Abstract: A shock sensor comprises: a piezoelectric element for generating, when pushed, a voltage having a level according to the pushing force; an inertia member held in close contact with the piezoelectric element; and holding means for holding the piezoelectric element and the inertia member in the close contact. The inertia member pushes the piezoelectric element with the pushing force according to a shock, if this shock is applied to the shock sensor, so that the piezoelectric element generates a voltage having a level according to the pushing force.

Abstract: An impact sensing device including an inertia member, an housing for accommodating the inertia member therein and at least three impact sensors disposed in such a manner as to be in contact with an outer peripheral surface of the inertia member, each impact sensor comprising a piezoelectric element for generating a voltage having an amplitude corresponding to an applied stress and an urging member for urging the piezoelectric sensor against the inertia member. Upon application of an impact force to the impact sensor, the inertia member presses the piezoelectric element with a stress corresponding to the impact force to thereby allow the piezoelectric element to generate a voltage corresponding to the applied stress.

Abstract: The present invention provides an impact sensor which has neither electrical contacts exposed to an atmosphere nor any movable components, which is durable and highly reliable, and which is able to safely sense a vehicle impact even if loaded in a vehicle for a considerable period of time. The impact sensor comprises a piezoelectric element (3, 13) for generating a voltage of a magnitude in accordance with a pressure, a pair of electrodes (1c, 1d, 11c, 14) disposed to sandwich the piezoelectric element, an inertial mass (6,16) adapted to apply a pressure to either one of the electrodes, and a biasing member (7, 17) for biasing the inertial mass (6, 16) toward the piezoelectric element (3, 13). When the inertial mass (6, 16) is subject to an impact, the inertial mass (6, 16) is biased to apply to the piezoelectric element (3, 13) a pressure of a level in accordance with the magnitude of the impact.