Conductive actuator housing and associated 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, and as a result, undesirable frictional charges can accumulate, potentially causing 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] Therefore, the inventors have determined that it would be desirable to provide an apparatus, system, and method that overcome one or more of the foregoing limitations and / or other limitations of the prior art. Thus, in some embodiments, the inventive concept 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 an explosive device, housing, and / or associated module by replacing the insulating material of the explosive device / actuator housing with a relatively conductive material such as a 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 partially defined by a conductive plastic material. For example, the housing may include a portion of the housing that defines a spark gap associated with the electric explosive device and a part or section that defines a complete path between the more 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 the electric explosive device so as to maintain a spark gap between a portion of the electric explosive device and the housing. In some such embodiments, the spark gap may consist of a consistent distance, a minimum distance, and / or an average distance of about 0.3 mm to about 1.5 mm. In some embodiments, the portion of the electric explosive device defining 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 explosive device, including an initiator cup. The actuator module may further include a housing for the electric explosive device, the housing being configured to receive the electric explosive device so as to maintain a spark gap between the initiator cup and the housing. At least a portion of the housing defining the spark gap may 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 may extend from at least a portion of the housing defining the spark gap to the metal portion.

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

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

[0012] In some embodiments, the metal portion may include a metal plate, such as a backer plate for the 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 breakover voltage associated with the module body.

[0013] In certain examples of tether release actuator assemblies according to several embodiments, the assembly may include an electric explosive device configured to release a tether when actuated, 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 electric explosive device therein and may include, and possibly entirely include, 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 frictional charge from the electric explosion device.

[0015] In some embodiments, the housing may be configured to reduce the breakover voltage of the main 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, processes, or properties disclosed herein in relation to one embodiment may be combined in any preferred manner in one or more alternative embodiments. [Brief explanation of the drawing]

[0018] With reference to the drawings, non-limiting and non-exclusive embodiments of the present disclosure, including various embodiments thereof, will be described. [Figure 1] Figure 1 shows a perspective view of an airbag module assembly including a tether release actuator according to several embodiments. [Figure 2] Figure 2 shows the airbag module assembly from Figure 1, with the tether release actuator positioned within the conductive actuator housing of the airbag module assembly. [Figure 3] Figure 3 is a cross-sectional view along line 3-3 in Figure 2. [Figure 4] Figure 4 is an enlarged view of the cross-section shown in Figure 3. [Modes for carrying out the invention]

[0019] A detailed description of apparatus, systems, and methods consistent with various embodiments of this disclosure is provided below. While several embodiments are described, it should be understood that this disclosure is not limited to any particular embodiment disclosed, but rather encompasses a number of alternative forms, modifications, and equivalents. In addition, while many specific details are given in the following description to provide a complete understanding of the embodiments disclosed herein, some embodiments can be carried out without some or all of these details. Furthermore, for the purpose of clarity and to avoid unnecessarily obscuring this disclosure, certain technical documents known in the relevant art are not described in detail.

[0020] As used herein, the term “substantially” refers to the complete or near-complete degree or extent of an action, 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 / characteristic is either cylindrical / vertical or nearly cylindrical / vertical to produce the same or nearly the same function. The exact degree of permissible deviation provided by this term may depend on the specific context. The use of “substantially” is equally applicable when used in a negative implication to refer to the complete or near-complete absence of an action, characteristic, attribute, state, structure, item, or result. For example, a structure that “substantially” lacks a bottom either completely lacks a bottom or nearly completely lacks a bottom to produce substantially the same effect as if the bottom were completely lacking.

[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 “just above” or “just below” an endpoint while still achieving the function associated with the range.

[0022] Embodiments of the disclosed invention can be best understood by reference to the drawings, and similar parts may be designated by similar numbers. It will be readily apparent that the components of the disclosed embodiments can be arranged and designed in a wide variety of different configurations, as generally described and illustrated in the drawings herein. Accordingly, the following detailed description of embodiments of the apparatus and methods of the disclosed invention is not intended to limit the scope of the disclosure as claimed, but merely to represent possible embodiments of the disclosure. In addition, unless otherwise specified, the steps of the method do not necessarily have to be performed in any particular order, or even sequentially, and the steps do not have to be performed only once. Further details regarding specific preferred embodiments and implementations are described herein in more detail with reference to the accompanying drawings.

[0023] Figures 1 and 2 show inflator modules 100 for airbag assemblies according to several embodiments. Module 100 includes an inflator body 102, and an inflator body 110 can function as a common ground for the tether release actuator 110, as described below. Module 100 further includes a backer plate 105 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 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, includes 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 that provide an electrical path to ground, thereby allowing triboelectric charges to be discharged from the module 100. In a preferred embodiment, this material can include a conductive plastic material, such as, for example, a polyamide material modified to increase 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] Figure 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 operation to effect one or more aspects of the deployment characteristics of the airbag cushion. However, it should be understood that other embodiments in which the actuator 110 may 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] Figure 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 proximate to and / or in contact with one or more regions of the semiconductive housing 120, thereby potentially allowing triboelectric charges to be safely discharged to the conductive regions and / or metallic regions of the module 100, and thereby potentially allowing such charges to ultimately be delivered to ground.

[0027] Figure 4 is an enlarged view of the cross-section of FIG. 3. As shown in this figure, in certain preferred embodiments, the spark gap G may 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 may 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 may 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 an 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 mentioned above, it may be easier to construct the entire housing 120 from a conductive material or a relatively conductive material (compared to the fully conductive and / or metallic regions of module 100) rather than from an insulating material, but some embodiments are intended to be configured to be constructed only partially, and not entirely, from such materials. For example, in some embodiments, the portion of the housing 120 defining the spark gap G may include the aforementioned relatively conductive / semiconductive material. Preferably, the housing 120 is constructed such that this material extends at least in a continuous manner to a metallic / fully conductive component such as the metallic portion of module 100, or to the portion of the vehicle chassis to which module 100 and / or housing 120 is mounted.

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

[0032] The aforementioned 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 this disclosure. For example, various operating processes and components for performing those processes can be implemented in various ways depending on the particular application or taking into account any number of cost functions associated with the operation of the system. Thus, any one or more of the processes can be deleted, modified, or combined with other processes. Furthermore, this disclosure should be considered illustrative rather than restrictive, and all such modifications are intended to be within the scope of this disclosure. Similarly, with respect to various embodiments, benefits, other advantages, and solutions to problems have been described above. However, benefits, advantages, solutions to problems, and any elements that can produce or make more prominent any benefits, advantages, or solutions should not be construed as important, necessary, or essential features or elements.

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

Claims

1. An airbag assembly comprising a conductive component, an electric explosive device [110] coupled to the conductive component and positioned adjacent to the conductive component, and a housing [120] for the electric explosive 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, and the housing [120] is configured to receive the electric explosive device [110] such that a spark gap is maintained between a portion of the electric explosive device [110] and the housing [120].

2. The airbag assembly according to claim 1, wherein the electric explosion device [110] is configured to release the tether [112].

3. The airbag assembly according to claim 1, wherein the housing (120) is defined as a whole by the conductive plastic material.

4. The airbag assembly according to claim 1, wherein the conductive component includes a metal component.

5. The airbag assembly according to claim 1, wherein the portion of the electric explosion device [110] includes an initiator cup [114].

6. An airbag assembly comprising a conductive component, an electric explosive device [110] coupled to the conductive component and positioned adjacent to the conductive component, and a housing [120] for the electric explosive 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 conductive component is an airbag assembly including a metal plate [105].

7. The airbag assembly according to claim 6, wherein the metal plate (105) is part of the module body of the actuator module.

8. The airbag assembly according to claim 7, wherein the housing [120] is configured to reduce the breakover voltage associated with the module body.

9. The airbag assembly according to claim 1, wherein the housing [120] is configured to discharge frictional charge from the electric explosion device [110].

10. The airbag assembly according to claim 1, wherein the conductive plastic comprises a polyamide material modified to increase conductivity.

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