Patent ID: 7578522

Claim:
A gas generator comprising: a housing formed by a closure shell and a diffuser shell having a gas discharge port, a combustion chamber provided inside the housing and charged with a gas generating agent, an ignition device to ignite and burn the gas generating agent inside the combustion chamber, a cylindrical filter disposed to face the gas discharge port and having an annular upper surface press-contacting a ceiling surface of the housing, a retainer disposed inside the combustion chamber to support the cylindrical filter and the retainer being substantially a cylinder, having a larger diameter portion and a smaller diameter portion, that is provided with a vent hole, and an annular surface portion provided between the larger diameter portion and the smaller diameter portion, an outer peripheral surface of the larger diameter portion abutting against an inner wall surface of the housing before activation and press-contacting the inner wall surface of the housing in activation, the annular surface portion press-contacting an annular lower surface of the cylindrical filter, an outer peripheral surface of the smaller diameter portion abutting against an inner peripheral surface of the cylindrical filter, a lower end portion of the larger diameter portion press-contacting the inner peripheral surface of the housing, a lower end portion of the larger diameter portion having an inward-facing flange portion, an upper end portion of the smaller diameter portion having an inward-facing flange portion, and the flange portion of the larger diameter portion press-contacting a bottom surface of the closure shell.