JP4897016B2 - Piezoelectric motor - Google Patents

Description

  The present invention relates to a piezoelectric motor and a piezoelectric motor system that drive a driven body using a piezoelectric unit.

  Conventionally, in the field of multi-degree-of-freedom rotation drive control systems represented by pointing control of surveillance cameras and the like and robot joints, a drive mechanism or a motor system having a configuration in which single-axis drive motors are stacked in series in multiple stages is widely used. It has been. From the viewpoint of miniaturization and high accuracy, a multi-degree-of-freedom type drive mechanism or multi-degree-of-freedom type motor system composed of a support system using a gimbal mechanism or a joint mechanism and a drive system using a separately disposed electromagnetic motor or the like is adopted. May be. However, the conventional drive mechanism or motor system based on the gimbal mechanism or joint mechanism is not always satisfactory because the structure is complicated and the size is limited. In view of the situation, in recent years, research and development of spherical motors using piezoelectric elements have attracted attention. In particular, a piezoelectric motor that uses a piezoelectric unit to drive a sphere, which is a driven body, with frictional force is expected as a next-generation compact high-precision spherical motor.

  As a piezoelectric motor using a piezoelectric element, a “ball joint angle changing device” described in Patent Document 1 is known. In this ball joint angle changing device, the tip portions of three vibrators (piezoelectric units) arranged in a predetermined arrangement in a sphere housing member housing a ball joint sphere are brought into contact with the sphere. ing. Further, in order to maintain this contact state, the sphere is configured to be urged in the vibrator direction by a plurality of spring members arranged in a predetermined arrangement in the sphere housing member. In this state, the coupling portions of these vibrators are rotated in a desired predetermined direction, so that the ball joint sphere is rotated in a desired direction. Thereby, the angle of the ball joint is changed to a predetermined direction. This vibrator (piezoelectric unit) is composed of three vibrating elements (piezoelectric elements) that are integrated by joining the tip parts, and vibrates at the positions of three ridges centered on the apex of the regular triangular pyramid. An element (piezoelectric element) is arranged.

  As another conventional example of a piezoelectric motor using a piezoelectric unit, an “imaging device” described in Patent Document 2 is known. In this image pickup apparatus, the image pickup unit is a substantially spherical body, and its outer peripheral surface is formed of a convex spherical surface except for the portion of the image pickup optical system. An imaging optical system, an imaging element such as a CCD, etc. are provided inside the imaging unit. The housing (sphere) of the imaging unit is made of, for example, a magnetic material, and the convex spherical surface portion is adsorbed by a holding member made of an annular magnet. The holding member is fixed to the imaging apparatus main body. As a result, the imaging unit is pivotably held by the imaging apparatus main body by the magnetic force of the holding member. A drive mechanism is provided in the center of the central opening of the annular holding member. The drive mechanism is composed of a two-dimensional piezoelectric actuator and a friction member provided at substantially the center thereof. The friction member is configured to abut on the convex spherical surface of the imaging unit, move with the expansion and contraction of each arm of the two-dimensional piezoelectric actuator, and turn the imaging unit.

  According to the “ball joint angle changing device” described in Patent Document 1 and the “imaging device” described in Patent Document 2, the complexity of the gimbal mechanism and the joint mechanism is eliminated, and the drive is small and has a high degree of freedom. The mechanism can be realized.

  Since this type of piezoelectric motor is driven by friction, it is necessary to press the piezoelectric unit against the driven body. However, in Patent Document 1, a preload is applied using a plurality of spring members, and a preload portion made of a spring member and a guide portion for rotatably supporting a sphere on the periphery thereof. Is actually necessary. These preload portions and guide portions have caused an increase in the size of the motor, a reduction in the movable range, and an increase in driving load due to friction (increase in ineffective torque). Further, since the sphere, the vibrator, and the plurality of spring members are all disposed in the sphere housing member, there is a problem that the entire apparatus is further increased in size.

  Further, in Patent Document 2, a guide portion for rotatably supporting the imaging unit is configured by adsorbing the convex spherical surface portion of the imaging unit with a holding member made of an annular magnet. As the driving load due to the friction increases significantly (increase in reactive torque), the driving mechanism must generate enough driving force to overcome this frictional driving load. was there.

Japanese Patent No. 3065427 (FIG. 8) Japanese Unexamined Patent Publication No. 2000-165738 (FIG. 9)

  The present invention provides a piezoelectric motor and a piezoelectric motor system that can minimize the ineffective torque, improve the movable range, and reduce the size of the entire apparatus.

According to one aspect of the present invention, (a) the base and (b) the spherical driven body are in contact with each other and spaced apart from each other, and the driven body is stably held and driven in the direction of two degrees of freedom of rotation. And (c) a magnet that applies a preload to each of the plurality of piezoelectric units by magnetically attracting the driven body in a non-contact state, and each of the plurality of piezoelectric units vibrates. A first piezoelectric element installed so that the direction thereof is substantially horizontal with the base and obliquely intersects with the driving direction of the driven body, and the base so as to intersect the vibration direction of the first piezoelectric element at a substantially right angle The second piezoelectric element disposed substantially perpendicular to the electrode and the driven body are in contact with each other, the first and second piezoelectric elements are connected, and driven by the combined vibration of the first and second piezoelectric elements. Driving unit for driving a driven body using the driving plane of the body as an operation plane Comprises a piezoelectric motor preload force of the magnet is applied to the first and second piezoelectric elements are provided. According to another aspect of the present invention, (a) the base and (b) the spherical driven body are in contact with each other and are spaced apart from each other to hold the driven body stably and in the direction of three degrees of freedom of rotation. A plurality of piezoelectric units to be driven, and (c) a magnet that applies a preload to each of the plurality of piezoelectric units by magnetically attracting the driven body in a non-contact state, and each of the plurality of piezoelectric units includes: The first piezoelectric element installed so that the vibration direction is substantially horizontal with the base and obliquely intersects with the drive direction of the driven body, and the neutral axis and the neutral axis of the first piezoelectric element intersect at a substantially right angle. Each of the first and second piezoelectric elements, which has a crossing point, the vibration direction is substantially horizontal with the base, and is obliquely crossed with the driving direction of the driven body . neutral axis and the neutral axis intersect at a substantially right angle intersection, first及A third piezoelectric element disposed in a substantially perpendicular direction relative to the base so that the vibration direction and the vibration direction of the second piezoelectric element intersect substantially at right angles in contact with the driven member, the first to third And a driving unit that drives the driven body with the driving plane of the driven body as an operation plane by the combined vibration of the first to third piezoelectric elements, and the preload of the magnet is the first to first A piezoelectric motor applied to the three piezoelectric elements is provided.

  According to the present invention, it is possible to provide a piezoelectric motor and a piezoelectric motor system that can minimize the ineffective torque, improve the movable range, and reduce the size of the entire apparatus.

It is a block diagram which shows the structure of the piezoelectric motor system which concerns on embodiment of this invention. 1 is a top view of a piezoelectric motor according to an embodiment of the present invention. It is a figure which shows the structure of the gaze change camera module which concerns on embodiment of this invention. It is a figure for demonstrating the gaze change operation | movement of the gaze change camera module which concerns on embodiment of this invention. It is a figure which shows the structure of the gaze change camera module which concerns on embodiment of this invention. It is a figure for demonstrating the gaze change operation | movement of the gaze change camera module which concerns on embodiment of this invention. It is a top view which shows the structure of the piezoelectric motor which concerns on the modification of embodiment of this invention. It is a top view (BB sectional drawing of Drawing 7) showing composition of a piezoelectric motor concerning a modification of an embodiment of the invention. It is a top view which shows the structure of the piezoelectric motor which concerns on the modification of embodiment of this invention.

  Next, embodiments of the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. Further, the embodiments described below exemplify apparatuses and methods for embodying the technical idea of the present invention, and the technical idea of the present invention includes the material, shape, structure, The layout is not specified as follows. The technical idea of the present invention can be variously modified within the scope of the claims.

  As shown in FIG. 1, the piezoelectric motor system according to the embodiment of the present invention includes a piezoelectric motor 100 that drives a driven body 105 and a control unit 200 that controls the operation of the piezoelectric motor 100. As shown in FIGS. 1 and 2, the piezoelectric motor 100 is installed on the base 101 and a plurality of (first to third) supporting the driven body 105 so as to move or rotate freely. ) Piezoelectric units (two-degree-of-freedom piezoelectric units) 102, 103, 104 and the base 101, and the driven body 105 is magnetically attracted in a non-contact state to thereby provide first to third piezoelectric units 102, 103. , 104 are provided with magnets 109 for applying a preload.

  The magnet 109 has, for example, a ring shape, and is disposed on the Z axis with a predetermined gap w from the driven body 105. The magnet 109 magnetically attracts the driven body 105 in a non-contact state, and applies a preload to the first to third piezoelectric units 102, 103, and 104. As the magnet 109, a single electromagnet or a combination of a permanent magnet and an electromagnet can be used.

  The first to third piezoelectric units 102, 103, 104 are provided with a predetermined arrangement necessary for stably holding the driven body 105. In the example shown in FIG. It is equally distributed at 120 degrees in the direction.

  The first piezoelectric unit 102 includes a first piezoelectric element 102 a and a first piezoelectric element 102 a that are installed so that the vibration direction is substantially horizontal with the base 101 and is oblique to the driving direction of the driven body 105. The second piezoelectric element 102b disposed in a direction substantially perpendicular to the base 101 so as to intersect at right angles to the vibration direction of the first piezoelectric element 102a and the first and second piezoelectric elements 102a and 102b are connected to be driven. A drive unit 106 is provided for contacting the body 105 at the contact point P1 and for transmitting a driving force to the driven body 105 through friction between the combined vibrations.

  The second piezoelectric unit 103 includes a first piezoelectric element 103 a and a first piezoelectric element 103 a that are installed so that the vibration direction is substantially horizontal with the base 101 and is oblique to the driving direction of the driven body 105. A second piezoelectric element 103b disposed in a direction substantially perpendicular to the base 101 so as to intersect at right angles to the vibration direction of the first piezoelectric element 103a, and the first and second piezoelectric elements 103a and 103b. A drive unit 107 is provided for contacting the body 105 at a contact point P2 and for transmitting the driving force to the driven body 105 through friction between the combined vibrations.

  The third piezoelectric unit 104 includes a first piezoelectric element 104 a and a first piezoelectric element 104 a that are installed so that the vibration direction is substantially horizontal with the base 101 and is oblique to the driving direction of the driven body 105. The second piezoelectric element 104b disposed in a direction substantially perpendicular to the base 101 so as to intersect with the vibration direction of the first piezoelectric element 104b, and the first and second piezoelectric elements 104a and 104b are connected to be driven. A drive unit 108 for contacting the body 105 at a contact point P3 and transmitting the driving force to the driven body 105 through friction between the combined vibrations is provided.

  As each of the first and second piezoelectric elements 102a, 102b, 103a, 103b, 104a, and 104b, piezoelectric ceramics, electrostrictive ceramics, polymer piezoelectric bodies, a combination thereof, or a laminate thereof can be used.

  The driven body 105 is, for example, spherical, and is supported at contact points P1, P2, P3 with the first to third piezoelectric units 102, 103, 104, and the position is uniquely determined. On the other hand, the attitude of the driven body 105 is supported in a geometrically rotatable manner, but is a frictional force at the contact points P1, P2, P3 with the first to third piezoelectric units 102, 103, 104. The rotational motion is constrained, and the operations of the first to third piezoelectric units 102, 103, 104 are stopped. As long as a large external force exceeding the frictional force between the first to third piezoelectric units 102, 103, 104 and the driven body 105 does not work, the posture of the driven body 105 is maintained in that state.

  The control unit 200 is an electromagnet attractive force control system for adjusting the pre-pressure on the driven body 105 of the first to third piezoelectric units 102, 103, 104. The control unit 200 is connected to the attitude angle sensor 201 installed on the mounting surface 202 of the piezoelectric motor 100, the operation unit 203, the drive waveform generation unit 204 connected to the operation unit 203, and the drive waveform generation unit 204, respectively. A preload setting unit 208 connected to each of the attitude angle sensor 201 and the drive waveform generation unit 204, and an electromagnet amplifier 209 connected to the preload setting unit 208.

  The attitude angle sensor 201 measures the attitude of the piezoelectric motor 100 and transmits the attitude information S 1 to the preload setting unit 208. The operation unit 203 sets the drive conditions of the piezoelectric motor 100 and transmits the operation signal C1 to the drive waveform generation unit 204. The drive waveform generation unit 204 generates a voltage waveform (drive signal) to be applied to the first and second piezoelectric elements 102a, 102b, 103a, 103b, 104a, 104b based on the operation signal C1 from the operation unit 203. To do. The amplifiers 205, 206, and 207 are based on the drive signals E 1, E 2, E 3, E 4, E 5, E 6 from the drive waveform generator 204, and the first and second piezoelectric elements 102 a, 102 b, 103 a, 103 b, 104 a, 104 b. A predetermined drive voltage V1, V2, V3, V4, V5, and V6 is applied to.

  The preload setting unit 208 receives and applies the maximum value (drive signal) E0 of the applied voltages E1, E2, E3, E4, E5, and E6 from the drive waveform generation unit 204 and the posture information S1 from the posture angle sensor 201. Based on the maximum voltage value E0 and the information of the posture information S1, the preload value M1 is set by referring to a predetermined preload value or using a predetermined calculation formula. Here, the preload value M1 is set using both the maximum value E0 and the posture information S1 of the applied voltage. However, from the viewpoint of the use environment, the use situation, the required accuracy, etc., the applied voltage The preload value M1 may be set using only one of the maximum value E0 and the posture information S1. The electromagnet amplifier 209 receives the preload value M1 set by the preload setting unit 208 and generates a magnetic attraction force corresponding to the preload value M1, so that an electric current A1 to be applied to the coil 109a of the annular magnet 109 is excited. To do.

  When operating the piezoelectric motor 100 and changing the attitude of the driven body 105, the first and second piezoelectric elements 102a, 102b, 103a, 103b of the first to third piezoelectric units 102, 103, 104, respectively. , 104a, 104b are applied with predetermined drive voltages V1, V2, V3, V4, V5, V6 using amplifiers 205, 206, 207, and the drive units 106 of the first to third piezoelectric units 102, 103, 104 are applied. , 107, and 108 apply a motion in accordance with a known driving method, for example, an elliptical motion or a rapid deformation motion, to rotationally drive the posture of the driven body 105 in an arbitrary two-degree-of-freedom direction.

  As described above, according to the piezoelectric motor system including the piezoelectric motor 100 according to the embodiment of the present invention, the driven body 105 is rotatably supported by the first to third piezoelectric units 102, 103, and 104. The driven body 105 is rotationally driven in any two degrees of freedom by a combination of the combined vibrations of the first to third piezoelectric units 102, 103, and 104, and the annular magnet 109 magnetizes the driven body 105 in a non-contact state. Since it is configured to suck and apply pre-pressure to the first to third piezoelectric units 102, 103, 104, other than the contact points P1, P2, P3 with the first to third piezoelectric units 102, 103, 104 The frictional contact portion can be eliminated, and a driving load due to friction at other components does not occur in principle. As a result, since the ineffective torque can be minimized, the first to third piezoelectric units 102, 103, and 104 can be expected to be greatly reduced in size.

  In addition, the first to third piezoelectric units 102, 103, 104 and the magnet 109 are concentratedly arranged below the driven body 105 (in the vicinity of one hemisphere), and the magnet 109 is arranged in the first to third piezoelectric units 102, Since it is arranged in a polygonal (triangular) area formed by connecting the positions of 103 and 104 with straight lines, the entire device can be downsized and the movable range can be greatly improved. It becomes. Taking advantage of such downsizing and multi-degree-of-freedom driving, it can be expected to be used as a direction control for a surveillance camera or the like, or as a robot joint.

  In addition, the first to third piezoelectric units 102, 103, and 104 have a large vibration displacement (thickness) but a generated force (area) compared to a ring-type vibrator in which a piezoelectric element is attached in a ring shape. ) Is small. If the generated force is small, the preload cannot be increased, and the rate of fluctuation caused by the change in the attitude of the piezoelectric motor 100 with respect to the initial preload increases. Since the piezoelectric motor 100 is driven by friction, the stability of the drive characteristics may be impaired if the ratio of the pre-pressure fluctuation is large. In the embodiment of the present invention, the attractive force of the electromagnet 109 is controlled according to the posture of the piezoelectric motor 100 and the maximum value of the applied voltage of the piezoelectric unit, and the posture of the piezoelectric motor 100 and the first to third piezoelectric units 102, Since the preload (the magnetic attractive force of the electromagnet 109) is actively adjusted according to the change in the driving state of 103, 104, the attitude of the piezoelectric motor 100 and the first to third piezoelectric units 102 are configured. , 103, 104, even when the driving state fluctuates, it is possible to improve the stability of the driving characteristics.

(First modification)
As a first modification of the embodiment of the present invention, a configuration of a line-of-sight changing camera module in which a camera module is mounted on the piezoelectric motor 100 will be described. As shown in FIGS. 3 and 4, the line-of-sight changing camera module 150 includes a piezoelectric motor 100, a driven body 151, and a camera module 120 embedded in the vicinity of the inner central portion of the driven body 151.

  The camera module 120 is fixedly arranged inside the driven body 151. The driven body 151 has an outer peripheral surface to which a driving force is transmitted from the first to third piezoelectric units 102, 103, and 104 processed into a spherical shape. The line-of-sight change camera module 150 includes image processing means for rotating the captured image as necessary.

  When the piezoelectric motor 100 is operated and the driven body 151 is rotationally driven, the line-of-sight direction of the camera module 120 can be changed to an arbitrary two-degree-of-freedom direction. For example, the line-of-sight direction D1 of the camera module 120 that is oriented in the vertical direction (upward) in FIG. 4 can be changed to the line-of-sight direction D2 in the horizontal direction (lateral direction) as shown in FIGS.

  Further, only the parts different from the piezoelectric motor 100 shown in FIGS. 1 and 2 will be described, and overlapping description of common parts will be omitted.

  According to the line-of-sight changing camera module 150 according to the first modification of the embodiment of the present invention, the first to third piezoelectric units 102, 103, 104 and the annular magnet 109 are driven by mounting the camera module 120. Since it is configured to be concentrated below the body 151 (near one hemisphere), an image of 360 degrees around (referred to as “omnidirectional”) can be taken while realizing downsizing of the entire apparatus.

(Second modification)
As shown in FIGS. 7 and 8, a piezoelectric motor 300 according to a second modification of the embodiment of the present invention is installed on a driven body 105, a substantially annular base 301, and the base 301. , First to third piezoelectric units (three-degree-of-freedom piezoelectric units) 302, 303, and 304 equally arranged at 120 degrees in the circumferential direction around the Z ′ axis, and the driven body 105 and a predetermined number on the Z ′ axis The annular magnet 109 is provided with a gap w.

  The annular magnet 109 applies pre-pressure to the first to third piezoelectric units 302, 303, and 304 by magnetically attracting the driven body 105 in a non-contact state.

  In the first piezoelectric unit 302, the neutral axes of the first to third piezoelectric elements 302a, 302b, and 302c are arranged so as to intersect each other substantially at right angles and have intersections. The first and second piezoelectric elements 302 a and 302 b are provided such that their vibration directions are substantially horizontal to the base 301. The third piezoelectric element 302 c is provided so that the vibration direction thereof is substantially perpendicular to the base 301. The drive unit 306 couples the first to third piezoelectric elements 302a, 302b, and 302c, and their combined vibration transmits a driving force to the driven body 105 through friction at the contact point P4.

  In the second piezoelectric unit 303, the neutral axes of the first piezoelectric element 303a, the second piezoelectric element 303b, and the third piezoelectric element (not shown) are arranged so as to intersect each other at a substantially right angle. The first and second piezoelectric elements 303 a and 303 b are provided so that their vibration directions are substantially horizontal to the base 301. The third piezoelectric element (not shown) is provided such that its vibration direction is substantially perpendicular to the base 301. The drive unit 307 connects the first piezoelectric element 303a, the second piezoelectric element 303b, and the third piezoelectric element (not shown), and their combined vibration causes friction to be driven via the contact point P5. The driving force is transmitted to 105.

  In the third piezoelectric unit 304, the neutral axes of the first to third piezoelectric elements 304a, 304b, and 304c are arranged so as to intersect at a substantially right angle. The first and second piezoelectric elements 304 a and 304 b are provided such that their vibration directions are substantially horizontal to the base 301. The third piezoelectric element 304 c is provided so that the vibration direction thereof is substantially perpendicular to the base 301. The driving unit 308 connects the first to third piezoelectric elements 304a, 304b, and 304c, and their combined vibration transmits driving force to the driven body 105 through friction at the contact point P6.

  The driven body 105 is supported at contact points P4, P5, and P6 with the first to third piezoelectric units 302, 303, and 304, and its position is uniquely determined. On the other hand, the posture of the driven body 105 is supported in a geometrical manner so as to be freely rotatable, but is a frictional force at contact points P4, P5, P6 with the first to third piezoelectric units 302, 303, 304. As long as the rotational motion is constrained and the operation of the first to third piezoelectric units 302, 303, and 304 is stopped and a large external force exceeding the frictional force with the driven body 105 does not work, The posture of the driven body 105 is maintained in that state.

  When the piezoelectric motor 300 is operated to change the posture of the driven body 105, the first to third piezoelectric elements 302a, 302b, 302c, 303a, and 303b of the first to third piezoelectric units 302, 303, and 304 are used. , 303c, 304a, 304b, 304c, a predetermined voltage is applied using an amplifier (not shown), and a known driving method is applied to the driving units 306, 307, 308 of the first to third piezoelectric units 302, 303, 304. The posture of the driven body 105 is rotationally driven in an arbitrary three-degree-of-freedom direction by applying a motion according to the above, for example, an elliptical motion or a rapid deformation motion.

  Only parts different from the piezoelectric motor 100 shown in FIG. 1 and FIG.

  As described above, according to the piezoelectric motor 300 according to the second modification of the embodiment of the present invention, the driven body 105 can be freely rotated by the three sets (first to third) of the piezoelectric units 302, 303, and 304. And the driven body 105 is rotationally driven in an arbitrary three degrees of freedom direction by a combination of combined vibrations of the first to third piezoelectric units 302, 303, and 304, and the annular magnet 109 causes the driven body 105 to be driven. Since the pre-pressure is applied to the first to third piezoelectric units 302, 303, and 304 by magnetic attraction in a non-contact state, the contact point P4 with the first to third piezoelectric units 302, 303, and 304 is obtained. , P5, and P6 other than the friction contact portions can be eliminated, and a driving load due to friction at other constituent portions does not occur in principle. As a result, since the ineffective torque can be minimized, the first to third piezoelectric units 302, 303, and 304 can be expected to be significantly downsized.

  The line-of-sight changing camera module 150 according to the first modification is configured using the piezoelectric motor 100 of the two-degree-of-freedom piezoelectric unit, but using the piezoelectric motor 300 of the three-degree-of-freedom piezoelectric unit according to the second modification. It may be configured. In the line-of-sight changing camera module 150, image processing means for performing image rotation processing is used as necessary. However, by configuring the line-of-sight changing camera module using the piezoelectric motor 300, rotation driving with three degrees of freedom is performed. By taking advantage of this feature, it is possible to realize image inclination correction that could not be realized by the piezoelectric motor 100, so that no image processing means is required. Furthermore, since no image processing is required, the image captured by the mounted camera module 120 can capture a stable image with high real-time characteristics around 360 degrees (referred to as omnidirectional).

(Other embodiments)
Although the present invention has been described according to the embodiment, it should not be understood that the description and drawings constituting a part of this disclosure limit the present invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art.

  For example, although the case where three sets of two-degree-of-freedom (cross type) piezoelectric units or three-degree-of-freedom (truss type) piezoelectric units are combined has been described, the number of piezoelectric units to be combined is not particularly limited. For example, as shown in FIG. 9, four or more sets of piezoelectric elements may be combined such that four sets of two-degree-of-freedom piezoelectric units 402, 403, 404, and 405 are combined.

  Moreover, although the example which rotates a spherical body as shown in FIG. 1 was demonstrated as the to-be-driven body 105, it is not specifically limited. For example, a flat plate may be used as the driven body 105 and the driven body 105 may be moved linearly.

  Further, instead of the magnet 109 shown in FIG. 1, a plurality of magnets may be disposed in the vicinity of the respective installation positions of the piezoelectric units 102, 103, and 104.

  Further, although the magnet 109 and the piezoelectric units 102, 103, and 104 shown in FIG. 1 are arranged below the driven body 105, they may be arranged above the driven body according to the installation environment.

  As described above, the present invention naturally includes various embodiments not described herein. Therefore, the technical scope of the present invention is defined only by the invention specific matters according to the scope of claims reasonable from the description.

DESCRIPTION OF SYMBOLS 100,300 ... Piezoelectric motor 101,301 ... Base 102,103,104,302,303,304 ... Piezoelectric unit 102a, 102b, 103a, 103b, 104a, 104b, 302a, 302b, 302c, 303a, 303b, 303c, 304a, 304b ... Piezoelectric elements 105, 151 ... Driven bodies (spheres)
106, 107, 108, 306, 307, 308... Driving unit 109... Annular electromagnet 109 a .. coil 120 .. camera module 150. ... Drive waveform generation unit 205, 206, 207 ... Amplifier 208 ... Preload setting unit 209 ... Electromagnetic amplifier

Claims (4)

The base,
A plurality of piezoelectric units that are respectively in contact with and separated from the spherical driven body, hold the driven body stably, and drive in the direction of two degrees of freedom of rotation;
A magnet that applies a preload to each of the plurality of piezoelectric units by magnetically attracting the driven body in a non-contact state;
Each of the plurality of piezoelectric units is
A first piezoelectric element installed such that a vibration direction is substantially horizontal with the base and obliquely intersects with a drive direction of the driven body;
A second piezoelectric element disposed in a substantially vertical direction with respect to the base so as to intersect the vibration direction of the first piezoelectric element at a substantially right angle;
The first and second piezoelectric elements are connected in contact with the driven body, and the driven body is driven with the driving plane of the driven body as an operation plane by the combined vibration of the first and second piezoelectric elements. A drive unit
A piezoelectric motor, wherein a pre-pressure of the magnet is applied to the first and second piezoelectric elements. The base,
A plurality of piezoelectric units that are respectively in contact with and separated from the spherical driven body, hold the driven body stably, and drive in the direction of three degrees of freedom;
A magnet that applies a preload to each of the plurality of piezoelectric units by magnetically attracting the driven body in a non-contact state;
Each of the plurality of piezoelectric units is
A first piezoelectric element installed such that a vibration direction is substantially horizontal with the base and obliquely intersects with a drive direction of the driven body;
The neutral axis of the first piezoelectric element and the neutral axis intersect with each other at a substantially right angle and have an intersection, and the vibration direction is substantially horizontal with the base and is oblique to the drive direction of the driven body. A second piezoelectric element ,
The neutral axis and the neutral axis of each of the first and second piezoelectric elements intersect at a substantially right angle at the intersection, and the vibration direction and the vibration direction of the first and second piezoelectric elements intersect at a substantially right angle. A third piezoelectric element disposed substantially perpendicular to the base;
The first to third piezoelectric elements are connected in contact with the driven body, and the driven body is driven with the driving plane of the driven body as an operation plane by the combined vibration of the first to third piezoelectric elements. A drive unit
A piezoelectric motor, wherein a pre-pressure of the magnet is applied to the first to third piezoelectric elements.   3. The piezoelectric motor according to claim 1, wherein the magnet is disposed in a polygonal region formed by connecting the positions of the plurality of piezoelectric units with straight lines. 4.   4. The piezoelectric motor according to claim 1, wherein the piezoelectric motor includes a plurality of the magnets, and the plurality of magnets are disposed in the vicinity of the respective installation positions of the piezoelectric units.