Abstract: The frequency of a drive signal supplied to a piezoelectric actuator 91 is swept within a specific range, the consumption current of the piezoelectric actuator 91 is determined, and when the consumption current is equal to or greater than a reference value, the frequency of the drive signal supplied to the piezoelectric actuator 91 is shifted proportionate to a specific frequency and returned to its initial value, and the frequency sweep is continued. The resonance frequency component can be removed when the frequency of the drive signal supplied to the piezoelectric element is swept. Consequently, the piezoelectric element can be driven outside of the resonance frequency range at which the consumption current is highest, allowing extreme increases in the consumption current to be prevented and system failures due to the flow of an excessive consumption current to be avoided.

Abstract: A generally diamond-shaped detection electrode is formed in the approximate center of the piezoelectric element. The strain resulting from the bending secondary vibration mode in the vicinity of the detection electrode is minimized because the detection electrode is formed in such a manner as to include a vibrational node of the longitudinal primary vibrational mode and a vibrational node of the bending secondary vibrational mode. As a result when the phase difference between the drive signal and the detection signal is detected, the effect of vibration in the bending secondary vibration mode on the detected phase difference can be suppressed and a single drive frequency can be determined with respect to a prescribed phase difference. Thus, the drive performance of the vibrating body with respect to a driven body (i.e.

Abstract: A frequency of a drive signal supplied to a piezoelectric element is swept within a specific range, a detection signal indicating the vibrating state of a vibrating member is detected, and the sweep speed of the drive signal frequency supplied to the piezoelectric element is controlled based on this detection signal. Thus, even if nonuniformities occur in the drive frequency of the piezoelectric element due to fluctuations in the surrounding temperature or the load, such nonuniformities can be overcome without any adjustments, and the piezoelectric element can be reliably driven. Also, since the sweep speed of the drive signal frequency is at a high speed when the vibrating member is in a non-drive state, needless drive signal output time during which the piezoelectric element cannot be driven can be reduced, needless power consumption can be curtailed, and nonuniformities in the drive speed of the driven object can also be reduced.

Abstract: Detection electrodes 82D and 82E are formed at positions that include an antinode of a flexural oscillation mode. The strain of flexural oscillation reaches a maximum and the effects on the phase difference in the longitudinal oscillation mode can be cancelled out. The detection electrodes 82D and 82E are formed at the positions of drive electrodes 82B and 82C used to excite the flexural oscillation mode. A phase difference in the flexural oscillation mode opposite in sign relative to the longitudinal oscillation mode is created making it is easy to classify based on the phase difference between a frequency at which the longitudinal oscillation mode is dominant and a frequency at which the flexural oscillation mode is dominant. Thus, reliable control can be achieved based on the oscillation behaviors at each frequency ensuring a satisfactory drive force based on oscillation in the longitudinal oscillation mode.

Abstract: The frequency of a drive signal supplied to a piezoelectric actuator 91 is swept within a specific range, the consumption current of the piezoelectric actuator 91 is determined, and when the consumption current is equal to or greater than a reference value, the frequency of the drive signal supplied to the piezoelectric actuator 91 is shifted proportionate to a specific frequency and returned to its initial value, and the frequency sweep is continued. The resonance frequency component can be removed when the frequency of the drive signal supplied to the piezoelectric element is swept. Consequently, the piezoelectric element can be driven outside of the resonance frequency range at which the consumption current is highest, allowing extreme increases in the consumption current to be prevented and system failures due to the flow of an excessive consumption current to be avoided.

Abstract: A frequency of a drive signal supplied to a piezoelectric element is swept within a specific range, a detection signal indicating the vibrating state of a vibrating member is detected, and the sweep speed of the drive signal frequency supplied to the piezoelectric element is controlled based on this detection signal. Thus, even if nonuniformities occur in the drive frequency of the piezoelectric element due to fluctuations in the surrounding temperature or the load, such nonuniformities can be overcome without any adjustments, and the piezoelectric element can be reliably driven. Also, since the sweep speed of the drive signal frequency is at a high speed when the vibrating member is in a non-drive state, needless drive signal output time during which the piezoelectric element cannot be driven can be reduced, needless power consumption can be curtailed, and nonuniformities in the drive speed of the driven object can also be reduced.

Abstract: Detection electrodes 82D and 82E are formed at positions that include an antinode of a flexural oscillation mode. The strain of flexural oscillation reaches a maximum and the effects on the phase difference in the longitudinal oscillation mode can be cancelled out. The detection electrodes 82D and 82E are formed at the positions of drive electrodes 82B and 82C used to excite the flexural oscillation mode. A phase difference in the flexural oscillation mode opposite in sign relative to the longitudinal oscillation mode is created making it is easy to classify based on the phase difference between a frequency at which the longitudinal oscillation mode is dominant and a frequency at which the flexural oscillation mode is dominant. Thus, reliable control can be achieved based on the oscillation behaviors at each frequency ensuring a satisfactory drive force based on oscillation in the longitudinal oscillation mode.

Abstract: An adhesive layer is formed between a piezoelectric element and a baseboard by using an adhesive agent with a Shore D hardness of 80 HS or greater to couple the baseboard and the piezoelectric element. The adhesive layer is formed in a uniform thickness by placing two spacers on a transfer sheet and spreading the adhesive agent between these spacers. The baseboard and the piezoelectric element bonded together by the adhesive layer are heated in a pressed state to cause the adhesive layer to harden. The vibration loss in the adhesive layer can be reduced because the hardened adhesive layer has high hardness. In addition, variation in the vibration characteristics of a piezoelectric actuator can be reduced because the thickness of the adhesive layer is uniform.

Abstract: A diaphragm 10 is fixed to a base plate 102 by a screw 13. A lever 20 has a spring member 23, a rotor-fixing member 25, and an insertion hole 22 formed therein. By passing a shaft 21 through the insertion hole 22, the lever 20 is turnably supported so as to turn about its own axis. In a state in which the spring member 23 abuts against an eccentric pressure-adjusting cam 26, a pressing force for urging the diaphragm 10 via the rotor 100 is adjusted by turning the pressure-adjusting cam 26 so as to change an elastic force of the spring member 23.