Vibration wave motor

Abstract

To provide a vibration wave motor of which the capacity is small and the drive power is large.SOLUTION: A vibration wave motor comprises: a vibrator 15 including a first elastic body 1, a second elastic body 2 and an electrical-mechanical energy conversion element 3 disposed between the first elastic body 1 and the second elastic body 2; and a mobile 16 which is moved in relative to the vibrator 15 by vibration of the vibrator 15. An outer diameter of a contact face between the first elastic body 1 and the electrical-mechanical energy conversion element 3 is smaller than a diameter of a slide face between the first elastic body 1 and the mobile 16, an inner diameter of the contact face is larger than an inner diameter of the first elastic body 1 and an inner diameter of the electrical-mechanical energy conversion element 3, and an inner diameter of an internal electrode 3-3 of the electrical-mechanical energy conversion element 3 is within ±30% of the inner diameter of the contact face.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a vibration wave motor. [Background technology]

[0002] Various configurations are known as vibration wave motors using electromechanical energy conversion elements such as piezoelectric elements. For example, as disclosed in Patent Document 1 and Patent Document 2, there is a vibration wave motor that drives a rotor, which is a moving body, by pressurizing and contacting a Langevin type vibrator configured by sandwiching a piezoelectric element between an elastic body such as stainless steel. The driving principle of this type is that by applying a predetermined AC voltage (driving voltage) to the piezoelectric element, two bending vibrations perpendicular to the vibrator are generated, causing elliptical or circular motion on the surface of the elastic body, and the moving body is rotated by frictional force.

[0003] Recently, in addition to single plate-shaped piezoelectric elements, multi-layer piezoelectric elements in which multiple piezoelectric layers and electrode layers are alternately stacked and sintered together, and elements in which single plate-shaped sintered piezoelectric elements are stacked and bonded together, are being used. This is because stacking allows for large displacement and large force to be obtained at a low voltage compared to single plate-shaped piezoelectric elements. In particular, multi-layer piezoelectric elements sintered together are suitable for miniaturization and thin layering. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 3526298 [Patent Document 2] JP 2014-54033 A Summary of the Invention [Problem to be solved by the invention]

[0005] When these vibration wave motors are applied to battery-powered portable devices such as cameras, it is desirable to operate them with low power consumption in order to minimize battery consumption. When the voltage applied to the piezoelectric element is constant, the power consumption of the drive circuit is proportional to the square of the capacitance, so it is possible to reduce power consumption by reducing the capacitance. To reduce this capacitance, there are methods to reduce the electrode area or increase the distance (thickness) between the electrodes, but increasing the thickness naturally increases the motor size. On the other hand, if the electrode area is simply reduced to reduce the capacitance, the motor size will not increase, but the force required for drive will also decrease.

[0006] The present invention has been made in consideration of the above problems, and has an object to provide a vibration wave motor that has a small capacity and a large driving force. [Means for solving the problem]

[0007] The vibration wave motor of the present invention comprises a vibrating body having a first elastic body, a second elastic body, and an electro-mechanical energy conversion element arranged between the first elastic body and the second elastic body, and a moving body that moves relative to the vibrating body due to vibration of the vibrating body, wherein the outer diameter of the contact surface between the first elastic body and the electro-mechanical energy conversion element is smaller than the diameter of the sliding surface between the first elastic body and the moving body, the inner diameter of the contact surface is larger than the inner diameter of the first elastic body and the inner diameter of the electro-mechanical energy conversion element, and the inner diameter of the internal electrode of the electro-mechanical energy conversion element is within ±30% of the inner diameter of the contact surface. Effect of the Invention

[0008] According to the present invention, a vibration wave motor having a small capacity and a large driving force is realized. [Brief description of the drawings]

[0009] [Figure 1] 1 is an exploded perspective view of a vibration wave motor according to a first embodiment. [Diagram 2] 1 is a cross-sectional view showing a vibration wave motor according to a first embodiment. [Diagram 3]1 is a perspective view showing vibration modes of a vibration wave motor according to a first embodiment. [Figure 4] 2 is a cross-sectional view showing an electrode layer of a laminated piezoelectric element in the vibration wave motor according to the first embodiment. [Diagram 5] FIG. 4 is a characteristic diagram showing the relationship between the inner diameter of the internal electrode and the force coefficient and the electrode area. [Figure 6] FIG. 11 is a characteristic diagram showing the relationship between the rotation speed and power of the vibration wave motor when d2=d1 in the vibration wave motor according to the first embodiment and when d2=2.5 mm as a comparative example. [Figure 7] FIG. 11 is a diagram illustrating an imaging device according to a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, various embodiments of the present invention will be described in detail with reference to the drawings. In the following description, components common to multiple drawings are given common reference numerals. Therefore, the common components will be described with mutual reference to multiple drawings, and the description of the components given the common reference numerals will be omitted as appropriate.

[0011] [First embodiment] The first embodiment will be described below. Fig. 1 is an exploded perspective view of the vibration wave motor according to the first embodiment. Fig. 2 is a cross-sectional view of the vibration wave motor according to the first embodiment. The basic principle of the vibration wave motor according to this embodiment will be described with reference to Figs. 1 and 2.

[0012] Reference numeral 1 denotes a first elastic body, 2 denotes a second elastic body, 3 denotes a laminated piezoelectric element which is an electro-mechanical energy conversion element, 4 denotes a flexible printed circuit board, 5 denotes a shaft, and 6 denotes a nut. The first elastic body 1, the second elastic body 2, the laminated piezoelectric element 3, and the flexible printed circuit board 4 are fastened by the shaft 5 and the nut 6 so that a predetermined clamping force is applied, forming a rod-shaped vibrator 15 which is a vibrating body.

[0013] The laminated piezoelectric element 3 includes electrode groups (phase A and phase B), each of which consists of two electrodes. When AC voltages of different phases are applied to each electrode group from a power source (not shown) via the flexible printed circuit board 4, two perpendicular bending vibrations are excited in the vibrator 15. The vibration modes are shown in FIG. 3. In FIG. 3, (a) shows the vibration mode that represents a state in which no voltage is applied, (b) shows the vibration mode bending in the X direction (left-right direction on the paper), and (c) shows the vibration mode bending in the Y direction (vertical direction on the paper).

[0014] Furthermore, by adjusting the phase of the applied AC electric field, it is possible to provide a temporal phase difference of 90° to these two vibration modes, which have a spatial phase difference of 90° around the axial direction. As a result, the bending vibration of the vibrator 15 rotates around the axis, and an elliptical motion is generated on the first elastic body 1. Then, by pressing the contact portion 7, which will be described later, against the first elastic body 1, the contact portion 7 rotates around the Z axis due to frictional force.

[0015] The contact portion 7 has a small contact area with the first elastic body 1 and is structured to have moderate springiness. The material of the contact portion 7 is preferably stainless steel having wear resistance, strength, and corrosion resistance, and a more preferable specific example is SUS420J2. It can be processed using a lathe or a 3D printer, but press processing is preferable in terms of processing accuracy and cost. The contact portion 7 is fixed to the rotor ring 8 by adhesion with a resin adhesive, metal brazing such as solder, welding such as laser welding or resistance welding, or mechanical joining such as press fitting or crimping, and constitutes a moving body 16 that moves relatively to the vibrator 15.

[0016] The rotor ring 8 is pressurized by a pressure spring 10 via rubber 9. By applying pressure in this manner, a frictional force is generated between the contact portion 7 and the first elastic body 1, and the contact portion 7 can be driven by the above-mentioned elliptical motion. The rubber 9 functions to equalize the pressure force while attenuating unnecessary vibrations of the spring 9 and the rotor ring 8.

[0017] A gear 11 that transmits output to the outside is provided on the upper part of the rotor ring 8, and a recess is formed on the upper surface of the rotor ring 8, which engages with a protrusion formed on the gear 11. As described above, the contact part 7 rotates around the Z axis due to the elliptical motion and frictional force on the first elastic body 1. As a result, the rotor ring 8 fixed to the contact part 7, the gear 11 engaged with the rotor ring 8, and the pressure spring 10 and rubber 9 sandwiched between them rotate together around the Z axis, and the gear 11 transmits output to the outside. Since the gear 11 slides against the flange cap 12 while being subjected to pressure, a material that satisfies strength and wear resistance is preferable, and a resin containing reinforced fibers is most preferable in consideration of cost and quietness.

[0018] The vibrator 15 is fixed to the flange 13, which is a fixed member, by the shaft 5 and the nut 14. Between the gear 11 and the flange 13, a flange cap 12, which is a pressure receiving member, is provided. The flange cap 12 may be fixed to the flange 13 by adhesive or the like. The material of the flange cap 12 is preferably a material that is wear resistant. Stainless steel press processing is more preferable because it has good dimensional accuracy and good productivity. In addition, since the flange 13 has a complex shape, it is made by resin molding, zinc die casting, aluminum die casting, or metal sintering. In this embodiment, zinc die casting is used, which has an excellent balance between dimensional accuracy and cost. The gear 11 and the flange cap 12 slide in the axial direction, and the gear 11 and the flange 13 slide in the radial direction, serving as a sliding bearing.

[0019] FIG. 4 is a cross-sectional view showing electrode layers of a laminated piezoelectric element in the vibration wave motor of this embodiment. In the laminated piezoelectric element 3, active layers, which are polarized piezoelectric bodies, and electrode layers having internal electrodes 3-3 are alternately laminated in the Z direction, and inactive layers, which are non-polarized piezoelectric bodies, are provided on the bottom and top surfaces. The internal electrodes 3-3 are divided into a plurality of parts, for example, four parts in FIG. 4, and the parts not covered by the internal electrodes 3-3 are inactive parts 3-2. The upper and lower internal electrodes 3-3 are electrically connected by through-hole electrodes (through-hole electrodes) 3-4. Specifically, the through-hole electrodes 3-4 provided in the internal electrodes 3-3 in FIG. 4 pass through the inactive parts 3-2 of the electrode layers adjacent to each other through the active layers, the internal electrodes 3-3 of the electrode layers adjacent to each other through the active layers, etc., in order, and electrically connect these internal electrodes 3-3. The through-hole electrodes 3-4 provided in the inactive parts 3-2 in FIG. 4 pass through the internal electrodes 3-3 of the electrode layers adjacent to each other through the active layers, the inactive parts 3-2 of the electrode layers adjacent to each other through the active layers, etc., in order, and electrically connect these internal electrodes 3-3.

[0020] The active layer is polarized by applying a DC voltage to the internal electrodes 3-3 during manufacture, and when driven, an AC voltage is applied to the internal electrodes 3-3, causing the active layer to expand and contract in the Z direction due to the inverse piezoelectric effect, exciting the above-mentioned vibration.

[0021] To manufacture the laminated piezoelectric element 3, first, a green sheet that will become the piezoelectric layer is made from piezoelectric material and an organic binder by the doctor blade method, and then the internal electrode 3-3 made of electrode material paste is formed at a predetermined position on this green sheet by screen printing. A predetermined number of these green sheets are then stacked on a flat surface and laminated under pressure, and the piezoelectric layer and electrode layer are integrated and fired, after which a polarization process is performed and the product is finished by double-sided lapping.

[0022] In this embodiment, a laminated piezoelectric element is used, but a single-plate piezoelectric element having a pair of electrodes formed on the front and back of a piezoelectric body may be used. Also, the shape of the laminated piezoelectric element 3 in this embodiment is a rectangular parallelepiped, but it may be, for example, a cylindrical shape.

[0023] Here, as shown in FIG. 2, the inner diameter of the contact surface between the first elastic body 1 and the laminated piezoelectric element 3 is d1, and the outer diameter is D1. The first elastic body 1 has an annular convex portion 1a on its surface, and the convex portion 1a is in contact with the laminated piezoelectric element 3. The outer diameter of the convex portion 1a, i.e., the outer diameter D1 of the contact surface between the first elastic body 1 and the laminated piezoelectric element 3, is smaller than the diameter (sliding diameter) of the sliding surface between the first elastic body 1 and the moving body 16. The inner diameter of the convex portion 1a, i.e., the inner diameter d1 of the contact surface between the first elastic body 1 and the laminated piezoelectric element 3, is larger than the inner diameter of the first elastic body 1 (the diameter of the insertion hole of the shaft 5 formed in the first elastic body 1) and the inner diameter of the laminated piezoelectric element 3 (the diameter of the insertion hole of the shaft 5 formed in the laminated piezoelectric element 3). In this way, the first elastic body 1 and the laminated piezoelectric element 3 are not in contact with each other over the entire surface, and are configured to have clearance at the inner diameter and the outer diameter. This makes it possible, when the laminated piezoelectric element 3 is sandwiched between the first elastic body 1 and the second elastic body 2, to ensure that the laminated piezoelectric element 3 is in close contact with the protrusion 1a from the inner edge to the outer edge, which is the contact point with the laminated piezoelectric element 3.

[0024] In a drive type drive device that drives an oscillatory wave motor, the heat loss P on the primary side of the transformer circuit is 1 It is proportional to the square of and can be expressed by the following formula. P ∝ (I 1 ) 2 ...Equation (1) Also, if the applied voltage is V and the capacitance is C, the above equation can be transformed into the following: I 1 ∝(C×V)...Equation (2) P ∝ (C × V) 2 ...Equation (3)

[0025] When the applied voltage is constant, the smaller the capacity, the more heat loss can be reduced. In order to reduce the capacity, it is necessary to reduce the electrode area or increase the thickness of the active layer, but increasing the active thickness increases the overall length of the vibration wave motor. On the other hand, simply reducing the electrode area reduces the force that can be generated, so it is necessary to increase the applied voltage to compensate. For example, if the electrode area is halved, the capacity is halved (C÷2), but the force generated is also halved, and twice the voltage (2×V) is required. Applying this to equation (3), the heat loss P remains the same value.

[0026] In this embodiment, in order to realize a vibration wave motor with a small capacity and a large driving force, the inventors have conceived of enlarging the inner diameter of the internal electrode of the electromechanical energy conversion element and reducing the electrode area while suppressing the decrease in the force coefficient. This point will be described below. As shown in Figure 4, the inner diameter of the internal electrode 3-3 is d2 and the outer diameter is D2. Figure 5 is a characteristic diagram showing the relationship between the inner diameter d2 and the force coefficient and electrode area. The force coefficient is the force generated by the vibrator per applied voltage, and the larger this value is, the greater the force generated at a constant voltage. In Figure 5, the outer diameter of the internal electrode 3-3 is fixed, and the force coefficient and electrode area are normalized to 1 when d2 is φ2.5 mm.

[0027] First, the electrode area naturally decreases in proportion to the increase in the inner diameter d2 of the internal electrode. Since the capacitance is proportional to the electrode area, the capacitance also decreases at the same rate. On the other hand, the force coefficient decreases less than the electrode area from φ2.5mm to d1 (approximately φ3.7mm), and in the region larger than d1, the force coefficient decreases more than the electrode area. That is, the closer the inner diameter d2 of the internal electrode 3-3 is to the inner diameter d1 of the contact surface between the first elastic body 1 and the piezoelectric element 3 (the smaller the absolute value of the difference between d1 and d2 (|d1-d2|)), the greater the difference between the force coefficient and the electrode area. By making the inner diameter d1 and the inner diameter d2 equal, the difference between the force coefficient and the electrode area can be maximized. In this state, the capacitance can be reduced without significantly increasing the applied voltage, and therefore the circuit loss can be significantly reduced.

[0028] In this embodiment, based on the above findings, the inner diameter d2 of the internal electrode of the electromechanical energy conversion element is made close to the inner diameter d1 of the contact surface between the first elastic body 1 and the laminated piezoelectric element 3. Specifically, the inner diameter d2 is determined so that the difference with the inner diameter d1 is within ±30% (in other words, (|d1-d2| / d1)×100≦30(%)). If the difference between d1 and d2 is within ±30%, it can be evaluated that a sufficient reduction in circuit loss is obtained.

[0029] Here, since the difference between the force coefficient and the electrode area increases gradually as the inner diameter d2 approaches the inner diameter d1, it is possible to further narrow the difference between the inner diameters d1 and d2. For example, it is preferable to determine the inner diameter d2 so that the difference from the inner diameter d1 is within a narrower range, for example, within ±10% (in other words, (|d1-d2| / d1)×100≦10(%)). This provides the effect of further reducing circuit loss. Furthermore, by making the inner diameter d2 equal to the inner diameter d1 (d2=d1), the difference between the force coefficient and the electrode area is maximized, and the circuit loss can be reduced to the maximum.

[0030] On the inner diameter side of the inner diameter d1, i.e., the portion where the first elastic body 1 and the laminated piezoelectric element 3 are not in contact, the Z-direction distortion of the laminated piezoelectric element 3 is small, so it does not contribute to the generation of force and cannot effectively excite the piezoelectric element 3. The difference in the rate of change between the electrode area and the force coefficient as described above occurs because the decrease in the force coefficient is small even if the corresponding portion of the internal electrode is reduced.

[0031] FIG. 6 is a characteristic diagram showing the relationship between the rotation speed and the power of the vibration wave motor when d2=d1 in the vibration wave motor of this embodiment and when d2=2.5 mm as a comparative example. In this embodiment, since the capacity is reduced compared to the comparative example, it can be seen that the power is reduced over the entire range of rotation speeds. In particular, at low speeds, a large amount of current tends to flow through the drive circuit, resulting in a significant reduction in power.

[0032] In the vibration wave motor of this embodiment, the inner diameter of the internal electrode of the electromechanical energy conversion element is enlarged to reduce the electrode area. As shown in FIG. 4, by enlarging the inner diameter d1 of the internal electrode 3-3, a recess 3-3a is formed in the active region (active part) of the internal electrode 3-3, leaving the part where the through-hole electrode 3-4 is formed on the inner edge (edge ​​part forming the inner diameter) of the internal electrode 3-3. The recess 3-3a is a part of the inner edge of the internal electrode 3-3 that is recessed toward the outer edge (edge ​​part forming the outer diameter). In the active region, a narrow part is formed by the recess 3-3a according to the amount of enlargement of the inner diameter d2. The inner diameter and outer diameter of the internal electrode 3-3 are determined in this narrow part, and the through-hole electrode 3-4 is located in the inactive part 3-2 located inside the inner edge of the internal electrode 3-3.

[0033] In this manner, in the vibration wave motor of this embodiment, the inner diameter of the internal electrode 3-3 is enlarged to such an extent that the through-hole electrode 3-4 is located inside the inner edge, and the electrode area is reduced, so that the difference between the force coefficient and the electrode area is set large. In this case, the capacitance can be reduced without significantly increasing the applied voltage, so that the circuit loss can be significantly reduced. Furthermore, since the through-hole electrode 3-4 and its surrounding area are inactive areas that cannot be polarized, arranging the through-hole electrode 3-4 in the inactive area 3-2 also contributes to the effective use of the available space.

[0034] Here, the inner diameter of the contact surface between the second elastic body 2 and the laminated piezoelectric element 3 is located on the inner diameter side of the through-hole electrode 3-3. This allows the through-hole electrode 3-4 to be in contact with the flexible printed circuit board 4 reliably.

[0035] As described above, according to the present embodiment, a vibration wave motor with a small capacity and a large driving force is realized by appropriately expanding the inner diameter of the internal electrode of the electromechanical energy conversion element and reducing the electrode area while suppressing the decrease in the force coefficient. This vibration wave motor enables efficient driving while reducing the manufacturing cost.

[0036] [Second embodiment] The second embodiment will now be described. The oscillatory wave motor can be used for driving a lens that is a component of an optical device or electronic device, for example, an imaging device. In this embodiment, an imaging device that uses the oscillatory wave motor disclosed in the first embodiment for driving a lens arranged in a lens barrel will be described as an example.

[0037] FIG. 7 is a diagram showing an imaging device according to a second embodiment, where (a) is a top view showing a schematic configuration of the imaging device, and (b) is a block diagram for explaining the functional configuration of the imaging device. As shown in Fig. 7(a), the imaging device 700 includes a camera body 730 equipped with an imaging element 710 and a power button 720. The imaging device 700 also includes a lens barrel 740 having a first lens group (not shown), a second lens group 320, a third lens group (not shown), a fourth lens group 340, and vibration type driving devices 620, 640. The lens barrel 740 is replaceable as an interchangeable lens, and a lens barrel 740 suitable for a subject to be photographed can be attached to the camera body 730. In the imaging device 700, the second lens group 320 and the fourth lens group 340 are driven by the two vibration type driving devices 620, 640, respectively.

[0038] Although the detailed configuration of the vibration type driving device 620 is not shown, the vibration type driving device 620 has the vibration wave motor disclosed in the first embodiment and a driving circuit for the vibration wave motor. The rotor, which is the moving body 16 composed of the contact portion 7 and the rotor main ring 8, is disposed in the lens barrel 740 so that the radial direction is approximately perpendicular to the optical axis. In the vibration type driving device 620, the rotor is rotated around the optical axis, and the rotation output of the contact body is converted into linear motion in the optical axis direction via gears (not shown), thereby moving the second lens group 320 in the optical axis direction. The vibration type driving device 640 has a configuration similar to that of the vibration type driving device 620, and moves the fourth lens group 340 in the optical axis direction.

[0039] 7(b), the first lens group 3a0, the second lens group 320, the third lens group 330, the fourth lens group 340, and the light amount adjustment unit 350 are disposed at predetermined positions on the optical axis inside the lens barrel 740. Light that passes through the first lens group 3a0 to the fourth lens group 340 and the light amount adjustment unit 350 forms an image on the imaging element 710. The imaging element 710 converts the optical image into an electrical signal and outputs it, and the output is sent to the camera processing circuit 750.

[0040] The camera processing circuit 750 performs amplification, gamma correction, and the like on the output signal from the image sensor 710. The camera processing circuit 750 is connected to the CPU 790 via an AE gate 755, and is also connected to the CPU 790 via an AF gate 760 and an AF signal processing circuit 765. The video signal that has been subjected to a predetermined process in the camera processing circuit 750 is sent to the CPU 790 via the AE gate 755, the AF gate 760, and the AF signal processing circuit 765. The AF signal processing circuit 765 extracts high frequency components from the video signal to generate an evaluation value signal for autofocus (AF), and supplies the generated evaluation value to the CPU 790.

[0041] The CPU 790 is a control circuit that controls the overall operation of the imaging device 700, and generates control signals for determining exposure and adjusting focus from the acquired video signal. The CPU 790 adjusts the optical axis positions of the second lens group 320, the fourth lens group 340, and the light amount adjustment unit 350 by controlling the driving of the vibration type driving devices 620, 640 and the meter 630 so as to obtain the determined exposure and an appropriate focus state. Under the control of the CPU 790, the vibration type driving device 620 moves the second lens group 320 in the optical axis direction, the vibration type driving device 640 moves the fourth lens group 340 in the optical axis direction, and the light amount adjustment unit 350 is driven and controlled by the meter 630.

[0042] The optical axis direction position of the second lens group 320 driven by the vibration type driving device 620 is detected by a first linear encoder 770, and the detection result is notified to the CPU 790, thereby being fed back to the driving of the vibration type driving device 620. Similarly, the optical axis direction position of the fourth lens group 340 driven by the vibration type driving device 640 is detected by a second linear encoder 775, and the detection result is notified to the CPU 790, thereby being fed back to the driving of the vibration type driving device 640. The optical axis direction position of the light amount adjustment unit 350 is detected by an aperture encoder 780, and the detection result is notified to the CPU 790, thereby being fed back to the driving of the meter 630.

[0043] According to this embodiment, an imaging device equipped with a vibration wave motor having a small capacity and a large driving force is realized. The vibration wave motor according to the first embodiment can be applied to various members as targets to be driven by the vibration wave motor other than the imaging device, and can be suitably applied to various optical devices and electronic devices.

[0044] The disclosure of this embodiment includes the following configuration. (Configuration 1) A first elastic body and a second elastic body, an electromechanical energy conversion element disposed between the first elastic body and the second elastic body; A vibrating body having a moving body that moves relative to the vibrating body due to vibration of the vibrating body; Equipped with an outer diameter of a contact surface between the first elastic body and the electromechanical energy conversion element is smaller than a diameter of a sliding surface between the first elastic body and the moving body; an inner diameter of the contact surface is larger than an inner diameter of the first elastic body and an inner diameter of the electromechanical energy conversion element; The inner diameter of the internal electrode of the electromechanical energy conversion element is within ±30% of the inner diameter of the contact surface; A vibration wave motor characterized by: (Configuration 2) The inner diameter of the internal electrode is within ±10% of the inner diameter of the contact surface. 2. The oscillatory wave motor according to claim 1. (Configuration 3) The inner diameter of the internal electrode is equal to the inner diameter of the contact surface. 2. The oscillatory wave motor according to claim 1. (Configuration 4) the first elastic body has a protrusion, The contact surface is a contact portion between the protrusion and the electromechanical energy conversion element. 2. The oscillatory wave motor according to claim 1. (Configuration 5) The electromechanical energy conversion element has a through electrode formed in the internal electrode, The through electrode is located inside the inner edge of the internal electrode. The oscillatory wave motor according to any one of the first to fourth aspects. (Configuration 6) the electromechanical energy conversion element is a laminated piezoelectric element in which the internal electrodes and piezoelectric bodies are alternately laminated, The through electrodes electrically connect the internal electrodes of the upper and lower layers. 6. The oscillatory wave motor according to claim 5. (Configuration 7) 7. The oscillatory wave motor according to any one of configurations 1 to 6, wherein the internal electrode has a narrow width portion in which a recess is formed on part of an inner edge of the active region toward an outer edge. (Configuration 8) A first elastic body and a second elastic body, an electromechanical energy conversion element disposed between the first elastic body and the second elastic body; A vibrating body having a moving body that moves relative to the vibrating body due to vibration of the vibrating body; Equipped with The electromechanical energy conversion element has a through electrode formed in the internal electrode, The through electrode is located inside the inner edge of the internal electrode. A vibration wave motor characterized by: (Configuration 9) the internal electrode has a narrow portion in which a recess is formed in a part of an inner edge toward an outer edge in an active region; 9. The oscillatory wave motor according to claim 8. (Configuration 10) Lenses and The vibration wave motor according to any one of configurations 1 to 9, which drives the lens; Optical instrument with. (Configuration 11) The material, A vibration wave motor according to any one of configurations 1 to 9 for driving the member; Electronic equipment equipped with [Explanation of symbols]

[0045] 1: First elastic body 2: Second elastic body 3: Multilayer piezoelectric element 3-2: Inactive part 3-3: Internal electrode 3-3a: Recess 3-4: Through-hole electrode 4: Flexible printed circuit board 5: Shaft 6: Nut 7: Contact part 8: Rotor main ring 9: Rubber 10: Pressure spring 11: Gear 12: Flange cap 13: Flange 14: Upper nut 15: Transducer 16: Mobile

Claims

1. A first elastic body and a second elastic body, an electromechanical energy conversion element disposed between the first elastic body and the second elastic body; A vibrating body having a moving body that moves relative to the vibrating body due to vibration of the vibrating body; Equipped with an outer diameter of a contact surface between the first elastic body and the electromechanical energy conversion element is smaller than a diameter of a sliding surface between the first elastic body and the moving body; an inner diameter of the contact surface is larger than an inner diameter of the first elastic body and an inner diameter of the electromechanical energy conversion element; The inner diameter of the internal electrode of the electromechanical energy conversion element is within ±30% of the inner diameter of the contact surface. A vibration wave motor characterized by:

2. The inner diameter of the internal electrode is within ±10% of the inner diameter of the contact surface.

2. The oscillatory wave motor according to claim 1.

3. The inner diameter of the internal electrode is equal to the inner diameter of the contact surface.

2. The oscillatory wave motor according to claim 1.

4. The first elastic body has a protrusion, The contact surface is a contact portion between the protrusion and the electromechanical energy conversion element.

2. The oscillatory wave motor according to claim 1.

5. The electromechanical energy conversion element has a through electrode formed in the internal electrode, The through electrode is located inside the inner edge of the internal electrode.

2. The oscillatory wave motor according to claim 1.

6. the electromechanical energy conversion element is a laminated piezoelectric element in which the internal electrodes and piezoelectric bodies are alternately laminated, The through electrodes electrically connect the internal electrodes of the upper and lower layers.

6. The oscillatory wave motor according to claim 5.

7. the internal electrode has a narrow portion in which a recess is formed in a part of an inner edge toward an outer edge in an active region; 2. The oscillatory wave motor according to claim 1.

8. Lenses and A vibration wave motor according to any one of claims 1 to 7 that drives the lens; Optical instrument with.

9. The material, A vibration wave motor according to any one of claims 1 to 7 for driving the member; Electronic equipment equipped with

Images