Drive system of actuator having piezoelectric device for use in motor vehicle

Abstract

A drive system of a piezo-type actuator for use in a motor vehicle, which piezo-type actuator is constructed with a piezoelectric device which is expandable and contractible in accordance with application of a voltage thereto. The drive system includes a voltage-increasing section for increasing an output voltage of a power source mounted on the motor vehicle so as to develop a drive voltage for the piezo-type actuator and a voltage-application section for applying to the piezoelectric device of the piezo-type actuator the drive voltage. Also included in the drive system is an abnormality detection section which is arranged so as to an abnormality of the drive voltage developed by the voltage-increasing section. A safety controller is responsive to an abnormality signal from the abnormality detection section for prohibiting the application of the drive voltage to the piezoelectric device thereof and further discharging charges accumulated in the piezoelectric device thereof when the abnormality detection section detects the abnormality of the developed drive voltage. With this arrangement, it is possible to prevent troubles due to the abnormality of the drive voltage to be applied to the piezoelectric device of the piezo-type actuator.

Dependencies are inferred from the claim text.