JP2008178209A - Ultrasonic actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ultrasonic actuator capable of obtaining excellent drive performance stably without hindering miniaturization. <P>SOLUTION: The ultrasonic actuator has a vibration body having a displacement portion which is expanded or contracted by electrical signals and contact portions to which elliptical motion is caused by the expansion and contraction of the displacement portion, guide members which cause relative movement to the vibration body by a friction force generated by the contact with the contact portions and the elliptical motion, and a pressure member which brings the guide members contact into contact with portions by pressure. In this actuator, the guide members and the pressure member are formed integrally. The pressure member is made of a high-polymer material having the Young's modulus of 0.1 GPa or larger. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an ultrasonic actuator, and more particularly, to an ultrasonic actuator that generates a relative movement by bringing a vibrating body into pressure contact with a driven body.

  In the past, attempts have been made to use ultrasonic actuators in various mobile devices. An ultrasonic actuator is generally composed of a vibrating body including a piezoelectric element that is an electro-mechanical energy conversion element, a driven body (moving body) that contacts the vibrating body in a pressurized state, and the like. The ultrasonic actuator is brought into pressure contact with the vibrating body by inputting a drive signal to the vibrating body, causing the vibrating body to expand and contract, and causing part of the vibrating body to perform elliptical vibration (hereinafter, including circular vibration). A relative motion is generated between the driven body and the driven body by a frictional force.

  Since the ultrasonic actuator is small and excellent in quietness, it has been used as a drive device for electronic equipment such as an electronic camera, and its application is expanding further.

  As a traveling mechanism in the ultrasonic actuator having such a configuration, a linear drive parallel guide system is usually used.

  For example, a pair of parallelly arranged guides (driven bodies) that hold an ultrasonic transducer (vibrating body), and an ultrasonic transducer and a guide that are disposed and housed on both side surfaces of the pair of guides, A traveling mechanism composed of a leaf spring or the like that urges the guide to press at a predetermined pressure (see Patent Document 1).

In addition, a travel mechanism (provided with a coil spring that urges one of a pair of guide shafts arranged in parallel to press the vibrator (vibrating body) and the guide shaft (driven body) with a predetermined pressure. Patent Document 2) is known.
JP 2004-104984 A JP 2005-57837 A

  However, in the ultrasonic actuator disclosed in Patent Document 1, a leaf spring is disposed between a pair of parallel guides, and an ultrasonic transducer is sandwiched therebetween.

  In such a configuration, since the material of the guide is metal (aluminum), the vibration of the ultrasonic vibrator becomes an excitation force, and unnecessary vibration such as natural vibration may be excited in the guide. Metals, especially aluminum, tend to vibrate because of their low loss factor. When unnecessary vibration is excited, depending on the frequency and phase relationship between the elliptical vibration of the ultrasonic vibrator and the vibration of the guide, the transmission efficiency of the elliptical vibration is greatly reduced, leading to a reduction in thrust and generation of abnormal noise. There is a fear.

  In addition, vibration is transmitted to a device incorporating a leaf spring or an ultrasonic actuator through a guide, and there is a risk of causing wear or abnormal noise.

  Here, the influence of the unnecessary vibration on the driving performance will be described with reference to FIG. FIG. 8A shows a case where unnecessary vibration is not generated in the driven body, and FIG. 8B shows a case where the driving frequency of the vibrating body matches the natural vibration frequency of the driven body. These are the schematic diagrams which show the mode of a drive in case the natural vibration frequency of a to-be-driven body is lower than the drive frequency of a vibration body.

  In the case of FIG. 8A, the contact portion provided on the vibrating body performs elliptical motion, and transmits driving force by frictional force at the time of contact while repeating contact / detachment with the driven body.

  However, the driven body is vibrated by the collision of the contact portion, and the driven body is excited by the natural vibration depending on the relationship between the collision cycle (the driving frequency of the vibrating body) and the natural vibration frequency of the driven body. There is. The natural vibration is based on the size, shape, and material of the driven body. As the driven body is reduced in size, length, and complexity, the number of modes increases and the vibration form becomes complicated.

  When natural vibration is excited in the driven body and the driving frequency of the vibrating body and the natural vibration frequency of the driven body coincide with each other, as shown in FIG. It vibrates (deforms) in synchronization with elliptical vibration. For this reason, even when the abutting part moves in the counter driving direction, it cannot be detached from the driven body, the driving force acts on the driven body to act as a brake, and the driving state becomes unstable as the output decreases.

  In addition, when the natural vibration frequency of the driven body is lower than the driving frequency of the vibration body, as shown in FIG. Becomes irregular. For this reason, the contact portion cannot contact the driven body at every vibration cycle (missing), resulting in a decrease in output and generation of abnormal noise.

  Further, the ultrasonic actuator disclosed in Patent Document 2 presses the movable guide shaft inserted into the elongated hole to the fixed guide shaft by a coil spring, and holds the vibrator.

  In such a configuration, in order to smoothly move the movable guide shaft up and down, some backlash is required in the moving direction of the vibrator. When the vibrator vibrates elliptically, the driving force is obtained by the reaction force from the guide shaft that is in contact with it, and it will self-run. The movable-side guide shaft moves by the corresponding amount. During this time, no driving force can be obtained from the movable guide shaft, and the thrust of the vibrator is halved, so that the activation is delayed and the responsiveness is lowered. In addition, there is a risk of generating sound accompanying the movement of the movable guide shaft.

  In addition, there is a problem that a housing for holding the guide shaft and the coil spring is required, which hinders downsizing of the apparatus.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an ultrasonic actuator capable of stably obtaining excellent driving performance without inhibiting downsizing.

  The above object is achieved by the invention described in any one of the following items 1 to 3.

1. A displacement part that expands and contracts by an electrical signal;
A contact portion that generates an elliptical motion by expansion and contraction of the displacement portion;
A guide member that comes into contact with the abutting portion and causes relative movement with respect to the vibrating body by a frictional force generated by the elliptical motion;
A pressurizing member that pressurizes and contacts the guide member and the contact portion;
In an ultrasonic actuator having
The guide member and the pressure member are integrally formed,
The ultrasonic actuator according to claim 1, wherein the material of the pressure member is a polymer material having a Young's modulus of 0.1 GPa or more.

  2. 2. The ultrasonic actuator according to 1, wherein the rigidity of the pressure member is lower in the pressure direction than the relative movement direction of the vibrating body with respect to the guide member.

  3. 3. The ultrasonic wave according to claim 1, wherein the pressurizing member has a restricting portion that restricts swinging of the vibrating body in a direction perpendicular to a direction of relative movement of the vibrating body with respect to the guide member. Actuator.

  According to the present invention, the guide member and the pressure member are integrally formed, and a polymer material having a Young's modulus of 0.1 GPa or more is used as the material of the pressure member. That is, since the pressure member is made of a resin material, when the vibration of the vibrating body becomes an excitation force and unnecessary vibration starts to occur in the guide member, vibration energy is generated by the viscoelasticity of the resin material against vibration (deformation). Is converted into thermal energy, and unnecessary vibration is attenuated. Further, since the guide member and the pressure member are integrally formed, mutual adhesion can be secured, so that a great vibration damping effect can be obtained.

  In this way, by suppressing unnecessary vibration of the guide member, the transmission efficiency of elliptical vibration (hereinafter also referred to as elliptical motion) is increased, and the driving performance and stability can be improved. Moreover, the generation of abnormal noise can be prevented.

  Embodiments of an ultrasonic actuator according to the present invention will be described below with reference to the drawings. In addition, although this invention is demonstrated based on embodiment of illustration, this invention is not limited to this embodiment.

Embodiment 1
Initially, the structure of the ultrasonic actuator 1 by Embodiment 1 is demonstrated using FIG. FIG. 1A is a front view showing an outline of the overall configuration of the ultrasonic actuator 1, FIG. 1B is a side view, and FIG. 1C is a view from the AA ′ direction in FIG. FIG.

  As shown in FIG. 1A, the ultrasonic actuator 1 includes a vibrating body 10, guide members 21, 22, a pressure member 30, and the like.

  The vibrating body 10 is disposed between the two guide members 21 and 22, and the guide member 21 is connected to the guide member 21 at the one end portion in the longitudinal vibration direction, which will be described later, and the other end. The abutting portion 104 provided in the portion abuts on the guide member 22. The vibrating body 10 expands and contracts by a drive signal applied by a drive circuit (not shown), and the contact portions 105 and 106 and the contact portion 104 perform elliptical vibrations in opposite directions to each other. , And the guide members 21 and 22 that are in pressure contact with the contact portion 104, respectively, to perform relative movement by frictional force.

  As shown in FIG. 1A, the guide member 21 partially protrudes in the lateral direction, and is incorporated and fixed to the apparatus with the protrusions 21a and 21b as a reference. As the vibrating body 10 moves, the guide member 22 is slightly inclined. However, since the contact portion 104 is located between the contact portions 105 and 106 with respect to the moving direction, the guide member 21 is vibrated. The posture of the body 10 does not always change, and highly accurate position control and speed control can be performed.

  The guide members 21 and 22 are long parts having a circular or quadrangular cross-sectional shape, and a metal part such as stainless steel that is inexpensive and easy to manufacture is used as the material. The surface is subjected to surface hardening treatment such as quenching and nitriding treatment in order to prevent abrasion with the vibrating body 10. Ceramic coating such as CrN or TiCN may be performed. Moreover, wear resistance can be further improved by using ceramics, such as an alumina and a zirconia.

  A pressure member 30 is coupled to the guide members 21 and 22 to bring the vibrating body 10 into pressure contact with the guide members 21 and 22. At both ends of the pressure member 30, spring constituent portions 30a are provided, and the vibrating body 10 is sandwiched with a predetermined amount of force by the elasticity of the spring constituent portions 30a.

  As shown in FIG. 1B, the spring constituting portion 30a is a spring mechanism formed in a rhombus shape, and generates elastic force by deformation of the central bending portion 30a1 and bending deformation of the arm portion 30a2. A predetermined force is applied to 10. With such a configuration, the spring constant in the pressurizing direction (arrows H1 and H2 directions) can be reduced, so that manufacturing errors and variations in pressure applied to the vibrating body 10 due to the position of the vibrating body 10 can be reduced. Can do. Further, as shown in FIG. 1A, the guide member accompanying the movement of the vibrating body 10 is obtained by increasing the width W of the spring component 30a, that is, the dimension in the moving direction of the vibrating body 10 and increasing the rigidity. A lateral shift or the like between 21 and 22 can be prevented.

  Note that the spring component 30a is not limited to two locations, and may be provided in three or more locations, and it is not necessary that they are connected. Further, the configuration is not limited to the rhombus shape, and any configuration is possible as long as the rigidity in the moving direction of the vibrating body 10 is high and the spring constant in the pressurizing direction (arrow H1, H2 direction) can be reduced.

  Here, a method of connecting the vibrating body 10 and the lens block 60 when, for example, the lens block 60 is driven using the ultrasonic actuator 1 will be described with reference to FIG. FIG. 2 shows an example of a method of coupling the vibrating body 10 and the lens block 60, and is a plan sectional view as seen from the BB ′ direction in FIG.

  The lens block 60 moves along a guide member (not shown), and sandwiches the vicinity of the center in the vertical direction of the vibrating body 10 by the two leaf springs 50 fixed to the lens block 60. As the vibrating body 10 moves, a driving force is transmitted to the lens block 60 via the leaf spring 50. The strength of the leaf spring 50 is set to a strength that does not inhibit the vibration of the vibrating body 10. In order to prevent wear between the leaf spring 50 and the vibrating body 10, the leaf spring 50 and the vibrating body 10 may be fixed with a soft adhesive such as rubber.

  Next, the configuration of the vibrating body 10 will be described with reference to FIG. FIG. 3A is a front view showing the configuration of the vibrating body 10, and FIG. 3B is a side view.

  As shown in FIG. 3A, the vibrating body 10 includes a piezoelectric displacement portion 101, weight members 102 and 103, contact portions 104, 105, and 106.

  The piezoelectric displacement portion 101 corresponds to a displacement portion in the present invention, and is displaced by power supply from a drive circuit (not shown), and further resonates with the displacement as an excitation force to generate elliptical vibration. The weight members 102 and 103 are provided at both ends of the piezoelectric displacement portion 101, and expand the vibration amplitude at the time of resonance. The contact portions 105 and 106 and the contact portion 104 are in contact with the above-described guide members 21 and 22, respectively, and transmit elliptical vibrations to the guide members 21 and 22 by a frictional force.

  Here, the structure of the piezoelectric displacement part 101 is demonstrated using FIG. FIG. 4 is a plan sectional view showing the internal electrode configuration of the piezoelectric displacement portion 101 and viewed from the CC ′ direction in FIG.

  The piezoelectric displacement portion 101 includes a rectangular piezoelectric ceramic thin plate (hereinafter also referred to as a piezoelectric thin plate) having piezoelectric characteristics such as PZT, internal electrodes a2 and b2 shown in FIG. 4A, and an internal electrode shown in FIG. a1 and b1 are alternately stacked. Further, the internal electrodes a2 and b2 and the internal electrodes a1 and b1 are divided into two on the left and right sides of the vibrating body 10.

  External electrodes A1 and B1 and external electrodes A2 and B2 are provided on the front surface and the back surface of the vibrating body 10, respectively, and are connected to the internal electrodes a1 and b1 and the internal electrodes a2 and b2 protruding from the end surfaces. Also, lead wires and FPC (flexible printed wiring board) (not shown) are connected to the external electrodes A1 and B1 and the external electrodes A2 and B2, and are connected to a drive circuit.

  The piezoelectric thin plate is polarized in the same direction through the external electrodes A1 and A2 and the external electrodes B1 and B2 in the internal electrode a1-a2 direction and the internal electrode b1-b2 direction.

  When a voltage of the same polarity (for example, A1 = B1 = 0V, A2 = B2 = 10V) is applied between the external electrodes A1-A2 and the external electrodes B1-B2, all the piezoelectric thin plates expand (or contract), and as a whole Stretch (or shrink). Further, when a voltage of opposite polarity (for example, A1 = B2 = 10V, A2 = B1 = 0V) is applied between A1 and A2 and between the external electrodes B1 and B2, the left half of the piezoelectric thin plate expands (or contracts), and the right Half is shrunk (or stretched), and bending deformation occurs in the piezoelectric portion as a whole.

  Returning to FIG. 3, the weight members 102 and 103 are fixed to both ends of the piezoelectric displacement portion 101 in the stacking direction by an adhesive having a relatively high elastic modulus such as epoxy, and expands the vibration amplitude at the time of resonance. As the material of the weight members 102 and 103, a material having a large specific gravity is effective. Therefore, tungsten (specific gravity ≈ 19), tungsten alloy using nickel, copper, iron, or the like as a binder (specific gravity ≈ 18), tungsten carbide super A hard alloy (specific gravity ≈ 15), a tungsten resin (specific gravity ≈ 10 to 13) in which tungsten powder and a resin are combined, or the like is used.

  The piezoelectric displacement portion 101 is manufactured by stacking in units of blocks sufficiently larger than the vibrating body 10 and then cutting out to the size of the vibrating body 10 with a dicer or the like. In addition, since the weight members 102 and 103 are also laminated and bonded at the same time in the laminating process, it is not necessary to perform the pasting work for each vibrating body, so that the manufacturing process can be greatly simplified and the cost can be reduced. it can.

  As the material of the contact portions 104, 105, 106, cemented carbide, ceramics such as alumina and zirconia are used in order to prevent wear. The contact portion 104 and the contact portions 105 and 106 are fixed to the weight members 103 and 102, respectively, using an adhesive having a relatively high elasticity such as epoxy.

  Here, the elliptical vibration excited by the vibrating body 10 having such a configuration will be described with reference to FIG. The vibrating body 10 is driven using resonance. FIG. 5 shows a state of deformation of the vibrating body 10 by the natural mode used for resonance driving. FIG. 5A shows a longitudinal (stretching) primary vibration mode, and FIG. 5B shows a bending primary vibration mode. is there.

  In the longitudinal primary vibration mode, as shown in FIG. 5A, stretching vibration is performed with the central portion P of the vibrating body 10 as a node, and the contact portions 104 to 106 are displaced in the longitudinal direction (Y direction). In the bending primary vibration mode, as shown in FIG. 6B, the first bending deformation is performed with the nodes P1 and P2 as nodes, and the tips of the contact portions 104 to 106 are in the lateral direction (X direction). It is displaced to.

  The longitudinal primary vibration mode can be excited by applying a drive signal having the same phase between the external electrodes A1 and A2 and between the external electrodes B1 and B2 at the resonance frequency. The bending primary vibration mode can be excited by applying a drive signal having an opposite phase between the external electrodes A1 and A2 and between the external electrodes B1 and B2 at the resonance frequency.

  By substantially matching these two modes and applying a drive signal having a phase difference of 90 degrees between the external electrodes A1 and A2 and between the external electrodes B1 and B2 at the resonance frequency, both modes are excited and the vibrating body Elliptical vibrations are generated at both ends of 10. When a drive signal having a phase advanced by 90 degrees with respect to the space between the external electrodes B1 and B2 is applied between the external electrodes A1 and A2, the end surfaces of the contact portions 104 are counterclockwise and end surfaces of the contact portions 105 and 106 Is excited by an elliptical vibration that rotates clockwise. When the phase of the drive signal to be applied is reversed (-90 degrees), the rotational direction of the elliptical vibration at each contact point is reversed.

  In the ultrasonic actuator 1 having such a configuration, the present invention efficiently suppresses unnecessary vibrations such as natural vibrations excited by the guide members 21 and 22 by the excitation force of the vibrating body 10. Details will be described below.

  As shown in FIG. 1A, the pressurizing member 30 is coupled over substantially the entire length of the guide members 21 and 22 and is made of a resin material having a large loss coefficient. When the vibration of the vibrating body 10 becomes an excitation force and unnecessary vibrations start to occur in the guide members 21 and 22, the vibration energy is converted into thermal energy by the viscoelasticity of the resin material against vibration (deformation), thereby unnecessary vibrations. Is attenuated.

  For the material of the pressure member 30, a material having a small loss factor (less than 0.01) such as metal is not suitable, and a material having a large loss factor is preferable. However, in experiments, Young's modulus of rubber or the like is small (0. Less than 1 GPa) The relatively soft material had a small damping effect. Rubber generally has a large loss factor and exhibits a large damping effect for vibrations at relatively low frequencies, but is less effective for minute vibrations of several tens of kHz or more like an ultrasonic actuator.

  Therefore, the material of the pressure member 30 is preferably a resin material having a loss factor of 0.01 or more and a Young's modulus of 0.1 GPa or more, exhibiting good spring properties, and being strong against impacts such as PC (polycarbonate) and POM (polyacetal). ) Etc. are used.

  In addition, the guide members 21 and 22 and the pressure member 30 can be easily manufactured by being integrally molded by insert molding or the like, and can ensure mutual adhesion. It can be demonstrated. In addition, you may couple | bond the guide members 21 and 22 and the pressurization member 30 with adhesive agents, such as an epoxy.

  Further, as shown in FIG. 1C, the pressurizing member 30 corresponds to a regulating portion in the present invention for regulating swinging of the vibrating body 10 in a direction perpendicular to the traveling direction of the vibrating body 10. Side walls 30b and 30c are integrally formed.

  As described above, in the ultrasonic actuator 1 according to the first embodiment of the present invention, the guide members 21 and 22 and the pressure member 30 are integrally formed, and the loss coefficient of the material of the pressure member 30 is 0. A polymer material having a coefficient of 01 or higher and a Young's modulus of 0.1 GPa or higher was used. That is, since the pressurizing member 30 is made of a resin material having a large loss coefficient, when the vibration of the vibrating body 10 becomes an excitation force and unnecessary vibration starts to occur in the guide members 21 and 22, the vibration (deformation) is not affected. The vibration energy is converted into heat energy by the viscoelasticity of the resin material, so that unnecessary vibration is attenuated. Moreover, since the guide members 21 and 22 and the pressurizing member 30 are integrally formed, mutual adhesion can be ensured, so that a great vibration damping effect can be obtained.

  In this way, by suppressing unnecessary vibrations of the guide members 21 and 22, the transmission efficiency of the elliptical vibration is increased, and the driving performance and stability can be improved. Moreover, generation | occurrence | production of unusual noise can be prevented. Furthermore, it is possible to prevent transmission of vibrations to the apparatus in which the ultrasonic actuator 1 is incorporated, and to prevent generation of abnormal noise or wear in the apparatus.

  Further, by forming the guide members 21 and 22 and the pressure member 30 integrally, the size of the ultrasonic actuator 1 and the manufacturing process can be simplified. Further, a housing as in the case of the above-mentioned Patent Document 2 is unnecessary, and the size can be further reduced.

  Further, since the spring component 30a can reduce the spring constant in the pressurizing direction (arrow H1, H2 direction), the manufacturing error and the variation in the applied pressure to the vibrating body 10 due to the position of the vibrating body 10 are reduced. can do. Further, the width dimension W of the spring component 30a, that is, the dimension in the moving direction of the vibrating body 10 is sufficiently increased to increase the rigidity, thereby preventing the lateral displacement between the guide members 21 and 22 due to the movement of the vibrating body 10. can do. Thereby, while improving the responsiveness at the time of starting, since the change of the pressing force accompanying the movement of the vibrating body 10 can be made small, drive stability can be improved.

  Further, the pressing member 30 is provided with side walls 30b and 30c for restricting the swinging of the vibrating body 10 in the direction perpendicular to the traveling direction of the vibrating body 10. Thereby, since it is not necessary to give the function to the guide members 21 and 22 and the vibrating body 10, it is possible to simplify the shapes of the guide members 21 and 22 and the contact portions 104, 105, and 106 of the vibrating body 10. it can. Moreover, since the material of the pressurizing member 30 is resin, it can be easily manufactured by injection molding without increasing the cost.

[Embodiment 2]
Next, the ultrasonic actuator 1 according to the second embodiment will be described. The configuration of the main part is substantially the same as that of the ultrasonic actuator 1 according to the first embodiment described above, and detailed description thereof will be omitted. A vibrating body having a configuration different from that of the first embodiment will be described. In the ultrasonic actuator 1 according to the first embodiment, a rectangular vibrating body is used. However, in the case of the second embodiment, a truss-type vibrating body is used.

  Initially, the structure of the ultrasonic actuator 1 by Embodiment 2 is demonstrated using FIG. 6A is a front view showing an outline of the overall configuration of the ultrasonic actuator 1, FIG. 6B is a side view, and FIG. 6C is a view from the AA ′ direction in FIG. 6A. FIG.

  As shown in FIG. 6A, the ultrasonic actuator 1 includes a vibrating body 10, guide members 21, 22, a pressure member 30, a holding plate 40, a roller 45, and the like.

  As shown in FIG. 6A, the vibrating body 10 includes two piezoelectric displacement portions 101, a contact portion 104, a base member 108, and the like, and the contact portion 104 is attached to one end of the piezoelectric displacement portion 101 as an adhesive. Etc. are joined together. On the other hand, the base member 108 is joined to the other end of the piezoelectric displacement portion 101 with an adhesive or the like. As the adhesive, an epoxy adhesive having high adhesive strength and high rigidity is used.

  The two piezoelectric displacement portions 101 are arranged at approximately 90 degrees with the contact portion 104 interposed therebetween, and are integrally formed in a dogleg shape. Note that the vibrator 10 having such a configuration conforms to a truss-type vibrator disclosed in, for example, Japanese Patent Application Laid-Open No. 2000-358387, and a detailed description thereof will be omitted.

  Since the truss-type vibrating body 10 is a type in which one portion, that is, one abutting portion 104 performs elliptical vibration, the guide member in contact with the vibrating body 10 is only the guide member 22.

  As shown in FIG. 6B, the vibrating body 10 is fixed to a holding plate 40 provided on the back surface thereof via a base member 108. The holding plate 40 is provided with a roller 45 for reducing movement resistance when the guide member 21 pressurizes and holds the vibrating body 10, or a bearing (not shown).

  The guide member 22 contacts the contact portion 104 of the vibrating body 1, and the guide member 21 contacts the roller 45. Note that the roller 45 may directly roll the pressure member 30 without providing the guide member 21.

[Embodiment 3]
Next, the ultrasonic actuator 1 according to Embodiment 3 will be described. In the ultrasonic actuator 1 according to the first embodiment and the second embodiment, the vibrating body 10 sandwiched between a pair of guide members 21 and 22 arranged in parallel is provided along the guide members 21 and 22. This is a so-called linear drive parallel guide system that moves linearly. On the other hand, in the case of the third embodiment, the vibrating body 10 swings (turns) along the guide members 21 and 22 having an arc shape.

  Initially, the structure of the ultrasonic actuator 1 by Embodiment 3 is demonstrated using FIG. FIG. 7 is a front view showing an outline of the overall configuration of the ultrasonic actuator 1.

  As shown in FIG. 7, the ultrasonic actuator 1 includes two vibrators 10, guide members 21 and 22, a pressure member 30, and the like.

  The vibrating body 10 is a truss-type vibrating body used in the second embodiment. As shown in FIG. 7, the bases 108 provided on the respective vibrating bodies 10 face each other and are coupled to a holding plate (not shown).

  The guide members 21 and 22 have long parts such as a circular shape or a quadrangular shape in cross section when viewed from the front.

  At the periphery of the guide members 21 and 22, a pressurizing member 30 having a circular shape in front view that couples the two vibrating bodies 10 to the guide members 21 and 22 in pressure contact is coupled. A spring component 30a is provided on the left and right sides of the pressure member 30, and the vibrating body 10 is sandwiched with a predetermined amount of force by the elasticity of the spring component 30a in the direction of the arrow H3.

  The vibrating body 10 is expanded and contracted by a drive signal applied by a drive circuit (not shown), and the two abutting portions 104 are elliptically vibrated in the same direction, thereby being brought into pressure contact with the two abutting portions 104, respectively. The guide members 21 and 22 are swung (rotated) in the directions of arrows P and Q by a frictional force. The vibrating body 10 may be fixed to a housing (not shown) and the guide members 21 and 22 may be swung (turned).

1 is an overall configuration diagram of an ultrasonic actuator according to Embodiment 1 of the present invention. 6 is a diagram illustrating an example of a method for coupling a vibrating body and a lens block according to Embodiment 1. FIG. 5 is a diagram illustrating a configuration of a vibrating body according to Embodiment 1. FIG. FIG. 3 is a diagram illustrating an internal electrode configuration of a piezoelectric displacement unit according to Embodiment 1. FIG. 6 is a diagram illustrating a state of deformation in the natural mode of the vibrator according to the first embodiment. It is a whole block diagram of the ultrasonic actuator by Embodiment 2 of this invention. It is a whole block diagram of the ultrasonic actuator by Embodiment 3 of this invention. It is a schematic diagram which shows the mode of the drive by elliptical vibration.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ultrasonic actuator 10 Vibrating body 101 Piezoelectric displacement part 102,103 Weight member 104,105,106 Contact part 108 Base member 21,22 Guide member 30 Pressure member 40 Holding plate 45 Roller 50 Leaf spring 60 Lens block A1, A2 , B1, B2 External electrode a1, a2, b1, b2 Internal electrode

Claims (3)

A displacement part that expands and contracts by an electrical signal;
A contact portion that generates an elliptical motion by expansion and contraction of the displacement portion;
A guide member that comes into contact with the abutting portion and causes relative movement with respect to the vibrating body by a frictional force generated by the elliptical motion;
A pressurizing member that pressurizes and contacts the guide member and the contact portion;
In an ultrasonic actuator having
The guide member and the pressure member are integrally formed,
The ultrasonic actuator according to claim 1, wherein the material of the pressure member is a polymer material having a Young's modulus of 0.1 GPa or more. The ultrasonic actuator according to claim 1, wherein rigidity of the pressure member is lower in a pressure direction than a relative movement direction of the vibrating body with respect to the guide member. 3. The super press according to claim 1, wherein the pressure member has a restricting portion that restricts swinging of the vibrating body in a direction perpendicular to a direction of relative movement of the vibrating body with respect to the guide member. Sonic actuator.

Images