Safety airbag device, vehicle seat and vehicle

A safety airbag device adapted to be mounted on a seat of a vehicle, wherein the safety airbag device comprises a head airbag portion, a chest airbag portion, an airbag tensioning belt and an airbag tensioner;

• wherein the head airbag portion is disposed around an upper edge and left and right edges of a backrest of the seat, so that the head airbag portion is capable of surrounding a head of the occupant from the left and right sides and from above after deployment and covers at least side areas of the head of an occupant after deployment, and the head airbag portion has an asymmetric structure about a central axis of the seat, wherein a first side of the head airbag portion extends from a top portion of the backrest of the seat to a position near a shoulder portion of the occupant, and a second side of the head airbag portion extends from the top portion of the backrest of the seat to a bottom portion of the backrest of the seat, such that the first side of the head airbag portion extends at a length shorter than that extended by the second side of the head airbag portion, whereby a space for accommodating a second safety airbag device is reserved at the first side of the head airbag portion, wherein the first side of the head airbag portion is a side close to a door of the vehicle, and the second side of the head airbag portion is a side away from the door of the vehicle;
• and
• wherein one end of the chest airbag portion is connected to one of the first side and the second side of the head airbag portion, and other end of the chest airbag portion is connected with the airbag tensioner via the airbag tensioning belt, when the one end of the chest airbag portion is connected to the second side of the head airbag portion, the airbag tensioner is disposed on a side of the seat close to the door of the vehicle, and when the one end of the chest airbag portion is connected to the first side of the head airbag portion, the airbag tensioner is disposed on a side of the seat away from the door of the vehicle, and wherein the chest airbag portion is configured to bring the airbag tensioning belt to pass over the head of the occupant and reach a position in front of a chest of the occupant during deployment, and the airbag tensioner is configured to pull the chest airbag portion to the position in front of the chest of the occupant by tensioning the airbag tensioning belt to at least protect a chest area of the occupant.