Gas generator

A gas generator having a housing of which an interior is filled with gas generating agents which generates gas when combusting and a squib stored within the housing for igniting the gas generating agents,

• the housing constructed to accommodate the squib on a proximal portion side and comprising an outer circumferential wall configured to extend from the squib and a ceiling wall adapted to close the outer circumferential wall on a distal end side of the circumferential wall and disposed so as to face the squib, with the gas generating agents filled between the outer circumferential wall lying on a distal end side of the squib and the ceiling wall,
• an outlet hole being formed substantially at a center of the ceiling wall through which combustion gas generated when the squib is activated is allowed to flow out,
• a closure member, which is made able to cut off ventilation between an inside and outside of the housing and breakable when the squib is activated, being disposed so as to close the outlet hole, wherein
• the closure member is thin-walled and is connected to the outer circumferential wall side along a circumferential edge thereof so as to separate the gas generating agents side from the ceiling wall in the interior of the housing, wherein
• thin breakable portions, which are breakable when the squib is activated, are formed in the closure member so as to extend substantially radially from a center thereof in a rectilinear fashion, wherein
• portions of the closure member which lie between the breakable portions are individually made to open as door portions radially about positions in the vicinity of the outer circumferential wall by the breakable portions being broken when the squib is activated, wherein
• a stopper portion is formed on a surface of the ceiling wall which lies on the closure member side so as to restrict the opening of the door portions so that an angle at which the door portions are opened becomes less than 90° while ensuring an angle at which the combustion gas can flow out by the door portions so opened being made to be brought into abutment therewith, wherein
• the closure member includes cup portion made to cover the interior of the housing over substantially the whole area thereof,
• the cup portion includes a substantially cylindrical circumferential portion which is made to extend from the squib so as to cover substantially the whole surface of an inner circumferential side of the outer circumferential wall of the housing, and
• a substantially disc-shaped distal end wall portion which is made to face the squib and to close a distal end of the circumferential wall portion,
• an ignition portion of the squib is inserted to the cup portion and the gas generating agent is accommodated in the cup portion.