JP2781807B2 - Gas filter for gas generator - Google Patents

Abstract

PURPOSE:To improve the dimension accuracy by making a gas filter of sintered material of unified wire gauzes or the like, and provide a gas filter for stabilizing the performance of a gas generator. CONSTITUTION:A gas filter 21 of a gas generator, in which the gas generating agent is housed inside of a container thereof and a gas filter 21 is arranged in a gas passage inside of the container, is obtained by forming a sintered material 22, which has plural wire gauzes 22a, 22b, 22c unified together, into the circular or cylindrical shape.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas filter for a gas generator used in a vehicle airbag.

[0002]

2. Description of the Related Art First, a gas generator used by incorporating a gas filter will be described. 2. Description of the Related Art In recent years , airbag systems have been put into practical use in order to protect occupants from shocks that occur during a vehicle collision. The airbag is attached to a handle or an instrument panel, and is inflated like a balloon by gas supplied from a gas generator at the time of a collision and serves as a cushion between the handle and the like and a human to protect an occupant. FIG. 6 shows a specific example of such a gas generator.
Shown in FIG. 6 is a sectional view of a gas generator used on the driver's seat side. In FIG. 6, a gas generator 1 is a cylindrical container, and is formed by integrating an upper container 2 and a lower container 3 by friction welding or the like, and is divided into three chambers in the radial direction by partition walls 2a and 2b.
Gas holes 4, 5, 6 are provided in the partition walls 2a, 2b and the outer wall 2c.
Is opened to allow communication between each chamber and the outside. An ignition device 8 is inserted into the central chamber from below, and a transfer charge 9 is disposed in contact with the ignition device 8. A gas generating agent 7 and a first gas filter 11a are disposed in the intermediate chamber, and a second gas filter 11a is disposed in the outermost chamber. 11
b is arranged. The igniter 8 has an ignition agent and a heater inside and is connected to a power supply (not shown). When a vehicle collides, the ignition device 8 is energized and heated through a collision sensor (not shown) to ignite the ignition agent and the flame causes the ignition agent to transfer. 9 is ignited and burns. The hot air of the transfer charge 9 flows into the intermediate chamber through the gas holes 4 and causes a chemical reaction of the gas generating agent 7 to generate a large amount of high-temperature gas in a short time. This gas is the first
Cooling and slag removal are performed by sequentially passing through the gas filter 11a and the second gas filter 11b, and a clean gas at an appropriate temperature is supplied from the gas holes 6 to an airbag (not shown).

Next, the above-mentioned gas filter will be described with reference to FIG. FIG. 5 is a perspective view of the gas filter.
In FIG. 5, the gas filter 11 is obtained by winding a wire mesh alone or a wire mesh and a sintered filter together in a spiral shape into a cylindrical shape, and fixing an end portion by spot welding 12 or the like. When the height H of the gas filter 11 is poor in dimensional accuracy and smaller than a predetermined value, when the gas filter 11 is incorporated in a gas generator, the gap G between the gas filter 11 and the container in FIG. 6 becomes large, and gas may leak from this portion. . Conversely, if it is larger than the predetermined value, it cannot be incorporated, or it will be deformed when incorporated. The same applies when the dimensional accuracy of the diameter D of the gas filter 11 is poor.

[0004]

The above-described gas filter 11 is formed by winding a wire mesh having elasticity and easily changing shape while applying tension thereto.
There is a problem in that the dimensional accuracy is very poor, and in the case of the dimension of the height H, it is difficult to manage the number of wire meshes and the like.

The present invention has been made in view of the above-mentioned problems of the prior art, and an object of the present invention is to provide a dimensional accuracy by forming a sintered body such as an integrated wire mesh. And to provide a gas filter that stabilizes the performance of the gas generator.

[0006]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention relates to a gas filter in a gas generator in which a gas generating agent is housed in a container and a gas filter is provided in a gas passage in the container. And the gas filter is a coarse mesh
Of inner and outer layers as strength members formed in
It is a filtration member formed by a fine wire mesh placed between
And a wire mesh consisting of three layers.
The laminate was integrated by sintering and formed into a cylindrical shape
It is characterized by the following .

[0007] In addition, a plurality of wire meshes for each layer are formed,
It is preferable to displace the positions of these wire meshes
No. Further, the intermediate layer may be a laminate of a wire mesh and a metal fiber filter .

Further, at least the upper surface and / or the lower surface of these gas filters may be crushed.

The gas filter is plain-woven with a first group of thick metal wires arranged substantially in parallel at a predetermined interval and a second group of thin metal wires arranged closely in a direction substantially perpendicular thereto. A filter laminate consisting of at least two layers of a tatami plain weave wire mesh and a metal fiber filter is
And the obtained sintered body is filtered by the fiber filter.
The second group of thin metal wires is circular
It shall be cylindrically shaped so as to be located in the circumferential direction
You can also.

[0010]

[0011]

When a plurality of wire meshes are stacked (laminated) and pressed (sintered) at a high temperature, the wires are mainly entangled to generate a bonding force, and the whole is integrated. The sintering naturally includes an original sintering accompanied by a chemical change or a metallurgical change such as melting, and the same holds true even if a bonding force is generated by the original sintering. Since the integrated sintered body has a fixed form, it can be cut with high precision when cut into a predetermined length and width, and when formed into a cylindrical shape, a gas filter with high dimensional accuracy can be obtained.

Further, when forming the sintered body in combination with a conventional sintering fiber filters and wire mesh using metal fibers, combines filtration performance is a feature of fine fiber filter strength and eyes is a feature of the wire mesh A gas filter can be obtained.

Further, when the upper or lower surface of the gas filter is crushed with a grinder or the like, the burrs of the wire of the sintered body fill the eyes near the surface and the gas cannot pass therethrough. Therefore, a filter cover for preventing gas leakage is not required.

Further, the cylindrical gas filter is required to have a strength in the circumferential direction rather than the axial direction since a tensile force acts in the circumferential direction due to the internal pressure. On the other hand, in the tatami plain weave, the direction of the second group of thin metal wires is closer to the direction of the second group of thin metal wires, and therefore, compared to the direction of the first group of thick metal wires that are spaced apart. It has a large cross-sectional area and tensile strength proportional to its cross-sectional area. Therefore, by forming the wire mesh layer with the second group of thin metal wires arranged in the circumferential direction, the strength can be maximized. On the other hand, in this case, when the wire mesh is cut to a predetermined width in the manufacturing process, the wire mesh is cut along the thin metal wires closely arranged, and the cutting becomes difficult, for example, the outermost wire is frayed and comes off. However, if the wire mesh is sintered integrally with the fiber filter, fraying at the time of cutting can be prevented, and cutting becomes easy.

In the production of the above gas filter, first, a sheet-shaped sintered body is formed, the sintered body is formed into a cylindrical shape, and the butted portions are joined by welding or the like, and then cut into a predetermined width. Alternatively, a method of forming a ring-shaped gas filter by cutting the sintered body to a predetermined width and then joining the butted portions by welding or the like substantially uses the conventional manufacturing process of a sintered fiber filter as it is. The manufacturing cost does not increase. In addition, since the sintered body is formed into a cylindrical shape by abutting both ends, the process can be simplified and the production efficiency is high.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view of a gas filter of the present invention,
FIG. 2 is a sectional view of the sintered body of FIG. 1, FIG. 3 is a view showing an embodiment in which a filter cover is not required, and FIG. 4 is a view showing an embodiment of a composite filter using a tatami plain weave wire mesh. Note that, in FIG. 3, portions having the same functions as those in FIG. 6 are denoted by the same reference numerals, and description thereof will be omitted.

First, the structure will be described with reference to FIG. In FIG. 1, the gas filter 21 includes three wire mesh layers 22a, 2
A sintered body 22 in which 2b and 22c are integrated is bent into a cylindrical shape with both ends butt, and the butt portions are joined by welding, brazing, or the like 23. Outer wire mesh layer 2
The wire mesh 2a and the inner wire mesh layer 22c are composed of two relatively coarse meshes. The intermediate wire mesh layer 22b is composed of three relatively fine meshes. The coarseness of the outer layer and the inner layer is for improving mechanical strength, and the fineness of the intermediate layer is for improving filtration performance. Further, the reason why the number of the wire meshes in each layer is plural is to improve the filtration performance by shifting the mesh positions of the wire meshes. Thus, by combining appropriately selecting the mesh size of the wire mesh, Ru obtained gas filter having both the desired mechanical strength and filtration performance.

The wire mesh layer 22b as an intermediate layer may be constituted by a fiber filter. This way,
A gas filter having both the mechanical strength of a wire mesh and the filtering performance characteristic of a fiber filter can be obtained.

As described above, since the integrated sintered body is formed into a cylindrical shape, the obtained gas filter has higher dimensional accuracy than a conventional wire filter in which a wire mesh is wound up.

Next, a manufacturing method will be described with reference to FIG. In FIG. 2, the sintered body 22 has three wire mesh layers 22.
a, 22b, and 22c, and two wire mesh layers 22a and 22c, and three wire mesh layers 22b each made of a sheet-like wire mesh using a material such as stainless steel. Then, these superposed wire meshes are pressed and integrated in a softened state while being heated to about 1000 ° C. in a sintering furnace. As the wire mesh, plain weave or knitted fabric is used. When pressed at a high temperature, the wires are mainly entangled to generate a mechanical bonding force, and the whole is integrated. Here, a method may be used in which the material of the wire mesh is processed and a bonding force is generated by original sintering accompanied by metallurgical changes such as chemical change or melting. This integrated sheet-shaped sintered body 22
After cutting into a predetermined length and width, the ends are butted into a cylindrical shape, and the butted portions are joined by welding, brazing, or the like, to obtain a desired gas filter. Alternatively, the sintered body 22 may be formed into a cylindrical shape first, and then cut into a predetermined width to form a gas filter. Here, depending on the application, the sintered body 22 may be pressed at room temperature to form an arc-shaped gas filter. Since the sheet-shaped sintered body 22 is given a fixed shape by integration, it can be cut with high accuracy and can be formed into a cylindrical shape by abutting both ends. Therefore, the dimensional accuracy of the obtained gas filter is improved, and the manufacturing process is simplified. Further, in the manufacturing process, the manufacturing process of the conventional sintered fiber filter can be used almost as it is, so that the manufacturing cost does not increase.

Next, a description will be given of a composite filter in which the intermediate layer is replaced with the wire mesh layer 22b and the fiber filter layer 22b 'is used. In FIG. 2, the fiber filter layer 22b 'before sintering is formed by laminating stainless fibers having a wire diameter of about 10 microns in a cushion shape. The composite filter 22 is pressed into a softened state while being heated to about 1000 ° C. in a sintering furnace and integrated into a sintered body, similarly to the case of the above-described wire mesh alone. After that, it is the same as the case of only the wire mesh.

FIG. 3 is a view showing an embodiment in which a filter cover is not required. 3 is different from FIG. 5 in that the gas generator 45 is also divided into upper and lower parts by a partition wall 44, a first filter 40 and a second filter 41 are arranged in a lower stage, and the third filter 42 is The gas filter according to the present invention is characterized in that the lower surface 42a is crushed with a grinder or the like. Such a four-chamber structure is used for the purpose of improving the slag collection rate and the like, and the generated gas 46 is used.
After passing through the second filter 41 via the first filter 40, it hits the lower surface 42a of the third filter, bypasses it, passes through the third filter from the inner diameter side, and flows out of the gas hole 45a. . For this reason, normally, a filter cover 43 for preventing gas leakage is provided on the lower surface 42a of the third filter. However, in this embodiment, since the lower surface 42a is crushed by a grinder or the like, the passage of gas is prevented. And the filter cover 43 becomes unnecessary.

FIG. 4 is a view showing an embodiment in which the inner wire mesh layer 22c is omitted in the composite filter described in FIG. 2 and one woven plain weave wire mesh is used instead of two plain weave wire meshes. . In FIG. 4, a gas filter 51 is a sintered composite filter 52 in which both ends are bent into a cylindrical shape with their ends abutted, and the abutted portions are joined by welding, brazing or the like 23. The difference from the composite filter 22 of FIG. 2 is that a woven plain-woven wire mesh 52a is used instead of the plain-woven wire mesh 22a. Wire mesh 52a tatami plain weave, between predetermined substantially parallel
The second group of thin metal wires which are closely arranged in a direction substantially perpendicular septum with a thick metal wire 53 of the first group arranged in these 54
The gas filter 51 is formed with the second group of thin metal wires 54 in the circumferential direction 55.
In this case, when the wire mesh is cut into a predetermined width in the manufacturing process, the wire mesh is cut along a thin metal wire closely arranged, and in a normal case, the outer wire is frayed and is difficult to cut. However, according to the present invention, since the wire mesh is sintered integrally with the fiber filter, fraying at the time of cutting can be prevented, and cutting is easy.

In FIG. 4, the tatami plain weave wire mesh 52a is made of a material such as stainless steel. For example, the first group of thick metal wires 53 has a wire diameter of 0.38 mm, 24 mesh, and the second group of thin metal wires 54 has a wire diameter of 24 mesh. It has a diameter of 0.25 mm and 110 mesh. In this case, the total cross-sectional area of the second group of thin metal wires 54 is about twice as large as the total cross-sectional area of the first group of thick metal wires 53. Therefore, the gas filter 51 is arranged in the circumferential direction 55 of the tatami plain weave wire mesh layer 52a. Has about twice the tensile strength as compared to the axial direction. As a result, the features of the closed woven plain weave wire mesh are fully exhibited, and a gas filter with higher strength is obtained.

[0025]

According to the gas filter for a gas generator of the present invention,
As described above, since the gas filter is cut and processed with high accuracy and the dimensional accuracy is improved by forming a sintered body in which a plurality of wire meshes are stacked and integrated as described above, variation in the gap between the gas generator and the container is reduced. Thus, the performance of the gas generator can be stabilized. Further, since the gas filter can be formed into a cylindrical shape by abutting both ends by using the sintered body, the manufacturing process of the gas filter can be simplified, and the production efficiency can be improved. Further, in the manufacturing process, the manufacturing process of the conventional fiber filter can be used almost as it is, and the manufacturing cost does not increase. Further, when the sintered body is configured by combining a wire mesh and a fiber filter, a gas filter having both the strength of the wire mesh and the filtering performance of the fiber filter can be obtained. Further, when the upper or lower surface of the gas filter is crushed with a grinder or the like, a filter cover for preventing gas leakage can be omitted. In addition, when a tatami-woven wire mesh and a fiber filter are combined, and the above-described sintered body is configured such that the thin metal wires closely arranged are arranged in the circumferential direction, a gas filter having higher strength can be obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view of a gas filter for a gas generator according to the present invention.

FIG. 2 is a cross-sectional view of the sintered body of FIG.

FIG. 3 is a diagram showing an embodiment in which a filter cover is not required.

FIG. 4 is a diagram showing an embodiment in which a tatami plain weave wire mesh and a fiber filter are combined.

FIG. 5 is a perspective view of a conventional gas filter for a gas generator.

FIG. 6 is a sectional view of a gas generator.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Gas generator 2 Upper container 3 Lower container 4 Gas hole (gas passage) 5 Gas hole (gas passage) 6 Gas hole (gas passage) 7 Gas generator 11a First gas filter 11b Second gas filter 21 Gas filter 22 Firing Bonding 22a Wire mesh layer (wire mesh) 22b Wire mesh layer (wire mesh) 22b 'Fiber filter layer (fiber filter) 22c Wire mesh layer (wire mesh) 23 Welding, brazing, etc. 42a Lower surface (the crushed surface of gas filter) 51 Gas filter 52a Tatami woven wire mesh 53 Thick metal wire 54 Thin metal wire 55 Circumferential direction

Continuation of the front page (72) Inventor Satoru Saka 2-11-11 Iwaya Minami-cho, Nada-ku, Kobe-shi, Hyogo Prefecture Inside Sensor Technology Co., Ltd. (56) References JP-A-3-284311 (JP, A) JP-A-2- 152510 (JP, A) Japanese Utility Model Showa 50-54741 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) B60R 21/26 B01D 39/12

Claims (5)

(57) [Claims] 1. A gas filter in a gas generator in which a gas generating agent is stored in a container and a gas filter is disposed in a gas passage in the container, the gas filter having a strength formed by a coarse mesh. It is composed of three layers: an inner layer (22c) and an outer layer (22a) as members, and an intermediate layer (22b) as a filtering member formed of a fine wire mesh arranged between the inner and outer layers. A gas filter for a gas generator, characterized in that a laminated body of a wire mesh is integrated by sintering and formed into a cylindrical shape. 2. The gas for a gas generator according to claim 1, wherein each of the inner layer, the intermediate layer, and the outer layer is formed by laminating a plurality of wire meshes, and the wire meshes are staggered. filter. 3. A gas filter in a gas generator in which a gas generating agent is stored in a container and a gas filter is disposed in a gas passage in the container, wherein the gas filter has a strength formed by a coarse mesh. An inner layer (22c) and an outer layer (22a) as members and an intermediate layer (22b ') as a filtering member positioned between the inner and outer layers are formed, and a laminated body composed of the three layers is integrated by sintering. A gas filter for a gas generator, wherein the intermediate layer (22b ') is formed by laminating a wire mesh and a metal fiber filter. 4. The gas filter for a gas generator according to claim 1, wherein at least an upper surface and a lower surface of the gas filter are crushed. 5. A gas filter in a gas generator in which a gas generating agent is stored in a container and a gas filter is disposed in a gas passage in the container, wherein the gas filters are disposed substantially in parallel at predetermined intervals. A tatami-woven wire mesh (52a) made of a first group of thick metal wires (53) and a second group of thin metal wires (54) arranged closely in a direction substantially perpendicular to the metal wires (53). ) And a metal fiber filter (22b '), a filter laminate comprising at least two layers is integrated by sintering, and the obtained sintered body is placed such that the fiber filter (22b') is located inside. A gas filter for a gas generator, wherein the second group of thin metal wires (54) is formed in a cylindrical shape so as to be located in a circumferential direction.