Gas generator for air bag and air bag device

• US 6,412,815 B1
• Filed: 07/13/2000
• Issued: 07/02/2002
• Est. Priority Date: 09/28/1998
• Status: Expired due to Term

• Current Assignee: Daicel Chemical Industries Limited
• Original Assignee: Daicel Chemical Industries Limited
• Inventors: Ohji, Nobuyuki, Iwai, Yasunori, Katsuda, Nobuyuki, Nakashima, Yoshihiro
• Primary Examiner(s): Dickson, Paul N.
• Application Number:
  US09/554,740
• Time in Patent Office: 719 Days
• Field of Search: 280/736, 280/741, 280/742, 102/530, 102/531
• US Class Current: 280/736
• CPC Class Codes: B01D 2279/10 for air bags, e.g. inflators therefor
• CPC Class Codes: B01D 46/2411 Filter cartridges
• CPC Class Codes: B60R 2021/01006 Mounting of electrical components in vehicles
• CPC Class Codes: B60R 2021/26029 Ignitors
• CPC Class Codes: B60R 2021/26064 characterised by auto-ignition means
• CPC Class Codes: B60R 2021/2633 with a plurality of inflation levels
• CPC Class Codes: B60R 2021/2648 comprising a plurality of combustion chambers or sub-chambers
• CPC Class Codes: B60R 21/2644 using only solid reacting substances, e.g. pellets, powder

Abstract

A gas generator for an air bag system has, in a housing provided with a gas discharge port, ignition means activated upon an impact, and gas generating means ignited and burnt by the ignition means and generate a combustion gas for inflating an air bag, and two combustion chambers storing the gas generating means. The combustion chambers are concentrically provided so as to be adjacent to each other in the radial direction of the housing, and a communicating hole which allows communication between the combustion chambers is provided, in the housing. The gas generator also has two igniters, two different gas generating means, a connector having a lead wire, a combustion chamber, ignition means provided in an inner cylindrical member, and an automatic ignition member, which can effectively restrain an occupant.

Claims

1. A gas generator for an air bag, comprising:

a housing having a gas discharge port;

an inner cylindrical member provided within said housing along an axial direction of said housing, said inner cylindrical member defining, outside thereof, a first combustion chamber, and also defining, inside thereof, a second combustion chamber and an ignition means accommodation chamber;

first ignition means provided within said ignition means accommodation chamber and activated upon an impact to ignite directly only gas generating means within said first combustion chamber to inflate the air bag; and

second ignition means provided within said ignition means accommodation chamber and selectively activated upon the impact to ignite directly only gas generating means within said second combustion chamber to inflate the air bag.

2. A gas generator for an air bag according to claim 1, wherein said first combustion chamber and said second combustion chamber are provided within said housing such that said second combustion chamber is surrounded by said first combustion chamber.

3. A gas generator for an air bag according to claim 1 or 2, further comprising:

coolant means, for cooling combustion gas generated by combustion of the gas generating means, provided within said first combustion chamber concentrically with respect to a central axis of said housing.

5. A gas generator for an air bag according to claim 1, wherein a communicating hole which allows mutual communication between said first combustion chamber and said second combustion chamber is provided in the housing.

7. A gas generator for an air bag according to any one of claims 1, 4, 5, and 6, wherein said first ignition means and said second ignition means includes a first igniter and a second igniter, respectively, and the first igniter and the second igniter are attached to a single initiator collar.

8. A gas generator for an air bag according to claim 7, wherein said first ignition means includes a transfer charge, provided in isolation from the second igniter, ignited and burnt only upon activation of the first igniter.

9. A gas generator for an air bag according to claim 3, further comprising:

a flow path forming member provided within said housing for introducing combustion gas generated in the first combustion chamber and combustion gas generated in the second combustion chamber to said coolant means via different flow paths.

10. A gas generator for an air bag according to claim 9, wherein the combustion gas generated in the first combustion chamber and the combustion gas generated in the second combustion chamber passes through the gas discharge port after passing through said coolant means.

11. A gas generator for an air bag according to claim 3, wherein the combustion gas generated in the first combustion chamber and the second combustion chamber pass through the same coolant means.

12. A gas generator for an air bag according to claim 7, wherein the first igniter and the second igniter are supported by an igniter fixing member that covers an upper surface of the single initiator collar.

13. A gas generator for an air bag according to claim 7, wherein the first igniter and the second igniter are provided in the single initiator collar such that a central axis of the first igniter and a central axis of the second igniter are parallel to a longitudinal axis of the housing.

14. A gas generator for an air bag according to claim 7, wherein a central axis of said first ignition means is parallel to a central axis of said second ignition means.

15. A gas generator for an air bag according to claim 1, wherein said inner cylindrical member is concentrically provided with respect to a central axis of said housing.

16. A gas generator for an air bag according to claim 1, wherein said first ignition means is isolated from and said second ignition means.

17. A gas generator for an air bag according to any one of claims 1, 4, 5, and 6, wherein the first combustion chamber surrounds the ignition means accommodation chamber, and the second combustion chamber is provided adjacent to the ignition means accommodation chamber in the axial direction of said housing.

18. A gas generator for an air bag according to any one of claims 1, 4, 5, and 6, wherein at least one of a burning rate, a composition, a composition ratio, and an amount of the gas generating means provided in the first combustion chamber is different from those of the gas generating means provided in the second combustion chamber.

19. A gas generator for an air bag according to any one of claims 1, 4, 5, and 6, wherein the first ignition means includes a first igniter and the second ignition means includes a second igniter,

wherein an operating output of the first igniter is different from an operating output of the second igniter.

20. A gas generator for an air bag according to any one of claims 1, 4, 5, and 6, wherein the first ignition means and the second ignition means include a first igniter and a second igniter, respectively, activated by an electric signal, and lead wires are connected to the first igniter and the second igniter for transmitting the electrical signal and extend in the same direction along the same plane.

21. A gas generator for an air bag according to claim 20, wherein the lead wires are respectively connected to the igniter via a first connector and a second connector, and the first connector and the second connector are arranged in parallel on the same plane.

22. A gas generator for an air bag according to claim 21, wherein the lead wires extend in the same direction perpendicular to a longitudinal axial direction of the housing via the first connector and the second connector.

23. A gas generator for an air bag according claim 21, wherein the first connector and the second connector have shapes peculiar to the first igniter and the second igniter, respectively such that the first connector can be connected only to the first igniter and the second connector can be connected only to the second igniter.

24. A gas generator for an air bag according to claim 23, wherein positioning means is provided in the first connector and the second connector such that shapes of the first connector and the second connector are different from one another.

25. A gas generator for an air bag according to claim 24, wherein the positioning means is one of a groove and a projection formed in at least one of the first connector and the second connector so as to be different in at least one of a position and a shape thereof at each connected igniter.

26. A gas generator for an air bag according to claim 1 or 4, further comprising:

a sectioning circular member engaging with a stepped notch portion provided on an inner peripheral surface of the inner cylindrical member; and

a seal cup member engaging with the sectioning circular member provided within said inner cylinder member, wherein a peripheral edge of the seal cup member is bent and fitted into a groove provided on the inner peripheral surface of the inner cylindrical member.

27. A gas generator for an air bag according to claim 26, wherein the second ignition means includes a second igniter activated by an electric signal and is attached to an initiator collar by an igniter fixing member which covers the upper surface of the initiator collar, the seal cup member has an igniter receiving port extended to the igniter fixing member, an O-ring is provided in a space formed by the igniter fixing member, the igniter receiving port, and the second igniter, and the O-ring seals between the igniter fixing member and the igniter receiving port, between the igniter fixing member and the second igniter, and between the igniter receiving port and the second igniter.

28. A gas generator for an air bag according to any one of claims 1, 4, 5, and 6, wherein the gas generating means provided within said first combustion chamber and said gas generating means provided within said second combustion chamber are burnt at different timings from one another, and an automatic igniting material (AIM) ignited and burnt by transmission of heat generated by combustion of a previously burnt gas generating agent, is arranged in at least one of the first combustion chamber and the second combustion chamber where gas generating means, burnt at a delayed timing, is stored.

4. A gas generator for an air bag, comprising:

a cylindrical housing having a gas discharge port and being longer in an axial direction thereof than in a radial direction thereof;

a partition wall provided within said housing in a direction substantially perpendicular with respect to the axial direction of the housing, said partition wall defining, within said housing, a first combustion chamber and an ignition means accommodation chamber at a first side thereof, and also defining, within said housing, a second combustion chamber at a second side thereof;

a first ignition means provided within said ignition means accommodation chamber and selectively activated upon an impact to ignite directly only gas generating means disposed inside said first combustion chamber; and

a second ignition means provided within said ignition means accommodation chamber and activated upon the impact to ignite directly only gas generating means disposed inside said second combustion chamber.

6. A gas generator for an air bag according to claim 4, wherein a communicating hole which allows mutual communication between the first combustion chamber and the second combustion chamber is provided in the housing.

29. A gas generator for an air bag according to claim 4, further comprising:

coolant means, provided within said housing, for cooling combustion gas generated in said first combustion chamber and said second combustion chamber; and

a coolant means accommodating chamber, provided within said housing adjacent said second combustion chamber opposite said first combustion chamber, for accommodating said coolant means.

30. An air bag apparatus, comprising:

a gas generator for an air bag having,

a housing having a gas discharge port and provided, therein,

an inner cylindrical member provided within said housing along an axial direction of said housing, said inner cylindrical member defining, outside thereof, a first combustion chamber, and also defining, inside thereof, a second combustion chamber and an ignition means accommodation chamber,

first ignition means provided within said ignition means accommodation chamber and activated upon an impact to ignite directly only gas generating means within said first combustion chamber to inflate the air bag, and

second ignition means provided within said ignition means accommodation chamber and selectively activated upon the impact to ignite directly only gas generating means within said second combustion chamber to inflate the air bag;

an impact sensor for detecting an impact and activating the gas generator;

an air bag to introduce a gas generated in the gas generator and inflate; and

a module case for storing the air bag.