JPH0722664B2 - Gas filter and manufacturing method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention is combined with a gas generator such as an airbag for an automobile, an injection device for an emergency escape seat of an aircraft, an emergency opening / closing device for a valve, and a buoyancy generator for a ship. And a method for manufacturing the same.

(Prior Art) As a gas generator of this type, a method of using a high-temperature gas generated by burning explosive is widely adopted, but gas cooling for avoiding damage to a bag and harmful components in the gas are used. It is necessary to use a gas filter to remove the. As a filter for this purpose, a laminate of a plurality of stainless steel wire nets, a metal foam, a metal baffle plate, or the like is used.

However, since the conventional gas filters as described above have insufficient elasticity, a gap is generated when they are housed in the casing, and high-temperature gas easily short-passes. However, many problems remain such that the gas filter itself is non-homogeneous, short-circuiting of high-temperature gas is likely to occur, and it takes a lot of trouble to load the gas into the casing.

(Problems to be Solved by the Invention) The present invention solves the above-mentioned conventional problems and facilitates filling into a casing, does not easily form a gap between the casing and a thick metal wire rod. The present invention has been completed in order to provide a gas filter which is easy to melt and is less likely to melt, and which is homogeneous in itself, and in which there is no risk of short-pass of high-temperature gas, and a method for manufacturing the same.

(Means for Solving the Problem) The above problem is that a loop group of metal wire rods bent in different directions in different gear tooth shapes of modules in respective directions is surrounded by the bent fastening wire rods. This can be solved by a gas filter characterized in that it is in a state of being compression-molded in an annular shape in a state of being fastened.

Further, the above-mentioned problem is that a metal wire is bent in one direction by a first gear and then bent in a different direction by a second gear of a different module to be processed into a gear tooth shape, which is wound on a drum. A method of manufacturing a gas filter is characterized in that a loop group is formed, a bent fastening wire is wound around the loop group and fastened to a predetermined shape, and then the loop group is housed in an annular mold and compression molded. be able to.

Hereinafter, these inventions will be described in more detail with reference to Examples.

Example In the example, a heat-resistant metal wire rod such as stainless steel having a wire diameter of 0.25 to 0.45 mm is used as a material. If the wire diameter of the metal wire is too thin, it may melt due to contact with high-temperature gas, and if it is too thick, it becomes difficult to process and the gas passage becomes large and the function as a gas cooling and filter deteriorates. Becomes Therefore, the metal wire used in the filter of the present invention has a wire diameter of 0.
Heat resistant steel wire of 1 to 1.5 mm is preferable.

As shown in FIG. 1, such a metal wire (1) first passes between a pair of first gears (2), (2) which are meshed with each other, and is corrugated on one plane at a constant pitch in one direction. (Plane wave) Bent. As the first gear (2), a spur gear whose module is 4.0 to 1.0 is suitable. Next, the metal wire (1) passes between the pair of second gears (4) and (4) meshing with each other through the guide (3). Second gear (4)
When entering, the metal wire (1) is naturally twisted so that the curved surface of the first gear (2) becomes parallel to the tooth surface of the second gear (4), but the second gear (4), (4) When passing through, a concavo-convex (three-dimensional waveform) bent in a gear tooth shape in different directions with respect to this bent surface is formed. The second gear (4) is a spur gear whose module is 2.0 to 0.5. By changing the modules of the first gear (2) and the second gear (4) in this way, It is possible to obtain a metal wire rod (1) that is bent into gear tooth shapes of different modules. The ratio of the module M1 of the first gear (2) to the module M2 of the second gear (4) is M1 / M2 = 1.5.
It is preferably set to 2.5. In this embodiment, the bending pitch is 5 to 10 mm and the wave height is 3 to 6 mm.
In order to avoid breakage of the metal wire rod (1) in the bending process, the tension of the metal wire rod (1) is kept constant by setting the diameters of the first gear (2) and the second gear (4) to be the same. deep. The metal wire rod (1) bent under the above conditions is most suitable as a material for the gas filter.

The metal wire rod (1) bent into gear tooth shapes in different directions in this way is then continuously wound around a drum,
It is a multiple loop group (5) as shown in FIG. Even in this state, the metal wire rods (1) bent into different gear tooth shapes of the modules in different directions are already entangled with each other, but in the present invention, the metal wire rods (1) are further wound around the annular portion of the loop group (5). Fastening wire made of metal (6)
Is wrapped around and fastened to a predetermined shape to improve shape retention. As the fastening wire rod (6) for this purpose, one bent into a three-dimensional wave in different directions is used as in the metal wire rod (1).

The loop group (5) fastened in this way is then
It is housed in a first mold (11) composed of an annular upper mold (7), a core mold (8), an outer mold (9) and a protruding mold (10) as shown in the figure, and compression molded. . At this time, since the loop group (5) is fastened by the fastening wire rod (6) to improve the shape retention, the loop group (5) can be easily stored in the mold (11). If an annular elastic ring (12) made of urethane resin or the like is applied to the upper surface of) and compression molding is performed by the upper die (7), the metal wire rod (6) of the loop group (5) protrudes from the gap between the dies. It is possible to prevent damage to the mold (11) and generation of defective products. The bulk specific gravity after compression molding is preferably 1.0 to 3.0.

Depending on the shape of the desired gas filter, the finished product may be obtained as it is by one compression molding, but in the case of the embodiment shown in FIG. 4, the upper mold (7), the core mold (8), Second compression molding is performed by the second mold (13) including the outer mold (20) and the protruding mold (21). In this case as well, the annular elastic ring (14) made of urethane resin or the like can be used, and thus the intended annular gas filter F with a sharp tip can be obtained.

FIG. 5 shows an example of use in which the gas filter F of the present invention is incorporated in a gas generator for an automobile airbag. In the figure, (15) is a casing, and the outer and inner gas filters F, F are loaded on both sides of a partition (16) inside thereof. An ignition agent (18) is provided inside the ignition chamber (17), and when ignited, an explosive such as sodium azide (Na ₂ N) in the explosive chamber (19) burns explosively. A large amount of high-temperature gas (nitrogen gas) is generated, and while this high-temperature gas sequentially passes through the inner and outer gas filters F, F filled in the lower part, harmful components in the gas are removed and the high-temperature gas is cooled. And are done. Then, the appropriately cooled gas is supplied to a gas utilization side such as an airbag.

(Effect of the Invention) Since the gas filter of the first invention manufactured by the method of the present invention is formed by compression molding a loop group of metal wire rods that are bent in different gear tooth shapes of modules in different directions. The metal wires are intimately entangled with each other, are homogeneous, and have a structure in which it is difficult to form a gas short path path. Moreover, since this gas filter has an appropriate elasticity, it can be easily loaded into the casing, and no gap is formed between the gas filter and the casing. Furthermore, since this gas filter is compression-molded into an annular shape while being fastened by a fastening wire rod that has been bent around the loop group, it has good shape retention before compression molding and dimensional accuracy without burr on the surface. It can be molded in a high state. Therefore, the gas filter F of the present invention can completely prevent a short path of high temperature gas during use. In addition, it is easy to process thick wire and does not burn easily, and it can withstand long-term use. Furthermore, the metal wires can be easily manufactured by bending the metal wire rods in different directions into different gear tooth shapes of different modules, then forming loop groups, and then compression molding. It is a thing.

Further, according to the method of manufacturing the gas filter of the second invention, the gas filter having the above-mentioned excellent characteristics can be manufactured easily and efficiently. In particular, because a combination of two types of gears with different modules was used for processing the metal wire,
It is possible to perform a bending process suitable for use as a gas filter on a metal wire at a high speed. In addition, since a winding wire is wound around the drum in this way to form a loop group, and a winding wire around which the bending wire is bent is wound and fastened in a predetermined shape to perform compression molding. Not only can it be easily inserted into the mold, but the precision and surface condition of the compression molded product can be significantly improved.
A method in which the loop group is preformed, fastened, and then compression-molded is also conceivable. However, no particular effect is obtained by this preforming, and the manufacturing method of the present invention in which preforming is omitted from the viewpoint of cost. Is preferred.

As described above, the present invention is a gas filter that solves the conventional problems and a method for manufacturing the same, and thus can be used as, for example, a gas filter or a spring material used in a gas generator for an automobile airbag, etc. The areas that contribute to the development of industry are extremely large.

[Brief description of drawings]

Each of the drawings shows an embodiment of the present invention. FIG. 1 is a perspective view showing a bending process of a metal wire rod, FIG. 2 is a perspective view showing a state in which a loop group is fastened by a fastening wire rod, and FIG.
4 and 5 are cross-sectional views showing a compression molding process, and FIG. 5 is a cross-sectional view showing a usage state of the gas filter of the present invention. (1): Metal wire, (2): First gear, (4): Second gear, (5): Loop group, (6): Fastening wire, (11),
(13): Mold.

Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location B64D 25/00 8816-3D

Claims (2)

[Claims] 1. A loop group (5) of metal wire rods (1) bent in different directions in different gear tooth shapes of modules in respective directions is surrounded by fastening wire rods (6) bent. A gas filter, wherein the gas filter is in a state of being compression-molded in an annular shape in a state of being fastened. 2. A metal wire rod (1) is attached by a first gear (2) to
Direction and then bent in a different direction by the second gear (4) with a different module to form a gear tooth shape, which is wound on a drum to form a loop group (5), and its surroundings. The fastening wire rod (6) that has been bent is wound around and fastened to a predetermined shape, and the annular mold (11),
(13) A method for manufacturing a gas filter, which comprises storing the gas filter in the inside and performing compression molding.