Pressurized medium for inflator

• US 20030085559A1
• Filed: 09/24/2002
• Published: 05/08/2003
• Est. Priority Date: 09/27/2001
• Status: Active Grant

• Current Assignee: Daicel Chemical Industries Limited (Daicel Corporation)
• Original Assignee: Daicel Chemical Industries Limited (Daicel Corporation)
• Inventors: Nakayasu, Masayuki, Iwai, Yasunori, Goto, Yuzo
• Granted Patent: US 6,883,830 B2
• Time in Patent Office: Days
• US Class Current: 280/741
• CPC Class Codes: B60R 2021/0018 Roll-over
• CPC Class Codes: B60R 21/268 using instantaneous release of stored pressurised gas B60R21/26005 takes precedence

Abstract

The present invention provides an inflator capable of prolonging the duration of inflation of an air bag.

Since an inflator housing 12 of an inflator 10 for a curtain air bag is charged with a pressurized medium comprising a mixed gas of He and Ar (He:Ar=3:7 to 7:3), the sound velocity of the pressurized medium is smaller than that of a pressurized medium comprising He only, and the viscosity of the former is higher than that of the latter, so that the duration of the inflation of an air bag can be prolonged.

Claims

1. A pressurized medium for an inflator charged in an inflator of a type in which a body to be inflated is mainly inflated with a pressurized medium, wherein the pressurized medium comprises helium and argon and the mixing ratio thereof is in the range of helium:

argon=3;

7 to 7;

3 by molar ratio.

2. A pressurized medium for an inflator according to claim 1, whose sound velocity is 400 to 800 m/s at 23°

C.

3. A pressurized medium for an inflator according to claim 1 or 2, whose coefficient of viscosity is 25 to 40 μ

Pa·

s at 50 MPa and at 300°

K.

4. A pressurized medium for an inflator according to any one of claims 1 to 3, wherein, when a tank test is conducted such that, after an inflator charged with a pressurized medium under pressure of 50,000 kPa and having 33 mm² of a total opening area of a gas discharging port is inserted into a tank having a single hole with a diameter of 6 mm and an inner volume of 28.3 liters, the inflator is activated to discharge the pressurized medium to measure a pressure change inside a tank, the pressure reduction rate of a tank internal pressure at 0.5 seconds after the activation of the inflator becomes not more than 25%.

5. A pressurized medium for an inflator according to claim 4, wherein the tank internal pressure does not become 0 kPa until four seconds elapse from activation of the inflator.

6. An inflator which is charged with a pressurized medium for an inflator according to any one of claims 1 to 5 as a means for inflating the body to be inflated.

7. An inflator which comprising an inflator housing which is charged with a pressurized medium and has an opening portion at one end, and a diffuser portion which is fixed to the opening portion side of the inflator housing and is provided with a gas discharging port for discharging, to the outside, a pressurized medium flowing from the opening portion at a time of activation, a rupturable plate closing the flow passage of the pressurized medium between the opening portion of the inflator housing and diffuser portion, and a rupturable means for rupturing the rupturable plate, wherein the pressurized medium for an inflator according to any one of claims 1 to 5 is used as a pressurized medium.

8. An air bag apparatus comprising an activation signal-outputting means including an impact sensor and a control unit, and a module case accommodating an inflator according to claim 6 or 7 and an air bag.