Inflator and airbag module

• US 9,643,564 B2
• Filed: 11/03/2015
• Issued: 05/09/2017
• 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:
  US14/930,807
• Publication Number:
  US 20160052482A1
• Time in Patent Office: 553 Days
• 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 combustion chamber sleeve (60) which at least partially encloses a combustion chamber (56) filled with fuel, wherein the combustion chamber sleeve (60) is designed such that it changes its shape by pressure formed during combustion of the fuel so as to release a discharge orifice (112) leading out of the combustion chamber (56) into a further combustion chamber (44) of the inflator, for a combustion gas formed during combustion of the fuel.

Claims

1. 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 combustion chamber sleeve which at least partially encloses a combustion chamber filled with fuel, the combustion chamber sleeve extending along a central axis and having a first end abutting the diffuser at a contact point and a second end positioned at an axial extent of the combustion chamber opposite the contact point, wherein the combustion chamber sleeve is designed to tilt about the contact point in response to pressure formed during combustion of the fuel so as to release a discharge orifice at the second end leading out of the combustion chamber into a further combustion chamber of the inflator, for a combustion gas formed during combustion of the fuel.

2. The inflator according to claim 1, wherein the combustion chamber sleeve is attached to an igniter carrier, and the discharge orifice is formed by the fact that the combustion chamber sleeve detaches at least partially from the supporting component so that a discharge gap is formed between the combustion chamber sleeve and the supporting component, and wherein, related to a central axis (C) of the combustion chamber sleeve, the discharge gap is formed to be not completely circumferential or at least not to have a constant width, wherein the discharge gap has its largest width in an area facing away from a filter disposed outside the combustion chamber or has the largest possible distance from the filter.

3. The inflator according to claim 1, 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 the ratio of the length (l) to the width (b) of the rectangle ranges between 1.12 and 1.31;

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

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

4. The inflator according to claim 1, wherein at least in portions the wall thickness of the closing member is larger than that of the diffuser, wherein the closing member has a substantially plane 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.

5. The inflator according to claim 1, wherein the diffuser includes a ceiling portion, wherein the combustion chamber sleeve 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, the axial distance (g) between the combustion chamber sleeve and the ceiling portion is varying such that the maximum distance (g) between the combustion chamber sleeve and the ceiling portion of the diffuser is between 2.3 and 3.7 mm.

6. The inflator according to claim 1, wherein an igniter sleeve offset with respect to the central axis (A) of the diffuser whose axial distance (i) from the 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.

7. An airbag module for a vehicle comprising an airbag having a volume of 40 to 60 liters, comprising an inflator according to claim 1.

8. An airbag module for a vehicle comprising an airbag having a volume of 60 to 135 liters, comprising inflator according to claim 1.

9. The inflator according to claim 1, wherein the combustion chamber constitutes

a first combustion chamber associated with a first activating stage of the inflator, a second combustion chamber associated with a second activating stage of the inflator, wherein the second combustion chamber is surrounded at least partially by the first combustion chamber and has a smaller volume than the first combustion chamber;

wherein a ratio of a volume of the first combustion chamber to the volume of the second combustion chamber is between 2.07 and 3.78;

wherein the ratio of the volume of the first combustion chamber to the volume of an igniter sleeve at least partially surrounded by the first combustion chamber is between 9.00 and 35.0;

wherein a ratio of the outer diameter (a) of an external housing of the inflator to an axial height (h₁) of the external housing is between 1.38 and 1.78; and

wherein the axial height (h₁) of the external housing of the inflator, is between 30 and 50 mm.

10. The inflator according to claim 1, wherein the combustion chamber constitutes

a first combustion chamber associated with a first activating stage of the inflator, a second combustion chamber being associated with a second activating stage of the inflator, wherein the second combustion chamber is surrounded at least partially by the first combustion chamber and has a smaller volume than the first combustion chamber, wherein the ratio of the volume of the first combustion chamber to the volume of the second combustion chamber is between 2.34 and 3.27;

wherein a ratio of a volume of the first combustion chamber to the volume of an igniter sleeve at least partially surrounded by the first combustion chamber ranges between 13.5 and 31.0;

wherein a ratio of an outer diameter (a) of an external housing of the inflator to the height (h₁) of the external housing ranges between 0.94 and 1.16; and

wherein the axial height (h₁) of the external housing of the inflator, ranges between 50 and 70 mm.

11. The inflator according to claim 1 further comprising an igniter carrier attached to and engaging the combustion chamber sleeve, wherein the combustion of the fuel causes the combustion chamber sleeve to move relative to the igniter carrier to form a discharge gap therebetween that defines the discharge orifice.

12. The inflator recited in claim 1, wherein the discharge orifice is positioned at the axial extent of the combustion chamber opposite the contact point.

13. The inflator according to claim 1, wherein the combustion chamber sleeve is slipped onto a fuel canister filled with fuel and having a fuel canister bottom including one or more holes through which the combustion gas flows to the discharge orifice, wherein the bole or holes in the fuel canister bottom are formed as late as by the pressure developed during the combustion of the fuel and tearing of the fuel canister bottom caused thereby.

14. The inflator according to claim 13, wherein before the combustion of the fuel the combustion chamber sleeve has no discharge orifice, and wherein due to the pressure the combustion chamber sleeve moves toward a ceiling portion of the diffuser, wherein the movement is restricted by the ceiling portion and uneven deformation of the combustion chamber sleeve is caused by the pressure.

15. The inflator according to claim 1, 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 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 sleeve 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 sleeve substantially cover each other over the entire axial length of the shells, the combustion chamber sleeve being slipped onto the 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 the interior of the fuel canister.

19. An inflator for a protective device in a vehicle comprising:

a diffuser forming an external housing of the inflator with a closing member, wherein the diffuser includes a ceiling portion and a plurality of discharge orifices;

an igniter carrier; and

a combustion chamber sleeve which at least partially encloses a combustion chamber filled with fuel, the combustion chamber sleeve extending along a central axis and having a closed first end adjacent the ceiling portion and an open second end adjacent the igniter carrier and positioned at an axial extent of the combustion chamber opposite the ceiling portion, wherein the combustion chamber sleeve is configured to at least one of deform and become displaced in response to pressure formed during combustion of the fuel so that the second end moves relative to the igniter carrier to create a discharge orifice located between and defined by the second end and the igniter carrier that leads out of the combustion chamber into a further combustion chamber of the inflator outside the combustion chamber sleeve.

20. The inflator recited in claim 19, wherein the second end of the combustion chamber sleeve abuts the igniter carrier prior to combustion of the fuel.

21. The inflator recited in claim 19, wherein the discharge orifice is positioned at the axial extent of the combustion chamber opposite the ceiling portion and adjacent the igniter carrier.

22. The inflator recited in claim 19, wherein the combustion chamber sleeve is configured such that the closed first end engages the ceiling portion of the diffuser at a contact point on a periphery of the sleeve such that the combustion chamber sleeve tilts about the contact point in response to the pressure formed during combustion of the fuel.

23. The inflator recited in claim 22, wherein the discharge orifice at the open second end is largest at a location diametrically opposite the contact point.

24. 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 combustion chamber sleeve which at least partially encloses a combustion chamber filled with fuel, wherein the combustion chamber sleeve is designed such that it changes its shape by pressure formed during combustion of the fuel so as to release a discharge orifice leading out of the combustion chamber into a further combustion chamber of the inflator, for a combustion gas formed during the combustion of the fuel; and

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.

25. The inflator according to claim 24, 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 a closing member of the inflator.

26. 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 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 sleeve; and

a combustion chamber sleeve which at least partially encloses a combustion chamber filled with fuel, the combustion chamber sleeve extending along a central axis and having a first end abutting the diffuser at a contact point and an opposite second end,

wherein plural holes are formed in the fuel canister bottom, and wherein the combustion chamber sleeve is free of holes, apart from the combustion chamber sleeve orifice or the open side, and wherein the combustion chamber sleeve is slipped onto an igniter carrier;

wherein the combustion chamber sleeve is designed to tilt about the contact point in response to pressure formed during combustion of the fuel so as to release a discharge orifice at the second end leading out of the combustion chamber into a further combustion chamber of the inflator, for a combustion gas formed during the combustion of the fuel.

27. 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 combustion chamber sleeve which at least partially encloses a combustion chamber filled with fuel, wherein the combustion chamber sleeve is designed such that it changes its shape by pressure formed during combustion of the fuel so as to release a discharge orifice leading out of the combustion chamber into a further combustion chamber of the inflator, for a combustion gas formed during the combustion of the fuel;

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

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 the 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 the smaller recess and the combustion chamber sleeve projects into the larger recess;

wherein the 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, each of the two partial members has the shape of a double half moon.