An aspect of the present invention relates to a vibration element comprising: a substrate; a ceramic layer containing glass and provided on the substrate; and a piezoelectric element comprising an electrode layer fixed to the substrate with the ceramic layer therebetween and a piezoelectric layer, wherein the piezoelectric layer, the electrode layer, the substrate, and the ceramic layer are integrated by the piezoelectric layer, the electrode layer, the substrate, and the ceramic layer being sintered together at a sintering temperature of from 800° C. or higher to 940° C. or lower.

A piezoelectric drive device driving a driven member by a projecting portion provided on one end of a vibrator including a piezoelectric element, includes a fixing portion fixing the piezoelectric drive device, a holding portion holding the vibrator, an urging portion coupled to the fixing portion and urging the holding portion including the vibrator in a direction toward the projecting portion, a weight portion provided at an opposite side to the projecting portion in the holding portion, and an elastic portion placed between the holding portion and the weight portion.

A driving unit includes a rotor, a plurality of vibratory members, and a driving circuit. The vibratory members each include an action part in contact with the outer periphery of the rotor and a motional part including an expansion-and-contraction driver to expand and contract in response to an applied voltage. The motional part allows the action part to slide along the rotational direction of the rotor. The driving circuit applies voltages to the expansion-and-contraction drivers. The vibratory members are disposed in such a way that the action parts of the vibratory members hold the rotor between the action parts.

A piezoelectric drive device includes a piezoelectric drive portion which includes a contact portion capable of coming into contact with a driven body and a piezoelectric material, and a drive circuit which drives the piezoelectric drive portion. The drive circuit sets an allowable maximum output torque Tlim or less to an allowable output torque range, sets output torque Td of the piezoelectric drive portion so as to be within the allowable output torque range, and operates the piezoelectric drive portion. The allowable maximum output torque Tlim is expressed by the following Expression (1).
Tlim=r1×μk×Ns×fs  (1)
In the expression, r1 is a distance between a rotation center of the driven body and a contact position of the contact portion, μk is a dynamic friction coefficient between the driven body and the contact portion, Ns is a pressing force by which the contact portion presses the driven body when an operation of the piezoelectric drive portion stops, and fs is a coefficient of 1 or less.

A vibration type actuator includes a vibrator, including a protrusion and a piezoelectric element, that is arranged to vibrate in response to a voltage, and a contact member having a contact surface which the protrusion contacts. The vibrator and the contact member rotate relative to each other around a first axis. The vibrator is tilted to the contact surface by a predetermined angle.

A piezoelectric drive device includes a rotor which has an output section for outputting a rotational force and a transmission section disposed on an outer periphery of the output section, and rotates around a rotational axis, and a vibrating part which has a piezoelectric element, and rotates the rotor due to a deformation of the piezoelectric element. The transmission section has a first portion and a second portion different from each other in position in a radial direction from the output section toward the transmission section, the first portion is coupled to the output section, the second portion is higher in Young's modulus than the first portion, the second portion is higher in mass per unit volume than the first portion, and the vibrating part makes contact with the transmission section at a position overlapping the second portion in a plan view from an axial direction of the rotational axis.

A motor includes a first vibrator, a plurality of biasing parts that are disposed around the first vibrator and that presses the first vibrator onto a contacting member in contact with the first vibrator, a first pressing member that is biased by the plurality of biasing parts and that includes a pressing part pressing the first vibrator by biasing force of the plurality of biasing parts, and a second pressing member that is biased by the plurality of biasing parts. The first vibrator and the contacting member move relatively by vibrations that occur in the first vibrator. The first and second pressing members integrally moves while the first vibrator moves. The first pressing member and the first vibrator are tiltable around a first direction orthogonal to both of a moving direction of the first vibrator and a biasing direction of the plurality of biasing parts.

A vibration actuator capable of determining positional relationship between a vibration body and driven body with high accuracy while keeping a pressurized contact state therebetween. The driven body contacts with the vibration body in a first direction and moves in a second direction perpendicular to the first direction. A holding member that holds the vibration body has two holes. A support member that supports the holding member has two projections that fit in the holes to form first and second fitting parts. The projection contacts with the hole in the second direction and in a third direction perpendicular to both the first and second directions in the first fitting part. The projection contacts with the hole in the third direction in the second fitting part. A contact range of the projection and hole in the third direction in the first fitting part differs from that in the second fitting part.

Information regarding a rotational speed is detected by utilizing a variation in the amplitude at a frequency corresponding to the number of a plurality of protrusions of a vibrating member generated in an S-phase signal detected from a vibration detection electrode of a vibration-type actuator.

A piezoelectric actuator includes a first piezoelectric element that outputs a first signal when being driven, a second piezoelectric element that outputs a second signal when being driven, a signal combining part that delays phase of the second signal and outputs a composite signal by combination of the second signal and the first signal, and a drive state determination part that determines respective drive states of the first piezoelectric element and the second piezoelectric element based on the composite signal.