SMALL GAS-GENERATING DEVICE FOR GAS ACTUATOR AND PRETENSIONER SYSTEM

• US 20100186615A1
• Filed: 01/17/2007
• Published: 07/29/2010
• Est. Priority Date: 01/18/2006
• Status: Active Grant

• Current Assignee: Nippon Kayaku Company Limited
• Original Assignee: Nippon Kayaku Company Limited
• Inventors: Sato, Eishi, Yoshida, Hirokazu, Kodama, Ryoi
• Granted Patent: US 8,176,851 B2
• Time in Patent Office: Days
• US Class Current: 102/530
• CPC Class Codes: B60R 21/2644 using only solid reacting substances, e.g. pellets, powder
• CPC Class Codes: B60R 22/4628 characterised by fluid actuators, e.g. pyrotechnic gas generators actuating a cable B60R22/4619
• CPC Class Codes: C06B 45/00 Compositions or products which are defined by structure or arrangement of component of product explosive charges of particular form or shape F42B1/00, F42B3/00
• CPC Class Codes: C06D 5/06 by reaction of two or more solids
• CPC Class Codes: F42B 3/04 for producing gas under pressure generators of inflation fluid especially adapted for vehicle air bags B60R21/26
• CPC Class Codes: F42B 3/103 Mounting initiator heads in initiators; Sealing-plugs

Abstract

A gas generator including a cup filled with gas generant molded articles that generate gas by combustion, and an ignitor on which an ignition agent is disposed. Each gas generant molded article is formed of smokeless powders containing nitrocellulose as its major ingredient. Each gas generant molded article includes an explosive containing a fuel agent containing a guanidine derivative and/or a tetrazole derivative and an oxidizing agent containing a metal nitrate and/or perchlorate. Thus, it is possible to provide a gas generator by which the amount of CO gas generated in operation can be reduced and the combustion speed can easily be controlled, and to provide a pretensioner system provided with the gas generator.

Claims

1. A small gas generator, having a combustion chamber for generating gas, for a gas actuator for operating a safety device,

the generator comprising, in the combustion chamber, first gas generant molded articles containing a fuel component including a guanidine derivative and/or a tetrazole derivative, and an oxidizing agent component containing a metal nitrate and/or a perchlorate;

and second gas generant molded articles containing smokeless powders including nitrocellulose as a major ingredient.

2. The small gas generator according to claim 1, wherein the metal nitrate is a salt of a metal selected out of alkali metals and alkali earth metals, and the perchlorate contains ammonium perchlorate or potassium perchlorate.

3. The small gas generator according to claim 1, wherein the fuel agent contains one or more selected out of nitroguanidine, guanidine nitrate, bitetrazole, azobistetrazole, and 5-aminotetrazole, and the oxidizing agent is a mixture of ammonium perchlorate and strontium nitrate, or potassium perchlorate, and further contains a binder.

4. The small gas generator according to claim 3, wherein the binder contains a mixture of hydroxypropylmethylcellulose and polyacrylamide.

5. The small gas generator according to claim 4, wherein each first gas generant molded article further contains an additive, and the content of the fuel agent is 20 to 55% by weight;

the content of the oxidizing agent is 40 to 70% by weight;

the content of the binder is 2 to 10% by weight; and

the content of the additive is 2 to 10% by weight, which are controlled so that the total of the fuel agent, the oxidizing agent, the binder, and the additive is 100% by weight.

6. The small gas generator according to claim 1, wherein the ratio Av/Bv between the volume Av of one first gas generant molded article and the volume Bv of one second gas generant molded article is 1.2 to 1.5.

7. The small gas generator according to claim 1, wherein the ratio Aw/Bw between the whole weight Aw of the first gas generant molded articles and the whole weight Bw of the second gas generant molded articles is 0.5 to 2.0.

8. The small gas generator according to claim 1, wherein the ratio (dPA/dt)/(dPB/dt) between the combustion speed dPA/dt of the first gas generant molded articles and the combustion speed dPB/dt of the second gas generant molded articles is 0.3 to 1.5.

9. The small gas generator according to claim 1, wherein the ratio (dPA/dt)/(dPB/dt) between the combustion speed dPA/dt of the first gas generant molded articles and the combustion speed dPB/dt of the second gas generant molded articles is 0.5 to 1.0.

10. A pretensioner system comprising the small gas generator according to claim 1.

11. The small gas generator according to claim 2, wherein the fuel agent contains one or more selected out of nitroguanidine, guanidine nitrate, bitetrazole, azobistetrazole, and 5-aminotetrazole, and the oxidizing agent is a mixture of ammonium perchlorate and strontium nitrate, or potassium perchlorate, and further contains a binder.

12. The small gas generator according to claim 11, wherein the binder contains a mixture of hydroxypropylmethylcellulose and polyacrylamide.

13. The small gas generator according to claim 12, wherein each first gas generant molded article further contains an additive, and the content of the fuel agent is 20 to 55% by weight;

the content of the oxidizing agent is 40 to 70% by weight;

the content of the binder is 2 to 10% by weight; and

the content of the additive is 2 to 10% by weight, which are controlled so that the total of the fuel agent, the oxidizing agent, the binder, and the additive is 100% by weight.

14. The small gas generator according to claim 2, wherein the ratio Av/Bv between the volume Av of one first gas generant molded article and the volume Bv of one second gas generant molded article is 1.2 to 1.5.

15. The small gas generator according to claim 2, wherein the ratio Aw/Bw between the whole weight Aw of the first gas generant molded articles and the whole weight Bw of the second gas generant molded articles is 0.5 to 2.0.

16. The small gas generator according to claim 2, wherein the ratio (dPA/dt)/(dPB/dt) between the combustion speed dPA/dt of the first gas generant molded articles and the combustion speed dPB/dt of the second gas generant molded articles is 0.3 to 1.5.

17. The small gas generator according to claim 2, wherein the ratio (dPA/dt)/(dPB/dt) between the combustion speed dPA/dt of the first gas generant molded articles and the combustion speed dPB/dt of the second gas generant molded articles is 0.5 to 1.0.

18. A pretensioner system comprising the small gas generator according to claim 2.