Airbag module and method of restraining a vehicle occupant with such an airbag module

• US 20070085311A1
• Filed: 10/10/2006
• Published: 04/19/2007
• Est. Priority Date: 10/17/2005
• Status: Active Grant

• Current Assignee: TRW Airbag Systems GmbH (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Original Assignee: TRW Airbag Systems GmbH (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Inventors: Hofmann, Achim, Lutz, Harald, Sponfeldner, Oskar, Lutz, Joachim
• Granted Patent: US 7,246,819 B2
• Time in Patent Office: Days
• US Class Current: 280/739
• CPC Class Codes: B60R 2021/2395 comprising means to control the venting
• CPC Class Codes: B60R 21/239 characterised by their venting means
• CPC Class Codes: B60R 21/276 with means to vent the inflation fluid source, e.g. in case of overpressure B60R21/30 takes precedence; venting means on inflatable member walls B60R21/239

Abstract

An airbag module for a vehicle occupant restraint system includes an airbag (22) and a gas generator (10) that is connected via at least one first outflow opening (18) to an airbag chamber (28), the airbag chamber (28) being at least partially formed by the interior of the airbag (22), an actuator unit (36) being provided on the gas generator (10) and, when the actuator unit (36) is activated, it releases a traction means (50) that causes a pressure reduction in the airbag (22), an activation of the actuator unit (36) also leading to an opening of a second outflow opening (20) in the gas generator (10), which vents generator gas to an environment without this vented gas flowing into the airbag chamber (28). Moreover, the invention relates to a method of restraining a vehicle occupant with such an airbag module.

Claims

1. An airbag module for a vehicle occupant restraint system, comprising an airbag (22) and a gas generator (10) that is connected via at least one first outflow opening (18) to an airbag chamber (28), said airbag chamber (28) being at least partially formed by an interior of said airbag (22), an actuator unit (36) being provided on said gas generator (10) and, when said actuator unit (36) is activated, it releases a traction means (50) that causes a pressure reduction in said airbag (22), an activation of said actuator unit (36) also leading to an opening of a second outflow opening (20) in said gas generator (10), which vents generator gas to an environment without this vented gas flowing into said airbag chamber (28).

2. The airbag module according to claim 1, wherein, when said actuator unit (36) is activated, said traction means (50) initiates at least one of opening at least one airbag opening (54) and releasing an enlarged airbag volume.

3. The airbag module according to claim 1, wherein said actuator unit (36) has a pyrotechnical device (40).

4. The airbag module according to claim 1, wherein said actuator unit (36) has a piston (38) that is installed inside said gas generator (10).

5. The airbag module according to claim 1, wherein together with said actuator unit (36), said gas generator (10) forms a cylinder/piston unit, a piston (38) being moved by an activation of said actuator unit (36), thus opening said second outflow opening (20).

6. The airbag module according to claim 5, wherein said piston (38) has an opening (52), said gas vented through said second outflow opening (20) flowing through said opening (52).

7. The airbag module according to claim 1, wherein said vented gas exits said airbag module when it flows through said second outflow opening (20).

8. The airbag module according to claim 1, wherein said gas generator (10) has a separate base section (12) and a distribution section (14) that are securely connected to each other, said actuator unit (36) being attached to said distribution section (14).

9. The airbag module according to claim 1, wherein at least one airbag opening (54) is provided, a ratio of an outflow cross section of all of said second outflow openings (20) to an outflow cross section of all of said airbag openings (54) being between 1:

2 and 1;

8, preferably between 1;

3 and 1;

5.

10. A method of restraining a vehicle occupant comprising the following steps:

a) activation of a gas generator (10) of a vehicle occupant restraint system in case of a restraint event, whereupon said gas generator (10) feeds gas into an airbag chamber (28) via at least one first outflow opening (18);

b) checking said vehicle occupant position on the basis of sensor data at a prescribed first point in time;

c) activation of an actuator unit (36) if said vehicle occupant is in a position that is unsuitable for a restraint, as a result of which a second outflow opening (20) as well as a traction means (50) are released and a pressure reduction takes place decisively as a result of venting gas into an environment through said second outflow opening (20);

d) assessment of an impact momentum of said vehicle occupant against said airbag based on sensor data at a prescribed second point in time;

e) activation of said actuator unit (36) if said actuator unit (36) was not yet activated in Step c) and if said anticipated impact momentum of said vehicle occupant lies below a predefined limit value, as a result of which said second outflow opening (20) and said traction means (50) are released and a pressure reduction in said airbag (22) takes place decisively as a result of releasing said traction means (50).

11. The method according to claim 10, wherein said first point in time lies between 0 ms and 15 ms after said restraint case has been recognized.

12. The method according to claim 10, wherein said second point in time lies between 25 ms and 40 ms after said restraint case has been recognized.

13. The method according to claim 10, wherein said traction means (50) in Step c) and Step e) releasing at least one of an airbag opening (54) and an enlarged airbag volume.