JP3041120B2 - Means for fixing igniter in gas generator for airbag - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas generator for an air bag for protecting an occupant from an impact, and more particularly to a fixing means for an igniter.

[0002]

2. Description of the Related Art Conventionally, as a method of attaching an igniter to a gas generator, caulking, an adhesive or the like is generally used.

[0003]

However, fixing by caulking imposes a load on the igniter, which poses a problem in work safety. In addition, fixing with an adhesive requires a series of operations such as application, attachment, and drying, and has a problem that it takes a long time to attach (usually 24 hours). Furthermore, when fixing to a predetermined position in the circumferential direction, there is a problem that the work must be performed while checking the position at the time of mounting.

Accordingly, an object of the present invention is to provide a means for fixing an igniter in a gas generator for an air bag, which solves the above-mentioned problems of the prior art.

[0005]

Means for fixing an igniter in a gas generator according to the present invention include a housing, a gas generating agent disposed in the housing, and an igniter for burning the gas generating agent. Gas having an opening communicating the housing and the airbag, and introducing gas generated from the gas generating agent by combustion into the airbag to protect an occupant from an impact. In the generator, the fixing means includes a cylindrical holder for gripping the igniter, a male screw engraved on an outer peripheral portion of the holder, a flange formed on a rear end of the holder, and an engraving on the housing. A female screw provided with the male screw, and an engaging portion formed at a predetermined position in the axial direction of the housing and engaged with the flange portion, wherein the flange portion has a central angle having a predetermined radial width of 90 degrees. An engaging surface extending axially at the front end of the plane with respect to the direction of rotation of the holder and having a length of one-fourth of the pitch of the screw; and an opposite side of the engaging surface from the front end. And an inclined surface ending at the rear end of the plane with an inclination angle corresponding to the lead angle of the screw from one end as a starting point, wherein the engaging portion is at a predetermined position in the axial direction of the housing and is perpendicular to the axial direction. A flat surface and an arc-shaped groove having a central angle of 90 ° formed in the flat surface. The groove has a width and a depth at which the flange portion can be fitted, and at a front end of the groove. It is characterized in that the flange portion has a stopper surface with which the engaging surface comes into contact.

The cylindrical holder holds the igniter. This holder is fixed to the housing by screw means. The holder advances by one pitch for each rotation by the screw means, and moves forward until the flange formed at the rear end of the holder reaches the plane of the engaging portion formed on the housing. This plane is at a predetermined position in the axial direction of the housing, and further rotation of the holder is prevented by this plane. However, a groove is formed in this plane, and the flange of the holder fits into this groove, and the rotation of the holder is further performed. Is possible. The rotation of the holder is stopped by the engagement surface of the flange portion abutting the stopper surface of the engagement portion. In this manner, the holder is positioned in the axial direction by the flange portion reaching the plane of the engagement portion, and is positioned in the circumferential direction by the groove and the stopper surface formed in this plane, and the ignition is performed. The container is positioned and fixed axially and circumferentially with respect to the housing via the holder.

[0007]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a half sectional view of a gas generator having the igniter fixing means of the present invention. The housing of the gas generator includes a diffuser shell 1 and a closure shell 3. The diffuser shell 1 and the closure shell 3 have circular portions 1c and 3c, and peripheral wall portions 1d and 3d formed on the outer periphery of the circular portion, respectively. The diffuser shell 1 includes a central tubular body 1a formed integrally with the circular portion at the central portion of the circular portion 1c. The center tubular body 1a has a tip extending to the outer surface position of the closure shell 3. Also, the closure shell 3 is
The central tubular body 1a has a hole 3a in which it can be fitted. On the inner peripheral portion of the central cylindrical body 1a, a female screw 21 with which a male screw 20 of a holder to be described later is screwed is formed.

The igniter, that is, the squib 10 is the holder 1
8. The holder 18 is a cylindrical hollow member, and includes a first holder 18a and a second holder 18b.
Consists of In the first holder 18a, a male screw 20 screwed into a female screw 21 is engraved on the outer circumference, and the inner circumference is
It is formed in a shape that conforms to the external shape of. The squib also holds the inner periphery of the second holder 18b and is formed into a shape conforming to the outer shape of the squib. This first holder 1
A flange portion 30 is formed at the rear end of 8a. The flange portion 30 includes an arc-shaped flat surface 30a having a predetermined radial width l and having a central angle O of 90 ° and a rotation direction A of the holder.
Engagement surface 30b extending axially at the front end 31 of the plane 30a and having a length d of a quarter of the pitch of the screw
And an inclined surface 30c starting from one end of the engagement surface 30b opposite to the front end and ending at the rear end 32 of the plane with an inclination angle corresponding to the lead angle β of the screw. The front end 31 of the flange is at the point 33 where the full thread of the male thread 20 begins.

A plane 22 perpendicular to the axial direction is formed at a predetermined position in the axial direction of the central cylindrical body 1a, and a groove 40 with which the flange portion 30 of the holder is engaged is formed in this plane 22. The groove 40 is an arc-shaped groove having a central angle O ′ of 90 °. This groove has a radial width in which the flange portion 30 can be fitted. The groove is inclined along the inclined surface 30c of the flange portion from the rear end 42 of the groove as a starting point, and the front end 4
A bottom surface 40b ending at 1 is provided. The bottom surface may be horizontal, as long as it has a depth at which the flange portion 30 can be fitted. Further, at the front end 41 of the groove, there is provided an axial stopper surface 40a with which the engaging surface 30b of the flange portion abuts. The rear end 42 of the groove is at the point 43 where the complete thread of the female thread 21 begins.

When attaching the holder 18 to the housing,
First, the squib 10 is engaged with the first holder 18a, and then the second holder 18b is engaged with the first holder 18a to grip the squib 10. Engagement with the male screw 20 starts at a point 43 where the complete screw portion of the female screw 21 starts. The point 33 where the complete thread portion of the male screw 20 starts
There is a front end 31 of the flange portion and a rear end 42 of the groove at a point 43 where the complete thread portion of the female thread 21 starts. The engaging surface 30b formed on the front end 31 of the flange portion advances by one pitch (p) for each rotation, and is at the position of the point 43 (the rear end position of the groove). Holder is n when n rotations
After moving by p, one end 34 of the engagement surface reaches the flat surface 22 (dashed line in FIG. 6). Further, when the flange portion 30 rotates by 90 °, the one end 34 of the engagement surface advances by a quarter pitch in the axial direction, and the engagement surface 30b moves by 90 ° in the circumferential direction to be in contact with the groove stopper surface 40a. Abut In this way,
The holder is always positioned and fixed at predetermined positions in the axial and circumferential directions with respect to the housing.

The inside 2 of the housing is defined in the circumferential direction by a central cylindrical body 1 a, an ignition device accommodating chamber 4 is provided inside the central cylindrical body, and a combustion chamber 5 and a coolant chamber 24 are provided outside thereof by a combustion ring 23. Further, a filter chamber 19 is formed surrounding the combustion chamber 5.

An opening 7 for transmitting the flame of the transfer charge 6 to the combustion chamber 5 is provided between the ignition device accommodating chamber 4 and the combustion chamber 5, and a combustion chamber is provided between the combustion chamber 5 and the coolant chamber 24. 5
An opening 8 for introducing the gas generated in the above is provided, the coolant chamber 24 and the filter chamber 19 are communicated with each other by an opening (not shown), and the coolant and the air bag (not shown) An opening for introducing gas that has passed through the filter, that is, a jet port 9 is provided.

When a sensor (not shown) is actuated by an impact, an electric signal is sent to the squib's priming and the priming is ignited, whereby the transfer charge 6 is ignited. The high-pressure, high-temperature flame generated thereby passes through the opening 7 and ignites the gas generating agent in the combustion chamber 5. The gas generated in the combustion chamber 5 passes through the opening 8, passes through the coolant 12 and the filter 13, and flows into the airbag through the ejection port 9.

[0015]

Since the present invention is constructed as described above, the axial and circumferential positioning of the igniter with respect to the housing can be performed simultaneously, and the igniter can be fixed at that position. Therefore, the mounting of the igniter becomes easy, and it is safe in operation and can be performed in a short time.

[Brief description of the drawings]

FIG. 1 is a half sectional view of a gas generator having a fixing means of an igniter of the present invention.

FIG. 2 is a plan view of a holder.

FIG. 3 is a plan view of an engagement portion formed in a central tubular body.

FIG. 4 is a perspective view of a holder.

FIG. 5 is a perspective view of an engaging portion of the central tubular body cut along line BB in FIG. 1;

FIG. 6 is a schematic diagram showing a state of engagement.

[Explanation of symbols]

 Reference Signs List 1 diffuser shell 3 closure shell 9 spout (opening) 10 squib (igniter) 18 holder 20 male screw 21 female screw 22 plane 30 flange section 30a plane 30b engagement surface 30c inclined surface 40 groove (engagement portion) 40a stopper surface 40b bottom surface

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B60R 21/16-21/32

Claims (1)

(57) [Claims] 1. A housing, a gas generating agent disposed in the housing, fixing means for fixing an igniter for burning the gas generating agent to the housing, and communication between the housing and the airbag. A gas generator having an opening for introducing the gas generated from the gas generating agent by combustion into an airbag to protect an occupant from an impact, wherein the fixing means has a cylindrical holder for gripping an igniter. When,
A male screw engraved on the outer periphery of the holder, a flange formed on the rear end of the holder, a female screw engraved on the housing and screwed with the male screw, formed at a predetermined position in the axial direction of the housing. The flange portion includes an engaging portion to be engaged, wherein the flange portion has an arc-shaped plane having a predetermined radial width and a central angle of 90 °, and an axial direction at a front end of the plane with respect to the rotation direction of the holder. One-fourth of the pitch of the extended screw
And an inclined surface ending at the rear end of the plane with an inclined angle corresponding to the lead angle of the screw starting from one end of the engaging surface opposite to the front end. The engaging portion has a plane located at a predetermined position in the axial direction of the housing and perpendicular to the axial direction, and a central angle formed on the plane is 9 mm.
0 °, the groove has a width and a depth at which the flange portion can be fitted, and a stopper surface with which the engaging surface of the flange portion abuts at the front end of the groove. A fixing means for an igniter in a gas generator for an air bag, comprising: