Tire internal pressure alarm device

摘要

An elastic member 11 positioned between an inner surface of a casing 2 and a front face of a pressure sensing portion 8 of a pressure sensor 1 reduces a possibility of liquid and foreign matters in a tire directly reaching the pressure sensing portion 8. The elastic member also increases adhesiveness between the pressure sensing portion 8 of the pressure sensor 1 and a labyrinth structure and further prevents a potting agent 9b from flowing into the sensing portion 8. Moreover, the elastic member 11 is a member constituting at least a part of the labyrinth structure, so that it does not need that a wall is provided on the pressure sensor 1 and a dedicated seal member is provided on the pressure sensing portion 8.