Patent Publication Number: US-2012025503-A1

Title: Unitary diffusers for use with air bag cushion inflators

Description:
TECHNICAL FIELD 
     The present disclosure relates generally to inflatable air bag cushions for motor vehicles. More specifically, various embodiments of the present disclosure relate to devices, systems and methods used in inflatable air bag cushions for motor vehicles. 
     BACKGROUND 
     Modern motor vehicles typically employ various occupant protection systems that self-actuate from an undeployed to a deployed state without the need for intervention by the occupant. Such systems often include an inflatable occupant protection system in the form of a cushion or bag, commonly referred to as an “air bag cushion.” Such air bag cushions may deploy into one or more locations within the vehicle between the occupant and certain parts of the vehicle interior, such as the doors, steering wheel, instrument panel, dashboard or the like, to prevent or cushion the occupant from forcibly striking such parts of the vehicle interior. 
     Various types or forms of occupant protection systems have been developed or tailored to provide desired vehicle occupant protection based on either or both the position or placement of the occupant within the vehicle and the direction or nature of the vehicle collision. For example, driver and passenger inflatable cushion installations have found wide usage for providing protection to drivers and front seat passengers, respectively, in the event of head-on type of collision. Other installations have found wide usage for providing protection to vehicle occupants in the event of a side impact (e.g., side collision, roll-over). 
     The air bag cushion is conventionally housed in an uninflated and folded condition to minimize space requirements. Upon actuation of the system, the air bag cushion may be inflated with gas supplied or produced by a device commonly referred to as an “inflator.” Such inflators may typically be attached to a gas guide for the air bag cushion. As a result, conventional air bag cushions may include one or more features to facilitate attachment of the gas guide to the inflator. However, conventional inflators typically employ multiple components that may be individually formed (e.g., machined, forged, stamped, etc.) and attached together to provide a structure to facilitate attachment to the gas guide. 
     BRIEF SUMMARY 
     Various embodiments of the present disclosure comprise diffusers for use with an air bag cushion inflator having a reduced number of components resulting in a simplified, cheaper and more structurally sound diffuser. In one or more embodiments, a diffuser may comprise a unitary or integral hollow body defining a diffusion chamber. The hollow body may include a first longitudinal end having an aperture and an opposing second longitudinal end that is at least substantially enclosed. A module attach feature may be disposed between the first longitudinal end and the second longitudinal end. The module attach feature may comprise a lateral extent that is greater than a lateral extent of the hollow body. A plurality of apertures extending through the hollow body may be disposed between the module attach feature and the second longitudinal end. 
     Additional embodiments of the present disclosure include inflatable air bag systems. According to at least one embodiment, such system may comprise at least one inflatable cushion and an inflator. The inflator may include an elongated hollow tube with a first longitudinal tube end and a second longitudinal tube end. An initiator may be coupled to the first longitudinal tube end and a diffuser may be disposed at the second longitudinal tube end. The diffuser may be coupled to a portion of the at least one inflatable cushion. The diffuser may include a unitary hollow body comprising a first body end and a second body end that is at least substantially enclosed. An inflatable cushion attachment feature may be disposed between the first body end and the second body end, and may facilitate coupling the diffuser to the portion of the at least one inflatable cushion. A plurality of apertures may be disposed in the diffuser between the inflatable cushion attachment feature and the second body end. 
     Yet other embodiments of the present disclosure comprise methods of making a diffuser configured for use with an air bag cushion inflator. One or more embodiments of such methods may comprise forming a unitary hollow body. The unitary hollow body may be formed to include a first longitudinal end with an aperture therein and an opposing second longitudinal end that is at least substantially enclosed. A module attach feature may be disposed between the first longitudinal end and the second longitudinal end, such module attach feature having a lateral extent that is greater than a lateral extent of the hollow body. A plurality of apertures may be disposed in the hollow body and located between the module attach feature and the second longitudinal end. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       Exemplary embodiments of the disclosure will become more fully apparent from the following description and appended claims, taken in conjunction with the accompanying drawings. Understanding that these drawings depict only exemplary embodiments and are, therefore, not to be considered limiting of the disclosure&#39;s scope, the exemplary embodiments of the disclosure will be described with additional specificity and detail through use of the accompanying drawings in which: 
         FIG. 1  is a cross-sectioned side view of an air bag inflator according to at least one embodiment; 
         FIG. 2  is a cross-sectioned view of at least one embodiment of a diffuser including an integral module attach feature; 
         FIG. 3  is a cross-section view of at least one embodiment of a diffuser including a module attach feature adapted as a sleeve; and 
         FIG. 4  is a side view of the interior of a motor vehicle illustrating an inflatable air bag system according to at least one embodiment of the disclosure; 
         FIG. 5  is a flow chart illustrating at least one embodiment of a method of making a diffuser. 
     
    
    
     DETAILED DESCRIPTION 
     The illustrations presented herein are, in some instances, not actual views of any particular inflatable air bag system, air bag inflator, or diffuser, but are merely idealized representations which are employed to describe the present disclosure. Additionally, elements common between figures may retain the same numerical designation. 
     Various embodiments of the present disclosure include air bag cushion inflators including a unique diffuser.  FIG. 1  is a cross-sectioned view illustrating an air bag inflator  100  according to at least one embodiment of the present disclosure. The inflator  100  generally includes an elongated hollow tube  102  defining a chamber  104  for enclosing a quantity of fluid therein, designated by the reference numeral  106 . In the embodiment shown in  FIG. 1 , the fluid  106  may comprise a stored fluid, such as a pressurized expandable fluid. However, other embodiments of the inflator  100  may be adapted to enclose a quantity of gas generant adapted to be converted into a supply of inflation fluid during deployment, as well as a combination of stored fluid and gas generant, commonly referred to as a “hybrid”. 
     The hollow tube  102  includes opposing first and second longitudinal ends,  108  and  110 , respectively. An initiator  112  may be coupled to the first longitudinal end  108 , for instance as part of an initiator assembly  114 . Such an initiator assembly  114  may be coupled to the first longitudinal end  108  using, for example, an inertial weld  115 . The initiator  112  is adapted to inflate (e.g., ignite) the stored fluid  106  upon receipt of an electrical signal, such as may be generated by a sensor (not shown) upon the sensing of a collision. 
     The second longitudinal end  110  of the hollow tube  102  may be enclosed with a burst disk  116 . A diffuser  118  may be formed integral with or appropriately coupled to the second longitudinal end  110  of the hollow tube  102 . For example, the diffuser  118  may be coupled to the second longitudinal end  110  with an inertial weld  120 , or the diffuser  118  may be formed integral with the hollow tube  102 . Some examples of diffusers  118  are shown in  FIGS. 2 and 3 . 
     Referring to  FIG. 2 , the diffuser  118 A comprises a unitary hollow body  202  defining a diffusion chamber  204 . The hollow body  202  may include a first longitudinal end  206  and an enclosed, or substantially enclosed second longitudinal end  208 , which may also be characterized as a first body end  206  and second body end  208 , respectively. The first longitudinal body end  206  may be coupled to the second longitudinal end  110  of the inflator  100 , as shown in  FIG. 1 , and may include an aperture  210  enabling fluid communication between the chamber  104  of the inflator  100  and the diffusion chamber  204 . The aperture  210  may be sized and configured to control the rate of gas flow from the chamber  104  of the inflator  100  into the diffusion chamber  204 . In at least some embodiments, the first body end  206  may include a flange  212  adapted to facilitate coupling the diffuser  118 A to the inflator  100 . The flange  212  may comprise a crimp formed at the first body end  206  of the unitary hollow body  202  providing a substantial surface area to facilitate adhering (e.g., welding) the flange  212  to the second longitudinal end  110  of the hollow tube  102 . 
     According to at least one feature, the diffuser  118 A includes a module attach feature  216  disposed between the first body end  206  and the second body end  208 . The module attach feature  216  is adapted to facilitate attachment of the diffuser  118 A to a module of an inflatable air bag system, and may also be characterized as an inflatable cushion attachment feature. For example, the module attach feature  216  may facilitate attachment of the diffuser  118 A to a gas guide (e.g., hose  416  in  FIG. 4 ) for guiding an inflation fluid from the inflator  100 , through the diffuser  118 A and into one or more cells of an air bag cushion. 
     The module attach feature  216  may comprise a lateral extent  218  (e.g., an outer diameter of a cylindrically-shaped diffuser  118 A) that is greater than a lateral extent  220   a,    220   b  of the hollow body  202 . According to various embodiments, the lateral extent  218  of the module attach feature  216  may be sufficiently greater than the lateral extent  220   a  of the hollow body  202  (e.g., between the first body end  206  and the module attach feature  216 ) to facilitate retention of a module, such as a gas guide, of an inflatable air bag system. By way of example and not limitation, the lateral extent  218  of the module attach feature  216  may be greater than the lateral extent  220   a  of the hollow body  202  by about 5 mm or more. In some embodiments, the lateral extent  220   a  of the hollow body  202  between the first body end  206  and the module attach feature  216  may be larger than the lateral extent  220   b  of the hollow body  202  between the module attach feature  216  and the second body end  208 . The lateral extent  220   b  of the hollow body  202  (e.g., between the module attach feature  216  and the second body end  208 ) may be selected to provide sufficient clearance between the lateral extent  220   b  and a module (e.g., a gas guide) attached to the hollow body to facilitate the flow of a gas into the module (e.g., gas guide). By way of example and not limitation, the lateral extent  220   b  of the hollow body  202  may be adapted to provide a clearance of about 5 mm or more between the lateral extent  220   b  and an inner wall of a module (e.g., gas guide) of an inflatable air bag system attached to the diffuser  118 A. 
     The module attach feature  216  may be formed integral with the hollow body  202 , such that the entire diffuser  118  comprises a single unitary component. For example, the module attach feature  216  may comprise a portion or section of the hollow body  202  that has been folded outward, thereby forming an overlapped portion referred to herein as a crimped bend  222 . 
     The hollow body  202  may comprise a plurality of apertures  214  disposed between module attach feature  216  and the second body end  208 . In conventional diffusers, a filter may be disposed in the diffusion chamber  204  to filter out particulate that may be forced into the diffusion chamber  204  with an inflation fluid  106  (see  FIG. 1 ). By contrast, according to at least one feature, the plurality of apertures  214  may be sized and configured to filter particulate from an inflation fluid  106  (see  FIG. 1 ) passing through the apertures  214 , without the need for a separate filter. The diffuser  118  may, therefore, eliminate a separate filter by performing such filtering functions with the plurality of apertures  214 . Such apertures  214  may comprise any of a variety of shapes and sizes. For example, the apertures  214  may be circular, oval, rectangular, slot-shaped, etc. as well as any combination of two or more shapes. By way of example and not limitation, the plurality of apertures  214  according to one or more implementations may be circular, or substantially circular in shape, and may include diameters selected from the range between about 0.5 mm and about 2.5 mm. 
     Turning to  FIG. 3 , the diffuser  118 B is similar in many respects to the diffuser  118 A in  FIG. 2 . In general, as discussed in additional detail above, the diffuser  118 A includes a unitary hollow body  202  defining a diffusion chamber  204 , a first longitudinal end  206  with an aperture  210  and an enclosed, or substantially enclosed second longitudinal end  208 . The first body end  206  may include a flange  212 . A plurality of apertures  214  sized and configured to filter particulate from an inflation fluid passing through the apertures  214  may be disposed in the hollow body  202  between the second body end  208  and the module attach feature  216 . 
     One difference between the diffuser  118 A of  FIG. 2  and the diffuser  118 B of  FIG. 3  is the module attach feature  216  of the diffuser  118 B is not integral with the hollow body  202 . Instead, the module attach feature  216  comprises a component that may be disposed on an outer surface  302  of the hollow body  202 . For example, the module attach feature  216  may comprise a sleeve  304  disposed on the hollow body  202 , and may be configured with an L-shaped, or substantially L-shaped cross-section. 
     Additional embodiments of the present disclosure relate to inflatable air bag systems employing inflators having diffusers, such as those described above.  FIG. 4  is a side view of the interior of a motor vehicle illustrating an inflatable air bag system  400  according to at least one embodiment of the disclosure. The inflatable air bag system  400  includes an inflator, such as inflator  100  above, and a close proximity inflatable air bag cushion  402  in the form of an inflatable curtain. The inflatable air bag system  400  and the air bag cushion  402  thereof are intended to provide protection for a person  404  sitting in a seat  406  in the vehicle. In an accident in which the vehicle is decelerated, the person  404  may tend to move forwardly towards the steering wheel  408 , but may be restrained by a conventional seat belt and/or air bag. In the case of a side impact (e.g., side collision, roll-over), the person  404  may strike the window  410  in the door beside the person  404 , the vehicle B-pillar  412 , or both. There is also the risk that if the glass in the window  410  breaks, the head of the person  404  may be thrown out of the window opening. 
     The inflatable air bag cushion  402 , which may also be characterized as an inflatable cushion and is shown in the operative state in  FIG. 4 , is initially retained in a recess provided in the door frame  414  located above the door of the vehicle. The recess may extend over more than simply a linear portion of the door frame so that the two ends of the recess may not be in alignment with the main part of the recess. The inflator  100  is adapted to provide an inflation fluid to the air bag cushion  402  for its inflation. 
     The inflator  100  may be associated with a sensor (not shown) which senses a side impact situation and activates the inflator  100  (e.g., the initiator  112  in  FIG. 1 ) at the appropriate instant. The inflator  100  may include a diffuser  118  according to any of the embodiments described above (see, e.g.,  FIGS. 1-3 ). A module attach feature  216  (see  FIGS. 2 and 3 ) of the diffuser  118  may be connected by a hose  416  to a duct  418 , which duct  418  forms a part of the inflatable air bag cushion  402 . The air bag cushion  402  may include a plurality of cells  420  extending at least substantially parallel. 
     When an accident occurs, such as side impact, the inflator  100  produces, forms or otherwise supplies an inflation fluid, which is passed through the diffuser  118  into the hose  416  and then the duct  418  and inflates the cells  420 . The inflatable air bag cushion  402  thus moves from its initial stored position within the recess in the door frame  414  to the operative position shown in  FIG. 4 . That is, the air bag cushion extends downwardly from the top of the door frame  414  to form a generally flat structure located between at least a portion of the person  404  and a portion of the motor vehicle (e.g., between the head of the person  404  and the adjacent window  410  or B-pillar  412 ). 
     It is noteworthy, that while the embodiment described with reference to  FIG. 4  involves an air bag cushion adapted for use as an inflatable curtain  402 , other embodiments of inflatable air bag systems of the present disclosure may employ a number of other types of air bag cushions, including, but not limited to other side impact (e.g., head, thorax, combined) air bag cushions, knee air bag cushions, as well as other air bag cushions for use in a motor vehicle. 
     Further implementations of the present disclosure relate to methods of making a diffuser adapted for use with an air bag cushion inflator.  FIG. 5  is a flow chart illustrating at least one embodiment of a method  500  of making a diffuser, such as a diffuser  118 ,  118 A,  118 B of  FIGS. 1-3 . The steps associated with the method  500  of  FIG. 5  are described hereafter with reference to elements illustrated in  FIGS. 1-3  for illustrative purposes and not by way of limitation. Initially, a unitary hollow body  202  may be formed including first and second longitudinal ends (e.g., first longitudinal body end  206  and second longitudinal body end  208 , respectively)  502 . The first longitudinal end  206  may include an aperture  210  therein that is sized and configured to control the rate of gas flow into the hollow body  202 . The opposing second longitudinal end  208  may be at least substantially enclosed. In at least one implementation of method  500 , the hollow body  202  may be formed by deep draw stamping operations resulting in a unitary hollow body  202  having the aperture at the first longitudinal end  206  and an enclosed second longitudinal end  208 . 
     At operation block  504 , a module attach feature  216  may be disposed between the first longitudinal end  206  and the second longitudinal end  208 . The module attach feature  216  may include a lateral extend thereof that is greater than a lateral extent of the hollow body  202 . In at least some implementations, the module attach feature  216  may be formed integral to the unitary hollow body  202 . For example, the module attach feature  216  may be disposed in the hollow body  202  by folding a portion or section of the hollow body  202  outward, thereby forming an overlapped portion identified with reference to  FIG. 2  above as a crimped bend  222 . According to other implementations, the module attach feature  216  may be disposed between the first and second longitudinal ends  206 ,  208 , respectively, of the hollow body  202  by disposing a component on an outer surface of the hollow body  202 . For example, the module attach feature  216  may comprise a sleeve, such as sleeve  304  of  FIG. 3 , disposed on the hollow body  202 . In some embodiments, the sleeve  304  may comprise an L-shaped, or substantially L-shaped cross-section. 
     At operation block  506 , a plurality of apertures  214  may be disposed in the hollow body  202  such that the apertures  214  are located between the module attach feature  216  and the second longitudinal end  208 . The apertures  214  may be adapted to operate as a filter for the diffuser. For example, the apertures  214  may be sized and configured to filter particulate from an inflation fluid passing through the apertures. By way of example and not limitation, the plurality of apertures  214  may be formed to comprise a circular or oval shape and may include diameters selected from the range between about 0.5 mm and about 2.5 mm. 
     The various embodiments of the present disclosure result in diffusers that are unitary and may include integral filtering. Such unitary diffusers substantially reduce the costs associated with conventional diffusers having multiple separate components and are substantially easier and cheaper to manufacture. 
     The present invention may be embodied in other specific forms without departing from its structures, methods, or other essential characteristics as broadly described herein and claimed hereinafter. The described embodiments are to be considered in all respects only as illustrative, and not restrictive. The scope of the invention is, therefore, indicated by the appended claims, rather than by the foregoing description. All changes that come within the meaning and range of equivalency of the claims are to be embraced within their scope.