Patent ID: 7409868

Claim:
A load detecting device comprising: a sensor element arranged on a supporting member to effect both vibration-generation and vibration-detection, the sensor element including only one piezoelectric member, and first and second electrodes on opposite surfaces of the only one piezoelectric member, respectively, the sensor element converting a load or an acceleration applied to the supporting member into a detection signal; a driving portion for outputting a driving signal for vibrating the sensor element; a vibration detecting portion for extracting the detection signal from the sensor element and for detecting a vibration characteristic value of the sensor element based on the detection signal extracted; a wiring for electrically connecting the sensor element, the driving portion and the vibration detecting portion to one another, and for transmitting a superimposed signal constituted by superposition of the driving signal from the driving portion and the detection signal from the sensor element; and a calculating portion for calculating one of or both of a load and an acceleration applied to the sensor element based on the vibration characteristic value from the vibration detecting portion.