A vibration actuator is capable of reducing differences in vibration phase and vibration amplitude without raising a voltage of a drive circuit when driving a contact member using a plurality of vibrators connected in series. The vibration actuator includes a vibrator device and a contact member that moves relative to the vibrator device. The vibrator device includes transformers of which primary coils are connected in series, and vibrators that are respectively connected in parallel to secondary coils of the transformers.

The driving apparatus comprises a vibrating body which includes an electro-mechanical energy conversion device, and drives a vibration-wave motor which moves the vibrating body and a driven body relatively to each other. The electro-mechanical energy conversion device has sensor electrodes that output detecting signals corresponding to vibrations of the vibrating body. Based on the detecting signals, the driving apparatus determines a direction in which the vibrating body and the driven body are to be moved relatively to each other.

A vibrating actuator includes a contact body and a vibrating body that vibrates, has an energy conversion element, and has an elastic body in contact with the contact body to move relative to each other from the vibration. The contact body has a base part, a thin plate part, a support part, and a friction member. The thin plate part extends from the base part toward an annular center axis of the base part and the support part is disposed at an end of the thin plate part. The friction member is disposed to the support part as a member separate from the support part and in contact with the elastic body. Density of the friction member is higher than density of the thin plate part. A weight ratio of the thin plate part to a total weight of the friction member and the support part is 0.5 to 1.5.

Provided is a lead-free piezoelectric material reduced in dielectric loss tangent, and achieving both a large piezoelectric constant and a large mechanical quality factor. A piezoelectric material according to at least one embodiment of the present disclosure is a piezoelectric material including a main component formed of a perovskite-type metal oxide represented by the general formula (1): Na.sub.x+s(1−y)(Bi.sub.wBa.sub.1−s−w).sub.1−yNb.sub.yTi.sub.1−yO.sub.3 (where 0.84≤x≤0.92, 0.84≤y≤0.92, 0.002≤(w+s)(1−y)≤0.035, and 0.9≤w/s≤1.1), and a Mn component, wherein the content of the Mn is 0.01 mol % or more and 1.00 mol % or less with respect to the perovskite-type metal oxide.

A lens apparatus includes a base barrel, a lens movable to an object side and an image side relative to the base barrel, an actuator configured to move the lens, a drive board that includes an electric element configured to drive the actuator, and a board holding member configured to hold the drive board and attached to the base barrel from the object side.

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.

A vibration-type actuator capable of suppressing reduction in holding torque or holding force under influence of humidity. A vibration-type actuator 10 includes a vibrating body 2 and a driven body 1. The vibrating body 2 has a piezoelectric element 2c and an elastic body 2b. The driven body 1 is in contact with the vibrating body 2. The vibration-type actuator 10 moves the vibrating body 2 and the driven body 1 relatively to each other by vibration excited to the vibrating body 2. At least one of a first contact portion of the vibrating body 2 and a second contact portion of the driven body 1 includes a stainless-steel sintered body with pores and at least some of the pores are impregnated with a resin.

A high-torque and high-precision ultrasonic motor with a self-protection function and an implementation mode of the high-torque and high-precision ultrasonic motor are provided. In the device, a gasket encloses an output shaft of an ultrasonic motor body. A harmonic reducer encloses a shell of the ultrasonic motor body. A motor shaft penetrates through the ultrasonic motor body. The end, close to the motor shaft, of the ultrasonic motor body is defined as a top end, and the bottom end of the motor shaft is sequentially enclosed with an encoder support and a high-precision encoder assembly. The gasket, the harmonic reducer, the encoder support and the high-precision encoder assembly are sequentially arranged from the ultrasonic motor body to the bottom end of the motor shaft. After the ultrasonic motor body decelerates and increases torque, the motor shaft outputs rotating speed and torque.

A vibration wave motor includes an annular oscillator, and an annular moving member provided so as to be in press contact with the oscillator. The oscillator includes an annular vibrating plate, and an annular piezoelectric element provided on a first surface of the vibrating plate. The vibrating plate is in contact with the moving member via a second surface of the vibrating plate, which is opposite the first surface. The piezoelectric element has a plurality of drive phase electrodes. When a driving region represents a region of the oscillator in which the drive phase electrodes are provided, and a non-driving region represents a remaining region of the oscillator, a contact area ratio S1 between the vibrating plate and the moving member in the non-driving region is less than a contact area ratio S2 between the vibrating plate and the moving member in the driving region.