An acoustic device includes a piezoelectric element, an attachment member to which the piezoelectric element is attached, and a spacer. The piezoelectric element includes first and second principal surfaces opposing each other. The attachment opposes the first principal surface. The spacer is disposed between the piezoelectric element and the attachment member in such a manner as to form an acoustic space between the piezoelectric element and the attachment member. The spacer includes an adhesive layer including a principal surface in contact with the first principal surface and a principal surface in contact with the attachment member.

Method for operating an ultrasonic motor with an ultrasonic actuator formed as a plate and an electrical excitation device. The ultrasonic actuator has at least four identical volume regions arranged symmetrically in relation to a transverse plane and in relation to a longitudinal plane, each volume region forming acoustic standing waves and static bending deformations. The electrical excitation device provides at least one electric alternating voltage and two static electric voltages the at least one alternating voltage U1 being applied in a dynamic operating mode simultaneously to two of the generators for forming an acoustic standing wave in the ultrasonic actuator, and the two static electric voltages being applied in a static operating mode simultaneously to all generators for forming a static bending deformation of the ultrasonic actuator.

A vibration type motor relatively moves, in a first direction, a vibrator whose vibration is excited by an electromechanical energy conversion element and a contact member configured to contact the vibrator, and includes a vibrator holder configured to hold the vibrator, a holding mechanism configured to hold the vibrator holder so as to restrict a displacement of the vibrator holder in the first direction and to enable the vibrator holder to be displaced in a direction orthogonal to the first direction, a press mechanism configured to press the vibrator against the contact member in a second direction, and a damper configured to contact a plurality of components among the vibrator holder, components of the holding mechanism, and components of the press mechanism.

A control method of a piezoelectric driving device which includes a vibrator including a piezoelectric element and vibrating by application of a drive signal to the piezoelectric element, a driven unit moving by the vibration of the vibrator, a drive signal generation unit generating the drive signal based on a pulse signal, the control method including: stopping the application of the drive signal to the piezoelectric element at the time when a driving speed of the driven unit is a reference speed, in a case of stopping driving of the driven unit.

A piezoelectric actuator includes a vibrating section including a piezoelectric element, a distal end face, and a recess opened on the distal end face and a protrusion section including a base that overlaps the recess in plan view of the distal end face and is fixed to the distal end face and a projection that is provided in the base and projects in an opposite direction of the distal end face, the protrusion section transmitting a driving force of the vibrating section to a driven section. In plan view of the distal end face, the projection is disposed within a range of the recess.

A piezoelectric motor includes a piezoelectric actuator, a holding member that holds the piezoelectric actuator, a housing in which the piezoelectric actuator and the holding member are placed, a first positioning pin that positions the holding member and the housing, and a first fixing part that fixes the first positioning pin. In the piezoelectric motor, the first positioning pin is fixed to one of the holding member and the housing, and a first hole portion in which the first positioning pin is placed is provided in the other of the holding member and the housing. The first fixing part fixes relative positions of the first hole portion and the first positioning pin.

A piezoelectric drive device includes a vibrator having a vibrating portion including a piezoelectric element, and a convex portion placed in the vibrating portion, an urging member including a base, a holding portion holding the vibrator, and a spring portion coupled to the base at one end and coupled to the holding portion at another end and urging the convex portion toward a driven unit, wherein d1>d2 in a natural state in which the vibrator is not urged by the urging member, where a separation distance between the one end and the convex portion along directions of the longitudinal direction is d1 and a separation distance between the other end and the convex portion is d2, and |d1−d2| in an urging state in which the vibrator is urged toward the driven unit by the urging member is smaller than |d1−d2| in the natural state.

A piezoelectric driving device includes a piezoelectric vibrating body and a driving circuit. The piezoelectric vibrating body includes a contact which extends in a first direction and comes into contact with a driven member, a first piezoelectric element which generates bending vibration in a direction intersecting with the first direction in accordance with a first driving voltage, and a second piezoelectric element which generates longitudinal vibration in the first direction in accordance with a second driving voltage. The piezoelectric vibrating body is configured such that a resonance frequency of the longitudinal vibration is higher than a resonance frequency of the bending vibration. The driving circuit sets a driving frequency of each of the first driving voltage and the second driving voltage to be equal to or higher than the resonance frequency of the longitudinal vibration.

A piezoelectric drive device includes two vibrators having vibrating portions with piezoelectric elements and transmitting portions placed in the vibrating portions and transmitting drive forces to a driven member (e.g. a slider), and a fixing portion having through holes (first through hole, second through hole)into which pins or screws are inserted. The two vibrators are placed adjoiningly along a drive direction of the slider, and the fixing portion is placed between the two vibrators and fixing the two vibrators.

There is provided a control method for a piezoelectric driving device including a vibrating body including a piezoelectric element for driving and configured to vibrate when a driving signal is applied to the piezoelectric element for driving, a section to be driven that is driven by the vibration of the vibrating body, and a driving-signal generating section configured to generate the driving signal using a pulse signal generated based on a target pulse duty ratio. When the target pulse duty ratio is smaller than a predetermined value, the driving signal generated by the driving-signal generating section is an intermittently generated periodic signal.