Airbag device

1. An airbag device having a hollow airbag which constrains an occupant by being deployed by gas supplied by an inflator, and which includes a first face-constituting base fabric facing a side of the occupant, and a second face-constituting base fabric facing a side opposite to the occupant,

the airbag comprising:

a vent hole which is provided in the second face-constituting base fabric, for discharging the gas;

a slide tether which is provided from an inner surface of the second face-constituting base fabric to an inner surface of the first face-constituting base fabric, and which performs transition of a state of the vent hole, from an open state via a close state to the open state, by changing between a slackened state and an extended state;

a slide tether cover which is provided with an opening communicated with the vent hole, one end of which is fastened to the inner surface of the second face-constituting base fabric at an inner peripheral side of the vent hole via a body portion of the slide tether, the other end of which is fastened to the inner surface of the second face-constituting base fabric at an outer peripheral side of the vent hole, and which guides the slide tether; and

a joint capable of being separated by a predetermined pressure of the gas and formed in the first face-constituting base fabric and the second face-constituting base fabric, both in the outer peripheral side of the vent hole,

wherein the slide tether includes the body portion, bifurcated portions which are bifurcated from one end portion in a longitudinal direction of the body portion, and leg piece portions which are respectively extended from the bifurcated portions,

wherein the other end portion in the longitudinal direction of the body portion constitutes a first supporting point by being fastened to an inner surface of the second face-constituting base fabric in a direction going from the vent hole toward a mounting position of the inflator,

wherein the bifurcated portions constitute a second supporting point by the other end portion of the slide tether cover being fastened to the inner surface of the second face-constituting base fabric,

wherein extended terminal end portions of the leg piece portions constitute a third supporting point by being respectively fastened to the inner surface of the first face-constituting base fabric, and

wherein, when the airbag is deployed, transition of a state of the vent hole is performed based on a force acting in an airbag deploying direction which is generated with the first supporting point and the third supporting point as a starting point, and a force acting, in a direction going from a center portion of the airbag toward an outer peripheral portion of the airbag and intersecting with the airbag deploying direction, which is generated with the second supporting point as a starting point.

2. The airbag device according to claim 1 , wherein the vent hole is provided near an insertion hole of the inflator.

3. An airbag device having a hollow airbag which constrains an occupant by being deployed by gas supplied by an inflator, and which includes a first face-constituting base fabric facing a side of the occupant, and a second face-constituting base fabric facing a side opposite to the occupant, the airbag device comprising:

a vent hole which is provided in the second face-constituting base fabric, for discharging the gas;

a slide tether which is provided from an inner surface of the second face-constituting base fabric to an inner surface of the first face-constituting base fabric, and which performs transition of a state of the vent hole, from an open state via a close state to the open state, by changing between a slackened state and an extended state;

a stopper piece which is arranged on the slide tether and restricts backward motion of the slide tether toward the vent hole; and

a slide tether cover which is provided with an opening communicated with the vent hole, one end of which is fastened to the inner surface of the second face-constituting base fabric, and which guides the slide tether,

wherein the slide tether includes a body portion, bifurcated portions which are bifurcated from one end portion in a longitudinal direction of the body portion, and leg piece portions which are respectively extended from the bifurcated portions,

wherein the other end portion in the longitudinal direction of the body portion constitutes a first supporting point by being fastened to an inner surface of the second face-constituting base fabric in a direction going from the vent hole toward a mounting position of the inflator,

wherein the bifurcated portions constitute a second supporting point by the other end portion of the slide tether cover being fastened to the inner surface of the second face-constituting base fabric,

wherein extended terminal end portions of the leg piece portions constitute a third supporting point by being respectively fastened to the inner surface of the first face-constituting base fabric, and

wherein, when the airbag is deployed, transition of a state of the vent hole is performed based on a force acting in an airbag deploying direction which is generated with the first supporting point and the third supporting point as a starting point, and a force acting, in a direction intersecting with the airbag deploying direction, which is generated with the second supporting point as a starting point.