Curtain airbag

1. A curtain airbag device having an airbag that is disposed along a roof side rail of a vehicle interior, and the curtain airbag adapted to deploy so as to cover a window portion on a side face of the vehicle interior,

the curtain airbag device comprising,

a cover that covers the airbag, at least in a part of the airbag in a folded or rolled condition in the longitudinal direction, wherein

the cover is formed of a pliable fabric material having a plurality of polymer fibers, and is configured to maintain the shape of the airbag in the folded or rolled condition through a mutual fusion of at least a part of the polymer fibers;

the cover has a high stiffness portion of the cover harder than other portions of the cover, and the high stiffness portion is formed during the fusion of the cover, extends in the longitudinal direction of the cover, and is formed by superimposed portions of the cover; and

the high stiffness portion defines a mark that is formed by providing a recess or a projection by partial deformation of the cover and allows a twisted state of the airbag in the folded or rolled condition to be recognized.

2. The curtain airbag device according to claim 1 , further comprising, the cover is provided by being divided at a plurality of parts in the longitudinal direction of the airbag in the folded or rolled condition.

3. The curtain airbag device according to claim 2 , further comprising, the mark is formed in the vicinity of an end section of the cover of at least one of the plurality of parts.

4. The curtain airbag device according to claim 1 , further comprising, the mark is a line-like groove or a rib formed in the longitudinal direction of the airbag, and on a surface of the cover.

5. The curtain airbag device according to claim 1 , further comprising, the mark is formed in the longitudinal direction of the airbag, on a surface of the cover, and constitutes a tearing part during an inflation and deployment of the airbag.

6. The curtain airbag device according to claim 1 , further comprising,

a base fabric extension portion that extends from the airbag is provided on an upper edge of the airbag;

an attachment for attaching the airbag to the vehicle interior is connected to the base fabric extension portion; and

at least a part of the base fabric extension portion is covered by the cover.

7. The curtain airbag device according to claim 6 , further comprising, the base fabric extension portion is provided in the vicinity of the high stiffness portion.

8. The curtain airbag device according to claim 6 , further comprising, the base fabric extension portion is continuously integrated with a base fabric of the airbag.

9. The curtain airbag device according to claim 6 , further comprising, the base fabric extension portion is provided separately from a base fabric of the airbag.

10. The curtain airbag device according to claim 6 , further comprising, the base fabric extension portion has an outer portion that extends outside the cover through a slit provided in the cover.

11. The curtain airbag device according to claim 10 , further comprising, the cover is provided with a plurality of the slits, through which the base fabric extension portion passes a plurality of times.

12. The curtain airbag device according to claim 6 , further comprising, the attachment is folded back in a body part direction of the airbag, and is connected by sewing, along with the cover and the base fabric extension portion inside the cover.

13. The curtain airbag device according to claim 6 , further comprising, the attachment is connected to the base fabric extension portion.

14. The curtain airbag device according to claim 13 , further comprising, the attachment includes a bracket that connects the base fabric extension portion and a fixing member for fixing to the vehicle.

15. The curtain airbag device according to claim 6 , further comprising,

the entirety of the base fabric extension portion is covered by the cover; and

the attachment is provided on the outside of the cover, and is connected by sewing, along with the cover and the base fabric extension portion inside the cover.

16. The curtain airbag device according to claim 15 , further comprising, the attachment is made up of a band-like fabric, and connects, to the band-like fabric, a fixing member for fixing to the vehicle.

17. The curtain airbag device according to claim 15 , further comprising,

the attachment is provided with a band-like fabric member in which a band-like fabric is formed in a loop-like shape, a fixing member for fixing to the vehicle, and a bracket connected between the fixing member and the band-like fabric member, and a loop of the band-like fabric member is connected to a part of the bracket.

18. The curtain airbag device according to claim 6 , further comprising,

the entirety of the base fabric extension portion is covered by the cover;

the base fabric extension portion is connected to the attachment inside the cover;

a part of the attachment is provided so as to be exposed to the outside of the cover; and

the cover and the base fabric extension portion inside the cover are connected by sewing.

19. The curtain airbag device according to claim 18 , further comprising, the attachment is made up of a clip or a bolt that can be attached to a vehicle body.

20. The curtain airbag device according to claim 18 , further comprising, a part of the cover member is configured to be interposed between the attachment and a body of the airbag.

21. The curtain airbag device according to claim 18 , further comprising, inside the cover, the base fabric extension portion is folded back in a direction opposite a direction in which the airbag is folded up or rolled in the folded or rolled condition, and a part of the cover member wound beforehand is provided interposed between the attachment and a body of the airbag.

22. The curtain airbag device according to claim 18 , further comprising, the attachment is provided with a fixing member for fixing to the vehicle, and with a bracket for connecting the fixing member and the base fabric extension portion, and a part of the bracket is provided so as to be exposed to the outside of the cover.

23. The curtain airbag device according to claim 1 , further comprising, the pliable fabric material is a nonwoven fabric.

24. The curtain airbag device according to claim 1 , wherein the plurality of polymer fibers comprises a plurality of bi-component composite fibers with a core and a sheath, such that the shape of the airbag is stabilized through fusion of the sheaths of the bi-component composite fibers to one another.

25. The curtain airbag device according to claim 24 , further comprising,

the core of the bi-component composite fibers is formed of a polymer material having a first melting point; and

the sheath of the bi-component composite fibers is configured by comprising a polymer material having a second melting point lower than the first melting point.

26. The curtain airbag device according to claim 24 , further comprising, the plurality of polymer fibers comprise a plurality of mono-component fibers.

27. The curtain airbag device according to claim 25 , further comprising,

the plurality of polymer fibers comprise a plurality of mono-component fibers; and

the mono-component fibers have a melting point higher than the melting point of the sheath of the bi-component composite fibers.

28. The curtain airbag device according to claim 25 , further comprising, the core of the bi-component composite fibers is formed of a PET homopolymer, and the sheath is formed of a PET copolymer.

29. The curtain airbag device according to claim 25 , further comprising, the mono-component fibers are formed of PET.