Nippondenso Co., Ltd.

Hideki Miyazawa

Masaru Suzuki

Yoshihisa Nakano

Kazuma Matsui

Akio Tanaka

Fumiaki Murakami

Tetsuya Nagata

Yutaka Ohasi

A pressure sensor includes a diaphragm having a magnetic film fixed to one side thereof. The diaphragm is arranged to displace depending on a pressure differential applied thereacross to change an inductance of a coil which is arranged close to the magnetic film with a predetermined gap therebetween. An alternating current is supplied to the coil to be modulated by the inductance of the coil so that the pressure differential across the diaphragm is converted into an electric signal. A monitored pressure is derived based on this converted electric signal.

Pressure sensor using a pressure responsive magnetic film to vary

A tire pressure detecting portion includes a housing, provided within the tire, within which a piezoelectric element is provided so as to be deformed by the tire pressure. The capacitance of said piezoelectric element is changed in accordance with its deformation. The piezoelectric element is electrically connected with a first coil diposed within said tire. The first coil is electromagnetically coupled with an excitation coil and a receiving coil, both of which are provided in the vehicle. The excitation coil provides an excitation voltage whole frequency is changed within a predetermined range including a resonant frequency. When the received voltage has the resonant frequency, a correspondinq tire pressure is determined based on a data map showing the relationship between said resonant frequency and the tire pressure.

Tire pressure detecting apparatus for vehicle

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Kariya, Japan

Hideki Miyazawa