Inflator

• US 20030098572A1
• Filed: 01/03/2003
• Published: 05/29/2003
• Est. Priority Date: 08/29/2000
• Status: Active Grant

• Current Assignee: Daicel Chemical Industries Limited (Daicel Corporation)
• Original Assignee: Daicel Chemical Industries Limited (Daicel Corporation)
• Inventors: Matsuda, Naoki, Nakayasu, Masayuki, Katsuda, Nobuyuki
• Granted Patent: US 7,252,303 B2
• Time in Patent Office: Days
• US Class Current: 280/741
• CPC Class Codes: B21D 41/045 Closing
• CPC Class Codes: B60R 2021/0018 Roll-over
• CPC Class Codes: B60R 21/232 Curtain-type airbags deploying mainly in a vertical direction from their top edge
• CPC Class Codes: B60R 21/272 with means for increasing the pressure of the gas just before or during liberation, e.g. hybrid inflators

Abstract

The present invention provides an inflator which is reduced in size and weight without deteriorating its performance. CO₂ is charged into a housing of the inflator. Since the CO₂ can increase the charging density, the size of the housing 12 can be reduced accordingly. A combustion means is also used, and therefore, a maximum pressure at the time of actuation of the inflator is not lowered. Further, the present invention also provides an inflator capable of inflating a curtain air bag without being affected by variation in an ambient temperature. The pressurized medium comprising an inert gas having a sound velocity of not less than 400 m/sec is charged into the inflator housing. Therefore, it is possible to inflate the curtain air bag instantaneously even in the atmosphere having a temperature lower than the normal. Further, in a curtain air bag inflator that can be easily produced, one pipe whose one end is closed is used as the inflator housing. Therefore, the producing steps can be simplified as compared with a case using one plate material.

Claims

1. An inflator comprising a pressurized medium including carbon dioxide charged into a housing, a combustion means for heating the pressurized medium and an ignition means for burning the combustion means.

2. An inflator according to claim 1, wherein the content of the carbon dioxide in the pressurized medium is not less than 20 mol %.

3. An inflator according to claim 1 or 2, wherein the pressurized medium is a mixture of carbon dioxide and a different gas, and the different gas is at least one gas selected from the group consisting of an inert gas and nitrogen gas.

4. An inflator according to claim 1 or 2, wherein the pressurized medium is a mixture of carbon dioxide and a different gas, and the different gas is dinitrogen monoxide.

5. An inflator according to any one of claims 1 to 4, wherein the pressurized medium further comprises oxygen gas.

6. An inflator according to any one of claims 1 to 5, wherein a charging pressure of the pressurized medium is not less than 4 MPa.

7. An inflator comprising an inflator housing in which a pressurized medium is charged and an opening is provided at one end, and a diffuser portion which is fixed to the opening side of the inflator housing and is provided with a gas discharging port for discharging the pressurized medium flowing out of the opening at the time of actuation of the inflator, wherein an flow-path of the pressurized medium between the opening of the inflator housing and the diffuser portion is closed with a rupturable plate, and further a rupturing means for the rupturable plate is provided, and one selected among the following requirements (a), (b) and (c) is provided:

(a);

the pressurized medium filled in the inflator housing has a sound velocity of not less than 400 m/sec at 0°

C. at 1013.25 hPa;

(b);

a charging pressure at 20°

C. of the pressurized medium in the inflator housing is not less than 40,000 kPa; and

(c);

the total area (A₁) of the gas discharging port(s) and the area (A₂) of the opening is set to meet A₁/A₂≦

1.

10. An inflator according to any one of claims 7 to 9, wherein the pressurized medium meeting the requirement (a) has a sound velocity of not less than 900 m/sec at 0°

C. at 1013.25 hPa.

11. An inflator according to any one of claims 7 to 10, wherein the pressurized medium meeting the requirement (a) is one or a mixture of at least two selected only from an inert gas.

12. An inflator according to any one of claims 7 to 11, wherein the pressurized medium meeting the requirement (a) is helium and/or neon.

13. An inflator according to any one of claims 7 to 12, wherein a combustion means for heating the pressurized medium is not provided.

14. An inflator according to any one of claims 7 to 13, wherein the requirement (c) is A₁/A₂≦

0.95.

17. An inflator according to any one of claims 7 to 16, wherein the rupturing means for the rupturable plate is provided with the diffuser portion.

18. An inflator according to any one of claims 7 to 17, wherein the diffuser portion has a filter, the pressurized medium is discharged out of the gas discharging port through the filter.

19. An inflator according to any one of claims 7 to 18, wherein the inflator housing is a pipe closed at one end and connected at the other end to the diffuser portion.

20. An inflator according to any one of claims 7 to 19, wherein the rupturable plate is mounted to the opening side of the inflator housing or the diffuser portion side.

8. An inflator comprising an inflator housing in which a pressurized medium is charged and an opening is provided at one end, and a diffuser portion which is fixed to the opening of the inflator housing and is provided with a gas discharging port for discharging the pressurized medium flowing out of the opening at the time of actuation of the inflator, wherein an flow-path of the pressurized medium between the opening of the inflator housing and the diffuser portion is closed with a rupturable plate, and further a rupturing means for the rupturable plate is provided, and the following requirements (a) and (b), or (b) and (c), or (a) and (c) are provided:

(a);

the pressurized medium filled in the inflator housing has a sound velocity of not less than 400 m/sec at 0°

C. at 1013.25 hPa;

(b);

a charging pressure at 20°

C. of the pressurized medium in the inflator housing is not less than 40,000 kPa; and

(c);

the total area (A₁) of the gas discharging port(s) and the area (A₂) of the opening is set to meet A₁/A₂≦

1.

9. An inflator comprising an inflator housing in which a pressurized medium is charged and an opening is provided at one end, and a diffuser portion which is fixed to the opening of the inflator housing and is provided with a gas discharging port for discharging the pressurized medium flowing out of the opening at the time of actuation of the inflator, wherein an flow-path of the pressurized medium between the opening of the inflator housing and the diffuser portion is closed with a rupturable plate, and further a rupturing means for the rupturable plate is provided, and all of the following requirements (a), (b) and (c) are provided:

(a);

the pressurized medium filled in the inflator housing has a sound velocity of not less than 400 m/sec at 0°

C. at 1013.25 hPa;

(b);

a charging pressure at 20°

C. of the pressurized medium in the inflator housing is not less than 40,000 kPa; and

(c);

the total area (A₁) of the gas discharging port(s) and the area (A₂) of the opening is set to meet A₁/A₂≦

1.

15. An inflator comprising an inflator housing in which a pressurized medium is charged and an opening is provided at one end, and a diffuser portion which is fixed to the opening of the inflator housing and is provided with a gas discharging port for discharging the pressurized medium flowing out of the opening at the time of actuation of the inflator, wherein an flow-path of the pressurized medium between the opening of the inflator housing and the diffuser portion is closed with a rupturable plate, and further a rupturing means for the rupturable plate is provided, a gas discharging port is open, and the inside of the diffuser portion is under the normal pressure.

16. An inflator according to claim 15, further provided with one or two or three requirements selected among the following requirements (a), (b) and (c):

(a);

the pressurized medium filled in the inflator housing has a sound velocity of not less than 400 m/sec at 0°

C. at 1013.25 hPa;

(b);

a charging pressure at 20°

C. of the pressurized medium in the inflator housing is not less than 40,000 kPa; and

(c);

the total area (A₁) of gas charging port and the area (A₂) of the opening is set to meet A₁/A₂≦

1.

21. An inflator comprising an inflator housing in which a pressurized medium is charged and an opening is provided at one end, and a diffuser portion which is fixed to the opening of the inflator housing and is provided with a gas discharging port for discharging the pressurized medium flowing out of the opening at the time of actuation of the inflator, wherein an flow-path of the pressurized medium between the opening of the inflator housing and the diffuser portion is closed with a rupturable plate, and further a rupturing means for the rupturable plate is provided, and one end of a pipe of the inflator housing is closed, and the diffuser portion is connected to the other end of the inflator housing.

22. An inflator according to claim 21, wherein the pipe used for producing the inflator housing is uniform in diameter over the entire length in the longitudinal direction.

23. An inflator according to claim 21 or 22, wherein the inflator housing is obtained by forming the pipe in accordance with a swaging method.

24. An inflator according to claim 21 or 22, wherein the inflator housing is obtained by forming the pipe in accordance with a spinning orking method.

25. An inflator according to any one of claims 21 to 24, wherein the pressurized medium is charged from the closed end side of the inflator housing.

26. An inflator according to any one of claims 21 to 25, wherein the rupturable plate is mounted to the opening side of the inflator housing or the diffuser portion side.

27. A method for producing an inflator, which is a method for producing the inflator according to any one of claims 21, 22, 25 and 26, comprising the steps such that the thin hole is left at the time of closing one end of the pipe, and the thin hole is closed after the pressurized medium is charged from the thin hole.

28. A producing method of an inflator according to claim 27, comprising the steps such that the pipe is formed in accordance with a swaging method, a seal pin is fitted into the thin hole and the pressurized medium is charged, the portion where the seal pin is fitted is welded and closed.

29. A producing method of an inflator according to claim 27, comprising the steps such that the pipe is formed in accordance with a spinning method, a seal pin is fitted into the thin hole and the pressurized medium is charged, the portion where the seal pin is fitted is welded and closed.