Inflation pressure sensor for automobile pneumatic tire

摘要

A tire inflation pressure sensor mounted on the outside of the wheel. The sensor housing includes a diaphragm, a cylinder, a magnet holder, a spring, a magnet holding member connected with a magnet, a guide member and a stopper. When the inflation pressure of a tire is normal, the magnet holding member stops at a position where the magnet indicates a north pole. When the inflation pressure goes down below a specified value, the magnet holding member travels a predetermined distance and at the same time the magnet holding member rotates at a predetermined angle indicating a south pole. This changeover of magnetic polarity is detected by an external magnetic induction element to operate a warning device.