JP2001206188A - Gas generator for air bag and air bag device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small-size and lightweight gas generator for an air bag manufacturable easily at a low cost. SOLUTION: This gas generator comprises an ignition means, a gas generating means, and a filter means contained in a housing comprising a diffuser shell and a closure shell, both having a flange part extending to the radial outside thereof. The flange part of the diffuser shell is connected to the flange part 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 an airbag gas generator for protecting an occupant from an impact and an airbag device.

[0002]

2. Description of the Related Art As a conventional gas generator for an air bag,
A housing comprising a diffuser shell formed by forging and having a circular portion integrally forming three concentric cylinders, and a closure shell similarly formed by forging and having a circular portion integrally forming a joint corresponding to the three concentric cylinders is provided. Some have. The innermost cylinder defines an ignition means receiving chamber, the outer cylinder defines a combustion chamber, and the outermost cylinder defines a coolant and filter chamber. An ignition means comprising an igniter and a transfer charge is disposed in the ignition means storage chamber, a gas generating agent which is ignited by the ignition means to generate gas is disposed in the combustion chamber, and a combustion filter is provided in the coolant / filter chamber. A coolant filter for cooling the gas and collecting the combustion residues is provided.

FIG. 8 shows a conventional gas generator for an air bag. This gas generator has a housing 103 composed of a diffuser shell 101 and a closure shell 102.
The outer periphery is reinforced by a large number of rivets 106, and the center is reinforced by screw members 104 and 105 screwed together.

A conventional gas generator for an air bag is disclosed in Japanese Utility Model Laid-Open No. 50-15652. This is shown in FIG. This gas generator includes an upper container 107, a lower container 108, and a fastening ring 109, and a joint 110 of the upper container 107 and a joint 111 of the lower container 108.
Are overlapped, and these joints are projected and fastened to the concave portions of the fastening ring 109.

[0005]

The forged product has a uniform metal structure and a high toughness, but has the disadvantage of a high cost. Further, when an outer shell member having a large number of concentric cylinders is formed by forging, the circular portion is not flattened, which requires cutting, which increases the number of manufacturing steps and increases the cost. Further, in the above-mentioned conventional gas generator, the diameter of the gas generator is enlarged due to the structure in which the coolant / filter chamber is defined outside the combustion chamber, and therefore, the size and weight of the gas generator are increased. The result is inviting. Further, in the above-mentioned conventional gas generator having three concentric cylinders, the shapes of the diffuser shell and the closure shell are complicated, which makes the production of the gas generator complicated and increases the cost.

Further, the conventional gas generator shown in FIG. 8 has a large number of rivets arranged in the circumferential direction of the housing and a screw member screwed together.
There are problems that the weight of the gas generator increases, the diameter of the gas generator increases, and the number of parts also increases.

Further, in the conventional gas generator shown in FIG. 9, the joints 110 and 111 formed in a curved shape are used.
In addition, there is a problem that the fastening ring 109 is formed in a concave shape, so that the fastening structure becomes complicated, and the weight of the gas generator increases and it is difficult to reduce the weight.

Accordingly, it is an object of the present invention to provide a novel gas generator for an airbag and an airbag device which solve the above-mentioned problems of the prior art.

[0009]

According to the present invention, there is provided an airbag gas generator according to the present invention, comprising a first circular portion having no machined hole and a plurality of peripheral portions formed on the outer periphery of the first circular portion. A diffuser shell having a peripheral wall portion having a gas discharge port, a flange portion extending radially outward at a distal end portion of the peripheral wall portion, a space formed together with the diffuser shell, a second circular portion, A central hole formed at the center of the second circular portion, a peripheral wall formed at the outer peripheral portion of the second circular portion, and a flange extending radially outward at a tip end of the peripheral wall. A housing composed of a closure shell, ignition means disposed in the center hole of the closure shell in the space, and ignition gas generated by the ignition means disposed in the space and surrounding the ignition means. Gas generating means, Filter means for housing the generating means therein and disposed inside the inner peripheral wall of the space for cooling the combustion gas and collecting combustion residues, wherein the flange portion of the diffuser shell and the closure shell It is characterized by being joined to a flange portion.

It is preferable that the diffuser shell and the closure shell are each formed by press-molding a plate.

It is preferable that the flange portion of the diffuser shell has a mounting portion for mounting a pad module to a mounting bracket.

Preferably, the flange portion of the diffuser shell and the flange portion of the closure shell are joined by welding.

[0013] It is preferable that a rib-like reinforcing member and / or a reinforcing step is formed on at least one of the first circular portion of the diffuser shell and the second circular portion of the closure shell. .

[0014] The central hole of the closure shell may have a bent portion in the axial direction for disposing the ignition means at an edge of the hole.

It is preferable that the flange portion of the diffuser shell and the flange portion of the closure shell are joined together at or near a position on the axial center cross section of the housing.

Each of the diffuser shell and the closure shell may be made of a metal plate having a thickness of 1.2 to 3.0 mm.

Preferably, the metal plate is any one of a stainless steel plate, a nickel-plated steel plate, and an aluminum alloy plate.

It is preferable that the diffuser shell and the closure shell each have an outer diameter of 45 to 75 mm.

Further, the height from the top surface of the diffuser shell to the bottom surface of the closure shell is 25 to 40 m.
m is preferable.

In the housing, there may be provided a central cylindrical member which is formed of a tube and is disposed concentrically with the central hole of the closure shell and forms a hollow chamber for the ignition means inside.

The airbag device of the present invention comprises the following.

That is, a gas generator according to claim 1;
An impact sensor that senses an impact and outputs a sensing signal, a control unit that inputs the sensing signal and outputs an operation signal to ignition means of the gas generator, and introduces and expands gas generated by the gas generator. And a module case accommodating the airbag.

It is preferable that each of the diffuser shell and the closure shell is formed by pressing a plate.

It is preferable that the flange portion of the diffuser shell has a mounting portion for mounting a pad module to a mounting bracket.

Preferably, the flange portion of the diffuser shell and the flange portion of the closure shell are joined by welding.

It is preferable that a rib-like reinforcing member and / or a reinforcing step are formed on both or one of the first circular portion of the diffuser shell and the second circular portion of the closure shell. .

[0027] The central hole of the closure shell is
It is preferable to have an axially bent portion for disposing the ignition means at the edge of the hole.

[0028] It is preferable that the flange portion of the diffuser shell and the flange portion of the closure shell are overlapped and joined at a position on or near a central cross section in the axial direction of the housing.

[0029] The diffuser shell and the closure shell may each be formed of a metal plate having a thickness of 1.2 to 3.0 mm.

Preferably, the metal plate is any one of a stainless steel plate, a nickel-plated steel plate, and an aluminum alloy plate.

Preferably, the diffuser shell and the closure shell each have an outer diameter of 45 to 75 mm.

The height from the top surface of the diffuser shell to the bottom surface of the closure shell is 25 to 40 m.
m is preferable.

In the gas generator of the present invention, the diffuser shell and the closure shell are both cylindrical and simple.
Since it has a simple shape, press molding is easy. Further, in this gas generator, the flange portions of the diffuser shell and the closure shell to be joined provide rigidity to the housing, particularly to the outer peripheral wall thereof. This prevents deformation of the housing due to gas pressure. Further, in this gas generator, the diffuser shell has a flange portion, and this flange portion is located below the mounting bracket for fixing the pad module including the gas generator. The risk of harm to the bag side, that is, the occupant side can be avoided. The diffuser shell and the closure shell can each be formed by pressing a plate, thereby facilitating the production of the diffuser shell and the closure shell, and at the same time reducing the production cost. Instead of press forming, the diffuser shell and the closure shell can be formed by casting using an aluminum alloy.

The rib-like reinforcing member and the reinforcing step provided on the circular portion of the diffuser shell and the closure shell impart rigidity to the housing, particularly to the circular portion. This prevents deformation of the housing due to gas pressure. Further, a rod body joined to the circular portions of the diffuser shell and the closure shell by welding or the like can be provided between the circular portions. Thereby, the deformation of the housing in the vertical direction is prevented.

The diffuser shell and the closure shell form a housing of the gas generator, and are made of a stainless steel plate having a thickness of 1.2 to 3.0 mm, respectively.
It preferably has an outer diameter of 75 mm. This outer diameter is
More preferably, it is 50 to 70 mm. The diffuser shell and the closure shell can be joined by various welding methods such as electron beam welding, laser welding, TIG welding, and projection welding. Regarding the material of the diffuser shell and the closure shell, nickel-plated steel plate may be used instead of stainless steel plate. Set the gas outlet of the diffuser shell to 1.5-4.
The diameter is 5 mm or 2 to 5 mm, and a total of 16 to 24 or 12 to 20 pieces can be arranged in the circumferential direction. In addition, the total height of the housing (height from the top surface of the diffuser shell to the bottom surface of the closure shell) is 25 to 40 mm.
It is preferable that

As a gas generating means used in the present gas generator, those based on inorganic azides, particularly those based on sodium azide, for example, an equivalent mixture of sodium azide and copper oxide, which have been widely used, may be used. It is more advantageous to use a non-azide gas generating agent in terms of safety and the like. Various non-azide gas generant compositions have been proposed. For example, those containing a nitrogen-containing organic compound such as tetrazole, triazole or a metal salt thereof and an oxygen-containing oxidizing agent such as an alkali metal nitrate as a main component, triaminoguanidine nitrate, carbohydrazide, nitroguanidine, etc. as fuel and nitrogen. As a source, a composition using an alkali metal or alkaline earth metal nitrate, chlorate, perchlorate or the like as an oxidizing agent is known, and any of them can be used as a gas generating agent in the present invention. However, the present invention is not limited to these, and is appropriately selected according to the requirements of the burning rate, non-toxicity and burning temperature. The gas generating agent is used in an appropriate shape such as a pellet, a wafer, a hollow cylinder, a porous body, or a disk.

The filter means can be formed by laminating flat knitted metal meshes in the radial direction and compressing them in the radial and axial directions. The filter means formed in this way has a complicated void structure and has an excellent trapping effect. Therefore, it is possible to realize a coolant / filter integrated filter unit having both a cooling function and a collecting function.
More specifically, a flat braided stainless steel wire mesh is formed in a cylindrical body, and one end of the cylindrical body is repeatedly bent outward to form an annular laminate, and the laminate is compression-molded in a mold. Thereby, the filter means can be formed.
Alternatively, a flat knit stainless steel wire mesh is formed in a cylindrical body, and the cylindrical body is pressed in the radial direction to form a plate, and the plate is wound into a cylindrical shape in multiple layers to form a laminate, The filter means can also be formed by compression molding this laminate in a mold. Stainless steel, which is the material of the wire mesh, is SUS304, SUS310S, SUS316.
(JIS standard symbol) can be used. SU
S304 (18Cr-8Ni-0.06C) exhibits excellent corrosion resistance as an austenitic stainless steel.

[0038] The filter means may also be of a double structure having a layer of laminated metal mesh inside or outside thereof. The inner layer may have a filter means protection function for protecting the filter means against the flame of the ignition means ejected toward the filter means and the combustion gas of the gas generating means ignited and burned by the flame. The outer layer also prevents swelling of the filter means so that the filter means does not swell due to gas pressure during operation of the gas generator and does not block the gap formed between the filter means and the outer peripheral wall of the housing. It can function as a deterrent.
The function of suppressing the swelling of the filter means can also be realized by supporting the outer periphery of the filter means with an outer layer made of a laminated metal mesh, a porous cylinder, an annular belt or the like.

The filter means has an outer diameter of 40 to 65 mm,
It can have an inner diameter of 30-55 mm and a height of 19-37.6 mm.

[0040]

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

FIG. 1 is a sectional view of a gas generator for an air bag according to the present invention. In this embodiment, the housing outer diameter is 7
It is effective as a gas generator of around 0 mm. The gas generator includes a housing 3 composed of a diffuser shell 1 and a closure shell 2 and ignition means provided in a housing space in the housing 3, that is, an igniter 4 and a transfer charge 5.
And gas generating means ignited thereby to generate combustion gas, that is, the solid gas generating agent 6, and filter means defining the combustion chamber 28 accommodating the gas generating agent 6, that is, the coolant filter 7. Contains.

The diffuser shell 1 is formed by pressing a stainless steel plate by pressing, and includes a first circular portion 12, a peripheral wall portion 10 formed on the outer peripheral portion of the circular portion 12, and a distal end portion of the peripheral wall portion 10. It has a flange portion 19 extending radially outward. In this embodiment, the peripheral wall 10 has a thickness of 3 mm.
Gas outlets 11 having a diameter of 18 are arranged at equal intervals in the circumferential direction. Regarding the arrangement of the gas discharge ports, although not shown in the drawings, they are formed in the circular portion 12 by being arranged in the circumferential direction, or formed in both the circular portion 12 and the peripheral wall portion 10. be able to. This diffuser shell 1
In the center of the circular portion 12, a projecting circular portion 13 protruding outward by a reinforcing step 49 is formed.
Provides rigidity to the housing, particularly to the circular portion 12 of the diffuser shell forming the ceiling thereof, and increases the volume of the accommodation space. A transfer charge container 53 containing the transfer charge 5 is sandwiched between the protruding circular portion 13 and the igniter 4. As shown in FIG. 2, the flange portion 19 of the diffuser shell is provided with a mounting portion 98 for mounting the pad module to the mounting bracket.
have. The mounting portion 98 is disposed at 90 ° intervals in the circumferential direction of the flange portion 19 and has a mounting hole 99 for a screw bolt. The outer shape of the flange portion 20 on the closure shell side is shown by a dotted line in FIG. Note that the shape of the flange may be formed so as to protrude in the radial direction at predetermined intervals (every 90 degrees in FIG. 11) as shown in FIG.

The closure shell 2 is formed by pressing a stainless steel plate by pressing, and has a second circular portion 30, a central hole 15 formed at the center thereof, and a peripheral wall formed at the outer peripheral portion of the circular portion 30. A portion 47 and a flange portion 20 extending radially outward at a distal end portion of the peripheral wall portion 47 are provided. The central hole 15 has an axial bent portion 14 at the edge of the hole. The bent portion 14 provides rigidity to the edge of the central hole 15 and provides a relatively large joint surface with the central cylindrical member 16. A central cylindrical member 16 is arranged to fit into the central hole 15, and an end surface 17 on one end side of the central cylindrical member 16 is flush with an end surface 18 of the bent portion 14.

In the diffuser shell 1 and the closure shell 2, the flange portion 19 of the diffuser shell and the flange portion 20 of the closure shell are placed close to each other in the vicinity of a position on the axial center cross section of the housing 3, and the laser welding 2 is performed.
The two are joined to form a housing 3. These flange portions 19 and 20 provide rigidity to the housing, particularly to the outer peripheral wall 8 thereof, and prevent deformation of the housing due to gas pressure.

The central cylindrical member 16 is formed of a stainless steel tube having both ends opened, and the other end is fixed to the projecting circular portion 13 of the diffuser shell by electron beam welding 22. When the inner cylindrical member 16 is fixed to the projecting circular portion 13 by beam welding 22, the projecting circular portion 1
3 is deformed, and the degree of the deformation is almost the same. Therefore, the diffuser shell is processed into a shape in consideration of the amount of the deformation in advance, and the inner cylindrical member 16 is welded to obtain a desired shape. Can also be formed. An ignition means accommodating chamber 23 is formed inside the central tubular member 16, and a sensor (not shown) is provided in the ignition means accommodating chamber 23.
An igniter 4 that is activated by a signal from the igniter 4 and a transfer charge container 53 filled with a transfer charge 5 ignited by the igniter 4 are provided. The center cylinder member 16 has an igniter holding member 24. The holding member 24 is fitted with an inward flange 25 for restricting the axial movement of the igniter 4 and an inside of the center cylinder member 16 in which the igniter is fitted. It comprises a peripheral wall portion 26 fixed to the peripheral surface, and a caulking portion 27 for fixing the igniter in the axial direction between the inward flange portion 25 by caulking. The central tubular member 16 also has a through hole 54 at the other end. In the case of the present embodiment, six through-holes having a diameter of 2.5 mm are arranged at equal intervals in the circumferential direction, and the through-holes 54 are closed by seal tapes 52 '.

The central cylindrical member 16 has a thickness of 1.2 to 2.0 m.
m or 1.2-3.0 mm stainless steel plate is formed into a tube which is rolled into a tube and welded, and 17-20 mm or 17-2
It can have an outer diameter of 2 mm. Such a welded pipe is a UO press method (a sheet is formed into a U shape and then formed into an O shape and a seam is welded), or an electric resistance welded pipe method (a sheet is formed into a circular shape and pressure is applied to the seam. In addition, a large current is applied while welding is performed by resistance heat).

The coolant / filter 7 comprises a gas generating agent 6
, And defines an annular chamber, that is, a combustion chamber 28 around the central cylindrical member 16. The coolant filter 7 is formed by stacking stainless steel flat knit wire meshes in the radial direction and compressing them in the radial and axial directions. The coolant filter 7 has a shape in which a loop-shaped stitch is crushed in each layer, which forms a layer in the radial direction. Therefore, the void structure of the coolant filter becomes complicated, and this coolant filter has an excellent trapping effect. Outside the coolant / filter 7, the coolant / filter 7 functions as a restraining means for suppressing the bulging of the coolant / filter 9 so that the coolant / filter 7 does not bulge due to gas pressure when the gas generator is operated and does not close the gap 9. An outer layer 29 is formed. This outer layer 29
For example, in addition to using a laminated metal net, it can also be formed using a porous cylindrical member having a plurality of through-holes in the peripheral wall surface, or a belt-shaped restraining layer in which a band member having a predetermined width is formed into an annular shape. When the outer layer 9 is formed using a laminated wire mesh,
The outer layer 29 can also have a cooling function. The coolant filter 7 defines a combustion chamber 28, cools combustion gas generated in the combustion chamber, and collects combustion residues. This coolant filter is formed at substantially the same height as the inside of the housing as shown in FIG. 1 to define the combustion chamber 28, and is formed below the height inside the housing as shown in FIG. Thus, it can be disposed in the housing.

That is, in the gas generator for an air bag shown in FIG. 10, the coolant filter 307 is formed such that its length in the axial direction is regulated so as to be lower than the height inside the housing 303, and the diffuser is formed. Shell 301
Near the gas outlet 311 on the side of the diffuser shell 30
It is disposed after a gap 309 is secured between the inner surface of the first member and the inner surface of the first member. Coolant filter 307 thus formed
Since the height of the coolant filter is lower than that of the coolant filter 7 shown in FIG. 1, in order to make the weight equal to that of the coolant filter 7 shown in FIG. And / or the inner diameter is adjusted.
A plate member 332 is provided on the inner surface of the upper end of the coolant filter 307, and a plate member 3 is provided on the outer periphery of the bottom surface.
33 are provided respectively. Plate member 332
Prevents a short path from the end of the coolant filter 307 on the diffuser shell 301 side, further positions the coolant filter 307, and the plate member 333 prevents the combustion gas from flowing directly into the gap 309. In addition, after the coolant filter 307 is inserted, the coolant filter 307 can be held by pressing the coolant filter 307 into the inner surface of the peripheral wall 310 of the diffuser shell 301. After supporting the coolant / filter 307 with the plate member 333, the closure shell 302 is covered, and the plate member 3 is welded at a predetermined position.
The end of the closure shell 302 on the side of the closure shell 302 hits the inclined portion 331 of the closure shell 302, and the coolant / filter 307 is securely held. When the coolant filter is formed as shown in FIG. 10, more space can be secured on the closure shell side than in the coolant filter 7 shown in FIG. As a result, when accommodating the same amount of gas generating agent as the gas generator shown in FIG. 1, the overall height of the gas generator can be reduced while maintaining the outer diameters of both shells. In FIG. 10, members that are substantially the same as those in FIG. 1 are given the same reference numerals, and descriptions thereof are omitted.

In the gas generator shown in FIG. 1, an inclined portion 31 is formed in the circumferential direction surrounding the circular portion 30 of the closure shell, and the inclined portion 31 serves as a movement preventing means for preventing the coolant / filter 7 from moving. In addition to functioning, it also functions as a means for forming a gap between the outer peripheral wall 8 of the housing and the coolant / filter 7.

A large number of solid gas generating agents 6 are provided in the combustion chamber 28. The gas generating agent 6 has a hollow cylindrical body,
Due to this shape, the combustion takes place on the outer and inner surfaces, with the advantage that the surface area of the entire gas generant does not change much as the combustion proceeds.

A plate member 32 is provided at the upper end of the coolant / filter 7 and a plate member 33 is provided at the lower end. The plate member 32 has a circular portion 36 for closing the upper end opening 40 of the coolant filter 7.
And a peripheral wall portion 34 formed integrally with the circular portion 36 and in contact with the inner peripheral surface 41 of the coolant filter. The circular portion 36 has a central hole 35 fitted on the outer periphery of the central cylindrical member 16. Further, the peripheral wall portion 34 is disposed so as to face the flame through hole 54 of the ignition means, and the through hole 54
It covers the nearby coolant / filter inner peripheral surface 41. The peripheral wall portion 34 has a function of protecting the coolant filter against a flame ejected toward the coolant filter 7, and at the same time, changing the direction of the flame to allow the flame to sufficiently turn around the gas generating agent 6. This plate member 3
Numeral 2 is fixed to the central cylindrical member 16 with respect to radial movement, functions as a means for positioning the coolant / filter 7 when assembling the gas generator, and when the gas generator is activated, the inner surface 37 of the housing is actuated by the pressure of the combustion gas. When a gap is formed between the coolant and the filter end face 38, the gap also functions as a short path preventing means for preventing a so-called short path of the combustion gas, in which the combustion gas passes through the gap without passing through the coolant / filter.

The plate member 33 includes a circular portion 50 for closing the lower end opening 42 of the coolant filter 7 and a peripheral wall portion 51 formed integrally with the circular portion 50 and in contact with the inner peripheral surface 41 of the coolant filter. Consists of Circular part 5
Numeral 0 has a central hole 39 fitted on the outer periphery of the central cylindrical member 16 and abuts against the charged gas generating agent to suppress the movement of the gas generating agent. The plate member 33 is sandwiched between the central tubular member 16 and the coolant / filter 7 by elastic force to prevent a short path of the combustion gas on the end surface 43 of the coolant / filter opposite to the end surface 38 and to prevent a short path during welding. In addition, it also functions as a welding protection plate.

A gap 9 is formed between the outer peripheral wall 8 of the housing and the outer layer 29 of the coolant / filter. The gap 9 forms a gas passage around the coolant filter 7 having a circular cross section in the radial direction. In the case of the present embodiment, the radial cross-sectional area of the gas passage is constant, but, for example, the coolant filter is formed in a conical shape so that the radial cross-sectional area of the gas passage increases as approaching the gas outlet 11. You can also. In this case, the radial cross-sectional area of the gas passage can take an average value. The area St in the radial cross section of the gas passage is larger than the total sum At of the opening areas S of the gas outlets 11 of the diffuser shell. Due to the presence of the gas passage around the coolant filter, the combustion gas passes through the entire area of the coolant filter toward the gas passage, thereby achieving effective use of the coolant filter and effective cooling and purification of the combustion gas. Is done. The cooled and purified combustion gas reaches the gas outlet 11 of the diffuser shell through the gas passage.

Although the present embodiment has been described with reference to an example in which a gap is formed between the outer peripheral wall of the housing and the coolant / filter, the gap may be omitted.

The gas outlet 11 of the diffuser shell is closed by an aluminum tape 52 to prevent moisture from entering the housing 3 from the outside.

When assembling the present gas generator, the diffuser shell 1 to which the central tubular member 16 is joined is placed with its protruding circular portion 13 at the bottom, the plate member 32 is passed through the central tubular member 16, and the peripheral wall of the plate member 32 is The coolant / filter 7 is fitted to the outside, thereby positioning the coolant / filter 7, filling the inside with the solid gas generating agent 6, and further placing the plate member 33 thereon. Thereafter, the central hole 15 of the closure shell is inserted into the central tubular member 16, the flange portion 20 of the closure shell is overlaid on the flange portion 19 of the diffuser shell, laser welding 21 and 44 are performed, and the diffuser shell 1, the closure shell 2, and The closure shell 2 and the central tubular member 16 are joined. Finally, the transfer charge container 53 and the igniter 4 are inserted into the central cylindrical member 16, and the caulking portion 27 of the igniter holding member is caulked to fix them.

In the gas generator constructed as described above, when an impact is detected by a sensor (not shown), a signal is sent to the igniter 4 to activate the igniter 4, whereby the transfer charge container 53 is activated. The transfer charge 5 inside ignites to generate a high-temperature flame. This flame is ejected from the through-hole 54,
In addition to igniting the gas generating agent 6 in the vicinity, the course is bent by the peripheral wall portion 34 to ignite the gas generating agent in the lower part of the combustion chamber. As a result, the gas generating agent burns to generate a high-temperature and high-pressure gas, and this combustion gas passes through the entire area of the coolant / filter 7, during which it is effectively cooled, and the combustion residue is collected. -The purified combustion gas passes through the gas passage (gap 9), breaks the wall of the aluminum tape 52, and is jetted from the gas discharge port 11 to form an airbag (not shown).
Flows into. This inflates the airbag and forms a cushion between the occupant and the rigid structure to protect the occupant from impact. The step portion 49 of the diffuser shell circular portion,
The bent portion 14 of the closure shell circular portion provides rigidity to the ceiling and the bottom of the housing to prevent deformation of the housing due to gas pressure. In addition, the flange portions 19 and 20 which are overlapped and joined in the vicinity of the position on the axial center cross section of the housing provide rigidity to the outer peripheral wall 8 of the housing and prevent deformation of the housing due to gas pressure. Further, when a gap is formed at the end face of the coolant filter, the short path of the combustion gas is prevented by the plate members 32 and 33.

FIG. 3 is a sectional view of a gas generator for an air bag according to another embodiment of the present invention. This embodiment is effective mainly as a gas generator having a housing outer diameter of about 60 mm. The gas generator includes a housing 63 including a diffuser shell 61 and a closure shell 62, an igniter 64 disposed in a housing space in the housing 63, and a solid that is ignited by the igniter 64 to generate a combustion gas. It includes a gas generant 66 and a coolant filter 67 defining a combustion chamber 84 containing the gas generant 66.

The diffuser shell 61 is formed by pressing a stainless steel plate by pressing, and includes a circular portion 78, a peripheral wall portion 76 formed on an outer peripheral portion thereof, and a flange portion 86 extending radially outward at a distal end portion thereof. Have. Surrounding wall 7
6, a plurality of gas outlets 77 are provided at equal intervals in the circumferential direction. As shown in FIG. 4, the diffuser shell 61 has a plurality of, in this embodiment, six, radial rib-shaped reinforcing members 79 radially arranged in the circular portion 78. These rib-like reinforcements 79 are provided in a housing, in particular, a diffuser shell circular portion 78 forming a ceiling portion thereof.
To provide rigidity, thereby preventing the housing from being deformed by gas pressure. As shown in FIG. 4, the flange portion 86 of the diffuser shell has a mounting portion 97 for mounting the pad module to the mounting bracket. This mounting part 97
Are disposed at intervals of 90 degrees in the circumferential direction of the flange portion 86 and have mounting holes 112 for screw bolts.

The closure shell 62 is formed by pressing a stainless steel plate by pressing, and includes a circular portion 71, a peripheral wall portion 72 formed on an outer peripheral portion thereof, and a flange portion 87 extending radially outward at a tip portion thereof. Have. Circular part 71
A concave portion 73 is formed at a central portion by a step portion 48, and a central hole 74 is formed at a central portion of the concave portion 73. The central hole 74 has an axial bent portion 75 at the edge of the hole, and the bent portion 75 is formed on the inner peripheral surface 8 into which the body 80 of the igniter fits.
1 and an end face 83 to which a collar 82 of the igniter is locked. Due to the configuration of the inner peripheral surface 81 of the axially bent portion 75, a relatively large sealing surface is ensured. To ensure airtightness,
The sealing material can be filled between the body 80 and the inner peripheral surface 81 of the igniter, and welding can be performed between the flange 82 and the end surface 83 of the igniter. The end face 83 to which the collar 82 of the igniter is locked prevents the igniter 64 from coming off due to the gas pressure in the combustion chamber 84. The step portion 48 includes a housing,
In particular, the closure shell circular part 71 forming the bottom is provided with rigidity, and the concave part 73 is provided with the connector bottom surface 8 of the igniter.
5 is located at a position inside the outer surface of the circular portion 71.
The bent portion 75 provides rigidity to the edge of the central hole 74.

The flange portion 86 of the diffuser shell and the flange portion 87 of the closure shell are put together near a position on the axially central cross section of the housing and laser welded 88, and the diffuser shell 61 and the closure shell 62 are joined to each other. Thus, a housing 63 is formed. These flange portions 86 and 87 provide rigidity to the outer peripheral wall 68 of the housing and prevent deformation of the housing due to gas pressure.

[0062] The igniter 64 comprises a conventional electric igniter which is activated by a signal from a sensor (not shown). An electric igniter is preferable to a mechanical igniter because it has a simple structure without a mechanical mechanism and is small and lightweight. The igniter 64 (output: 300 to 1500 psi in a 10 cc closed pressure vessel) does not have any similar to the transfer charge vessel 53 of FIG. This is due to the good ignitability and combustibility of the gas generating agent 66. The gas generating agent 66 has a hollow cylindrical shape, and has such an advantage that the combustion occurs on the outer surface and the inner surface, and the surface area of the entire gas generating agent does not change much as the combustion proceeds.

The coolant filter 67 has a central hole 74.
And a combustion chamber 84 with the housing 63. This coolant filter 67 is formed by stacking stainless steel flat knit wire meshes in the radial direction and compressing them in the radial and axial directions. This coolant filter 67
Thereby, the combustion chamber 84 is defined, the combustion gas generated in the combustion chamber is cooled, and the combustion residue is collected. An outer layer 89 made of a laminated metal mesh is formed outside the coolant / filter 67. This outer layer 89
Reinforces coolant / filter and cools gas.

Since the closure shell is press-formed, it surrounds the circular portion 71 and has a circumferentially inclined portion 90.
Are formed inevitably, and the inclined portion 90
It functions as a means for preventing the positioning or movement of the filter 67 and also as a means for forming a gap 69 between the outer peripheral wall 68 of the housing and the outer layer 89 of the coolant filter.

A large number of solid cylindrical gas generating agents 66 are provided in the combustion chamber 84. The gas generating agent 66 directly
The movement of the coolant filter 67 is restricted by a circular portion 92 of a plate member which is filled in the space inside the combustion chamber and is disposed adjacent to the igniter 64 and closes the one end opening 45 of the coolant filter 67. The plate member 91 is provided on the peripheral wall 9 integral with the circular portion 92 and abutting against the inner peripheral surface of one end of the coolant filter 67 to cover the inner peripheral surface.
Three. This plate member 91 prevents a short path of the combustion gas between the one end surface 94 of the coolant filter and the inner surface of the circular portion 78 of the diffuser shell. The end face 95 at the other end of the coolant / filter on which the plate member 91 is not provided is fixed to the housing inner face 46 by welding. Thereby, a short path at the end face 95 is prevented. The welding eliminates the need for a flame-retardant and elastic packing made of, for example, silicone rubber, which is usually provided between the end face of the coolant / filter and the inner face of the housing.

The outer peripheral wall 68 of the housing and the coolant
A gap 69 is formed between the outer layers 89 of the filter, and the gap 69 forms a gas passage around the coolant filter 67 having a circular cross section in the radial direction. As in the gas generator shown in FIG. 1, the area of the gas passage in the radial section is larger than the sum of the opening areas of the respective gas discharge ports 77 of the diffuser shell. Coolant·
Due to the presence of the gas passage around the filter, the combustion gas passes through the entire area of the coolant filter toward the gas passage, thereby achieving effective use of the coolant filter and effective cooling and purification of the combustion gas. . The cooled and purified combustion gas reaches the gas outlet 77 of the diffuser shell through the gas passage. In order to prevent moisture from entering the housing 63 from the outside, the gas outlet 7 of the diffuser shell is formed by aluminum tape 96.
7 is closed from the inside of the housing.

When assembling the present gas generator, the circular portion 71 of the closure shell is set to the bottom to close the closure shell 6.
2 and the igniter 64 is disposed in the central hole 74. Next, the coolant / filter 67 is provided, the inside thereof is filled with the solid gas generating agent 66, and the plate member 91 is further provided thereon. Finally, the flange portion 86 of the diffuser shell is placed over the flange portion 87 of the closure shell, and laser welding 88 is performed to join the diffuser shell 61 and the closure shell 62.

In the gas generator constructed as described above, when an impact is detected by a sensor (not shown), the signal is sent to the igniter 64 to operate the igniter 64, whereby the combustion chamber 84 Is ignited. As a result, the gas generating agent burns to generate high-temperature, high-pressure gas,
The combustion gas enters the coolant filter 67 from the entire area of the coolant filter 67, is cooled while passing through the coolant filter 67, and captures combustion residues. The cooled and purified combustion gas passes through a gas passage formed by the gap 69, breaks through the wall of the aluminum tape 96, is ejected from the gas outlet 77, and flows into an airbag (not shown). This causes the airbag to inflate and form a cushion between the occupant and the rigid structure, protecting the occupant from impact. The rib-like body 79 of the diffuser shell circular portion and the stepped portion 48 and the bent portion 75 of the closure shell circular portion provide rigidity to the ceiling and the bottom of the housing to prevent deformation of the housing due to gas pressure. Further, flange portions 86 and 8 which are overlapped and joined in the vicinity of the position on the axial center cross section of the housing.
7 provides rigidity to the outer peripheral wall 68 of the housing to prevent deformation of the housing due to gas pressure. Further, when a gap is formed at the end face of the coolant / filter, the short path of the combustion gas is prevented by the plate member 91.
Further, since the opposite end face 95 is fixed to the inner surface of the housing by welding, no gap is formed between the two.

FIG. 5 is similar to the gas generator of FIG. 1, and shows an example in which a diffuser shell 1 'and a closure shell 2' are formed by casting using an aluminum alloy. The diffuser shell 1 'has a circular portion 12', a central cylindrical portion 16 'formed integrally therewith, a peripheral wall portion 10' formed on the outer peripheral portion of the circular portion 12 ', and a radially outer Has a flange portion 19 'extending therethrough. The closure shell 2 'has a circular portion 30', a central hole 15 'formed at the center thereof, a peripheral wall portion 47' formed at the outer peripheral portion of the circular portion 30 ', and a peripheral wall portion 47'.
Has a flange portion 20 'extending outward in the radial direction. The central hole 15 'fits around the outer periphery of the central cylindrical portion 16', the flange portion 19 'of the diffuser shell and the flange portion 20' of the closure shell are overlapped, laser welded 21 'is performed, and the diffuser shell and the closure shell are formed. Are joined to form a housing 3 '. The same members as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted.

FIG. 6 is similar to the gas generator of FIG. 3 and includes a diffuser shell 61 ′ and a closure shell 6.
An example in which 2 ′ is formed by casting using an aluminum alloy is shown. The diffuser shell 61 'has a circular portion 78'.
And a peripheral wall portion 76 ′ formed on the outer peripheral portion thereof, and a flange portion 86 ′ extending radially outward at the distal end portion. The closure shell 62 'has a circular portion 71', a peripheral wall portion 72 'formed on an outer peripheral portion thereof, and a flange portion 87' extending radially outward at a distal end thereof.
A central hole 74 'is formed at the center of the circular portion 71'. The body 80 of the igniter 64 fits into the central hole 74 ', and the flange 82 of the igniter 64 is locked on the inner surface 129 of the circular portion 71' of the closure shell. The flange portion 86 'of the diffuser shell and the flange portion 87' of the closure shell are overlapped and laser welded 88 ', and the diffuser shell 61' and the closure shell 6 are welded.
2 'are joined together to form a housing 63'.

FIG. 7 shows an example of an airbag apparatus having the gas generator of the present invention. 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.

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 bends when an acceleration is applied, and these semiconductor strain gauges are bridge-connected. When acceleration is applied, the beam deflects, causing strain on the surface. 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 shock signal from the sensor exceeds a certain value, the control unit 202 starts the calculation, and outputs an operation signal to the igniter 4 of the gas generator 200 when the calculation result exceeds a certain value.

The module case 203 is made of, for example, polyurethane and includes a module cover 205. The airbag 20 is accommodated in the module case 203.
4 and the gas generator 200 are accommodated and configured as a pad module, and this pad module is attached to the steering wheel 207 of the automobile.

The airbag 204 is formed of nylon (eg, nylon 66), polyester, or the like.
The bag mouth 206 surrounds the gas outlet of the gas generator,
It is fixed to the flange of the gas generator in a folded state.

When a semiconductor type acceleration sensor 201 detects a shock at the time of a car collision, the signal is sent to the control unit 202, and when the shock signal from the sensor exceeds a certain value, the control unit 202 starts calculation, When the calculated result exceeds a certain value, the gas generator 20
An operation signal is output to the igniter 4 of 0. Thereby, the igniter 4 operates to ignite the gas generating agent, and the gas generating agent burns to generate gas. This gas is blown into the airbag 204, whereby the airbag breaks the module cover 205 and bulges, forming a cushion between the steering wheel 207 and the occupant to absorb impact.

[0078]

In the gas generator according to the present invention, the deformation of the housing during the operation of the gas generator is prevented by the structure of the flange portion, so that the normal combustion of the gas generating means and the normal combustion of the combustion gas. The flow and the like are assured, the thickness of the housing is reduced, and a small and lightweight gas generator can be realized.

Further, the gas generator having the flange portion in the diffuser shell can avoid the danger of damaging the airbag side, that is, the occupant side, even if the welded portion is broken.

By forming the diffuser shell and the closure shell by pressing, the manufacturing cost can be reduced and the diffuser shell and the closure shell can be easily manufactured.

By providing the rib-like reinforcing member and / or the reinforcing step on either or both the circular portion of the diffuser shell and / or the circular portion of the closure shell, the housing when the gas generator is operated, particularly the housing, The deformation of the circular part is prevented. As a result, a short path of the combustion gas is prevented between the inner surface of the circular portion and the end surface of the filter means, and normal deployment of the airbag is always ensured.

[Brief description of the drawings]

FIG. 1 is a sectional view of a gas generator according to an embodiment of the present invention.

FIG. 2 is a plan view of the gas generator.

FIG. 3 is a cross-sectional view of a gas generator according to another embodiment of the present invention.

FIG. 4 is a plan view of the gas generator.

FIG. 5 is a half sectional view of a gas generator according to still another embodiment of the present invention.

FIG. 6 is a partial sectional view of a gas generator according to still another embodiment of the present invention.

FIG. 7 is a configuration diagram of an airbag device of the present invention.

FIG. 8 is a half sectional view of a conventional gas generator.

FIG. 9 is a cross-sectional view of a conventional gas generator.

FIG. 10 is a cross-sectional view of a gas generator according to another embodiment of the present invention.

FIG. 11 is a plan view of a gas generator according to still another embodiment of the present invention.

[Description of Signs] 1 diffuser shell 2 closure shell 3 housing 4 igniter 6 gas generating agent 7 coolant / filter 8 outer peripheral wall 9 gap 10 peripheral wall 11 gas outlet 12 circular part 15 center hole 19 flange part 20 flange part 28 combustion Room 30 Circular part 47 Peripheral wall part 49 Reinforcing step part 79 Rib-shaped reinforcement

Claims (24)

[Claims] 1. A first circular portion having no processed hole, a peripheral wall formed on an outer peripheral portion of the circular portion and having a plurality of gas outlets, and a radial direction at a tip end of the peripheral wall portion. A diffuser shell having an outwardly extending flange portion; a space formed with the diffuser shell; a second circular portion; a central hole formed in a central portion of the second circular portion; A housing formed of a closure shell having a peripheral wall portion formed on the outer peripheral portion of the circular portion and a flange portion extending radially outward at a distal end portion of the peripheral wall portion; and a central hole of the closure shell in the space. An igniting means disposed, a gas generating means disposed in the space surrounding the igniting means and ignited by the igniting means to generate a combustion gas; and Inside the inner peripheral wall of the Filter means for cooling the combustion gas and collecting combustion residues, wherein the flange portion of the diffuser shell and the flange portion of the closure shell are joined. Generator. 2. The gas generator for an airbag according to claim 1, wherein the diffuser shell and the closure shell are each formed by press-molding a plate. 3. The gas generator for an airbag according to claim 1, wherein the flange portion of the diffuser shell has a mounting portion for mounting a pad module to a mounting bracket. 4. The gas generator for an airbag according to claim 1, wherein the flange portion of the diffuser shell and the flange portion of the closure shell are joined by welding. 5. A rib-shaped reinforcing member and / or a reinforcing step portion is formed on at least one of the first circular portion of the diffuser shell and the second circular portion of the closure shell. Item 5. The gas generator for an airbag according to any one of Items 1 to 4. 6. The gas generator for an airbag according to claim 1, wherein the central hole of the closure shell has a bent portion in the axial direction in which the ignition means is provided at an edge of the hole. 7. The flange portion of the diffuser shell and the flange portion of the closure shell are superposed and joined at or near the axial center cross section of the housing. A gas generator for an airbag as described in the above. 8. The gas generator for an airbag according to claim 1, wherein the diffuser shell and the closure shell are each made of a metal plate having a thickness of 1.2 to 3.0 mm. 9. The gas generator for an airbag according to claim 8, wherein the metal plate is any one of a stainless steel plate, a nickel-plated steel plate, and an aluminum alloy plate. 10. The gas generator for an airbag according to claim 1, wherein the diffuser shell and the closure shell each have an outer diameter of 45 to 75 mm. 11. The height from the top surface of the diffuser shell to the bottom surface of the closure shell is 25 to 40 mm.
The gas generator for an airbag according to any one of claims 1 to 10, wherein 12. A gas generator according to claim 1, a shock sensor for detecting a shock and outputting a detection signal thereof, and a control unit for inputting said detection signal and outputting an operation signal to ignition means of said gas generator. An airbag device comprising: an airbag that inflates by introducing gas generated by the gas generator; and a module case that houses the airbag. 13. The airbag device according to claim 12, wherein each of the diffuser shell and the closure shell is formed by pressing a plate. 14. The airbag device according to claim 12, wherein the flange portion of the diffuser shell has a mounting portion for mounting a pad module to a mounting bracket. 15. The airbag device according to claim 12, wherein the flange portion of the diffuser shell and the flange portion of the closure shell are joined by welding. 16. A rib-shaped reinforcing member and / or a reinforcing stepped portion is formed on at least one of the first circular portion of the diffuser shell and the second circular portion of the closure shell. Any one of items 12 to 15
The airbag device according to any one of the preceding claims. 17. The airbag device according to claim 12, wherein the central hole of the closure shell has a bent portion in the axial direction in which the ignition means is disposed at an edge of the hole. 18. The flange portion of a diffuser shell and the flange portion of a closure shell are superposed and joined at or near a position on a central axial cross section of the housing. The airbag device as described in the above. 19. The airbag device according to claim 12, wherein each of the diffuser shell and the closure shell is made of a metal plate having a thickness of 1.2 to 3.0 mm. 20. The airbag device according to claim 19, wherein the metal plate is any one of a stainless steel plate, a nickel-plated steel plate, and an aluminum alloy plate. 21. The airbag device according to claim 12, wherein each of the diffuser shell and the closure shell has an outer diameter of 45 to 75 mm. 22. A height from an upper surface of the diffuser shell to a lower surface of the closure shell is 25 to 40 mm.
The airbag device according to any one of claims 12 to 21, wherein 23. The housing according to claim 1, further comprising a central tubular member formed of a tube and disposed concentrically with a central hole of the closure shell and forming a hollow chamber for ignition means therein. The gas generator for an airbag according to claim 1. 24. The housing according to claim 12, wherein a central tubular member formed of a tube and arranged concentrically with a central hole of the closure shell and forming a hollow chamber for ignition means is provided inside the housing. The airbag device according to claim 1.