Conductive actuator housing and related airbag assembly

Abstract

Actuator housing for an airbag module and related assemblies. The airbag assembly includes a conductive component and an electric explosive device (110) coupled to and positioned adjacent to the conductive component. The assembly further includes a housing (120) for the electric explosive device (110). The housing is at least partially defined by a conductive plastic material having a conductivity lower than that of the conductive component.

Description

Technical Field

[0001] Electrostatic discharge is often a problem that requires mitigation in vehicle safety systems having explosive devices such as tether release actuators. Such explosive devices are often housed within non-conductive plastics, which can result in the accumulation of unwanted frictional charges and the potential for sudden electrostatic discharge and / or premature ignition. Mitigating such results may require large-scale and / or expensive components for controlling the accumulation of frictional charges, such as ground wires, metal cases, connector sockets, and / or shorting clips for ground connections.

[0002] Accordingly, the inventors have determined that it would be desirable to provide an apparatus, system, and method that overcomes one or more of the foregoing limitations and / or other limitations of the prior art. Accordingly, in some embodiments, the inventive concepts disclosed herein can control the accumulation of frictional charges, eliminate or at least significantly reduce the risk of premature ignition, and / or reduce the breakdown voltage associated with the explosive device, housing, and / or associated modules by replacing the insulating material of the explosive device / actuator housing with a relatively conductive material such as conductive plastic in a preferred embodiment.

[0003] In a more specific example of an airbag assembly according to some embodiments, the airbag assembly can include a conductive component and an explosive device coupled to and positioned adjacent to the conductive component. The assembly may further include a housing for the explosive device, which may be at least partially defined by a conductive plastic material having a conductivity lower than that of the conductive component.

[0004] In some embodiments, the explosive device may be configured to release a tether.

[0005] In some embodiments, the housing may be entirely defined by a conductive plastic material. Alternatively, the housing may be only partially defined by a conductive plastic material. For example, the housing may include a component or section that defines a complete path between a portion of the housing that defines a spark gap associated with the electrical explosion device and a higher conductive and / or metallic portion of the assembly.

[0006] In some embodiments, the conductive component may include a plate, such as a backer plate of an inflator module.

[0007] In some embodiments, the conductive component may include a metal component.

[0008] In some embodiments, the housing may be configured to receive an electrical explosion device so as to maintain a spark gap between a portion of the electrical explosion device and the housing. In some such embodiments, the spark gap may be configured with a consistent distance, minimum distance, and / or average distance of from about 0.3 mm to about 1.5 mm. In some embodiments, the portion of the electrical explosion device that defines the spark gap may include an initiator cup.

[0009] In a particular example of an actuator module for an airbag assembly, the actuator module may include an electric explosion device that includes an initiator cup. The actuator module may further include a housing for the electric explosion device, the housing being configured to receive the electric explosion device so as to maintain a spark gap between the initiator cup and the housing. At least a portion of the housing that defines the spark gap can include a conductive plastic material. In some embodiments, the housing may be entirely defined by the conductive plastic material. The actuator module may further include a metal portion. The conductive plastic material can extend from at least a portion of the housing that defines the spark gap to the metal portion.

[0010] In some embodiments, the conductive plastic material can have a lower conductivity than the metal portion.

[0011] In some embodiments, the electric explosion device may be configured to release an airbag cushion tether.

[0012] In some embodiments, the metal portion can include a metal plate such as a backer plate for an inflation module. In some such embodiments, the metal plate may be part of the module body of the actuator module. In some such embodiments, the housing may be configured to reduce the breakdown voltage associated with the module body.

[0013] In certain example embodiments of a tether release actuator assembly, the assembly may include an electro-explosive device configured to release a tether upon actuation, a body at least partially defined by a first material having a first conductivity, and a housing coupled to the body. The housing may be configured to receive the electro-explosive device therein and may include, optionally fully, a second non-insulating material having a second conductivity lower than the first conductivity.

[0014] In some embodiments, the housing may be configured to discharge a triboelectric charge from the electro-explosive device.

[0015] In some embodiments, the housing may be configured to reduce the breakdown voltage of the body.

[0016] In some embodiments, the first material may include a metal and / or the second material may include a conductive plastic. In some such embodiments, the conductive plastic may include a polyamide material modified to increase conductivity.

[0017] In some embodiments, features, structures, acts, or characteristics disclosed herein in connection with one embodiment may be combined in any suitable manner in one or more alternative embodiments.

Brief Description of the Drawings

[0018] With reference to the drawings, non-limiting and non-exhaustive embodiments of the present disclosure, including various embodiments thereof, are described.

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[0019] A detailed description of devices, systems, and methods consistent with various embodiments of the present disclosure is provided below. Although some embodiments are described, it should be understood that the present disclosure is not limited to any of the specific embodiments disclosed, but instead includes numerous alternative forms, modifications, and equivalents. Additionally, numerous specific details are set forth in the following description to provide a complete understanding of the embodiments disclosed herein, but some embodiments can be practiced without some or all of these details. Further, specific technical materials known in the relevant technical field are not described in detail to avoid unnecessarily obscuring the present disclosure for clarity purposes.

[0020] As used herein, the term "substantially" refers to a complete or nearly complete degree or extent of an operation, characteristic, attribute, state, structure, item, or result that functions as indicated. For example, an object that is "substantially" cylindrical or "substantially" vertical means that the object / feature is either cylindrical / vertical or nearly cylindrical / vertical such that it provides the same or nearly the same function. The exact allowable degree of deviation provided by this term may depend on the specific context. The use of "substantially" is equally applicable when used in a negative sense to refer to a complete or nearly complete absence of an operation, characteristic, attribute, state, structure, item, or result. For example, a structure that is "substantially free of" a bottom means that it either completely lacks a bottom or lacks a bottom to such an extent that its effect is substantially the same as if it completely lacked a bottom.

[0021] Similarly, as used herein, the term "about" is used to provide flexibility to the endpoints of a numerical range by providing that a given value can be "slightly above" or "slightly below" the endpoints while still achieving the associated function for the range.

[0022] Embodiments of the present disclosure may be best understood by reference to the drawings, wherein like parts may be designated by like numerals. It will be readily understood that the components of the disclosed embodiments, as generally described and illustrated in the figures herein, may be arranged and designed in a wide variety of different configurations. Accordingly, the following detailed description of the embodiments of the apparatus and method of the present disclosure is not intended to limit the scope of the present disclosure as claimed, but is merely representative of possible embodiments of the present disclosure. In addition, unless otherwise specified, the steps of the methods need not be performed in any particular order, or even sequentially, nor do the steps need to be performed only once. Further details regarding specific preferred embodiments and implementations will be described in more detail herein with reference to the accompanying drawings.

[0023] Figures 1 and 2 show an inflator module 100 for an airbag assembly according to some embodiments. The module 100 includes an inflator body 102, and the inflator body 110 can function as a common ground for a tether release actuator 110 as described below. The module 100 further includes a backer plate 105 that is electrically grounded to the inflator body 102. An actuator housing 120, configured to receive the tether release actuator 110, is coupled to the backer plate 105 of the module 100 by one or more fasteners 104. Figure 1 shows the tether release actuator 110 disassembled from its seat within the actuator housing 120, and Figure 2 shows the tether release actuator 110 seated within the actuator housing 120.

[0024] Preferably, the actuator housing 120, or in some contemplated embodiments at least a portion of the actuator housing 120, comprises a material having a conductivity greater than that of the insulating plastic materials often used for such housings. However, in some such preferred embodiments, this material can have a conductivity lower than that of the conductive (typically metallic) elements providing the electrical path to ground, thereby allowing the triboelectric charge to be discharged from the module 100. In a preferred embodiment, this material can include a conductive plastic material, such as a polyamide material modified to increase its conductivity. In a more specific example of a material suitable for this purpose, the material can include reinforced polyamide 6 sold under the trade name K224 - PGC62 by Akulon®.

[0025] FIG. 2 further shows the presence of the tether 112 along a portion of the actuator 110, and the tether 210 may be coupled to associated components of the airbag cushion, such as an airbag cushion or a vent opening, as will be understood by those skilled in the art. Thus, the actuator 110 may be used to release the tether 112 during actuation to effect one or more aspects of the deployment characteristics of the airbag cushion. However, it should be understood that other embodiments where the actuator 110 can be used for other purposes, such as a seatbelt pretensioner, or any other application where the use of an insulating plastic for the actuator housing results in an undesirable accumulation of triboelectric charge, are contemplated.

[0026] FIG. 3 is a cross - sectional view through the actuator 110 and its actuator housing 120. As shown in this figure, the actuator 110 may be in proximity to and / or in contact with one or more regions of the semiconductive housing 120, thereby potentially allowing the safe discharge of triboelectric charge to the conductive and / or metallic regions of the module 100, and thereby potentially allowing such charge to ultimately be delivered to ground.

[0027] Figure 4 is an enlarged view of the cross-section of Figure 3. As shown in this figure, in certain preferred embodiments, the spark gap G can be present between a portion of the actuator 110 and at least a portion of the housing 120. More specifically, in the illustrated embodiment, the spark gap G is positioned between the initiator cup 114 and an adjacent portion of the housing 120. Maintaining a relatively small air / spark gap G can preferably be combined with using another material having conductivity between a conductive plastic material, or a fully conductive material such as metal, and an insulating material such as insulating plastic, to substantially reduce the breakdown voltage associated with the actuator 110, the housing 120, and / or the module 100.

[0028] For example, the inventors have discovered that, as disclosed herein, by replacing a typical insulating plastic for the housing 120 with a conductive plastic, the breakdown voltage can be reduced from about 23 to about 26 kV to about 2 to about 5 kV. This can enable the breakdown voltage to be controlled by design control. Thus, it may be desirable to design the module / system such that the breakdown voltage is lower than the initiator electrostatic discharge (ESD) non-fire-resistant level, and in some cases, significantly lower. In other words, configuring the breakdown voltage to be lower than the ESD non-fire-resistant level can be used to eliminate or at least substantially reduce the possibility of the frictional charge accumulating to a dangerous level that can trigger the initiator of the electroexplosive device.

[0029] In some embodiments, the spark gap G may include a distance measured at several points along the gap (in some cases, a consistent distance and / or an average distance, or at least substantially a consistent distance and / or an average distance), and in other cases, may include a minimum distance of about 0.3 mm to about 1.5 mm between the initiator cup or another relevant portion of the actuator and the associated housing.

[0030] As described above, it may be easier to construct the entire housing 120 from a conductive material or a material that is relatively conductive (compared to the fully conductive regions and / or metal regions of the module 100) rather than from an insulating material. However, it is contemplated that some embodiments may be configured to be constructed only partially, rather than completely, from such materials. For example, in some embodiments, the portion of the housing 120 that defines the spark gap G can include the relatively conductive material / semiconductive material described above. Preferably, the housing 120 is constructed such that this material extends at least in a continuous form up to a metal / fully conductive component such as the metal portion of the module 100 or up to the portion of the vehicle chassis to which the module 100 and / or the housing 120 is attached.

[0031] Thus, in the context of the embodiments shown in the drawings, for example, instead of forming the entire housing 120 from a relatively conductive material / semiconductive material, the protrusion 122 that extends into the initiator cup 114 and defines the spark gap G may be formed from this conductive plastic or another relatively conductive material. This material may then extend along one or more paths, preferably continuously, for example, preferably to one or more fasteners 104 or other elements that contact the backplate 105 and / or another metal portion of the module 100.

[0032] The foregoing specification has been described with reference to various embodiments and implementations. However, those skilled in the art will understand that various modifications and changes can be made without departing from the scope of the present disclosure. For example, the various operational steps, as well as the components for performing the operational steps, can be implemented in various ways depending on a particular application or in consideration of any number of cost functions associated with the operation of the system. Accordingly, any one or more of the steps can be deleted, modified, or combined with other steps. Further, the present disclosure should be regarded as illustrative rather than limiting in nature, and all such modifications are intended to be included within the scope of the present disclosure. Similarly, with respect to the various embodiments, benefits, other advantages, and solutions to problems have been described above. However, benefits, advantages, solutions to problems, and any element that can give rise to or make more prominent any benefit, advantage, or solution should not be construed as an important, necessary, or essential feature or element.

[0033] Those skilled in the art will understand that many changes can be made to the details of the embodiments described above without departing from the basic principles of the invention. Accordingly, the scope of the invention should be determined solely by the following claims.

Claims

**Claim 1** An airbag assembly comprising a conductive component, an electric explosion device [110] coupled to the conductive component and positioned adjacent to the conductive component, and a housing [120] for the electric explosion device [110], wherein the housing [120] is at least partially defined by a conductive plastic material having a conductivity lower than that of the conductive component. The airbag assembly is characterized by this. **Claim 2** The airbag assembly according to claim 1, wherein the electric explosion device [110] is configured to release a tether [112]. **Claim 3** The airbag assembly according to claim 1 or 2, wherein the housing (120) is entirely defined by the conductive plastic material. **Claim 4** The airbag assembly according to any one of claims 1 to 3, wherein the conductive component includes a metal component. **Claim 5** The airbag assembly according to any one of claims 1 to 4, wherein the housing [120] is configured to receive the electric explosion device [110] so as to maintain a spark gap between a part of the electric explosion device [110] and the housing [120]. **Claim 6** The airbag assembly according to claim 5, wherein the part of the electric explosion device [110] includes an initiator cup [114]. **Claim 7** The airbag assembly according to any one of claims 1 to 6, wherein the conductive component includes a metal plate [105]. **Claim 8** The airbag assembly according to claim 7, wherein the metal plate (105) is part of a module body of an actuator module. **Claim 9** The airbag assembly according to claim 8, wherein the housing [120] is configured to reduce a breakdown voltage associated with the module body. **Claim 10** The airbag assembly according to any one of claims 1 to 9, wherein the housing [120] is configured to discharge frictional charges from the electric explosion device [110]. **Claim 11** The airbag assembly according to any one of claims 1 to 10, wherein the conductive plastic includes a polyamide material modified to increase conductivity.

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