Cylindrical filter for pyrotechnic device, manufacturing method for cylindrical filter, and pyrotechnic device using cylindrical filter

A gas generator comprising:

• a housing including a top plate, a circumferential wall, a bottom plate, an upper annular inclined surface extending between the top plate and the circumferential wall, and a lower annular inclined surface extending between the bottom plate and the circumferential wall;
• a cylindrical filter for a gas generating agent or pressurized gas as a gas generation source, the cylindrical filter being provided inside the housing, the cylindrical filter including,
• a first annular end surface;
• a second annular end surface positioned opposite to the first annular end surface in an axial direction;
• a cylindrical wall surface extending between the first annular end surface and the second annular end surface, and
• a weakened portion, integrally formed with a remaining part of the cylindrical filter, and extending from at least one of the first annular end surface and the second annular end surface, wherein
• when the first annular end surface includes the weakened portion, the weakened portion includes a first annular wall portion that protrudes from the first annular end surface and has a thickness less than a thickness of the first annular end surface, the weakened portion is provided such that the weakened portion is bent inward in a radial direction of the housing and an outer peripheral surface of the weakened portion is in contact only with the upper annular inclined surface of the housing and an inner peripheral surface of the weakened portion and a remaining portion of the first annular end surface define a space, and
• when the second annular end surface includes the weakened portion, the weakened portion includes a second annular wall portion that protrudes from the second annular end surface and has a thickness less than a thickness of the second annular end surface, the weakened portion is provided such that the weakened portion is bent inward in the radial direction of the housing and an outer peripheral surface of the weakened portion is in cylindrical contact only with the lower annular inclined surface of the housing and an inner peripheral surface of the weakened portion and a remaining portion of the second annular end surface define a space.