Curtain airbag device for vehicle

1. A curtain airbag device for a vehicle, the curtain airbag device comprising:

a curtain airbag configured to inflate and deploy toward a vehicle lower side from an outer side end portion of a ceiling of the vehicle in a vehicle width direction, when an inflator activates at a time of vehicle collision and supplies gas into the curtain airbag, the curtain airbag including a leading end chamber provided at a vehicle front side of the curtain airbag, a lower end portion of the leading end chamber being disposed at a vehicle lower side relative to a belt line at a time of inflation and deployment of the curtain airbag; and

a restraint performance improvement portion provided at a portion of a lower end portion of the curtain airbag that corresponds to a vehicle seat in a comfortable state in which a seat back of the vehicle seat is tilted toward a vehicle rear side by at least a predetermined angle in a vehicle side view, the curtain airbag producing a reaction force at the time of inflation and deployment from a region at which the leading end chamber is disposed at the vehicle lower side relative to the belt line, and the restraint performance improvement portion configured to prevent a head area of a vehicle occupant from moving past the curtain airbag toward an outer side of the curtain airbag in the vehicle width direction during restraint of the vehicle occupant, wherein:

a first end portion of a strap that is attached to the leading end chamber is attached to a lower end portion of the restraint performance improvement portion, the first end portion, at the vehicle rear side, of the strap is attached to a central portion, in a vehicle front-rear direction, of a region between (i) a region of the curtain airbag that overlaps with a center pillar garnish in a vehicle side view at the time of inflation and deployment, and (ii) the leading end chamber; and

a second end portion, at the vehicle front side, of the strap is attached to a strap front end attachment portion that, at the time of inflation and deployment, is disposed at the vehicle lower side of an end portion, at the vehicle rear side, of the leading end chamber.

2. The curtain airbag device for the vehicle according to claim 1 , wherein the restraint performance improvement portion is configured as a separate base fabric attached to a face of the curtain airbag at a vehicle cabin interior side of the curtain airbag, and a friction force of the separate base fabric is greater than the friction force of the inner side face in the vehicle width direction at the portions of the curtain airbag other than the restraint performance improvement portion.

3. The curtain airbag device for the vehicle according to claim 1 , wherein the restraint performance improvement portion is configured as a coating applied to a face of the curtain airbag at a vehicle cabin interior side of the curtain airbag, the coating providing a greater friction force than the friction force of the inner side face in the vehicle width direction at the portions of the curtain airbag other than the restraint performance improvement portion.

4. The curtain airbag device for the vehicle according to claim 1 , wherein the restraint performance improvement portion includes stitching at a face of the curtain airbag at a vehicle cabin interior side of the restraint performance improvement portion.

5. The curtain airbag device for the vehicle according to claim 1 , wherein the second end portion, at the vehicle front side, of the strap is attached to the leading end chamber in a state in which the leading end chamber of the curtain airbag is folded over toward a vehicle upper side, when the curtain airbag is unfolded into a flat state.

6. The curtain airbag device for the vehicle according to claim 1 , wherein:

a first end portion of a tension belt is fixed to a front pillar; and

a second end portion of the tension belt is attached to a vehicle lower side of an end portion, at a vehicle front side, of the leading end chamber.