Patent ID: 7648163

Claim:
A gas generator for an air bag, comprising: a housing having a gas discharge port; an inner cylinder provided inside the housing and defining therein an ignition means chamber, in which ignition means are accommodated, and a combustion chamber, in which a gas generating agent is accommodated, and separated from the ignition means chamber, the inner cylinder being provided with a first through hole that allows only the ignition means chamber to communicate with a chamber outside the inner cylinder, and a second through hole that allows only the combustion chamber to communicate with the chamber outside the inner cylinder; a cylindrical coolant/filter disposed within the chamber outside the inner cylinder, and between the combustion chamber and the gas discharge port so that combustion gas passes through the coolant/filter prior to discharge through the gas discharge port, a retainer including a lower peripheral wall, an upper peripheral wall, and an annular plane connecting the lower peripheral wall and the upper peripheral wall, the retainer being provided such that, the lower peripheral wall opposes the first through hole and makes a direct contact with an inner circumferential wall extending between a ceiling surface and a base surface of the housing, the annular plane supporting a lower end surface of the cylindrical coolant/filter, and the upper peripheral wall opposes the second through hole and the gas discharge port, wherein a first gap is defined between the cylindrical coolant/filter and the upper peripheral wall, and a second gap is defined between the cylindrical coolant/filter and the inner circumferential wall of the housing, the first gap and the second gap are provided between the upper peripheral wall and the gas discharge port.