Hybrid inflator

• US 20030001370A1
• Filed: 08/22/2002
• Published: 01/02/2003
• Est. Priority Date: 03/28/2000
• Status: Active Grant

• Current Assignee: Daicel Chemical Industries Limited (Daicel Corporation)
• Original Assignee: Daicel Chemical Industries Limited (Daicel Corporation)
• Inventors: Ogawa, Akihisa, Ryobo, Eiichi
• Granted Patent: US 7,059,635 B2
• Time in Patent Office: Days
• US Class Current: 280/741
• CPC Class Codes: B60R 2021/2633 with a plurality of inflation levels
• CPC Class Codes: B60R 21/272 with means for increasing the pressure of the gas just before or during liberation, e.g. hybrid inflators
• CPC Class Codes: C06D 5/06 by reaction of two or more solids

Abstract

The present invention provides a hybrid inflator in which a weight thereof and the number of manufacturing steps can be reduced. First and second communication holes 125 and 135 by which first and second gas generating chambers 120 and 130 communicates with an inflator housing 102 are formed in a gas generator housing 105. Therefore, no screen is required and thus, the weight and the number of manufacturing steps can be reduced.

Claims

1. A hybrid inflator for an inflating-type safety system of a vehicle provided with an air bag, which comprises an inflator housing, a gas generator provided in said inflator housing, and an ignition means chamber having an ignition means connected to said gas generator, wherein

the interior of said inflator housing is filled with a pressurized medium containing an inert gas;

said gas generator has an outer shell formed by a gas generator housing having a plurality of the communication holes;

said gas generator housing includes a gas generating chamber in which a gas generating agent is accommodated;

said gas generating chamber and said inflator housing are in communication with each other through said communication holes; and

each of said communication holes provided in said gas generator housing has such a size that a combustion gas generated in said gas generating chamber can flow out therethrough but the gas generating agent can be prevented from leaking outwards.

4. A hybrid inflator as claimed in any one of claims 1 to 3, wherein a plurality of the communication holes or a plurality of the first and/or second communication holes provided in said gas generator housing are not covered with a screen.

5. A hybrid inflator as claimed in any one of claims 1 to 4, wherein said gas generating agent is in contact with a plurality of the communication holes or a plurality of the first and second communication holes provided in said gas generator housing.

6. A hybrid inflator as claimed in any one of claims 1 to 5, wherein a plurality of the communication holes or a plurality of the first and second communication holes provided in said gas generator housing have the same hole diameters.

7. A hybrid inflator as claimed in any one of claims 1 to 6, wherein a plurality of the communication holes or a plurality of the first and second communication holes provided in said gas generator housing have hole diameters in a range of 0.5 to 3 mm.

8. A hybrid inflator as claimed in any one of claims 1 to 7, wherein the total number of a plurality of the communication holes or a plurality of the first and second communication holes provided in said gas generator housing is 100 to 600.

10. A hybrid inflator as claimed in any one of claims 1 to 9, wherein the total open area of a plurality of the communication holes or a plurality of the first and second communication holes provided in said gas generator housing is 100 to 600 mm².

11. A hybrid inflator as claimed in any one of claims 1 to 10, wherein a plurality of the communication holes or a plurality of the first and second communication holes provided in said gas generator housing are disposed in a plurality of lines in the longitudinal direction of said gas generator housing as well as in a plurality of the lines in the circumferential direction.

12. A hybrid inflator as claimed in any one of claims 2 to 10, wherein a portion or all of a plurality of the first and second communication holes provided in said gas generator housing are formed in different directions in the widthwise direction of said inflator housing.

20. A hybrid inflator as claimed in any one of claims 1 to 19 which is provided with one or two or three requirements selected among the requirements (1) to (3) described below:

(2) A molar ratio between an amount (A mol) of the pressurized medium and an amount (B mol) of a gas generated due to combustion of the gas generating agent is 8/2 to 1/9.

(2) A weight ratio (X/Y) of the weight (X) of the pressurized medium to the weight (Y) of the gas generating agent is 0.1 to 7.

(3) A pressure index determined by the following formula;

rb=α

Pⁿ (wherein, rb;

burning rate, a;

coefficient, P;

pressure, n;

pressure index), at the combustion of the gas generating agent, is smaller than 0.8.

21. An air bag system comprising an activation-signal outputting means including an impact sensor and a control unit, and a module case in which a hybrid inflator as claimed in any one of claims 1 to 20 and an air bag are accommodated.

2. A hybrid inflator for an inflating-type safety system of a vehicle provided with an air bag, which comprises an inflator housing, a gas generator provided in said inflator housing, and an ignition means chamber having an ignition means connected to said gas generator, wherein

the interior of said inflator housing is filled with a pressurized medium containing an inert gas;

said gas generator has an outer shell formed by a gas generator housing having a plurality of the first and second communication holes;

said gas generator housing includes, therein, first and second gas generating chambers each having a gas generating agent;

said first gas generating chamber and said inflator housing are in communication with each other through said first communication holes;

said second gas generating chamber and said inflator housing are in communication with each other through said second communication holes; and

each of said first and/or second communication holes has such a size that combustion gas generated in said first and/or second gas generating chamber can flow out therethrough but the gas generating agent can be prevented from leaking outwards.

9. A hybrid inflator as claimed in claim 2 or 8, wherein, in a plurality of the first and second communication holes provided in said gas generator housing, the total number of said first communication holes is 50 to 300, and the total number of said second communication holes is 50 to 300.

3. A hybrid inflator for an inflating-type safety system of a vehicle provided with an air bag, which comprises an inflator housing, a gas generator provided in said inflator housing, and an ignition means chamber having an ignition means connected to said gas generator, wherein

the interior of said inflator housing is filled with a pressurized medium containing an inert gas;

said gas generator has an outer shell formed by a gas generator housing having a plurality of the first and second communication holes;

said gas generator housing includes, therein, first and second gas generating chambers each having a gas generating agent;

a first ignition means chamber having a first ignition means is connected to a first gas generating chamber;

a second ignition means chamber having a second ignition means is connected to a second gas generating chamber;

said first gas generating chamber and said inflator housing are in communication with each other through said first communication holes;

said second gas generating chamber and said inflator housing are in communication with each other through said second communication holes; and

each of said first and/or second communication holes has such a size that combustion gas generated in said first and/or second gas generating chamber can flow out therethrough but the gas generating agent can be prevented from leaking outwards, said second communication holes are disposed at a distance from said second ignition means in the widthwise direction and/or the longitudinal direction of said inflator housing.

13. A hybrid inflator as claimed in claim 3, wherein, in a plurality of the first and second communication holes provided in said gas generator housing, a plurality of the first communication holes provided in said gas generator housing are disposed in a plurality of the lines in the longitudinal direction of said gas generator housing as well as on the entire surface in the circumferential direction, and a plurality of the second communication holes provided in said gas generator housing are disposed in a plurality of the lines in the longitudinal direction of said gas generator housing as well as on a half or less of the surface in the circumferential direction.

14. A hybrid inflator as claimed in claim 3 or 13, wherein said gas generator further includes a flame transferring means chamber, said flame transferring means chamber is disposed in extension in the longitudinal direction of said first ignition means chamber and is in communication with said first gas generating chamber, said second ignition means connected to said second gas generating chamber is disposed eccentrically with respect to the center axis of said inflator housing in the longitudinal direction.

15. A hybrid inflator as claimed in any one of claims 3, 13 and 14, wherein said first and second ignition means chambers are disposed adjacent to each other as well as in parallel in the widthwise direction of said inflator housing, said first ignition means chamber is disposed on the center axis in the longitudinal direction of said inflator housing.

16. A hybrid inflator as claimed in claim 2 or 15, wherein said first and second gas generating chambers have independent inflow paths for gases generated therein towards said inflator housing.

17. A hybrid inflator as claimed in claim 2 or 16, wherein said first and second gas generating chambers are disposed adjacent to each other in series in the longitudinal direction of said inflator housing.

18. A hybrid inflator as claimed in claim 2 or 16, wherein said first and second gas generating chambers are disposed to face each other in series in the longitudinal direction of said inflator housing.

19. A hybrid inflator as claimed in claim 2 or 16, wherein said first and second gas generating chambers are disposed in parallel, adjacent to each other or at a distance from each other in the widthwise direction of said inflator housing.