Filter for use in a gas generator

• US 8,585,792 B2
• Filed: 01/28/2008
• Issued: 11/19/2013
• 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, Schreiber, Simon, Schwuchow, Karsten
• Primary Examiner(s): Smith, Duane
• Assistant Examiner(s): MCKENZIE, THOMAS B
• Application Number:
  US12/011,542
• Publication Number:
  US 20080264022A1
• Time in Patent Office: 2,122 Days
• Field of Search: 964/21, 553/853, 554/95, 555/22, 555/27, 55D/IG.5, 555/20, 55525-526, 55D/IG.45, 2807281-7431, 148/14, 141 14- 17, 141/59, 141/98, 166227-236, 422164-167, 102530-531, 102/282, 102/430, 102/202, 1022025-20214, 102/204, 264/DIG.48, 222/3, 222/5, 242360-363
• US Class Current: 55/385.3
• 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 method for the production of a filter for subsequent use in a gas generator for a safety arrangement in vehicles, comprising the following steps:

providing a flat 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 having a central longitudinal axis about which the blank is wound, the blank being wound about the central longitudinal axis such that free ends of the roll do not overlap in the roll and lie within a sector having a mid-point angle, α

, of between 5 and 30°

with respect to said longitudinal axis;

pressing the roll of the multi-layered woven metal fabric in the direction of the central longitudinal axis thereby forming the filter.

2. The method according to claim 1, wherein in that the blank has a ratio of length (l) to width (b) of at least 2:

1.

3. The method according to claim 1, 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.

4. The method according to claim 1, wherein the woven metal fabric is wound in the longitudinal direction (l) of the blank and the roll of the multi-layered woven metal fabric is pressed substantially perpendicularly to the longitudinal direction (l) of the blank.

5. The method according to claim 1, 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.

6. The method according to claim 1, 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.

7. The method according to claim 1, 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.

8. The method according to claim 7, wherein the pressing density is greater radially outward than radially inward.

9. The method according to claim 1, 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.

13. The method according to claim 1, wherein the flat blank of woven metal fabric has a periodic spatial structure that is maintained when wound to form the roll and when pressed to form the filter thereby causing the filter to have a substantially uniform pore volume.

14. The method according to claim 1, wherein the step of pressing the roll comprises applying a compressive force to the roll sufficient to reduce the mesh width of the woven metal fabric.

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

providing a flat blank of a woven metal fabric having a periodic spatial structure;

winding the blank of the woven metal fabric to form a roll of a multi-layered woven metal fabric having a central longitudinal axis about which the blank is wound, the blank being wound about the central longitudinal axis such that a wall thickness, V, of one segment of the winding body is smaller than the thickness, W, of an opposite segment of the winding body, and such that the periodic spatial structure of the woven fabric is maintained;

pressing the roll of the multi-layered woven metal fabric in the direction of the central longitudinal axis thereby forming the filter, the periodic spatial structure of the woven metal fabric when pressed being maintained and thereby causing the filter to have a substantially uniform pore volume.

15. The method according to claim 10, wherein the step of pressing the roll comprises applying a compressive force to the roll sufficient to reduce the mesh width of the woven metal fabric.

17. The method according to claim 10, wherein the step of providing a flat blank of a woven metal fabric having a periodic spatial structure comprises the step of calendering the woven metal fabric.

11. An occupant restraint system comprising:

an air bag; and

an inflator for inflating the air bag, the inflator comprising a filter, the filter comprising;

a flat blank of a woven metal fabric that is wound about a central longitudinal axis to form a roll of multi-layered woven metal fabric, the blank being wound about the central longitudinal axis such that free ends of the roll do not overlap in the roll and lie within a sector having a mid-point angle, α

, of between 5 and 30°

with respect to the longitudinal axis, the roll of multi-layered woven metal fabric being pressed prior to assembly of the inflator in the direction of the central longitudinal axis to form the filter.

18. The system according to claim 11, wherein the flat blank of woven metal fabric comprises a calendered woven metal fabric.

12. An occupant restraint system comprising:

an air bag; and

an inflator for inflating the air bag, the inflator comprising a filter, the filter comprising;

a flat blank of a woven metal fabric having a periodic spatial structure that is wound about a central longituinal axis to form a roll of multi-layered woven metal fabric, the blank being wound about the central longitudinal axis such that a wall thickness, V, of one segment of the winding body is smaller than the thickness, W, of an opposite segment of the winding body, and such that the periodic spatial structure of the woven fabric is maintained, the roll of the multi-layered woven metal fabric being pressed in the direction of the central longitudinal axis to form the filter, the periodic spatial structure of the woven metal fabric when pressed being maintained and thereby causing the filter to have a substantially uniform pore volume.

19. The system according to claim 12, wherein the flat blank of woven metal fabric comprises a calendered woven metal fabric.

16. An occupant restraint system comprising:

an air bag; and

an inflator for inflating the air bag, the inflator comprising a filter, the filter comprising;

a flat blank of a woven metal fabric that is wound about a central longitudinal axis to form a roll of multi-layered woven metal fabric, the blank being wound about the central longitudinal axis such that free ends of the roll do not overlap in the roll and lie within a sector having a mid-point angle, α

, of between 5 and 30°

with respect to the longitudinal axis, the roll of multi-layered woven metal fabric being pressed in the direction of the central longitudinal axis to form the filter, wherein the flat blank of woven metal fabric has a periodic spatial structure that is maintained when wound to form the roll and when pressed to form the filter thereby causing the filter to have a substantially uniform pore volume.