Filter and gas generator

Abstract

The present application provides a filter and a gas generator. Even in the event of a metal wire breakage, the metal wire is prevented from coming off or the coming off of the metal wire is limited to a very small local range, so as not to affect other parts of the metal wire. The filter (201) has a winding body (210A) wound in a spiral and multiple layers by a metal wire (220), and at least one protection member (231) covering a part of the outer peripheral surface of the winding body for preventing the coming off of the metal wire. The winding body has a low turn number portion (211) at the outer peripheral portion including the outermost layer (Ln) thereof, and the number of turns of the metal wire is less than that of the inner peripheral portion (213). The protection member is composed of a separate member different from the metal wire. The protection member is installed at the middle portion in the axial direction of the winding body and wound around the winding body by at least one turn. One portion (contact portion (221)) of at least the first metal wire portion (220(n)) constituting the outermost layer of the winding body contacts the protection member.

Description

Technical Field

[0001] This invention relates to a filter and a gas generator. Background Technology

[0002] Airbags are installed in vehicles such as automobiles to protect occupants from the impact of collisions. In the event of a collision, a gas generator causes the airbag to inflate and deploy instantaneously. The gas generator contains a built-in metal filter to control and cool the high-temperature gas generated by the combustion of the gas.

[0003] As an example of the aforementioned metal filter, Patent Document 1 describes a wound-type filter, which is formed by spirally and in multiple layers of at least one metal wire. This filter is cylindrical and has anti-unraveling portions at both ends in the axial direction. The winding density of the metal wire is increased by reducing the winding spacing. This suppresses unraveling near the axial ends and improves the filter's shape retention.

[0004] Existing technical documents Patent documents Patent Document 1: Japanese Patent Application Publication No. 2007-319781 Summary of the Invention

[0005] The technical problem that the invention aims to solve In Patent Document 1, the anti-split section is formed of metal wire constituting the filter. Therefore, when a metal wire breaks in or near the anti-split section, the anti-split section will detach and fail to function. As a result, the filter portion located on the inner diameter side of the anti-split section may detach.

[0006] The present invention was made in view of the above circumstances, and its object is to prevent the metal wire from detaching or to limit the detachment of the metal wire to a very small local area so as not to affect other parts of the metal wire, even in the event of a breakage of the metal wire.

[0007] Technical solutions for solving technical problems To solve the aforementioned technical problems, the present invention provides a filter comprising: a winding body formed by spirally and in multiple layers of metal wire; and at least one protective member covering a portion of the outer peripheral surface of the winding body to prevent the metal wire from unraveling. The winding body has a low-turn portion on its outermost peripheral portion, where the number of turns of the metal wire is less than that on the inner peripheral portion. The protective member is composed of an independent component different from the metal wire and is installed at an appropriate position on the winding body. At least one portion of the first metal wire portion constituting the outermost layer of the winding body contacts the protective member.

[0008] Invention Effects According to the present invention, even in the event of a wire breakage, the wire is prevented from detaching or the detachment is limited to a very small local area so as not to affect other parts of the wire. Attached Figure Description

[0009] Figure 1 The figures illustrate the filter according to the first embodiment of the present invention, (a) being a schematic perspective view of the filter, and (b) being a schematic perspective view of the winding body constituting the filter.

[0010] Figure 2 This is a schematic diagram illustrating the manufacturing method of the winding body.

[0011] Figure 3 This is a schematic diagram of a disc-shaped gas generator assembled with a filter according to an embodiment of the present invention.

[0012] Figure 4 (a) and (b) are top views illustrating an example of an installation method for a protective component that is wound circumferentially.

[0013] Figure 5 (a) and (b) are schematic front views illustrating the installation location of the protective components.

[0014] Figure 6 This is a schematic front view illustrating the number of turns in the metal wire belonging to the low-turn section.

[0015] Figure 7 (a) and (b) are schematic front views showing a variation of the first embodiment.

[0016] Figure 8 This is a schematic front view illustrating the filter according to the second embodiment of the present invention.

[0017] Figure 9 (a) and (b) are schematic front views illustrating the installation location of the protective components.

[0018] Figure 10 (a) and (b) are schematic front views showing a modified example of the second embodiment.

[0019] Figure 11 (a) and (b) are photographs showing the test specimens used to calculate the relationship between the protective component’s coverage of the outer periphery of the winding and the pressure loss.

[0020] Figure 12 Figures (a) and (b) are graphs showing the relationship between the coverage of the protective component on the outer periphery of the winding and the pressure loss. Detailed Implementation

[0021] The present invention will now be described in detail using embodiments shown in the accompanying drawings. However, unless otherwise specified, the structural elements, types, combinations, shapes, and relative arrangements described in these embodiments are merely illustrative examples and are not intended to limit the scope of the invention thereto. Furthermore, the various embodiments may be appropriately combined and implemented without contradiction.

[0022] [Brief Structure of the Filter] Figure 1 The figures illustrate the filter according to the first embodiment of the present invention, (a) being a schematic perspective view of the filter, and (b) being a schematic perspective view of the winding body constituting the filter.

[0023] The hollow cylindrical filter (hereinafter referred to as filter) 201A (201, 200) according to the embodiments of the present invention has: a hollow cylindrical winding body 210A (210) which is formed by winding one or more continuous metal wires 220 in a spiral, multi-layered manner and with adjacent metal wire portions in the inner and outer radial directions extending in mutually intersecting directions; and at least one protective member 231 (230) which covers a portion of the outer peripheral surface of the winding body for preventing the metal wires from detaching.

[0024] First, the general structure and manufacturing method of the winding body will be explained, as well as a gas generator as an example of a device equipped with a filter.

[0025] In one embodiment of the present invention, the winding body 210 is formed by winding at least one continuous metal wire 220 in a spiral and multi-layered manner with a certain inclination angle relative to the axial direction (vertical direction in the figure) and at a certain interval. Here, each layer of metal wire 220 wound in the same direction is referred to as wire layer L1, L2, L3... The metal wires constituting each wire layer L1, L2, L3... extend in the same direction inclined relative to the axial direction (central axis Ax1) of the hollow cylindrical winding body in the front view, and the metal wires constituting adjacent wire layers in the inner and outer diameter directions extend in mutually intersecting directions (not parallel).

[0026] Figure 1 The extension direction (length direction of the metal wire portion 220(n-2) constituting the wire layer Ln-2) (thickness omitted in the figure) is indicated by the solid arrow, and the extension direction (length direction of the metal wire portion 220(n-3) constituting the inner side of the wire layer Ln-3) is indicated by the dashed arrow.

[0027] That is, the winding body 210 has: a wire layer (e.g., wire layer L1) formed by spirally winding metal wire 220 at a certain angle relative to the axial direction; and another wire layer (e.g., wire layer L2) formed by spirally winding metal wire over the outer periphery of a wire layer L1 at a different angle than the metal wire constituting the wire layer L1. The metal wires constituting a wire layer L1 and the adjacent wire layer L2 are configured to be non-parallel to each other relative to the axial direction and intersect each other.

[0028] Alternatively, it can be configured such that, within a wire layer, the tilt angle of the metal wire constituting the wire layer relative to the axial direction changes.

[0029] Alternatively, it can be configured such that, as with wire layers Ln and Ln-1, the tilt angle of the metal wires 220(n) and 220(n-1) relative to the axial direction changes within a winding body 210.

[0030] The filter 200, including the winding body 210, is used to remove unwanted substances from various fluids such as liquids and gases, and simultaneously cools the fluid passing through the filter, depending on the application. Furthermore, the filter is configured such that a flow path for fluid passage is formed in the radial direction of the overlapping wire layers. Fluid can pass through from the inner diameter side to the outer diameter side of the filter, or from the outer diameter side to the inner diameter side. Here, radial refers to approximately radial direction relative to the axial and circumferential directions, rather than a strictly diametrical direction (radial direction).

[0031] The size of the filter (inner diameter, outer diameter, axial dimensions, etc.) can be appropriately determined according to the structure and size of the device assembling the filter.

[0032] The types of metals that can be used to make the winding body include iron, mild steel, stainless steel, nickel alloy, copper alloy, etc., with austenitic stainless steel (SUS304) being the preferred material.

[0033] Furthermore, the thickness and cross-sectional shape (the cross-sectional shape in the direction orthogonal to the length of the metal wire) of the winding body can be appropriately determined according to the size of the filter, the substances removed by the filter, pressure loss, etc. For example, the cross-sectional area of ​​the metal wire used for a gas generator filter is about 0.03 to 0.8 mm² (if a circular wire with a perfectly circular cross-section is used as a reference, the wire diameter is about 0.2 to 1 mm).

[0034] The metal wire used in the winding body is formed by rolling bare metal wire with a circular cross-section into a specified shape. As the metal wire, flat wire with a flat rectangular cross-section or irregularly shaped wire with a roughly V-shaped cross-section can be used. In the winding body 210, the metal wire 220 is wound in a manner that does not involve twisting.

[0035] [Manufacturing method of the winding body] Figure 2 This is a schematic diagram illustrating the manufacturing method of the winding body.

[0036] When manufacturing the winding body 210, firstly, one end (the starting end, the beginning of winding) of the metal wire 220 is positioned appropriately on the mandrel 131 constituting the winding device 130. While applying a predetermined tension to the metal wire 220, the mandrel 131 is rotated in a predetermined direction at a predetermined speed around the central axis Ax2, and the guide member 132 supplying the metal wire 220 reciprocates along the central axis Ax2 of the mandrel 131 at a predetermined speed. Through this action, the metal wire 220 is wound in a spiral and multi-layered manner around the outer periphery of the mandrel 131. Furthermore, the metal wires constituting adjacent wire layers intersect each other to form a mesh.

[0037] For example, in the first metal wire layer directly wound around the outer periphery of the core rod 131, when each metal wire 220 is tilted at a predetermined angle θ in the clockwise direction relative to the axial direction of the core rod 131, the metal wire 220 constituting the second metal wire layer wound around the outer periphery of the first metal wire layer is tilted at a predetermined angle θ in the counterclockwise direction relative to the axial direction of the core rod 131.

[0038] The starting end of the metal wire 220, which is held on one end side of the mandrel 131 (right side in the figure), is folded back to the other end direction of the mandrel 131 (left side in the figure) when the metal wire 220 is wound around the mandrel 131 two or more times. The starting end is then further wound around by overlapping the folded-back starting end, securing it between adjacent wire layers. Afterward, the metal wire 220 is wound a predetermined number of turns (predetermined number of layers), and the other end (terminal portion, end of winding side) of the metal wire 220 is fixed to the appropriate position of the wound metal wire 220 by resistance spot welding. The welding machine 150 for resistance spot welding the metal wire 220 has an electrode 151 for flowing the current required for joining. The electrode 151 is configured to be able to move forward and backward relative to the mandrel 131, press the metal wire 220 with a predetermined pressure, and flow the joining current while pressed.

[0039] After joining the ends of the metal wire 220, the metal wire 220 is cut off by an appropriate method and removed from the core rod 131, thereby obtaining a hollow cylindrical body.

[0040] The angle (winding angle) of the metal wire 220 relative to the mandrel 131 and the spacing (pitch) between adjacent metal wires 220 along the axial direction can be changed by appropriately adjusting the ratio of the rotational speed of the mandrel 131 to the moving speed of the guide member 132. By appropriately changing the thickness of the metal wire, the winding angle, the pitch, and the number of winding turns, the pressure loss of the fluid passing through the filter (winding body) can be controlled to an appropriate value.

[0041] Furthermore, the mandrel 131 is generally cylindrical or cylindrical in shape and is usually made of metals such as stainless steel, copper alloy, or aluminum alloy. The inner diameter of the winding body 210 is equivalent to the outer diameter of the mandrel 131, and the outer diameter of the winding body 210 can be appropriately adjusted according to the thickness of the metal wire 220 and the number of turns.

[0042] The winding body 210 manufactured by the above method, after having a protective component 230 installed on its outer peripheral surface, is thus completed as a filter 200. No sintering treatment is performed on the entire filter.

[0043] [Gas generator for assembling filters] Figure 3 This is a schematic diagram of a disc-shaped gas generator assembled with a filter according to an embodiment of the present invention.

[0044] The disc-shaped gas generator 1 has a generally cylindrical outer shell that is closed at both axial ends (upper and lower ends in the figure). Within the internal accommodating space formed by the outer shell, there are internal structural components such as a retainer 30, an igniter 40, a cup-shaped component 50, a ignition propellant 59, a gas generating agent 61, a lower support component 70, an upper support component 80, a cushioning material 85, and a filter 200. Furthermore, within the internal accommodating space of the outer shell, there is a combustion chamber 60 that primarily houses the gas generating agent 61 from the aforementioned internal structural components.

[0045] The outer shell has a lower side shell 10 with an opening at the top (having an upper opening) and a generally bottomed cylindrical shape, and an upper side shell 20 with an opening at the bottom (having a lower opening). The lower side shell 10 and the upper side shell 20 are formed by stamping metal sheets made of stainless steel, steel, aluminum alloy, stainless steel alloy, etc.

[0046] With the upper opening facing the lower opening, the upper end of the lower side housing 10 is pressed into the lower end of the upper side housing 20, and the abutment portion or the vicinity of the two is joined by electron beam welding, laser welding or friction pressing, thereby making the two integrated.

[0047] The upper side housing 20 has a flange portion 25 that protrudes from its lower end edge in the outward diameter direction. The flange portion 25 is a part for fixing the disc-shaped gas generator 1 to the outside (e.g., a retainer provided in an airbag device).

[0048] A protruding cylindrical portion 13 protrudes from the center of the bottom plate portion 11 of the lower side shell 10 to the top plate portion 21 of the upper side shell 20. Consequently, a recessed portion 14 is formed on the outer side of the shell, opposite to the protruding cylindrical portion 13. An opening 15 is formed on the end face of the protruding cylindrical portion 13 on the top plate portion 21 side, allowing communication between the inside and outside of the shell.

[0049] A retaining portion 30 for fixing the igniter 40 is provided on the side of the protruding cylindrical portion 13 and the side of the recessed portion 14 via the opening 15. The retaining portion 30 is made of insulating resin and is formed by insert molding.

[0050] The igniter 40 is a flame-generating mechanism, comprising: an ignition part 41 containing an ignition powder and a resistor for igniting the ignition powder; and a pair of terminal pins 42 supplying power to the resistor. The resistor ignites the ignition powder by generating Joule heat. The recess 14 is a space for providing a female connector part 34 on the retaining part 30 that communicates with the terminal pins 42.

[0051] A cup-shaped component 50 is assembled on the base plate 11 to cover the protruding cylindrical portion 13, the retaining portion 30, and the igniter 40. A propellant 59 is housed within the hollow portion of the cup-shaped component 50.

[0052] When the ignition propellant 59 is ignited by the igniter 40, the cup-shaped component 50 may crack, deform, or melt due to the increased pressure in its internal space or the conduction of the generated heat.

[0053] Inside the outer casing, the space surrounding the cup-shaped component 50 is a combustion chamber 60 that houses the gas generator 61. The gas generator 61 is disposed adjacent to the outer surface of the cup-shaped component 50.

[0054] Within the space surrounding the combustion chamber 60 containing the gas generator 61 radially around the outer casing, a filter 200 according to an embodiment of the present invention is disposed along the inner periphery of the outer casing. The filter 200 has a cylindrical shape, and its central axis Ax1 is configured to substantially coincide with the axial direction of the outer casing.

[0055] When the gas generated by the combustion chamber 60 passes through the filter 200, it functions as a cooling mechanism to cool the gas by removing the heat from the gas due to its high temperature, and it also functions as a removal mechanism to remove residues (slag) contained in the gas. Furthermore, the filter 200 is separately disposed from the peripheral walls 12 and 22, which form a predetermined gap 28 between itself and the peripheral walls 12 and 22 of the lower side housing 10 and the upper side housing 20, which constitute the outer casing.

[0056] On the peripheral wall 22 of the upper side housing 20 opposite to the filter 200, a plurality of gas outlets 23 are provided. These gas outlets 23 are used to discharge gas passing through the filter 200 to the outside of the housing. Furthermore, sealing tape 24 is affixed to the gas outlets 23. The sealing tape 24 ensures the airtightness of the combustion chamber 60.

[0057] A ring-shaped lower support member 70 is disposed on the bottom plate portion 11 side inside the combustion chamber 60 to fix the filter 200 to the housing and to prevent the generated gas from flowing out through the gap between the lower end of the axial end of the filter 200 and the bottom plate portion 11. Similarly, a disc-shaped upper support member 80 is disposed on the top plate portion 21 side inside the combustion chamber 60 to fix the filter 200 to the housing and to prevent the generated gas from flowing out through the gap between the upper end of the axial end of the filter 200 and the top plate portion 21. The lower support member 70 and the upper support member 80 are formed by stamping or other processes on steel plates such as ordinary steel or special steel.

[0058] Between the upper support member 80 and the gas generator 61, a disc-shaped cushioning material 85 is disposed to press the gas generator 61 toward the base plate 11. The cushioning material 85 is made of rock wool or foamed resin, etc., and is used to prevent the gas generator 61 from breaking due to vibration or other reasons.

[0059] The gas generator 1 operates as follows: First, upon a vehicle collision, ignition 40 is activated by power from the control unit. The activation of ignition 40 initiates combustion of the propellant 59. The cup-shaped component 50 ruptures, and the gas generating agent 61 burns, producing a large amount of gas. The gas passes through the interior of the filter 200 and flows into the gap 28. As the internal pressure inside the housing increases, the sealing tape 24 sealing the gas outlet 23 ruptures, and gas is ejected to the outside of the housing through the gas outlet 23. The ejected gas inflates and deploys the airbag.

[0060] [First Implementation] based on Figure 1 The structure of the filter is described in detail.

[0061] like Figure 1 As shown in (b), the winding body 210A (210) has a low number of turns portion 211 on the outer periphery of the outermost wire layer (outermost layer) Ln of the multiple wire layers L formed by the metal wire 220. The number of turns p of the metal wire 220 in each wire layer L of the low number of turns portion 211 is less than the number of turns of the metal wire in each wire layer of the inner periphery portion 213 located inside the outer periphery.

[0062] like Figure 1 As shown in (a), the protective component 231 (230) is composed of independent components different from the metal wire 220. The protective component 231 is installed at an appropriate position on the winding body 210A, and at least one part (contact portion 221) of the metal wire portion 220(n) (first metal wire portion) constituting the outermost layer Ln of the winding body contacts the protective component 231.

[0063] <Winding Body> In this example, wire layers Ln and Ln-1 constitute the low-turn section 211, and wire layers Ln-2 to L1 constitute the inner peripheral section 213.

[0064] In the low-turn section 211, the number of turns (winding turns) of the metal wire 220 in each wire layer L is less than that in the inner peripheral section 213. That is, the low-turn section 211 includes a portion where the winding pitch is wider than that of each wire layer located in the inner peripheral section 213. Here, the winding pitch refers to the axial spacing of the metal wires 220 in each wire layer L.

[0065] The lower-circle section 211 is constructed by including at least the outermost layer Ln. For example... Figure 1As shown, the preferred low-turn section 211 is configured to include an outermost layer Ln and an adjacent wire layer Ln-1. The low-turn section 211 may contain three or more wire layers.

[0066] As the number of wire layers constituting the low-turn section 211 increases, the external shape of the winding body 210A becomes larger. Therefore, the number of wire layers constituting the low-turn section 211 is set to an optimal number based on the required strength and size of the winding body 210A. For example, the number of wire layers constituting the low-turn section 211 is set to approximately 1 to 10 layers.

[0067] The number of turns of the metal wire 220 in each wire layer constituting the low-turn section 211 will be explained later.

[0068] <Protective Components> In the event of a breakage in the metal wire section 220(n), the protective component 231 serves to prevent the metal wire 220 from detaching or to minimize the adverse effects caused by the detachment. Here, "detachment" refers to a phenomenon where the winding state of the metal wire becomes disordered, such as the metal wire lifting up or the metal wire winding loosening.

[0069] The metal wire portion located on the inner periphery is pressed and fixed by the metal wire portion located on its outer periphery. Therefore, the metal wire portion located on the inner periphery 213 (inner than the outermost outer periphery) will not detach even if the metal wire portion 220(n) breaks. However, when the metal wire portion 220(n) itself breaks, it will detach by springing outwards. The protective member 231 suppresses such detachment of the metal wire portion 220(n).

[0070] The protective member 231 extends in a direction intersecting with the metal wire portions 220(n), 220(n-1). In this example, the protective member 231 is a strip-shaped or wire-shaped member extending in the circumferential direction. The protective member 231 is disposed at the middle of the axial direction of the winding body 210A and is wound around the winding body at least once.

[0071] The protective component 231 is installed as a portion of the winding body 210A that is entirely along (or attached to) the surface of the winding body. The protective component 231 intersects with the metal wire portion 220(n) at one point, and the intersecting portion is the contact portion 221 that contacts the metal wire portion 220(n).

[0072] The protective component 231 is configured such that when subjected to a force that causes the broken metal wire portion 220(n) to detach or to spring away (or to detach) in the outward direction, it will not detach from the winding body 210A, will not tilt, and will not break.

[0073] The protective component 231 may be made of the same material as the metal wire 220, or it may be made of a different material. Preferably, the protective component 231 has higher strength and higher rigidity than the metal wire 220.

[0074] The protective member 231 is mounted to the winding body 210A in a manner that enables it to prevent detachment. For example, at least a portion of the protective member 231 may be securely fixed (engaged) to the winding body 210A. Alternatively, the protective member 231 may be fixedly mounted to the winding body 210A by means of friction. The protective member 231 is mounted to the winding body 210A by a suitable method depending on the material it is made of.

[0075] The more engagement points the protective component 231 has with the winding body 210A, the more advantageous it is in improving the protective function of the protective component for the winding body. The strength and rigidity of the protective component 231 itself and the number of engagement points between the protective component and the winding body 210A are set according to the relationship between the two to enable the protective component to perform the required protective function (protective effect).

[0076] Furthermore, as long as the protective component 231 does not detach from the winding body 210A, the protective component and the metal wire portion 220(n) only need to be in contact, and the two do not necessarily need to be joined.

[0077] Preferably, the area (coverage area) of the outer peripheral surface of the winding body 210A covered by the non-porous portion of the protective component 231 is 30% or less of the outer peripheral surface of the winding body. The basis for setting it to 30% or less will be explained later.

[0078] <<Material examples>> <<<Metallic Materials>>> The protective component 231 may be made of a metallic material. In the case of a metallic material, the protective component 231 may be made of materials such as iron, mild steel, stainless steel, nickel alloy, or copper alloy, which are suitable for the winding body 210.

[0079] The protective component 231 can take various shapes.

[0080] The protective component can be made of a non-perforated steel plate. Alternatively, the protective component can have multiple holes. In this case, the protective component can be made of expanded metal mesh or perforated metal mesh. Furthermore, the protective component can be made of metal mesh such as textiles, woven fabrics, or non-woven fabrics.

[0081] The protective component 231 can also be a wire. When the linear protective component 231 is made of the same metal material as the metal wire 220, the required strength and rigidity of the protective component can be ensured, for example, by making the cross-sectional area of ​​the protective component larger than that of the metal wire 220.

[0082] The protective component 231, made of metal, can be joined (fixed) to the winding body 210A by welding or bonding. The protective component 231 can be joined to the winding body 210A using resin adhesives, bonding agents, or by brazing or soldering.

[0083] When the protective component 231 is a linear metal component, the protective component can be installed on the winding body 210A by twisting and fixing the two ends of the protective component in the length direction after winding the protective component around the winding body 210A.

[0084] <<<Resin Materials>>> The protective components can be made of resin materials such as silicone-based materials and acrylic-based materials. Protective components made of resin materials are bonded to the winding body using adhesives or bonding agents.

[0085] <<<The bonding agent itself>>> The protective component can be the adhesive itself that bonds to the winding body 210A. For example, the protective component 231 can be a resin-based adhesive raised on the winding body 210A, brazing filler metal soldered on the winding body 210A, or solder tin-bonded on the winding body 210A. Alternatively, the protective component can be the adhesive itself that can adhere to the winding body 210A. As the adhesive, for example, a silicone-based or acrylic adhesive with a specified thickness can be used.

[0086] <<Installation Method>> Figure 4 (a) and (b) are top views illustrating an example of the installation method of a protective component wound circumferentially. The direction perpendicular to the plane of the paper in the figures is the axial direction of the winding body 210A. Figure 4 Indicates will Figure 1 The example shown in (a) is a wire or strip-shaped protective component wound around a winding body. The following explanation will focus on the case where the protective component is made of metal.

[0087] For example, such as Figure 4 As shown in (a), one end 231a of the protective member 231 in the longitudinal direction is spot-welded to a suitable position in the circumferential direction of the winding body 210A. Next, the protective member 231 is wound circumferentially around the winding body 210A. Figure 4 As shown in (b), the other end 231b of the protective member 231 along its length is overlapped with one end of the protective member 231 along its length. The two ends of the protective member 231 along its length are joined together by spot welding. The positions of the two spot welds are adjusted so that they do not overlap radially.

[0088] The other end 231b of the protective member 231 in the longitudinal direction may not overlap with the protective member 231 in the radial direction. For example, the other end 231b of the protective member 231 in the longitudinal direction may be engaged with the winding body 210A. In this case, each end 231a, 231b of the protective member 231 is engaged with the metal wire portion from the third layer onwards (wire layers Ln-2, ​​Ln-3...) from the outer periphery of the winding body 210A. Even in this case, the protective member 231 has a portion in the longitudinal direction whose circumferential position overlaps with that of another portion in the axial direction. That is, the protective member 231 is wound around the winding body 210A in at least one turn.

[0089] The protective component 231 can be fixed to the winding body 210A at its middle portion along its length. The protective component 231 can also be fixed to multiple portions along its length of the winding body 210A.

[0090] <<Installation Location>> Figure 5 (a) and (b) are schematic front views illustrating the installation position of the protective component. Furthermore, in the figures, as belonging to the lower coil section 211 (see reference...) Figure 5 The metal wires are shown only in the outermost layer Ln (the first metal wire portion) and the adjacent layer Ln-1 (the second metal wire portion). The metal wire portions 220(n) and 220(n-1) are wound approximately evenly along the axial direction of the winding body 210A at a certain interval.

[0091] The protective member 231 is preferably configured to overlap with the intersection 222 of the metal wire portion 220(n) and the metal wire portion 220(n-1). In this case, the metal wire portion 220(n) contacts the protective member 231 at the intersection 222.

[0092] When the filter 201 has a protective member 231, it is preferable to set the number of turns of the metal wire 220 belonging to the low-turn section to one turn or less. In particular, it is preferable that the metal wire portions 220(n) and 220(n-1) are wound in a manner that crosses at the center or periphery of the winding body 210A in the axial direction. In this case, the protective member 231 is disposed at the center or periphery of the winding body 210A in the axial direction and overlaps at the intersection 222 of the metal wire portions 220(n) and 220(n-1).

[0093] Thus, regardless of whether the metal wire portion 220(n) breaks off at one end axially closer to the protective member 231 (cross portion 222) or at the other end, the length of the loosened metal wire 220 is always the same. This means that the length of the loosened metal wire 220 can be minimized. That is, in this example, this means that the length of the loosened metal wire 220 can be less than one circumference.

[0094] For example, such as Figure 5 As shown in (b), suppose that a break 223 occurs in the metal wire portion 220(n) of the winding body portion 210a, which is located axially closer to the end of the winding body than the protective member 231. In this case, the loosened portion 220a of the metal wire remains within the winding body portion 210a and does not affect the winding body portion 210b, which is located axially closer to the other end of the winding body than the protective member 231. The length of the loosened metal wire 220 is less than one turn. The same applies when a break occurs in the winding body portion 210b.

[0095] Figure 6 This is a schematic front view illustrating the number of turns in the metal wire belonging to the low-turn section.

[0096] The reason for setting the number of turns of the metal wire 220 belonging to the low-turn section 211 to "less than one turn" is as follows: The end portion 224 of the metal wire 220 is typically fixed to a suitable position on the winding body 210A by spot welding. The spot welding position is selected from any position of the wound metal wire 220. Therefore, even if the metal wire portion 220(n) is wound at a spacing and angle that allows for one full turn, the actual number of turns of the metal wire portion 220(n) will not reach one full turn. For example, when the metal wire portion 220(n) is welded to the central portion of the winding body 210A along its axial direction, the length of the metal wire portion 220(n) is 0.5 turns. Based on this, the number of turns of the metal wire 220 belonging to the low-turn section 211 is specified as "less than one turn".

[0097] <Variation Example> Figure 7 (a) and (b) are schematic front views illustrating a variation of the first embodiment. Figure 7 In (a) and (b), the explanation is based on the premise that the number of turns of the metal wire portion 220(n-1) (not shown) is the same as that of the metal wire portion 220(n).

[0098] exist Figure 1 and Figure 7In the filter 201 (201A to 201C) shown, the number of protective components 231 is set to satisfy the following condition: When the number of turns of the outermost metal wire portion 220(n) of the outermost Ln is set to p (where p is a positive number) and the number of protective components is q (where q is a natural number), p ≤ q is satisfied. Furthermore, in the filter 201, the number of contact portions 221 is r = q.

[0099] As shown in filters 201B and 201C, filter 201 may also have multiple protective components 231 (231A to 231C).

[0100] Figure 7 Example (a) shows an example where the number of turns relative to the metal wire portion 220(n) is p=1, and the number of protective members 231 is q=3. Preferably, at least one protective member 231B overlaps at the intersection 222 of the metal wire portion 220(n) and the metal wire portion 220(n-1) (not shown). However, if the number of protective members q is greater than the decimal part of the number of turns q, even if the protective members do not overlap at the intersection 222, the length of the metal wire 220 that may loosen is less than one turn.

[0101] Figure 7 (b) is an example where the number of turns of the metal wire portion 220(n) is p=3 and the number of protective members 231 is q=3. By making the number of turns q rounded up from the decimal point the same as the number of protective members q, and by overlapping the protective members at the intersection 222, the length of the metal wire 220 that may loosen is less than one turn.

[0102] In the case where the filter 201 has multiple protective components 231, the axial spacing of the protective components is set such that the length of the metal wire 220 that may loosen is less than the required length (e.g., less than one circumference).

[0103] [Second Implementation] Figure 8 This is a schematic front view illustrating the filter according to the second embodiment of the present invention.

[0104] The filter 202A (202, 200) has a winding body 210B (210) and a protective member 232 (230). The winding body 210B shown in the figure differs from that in the first embodiment in that the low number of turns section 211 ( Figure 1 Furthermore, the winding body of the filter according to this embodiment can also be... Figure 1 The winding body 210A shown is shown.

[0105] Similar to the first embodiment, the protective component 232 is composed of a separate component that is different from the metal wire 220. Furthermore, it is preferable that the protective component 232 has higher strength and rigidity than the metal wire 220, and the material used for the protective component 232 is the same as in the first embodiment.

[0106] The protective component 232 differs from that in the first embodiment in that it is not wound around the winding body 210B.

[0107] In this example, it is also preferable that the area (coverage area) of the outer peripheral surface of the winding body 210B covered by the non-porous portion of the protective member 232 is 30% or less of the outer peripheral surface of the winding body. The basis for setting it to 30% or less will be explained later.

[0108] Hereinafter, the same reference numerals will be used for structures that are the same as those in the first embodiment, and descriptions will be omitted as appropriate. The differences from the first embodiment will be mainly described.

[0109] <Protective Components> In filter 202A, protective component 232 is disposed at a circumferential location on winding body 210B and fixed at an appropriate position on winding body 210B.

[0110] The protective member 232 extends in a direction intersecting the metal wire portion 220(n). In this example, the protective member 232 is an axially extending strip that intersects the metal wire 220. The protective member 232 covers the winding body 210B on a portion of its circumferential direction.

[0111] When the filter 202A has a single protective member 232, the length of the protective member 232 is set to span across the portion of the metal wire portion 220(n) that can overlap with the protective member 232, specifically the portion located at the farthest end in the axial direction (contact portion 221A) and the portion located at the farthest end in the axial direction (contact portion 221C). For example, the protective member 232 can extend over the entire axial length of the winding body 210B.

[0112] <<Installation Location>> Figure 9 (a) and (b) are schematic front views illustrating the installation location of the protective component. Furthermore, in the metal wire section, Figure 9 (a) shows only the metal wire portion 220(n), and (b) shows only the metal wire portions 220(n) and 220(n-1).

[0113] The filter 202A is configured such that when the number of turns of the metal wire portion 220(n) constituting the outermost layer Ln of the winding body 210B is set to p (where p is a positive number) and the number of contact portions 221 that contact the metal wire portion 220(n) with the protective member 232 is r (where r is a natural number), p≦r is satisfied.

[0114] In this example, where the number of turns of the metal wire portion 220(n) is p=3, the metal wire portion 220(n) has multiple contacts 221 (221A~221C) with a number of r=3.

[0115] By setting it up in this way, such as Figure 9 As shown in (b), even if the metal wire portion 220(n) breaks at any point, the length of the metal wire 220 that may be loosened is less than one revolution length.

[0116] exist Figure 9 (b) shows a case where a wire break 223A occurs at the end closer to the axial direction than contact 221A, and a wire break 223B occurs between contact 221B and contact 221C. In either case, only the metal wire 220 between contact 221, 221 is loosened, and the length of the loosened portions 220a, 220b of the metal wire is less than one revolution.

[0117] In this example, the protective member 232 is a strip extending axially, and its length is approximately equal to the axial length of the winding body 210B. Therefore, each contact portion 221 is located in the same circumferential portion and is separated axially. In addition, all contacts 221A to 221C are located on a single protective member 232.

[0118] In addition, such as Figure 9 As shown in (b), similar to the first embodiment, the protective member 232 is preferably configured to contact the metal wire portion 220(n) at the intersection 222. With this configuration, it is possible to control the length of the loosened metal wire so that whether the metal wire portion 220(n) breaks off at the end closer to the axial direction than the intersection 222 or at the other end, the length of the loosened metal wire will not differ significantly.

[0119] <<Installation Method>> The protective component 232 is fixed relative to the winding body 210B using a method suitable for the shape of the protective component 232 as described in the first embodiment.

[0120] The protective component 232 is fixed to the winding body 210B in such a way that in the event of a breakage in the metal wire portion 220(n), the protective component 232 will not detach from the winding body 210B together with the metal wire portions 220(n) and 220(n-1).

[0121] The illustrated filter 202A has three joints 233A to 233C, with joint 233 serving as the joint between the protective member 232 and the winding body 210B. Joint 233 is, for example, a spot welded portion. Two joints 233A and 233C are located at both ends of the protective member 232 along its length. Joint 233B is located at an appropriate position between joints 233A and 233C.

[0122] In order to perform the required function, the protective component 232 is fixed to the winding body in a manner that does not create a large gap between it and the outer peripheral surface of the winding body 210B.

[0123] Therefore, when the protective member 232 is located along the entire axial length of the winding body 210B, i.e., when the length of the protective member 232 is relatively long, it is preferable that the joint portion 233 is provided at least once at each end of the protective member 232 along its length. In this case, the required number of joint portions 233 are provided in the middle of the length direction, depending on the length of the protective member 232 (or the axial length of the winding body 210B).

[0124] <Variation Example> Figure 10 (a) and (b) are schematic front views showing a modified example of the second embodiment.

[0125] The filter 202 (202B, 202C) may have multiple protective components 232 (232A to 232C). In addition, the protective components 232 may be shorter than the total axial length of the winding body 210B.

[0126] Figure 10 Example (a) shows an example where the number of turns of the metal wire portion 220(n) is p=3, resulting in a number of protective components 232 of q=3. Each protective component 232A to 232C has one contact portion 221 (221A to 221C). The total number of contact portions 221 of the filter 202B is r=3, satisfying p≦r.

[0127] Each protective component 232 is configured to have at least one contact portion 221 on each periphery of the metal wire portion 220(n). That is, each protective component 232 is configured such that two adjacent contact portions 221, 221 are spaced within one periphery of each other. In addition, each protective component 232 is configured such that each contact portion 221 is axially separated.

[0128] Figure 10Example (b) shows an example where the number of turns of the metal wire portion 220(n) is p=3, resulting in q=2 of the number of protective components 232. Each protective component 232A and 232B has two contact portions 221. The filter 202C has a total of r=4 contact portions 221 (221A to 221D), satisfying p≦r.

[0129] Each protective component 232 is configured such that the interval between two adjacent contact portions 221, 221 is within one circumference. For example, protective components 232A, 232B are configured such that the interval between two adjacent contact portions 221B, 221C is within one circumference. In addition, each protective component 232A, 232B is configured such that the contact portions 221 are separated in the axial direction.

[0130] exist Figure 10 In (a) and (b), each protective component 232 has two joints 233, but the number of joints in a single protective component is not limited to this. For example, Figure 10 The protective component 232 shown in (a) is relatively short, so only one joint 233 can be provided on the metal wire portion 220(n).

[0131] [Basis for Coverage Rate] Figure 11 (a) and (b) are photographs showing the test specimens used to calculate the relationship between the protective component’s coverage of the outer periphery of the winding and the pressure loss.

[0132] Test specimens 240 (240A, 240B) are formed by covering the outer surface of the winding body 210B with an aluminum-based adhesive tape 241 (241A, 241B). The adhesive tape 241 does not have any holes passing through its surface (holes connecting the inner diameter side and the outer diameter side facing the winding body 210B), and has a porosity of 0%.

[0133] Figure 11 The test specimen 240A shown in (a) is formed by winding tape 241A around the central portion of the winding body 210B in the axial direction. Tape 241A covers the entire circumference of the winding body 210B.

[0134] Figure 11 The test specimen 240B shown in (b) is formed by attaching tape 241B at appropriate positions in the circumferential direction of the winding body 210B. The tape 241B extends along the axial direction of the winding body 210B and covers the entire axial direction of the winding body 210B.

[0135] When the width of tape 241 is increased, the coverage area expands axially (height direction) in test body 240A, and expands circumferentially in test body 240B. For each test body 240, pressure loss is measured with different tape widths (coverage rates), and the relationship between the coverage rate (sealing rate) of the outer surface of the winding body 210B and pressure loss is determined.

[0136] Figure 12 Figures (a) and (b) are graphs showing the relationship between the coverage of the protective component on the outer periphery of the winding and the pressure loss. Figure 12 (a) corresponds to test subject 240A. Figure 12 (b) corresponds to test subject 240B. Each figure shows the data and graphs that form the basis of the curves. The dashed lines in the figures are approximate straight lines when the coverage is 0-30%.

[0137] The outer diameter (diameter) of the winding body 210B constituting each test body 240 is 53 mm, the height (axial length) is 49 mm, and the outer circumferential area is 8159 mm². Furthermore, the pressure loss of the winding body at 0% coverage is 0.42 kPa.

[0138] The "Pressure Loss Increase Rate" in the table is "{Pressure loss when coverage is x% - Pressure loss when coverage is (x-10%)} / Pressure loss when coverage is (x-10%)".

[0139] like Figure 12 As shown, the relationship between coverage and pressure loss is roughly the same in test specimens 240A and 240B.

[0140] like Figure 12 As shown in graphs (a) and (b), the pressure loss increases approximately linearly before the coverage reaches 30%. When the coverage exceeds 30%, the graph becomes non-linear, and the rate of increase in pressure loss rises sharply.

[0141] Based on the above results, in this invention, to prevent a sharp increase in pressure loss, it is preferable that the coverage of the winding body 210 (210A, 210B) is within 30%. Furthermore, the coverage of the protective component over the winding body must take into account the porosity of the protective component (or the pressure loss of the protective component). That is, it is preferable that the coverage of the non-porous portion of the protective component over the winding body is set to 30% or less of the outer circumferential area of ​​the winding body. By determining the coverage of the protective component over the winding body based on the pressure loss of the filter, it is possible to suppress the power loss of the propellant when using a filter with a protective component in a gas generator.

[0142] [Examples of embodiments of the present invention and a summary of their functions and effects] <First Implementation Method> The filter 201 involved in this method has: a winding body 210A, which is formed by spirally and multi-layered winding of metal wire 220; and at least one protective member 231, which covers a portion of the outer peripheral surface of the winding body for preventing the metal wire from detaching.

[0143] The winding body has a low-turn portion 211 on the outer periphery of the outermost layer Ln containing the winding body, where the number of turns of the metal wire is less than that of the inner periphery 213. The protective member is composed of a separate component different from the metal wire and is installed at an appropriate position on the winding body. The filter is characterized in that at least one portion (contact portion 221) of the first metal wire portion 220(n) constituting the outermost layer of the winding body is in contact with the protective member.

[0144] According to this method, since a protective component consisting of parts independent of the metal wire is installed on the outermost layer of the winding body, even in the event of a breakage of the metal wire, it is possible to prevent the metal wire from detaching or to limit the detachment of the metal wire to a very small local area so that it does not affect other parts of the metal wire.

[0145] In addition, since the number of turns of the metal wire is reduced in the outer periphery, even if the metal wire breaks in the low-turn section, the length of the detached metal wire can be limited to a minimum.

[0146] <Second Implementation Method> In the filter 201 involved in this method, the protective member 231 is disposed at the middle part of the axial direction of the winding body 210A and is wound around the winding body at least once.

[0147] The protective component can be a component that extends circumferentially along the winding body.

[0148] <Third Implementation Method> The filter 201 involved in this method is characterized in that when the number of turns of the first metal wire portion 220(n) is p (where p is a positive number) and the number of protective components 231 is q (where q is a natural number), p≦q is satisfied.

[0149] According to this method, the length of detached metal wire can be limited to less than one week.

[0150] <Fourth Implementation Method> In the filter 201 involved in this method, the metal wire 220 in the outermost layer Ln and its adjacent layer Ln-1 has less than one turn.

[0151] According to this method, the length of detached metal wire can be limited to less than one week.

[0152] <Fifth and Ninth Implementation Methods> In the filter 200 involved in this method, the non-porous portion of the protective member 230 covers the winding body 210 with an area of ​​less than 30% of the outer peripheral area of ​​the winding body.

[0153] According to this method, a sharp increase in pressure loss due to the presence of protective components can be avoided.

[0154] <Sixth Implementation Method> The filter 202 involved in this method has: a winding body 210B, which is formed by spirally and multi-layered winding of metal wire 220; and at least one protective member 232, which covers a portion of the outer peripheral surface of the winding body for preventing the metal wire from detaching.

[0155] The protective component is composed of a separate part that is different from the metal wire, and is located at a part around the circumference of the winding body and fixed at an appropriate position on the winding body.

[0156] The filter is characterized in that when the number of turns of the first metal wire portion 220(n) constituting the outermost layer Ln of the winding body is p (where p is a positive number) and the number of contact portions 221 that contact the first metal wire portion with the protective component is r (where r is a natural number), p≦r is satisfied.

[0157] According to this method, since a protective component consisting of parts independent of the metal wire is installed on the outermost layer of the winding body, even in the event of a breakage of the metal wire, it is possible to prevent the metal wire from detaching or to limit the detachment of the metal wire to a very small local area so that it does not affect other parts of the metal wire.

[0158] In addition, it can limit the length of detached metal wire to less than one week.

[0159] <Seventh Implementation Method> In the filter 202 involved in this method, the first metal wire portion 220(n) has a plurality of contact portions 221, each contact portion being axially separated.

[0160] According to this method, the length of the detached metal wire can be limited to less than one circumference. Furthermore, multiple contacts can be formed between the first metal wire portion and a single protective member, or between the first metal wire portion and multiple protective members.

[0161] <Eighth Implementation Method> In the filter 202 involved in this method, the protective member 232 extends in a direction intersecting with the first metal wire portion 220(n) and has a plurality of contact portions 221.

[0162] According to this method, the filter is easy to manufacture because the number of protective components can be reduced.

[0163] <Tenth Implementation Method> The feature of this method is a gas generator 1 assembled with the filters 200 of the above embodiments.

[0164] The gas generator described in this method can achieve the same effect as the filters described in the above embodiments.

[0165] Explanation of reference numerals in the attached figures L, L1, L2...Ln: Wire layer; Ln: Outermost layer; Ax1: (Filter) Central shaft; Ax2: (Core rod) Central shaft; 1: (Disc-type) Gas generator; 10: Lower side shell; 11: Base plate; 12: Peripheral wall; 13: Protruding cylindrical part; 14: Recess; 15: Opening; 20: Upper side shell; 21: Top plate; 22: Peripheral wall; 23: Gas outlet; 24: Sealing tape; 25: Flange 28: Gap section; 30: Holding section; 34: Female connector section; 40: Igniter; 41: Ignition section; 42: Terminal pin; 50: Cup-shaped component; 59: Propellant; 60: Combustion chamber; 61: Gas generator; 70: Lower support component; 80: Upper support component; 85: Buffer material; 130: Winding device; 131: Core rod; 132: Guide component; 150: Welding machine; 151: Electrode; 200: Filter; 201, 201A~C: Filters; 202, 202A~C: Filters; 210, 210A, 210B: Winding body; 210a, 210b: Parts of the winding body; 211: Low-turn section; 213: Inner circumference section; 220: Metal wire; 220(n): (First) metal wire section; 220(n-1): (Second) metal wire section; 220a, 220b: Unwinding section; 221, 221A~2 21C: Contact part; 222: Crossing part; 223, 223A, 223B: Broken wire; 224: Terminal part; 230: Protective component; 231, 231A~C: Protective component; 231a: One end; 231b: The other end; 232, 232A, 232B: Protective component; 233, 233A~C: Joint part; 240, 240A, 240B: Test piece; 241, 241A, 241B: Adhesive tape.

Claims

1. A filter comprising: a winding body formed by spirally and in multiple layers of metal wire; and at least one protective member covering a portion of the outer peripheral surface of the winding body for preventing the metal wire from unraveling, the filter being characterized in that... The winding body has a low-turn portion on its outermost periphery, where the number of turns of the metal wire is less than that on the inner periphery. The protective component is composed of a separate part, distinct from the metal wire, and is installed at an appropriate position on the winding body. At least one portion of the first metal wire portion constituting the outermost layer of the winding body is in contact with the protective component.

2. The filter according to claim 1, characterized in that, The protective component is disposed at the middle of the axial direction of the winding body and is wound around the winding body at least once.

3. The filter according to claim 1, characterized in that, When the number of turns of the first metal wire section is p and the number of the protective components is q, p ≦ q, where p is a positive number and q is a natural number.

4. The filter according to claim 1, characterized in that, The number of turns of the metal wire in the outermost layer and its adjacent layers is less than one.

5. The filter according to claim 1, characterized in that, The non-porous portion of the protective component covers less than 30% of the outer circumferential area of ​​the winding.

6. A filter comprising: a winding body formed by spirally and in multiple layers of metal wire; and at least one protective member covering a portion of the outer peripheral surface of the winding body for preventing the metal wire from unwinding, characterized in that... The protective component is composed of a separate part, distinct from the metal wire, and is disposed at a location on the circumference of the winding body, and fixed at an appropriate position on the winding body. When the number of turns of the first metal wire portion constituting the outermost layer of the winding body is p, and the number of contact portions between the first metal wire portion and the protective component is r, p≦r is satisfied, where p is a positive number and r is a natural number.

7. The filter according to claim 6, characterized in that, The first metal wire portion has a plurality of the contact portions, which are axially separated.

8. The filter according to claim 6, characterized in that, The protective component extends in a direction intersecting with the first metal wire portion and has a plurality of the contact portions.

9. The filter according to claim 6, characterized in that, The non-porous portion of the protective component covers less than 30% of the outer circumferential area of ​​the winding.

10. A gas generator, characterized in that, The filter is assembled with any one of claims 1 to 9.

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