Filter with integrated baffle

• US 8,827,308 B1
• Filed: 03/15/2013
• Issued: 09/09/2014
• Est. Priority Date: 03/15/2013
• Status: Active Grant

• Current Assignee: Autoliv ASP Incorporated (Autoliv Incorporated)
• Original Assignee: Autoliv ASP Incorporated (Autoliv Incorporated)
• Inventors: Lewis, Robert E., Cox, Matthew A., Rasmussen, Kirk H.
• Primary Examiner(s): Dickson, Paul N
• Assistant Examiner(s): Freedman, Laura
• Application Number:
  US13/839,718
• Publication Number:
  US 20140261729A1
• Time in Patent Office: 543 Days
• Field of Search: 102/530, 280/736, 280740-742
• US Class Current: 280/736
• CPC Class Codes: B60R 2021/26011 using a filter through which the inflation gas passes
• CPC Class Codes: B60R 2021/2633 with a plurality of inflation levels
• CPC Class Codes: B60R 21/263 using a variable source, e.g. plural stage or controlled output hybrid inflators B60R21/272
• CPC Class Codes: B60R 21/272 with means for increasing the pressure of the gas just before or during liberation, e.g. hybrid inflators
• CPC Class Codes: Y10T 137/0402 Cleaning, repairing, or assembling
• CPC Class Codes: Y10T 137/3584 Inflatable article [e.g., tire filling chuck and/or stem]

Abstract

An airbag assembly may include an airbag and an inflator in fluid communication with the airbag. The inflator may have a first chamber containing a first gas source and a second chamber containing a second gas source. A filter module may be positioned to filter and redirect gas flows from the first and second gas sources. The filter module may be constructed by securing a baffle within an interior cavity of a filter medium having a generally tubular shape, prior to installation of the filter module the inflator. The baffle may be supported directly by the material of the filter module, by a bracket, or by a support structure formed of wire thicker than that of the filter medium. The baffle may maintain isolation between the first and second chambers, or may help gas from the first gas source initiate gas provision from the second gas source.

Claims

1. An inflator for an airbag assembly for protecting a vehicle occupant from injury, the inflator comprising:

an exterior wall comprising an aperture;

a first gas source contained within a first chamber defined within the exterior wall, wherein, in response to receipt by the inflator of a first activation signal, the first gas source provides a gas that defines a first gas flow pathway that moves through the inflator and exits the inflator via the aperture; and

a filter module positioned in the first gas flow pathway, the filter module comprising;

a filter medium having plurality of holes sized such that, as the gas flows through the filter medium, particulate matter entrained in the gas is trapped in the filter medium; and

a baffle secured to the filter medium, the baffle comprising an impingement surface positioned such that the gas impinges against the impingement surface in a manner that causes redirection of the first gas flow pathway;

wherein the baffle is positioned such that the baffle is in contact with no component of the inflator outside the filter module.

2. The inflator of claim 1, wherein the inflator further comprises a second gas source contained within a second chamber defined within the exterior wall, wherein, in response to receipt by the inflator of a second activation signal, the second gas source provides gas that defines a second gas flow pathway that moves through the inflator and exits the inflator via the aperture.

3. The inflator of claim 2, wherein the filter module is positioned in the second gas flow pathway, wherein the impingement surface is substantially planar and is oriented substantially perpendicular to the first gas flow pathway where the gas impinges against the impingement surface, wherein redirection of the first gas flow prevents the first gas flow from flowing directly into the second chamber through the filter module.

4. The inflator of claim 1, wherein the inflator further comprises a second gas source contained within a second chamber defined within the exterior wall, wherein, in response to entry of the first gas flow into the second chamber, the second gas source provides gas that defines a second gas flow pathway that moves through the inflator and exits the inflator via the aperture.

5. The inflator of claim 4, wherein the impingement surface defines a generally frusto-conical shape having an axis oriented substantially parallel to the first gas flow pathway where the gas impinges against the impingement surface, wherein redirection of the first gas flow directs the first gas flow into the second chamber to facilitate initiation of gas provision by the second gas source.

6. The inflator of claim 1, wherein the filter medium comprises a generally tubular shape comprising an interior surface that defines an interior cavity within which the baffle resides, wherein the baffle comprises a circumferential region captured directly by the interior surface.

7. The inflator of claim 1, wherein the filter medium comprises a generally tubular shape comprising an interior surface that defines an interior cavity within which the baffle resides, wherein the filter module further comprises a bracket captured by the interior surface, wherein the baffle comprises a circumferential region that abuts the bracket such that the bracket supports the baffle.

8. The inflator of claim 1, wherein the filter medium comprises a generally tubular shape comprising an interior surface that defines an interior cavity within which the baffle resides, wherein the filter medium is formed of a plurality of wires woven together, wherein the filter module comprises a support structure formed of a plurality of support wires that are significantly thicker than the plurality of wires of the filter medium, wherein the baffle comprises a circumferential region that abuts the support structure such that the support structure supports the baffle.

9. The inflator of claim 1, wherein the filter medium comprises a generally tubular shape comprising an interior surface that defines an interior cavity within which the baffle resides, the interior surface having ends on either side of the baffle, wherein the interior surface is tapered such that the filter medium is thicker where it surrounds the baffle than at the ends of the interior surface.

10. A method of manufacturing an inflator, the method comprising:

providing an exterior wall comprising an aperture;

providing a first gas source;

positioning the first gas source within a first chamber defined within the exterior wall such that, in response to receipt by the inflator of a first activation signal, the first gas source provides a gas that defines a first gas flow pathway that moves through the inflator and exits the inflator via the aperture;

providing a filter module comprising a filter medium having plurality of holes, and a baffle secured to the filter medium, the baffle comprising an impingement surface; and

positioning the filter module in the first gas flow pathway such that, as the gas flows through the filter medium, particulate matter entrained in the gas is trapped in the filter medium and the gas impinges against the impingement surface in a manner that causes redirection of the first gas flow pathway;

wherein providing the filter module comprises securing the baffle to the filter medium prior to positioning of the filter module in the first gas flow pathway.

11. The method of claim 10, further comprising:

providing a second gas source; and

positioning the second gas source within a second chamber defined within the exterior wall such that, in response to receipt by the inflator of a second activation signal, the second gas source provides gas that defines a second gas flow pathway that moves through the inflator and exits the inflator via the aperture.

12. The method of claim 11, wherein the impingement surface is substantially planar, wherein positioning the filter module in the first gas flow pathway comprises positioning the filter module in the second gas flow pathway and orienting the impingement surface substantially perpendicular to the first gas flow pathway where the gas impinges against the impingement surface, wherein redirection of the first gas flow prevents the first gas flow from flowing directly into the second chamber through the filter module.

13. The method of claim 10, further comprising:

providing a second gas source; and

positioning the second gas source within a second chamber defined within the exterior wall such that, in response to entry of the first gas flow into the second chamber, the second gas source provides gas that defines a second gas flow pathway that moves through the inflator and exits the inflator via the aperture.

14. The method of claim 13, wherein the impingement surface defines a generally frusto-conical shape, wherein positioning the filter module in the first gas flow pathway comprises orienting an axis of the frusto-conical shape substantially parallel to the first gas flow pathway where the gas impinges against the impingement surface, wherein redirection of the first gas flow directs the first gas flow into the second chamber to facilitate initiation of gas provision by the second gas source.

15. The method of claim 10, wherein the filter medium comprises a generally tubular shape comprising an interior surface that defines an interior cavity, wherein the baffle comprises a circumferential region, wherein securing the baffle to the filter medium comprises directly capturing the circumferential region with the interior surface.

16. The method of claim 10, wherein the filter medium comprises a generally tubular shape comprising an interior surface that defines an interior cavity, wherein the baffle comprises a circumferential region, wherein the filter module further comprises a bracket, wherein securing the baffle to the filter medium comprises:

capturing the bracket with the interior surface; and

positioning the baffle such that the circumferential region abuts the bracket such that the bracket supports the baffle.

17. The method of claim 10, wherein the filter medium comprises a generally tubular shape comprising an interior surface that defines an interior cavity, wherein the filter medium is formed of a plurality of wires woven together, wherein the filter module comprises a support structure formed of a plurality of support wires that are significantly thicker than the plurality of wires of the filter medium, wherein the baffle comprises a circumferential region, wherein securing the baffle to the filter medium comprises:

capturing the support structure with the interior surface; and

positioning the baffle such that the circumferential region abuts the support structure such that the support structure supports the baffle.

18. An inflator for an airbag assembly for protecting a vehicle occupant from injury, the inflator comprising:

an exterior wall comprising an aperture;

a first gas source contained within a first chamber defined within the exterior wall, wherein, in response to receipt by the inflator of a first activation signal, the first gas source provides a gas that defines a first gas flow pathway that moves through the inflator and exits the inflator via the aperture;

a second gas source contained within a second chamber defined within the exterior wall; and

a filter module positioned in the first gas flow pathway, the filter module comprising;

a filter medium having plurality of holes sized such that, as the gas flows through the filter medium, particulate matter entrained in the gas is trapped in the filter medium; and

a baffle secured to the filter medium, the baffle comprising an impingement surface positioned such that the gas impinges against the impingement surface in a manner that causes redirection of the first gas flow pathway;

wherein the filter medium comprises a generally tubular shape comprising an interior surface that defines an interior cavity within which the baffle entirely resides.

19. The inflator of claim 18, wherein, in response to receipt by the inflator of a second activation signal, the second gas source provides gas that defines a second gas flow pathway that moves through the inflator and exits the inflator via the aperture, wherein the filter module is positioned in the second gas flow pathway, wherein the impingement surface is substantially planar and is oriented substantially perpendicular to the first gas flow pathway where the gas impinges against the impingement surface, wherein redirection of the first gas flow prevents the first gas flow from flowing directly into the second chamber through the filter module.

20. The inflator of claim 18, wherein, in response to entry of the first gas flow into the second chamber, the second gas source provides gas that defines a second gas flow pathway that moves through the inflator and exits the inflator via the aperture, wherein the impingement surface defines a generally frusto-conical shape having an axis oriented substantially parallel to the first gas flow pathway where the gas impinges against the impingement surface, wherein redirection of the first gas flow directs the first gas flow into the second chamber to facilitate initiation of gas provision by the second gas source.