Filter, method for manufacturing a filter, and gas generator

Abstract

An object of the present application is to make a portion of a metal wire after joining less likely to be hooked to other members or the like. A filter (200) in a hollow cylindrical shape is formed by winding one or more metal wires (220) in a spiral shape, in a multilayered manner, and in such a manner that portions of the metal wires adjacent in the inner and outer diameter directions extend in directions crossing each other. The filter is provided with a deformed joining portion (231) including a first metal wire portion (220A) that is pressed and deformed, and a second metal wire portion (220B) that is pressed and deformed via the first metal wire portion and joined to the first metal wire portion by resistance spot welding, the deformed joining portion entering a communication space located on the inner side thereof. Since the metal wire is pressed and deformed at the deformed joining portion, the deformed joining portion is less likely to be hooked to other members or the like when the filter is operated.

Description

Technical Field

[0001] This invention relates to a filter, a method for manufacturing the filter, and a gas generator. Background Technology

[0002] Airbags are devices installed in vehicles such as automobiles to protect occupants from the impact of collisions. A gas generator that causes the airbag to inflate and deploy instantly during a collision burns a propellant, instantly producing a large amount of gas that inflates and deploys the airbag. A metal filter is built into the gas generator to control and cool the high-temperature gas generated by the combustion of the propellant.

[0003] Patent Document 1 discloses a filter for a wound-wire gas generator, which is formed by winding a metal wire at a specified helix angle α. Patent Document 1 also describes that the metal wire is welded to the winding body.

[0004] Existing technical documents Patent documents Patent Document 1: Japanese Patent Publication No. 2009-533221 Summary of the Invention

[0005] The problem that the invention aims to solve Here, the welded parts formed on the outer side of the wound filter may get caught on other parts during filter handling, assembly, and other operations, which may damage the filter itself or other parts.

[0006] The present invention was made in view of the above circumstances, and its purpose is to make it less likely for the joined metal wire to snag on other components, etc.

[0007] Methods for solving problems To address the aforementioned issues, the present invention provides a hollow cylindrical filter, which is formed by winding one or more metal wires in a spiral or multi-layered manner with adjacent metal wire portions extending in mutually intersecting directions in the inner and outer diameter directions. The filter is characterized by having a deformable joint, comprising a first metal wire portion that is pressed and deformed, and a second metal wire portion that is pressed and deformed via the first metal wire portion and joined to the first metal wire portion by resistance spot welding. The deformable joint extends into a communicating space located inside it.

[0008] Invention Effects According to the present invention, the joined metal wire portion is less likely to snag on other components, etc. Attached Figure Description

[0009] Figure 1This is a schematic perspective view of a filter according to one embodiment of the present invention.

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

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

[0012] Figure 4 Images (a) to (c) are magnified three-dimensional views of the deformed joint.

[0013] Figure 5 The diagram shows a portion of the filter corresponding to the first embodiment of the present invention, presented as a photograph of the actual product.

[0014] Figure 6 (a) and (b) are schematic diagrams illustrating the function of the present invention.

[0015] Figure 7 This is a partial cross-sectional perspective view showing the metal wire used in the filter according to the second embodiment of the present invention.

[0016] Figure 8 The diagram shows a portion of the filter corresponding to the second embodiment of the present invention, presented as a photograph of the actual object.

[0017] Figure 9 (a) and (b) are schematic diagrams illustrating the method for determining the formation position of the second joint of the present invention. Detailed Implementation

[0018] The present invention will now be described in detail using illustrated embodiments. Unless otherwise specified, the constituent elements, types, combinations, shapes, and relative arrangements described in these embodiments are not intended to limit the scope of the invention, but are merely illustrative examples.

[0019] [Approximate shape of the filter] Figure 1 This is a schematic perspective view of a filter according to one embodiment of the present invention.

[0020] The hollow cylindrical filter (hereinafter referred to as the filter) 200 of the present invention is formed by winding at least one continuous metal wire 220 in a spiral and multi-layered manner with a certain pitch, with a certain inclination angle relative to the axial direction (vertical direction in the figure). Each layer formed by winding the metal wire 220 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 filter when viewed from the front. Furthermore, the metal wires constituting adjacent wire layers in the inner and outer diameter directions extend in mutually intersecting directions (not parallel).

[0021] Figure 1 The direction of extension of the metal wire portion 220(n) (thickness omitted in the figure) constituting the outermost wire layer Ln (the length direction of the metal wire portion 220(n)) is the direction shown by the solid arrow, and the direction of extension of the metal wire portion 220(n-1) constituting the inner adjacent wire layer Ln-1 (the length direction of the metal wire portion 220(n-1)) is the direction shown by the dashed arrow.

[0022] That is, the filter 200 has: a wire layer (e.g., wire layer L1) formed by spirally winding metal wires 220 at a certain angle relative to the axial direction; and other wire layers (e.g., wire layer L2) that overlap the outer periphery of a wire layer L1 and are formed by spirally winding metal wires at a different angle than the metal wires constituting the wire layer L1. The metal wires constituting a wire layer L1 and the adjacent wire layers L2 are configured to be non-parallel to the axial direction and intersect each other.

[0023] Alternatively, the metal wires constituting the wire layer may have varying tilt angles relative to the axial direction within the wire layer.

[0024] This filter 200 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, firstly, the filter is configured to form a flow path that allows the fluid to pass through in the direction overlapping the wire layers, i.e., radially. The fluid can pass 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, radially does not strictly refer to the diameter direction (radial direction), but rather means approximately radial relative to the axial and circumferential directions.

[0025] The size of the filter (inner diameter, outer diameter, axial dimensions, etc.) is appropriately determined based on the structure and size of the device assembling the filter.

[0026] The types of metals that can be used as materials for this filter include iron, mild steel, stainless steel, nickel alloys, copper alloys, etc., with austenitic stainless steel (SUS304) being the preferred choice.

[0027] Furthermore, the thickness and cross-sectional shape (the shape of the cross-section in the direction orthogonal to the length of the wire) of the filter are appropriately determined based on the size of the filter, the substances removed by the filter, pressure loss, and other factors. For example, the cross-sectional area of ​​the wire used in filters for gas generators is 0.03~0.8 mm². 2 (If a circle with a cross-sectional shape of a perfect circle is used as a reference, the wire diameter is approximately 0.2~1mm).

[0028] The filter uses metal wire formed by rolling bare metal wire with a circular cross-section into a specified shape. The metal wire used is either flat wire rolled into a flat rectangular cross-section or irregularly shaped wire rolled into a roughly V-shaped cross-section. In the filter 200, the metal wire 220 is wound in a non-twisting manner.

[0029] [Filter manufacturing method] Figure 2 This is a schematic diagram illustrating the manufacturing method of the filter.

[0030] To manufacture the filter 200, firstly, one end (starting end, winding start end) of the metal wire 220 is secured at a suitable position on the mandrel 131 constituting the winding device 130. While applying a predetermined tension to the metal wire 220, the mandrel 131 is rotated at a predetermined speed in a certain direction around its 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.

[0031] For example, in the first metal wire layer directly wound around the outer periphery of the mandrel 131, when each metal wire 220 is tilted at a predetermined angle θ in the clockwise direction relative to the axial direction of the mandrel 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 mandrel 131.

[0032] When the starting end of the metal wire 220, which is held on one axial end of the mandrel 131 (right side in the figure), has been wound two or more layers on the mandrel 131, it is folded back towards the other axial end of the mandrel 131 (left side in the figure). By further winding the metal wire 220 over the folded-back starting end, the starting end is clamped and fixed between adjacent wire layers. Then, after winding the metal wire 220 a predetermined number of turns (predetermined number of layers), the other end (terminal portion, winding terminal side) of the metal wire 220 is joined and fixed at an appropriate position on the wound metal wire 220 by resistance spot welding. The welding machine 150 for resistance spot welding the metal wire 220 is equipped with an electrode 151 through which the current required for joining flows. The electrode 151 is configured to be able to move forward and backward relative to the mandrel 131, to press the metal wire 220 with a predetermined pressure, and to allow the joining current to flow while it is pressed.

[0033] After joining the ends of the metal wire 220, the metal wire 220 is cut off and removed from the mandrel 131 by an appropriate method, thereby obtaining a hollow cylindrical body.

[0034] The angle (winding angle) of the metal wire 220 relative to the axial direction of the mandrel 131, and the spacing (pitch) between adjacent metal wires 220 in 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 turns, the pressure loss of the fluid passing through the filter can be controlled to an appropriate value.

[0035] In addition, the mandrel 131 is roughly cylindrical or cylindrical and is generally made of metals such as stainless steel, copper alloy, and aluminum alloy. The inner diameter of the filter 200 is approximately the same as the outer diameter of the mandrel 131, and the outer diameter of the filter 200 is adjusted appropriately according to the thickness and number of turns of the metal wire 220.

[0036] Hollow cylindrical bodies manufactured using the above methods can be used directly as filters without the need for overall sintering.

[0037] [Gas generator equipped with filters] Figure 3 This is a schematic diagram of a disc-shaped gas generator assembled with a filter according to one embodiment of the present invention.

[0038] The disc-shaped gas generator 1 has a generally cylindrical housing that is closed at both axial end faces (upper and lower ends in the figure). Within the housing's internal storage space are housed internal components such as a retainer 30, an igniter 40, a cup-shaped component 50, a propellant 59, a gas generating agent 61, a lower support component 70, an upper support component 80, a buffer 85, and a filter 200. Furthermore, a combustion chamber 60, primarily housing the gas generating agent 61 from the aforementioned internal components, is disposed within the housing's internal storage space.

[0039] The shell has a lower side shell 10 with an opening at the top (having an opening on the upper surface) and a generally bottom-cylindrical shape, and an upper side shell 20 with an opening at the bottom (having an opening on the lower surface). 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.

[0040] With the upper surface opening facing the lower surface opening, the upper end of the lower side shell 10 is pressed into the lower end of the upper side shell 20, and the abutting part of the two or its vicinity is joined by electron beam welding, laser welding or friction pressing, thereby integrating the two into one unit.

[0041] The upper side shell 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 used to fix the disc-shaped gas generator 1 to an external component (such as a retainer provided on the airbag device).

[0042] A protruding cylindrical portion 13 protrudes from the center of the bottom plate portion 11 of the lower side shell 10 toward the top plate portion 21 of the upper side shell 20. As a result, a recessed portion 14 is formed on the outer side of the shell, that is, on the side opposite to the protruding cylindrical portion 13. An opening portion 15 is formed on the end face of the top plate portion 21 side of the protruding cylindrical portion 13 to communicate between the inside and outside of the shell.

[0043] On the side of the protruding cylindrical portion 13 and the side of the recessed portion 14, a retaining portion 30 for fixing the igniter 40 is provided via the opening 15. The retaining portion 30 is made of insulating resin and is formed by insert molding.

[0044] The igniter 40 is a flame-generating unit, comprising: an ignition part 41 including an ignition powder and a resistor that ignites the ignition powder; and a pair of terminal pins 42 that supply power to the resistor. The resistor generates Joule heat, igniting the ignition powder. A female connector part 34, communicating with the terminal pins 42, is disposed within the recess 14. The female connector part 34 is fixed by a retaining part 30 while ensuring airtightness within the storage space.

[0045] A cup-shaped component 50 is assembled on the base plate 11 in such a way that it covers the protruding cylindrical portion 13, the retaining portion 30, and the igniter 40. The ignition propellant 59 is housed in the hollow portion of the cup-shaped component 50.

[0046] When the igniter 40 is activated and the propellant 59 is ignited, the cup-shaped component 50 may rupture, deform, or melt due to the increased pressure and heat generated within its internal space. The space within the housing that partially encloses the cup-shaped component 50 is a combustion chamber 60 containing the gas generator 61. The gas generator 61 is disposed adjacent to the outer surface of the cup-shaped component 50.

[0047] Within the space that radially surrounds the combustion chamber 60 containing the gas generator 61, a filter 200 according to an embodiment of the present invention is arranged along the inner circumference of the housing. The filter 200 has a cylindrical shape and is arranged such that its central axis Ax1 is substantially aligned with the axial direction of the housing.

[0048] When the gas generated in the combustion chamber 60 passes through the filter 200, it functions as a cooling unit that cools the gas by absorbing the high-temperature heat it contains, and also as a removal unit that removes residues (slag) and the like contained in the gas. Furthermore, the filter 200 is arranged apart from the peripheral walls 12 and 22, forming a gap 28 of a predetermined size between the peripheral wall 12 of the lower side shell 10 and the peripheral wall 22 of the upper side shell 20, which constitute the peripheral wall of the housing.

[0049] A plurality of gas outlets 23 are provided on the peripheral wall 22 of the upper side shell 20 facing the filter 200. These gas outlets 23 are used to discharge the gas that has passed through the filter 200 to the outside of the shell. Furthermore, sealing strips 24 are affixed to the gas outlets 23. The sealing strips 24 ensure the airtightness of the combustion chamber 60.

[0050] A circular lower support member 70 is disposed on the bottom plate portion 11 side inside the combustion chamber 60. This lower support member 70 fixes the filter 200 to the housing and prevents 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. Additionally, a disc-shaped upper support member 80 is disposed on the top plate portion 21 side inside the combustion chamber 60. This upper support member 80 fixes the filter 200 to the housing and prevents 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.

[0051] A disc-shaped buffer 85 is disposed between the upper support member 80 and the gas generator 61, pressing the gas generator 61 toward the base plate 11. The buffer 85 is made of asbestos, foamed resin, etc., to prevent the gas generator 61 from being crushed due to vibration or other reasons.

[0052] The gas generator 1 operates as follows: First, upon vehicle collision, the igniter 40 is activated by power from the control unit. With the activation of the igniter 40, the propellant 59 begins to burn. 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 strip 24 that closes the gas outlet 23 ruptures, and the gas is ejected through the gas outlet 23 to the outside of the housing. The ejected gas inflates and deploys the airbag.

[0053] [First Implementation] like Figure 1 As shown, in the filter 200 of the embodiment of the present invention, the metal wire 220 has a joint portion 230 at a suitable position in its length direction, which is resistively spot welded to the filter 200 at a suitable position. At least one of the joint portions 230 is a deformable joint portion 231 that is pressed and deformed. The deformable joint portion 231 is bent and deformed into a concave shape by being pressed with a force exceeding the sufficient pressure required to join the metal wire 220. The deformable joint portion 231 is preferably formed at the end (terminal portion) on the winding terminal side of the metal wire 220.

[0054] <Jointing area> The filter 200 has multiple contact portions where metal wire parts come into contact with each other. The portions other than the joint portion 230 are non-joined portions. For the filter 200, no heat treatment (e.g., heat treatment for sintering) is performed to join all (or multiple) of the contact portions together. Therefore, the manufacturing cost of the filter 200 can be reduced, and the manufacturing time of the filter 200 can be shortened.

[0055] <Deformation shape of the deformable joint> Figure 4 Images (a) to (c) are magnified three-dimensional views of the deformed joint.

[0056] For ease of explanation, this figure shows an example of a deformable joint formed by the terminal portion of a metal wire and a portion of the metal wire located on the inner diameter side of the terminal portion. However, the positional relationship between the two portions of the metal wire forming the deformable joint is not limited to this. Furthermore, the deformable joint may also be formed by three or more portions of metal wire. The various shape examples shown below can be combined with each other as long as they do not contradict each other.

[0057] The deformable joint 231 shown in the figure is formed at the end portion 221 of the metal wire 220. The portion of the metal wire forming the deformable joint 231 is deformed from its shape during winding (a spiral shape along the circumference) in a locally recessed manner.

[0058] The deformable joint 231 is configured to include from Figure 2 The electrode 151 shown (pressing unit or pressure unit) is directly deformed by the pressing force (pressure) on the first metal wire portion (first part) 220A, and the second metal wire portion (second part) 220B is joined to the first metal wire portion 220A.

[0059] Figure 4 The metal wire 220 shown is a so-called flat wire rolled into a flat rectangular cross-sectional shape. The metal wire 220 is wound without twisting within the filter 200. That is, it is wound in such a way that one side of the metal wire 220 in the thickness t1 direction always faces the inner diameter side (or the outer diameter side), and the opposite side of the metal wire 220 in the thickness t1 direction always faces the outer diameter side (or the inner diameter side).

[0060] <<Shape example 1>> like Figure 4 As shown in (a), at the deformable joint 231, both the first metal wire portion 220A and the second metal wire portion 220B are pressed and deformed (bent) in the inward direction. The second metal wire portion 220B is pressed and deformed via the first metal wire portion 220A. The first metal wire portion 220A and the second metal wire portion 220B shown in the figure are metal wires belonging to different wire layers and extending in the intersecting direction. The wire layer to which the first metal wire portion 220A belongs and the wire layer to which the second metal wire portion 220B belongs may be radially adjacent or radially non-adjacent.

[0061] A mesh-like communicating space 203 is formed in the filter 200 to allow the filtered fluid to pass radially. The deformable joint 231 enters the communicating space 203 located on its inner side. On the side where the first and second metal wire portions 220A and 220B are deformed (inner diameter side in the figure), there is a communicating space 203 capable of accommodating the deformed first and second metal wire portions 220A and 220B (i.e., the entire deformable joint 231). Within the communicating space 203 into which the deformable joint 231 enters, there are no other portions of the metal wire 220, i.e., portions that hinder the deformation of the first and second metal wire portions 220A and 220B. In other words, it is controlled such that the metal wire portions in the following positional relationship are selected as the first and second metal wire portions 220A and 220B forming the deformable joint 231, i.e., there is a positional relationship on the side where the metal wire is pressed and deformed that allows the communicating space 203 to accommodate the deformable joint 231.

[0062] By selecting the first and second metal wire portions 220A and 220B in such a positional relationship, the deformable joint 231 can be formed with the minimum required pressure. Furthermore, the deformable joint 231 is less susceptible to tension from other metal wire portions that do not constitute it, thus improving the shape retention of the deformable joint 231.

[0063] The first and second metal wire portions 220A and 220B are deformed in a manner that allows them to enter a different wire layer than the wire layer to which each metal wire portion belongs. That is, the first and second metal wire portions 220A and 220B are pressed inwards at a position closer to the inner diameter than their radial positions at the time of winding. Preferably, the amount of pressing deformation of the first metal wire portion 220A, or the first and second metal wire portions 220A and 220B, is such that, relative to their undeformed shape, at least the thickness t1 of the deformed metal wire 220 is pressed in.

[0064] <<Shape example 2>> like Figure 4 As shown in (b), the deformable joint 231 can also be made of only one component. Figure 2 The electrode 151 is shown directly pressing the first metal wire portion 220A to deform it. In this case, the second metal wire portion 220B remains in the wire layer to which the second metal wire portion 220B belongs, and is engaged with the first metal wire portion 220A without detaching from that wire layer. Such a deformed joint 231 is formed at least by metal wire portions belonging to wire layers that are not adjacent to each other. Figure 4 (b) shows a deformable joint 231 formed by a portion of metal wire extending in the intersecting direction.

[0065] The first metal wire portion 220A is deformed by entering a different wire layer than the wire layer to which it belongs. Preferably, the amount of pressing deformation of the first metal wire portion 220A is such that, relative to its undeformed shape, it is pressed into at least the thickness t1 of the deformed metal wire 220.

[0066] <<Shape example 3>> like Figure 4 As shown in (c), the deformable joint 231 can also be formed by joining a first metal wire portion 220A and a second metal wire portion 220B extending in the same direction. Such a deformable joint 231 is formed at least by metal wire portions belonging to wire layers that are not adjacent to each other.

[0067] The deformable joint 231 shown in the figure is deformed only in the first metal wire portion 220A, but it can also be deformed in the second metal wire portion 220B.

[0068] <Location of Deformation Joint> The deformable joint 231 is formed at an appropriate position on the outer surface of the filter 200. Specifically, the deformable joint 231 is formed on... Figure 1 The appropriate position of any one of the outer peripheral surface (radially outer side, outermost peripheral part), inner peripheral surface (radially inner side, innermost peripheral part), and axial end face of the filter 200 shown.

[0069] In particular, the deformable joint 231 is preferably formed on the outermost Ln layer constituting the filter 200. Figure 1 The appropriate location of the metal wire portion of the (). Specifically, such as Figure 4 As shown, the deformable joint 231 is preferably formed at the terminal portion 221.

[0070] <Methods for forming deformable joints> The deformable joint 231 is formed by pressing and deforming the first metal wire portion 220A and then joining the first metal wire portion 220A with the second metal wire portion 220B. When the deformable joint 231 is formed on the terminal portion 221 of the metal wire 220, after joining the terminal portion 221 (the first metal wire portion 220A) to the second metal wire portion 220B located on its inner diameter side, the metal wire 220 is cut by an appropriate method.

[0071] <Modified Implementation> The filter 200 may also have a unique joint 230, which is a deformed joint 231 formed on the end portion 221 of the metal wire 220.

[0072] The filter 200 may also have multiple joints 230. In this case, at least one of the joints 230 is a deformable joint 231. When the filter 200 has multiple joints 230, the deformable joint 231 is preferably formed at least at the end portion 221 of the metal wire 220.

[0073] The joint 230 (non-deformable joint) that does not constitute the deformable joint 231 is subjected to sufficient pressure required to join the metal wires 220 and is welded. Each joint 230 is joined individually.

[0074] <First Embodiment> Figure 5This is a photograph showing a portion of the filter corresponding to the first embodiment of the present invention. The figure shows an example where the terminal portion 221 of the metal wire 220 is a deformable joint 231 formed by resistance spot welding.

[0075] The terminal portion 221 of the first metal wire portion 220A is resistance-spot welded to the second metal wire portion 220B, which is located on its inner diameter side and intersects with the first metal wire portion 220A. The terminal portion 221 is subjected to resistance welding from electrode 151. Figure 2 The second metal wire portion 220B is also deformed in the inward direction by the pressure from the terminal portion 221. Because the terminal portion 221 is deformed by the pressure, the possibility of the cut end 221a of the metal wire 220 getting caught on other components or being damaged during operations such as handling and assembling the filter 200 is reduced.

[0076] <Function> Figure 6 These are schematic diagrams illustrating the operation of the present invention, wherein (a) shows an example in which the terminal portion 221 of the metal wire 220 is used as a deformable joint portion 231, and (b) shows a comparative example in which the terminal portion 221 of the metal wire 220 is used as a non-deformable joint portion 232. Furthermore, the direction perpendicular to the plane of the paper in the figures corresponds to the axial direction of the filter.

[0077] like Figure 6 As shown in (b), at the non-deformable joint 232 that has not been pressed and deformed in the inward direction, when the cut end 221a protrudes from the second metal wire 220B, the cut end 221a may get caught on other parts or damage other parts.

[0078] On the other hand, such as Figure 6 As shown in (a), the deformable joint 231 of the embodiment of the present invention is pressed and deformed in the inward direction. Therefore, even if the cut end 221a protrudes from the second metal wire 220B, the possibility of the cut end 221a getting hooked on other parts or damaging other parts is reduced.

[0079] <Effect> In this embodiment, the deformable joint is pressed and deformed in the inward direction, so that it is less likely to snag on other components during filter operation. Therefore, the deformable joint is less likely to peel off. In particular, when the end portion of the metal wire is used as the deformable joint, it is possible to prevent the end portion from snag on other components and peeling off. Furthermore, the operability of the filter is improved.

[0080] [Second Implementation] The second embodiment of the present invention is characterized in that the metal wire forming the filter is an irregularly shaped wire having a generally V-shaped cross-sectional shape.

[0081] Such metal wire is obtained by rolling bare metal wire with a circular cross-section using rolling rolls with a specified surface shape corresponding to the profiled wire.

[0082] The parts other than the structure determined by the shape of the metal wire are the same as in the first embodiment. Hereinafter, the parts that differ from the first embodiment will be described.

[0083] <Wire Shape> Figure 7 This is a partial cross-sectional perspective view showing the metal wire used in the filter according to the second embodiment of the present invention.

[0084] The metal wire 220 has a generally V-shaped shape when viewed in cross-section. The metal wire 220 has a protrusion 241 extending along its entire length in the length direction on one side in the thickness direction, and a recess 242 extending along its entire length in the length direction on the other side (opposite side, back side) in the thickness direction. A recess 242 is formed on the back side of the protrusion 241, which is formed in a curved shape protruding to one side, and is recessed in a shape symmetrical to the protrusion 241. The metal wire 220 is bent with a generally constant wall thickness t2 when viewed in cross-section.

[0085] The metal wire 220 is wound without twisting within the filter 200. That is, it is wound in such a way that the protrusion 241 formed on one side of the thickness direction of the metal wire 220 always faces the inner diameter side (or the outer diameter side), and the concave portion 242 formed on the opposite side of the thickness direction of the metal wire 220 always faces the outer diameter side (or the inner diameter side).

[0086] <Wire shape at the joint> In this embodiment, also based on Figure 4 As described in the first embodiment, the metal wire portion forming the deformable joint 231 is deformed from its wound shape (a spiral shape along the outer circumferential surface) in a partially recessed manner.

[0087] Welding current is supplied to the first and second metal wire portions 220A and 220B while they are pressed in a bent manner toward the second metal wire portion 220B. Therefore, the first metal wire portion 220A and the second metal wire portion 220B together deform in such a way that the height of the protrusion 241 decreases (or the depth of the recess 242 becomes shallower). In this case, the first metal wire portion 220A and the second metal wire portion 220B may also be deformed into a flat shape. Alternatively, the first metal wire portion 220A may be deformed according to the shape of the second metal wire portion 220B.

[0088] <Second Embodiment> Figure 8 The diagram shows a portion of the filter corresponding to the second embodiment of the present invention, presented as a photograph of the actual object.

[0089] The terminal portion 221 of the first metal wire portion 220A is resistance-spot welded to the second metal wire portion 220B, which is located on its inner diameter side and intersects with the first metal wire portion 220A. The terminal portion 221 is pressed and deformed in the inner diameter direction, and the second metal wire portion 220B is also pressed and deformed in the inner diameter direction by the pressing force from the terminal portion 221.

[0090] The terminal portion 221, when pressed in the inward direction, has its protrusion 241 and recess 242 ( Figure 7 The first metal wire portion 220A is joined to the second metal wire portion 220B in a deformed state where its height decreases. Alternatively, the terminal portion 221 is joined to the second metal wire portion 220B in a state where it is deformed to match the shape of the second metal wire portion 220B by pressing in the inward direction. The increased joining area between the first metal wire portion 220A and the second metal wire portion 220B at the terminal portion 221 improves the joining strength at the deformable joint portion 231.

[0091] <Effect> This embodiment achieves the same effect as the first embodiment. Furthermore, by making the metal wire a shaped wire, the joint area between the first and second metal wire portions at the deformable joint can be increased, thereby improving the joint strength.

[0092] [Third Implementation Method] Figure 9 (a) and (b) are schematic diagrams illustrating the method for determining the formation position of the second joint of the present invention. Figure 9 This is equivalent to removing the portion of the metal wire 220 located between the two joints 230, 230 from the filter and viewing it from one side of the axial direction.

[0093] The filter of this embodiment is characterized by having two joints 230, 230 formed by resistance spot welding of metal wires 220 together. One joint 230 is a deformable joint 231 formed at the terminal portion 221, and the other joint 230 is a second joint 233 formed at other parts of the outermost wire layer Ln. The second joint 233 is formed by a third metal wire portion (third part) 220C belonging to the outermost layer Ln together with the first metal wire portion 220A, and a fourth metal wire portion (fourth part) 220D located on the inner diameter side of the third metal wire portion 220C. The second joint 233 may or may not be a deformable joint.

[0094] Assembled in gas generator 1 ( Figure 3 In the filter, when gas is generated, an external force is applied from the hollow part to expand the filter diameter outward.

[0095] like Figure 9 As shown in (a), the reaction force P / 2 is decomposed into a radial component and a circumferential component.

[0096] When θ≠180deg, for P / 2, there is a residual radial force component. This means that a force is generated that causes the joints 230, 230 to peel off radially.

[0097] like Figure 9 As shown in (b), when θ = 180°, the radial reaction force is zero, and the circumferential reaction force is maximum (= P / 2). That is, when θ = 180°, no stress is generated that would cause the metal wire portions 220A and 220C forming the joints 230 and 230 to peel off in the outer diameter direction, and the positional relationship of the joints 230 and 230 is optimal.

[0098] Furthermore, when θ=180deg, it is also preferable from the viewpoint of preventing current shunting during resistance spot welding.

[0099] <Effect> When welding thinly rolled metal wires together, it is difficult to ensure sufficient weld penetration along the thickness of the wires. Consequently, the welded portion of the filter tends to have lower resistance to radial peeling forces.

[0100] When the joint provided in the outermost metal wire is only the terminal part, the terminal part shall bear at least the entire load of the outermost wire.

[0101] As in this embodiment, when the joint portion formed in the outermost metal wire is located at the terminal portion and the other two portions, the terminal portion only bears the load on the metal wire between the joint portions, thus reducing the load borne by the terminal portion. This reduces the risk of the filter detaching due to the joint portion peeling off.

[0102] [Summary of embodiments, functions, and effects of the present invention] <First Implementation Method> The hollow cylindrical filter 200 of this method is formed by winding one or more metal wires 220 in a spiral or multi-layered manner, with adjacent metal wire portions extending in mutually intersecting directions in the inner and outer diameter directions. The filter is characterized by having a deformable joint 231, which includes a first metal wire portion 220A that is pressed and deformed, and a second metal wire portion 220B that is pressed and deformed via the first metal wire portion and joined to the first metal wire portion by resistance spot welding. The deformable joint extends into a communicating space located inside it.

[0103] According to this method, the pressed and deformed part is less likely to get caught on other parts, etc.

[0104] <Second Implementation Method> The hollow cylindrical filter 200 of this method is formed by winding one or more metal wires 220 in a spiral or multi-layered manner, with adjacent metal wire portions extending in mutually intersecting directions in the inner and outer diameter directions. The filter is characterized by having a deformable joint 231, which includes a first metal wire portion 220A that is pressed and deformed, and a second metal wire portion 220B that is joined to the first metal wire portion by resistance spot welding. The first metal wire portion enters a different wire layer than the wire layer to which it belongs and joins with the second metal wire portion, and the second metal wire portion does not detach from its own wire layer.

[0105] According to this method, the pressed and deformed part is less likely to get caught on other parts, etc.

[0106] <Third Implementation Method> The filter 200 of this method is characterized in that: a deformable joint 231 is formed at the end (terminal portion 221) of the winding terminal side of the metal wire 220.

[0107] According to this method, the terminal part is not easily hooked onto other components, and it is not easily detached.

[0108] <Fourth Implementation Method> The filter 200 of this method is characterized in that: the filter 200 has a second joint 233, which is formed by resistance spot welding of a third metal wire portion 220C located on the outermost layer Ln and a fourth metal wire portion 220D located on the inner diameter side of the third metal wire portion. The deformable joint 231 and the second joint are formed in the following positional relationship: when an external force is applied from the hollow portion to expand the filter in the outer diameter direction, no stress is generated that causes the first metal wire portion 220A and the third metal wire portion to peel off in the outer diameter direction.

[0109] According to this method, the terminal section 221 only bears the load on the metal wires between the joints, thus reducing the load borne by the terminal section. This reduces the risk of the filter coming apart due to the joints peeling off.

[0110] <Fifth Implementation Method> The filter 200 of this method is characterized in that: the first metal wire portion 220A constituting the deformable joint 231 is pressed and deformed by at least a thickness t1 of the first metal wire portion.

[0111] According to this method, the deformable joint is pressed with a force exceeding the sufficient pressure required to join the metal wires, thereby being reliably pressed into the inner side, so that the pressed deformable part is less likely to hook onto other parts, etc.

[0112] <Sixth Implementation Method> The gas generator 1 of this method is characterized by being equipped with the filter 200 described in each embodiment.

[0113] The gas generator of this method enjoys the effects described in each embodiment.

[0114] <Seventh Implementation Method> The method for manufacturing the filter 200 of this type is characterized by comprising: a wire winding process in which one or more metal wires 220 are wound in a spiral or multi-layered manner such that adjacent metal wire portions in the inner and outer diameter directions extend in mutually intersecting directions; and a joining process in which a first portion (first metal wire portion 220A) of the metal wire is pressed and deformed, and the first portion is joined to a second portion (second metal wire portion 220B) of the metal wire by resistance spot welding, wherein in the joining process, the second portion is pressed and deformed via the first portion, and the first and second portions are brought into a communicating space located inside them.

[0115] The filter manufactured by this method enjoys the same effect as the first embodiment.

[0116] <Eighth Implementation Method> The method for manufacturing the filter 200 of this type is characterized by comprising: a wire winding process in which one or more metal wires 220 are wound in a spiral or multi-layered manner such that adjacent metal wire portions in the inner and outer diameter directions extend in mutually intersecting directions; and a joining process in which a first portion (first metal wire portion 220A) of the metal wire is pressed and deformed, and the first portion is joined to a second portion (second metal wire portion 220B) of the metal wire by resistance spot welding, wherein in the joining process, the second portion is not detached from the wire layer to which the second portion belongs, and the first portion is joined to the second portion while entering a wire layer different from the wire layer to which the first portion belongs.

[0117] The filter manufactured by this method enjoys the same effect as the second embodiment.

[0118] Symbol Explanation 1: (Disc-shaped) 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 strip; 25: Flange; 28: Gap; 30: Holding part; 34: Female connector; 40: Igniter; 41: Ignition part; 42: Terminal pin; 50: Cup-shaped component; 59: Propellant; 60: Combustion chamber; 61: Gas generating agent; 70: Lower support component; 80: Upper support component; 85: Buffer component; 130: Winding device; 131: Mandrel; 132: Guide component; 150: Welding machine; 151: Electrode (pressing unit); 200: Filter; 203: Connecting space; 220: Metal wire; 220(n), 220(n-1): Metal wire section; 220A: First metal wire section (first part); 220B: Second metal wire section (second part); 220C: Third metal wire section (third part); 220D: Fourth metal wire section (fourth part); 221: Terminal section; 221a: Cut end; 230: Joint; 231: Deformed joint; 232: Non-deformed joint; 233: Second joint; 241: Protrusion; 242: Recess; L1, L2...Ln: Wire layer; Ax1: (Filter) Central axis; Ax2: (Mandrel) Central axis; t1: (Overall thickness of metal wire); t2: (Shaped wire) Wall thickness.

Claims

1. A hollow cylindrical filter, It is composed of one or more metal wires wound in a spiral or multi-layered manner, with adjacent metal wire portions extending in mutually intersecting directions in the inner and outer diameter directions, characterized in that: The filter has a deformable joint, which includes a first metal wire portion that is pressed and deformed, and a second metal wire portion that is pressed and deformed via the first metal wire portion and joined to the first metal wire portion by resistance spot welding, the deformable joint extending into a communicating space located inside it.

2. The filter according to claim 1, characterized in that: The deformable joint is formed at the end of the winding terminal side of the metal wire.

3. The filter according to claim 1 or 2, characterized in that: The first metal wire portion constituting the deformable joint is pressed and deformed by at least a thickness t1 of the first metal wire portion.

4. A hollow cylindrical filter, It is composed of one or more metal wires wound in a spiral or multi-layered manner, with adjacent metal wire portions extending in mutually intersecting directions in the inner and outer diameter directions, characterized in that: The filter includes a deformable joint, which comprises a first metal wire portion that is pressed and deformed, and a second metal wire portion that is joined to the first metal wire portion by resistance spot welding. The first metal wire portion enters another wire layer that is different from the wire layer to which the first metal wire portion belongs and joins with the second metal wire portion, the second metal wire portion not detaching from the wire layer to which it belongs.

5. The filter according to claim 4, characterized in that: The deformable joint is formed at the end of the winding terminal side of the metal wire.

6. The filter according to claim 5, characterized in that: The filter has a second joint, which is formed by resistance spot welding of a third metal wire portion located on the outermost layer and a fourth metal wire portion located on the inner diameter side of the third metal wire portion. The deformable joint and the second joint are formed in such a positional relationship that when an external force is applied from within the hollow portion to expand the filter in the outward direction, no stress is generated that would cause the first metal wire portion and the third metal wire portion to peel off in the outward direction.

7. The filter according to any one of claims 4 to 6, characterized in that: The first metal wire portion constituting the deformable joint is pressed and deformed by at least a thickness t1 of the first metal wire portion.

8. A gas generator, characterized in that: The filter is assembled with any one of claims 1 to 7.

9. A method for manufacturing a filter, characterized in that, include: The wire winding process involves winding one or more metal wires in a spiral or multi-layered manner, with adjacent portions of the metal wires extending in mutually intersecting directions in the inner and outer diameter directions; and In the joining process, a first portion of the metal wire is pressed and deformed, and then the first portion is joined to a second portion of the metal wire by resistance spot welding. In the joining process, the second part is pressed and deformed via the first part, and the first and second parts are brought into the communicating space located inside them.

10. A method for manufacturing a filter, characterized in that, include: The wire winding process involves winding one or more metal wires in a spiral or multi-layered manner, with adjacent portions of the metal wires extending in mutually intersecting directions in the inner and outer diameter directions; and In the joining process, a first portion of the metal wire is pressed and deformed, and then the first portion is joined to a second portion of the metal wire by resistance spot welding. In the bonding process, the second part is prevented from detaching from the wire layer to which it belongs, and the first part is bonded to the second part while entering a different wire layer than the wire layer to which the first part belongs.

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