Zigzag path filter for airbag inflator

Abstract

The invention discloses a tortuous path filter for an airbag inflator. The airbag assembly may include an airbag and an inflator that provides inflation gas to inflate the airbag. A filter module may be positioned such that inflation gas exiting the inflator must first pass through the filter module. The filtration module may be formed from a sheet metal wrapped in a generally helical tubular shape. The filtration module may have an inner layer, an intermediate layer, and an outer layer. The intermediate layer generally surrounds the inner layer, and the outer layer generally surrounds the inner layer and the intermediate layer in a helical fashion. The inner layer, the intermediate layer, and the outer layer may each have a pattern of holes and dimples that are separated and / or displaced from each other. The dimples may protrude toward adjacent layers to maintain a pitch such that a relatively unrestricted air flow can flow from the apertures of the inner layer through misaligned apertures of the intermediate layer and the outer layer. The resulting tortuous gas flow path may assist in slowing, cooling, and / or purifying the gas before it exits the inflator.

Description

[0001] This application is a continuation-in-part of the patent application having application number 201780046675.1, PCT international application number PCT / US2017 / 047782, and having the title "Meandering Path Filter for Airbag Inflator" and having a filing date of August 21, 2017. TECHNICAL FIELD

[0002] The present invention relates to automotive safety. More specifically, the present invention relates to cost-effective airbag inflators that enhance airbag systems. BACKGROUND

[0003] Inflatable safety restraint devices, or airbags, are mandatory for most new vehicles. Airbags are typically installed as part of a system, with airbag modules in the steering wheel on the driver's side of the car and in the instrument panel on the passenger's side of the car. In the event of an accident, sensors within the vehicle measure an abnormal deceleration and trigger the ignition of a charge contained within an inflator. Expanding gases from the charge fill the airbag, which immediately inflates in front of the driver and passenger to protect them from harmful impacts within the car. Typically, the airbags are hidden in the vehicle's interior trim and are not visible during normal vehicle operation. In addition to driver's side and passenger's side airbags, many vehicles also have other airbags, such as side airbags and / or inflatable curtain airbags that inflate on the outside of the vehicle occupants to provide side impact protection, roll-over protection, ejection protection, and / or small overlap collision protection, knee airbags, inflatable seat belts, etc.

[0004] Inflators are a critical part of the airbag assembly because they provide the inflation gas needed to inflate the airbag cushion. Typically, inflators are compressed gas inflators, pyrotechnic inflators, or hybrid inflators. "Compressed gas" inflators contain pressurized gas, while "pyrotechnic" inflators contain a pyrotechnic gas generant that ignites to produce gas. "Hybrid" inflators typically use both compressed gas and pyrotechnic charges. Some inflators are "dual stage," meaning they can receive two separate activation signals to enable the production of a selectively variable amount of inflation gas, while others have only a single stage. However, single stage inflators can have multiple timing events, such as igniting multiple individual pyrotechnic charges and / or releasing different volumes of compressed gas, all triggered by a single activation signal.

[0005] All types of inflators are typically made from a wide variety of components. Each inflator can contain a series of chambers, diffusers, filters, frangible membranes, initiators, generants, baffles, and containers, attachment hardware, and other components. Each of these components significantly adds to the cost of the inflator. Thus, inflators typically make up a large portion of the cost of the airbag assembly.

[0006] Additionally, a series of different manufacturing steps can be required to manufacture each inflator. The number of steps involved not only further increases the cost of the potential inflator, but also increases the likelihood of material or process defects in the finished inflator. SUMMARY

[0007] The various systems and methods of the present disclosure have been developed in response to the present state of the art, and in particular, in response to the problems and needs in the art that have not yet been fully resolved by currently available airbag systems and methods. Accordingly, it is advantageous to provide airbag systems and methods that provide reliable protection for vehicle occupants in a variety of crash situations. Additionally, it is advantageous to minimize manufacturing and installation costs. Exemplary embodiments of the present disclosure can have other benefits not specifically described herein.

[0008] To achieve the foregoing, the exemplary embodiments broadly described herein include an inflator that can be part of an airbag assembly for protecting a vehicle occupant from injury. The inflator can include a housing having a central longitudinal axis and can have one or more diffuser holes through which inflation gas is expelled to fill an airbag. The inflator generally has a gas source contained within a chamber defined within the housing. The gas source can be compressed gas, pyrotechnic gas generant, or a combination of compressed gas and generant. The gas source provides gas in response to receiving an activation signal.

[0009] In some embodiments, the inflator will have a filter or filter module designed to slow the flow of gas, cool the gas before entering the airbag, and trap impurities in the gas. In the present disclosure, exemplary embodiments have a filter module that includes a single body (which can be made of metal such as steel) having an inner portion, a middle portion, and an outer portion that is prepared and then formed into a generally tubular shape by wrapping around a mandrel of the correct size or by other means. The filter module is then positioned within the housing to surround the central longitudinal axis. When wrapped and positioned within the housing of the inflator, the filter module defines the inner, middle, and outer layers and maintains its shape without the need for welding.

[0010] The inner layer includes a first array of holes that, in some embodiments, are formed by perforations. Inflation gas is received inside the inner layer and passes through the first array of holes to the middle layer. The middle layer includes a second array of holes that can be formed by perforations. Each hole in the second array of holes is not radially aligned with a hole in the first array of holes that is closest to such hole in the second array of holes. This causes the inflation gas passing through the inner layer to change direction and flow axially to find an exit.

[0011] The intermediate layer is positioned such that the insufflation gas passes through the second array of holes to reach the outer layer. The outer layer includes a third array of holes. Again, each hole in the second array of holes is not radially aligned with a hole in the third array of holes that is closest to such hole in the second array of holes. This time, the insufflation gas that passed through the intermediate layer is again forced to change direction and flow axially to find an exit. Each hole in the third array of holes is not aligned with any of the one or more diffuser holes. Before the insufflation gas can exit the insufflator through any of the diffuser holes, the insufflation gas must again change direction and travel axially to find a diffuser hole through which to exit.

[0012] Of course, it should be understood that there can be more than one intermediate layer, and that the intermediate layers do not necessarily need to have the same array of holes.

[0013] Exemplary embodiments of the present disclosure have a filtration module having a single body with a plurality of protrusions. At least one of the plurality of protrusions is disposed adjacent to at least one of the holes of the first array of holes of the inner layer, and some embodiments can have one protrusion disposed adjacent to each of the holes of the first array of holes of the inner layer. At least one other of the plurality of protrusions is disposed adjacent to at least one of the holes of the second array of holes of the intermediate layer. At least one other of the plurality of protrusions is disposed adjacent to at least one of the holes of the third array of holes of the outer layer. In some embodiments, each protrusion of the inner layer protrudes toward the intermediate layer, each protrusion of the intermediate layer protrudes toward the outer layer, and each protrusion of the outer layer protrudes toward the inner wall of the housing. The protrusions are sized and shaped to maintain a gap between the inner layer and the intermediate layer, between the intermediate layer and the outer layer, and between the outer layer and the inner wall of the housing. The gap defines a serpentine insufflation chamber through which the insufflation gas passes on a tortuous path from the gas source through the filtration module to exit the insufflator through the one or more diffuser holes.

[0014] It should be understood that the protrusions can take many forms of various sizes and shapes without departing from the spirit of the present invention. For example, the protrusions can be dimples that form bumps but do not penetrate the single body of the filter module, elongated dimples, ridges, or angled flaps made by piercing the single body (creating holes in the form of slits) and bending the flaps at an angle to achieve a desired height. As long as the plurality of protrusions are of sufficient number, size, and height and are sufficiently dispersed to maintain the gaps that define the spiral plenum, the protrusions perform their function while strengthening the layers of the filter module. Of course, having more protrusions will dictate that the flow of the inflation gas that must move around such protrusions takes a more tortuous path to exit the inflator; however, the number, size, and distribution of the protrusions and holes can be adjusted and fine-tuned to optimize the desired amount of flow restriction, the desired amount of cooling, and / or the desired amount of impurities trapped for filling the airbag in the most material and cost efficient manner. Since the desired amount of flow restriction, the desired amount of cooling, and / or the desired amount of impurities trapped for filling the airbag depend on the size, shape, location, and desired rate of deployment, the number, size, and distribution of the protrusions and holes should be adjusted and fine-tuned to optimize the effectiveness of the filter module.

[0015] In some embodiments, the holes of the first array of holes in the inner layer are each larger than the holes of the second array of holes in the middle layer. By enlarging the holes in the first array of holes in the inner layer, the undesired erosion of the middle layer where the hot inflation gas directly impinges against the inner wall of the middle layer through the holes of the first array of holes is minimized. The size of the holes of the first array of holes can be enlarged until erosion is no longer observed. Similarly, the holes of the second array of holes can also be enlarged to avoid erosion on the outer layer of the filter module.

[0016] Additionally, the desired choke point in the flow of inflation gas through the inflator can be determined by adjusting the number and / or size of the holes in the first array of holes, the second array of holes, and the third array of holes, as well as the number and / or size of the diffuser holes.

[0017] Before the single body of the filter module is formed into a generally tubular shape in the form of a wound spiral by being formed around a correctly sized mandrel or otherwise, the single body is generally flat and, in some embodiments, has a length and width of a rectangular shape. The first array of holes in the single body is arranged in a first grid such that each hole in the first array of holes is longitudinally aligned with at least one other hole in the first array of holes and is also transversely aligned with at least one different hole in the first array of holes. In one exemplary embodiment, the first array of holes is arranged in the first grid with each row of longitudinally aligned holes having the same number of holes and each row of transversely aligned holes having the same number of holes.

[0018] The second array of holes is arranged in the second grid such that each hole in the second array of holes is longitudinally aligned with at least one other hole of the second array of holes and is also transversely aligned with at least one different hole in the second array of holes. However, the holes that are longitudinally aligned in the first array of holes are not longitudinally aligned with the holes that are longitudinally aligned in the second array of holes. This misalignment causes the flow of insufflation gas to turn and travel axially prior to passing through the second array of holes. In another exemplary embodiment, the second array of holes is arranged in the second grid with each row of longitudinally aligned holes having the same number of holes and each row of transversely aligned holes having the same number of holes.

[0019] The third array of holes is arranged in the third grid such that each hole in the third array of holes is longitudinally aligned with at least one other hole of the third array of holes and is also transversely aligned with at least one different hole in the third array of holes. The holes that are longitudinally aligned in the third array of holes are not longitudinally aligned with the holes that are longitudinally aligned in the second array of holes. This misalignment causes the flow of insufflation gas to turn and travel axially prior to passing through the third array of holes. In yet another exemplary embodiment, the third array of holes is arranged in the third grid with each row of longitudinally aligned holes having the same number of holes and each row of transversely aligned holes having the same number of holes.

[0020] In another exemplary embodiment, one or more of the first array of holes, the second array of holes, and the third array of holes has a staggered array pattern. An exemplary staggered array pattern can have a plurality of rows of longitudinally aligned holes, where each hole in any row of the plurality of rows of longitudinally aligned holes is also transversely aligned with at least one hole in another row of the plurality of rows of longitudinally aligned holes, but is not transversely aligned with any of the holes of at least another row of the plurality of rows of longitudinally aligned holes.

[0021] In some embodiments, the single body of the filter module is wider at the outer layer than at the inner and middle layers. When wrapped into a spiral, the outer layer is longer at one end than the inner and middle layers. Because the inner diameter of the outer layer is larger than the inner diameter of the inner layer, more space is provided at that end. For an insufflator having a frangible burst septum disposed between the gas source and the filter module, the burst septum has a larger diameter opening capability than if the inner layer abutted the burst septum. This wider configuration of the outer layer enables the burst septum to open over the full inner diameter of the outer layer. Other applications can require one or more of the inner or middle layers to be wider than the other layers for various reasons.

[0022] Exemplary embodiments of the present disclosure include a single filter module for insertion into an inflator of an airbag assembly. Inflators having an elongated housing with a central longitudinal axis are particularly suitable. Such inflators typically have at least one diffuser orifice and a gas source contained within a chamber defined within the housing. In response to an activation signal, the gas source provides a gas. Such inflators can use compressed gas, a pyrotechnic charge, or a mixture thereof. Such inflators also often have a filter to slow the flow of gas, cool the gas, and filter out impurities.

[0023] Exemplary embodiments of the single filter module of the present disclosure have a flat pattern for pre-making a single body of the filter module to be wrapped into a spiral wound configuration for insertion into the housing of an inflator (referred to herein as the "insertion spiral wound pattern"). The single body has a length (longitudinal direction) and a width (lateral direction) and is generally divided into an inner layer portion, a middle layer portion, and an outer layer portion.

[0024] In the flat pattern, the inner layer portion is made with a first array of holes arranged in a first grid. The first grid can have any of a number of patterns, but one exemplary pattern of holes is arranged so that each hole in the first array of holes is longitudinally aligned with at least one other hole of the first array of holes and is also laterally aligned with at least one different hole of the first array of holes. The middle layer portion includes a second array of holes arranged in a second grid. The second grid need not have the same number, pattern, or size of holes as the first array of holes. However, for simplicity, one exemplary embodiment has a pattern of holes where each hole in the second array of holes is longitudinally aligned with at least one other hole of the second array of holes and is also laterally aligned with at least one different hole of the second array of holes. However, the holes that are longitudinally aligned in the first array of holes are not longitudinally aligned with the holes that are longitudinally aligned in the second array of holes. This misalignment will cause the inflation gas to be redirected after passing through the first array of holes of the inner layer portion.

[0025] The outer layer portion includes a third array of holes arranged in a third grid. The third grid can be the same as the first grid, but need not be. An exemplary embodiment of the third grid has a pattern of holes where each hole in the third array of holes is longitudinally aligned with at least one other hole of the third array of holes and is also laterally aligned with at least one different hole of the third array of holes. However, the holes that are longitudinally aligned in the third array of holes are not longitudinally aligned with the holes that are longitudinally aligned in the second array of holes. Again, this misalignment will cause the inflation gas to be redirected after passing through the second array of holes of the middle layer portion.

[0026] A single body in a pre-prepared inserted helical wound pattern (see description above) can be formed by wrapping the single body around a mandrel of the correct size or by other suitable means. When wrapped, the filter module does not need to be welded to maintain its shape once inserted into the inflator. Upon insertion, the filter module is coaxial with the central longitudinal axis of the housing of the inflator in a wound helical manner. When disposed in the housing, the filter module comprised of the helical single body has a configuration such that the inner layer portions define the inner layer, the middle layer portions define the middle layer, and the outer layer portions define the outer layer.

[0027] In one example embodiment, the first array of holes of the inner layer portions surrounds the central longitudinal axis such that the longitudinally aligned holes of the first array of holes define a first set of planes each substantially perpendicular to the central longitudinal axis. This occurs because the single body has been wound about the transverse axis and then placed within the inflator such that the transverse axis of the wound single body is aligned with, or at least parallel to and in close proximity to, the central longitudinal axis of the inflator housing. Thus, the transversely aligned holes of the first array of holes define a first set of axes each substantially parallel to the central longitudinal axis. The inner layer is positioned such that gas passes through the first array of holes to reach the middle layer.

[0028] Similarly, the second array of holes of the middle layer portions surrounds the inner layer and the central longitudinal axis. Thus, the longitudinally aligned holes of the second array of holes define a second set of planes each substantially perpendicular to the central longitudinal axis and each offset from the first set of planes. The transversely aligned holes of the second array of holes define a second set of axes each substantially parallel to the central longitudinal axis. The middle layer is positioned such that gas passes through the second array of holes to reach the outer layer.

[0029] The third array of holes of the outer layer surrounds the inner layer, the middle layer, and the central longitudinal axis. The longitudinally aligned holes of the third array of holes define a third set of planes each substantially perpendicular to the central longitudinal axis and each offset from the second set of planes. The transversely aligned holes of the third array of holes define a third set of axes each substantially parallel to the central longitudinal axis. The outer layer is positioned such that the inflation gas passes through the third array of holes to reach the inner wall of the housing and the at least one diffuser hole.

[0030] As disclosed herein, the middle layer includes a second array of holes each of which is not aligned with a hole of the first array of holes closest to such hole of the second array of holes. Thus, the middle layer is positioned such that the inflation gas is reoriented to move axially before passing through the second array of holes to reach the outer layer. The outer layer includes a third array of holes each of which is not aligned with a hole of the second array of holes closest to such hole of the third array of holes. Likewise, the outer layer is positioned such that the inflation gas is reoriented to move axially before passing through the third array of holes to reach the at least one diffuser hole of the housing.

[0031] Each example embodiment of the filter module has a plurality of protrusions. The protrusions are disposed such that the inner layer portion (and thus the inner layer) has at least one protrusion, the intermediate layer portion (and thus the intermediate layer) has at least one protrusion, and the outer layer portion (and thus the outer layer) has at least one protrusion. Each protrusion disposed on the inner layer portion is adjacent to at least one of the holes of the first array of holes of the inner layer. Each protrusion disposed on the intermediate layer portion is adjacent to at least one of the holes of the second array of holes of the intermediate layer. Each protrusion disposed on the outer layer portion is adjacent to at least one of the holes of the third array of holes of the outer layer. Such protrusions maintain a gap between the inner layer and the intermediate layer, between the intermediate layer and the outer layer, and between the outer layer and the outer wall to define a spiral plenum through which the insufflation gas passes from the gas source through the filter module in a tortuous path to be expelled through at least one diffuser hole in the insufflator.

[0032] In example embodiments of the single filter module of the present disclosure, the holes can be arranged in a staggered pattern. The staggered pattern can be incorporated into the first array of holes in the inner layer, the second array of holes in the intermediate layer, and / or the third array of holes in the outer layer. One example of a staggered pattern has a plurality of rows of longitudinally aligned holes, and each hole in any one of the plurality of rows of longitudinally aligned holes is transversely aligned with at least one hole in another one of the plurality of rows of longitudinally aligned holes, but not with any of the holes in at least one other one of the plurality of rows of longitudinally aligned holes.

[0033] These and other features and advantages of the example embodiments of the present disclosure will become more apparent from the following detailed description and accompanying claims as set forth below, or can be learned by practice of the application as set forth hereinafter.

[0034] Reference Numerals BRIEF DESCRIPTION OF DRAWINGS

[0035] Example embodiments of the application will become more fully understood from the following description and the accompanying drawings, in which: Figure 1 is a perspective view of an example embodiment of a single body of a filter module in a flat mode, showing protrusions adjacent to holes; Figure 2 is a perspective view of an example single body of Figure 1 is a plan view of an example single body of Figure 3 is a perspective view of an example single body of Figure 1perspective view of an exemplary single body; Figure 4 is a partial cross-sectional view of an inflator having a filter module inserted therein and showing an exemplary inflator gas flow path; Figure 5 is a plan view of an exemplary single body in a flat mode and showing exemplary longitudinal and transverse lines; Figure 6 is a plan view of an alternative exemplary single body in a flat mode and showing exemplary staggered transverse lines; Figure 7 is a plan view of another exemplary single body in a flat mode and showing exemplary transverse elongated protrusions arranged in staggered transverse lines; Figure 8 is a longitudinal cross-sectional view of the single body of Figure 7 showing a spiral inflation chamber; Figure 9 is a plan view of yet another exemplary single body in a flat mode and showing an example of different aperture sizes; Figure 10 is a partial cross-sectional view of an inflator having a filter module inserted in a spiral wound mode within an inflator housing; Figure 11 is a partial cross-sectional view of an inflator having a filter module inserted in a spiral wound mode within an inflator housing similar to Figure 10 except that it has a wider filter module so as to create a larger diameter for the burst diaphragm rupture; and Figure 12 is a partial cross-sectional view of an inflator having an alternative exemplary filter module inserted in a spiral wound mode within an inflator housing, wherein each aperture forms a slanted fin that acts as a protrusion. DETAILED DESCRIPTION

[0036] The exemplary embodiments of this application will be best understood by reference to the accompanying drawings, wherein like reference numerals refer to like parts throughout. It should be readily appreciated that the components of the application described and illustrated herein can be arranged and designed in a wide variety of different configurations. Thus, the following more detailed description of the exemplary embodiments of the apparatus, systems, and methods of the application is not intended to limit the scope of the application, as claimed, but is merely representative of the exemplary embodiments of the application. Figures 1 to 4 The following more detailed description of the exemplary embodiments of the devices, systems and methods of the application, as illustrated in the drawings, is not intended to limit the scope of the application, as claimed, but is merely representative of the exemplary embodiments of the application.

[0037] The phrases "connected to," "coupled to" and "in communication with" refer to any form of interaction between two or more entities, including mechanical, electrical, magnetic, electromagnetic, fluid, and thermal interaction. Two components can be coupled to each other even though they are not in direct contact with each other. The term "abutting" refers to items that are in direct physical contact with each other, but the items can not necessarily be attached together. The phrase "fluid communication" means that two features are connected such that fluid expelled from one feature can enter or otherwise contact the other feature.

[0038] The word "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any implementation described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other implementations. Although aspects of implementations can be illustrated with reference to particular elements and / or embodiments, the drawings are not necessarily drawn to scale and that unless specifically stated otherwise, the drawings are not to be interpreted in accordance with the drawings.

[0039] The word "unitary" is used herein to mean a single unit. Such a unit can be made of a piece of material, but not necessarily. A single unit can be formed from more than one piece of material. The material of the single unit is not necessarily the same throughout the single unit. The material of the single unit can be the same or different in different regions of the single unit.

[0040] Inflatable airbag systems are widely used to minimize occupant injury in crash situations. Airbag modules have been installed in various locations within a vehicle, including but not limited to the steering wheel, the instrument panel, within the side door or side seat, adjacent to the vehicle's roof rail, in an overhead position, or at a knee or leg position. In the following disclosure, "airbag" can refer to any airbag type.

[0041] See Figure 1 , Figure 2 and Figure 5 An exemplary embodiment of the single body 12 of the filtration module 10 is shown in a flat pattern. The single body 12 has a length L (longitudinal direction 14) and a width W (transverse direction 16), and is generally divided into an inner layer portion 18, a middle layer portion 20, and an outer layer portion 22.

[0042] In the flat pattern, the inner layer portion 18 is prepared with a first array of holes 24 arranged in a first grid 26. The first grid 26 can have any of a number of patterns, but one exemplary pattern of holes is arranged such that each hole 28 in the first array of holes 24 is longitudinally aligned with at least one other hole in the first array of holes 24, and is also transversely aligned with at least one different hole of the first array of holes 24. The middle layer portion 20 includes a second array of holes 30 arranged in a second grid 32. The second grid 32 need not have the same number, pattern, or size of holes as the first array of holes 24.

[0043] While example embodiments are disclosed herein, not all possible arrays will be disclosed herein for the sake of brevity. One of skill in the art having the benefit of the instant disclosure can make and prepare many different arrays of holes that will not depart from the spirit of the disclosure. Additionally, a single intermediate layer portion 20 is shown throughout the drawings for the sake of brevity and so as not to obscure the disclosed features. However, it should be understood that there can be more than one intermediate layer portion 20 and that the intermediate layer does not necessarily need to have the same array of holes.

[0044] Figure 5 One example embodiment shown has a pattern of holes where each hole 34 in the second array of holes 30 is longitudinally aligned with at least one other hole 34 of the second array of holes 30 and is also transversely aligned with at least one different hole 34 of the second array of holes 30. However, the holes 28 that are longitudinally aligned in the first array of holes 24 are not longitudinally aligned with the holes 34 that are longitudinally aligned in the second array of holes 30. This misalignment will result in the inflation gas being redirected after passing through the first array of holes 24 of the inner layer portion 18.

[0045] The outer layer portion 22 includes a third array of holes 36 arranged in a third grid 38. The third grid 38 can be the same as the first grid 26, but need not be. One example embodiment of the third grid 38 has a pattern of holes where each hole 40 in the third array of holes 36 is longitudinally aligned with at least one other hole 40 of the third array of holes 36 and is also transversely aligned with at least one different hole 40 of the third array of holes 36. However, the holes 40 that are longitudinally aligned in the third array of holes 36 are not longitudinally aligned with the holes 34 that are longitudinally aligned in the second array of holes 34. Again, this misalignment will result in the inflation gas being redirected after passing through the second array of holes 34 of the intermediate layer portion 20.

[0046] Each example embodiment of the filter module 10 has a plurality of protrusions 42. These protrusions 42 are arranged so that the inner layer portion 18 has at least one protrusion 42 and possibly several, the intermediate layer portion 20 has at least one protrusion 42 and possibly several, and the outer layer portion 22 has at least one protrusion 42 and possibly several. Each protrusion 42 arranged on the inner layer portion 18 is adjacent to at least one of the holes 28 of the first array of holes 24 of the inner layer portion 18. Each protrusion 42 arranged on the intermediate layer portion 20 is adjacent to at least one of the holes 34 of the second array of holes 30 of the intermediate layer portion 20. Each protrusion 42 arranged on the outer layer portion 22 is adjacent to at least one of the holes 40 of the third array of holes 36 of the outer layer portion 22. Such protrusions 42 are designed and positioned to maintain the gap between the inner and intermediate layers, the intermediate and outer layers, and the outer layer and the outer wall (in the case of a filter module 10 having an outer wall) as the filter module 10 is used. The protrusions 42 can be arranged in any pattern desired. For example, the protrusions 42 can be arranged in a grid pattern, a staggered pattern, a random pattern, or any other pattern desired. Figure 1 、 Figure 2 andFigure 5 Not shown in the image, see [link / reference]. Figure 3 , Figure 4 , Figure 8 , Figure 10 and Figure 11 ( ), to define a spiral inflation chamber through which inflation gas passes from a gas source through a filter module in a tortuous path to be discharged through at least one diffuser hole in the inflator 44.

[0047] pass Figure 5 In the exemplary embodiment shown, each protrusion 42 is longitudinally aligned with at least one other protrusion 42 along a longitudinal line. Such a longitudinal line within the second hole array 30 passes through the hole 34 and the protrusion, and is shown as longitudinal line 43. Another such longitudinal line within the third hole array 36 passes through the hole 40 and the protrusion 42, and is shown as longitudinal line 45. The longitudinal lines of the second hole array 30 (longitudinal line 43 being one of them) are not aligned with any of the longitudinal lines of the first hole array 24 or the third hole array 36 (longitudinal line 45 being one of them).

[0048] Similarly, in Figure 5 In the middle section 20, each protrusion 42 is laterally aligned with at least one other protrusion 42. Such a lateral line is shown as lateral line 47 in the middle section 20, and another lateral line is shown as lateral line 49 in the outer section 22. This lateral alignment, which matches the longitudinal misalignment of the holes 28, 34, 40, effectively ensures that the holes 28, 34, 40 do not align layer by layer from the filter module 10. Therefore, the flow of inflatable gas through the filter module 10 will necessarily travel along a tortuous path.

[0049] Similarly, it should be understood that the protrusion 42 may take on various forms and sizes without departing from the spirit of this disclosure. For example, the protrusion 42 may be a recess 51 forming a raised area but not penetrating the single body 12 of the filter module 10 (see also...). Figure 5 and Figure 6 ), elongation pit 53 (see Figure 7 and Figure 9 ), ridge, or inclined wing 55 made by piercing a single body 12 (forming a slit-like hole) and bending the wing 55 at the incline to achieve the desired height (see Figure 12). So long as the plurality of protrusions 42 are of sufficient number, size, and height and are sufficiently dispersed to maintain the gaps 58 that define the spiral plenum 60, the protrusions 42 serve their purpose while reinforcing the layers 48, 50, 52 of the filter module 10. Of course, having more protrusions 42 will dictate that the flow of inflation gas that must move around such protrusions 42 will take a more tortuous path to exit the inflator 44; however, the number, size, and distribution of the protrusions 42 and the apertures 28, 34, 40 can be adjusted, and can be fine-tuned, to optimize the desired amount of flow restriction, the desired amount of cooling, and / or the desired amount of impurities captured for filling the airbag in the most material- and cost-efficient manner. Since the desired amount of flow restriction, the desired amount of cooling, and / or the desired amount of impurities captured for filling the airbag depends on the size, shape, location, and desired rate of deployment of the airbag, the number, size, and distribution of the protrusions 42 and the apertures 28, 34, 40 should be adjusted and fine-tuned to optimize the effectiveness of the filter module 10 used in each type of inflator.

[0050] In advance of preparation (see Figure 1 , Figure 2 and Figure 5 ), the unitary body 12 can be converted into an insert spiral wound pattern by wrapping the unitary body 12 around a mandrel (not shown) of the correct size or by other suitable means. Prior to insertion into the inflator 44 and after forming the unitary body 12 into a wound spiral of generally tubular shape, the filter module 10 looks as shown in Figure 3 . In being wound, the filter module 10 does not require welding to maintain its shape once inserted into the inflator 44. In being inserted, the filter module 10 is coaxial with the central longitudinal axis A of the housing 46 of the inflator 44 in the wound spiral, as shown in Figure 4 . When disposed in the housing 46, the filter module 10 has the spiral unitary body 12 with a configuration such that the inner layer portion 18 defines the inner layer 48, the intermediate layer portion 20 defines the intermediate layer 50, and the outer layer portion 22 defines the outer layer 52, as shown in Figure 3 and Figure 4 .

[0051] Also, for the sake of brevity and thus not to obscure the disclosed features, a single intermediate layer portion 20 and a single intermediate layer 50 are shown throughout the drawings. However, it should be understood that there can be more than one intermediate layer portion 20, more than one intermediate layer 50, and that the intermediate layer 50 need not necessarily have the same array of apertures.

[0052] In one exemplary embodiment, the first array of apertures 24 of the inner layer portion 18 is about the central longitudinal axis A such that the longitudinally-aligned apertures 28 of the first array of apertures 24 define a first set of planes PI that are each substantially perpendicular to the central longitudinal axis A (see, e.g.,Figure 4 and Figure 8 ). This occurs because the single body 12 has been wrapped about the transverse axis and then placed within the inflator such that the transverse axis of the wrapped single body is aligned with, or at least parallel to and in close proximity to, the central longitudinal axis A of the inflator housing 46. Thus, the transversely aligned holes 28 of the first hole array 24 define a first set of axes LI that are substantially parallel to the central longitudinal axis A (see, e.g., FIG. 2). Figure 4 and Figure 8 ). The inner layer 48 is positioned such that the inflation gas G passes through the first hole array 24 to reach the intermediate layer 50.

[0053] Similarly, the second hole array 30 of the intermediate layer portion 20 surrounds the inner layer 48 and the central longitudinal axis A. Thus, the longitudinally aligned holes 34 of the second hole array 30 define a second set of planes P2 that are each substantially perpendicular to the central longitudinal axis A and each offset from the first set of planes PI. The transversely aligned holes 34 of the second hole array 30 define a second set of axes L2 that are substantially parallel to the central longitudinal axis A. The intermediate layer 50 is positioned such that the inflation gas G passes through the second hole array 30 to reach the outer layer 52.

[0054] The third hole array 36 of the outer layer 52 surrounds the inner layer 48, the intermediate layer 50, and the central longitudinal axis A. The longitudinally aligned holes 40 of the third hole array 36 define a third set of planes P3 that are each substantially perpendicular to the central longitudinal axis A and each offset from the second set of planes P2. The transversely aligned holes 40 of the third hole array 36 define a third set of axes L3 that are substantially parallel to the central longitudinal axis A. The outer layer 52 is positioned such that the inflation gas G passes through the third hole array 36 to reach the inner wall 54 of the housing 46 and the at least one diffuser hole 56.

[0055] As disclosed in at least one exemplary embodiment herein (best shown in FIG. 2), the intermediate layer 50 includes the second hole array 30, each hole 34 of which is not aligned with the hole 28 of the first hole array 24 that is closest to such hole 34 of the second hole array 30. Thus, the intermediate layer 50 is positioned such that the inflation gas G is reoriented to move axially before passing through the second hole array 30 to reach the outer layer 52. The outer layer 54 includes the third hole array 36, each hole 40 of which is not aligned with the hole 34 of the second hole array 30 that is closest to such hole 40 of the third hole array 54. Likewise, the outer layer 52 is positioned such that the inflation gas G is reoriented to move axially before passing through the third hole array 36 to reach the at least one diffuser hole 56 of the housing 46. Figure 4

[0056] ​Each example embodiment of the filter module 10 has a plurality of protrusions 42. These protrusions 42 are disposed such that the inner layer portion 18 (and thus the inner layer 48) has at least one protrusion 42, the middle layer portion 20 (and thus the middle layer 50) has at least one protrusion 42, and the outer layer portion 22 (and thus the outer layer 52) has at least one protrusion 42. Each protrusion 42 disposed on the inner layer portion 18 is adjacent to at least one of the holes 28 of the first array of holes 24 of the inner layer 48. Each protrusion 42 disposed on the middle layer portion 20 is adjacent to at least one of the holes 34 of the second array of holes 30 of the middle layer 50. Each protrusion 42 disposed on the outer layer portion 22 is adjacent to at least one of the holes 40 of the third array of holes 36 of the outer layer 52. Such protrusions maintain the gaps 58 between the inner layer 48 and the middle layer 50, between the middle layer 50 and the outer layer 52, and between the outer layer 52 and the inner wall 54 of the housing 46 to define the spiral plenum 60 through which the inflation gas G passes from the gas source 62 through the filter module 10 to be expelled through at least one diffuser hole 46 in the inflator 46 (best understood by the flow arrows 61 shown in FIGS. 1-3). Figure 4 and Figure 12

[0057] So long as the plurality of protrusions 42 are of sufficient number, size, and height and are sufficiently dispersed to maintain the gaps 58 defining the spiral plenum 60, the protrusions 42 serve their purpose while strengthening the layers 48, 50, 52 of the filter module 10. Of course, having more protrusions will dictate that the flow of inflation gas G that must move around such protrusions 42 takes a more tortuous path to be expelled from the inflator 44. However, the number, size, and distribution of the protrusions 42 and the holes 28, 34, 40 can be adjusted and fine-tuned to optimize the desired amount of flow restriction, the desired amount of cooling, and / or the desired amount of impurities captured for filling the airbag in the most material- and cost-efficient manner. Since the desired amount of flow restriction, the desired amount of cooling, and / or the desired amount of impurities captured for filling the airbag depends on the size, shape, location, and desired rate of deployment of the airbag, the number, size, and distribution of the protrusions 42 and the holes 28, 34, 40 should be adjusted and fine-tuned to optimize the effectiveness of the filter module 10.

[0058] In some embodiments, such as Figure 9 ​As shown, the holes 28 of the first hole array 24 in the inner layer 48 are each larger than the holes 34 of the second hole array 30 in the intermediate layer 50. By enlarging the holes 28 in the first hole array 24 in the inner layer 48, undesirable corrosion of the intermediate layer 50 can be mitigated because the flow 61 of the hot-filled gas G is sprayed directly through the holes 28 of the first hole array 24 against the inner wall of the intermediate layer 50. The size of the holes 28 of the first hole array 24 can be enlarged until corrosion is no longer observed. Similarly, the holes 34 of the second hole array 30 can also be enlarged to avoid corrosion on the outer layer 52 of the filter module 10.

[0059] Additionally, the desired blockage point in the flow 61 of the inflation gas G through the inflator 44 can be determined by adjusting the number and / or size of the holes 28, 34, and 40 in the first hole array 24, the second hole array 30, and the third hole array 36, as well as the number and / or size of the diffuser holes 56.

[0060] In an exemplary embodiment of the single filtering module 10 of this disclosure, such as Figure 6 , Figure 7 and Figure 9 As shown, holes 28, 34, 40 and protrusion 42 can be arranged in a staggered pattern 64. This staggered pattern 64 can be incorporated into a first hole array 24 in the inner layer 48, a second hole array 30 in the intermediate layer 50, and / or a third hole array 36 in the outer layer 52. An example of the staggered pattern 64 has multiple rows of longitudinally aligned holes, and each hole in any row of the multiple rows of longitudinally aligned holes is laterally aligned with at least one hole in another row of the multiple rows of longitudinally aligned holes, but not laterally aligned with any hole in at least one other row of the multiple rows of longitudinally aligned holes.

[0061] In some implementations, such as Figure 11 As shown, the single body 12 of the filter module 10 is wider at the outer layer 52 than at the inner layer 48 and the middle layer 50. (Provided) Figure 10 For comparison, each layer 48, 50, and 52 has the same width. When wrapped in a spiral, the outer layer 52 is longer at one end than the inner layer 48 and the middle layer 50. Since the inner diameter 68 of the outer layer 52 is larger than the inner diameter 70 of the inner layer 48, more space 66 is provided at that end. For an inflator 44 with a fragile burst diaphragm 72 positioned between the gas source 62 and the filter module 10, the burst diaphragm 72 has a larger diameter opening capacity than if the inner layer 48 were adjacent to the burst diaphragm 72. This wider configuration of the outer layer 52 allows the burst diaphragm 72 to open across its full inner diameter 68.

[0062] Any method disclosed herein includes one or more steps or actions for performing the described method. The steps and / or actions of this method are interchangeable. In other words, the order and / or usage of specific steps and / or actions may be changed unless a specific order of steps or actions is required for proper implementation.

[0063] Throughout this specification, the terms "implementation" or "this implementation" are meant to refer to a particular feature, structure, or characteristic described in connection with that implementation, which is included in at least one implementation. Therefore, not all references or variations thereof throughout this specification necessarily refer to the same implementation.

[0064] Similarly, it should be understood that in the foregoing description of the embodiments, various features are sometimes grouped together in a single embodiment, drawing, or description therein for the purpose of simplifying this disclosure. However, this approach of the disclosure should not be construed as reflecting an intention that any claim requires more features than those expressly recited in that claim. Rather, as reflected in the following claims, the inventive aspect lies in a combination of features fewer than all features of any single foregoing disclosed embodiment. Therefore, the claims following this specific embodiment are thus expressly incorporated into this specific embodiment, wherein each claim is itself a separate embodiment. This disclosure includes all permutations of the independent claims and their dependent claims.

[0065] The term "first" used in the claims to describe a feature or element does not necessarily imply the presence of a second or additional such feature or element. Elements described in the means-plus-function format are intended to be interpreted in accordance with paragraph 6 of 35 USC §112. It will be apparent to those skilled in the art that changes may be made to the details of the above embodiments without departing from the fundamental principles of the invention.

[0066] While specific embodiments and applications of the invention have been described and illustrated, it should be understood that the invention is not limited to the precise configurations and components disclosed herein. Various modifications, alterations, and variations that will be apparent to those skilled in the art may be made in the arrangement, operation, and details of the methods and systems disclosed herein without departing from the spirit and scope of the invention.

Claims

1. An inflator for an airbag assembly used to protect vehicle occupants from injury, the inflator comprising: A housing having a central longitudinal axis and including at least one diffuser hole; A gas source, comprising a chamber defined within the housing, wherein, in response to the inflator receiving a first activation signal, the gas source supplies gas; and A filter module comprising a single body wound into a generally tubular spiral around a central longitudinal axis and disposed within the housing to define an inner layer, a middle layer, and an outer layer, wherein: The inner layer includes a first aperture array, wherein the inner layer is positioned such that the gas passes through the first aperture array to reach the intermediate layer; The intermediate layer includes a second aperture array, each aperture in the second aperture array being not aligned with the aperture in the first aperture array that is closest to such an aperture in the second aperture array, wherein the intermediate layer is positioned such that the gas passes through the second aperture array to reach the outer layer; The outer layer includes a third aperture array, each aperture in the third aperture array not aligned with the closest such aperture in the second aperture array, wherein the outer layer is positioned such that the gas passes through the third aperture array to reach the at least one diffuser aperture on the outer wall; and A plurality of protrusions, at least one of which is adjacent to at least one of the holes in the first hole array of the inner layer, at least one of which is adjacent to at least one of the holes in the second hole array of the intermediate layer, and at least one of which is adjacent to at least one of the holes in the third hole array of the outer layer, each protrusion of the inner layer protruding toward the intermediate layer, each protrusion of the intermediate layer protruding toward the outer layer, and each protrusion of the outer layer protruding toward the outer wall, such protrusions maintaining gaps between the inner and intermediate layers, between the intermediate and outer layers, and between the outer layer and the outer wall to define a spiral inflation chamber through which gas passes from the gas source through the filter module in a tortuous path to exit the inflator through the at least one diffuser hole.

2. The inflator according to claim 1, wherein the protrusion is a recess.

3. The inflator according to claim 2, wherein each recess is laterally elongated.

4. The inflator of claim 1, wherein the holes of the first hole array, the holes of the second hole array, and the holes of the third hole array are formed by piercing the single body, such that each hole forms an inclined flap serving as one of the plurality of protrusions.

5. The inflator according to claim 1, wherein each of the holes in the first hole array is larger than the holes in the second hole array.

6. The inflator of claim 1, wherein a blockage point in the flow of gas through the inflator is determined by adjusting the number of holes in the first hole array, the second hole array, and the third hole array, as well as the number of diffuser holes.

7. The inflator of claim 1, wherein a blockage point in the flow of gas through the inflator is determined by adjusting the size of the holes in the first hole array, the second hole array, and the third hole array, as well as the size of the at least one diffuser hole.

8. The inflator of claim 1, wherein the single body has a length and a width, and wherein: The first hole array is arranged in the first grid such that each hole in the first hole array is longitudinally aligned with at least another hole in the first hole array, and is also laterally aligned with at least one different hole in the first hole array; The second hole array is arranged in the second grid such that each hole in the second hole array is longitudinally aligned with at least another hole in the second hole array, and is also laterally aligned with at least one different hole in the second hole array, wherein the hole longitudinally aligned in the first hole array is not longitudinally aligned with the hole longitudinally aligned in the second hole array. and The third hole array is arranged in the third grid such that each hole in the third hole array is longitudinally aligned with at least another hole in the third hole array, and is also laterally aligned with at least one different hole in the third hole array, wherein the longitudinally aligned hole in the third hole array is not longitudinally aligned with the hole that is longitudinally aligned in the second hole array. When the filter module is disposed in the housing: The first hole array of the inner layer surrounds the central longitudinal axis such that the longitudinal alignment holes in the first hole array define a first set of planes that are substantially perpendicular to the central longitudinal axis, and the transverse alignment holes in the first hole array define a first set of axes that are substantially parallel to the central longitudinal axis. The second aperture array of the intermediate layer surrounds the inner layer and the central longitudinal axis, such that the longitudinal alignment holes in the second aperture array define a second set of planes that are each substantially perpendicular to the central longitudinal axis and offset from the first set of planes, and the transverse alignment holes in the second aperture array define a second set of axes that are substantially parallel to the central longitudinal axis; and The third aperture array of the outer layer surrounds the inner layer, the intermediate layer, and the central longitudinal axis, such that the longitudinal alignment apertures in the third aperture array define a third set of planes that are substantially perpendicular to the central longitudinal axis and offset from the second set of planes, and the transverse alignment apertures in the third aperture array define a third set of axes that are substantially parallel to the central longitudinal axis.

9. The inflator of claim 1, wherein at least one of the first hole array, the second hole array, and the third hole array has an interlaced array pattern, wherein the interlaced array pattern comprises multiple rows of longitudinally aligned holes, and each hole in any row of the multiple rows of longitudinally aligned holes is laterally aligned with at least one hole in another row of the multiple rows of longitudinally aligned holes, but not laterally aligned with any hole in at least one other row of the multiple rows of longitudinally aligned holes.

10. The inflator of claim 1, wherein the single body of the filter module is wider at the outer layer than at the inner and intermediate layers, and the inflator has a fragile burst diaphragm between the gas source and the filter module, such that the burst diaphragm can be opened over the full diameter of the outer layer.

11. A single module in an inflator for inserting into an airbag assembly, the inflator having a housing with a central longitudinal axis, at least one diffuser orifice, and a gas source contained within a chamber defined within the housing, wherein, In response to the inflator receiving a first activation signal, the gas source supplies gas, the single filter module has a flat mode and an inserted spiral winding mode, and includes: A single entity, having length, width, inner layer, middle layer, and outer layer, in the flat mode: The inner layer portion includes a first hole array arranged in a first grid such that each hole in the first hole array is longitudinally aligned with at least another hole in the first hole array, and is also laterally aligned with at least one different hole in the first hole array. The intermediate layer portion includes a second aperture array arranged in the second grid such that each aperture in the second aperture array is longitudinally aligned with at least one other aperture in the second aperture array, and also laterally aligned with at least one different aperture in the second aperture array, wherein the aperture longitudinally aligned in the first aperture array is not longitudinally aligned with the aperture longitudinally aligned in the second aperture array; and The outer layer includes a third hole array arranged in a third grid such that each hole in the third hole array is longitudinally aligned with at least one other hole in the third hole array, and is also laterally aligned with at least one different hole in the third hole array, wherein the longitudinally aligned hole in the third hole array is not longitudinally aligned with the hole that is longitudinally aligned in the second hole array. The single body in the inserted spiral winding mode is wound into a spiral around the central longitudinal axis and disposed within the housing, such that the inner layer portion defines an inner layer, the middle layer portion defines a middle layer, and the outer layer portion defines an outer layer, wherein: The first aperture array of the inner layer surrounds the central longitudinal axis such that the longitudinal alignment apertures in the first aperture array define a first set of planes substantially perpendicular to the central longitudinal axis, and the transverse alignment apertures in the first aperture array define a first set of axes substantially parallel to the central longitudinal axis, and wherein the inner layer is positioned such that the gas passes through the first aperture array to reach the intermediate layer. The second aperture array of the intermediate layer surrounds the inner layer and the central longitudinal axis, such that the longitudinal alignment holes in the second aperture array define a second set of planes that are each substantially perpendicular to the central longitudinal axis and offset from the first set of planes, and the transverse alignment holes in the second aperture array define a second set of axes that are substantially parallel to the central longitudinal axis, and wherein the intermediate layer is positioned such that the gas passes through the second aperture array to reach the outer layer; and The outer layer's third aperture array surrounds the inner layer, the intermediate layer, and the central longitudinal axis, such that the longitudinal alignment apertures in the third aperture array define a third set of planes that are substantially perpendicular to the central longitudinal axis and offset from the second set of planes, and the lateral alignment apertures in the third aperture array define a third set of axes that are substantially parallel to the central longitudinal axis, and wherein the outer layer is positioned such that the gas passes through the third aperture array to reach the at least one diffuser aperture; The intermediate layer includes a second aperture array, each aperture in the second aperture array being not aligned with the aperture in the first aperture array that is closest to such an aperture in the second aperture array, wherein the intermediate layer is positioned such that the gas passes through the second aperture array to reach the outer layer; The outer layer includes a third aperture array, each aperture in the third aperture array not aligned with the closest such aperture in the second aperture array, wherein the outer layer is positioned such that the gas passes through the third aperture array to reach the at least one diffuser aperture of the housing; and A plurality of protrusions are configured such that at least one protrusion is disposed on the inner layer portion, at least one protrusion is disposed on the intermediate layer portion, and at least one protrusion is disposed on the outer layer portion. Each protrusion disposed on the inner layer portion is adjacent to at least one of the holes in the first hole array of the inner layer, each protrusion disposed on the intermediate layer portion is adjacent to at least one of the holes in the second hole array of the intermediate layer, and each protrusion disposed on the outer layer portion is adjacent to at least one of the holes in the third hole array of the outer layer. Such protrusions maintain gaps between the inner layer and the intermediate layer, between the intermediate layer and the outer layer, and between the outer layer and the outer wall to define a spiral inflation chamber through which gas passes from the gas source through the filter module in a tortuous path to exit the inflator through the at least one diffuser hole.

12. The filter module according to claim 11, wherein the protrusion is a recess.

13. The filter module of claim 12, wherein each recess is laterally elongated.

14. The filter module of claim 11, wherein the holes of the first hole array, the holes of the second hole array, and the holes of the third hole array are formed by piercing the single body, such that each hole forms an inclined wing serving as one of the plurality of protrusions.

15. The filter module of claim 11, wherein each of the pores in the first pore array is larger than the pores in the second pore array.

16. The filter module of claim 11, wherein a blockage point in the flow of gas through the inflator is determined by adjusting the number of holes in the first hole array, the second hole array, and the third hole array, as well as the number of diffuser holes.

17. The filter module of claim 11, wherein a blockage point in the flow of gas through the inflator is determined by adjusting the size of the holes in the first hole array, the second hole array, and the third hole array, as well as the size of the at least one diffuser hole.

18. The inflator of claim 11, wherein the single body of the filter module is wider at the outer layer portion than at the inner layer portion and the intermediate layer portion, and the inflator has a fragile burst diaphragm between the gas source and the filter module, such that the burst diaphragm can be opened over the full diameter of the outer layer.

19. A single filter module for insertion into an inflator of an airbag assembly, the inflator having a housing with a central longitudinal axis, at least one diffuser orifice, and a gas source contained within a chamber defined within the housing, wherein, In response to the inflator receiving a first activation signal, the gas source supplies gas, the single filter module has a flat mode and an inserted spiral winding mode, and includes: A single entity, having length, width, inner layer, middle layer, and outer layer, in the flat mode: The inner layer portion includes a first aperture array; The intermediate layer portion includes a second array of holes; The outer layer includes a third aperture array; A plurality of protrusions, at least one of which is adjacent to at least one of the holes in the first hole array of the inner layer portion, at least one of which is adjacent to at least one of the holes in the second hole array of the intermediate layer portion, and at least one of which is adjacent to at least one of the holes in the third hole array of the outer layer portion; and At least one of the first aperture array, the second aperture array, and the third aperture array has an interlaced array pattern, wherein the interlaced array pattern includes multiple rows of longitudinally aligned apertures, and each aperture in any row of the multiple rows of longitudinally aligned apertures is laterally aligned with at least one aperture in another row of the multiple rows of longitudinally aligned apertures, but not laterally aligned with any aperture in at least one other row of the multiple rows of longitudinally aligned apertures. The single body in the inserted spiral winding mode is wound into a spiral around the central longitudinal axis and disposed within the housing, such that the inner layer portion defines an inner layer, the middle layer portion defines a middle layer, and the outer layer portion defines an outer layer, wherein: The inner layer is positioned such that the gas passes through the first aperture array to reach the middle layer; The intermediate layer is positioned such that the gas passes through the second aperture array to reach the outer layer; The outer layer is positioned such that the gas passes through the third aperture array to reach the at least one diffuser aperture; and Each protrusion of the inner layer protrudes toward the intermediate layer, each protrusion of the intermediate layer protrudes toward the outer layer, and each protrusion of the outer layer protrudes toward the outer wall. These protrusions maintain gaps between the inner and intermediate layers, between the intermediate and outer layers, and between the outer layer and the outer wall to define a spiral inflation chamber through which gas passes from the gas source through the filter module in a tortuous path to exit the inflator through the at least one diffuser orifice.

20. The filter module of claim 19, wherein the protrusion is a recess.

Images