JPH05116585A - Gas producer for air bag - Google Patents

Abstract

PURPOSE:To enlarge the storage space of an air bag by forming the outer surface of a gas producer into a face having no protrusion. CONSTITUTION:An internal thread 17 is cut in the inner peripheral portion of a center cylindrical body 1a. A squib holder 18 is threadably engaged in the internal thread 17. The squib holder is for holding a squib ignitor 10 within the center cylindrical body 1a and comprises a first holder 18a and a second holder 18b. An external thread 20 for threadable engagement in the internal thread 17 is cut in the outer periphery of the first holder 18a and the inner periphery of the first holder 18a is so formed to fit with the outer shape of the squib 10. A conical plane fitting with the conical plane of the squib held by the holder is formed in the inner periphery of the second holder 18b and is made to abut on a positioning stepped portion 21 formed in the inner peripheral portion of the center cylindrical body and is engaged therein. The overall length of the squib holder is equal to the distance from the outer face 3e of a closure shell to the stepped portion 21 and the end face of the first holder 18a forms roughly the same plane as the outer face 3e of the closure shell.

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 airbag which protects an occupant from an impact, and more particularly to a structure of the gas generator capable of reducing the storage space of the airbag.

[0002]

2. Description of the Related Art As an example of the structure of a conventional gas generator,
There is one shown in FIG. Two outer shells, that is, a diffuser shell 31 and a closure shell 32 are joined by screws 33.

[0003]

In this case, a large-diameter screw head projects on the outer surface of the diffuser shell 31, which reduces the storage space for the airbag. Further, when the screw head projects toward the closure shell 32 side, it becomes difficult to attach the gas generator to the pad.

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

[0005]

A gas generator for an air bag according to the present invention comprises a housing comprising a first outer shell and a second outer shell, and a gas generator installed in the housing.
In a gas generator having an opening for communicating a housing and an air bag and introducing gas generated by the gas generating device into the air bag by an impact to protect an occupant from the impact, the first outer shell is A central tubular body having a length whose tip does not protrude from the outer surface of the second outer shell is provided in the central portion, and the second outer shell has an annular recess around a hole into which the central tubular body can be fitted. A screw member having one end surface abutting the bottom surface of the annular recess and the other end surface forming a plane substantially the same as the outer surface of the second outer shell is engraved on the outer peripheral portion of the central tubular body. While being screwed into the male screw, one end surface abuts on a positioning step formed on the inner peripheral portion of the central tubular body, and the other end surface is the second step.
The squib holder forming a plane substantially the same as the outer surface of the outer shell is screwed into the female screw engraved on the inner peripheral portion.

The first outer shell has a central tubular body in the central portion. The second outer shell has an annular recess around the hole into which the central tubular body can be fitted. A screw member is fitted in the annular recess and screwed into a male screw engraved on the outer peripheral portion of the central tubular body. One end surface of the screw member abuts the bottom surface of the annular recess to press the second outer shell against the first outer shell by the fastening action of the screw, and the other end surface of the screw member is the outer surface of the second outer shell. And a plane substantially the same as that of the second outer shell is formed so as not to project from the outer surface of the second outer shell. Further, the squib holder is screwed onto a female screw engraved on the inner peripheral portion of the central tubular body so as to hold the squib inside the central tubular body. This squib holder is
One end surface of the second tubular body is positioned by being brought into contact with a positioning step formed on the inner peripheral portion of the central tubular body, and the other end surface forms a plane substantially the same as the outer surface of the second outer shell. Does not protrude above the outer surface of the outer shell.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a half sectional view of the gas generator. The housing of the gas generator includes a first outer shell,
That is, it consists of the diffuser shell 1 and the second outer shell, that is, the closure shell 3. The diffuser shell 1 and the closure shell 3 respectively have circular portions 1c and 3c and peripheral wall portions 1d and 3d formed on the outer peripheral portion of the circular portions. The diffuser shell 1 has a circular portion 1c.
A central tubular body 1a integrally formed with the circular portion is provided at the central portion of the. The central tubular body 1a has its tip extending to the outer surface position of the closure shell 3. Further, the closure shell 3 includes an annular recess 3b around the hole 3a into which the central tubular body 1a can be fitted. The annular recess 3b has a bottom surface 3f at a position axially spaced from the outer surface 3e of the closure shell.

A male screw 15 is engraved on the outer peripheral portion of the central cylindrical body 1a. A screw member, that is, an adapter 16, is screwed onto the male screw 15. The adapter 16 comprises a small diameter portion and a large diameter portion having a predetermined outer diameter, the small diameter portion is fitted in the hole 3a, and the large diameter portion is fitted in the annular recess 3b. The large-diameter portion has a thickness corresponding to the distance from the outer surface 3e to the bottom surface 3f, one end surface of which contacts the bottom surface 3f of the annular recess, and the other end surface of which is the outer surface 3e of the closure shell 3.
And substantially the same plane is formed.

A female thread 17 is formed on the inner peripheral portion of the central cylindrical body 1a. A squib holder 18 is screwed onto the female screw 17. The squib holder is for holding the squib (igniter) 10 in the central cylindrical body 1a, and includes a first holder 18a and a second holder 18b. The first holder 18 a has a male screw 20 that is screwed into the female screw 17 and is engraved on the outer periphery, and the inner periphery is formed in a shape that matches the outer shape of the squib 10. The second holder 18b has a conical surface formed on the inner circumference that matches the conical surface of the squib to be held, and comes into contact with the positioning step portion 21 formed on the inner peripheral portion of the central tubular body. It is locked to the step. The entire length of the squib holder corresponds to the distance from the outer surface 3e of the closure shell to the step portion 21, and the first holder 1
The end surface of 8a forms a plane substantially the same as the outer surface 3e of the closure shell.

The diffuser shell 1 and the closure shell 3 are screwed together by an adapter 16 at the central portion and joined by welding 22 at the outer peripheral portion.
In this way, the strength is maintained against the internal pressure of the gas generator.

The inside 2 of the housing is circumferentially demarcated by a central tubular body 1a, the ignition device accommodating chamber 4 is provided inside the central tubular body, and the combustion chamber 5 and the coolant chamber 24 are provided outside by the combustion ring 23. Further, a filter chamber 19 is formed surrounding the combustion chamber 5.

A squib 10 and an enhancer (transfer charge) 6 are housed in the ignition device housing chamber 4, a gas generating agent (not shown) is filled in the combustion chamber 5, and a coolant chamber 24 is further housed in the coolant chamber 24. The coolant 12 and the filter 13 are housed in the filter chamber 19.

An opening 7 for transmitting the flame of the transfer charge 6 to the combustion chamber 5 is provided between the ignition device housing chamber 4 and the combustion chamber 5, and a combustion chamber is provided between the combustion chamber 5 and the coolant chamber 24. 5
The opening 8 for introducing the gas generated in 1. is provided, the coolant chamber 24 and the filter chamber 19 are communicated with each other by an opening (not shown), and the filter chamber 19 and the air bag (not shown) further have a coolant, An opening for introducing the gas that has passed through the filter, that is, an ejection port 9 is provided.

When a sensor (not shown) is actuated by the impact, the squib 10 is ignited, which ignites the transfer charge 6. The high-pressure, high-temperature flame generated thereby passes through the opening 7 and ignites the gas generating agent in the combustion chamber 5. Combustion chamber 5
The gas generated inside passes through the opening 8, the coolant 12,
It passes through the filter 13 and flows into the airbag through the ejection port 9.

[0016]

Since the present invention is configured as described above, the outer surface of the gas generator is formed into a surface without protrusions,
As a result, the storage space for the airbag can be increased. Moreover, when the gas generator is attached to the pad, the attachment becomes easy.

[Brief description of drawings]

FIG. 1 is a half sectional view of a gas generator of the present invention.

FIG. 2 is a schematic cross-sectional view showing the structure of a conventional gas generator.

[Explanation of symbols]

 1 Diffuser Shell (First Outer Shell) 1a Central Cylindrical Body 3 Closure Shell (Second Outer Shell) 3b Annular Recess 9 Outlet (Open) 10 Squib 15 Male Thread 16 Adapter (Screw Member) 17 Female Thread 18 Squib Holder 21 Step

Claims (1)

[Claims] 1. A housing comprising a first outer shell and a second outer shell, and a gas generator installed in the housing.
A gas generator that has an opening that connects a housing and an airbag, and introduces gas generated by the gas generation device into the airbag by an impact to protect an occupant from the impact, wherein the first outer shell is A central tubular body having a length whose tip does not protrude from the outer surface of the second outer shell is provided in the central portion, and the second outer shell has an annular recess around a hole into which the central tubular body can be fitted. A screw member having one end surface abutting the bottom surface of the annular recess and the other end surface forming a plane substantially the same as the outer surface of the second outer shell is engraved on the outer peripheral portion of the central tubular body. While being screwed into the male thread, one end surface of the central tubular body contacts a positioning step formed on the inner peripheral portion of the central cylindrical body, and the other end surface forms a plane substantially the same as the outer surface of the second outer shell. An air bag characterized in that the squib holder is screwed into a female screw engraved on the inner peripheral portion. Gas generator for gas.