Inflator and airbag module

• US 9,511,738 B2
• Filed: 11/03/2015
• Issued: 12/06/2016
• Est. Priority Date: 10/15/2010
• Status: Active Grant

• Current Assignee: TRW Airbag Systems GmbH (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Original Assignee: TRW Airbag Systems GmbH (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Inventors: Bierwirth, Sebastian, Hofmann, Achim, Neumayer, Hans-Peter, Spitzenberger, Dieter, Nuiding, Hannes, Schober, Thomas, Bommer, Josef, Breddermann, Tobias, Schwebel, Dietmar
• Primary Examiner(s): GOODEN JR, BARRY J
• Application Number:
  US14/930,936
• Publication Number:
  US 20160052484A1
• Time in Patent Office: 399 Days
• US Class Current: 1/1
• CPC Class Codes: B60R 2021/26011 using a filter through which the inflation gas passes
• CPC Class Codes: B60R 2021/26029 Ignitors
• CPC Class Codes: B60R 2021/2633 with a plurality of inflation levels
• CPC Class Codes: B60R 2021/2648 comprising a plurality of combustion chambers or sub-chambers
• CPC Class Codes: B60R 21/261 with means other than bag structure to diffuse or guide inflation fluid
• 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 21/264 using instantaneous generation of gas, e.g. pyrotechnic B60R21/268 takes precedence
• CPC Class Codes: B60R 21/2644 using only solid reacting substances, e.g. pellets, powder

Abstract

An inflator for a protective device in a vehicle includes a diffuser (10) forming a substantially rotation-symmetric external housing of the inflator with a closing member (12), wherein the diffuser (10) includes a plurality of discharge orifices (78) arranged in a row, and which are of circular shape. The inflator also includes a filter (46) and a combustion chamber component at least partially enclosing at least one of a combustion chamber (56) and a combustion chamber sleeve (60), wherein the filter (46) extends in a ring-shaped manner about the combustion chamber (56) and, at a position of its ring-shaped extension, includes a critical filter portion (120) which is closer to the combustion chamber component than the remaining filter areas situated at its ring-shaped extension, wherein the critical filter portion (120) has a reduced thickness compared to areas of the filter that are adjacent to the critical filter portion (120).

Claims

1. An inflator for a protective device in a vehicle, comprising

a diffuser cooperating with a closing member to form an external housing of the inflator, wherein the diffuser includes a plurality of discharge orifices;

a combustion chamber component at least partially enclosing a combustion chamber; and

a ring-shaped filter extending about an axis and the combustion chamber, the filter including a critical filter portion positioned closest to the combustion chamber component that has a reduced radial thickness compared to a remainder of the filter such that the filter is asymmetric about the axis.

2. The inflator according to claim 1, wherein the radial cross-section of the critical filter portion is different from the radial cross-section of the remainder of the filter.

3. An inflator for a protective device in a vehicle, comprising

a diffuser forming a substantially rotation-symmetric external housing of the inflator with a closing member, wherein the diffuser includes a plurality of discharge orifices arranged in a row, and which are of circular shape;

and

a filter and a combustion chamber component at least partially enclosing a combustion chamber, wherein the filter extends in a ring-shaped manner about an axis and the combustion chamber and includes a critical filter portion which is closer to the combustion chamber component than a remaining area of the filter, wherein the critical filter portion has a reduced thickness compared to areas of the filter that are adjacent to the critical filter portion such that the filter is asymmetric about the axis.

4. The inflator according to claim 3, wherein between the combustion chamber component and the critical filter portion a gap is formed;

wherein a material of which the filter is made is compressed more highly in the critical filter portion than in the adjacent areas;

wherein the combustion chamber component has an increased material thickness at least in an area opposed to the critical filter portion;

wherein the filter extends along a circumferential wall of the inflator surrounding a chamber of the inflator in which the combustion chamber component is disposed; and

wherein the combustion chamber component extends over a larger axial height than the filter, the combustion chamber component substantially exhibiting an increased material thickness only in an axial area in which also the filter extends.

5. The inflator according to claim 3, wherein a gap is formed between the combustion chamber component and the critical filter portion;

wherein a ratio of the minimum thickness (j) of the critical filter portion to a thickness of the adjacent areas of the filter is between 0.43 and 0.93;

wherein a ratio of a minimum thickness of the critical filter portion to a maximum width of the gap is between 1.17 and 2.85; and

wherein the inflator is closed at a first axial end face by a substantially axially extending circumferential wall of the diffuser, wherein the filter extends in an axial direction beyond the circumferential wall.

6. The inflator according to claim 3, further comprising a radially projecting generator flange, related to a central axis (A) of the inflator, for mounting the inflator to a support, wherein the generator flange is substantially rectangular;

wherein a ratio of a length (l) to the width (b) of the rectangle ranges between 1.12 and 1.31;

wherein a ratio of the length (l) of the rectangle to an outer diameter (a) of the external housing ranges between 1.24 and 1.48; and

wherein a ratio of the width (b) of the rectangle to the outer diameter (a) of the external housing is between 1.01 and 1.23.

7. The inflator according to claim 3, wherein at least in portions a wall thickness of the closing member is larger than that of the diffuser, wherein the closing member has a substantially planar bottom in which at least one opening for receiving an igniter carrier is formed and that at least the bottom has a larger wall thickness than the diffuser.

8. The inflator according to claim 3, wherein the diffuser includes a ceiling portion and the combustion chamber component contacts the ceiling portion of the diffuser in a non-activated state of the inflator at least at one point, and wherein, related to a central axis (A) of the diffuser, an axial distance between the combustion chamber component and the ceiling portion is varying such that a maximum distance between the combustion chamber component and the ceiling portion of the diffuser is between 2.3 and 3.7 mm.

9. The inflator according to claim 3, wherein an igniter sleeve offset with respect to a central axis (A) of the diffuser whose axial distance (i) from a ceiling portion of the diffuser is varying such that the maximum distance (i) between the igniter sleeve and the ceiling portion of the diffuser is between 2.1 and 3.5 mm.

10. An airbag module for a vehicle comprising an airbag having a volume of 40 to 60 liters, comprising an inflator according to claim 3.

11. An airbag module for a vehicle comprising an airbag having a volume of 60 to 135 liters, comprising inflator according to claim 3.

12. The inflator according to claim 3, wherein the radial cross-section of the critical filter portion is different from the radial cross-section of the remainder of the filter.

13. The inflator according to claim 3, further comprising an igniter unit, wherein the igniter unit has a marker, wherein the marker is a milled slot, and wherein the marker sets a predetermined orientation of connecting pins of the igniter unit.

14. The inflator according to claim 13, wherein the igniter unit is a pre-assembled unit having an igniter carrier and an igniter held therein which is adapted to be inserted in a bottom orifice of the closing member of the inflator.

15. The inflator according to claim 3, further comprising a fuel canister filled with fuel including a fuel canister bottom and a fuel canister opening opposed to the fuel canister bottom which is closed by the combustion chamber component.

16. The inflator according to claim 15, wherein the combustion chamber component is a combustion chamber sleeve which encloses at least partially the combustion chamber associated with a particular activating stage of the inflator, wherein the combustion chamber sleeve exhibits a combustion chamber sleeve opening or an open side and a combustion chamber sleeve bottom opposed thereto which covers the fuel canister opening, wherein a second fill member connected to the combustion chamber sleeve bottom is arranged at the combustion chamber sleeve bottom;

and

wherein at least part of a side wall of the fuel canister extending between the fuel canister opening and the fuel canister bottom is directly opposed to at least part of a side wall of the combustion chamber sleeve extending between the combustion chamber sleeve orifice or the open side of the combustion chamber sleeve and the combustion chamber sleeve bottom.

17. The inflator according to claim 15, wherein the fuel canister and the combustion chamber component are two open substantially cylindrical sleeves which are inserted into each other at opposed orientation so that an inner or outer shell of the fuel canister and an outer or inner shell of the combustion chamber component substantially cover each other over an entire axial length of the shells, the combustion chamber component being slipped onto an outside of the fuel canister.

18. The inflator according claim 15, wherein in the fuel canister bottom a central fuel canister bottom opening is formed for receiving an igniter carrier, wherein the fuel canister bottom opening is formed by a bent inner edge portion extending from the fuel canister bottom into an interior of the fuel canister.

19. The inflator according to claim 15, wherein plural holes are formed in the fuel canister bottom, and wherein the combustion chamber component is free of holes, apart from a combustion chamber component orifice or the open side, and wherein the combustion chamber component is slipped onto an igniter carrier.

20. An inflator for a protective device in a vehicle, comprising:

a diffuser forming a substantially rotation-symmetric external housing of the inflator with a closing member, wherein the diffuser includes a plurality of discharge orifices arranged in a row, and which are of circular shape;

a filter and a combustion chamber component at least partially enclosing a first combustion chamber, wherein the filter extends in a ring-shaped manner about the first combustion chamber and includes a critical filter portion which is closer to the combustion chamber component than a remaining area of the filter, wherein the critical filter portion has a reduced thickness compared to areas of the filter that are adjacent to the critical filter portion;

wherein the first combustion chamber is filled with fuel which is associated with a first activating stage of the inflator and is closed on one side by the diffuser, wherein a first fill member is disposed between the fuel and the diffuser,

wherein the first fill member has at least one circular recess into which an igniter sleeve associated with the first activating stage of the inflator or a combustion chamber sleeve associated with a second activating stage of the inflator projects;

wherein the first fill member has two recesses of different size, wherein the igniter sleeve projects into a smaller recess and the combustion chamber sleeve projects into a larger recess;

wherein a ratio of the diameter of the larger recess to the diameter of the smaller recess is between 1.52 and 2.25; and

wherein the first fill member is designed in at least two parts that each has a shape of a double half moon.