Ventilation component

A ventilation component comprising:

• an internal member including an elastomer, having an open tubular structure, and having a protruding portion protruding outward from an outer circumferential surface of the open tubular structure;
• a gas-permeable membrane covering one opening of the internal member;
• and
• an external member having a closed tubular structure and having a hooking portion on an inner circumferential surface of the closed tubular structure, the hooking portion hooking the protruding portion, wherein
• the internal member is fixed to the external member in a state where the internal member is inserted inside the external member and the external member hooks the protruding portion by the hooking portion,
• the ventilation component is capable of being fixed to a projection of a housing in a state where the projection is inserted inside the internal member through a second opening of the internal member and an inner circumferential surface of the internal member and an outer circumferential surface of the projection abut each other, the projection tubularly protruding from an outer surface of the housing toward an edge of a ventilation opening allowing communication between an inner space and an outer space of the housing,
• in a state where the ventilation component is fixed to the projection, a gas is capable of passing through the gas-permeable membrane for ventilation between the inner space and the outer space of the housing,
• when the internal member and the external member are viewed in plan along an axis of the ventilation component, an outer diameter OB of the protruding portion, an inner diameter IH of the hooking portion, and an inner diameter OO of a portion of the external member satisfy a requirement IH<OB<OO, the portion facing the protruding portion,
• the protruding portion extends along an entire outer circumference of the open tubular structure, and
• the ventilation component allows air to pass from the outer space of the housing to the inner space of the housing in the state where the ventilation component is fixed to the projection.