AIR BAG GAS GENERATOR AND AIR BAG DEVICE

• US 20020167155A1
• Filed: 07/10/2000
• Published: 11/14/2002
• 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 6,547,275 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

The present invention provides a gas generator in which the entire size of a container is small, the generator can be produced easily with a simple structure, the output of a gas generator is equalized so that an occupant can be safely restrained, and the combustion performance can be stably adjusted.

A gas generator for an air bag comprises a housing forming an outer shell container and accommodating two or more ignition means to ignite on an impact and two or more gas generating means which are to be independently ignited and burnt by the ignition means so as 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 means for maintaining an internal pressure of the housing to the given pressure, a breaking pressure for breaking the sealing means is adjusted at multiple stages by controlling gas discharge ports and/or sealing means, 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 accommodating two or more ignition means to ignite on an impact and two or more gas generating means which are to be independently ignited and burnt by the ignition means so as to generate a combustion gas for inflating an air bag, and a plurality of gas discharge ports which are formed in the housing and closed by sealing means for maintaining an internal pressure of the housing to the given pressure, wherein a breaking pressure for breaking the sealing means is adjusted at multiple stages by two or more gas discharge ports and/or two or more sealing means.

2. A gas generator for an air bag according to claim 1, a difference in maximum internal pressures in the housing at the time of activation of the respective ignition means is suppressed.

3. A gas generator for an air bag according to claim 1 or 2, wherein a ratio of different breaking pressures with respect to the gas discharge ports being next to each other in pressure for breaking the sealing means is 1.1/1 or greater.

4. A gas generator for an air bag according to any one of claims 1 to 3, wherein the breaking pressure is adjusted by arranging two or more kinds of opening diameters and/or opening areas of the gas discharge ports.

5. A gas generator for an air bag according to claim 4, wherein the opening diameter is 1 to 8 mm.

6. A gas generator for an air bag according to claim 4 or 5, wherein among two kinds or more of gas discharge ports formed in the housing, with respect to two kinds being next to each other in size of the opening diameter, a ratio between the larger diameter-having gas discharge port and a small diameter-having is 4/1 to 1.1/1 and/or a ratio in opening area is 97/3 to 3/97.

7. A gas generator for an air bag according to any one of claims 1 to 3, wherein the breaking pressure is adjusted by arranging two or more kinds of thicknesses of the sealing means.

8. A gas generator for an air bag according to claim 7, wherein the opening diameter is 1.1 to 8 mm.

9. A gas generator for an air bag according to claim 7 or 8, wherein among the sealing means having two or more kinds of thicknesses, with respect to two kinds of sealing means being next to each other in thickness, a thickness ratio between them is 1.1/1 to 12/1.

10. A gas generator for an air bag according to any one of claims 7 to 9, wherein adjustment of the breaking pressure is performed by setting an area ratio of the two kinds or more of gas discharge ports having different areas that are sealed by the sealing means having two or more different thicknesses is 97/3 to 3/97.

11. A gas generator for an air bag according to any one of claims 1 to 3, wherein the breaking pressure is adjusted by arranging two or more kinds of opening diameters and/or opening areas of the gas discharge ports, and by arranging two or more kinds of thicknesses of the sealing means.

12. A gas generator for an air bag according to claim 11, wherein the opening diameter is 1 to 8 mm.

13. A gas generator for an air bag according to claim 11 or 12, wherein adjustment of the breaking pressure is performed by setting an area ratio of the two kinds or more of discharge ports which are sealed by the sealing means having two or more different thicknesses is 97/3 to 3/97.

14. A gas generator for an air bag according to any one of claims 1 to 13, wherein the sealing means comprises a seal layer having a thickness of 20 μ

m to 200 μ

m, an bonding layer or a adhesive layer having a thickness of 5 to 100 μ

m.

15. A gas generator for an air bag according to any one of claims 1 to 14, wherein each of the gas generating means for generating the combustion gas is accommodated in individual combustion chamber and independently ignited by the respective ignition means, and a flame by combustion of one gas generating means is not transferred to the other gas generated means.

16. A gas generator for an air bag according to claim 14, wherein the gas generating means accommodated in the respective combustion chamber has a different surface area per unit weight from each other.

17. A gas generator for an air bag according to claim 1, wherein in the housing, two combustion chambers storing the gas generating means are concentrically provided so as to be adjacent in the radial direction of the housing, and a communicating hole which allows communication between the combustion chambers is provided.

18. A gas generator for an air bag according to claim 1, wherein the housing is formed into a cylindrical shape having an axial core length longer than an outermost diameter, the housing is provided at its peripheral wall with a plurality of gas discharge ports, two combustion chambers storing the gas generating means are concentrically provided so as to be adjacent in the axial direction and/or a radial direction of the housing, and a communication hole which allows communication between the combustion chambers is provided.

19. A gas generator for an air bag according to claim 1, wherein the respective igniters constituting the ignition means are provided in one initiator collar so as to be aligned to each other in the axial direction.

20. A gas generator for an air bag according to claim 19, wherein the ignition means comprises a transfer charge to be ignited and burnt on activation of the igniter, the transfer charge is partitioned for each igniter and independently ignited and burnt at each igniter, and the gas generating means accommodated in the two combustion chambers are ignited and burnt by flame respectively caused by combustion of the transfer charge in different section.

21. A gas generator for an air bag according to any one of claims 1 to 20, wherein the two or more ignition means include igniters which are to be respectively activated on electric signals, the igniters are provided in one initiator collar so as to be aligned to each other in the axial direction, and each igniter is arranged eccentrically with respect to the center axis of the housing.

22. A gas generator for an air bag according to any one of claims 1 to 21, wherein the two or more ignition means include igniters which are to be respectively activated on electric signals, lead wires for transmitting the electric signals are respectively connected to the igniters, and the lead wires are taken out in the same direction on the same plane.

23. A gas generator for an air bag according to any one of claims 1 to 22, wherein the two or more ignition means include igniters which are to be respectively activated on electric signals, lead wires for transmitting the electric signals are respectively connected to the igniters via connectors, and the connectors are arranged in the same direction on the same plane.

24. A gas generator for an air bag according to any one of claims 1 to 23, wherein the two or more ignition means include igniters which are to be respectively activated by electric signals, lead wires for transmitting the electric signals are respectively connected to the igniters via connectors, and the lead wires are taken out in the same direction perpendicular to the axial direction of the housing by the connector.

25. A gas generator for an air bag according to any one of claims 1 to 24, wherein the two or more ignition means include igniters which are to be respectively activated by electric signals, lead wires for transmitting the electric signal are respectively connected to the igniter by connectors, and the connectors have positioning means capable of connecting to only one of the igniters.

26. A gas generator for an air bag according to claim 25, wherein the positioning means is formed into a connector shape which is different at each connected igniter.

27. A gas generator for an air bag according to claim 25 or 26, wherein the positioning means is a groove and/or a projection which is formed in the connector so as to be different in a position and/or a shape at each connected igniter.

28. An air bag apparatus comprising:

a gas generator for an 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,

wherein the gas generator for the air bag is the gas generator for the air bag according to any one of claims 1 to 27.

29. A method of controlling gas generation, comprising

adjusting a breaking pressure for breaking the sealing means at multiple stages by two or more gas discharge ports and/or two or more sealing means in a gas generator for an air bag comprising a housing forming an outer shell container and accommodating two or more ignition means to ignite on an impact and two or more gas generating means which are to be respectively ignited and burnt by the ignition means so as to generate a combustion gas for inflating an air bag, and a plurality of gas discharge ports which are formed in the housing and closed by sealing means for maintaining an internal pressure of the housing to the given pressure.

30. A gas generator for an air bag, comprising a housing forming an outer shell container and accommodating two or more ignition means to ignite on an impact and two or more gas generating means which are to be respectively ignited and burnt by the ignition means so as to generate a combustion gas for inflating an air bag, and a plurality of gas discharge ports which are formed in the housing and closed by sealing means for maintaining an internal pressure of the housing to the given pressure, wherein a first combustion chamber which starts burning first and a second combustion chamber which starts burning later are partitioned by a wall having a communication hole, the communication hole is provided with flame-transfer-preventing means so that the combustion in the second combustion chamber should not be caused by the combustion in the first combustion chamber.

31. A gas generator for an air bag according to claim 30, wherein the flame-transfer-preventing means is a sealing member.

32. A gas generator for an air bag according to claim 31, wherein the sealing member seals the communication hole on the side of the first combustion chamber.

33. A gas generator for an air bag according to claim 31 or 32, wherein the flame-transfer-preventing means is a seal tape which seals the communication hole on the side of the first combustion chamber.

34. A gas generator for an air bag according to claim 31 or 32, wherein the flame-transfer-preventing means is a sealing plate.

36. A gas generator for an air bag according to claim 35, wherein different passages are formed by passage forming members.

35. A gas generator for an air bag, comprising a housing forming an outer shell container and accommodating two or more ignition means to ignite on an impact and two or more gas generating means which are to be respectively ignited and burnt by the ignition means so as to generate a combustion gas for inflating an air bag, and a plurality of gas discharge ports which are formed in the housing and closed by sealing means for maintaining an internal pressure of the housing to the given pressure, wherein the first combustion chamber which starts burning first is partitioned from the second combustion chamber which starts burning later, and the gases generated in the respective combustion chambers pass through different passages and reach the gas discharge ports.