JP2009292472A - Gas generator for airbag - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gas generator for an airbag which is easily manufactured with a simple structure, capable of reducing the manufacturing cost, changing the storage amount of a gas generating agent, and reliably igniting and burning the gas generating agent even by an ignition means of the regular output. <P>SOLUTION: A combustion chamber 5 for accommodating a gas generating agent 7 and a filter means accommodating chamber 6 for accommodating a cylindrical filter 15 are partitioned from each other by a partition member 10 having a plurality of through-holes 11 and curved in a projecting manner inward of the combustion chamber 5. A plurality of gas exhaust ports 4 are formed in a peripheral wall on which the filter means accommodating chamber 6 is mounted. The inside diameter of each of the plurality of through-holes 11 is smaller than the size of the gas generating agent 7, and the total area of opening parts of the plurality of through-holes 11 is larger than that of the plurality of gas exhaust ports 4. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a gas generator for an air bag suitably used for an inflatable safety system of a motor vehicle. More specifically, the present invention relates to a gas generator for an air bag characterized by the internal structure of a housing, and an air bag apparatus using the same. About.

  Airbag systems installed in various vehicles including automobiles support passengers with airbags (bags) that are rapidly inflated by gas when the vehicle collides at high speed. The purpose is to prevent injuries and the like by crashing into hard parts inside the vehicle such as the steering wheel and front glass. Such an airbag system is usually composed of a gas generator that is activated by a vehicle collision to release gas and an airbag that is inflated by introducing the gas.

  Like the gas generator for the driver's seat, passenger's seat, or side impact, this gas generator differs in the amount of generated gas required depending on the location (or application), and the entire housing. The shape is also different.

  Among these, as a gas generator arranged on the passenger seat side, conventionally, the housing shape is a cylindrical shape that is long in the axial direction, and the working gas for inflating the airbag generated in the housing is a peripheral wall. A plurality of gas discharge outlets are widely used.

  Further, the generation amount of the working gas for inflating the airbag is generally adjusted by the amount of gas generation means accommodated in the housing. In such a case, even if the amount of the gas generating means accommodated in the housing is somewhat different, if the same member can be used, the manufacturability can be improved and the manufacturing cost can be reduced.

  Furthermore, since the gas generating agent accommodated in the combustion chamber is ignited / combusted by the operation of the ignition means, depending on the shape of the combustion chamber, all the gas generating agent accommodated in the combustion chamber may be ignited / combusted. In some cases, a high output ignition means is required. For example, in the case of a cylindrical combustion chamber that is long in the axial direction, and the ignition means is disposed at the end in the axial direction, in order to burn the gas generating agent accommodated on the other end side by the ignition means Therefore, it is necessary to provide a high output ignition means capable of releasing a flame or the like to the end portion. However, such a high output ignition means is relatively expensive, which is not preferable from the viewpoint of reducing the manufacturing cost of the gas generator.

Japanese Patent Laid-Open No. 8-175312 European Patent Application Publication No. 888935 Japanese Patent Laid-Open No. 10-315897 Registered Utility Model No. 3015759 JP-A-9-220997 Japanese Patent Laid-Open No. 11-78763

Therefore, the present invention solves the above-described conventional problems, and has a simple structure, can be easily manufactured, and can reduce the manufacturing cost. Provided is a gas generator for an air bag that can reliably ignite and burn a gas generating agent even if it is a means.

  The gas generator for an air bag of the present invention is formed such that the combustion chamber in which the gas generating means is accommodated and the filter means accommodating chamber in which the filter means is accommodated are adjacent in the axial direction and communicated with each other in the housing. The combustion chamber and the filter means accommodation chamber are characterized by being partitioned by a partition member having a through hole. Thereby, even if it does not provide a moisture-proof means between both chambers, if the gas discharge port is closed, the moisture generation of the gas generating means is realized.

  That is, the gas generator for an air bag according to the present invention includes an ignition means that is activated by an impact and a gas generation means that is ignited and burned by the ignition means, in a cylindrical housing that is longer in the axial direction than in the radial direction. A gas generator for an air bag comprising: a combustion chamber for containing gas generating means and a filter means containing chamber for containing filter means, which are adjacent to and communicated with each other in the axial direction. The combustion chamber that accommodates the gas generating means is an air bag gas generator that is partitioned from the filter means accommodating chamber side by a partition member provided with a through hole.

  The partition member has a function of preventing the gas generating means accommodated in the combustion chamber from moving into the filter means accommodating chamber. However, this partition member does not have a function of adjusting the internal pressure in the combustion chamber communicating with the filter means accommodation chamber. The adjustment of the combustion pressure in the housing is adjusted exclusively by the opening area of the gas discharge port formed in the housing. Therefore, the partition member used for such a purpose has a through hole smaller than the gas generating means accommodated in the combustion chamber, and the total area of the opening is the total area of the opening of the gas discharge port. It is formed larger than. The total opening area of the partition member is preferably 1.5 times or more the total opening area of the gas discharge port. In the present specification, the total opening area of the partition member means the sum of the opening areas of all through holes formed in the partition member, and the total opening area of the gas discharge port is formed in the housing. This is the total opening area of the gas outlets.

  This partition member needs to have sufficient strength to withstand the internal pressure of the combustion chamber communicating with the filter means accommodation chamber (internal pressure of the combustion chamber during combustion of the gas generating means). In order to ensure such strength, for example, it may be formed in a curved shape so as to protrude toward the combustion chamber. The partition member formed in such a shape is not easily deformed by the combustion pressure of the gas generating means in the combustion chamber.

  Since the plurality of through holes formed in the partition member are not closed with a seal tape or the like, the combustion chamber and the filter means accommodation chamber are always in communication with each other. On the other hand, the cylindrical housing is formed with a gas outlet for introducing the working gas generated in the housing into an airbag (bag body). Therefore, for example, if this gas discharge port is closed with a seal tape or the like, the combustion chamber containing the gas generating means can be moisture-proof with the seal tape closing the gas discharge port. In this case, without providing a seal mechanism in the combustion chamber, it is possible to realize moisture prevention of the gas generating agent in the housing and the combustion chamber and rust prevention of the internal metal member. That is, by simplifying the sealing mechanism in the combustion chamber, a gas generator with a further reduced manufacturing cost is realized. Further, the amount of the working gas for inflating the airbag is usually adjusted according to the amount of the gas generating agent accommodated in the combustion chamber. Therefore, if the amount of the gas generating agent can be appropriately changed according to the amount of working gas required, the gas generator for an air bag can adjust the gas generation amount over a wide range with the same gas generator. Is realized. However, even if the amount of the gas generating agent is changed, it is necessary to reliably perform ignition and combustion by the ignition means, and it is desirable to prevent the gas generating agent from moving and preventing damage due to vibration.

  Therefore, in the present invention, an inwardly flanged plate member that supports the gas generating agent is disposed in the combustion chamber provided in the cylindrical housing, and the gas generating agent in the combustion chamber is pressed and / or pressed by this plate member. Alternatively, a gas generator for an airbag to be held is also provided. By disposing the plate member so as to be slidable in the axial direction of the housing, the amount of the gas generating agent accommodated can be adjusted. For example, the plate member can be formed so as to be fitted in the combustion chamber and function to press the gas generating means accommodated in the combustion chamber against the filter means accommodating chamber side, that is, the partition member side. Thereby, even when the amount of the gas generating agent accommodated is slightly changed, the gas generating agent in the combustion chamber is fixed by the plate member and the partition member, and damage due to vibration can be prevented.

  In the present invention, in order to obtain a gas generator that ignites and burns the gas generating agent reliably by the ignition means even if the amount of the gas generating agent is changed, a plurality of fire transmissions are provided in the combustion chamber and the peripheral wall. It is desirable to arrange a fire transfer tube in which holes are formed.

  That is, a gas generator for an air bag comprising an ignition means that operates by impact and a gas generation means that ignites and burns by the ignition means in a cylindrical housing that is longer in the axial direction than in the radial direction. In the housing, a combustion chamber for storing the gas generation means and a filter means storage chamber for storing the filter means are provided adjacent to each other in the axial direction. A fire transfer tube in which a heat transfer hole is formed is accommodated, and the heat transfer tube extends in the axial direction of the housing and has an end portion connected to an ignition means accommodation chamber in which the ignition means is accommodated. Gas generator for use.

  The heat transfer tube extends in the axial direction of the housing, and its end is connected to an ignition means accommodation chamber in which the ignition means is accommodated. Further, when the gas generating agent is supported by the plate member, the heat transfer tube can be formed so as to protrude into the accommodating space of the gas generating means through the central opening of the plate member. It is preferable that some or all of the plurality of heat transfer holes are in the accommodating space of the gas generating means. As a result, the flame generated by the operation of the ignition means passes through the heat transfer tube without being blocked by the plate member, and is jetted from the heat transfer hole into the combustion chamber to reliably ignite the gas generating agent in the combustion chamber.・ Can be burned.

  In particular, in the gas generator of the present invention, since the combustion chamber and the filter means are formed adjacent to each other in the axial direction of the housing, the distance in the length direction in the combustion chamber can be shortened. This can simplify the ignition means as compared with, for example, a gas generator in which a cylindrical filter is disposed in a housing and a combustion chamber is provided inside thereof. That is, when a combustion chamber is provided in the filter means, the combustion chamber is formed long in the axial direction. Therefore, in order to ignite and burn the gas generating agent accommodated at the end of the combustion chamber, the ignition means It becomes a complicated and expensive ignition system (igniting means) using an increase in the amount of the charge transfer composing the battery or using an explosion line or the like. However, if the combustion chamber and the filter means accommodation chamber are arranged in this way, the distance in the length direction of the combustion chamber can be shortened, and the gas generating means can be ignited and burned even by a normal ignition means. Can do.

The cylindrical housing that forms the outer container of the gas generator can be composed of a cylindrical diffuser shell having a plurality of gas discharge ports on the peripheral wall and a closure shell that closes both end openings of the peripheral wall. The plurality of gas discharge ports formed in the peripheral wall of the diffuser shell are formed in a range in which a filter means accommodation chamber described later is provided. Further, the closure shell for closing the combustion chamber side opening of the diffuser shell can be composed of an annular portion and a cylindrical portion protruding outward in the axial direction of the housing, and the ignition means is accommodated inside the cylindrical portion. be able to. If the housing is configured in this manner, the diffuser shell only needs to form a gas discharge port on the peripheral wall of the metal straight tube, and the manufacturing cost can be reduced. Further, if the ignition means is accommodated in a cylindrical portion protruding outside the housing, a maximum space can be secured in the combustion chamber.

  Filter means for cooling the combustion gas generated by the combustion of the gas generating means can be arranged in the filter means accommodation chamber. This filter means is disposed in the housing for the purpose of cooling and / or purifying the combustion gas generated by the combustion of the gas generating means. For example, a filter for purifying the combustion gas conventionally used In addition to using a coolant that cools the generated combustion gas, it is also possible to use a compression-molded laminated wire mesh filter, etc., in which a wire mesh made of appropriate materials is formed into an annular laminate. This filter means can be formed as a double structure having different pressure losses on the inner side and the outer side, and can also have a protective function for the filter means on the inner side and a function for suppressing the swelling of the filter means on the outer side. . Moreover, it is not limited to a wire mesh formed using such a wire, but a tube formed using expanded metal can also be used as a filter means. The filter means can also suppress swelling by supporting the outer periphery with an outer layer made of a laminated wire mesh body, a porous cylindrical body, an annular belt body or the like.

  It is desirable that the filter means be disposed after ensuring a gap of a predetermined width with the inner peripheral surface of the housing. By forming a gap between the outer peripheral surface of the filter means and the inner peripheral surface of the housing, when the combustion gas passes through the filter means, the gas concentrates and passes through the portion near the gas discharge port in the filter means To achieve full use of the filter means.

  Therefore, in the present invention, in order to arrange the filter means while ensuring a gap between the inner peripheral surface of the housing, a cylindrical diffuser shell having a plurality of gas discharge ports on the peripheral wall and both end openings of the peripheral wall portion are closed. There is also provided a gas generator for supporting and fixing the filter means with a closure shell that forms a housing with the closure shell and closes the opening on the filter means accommodation chamber side. Such a gas generator includes, for example, an annular portion that connects the closure shell to the opening edge of the diffuser shell, a circular portion that projects from the annular portion toward the filter means accommodation chamber, and a projection that projects from the annular portion to the outside of the housing. The circular portion can be formed so as to abut and support the inner peripheral surface of the filter means. Further, on the combustion chamber side of the filter means, when a filter support member is provided in which the inner peripheral wall of the annular portion protrudes into the hollow portion of the filter means and the outer peripheral wall is fitted in the housing, the inside of the filter means support member is arranged. The inner peripheral surface of the filter means can be supported by the peripheral wall and the circular portion of the diffuser shell.

  Gas generation means accommodated in the combustion chamber includes inorganic azides that are widely used in the past, such as azide gas generators based on sodium azide (sodium azide), as well as non-azide gas generation that is not based on inorganic azides. Agents can be used. However, in consideration of safety, a non-azide gas generating agent is desirable.

  The above-described gas generator for an air bag is accommodated in a module case together with an air bag (bag body) that introduces a gas generated by the gas generator and inflates, thereby forming an air bag device. In this airbag device, the gas generator is operated in conjunction with the impact sensor detecting the impact, and the combustion gas is discharged from the gas discharge port of the housing. The combustion gas flows into the air bag, whereby the air bag breaks the module cover and inflates to form a cushion that absorbs an impact between a hard structure in the vehicle and the occupant.

  According to the present invention, the amount of the gas generating agent can be changed while the structure is simple and easy to manufacture, and the gas generating agent is reliably ignited and burned even by the normal output ignition means. It becomes the gas generator for airbags which can be made to do. In particular, by simplifying the sealing mechanism in the combustion chamber, a gas generator for an air bag with a reduced manufacturing cost is provided.

  Furthermore, in a gas generator including a structure in which a heat transfer tube and a plate member are combined, the amount of the gas generating agent accommodated in the combustion chamber can be changed as appropriate, so that the gas generator can be used for general purposes. A vessel is provided.

Sectional drawing in alignment with the length direction which shows one Embodiment of the gas generator for airbags of this invention. The block diagram of the airbag apparatus of this invention.

  Hereinafter, based on the embodiment shown in the drawings, the gas generator for an air bag of the present invention will be described. [Embodiment 1] FIG. 1 is a longitudinal sectional view showing a first embodiment of a gas generator for an air bag according to the present invention. In the gas generator shown in this embodiment, the combustion chamber and the filter means accommodation chamber are adjacent to and communicated with each other in the axial direction, and the gas generation means in the combustion chamber is supported by a plate member, and is further transmitted to the combustion chamber. This is a gas generator for an air bag in which a fire tube protrudes.

In this gas generator, a housing 3 is formed by coupling and integrating a cylindrical diffuser shell 1 having a gas discharge port 4 and a closure shell 2 that closes an end opening of the diffuser shell 1. In the housing 3, a combustion chamber 5 for accommodating the gas generating agent 7 and a filter means accommodating chamber 6 for accommodating the cylindrical filter means 15 are provided adjacent to each other in the axial direction.

The combustion chamber 5 formed at the end of the housing 3 is a filter means accommodation chamber 6 by a partition member.
It is partitioned. In the present embodiment, a baffle member 10 that is convexly curved toward the combustion chamber is used as the partition member. This baffle member 10 has a function of preventing the gas generating agent 7 from moving to the filter means accommodation chamber side 6, and in order to send the working gas generated by the combustion of the gas generating agent 7 to the filter means accommodation chamber 6, A plurality of through-holes 11 communicating with the combustion chamber 5 and the filter means accommodation chamber 6 are formed. In the present embodiment, since the through hole 11 is not blocked by the seal tape 17 or the like, the combustion chamber 5 and the filter means accommodation chamber 6 are always in communication. Further, moisture prevention of the gas generating agent 7 accommodated in the combustion chamber 5 and rust prevention of the internal metal member are performed only by sealing a plurality of gas discharge ports 4 formed on the peripheral wall of the cylindrical housing 3. Therefore, the sealing mechanism on the combustion chamber 5 side can be simplified. However, if the purpose is not necessarily to simplify the sealing mechanism, for example, a gas generator in which the combustion chamber is partitioned from the filter means housing chamber by a baffle member, a gas generator that presses and holds a gas generating agent by a plate member, and / or In a gas generator with a heat transfer tube protruding into the combustion chamber, the through hole of this baffle member can naturally be closed with a sealing tape that bursts when the gas generating agent burns. The chamber and the filter means accommodation chamber are formed so as to communicate with each other. That is, in the present invention, the combustion chamber and the filter means accommodation chamber may always be in communication with each other as necessary, or may be formed to be in communication with each other by the combustion of the gas generating agent.

The combustion chamber 5 contains a porous cylindrical gas generating agent 7, and this gas generating agent 7 is supported between the plate member 18 having an inward flange shape and the baffle member 10. As a result, the movement of the gas generating agent 7 is prevented, and a situation where the gas generating agent 7 is damaged due to vibrations can be avoided. In the present embodiment, the plate member 18 has a peripheral wall portion 19 fitted in the combustion chamber 5 and supports the gas generating agent 7 with a flange portion 20 connected to the peripheral wall portion 19. Since the plate member 18 can slide in the axial direction of the housing 3, the movement of the gas generating agent 7 can be surely prevented even when the amount of the gas generating agent 7 is changed.

  The baffle member 10 having the through hole 11 supports the gas generating agent 7 housed in the combustion chamber 5 and prevents movement into the filter means housing chamber 6. The baffle member does not have a function of adjusting the combustion internal pressure in the first combustion chamber 5. Accordingly, the through hole 11 is adjusted so that its inner diameter is smaller than that of the first gas generating agent 7 and its total opening area is larger than the total opening area of the gas discharge port 4.

The diffuser shell 1 constituting a part of the housing 3 is formed using a cylindrical straight tube, and a plurality of gas discharge ports 4 are formed on a peripheral wall in a range where the filter means accommodation chamber 6 is provided. Yes. The gas discharge port 4 is closed with a seal tape 17 made of aluminum for the purpose of moisture prevention. Further, the gas discharge port 4 has a function of adjusting the internal pressure of the housing 3 at the time of combustion of the gas generating agent 7, and the total opening area of the gas generating agent 7 contained in each combustion chamber 5 is It is determined based on characteristics and the like.

A closure shell 2a for closing the opening on the filter means housing chamber 6 side of the diffuser shell 1 includes an annular portion 21 connected to the opening edge of the diffuser shell 1, and a circular portion 22 protruding from the annular portion 21 toward the filter means housing chamber 6 side. And a threaded portion 23 projecting outward from the annular portion 21 in the axial direction of the housing 3. The circular portion 22 is adjusted to a size capable of contacting the inner peripheral surface of the filter means 15 and plays a role of supporting the filter means 15. By combining a nut (not shown) with the screw portion 23, the gas generator can be attached to the module case.

On the other hand, the closure shell 2b that closes the opening of the diffuser shell 1 on the combustion chamber 5 side is integrally connected to the annular opening 21b connected to the opening end of the diffuser shell 1 and the central opening of the annular portion 21b. It is comprised with the cylindrical part 24 which protrudes in the direction outer side. This cylindrical part 24
In the internal space, an ignition means including an igniter 13 accommodated in a collar of the igniter 13 and a transfer agent 14 ignited and burned by the igniter 13 is accommodated. Since the peripheral edge of the annular portion 21b is formed so as to protrude outward in the radial direction of the diffuser shell 1, it can function as a flange portion when the gas generator is attached to the module.

The cylindrical portion of the closure shell 2 is closed with a cap member 25 connected to the end of the heat transfer tube 8. The heat transfer tube 8 connected to the cap member 25 has a plurality of heat transfer holes 9 formed in the peripheral wall, and the internal space communicates with the inside of the cylindrical portion 24 of the closure shell 2, that is, the space in which the ignition means is accommodated. is doing. This heat transfer tube 8 protrudes into the combustion chamber 5 through the central opening of the inward flange-shaped plate member 18 that supports the gas generating agent 7, and the heat transfer holes 9 formed in the peripheral wall thereof are It is formed so as to exist in the combustion chamber 5. As a result, the flame generated by the operation of the ignition means is ejected from the heat transfer hole 9 into the combustion chamber 5 through the heat transfer tube 8. Further, the plate member 18 is fitted in the housing 3 and is slidable in the length direction of the housing 3. However, the plate member 18 is adapted to the plate according to the amount of the gas generating agent 7 accommodated in the combustion chamber 5. Even when the position of the member 18 is changed, the gas generating agent 7 can be reliably ignited and burned by the flame ejected from the heat transfer hole 9. In the present embodiment, the heat transfer tube 8 has a stopper 29 on the tip side (that is, the filter means accommodation chamber 6 side) with respect to the portion where the heat transfer holes are formed.
It is blocked by. This stopper 29 blocks the internal space of the heat transfer tube 8 in a range not related to the heat transfer hole 9, thereby eliminating the useless space when the transfer charge is ignited and increasing the pressure in the space in which the ignition means is accommodated. It fulfills the function of improving the ignitability of the explosive 14 by.

A cylindrical filter means 15 is accommodated in the filter means accommodation chamber 6. In the present embodiment, the one formed by winding expanded metal in multiple layers is used. In addition, as the filter means 15, it is also possible to use a coolant / filter formed using a laminated wire mesh body and having both a cooling effect of the combustion gas and a function of collecting the combustion residual. The filter means 15 has its combustion chamber 5 side end supported by the filter means support member 12.
The other end is supported and fixed by the circular portion 22 of the closure shell 2b that closes the opening on the filter means accommodation chamber 6 side. Thus, the filter means 15 has a gap 16 having a predetermined width between the outer peripheral surface and the housing inner peripheral surface. In the present embodiment, the filter means support member 12 includes an inner peripheral wall 26 fitted into the central opening of the filter means 15, and an outer circumference extending to the opposite side of the inner peripheral wall and fitted into the inner peripheral surface of the housing 3. The wall 27 and an annular portion 28 that connects the inner peripheral wall and the outer peripheral wall are configured. The filter means support member 12 is fixed in the housing 3 by an embossing structure provided in the housing 3 or press fitting. The gap 16 secured between the outer peripheral surface of the filter means 15 and the inner peripheral surface of the housing 3 functions as a gas flow path,
When the combustion gas passes through the filter means 15, a situation where the combustion gas is concentrated in the vicinity of the gas discharge port 4 is avoided.

In the operation of the gas generator, when the igniter 13 is operated and the transfer charge 14 is ignited and burned, the flame passes through the transfer tube 8 and is ejected from the transfer hole 9 into the combustion chamber 5. As a result, the gas generating agent 7 in the combustion chamber 5 is ignited and burned to generate a working gas, and this gas flows into the filter means accommodation chamber 6 through the through hole 11 of the baffle member 10. Thereafter, the working gas is purified and cooled while passing through the filter means 15, and is released from the gas discharge port 4 by breaking the seal tape 17 that closes the gas discharge port 4.
[Embodiment 2] FIG. 2 shows an embodiment of an airbag apparatus according to the present invention in which a gas generator using an electric ignition type ignition means is included.

  The airbag device includes a gas generator 200, an impact sensor 201, a control unit 202, a module case 203, and an airbag 204. As the gas generator 200, the gas generator described with reference to FIG. 1 is used, and its operation performance is adjusted so as not to give a shock to the occupant as much as possible in the initial stage of the gas generator operation. ing.

The impact sensor 201 can be composed of, for example, a semiconductor acceleration sensor. In this semiconductor type acceleration sensor, four semiconductor strain gauges are formed on a beam of a silicon substrate which is bent when acceleration is applied, and these semiconductor strain gauges are bridge-connected. When acceleration is applied, the beam bends and the surface is distorted. Due to this strain, the resistance of the semiconductor strain gauge changes, and the change in resistance is detected as a voltage signal proportional to the acceleration.

The control unit 202 includes an ignition determination circuit, and a signal from the semiconductor acceleration sensor is input to the ignition determination circuit. When the impact signal from the sensor 201 exceeds a certain value, the control unit 202 starts computation, and when the computed result exceeds a certain value, an operation signal is output to the igniter 13 of the gas generator 200.

The module case 203 is made of polyurethane, for example, and includes a module cover 205. The airbag 204 and the gas generator 200 are accommodated in the module case 203 and configured as a pad module. This pad module is usually attached to the steering wheel 207 when attached to the driver's seat side of the automobile.

The airbag 204 is made of nylon (for example, nylon 66) or polyester, and the bag mouth 206 surrounds the gas outlet of the gas generator and is fixed to the flange portion of the gas generator in a folded state. .

When the semiconductor acceleration sensor 201 detects an impact at the time of a car collision, the signal is sent to the control unit 202, and when the impact signal from the sensor exceeds a certain value, the control unit 202 starts calculation. When the calculated result exceeds a certain value, an operation signal is output to the igniter 13 of the gas generator 200. As a result, the igniter 12 operates to ignite the gas generating agent, and the gas generating agent burns to generate gas. This gas is ejected into the air bag 204, whereby the air bag breaks the module cover 205 and inflates to form a cushion that absorbs impact between the steering wheel 207 and the occupant.

DESCRIPTION OF SYMBOLS 1 Diffuser shell 2 Closure shell 3 Housing 4 Gas discharge port 5 Combustion chamber 6 Filter means accommodation chamber 7 Gas generating agent 8 Fire transfer tube 10 Baffle member 12 Filter means support member 13 Igniter 15 Filter means 17 Seal tape 18 Plate member

Claims (9)

A gas generator for an air bag comprising an ignition means that is activated by an impact and a gas generating agent that is ignited and burned by the ignition means in a cylindrical housing that is longer in the axial direction than in the radial direction. ,
In the cylindrical housing, a combustion chamber for storing the gas generating agent and a filter means storage chamber for storing the cylindrical filter means are provided adjacent to and in communication in the axial direction,
The combustion chamber that stores the gas generating agent is partitioned from the filter means storage chamber side by a partition member that has a plurality of through holes and is curved in a convex shape inside the combustion chamber.
In the combustion chamber, a plate member is further fitted in the combustion chamber so as to be slidable in the axial direction of the cylindrical housing,
A gas generating agent accommodated in the combustion chamber is supported between the partition member and the plate member;
A plurality of gas discharge ports are formed on the peripheral wall of the tubular housing in a range where the filter means accommodation chamber is provided,
The inner diameters of the plurality of through holes are smaller than the gas generating agent,
A gas generator for an airbag, wherein a total area of the openings of the plurality of through holes is adjusted to be larger than a total area of the openings of the plurality of gas discharge ports.   The gas generator for an air bag according to claim 1, wherein the total area of the openings of the plurality of through holes is adjusted to be 1.5 times or more of the total area of the openings of the plurality of gas discharge ports.   The gas generation for an air bag according to claim 1 or 2, wherein the cylindrical housing is provided with a plurality of gas discharge ports on a peripheral wall thereof, and the housing is moisture-proof by a sealing tape for closing the gas discharge ports. vessel.   The gas generator for an air bag according to any one of claims 1 to 3, wherein the plate member has an inward flange shape.   The combustion chamber contains a heat transfer tube having a plurality of heat transfer holes formed in the peripheral wall. The heat transfer tube extends in the axial direction of the housing, and an end thereof is accommodated by an ignition means. The gas generator for airbags as described in any one of Claims 1-4 connected with the made ignition means accommodation chamber.   The cylindrical housing includes a cylindrical diffuser shell having a plurality of gas discharge ports on a peripheral wall, and a closure shell that closes both ends of the peripheral wall, and closes an opening on the combustion chamber side. Is composed of an annular part connected to the opening edge of the diffuser shell and a cylindrical part projecting to the outside of the housing, and ignition means is accommodated inside the cylindrical part. The gas generator for airbags as described in any one of Claims 1-3.   The cylindrical housing is composed of a cylindrical diffuser shell having a plurality of gas discharge ports on the peripheral wall, and a closure shell that closes both end openings of the peripheral wall portion, and closes the opening on the filter means accommodation chamber side. The closure shell is composed of an annular portion connected to the opening edge of the diffuser shell, a circular portion projecting from the annular portion toward the filter means accommodation chamber, and a screw portion projecting from the annular portion to the outside of the housing. The gas generator for an air bag according to any one of claims 1 to 6, wherein the circular portion is in contact with an inner peripheral surface of the filter means to support the filter means. On the combustion chamber side of the filter means, a filter support member is disposed in which the inner peripheral wall of the annular portion protrudes into the hollow portion of the filter means, and the outer peripheral wall is fitted in the housing. The gas generator for an air bag according to claim 7, wherein the gas generator for an air bag is supported and fixed by an inner peripheral wall of the support member and a circular portion of the diffuser shell. A gas generator for an air bag;
An impact sensor that senses impact and activates the gas generator;
An airbag that inflates by introducing gas generated by the gas generator;
An air bag apparatus comprising: a module case for housing the air bag, wherein the air bag gas generator is the air bag gas generator according to any one of claims 1 to 8.

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