Gas generator for airbag

• US 7,404,574 B2
• Filed: 12/22/2004
• Issued: 07/29/2008
• Est. Priority Date: 12/22/2003
• Status: Expired due to Fees

• Current Assignee: Daicel Chemical Industries Limited
• Original Assignee: Daicel Chemical Industries Limited
• Inventors: Matsuda, Naoki, Numoto, Kenji, Hirooka, Masoto
• Primary Examiner(s): Fleming; Faye M.
• Application Number:
  US11/017,861
• Publication Number:
  US 20050161923A1
• Time in Patent Office: 1,315 Days
• Field of Search: 280/741, 280/742, 280/740, 280/736
• US Class Current: 280/741
• CPC Class Codes: B60R 2021/0006 Lateral collision
• 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, relating to a gas generator for a side air bag or the like, is provided. The gas generator has an inner cylindrical member stored in a housing, wherein the inner cylindrical member has a second outside diameter portion abutting against the inner peripheral surface of the housing, and a first outside diameter portion smaller in outside diameter than the second outside diameter portion, the tip end of the first outside diameter portion side abuts against the closed end portion (one end portion) of the housing, the filter is provided on the outside of the inner cylindrical member in the radial direction of the first outside diameter portion, and the ignition means is provided on the opposite end portion (the other end) from the closed end portion of the housing.

Claims

1. A gas generator for an airbag, comprising:

a cylindrical housing including at least one gas discharge port in its periphery and having a closed end portion;

an inner cylindrical member in which an interior thereof defines a gas generating agent accommodating space including at least two combustion chambers;

a filter for purifying the gas generated by the combustion of the gas generating agent; and

ignition means for igniting and burning the gas generating agent accommodated in the accommodating space,

wherein the inner cylindrical member comprises a first outside diameter portion and a second outside diameter portion having a larger outside diameter than that of the first outside diameter portion and adapted to be in contact with the inner peripheral surface of the housing, and a second end of the first diameter portion being in contact with the closed end portion of the housing,

the filter is provided radially on an outside of the first outside diameter portion in the inner cylindrical, and

the ignition means is provided on an open end portion of the housing opposite to the closed end portion.

2. The gas generator for an airbag according to claim 1, wherein the two combustion chambers are provided adjacent to each other in an axial direction of the gas generator, and capable of communicating with each other, the first combustion chamber is provided closer to the closed end portion of the housing, and the second combustion chamber is provided closer to the open end portion of the housing, and

the ignition means is provided inside the second combustion chamber, and the gas generating agents charged in the first combustion chamber and second combustion chamber differ from each other in at least one of a charged amount, composition, composition ratio, size, and shape.

3. The gas generator for an airbag according to claim 2, wherein the gas generating agent disposed in the first combustion chamber has the combustion temperature of 1000 to 1700°

C., and the gas generating agent disposed in the second combustion chamber has the combustion temperature of 1700 to 3000°

C.

4. The gas generator for an airbag according to claim 1 or 2, wherein the inner cylindrical member is longer in an axial direction of the gas generator, and at least one opening, that allows communication between the gas generating agent accommodating space and a space defined between the inner cylindrical member and the cylindrical housing is formed in the inner cylindrical member, the opening is formed only in a circumferential surface of the first outside diameter portion.

5. The gas generator for an airbag according to claim 1 or 2, wherein a third outside diameter portion is provided between the first outside diameter portion and the second outside diameter portion, and the third outside diameter portion has a larger outside diameter than that of the first outside diameter portion, and smaller than that of the second outside diameter portion.

6. The gas generator for an airbag according to claim 1 or 2, wherein the ignition means includes an igniter adapted to be actuated by an ignition current, the igniter is attached to a collar member that closes the open end portion of the housing, and an end of the inner cylindrical member closer to the second outside diameter portion abuts against the collar member.

7. The gas generator for an airbag according to claim 1 or 2, wherein the ignition means comprises an igniter adapted to be actuated by an ignition current, the igniter is attached to a collar member that closes the open end portion of the housing, a protrusion is formed on an inner peripheral surface of the housing, and the collar member and an end of the inner cylindrical member closer to the second outside diameter portion abut against the protrusion.

8. The gas generator for an airbag according to claim 1 or 2, wherein a gas discharge port provided on the housing is formed closer to the open end portion of the cylindrical housing than the closed end portion of the housing.

9. The gas generator for an airbag according to claim 1, wherein a length of the first outside diameter portion in a longitudinal direction of the cylindrical housing and a length of the second outside diameter portion in the longitudinal direction of the cylindrical housing are in inverse proportion to a diameter of the first outside diameter portion and a diameter of the second outside diameter portion.

10. The gas generator for an airbag according to claim 5, wherein a length of the first outside diameter portion in a longitudinal direction of the cylindrical housing, a length of the second outside diameter portion in the longitudinal direction of the cylindrical housing, and a length of the third outside diameter portion in the longitudinal direction of the cylindrical housing are in inverse proportion to a diameter of the first outside diameter portion, a diameter of the second outside diameter portion, and a diameter of the third outside diameter portion.

11. The gas generator for an airbag according to claim 1, further comprising:

a partitioning wall that separates the two combustion chambers and being supported by an inner surface of the inner cylindrical member.

12. A gas generator for an airbag, comprising:

a cylindrical housing including at least one gas discharge port in its periphery and having a closed end portion;

an inner cylindrical member in which an interior thereof defines a gas generating agent accommodating space;

a filter for purifying the gas generated by the combustion of the gas generating agent; and

ignition means for igniting and burning the gas generating agent accommodated in the accommodating space,

wherein the inner cylindrical member comprises a first outside diameter portion and a second outside diameter portion having a larger outside diameter than that of the first outside diameter portion and adapted to be in contact with an inner peripheral surface of the housing, and a second end of the first diameter portion being in contact with the closed end portion of the housing,

the filter is provided radially on an outside of the first outside diameter portion in the inner cylinder, and

the ignition means is provided on an open end portion of the housing opposite to the closed end portion, and

a length of the first outside diameter portion in a longitudinal direction of the cylindrical housing and a length of the second outside diameter portion in the longitudinal direction of the cylindrical housing are in inverse proportion to a diameter of the first outside diameter portion and a diameter of the second outside diameter portion.

13. A gas generator for an airbag, comprising:

a cylindrical housing including a gas discharge port in its periphery and having a first end and a second end opposite to the first end;

an inner cylindrical member provided inside the cylindrical housing and defining, therein, an accommodating space, the inner cylindrical member including one end in contact with the first end and provided with at least one opening, all of said at least one opening being provided closer to the first end as compared to the gas discharge port;

a gas generating agent provided inside the accommodating space; and

ignition means for igniting and burning the gas generating agent, the ignition means being provided in the second end.

14. A gas generator for an airbag, according to claim 13, wherein the inner cylindrical member includes a first outside diameter portion and a second outside diameter portion larger than the first outside diameter portion and having an open end in the second outside diameter portion, and the inner cylindrical member is provided inside the cylindrical housing, such that an outer circumstantial portion of the second outside diameter portion is in contact with the inner surface of the cylindrical housing.

15. A gas generator for an airbag, according to claim 13, further comprising:

a projection formed in the inner surface of the cylindrical housing close to the second end,

wherein the ignition means includes a collar provided in an outer side thereof and is located inside the cylindrical housing, such that the collar abuts the projection and the second end of the cylindrical housing deformed inwardly.

16. A gas generator for an airbag, according to claim 13, wherein a space defined inside the inner cylindrical member is in constant communication with a space outside the inner cylindrical member through the at least one opening.