JPS6475919A - Acceleration sensor - Google Patents

Abstract

PURPOSE:To obtain a sensor, from which voltage is hardly outputted even if temperature is changed, by fixing piezoelectric ceramics to a metal diaphragm, whose central part is fixed, constituting a vibrator, and providing an additional mass to the metal diaphragm. CONSTITUTION:A cabinet 1 and a base 2 are vibrated by acceleration, which is applied to a vehicle and the like. A metal diaphragm 4 and piezoelectric ceramics 5, which is fixed to the diaphragm 4, are deflected in proportion to the applied acceleration accompanied by the vibration. Since a load mass 9 is provided on the diaphragm 4, the deflecting amount becomes 3-10 times. The electric charge in the ceramics 5 is changed in proportion to the deflecting amount. The change is transduced into the change in voltage in an impedance transducer circuit 6. A voltage is obtained at an output terminal 8 through a filtering and amplifying circuit 7. Since the amount of the electric charge in the ceramics 5 is changed, the amplitude of the circuit 7 can be reduced. The proelectric effect of the ceramics 5 can be reduced substantially by that amount.