A side airbag is disposed at a side of a seat of a vehicle and inflated with gas supplied from a gas generator. The side airbag includes a sub-bag disposed in a lower section of the side airbag to be inflated with the gas supplied from the gas generator, and an upper section of the side airbag is inflated with the gas from the sub-bag.
1. A side airbag disposed in a vehicle to be inflated with gas from a gas generator, comprising:
a main bag member having a lower section and an upper section, and
a sub-bag disposed at the lower section of the main bag member to be connected to the gas generator and having an upwardly extending portion extending upwardly from one side of the sub-bag to be located in and surrounded by the upper section to allow the gas generator to be disposed therein so that the sub-bag is inflated with the gas from the gas generator and the upper section of the main bag is inflated with the gas from the sub-bag.
2. A side airbag according to claim 1 , wherein said sub-bag has an opening so that the sub-bag is inflated first with the gas from the gas generator and then the upper section of the main bag is inflated when the gas from the sub-bag enters through the opening.
3. A side airbag according to claim 2 , further comprising closing means disposed in the main bag for blocking the opening of the sub-bag, said closing means opening the opening when a gas pressure in the sub-bag reaches a predetermined pressure so as to allow the gas to flow out from the sub-bag.
4. A side airbag according to claim 2 , wherein said opening is located at a side away from the upwardly extending portion and disposed below the upwardly extending portion.
5. A side airbag according to claim 4 , wherein said upwardly extending portion is located at a side close to a back of a seat to allow the gas generator to be located vertically.
6. A side airbag according to claim 1 , wherein said sub-bag is inflated at a maximum pressure of about 300 KPa and said upper section is inflated at a maximum pressure of about 100 KPa.
7. A side airbag apparatus comprising the side airbag according to claim 1 , and a gas generator.