Gas generator for air bag

• US 20060088456A1
• Filed: 08/09/2005
• Published: 04/27/2006
• Est. Priority Date: 08/10/2004
• Status: Active Grant

• Current Assignee: Daicel Chemical Industries Limited
• Original Assignee: Daicel Chemical Industries Limited
• Inventors: Matsuda, Naoki, Okuyama, Takashi, Hanano, Teppei
• Granted Patent: US 7,648,163 B2
• Time in Patent Office: Days
• US Class Current: 422/198
• 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
• CPC Class Codes: C06D 5/06 by reaction of two or more solids

Abstract

The present invention provides a gas generator for an air bag in which the weight of a coolant/filter is reduced. The air bag gas generator comprises a housing having a gas discharge port, an ignition means chamber in which ignition means are accommodated, and a combustion chamber in which a gas generating agent is accommodated, a cylindrical coolant/filter disposed between the combustion chamber and the gas discharge port, so that combustion gas passes through the coolant/filter prior to discharge through the gas discharge port, and the air bag gas generator meeting the following requirements (a), (b), and (c): (a) that the gas generating agent have an amount of heat generation of 10 to 30 kcal/mol; (b) that the mass (g) of the coolant/filter in relation to 1 mol of gas generated during combustion of the gas generating agent be 20 to 65 g/mol; and (c) that the coolant/filter have a thickness of not less than 4.0 mm.

Claims

1. A gas generator for an air bag comprising a housing having a gas discharge port, an ignition means chamber in which ignition means are accommodated, and a combustion chamber in which a gas generating agent is accommodated, a cylindrical coolant/filter disposed between the combustion chamber and the gas discharge port so that combustion gas passes through the coolant/filter prior to discharge through the gas discharge port, and the gas generator meeting the following requirements (a), (b), and (c):

(a) that the gas generating agent have an amount of heat generation of 10 to 30 kcal/mol;

(b) that the mass (g) of the coolant/filter in relation to 1 mol of gas generated during combustion of the gas generating agent be 20 to 65 g/mol; and

(c) that the coolant/filter have a thickness of not less than 4.0 mm.

2. The gas generator for an air bag according to claim 1, wherein a ratio between H₁ and H₂ (H₂/H₁), where H₁ is a height from a ceiling surface to a base surface of the housing and H₂ is a height of the cylindrical coolant/filter, is within a range of 0.45 to 0.80.

3. The gas generator for an air bag according to claim 1 or 2, wherein the ignition means comprises an electric igniter that is activated by an ignition current, and a transfer charge that is ignited upon activation of the electric igniter, a gas generating agent having a combustion temperature of 1700 to 3000°

C. is used as the transfer charge, and a gas generating agent having a combustion temperature of 1000 to 1700°

C. is used as the gas generating agent accommodated in the combustion chamber.

4. A gas generator for an air bag, comprising a housing having a gas discharge port, an ignition means chamber in which ignition means are accommodated, and a combustion chamber in which a gas generating agent is accommodated, a cylindrical coolant/filter disposed between the combustion chamber and the gas discharge port, so that combustion gas passes through the coolant/filter prior to discharge through the gas discharge port,

the ignition means chamber formed by an interior space of an inner cylinder disposed in a central portion of the housing, and the ignition means chamber communicating with the combustion chamber via a communication hole provided in a peripheral wall of the inner cylinder, and

the cylindrical coolant/filter supported by a substantially cylindrical retainer fitted into the housing, and the gas generator meeting the following requirements (a) through (d):

(a) that the gas generating agent have an amount of heat generation of 10 to 30 kcal/mol;

(b) that the mass (g) of the coolant/filter in relation to 1 mol of gas generated during combustion of the gas generating agent be 20 to 65 g/mol;

(c) that the coolant/filter have a thickness of not less than 4.0 mm; and

(d) that a ratio between H₁ and H₂ (H₂/H₁), where H₁ is a height from a ceiling surface to a base surface of the housing and H₂ is a height of the cylindrical coolant/filter, be within a range of 0.45 to 0.80.

5. The gas generator for an air bag according to claim 4, wherein the gas discharge port provided in the housing and at least a part of the communication hole provided in the peripheral wall of the inner cylinder to communicate the ignition means chamber with the combustion chamber are provided in mutually opposing height positions in the radial direction, and such that a peripheral wall of the substantially cylindrical retainer exists between the mutually opposing gas discharge port and at least a part of the communication hole.