Gas generator

• US 7,806,435 B2
• Filed: 12/15/2004
• Issued: 10/05/2010
• Est. Priority Date: 12/19/2003
• Status: Active Grant

• Current Assignee: Daicel Chemical Industries Limited (Daicel Corporation)
• Original Assignee: Daicel Chemical Industries Limited (Daicel Corporation)
• Inventors: Yamazaki, Masayuki
• Primary Examiner(s): Dickson; Paul N.
• Assistant Examiner(s): Sliteris; Joselynn Y.
• Application Number:
  US11/011,032
• Publication Number:
  US 20050151357A1
• Time in Patent Office: 2,120 Days
• Field of Search: 280/741
• 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

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 annular 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, the top plate and the bottom plate bulging outwardly upon activation of the gas generator;

a collar directly attached to the bottom plate;

ignition means supported by the collar and accommodated inside the housing;

a tubular member including an upper end and a lower end and provided concentrically with respect to and within the housing such that the lower end is in engagement with the collar and the tubular member defines, in an inner side and an outer side thereof, a first combustion chamber, accommodating a first gas generating agent, and a second combustion chamber, accommodating a second gas generating agent, respectively, the tubular member being provided with a reduced-diameter portion forming a step in the upper end, and a main portion having a diameter larger than the reduced-diameter portion, a plurality of communication holes for communicating the first combustion chamber with the second combustion chamber being provided only in the main portion;

an annular plane extending in a radial direction of the housing from the upper end of the tubular member and including, in an inner side thereof, a bent portion, and being provided such that the bent portion abuts against the step; and

an annular filter disposed so as to surround the tubular member, wherein

the housing is provided with an upper annular inclined surface formed between the peripheral wall portion and the top plate, and a lower annular inclined surface formed between the peripheral wall portion and the bottom plate, a first angle of the upper annular inclined surface with respect to an imaginary line extending perpendicular to an axial direction of the housing and a second angle of the lower annular inclined surface with respect to the imaginary line do not substantially change before and after the activation of the gas generator, and

the annular filter is disposed such that an upper end surface and a lower end surface thereof abut against the upper annular inclined surface and the lower annular inclined surface, respectively, and a gap is provided between an outer peripheral surface of the annular filter and the peripheral wall portion of the housing.

2. The gas generator according to claim 1, wherein the first angle and the second angle are determined, such that an angle formed by the top plate and the upper annular inclined surface and an angle formed by the bottom plate and the lower annular inclined surface are substantially the same as an angle formed by the top plate before bulging and by the top plate after bulging, and an angle formed by the bottom plate before bulging and by the bottom plate after bulging, respectively.

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

4. The gas generator according to claim 1, wherein the annular plane abuts against the top plate, and the ignition means is accommodated and fixed in an open portion at the lower end of the tubular member;

and

an outer peripheral edge of the annular plane abuts against an inner peripheral surface of the annular filter and covers, from an inside, a contact portion of the top plate and the upper end surface of the annular filter.

5. The gas generator according to claim 4, wherein the recessed portion is formed in a central part of the top plate.

6. An air bag apparatus, comprising:

the gas generator according to claim 1 or 2.

10. The gas generator according to claim 4, wherein the second combustion chamber, that accommodates a second gas generating agent therein, is defined between the tubular member and the annular filter.

7. A gas generator, comprising:

a housing including a top plate, a bottom plate, and a peripheral wall including a gas discharge port, the housing further including an upper annular inclined surface formed between the peripheral wall and the top plate, and a lower annular inclined surface formed between the peripheral wall and the bottom plate, the upper annular inclined surface and the lower annular inclined surface encircling the top plate and the bottom plate, respectively, the top plate and the bottom plate bulging outwardly upon activation of the gas generator, the bottom plate being provided with a hole;

a collar attached directly to the hole;

a tubular member including an upper end and a lower end and provided concentrically with respect to and within the housing such that the lower end is in engagement with the collar and the tubular member defines, in an inner side and an outer side thereof, a first combustion chamber, accommodating a first gas generating agent, and a second combustion chamber, accommodating a second gas generating agent, respectively, the tubular member being provided with a reduced-diameter portion forming a step in the upper end, and a main portion having a diameter larger than the reduced-diameter portion, a plurality of communication holes for communicating the first combustion chamber with the second combustion chamber being provided only in the main portion;

an annular plane extending in a radial direction of the housing from the upper end of the tubular member and including, in an inner side thereof, a bent portion, and being provided such that the bent portion abuts against the step; and

an annular filter provided inside the housing so as to surround the tubular member, such that a top end and a bottom end of the annular filter keep abutting the upper annular inclined surface and the lower annular inclined surface, respectively, upon an activation of the gas generator, while the top plate and the bottom plate bulge outwardly,

wherein a first angle between an imaginary extension line of the top plate before bulging and an imaginary tangential line of the top plate after bulging is substantially equal to a second angle between the imaginary extension line of the top plate and the upper annular inclined surface,

wherein a third angle between an imaginary extension line of the bottom plate before bulging and an imaginary tangential line of the bottom plate after bulging is substantially equal to a fourth angle between the imaginary extension line of the bottom plate and the lower annular inclined surface.

8. A gas generator according to claim 7, wherein the annular filter is pressed, inside the housing, by the upper annular inclined surface and the lower annular inclined surface in an axial direction of the housing, and a gap is provided between an outer peripheral surface of the annular filter and the peripheral wall of the housing.

9. A gas generator according to claim 7, wherein the annular plane extends, from the upper end of the tubular member, in a radial direction of the housing such that a distal end of the annular plane abuts an inner surface of the annular filter.

11. The gas generator according to claim 9, wherein the second combustion chamber, that accommodates a second gas generating agent therein, is defined between the tubular member and the annular filter.