Gas generator for air bag and air bag apparatus

• US 20020056976A1
• Filed: 01/07/2002
• Published: 05/16/2002
• Est. Priority Date: 11/30/1998
• Status: Active Grant

• Current Assignee: Daicel Chemical Industries Limited
• Original Assignee: Daicel Chemical Industries Limited
• Inventors: Ohji, Nobuyuki, Nakashima, Yoshihiro
• Granted Patent: US 6,598,901 B2
• Time in Patent Office: Days
• US Class Current: 280/741
• CPC Class Codes: B01D 2279/10 for air bags, e.g. inflators therefor
• CPC Class Codes: B01D 46/24 Particle separators, e.g. dust precipitators, using rigid hollow filter bodies
• CPC Class Codes: B01D 46/2403 characterised by the physical shape or structure of the filtering element
• CPC Class Codes: B60R 2021/01006 Mounting of electrical components in vehicles
• 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 small in size and which can be produced easily with a simple structure is provided. The output of a gas generator is equalized so that an occupant can be safely restrained, and the combustion performance can be stably adjusted. The gas generator comprises a housing forming an outer shell container and accommodating two or more ignition units to ignite upon an impact and two or more gas generating agents which are independently ignited and burnt by the ignition units to generate a combustion gas for inflating an air bag, and a plurality of gas discharge ports which are formed in the housing, wherein the gas discharge ports are closed by sealing units for maintaining an internal pressure of the housing to the given pressure, a breaking pressure for breaking the sealing units is adjusted in multiple stages by controlling gas discharge ports and/or sealing units, and a difference of the maximum internal pressures in the housing at activation of the respective igniters is suppressed.

Claims

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

a housing forming an outer shell container and having first and second gas discharge ports;

a first combustion chamber provided within said housing for accommodating first gas generating means'"'"';

a second combustion chamber provided within said housing for accommodating second gas generating means;

a first ignition means ignited, upon an impact to burn the first gas generating means to inflate the air bag;

a second ignition means for selectively ignited, upon the impact, to burn the second gas generating means to inflate the air bag; and

first and second sealing means for closing the first and second gas discharge ports, respectively, to maintain an internal pressure of the housing to a given pressure,

wherein the first combustion chamber, in which the first gas generating means starts burning first and the second combustion chamber, in which the second gas generating means starts burning later, are partitioned by a wall having a communication hole, the communication hole is provided with flame-transfer-preventing means that prevents the second gas generating means in the second combustion chamber from burning due to the combustion of the first gas generating means in the first combustion chamber.

2. A gas generator for an air bag according to claim 1, wherein the flame-transfer-preventing means is a sealing member.

3. A gas generator for an air bag according to claim 2, wherein the sealing member seals the communication hole at the side of the first combustion chamber.

4. A gas generator for an air bag according to claim 2 or 3, wherein the flame-transfer-preventing means is a seal tape which seals the communication hole at the side of the first combustion chamber.

5. A gas generator for an air bag according to claim 2 or 3, wherein the flame-transfer-preventing means is a sealing plate.

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

a housing forming an outer shell container and having a plurality of gas discharge ports;

a first combustion chamber provided within said housing for accommodating first gas generating means;

a second combustion chamber provided within said housing for accommodating second gas generating means;

first ignition means ignited, upon an impact, to burn the first gas generating means to inflate the air bag;

second ignition means selectively ignited, upon the impact, to burn the second gas generating means to inflate the air bag; and

sealing means attached to said gas discharge ports for maintaining an internal pressure of the housing to the given pressure,

wherein the first combustion chamber in which the first gas generating means starts burning first is partitioned from the second combustion chamber in which the second gas generating agent starts burning later, and

wherein combustion gas generated in the first combustion and combustion gas generated in the second combustion chamber pass through different passages and reach the plurality of gas discharge ports.

7. A gas generator for an air bag according to claim 6, wherein different passages are formed by passage forming members provided within said housing.