WORKING OF SAFETY AIR BAGS
AND THEIR MANUFACTURING

By
Sandeep Kuriakose
Design and Manufacturing
Department of Mechanical...
INTRODUCTION TO AIR BAG
An air bag is an bag is an inflatable cushion
An air inflatable
designed
serious injury in the cas...
 AIR BAG SYSTEM
1.

3.

4.

5.

Air bag module

Crash sensor

M. Tech- Design and Manufacturing, NIT
Silchar.

2.

An air ...
AIR BAG SYSTEM WIRING DIAGRAM

M. Tech- Design and Manufacturing, NIT Silchar.

4
HOW AIRBAGS WORK
The crash sensor senses the impact.
2. The diagnosis unit decides.
3. An electric signal is transmitted t...
AIR BAG DEPLOYMENT

A front air bag deployed

M. Tech- Design and Manufacturing, NIT Silchar.

Before deployment

After de...
THE MANUFACTURING OF AIR
BAG
1.

3.
4.
5.

M. Tech- Design and Manufacturing, NIT Silchar.

2.

The propellant
The inflato...
RAW MATERIALS
I.

III.

IV.

Nylon thread

M. Tech- Design and Manufacturing, NIT Silchar.

II.

The air bag:-a woven
nylo...
1.PROPELLANT
The propellant consists of sodium
azide mixed together with an
oxidizer, a substance that helps the
sodium az...
2. INFLATOR ASSEMBLY
The inflator components, such as
the metal canister, the filter
assembly(stainless steel wire
mesh wi...
3. AIR BAG
The woven nylon air bag
fabric is inspected for any
material defects.
 The air bag fabric is then
die cut to t...
4. FINAL ASSEMBLY OF AIR BAG
MODULE
The air bag is then
mounted to the tested
inflator assembly.
 Next, the air bag is
fo...
5. OTHER COMPONENTS
The remaining components of the air bag system—the crash
sensors, the diagnostic monitoring unit, the ...
AIR BAG TESTING

M. Tech- Design and Manufacturing, NIT
Silchar.

This is a test rig which is set up in the laboratory.
14
DEPLOYMENT

M. Tech- Design and Manufacturing, NIT Silchar.

This is a top view of the deployed driver and passenger airba...
CRASH TESTING

Side air bag crash testing

The airbag systems are crash tested under various
temperatures with and without...
REFERENCES
Crouse W. H. and Anglin D. L, Automotive Mechanics,
Tata McGraw - Hill Education (2006).
 Kirpal Singh, Automo...
18

M. Tech- Design and Manufacturing, NIT Silchar.

QUESTIONS ???
19

M. Tech- Design and Manufacturing, NIT Silchar.

THANK YOU
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Working of safety airbags and their manufacturing

  1. 1. WORKING OF SAFETY AIR BAGS AND THEIR MANUFACTURING By Sandeep Kuriakose Design and Manufacturing Department of Mechanical Engineering National Institute of Technology, Silchar. Presented on:-08-09-13
  2. 2. INTRODUCTION TO AIR BAG An air bag is an bag is an inflatable cushion An air inflatable designed serious injury in the case cushion designed to from to of a collision. The protect automobile occupants air bag is part of an inflatable restraint system, also known as from serious injury in the case system (ACRS) or an air cushion restraint of a collision. an air bag supplemental restraint system (SRS), because the air bag is designed to  The air bag is also known as an supplement the protection offered by seat belts. air cushion restraint system (ACRS) or an air bag Read supplemental restraint system (SRS).  This is because the air bag is A car air bag designed to supplement the protection offered by seat belts.  M. Tech- Design and Manufacturing, NIT Silchar. 2
  3. 3.  AIR BAG SYSTEM 1. 3. 4. 5. Air bag module Crash sensor M. Tech- Design and Manufacturing, NIT Silchar. 2. An air bag module Crash sensors. A diagnostic monitoring unit(ECU). A steering wheel connecting coil. Wiring and connectors. 3 Diagnostic monitoring unit Steering wheel connecting coil
  4. 4. AIR BAG SYSTEM WIRING DIAGRAM M. Tech- Design and Manufacturing, NIT Silchar. 4
  5. 5. HOW AIRBAGS WORK The crash sensor senses the impact. 2. The diagnosis unit decides. 3. An electric signal is transmitted to the inflator assembly. 4. The electrical signal then ignites the igniting agent. 5. The gas-generating agent ignites and generates gas. 6. "Airbags" inflate, while the "seatbelt pretensioner" simultaneously fastens the seat belt and absorbs the shock received by the passenger. *Note: actions 1-6 above occur within 50 milliseconds. 1. M. Tech- Design and Manufacturing, NIT Silchar. 5
  6. 6. AIR BAG DEPLOYMENT A front air bag deployed M. Tech- Design and Manufacturing, NIT Silchar. Before deployment After deployment A side air bag deployed The airbag system ignites a solid propellant (NaN3), which burns extreme rapidly to create a large volume of Nitrogen gas to inflate the bag. The bag then literally bursts from its storage site and a second later, the gas quickly dissipates through tiny holes in the bag, thus deflating the bag. 6
  7. 7. THE MANUFACTURING OF AIR BAG 1. 3. 4. 5. M. Tech- Design and Manufacturing, NIT Silchar. 2. The propellant The inflator assembly The air bag Final assembly of air bag module Other components 7 An air bag manufacturing factory
  8. 8. RAW MATERIALS I. III. IV. Nylon thread M. Tech- Design and Manufacturing, NIT Silchar. II. The air bag:-a woven nylon fabric Air bag coating:silicone and urethane The inflator canister or body:-stamped stainless steel or cast aluminum The propellant:-Sodium Azide (NaN3)combined with an oxidizer. A woven air bag Nylon fabric 8 Inflator canister And propellant Applying silicone and urethane coating
  9. 9. 1.PROPELLANT The propellant consists of sodium azide mixed together with an oxidizer, a substance that helps the sodium azide to burn when ignited.  From storage, the sodium azide and the oxidizer are then carefully blended under sophisticated computerized process control in isolated bunkers.  After blending, the propellant mixture is sent to storage. Presses are then used to compress the propellant mixture into disk or pellet form.  M. Tech- Design and Manufacturing, NIT Silchar. 9
  10. 10. 2. INFLATOR ASSEMBLY The inflator components, such as the metal canister, the filter assembly(stainless steel wire mesh with ceramic material inside)and initiator (or igniter) are assembled on a highly automated production line to form inflator sub assembly .  The inflator sub-assembly is combined with the propellant to form the inflator assembly.  The inflator assembly is then tested and sent to storage until needed.  M. Tech- Design and Manufacturing, NIT Silchar. 10 A cut section of inflator assembly
  11. 11. 3. AIR BAG The woven nylon air bag fabric is inspected for any material defects.  The air bag fabric is then die cut to the proper shapes and sewn, internally and externally, to properly join the two sides.  After the air bag is sewn, it is inflated and checked for any seam imperfections.  M. Tech- Design and Manufacturing, NIT Silchar. A die cut air bag fabric to the shape 11 An inflated air bag for checking
  12. 12. 4. FINAL ASSEMBLY OF AIR BAG MODULE The air bag is then mounted to the tested inflator assembly.  Next, the air bag is folded, and the breakaway plastic horn pad cover is installed.  Finally, the completed module assembly is inspected, tested and packaged.  M. Tech- Design and Manufacturing, NIT Silchar. Assembly of an air bag module 12
  13. 13. 5. OTHER COMPONENTS The remaining components of the air bag system—the crash sensors, the diagnostic monitoring unit, the steering wheel connecting coil, and the indicator lamp—are combined with the air bag module during vehicle assembly.  All the components are connected and communicate through a wiring harness.  M. Tech- Design and Manufacturing, NIT Silchar. 13 Connecting air bag module to vehicle
  14. 14. AIR BAG TESTING M. Tech- Design and Manufacturing, NIT Silchar. This is a test rig which is set up in the laboratory. 14
  15. 15. DEPLOYMENT M. Tech- Design and Manufacturing, NIT Silchar. This is a top view of the deployed driver and passenger airbag (Volvo). 15
  16. 16. CRASH TESTING Side air bag crash testing The airbag systems are crash tested under various temperatures with and without loadings on the bag. The results of the test are then fed to the computers where the results are analysed M. Tech- Design and Manufacturing, NIT Silchar. Front air bag crash testing 16
  17. 17. REFERENCES Crouse W. H. and Anglin D. L, Automotive Mechanics, Tata McGraw - Hill Education (2006).  Kirpal Singh, Automobile Engineering, Standard Publishers (2011).  http://www.madehow.com  http://auto.howstuffworks.com  M. Tech- Design and Manufacturing, NIT Silchar. 17
  18. 18. 18 M. Tech- Design and Manufacturing, NIT Silchar. QUESTIONS ???
  19. 19. 19 M. Tech- Design and Manufacturing, NIT Silchar. THANK YOU

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