A vibration type motor includes a limiter configured to limit a distance between a movable guide member and a fixed guide member. The limiter has first, second, and third limiting areas. The first limiting area is disposed between a first roll member and a second roll member in one direction. The second limiting area is disposed on the same side as the second roll member with respect to the first roll member and distant from the second roll member in the one direction. The third limiting area is disposed on an opposite side of the second roll member with respect to the first roll member in the one direction. A length of the first limiting area in another direction orthogonal to the one direction is equal to or longer than that of each of the second limiting area and the third limiting area in the one direction.

A lens barrel includes: an electromechanical conversion element; an elastic body having a joining surface, a drive surface, and grooves; a motion member rotating by vibration wave of the drive surface; a rotating ring having a recess part and rotating by rotation of the motion member; a moving ring engaged to the recess part and moving to an optical axis direction by rotation of the rotating ring; and a lens held in the moving ring; wherein the element is made of a material having sodium potassium niobate, potassium niobate, sodium niobate or barium titanate, wherein a value of T/(B+C) is within a range of from 1.3 to 2.8 when: length from the drive surface to a base unit of the groove is defined as T; length from the base unit of the groove to the joining surface is defined as B; and thickness of the element is defined as C.

A vibration wave motor includes an element configured to be displaced by application of voltage, and an annular elastic body having a bottom surface coming into contact with the element and a drive surface having a groove, configured to drive a moving element by a vibration wave produced on the drive surface by displacement of the element. The element has a density of 4.2 to 6.0×10.sup.3 kg/m.sup.3. A value of [(T/B)÷W] is in a range of 0.84 to 1.94, where T represents a depth of the groove, B represents a distance from a bottom part of the groove to the bottom surface, and W represents a radial width of the elastic body.

A vibration-type actuator includes a vibrating body including an annular elastic member and an electric-mechanical energy conversion element, and an annular contact body configured to move relative to the vibrating body. The contact body includes a base portion, a support portion annularly extending from the base portion in a radial direction of the contact body, and a friction member provided at the support portion, formed separately from the support portion, and being in contact with the vibrating body. The friction member includes a first part extending in a direction along a central axis of the annular contact body, and a second part extending in the radial direction, the first part and the second part being connected to the support portion. The first part includes a portion that is connected by being either internally or externally fitted to the support portion in the radial direction.

A vibration motor includes a first vibrating body including a first projection and a second vibrating body including a second projection, the first vibrating body and the second vibrating body receiving electric power and vibrating to generate a driving force and transmitting the driving force to a driven section, a first coil spring configured to urge the first vibrating body and the second vibrating body in a driving direction and restrict positions of the first vibrating body and the second vibrating body in the driving direction, and a case housing the first vibrating body, the second vibrating body, and the first coil spring. The first vibrating body, the second vibrating body, and the first coil spring are arranged in the driving direction. The number of first coil springs is smaller than the number of first and second vibrating bodies in the urging direction.

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 vibratory actuator includes a vibration member, a contact member, and a pressure member. The vibration member includes an elastic member, having protrusions. The contact member is in contact with the elastic member and moves in a direction relative to the vibration member. The pressure member pressurizes the vibration member and the contact member. Each of the protrusions includes a first contact surface in contact with the contact member. The contact member has a second contact surface made of metal sintered material and in contact with the vibration member. A ratio of a maximum amount of depression on the second contact surface in the direction of pressurization by the pressure member to a width of the first contact surface in a direction perpendicular to the direction of movement of the contact member relative to the vibration member and the direction of pressurization by the pressure member is 0.05% or less.

A lens barrel includes an element displaced by application of voltage; an elastic body having a contact surface coming into contact with the element, a drive surface to produce a vibration wave by displacement of the element, and a plurality of grooves; a moving element come into contact with the drive surface and rotated by the vibration wave; an annular ring rotated by rotating of the moving element; and a lens moved in an optical axis direction by rotating of the annular ring; wherein the element mainly contains a material having potassium sodium niobate, potassium niobate, sodium niobate, or barium titanate, wherein a value of [(T/B)÷W] is in a range of 0.84 to 1.94, where T represents a depth of the groove, B represents a distance from a bottom part of the groove to the contact surface, and W represents a radial width of the elastic body.

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.

The invention relates to an annular or hollow cylindrical ultrasonic actuator, on the end faces of which are arranged n≥2 friction elements, and on the outer peripheral surface of which are arranged 2n excitation electrodes, spaced apart from one another in each case by a separating gap, each of the friction elements being arranged in the region of a separating gap, wherein, between friction elements that are adjacent with respect to the periphery of the ultrasonic actuator and are located on different end faces, two excitation electrodes are arranged such that, when the ultrasonic actuator is electrically excited, the friction elements of both end faces simultaneously perform a movement which is suitable for driving an element to be driven to rotate in the same direction. The invention further relates to an ultrasonic motor having an ultrasonic actuator of this kind and having a holding device in which the ultrasonic actuator is inserted.