WO2018147020A1

WO2018147020A1 - Gas generator

Info

Publication number: WO2018147020A1
Application number: PCT/JP2018/001199
Authority: WO
Inventors: 浮田信一朗; 冨田大空
Original assignee: 株式会社ダイセル
Priority date: 2017-02-09
Filing date: 2018-01-17
Publication date: 2018-08-16
Also published as: JP2018127115A; JP6710167B2

Abstract

The present invention provides a gas generator in which: a pressurized gas chamber is disposed between an ignition chamber disposed on a first end side of a cylindrical housing, and a diffuser part having a gas discharge hole and disposed on a second end side; a first communication hole between the ignition chamber and the pressurized gas chamber is closed by a first rupture member; a cap member is disposed between the first rupture member and the pressurized gas chamber; a second communication hole between the pressurized gas chamber and the diffuser part is closed by a second rupture member; the cap member has a porous cylindrical peripheral wall part, a bottom surface part, and an opening part; the bottom surface part has a recess section serving as a gas discharge passage and disposed across the cylindrical peripheral wall part and the bottom surface part; the opening is covered with the first rupture member and fixed; the bottom surface part is mounted to be positioned on the second communication hole side; the bottom surface part of the cap member has a diameter greater than the inner diameter of the second communication hole; and when the center of the bottom surface part of the cap member and the center of the second communication hole are aligned with each other, at least a portion of the recess section, serving as the gas discharge passage, of the bottom surface part faces the second communication hole.

Description

Gas generator

The present invention relates to a gas generator that can be used in an airbag device mounted on an automobile.

BACKGROUND ART A gas generator used in an airbag apparatus includes a type in which an airbag is inflated with a pressurized gas such as argon or helium. In such a gas generator, the gas discharge path is closed by a metal rupture member before operation, and the gas discharge path is opened by breaking the rupture member during operation. For this reason, when fragments of the rupture member are generated during operation, it is important to capture the fragments so that they are not discharged out of the gas generator.

JP 2003-226222A discloses a gas generator 10 having a pressurized gas chamber housing 22 and a gas generator housing 32. A cap 44 is attached to the pressurized gas chamber 20 so as to cover the first rupturable plate 40. The cap 44 is fixed by caulking a part (caulking portion) 48 of the gas generator housing 32 with the flange portion 46 on the opening end side.

In JP2005-225346A, an outer shell is formed by a cylindrical inflator housing 12, a cylindrical closure 20 welded and fixed to one end opening side of the inflator housing 12, and a diffuser 50 welded and fixed to the other end side. An inflator 10 is disclosed. A cap 40 that covers the first rupturable plate 35 is disposed in the internal space (which serves as a pressurized gas chamber) 14 of the inflator housing 12. When the cap 40 is pushed into the inflator housing 12, it is fixed by pressing the inner peripheral surface of the inflator housing 12 and the inner peripheral surface of the closure 20 with a part of the outer peripheral surface.

DISCLOSURE OF THE INVENTION A first aspect of the present invention (hereinafter referred to as “first aspect”) includes an ignition chamber in which an igniter is accommodated on a first end side of a cylindrical housing, and the first end part And a diffuser part in which a gas discharge port is formed on the second end side opposite to the axial direction, and a pressurized gas chamber is provided between the ignition chamber and the diffuser part,
Between the ignition chamber and the pressurized gas chamber, a first communication hole surrounded by a first annular wall is closed by a first rupture member fixed to the first annular wall, and further, the first rupture A cap member is disposed between the member and the pressurized gas chamber;
Between the pressurized gas chamber and the diffuser portion, the second communication hole surrounded by the second annular wall portion is closed by the second rupturable member,
The cap member is
A cylindrical peripheral wall portion, a bottom surface portion closed at one end of the cylindrical peripheral wall portion, and an opening opposite to the bottom surface portion; and the cylindrical peripheral wall portion has a porous structure. The bottom surface portion has a concave portion that is in contact with a boundary portion between the cylindrical peripheral wall portion and the bottom surface portion, and serves as a gas discharge path spanning the cylindrical peripheral wall portion and the bottom surface portion.
An outer diameter of the cylindrical peripheral wall portion is smaller than an inner diameter of the cylindrical housing;
The opening is covered with the first rupturable member and fixed to the first annular wall or the cylindrical housing, and the bottom is attached so as to be positioned on the second communication hole side. ,
When the diameter of the bottom surface portion of the cap member is larger than the inner diameter of the second communication hole and the center of the bottom surface portion of the cap member is aligned with the center of the second communication hole, A gas generator is provided in which at least a part of the concave portion faces the second communication hole.

A second aspect of the present invention (hereinafter referred to as “second aspect”) has an ignition chamber in which an igniter is accommodated on the first end side of the cylindrical housing, and is axially opposite to the first end part. A diffuser portion having a gas discharge port formed on the second end portion side, and a pressurized gas chamber between the ignition chamber and the diffuser portion;
Between the ignition chamber and the pressurized gas chamber, a first communication hole surrounded by a first annular wall is closed by a first rupture member fixed to the first annular wall, and further, the first rupture A cap member is disposed between the member and the pressurized gas chamber;
Between the pressurized gas chamber and the diffuser portion, the second communication hole surrounded by the second annular wall portion is closed by the second rupturable member,
The cap member is
A cylindrical peripheral wall portion, a bottom surface portion closed at one end of the cylindrical peripheral wall portion, and an opening opposite to the bottom surface portion; and the cylindrical peripheral wall portion has a porous structure. ,
An outer diameter of the cylindrical peripheral wall portion is smaller than an inner diameter of the cylindrical housing;
The opening is covered with the first rupturable member and fixed to the first annular wall or the cylindrical housing, and the bottom is attached so as to be positioned on the second communication hole side. ,
The second annular wall portion has a recess serving as a gas discharge path extending radially outward from a boundary portion with the second communication hole in the second annular surface on the pressurized gas chamber side;
When the diameter of the bottom surface portion of the cap member is larger than the inner diameter of the second communication hole and the center of the bottom surface portion of the cap member is aligned with the center of the second communication hole, the concave portion becomes the bottom surface of the cap member. A gas generator is provided that extends radially outward from the portion.

The present invention will be more fully understood from the following detailed description and the accompanying drawings. However, these are merely for the purpose of explanation and are not intended to limit the present invention.

FIG. 1A is a cross-sectional view in the direction of the axis X showing an embodiment of the gas generator of the present invention in FIG. 1A, and FIG. FIG. FIG. 2 is a perspective view showing different embodiments of cap members that can be used in the gas generator of FIG. 1 in (a) to (d). FIG. 3 is a partial sectional view showing a state when the gas generator of FIG. 1 operates abnormally. FIG. 4 is an axial sectional view showing still another embodiment of the cap member. 5A is a perspective view showing still another embodiment of the cap member in FIG. 5A, and FIG. 5B is a schematic plan view from the distal end portion direction of FIG. 6A is a partial cross-sectional view in the axial direction showing a state when the gas generator according to another embodiment is abnormally operated in FIG. 6A, and FIG. 6B is a plan view inside the diffuser portion in FIG. .

DETAILED DESCRIPTION OF THE INVENTION In the present invention, even when a cap member attached to a pressurized gas chamber is removed and collides with a diffuser portion serving as a gas discharge path, the gas discharge path is not blocked. A gas generator capable of securing a gas discharge path is provided.

The ignition chamber may be accommodated in a cylindrical housing, or may be accommodated in an ignition chamber housing different from the cylindrical housing. When using the ignition chamber housing, the ignition chamber housing is welded and fixed to the first end side of the cylindrical housing. A known electric igniter is accommodated in the ignition chamber, and further, a known gas generating agent or a known explosive charge may be accommodated.

A diffuser portion having a gas discharge port is provided on the second end side of the cylindrical housing. The diffuser portion may be formed by welding another member having a gas discharge port to the second end side of the cylindrical housing, or forming the gas discharge port at the second end portion of the closed cylindrical housing. The diffuser part may be used.

As the separate member having the gas discharge port, a cup-shaped member in which a plurality of gas discharge ports are formed on the peripheral wall portion or both the peripheral wall portion and the bottom surface portion is preferable. Moreover, when using a cup-shaped diffuser part, what has a flange part in an opening part can be used, and a flange part can also be made into the thing welded to the 2nd end part of the cylindrical housing.

The first communication hole is surrounded by a first annular wall between the ignition chamber and the pressurized gas chamber. The first annular wall portion protrudes inward in the radial direction from the inner peripheral wall surface of the cylindrical housing, and may be formed integrally with the cylindrical housing, or may be another annular member in the cylindrical housing. May be fixed by welding.

When the ignition chamber housing is used, a first annular wall portion may be formed on the inner peripheral wall surface of the ignition chamber housing.

The first communication hole is closed with a first rupturable member fixed to the first annular wall. The first rupturable member is a disc-shaped member made of a metal such as iron or stainless steel, and its peripheral edge is welded to the first annular wall.

The second communication hole is surrounded by the second annular wall portion between the pressurized gas chamber and the diffuser portion. The second annular wall portion may be protruded inward in the radial direction from the inner peripheral wall surface of the cylindrical housing, and when the diffuser portion has a flange portion, the flange portion is used as the second annular wall. It can also be a part.

The second communication hole is closed with a second rupturable member fixed to the second annular wall. The second rupturable member is a disc-shaped member made of a metal such as iron or stainless steel, and its peripheral edge is welded to the second annular wall.

The cap member has a cylindrical peripheral wall portion, a bottom surface portion where one end portion of the cylindrical peripheral wall portion is closed, and an opening portion on the opposite side to the bottom surface portion. A short flange portion may be formed in the opening.

The cylindrical peripheral wall portion has a porous structure, and the porous hole serves as a passage hole for combustion products such as combustion gas and flame generated in the ignition chamber.

The bottom surface of the cap member has a recess that serves as a gas discharge path. The recess serving as the gas discharge path is formed so as to contact the boundary portion between the cylindrical peripheral wall portion and the bottom surface portion and to straddle the cylindrical peripheral wall portion and the bottom surface portion.

The concave portion may be one in which a concave portion (including a groove) is formed on a flat bottom surface portion, or a convex portion is formed on the flat bottom surface portion so that a portion where the convex portion is not formed becomes a concave portion. It may be what you have. The recess may be formed only on the bottom surface as long as it touches the boundary portion between the cylindrical peripheral wall portion and the bottom surface portion and straddles both, or is formed across the cylindrical peripheral wall portion and the bottom surface portion. It may be a thing.

The cap member is attached so that the opening portion covers at least the non-welded portion of the first rupturable member and the bottom portion is positioned on the second rupturable member side. The cap member is made of a metal such as iron or stainless steel.

The cap member is fixed to the first annular wall or the cylindrical housing. As a fixing method, methods such as welding, fitting by a combination of unevenness, caulking same as JP2003-226222A, press-fitting same as JP2005-225346A can be applied.

When the diameter of the bottom surface portion of the cap member is larger than the inner diameter of the second communication hole (second annular wall portion) and the center of the bottom surface portion of the cap member is aligned with the center of the second communication hole, the gas of the bottom surface portion At least a part of the concave portion serving as the discharge path faces the second communication hole.

The ratio (d1 / d2) of the diameter (d1) of the bottom surface portion of the cap member to the inner diameter (d2) of the second communication hole is preferably 1.1 to 2.5.

When the combustion gas is generated by the operation of the igniter in the ignition chamber and the pressure rises, the first rupture member is destroyed and the first communication hole is opened. Thereafter, when the combustion gas passes through the pores of the cap member and enters the pressurized gas chamber to increase the pressure, the second rupturable member is destroyed and the second communication hole is opened.

When the fragments of the first rupture member are generated, they are trapped by the porous portion of the cap member, and therefore do not enter the pressurized gas chamber. When fragments of the second rupturable plate are generated, they are captured at the gas discharge port of the diffuser portion, and thus do not come out of the gas generator.

The gas generator according to the present invention does not operate normally as described above, but operates abnormally such that the cap member is removed during operation, and the bottom surface of the cap member moved in the direction of the diffuser portion contacts the second communication hole. Even if it is in the state (the diameter of the bottom surface portion of the cap member> the inner diameter of the second communication hole), the second communication hole is not blocked because at least a part of the recess faces the second communication hole. For this reason, the gas discharge path is maintained even when the above-described abnormal operation occurs.

In the gas generator according to a preferred aspect of the first aspect, the concave portion serving as the gas discharge path of the bottom surface portion of the cap member includes a plurality of independent concave portions.

The plurality of independent recesses can be formed such that 2 to 8 recesses are formed at equal intervals in the circumferential direction in a state of straddling the bottom surface portion and the cylindrical peripheral wall portion of the cap member. . The shape of the recess may be a semicircular, triangular, quadrangular, etc. cross section in the width direction.

In another preferred aspect of the gas generator according to the first aspect, the concave portion serving as the gas discharge path of the bottom surface portion of the cap member is formed of a portion excluding the convex portion formed on the bottom surface portion.

The shape, size, number and arrangement state of the convex portions are not particularly limited. For example, a plurality of independent cylindrical protrusions may be formed in the circumferential direction or randomly at equal intervals, or one arbitrary shape protrusion (+ shape, X shape, etc.) may be formed. it can.

In the gas generator according to still another preferred aspect of the first aspect, the concave portion serving as the gas discharge path of the bottom surface portion of the cap member extends from the center of the bottom surface portion to a boundary portion between the peripheral wall portion and the bottom surface portion, or It comprises a plurality of grooves extending radially across the peripheral wall portion and the bottom surface portion.

About 3 to 8 grooves that are radially extended can be formed. The width and depth of the groove are not particularly limited as long as they can function as a gas discharge path.

In the gas generator according to the first aspect and the preferred aspect of the first aspect, the cap member is attached to the bottom surface portion and the cap member main body portion including the cylindrical peripheral wall portion, the bottom surface portion, and the opening portion. It is preferable to be a combination of the tip portions of different members having recesses that serve as gas discharge paths.

The cap member main body portion and the tip portion may be fixed by welding, or may be detachably attached by screwing or fitting.

The gas generator according to the first aspect and the preferred aspect of the first aspect is characterized in that the bottom surface portion of the cap member has a recess serving as a gas discharge passage. The gas discharge passage extends radially outward from the boundary with the second communication hole in the second annular surface of the second annular wall portion on the pressurized gas chamber side instead of the concave portion of the bottom surface portion of the cap member. It is the feature that it has the recessed part which becomes. And when the center of the bottom face part of a cap member and the center of the 2nd communicating hole are match | combined, the recessed part has extended in the radial direction outer side rather than the bottom face part of the cap member.

When the gas generator according to the present invention operates abnormally such that the cap member is detached during operation, and the bottom surface of the cap member that has moved in the direction of the diffuser portion is in contact with the second communication hole. However (the diameter of the bottom surface portion of the cap member> the inner diameter of the second communication hole), the second communication hole is not blocked by the recess formed in the second annular surface. For this reason, the gas discharge path is maintained even when the above-described abnormal operation occurs.

In the gas generator of the first aspect, the preferred aspect of the first aspect, and the second aspect, it is preferable that the bottom surface of the cap member has a protrusion at the center.

When the gas generator according to the first aspect, the preferred aspect of the first aspect, and the second aspect performs an abnormal operation as described above, the protrusion on the bottom surface of the cap member moved in the direction of the diffuser portion is the second. It is preferable because it collides with the rupture member, and the second rupture member can be destroyed by the collision or the destruction of the second rupture plate can be assisted.

The shape and structure of the protrusion are not particularly limited. For example, a cylindrical protrusion or a conical protrusion formed at the center of the cap member, and three or more plate members so as to have an arrowhead shape as a whole. It can be combined.

In the gas generator of the present invention, even when an abnormal operation occurs in which the cap member attached to the pressurized gas chamber is detached and moves to the second communication hole, the second communication hole is not blocked. A gas discharge path from the pressurized gas chamber to the gas discharge port is secured.

The gas generator of the present invention can be used as a gas generator for an airbag device mounted on an automobile.

Embodiments of the Invention (1) Gas Generator Shown in FIGS. 1A and 1B The gas generator 1 has an ignition chamber 20 on the first end portion 10a side of the cylindrical housing 10, and the first A diffuser portion 40 is provided on the second end portion 10 b side opposite to the end portion 10 a in the axial X direction, and a pressurized gas chamber 30 is provided between the ignition chamber 20 and the diffuser portion 40.

The cylindrical housing 10 is made of metal such as iron or stainless steel.

The ignition chamber 20 is formed in an ignition chamber housing 21 made of metal such as iron or stainless steel.

The ignition chamber housing 21 has an electric igniter 22 fixed to the first end portion 21a side, and the second end portion 21b enters the inside of the first end portion 10a of the cylindrical housing 10 so that the contact portion Are welded.

A gas generating agent 23 is accommodated in the ignition chamber 20.

On the inner side of the ignition chamber housing 21 in the vicinity of the second end portion 21b, there is a first annular wall portion 25 protruding radially inward from the inner peripheral wall portion of the housing, and is surrounded by the first annular wall portion 25. The portion is a first communication hole 26. The first communication hole 26 communicates the ignition chamber 20 and the pressurized gas chamber 30 during operation.

The first communication hole 26 is closed by a first rupture member 27 fixed to the first annular wall portion 25 from the pressurized gas chamber 30 side, and a cap is interposed between the first rupture member 27 and the pressurized gas chamber 30. A member 50 is arranged.

The first rupturable member 27 is a disk made of metal such as iron or stainless steel, and the peripheral edge is welded to the first annular surface 25a of the first annular wall 25 on the pressurized gas chamber 30 side. FIG. 1 shows a state in which the first rupturable member 27 is deformed into a bowl shape under the pressure from the pressurized gas chamber 30.

The pressurized gas chamber 30 is a space filled with a high pressure gas such as argon or helium. The gas is filled from a gas injection hole formed in the peripheral wall portion of the cylindrical housing 10, and the gas injection hole after the gas filling is closed by being welded to the cylindrical housing 10 together with the insertion pin 31.

The cap member 50 has a cylindrical peripheral wall portion 51, a bottom surface portion 52 where one end portion of the cylindrical peripheral wall portion 51 is closed, and an opening 53 on the opposite side of the bottom surface portion 52. The cylindrical peripheral wall portion 51 has a porous structure having a large number of gas passage holes 51a.

The bottom surface portion 52 has a recess 55 that serves as a gas discharge path. The concave portion 55 is formed so as to contact the boundary portion between the cylindrical peripheral wall portion 51 and the bottom surface portion 52 and to straddle both.

The inner diameter (D1) of the cylindrical housing 10 and the outer diameter (D2) of the cap member 50 are such that D1 / D2 is in the range of 1.1 to 2.0, and preferably in the range of 1.15 to 1.20. .

The cap member 50 is attached to the first rupturable member 27 from the pressurized gas chamber 30 side so that the bottom surface portion 52 is located on the diffuser portion 40 side.

In the cap member 50, the opening 53 is brought into contact with the first annular surface 25 a of the first annular wall 25 on the pressurized gas chamber 30 side (periphery of the first rupturable member 27) (first contact portion). The outer peripheral surface of the cylindrical peripheral wall portion 51 on the opening 53 side is in contact with the inner peripheral wall surface 21c of the ignition chamber housing 21 on the second end portion 21b side (second contact portion). In the second contact portion, the cap member 50 is fixed to the ignition means chamber housing 21 by press-fitting or welding.

The diffuser portion 40 includes a bottom surface portion 41, a peripheral wall portion 42 extending in one direction from the bottom surface portion 41, and an opening portion 43 (see FIG. 3) facing the bottom surface portion 41 in the axial direction. A portion 44 is formed. The peripheral wall portion 42 has a plurality of gas discharge ports 45.

The diffuser portion 40 is welded to the second end portion 10b of the cylindrical housing at the periphery of the flange portion 44.

A second annular wall portion is formed between the diffuser portion 40 and the second end portion 10b of the cylindrical housing 10, and the second annular wall portion has a cup-shaped diffuser portion (no flange portion or a short flange). It is also possible to adopt a structure in which a cup-shaped part having a portion is fixed by welding.

In the present embodiment, the flange portion 44 serves as a second annular wall portion, the opening portion 43 serves as a second communication hole, and the second communication hole (opening portion) 43 is closed by the second rupturable member 46.

The second rupturable member 46 is a disk made of metal such as iron or stainless steel, and the peripheral edge is welded to the second annular wall (flange) 44 from the pressurized gas chamber 30 side. FIG. 1 shows a state where the second rupturable member 46 is deformed into a bowl shape under the pressure from the pressurized gas chamber 30.

The cap member 50 can be, for example, that of the embodiment shown in FIGS. 2 (a) to 2 (d).

The cap member 50A shown in FIG. 2A has a cylindrical peripheral wall portion 51, a bottom surface portion 52, and an opening 53. The cylindrical peripheral wall portion 51 has a number of gas passage holes 51a.

The bottom surface portion 52 has a concave portion 55a that is in contact with the boundary portion between the cylindrical peripheral wall portion 51 and the bottom surface portion 52 and extends from there to the cylindrical peripheral wall portion 51 side and the bottom surface portion 52 side. A total of four are formed at equal intervals. The concave portion 55a has a rhombus shape when viewed from the opposite position.

2B has a cylindrical peripheral wall portion 51, a bottom surface portion 52, and an opening 53, and the cylindrical peripheral wall portion 51 is formed with a large number of gas passage holes 51a.

The bottom surface portion 52 is formed with a convex portion 56 having a + shape in the planar shape passing through the center of the bottom surface portion 52, and the portion excluding the + shape convex portion 56 has four quarter-circle concave portions 55 b. Is formed.

The concave portion 55b is in contact with the cylindrical peripheral wall portion 51 and the bottom surface portion 52 and extends over both.

2C has a cylindrical peripheral wall portion 51, a bottom surface portion 52, and an opening 53, and the cylindrical peripheral wall portion 51 is formed with a large number of gas passage holes 51a.

In the bottom surface portion 52, six independent convex portions 57 are formed at equal intervals in the circumferential direction along the peripheral edge of the bottom surface portion 52, and a continuous concave portion 55c is formed in a portion excluding the convex portion 57. Has been.

The concave portion 55c is in contact with the boundary portion between the cylindrical peripheral wall portion 51 and the bottom surface portion 52, and is in a state of straddling both.

2D has a cylindrical peripheral wall portion 51, a bottom surface portion 52, and an opening 53, and the cylindrical peripheral wall portion 51 has a number of gas passage holes 51a.

The bottom surface portion 52 is formed with three grooves (concave portions) 55d radially extending from the center hole 58 of the bottom surface portion 52 to the boundary portion between the cylindrical peripheral wall portion 51 and the bottom surface portion 52 so as to straddle both. Yes. The center hole 58 also functions as a gas discharge path, like the three grooves (recesses) 55d. The center hole 58 does not penetrate the bottom surface portion 52, and has a reduced thickness similar to the groove 55d.

The groove (concave portion) 55d is in contact with the boundary portion between the cylindrical peripheral wall portion 51 and the bottom surface portion 52, and is in a state of straddling both.

In the gas generator 1 of the present invention, the bottom surface portion 52 of the cap member 50 and the second communication hole (opening portion) 43 have the same diameter (d1) of the bottom surface portion 52 of the cap member 50 as the inner diameter (d2) of the second communication hole 43. ) (D1> d2), and when the center of the bottom surface portion 52 of the cap member 50 (matches the axis X) and the center of the second communication hole 43 (matches the axis X) match, At least a part of the recess 55 serving as a path faces the second communication hole 43. d1 / d2 is adjusted to about 1.5.

The operation when the gas generator 1 of FIG. 1 is used as a gas generator for an air bag device will be described. The cap member 50 will be described as using the cap member 50A shown in FIG.

When the gas generating agent 23 is ignited and combusted by the operation of the igniter 22 in the ignition chamber 20 to generate combustion gas and the pressure rises, the first rupture member 27 is broken and the first communication hole 26 is opened.

Thereafter, the combustion gas enters the pressurized gas chamber 30 from the first communication hole 26 through the gas passage hole 51a of the cap member 50A. When the pressure in the pressurized gas chamber 30 is increased, the second rupturable member 46 is broken and the second communication hole 43 is opened.

Thereafter, the mixed gas of the combustion gas and the pressurized gas that has passed through the second communication hole 43 enters the diffuser portion 40 and is then discharged from the gas discharge port 45 to inflate the airbag.

When a fragment of the first rupture member 27 is generated, it is captured by the gas passage hole 51a of the cap member 50, and therefore does not enter the pressurized gas chamber 30.

When a fragment of the second rupture member 46 is generated, it is captured by the gas discharge port 45 of the diffuser section 40 and therefore does not come out of the gas generator 1.

Next, a case will be described in which the gas generator 1 does not operate normally as described above but performs an abnormal operation in which the cap member 50A is detached during operation.

Thereafter, the combustion gas enters the pressurized gas chamber 30 from the first communication hole 26 through the gas passage hole 51a of the cap member 50A, and the second rupture member 46 is destroyed due to an increase in pressure. Is released.

When the cap member 50A is detached in this process, the cap member 50A moves in the direction of the second rupturable member 46 together with the gas flow as shown in FIG. 3, and abuts against the flange portion 44 to close the second communication hole 43. It will stop in such a state. When the cap member 50A is detached, the second rupturable member 46 may not be destroyed, or there may be a crack or the like that is not completely destroyed.

However, four concave portions 55 a are formed on the bottom surface portion 52 of the cap member 50 A, and the four concave portions 55 a span both the second annular wall portion (flange portion) 44 and the second communication hole 43. Therefore, a gas discharge path from the pressurized gas chamber 30 to the second communication hole 43 is secured.

For this reason, even when the above-described abnormal operation occurs, the gas discharge path from the pressurized gas chamber 30 to the gas discharge port 45 is maintained, and the airbag is reliably inflated.

FIG. 3 shows a state in which the central axis (axis X) of the cylindrical housing and the central axis (axis X) of the cap member 50 coincide with each other. For example, the central axes do not coincide with each other and are displaced. Even when the cylindrical peripheral wall portion 51 is in contact with the inner peripheral wall surface of the cylindrical housing 10, the pressurized gas chamber 30 and the second communication hole 43 are communicated with each other by any of the recesses 55a. Therefore, a gas discharge path from the pressurized gas chamber 30 to the second communication hole 43 is secured.

(2) Gas generator using the cap member shown in FIG. 4 A cap member 50E shown in FIG. 4 has the same structure as that shown in FIGS. This is the same as any one of the cap members 50A to 50E shown in FIG.

The protrusion 59 has a height that allows it to collide with the second rupturable member 46 when it reaches the state shown in FIG.

When the cap member 50E is detached and the bottom surface portion 52 comes into contact with the flange portion 44 after the abnormal operation similar to that of the gas generator 1 of FIG. 1, the second rupturable member 46 is not broken or cracked. However, it is preferable that the protrusion 59 collides with the second rupturable member 46 so that the breakage of the second rupturable member 46 is easily promoted.

(3) Gas generator using the cap member shown in FIGS. 5 (a) and 5 (b) A cap member 80 shown in FIG. 5 has a cylindrical peripheral wall portion 82 having a large number of gas passage holes 82a, a bottom surface portion 83, and an opening. The cap member main body portion 81 formed of the portion 84 and a distal end portion 85 of another member attached to the bottom surface portion 83 are combined.

The cap member body 81 and the tip 85 may be detachable by a method such as screwing or fitting, or may be integrated by welding or the like.

The tip portion 85 shown in FIG. 5 is formed by combining six plate members 91 to 96 at equal intervals in the circumferential direction so as to have an arrowhead shape as a whole. In FIG. 5A, only three plate members 91 to 93 are shown, and the remaining three plate members are in a position where they cannot be seen. Each of the six plate members has a slope from the center to the outside in the radial direction.

The space between the six plate members is a recess 90 serving as a gas discharge path.

When the cap member 80 is detached and moved to the second rupturable member 46 by performing an abnormal operation similar to that of the gas generator 1 in FIG. 1, the tip end portion 85 collides with the second rupturable member 46. Is not broken, or has cracks or the like but is not completely broken, it is preferable because the second rupturable member 46 is more easily broken. At this time, the inclined surface of each plate material abuts on the inner peripheral edge of the second communication hole 43, and a gas discharge path is formed between the inner peripheral edge and the recess 90.

Even when the distal end portion 85 of the cap member 80 that has broken the second rupturable member 46 enters the second communication hole 43, the pressurized gas chamber 30 and the second communication hole 43 are communicated with the concave portions 90 at a plurality of locations. Therefore, a gas discharge path from the pressurized gas chamber 30 to the gas discharge port 45 is secured.

(4) Gas generator shown in FIG. 6 The gas generator 100 shown in FIG. 6 (a) is different from the gas generator 1 shown in FIG. This is the same except that the flange portion (second annular wall portion) 144 of the diffuser portion 140 has a recess 155 that serves as a gas discharge path. FIG. 6 is a drawing corresponding to FIG. 3, but the second rupture member after rupture is not shown.

The cap member 150 includes a cylindrical peripheral wall portion 151, a bottom surface portion 152 in which one end portion of the cylindrical peripheral wall portion 151 is closed, and an opening portion (not shown) on the opposite side to the bottom surface portion 152 of the cylindrical peripheral wall portion 151. have. The cylindrical peripheral wall portion 151 has a porous structure having a large number of gas passage holes 151a. Although the bottom surface 152 is a flat surface, the same portion as the projection 59 in FIG. 4 can be formed in the center.

The inner diameter (D1) of the cylindrical housing 10 and the outer diameter (D2) of the cap member 150 are such that D1 / D2 is in the range of 1.1 to 2.0.

The diffuser portion 140 includes a bottom surface portion 141, a peripheral wall portion 142 extending in one direction from the bottom surface portion 141, and an opening portion 143 facing the bottom surface portion 141 in the axial direction, and a flange portion 144 is formed in the opening portion 143. ing. The peripheral wall 142 has a plurality of gas discharge ports 145.

The peripheral wall 142 has an annular step surface 146 for fixing the second rupturable plate to the inner peripheral surface close to the opening 143.

As shown in FIG. 6B, the flange portion 144 has four concave portions 155 formed at equal intervals in the circumferential direction on the second annular surface 144a facing the pressurized gas chamber 30. The recess 155 extends in the radial direction from the second communication hole (opening) 143 so as to protrude outward in the radial direction from the outer peripheral edge of the bottom surface portion 152 of the cap member 150.

In this embodiment, the flange portion 144 serves as the second annular wall portion, the opening portion 143 serves as the second communication hole, and the second communication hole (opening portion) 143 is closed by the second rupture member.

In the diffuser part 140, the peripheral edge part of the flange part 144 is welded to the second end part 10b of the cylindrical housing.

When the gas generator 100 of FIG. 6 performs the same abnormal operation as that of the gas generator 1 of FIG. 1 and the cap member 150 is detached and moved, the bottom surface portion 152 becomes the second annular surface of the diffuser portion 140 (the flange portion 144). (Pressurized gas chamber side surface) 144a.

However, four concave portions 155 are formed in the second annular surface 144a, and the pressurized gas chamber 30 and the second communication hole 143 communicate with each other through the concave portion 155. Therefore, from the pressurized gas chamber 30 to the gas discharge port 145, The gas discharge route is secured.

The invention has been described above. Of course, the present invention includes within its scope various modifications, which do not depart from the scope of the present invention. Also, all that would be considered obvious variations of the present invention by those having ordinary skill in the art are within the scope of the claims set forth below.

Claims

The tubular housing has an ignition chamber in which an igniter is accommodated on the first end portion side, and a diffuser portion in which a gas discharge port is formed on the second end portion side opposite to the first end portion in the axial direction. And having a pressurized gas chamber between the ignition chamber and the diffuser part,
Between the ignition chamber and the pressurized gas chamber, a first communication hole surrounded by a first annular wall is closed by a first rupture member fixed to the first annular wall, and further, the first rupture A cap member is disposed between the member and the pressurized gas chamber;
Between the pressurized gas chamber and the diffuser portion, the second communication hole surrounded by the second annular wall portion is closed by the second rupturable member,
The cap member is
A cylindrical peripheral wall portion, a bottom surface portion closed at one end of the cylindrical peripheral wall portion, and an opening opposite to the bottom surface portion; and the cylindrical peripheral wall portion has a porous structure. The bottom surface portion has a concave portion serving as a gas discharge path extending over the cylindrical peripheral wall portion and the bottom surface portion,
An outer diameter of the cylindrical peripheral wall portion is smaller than an inner diameter of the cylindrical housing;
The opening is covered with the first rupturable member and fixed to the first annular wall or the cylindrical housing, and the bottom is attached so as to be positioned on the second communication hole side. ,
When the diameter of the bottom surface portion of the cap member is larger than the inner diameter of the second communication hole and the center of the bottom surface portion of the cap member is aligned with the center of the second communication hole, A gas generator in which at least a part of the concave portion faces the second communication hole.
The gas generator according to claim 1, wherein the concave portion serving as a gas discharge path in the bottom surface portion of the cap member is composed of a plurality of independent concave portions.
The gas generator according to claim 1, wherein the concave portion serving as a gas discharge path in the bottom surface portion of the cap member is a portion excluding the convex portion formed in the bottom surface portion.
2. The concave portion serving as a gas discharge path in the bottom surface portion of the cap member is composed of a plurality of grooves radially extending from the center of the bottom surface portion to the peripheral wall portion and the bottom surface portion. Gas generator.
The cap member is a combination of a cap member main body portion composed of the cylindrical peripheral wall portion, the bottom surface portion and the opening, and a tip portion of another member attached to the bottom surface portion and having a recess serving as a gas discharge path. The gas generator according to any one of claims 1 to 4, wherein
The tubular housing has an ignition chamber in which an igniter is accommodated on the first end portion side, and a diffuser portion in which a gas discharge port is formed on the second end portion side opposite to the first end portion in the axial direction. And having a pressurized gas chamber between the ignition chamber and the diffuser part,
Between the ignition chamber and the pressurized gas chamber, a first communication hole surrounded by a first annular wall is closed by a first rupture member fixed to the first annular wall, and further, the first rupture A cap member is disposed between the member and the pressurized gas chamber;
Between the pressurized gas chamber and the diffuser portion, the second communication hole surrounded by the second annular wall portion is closed by the second rupturable member,
The cap member is
A cylindrical peripheral wall portion, a bottom surface portion closed at one end of the cylindrical peripheral wall portion, and an opening opposite to the bottom surface portion; and the cylindrical peripheral wall portion has a porous structure. ,
An outer diameter of the cylindrical peripheral wall portion is smaller than an inner diameter of the cylindrical housing;
The opening is covered with the first rupturable member and fixed to the first annular wall or the cylindrical housing, and the bottom is attached so as to be positioned on the second communication hole side. ,
The second annular wall portion has a recess serving as a gas discharge path extending radially outward from a boundary portion with the second communication hole in the second annular surface on the pressurized gas chamber side;
When the diameter of the bottom surface portion of the cap member is larger than the inner diameter of the second communication hole and the center of the bottom surface portion of the cap member is aligned with the center of the second communication hole, the concave portion becomes the bottom surface of the cap member. A gas generator extending radially outward from the section.
The gas generator according to any one of claims 1 to 6, wherein the bottom surface of the cap member has a protrusion at the center.