Patent ID: 7673899

Claim:
An airbag capable of being inflated by gas from a gas generator, the airbag comprising: a front panel arranged on a passenger side; a rear panel arranged on an opposite side from the passenger side, the front panel and the rear panel being connected to each other along peripheral edge portions thereof; a port for the gas generator provided at a center of the rear panel; a columnar inner panel, securely fixed to the front panel and the rear panel so as not to break, for dividing an interior of the airbag into a first chamber at a center extending between the front panel and the rear panel when the airbag is fully inflated, and a second chamber which surrounds the first chamber, said inner panel having a communication hole for allowing gas to flow from the first chamber to the second chamber; and a low-strength connecting device for connecting a part of the inner panel together without connecting to the front and rear panels so that the communication hole is closed and capacity of the first chamber is reduced, said low-strength connecting device maintaining the connection so as to maintain the capacity of the first chamber at a relatively small first capacity until a gas pressure in the first chamber reaches a predetermined pressure, and releasing the connection when the gas pressure in the first chamber exceeds a predetermined pressure so as to make the capacity of the first chamber a second capacity larger than the first capacity and allow the gas to flow from the first chamber to the second chamber through the communication hole while limiting a position of the front panel relative to the rear panel by the columnar inner panel, wherein the inner panel connects the front and rear panels when the airbag is inflated more than the predetermined pressure and the low-strength connecting device releases the connection.