Patent ID: 8667897

Claim:
A gas generator comprising: a main housing accommodating at least one of a gas and a gas generating means for generating a gas; a diffuser portion connected to the main housing and discharging a gas located inside the main housing or a gas generated inside the main housing, the diffuser portion having a cup-like shape and including an opening portion joined to the main housing and a circumferential wall portion provided with a plurality of gas discharge ports; a partition plate fixedly attached to an annular portion on a side of the opening portion and closing the opening portion, an inside of the diffuser portion having a first tubular space portion and a second tubular space portion communicating with each other, the first tubular space portion facing the partition plate, and the second tubular space portion communicating with the gas discharge ports, the first tubular space portion and the second tubular space portion being communicated with each other and provided with a step such that an inner diameter d1 of the first tubular space portion and an inner diameter d2 of the second tubular space portion satisfy a relationship d1>d2, a cross-sectional area a1 of the second tubular space portion having the inner diameter d2 is set to be smaller than a total opening area a2 of the gas discharge ports, and the opening portion being defined by a curved surface, such that when the partition plate is petal-like cleaved during actuation of the gas generator, the curved surface prevents that partition plate from breaking away.