Filter for use in a gas generator

• US 20080264022A1
• Filed: 01/28/2008
• Published: 10/30/2008
• Est. Priority Date: 02/05/2007
• 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: Zengerle, Werner, Schwuchow, Karsten, Schreiber, Simon
• Granted Patent: US 8,585,792 B2
• Time in Patent Office: Days
• US Class Current: 55/520
• CPC Class Codes: B01D 2279/10 for air bags, e.g. inflators therefor
• CPC Class Codes: B01D 39/12 of wire gauze; of knitted wire; of expanded metal
• CPC Class Codes: B01D 46/2411 Filter cartridges
• CPC Class Codes: B01D 46/528 using wound sheets B01D46/527 takes precedence
• CPC Class Codes: B60R 2021/26011 using a filter through which the inflation gas passes
• CPC Class Codes: B60R 21/2644 using only solid reacting substances, e.g. pellets, powder
• CPC Class Codes: Y10T 29/49604 Filter

Abstract

A filter for use in a gas generator of a safety arrangement in vehicles, has several layers of a woven metal fabric consisting of metal wires which are woven together. The woven metal fabric is preferably calendered, wound to form a roll, and pressed to form said filter.

Claims

1. A filter adapted for use in a gas generator of a safety arrangement in vehicles, the filter comprising two or more layers of a woven metal fabric, wherein the metal fabric consists of metal wires which are woven together, and wherein the woven metal fabric is wound to form a roll, and pressed.

2. The filter according to claim 1, wherein the woven metal fabric is calendered.

3. The filter according to claim 1, wherein the metal wires have a wire diameter of approximately 0.4 mm to 1.5 mm.

4. The filter according to claim 1, wherein the woven metal fabric has a mesh width which is approximately double the wire diameter.

5. The filter according to claim 1, wherein the woven metal fabric has a mesh width of approximately 0.8 mm to 4 mm.

6. The filter according to claim 1, wherein the woven metal fabric has a basket weave or a twill weave.

7. The filter according to claim 1, wherein the filter has a uniform peripheral thickness.

8. The filter according to claim 1, wherein the filter has an eccentric shape.

9. The filter according to claim 1, wherein the filter is constructed in a tubular shape and has a closed end.

10. The filter according to claim 1, wherein the filter consists of two or more layers of a woven metal fabric, wherein the woven metal fabric has a surface, and the woven metal fabric is calendered to flatten said surface.

11. A gas generator for use in a safety arrangement for vehicles, comprising a combustion chamber containing a propellant for generating a hot gas, and a filter associated with the combustion chamber, for cooling and cleaning the gas of solid particles, wherein said filter comprises two or more layers of a woven metal fabric, wherein the metal fabric consists of metal wires which are woven together, and wherein the woven metal fabric is wound to form a roll and pressed to form said filter.

12. The gas generator according to claim 11, characterized in that the woven metal fabric is calendered.

13. The gas generator according to claim 12, wherein said woven metal fabric has a surface, and said woven metal fabric is calendered to flatten said surface.

14. A method for the production of a filter for use in a gas generator for a safety arrangement in vehicles, comprising the following steps:

providing a blank of a woven metal fabric;

winding the blank of the woven metal fabric to form a roll of a multi-layered woven metal fabric;

pressing the roll of the multi-layered woven metal fabric thereby forming the filter.

15. The method according to claim 14, wherein in that the blank has a ratio of length (I) to width (b) of at least 2:

1.

16. The method according to claim 14, wherein the multi-layered woven metal fabric is arranged in a spiral shape in the roll and has a substantially whole-numbered number of windings.

17. The method according to claim 16, wherein the free ends of the blank of the woven metal fabric do not overlap in the roll and lie within a sector having a mid-point angle α

of between 5 and 30°

.

18. The method according to claim 14, wherein characterized in that the woven metal fabric is wound in the longitudinal direction (I) of the blank and the roll of the multi-layered woven metal fabric is pressed substantially perpendicularly to the longitudinal direction (I) of the blank.

19. The method according to claim 14, wherein after said pressing step, the filter has a volume which is approximately 50% or more of the volume of the roll of the multi-layered woven metal fabric.

20. The method according to claim 14, wherein after said pressing step, the volume of the filter is between approximately 70 and 80%, preferably about 75% of the volume of the roll of the multi-layered metal fabric.

21. The method according to claim 14, wherein the step of pressing of the roll of the multi-layered woven metal fabric takes place with a pressing density which is locally differentially distributed.

22. The method according to claim 21, wherein the pressing density is greater radially outward than radially inward.

23. The method according to claim 14, wherein prior to the step of winding the blank of the woven metal fabric to a roll, the blank of said woven metal fabric is compactly rolled and calendered to form a calendered fabric web having a flattened fabric web surface.