JP2019088183A - Vibration wave motor, drive control system, optical device and electronic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vibration wave motor which suppresses generation of unnecessary traveling waves and unnecessary standing waves while exhibiting a sufficient driving speed.
SOLUTION: The vibration wave motor is provided with a moving body, a vibrator having an annular diaphragm and an annular piezoelectric element, and a vibration damping member in order, and the vibration plate is provided on the side of the moving body. A plurality of grooves extending radially from the center of the annular diaphragm, wherein at least one of the plurality of grooves has a different depth and is unevenly pressurized by the vibration damping member A vibration wave motor characterized by
[Selected figure] Figure 1

Description

  The present invention relates to a vibration wave motor, and a drive control system, an optical apparatus and an electronic apparatus using the same.

  The vibration type (oscillation wave) actuator has a vibrator constituted by an electromechanical energy conversion element such as a piezoelectric element and the like and an elastic body, and a moving body in pressure contact with the vibrator. The vibration-type actuator is utilized as a vibration wave motor that relatively moves a moving body by using friction generated by a driving force of vibration excited in a vibrator.

  The structure and driving principle of an annular vibration wave motor, which is a typical application of a vibration type actuator, will be shown below. In the following, when referring to “annular ring”, the form of the article or member can be regarded as a form in which a disc having a predetermined thickness has a concentric through hole. Hereinafter, the "thickness" of the disc and the two surfaces that determine the thickness of the disc with respect to the direction along the through hole will be called "surface".

  The annular vibration wave motor includes an annular vibrator and an annular moving body brought into pressure contact with the vibrator by a pressure member. A vibration damping member is provided between the vibrator and the pressure member so as to prevent the vibration of the vibrator from being transmitted to the pressure member.

  The moving body is made of an elastic body, and the material is generally metal. The vibrator includes an annular diaphragm and an annular piezoelectric element provided on one surface thereof. The diaphragm is made of an elastic material, and the material is generally metal. The piezoelectric element is an electrode divided into a plurality of regions obtained by equally dividing the circumference by n along the circumferential direction of the annular ring on one surface of an annular piezoelectric material (piezoelectric ceramic) (n is a natural number) And one common electrode on the other side. The circumferential length is represented by nλ in units of the length λ. The material of the piezoelectric ceramic is generally a lead zirconate titanate based material.

  The electrodes divided into the plurality of regions are respectively provided in two regions constituting the driving phase electrode, at least one region constituting the detection phase electrode, and a region constituting the non-driving phase electrode provided as needed. It is provided.

  Polarization is applied to the two drive phase electrodes by alternately applying electric fields in opposite directions at a pitch of λ / 2 along the circumferential direction. Therefore, the expansion / contraction polarity of the piezoelectric ceramic is alternately reversed at a pitch of λ / 2 with respect to the applied voltage. Furthermore, non-driving phase electrodes short-circuited with the common electrode are provided in two regions (spaces) separating the two regions constituting the respective driving phase electrodes by an odd number multiple of λ / 4. At this interval, usually, a detection phase electrode to be described later is provided.

  When an alternating voltage is applied to the drive phase electrode of such a vibration wave motor, a first standing wave and a second standing wave of wavelength λ are generated over the entire circumference of the vibrator. The second standing wave is rotationally moved by λ / 4 in the circumferential direction with respect to the first standing wave.

  On the other hand, when two types of alternating voltages having the same frequency and a temporal phase difference of π / 2 are applied to the respective drive phase electrodes, the standing waves of the two are synthesized. As a result, in the vibrator, a traveling wave (wave number n along an annular ring, wavelength λ) of bending vibration (a vibration whose amplitude is perpendicular to the plane of the vibrator) advancing in the circumferential direction around the entire circumference is generated Do.

  A moving body in contact with a surface where a traveling wave of bending vibration (hereinafter simply referred to as “bending vibration wave”) is generated is driven by receiving frictional force (driving force) in the circumferential direction from the diaphragm.

  However, a bending vibration wave different from the n-th (wave number n) preset in driving may be generated, for example, a traveling wave of (n-1) -th order or (n + 1) -th order bending vibration. These bending vibration waves out of the setting are called unnecessary traveling waves. The cause of generation of the unnecessary traveling wave is the low precision of the contact surface of the vibrator and the moving body, the unevenness of mechanical vibration generated in the moving body, and the non-uniform distribution of the contact pressure of the vibrator and the moving body . When the unnecessary traveling wave is generated when the vibration wave motor is driven, it causes an abnormal noise and an output decrease due to the unnecessary traveling wave.

  Therefore, as a means for reducing the generation of the unwanted traveling wave, Patent Document 1 discloses that grooves are formed radially on the surface of the diaphragm in contact with the annular moving body, and the depth of the grooves is sinusoidal An arrangement is disclosed that varies along a curve. With the configuration as described in Patent Document 1, unnecessary traveling waves (unnecessary traveling waves) are suppressed when the groove depth changes along a sine wave curve.

  However, when the groove depth is changed as described above, the diaphragm thickness in the portion where the groove depth is large is relatively reduced. Therefore, the vibration amplitude of the standing wave is increased such that the portion where the depth of the groove is large matches the abdomen. Such a standing wave (unnecessary standing wave) has no contribution to the rotation of the oscillatory wave motor, and causes the generation of abnormal noise and the reduction of the output.

  On the other hand, Patent Document 2 uses a separated support member for the purpose of stably fixing the vibrator, but because the depth of the groove is not changed along the sine wave curve, Although unnecessary standing waves are not generated, unnecessary traveling waves are easily generated. Moreover, there is no description about which position in the circumferential direction of the vibrator is provided for the support member.

Patent No. 5322431 JP-A-6-153541

  The present invention has been made to address the above-mentioned problems, and provides an oscillatory wave motor which exhibits a sufficient driving speed and in which the generation of the unnecessary traveling wave and the unnecessary standing wave are both suppressed, and the same. A drive control system and an optical apparatus are provided.

The oscillatory wave motor of the present invention for solving the above problems is:
Mobile and
A vibrator having an annular diaphragm and an annular piezoelectric element;
A vibration damping member,
Are vibration wave motors provided in order, and
The diaphragm is on the movable body side,
It has a plurality of grooves extending radially from the center of the annular diaphragm,
At least one of the plurality of grooves has a different depth,
The drive control system of the present invention for solving the above-mentioned problem is characterized by including the above-mentioned vibration wave motor.

  An optical apparatus according to the present invention for solving the above-mentioned problems is characterized by comprising the drive control system.

  An electronic device according to the present invention for solving the above-mentioned problems is characterized by comprising the above-mentioned vibration wave motor.

  According to the present invention, in the vibration wave motor or the drive control system using the vibration wave motor, the optical device and the electronic device, the generation of the unnecessary traveling wave and the unnecessary standing wave is effective while exhibiting a sufficient driving speed. Can be suppressed.

1 is a schematic view showing an embodiment of a vibration wave motor according to the present invention. It is a cross-sectional schematic diagram which extracts and shows a part of structure of one Embodiment of the vibration wave motor of this invention. It is the schematic which shows the relationship between the circumference length and the wavelength of a vibration wave in the annular | circular shaped piezoelectric element used for the vibration wave motor of this invention, and a vibrator | oscillator. For convenience of explanation, the display of the electrodes is omitted. It is the schematic of one Embodiment of the annular | circular shaped piezoelectric element used for the vibration wave motor of this invention. For convenience of explanation, the display of the connecting electrode is omitted. It is the schematic which shows the measuring method of the length of the circumferential direction of the outer diameter side of the projection part of an annular | circular shaped diaphragm used for the vibration wave motor of this invention, and a groove part. It is the schematic which shows distribution of the center depth of the groove part of the diaphragm in one Embodiment of the vibration wave motor of this invention. It is the schematic which shows distribution of the center depth of the groove part of the diaphragm in one Embodiment of the vibration wave motor of this invention. FIG. 1 is a schematic exploded perspective view showing an embodiment of a vibration wave motor according to the present invention. It is a schematic diagram which shows one Embodiment of the drive control system of this invention. FIG. 1 is a schematic view showing an embodiment of an optical apparatus of the present invention. FIG. 1 is a schematic view showing an embodiment of an optical apparatus of the present invention. It is the schematic which shows an example of the annular diaphragm used for the vibration wave motor of this invention. It is a schematic process drawing which shows an example of the manufacturing method of the annular | circular shaped piezoelectric element used for the vibration wave motor of this invention. It is a figure which shows an example of the impedance curve of the vibrator | oscillator used for the vibration wave motor of this invention. It is the schematic which shows the installation position of the vibration damping member used for the vibration wave motor of this invention. It is the schematic which shows the installation position of the vibration damping member used for the vibration wave motor of this invention.

  Hereinafter, embodiments of a vibration wave motor, a drive control system, and an optical apparatus according to the present invention will be described.

Vibrators and vibrators that can be used for vibratory motors
The vibration wave motor of the present invention is
Mobile and
A vibrator having an annular diaphragm and an annular piezoelectric element;
A vibration damping member,
Are vibration wave motors provided in order, and
It has a plurality of grooves extending radially from the center of the annular diaphragm,
At least one of the plurality of grooves has a different depth,
It is characterized in that the pressure is unevenly applied by the vibration damping member.

The vibration wave motor of the present invention is
Mobile and
A vibrator having an annular diaphragm and an annular piezoelectric element;
A vibration damping member,
Are vibration wave motors provided in order, and
The diaphragm has radially extending groove portions at X locations on the movable body side, and when the center depths of the groove portions at the X locations are D1 to DX in order in the circumferential direction, one or more of D1 to DX are It has changed along the curve where sine waves are superimposed,
A part or all of the abdomen of the standing wave generated when the vibration wave motor is driven is strongly pressurized by the vibration damping member compared with other than the abdomen of the standing wave.

  1 (a) and 1 (b) are schematic views showing an embodiment of a vibration wave motor according to the present invention. FIG. 1 (a) is a schematic perspective view of the vibration wave motor as viewed obliquely, and FIG. 1 (b) is a schematic plan view of the vibration wave motor as viewed from the side provided with a plurality of electrodes (pattern electrodes). is there. However, in FIG. 1 (b), the display of the vibration damping member 4 and the pressure member 5 is omitted and illustrated as transparent. FIG. 2 is a schematic partial side view of the detailed configuration of an embodiment of the oscillatory wave motor according to the present invention as viewed from the side. Here, the side means a position radially away from the ring. As shown in FIG. 1A, the vibration wave motor of the present invention includes a vibrator 1, a moving body 2, a vibration damping member 4 and a pressure member 5. The vibrator 1 is formed of an annular diaphragm 101 and an annular piezoelectric element 102 provided on a first surface (piezoelectric element side) of the diaphragm.

(Annular)
In the present invention, as described at the beginning, an annular shape refers to a form in which a disk having a predetermined thickness has a concentric through hole. The outer peripheral shape of the disc and the through hole is ideally a perfect circle, but it may also be an ellipse, an oval or the like as long as it can be regarded schematically as a circle. When the circle is not a perfect circle, the radius and diameter are determined on the assumption of a true circle of the same area. A substantially annular shape such as a shape in which a part of the annular ring is missing or a shape in which a part of the annular ring protrudes is also included in the annular ring of the present invention as long as it can be regarded as a substantially annular ring. Therefore, due to manufacturing variations, a slightly deformed substantially annular shape is also included in the annular shape of the present invention as long as it can be regarded as substantially annular. The radius and diameter in the case of a substantially annular shape are determined on the assumption of a perfect circle in which the defect portion and the abnormal portion are compensated.

(Vibration damping member)
The vibration damping member 4 is provided on the surface of the piezoelectric element 102 as shown in FIG. By separately providing the vibration damping member 4 or making the thickness uneven, the abdomen of the unnecessary standing wave is locally suppressed, and the pressure is stronger than other than the abdomen of the standing wave, so the unnecessary constant is determined. The amplitude of the standing wave can be suppressed. That is, the amplitude of the unnecessary standing wave can be suppressed by pressurizing the vibration damping member unevenly. When at least one of the plurality of grooves has a different depth, the position of the abdomen of the standing wave is always constant. Therefore, it is possible to locally and continuously suppress a portion with a large amplitude, which is the abdomen of the standing wave.

  The vibration damping member 4 is made of a vibration insulating material (anti-vibration property) which hardly transmits the vibration of the vibrator to the pressure member, and for example, felt, fabric, rubber, cork, resin or the like can be used as the material. Among these, felt is a preferable material because it has high vibration insulation and is inexpensive.

(Pressure member)
The pressurizing member 5 presses the diaphragm 101 toward the movable body through the vibration damping member by pressurization, and a predetermined force is applied between the second surface (the movable body side) of the diaphragm 101 and the movable body. Members. By fixing the pressing member 5 in a pressed state, an arbitrary force can be applied between the second surface of the diaphragm 101 and the moving body.

  Furthermore, in the vibration wave motor according to the present invention, the pressure member 5 is provided separately, or the thickness is made uneven, or uneven. As a result, the amplitude of the unwanted standing wave can be suppressed by locally suppressing the non-uniform abdominal portion of the unnecessary standing wave of the vibrator via the vibration damping member 4.

  The pressure member 5 is, for example, a wave washer that generates a load by bending and bending a flat washer into an arch shape, and a spring 501 such as a disc spring as shown in FIG. It is good to make it the structure which piled up.

(Vibrator)
The vibrator 1 includes an annular diaphragm 101 and an annular piezoelectric element 102 as shown in FIG. 1A, and is in contact with the movable body 2. The piezoelectric element comprises a piezoelectric material and an electrode. When the outer periphery of the diaphragm 101 has a plurality of outer diameters depending on the measurement location, the maximum outer diameter is 2R. It is preferable that the first surface of the diaphragm 101 is a flat surface, because the transmission of the vibration accompanying the expansion and contraction of the piezoelectric element 102 is improved. The means for providing the piezoelectric element 102 on the first surface of the diaphragm 101 is not limited, but may be in close contact so as not to inhibit the transmission of vibration, or may be bonded by interposing a highly elastic adhesive layer (not shown). Is preferred. For example, an epoxy resin is suitably used as the adhesive layer.

(Mobile)
The toroidal moving body 2 is brought into pressure contact with the toroidal vibrator 1 by the pressure member 5 and is rotated by the driving force brought about by the friction generated by the traveling wave generated on the contact surface with the vibrator 1. The contact surface of the moving body 2 with the vibrator 1 is preferably planar. The moving body 2 is preferably a metal. For example, aluminum is suitably used as a material of the moving body 2.

(Configuration of piezoelectric element)
As shown in FIG. 1A, the annular piezoelectric element 102 is provided on an annular piezoelectric ceramic 1021, a common electrode 1022 provided on one surface, and the other surface. A plurality of electrodes 1023 are provided.

  In the present invention, the piezoelectric ceramic 1021 is a lump (bulk body) having a uniform and seamless composition obtained by firing a raw material powder having a metal element, and at least a part of the region is polarized. ing. The piezoelectric ceramic 1021 is a ceramic having an absolute value of the piezoelectric constant d31 of 10 pm / V at room temperature or a piezoelectric constant d33 of 30 pC / N or more.

  The piezoelectric constant of the piezoelectric ceramic can be calculated by calculation from the measurement result of the density of the ceramic and the resonant frequency and the antiresonant frequency based on the Japan Electronics Information Technology Industries Association standards (JEITA EM-4501). Hereinafter, this method is called a resonance-antiresonance method. The density can be measured, for example, by the Archimedes method. The resonant frequency and the antiresonant frequency can be measured, for example, using an impedance analyzer after providing the ceramic with a pair of electrodes.

(Content of lead in piezoelectric ceramics)
The piezoelectric ceramic 1021 is preferably a lead-free piezoelectric ceramic in which the content of lead is less than 1000 ppm.

  Most of the conventional piezoelectric ceramics have lead zirconate titanate as a main component. Therefore, for example, when the piezoelectric element is discarded and exposed to acid rain or left in a severe environment, it is pointed out that the lead component in the conventional piezoelectric ceramic may dissolve in the soil and cause harm to the ecosystem. There is. However, if the content of lead is less than 1000 ppm as in the piezoelectric ceramic 1021 of the present invention, the influence of the lead component on the environment can be suppressed to a low level. The content of lead can be evaluated, for example, by the content of lead with respect to the total weight of the piezoelectric ceramic 1021 determined by fluorescent X-ray analysis (XRF), ICP emission spectrometry.

(Perovskite metal oxide)
As a main component of the piezoelectric ceramic 1021, a metal oxide (perovskite metal oxide) having a perovskite crystal structure is preferable.

  In the present invention, the perovskite-type metal oxide is a perovskite structure which is ideally a cubic crystal structure as described in Iwanami Chemical Dictionary 5th Edition (Iwanami Shoten, published on February 20, 1998). It refers to a metal oxide having a Perovskite structure). A metal oxide having a perovskite structure is generally represented by the chemical formula of ABO3. The molar ratio of the element at the B site to the O element is expressed as 1: 3, but even if the ratio of the element amounts is slightly shifted (for example, 1.00 to 2.94 to 1.00 to 3.06), If the metal oxide has a perovskite structure as the main phase, it can be said to be a perovskite-type metal oxide. The perovskite structure of the metal oxide can be determined, for example, from structural analysis by X-ray diffraction or electron beam diffraction.

(Common electrode)
The common electrode 1022 is provided on the surface of the annular piece of piezoelectric ceramic 1021 facing the diaphragm 101, that is, the surface in contact with the diaphragm 101 or the surface in contact with the adhesive layer described above. When the common electrode 1022 is electrically connected to the non-driving phase electrode 10232 (see FIG. 1B), the driving voltage can be applied only in a specific region of the plurality of electrodes 1023, which is preferable. The common electrode can be formed, for example, by applying a metal paste such as silver and drying or baking.

(Multiple electrodes)
As shown in FIG. 1B, the electrode 1023 includes two driving phase electrodes 10231 electrically independent of each other, one or more non-driving phase electrodes 10232, and one or more sensing phase electrodes 10233.

(Detection phase electrode)
The detection phase electrode 10233 is provided for detecting the vibration state of the vibrator 1 and feeding back information on the vibration state to the outside, for example, to a drive circuit. The piezoelectric ceramic 1021 in a portion in contact with the detection phase electrode 10233 is subjected to polarization processing. Therefore, when the vibration wave motor is driven, a voltage corresponding to the magnitude of distortion of the vibrator 1 is generated at the portion of the detection phase electrode 10233 and is output to the outside as a detection signal.

(Non-driving phase electrode)
At least one or more of the non-driving phase electrodes 10232 can be used as a ground electrode when electrically connected to the common electrode 1022.

  The piezoelectric ceramic 1021 in the portion in contact with the non-driving phase electrode 10232 may or may not have remanent polarization. However, in the case where the piezoelectric ceramic 1021 in the portion in contact with the non-driving phase electrode 10232 has residual polarization, it is preferable that the non-driving phase electrode 10232 and the common electrode 1022 are electrically connected.

(Drive phase electrode)
As shown in FIG. 1B, each driving phase electrode 10231 is composed of a connecting electrode 102312 electrically connecting six polarizing electrodes 102311 and the six polarizing electrodes 102311.

  FIG. 3 is a schematic view showing the relationship between the circumferential length and the wavelength of the oscillatory wave in the annular piezoelectric element 102 used for the oscillatory wave motor of the present invention. The annular ring in the figure is substantially the same as the shape of the piezoelectric ceramic 1021. Assuming that an arbitrary position is designated on the surface of the annular ring, and the diameter of the circle passing the arbitrary position with the center being the same as the annular shape of the piezoelectric element 102 is 2 Rarb (unit mm), the circumferential length of the circle Is 2π Rarb. The circumferential length 2π Rarb is, for example, 7 λ.

  FIGS. 4A and 4B are schematic views showing the arrangement of the polarization electrode 102311 in the piezoelectric element 102 and the polarity of the piezoelectric ceramic 1021, from the side where the annular piezoelectric element 102 is provided with a plurality of electrodes. I saw it. However, in FIGS. 4A and 4B, the display of the connecting electrode 102312 is omitted for the convenience of description. The combination of the polarities shown in FIGS. 4 (a) and 4 (b) is an example and does not limit the present invention.

  The piezoelectric ceramic 1021 in a portion in contact with the driving phase electrode 10231 has residual polarization in a direction substantially perpendicular to the driving phase electrode 10231. The region having residual polarization may be part or all of the piezoelectric ceramic 1021 in the region sandwiched between the polarization electrode 102311 and the common electrode 1022. From the viewpoint of enhancing the generated force at the time of driving the vibration wave motor, it is preferable that the entire region sandwiched between the polarization electrode 102311 and the common electrode 1022 have residual polarization. In the present invention, a region having remanent polarization is referred to as a polarization part. The residual polarization refers to the polarization remaining in the piezoelectric ceramic 1021 when no voltage is applied to the piezoelectric ceramic 1021. By subjecting the piezoelectric ceramic 1021 to polarization processing, the direction of spontaneous polarization is aligned with the direction of voltage application, and residual polarization is obtained. Whether or not the piezoelectric ceramic 1021 has residual polarization can be determined by applying an electric field between the electrodes holding the piezoelectric element 102 and measuring the applied electric field E and the polarization amount P (PE hysteresis curve). It can be identified.

  Each driving phase electrode 10231 has six polarization electrodes 102311, and correspondingly, there are six portions of the piezoelectric ceramic 1021 in contact with the polarization electrodes 102311, that is, six polarization portions. As shown in FIGS. 4 (a) and 4 (b), the six polarization parts and the polarization electrodes 102311 are arranged along the circumference sandwiching the unpolarization part. The polarities of the polarized portions are alternately reversed as viewed in the order of arrangement along the circumference. In FIG. 4 (a) and 4 (b), the symbol "+" and "-" described inside the polarization electrode 102311 has shown the direction of remanent polarization, ie, polarity. In the present specification, since the symbol “+” is described on the electrode part to which a positive voltage is applied in the polarization process in the manufacturing process of the piezoelectric element 102, the piezoelectric constant d33 is measured only with the “+” electrode part. Negative values are detected. Similarly, a positive piezoelectric constant d33 is detected at the "-" electrode portion. On the other hand, the piezoelectric constant d33 at room temperature is zero or a very small value, for example, 5 pC / N or less only in the electrode part where the symbol "0" is displayed in FIG. Can only be detected. In the piezoelectric element 102 illustrated in FIGS. 4 (a) and 4 (b), the piezoelectric ceramic has a region having remnant polarization downward and a region having remnant polarization upward with respect to the paper surface. As a method of confirming that the polarity of the remanent polarization differs depending on the area, the method of judging by the positive or negative of the detected value by measuring the piezoelectric constant or the shift direction from the origin of the coercive electric field in the PE hysteresis curve is reverse. There is a way to make sure there is a certain thing.

  The size of each polarization is preferably substantially equal. In addition, each polarized portion (each polarizing electrode 102311) preferably has a difference of less than 2% in view of the projected area. As an example, assuming that the length of one arc obtained by equally dividing the circumference of the annular piezoelectric element by 7 is λ, the lengths in the circumferential direction of the two drive phase electrodes are 3 λ. Then, they are circumferentially spaced apart from each other by two spacing portions having a length of λ / 4 and 3λ / 4 in the circumferential direction, and the non-driving phase electrode and the detection phase electrode are spaced at the two spacing portions. It may be configured to be provided.

(Characteristics of electrode, material, formation method)
The polarization electrode 102311, the non-drive phase electrode 10232, the detection phase electrode 10233, and the connection electrode 102312 are formed of a layered or film conductor having a resistance value of less than 10 Ω, preferably less than 1 Ω. The resistance value of the electrode can be evaluated, for example, by measuring with a circuit meter (electric tester). The thickness of each electrode is about 5 nm to 20 μm. The material is not particularly limited as long as it is generally used for a piezoelectric element.

  As a material of an electrode, metals, such as Ti, Pt, Ta, Ir, Sr, In, Sn, Au, Al, Fe, Cr, Ni, Pd, Ag, and Cu, and these compounds can be mentioned, for example. The electrode may be made of one of these, or may be made by laminating two or more of these. Further, the electrodes disposed in the piezoelectric element may be made of different materials. Among these, as an electrode used in the present invention, an Ag paste, a baked electrode of Ag, a sputtering electrode of Au / Ti, and the like are preferable because they have small resistance values.

(Configuration of diaphragm)
The second surface of the annular diaphragm has a plurality of grooves extending radially from the center of the annular diaphragm, and at least one of the plurality of grooves has a different depth.

  Furthermore, the second surface of the annular diaphragm has radially extending grooves at X locations, and the center depths of the grooves at the X locations are D1 to DX in the circumferential direction, respectively. Preferably, DX changes along a superimposed curve of one or more sine waves.

(Number of protrusions and grooves)
As shown in FIG. 2, the second surface of the diaphragm 101 in contact with the movable body 2 has a plurality of grooves 1012 having a U-shaped cross section extending radially. The "cross-section U-shaped" referred to herein means a cross-sectional shape having bottom surfaces substantially parallel to both wall surfaces substantially perpendicular to the second surface of the diaphragm. However, the present invention is not limited to the so-called U-shape in which the bottom surface and each wall surface are round and smoothly connected. A so-called rectangular shape in which the bottom surface and the wall surfaces are connected at right angles with each other, an intermediate shape thereof, or a slight deformation from them, a shape conforming to a so-called U shape, Widely include what can be considered as

  FIG. 5 (a) is a schematic partial plan view of the diaphragm 101 as viewed from the side (the second surface) in contact with the moving body 2, and FIGS. 5 (b) -5 (d) are The example of the cross-sectional shape of the groove part of a U-shaped cross section included in invention is shown.

(protrusion)
The second surface of the diaphragm 101 has a plurality of grooves 1012 provided radially, and a projection 1011 separating the two adjacent grooves is provided. And, since a plurality of radially extending grooves 1012 are arranged in the circumferential direction, the number of protrusions 1011 formed therebetween is the same as that of the grooves. The upper surface of the protrusion 1011 corresponds to the second surface of the annular vibrator, and also serves as a reference surface when defining the depth of each groove, and can be regarded as a protrusion for the groove which is a recess. This is called a "protrusion".

(Center depth)
The central depth of the groove 1012 of the present invention is characterized in that at least one is a different depth. However, in FIG. 2, they are drawn as the same center depth. The "center depth" referred to here is the depth at the center position when each groove is viewed from the moving body side. That is, it means the depth of the groove measured from the top surface (the second surface of the vibrating body) of the protrusion at a position corresponding to the center of each groove both in the radial direction and in the circumferential direction. Usually, the bottom surface of the groove portion 1012 is generally parallel to the second surface of the diaphragm 101, and generally flat in the radial direction (the direction in which the groove extends). In addition, since the entire surface is flat in the circumferential direction (the direction in which the grooves are arranged) or the central portion is flat and the both sides (near the wall surface) are concave, the center depth is the individual groove It means the deepest part of the However, it does not necessarily mean the depth of the deepest part because it differs depending on what the bottom shape of each groove portion looks like, for example, the median of the depth (the bottom is inclined in one direction) It may also mean that the However, if the depth at the central position is a value that does not usually have a meaning as a representative value of the depth of the groove (for example, a singular point), the depth at another point near the central position The central depth is a value representative of the depth of the groove. In addition, as long as the measurement position of depth is fixed about all the groove parts, if the bottom face of each groove part has the same shape, the meaning which the center depth has becomes equivalent in all the groove parts.

  The center depths of the groove portions 1012 at the X points are respectively set to D1 to DX (unit mm) sequentially in the circumferential direction of the diaphragm. In the present invention, D1 to DX are preferably changed along a curve in which one or more sine waves are superimposed.

For example, the fourth, fifth, sixth, and eighth orders (the number of waves along the ring is 4, 5, 6) become unnecessary traveling waves for the traveling waves of seven waves along the ring targeted by the present invention. When suppressing the traveling wave of 8), it is good to change D1-DX along the curve which overlapped one or more and four or less sine waves. The general formula of the curve which superimposed the sine wave in that case becomes like following Numerical formula (1).
D = D _ave + Am ₄ x sin (4 x 2 x ω + θ ₄ ) + Am ₅ x sin (5 x 2 x ω + θ ₅ ) + Am ₆ x sin (6 x 2 x ω + θ ₆ ) + Am ₈ x sin (8 x 2 x ω + θ ₈ ) Formula (1)

  In Expression (1), ω is an angle indicating the center line position of the radially extending groove of the annular diaphragm 101. θ is an angle indicating a phase difference, and is appropriately determined so as to satisfy the conditions described later according to the embodiment. D (unit mm) indicates an ideal groove depth at the center position of an arbitrary groove of the annular diaphragm 101, and D1 to DX is D ± 0.1 mm. Further, the magnitude relationship between D1 and DX is identical to D calculated by equation (1). Dave (unit mm) is a standard depth of the groove portion 1012 which is separately set as an average value of D1 to DX.

  Am (unit mm) is a real number that represents the amplitude of each superimposed sine wave in a curve representing the change in the center depth of the groove, and the suffix indicates the order (wave number) of the unwanted traveling wave intended to be reduced ing. At least one or more of Am4, Am5, Am6 and Am8 take values other than zero. The number of sine waves with non-zero amplitude is the number of superpositions of sine waves. The upper limit of the number of superpositions of sine waves is not particularly limited as long as it is one or more. However, even if five or more sine waves are superposed, the effect of reducing the unnecessary traveling wave is not significantly improved. Efficiency may be reduced. Therefore, the number of superposition of sine waves is preferably 1 or more and 4 or less. The number of superposition of sine waves is more preferably 2 or more and 4 or less.

  6 (a) -6 (f) are schematic views showing changes in the center depth of the groove of the diaphragm in one embodiment of the vibration wave motor according to the present invention, respectively. 6 (a), 6 (c) and 6 (e) are an example showing the difference between the central depth of each groove and the standard depth Dave assuming X = 90. The horizontal axis of the plot indicates the order of 90 grooves (hereinafter referred to as groove number). Although the number 0 does not exist originally, it is used for convenience in order to indicate the depth of the 90th groove twice on the plot. The plot of the depth of each groove in FIGS. 6 (a) and 6 (c) is in each case along a curve superimposed of two sine waves. Also, the plot of the depth of each groove in FIG. 6 (e) is along a curve in which four sine waves are superimposed. FIGS. 7 (a), 7 (b), 7 (c) and 7 (d) show groove depths for suppressing the fourth, fifth, sixth and eighth traveling waves, respectively. When these sine waves are superimposed, a curve shown in FIG. 6 (e) is obtained.

  FIG. 6 (b) shows the central depth of each groove shown in FIG. 6 (a) as the standard depth Dave = 1.85 mm, and FIG. 6 (f) shows the groove shown in FIG. 6 (e). The center depth is a standard depth Dave = 1.85 mm. Each drawing is a schematic diagram showing the relationship between the height and the depth of the projection and the groove when applied to the diaphragm 101 respectively. Further, in FIG. 6D, the height and depth of the protrusions and grooves when applied to the diaphragm 101 with the center depth of each groove shown in FIG. 6C as the standard depth Dave = 1.65 mm. It is a schematic diagram which plots and shows the relationship of. In these examples, the heights of the protrusions starting from the first surface of the diaphragm are equal. The horizontal axis of the plot indicates the positions (stretching directions) of the 90 grooves at an angle viewed from the center of the torus. The values on the horizontal axis are relative ones, but in FIG. 6 (b), the end of the groove No. 89 in FIG. 6 (a) is the starting point. Also, in FIG. 6 (d), the end of groove 89 in FIG. 6 (c) is the starting point, and in FIG. 6 (f), the end of groove 89 in FIG. 6 (e) is the starting point And

  By setting the groove depth as shown in FIG. 6 (a) -6 (f), the unnecessary traveling wave (quartic, fifth, sixth, eighth) selected for the seventh-order traveling wave is obtained. Occurrence is greatly suppressed. For example, focusing only on the fourth-order unnecessary traveling wave, as shown in the second term of the equation (1), the center depth of the groove is 8 local maximums (deep portions) and 8 local It comes to have minimum parts (shallow parts) at equal intervals (angle of π / 4). Since the positions of the antinodes of the standing waves generated in the two drive phase electrode parts are also shifted at an angle of π / 4, one of the standing waves vibrates at a point where the elastic modulus is low, so the resonant frequency is Shift to the low frequency side. The other standing wave vibrates at a high elastic modulus, so the resonance frequency shifts to the high frequency side. As the resonant frequencies of the standing waves mutually separate, as a result, the fourth-order traveling wave (unwanted traveling wave) is not generated. The suppression mechanism is the same for the unwanted traveling waves of other orders.

  Make sure that the center depth of the X groove 1012 in the diaphragm 101 of the vibration wave motor is at least one different depth and changes along a curve obtained by superposing one or more sine waves. The following method can be illustrated as a method. First, the coordinates and depth of the central portion of each groove with respect to the circumferential length on the outer diameter side of the diaphragm are measured. The coordinate of the groove is taken on the horizontal axis, and the measured depth is taken on the vertical axis, and the plots are complemented to assume a curve in which the groove depth exists at all the coordinates. By Fourier transforming this curve, the existence and number of sine waves can be known.

(Relationship between sensing phase electrode and groove center depth)
Of the grooves 1012 at the X locations, the central depth of the groove closest to the detection phase electrode 10233 is Dsen. Here, "sen" is a natural number and is 1 or more and X or less. The closest groove is determined with the center of the detection phase electrode 10233 as a reference point. Let Dsen-1 and Dsen + 1 be the center depths of two groove portions adjacent to the closest groove portion. At this time, it is preferable that | Dsen + 1-Dsen-1 | / Dsen is 5% or less. It is more preferable that | Dsen + 1−Dsen−1 | / Dsen ≦ 2%. By setting the relationship between the central depths of the three groove portions within the above range, the central depths of the adjacent groove portions centering on the detection phase electrode 10233 become close. As a result, the amplitude of the vibrator 1 in the vicinity of the detection phase electrode 10233 at the time of driving of the vibration wave motor is approximately the same whether it is clockwise or counterclockwise driving, and the vibration wave by the drive circuit Motor drive control becomes easy.

(Material of diaphragm)
The diaphragm 101 is preferably an elastic body for the purpose of forming a traveling wave of bending vibration integrally with the piezoelectric element 102 and transmitting the vibration to the moving body 2. Further, the diaphragm 101 is preferably made of metal in terms of the property as an elastic body and the processability. Examples of metals that can be used for the diaphragm 101 include aluminum, brass, Fe-Ni 36% alloy, and stainless steel. Among them, it is stainless steel that can obtain a high rotation speed in combination with the piezoelectric ceramic 1021 having a Young's modulus of 100 GPa or more and 135 GPa or less at room temperature used in the present invention. The stainless steel as used herein refers to an alloy containing 50% by mass or more of steel and 10.5% by mass or more of chromium. Among stainless steels, martensitic stainless steel is preferable, and SUS420J2 is most preferable as a material of the diaphragm 101.

(Shape of vibration damping member)
8 (a), 8 (b) and 8 (c) are perspective views schematically showing the state of the vibration wave motor at a certain time during driving. This is an embodiment in which the shapes of the vibration damping member 4 and the pressure member 5 are different, and the effect of the present invention can be obtained in any form. 8 (a), 8 (b) and 8 (c) are views of the vibration wave motor seen from an oblique direction, and in fact the vibrator, the moving body and the vibration damping member are pressurized by the pressure member. Although they are in contact, they are illustrated separately in the central axis direction of the annular ring. However, illustration of the electrodes of the piezoelectric element is omitted.

  In order to suppress the 4th, 5th, 6th, and 8th traveling waves other than the 7th traveling wave, the groove depth has 4th, 5th, 6th, and 8th sine waves superimposed on the diaphragm. It is changing along the combined curve.

  The vibrator 1 of FIG. 8 represents a deformed state when the amplitude of the unnecessary sixth order standing wave generated when the oscillatory wave motor is driven becomes maximum, and the antinode of the sixth order unnecessary standing wave The vibration damping member 4 is provided so as to suppress the position (abdomen) of. However, the amount of deformation of the vibrator 1 is illustrated with a large deformation ratio. As shown in FIG. 8, by providing the vibration damping member 4 at a position corresponding to a part or all of the abdomen of the standing wave, the pressurization by the pressing member 5 becomes uneven and the vibration damping member 4 is positioned. It grows locally.

  In order to confirm the position of the abdomen of a standing wave of any order generated when the oscillatory wave motor is driven, an input signal of a small voltage (for example, a small voltage to the drive phase electrode of the oscillator) is firstly Input an AC voltage of 1V to 10V. Then, it can be confirmed by measuring the vibration amplitudes of all the grooves or projections of the vibrator while changing the frequency of the input signal using, for example, a laser Doppler vibrometer. The point at which the vibration amplitude is minimized is a node, the position is called a node, the point at which the vibration amplitude is maximized is an antinode, and the position is called an abdomen.

  When the unnecessary standing waves of the same order appear at different places at a plurality of frequencies, the vibration damping member 4 may be provided to suppress the abdomen of each standing wave. The vibration damping member 4 may be provided to select the unnecessary standing wave having the larger vibration amplitude and suppress its abdomen.

  Where to provide the vibration damping member may be determined in another way.

  The vibration wave motor according to the present invention is a vibration wave motor including a vibrator, a moving body, a vibration damping member, and a pressure member, wherein the vibrator is an annular diaphragm, and the first of the diaphragms. It comprises an annular piezoelectric element provided on the surface. The diaphragm is in contact with the movable body at a second surface opposite to the first surface. The piezoelectric element may be a ring-shaped piece of piezoelectric ceramic, a common electrode provided on the surface of the piezoelectric ceramic facing the diaphragm, and a surface on which the common electrode of the piezoelectric ceramic is provided. And a plurality of electrodes provided on the surface of the

  The second surface of the annular diaphragm has radially extending grooves at X points, and D1 to DX is 1 when the center depth of the grooves at the X points is sequentially D1 to DX in the circumferential direction. It is preferable to change along a curve in which three or more sine waves are superimposed. And it is preferable that the said pressurization is locally large in part or all of a sine wave abdominal part.

  FIG. 7C shows the groove depth for suppressing the sixth-order traveling wave, and the groove depth changes so as to follow the sine wave curve represented by the equation (1).

  The vibration amplitude of the sixth-order unnecessary standing wave with the groove depth becoming maximum at the maximum tends to be large. Therefore, by providing the vibration damping member on the abdomen of the sixth unnecessary unwanted standing wave, that is, the abdominal portion of the sine wave in FIG. 7C, the abdominal of the unwanted standing wave can be suppressed and the vibration amplitude can be reduced. . As a result, the generation of abnormal noise and the reduction in output can be suppressed.

  As shown in FIG. 8B, in one piece of the vibration damping member, the thickness of the vibration damping member is increased in part or all of the abdomen of the standing wave generated when the vibration wave motor is driven, The configuration may be such that the pressure is locally increased.

  In the vibration wave motor according to the present invention, preferably, the contact portion between the vibration damping member and the piezoelectric element is separated into a plurality of places. As shown in FIG. 8A, the contact portion between the vibration damping member and the piezoelectric element can be pressurized more locally than in the configuration of FIG. 8B by being separated into a plurality of places. Therefore, unnecessary standing waves can be suppressed more effectively.

  The vibration damping members 4 have an annular shape in the example of FIGS. 8B and 8C, but when separated as shown in FIG. 8A, each vibration damping member 4 has a fan shape.

  In the above configuration example, the pressure is locally increased in the entire abdomen of the standing wave generated when the vibration wave motor is driven. In addition, the same effect can be obtained even if the pressure is locally increased at a part of the abdomen of the standing wave generated when the vibration wave motor is driven. However, in order to suppress the unnecessary standing wave more effectively, the pressurization is locally increased in the entire abdomen of the standing wave generated when the vibration wave motor is driven. Is good.

(Pressure is local)
Here, whether pressure is locally increased at a place as expected is determined by, for example, inserting a pressure-sensitive paper or a film-like pressure sensor between the vibrator and the vibration damping member and pressing the pressure by the pressure member. You can check it by yourself.

(The circumferential length of the vibration damping member)
When the vibration damping members are provided separately, the circumferential length of each of the vibration damping members is preferably as short as possible. In order to suppress unnecessary standing waves more effectively, assuming that the wavelength of the Nth standing wave generated when the vibration wave motor is driven is PN, the abdomen of the Nth standing wave is centered Preferably shorter than PN / 4. As a result, the pressure increases locally locally, so that unnecessary standing waves are further suppressed. Further, from the viewpoint of processability, the shortest part of the circumferential length of the vibration damping member is preferably 1 mm or more.

(Thickness and width of vibration damping member)
The thickness of the vibration damping member is preferably 0.3 mm or more and 2 mm or less.

  When the pressing member vibrates, noise is generated. Therefore, in order to prevent the vibration of the vibrator from being transmitted to the pressing member through the vibration damping member, the thickness is preferably 0.3 mm or more. Also, when the vibration of the vibrator is transmitted to the moving body, if the thickness of the vibration damping member is thick, the traveling wave of the desired order (for example, the seventh order) for driving the vibration wave motor is absorbed too much and the moving body is It becomes difficult to transmit the force as a reaction force. The preferred thickness of the vibration damping member is 2 mm or less.

  The inner diameter of the vibration damping member is preferably larger than the inner diameter of the piezoelectric element, and the outer diameter of the vibration damping member is preferably equal to or less than the outer diameter of the piezoelectric element. If the outer diameter of the vibration damping member is larger than the piezoelectric element, the outer edge portion of the vibration damping member may inhibit the vibration of the piezoelectric element.

  Although the inner diameter and the outer diameter of the vibration damping member have been described above, the inner diameter is preferably larger than the inner diameter of the piezoelectric element and the outer diameter is preferably smaller than the outer diameter of the piezoelectric element.

(Shape of pressure member)
The vibration wave motor of the present invention may be configured such that the pressing member has a convex portion at a position where the abdomen of the standing wave is pressed.

  In FIG. 8C, a convex portion 5021 is provided on an annular flat plate which constitutes a pressure member. The convex portion 5021 can be provided by press processing or the like, and the position thereof is the entire abdomen of the sixth unnecessary unwanted standing wave of the vibrator. Part or all of the abdomen of the standing wave (unnecessary standing wave) generated when the vibration wave motor is driven by having the convex portion 5021 at a location where the pressing member pressurizes the abdomen of the standing wave The pressure locally increases at. By suppressing the abdomen of the unwanted standing wave, the vibration amplitude of the unwanted standing wave can be reduced. As a result, it is possible to suppress the generation of abnormal noise of the unnecessary standing wave and the output decrease.

  Here, in FIG. 8C, one pressing member is provided. However, as in the vibration damping member of FIG. 8A, when a separated pressing member is used to drive the vibration wave motor The pressure member may be provided in part or all of the abdomen of the standing wave generated in the. With such a configuration, the pressure may be locally increased. The convex portion may have a structure that can be locally pressurized, and may have a triangular convex shape or a spherical convex shape.

(Circumferential length, thickness and width of convex part of pressure member)
In the case where the pressing member is provided with the convex portion 5021, the circumferential length of each pressing member is preferably as short as possible. In order to suppress unnecessary standing waves more effectively, assuming that the wavelength of the Nth standing wave generated when the vibration wave motor is driven is PN, the abdomen of the Nth standing wave is centered Preferably shorter than PN / 4. As a result, the pressure increases locally locally, so that unnecessary standing waves are further suppressed. Further, from the viewpoint of processability, the shortest part of the circumferential length of the convex portion 5021 of the pressing member is preferably 1 mm or more.

  The thickness of the pressure member is preferably 1 mm or more and 10 mm or less. When the thickness of the pressing member is 1 mm or more, for example, processing by press processing or the like becomes easy. If the thickness of the pressing member exceeds 10 mm, the vibration wave motor becomes large, which makes it difficult to apply to, for example, a small optical apparatus.

  Preferably, the inner diameter of the pressure member is substantially the same as the inner diameter of the vibration damping member. By making the inner diameter of the pressing member substantially the same as the inner diameter of the vibration damping member, alignment when providing the pressing member adjacent to the vibration damping member is facilitated.

  8 (a) to 8 (c), the method of suppressing the sixth-order unnecessary standing wave has been described as an example of the embodiment of the present invention. The method of suppressing the unnecessary standing waves of the other orders may be implemented by the same method, so that the pressure applied by the pressing member locally increases in part or all of the unnecessary standing waves of the orders to be suppressed. Just do it.

  Furthermore, in the present description, a vibration wave motor using a seventh order bending vibration wave has been taken as an example, but the present invention is also applicable to the case of using bending vibration waves of other orders. For example, in a vibration wave motor using a sixth bending vibration wave, unnecessary standing waves other than the sixth order may be suppressed. The pressure applied by the pressing member may be locally increased in part or all of the unnecessary standing waves to be suppressed. Similarly, the present invention can be applied to a vibration wave motor that utilizes arbitrary bending vibration waves such as eighth order and eleventh order.

(Maintain the positional relationship during driving)
With the above configuration, unnecessary standing waves can be suppressed, but if the circumferential arrangement of the three members of the annular diaphragm, the vibration damping member, and the pressing member changes during driving, the unnecessary standing waves The effect of suppressing Therefore, in the vibration wave motor according to the present invention, it is preferable that the circumferential arrangement of the annular diaphragm, the vibration damping member, and the three members of the pressure member be fixed to each other. In order to fix them, they may be adhered to each other using an adhesive, or non-slip members may be sandwiched between the members. Further, it may be fixed to other parts with an adhesive or the like.

(Piezoelectric ceramics are barium titanate based materials)
The composition of the piezoelectric ceramic 1021 is not particularly limited as long as the content of lead is less than 1000 ppm (ie, lead-free). For example, piezoelectric ceramics having a composition such as barium titanate, barium calcium titanate, barium calcium titanate zirconate, bismuth sodium titanate, potassium sodium niobate sodium barium niobate titanate, bismuth ferrate, or the like Piezoelectric ceramics which are main components can be used for the vibration wave motor and vibrator 1 of the present invention.

  The piezoelectric ceramic constituting the vibration wave motor of the present invention is preferably made of a barium titanate material.

  The barium titanate material refers to a material whose main phase is a perovskite structure and contains titanium and barium. By using a barium titanate material, it is possible to obtain a high piezoelectric constant necessary for driving the vibration wave motor.

More preferred barium titanate based material is represented by the general formula (1)
(Ba1-xCax) α (Ti1-yZry) O3 (1)
However,
0.986 ≦ α ≦ 1.100,
0.02 ≦ x ≦ 0.30,
0.020 ≦ y ≦ 0.095
Wherein the content of the metal component other than the main component contained in the piezoelectric ceramic is not more than 1.25 parts by weight in terms of metal based on 100 parts by weight of the metal oxide. .

  In particular, Mn is contained in the metal oxide, and the content of the Mn is preferably 0.02 parts by weight or more and 0.40 parts by weight or less in terms of metal based on 100 parts by weight of the metal oxide. .

  The metal oxide represented by the general formula (1) means that the metal elements located at the A site are Ba and Ca, and the metal elements located at the B site are Ti and Zr. However, some Ba and Ca may be located at the B site. Similarly, some Ti and Zr may be located at the A site.

  The molar ratio of the element at the B site to the O element in the general formula (1) is 1: 3, but even if the molar ratio is slightly deviated, it is sufficient if the perovskite structure is the main phase.

  The perovskite structure of the metal oxide can be determined, for example, from structural analysis by X-ray diffraction or electron beam diffraction.

  X which shows the molar ratio of Ca in A site in General formula (1) is the range of 0.02 <= x <= 0.30. When a part of Ba in the perovskite type barium titanate is replaced with Ca in the above range, the phase transition temperature between orthorhombic and tetragonal shifts to the low temperature side. Stable piezoelectric vibration can be obtained. However, if x is larger than 0.30, the piezoelectric constant of the piezoelectric ceramic is not sufficient, and the rotational speed of the vibration wave motor may be insufficient. On the other hand, if x is smaller than 0.02, dielectric loss (tan δ) may increase. When the dielectric loss increases, the heat generated when the motor is driven by applying a voltage to the piezoelectric element 102 increases, and the motor driving efficiency may be reduced.

  In General formula (1), y which shows the molar ratio of Zr in B site is the range of 0.020 <= y <= 0.095. If y is smaller than 0.020, the piezoelectric constant of the piezoelectric ceramic is not sufficient, and the rotational speed of the vibration wave motor may be insufficient. On the other hand, if y is larger than 0.095, the depolarization temperature, which is the piezoelectric ceiling temperature, may decrease as the depolarization temperature (Td) becomes lower than 80 ° C., and the piezoelectric characteristics of the piezoelectric ceramic 1021 may disappear at high temperatures. is there.

  In the present specification, the depolarization temperature (also referred to as Td) means that after sufficient time after polarization treatment, the piezoelectric constant is increased from room temperature to a certain temperature Td (° C.) and then lowered again to room temperature. Refers to a temperature that is decreasing compared to the piezoelectric constant before raising. In the present specification, a temperature which is less than 90% of the piezoelectric constant before the temperature is raised is called depolarization temperature Td.

  Further, in the general formula (1), α, which indicates the ratio of the molar amount of Ba to Ca at the A site and the molar amount of Ti to Zr at the B site, is in the range of 0.986 ≦ α ≦ 1.100. preferable. If α is smaller than 0.986, abnormal grain growth is likely to occur in the crystal grains constituting the piezoelectric ceramic 1021, and the mechanical strength of the piezoelectric ceramic 1021 is reduced. On the other hand, if α is larger than 1.100, the temperature required for grain growth of the piezoelectric ceramic 1021 becomes too high, and sintering can not be performed in a general firing furnace. Here, “incapable of sintering” means that the density does not have a sufficient value, or that a large number of pores and defects exist in the piezoelectric ceramic.

  The means for measuring the composition of the piezoelectric ceramic 1021 is not particularly limited. Means include X-ray fluorescence analysis, ICP emission spectroscopy, atomic absorption analysis and the like. The weight ratio and the composition ratio of each element contained in the piezoelectric ceramic 1021 can be calculated by using any measurement means.

  The piezoelectric ceramic 1021 contains a perovskite-type metal oxide represented by the general formula (1) as a main component, and the metal oxide contains Mn. The content of Mn is preferably 0.02 parts by weight or more and 0.40 parts by weight or less in terms of metal with respect to 100 parts by weight of the metal oxide.

  When the content of Mn in the above range is included, the insulating property and the mechanical quality factor Qm are improved. Here, the mechanical quality factor Qm is a factor representing an elastic loss due to vibration when the piezoelectric element is evaluated as a vibrator, and the magnitude of the mechanical quality factor is observed as the sharpness of the resonance curve in the impedance measurement. Ru. That is, it is a constant representing the sharpness of resonance of the piezoelectric element. When the mechanical quality factor Qm is large, the strain amount of the piezoelectric element becomes larger near the resonance frequency, and the piezoelectric element can be effectively vibrated.

  The improvement of the insulating property and the mechanical quality factor is considered to be derived from the fact that a defect dipole is introduced by Mn having a valence different from Ti and Zr to generate an internal electric field. When an internal electric field is present, the reliability of the piezoelectric element 102 can be secured when a voltage is applied to the piezoelectric element 102 to drive it.

  Here, metal conversion indicating the content of Mn means each of Ba, Ca, Ti, Zr, and Mn measured from the piezoelectric ceramic 1021 by fluorescent X-ray analysis (XRF), ICP emission spectral analysis, atomic absorption analysis or the like. It is calculated from the metal content. That is, the element which comprises the metal oxide represented by General formula (1) is converted into an oxide from those content, and the value calculated | required by the ratio with respect to the weight of Mn with respect to when the total weight is 100 is represented.

  If the content of Mn is less than 0.02 parts by weight, the effect of the polarization process necessary for driving the piezoelectric element 102 may not be sufficient. On the other hand, when the content of Mn is larger than 0.40 parts by weight, piezoelectric properties may not be sufficient, or crystals of hexagonal crystal structure not contributing to the piezoelectric properties may be developed.

  Mn is not limited to metal Mn, as long as it is contained in the piezoelectric material as an Mn component, and the form of the content is not limited. For example, it may be in solid solution at the B site or may be contained in grain boundaries. Alternatively, the Mn component may be contained in the piezoelectric ceramic 1021 in the form of metal, ion, oxide, metal salt, complex or the like. A more preferable form of inclusion is to form a solid solution in the B site from the viewpoint of insulating property and sinterability. Assuming that the ratio of the molar amount of Ba and Ca at the A site to the molar amount of Ti, Zr and Mn at the B site is A2 / B2 when dissolved in the B site, the preferable range of A2 / B2 is 0.993 ≦ It is A2 / B2 <= 0.998.

  The piezoelectric ceramic 1021 may contain 0.042 to 0.850 parts by weight of Bi in terms of metal per 100 parts by weight of the metal oxide represented by the general formula (1). The content of Bi relative to the metal oxide can be measured, for example, by ICP emission spectroscopy. Bi may be present at the grain boundaries of the ceramic piezoelectric material, or may be in solid solution in the (Ba, Ca) (Ti, Zr) O 3 perovskite structure. The presence of Bi at grain boundaries reduces interparticle friction and increases the mechanical quality factor. On the other hand, when Bi is incorporated into a solid solution forming a perovskite structure, the temperature transition of the piezoelectric constant is reduced because the phase transition temperature is lowered, and the mechanical quality factor is further improved. It is preferable that the position when the Bi is incorporated into the solid solution be the A site, because the charge balance with the Mn is improved.

  The piezoelectric ceramic 1021 may contain the element contained in the general formula (1) and components other than Mn and Bi (hereinafter, subcomponents) in the range in which the characteristics do not change. The total amount of the auxiliary components is preferably less than 1.2 parts by weight with respect to 100 parts by weight of the metal oxide represented by the general formula (1). If the amount of the accessory component exceeds 1.2 parts by weight, the piezoelectric properties and the insulating properties of the piezoelectric ceramic 1021 may be degraded. The content of metal elements other than Ba, Ca, Ti, Zr, and Mn among the auxiliary components is 1.0 part by weight or less in terms of oxide or 0.1% in terms of metal with respect to 100 parts by weight of the piezoelectric ceramic. It is preferably 9 parts by weight or less. In the present invention, metal elements also include metalloid elements such as Si, Ge and Sb. When the content of metal elements other than Ba, Ca, Ti, Zr, and Mn exceeds 1.0 part by weight in oxide conversion or 0.9 part by weight in metal conversion with respect to 100 parts by weight of piezoelectric ceramic, piezoelectric There is a possibility that the piezoelectric properties and the insulation properties of the ceramic 1021 may be significantly reduced.

  Here, Sr and Mg may be contained in the piezoelectric material of the present invention to such an extent that they are contained as unavoidable components in the commercially available materials of Ba and Ca. Similarly, Nb which is contained as an unavoidable component in the commercially available raw material of Ti and Hf which is contained as an unavoidable component in the commercially available raw material of Zr may be contained in the piezoelectric ceramic 1021 of the present invention.

  The means for measuring the parts by weight of the accessory component is not particularly limited. Means include fluorescent X-ray analysis (XRF), ICP emission spectral analysis, atomic absorption analysis and the like.

(Drive control system)
Next, the drive control system of the present invention will be described. FIG. 9 is a schematic view showing an embodiment of a drive control system of the present invention. The drive control system at least includes the vibration wave motor of the present invention and a drive circuit electrically connected to the vibration wave motor. The drive circuit incorporates a signal generation mechanism that generates a seventh-order bending vibration wave in the vibration wave motor of the present invention and emits an electrical signal for rotational driving.

  The drive circuit simultaneously applies an alternating voltage having the same frequency and a temporal phase difference of π / 2 to each drive phase electrode 10231 (A phase and B phase) of the vibration wave motor. As a result, standing waves generated in the A phase and the B phase are combined, and a seventh-order bending vibration wave (wavelength λ) traveling in the circumferential direction is generated on the second surface of the diaphragm 101.

  At this time, since each point on the protrusion 1011 of the X portion of the diaphragm 101 performs an elliptical motion, the movable body 2 receives a frictional force in the circumferential direction from the diaphragm 101 and rotates. When the seventh order bending vibration wave is generated, the detection phase electrode 10233 generates a detection signal according to the amplitude of the vibration of the piezoelectric ceramic 1021 in a portion in contact with the electrode, and outputs the signal to the drive circuit through the wiring. The drive circuit compares the phase of the detection signal with the phase of the drive signal input to the drive phase electrode 10231 to grasp the deviation from the resonance state. By determining again the frequency of the drive signal input to the drive phase electrode 10231 from this information, feedback control of the oscillatory wave motor becomes possible.

(Optical equipment)
Next, the optical apparatus of the present invention will be described. The optical apparatus of the present invention is characterized by having a drive control system using the vibration wave motor of the present invention and an optical member supported by the vibration wave motor.

  10 (a) and 10 (b) are main cross-sectional views of the interchangeable lens barrel of a single-lens reflex camera which is an example of the preferred embodiment of the optical apparatus according to the present invention. FIG. 11 is an exploded perspective view of the interchangeable lens barrel of the single-lens reflex camera which is an example of the preferred embodiment of the optical apparatus according to the present invention. A fixed barrel 712, a rectilinear guide barrel 713, and a front lens group barrel 714 for holding the front lens group 701 are fixed to the detachable mount 711 for the camera. These are fixing members of the interchangeable lens barrel.

  In the rectilinear guide cylinder 713, a rectilinear guide groove 713a in the optical axis direction for the focus lens 702 is formed. Cam rollers 717a and 717b protruding radially outward are fixed by a shaft screw 718 to the rear lens group barrel 716 holding the focus lens 702, and the cam roller 717a is fitted in the rectilinear guide groove 713a.

  A cam ring 715 is rotatably fitted on the inner circumference of the rectilinear guide cylinder 713. The relative movement in the optical axis direction of the rectilinear guide cylinder 713 and the cam ring 715 is restricted by the roller 719 fixed to the cam ring 715 being fitted into the circumferential groove 713 b of the rectilinear guide cylinder 713. A cam groove 715a for the focus lens 702 is formed in the cam ring 715, and the above-mentioned cam roller 717b is simultaneously fitted in the cam groove 715a.

  A rotation transmission ring 720 which is held by the ball race 727 so as to be able to rotate at a fixed position relative to the fixed cylinder 712 is disposed on the outer peripheral side of the fixed cylinder 712. A roller 722 is rotatably held by a shaft 720f radially extending from the rotation transmission ring 720 in the rotation transmission ring 720, and the large diameter portion 722a of the roller 722 contacts the mount side end face 724b of the manual focus ring 724 doing. The small diameter portion 722 b of the roller 722 is in contact with the bonding member 729. Six rollers 722 are arranged at equal intervals on the outer periphery of the rotation transmission ring 720, and the respective rollers are configured in the above-described relationship.

  A low friction sheet (washer member) 733 is disposed in the inner diameter portion of the manual focus ring 724, and the low friction sheet is sandwiched between the mount side end face 712a of the fixed cylinder 712 and the front end face 724a of the manual focus ring 724 There is. Further, the outer diameter surface of the low friction sheet 733 is ring-shaped and is fitted with the inner diameter 724c of the manual focus ring 724. Furthermore, the inner diameter 724c of the manual focus ring 724 is the diameter with the outer diameter portion 712b of the fixed cylinder 712 It is fitting. The low friction sheet 733 serves to reduce the friction in the rotary ring mechanism in which the manual focus ring 724 rotates relative to the fixed barrel 712 about the optical axis.

  The large-diameter portion 722a of the roller 722 and the mount-side end surface 724b of the manual focus ring are in contact with each other in a state where a pressing force is applied by the force that the wave washer 726 presses the vibration wave motor 725 to the front. . Similarly, due to the force of the wave washer 726 pressing the vibration wave motor 725 to the front of the lens, the small diameter portion 722b of the roller 722 and the bonding member 729 are also in contact with each other in a state where an appropriate pressure is applied. The wave washer 726 is restricted in movement in the mounting direction by the washer 732 which is bayonet-coupled to the fixed cylinder 712, and the spring force (biasing force) generated by the wave washer 726 is the vibration wave motor 725 and further Then, the manual focus ring 724 also acts as a pressing force on the mount side end surface 712 a of the fixed barrel 712. That is, the manual focus ring 724 is incorporated in a state of being pressed against the mount side end surface 712 a of the fixed cylinder 712 via the low friction sheet 733.

  Therefore, when the vibration wave motor 725 is rotationally driven with respect to the fixed cylinder 712 by the drive circuit including a signal generation mechanism (not shown), the bonding member 729 is in frictional contact with the small diameter portion 722b of the roller 722, The roller 722 rotates around the center of the shaft 720f. When the roller 722 rotates around the shaft 720f, as a result, the rotation transmission ring 720 rotates around the optical axis (autofocus operation).

  Further, when a rotational force around the optical axis is applied to the manual focus ring 724 from a manual operation input unit (not shown), the following operation is performed. That is, since the mount side end surface 724b of the manual focus ring 724 is in pressure contact with the large diameter portion 722a of the roller 722, the roller 722 rotates around the shaft 720f by the frictional force. When the large-diameter portion 722a of the roller 722 rotates around the axis 720f, the rotation transmission ring 720 rotates around the optical axis. At this time, the vibration wave motor 725 does not rotate due to the frictional holding force of the moving body 725c and the vibrator 725b (manual focus operation).

  Two focus keys 728 are attached to the rotation transmission ring 720 so as to face each other, and the focus key 728 is engaged with a notch 715 b provided at the tip of the cam ring 715. Therefore, when the auto focus operation or the manual focus operation is performed and the rotation transmission ring 720 is rotated about the optical axis, the rotational force is transmitted to the cam ring 715 through the focus key 728. When the cam ring is rotated around the optical axis, the rear lens group barrel 716 is rotationally restricted by the cam roller 717a and the rectilinear guide groove 713a, and is advanced and retracted along the cam groove 715a of the cam ring 715 by the cam roller 717b. Thereby, the focus lens 702 is driven to perform the focus operation. That is, the position of the focus lens 702 which is an optical member changes due to the mechanical connection with the vibration wave motor 725.

  Although the interchangeable lens barrel of a single-lens reflex camera has been described above as the optical apparatus of the present invention, the present invention is not limited to a variety of cameras such as compact cameras and electronic still cameras, provided with vibration wave motors. Can be applied to various optical devices.

(Electronics)
An electronic device provided with the above-described vibration wave motor can also be provided, and can be used for various applications.

  Next, the vibration wave motor, the drive control system and the optical apparatus of the present invention will be specifically described by way of examples, but the present invention is not limited by the following examples.

(Example of manufacturing an annular piece of piezoelectric ceramic)
An annular piece of piezoelectric ceramic having a lead content of less than 1000 ppm was produced as a barium titanate based material as follows.

In the general formula (1), it corresponds to a composition of x = 0.14, y = 0.06, α = 1.00 (Ba 0.86 Ca 0.14) 1.00 (Ti 0.94 Zr 0.06) O 3
The corresponding raw powders were weighed as follows, with the intention of adding Mn and Bi to the

By using barium titanate, calcium titanate and calcium zirconate having a perovskite type structure and having an average particle diameter of 300 nm or less as the raw material powder, Ba, Ca, Ti, and Zr can be (Ba0.86Ca0.14) 1.00 (Ti0.94Zr0.06) O3
It weighed so that it might become the composition of. Barium carbonate and titanium oxide were used to adjust x indicating the molar ratio of A site to B site. Said composition (Ba0.86Ca0.14) 1.00 (Ti0.94Zr0.06) O3
Trimanganese tetraoxide was added such that the content of Mn was 0.14 parts by weight in terms of metal based on 100 parts by weight of the above. Similarly, bismuth oxide was added such that the content of Bi was 0.18 parts by weight in terms of metal.

  These weighed powders were mixed by dry mixing for 24 hours using a ball mill to obtain mixed powders. In order to granulate the obtained mixed powder, a PVA binder in an amount of 3 parts by weight with respect to the mixed powder was attached to the surface of the mixed powder using a spray dryer apparatus to obtain granulated powder.

  Next, the obtained granulated powder was filled in a mold, and a disc-shaped compact was produced by applying a molding pressure of 200 MPa using a press molding machine. The size of the mold used for the disc-like molding had a margin of 2 mm, 2 mm, and 0.5 mm with respect to the outer diameter, the inner diameter, and the thickness of the target disk-like piezoelectric ceramic.

  The resulting compact was placed in an electric furnace, held at a maximum temperature of 1340 ° C. for 5 hours, and sintered in air for a total of 24 hours. Next, the sintered body is ground into an annular shape having a desired outer diameter, inner diameter, and thickness, respectively, and an annular piezoelectric ceramic with an outer diameter of 76.9 mm, an inner diameter of 67.2 mm, and a thickness of 0.5 mm. I got

The composition of the piezoelectric ceramic was evaluated by ICP emission spectroscopy. As a result, the lead content of each of the piezoelectric ceramics produced by the above method was less than 1 ppm. In addition, when the results of ICP emission spectrometry and X-ray diffraction measurement are combined, the composition of the piezoelectric ceramic is (Ba0.86Ca0.14) 1.00 (Ti0.94Zr0.06) O3.
It was found that the composition was composed mainly of a perovskite-type metal oxide that can be represented by the following composition, and 0.14 parts by weight of Mn and 0.18 parts by weight of Bi with respect to 100 parts by weight of the main components .

(Production example of diaphragm)
FIGS. 12 (a) and 12 (b) are schematic views showing an example of an annular diaphragm used for the vibration wave motor and vibrator of the present invention.

  In order to produce a diaphragm used in the present invention, an annular metal plate 101a as shown in FIG. 12 (a) was prepared. The metal plate 101a is formed of magnetic stainless steel SUS420J2 of JIS standard. SUS420J2 is a martensitic stainless steel and is an alloy containing 70% by mass or more of steel and 12 to 14% by mass of chromium.

  The outer diameter, the inner diameter and the thickness of the metal plate 101a were a metal plate 101a having an outer diameter 2R of 77.0 mm, an inner diameter of 67.1 mm and a thickness of 5.0 mm.

  Next, groove portions 1012 at 90 places (X = 90) were radially cut and formed (groove cutting) radially on one surface (second surface) of the annular metal plate 101a. The wall surface of each groove portion 1012 was vertical when viewed from the first surface of the diaphragm 101 which is not grooved. The groove bottom portion of each groove portion 1012 has a deepest center as shown in FIG. 5C. The diaphragm 101 used in the vibrator 1 of the present invention is obtained by subjecting the metal plate 101a after the grooving to barrel processing, lap polishing, and electroless nickel plating processing.

  The groove portion 1012 of the diaphragm 101 is formed in a rectangular shape of 1.0 mm in width when viewed from the second surface side, so the protrusion 1011 has a fan shape in which the width becomes wider on the outer diameter side of the annular ring.

  The central depths D1 to D90 of the 90 groove portions 1012 of the diaphragm 101 were made to be the depths shown in FIG. That is, D1 to D90 change along a curve in which four sine waves are superimposed.

  Also, the depth variation of D1 to D45 and the depth variation of D46 to D90 are as shown in Table 1. Such a configuration can suppress unnecessary traveling waves other than the seventh order.

(Example of manufacturing a vibrator)
FIGS. 13 (a) to 13 (d) are schematic process drawings showing an example of a method of manufacturing a vibrator used in the vibration wave motor of the present invention.

  A vibrator was manufactured by combining the piezoelectric ceramic shown in the above-mentioned production example and the diaphragm of the present invention.

  First, a common electrode 1022 is formed on one surface of the annular piezoelectric ceramic 1021 shown in FIG. 13A by screen printing of silver paste, as shown in FIG. 13C. As shown in FIG. 13B, twelve polarization electrodes 102311, three non-driving phase electrodes 10232, and one detection phase electrode 10233 were formed on the other surface. At this time, the distance between adjacent electrodes of each electrode shown in FIG. 13B was 0.5 mm.

  Next, a DC power supply is used between the common electrode 1022 and the polarization electrode 102311, the non-driving phase electrode 10232, and the detection phase electrode 10233 so that the expansion and contraction polarity of the piezoelectric element becomes as shown in FIG. Polarization was performed in air. The voltage was set such that an electric field of 1.0 kV / mm was applied, and the temperature and voltage application time were set to 100 ° C. and 60 minutes, respectively. In addition, the voltage was applied until the temperature reached 40 ° C. during the temperature decrease.

  Next, as shown in FIG. 13D, in order to connect the polarization electrodes 102311, a connection electrode 102312 is formed of silver paste, and by combining both types of electrodes into two drive phase electrodes 10231, piezoelectricity is achieved. The element 102 was obtained. The silver paste was dried at a temperature sufficiently lower than the depolarization temperature of the piezoelectric ceramic 1021. The resistance value of the driving phase electrode 10231 was measured by a circuit meter (electric tester). One of the testers is in contact with the surface of the portion of the polarization electrode 102311 closest to the detection phase electrode 10233, and the other is with the surface of the portion of the polarization electrode 102311 farthest in the circumferential direction of the ring shape of the drive phase electrode 10231. I did. As a result, the resistance value of the drive phase electrode 10231 was 0.6Ω.

  Next, as shown in FIG. 13E, attention is focused on a region where two driving phase electrodes 10231 of the piezoelectric element 102, two non-driving phase electrodes 10232, and a detection phase electrode 10233 are straddled. In these regions, the flexible printed circuit 3 was crimped in a room temperature process using a moisture-curable epoxy resin adhesive. The flexible printed circuit board 3 is a member provided for the purpose of feeding power to the electrode group and taking out a detection signal, and a connector portion (not shown) for connecting to the electric wiring 301, the insulating base film 302, and an external drive circuit. ).

  Next, as shown in FIG. 1A, the piezoelectric element 102 was pressure-bonded to the first surface of the diaphragm 101 by a room temperature process using a moisture-curable epoxy resin adhesive. The vibrator 101 was produced by connecting the vibrating plate 101 and the three non-driving phase electrodes 10232 with a short circuit wiring (not shown) made of silver paste. The silver paste was dried at a temperature sufficiently lower than the depolarization temperature of the piezoelectric ceramic 1021.

(Confirmation of suppression of unnecessary traveling wave of oscillator and confirmation of position of unnecessary standing wave)
Next, an alternating voltage is applied to the vibrator 1 obtained in the above manufacturing example while changing the frequency, and using an impedance analyzer and a laser Doppler vibrometer, the resonance frequency and the wave number of the generated bending vibration wave The position was evaluated.

  The measurement of the resonance frequency was performed on the A phase of the drive phase electrode 10231. First, in order to apply an alternating voltage to the A-phase electrode, the B-phase electrode and the detection phase electrode 10233 are short-circuited with the non-drive phase electrode 10232 using the connector portion of the flexible printed board 3 to evaluate the shorted portion Wired to the ground side of the external power supply.

  The impedance at room temperature was measured by applying an alternating voltage of 10 V in amplitude with variable frequency to the A-phase electrode. The frequency was changed from the high frequency side, for example 50 kHz, to the low frequency side, for example 1 kHz.

  FIG. 14 shows the result of impedance measurement at room temperature for the vibrator 1 using the piezoelectric ceramic and the diaphragm shown in the above-mentioned production example. In FIG. 14, peaks of standing waves of a plurality of orders appear, and in each order, a downward peak (resonance) and an upward peak (antiresonance) appear as a pair at close frequencies.

  Here, the minimum value of the downward peak is taken as the resonance frequency. The wave number and the position corresponding to each peak were specified by actually measuring the vibration amplitudes of all the protrusions of the diaphragm with a laser Doppler vibrometer. The method of applying the alternating voltage was the same as when measuring the impedance.

  As a result, the plurality of downward peaks seen in the impedance curve of FIG. 14 were peaks corresponding to the occurrence of the fourth, fifth, sixth, seventh and eighth standing waves due to resonance.

  Referring to FIG. 14, in the vibrator of the present invention using the diaphragm in which the center depth of the groove is changed according to the present invention, only one desired seventh-order resonance frequency appears, and the fourth order is unnecessary. The 5th, 6th and 8th resonance frequencies appeared at two different frequencies. That is, it turned out that generation | occurrence | production of an unnecessary traveling wave is suppressed with respect to generation | occurrence | production of a desired 7th order traveling wave.

  Here, in the vibrator 1, as shown in FIG. 14, since the resonance frequencies to be the fourth, fifth, sixth and eighth standing waves appear at two different frequencies, the standing frequencies of the respective orders can be obtained. We confirmed the position of the standing wave where the vibration amplitude increased with the wave.

  As a result, the fourth-order unwanted standing wave was generated at 8.4 kHz, and the position of the abdomen substantially coincided with the deep portion of the groove in FIG. 7 (a). Also, the fifth-order unwanted standing wave was generated at 13.4 kHz, and its abdomen almost coincided with the deep part of the groove in FIG. 7 (b). Also, the sixth unwanted standing wave occurred at 19.4 kHz, and its abdomen almost coincided with the deep part of the groove in FIG. 7 (c). Also, the eighth-order unwanted standing wave was generated at 33.8 kHz, and its abdomen almost coincided with the deep portion of the groove in FIG. 7 (d).

(Production Example 1 of Vibration Damping Member)
In order to produce a vibration damping member used in the present invention, an annular felt (manufactured by Toray Industries, Inc., product name: GS felt) was prepared.

  The outer diameter, the inner diameter and the thickness of the vibration damping member were 71.2 mm for the outer diameter, 67.2 mm for the inner diameter and 1 mm for the thickness.

  Next, in the prepared annular vibration damping member, for the purpose of suppressing the sixth-order unnecessary standing wave, circumferentially around the position corresponding to the deep portion of the groove in FIG. 7C. It was radially cut so as to have a length of 1/8 of the wavelength P6 of the sixth unwanted standing wave.

  In FIG. 15C, a position corresponding to 1⁄8 of the wavelength P6 of the sixth standing wave in the circumferential direction is shaded in the circumferential direction centering on the position corresponding to the deep portion of the groove in FIG. It is

  The shaded position on this graph corresponds to the abdomen of the standing wave generated when the vibration wave motor is driven and its vicinity.

  Each one of the vibration damping members G1 prepared by the above method had a fan-like shape in which the width becomes wider on the outer diameter side of the annular ring.

  The produced vibration damping member G1 was bonded to the surface on the piezoelectric element side of the vibrator 1 using a moisture curing type epoxy resin adhesive so as to be the hatched position of FIG. By disposing the vibration damping member G1 in this manner, a portion corresponding to the antinode of the unnecessary standing wave can be pressurized, and the unnecessary standing wave can be effectively suppressed.

(Production example 2 of vibration damping member)
Next, another vibration damping member G2 was manufactured by the same felt and manufacturing method as the vibration damping member G1. However, in the vibration damping member G2, the fourth order, 5 in the circumferential direction centering on the position corresponding to the deep portion of the groove in FIGS. 7 (a), 7 (b), 7 (c), 7 (d) respectively. It was radially cut to be 1/8 the wavelength of the next, sixth and eighth standing waves. The positions of the respective vibration damping members are shown by hatching in FIGS. 15 (a), 15 (b), 15 (c) and 15 (d). The shaded position on this graph corresponds to the abdomen of the standing wave generated when the vibration wave motor is driven and its vicinity.

  The vibration damping member was cut so that the vibration damping member was installed at a position where these meshed positions were superimposed. The position of the vibration damping member is shown by hatching in FIG. The solid line in FIG. 16 is the same as that in FIG. 6E, and represents the groove depth of the vibrator 1. Thus, the vibration damping member G2 was produced.

  The produced vibration damping member G2 was bonded to the surface on the piezoelectric element side of the vibrator 1 using a moisture curing type epoxy resin adhesive so as to be a hatched position in FIG. By disposing the vibration damping member G2 in this manner, it is possible to pressurize a portion corresponding to the antinode of the unnecessary standing wave, and the unnecessary standing wave can be effectively suppressed.

(Example of manufacturing a conventional vibration damping member)
Separately, in order to use the vibration wave motor of the present invention and the vibration wave motor for comparison, a vibration damping member RG1 was manufactured by the same felt and manufacturing method as the vibration damping member G1. However, it did not cut but remained as a piece of toroid.

(Production Example 1 of Pressure Member)
In order to produce a pressure member used for the vibration wave motor of the present invention, two annular SUS plates and a wave washer were prepared so as to be sandwiched therebetween. The outer diameter, inner diameter and thickness of the annular SUS plate were 71.2 mm in outer diameter, 67.2 mm in inner diameter and 1 mm in thickness. Further, the outer diameter of the ring-shaped plate spring was 71.2 mm, the inner diameter was 67.2 mm, and a plate having a hardness of 10 N and a deflection amount of 0.5 mm was prepared.

  Next, for the purpose of suppressing the sixth-order unnecessary standing wave with respect to one annular SUS plate, the shaded portion in FIG. 15 (c) has a convex portion 5021 with a height of 1 mm. The press work was done.

  Next, the pressed SUS plate, the annular plate spring, and the annular SUS plate were stacked in this order to obtain a pressure member K1.

  A moisture-curable epoxy resin is bonded to one surface of the vibration damping member RG1 so that the convex portion of the produced pressure member K1 is at the position of the abdomen of the standing wave shown in FIG. 15C of the vibrator. It adhered using the agent.

(Production Example 2 of Pressure Member)
Next, a pressing member K2 was produced by the same member and manufacturing method as the pressing member K1. However, in order to suppress unnecessary standing waves of the fourth, fifth, sixth, and eighth orders in the pressing member K2, the shaded portions in FIG. 16 have convex portions with a height of 1 mm. Press processing was performed. The produced pressure member K2 was bonded to the surface on the piezoelectric element side of the vibrator 1 using a moisture curing type epoxy resin adhesive so as to be a hatched position in FIG.

(Example of manufacture of conventional pressure member)
Separately, in order to use the vibration wave motor of the present invention and the vibration wave motor for comparison, a pressure member RK1 was manufactured by the same members and manufacturing method as the pressure member K1. However, pressing was not performed, and the SUS plate was a flat plate and no projections were provided.

(Example of manufacturing mobile)
The outer diameter, the inner diameter and the thickness of the metal plate 101a were a metal plate 101a having an outer diameter 2R of 77.0 mm, an inner diameter of 67.1 mm and a thickness of 5.0 mm.

  An annular mobile body 2 having an outer diameter of 77.0 mm, an inner diameter of 67.1 mm, and a thickness of 5 mm was manufactured for use in the vibration wave motor of the present invention and the vibration wave motor for comparison.

  Aluminum metal was used as the material of the moving body, and after the shape was trimmed by block cutting, the surface was anodized.

(Production Example and Comparative Example of Oscillatory Wave Motor)
As shown in FIG. 1A and FIG. 2, the movable body, the vibrator 1, the vibration damping member, and the pressure member are stacked in this order, and the movable body 2 is applied to the second surface of the vibrator 1 by the pressure member. Pressure contact was made to produce the vibration wave motors P, Q, R, S of the present invention. Similarly, a vibration wave motor T for comparison was produced. The pressing force was 1.5 kgf for both vibration wave motors.

  Table 2 shows combinations of vibration damping members G1, G2, RG1 and pressing members K1, K2, RK1 used in the vibration wave motor of the present invention and the vibration wave motor for comparison.

(Manufacturing example and comparative example of drive control system)
Next, using the connector portion of the flexible printed circuit board 3, the drive phase electrode 10231, the non-drive phase electrode 10232 shorted to the common electrode 1022, the detection phase electrode 10233 and the external drive circuit in the vibration wave motor of the present invention Connected electrically. Thus, the drive control system of the present invention configured as shown in FIG. 9 was produced. The external drive circuit has a control mechanism for driving the oscillatory wave motor and a signal generation mechanism for outputting an alternating voltage for generating a bending oscillatory wave of seven waves according to an instruction of the control mechanism.

  Similarly, a drive control system for comparison was prepared, and a drive test of the drive control system of the present invention and the drive control system for comparison was performed.

  A load was applied to the moving body 2 to give a load of 150 gf · cm (about 1.5 N · cm), and an alternating voltage with an amplitude of 70 V was applied to the A phase and the B phase. The frequency was fixed at 27 kHz, and was applied to the A phase and the B phase with a temporal phase difference of π / 2 in both drive control systems.

  At that time, the result of FFT analysis of the voltage signal output from the detection phase electrode is shown in Table 3. Voltage signals output when the vibration wave motor T has voltage values at the frequencies of unnecessary standing waves of four waves, five waves, six waves, and eight waves in each of the vibration wave motors P, Q, R, S, and T Expressed as a percentage change against. However, the first digit was rounded. Also, abnormal noise generated from the drive control system was also measured at this time. In the measurement of abnormal noise, the sound pressure level can be determined by analyzing data recorded by connecting an external microphone to a general frequency analyzer (for example, SA-02M manufactured by Lion Corporation). Specifically, the sound pressure level (A characteristic) with the A characteristic correction defined in Japanese Industrial Standard (JIS C 1502-1990) of the ordinary sound level meter in the frequency range of 20 Hz to 20 kHz which is the human audible range Sound pressure level was measured. Here, the A-characteristic sound pressure level is defined by the Japanese Industrial Standard, and the human auditory characteristic that the loudness of human beings differs depending on the frequency even if the sound pressure is physically the same. Frequency weighting characteristics considered. In this measurement, a microphone for measurement was placed at a position 2 cm away from the vibrator. The measured results are shown in Table 3.

  The noise during driving in the drive control system using the vibration wave motor of the present invention is suppressed as compared to the drive control system using the vibration wave motor for comparison.

(Production example of optical instrument)
The optical device shown in FIGS. 10 (a) and 10 (b) and FIG. 11 is produced by the drive control system using the vibration wave motors P, Q, R, S of the present invention, and the optical device according to the application of alternating voltage I checked the auto focus operation. No noise was generated during driving of any of the optical devices.

  According to the present invention, for example, a vibration wave motor that rotates a moving body by a seventh order bending vibration wave, which exhibits a sufficient driving speed and suppresses the generation of noise, and a motor using the vibration wave motor A drive control system and an optical instrument are provided. It is also possible to use lead-free piezoelectric ceramics with high environmental safety.

Reference Signs List 1 vibrator 101 diaphragm 101a metal plate 1011 protrusion 1012 groove 102 piezoelectric element 1021 piezoelectric ceramic 1022 common electrode 10231 driving phase electrode 102311 polarization electrode 102312 connecting electrode 10232 non-driving phase electrode 10233 detection phase electrode 2 moving body 3 flexible printed circuit board 301 Electrical wiring 302 Insulator (base film)
4 vibration damping member 5 pressure member 501 spring 502 flat plate 5021 convex part 701 front lens group 702 rear lens group (focus lens)
711 Detachable mount 712 Fixed cylinder 713 Straight guide cylinder 714 Front lens barrel 715 Cam ring 716 Rear lens barrel 717 Cam roller 718 Shaft screw 719 Roller 720 Rotation transmission ring 722 Roller 724 Manual focus ring 725 Vibration wave motor 726 Wave washer 727 Ball race 728 Focus key 729 Joint member 732 Washer 733 Low friction sheet

Claims (14)

Mobile and
A vibrator having an annular diaphragm and an annular piezoelectric element;
A vibration damping member,
Are vibration wave motors provided in order, and
The diaphragm is on the movable body side,
It has a plurality of grooves extending radially from the center of the annular diaphragm,
At least one of the plurality of grooves has a different depth,
A vibration wave motor characterized by being unevenly pressurized by the vibration damping member.   The diaphragm has radially extending groove portions at X locations on the movable body side, and when the center depths of the groove portions at the X locations are D1 to DX in order in the circumferential direction, one or more of D1 to DX are 2. The oscillatory wave motor according to claim 1, wherein the oscillatory wave motor changes along a curve obtained by superimposing sine waves.   The vibration damping member according to claim 1 or 2, wherein a part or all of the abdomen of the standing wave generated when the vibration wave motor is driven is strongly pressurized by the vibration damping member compared with other than the abdomen of the standing wave. Vibration wave motor.   The oscillatory wave motor according to claim 2, wherein the pressurization is locally increased in a part or all of the abdomen of the sine wave.   The vibration wave motor according to any one of claims 1 to 4, wherein the vibration plate and the vibration damping member are fixed to each other in circumferential arrangement.   The oscillatory wave motor according to any one of claims 1 to 5, wherein the piezoelectric element has two driving phase electrodes, a non-driving phase electrode, and a detection phase electrode.   Assuming that the length of one arc obtained by equally dividing the circumference of the annular piezoelectric element by 7 is λ, the lengths in the circumferential direction of the two drive phase electrodes are 3λ, respectively, and they are λ in the circumferential direction. 7. The device according to claim 6, wherein the non-driving phase electrode and the detection phase electrode are provided in the two spacing portions circumferentially separated from each other by two spacing portions having a length of / 4 and 3λ / 4. Vibration wave motor.   The oscillatory wave motor according to any one of claims 1 to 7, wherein the lead content of the piezoelectric material contained in the piezoelectric element is less than 1000 ppm.   The oscillatory wave motor according to any one of claims 1 to 8, wherein the piezoelectric material is a barium titanate based material.   The vibration wave motor according to any one of claims 1 to 9, wherein the contact portion between the vibration damping member and the piezoelectric element is separated into a plurality of places. And a pressing member for pressing the diaphragm to the movable body via the vibration damping member,
The oscillatory wave motor according to claim 3, wherein the pressing member has a convex portion at a position corresponding to the abdomen of the standing wave.   A drive control system comprising: the vibration wave motor according to any one of claims 1 to 11; and a drive circuit electrically connected to the vibration wave motor.   An optical apparatus comprising the drive control system according to claim 12 and an optical member supported by the vibration wave motor.   An electronic apparatus comprising the vibration wave motor according to any one of claims 1 to 11.

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