Gas generator

A gas generator, comprising:

• a cylindrical ignition device chamber housing provided with a gas discharge port, and accommodating therein an igniter and a gas generating agent, the igniter closing an opening portion of the ignition device chamber housing and being fixed thereto;
• a cylindrical pressurized gas chamber housing filled with pressurized gas, and being joined to the cylindrical ignition device chamber housing to form an outer-shell container;
• a closing member closing a boundary surface between the ignition device chamber housing and the pressurized gas chamber housing;
• a multifunctional member, movable in an axial direction during activation, being disposed inside the ignition device chamber housing together with the igniter and the gas generating agent, the multifunctional member having,
• a base plate portion, and
• a cylindrical wall portion extending from one surface of the base plate portion, an annular end surface of an opening portion of the cylindrical wall portion including an inclined end surface inclined with respect to the base plate portion, the multifunctional member being provided such that the inclined end surface is not in contact with the closing member,
• the multifunction member moving in the axial direction by internal pressure increase due to combustion gas generated by combustion of the gas generating agent to break the closing member with the inclined end surface of the cylindrical wall portion, and thereby, obtaining a gas discharge path;
• a plenum chamber being enclosed by the ignition device chamber housing, the base plate portion and the closing member, and being provided such that the gas discharge port is formed in a circumferential wall portion of the ignition device chamber housing facing the plenum chamber;
• a gas generating agent charging chamber charged with the gas generating agent, enclosed by the base plate portion, the igniter and an inner wall surface of the ignition device chamber housing, the gas generating agent charging chamber and the plenum chamber communicating with each other;
• and
• a movement restriction means restricting a moving distance in the axial direction of the multifunctional member before and after activation such that a longest portion of the cylindrical wall portion passes through the closing member but a shortest portion of the cylindrical wall portion does not pass through the closing member.