JP2007306799A - Ultrasonic actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ultrasonic actuator enhanced in efficiency by suppressing a driving element from inhibiting the vibration of a piezoelectric element. <P>SOLUTION: The ultrasonic actuator includes the piezoelectric element 1 which performs bending vibration and stretching vibration, and the driving element 2 which is attached by point contact on a plane facing the vibrating direction of the bending vibration in the piezoelectric element 1 and outputs driving force by operating in accordance with the vibration of the piezoelectric element 1. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a vibration actuator used in various electronic devices, and more particularly to an ultrasonic actuator using an electromechanical transducer.

A conventional ultrasonic actuator is shown in FIGS. FIG. 13 is a perspective view of a piezoelectric element portion of a conventional ultrasonic actuator, and FIG. 14 is a sectional view thereof.

  The piezoelectric element 100 is supported by five support portions 101A, 101B, 101C, 101D, and 101E. This piezoelectric element 100 is formed with four-divided electrodes 102a, 102b, 102c, and 102d, and the piezoelectric element on the opposite side. A full-surface electrode (not shown) is formed on the entire surface of the element.

  The wire 104a is connected to the electrode 102a by the solder 105a and the electrode 102d by the solder 105d. The wire 104b is connected to the electrode 102b by the solder 105b and to the electrode 102c by the solder 105c. Furthermore, the wire 104g is connected to the entire surface electrode. A voltage is applied to the piezoelectric element 100 through these wires 104a, 104b, and 104g.

  A driver element 102 is provided on the upper surface of the piezoelectric element 100, and a tip portion thereof is in contact with the movable body 103. The distal end portion of the driver element 102 is pressed against the movable body 103 by the support portion 101C, whereby the frictional force between the distal end portion of the driver element 102 and the movable body 103 is increased, and the vibration of the piezoelectric element 100 is driven. It is more reliably propagated to the movable body 103 via 102.

  Next, a method for moving the ultrasonic actuator will be briefly described.

  FIGS. 15, 16, and 17 (a) to 17 (d) are conceptual diagrams for explaining the vibration modes of the piezoelectric elements.

  The wire 104g is connected to the ground, a sine wave reference voltage having a predetermined frequency is applied to the wire 104a, and a voltage whose phase is shifted by 90 ° or −90 ° from the reference voltage is applied to the wire 104b. Then, as shown in FIG. 15, the piezoelectric element 100 is induced with a secondary mode of bending vibration and a primary mode of stretching vibration (so-called longitudinal vibration, also referred to as longitudinal vibration) shown in FIG.

  The resonance frequency of the bending vibration and the resonance frequency of the stretching vibration are determined by the material, shape, etc. of the piezoelectric element 100, respectively. By making these two resonance frequencies substantially coincident and applying a voltage having a frequency in the vicinity thereof, In the piezoelectric element 100, the bending secondary mode and the expansion / contraction primary mode are induced in a harmonic manner, and the shape changes shown in FIGS. 17 (a), 17 (b), 17 (c), and 17 (d) occur in order.

  As a result, the driver element 102 provided in the piezoelectric element 100 causes a substantially elliptical motion when viewed from the paper surface direction. That is, the driver element 102 causes an elliptical motion by combining the bending vibration and the stretching vibration of the piezoelectric element 100. Due to this elliptical motion, the movable body 103 supported by the driver element 102 is driven in the direction of arrow A or arrow B, and serves as an ultrasonic actuator.

  On the other hand, as shown in FIG. 18, there has also been proposed a piezoelectric actuator using a rectangular piezoelectric element 110 and provided with a plurality of substantially hemispherical drivers 112.

For example, Patent Document 1 is known as prior art document information relating to the invention of the present application.
JP 2004-304963 A

  In recent years, along with miniaturization of electronic equipment, the above-described ultrasonic actuator is also required to be miniaturized. However, when the ultrasonic actuator is miniaturized, there is a possibility that efficiency may be reduced.

  That is, the shape of the drive element becomes relatively large in order to ensure the rigidity of the drive element, and in the configuration in which the substantially hemispherical drive element is provided in the antinode portion of the bending vibration of the piezoelectric element as described above, the piezoelectric element In this case, the bending vibration is hindered, and as a result, the efficiency may be reduced.

  Therefore, an object of the present invention is to suppress the inhibition of vibration of a piezoelectric element by a driver, and to improve the efficiency as an ultrasonic actuator.

  In order to achieve this object, an ultrasonic actuator according to the present invention is composed of a piezoelectric element or an actuator main body that includes a piezoelectric element, and that performs a plurality of vibrations with different vibration directions including at least bending vibrations, and A driver that is attached in a point contact shape and / or a line contact shape with respect to a surface of the actuator body that faces the vibration direction of the bending vibration, and outputs a driving force by operating according to the vibration of the actuator body. It is characterized by.

  According to the present invention, it is possible to suppress the driver from inhibiting the bending vibration of the actuator body by reducing the contact portion between the driver and the actuator body as much as possible. As a result, the efficiency as an ultrasonic actuator can be reduced. It can be improved.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

Embodiment 1 of the Invention
FIG. 1 is an exploded perspective view of an ultrasonic actuator according to Embodiment 1 of the present invention, and FIG.

  1 and 2, spherical drivers 2 and 2 are provided at two locations on the surface of the piezoelectric element 1 made of a piezoelectric material such as PZT or quartz.

  The piezoelectric element 1 is provided with a four-part feeding electrode 8 on the front surface and a full-surface electrode (not shown) on the rear surface. A wire 9 is connected to the power supply electrode 8 and the entire surface electrode by solder 6, and the wire 9 is led out through a through hole (not shown) provided in the case 4. When an AC voltage having a specific frequency is applied to the power supply electrode 8 and the entire surface electrode of the piezoelectric element 1 through the wire 9, the piezoelectric element 1 vibrates according to the frequency of the applied voltage. Specifically, the piezoelectric element 1 expands and contracts in the longitudinal direction and flexurally vibrates in the short direction. The piezoelectric element 1 constitutes an actuator body.

  The part of the piezoelectric element 1 where the solder 6 is formed is around the node part of stretching vibration and bending vibration, and the use of this node part as a part for connecting the wire 9 adversely affects the vibration of the piezoelectric element 1. In other words, an unnecessary load on the piezoelectric element 1 due to the formation of the solder 6 is to be suppressed as much as possible.

  The driver elements 2 and 2 are bonded to the piezoelectric element 1 with an adhesive 10. Specifically, as shown in FIGS. 2 and 6, the driver elements 2 and 2 are bonded to a surface facing the vibration direction of the bending vibration in the piezoelectric element 1 (the upper surface of the piezoelectric element 1 in FIGS. 2 and 6). Examples of the material of the driver element 2 include zirconia, alumina, silicon nitride, silicon carbide, tungsten carbide, and the like. The two places where the drive elements 2 and 2 are bonded are places corresponding to the approximate center of the antinode of the flexural vibration of the piezoelectric element 1, and by providing the drive elements 2 and 2 at this place, the vibration of the piezoelectric element 1 is reduced. It can be used more effectively.

  As shown in FIG. 2, the driver elements 2 and 2 are attached in a point contact manner to the upper surface of the piezoelectric element 1 (that is, the surface facing the vibration direction of bending vibration). Here, the “point contact state” is not limited to a state in which the driver 2 and the piezoelectric element 1 are in strict contact with each other, and an adhesive 10 is interposed between the driver 2 and the piezoelectric element 1. It also means a state where the driver 2 and the piezoelectric element 1 are substantially in point contact.

  The adhesive 10 is preferably softer than the piezoelectric element material and the driver element material. Specific examples include synthetic resins, particularly epoxy resins, acrylic resins, and silicone resins. By using such a material, it is possible to realize fixation of each driver element 2 and the piezoelectric element 1 without hindering bending vibration of the piezoelectric element 1 as much as possible.

  The piezoelectric element 1 is accommodated in a case 4, and the piezoelectric element 1 is supported by support bodies 5 </ b> A to 5 </ b> C provided in the case 4. Specifically, the expansion / contraction direction (longitudinal direction) of the piezoelectric element 1 is the same as the movable direction of the movable body 3 (that is, the driving direction in which the driving force of the ultrasonic actuator is output) described later (directions A and B in FIG. 2). The piezoelectric element 1 is disposed in the case 4 so that the wall surfaces 5A and 5C are provided on the inner wall surface of the case 4 in the same direction as the movable body 3. A back support 5B is also provided on the inner bottom surface of the case 4 to support the piezoelectric element 1. That is, both end surfaces of the piezoelectric element 1 in the longitudinal direction are supported by the inner wall surface of the case 4 via the wall surface supports 5A and 5C.

  The back support 5B is provided so that the driver elements 2 and 2 apply pressure to support the movable body 3 described later (that is, abut against the movable body 3), thereby stabilizing the movable body 3. Can be operated. The respective pressures of the two driver elements 2, 2 that support the movable body 3 are set to be substantially the same when no voltage is applied to the power supply electrode 8.

  The wall surface support and the back support are made of an elastic member such as a leaf spring or rubber, and can be provided with a conductive portion 32 as shown in FIG. The lead electrode 37 is provided inside the wall surface of the case 4 and the lead electrode 37 is also provided inside the bottom surface of the case 4, and the feeding electrode ( (Not shown).

  The driver elements 2 and 2 support the movable body 3 (that is, abut against the movable body 3), and each movable element 3 moves substantially elliptically due to the vibration of the piezoelectric element 1 so that the movable body 3 is illustrated. Moves in the A or B direction of 2. That is, the driver elements 2 and 2 output driving force in the directions of arrows A and B while performing an approximately elliptic motion. Further, the vibration direction of the stretching vibration of the piezoelectric element 1 and the moving direction of the movable body 3 are the same direction, the vibration direction of the bending vibration is perpendicular to the movable direction of the movable body 3, and the direction connecting the piezoelectric element 1 and the movable body 3. (That is, the direction in which the driver 2 supports the movable body 3).

  The material of the movable body 3 includes alumina. When alumina is used for the driver 2, it is desirable that the alumina of the movable body 3 is softer than the alumina of the driver 2 from the viewpoint of wear.

  In other words, the ultrasonic actuator configured as described above is supported by the piezoelectric element 1 provided with the feeding electrode 8, the driving elements 2, 2 provided on the surface of the piezoelectric element 1, and the driving elements 2, 2. The piezoelectric element 1 oscillates by combining a plurality of vibrations including at least bending vibrations by supplying power to the power supply electrode 8, and the drivers 2, 2 are driven by the vibrations. The movable body 3 is moved relative to the piezoelectric element 1 by making a substantially elliptical motion, and the driving elements 2 and 2 are substantially spherical and have a vibration direction of bending vibration of the piezoelectric element 1. It is mounted on the surface of the piezoelectric element.

  Next, the operation of the ultrasonic actuator having the above configuration will be described with reference to FIGS.

  By applying an AC voltage having a specific frequency to the specific power supply electrode 8 of the piezoelectric element 1 through the conductive portion 32, the piezoelectric element 1 has the secondary mode of bending vibration shown in FIG. A primary mode of stretching vibration is induced. The resonance frequency of the bending vibration and the resonance frequency of the stretching vibration are determined by the material, shape, etc. of the piezoelectric element, respectively. By making these two frequencies substantially coincident and applying a voltage at a frequency in the vicinity thereof, the piezoelectric element 1, the bending secondary mode and the expansion and contraction primary mode are induced in a harmonic manner, and the shape changes shown in FIGS. 6 (a), (b), (c), and (d) are caused in turn, and as a result, The driving elements 2 and 2 provided in the piezoelectric element 1 cause a substantially elliptical motion when viewed from the paper surface direction. That is, the piezoelectric element 1 performs stretching vibration and bending vibration in the same plane as the paper surface, and as a result, the driver elements 2 and 2 perform substantially elliptical motion in the plane.

  That is, the driving elements 2 and 2 cause an elliptical motion by combining the bending vibration and the stretching vibration of the piezoelectric element 1. The movable body 3 with which the driving elements 2 and 2 abut by this elliptical motion is driven in the direction of arrow A or arrow B in FIG. 2 or FIG. 3, and serves as an ultrasonic actuator.

  Therefore, according to the first embodiment, by making the shapes of the driver elements 2 and 2 spherical, the contact area between each driver element 2 and the piezoelectric element 1 can be reduced, and the bending vibration of the piezoelectric element 1 is inhibited. Can be suppressed. As a result, the efficiency as an ultrasonic actuator can be improved. Here, “spherical” is not limited to a strict spherical shape, but also includes a substantial spherical shape in which the driver 2 is in approximate point contact with the piezoelectric element 1.

<< Embodiment 2 of the Invention >>
Next, an ultrasonic actuator according to Embodiment 2 of the present invention will be described.

  In the first embodiment, each driver element 2 is attached to the piezoelectric element 1 in a point contact manner via the adhesive 10. However, in the ultrasonic actuator according to the second embodiment, as shown in FIG. It is arranged around each driver element 2. That is, the annular body 71 is arranged around the contact point between each driver element 2 and the piezoelectric element 1. That is, each driver element 2 is not only attached to the piezoelectric element 1 in a point contact manner but also attached to the piezoelectric element 1 via the annular body 71. The annular body 71 is attached to the respective driver elements 2 and the piezoelectric elements 1 in line contact. Each driver element 2 and the annular body 71, and the annular body 71 and the piezoelectric element 1 are attached via an adhesive 10. However, each driver element 2 may not be attached in a point contact manner to the piezoelectric element 1 but may be attached only in a line contact manner via the annular body 71. Here, the “line contact state” is not limited to the state in which the annular body 71 and the driver element 2 or the piezoelectric element 1 are in strict contact with each other, but between the annular body 71 and the driver element 2 or the piezoelectric element 1. It also means a state in which the annular body 71 and the driver 2 or the piezoelectric element 1 are substantially in line contact with the adhesive 10 interposed therebetween.

  By disposing the annular body 71 in this way, the respective contact points can be increased between each driver element 2 and the annular body 71, and between the annular body 71 and the piezoelectric element 1, and thereby the driver elements 2, The connection strength between the piezoelectric element 1 and the piezoelectric element 1 can be improved. The annular body 71 is preferably made of a material that is softer than the driver 2 and harder than the adhesive 10 in terms of improving the adhesive strength without preventing vibration. Specifically, it is a metal such as aluminum or iron, or a resin such as epoxy or phenol having high hardness.

  Therefore, according to the second embodiment, the shape of the driver elements 2 and 2 is spherical, and the annular element 71 is interposed between each driver element 2 and the piezoelectric element 1 so that each driver element 2 is connected to the piezoelectric element 1. On the other hand, it is possible to reduce the contact area between each driver element 2 and the piezoelectric element 1 and to prevent the bending vibration of the piezoelectric element 1 from being inhibited. As a result, the efficiency as an ultrasonic actuator can be improved.

<< Embodiment 3 of the Invention >>
Subsequently, an ultrasonic actuator according to Embodiment 3 of the present invention will be described.

  In the first and second embodiments, the spherical shape has been described as the shape of the driver 2, but a cylindrical driver can also be used. In that case, each driver element 2 is disposed so that the axis of the cylinder is substantially orthogonal to a plane in which each driver element 2 moves substantially elliptically (that is, a plane on which the piezoelectric element 1 performs bending vibration), It is mounted on the surface of the piezoelectric element 1 (see FIG. 10). The cross-sectional view at this time is the same as FIG. Further, it is desirable that each cylindrical driver 2 is fixed to the piezoelectric element 1 with the same adhesive 10 as in the spherical shape. Thus, each driver element 2 is attached in line contact with the upper surface of the piezoelectric element 1 (that is, the surface facing the vibration direction of the bending vibration). At this time, the contact portion between each driver element 2 and the piezoelectric element 1 is linear, and the contact portion is located at a position corresponding to the approximate center of the antinode of the flexural vibration of the piezoelectric element 1, and is substantially oval of the driver element 2. It extends so as to be substantially orthogonal to the moving plane. Here, the “line contact state” is not limited to a state in which the driver 2 and the piezoelectric element 1 are in strict contact with each other, and an adhesive 10 is interposed between the driver 2 and the piezoelectric element 1. It also means a state in which the driver 2 and the piezoelectric element 1 are substantially in line contact. In addition, the “cylindrical shape” is not limited to a strict cylindrical shape, but includes a substantial cylindrical shape in which the driver 2 is in approximate line contact with the piezoelectric element 1.

  In other words, the ultrasonic actuator configured as described above is supported by the piezoelectric element 1 provided with the feeding electrode 8, the driving elements 2, 2 provided on the surface of the piezoelectric element 1, and the driving elements 2, 2. The piezoelectric element 1 oscillates by combining a plurality of vibrations including at least bending vibrations by supplying power to the power supply electrode 8, and the drivers 2, 2 are driven by the vibrations. The movable body 3 is moved relative to the piezoelectric element 1 by a substantially elliptical motion. The driver elements 2 and 2 have a substantially cylindrical shape, and the axial direction of the substantially circular cylinder is the driver element. The piezoelectric element 1 is mounted on the surface of the piezoelectric element in the vibration direction of the bending vibration so as to be substantially perpendicular to the surface of the two or two substantially elliptical motions.

  Therefore, according to the third embodiment, by making the shape of the driver elements 2 and 2 cylindrical, the contact area between each driver element 2 and the piezoelectric element 1 is reduced, and the bending vibration of the piezoelectric element 1 is inhibited. The piezoelectric element 1 can be bent by attaching each of the driver elements 2 so that the axis thereof is orthogonal to the plane where the piezoelectric element 1 performs bending vibration. Inhibition of vibration can be further suppressed.

<< Embodiment 4 of the Invention >>
Next, an ultrasonic actuator according to Embodiment 4 of the present invention will be described.

  FIG. 8 is an exploded perspective view of the ultrasonic actuator according to the fourth embodiment, and FIGS. 9 and 10 are ultrasonic actuators according to a modification of the fourth embodiment. The fourth embodiment is different from the first to third embodiments in that a resonator is interposed between the piezoelectric element and the driver. That is, the resonator including the piezoelectric element constitutes the actuator body.

  The ultrasonic actuator shown in FIG. 8 has a configuration in which piezoelectric elements 1b and 1c are fitted in a resonator 1a made of metal or ceramic.

  By applying an alternating voltage of a specific frequency to specific power supply electrodes (not shown) of the piezoelectric elements 1b and 1c in the resonator 1a, the piezoelectric elements 1b and 1c are used as a driving source. A secondary mode of bending vibration shown in FIG. 4 and a primary mode of stretching vibration shown in FIG. 5 are induced.

  Specifically, the piezoelectric elements 1b and 1c are arranged in a state of being eccentric to one side in the short direction of the resonator 1a (that is, a state of being eccentric with respect to the central axis extending in the longitudinal direction). When the piezoelectric elements 1b and 1c arranged in this way are caused to perform stretching vibration, the resonator 1a as a whole stretches and vibrates according to the stretching vibration of the piezoelectric elements 1b and 1c, and the short side of the resonator 1a. The resonator 1a as a whole vibrates and vibrates as the portion eccentric to one side of the direction (the portion where the piezoelectric elements 1b and 1c are disposed) expands and contracts.

  The resonance frequency of the bending vibration and the resonance frequency of the stretching vibration are determined by the material, shape, etc. of the resonator 1a, respectively. The resonator 1a is configured so that these two frequencies substantially coincide with each other, and a voltage having a frequency in the vicinity of the resonator 1a. Is applied to the resonator 1a, and the bending secondary mode and the expansion / contraction primary mode are induced in a harmonic manner, and the resonator 1a is shown in FIGS. 6A, 6B, 6C, and 6D. The shape changes shown in the following are caused in order. As a result, the drive elements 2 and 2 provided in the resonator 1a cause a substantially elliptical motion when viewed from the paper surface direction. That is, the drive elements 2 and 2 cause an elliptical motion by combining the bending vibration and the stretching vibration of the resonator 1a. Due to this elliptical motion, the movable body 3 that comes into contact with the driver elements 2 and 2 is driven in the direction of the arrow A or B in FIG. 2 or FIG. 3, and serves as an ultrasonic actuator.

  By adopting such a configuration, it is possible to reduce the volume of the expensive piezoelectric body, and thus it is possible to configure the ultrasonic actuator at a low cost.

  The ultrasonic actuator shown in FIG. 9 has a structure in which piezoelectric elements 1d, 1e, 1f, and 1g are attached to a resonator 1a made of metal, ceramic, or the like. The ultrasonic actuator having such a configuration can also cause the elliptical motion of the driver elements 2 and 2 by the method as described above, and the movable body 3 can be driven. Since this configuration can also reduce the volume of an expensive piezoelectric body as compared with the first to third embodiments, an ultrasonic actuator can be configured at low cost.

  Further, although the spherical shape has been described as the shape of the driver 2, the columnar driver 2 can be used as shown in FIG. In that case, each driver element 2 is disposed so that the axis of the cylinder is substantially orthogonal to a plane in which each driver element 2 moves substantially elliptically (that is, a plane on which the resonator 1a performs bending vibration). It is mounted in a line contact manner on the surface of the vessel 1a. At this time, the contact portion between each driver element 2 and the resonator 1a is linear, and the contact portion is located at a position corresponding to the approximate center of the antinode of the bending vibration of the resonator 1a, and is substantially oval of the driver element 2. It extends so as to be substantially orthogonal to the moving plane. Further, it is desirable that each cylindrical driver 2 is attached to the resonator 1a with the same adhesive 10 as in the spherical shape. That is, the configuration is the same as that of the third embodiment except that the actuator body is configured by the piezoelectric elements 1b and 1c and the resonator 1a.

  As described above, since the shape of each driver element 2 is spherical or cylindrical, the bending vibration of the resonator 1a can be reduced by reducing the contact portion between each driver element 2 and the resonator 1a as much as possible. Can be prevented, and as a result, the efficiency as an ultrasonic actuator can be improved.

<< Other Embodiments >>
The present invention may be configured as follows with respect to the embodiment.

  That is, in the above-described embodiment, the movable body 3 driven by the driving force of the ultrasonic actuator is a flat plate shape. However, the present invention is not limited to this, and an arbitrary configuration is adopted as the configuration of the movable body. be able to. For example, as shown in FIG. 11, the movable body is a disc body 31 that is rotatable about a predetermined axis X, and the driver elements 2, 2 of the ultrasonic actuator are placed on the side peripheral surface 31 a of the disc body 31. You may be comprised so that it may contact | abut. In the case of such a configuration, when the ultrasonic actuator is driven, the disk body 31 is rotated about a predetermined axis X by the substantially elliptical motion of the driver elements 2 and 2. In addition, as shown in FIG. 12, the movable body is a disc body 32 that can rotate about a predetermined axis X, and the driver elements 2, 2 of the ultrasonic actuator are brought into contact with the flat portion 32 a of the disc body 32. You may be comprised so that it may touch. In such a configuration, when the ultrasonic actuator is driven, the disk body 32 is driven in the tangential direction at the contact portion with the driver elements 2, 2 by the substantially elliptical motion of the driver elements 2, 2. The body 32 is rotated around a predetermined axis X.

  Further, the back supports 5B and 35B are provided on the inner bottom surface of the case 4. However, the back support is provided so that an opening (not shown) is provided on the bottom of the case 4 and the piezoelectric element 1 is supported through the opening. It is also possible to construct a body. In this case, the back surface support body is provided on the mounted body on which the ultrasonic actuator is mounted, and the piezoelectric element is supported from the back surface by mounting the ultrasonic actuator on the mounted body, and via the driver. And presses the movable body. At this time, the back surface support may be formed of an elastic body only in the vicinity of a portion in contact with the piezoelectric element, and the other portion may be formed of an inelastic material.

  In the present embodiment, the vibration mode has been described with the expansion / contraction primary mode and the bending secondary mode, but other modes such as other expansion / contraction primary and bending quaternary modes may be used.

  Further, although all the wall surface supports are elastic bodies, at least one of them may be an elastic body, or only one annular support body is provided so as to penetrate the support body around the piezoelectric element. Similar effects can be obtained by using only the vicinity of the connection with the piezoelectric element as an elastic body.

  In addition, the single plate configuration in which the feeding electrode is formed on the front surface and the back surface of the piezoelectric element has been described, but the same applies to the case of a stacked body in which the electrode and the piezoelectric body are stacked. In that case, elliptical motion can be generated in the driver by applying a voltage to an external electrode connected to a plurality of internal electrodes and formed on an arbitrary surface of the piezoelectric element.

  Further, the configuration of the feeding electrode has been described with the simplest configuration of the four-divided electrode on the front surface and the full-surface electrode on the rear surface. Can be obtained.

  In addition, the above embodiment is an essentially preferable illustration, Comprising: It does not intend restrict | limiting the range of this invention, its application thing, or its use.

<Others>
The ultrasonic actuator described in this specification can also be expressed as follows.

(1) An actuator body configured by a piezoelectric element or including a piezoelectric element and performing a plurality of vibrations having vibration directions different from each other including at least bending vibrations;
And a driver that is attached in a point contact shape and / or a line contact shape to a surface facing the vibration direction of the bending vibration in the actuator main body, and outputs a driving force by operating according to the vibration of the actuator main body. Sonic actuator.

  (2) The ultrasonic actuator according to (1), wherein the driver is attached to the surface of the actuator body via an adhesive.

  (3) The ultrasonic actuator according to (2), wherein the adhesive is softer than the driver and the actuator body.

  (4) The ultrasonic actuator according to (1), wherein the driver is spherical and is attached to the surface of the actuator body in a point contact manner.

(5) further comprising an annular body provided on the surface of the actuator body so as to surround a contact portion between the driver and the surface;
The ultrasonic actuator according to (4), wherein the driver is further attached to the surface of the actuator body via the annular body.

  (6) The ultrasonic actuator according to (5), wherein the driver and the annular body are attached to the surface of the actuator body via an adhesive.

  (7) The ultrasonic actuator according to (6), wherein the annular body is harder than the adhesive.

(8) The actuator body includes the piezoelectric element and a resonator in which the piezoelectric element is disposed and which performs a plurality of vibrations in which vibration directions including at least bending vibration are different from each other,
The ultrasonic actuator according to (1), wherein the driver is spherical and is attached to a surface of the actuator body facing a vibration direction of bending vibration.

  (9) The ultrasonic actuator according to (8), wherein the driver is attached to the surface of the actuator body via an adhesive.

  (10) The ultrasonic actuator according to (9), wherein the adhesive is softer than the driver and the actuator body.

(11) Further comprising an annular body provided on the surface of the actuator body so as to surround a contact portion between the driver and the surface,
The ultrasonic actuator according to (8), wherein the driver is further attached to the surface of the actuator body via the annular body.

  (12) The ultrasonic actuator according to (11), wherein the driver and the annular body are attached to the surface of the actuator body via an adhesive.

  (13) The ultrasonic actuator according to (12), wherein the annular body is harder than the adhesive.

  (14) The ultrasonic actuator according to (1), wherein the driver has a cylindrical shape, and an axis thereof is disposed so as to be orthogonal to a plane on which the actuator body performs bending vibration.

(15) The actuator main body includes the piezoelectric element and a resonator in which the piezoelectric element is disposed and which performs a plurality of vibrations having different vibration directions including at least bending vibration,
The ultrasonic actuator according to (1), wherein the driver has a cylindrical shape, and an axis thereof is arranged so as to be orthogonal to a plane on which the actuator body performs bending vibration.

  (16) The ultrasonic actuator according to (1), wherein the driver is attached to an antinode of bending vibration on the surface of the actuator body.

  (17) The ultrasonic actuator according to (1), wherein the actuator body performs secondary bending vibration and primary longitudinal vibration.

  The ultrasonic actuator of the present invention is characterized in that the driver is mounted in a point contact shape or a line contact shape with respect to the surface of the piezoelectric element in the vibration direction of the bending vibration of the piezoelectric element, and high efficiency is possible. Therefore, it is particularly useful for electronic devices that require high efficiency and downsizing.

FIG. 1 is an exploded perspective view of an ultrasonic actuator according to Embodiment 1 of the present invention. FIG. 2 is a cross-sectional view of the ultrasonic actuator. FIG. 3 is a cross-sectional view of an ultrasonic actuator according to a modification. FIG. 4 is a displacement diagram of a secondary mode of bending vibration. FIG. 5 is a displacement diagram of the primary mode of stretching vibration. 6A to 6D are conceptual diagrams showing the operation of the piezoelectric element of the ultrasonic actuator. FIG. 7 is a cross-sectional view of an ultrasonic actuator according to Embodiment 2 of the present invention. FIG. 8 is an exploded perspective view of an ultrasonic actuator according to Embodiment 4 of the present invention. FIG. 9 is an exploded perspective view of an ultrasonic actuator according to a modification. FIG. 10 is an exploded perspective view of an ultrasonic actuator according to another modification. FIG. 11 is a perspective view of an ultrasonic actuator according to another embodiment. FIG. 12 is a perspective view of an ultrasonic actuator according to another embodiment. FIG. 13 is a perspective view of a piezoelectric element portion of a conventional ultrasonic actuator. FIG. 14 is a cross-sectional view of a conventional ultrasonic actuator. FIG. 15 is a displacement diagram of a secondary mode of bending vibration. FIG. 16 is a displacement diagram of the primary mode of stretching vibration. FIGS. 17A to 17D are conceptual diagrams illustrating the operation of the piezoelectric element. FIG. 18 is a cross-sectional view of a piezoelectric element of a conventional ultrasonic actuator.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 1b, 1c, 1d, 1e, 1f, 1g Piezoelectric element 1a Resonator 2 Driver 3 Movable body 4 Case 5A, 5C Wall surface support body 5B Bottom surface support body 6 Solder 8 Feed electrode 9, 9a, 9b, 9g Wire 10 Adhesive 32 Conductive part 35A, 35C Wall support 35B Bottom support 37 Extraction electrode 71 Ring

Claims (1)

An actuator main body configured with a piezoelectric element or including a piezoelectric element, and performing a plurality of vibrations in which vibration directions including at least bending vibrations are different from each other;
An ultrasonic actuator comprising: a driver that is attached to a surface of the actuator body facing a vibration direction of bending vibration and outputs a driving force by operating according to the vibration of the actuator body.

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