Vehicle occupant protecting device

1. A vehicle occupant protecting device comprising:

an airbag that is accommodated in a headrest or a seatback, that receives a gas supply from an inflator and inflates and expands, that protects a head portion of a vehicle occupant from at least a front side and left and right both sides, and at which a front expanding portion, which protects the head portion from a front side, passes above the head portion in a process of inflating and expanding; and

a vehicle cabin ceiling at which an expanding direction regulating section is provided at an interference region which the airbag interferes with in the process of inflating and expanding, and that, by the interference, directs an expanding direction of the front expanding portion toward a front side of the head portion,

wherein the airbag is structured as an integral bag body, and

wherein the expanding direction regulating section comprises a reinforcing portion that is disposed within the vehicle cabin ceiling, that reinforces the interference region with respect to a load from a lower side, and that increases the reaction force which the airbag that interferes with the interference region receives from the interference region.

2. The vehicle occupant protecting device of claim 1 , wherein the expanding direction regulating section has an inclined surface that is inclined downward while heading in a vehicle forward direction or a vehicle rearward direction, and the airbag that is in the process of inflating and expanding interferes with the inclined surface.

3. The vehicle occupant protecting device of claim 2 , wherein, at the vehicle cabin ceiling, an installation portion in which an air conditioner or a sunroof device is installed, bulges out toward a lower side, and an end surface at a vehicle rear side of the installation portion is the inclined surface.

4. The vehicle occupant protecting device of claim 1 , wherein the expanding direction regulating section has

an interfering member for interfering with the airbag that is in the process of inflating and expanding, and

a drive source that is operated at a time when the inflator is operated, and that moves the interfering member from an interior of the vehicle cabin ceiling toward an interior of a vehicle cabin.

5. The vehicle occupant protecting device of claim 1 , wherein

the vehicle cabin ceiling has a roof head lining that is an interior material, and

the expanding direction regulating section is a plurality of reinforcing portions that are provided at an upper surface of the roof head lining so as to be lined up at least in a vehicle longitudinal direction among the vehicle longitudinal direction and a vehicle transverse direction, and that reinforce the roof head lining.

6. The vehicle occupant protecting device of claim 1 , wherein

the airbag includes:

a pair of left and right frame ducts that inflate and expand with an interval therebetween at regions that include the left and right both sides and the upper side with respect to the head portion,

a front expanding portion that protects the head portion from the front,

a pair of lateral expanding portions that protect the head portion from the left and right both sides, and

an upper expanding portion that protects the head portion from the upper side; and

the pair of left and right frame ducts are configured to guide gas from the inflator to the front expanding portion, the pair of lateral expanding portions, and the upper expanding portion.