Gas generator

• US 20050151357A1
• Filed: 12/15/2004
• Published: 07/14/2005
• Est. Priority Date: 12/19/2003
• Status: Active Grant

• Current Assignee: Daicel Chemical Industries Limited
• Original Assignee: Daicel Chemical Industries Limited
• Inventors: Yamazaki, Masayuki
• Granted Patent: US 7,806,435 B2
• Time in Patent Office: Days
• US Class Current: 280/741
• CPC Class Codes: B60R 2021/26011 using a filter through which the inflation gas passes
• CPC Class Codes: B60R 21/2644 using only solid reacting substances, e.g. pellets, powder

Abstract

To provide a gas generator with improved filter function.

A housing 11 has an upper annular inclined surface 14 and a lower annular inclined surface 15. An annular filter 20 accommodated inside the housing has the end surface shape matching that of the inclined surfaces 14, 15. When the housing expands and deforms in the axial direction by the pressure during actuation, the inclined surfaces 14, 15 cannot be easily deformed. Therefore, the gas is prevented from leaking from the abutment portion of the inclined surfaces 14, 15 and cylindrical filter 20. As a result, the entire gas is discharged via the annular filter 20.

Claims

1. A gas generator comprising a housing composed of a peripheral wall portion having a gas discharge port, a top plate, and a bottom plate, ignition means accommodated inside the housing, a gas generating agent which is ignited and burned with the ignition means, and an annular filter disposed so as to surround the ignition means and gas generating agent, wherein

a surface including the annular contact portion of the peripheral wall portion and the top plate is formed as an upper annular inclined surface, and a surface including the annular contact portion of the peripheral wall portion and the bottom plate is formed as a lower annular inclined surface;

and

the annular filter is so disposed that both end surfaces thereof abut against the upper annular inclined surface and lower annular inclined surface and a gap is provided between the annular filter and the peripheral wall portion.

2. The gas generator according to claim 1, wherein the angle formed by the top plate and the upper annular inclined surface and the angle formed by the bottom plate and the lower annular inclined surface are equal or close to the angle formed by the top plate in the state thereof before the expansion and the top plate in the state thereof after the expansion and the angle formed by the bottom plate in the state thereof before the expansion and the bottom plate in the state thereof after the expansion during expansion and deformation taking place when neither the upper annular inclined surface nor the lower annular inclined surface is present.

3. The gas generator according to claim 1 or 2, wherein both end surfaces of the annular filter and the upper and lower annular inclined surfaces are pressed against each other in the axial direction of the housing.

4. The gas generator according to claim 1, wherein

a tubular member with the inner space thereof serving as a first combustion chamber is disposed inside the housing, this tubular member having a tubular main portion and an annular plane extending in the radial direction of the housing from the edge of the open portion at one end of the main portion;

the tubular member is disposed concentrically with the housing, the annular plane abuts against the top plate, and ignition means is accommodated and fixed in the open portion at the other end; and

the outer peripheral edge of the annular plane abuts against the inner peripheral surface of the annular filter and covers from the inside the contact portion of the top plate and both end surfaces of the annular filter.

5. The gas generator according to claim 4, wherein the top plate has a recessed portion in the central part, and said recessed portion is located inside the open portion at one end side of the tubular member.

6. An air bag apparatus using the gas generator according to claim 1 or 2.