens must be uniformly taken across the width.

Page 12 AK-LV 02 : 2005-05 Table 4:

Sample completed data sheet as used to document fabric requirements (to be completed and documented by the supplier)

3

Type A Fabric Requirements Type

Fiber manufacturer/ raw material

A1 A2

Akzo Nobel PA 6.6 DuPont Nylon 6.6 Rhone Poulenc PA 6.6

A3 A4 A5 No.

D

Test feature

EN445 HRT T 725 T 644

470 f 72 470 f 68 470 f 68

L 1/1 L 1/1 L 1/1

Unit

Desired value

Total from warp, weft

Added later

Bending stiffness

DIN 53 350, ASTM D-4032

Nmm²

1 2

Thread count

DIN EN 1049-2

Warp Weft

Threads/dm Threads/dm

225 ± 10 210 ± 10

3

Maximum tensile strength/elongation

DIN 53 857, Part 1

3.1

As-received condition

DIN 53 857, Part 1

N/5 cm N/5 cm

% %

≥ 2 800 ≥ 2 800

3.2

Environmental simulation

DIN 53 857, Part 1

Warp Weft Warp Weft Warp Weft Warp Weft

N/5 cm N/5 cm

% %

≥ 2 500 ≥ 2 500

Warp Weft

43 ± 7 35 ± 7

mm/min

≤ 100

N N

≥ 250 ≥ 250

% %