Inflator for air bag

• US 20040130134A1
• Filed: 10/28/2003
• Published: 07/08/2004
• Est. Priority Date: 10/29/2002
• Status: Active Grant

• Current Assignee: Daicel Chemical Industries Limited
• Original Assignee: Daicel Chemical Industries Limited
• Inventors: Nakayasu, Masayuki, Katsuda, Nobuyuki
• Granted Patent: US 7,052,037 B2
• Time in Patent Office: Days
• US Class Current: 280/737
• CPC Class Codes: B60R 2021/2612 Gas guiding means, e.g. ducts
• CPC Class Codes: B60R 21/232 Curtain-type airbags deploying mainly in a vertical direction from their top edge
• CPC Class Codes: B60R 21/268 using instantaneous release of stored pressurised gas B60R21/26005 takes precedence

Abstract

The present invention provides an inflator for an air bag in which fragments of a rupturable plate do not flow into the air bag, a stable operational performance is exhibited, a manufacturing cost is reduced but durability is improved and installation is made easy.

The present invention provides an inflator for an air bag comprising a diffuser portion having a gas discharging port and a gas discharging duct extending from the gas discharging port in the axial direction of an inflator housing, wherein the total opening area of plural openings provided at distal ends of a branched portion in the gas discharging duct is larger than the opening area of an orifice portion provided inside the diffuser portion.

Claims

1. An inflator for an air bag comprising:

a cylindrical inflator housing charged a pressurized medium inside and formed with an opening portion at the axial end portion;

a diffuser portion installed at the opening portion of the inflator housing, provided with a gas discharging port and having an inner space extending from the opening portion to the gas discharging port as a gas flow passage;

a rupturable plate provided in the gas flow passage inside the diffuser portion to seal outflow of a pressurized medium;

an ignition means accommodated inside the diffuser portion and rupturing the rupturable plate by activation; and

a gas discharging duct extending from the gas discharging port and having a distal end branched in opposite two directions, wherein

an orifice portion for regulating a gas flow amount is formed in the gas flow passage inside the diffuser portion while distal ends of the branched portions in the gas discharging duct are formed with plural openings, and

the plural openings provided at the distal end of the branched portion in the gas discharging duct are formed such that the total opening area thereof is larger than the opening area of the orifice portion.

2. An inflator for an air bag according to claim 1, wherein the total opening area of the plural openings provided at one of the distal ends of the branched portion in the gas discharging duct is different from the total opening area of the plural openings provided at the other distal end of the branched portion.

3. An inflator for an air bag according to claim 1 or 2, wherein the inflator housing has a cylindrical shape elongated axially rather than radially, and the branched portion of the gas discharging duct is formed in a substantially “

T”

-letter shape.

4. An inflator for an air bag according to any one of claims 1 to 3, wherein the inflator housing has a cylindrical shape elongated axially rather than radially, and the gas discharging duct extends in an axial direction of the inflator housing to then turn at one or at least two portions and the branched portion formed in the substantially “

T”

-letter shape is provided ahead thereof.

5. An inflator for an air bag according to any one of claims 1 to 4, wherein the rupturable plate is formed in a disk shape, and each opening of the plural openings provided at the distal ends of the branched portion in the gas discharging duct is formed to have a diameter smaller than a radius of the rupturable plate.

6. An inflator for an air bag according to any one of claims 1 to 5, wherein end surfaces of the distal ends of the branched portion in the gas discharging duct are closed and the openings are formed on peripheries of the distal ends of the branched portion.

7. An inflator for an air bag according to any one of claims 1 to 6, wherein the ignition means includes an igniter receiving an electric signal to be activated, and the igniter is arranged inside the diffuser portion to cross the axis of the inflator housing.