AIRBAG DEVICE

• US 20090200778A1
• Filed: 02/26/2007
• Published: 08/13/2009
• Est. Priority Date: 02/27/2006
• Status: Active Grant

• Current Assignee: Ashimori Industry Company Limited, Mazda Motor Corporation
• Original Assignee: Ashimori Industry Company Limited, Mazda Motor Corporation
• Inventors: Moritani, Keisuke, Yamaji, Naoki, Hashizume, Tomoki, Ishikawa, Toshihiro, Soemoto, Kazuhiko
• Granted Patent: US 7,997,614 B2
• Time in Patent Office: Days
• US Class Current: 280/739
• CPC Class Codes: B60R 2021/23382 Internal tether means
• CPC Class Codes: B60R 21/2338 Tethers
• CPC Class Codes: B60R 21/239 characterised by their venting means
• CPC Class Codes: B60R 21/36 using airbags

Abstract

Intended is to always provide effective impact reduction by releasing gas at a timing of pushing into airbag.

An airbag (10) has a vent hole (18) in one side end portion. One end of a third base fabric (20) is sewn to the airbag (10) through a first sewn portion (23) that closes the vent hole (18), and the other end of the third base fabric 20 is sewn to the other side end portion of the airbag (10) through a second sewn portion (24). The first sewn portion (23) has weaker binding force by sewing than the second sewn portion (24) so that the first sewn portion (23) is separated to open the vent hole (18) when tension force is applied from the third base fabric (20) to the first and second sewn portions (23) and (24).

Claims

1. An airbag device comprising an airbag inflatable with gas generated by an inflator, the airbag having a front surface base fabric and a back surface base fabric,

wherein the airbag has a first vent hole through which gas is discharged,

wherein the airbag further has a third base fabric that covers a surface of the airbag and restricts inflation of the airbag during inflation,

wherein the first vent hole is closed by a sewn portion being sewn by a thread to the front and back surface base fabrics of the airbag, and

wherein, while the airbag is in an inflated state, the thread of the one sewn portion of the third base fabric is broken and the first vent hole is opened, by the further inflation of the airbag resulting from pushing into the third base fabric by a person.

2. The airbag device according to claim 1,

wherein both sides of the third base fabric are sewn by a thread to the front and back surface base fabrics of the airbag, and at least one end of the sewn portions of the third base fabric is provided near a boundary between a portion where inflation is restricted by the third base fabric of the airbag when a person pushes into the third base fabric of the airbag in an inflated state, and a portion adjacent thereto where inflation is not restricted.

3. The airbag device according to claim 2,

wherein the airbag further has a second vent hole through which gas is discharged, the second vent hole being provided at a certain distance from the first vent hole, and

wherein the second vent hole is closed by the other sewn portion between the sewn portions of the third base fabric.

4. The airbag device according to claim 2,

wherein the other sewn portion has a greater binding force by sewing than the one sewn portion between the sewn portions of the third base fabric.

5. The airbag device according to claim 2,

wherein each of the sewn portions includes a first sewn portion where an opening portion of the vent hole is sewn in a straight line, and a second sewn portion connected to the first sewn portion, where a portion adjoining the second opening portion of the vent hole is sewn by a thread in a zigzag line, and

wherein breaking forces of the thread of the sewn portions are differentiated by changing the length of the second sewn portions.

13. The airbag device according to claim 1,

wherein the airbag has a plurality of lines of internal tethers that restrict inflation of the airbag to create a space between the front surface and the third base fabric during inflation of the airbag.

14. The airbag device according to claim 1,

wherein the inside of the airbag is sectioned by a plurality of lines of internal tethers.

15. The airbag device according to claim 1,

wherein the third base fabric has such a length that it is not affected by tension caused by inflation of the airbag during inflation of the airbag.

16. The airbag device according to claim 1,

wherein a fourth base fabric that restricts inflation of the back surface of the airbag in a transverse direction during inflation of the airbag is provided on the back surface base fabric of the airbag.

17. The airbag device according to claim 1,

wherein the airbag device deploys from an opening along a rear end of a bonnet of a vehicle.

6. An airbag device comprising an airbag inflatable with gas generated by an inflator, the airbag having a front surface base fabric and a back surface base fabric,

wherein the front surface base fabric of the airbag has a vent hole through which gas is discharged,

wherein the airbag further has a third base fabric that restricts inflation of the airbag during inflation, the third base fabric covering the vent hole, both sides of the third base fabric being joined to the front surface base fabric, and

wherein, while the airbag is in an inflated state, the third base fabric is broken and the first vent hole is opened, by the further inflation of the airbag resulting from pushing into the third base fabric by a person.

7. The airbag device according to claim 6,

wherein at least one of cut ends of the third base fabric is provided near a boundary between a portion where inflation is restricted by the third base fabric of the airbag when a person pushes into the third base fabric of the airbag in an inflated state, and a portion adjacent thereto where inflation is not restricted.

8. The airbag device according to claim 6,

wherein the third base fabric has a cutting line near the vent hole, and

wherein the third base fabric is cut along the cutting line and the vent hole is opened when a person pushes into the third base fabric of the airbag while the airbag is in an inflated state.

9. The airbag device according to claim 8,

wherein the cutting line includes intermittent cuts.

12. The airbag device according to claim 6,

wherein the front surface base fabric further has a second vent hole provided at a certain distance from the vent hole, the second vent hole being closed by the third base fabric during inflation of the airbag.

10. An airbag device comprising an airbag inflatable with gas generated by an inflator, the airbag having a front surface base fabric and a back surface base fabric,

wherein the front surface base fabric of the airbag has a vent hole through which gas is discharged,

wherein the airbag further has a third base fabric that restricts inflation of the airbag during inflation, the third base fabric covering the vent hole, both sides of the third base fabric being joined to the front surface base fabric, and

wherein, while the airbag is in an inflated state, a joined portion at the joined side portions of the third base fabric is separated and the vent hole is opened, by the further inflation of the airbag resulting from pushing into the third base fabric by a person.

11. The airbag device according to claim 10,

wherein at least one end of the joined side portions of the third base fabric is provided near a boundary between a portion where inflation is restricted by the third base fabric of the airbag when a person pushes into the third base fabric of the airbag in an inflated state, and a portion adjacent thereto where inflation is not restricted.