Inflator and airbag module

Patent metadata

Field	Value
Publication number	US-9643564-B2
Application number	US-201514930807-A
Country	US
Kind code	B2
Filing date	Nov 3, 2015
Priority date	Oct 15, 2010
Publication date	May 9, 2017
Grant date	May 9, 2017

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.

First claim

The invention claimed is:

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 (h 1 ) of the external housing is between 1.38 and 1.78; and
wherein the axial height (h 1 ) 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 (h 1 ) of the external housing ranges between 0.94 and 1.16; and
wherein the axial height (h 1 ) 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 connec

Assignees

• Trw Airbag Sys Gmbh

Inventors

• Bierwirth Sebastian
• Hofmann Achim
• Neumayer Hans-Peter
• Spitzenberger Dieter
• Nuiding Hannes
• Schober Thomas
• Bommer Josef
• Breddermann Tobias
• Schwebel Dietmar

Classifications

• B60R2021/2633

  with a plurality of inflation levels · CPC title

• B60R2021/26029

  Ignitors · CPC title

• B60R21/2644

  using only solid reacting substances, e.g. pellets, powder · CPC title

• B60R2021/2648

  comprising a plurality of combustion chambers or sub-chambers · CPC title

• B60R21/264

  using instantaneous generation of gas, e.g. pyrotechnic (B60R21/268 takes precedence) · CPC title