JPH08282424A - Gas generator for air bag having detonator mounting structure - Google Patents

Abstract

PURPOSE: To facilite pressure fitting of a detonator piece by providing a space, whose one end is in contact with a sensor accommodation chamber of a gas generator and other end with a fuse chamber, between the sensor accommodation chamber and the fuse chamber, and furnishing the detonator piece in this space. CONSTITUTION: The housing of a gas generator is formed from a diffuser shell 1 and a closure shell 3, and a sensor accommodation chamber 14 is partitioned inside the inner cylindrical part of a fuel 1, and the space 20 between the sensor accommodation chamber 14 and fuse chamber 17 is used to accommodate a detonator piece 21. One end of this space 20 is in contact with the sensor accommodation chamber 14 while the other end is in contact with the fuse chamber 17, and the detonator piece 21 to hold a detonator 11 is accommodated in the space 20. The piece 21 is a disc-shaped member, and a projection 21a provided in its center is fitted in the fuse chamber 17. A hole 21b is bored in a specified position of the piece 21, and the detonator 11 is loaded in the hole 21b. This facilitates manufacture of the gas generator and allows suppression of the costs.

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 mounting structure of a detonator in a mechanical ignition type gas generator.

[0002]

2. Description of the Related Art There are two types of gas generators, an electric ignition type and a mechanical ignition type, and an electric ignition type gas generator activates an igniter (squib) by heat generation of an electric current to ignite a transfer charge. In contrast, the mechanical ignition type gas generator has a detonator operated by a pure mechanical sensor,
Its advantage is that it does not require electric wiring and the like and is low in cost.

In the conventional mechanical ignition type gas generator,
A mechanical sensor is arranged in the sensor accommodating chamber in the housing, and the detonator is directly attached to the wall of the sensor accommodating chamber by caulking or the like.

[0004]

Since the above-mentioned sensor accommodating chamber is narrow and the place where the detonator is mounted is deep, the mounting is not easy. In addition, there is a risk that the detonator may be erroneously impacted at the time of mounting, and thus the transfer charge or the gas generating agent may be burned.

In order to solve the above problems, the applicant of the present invention has proposed an "airbag gas generator having a detonator mounting structure" in which detonator mounting is easy and safe (Japanese Patent Application No. 4- 23722).

According to the gas generator proposed above, press fitting is adopted as one of the fixing means for fixing the detonator piece in the space. That is, as shown in the cross-sectional view of the main part in FIG.
The outer diameter of the detonator piece 30 is formed to be slightly larger than the inner diameter of the wall 31 forming a space, so that a press-fitting surface 32 is formed between the outer peripheral surface of the detonator piece and the inner peripheral surface of the wall 31, thus The detonator piece is press-fitted and fixed in the space.

In this case, since both the outer peripheral surface of the detonator piece and the inner peripheral surface of the space wall have high rigidity, a large force is required for press-fitting without high dimensional accuracy, and press-fitting becomes difficult. There is a risk. High dimensional accuracy results in increased manufacturing costs.

Therefore, it is an object of the present invention to provide a novel gas generator that solves the above problems of the prior art.

[0009]

A gas generator for an air bag having a detonator mounting structure of the present invention comprises a housing,
A sensor accommodating chamber disposed in the housing and accommodating a mechanical sensor, a transfer charge chamber containing a transfer charge ignited by a detonator operated by the mechanical sensor, and a gas generating agent ignited by the transfer charge In a gas generator that has a combustion chamber that accommodates a housing, an opening that communicates the housing and an airbag, and introduces gas generated in the combustion chamber due to impact into the airbag to protect an occupant from the impact, The generator has a space between the sensor housing chamber and the transfer charge chamber, one end of which is in contact with the sensor storage chamber and the other end of which is in contact with the transfer charge chamber; A detonator piece having a hole for loading a detonator, wherein the detonator piece has a circumferential groove on an outer peripheral portion of an end face, and the detonator piece holding the detonator in the space is press-fitted. Is characterized by.

In the present gas generator, the detonator piece has a circumferential groove on the outer peripheral portion of the end face. This groove acts to appropriately reduce the rigidity of the detonator piece. Therefore, the detonator piece can be easily press-fitted without high dimensional accuracy. Radial position of the groove on the end face of the detonator piece,
The rigidity of the detonator piece can be made appropriate by changing the depth of the groove and the depth of the groove. This groove may be a continuous groove or an intermittent groove.

In this gas generator, since the detonator piece is formed separately, the detonator can be attached to the detonator piece separated from the gas generator body. Therefore, the mounting is facilitated, and since the mounting can be performed away from the transfer charge or the gas generating agent, the detonator can be mounted safely. The detonator piece with the detonator attached is attached to the gas generator body by press fitting. In this way, the detonator can be safely and easily loaded into the gas generator.

[0012]

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 sectional view of the present gas generator. The housing in this gas generator comprises a diffuser shell 1 and a closure shell 3. The diffuser shell 1 has a peripheral wall portion 1c and a flange portion 1a which is integrally formed at the tip of the peripheral wall portion 1c and extends in the radial direction. Further, the diffuser shell 1 has a circular portion 1b and an inner cylindrical portion 1d formed concentrically with the peripheral wall portion 1c at the center of the circular portion.

The closure shell 3 has an annular portion 3a, a peripheral wall portion 3b formed on the outer peripheral portion of the annular portion 3a, and a central hole 3c into which the inner cylindrical portion 1d of the diffuser shell fits. A circumferential projection 1e is integrally formed on the lower surface of the flange portion 1a of the diffuser shell, and a tip end portion of a peripheral wall portion 3b of the closure shell is fitted inside the circumferential projection 1e. In this way, the closure shell 3 is made into a diffuser. A void 2 is formed with the shell 1.

The space 2 is circumferentially delimited by the inner cylindrical portion 1d, and the sensor accommodating chamber 14 is demarcated inside the inner cylindrical portion.
A recess, that is, a transfer charge chamber 17 is formed in the circular portion 1b of the diffuser shell in the upper part of the sensor housing chamber 14. Further, a combustion chamber 5 is defined on the outer side of the inner cylindrical portion by a combustion ring 18, and a coolant / filter chamber 19 is formed so as to surround the combustion chamber 5.

A mechanical sensor 4 is accommodated in the sensor accommodating chamber 14, a transfer charge 6 is accommodated in the transfer charge chamber 17, and an annular canister container 10 is disposed in the combustion chamber 5. There is. This canister container 10 is a thin-walled container made of aluminum and is filled with a gas generating agent 15 inside. Further, the inside of the coolant / filter chamber 19 is demarcated by a retainer 16 into upper and lower stages, and the filter 12 is accommodated in the upper stage and the coolant 13 is accommodated in the lower stage.

A passage 7 for transmitting the flame of the transfer charge 6 to the combustion chamber 5 is provided between the transfer charge chamber 17 and the combustion chamber 5,
A plurality of openings 8 for introducing the gas generated in the combustion chamber 5 are provided in the circumferential direction between the combustion chamber 5 and the coolant / filter chamber 19.
A plurality of outlets 9 for introducing the coolant and the gas that has passed through the filter are provided in the circumferential direction between the air bag 9 and the airbag (not shown).

The gas generator comprises a detonator piece 21 for holding the detonator 11. The detonator piece 21 is a disk-shaped member, and has a protrusion 21a at the center thereof.
1a is fitted in the transfer charge chamber 17. Further, a hole 21b is formed at a predetermined position of the detonator piece 21, and the detonator 11 is loaded in the hole 21b. Detonator piece 21
Is configured as a separate body, so that the detonator piece can be separated from the housing, and the detonator piece can be set on the detonator piece in the separated state.

An accommodation space 20 for accommodating the detonator piece 21 is formed between the sensor accommodation chamber 14 and the transfer charge chamber 17. This space 20 has one end in contact with the sensor housing chamber 14 and the other end in contact with the transfer charge chamber 17.

A detonator piece 21 is housed in this space 20. 2, the detonator piece 21 has a circumferential groove 26 on the end face 25 on the transfer charge chamber 17 side.
have. The groove 26 is formed as a continuous groove on the outer peripheral portion of the end surface 25. Due to the presence of the groove 26, the tightening margin between the space 20 and the detonator piece 21 can be increased to some extent. That is, high dimensional accuracy is not required. Nevertheless, the detonator piece 21 is easily fixed in the space 20 by press fitting. FIG. 3 shows another embodiment of the detonator piece. This detonator piece has a circumferential groove 29 that is press-fitted into a circumferential projection 28 formed at the base of the diffuser shell inner tubular portion 1d. Further, it has a circumferential groove 27 continuous to the outside of the circumferential groove 29 in the radial direction. Due to the presence of the circumferential groove 29, the rigidity of the detonator piece is lowered to some extent, so that the width and the depth of the continuous groove 27 are made smaller than those of the groove 26 of FIG.

When mounting the detonator, prepare a detonator piece in which the detonator is set, first load the transfer charge 6 in the transfer charge chamber 17, then press fit the detonator piece 21 holding the detonator 11, and finally. The mechanical sensor 4 is housed in the sensor housing chamber 14, positioned, and fixed by the holding ring 23. An O-ring 24 is provided between the detonator piece 21 and the mechanical sensor 4 to protect the detonator 11 from moisture.

When the firing pin of the mechanical sensor 4 impacts the detonator 11 by the impact, the detonator 11 is ignited, and the transfer charge 6 is ignited. The high-pressure, high-temperature flame generated thereby passes through the passage 7 and breaks the wall of the canister container 10 to ignite the gas generating agent 15 inside. The gas generated in the combustion chamber 5 is uniformly ejected from the opening 8, the ejected gas passes through the coolant 13, the filter 12, and the exhaust port 9 into the airbag.

[0023]

As described above, according to the present invention, the detonator piece can be easily press-fitted, and the detonator piece and the space are not required to have high dimensional accuracy. Therefore, the manufacturing can be facilitated and the manufacturing cost can be reduced.

Further, according to the present invention, the detonator can be attached to the detonator piece separated from the gas generator main body,
Since the detonator piece with the detonator attached can be easily attached to the gas generator main body, the detonator can be easily attached, and this installation can be done away from the transfer charge or gas generant, ensuring safety. To be done.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of the present gas generator.

FIG. 2 is a cross-sectional view of a main part of a detonator piece included in the present gas generator.

FIG. 3 is a cross-sectional view of essential parts of another embodiment of the detonator piece provided in the present gas generator.

FIG. 4 is a cross-sectional view of essential parts of a detonator piece included in a conventional gas generator.

[Explanation of symbols] 1 Diffuser shell 3 Closure shell 4 Mechanical sensor 5 Combustion chamber 9 Discharge port 11 Detonator 14 Sensor housing chamber 17 Transfer charge chamber 20 Space 21 Detonator piece 26 Groove

Claims (1)

[Claims] 1. A housing, a sensor accommodating chamber arranged in the housing for accommodating a mechanical sensor, a transfer charge chamber for accommodating transfer charge ignited by a detonator operated by the mechanical sensor, It has a combustion chamber that contains a gas generating agent that is ignited by explosives, and an opening that connects the housing and the airbag, and introduces the gas generated in the combustion chamber into the airbag by impact to protect the occupant from the impact. In the gas generator, the gas generator includes a space between the sensor housing chamber and the transfer charge chamber, one end of which is in contact with the sensor storage chamber and the other end of which is in contact with the transfer charge chamber, and which is fitted into the space. And a detonator piece having a hole for loading a detonator on one end side,
The detonator piece has a groove in the circumferential direction on the outer peripheral portion of the end surface,
An air bag gas generator having a detonator mounting structure, wherein a detonator piece holding a detonator is press-fitted into the space.