WO2024040064A1

WO2024040064A1 - Airbag diffuser

Info

Publication number: WO2024040064A1
Application number: PCT/US2023/072227
Authority: WO
Inventors: Brett M. Johnson; Thomas Joachim KOFLER; Randall J. Schoenborn; James R. Stone
Original assignee: Illinois Tool Works Inc.
Priority date: 2022-08-19
Filing date: 2023-08-15
Publication date: 2024-02-22

Abstract

Described is a diffuser (102) for use in an airbag assembly. The diffuser includes a shaft (112) and a fitting (110). The shaft has a first end (116 a) that is closed and a second end (116 b)that is open. The shaft includes or otherwise defines a first linear portion (112 a) oriented at an angle relative to a second linear portion (112 b). The first linear portion and the second linear portion are a unitary structure. The fitting is positioned at the second end of the shaft. The fitting is configured to couple to an inflator (104). At least one exhaust opening (114) is formed in the first linear portion. The shaft and the fitting are fluidly coupled to one another to expel exhaust gas from the inflator via the at least one exhaust opening.

Description

AIRBAG DIFFUSER

BACKGROUND

[0001] Inflatable airbags have been credited with preventing numerous vehicular deaths and injuries. Airbag assemblies are often distributed throughout the vehicle to mitigate contact between the occupant and vehicular structures during a collision. Airbag assemblies can be installed in the steering wheel, dashboard, doors, pillars, over the windows, etc.

[0002] Curtain airbags, for example, inflate and descend from an upper frame member to cover a majority of the area between the occupant and the side of the vehicle interior. The inflated airbag resembles a curtain covering the vehicle window Curtain airbags can protect the occupant from impact with a side window, flying shards of glass, and other projectiles. Curtain airbag may also help to keep the occupant inside the vehicle during a roll-over accident.

[0003] An inflator, which often uses a combination of compressed gas and solid fuel, is used to quickly inflate airbags, such as curtain airbag. Generally, the un-inflated curtain airbag is installed in a very limited thin space defined by the roof frame member. Accordingly, the inflator is often shaped as a thin, cylindrical member that extends a portion of the length of the curtain airbag. The curtain airbag inflator is capable of providing sufficient inflation gas to properly inflate the curtain airbag. The inflator is sometimes installed within the curtain airbag of the curtain airbag assembly. However, doing so generally requires that the inflator include a diffuser.

[0004] Gas that fills the curtain airbag is generated by the ignition of gas generant within the inflator. Generally, the exhaust gas is created from the rapid burning of pyrotechnic materials. The diffuser serves to control the speed at which the inflator expels the exhaust gas to inflate the airbag. Existing diffusers are fabricated from multiple components that are then welded together. Such diffusers, however, require additional manufacturing steps and introduce excess complexity. Therefore, a need exists for an improved diffuser that overcomes the above- mentioned deficiencies.

SUMMARY

[0005] The present disclosure relates generally to airbag inflation systems for a vehicle, substantially as illustrated by and described in connection with at least one of the figures, as set forth more completely in the claims. More specifically, the present disclosure relates to a diffuser for diffusing inflation gases exiting a curtain airbag inflator in an airbag inflation systems.

DRAWINGS

[0006] The foregoing and other objects, features, and advantages of the devices, systems, and methods described herein will be apparent from the following description of particular examples thereof, as illustrated in the accompanying figures; where like or similar reference numbers refer to like or similar structures. The figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the devices, systems, and methods described herein.

[0007] Figure la illustrates a schematic view of an airbag assembly in accordance with aspects of this disclosure.

[0008] Figure lb illustrates an isometric view of the example diffuser of Figure la.

[0009] Figure 1c illustrates a cross-sectional view of the example diffuser taken along cutline A-A of Figure lb.

[0010] Figure 2a illustrates a side view of the example diffuser of Figures la through 1c.

[0011] Figure 2b illustrates a cross-sectional view taken along cutline A-A of Figure lb.

[0012] Figure 3 illustrates a multi-part diffuser. DESCRIPTION

[0013] References to items in the singular should be understood to include items in the plural, and vice versa, unless explicitly stated otherwise or clear from the text. Grammatical conjunctions are intended to express any and all disjunctive and conjunctive combinations of conjoined clauses, sentences, words, and the like, unless otherwise stated or clear from the context. Recitation of ranges of values herein are not intended to be limiting, referring instead individually to any and all values falling within and/or including the range, unless otherwise indicated herein, and each separate value within such a range is incorporated into the specification as if it were individually recited herein. In the following description, it is understood that terms such as “first,” “second,” “top,” “bottom,” “side,” “front,” “back,” and the like are words of convenience and are not to be construed as limiting terms. For example, while in some examples a first side is located adjacent or near a second side, the terms “first side” and “second side” do not imply any specific order in which the sides are ordered.

[0014] The terms “about,” “approximately,” “substantially,” or the like, when accompanying a numerical value, are to be construed as indicating a deviation as would be appreciated by one of ordinary skill in the art to operate satisfactorily for an intended purpose. Ranges of values and/or numeric values are provided herein as examples only, and do not constitute a limitation on the scope of the disclosure. The use of any and all examples, or exemplary language (“e.g., ” “such as,” or the like) provided herein, is intended merely to better illuminate the disclosed examples and does not pose a limitation on the scope of the disclosure. The terms “e.g.,” and “for example” set off lists of one or more non-limiting examples, instances, or illustrations. No language in the specification should be construed as indicating any unclaimed element as essential to the practice of the disclosed examples.

[0015] The term “and/or” means any one or more of the items in the list joined by “and/or.” As an example, “x and/or y” means any element of the three-element set {(x), (y), (x, y)}. In other words, “x and/or y” means “one or both of x and y”. As another example, “x, y, and/or z” means any element of the seven-element set {(x), (y), (z), (x, y), (x, z), (y, z), (x, y, z)}. In other words, “x, y, and/or z” means “one or more of x, y, and z.”

[0016] A diffuser can be used to control gas exhaust from an inflator into an airbag in an airbag system during an incident. In one example, a diffuser for use in an airbag assembly comprises: a shaft having a first end that is closed and a second end that is open, wherein the shaft includes a first linear portion oriented at an angle (a) relative to a second linear portion, and wherein the first linear portion and the second linear portion are a unitary structure; a fitting positioned at the second end of the shaft, wherein the fitting is configured to couple to an inflator; and at least one exhaust opening formed in the first linear portion, wherein the shaft and the fitting are fluidly coupled to one another to expel exhaust gas from the inflator via the at least one exhaust opening.

[0017] In another example, a rigid metal diffuser for use in an airbag assembly comprises: a shaft having a first end that is closed and a second end that is open, wherein the shaft includes a first linear portion oriented at an angle (a) relative to a second linear portion to gradually redirect the exhaust gas by the angle (a), and wherein the first linear portion and the second linear portion are a unitary structure; a fitting positioned at the second end of the shaft and configured to couple to an inflator, wherein the fitting includes a fitting cavity with an interior surface that is tapered; and a plurality of exhaust openings formed in the first linear portion, wherein the shaft and the fitting are fluidly coupled to one another to expel exhaust gas from the inflator via the plurality of exhaust openings.

[0018] In yet another example, an airbag assembly comprises: an airbag; an inflator positioned within the airbag; and a diffuser coupled to the inflator and configured to control gas exhaust from the inflator, wherein the diffuser comprises a shaft having a first end that is closed and a second end that is open and a fiting positioned at the second end of the shaft and configured to couple to the inflator, wherein the shaft includes a first linear portion having at least one exhaust opening and oriented at an angle (a) relative to a second linear portion, wherein the first linear portion and the second linear portion are a unitary structure, and wherein the shaft and the fitting are fluidly coupled to one another to expel exhaust gas from the inflator via the at least one exhaust opening.

[0019] In some examples, the shaft comprises an angled portion positioned between the first linear portion and the second linear portion, wherein the angled portion is configured to gradually redirect the exhaust gas by the angle (a) from the second linear portion to the first linear portion. In some examples, the at least one exhaust opening is configured to expel exhaust gas from the first linear portion along an output axis that is substantially parallel to an input axis at which the exhaust gas is received at the fitting from the inflator. In some examples, the at least one exhaust opening includes a plurality of exhaust openings. In some examples, the shaft and the fitting are formed via a deep drawing metal forming process. In some examples, the fitting defines a fitting cavity with an interior surface that is tapered. In some examples, the first linear portion defines the first end and the at least one exhaust opening is positioned adjacent the first end. In some examples, the diffuser is fabricated using a rigid metal.

[0020] Figure 1 a illustrates a schematic view of an airbag assembly 100. Airbag technology has advanced to place airbag assemblies 100 throughout vehicles that protect occupants during a front impact, side impact, roll-over accident, etc. Airbag assemblies 100 designed to address side impact and roll-over accident use airbags that are generally known as curtain airbags 106. Generally, the curtain airbag 106 inflates and descends from a frame member of the vehicle to cover a majority of the area between the occupant and the side of the vehicle interior. The inflated curtain airbag 106 appears much like a curtain covering the vehicle window. The curtain airbag 106 is typically attached to a thin long frame member that runs along a side of the roof of the vehicle. Due to physical constraints, such as window size and visibility requirements, the curtain-style airbag assembly 100 are often a long thin shape.

[0021] An electronic control unit (ECU) 108 is often used to control the various airbag assemblies 100 in a vehicle. While only a single airbag assembly 100 is illustrated, the ECU 108 is often coupled to and configure to control multiple airbag assemblies 100. The ECU 108 typically includes or is communicatively coupled with a processor and one or more sensors that continuously monitor operation of the vehicle to determine whether the vehicle is in an accident situation. When the ECU 108, via the processor, determines that there is an accident situation, the ECU 108 transmits an electrical current to an initiator 107 in the airbag assembly 100. The initiator 107 triggers operation of the inflator 104.

[0022] The inflator 104 ignites a gas generant within the inflator 104 to generate exhaust gas that fills the curtain airbag 106. The inflator 104 can use a combination of compressed gas and solid fuel to generate gas to inflate the curtain airbag 106 quickly. That is, the inflator 104 inflates the curtain airbag 106 that cushions a passenger during impacts to prevent injury to the passenger. The curtain airbag 106 can be fabricated from a textile material, such as a nylon or polyester weave. In some cases, the curtain airbag 106 may be fully inflated within 50 thousandths of a second and deflated within two tenths of a second. In this manner, the inflator 104 is capable of providing sufficient inflation gas to properly inflate the curtain airbag 106. Because the airbag assembly 100 (with the un-inflated curtain airbag 106) is installed in a very limited thin space defined by the roof frame member, the inflator 104 is also typically shaped as a thin, cylindrical member that extends a portion of the length of the curtain airbag 106.

[0023] Due to the limited space, the curtain airbag 106 is generally stored by folding the curtain airbag 106 relative to the inflator 104. In many applications, the inflator 104 is installed within the curtain airbag 106; however, doing so generally requires that the inflator 104 include a diffuser 102 to control gas exhaust during an incident. Generally, the inflator 104 creates exhaust gas from the rapid burning of pyrotechnic materials. The exhaust gas escapes exit ports in the inflator 104 at a high velocity and temperature. Without a diffuser 102, the exhaust gas would be directed and concentrated on the material of the curtain airbag 106. The concentrated hot exhaust gas and the confined space can combine to cause the exhaust gas to bum one or more holes in the material of the curtain airbag 106. The holes may cause the curtain airbag 106 to inflate improperly. The diffuser 102, however, mitigates this risk.

[0024] Figure lb illustrates an isometric view of an example diffuser 102, while Figure 1c illustrates a cross-sectional view taken along cutline A- A. The diffuser 102 generally comprises a shaft 112 and a fitting 110. The fiting 110 is configured to engage or otherwise atach to the exit port(s) of the inflator 104. In the illustrated example, the fiting 110 is sized to receive an end of the inflator 104; however, it is contemplated that the fiting 110 could threadedly engage the inflator 104 or use another atachment means. In some examples, additionally or alternatively, the fiting 110 can be welded or otherwise adhered to the inflator 104.

[0025] In the illustrated example, the shaft 112 of the diffuser 102 is closed at a first end 116a and coupled to the fiting 110 at a second end 116b. The second end 116b is open to receive exhaust gas from the inflator 104 via an opening in the fiting 110. The shaft 112 further comprises one or more exhaust openings 114 along the outer side of the shaft 112 to expel exhaust gas into the curtain airbag 106. The one or more exhaust openings 114 are positioned adjacent or near the first end 116a (i.e., the closed end). The size and quantity of the one or more exhaust openings 114 are dictated by flow rate requirements for a particular application. For example, the flow rate requirements would depend on the size (e g., internal volume) and/or shape of the curtain airbag 106.

[0026] Figure 2a illustrates a side view of the example diffuser 102 of Figures la through

1c, while Figure 2b illustrates a cross-sectional view taken along cutline A-A. Figures 2c and

2d illustrate, respectively, top plan and elevational rear views of the example diffuser 102. The diffuser 102 is used to, inter alia, direct the exhaust gas leaving the exit port(s) of the inflator 104. More specifically, the diffuser 102 serves to disperse the exhaust gas to allow the exhaust gas to expand and cool. The surface of the diffuser 102 further allows the exhaust gas 202 to transfer some of its heat, effectively functioning as a heat exchanger. Once the exhaust gas passes through a diffuser 102, the exhaust gas is sufficiently cooled and/or not concentrated to prevent burning holes in the curtain airbag 106.

[0027] As best illustrated in Figure 2a, the shaft 112 generally comprises a first linear portion 112a, a second linear portion 112b, and an angled portion 112c therebetween. As illustrated, the distal end of the first linear portion 112a is closed (i.e., at the first end 116a) and the fitting 110 is located at the proximal end of the second linear portion 112b (i.e., at the second end 116b).

[0028] The angled portion 112c is configured to orient a first central axis 118a of the first linear portion 112a at an angle (a) relative to a second central axis 118b of the second linear portion 112b. With reference to Figure 2b, exhaust gas 202 from the inflator 104 is guided through the second linear portion 112b along the second central axis 118b, then redirected by about 90 degrees by the angled portion 112c such that the exhaust gas 202 is guided through the first linear portion 112a along the first central axis 118a. The exhaust gas 202 is then pushed outside the first linear portion 112a via the one or more exhaust openings 114. As illustrated, the direction of travel of the exhaust gas 202 exiting the diffuser 102 is parallel the direction of travel of the exhaust gas 202 entering the diffuser 102. In other words, the exhaust opening(s) 114 are configured to expel exhaust gas 202 from the first linear portion 112a along an output axis 210 that is substantially parallel to an input axis 208 at which the received the exhaust gas 202 at the fitting 110 from the inflator 104.

[0029] The angle (a) is illustrated as 90 degrees, but other angles (a) are contemplated. For example, the angle (a) may be between about 30 and 120 degrees, between about 45 and 135 degrees, or between about 85 and 95 degrees. As can be appreciated, unlike a two-piece variation that will be described in connection with Figure 3, the interior walls of the angled portion 112c are shaped to gradually redirect the exhaust gas 202 to make the 90 degree turn, thus mitigating potential turbulence at the turn. In some examples, the exhaust gas 202 may be directed through an exhaust passage to allow the exhaust gas to further cool before entering the curtain airbag 106. Conventionally, exhaust passages are structures formed between the inflator 104 and the diffuser 102.

[0030] In some examples, the diffuser 102 is configured to cause the curtain airbag 106 to inflate in a particular manner. For example, the one or more exhaust openings 114 may be distributed or otherwise positioned in a manner to direct more exhaust gas 202 to one area over another area, thereby causing one or more portions of the curtain airbag 106 to inflate at different rates (e.g., more quickly or slowly) than others. In some examples, the exhaust openings 114 may be distributed along the entire length of the first linear portion 112a and/or the second linear portion 112b. Additionally or alternatively, one or more exhaust openings 114 may positioned on the angled portion 112c.

[0031] Providing the diffuser 102 as a component that is separate from the inflator 104 allows for a standard inflator 104 to be used with various differently-shaped diffusers. That is, different vehicles and/or locations within a vehicle may warrant different diffuser shapes. Nevertheless, while described as a separate component, in some examples, the disclosed diffuser 102 could be integrated with the body of the inflator 104; however, doing would increase the production and design costs of the inflator 104. For example, when a diffuser 102 is incorporated into the body of the inflator 104, custom fabrication of inflator 104 bodies may be required to provide diffuser 102 features for different vehicles. Additionally, combination with anon-standard inflator 104 or diffuser 102 may increase training time required for workers assembling the airbag assembly 100. [0032] To account for non-standard inflators 104, such as those having differently shaped or sized exit ports, the fitting 110 may be sized and shaped to accommodate inflators 104 with differently sized of shaped exit ports. For example, the interior surface 206 of the fitting cavity 204 of the fitting 110 may be tapered to increase tolerances between the diffuser 102 and inflators 104 having different diameters. That is, inflators 104 with smaller exit ports would be inserted deeper into the fitting cavity 204 prior to welding (or otherwise), whereas inflators 104 with larger exit ports would be more shallowly inserted into the fitting cavity 204 prior to welding (or otherwise).

[0033] The diffuser 102 is preferably fabricated using a rigid metal, such as steel, stainless steel, aluminum, copper, or the like. Alternatively, the diffuser 102 maybe made from a phenolic resin based material. While the diffuser 102 is described as having multiple portions (e.g., the first linear portion 112a, second linear portion 112b, angled portion 112c, and/or fitting 110), the diffuser 102 can be fabricated as a unitary structure using, for example, a deep drawing metal forming process. To that end, the shaft 112 and the fitting 110 (where desired) can be fabricated a single unitary structure, rather than as separate components that are later joined together.

[0034] In one method of manufacture, a blank is used to fabricate the diffuser 102. The blank may be a piece of about 24 to about 26 gauge steel, for example. Alternatively, other gauges and kinds of materials, both metallic and non-metallic may be used including copper, aluminum, compositions including phenolic resins, and the like. Preferably, the material for the blank is pliable. The one or more exhaust openings 114 are formed in the blank via, for example, a stamping or deep drawn operation. The formed blank can then be shaped to form a unitary diffuser 102 via a combination of deep drawing metal forming process and a bending operation either inside or outside of the deep draw n stamping tooling [0035] Figure 3 illustrates a multi-part diffuser 300. As illustrated, the multi-part diffuser 300 comprises a first linear part 302 joined to a second linear part 304 at a right angle, which is indicated angle (P) in Figure 3. Specifically, the first linear part 302 is inserted into an opening 306 formed in the sidewall of the second linear part 304. The multi-part diffuser 300 operates similarly to diffuser 102 in that exhaust gas 202 enters the second linear part 304 and is directed to the first linear part 302 prior to exiting the first linear part 302, however the multipart diffuser 300 presents certain disadvantages. First, the multi-part diffuser 300 requires multiple manufacturing steps as the first linear part 302 and the second linear part 304 must be manufactured and later joined (e.g., welded). The opening 306 formed would also have to be formed in the second linear part 304 prior to assembly. These additional steps result in increased manufacturing cost and manufacturing time. Second, the angle ( ) would be limited to about 90 degrees because the shape and thickness of the second linear part 304 at the opening 306 restrict the use of other angles (P) without introducing additional manufacturing steps. Finally, the interior walls of the multi-part diffuser 300 at the connection point does not gradually redirect the exhaust gas 202 when making the 90 degree turn, thus potentially increasing turbulence at the turn Such turbulence could affect flow rate, for example.

[0036] The above-cited patents and patent publications are hereby incorporated by reference in their entirety. Where a definition or the usage of a term in a reference that is incorporated by reference herein is inconsistent or contrary to the definition or understanding of that term as provided herein, the meaning of the term provided herein governs and the definition of that term in the reference does not necessarily apply.

[0037] While the present method and/or system has been described with reference to certain implementations, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the scope of the present method and/or system. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the present disclosure without departing from its scope. For example, block and/or components of disclosed examples may be combined, divided, re-arranged, and/or otherwise modified. Therefore, the present method and/or system are not limited to the particular implementations disclosed. Instead, the present method and/or system will include all implementations falling within the scope of the appended claims, both literally and under the doctrine of equivalents.

Claims

1. A diffuser for use in an airbag assembly, the diffuser comprising: a shaft having a first end that is closed and a second end that is open, wherein the shaft includes a first linear portion oriented at an angle (a) relative to a second linear portion, and wherein the first linear portion and the second linear portion are a unitary structure; a fitting positioned at the second end of the shaft, wherein the fitting is configured to couple to an inflator; and at least one exhaust opening formed in the first linear portion, wherein the shaft and the fitting are fluidly coupled to one another to expel exhaust gas from the inflator via the at least one exhaust opening.

2. The diffuser of claim 1, wherein the shaft comprises an angled portion positioned between the first linear portion and the second linear portion, wherein the angled portion is configured to gradually redirect the exhaust gas by the angle (a) from the second linear portion to the first linear portion.

3. The diffuser of claim 1, wherein the at least one exhaust opening is configured to expel exhaust gas from the first linear portion along an output axis that is substantially parallel to an input axis at which the exhaust gas is received at the fitting from the inflator.

4. The diffuser of claim 1, wherein the at least one exhaust opening includes a plurality of exhaust openings.

5. The diffuser of claim 1, wherein the shaft and the fitting are formed via a deep drawing metal forming process.

6. The diffuser of claim 1, wherein the fitting defines a fitting cavity with an interior surface that is tapered.

7. The diffuser of claim 1, wherein the first linear portion defines the first end and the at least one exhaust opening is positioned adjacent the first end.

8. The diffuser of claim 1, wherein the diffuser is fabricated using a rigid metal.

9. A rigid metal diffuser for use in an airbag assembly, the rigid metal diffuser comprising: a shaft having a first end that is closed and a second end that is open, wherein the shaft includes a first linear portion oriented at an angle (a) relative to a second linear portion to gradually redirect the exhaust gas by the angle (a), and wherein the first linear portion and the second linear portion are a unitary structure; a fitting positioned at the second end of the shaft and configured to couple to an inflator, wherein the fitting includes a fitting cavity with an interior surface that is tapered; and a plurality of exhaust openings formed in the first linear portion, wherein the shaft and the fitting are fluidly coupled to one another to expel exhaust gas from the inflator via the plurality of exhaust openings.

10. The rigid metal diffuser of claim 9, wherein the plurality of exhaust openings is configured to expel exhaust gas from the first linear portion along an output axis that is substantially parallel to an input axis at which the exhaust gas is received at the fitting from the inflator.

11. An airbag assembly comprising: an airbag, an inflator positioned within the airbag; and a diffuser coupled to the inflator and configured to control gas exhaust from the inflator, wherein the diffuser comprises a shaft having a first end that is closed and a second end that is open and a fitting positioned at the second end of the shaft and configured to couple to the inflator, wherein the shaft includes a first linear portion having at least one exhaust opening and oriented at an angle (a) relative to a second linear portion, wherein the first linear portion and the second linear portion are a unitary structure, and wherein the shaft and the fitting are fluidly coupled to one another to expel exhaust gas from the inflator via the at least one exhaust opening.

12. The airbag assembly of claim 11, wherein the shaft comprises an angled portion positioned between the first linear portion and the second linear portion, wherein the angled portion is configured to gradually redirect exhaust gas by the angle (a) from the second linear portion to the first linear portion.

13. The airbag assembly of claim 11, wherein the at least one exhaust opening is configured to expel exhaust gas from the first linear portion along an output axis that is substantially parallel to an input axis at which exhaust gas is received at the fitting from the inflator.

14. The airbag assembly of claim 11, wherein the at least one exhaust opening includes a plurality of exhaust openings.

15. The airbag assembly of claim 11, wherein the shaft and the fitting are formed via a deep drawing metal forming process.

16. The airbag assembly of claim 11 , wherein the fitting defines a fitting cavity with an interior surface that is tapered.

17. The airbag assembly of claim 11 , wherein the first linear portion defines the first end and the at least one exhaust opening is positioned adjacent the first end.

18. The airbag assembly of claim 11 , wherein the diffuser is fabricated using a rigid metal.