Curtain airbag for vehicle

1. A curtain airbag for a vehicle, comprising:

a curtain airbag cushion that is deployed between a door window and an occupant;

a venting chamber that is disposed between a front end portion of the curtain airbag cushion and an A pillar of the vehicle, is thicker than the curtain airbag cushion, and fills a space between an end portion of a frontal airbag, the end portion being adjacent to the door window and the A pillar when the venting chamber is deployed;

a first vent opening formed in a portion of the venting chamber, the portion being adjacent to the door window; and

a first tether that is connected between the first vent opening and an inside surface of the venting chamber,

wherein the first tether is loosened and thus the first vent opening is configured to be opened when an external force is applied to a portion of the venting chamber, the portion being connected to the first tether.

2. The curtain airbag for the vehicle according to claim 1 , wherein the first tether is a panel tether and is mounted to extend in a vertical direction in the vehicle.

3. The curtain airbag for the vehicle according to claim 1 , wherein the first vent opening is formed in the venting chamber, in a position that is adjacent to the door window and does not contact with the A pillar.

4. The curtain airbag for the vehicle according to claim 1 , further including a second vent opening through which the curtain airbag cushion and the venting chamber communicate with each other.

5. The curtain airbag for the vehicle according to claim 4 , wherein the second vent opening is a vent opening that is configured to be opened or closed under control.

6. The curtain airbag for the vehicle according to claim 4 , further including:

a first tether cutter;

a cover for opening or closing the second vent opening; and

a second tether that is connected between the cover and the first tether cutter,

wherein the second vent opening continues open for a first predetermined time and is then closed by the cover when the second tether is cut by the first tether cutter.

7. The curtain airbag for the vehicle according to claim 1 , further including a third tether that is connected between a center portion of the first tether and a portion of the inside surface of the venting chamber,

wherein an angle between fractions of the first tether disposed on a first side and a second side of a position at which the first tether and the third tether are connected to each other is an obtuse angle and wherein an angle between a portion of the first tether, the portion being adjacent to the first bent opening, and the third tether is an obtuse angle.