A semi-resonant actuator assembly includes a resonating body comprising a piezoelectric plate having a first length, a first width, and a first thickness, and an inactive plate having a second length substantially equal the first length, a second width substantially equal to the first width, and second thickness. A thickness of the resonating body is provided by a sum of the first thickness of the active piezoelectric plate and the second thickness of the inactive plate.

A driving apparatus has a vibration plate, a vibrator having a piezoelectric element that excites vibration of the vibration plate, and first and second contact parts, and a friction member being in contact with the contact parts. The vibrator and the friction member relatively move with respect to each other, and the contact parts are provided at positions with and interpose an odd number of antinodal lines of vibration generated in a first direction of the vibrator along with excitation, and provided at positions with and interpose an odd number of nodal lines of vibration generated in a second direction of the vibrator along with excitation.

A driving apparatus which reduces power consumption as compared to conventional driving apparatuses. A voltage amplitude of first AC voltages is controlled based on a relative angle between a moving direction of a moving body, which is indicated by a driving command for moving the moving body, and a driving direction of a first vibrator, and a voltage amplitude of second AC voltages is controlled based on a relative angle between the moving direction and a driving direction of a second vibrator. Each of the first vibrator and the second vibrator is controlled based on a deviation between the driving command and a detected position of the moving body while the first AC voltages and the second AC voltages are being controlled. The driving direction of the first vibrator and the driving direction of the second vibrator cross each other.

A motor capable of holding a vibrator without increasing a dimension thereof in a traveling direction (driving direction) and without having looseness. The motor includes a vibrator and a holding unit that holds the vibrator, and moves the vibrator and a sliding member in frictional contact with the vibrator relative to each other by vibrating the vibrator. A pressurizing unit pressurizes the vibrator against the friction member, and holding springs generate a holding force for causing the holding unit to hold the vibrator. The holding unit is not disposed between the pressurizing unit and the vibrator. A holding direction of the holding force generated by the holding springs and a pressurizing direction of a pressurizing force generated by the pressurizing unit are substantially parallel to each other.

A vibration wave motor, includes a vibrator including an electro-mechanical energy conversion element and an elastic body, and a contact body, wherein the elastic body includes a flat plate portion on which the electro-mechanical energy conversion element is fixed, and a protruding portion, wherein the protruding portion includes a contact portion, a side wall portion, and a coupling portion that is configured to couple the contact portion and the side wall portion, and wherein a predetermined inequality is satisfied, where a thickness of the side wall portion in a direction orthogonal to the pressure direction is t1, and a distance in the pressure direction from a second surface of the flat plate portion to the coupling portion is h1, the second surface of the flat plate portion facing a first surface of the flat plate portion on which the electro-mechanical energy conversion element is fixed.

A vibration type actuator is provided that includes a first member that has a vibrator; a second member that extends in a predetermined direction and has a friction sliding surface where the vibrator is press-contacted; a third member that rotatably holds the second member with respect to an axis parallel to the predetermined direction; and a pressing unit that generates a first force for rotating the second member with respect to the axis relative to the third member. The first member is sandwiched between the second member and the third member by the first force. The first member is driven in a driving direction parallel to the predetermined direction relative to the second member by the vibration of the vibrator.

A vibrator of a vibration-type driving device according to an aspect of the present invention includes a first vibrating member that includes first protrusions protruding in a first direction, a second vibrating member that includes second protrusions protruding in a direction that is opposite to the first direction, and an electric-mechanical energy conversion element that is fixed to the first vibrating member. The first protrusions and the second protrusions each have a hollow structure, and the first vibrating member and the second vibrating member are disposed in such a manner that a surface of the first vibrating member on which the first protrusions are not formed and a surface of the second vibrating member on which the second protrusions are not formed face each other.

An ultrasonic motor includes a vibrator to which a piezoelectric element is fixed and a friction member having a frictional contact surface in contact with the vibrator. A pressurizing member pressurizes the vibrator toward the friction member using a resilient force of a coil spring. A pressurizing force setting unit transmits a driving force of a pressurizing force setting motor to a holding member and then sets the pressurizing force by altering an amount of deflection of the coil spring depending on the relative position of the holding member with respect to the pressurizing member. The friction member is driven relative to the vibrator by an elliptic vibration of the vibrator in a state where the projections provided on a vibration plate are brought into pressurized contact with the frictional contact surface of the friction member by the pressurizing force.

A driving circuit for a vibration type actuator includes an inductor and a capacitor which are connected in series to an electric-mechanical energy conversion element, in which, in a case where a series resonance frequency based on the inductor and the capacitor is set as fs, and a resonance frequency in a vibration mode other than vibration used for driving of the vibrator is set as fu, 0.73.Math.fu<fs<1.2.Math.fu is satisfied.

A vibration actuator that is capable of miniaturizing or obtaining stable drive performance. The vibration actuator moves a vibration body and a driven body relatively. The vibration actuator includes a support member that supports the vibration body. The support member includes a vibration section joined to the vibration body, a first fixing section and a second fixing section that are provided on both sides of the vibration body for fixing the support member at a predetermined position, a first support section that connects the vibration section with the first fixing section to support the vibration body, a second support section that connects the vibration section with the second fixing section to support the vibration body, and conduction members that extend from the vibration body to the first fixing section, extend from the vibration body to the second fixing section, and supply electric power to the vibration body.