Patent ID: 7252303

Claim:
An inflator, comprising: an inflator housing accommodating a pressurized medium and defining an opening; a diffuser portion that covers the opening and is provided with at least one gas discharging port, formed in a peripheral wall of the diffuser portion, for discharging the pressurized medium upon actuation of the inflator, such that pressure inside the diffuser portion is at an atmospheric pressure prior to an activation of the inflator; the diffuser portion defining therein a flow-path that allows the pressurized medium to flow from the inflator housing to the at least one gas discharging port; a rupturable plate that seals the flow-path, a peripheral portion of the rupturable plate being attached to the diffuser portion and an entire remaining portion of the rupturable plate being apart from any of elements of the inflator; rupturing means, that directly opposes the rupturable plate, for rupturing the rupturable plate; and a filter that covers the at least one gas discharging port, such that the pressurized medium is discharged from the at least one gas discharging port through the filter, wherein, at least one selected among the following requirements (a), (b), and (c) is provided, (a): the pressurized medium filled in the inflator housing has a sound velocity of not less than 400 m/sec at 0° C. at 1013.25 hPa, (b): a charging pressure at 20° C. of the pressurized medium in the inflator housing is not less than 40,000 kPa, and (c): the total area (A 1 ) of the gas discharging port(s) and the area (A 2 ) of the opening is set to meet A 1 /A 2 ≦1, wherein the pressurized medium is discharged through the diffuser portion without being heated.