Air bag gas generator and air bag apparatus

• US 20020063420A1
• Filed: 07/20/2000
• Published: 05/30/2002
• Est. Priority Date: 09/28/1998
• Status: Active Grant

• Current Assignee: Nobuyuki Katsuda, Nobuyuki Ohji, Yasunori Iwai, Yoshihiro Nakashima
• Original Assignee: Nobuyuki Katsuda, Nobuyuki Ohji, Yasunori Iwai, Yoshihiro Nakashima
• Inventors: Katsuda, Nobuyuki, Ohji, Nobuyuki, Iwai, Yasunori, Nakashima, Yoshihiro
• Granted Patent: US 6,460,883 B1
• Time in Patent Office: Days
• US Class Current: 280/736
• 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 2021/26029 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

The present invention relates to an air bag system, and particularly relates to a gas generator having two or more combustion chambers, namely, a gas generator for an air bag having, in a housing with a gas discharge port, an ignition means to be activated on an impact, and gas generating means which is to be ignited and burnt by the ignition means and generate a combustion gas for inflating an air bag, wherein two combustion chambers storing the gas generating means 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. Additionally, the present invention relates to a gas generator including two igniters, a gas generator including two different gas generating means, a gas generator including an igniter having a lead wire, a gas generator having a combustion chamber and ignition means in an inner cylindrical member, and a gas generator including an automatic ignition member, which can effectively restrain an occupant.

Claims

1. A gas generator for an air bag, having an ignition means to be activated on an impact, and gas generating means which is to be ignited and burnt by the ignition means and generate a combustion gas for inflating an air bag in a housing with a gas discharge port, 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.

2. A gas generator for an air bag according to claim 1, wherein coolant means for cooling a combustion gas generated by combustion of the gas generating means is further disposed in a peripheral wall side of the housing in the combustion chamber on the outer side in the radial direction.

5. A gas generator for an air bag according to any one of claims 1 to 4, wherein the ignition means comprises two or more igniters to be activated on an impact, and the respective igniters are provided in one initiator collar so as to be aligned to each other in the axial direction.

6. A gas generator for an air bag according to claim 5, wherein the ignition means comprises a transfer charge to be ignited and burnt on activation of the igniter, and the transfer charge is partitioned for each igniter and independently ignited and burnt at each igniter.

7. A gas generator for an air bag according to claim 6, wherein the gas generating means stored in the two combustion chambers are respectively ignited and burnt by flames generated by combustion of the transfer charge in the respective sections.

8. A gas generator for an air bag according to any one of claims 1 to 7, wherein one combustion chamber of the two combustion chambers is provided in the axial direction of the ignition means and the other combustion chamber is provided in the radial direction of the ignition means.

9. A gas generator for an air bag according to any one of claims 1 to 8, wherein the gas generating means which are different from each other in at least one of a burning rate, a composition, a composition ratio and an amount, are stored in the two combustion chambers, respectively.

10. A gas generator for an air bag according to any one of claims 1 to 9, wherein combustion gases generated due to combustions of the gas generating means stored in the two combustion chambers reach a gas discharge port via different flow paths at the respective combustion chambers, and the gas generating means stored in one combustion chamber is not directly ignited on the combustion gas generated in the other combustion chamber.

11. A gas generator for an air bag according to claim 10, wherein a flow path forming member is arranged in the housing so as to form a flow path, thereby introducing the combustion gas generated in one combustion chamber to the coolant means as it is.

12. A gas generator for an air bag according to any one of claims 1 to 11, wherein the ignition means comprises two or more igniters to be activated on an impact, and the igniters are supported by an igniter fixing member which covers upper surfaces of initiator collars, and fixed to one initiator collar.

13. A gas generator for an air bag according to any one of claims 1 to 12, wherein the igniters are provided in one initiator collar being aligned to each other in the axial direction, and each igniter is arranged eccentrically with respect to the center axis of the housing.

14. A gas generator for an air bag according to any one of claims 1 to 13, wherein the ignition means comprises two or more igniters to be activated on an impact, and the respective igniters are different in operating output.

15. A gas generator for an air bag according to any one of claims 1 to 14, wherein the ignition means comprises two or more igniters to be activated by an electric signal, lead wires for transmitting the electrical signal are respectively connected to the igniter, and the lead wires are taken out in the same direction on the same plane.

16. A gas generator for an air bag according to any one of claims 1 to 15, wherein the ignition means comprises two or more igniters to be activated by an electric signal, lead wires for transmitting the electrical signal are respectively connected to the igniter via connectors, and the connectors are arranged in parallel on the same plane.

17. A gas generator for an air bag according to any one of claims 1 to 16, wherein the ignition means comprises two or more igniters to be activated by an electric signal, lead wires for transmitting the electrical signal are respectively connected to the igniter via connectors, and the lead wires are taken out in the same direction perpendicular to the axial direction of the housing by the connector.

18. A gas generator for an air bag according to any one of claims 1 to 17, wherein the ignition means comprises two or more igniters to be activated by an electric signal, lead wires for transmitting the electrical signal are respectively connected to the igniters by connectors, and the connectors have positioning means capable of connecting to only one of the igniters.

19. A gas generator for an air bag according to claim 18, wherein the positioning means is formed into a connector shape which is different at each connected igniter.

20. A gas generator for an air bag according to claim 17 or 18, 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.

21. A gas generator for an air bag according to claim 1 or 2, wherein one of the two combustion chambers is provided on the outer side of the inner cylindrical member disposed in the housing, and an inner space of t he inner cylindrical member is defined into the other combustion chamber and an ignition means accommodating chamber by a partition wall.

22. A gas generator for an air bag according to claim 21, wherein the partition wall comprises a sectioning circular member engaged with a stepped notch portion provided on an inner peripheral surface of the inner cylindrical member and a seal cup member engaged with the sectioning circular member, a peripheral edge of the seal cup portion is bent, and the peripheral edge is fitted into a groove provided on the inner peripheral surface of the inner cylindrical member.

23. A gas generator for an air bag according to claim 22, wherein the ignition means includes an igniter to be activated by an electric signal, the igniter is supported to an igniter fixing member which covers the upper surface of the initiator collar so as to be fixed to 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 igniter, and the O-ring seals between the igniter fixing member and the igniter receiving port, between the igniter fixing member and the igniter, and between the igniter receiving port and the igniter.

24. A gas generator for an air bag according to any one of claims 1 to 23, wherein a cylindrical coolant means for purifying and/or cooling the combustion gas generated by the combustion of the gas generating means is disposed in the housing, and the combustion gas generated in the two combustion chambers passes through the same coolant means.

25. A gas generator for an air bag according to any one of claims 1 to 24, wherein the gas generating means stored in the two combustion chambers are burnt at different timings at the respective combustion chambers, and an automatic igniting material (AIM) to be ignited and burnt by transmission of heat generated by combustion of a previously burnt gas generating agent, is arranged in the combustion chamber where gas generating means to be burnt at a delayed timing is stored.

26. 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 25.

59. A gas generator for an air bag according to claim 6, wherein the partitioned circular member is engaged with a stepped notch portion provided on an inner peripheral surface of the inner cylindrical member.

3. A gas generator for an air bag, having an ignition means to be activated on an impact, and gas generating means which is to be ignited and burnt by the ignition means and generate a combustion gas for inflating an air bag in a housing with a plurality of gas discharge ports on a peripheral wall thereof which is formed into a cylindrical shape having an axial core length longer than an outermost diameter, wherein two combustion chambers storing the gas generating means are concentrically provided so as to be adjacent in the axial direction and/or the radial direction of the housing, and a communicating hole which allows communication between the combustion chambers is provided, in the housing.

4. A gas generator for an air bag according to claim 3, wherein, in the housing, a coolant means accommodating chamber which stores coolant means for purifying and cooling the combustion gas is further defined on the same axis as the two combustion chambers.

27. A gas generator for an air bag, having an ignition means to be activated on an impact, and gas generating means which is to be ignited and burnt by the ignition means and generate a combustion gas for inflating an air bag in a housing with a gas discharge port, wherein, in the housing, two or more combustion chambers storing the gas generating means are defined, the gas generating means stored in the respective combustion chambers are independently ignited and burnt by ignition means provided in the respective combustion chambers, and the gas generating means stored in the respective combustion chambers are different from each other in at least one of a burning rate, a shape, a composition, a composition ratio and an amount.

32. A gas generator for an air bag according to any one of claims 27 to 31, wherein the shape of the gas generating means different at each combustion chamber is a thickness or a surface area of the gas generating agent, and the amount of the gas generating means different at the respective combustion chambers is a weight.

33. A gas generator for an air bag according to any one of claims 27 to 32, wherein the plurality of combustion chambers are charged with the gas generating means to provide different burning rates from each other respectively, and with respect to a burning rate (Vs) in the gas generating means with a small burning rate stored in one combustion chamber, a value (V1/Vs) of a burning rate (V1) in the gas generating means with a large burning rate stored in the other combustion chambers is in a range between larger than 1 and smaller than 14.

34. A gas generator for an air bag according to any one of claims 27 to 33, wherein the plurality of combustion chambers are charged with the gas generating means to provide different shapes from each other respectively, the gas generating means stored in one combustion chambers and the gas generating means stored in the other combustion chambers are different in thickness and/or surface area thereof.

35. A gas generator for an air bag according to any one of claims 27 to 34, wherein a plurality of combustion chambers are charged with the gas generating means to provide different thickness from each other respectively, and with respect to a thickness (Ts) in the gas generating means with a small thickness stored in one combustion chamber, a value (T1/Ts) of a thickness (T1) of the gas generating means with a large thickness stored in the other combustion chambers is adjusted to a range between larger than 1 and 100 or less.

36. A gas generator for an air bag according to any one of claims 27 to 35, wherein a plurality of combustion chambers are charged with the gas generating means to provide different surface areas per a unit weight from each other, respectively, with respect to a surface area (Ss) of the gas generating means with a small surface area stored in one combustion chamber, a value (S1/Ss) of a surface area (S1) of the gas generating means with a large surface area stored in the other combustion chambers is in a range between larger than 1 and smaller than 50.

37. A gas generator for an air bag according to any one of claims 27 to 36, wherein the generator is constructed to be shorter in the axial direction than the radial direction, a plurality of combustion chambers are charged with the gas generating means to provide different shapes and/or amounts from each other, respectively, and a ratio (TS1:

TS2) of a total surface area (TS1) of the gas generating means stored in one combustion chamber to a total surface area (TS2) of the gas generating means stored in another combustion chamber is adjusted in a range between 1;

50 and 50;

1.

38. A gas generator for an air bag according to any one of claims 27 to 37, wherein the gas generator is constructed to be shorter in the axial direction than the radial direction, a plurality of combustion chambers are charged with the gas generating means to provide different shapes and/or amounts from each other, respectively, and a ratio (TS1:

TS2) of a total surface area (TS1) of the gas generating means stored in one combustion chamber to a total surface area (TS2) of the gas generating means stored in another combustion chamber is adjusted in a range between 1;

300 and 300;

1.

39. A gas generator for an air bag according to any one of claims 27 to 38, wherein the generator is constructed to be shorter in the axial direction than the radial direction, a plurality of combustion chambers are charged with the gas generating means to provide different weights from each other, respectively, and a ratio (TW1:

TW2) of a total weight (TW1) of the gas generating means stored in one combustion chamber to a total weight (TW2) of the gas generating means stored in another combustion chamber is adjusted in a range between 1;

50 and 50;

1.

40. A gas generator for an air bag according to any one of claims 27 to 39, wherein the gas generator is constructed to be shorter in the axial direction than the radial direction, a plurality of combustion chambers are charged with the gas generating means to provide different weights from each other, respectively, and a ratio (TW1:

TW2) of a total weight (TW1) of the gas generating means stored in one combustion chamber to a total weight (TW2) of the gas generating means stored in another combustion chamber is adjusted to a range between 1;

300 and 300;

1.

41. 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 27 to 40.

28. A gas generator for an air bag, having an ignition means to be activated on an impact, and gas generating means which is to be ignited and burnt by the ignition means and generate a combustion gas for inflating an air bag in a housing with a gas discharge port, 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, a communicating hole which allows communication between the combustion chambers is provided, and the gas generating means which are different from each other in at least one of a burning rate, a shape, a composition, a composition ratio and an amount is stored in the respective combustion chambers.

29. A gas generator for an air bag, having an ignition means to be activated on an impact, and gas generating means which is to be ignited and burnt by the ignition means and generate a combustion gas for inflating an air bag in a housing with a gas discharge port, wherein two or more combustion chambers storing the gas generating means are defined in the housing, the gas generating means stored in the respective combustion chambers are independently ignited and burnt by ignition means provided in the respective combustion chambers, and the gas generating means stored in the respective combustion chambers are different from each other in an amount of the generated gas per a unit time at the respective combustion chambers.

30. A gas generator for an air bag, having two or more ignition means to be activated on an impact, and gas generating means which is to be respectively ignited and burnt by the ignition means and generate a combustion gas for inflating an air bag in a housing forming an outer shell container, having a plurality of gas discharge ports thereon, wherein the gas discharge ports are closed by sealing means for maintaining an internal pressure of the housing to a predetermined pressure, a breaking pressure for breaking the sealing means is adjusted at multiple stages by controlling the gas discharge ports and/or the sealing means so as to suppress a difference of a maximum internal pressure of the housing when the respective ignition means are activated, gas generating means, which are different from each other in at least one of a burning rate, a shape, a composition, a composition ratio and an amount, are stored respectively in the two or more chambers defined in the housing, and the gas generating means in the respective combustion chambers can be independently ignited and burnt at an optional timing.

31. A gas generator for an air bag, having two or more ignition means to be activated on an impact, and gas generating means which is to be respectively ignited and burnt by the ignition means and generate a combustion gas for inflating an air bag in a housing forming an outer shell container, having a plurality of gas discharge ports thereon, wherein the gas discharge ports are closed by sealing means for maintaining an internal pressure of the housing to a predetermined pressure, a breaking pressure for breaking the sealing means is adjusted at multiple stages by controlling the gas discharge ports and/or the sealing means so as to suppress a difference of a maximum internal pressure of the housing when the respective ignition means are activated, and gas generating means, which are different from each other in at least one of a burning rate, a shape, a composition, a composition ratio and an amount, are charged in the respective combustion chambers.

42. A gas generator for an air bag having an ignition means to be activated on an impact, and gas generating means which is to be ignited and burnt by the ignition means and generate a combustion gas for inflating an air bag in a housing with a gas discharge port, wherein the ignition means includes two or more igniters to be activated on an impact and the igniters are provided so as to be aligned to each other in the axial direction.

43. A gas generator for an air bag according to claim 42, wherein two or more igniters contained in the ignition means are fitted in one initiator collar so as to be aligned to each other in the axial direction.

44. A gas generator for an air bag as stated in claim 42, wherein two or more igniters contained in the ignition means are integrated by resin so as to be aligned to each other in the axial direction.

45. A gas generator for an air bag as stated in claim 42, wherein two or more igniters contained in the ignition means are provided integrally by resin in one initiator collar so as to be aligned to each other in the axial direction.

48. A gas generator for an air bag according to claim 47, wherein two or more igniters contained in the ignition means are integrally provided by a resin in one initiator collar.

49. A gas generator for an air bag according to any one of claims 42 to 48, which has two or more ignition means, and two or more gas generating means which are to be independently ignited and burnt by the respective ignition means so as to generate combustion gas for inflating the air bag.

50. A gas generator for an air bag according to any one of claims 42 to 49, wherein 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.

51. A gas generator for an air bag according to any one of claims 42 to 50, wherein the ignition means comprises two or more igniters to be activated on an impact, and the respective igniters are different from each other in the operating output.

52. 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 42 to 51.

46. A gas generator for an air bag having an ignition means to be activated on an impact, and gas generating means which is to be ignited and burnt by the ignition means and generate a combustion gas for inflating an air bag in a housing with a gas discharge port, wherein the ignition means includes two or more igniters to be activated on an impact and the igniters are integrally provided by resin.

47. A gas generator for an air bag, having an ignition means to be activated on an impact, and gas generating means which is to be ignited and burnt by the ignition means and generate a combustion gas for inflating an air bag in a housing with a gas discharge port, wherein the ignition means includes two or more igniters to be activated on an impact, and the igniters are fitted into one initiator collar.

53. A gas generator for an air bag, having an ignition means to be activated on an impact, and gas generating means which is to be ignited and burnt by the ignition means and generate a combustion gas for inflating an air bag in a housing with a gas discharge port, wherein, in the housing, two or more combustion chambers storing the gas generating means are provided, a communicating hole which allows communication between the combustion chambers is provided, one of the two combustion chambers is provided in the upper space side of the inner cylindrical member disposed in the housing, the ignition means is provided in the lower space side of the inner cylindrical member, and the upper space and the lower space are defined by a partition wall.

56. A gas generator for an air bag a according to any one of claims 53 to 55, wherein the ignition means comprises two or more igniters to be activated on an impact, and each igniter is provided in an initiator collar and fixed by an igniter fixing member which covers the upper surface of the initiator collar.

58. A gas generator for an air bag according to any one of claims 53 to 57, wherein one of the two combustion chambers is provided outside the inner cylindrical member disposed in the housing, an inner space of the inner cylindrical member is partitioned into the other combustion chamber and an ignition means accommodating chamber in which the ignition means including the igniter is stored, by a partitioned circular member and a seal cup member engaged with the partitioned circular member.

61. A gas generator for an air bag according to any one of claims 53 to 60, wherein the igniter contained in the ignition means is supported to the igniter fixing member which covers the upper surface of the initiator collar and fixed to the initiator collar, the seal cup member has an igniter receiving port extending to the igniter fixing member, an O-ring is arranged in a space constituted by the igniter fixing member, the igniter receiving port and the igniter, and the O-ring seals between the igniter fixing member and the igniter receiving port, between the igniter fixing member and the igniter, and between the igniter receiving port and the igniter.

62. A gas generator for an air bag according to any one of claims 53 to 61, wherein an O-ring is interposed between the bent portion of the peripheral edge in the seal cup portion and the inner wall surface of the inner cylindrical member to which the bent portion is fitted.

63. 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 53 to 62.

54. A gas generator for an air bag, having an ignition means to be activated on an impact, and gas generating means which is to be ignited and burnt by the ignition means and generate a combustion gas for inflating an air bag in a housing with a gas discharge port, wherein, in the housing, two or more combustion chambers storing the gas generating means are concentrically provided so as to be adjacent in the radial direction of the housing, a communicating hole which allows communication between the combustion chambers is provided, an inner combustion chamber of the two combustion chambers is provided in the upper space side of the inner cylindrical member disposed in the housing, the ignition means is provided in the lower space side of the inner cylindrical member, and the upper space and the lower space are defined by a partition wall.

55. A gas generator for an air bag ignition means to be activated on an impact, and gas generating means which is to be ignited and burnt by the ignition means and generate a combustion gas for inflating an air bag in a housing formed into a cylindrical shape having an axial core length longer than an outermost diameter, and having a plurality of gas discharge ports on a peripheral wall thereof, wherein, in the housing, two combustion chambers storing the gas generating means are concentrically provided so as to be adjacent to each other in the axial direction and/or the radial direction of the housing, a communicating hole which allows communication between the combustion chambers is provided, an inner combustion chamber of the two combustion chambers is provided in the upper space side of an inner cylindrical member disposed in the housing, the ignition means is provided in the lower space side of the inner cylindrical member, and the upper space and the lower space are defined by a partition wall.

57. A gas generator for an air bag according to claim 56, wherein the two or more igniters are provided in one initiator collar.

60. A gas generator for an air bag according to claim 58 or 59, wherein a peripheral edge of the seal cup member is bent, and the bent portion of the peripheral edge is fitted into a groove provided on the inner peripheral surface of the inner cylindrical member.

64. A gas generator for an air bag having an ignition means to be activated on an impact and gas generating means which is to be ignited and burnt by the ignition means and generate a combustion gas for inflating an air bag in a housing with a gas discharge port, wherein, in the housing, two combustion chambers storing the gas generating means are provided, a communicating hole which allows communication between the combustion chambers is provided, the ignition means comprises two or more igniters activated by an electric signal, a lead wire for transmitting the electric signal is connected to each igniter, and the lead wire is drawn out in the same direction on the same plane.

65. A gas generator for an air bag according to claim 64, wherein the ignition means comprises two or more igniters to be activated by an electric signal, a lead wire for transmitting the electric signal is connected to each igniter via a connector, and the connectors are arranged in parallel on the same plane.

66. A gas generator for an air bag according to claim 64 or 65, wherein the ignition means comprises two or more igniters to be activated by an electric signal, a lead wire for transmitting the electric signal is connected to each igniter via a connector, and the lead wire is drawn out in the same direction perpendicular to the axial direction of the housing by the connector.

67. A gas generator for an air bag according to any one of claims 64 to 66, wherein the igniters are provided in one initiator collar so as to be aligned in the axial direction to each other, and each igniter is arranged eccentrically with respect to the center axis of the housing.

68. A gas generator for an air bag according to any one of claims 64 to 67, wherein two combustion chambers storing the gas generating means 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.

70. A gas generator for an air bag according to any one of claims 64 to 69, having an ignition means to be activated on an impact, and gas generating means which is to be ignited and burnt by the ignition means and generate a combustion gas for inflating an air bag in a housing formed into a cylindrical shape having an axial core length longer than an outermost diameter, and having a plurality of gas discharge ports on a peripheral wall thereof, wherein, in the housing, two combustion chambers storing the gas generating means are concentrically provided so as to be adjacent to each other in the axial direction and/or the radial direction of the housing, and a communicating hole which allows communication between the combustion chambers is provided.

69. A gas generator for an air bag, having an ignition means to be activated on an impact, and gas generating means which is to be ignited and burnt by the ignition means and generate a combustion gas for inflating an air bag in a housing with a gas discharge port, wherein, in the housing, two combustion chambers storing the gas generating means are provided, a communicating hole which allows communication between the combustion chambers is provided, the ignition means comprises two or more igniters to be activated by an electric signal, a lead wire for transmitting the electric signal is connected to each igniter, and the lead wire is disposed on the same plane and structured such that an angle at which a center line of the lead wire connected to one igniter and a center line of the lead wire connected to the other igniter cross to each other is 180 degrees or less.

71. A gas generator for an air bag, having an ignition means to be activated on an impact, and gas generating means which is to be ignited and burnt by the ignition means and generate a combustion gas for inflating an air bag in a housing with a gas discharge port, wherein two or more combustion chambers storing the gas generating means are sectioned and provided in the housing, a communicating hole which allows communication between the combustion chambers is provided, and an automatic ignition material (AIM) which is to be ignited and burnt by transmitted heat is arranged in one combustion chamber.

72. A gas generator for an air bag according to claim 71, wherein the gas generating means stored in the plurality of combustion chambers are burnt at different timing at each combustion chamber, the automatic ignition material (AIM) which is to be ignited and burnt by a transmission of the heat generated due to a combustion of the previously burnt gas generating agent is arranged in the combustion chamber where the gas generating means to be burnt at a delayed timing is stored.

73. A gas generator for an air bag according to claim 72, wherein the automatic ignition material ignites the gas generating agent which is to be burnt at 100 milliseconds or later than the timing when the ignition means for igniting the firstly burning gas generating means is activated.

74. A gas generator for an air bag according to claim 72 or 73, wherein the automatic ignition material is arranged so as to be combined with the igniter contained in the ignition means for igniting and burning the gas generating means to be burnt at a delayed timing.

75. A gas generator for an air bag according to any one of claims 71 to 74, wherein two combustion chambers storing the gas generating means are provided in the housing, and the gas generating means to be firstly burnt and the gas generating means to be burnt at a later timing are respectively provided in the respective combustion chambers as the first gas generating means the second gas generating means.

76. A gas generator for an air bag according to any one of claims 71 to 75, wherein, in the housing, two combustion chambers storing the gas generating means are concentrically provided in the housing so as to be adjacent to each other in the radial direction of the housing and a communication hole which allows communication between the combustion chambers is provided.

77. A gas generator for an air bag according to any one of claims 71 to 76, wherein the ignition means comprises a transfer charge to be ignited and burnt by 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 stored in the plurality of combustion chambers are respectively ignited and burnt by flames generated by combustion of the transfer charge in the respective sections.

78. 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 to 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 71 to 77.