JP2014017909A - Vibration wave motor and lens barrel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vibration wave motor which has a simple structure and can be driven by low voltage.SOLUTION: A vibration wave motor 1 includes: a laminated body 11 of electromechanical conversion elements generating vibrations by a driving signal; an elastic body 12 having a joint surface 12f joined with the laminated body, and a driving surface 12a provided on the opposite side of the joint surface and generating progressive vibration waves by vibrations; and a relatively moving member 20 press-contacted with the driving surface and driven by the vibration waves. The laminated body is made by laminating a plurality of single layer bodies 111 of the electromechanical conversion element in a thickness direction of the elastic body 12. When the laminated body is viewed from one surface side parallel with the joint surface, exposed portions 40b and 40c which are not superimposed with the front single layer bodies and exposing surfaces exist on the rear single layer bodies. The exposed portions continue in a step shape, and conductive portions 18a and 18b between the single layer bodies are formed on the continuing exposed portions.

Description

  The present invention relates to a vibration wave motor and a lens barrel.

  A vibrator of a vibration wave motor used for a lens or the like of a photographing apparatus is generally composed of a metal elastic body and a piezoelectric body, and the piezoelectric body is generally a single layer. In order to drive an ultrasonic motor using such a single-layer piezoelectric element with a practical output, a high frequency voltage of several tens of volts is required. For this reason, the voltage of the battery of the photographing apparatus is not sufficient, and there are some equipped with a booster circuit. However, since the booster circuit raises the problem of cost increase and device enlargement, there is also a vibration wave motor that secures a high voltage by stacking piezoelectric bodies (see Patent Document 1).

JP-A-7-213081

  However, the laminated piezoelectric material described in the above document is complicated because the electrode pattern of each layer is different. Another problem is that the layer bonded to the elastic body and the anti-bonding layer are not polarized, and these unpolarized layers inhibit excitation of vibration waves.

  An object of the present invention is to provide a vibration wave motor and a lens barrel that can be driven with a simple configuration and a low voltage.

The present invention solves the above problems by the following means. In addition, in order to make an understanding easy, although the code | symbol corresponding to embodiment of this invention is attached | subjected and demonstrated, it is not limited to this.
According to the first aspect of the present invention, the laminate (11, 11 ′, 213) of electromechanical transducers in which vibration is generated by a drive signal and the junction joined to the laminate (11, 11 ′, 213). An elastic body (12, 214) having a surface (12f) and a drive surface (12a) that is provided on the opposite side of the joint surface (12f) and generates a progressive vibration wave by the vibration; and the drive surface ( 12a) and a relative motion member (20, 220) driven by the vibration wave, and the laminate (11, 11 ′, 213) is a single layer of the electromechanical transducer. A plurality of (111, 111a, 111b, 111c) are stacked in the thickness direction of the elastic body (12, 214), and the stacked body (11, 11 ′, 213) is bonded to the bonding surface (12f). ) When viewed from one side parallel to In the rear monolayer (111, 111a, 111b, 111c), there are exposed portions (40b, 40c) whose surfaces are exposed without overlapping the front monolayer (111, 111a, 111b, 111c). The exposed portions (40b, 40c) are continuous in a stepped manner, and the conductive portions (18a, 18b) between the single-layer bodies (111, 111a, 111b, 111c) are connected to the continuous exposed portions (40b, 40c). The vibration wave motor (1, 210) is characterized by being formed.
According to a second aspect of the present invention, in the vibration wave motor (1, 210) according to the first aspect, the single layer body (111, 111a, 111b, 111c) has an annular shape, and the exposed portion (40b) , 40 c) are vibration wave motors (1, 210) characterized in that they are formed on the outer peripheral side or inner peripheral side of the ring.
According to a third aspect of the present invention, in the vibration wave motor (1, 210) according to the first or second aspect, the single-layer body (111, 111a, 111b, 111c) has a diameter on the outer peripheral side or the inner peripheral side. A vibration wave characterized in that the exposed portions (40b, 40c) are formed stepwise by laminating the single layer bodies (111, 111a, 111b, 111c) having different diameters. Motor (1,210).
According to a fourth aspect of the present invention, in the vibration wave motor (1, 210) according to the first or second aspect, each of the single layer bodies (111, 111a, 111b, 111c) has a first notch ( 50), and when the single layer body (111, 111a, 111b, 111c) is laminated, the position of the first notch (50) is shifted from each other, so that the exposed portion is stepped. The vibration wave motor (1, 210) is characterized in that it is formed as follows.
According to a fifth aspect of the present invention, in the vibration wave motor (1, 210) according to the fourth aspect, the first cutout portion (50) is provided in the single layer body (111, 111a, 111b, 111c). A second notch portion (51) different from the first notch portion (51) is provided, and the distance between the first notch portion (50) and the second notch portion (51) is determined by the single layer body (111, 111a, 111b, 111c), and when the single layered body (111, 111a, 111b, 111c) is laminated, the single layer is arranged such that the second notch (51) is aligned in the thickness direction. By arranging the bodies (111, 111a, 111b, 111c), the exposed portions (40b, 40c) are formed stepwise at the edge of the first notch (1). 210).
A sixth aspect of the present invention is a lens barrel including the vibration wave motor according to any one of the first to fifth aspects.

  Note that the configuration described with reference numerals may be modified as appropriate, and at least a part of the configuration may be replaced with another component.

  According to the present invention, it is possible to provide a vibration wave motor that can be driven with a simple configuration and a low voltage.

It is a figure explaining the vibration wave motor of 1st Embodiment of this invention. It is a block diagram explaining the drive device of the vibration wave motor of 1st Embodiment. It is a figure which shows the lens barrel which mounts the vibration wave motor of 1st Embodiment. It is a figure explaining the piezoelectric material of a 1st embodiment, (a) is a side view of a piezoelectric material, (b) is a figure showing the surface of a piezoelectric material, (c) A sectional view of a piezoelectric material, (d) is a figure. It is the figure which showed the back surface of the piezoelectric material. It is a figure explaining the elastic body containing a piezoelectric material, (a) is a side view, (b) is the figure seen from the surface side. It is a figure explaining the electrode pattern of each single layer piezoelectric material, (a) is the figure which showed the electrode pattern of the front and back of each single layer piezoelectric material, (b) is each single layer piezoelectric material in a laminated piezoelectric material It is the figure which showed the polarization direction. It is an enlarged view of the stepped part of a laminated piezoelectric material, (a) is a part where a conductive part of a later-described common electrode is provided, and (b) is a part of a part where a conductive part of a later-described application electrode is provided. FIG. It is the figure which showed the expansion-contraction of the piezoelectric material by an applied voltage, (a) is a figure which showed the case where an applied voltage is positive, (b) is the case where an applied voltage is negative. It is a figure explaining the piezoelectric material of 2nd Embodiment, (a) is a side view of a piezoelectric material, (b) is a figure which showed the surface of the piezoelectric material, (c) is sectional drawing of a piezoelectric material, (d) Is a diagram showing the back surface of the piezoelectric body, (e) is an enlarged view of a portion surrounded by a dotted circle in (b). It is a figure explaining the lens-barrel of 3rd Embodiment of this invention.

(First embodiment)
Hereinafter, embodiments of a vibration wave motor 1 according to the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a diagram illustrating a vibration wave motor 1 according to a first embodiment of the present invention.
In this embodiment, the vibrator 10 side is fixed, and the movable element (relative motion member) 20 is driven.
The mover 20 is made of a light metal such as aluminum, and the surface of the sliding surface is subjected to surface treatment for improving wear resistance.

  As will be described later, the vibrator 10 includes an electromechanical transducer (hereinafter referred to as a piezoelectric body) 11, such as a piezoelectric element or an electrostrictive element that converts electrical energy into mechanical energy, and the piezoelectric body 11. And an elastic body 12 bonded to each other, and a progressive vibration wave is generated in the vibrator 10.

The elastic body 12 is made of a metal material having a high resonance sharpness, and has an annular shape.
The piezoelectric body 11 is bonded to one surface (bonding surface 12f) of the elastic body 12, and a groove 12b is cut on the opposite side to the one surface. Then, the tip of the protruding portion (location without the groove 12 b) 12 c becomes the driving surface 12 a and is brought into pressure contact with the moving element 20.
The portion of the elastic body 12 where the groove 12b is not cut is a base portion 12d, and a flange 12e extends from the base portion 12d to the inner diameter side. The innermost diameter portion of the flange 12 e is fixed to the fixing member 13.
The protruding portion 12c of the elastic body 12 is provided with a sliding member such as a coating film or lubricating plating so as to cover the whole.

As will be described in detail later, the piezoelectric body 11 is provided with electrodes on the surface opposite to the adhesive surface of the elastic body 12 (the FPC side surface, the anti-bonding surface, hereinafter this surface is referred to as the surface). It has a two-group structure divided into two phases (A phase and B phase) along the circumferential direction.
In each phase, electrodes are arranged so that they are alternately polarized every ½ wavelength, and an interval of ¼ wavelength is provided between the A phase and the B phase.

The output shaft 21 is coupled to the mover 20 via a stopper member 23 inserted so as to fit the rubber member 22 and the D-cut of the output shaft 21. The output shaft 21 and the stopper member 23 are fixed by an E clip 24 or the like, and are rotated integrally with the mover 20.
The rubber member 22 between the stopper member 23 and the mover 20 has a function of coupling with the mover 20 and the stopper member 23 due to adhesiveness of rubber, and does not transmit vibration from the mover 20 to the output shaft 21. Butyl rubber having a function of absorbing vibration is preferable.
The pressure member 25 is provided between the output gear 41 of the output shaft 21 and the bearing 27. With such a structure, the moving element 20 is in pressure contact with the drive surface 12 a of the elastic body 12.

FIG. 2 is a block diagram illustrating the driving device 30 of the vibration wave motor 1 according to the first embodiment.
First, the drive / control unit 31 of the vibration wave motor 1 will be described.
The oscillating unit 32 generates a drive signal having a desired frequency according to a command from the control unit 31.
The phase shifter 33 divides the drive signal generated by the oscillator 32 into two drive signals having different phases.

The amplifying unit 34 boosts the two drive signals divided by the phase shift unit 33 to respective desired voltages.
A drive signal from the amplifying unit 34 is transmitted to the vibration wave motor 1, and a traveling wave is generated in the vibrator 10 by the application of the drive signal, so that the movable element 20 is driven.
The rotation detection unit 35 is configured by an optical encoder, a magnetic encoder, or the like, detects the position or speed of a driven object driven by driving the moving element 20, and transmits the detected value to the control unit 31 as an electric signal.

  The control unit 31 controls driving of the vibration wave motor 1 based on a drive command from the CPU 36 in the lens barrel 110 or the camera body. The control unit 31 receives the detection signal from the rotation detection unit 35, obtains position information and speed information based on the values, and controls the frequency of the oscillation unit 32 so as to be positioned at the target position.

Next, the operation of the vibration wave motor 1 of the first embodiment will be described.
When a drive command is issued from the control unit 31, the oscillation unit 32 generates a drive signal.
The drive signal is divided into two drive signals having a phase difference of 90 degrees by the phase shifter 33, and is amplified to a desired voltage by the amplifier 34.
The amplified drive signal is applied to the piezoelectric body 11 of the vibration wave motor 1, and the piezoelectric body 11 is excited (vibrated). Due to the excitation of the piezoelectric body 11, fourth-order bending vibration is generated in the elastic body 12. The piezoelectric body 11 is divided into an A phase and a B phase, and drive signals are applied to the A phase and the B phase, respectively.

  The positional phase of the quaternary bending vibration generated from the A phase and the quaternary bending vibration generated from the B phase are shifted by ¼ wavelength. In addition, since the phase A drive signal and the phase B drive signal are 90 degrees out of phase, the two bending vibrations are combined into four traveling waves.

Elliptic motion occurs at the front of the traveling wave. Therefore, the movable element 20 that is in pressure contact with the drive surface 12a is frictionally driven by this elliptical motion.
An optical encoder is arranged in the driving body driven by driving the moving element 20, and an electric pulse is generated therefrom and transmitted to the control unit 31. Based on this signal, the control unit 31 can obtain the current position and the current speed.

FIG. 3 is a diagram illustrating the lens barrel 110 on which the vibration wave motor 1 according to the first embodiment is mounted.
The vibration wave motor 1 is attached to the gear unit module 113, and the gear unit module 113 is attached to the fixed barrel 114 of the lens barrel 110.
The rotational motion of the output gear 41 of the vibration wave motor 1 is transmitted to the cam ring 116 via the reduction gear 115 of the gear unit module 113, and the cam ring 116 is driven to rotate.
A key groove 117 is cut obliquely with respect to the circumferential direction in the cam ring 116, and the AF ring 119 in which the fixing pin 118 is inserted into the key groove 117 is rotated by the cam ring 116, It is driven in the straight direction in the direction of the axis OA and can stop at a desired position.
The circuit 121 is provided between the outer fixed cylinder 114a and the inner fixed cylinder 114b of the lens barrel 110, and performs driving and control of the vibration wave motor 1, detection of the rotational speed, detection of the vibration sensor, and the like.

Next, the piezoelectric body 11 will be described in detail.
FIG. 4 is a diagram illustrating the piezoelectric body 11 according to the first embodiment. FIG. 4A is a part of a side view of the piezoelectric body 11 (viewed from a direction orthogonal to the pressing direction of the vibration wave motor 1). FIG. 4B is a view showing the surface 11A of the piezoelectric body 11, and FIG. 4A is a view seen from the aa direction of FIG. FIG.4 (c) is cc sectional drawing of (b). FIG. 4D is a view showing the back surface 11 </ b> B of the piezoelectric body 11.
FIG. 5 is a diagram illustrating the vibrator 10 including the piezoelectric body 11 and the elastic body 12. Fig.5 (a) is a side view, FIG.5 (b) is the figure seen from the surface side.

The substrate of the piezoelectric body 11 is composed of lead zirconate titanate called PZT, or barium titanate, bismuth sodium titanate, bismuth potassium titanate, etc. which are lead-free materials in recent years due to environmental problems.
Electrodes are arranged on the surface 11A of the substrate of the piezoelectric body 11, and a silver paste is printed thereon. The electrode may be a metal plating such as NiP or gold.

Further, as shown in FIGS. 4A, 4C, and 5, the piezoelectric body 11 includes a single-layer piezoelectric body 111 (a first-layer piezoelectric body 111a, a second-layer piezoelectric body 111b, and a third-layer piezoelectric body 111c. ) Are stacked in multiple layers (three layers in this embodiment). Hereinafter, in order to distinguish the piezoelectric body 11 from the single-layer piezoelectric body 111, the multilayer piezoelectric body 11 is appropriately referred to.
The first-layer piezoelectric body 111a, the second-layer piezoelectric body 111b, and the third-layer piezoelectric body 111c are arranged in this order from the surface 11A side of the multilayered piezoelectric body 11.

  FIG. 6 is a diagram for explaining the electrode patterns of each single-layer piezoelectric body 111. 6A is a diagram showing the electrode patterns on the front and back surfaces of each single-layer piezoelectric body 111, and FIG. 6B is a diagram showing the polarization directions of each single-layer piezoelectric body 111 in the laminated piezoelectric body 11. is there.

As shown in FIG. 6, the applied electrode pattern 16 is formed on the front surface 111aA of the first layer piezoelectric body 111a, the back surface 111bB of the second layer piezoelectric body 111a, and the front surface 111cA of the third layer piezoelectric body 111c. It is divided into two phases (A phase and B phase) along the direction.
In each phase, electrode patterns 17 are arranged so that they are alternately polarized every ½ wavelength, and an interval of ¼ wavelength is provided between the A phase and the B phase.

  The back surface 111aB of the first layer piezoelectric body 111a, the front surface 111bA of the second layer piezoelectric body 111b, and the back surface 111cB of the third layer piezoelectric body 111c are not divided electrode patterns 16 but two drive signal phases (A phase, A common electrode pattern 19 is formed as a B-phase common electrode.

  The back surface 111aB of the first layer piezoelectric body 111a and the front surface 111bA of the second layer piezoelectric body 111b are bonded together, and the back surface 111bB of the second layer piezoelectric body 111b and the surface 111cA of the third layer piezoelectric body 111c are bonded together. A laminated piezoelectric body 11 is formed.

The surface 111aA of the first layer piezoelectric body 111a becomes the surface 11A as the whole laminated piezoelectric body 11, and the back surface 111cB of the third layer piezoelectric body 111c becomes the back surface 11B as the whole laminated piezoelectric body 11.
As shown in FIGS. 5A and 5B, a flexible printed circuit board (FPC) 14 is adhered to the surface 11A as the laminated piezoelectric body 11 with an adhesive 18 in order to transmit a drive signal. The adhesive 18 is applied so as to extend from the side surfaces of the elastic body 12 and the piezoelectric body 11 to the FPC 14 to reinforce the adhesive strength.
Further, the back surface 11B as the laminated piezoelectric body 11 is joined to the elastic body 12 by a room temperature curable adhesive.

  As shown in FIG. 6B, the polarization of each layer (the first layer piezoelectric body 111a, the second layer piezoelectric body 111b, and the third layer piezoelectric body 111c) The polarization direction from the back side to the front side is opposite to the polarization direction from the back side to the front side of the even layer.

That is, in the first layer piezoelectric body 111a in the region P shown in FIG. 6B, when the polarization direction is from the back surface 111aB side to the front surface 111aA side (this direction is defined as a positive direction), the second layer piezoelectric body 111b. Then, the polarization direction (− direction) is directed from the front surface 111bA to the back surface 111bB, and the polarization direction (+ direction) is directed from the back surface 111cB to the front surface 111cA in the third-layer piezoelectric body 111c. That is, the polarization direction becomes + − + along the thickness direction of the piezoelectric body.
Further, in the region Q adjacent to the region P, the polarization direction is opposite to that of the region P, and becomes − + − along the thickness direction of the piezoelectric body.

  In the electrode and polarization configuration as described above, the number of single-layer piezoelectric bodies 111 in the piezoelectric body 11 is an odd number. That is, since the polarization direction of the first layer is the same as the polarization direction of the final layer, the number of single-layer piezoelectric bodies 111 is an odd number.

  The electrode pattern on the back side of the odd layer and the electrode pattern on the front side of the even layer are the same electrode pattern, and the electrode pattern on the back side of the even layer and the electrode pattern on the front side of the odd layer are the same electrode pattern.

That is, the electrode patterns on the back surfaces 111aB and 111cB of the odd-numbered layers (the first-layer piezoelectric body 111a and the third-layer piezoelectric body 111c in this embodiment) and the surface 111bA of the even-numbered layer (the second-layer piezoelectric body 111b in this embodiment) are It will be the same.
In this embodiment, these surfaces are divided into two drive signal phases (A phase and B phase) along the circumferential direction, and in each phase, every half wavelength alternately as shown in the figure. The application electrode pattern 16 is arranged so that it is polarized and an interval of ¼ wavelength is left between the A phase and the B phase.

  Further, the electrode patterns of the front surfaces 111aA and 111cA of the odd-numbered layers (first layer piezoelectric body 111a and third-layer piezoelectric body 111c in this embodiment) and the back surface 111bB of even-numbered layers (second layer piezoelectric body 111b in this embodiment) are It will be the same. In the present embodiment, not the divided application electrode pattern 16 but a common electrode pattern 19 of two drive signal phases (A phase and B phase) is formed.

In this embodiment, for simplicity of explanation, three layers are used as an example. However, if the number of layers is five, seven, nine,.
Further, although the wave number of the traveling wave has been described as four waves, any wave number such as five waves, six waves, seven waves, etc. may be used.

Here, as shown in FIGS. 4A, 4C, and 5, the single-layer piezoelectric body 111 (the first-layer piezoelectric body 111a, the second-layer piezoelectric body 111b, and the third-layer piezoelectric body 111c) It has an annular shape. The outer diameters of the first layer piezoelectric body 111a, the second layer piezoelectric body 111b, and the third layer piezoelectric body 111c become smaller in order.
That is, as shown in FIG. 4C, when the outer diameter ra of the first layer piezoelectric body 111a, the outer diameter rb of the second layer piezoelectric body 111b, and the outer diameter rc of the third layer piezoelectric body 111c, ra <rb <Rc. In this embodiment, the inner diameter is the same.

Therefore, as shown in FIGS. 4C and 5, when viewed as the laminated piezoelectric body 11, the outer diameter side in the cross-sectional view is stepped. FIG. 7 is an enlarged view of the stepped portion of the laminated piezoelectric body 11. FIG. 7A shows a portion where a later-described common conduction portion 18a is provided, and FIG. 7B shows a portion where a later-described application conduction portion 18b is provided.
When viewed from the surface 11A side of the first layer piezoelectric body 111a, the outer peripheral side of the surface 11A of the second layer piezoelectric body 111b becomes an exposed portion 40b exposed without overlapping the first layer piezoelectric body 111a. ing. Further, the outer peripheral side of the third layer piezoelectric body 111c is an exposed portion 40c exposed without overlapping the second layer piezoelectric body 111b.

  Further, as shown in FIGS. 4B, 4C, and 7, the electrode patterns 16, 17, and 19 are formed apart from the outer edge and the inner edge of the ring. A part of the space between the outer edge of the ring and the electrode patterns 16, 17, 19 is the exposed portions 40 b, 40 c described above.

  In the present embodiment, extending portions 16a, 17a, 19a extending from the respective electrode patterns 16, 17, 19 to the outer edge are formed in the separated portions (exposed portions 40b, 40c).

  7A, the electrode pattern 17 on the surface 111aA of the first layer piezoelectric body 111a, the extending portion 17a of the first layer piezoelectric body 111a, the side surface 111as of the first layer piezoelectric body 111a, The extending portion 19a (exposed portion 40b) of the surface 111bA of the second layer piezoelectric body 111b, the side surface 111bs of the second layer piezoelectric body 111b, and the extending portion 17a (exposed portion 40c) of the surface 111cA of the third layer piezoelectric body 111c. The common conductive portion 18 a extends so as to connect the side surface 111 cs of the third layer piezoelectric body 111 c and the common electrode pattern 19. In addition, the common conduction | electrical_connection part 18a is formed by apply | coating a conductive paint, for example.

Here, the extending portion 19a of the surface 111bA of the second layer piezoelectric body 111b is connected to the common electrode pattern 19 of the surface 111bA of the second layer piezoelectric body 111b and the common electrode pattern 19 of the back surface 111bB of the first layer piezoelectric body 111a. Is done.
The extending portion 17a of the surface 111cA of the third layer piezoelectric body 111c is connected to the electrode pattern 17 of the third layer piezoelectric body 111c and the electrode pattern 17 of the second layer piezoelectric body 111b.

  That is, the electrode pattern 17 on the front surface 111aA of the first layer piezoelectric body 111a, the common electrode pattern 19 on the back surface 111aB of the first layer piezoelectric body 111a, the common electrode pattern 19 on the surface 111bA of the second layer piezoelectric body 111b, The electrode pattern 17 on the back surface 111bB of the two-layer piezoelectric body 111b, the electrode pattern 17 on the front surface 111cA of the third-layer piezoelectric body 111c, and the common electrode pattern 19 on the back surface 111cB of the third-layer piezoelectric body 111c are common conducting portions 18a. Connected by.

  7B, the applied electrode pattern 16 on the surface 111aA of the first layer piezoelectric body 111a, the extending portion 16a of the first layer piezoelectric body 111a, the side surface 111as of the first layer piezoelectric body 111a, The exposed portion 40b of the surface 111bA of the second layer piezoelectric body 111b, the side surface 111bs of the second layer piezoelectric body 111b, the extending portion 16a of the surface 111cA of the third layer piezoelectric body 111c, and the applied electrode pattern 16 are connected. The application conduction portion 18b extends.

Here, the applied conducting portion 18b provided on the exposed portion 40b of the surface 111bA of the second layer piezoelectric body 111b is composed of the common electrode pattern 19 on the surface 111bA of the second layer piezoelectric body 111b and the back surface 111bB of the first layer piezoelectric body 111a. The common electrode pattern 19 is not connected.
On the other hand, the extending portion 16a of the surface 111cA of the third layer piezoelectric body 111c is connected to the application electrode pattern 16 of the third layer piezoelectric body 111c and the application electrode pattern 16 of the second layer piezoelectric body 111b.

  That is, the applied electrode pattern 16 on the front surface 111aA of the first layer piezoelectric body 111a, the applied electrode pattern 16 on the back surface 111bB of the second layer piezoelectric body 111b, the applied electrode pattern 16 on the surface 111cA of the third layer piezoelectric body 111c, Are connected by the application conduction part 18b.

  In this embodiment, the electrode patterns 16 and 19 of each layer are conducted on the outer peripheral side. However, a step shape may be formed on the inner peripheral side and the conduction may be conducted on the inner peripheral side. good.

FIG. 8 shows the expansion and contraction of the piezoelectric body 11 due to the applied voltage. When the drive signal is applied to +, the A-phase and B-phase electrodes are alternately extended and contracted as shown in FIG. That is, the region P is extended and the region Q is reduced.
On the other hand, when the drive signal is applied to-, contrary to the above, each electrode is alternately extended and reduced as shown in FIG. 8B. That is, the area P is reduced and the area Q is distracted.
Thus, in the configuration of the present embodiment, the same behavior as that of the conventional single-layer piezoelectric body 11 is exhibited in the applied voltage and the expansion / contraction direction.

As described above, according to the present embodiment, the single-layer piezoelectric bodies 111 constituting the multilayered piezoelectric body 11 are stacked stepwise. Further, the surface of the step portion is exposed, and the exposed portions 40b and 40c are provided with extending portions 16a, 17a, and 19a that are conductively extended from the electrode patterns formed on the front and back surfaces of the single-layer piezoelectric bodies 111, respectively. It has been.
By applying a conductive paint to the exposed portions of the extending portions 16a, 17a, 19a, conduction between the laminated piezoelectric bodies can be easily and reliably achieved.

Further, the magnitude of expansion / contraction (deformation) in the piezoelectric body varies depending on the strength of the electric field generated inside the piezoelectric body. That is, if the applied voltage is the same, the thinner the piezoelectric body, the stronger the electric field.
Therefore, it is better that the piezoelectric body is thin. However, if the single-layer piezoelectric body is thin, the strength is insufficient. However, according to the present embodiment, the strength can be ensured by stacking even if the thickness of the single-layer piezoelectric body is reduced.

  Since each single-layer piezoelectric body can be made thin, a large amount of deformation can be obtained without increasing the applied voltage so much. That is, a practical amount of deformation can be ensured without using a booster circuit or the like.

  Furthermore, the single-layer piezoelectric bodies 111 having the same electrode pattern are alternately arranged in different directions during lamination. That is, the laminated piezoelectric material 11 is formed by the single-layer piezoelectric material 111 having the same electrode pattern without using the single-layer piezoelectric material having different electrode patterns. For this reason, it is possible to reduce costs, simplify the manufacturing process, reduce operational errors, and improve yield and quality of piezoelectric characteristics.

  According to this embodiment, since the single-layer piezoelectric body 111 is laminated and each layer is made conductive by the conducting portion 18a, it is possible to simultaneously polarize all the single-layer piezoelectric bodies 111 with one applied voltage.

  As described above, according to the present embodiment, when the vibration wave motor 1 is assembled, the drive voltage can be lowered as compared with the conventional case, and the performance of the vibration wave motor 1 such as drive efficiency and generated torque can be improved. .

  This embodiment has a great effect on driving performance of the small-diameter type traveling wave type vibration wave motor 1 in which the driving voltage increases. In particular, when the outer diameter is 25 mm or less, the effect of this embodiment is remarkable.

Further, in order to obtain a wavelength, the small-diameter type traveling wave type vibration wave motor 1 needs to reduce the number of waves to 4 waves and 5 waves, but if the number of waves is reduced, the number of electrode patterns of the A phase and the B phase is reduced. Less.
In the case of four waves in the present embodiment, the number of electrode patterns of A phase (or B phase) is 4, and in the case of five waves, the number of electrode patterns of A phase (or B phase) is 5, but the electrodes of each phase When the number of patterns is small, bending vibration is difficult to be excited.

  Therefore, as in the present embodiment, each piezoelectric layer needs to be polarized so that piezoelectric characteristics can be obtained. In the present invention, the effect is particularly obtained when the number of traveling waves is four or five.

(Second Embodiment)
FIG. 9 is a diagram illustrating a piezoelectric body 11 ′ according to the second embodiment of the present invention, and corresponds to FIG. 4 of the first embodiment. The same parts as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.
FIG. 9A is a part of a side view of the piezoelectric body 11 ′ of the second embodiment. FIG. 9B is a view showing the surface 11A of the piezoelectric body 11 ′, and FIG. 9A is a view seen from the aa direction of FIG. 9B. FIG.9 (c) is cc sectional drawing of (b). FIG. 9D shows the back surface 11B of the piezoelectric body 11 ′. Furthermore, FIG.9 (e) is an enlarged view of the part enclosed with the dotted-line circle of (b).

In the first embodiment, the exposed portions 40b and 40c are formed by laminating the single-layer piezoelectric bodies 111 having different outer diameters so that the outer peripheral side is stepped. In the second embodiment, a notch 50 is provided in the piezoelectric body 11 ′, and the exposed portions 40 b and 40 c are provided by forming stepped portions by shifting the notch 50 in the circumferential direction.
That is, the semicircular first notch 50 is provided on the outer peripheral portion of the electrode pattern of the single-layer piezoelectric body 111, and the extending portions 16a, 17a, 19a are extended from the electrode patterns 16, 17, 19 there.

  When laminating the single-layer piezoelectric body 111, the first notch 50 is shifted slightly in the circumferential direction in each layer. At this time, the extending portions 16a, 17a, and 19a of the second layer piezoelectric body 111b and the third layer piezoelectric body 111c are made visible from the first cutout portion 50 of the first layer piezoelectric body 111a. That is, the extension portions 16a, 17a, and 19a of the second layer piezoelectric body 111b and the third layer piezoelectric body 111c are shifted so as to be exposed inside the first notch 50 of the first layer piezoelectric body 111a.

In order to shift in this way, in this embodiment, a reference cutout (second cutout 51) is provided in each layer. The distance between the second notch 51 and the first notch is different for each layer.
The distance between the second cutout portion 51 and the first cutout portion 50 in the second layer piezoelectric body 111b is larger than the distance between the second cutout portion 51 and the first cutout portion 50 in the first layer piezoelectric body 111a. The distance between the second notch 51 and the first notch 50 in the third-layer piezoelectric body 111c is larger than that.

When the single-layer piezoelectric body 111 is laminated, if the positions of the second cutout portions 51 are made to coincide in all layers in the thickness direction, the first cutout portion 50 of the first-layer piezoelectric body 111a The extending portions 16a, 17a, and 19a provided on the surfaces of the two-layer piezoelectric body 111b and the third-layer piezoelectric body 111c are shifted so as to be visible, and stepped portions are formed.
Also in the present embodiment, by applying a conductive paint to the stepped portion of the first notch 50, the electrodes of the single-layer piezoelectric body 111 can be made conductive as in the first embodiment.

(Third embodiment)
FIG. 10 is a diagram illustrating a lens barrel 200 according to the third embodiment of the present invention. The present invention can be configured not only in the piezoelectric body 11 of the small-diameter type vibration wave motor 1 of the first embodiment but also in the piezoelectric body 11 of the large-diameter ring-type vibration wave motor 210. The same effect as in the first embodiment can be obtained.

First, the configuration of the vibration wave motor 210 will be described.
The vibrator 211 includes a piezoelectric body 11 and an elastic body 214 joined with the piezoelectric body 11. The traveling wave is generated in the vibrator 211. In the present embodiment, the traveling wave is described as 9 traveling waves as an example.
The elastic body 214 is made of a metal material having a high resonance sharpness and has an annular shape. A groove is cut on the opposite surface to which the piezoelectric body 11 is bonded, and the surface of the portion where the groove is not provided becomes the driving surface 216a and is brought into pressure contact with the moving element 220. The surface of the driving surface 216a of the elastic body 214 is provided with a lubricating coating film for ensuring driving performance and improving durability.

  The piezoelectric body 11 is divided into two phases (A phase and B phase) along the circumferential direction, and in each phase, elements with alternating polarization for each half wavelength are arranged. An interval of 1/4 wavelength is provided between the A phase and the B phase.

A non-woven fabric 252 and a pressure member 250 are disposed under the piezoelectric body 11.
The nonwoven fabric 252 is an example of felt, and is disposed under the piezoelectric body 11 so as not to transmit the vibration of the vibrator 211 to the pressure member 250.

  The pressure member 250 is disposed under a pressure plate (not shown) and generates pressure. In the present embodiment, a coil spring or a wave spring may be used instead of a disc spring in which the pressure member 250 is a disc spring. The pressure member 250 is held by the pressing ring 251 being fixed to the fixing member 223.

The mover 220 is made of a light metal such as aluminum, and a sliding material for improving wear resistance is provided on the surface of the sliding surface.
On the moving element 220, a vibration absorbing member 243 such as rubber is arranged to absorb the vertical vibration of the moving element 220, and an output transmission member 242 is arranged thereon.

The output transmission member 242 regulates the pressurization direction and the radial direction by a bearing 253 provided on the fixed member 223, thereby regulating the pressurization direction and the radial direction of the moving element 220. .
The output transmission member 242 has a protrusion 241 from which a fork connected to the cam ring 315 is engaged, and the cam ring 315 is rotated with the rotation of the output transmission member 242.

In the cam ring 315, a key groove 317 is cut obliquely in the cam ring 315, and a fixing pin 318 provided in the AF ring 319 is engaged with the key groove 317 so that the cam ring 315 is rotationally driven. As a result, the AF ring 319 is driven in the straight direction in the optical axis direction, and can be stopped at a desired position.
In the fixing member 223, the pressing ring 251 is attached with a screw, and by attaching this, the output transmission member 242, the moving element 220, the vibrator 211, and the pressing member 250 can be configured as one motor unit.

The piezoelectric body 213 of the third embodiment is also a laminated piezoelectric body similar to the piezoelectric body 11 of the first embodiment.
That is, a single-layer piezoelectric body is laminated by a plurality of layers (three layers in this embodiment). The first-layer piezoelectric body, the second-layer piezoelectric body, and the third-layer piezoelectric body are arranged in this order from the side opposite to the adhesive surface of the laminated piezoelectric body with the elastic body.

And the electrode is arrange | positioned at the surface side of the 1st layer piezoelectric material, and it is divided into the phase (A phase, B phase) of two drive signals along the circumferential direction. In each phase, the electrodes are arranged so that they are alternately polarized every ½ wavelength, and an interval of ¼ wavelength is left between the A phase and the B phase.
On the back surface of the first layer piezoelectric body, not a divided electrode pattern but a common electrode pattern of two drive signal phases (A phase and B phase) is formed.

On the surface of the second layer piezoelectric body, not a divided electrode pattern but a common electrode pattern of two drive signal phases (A phase and B phase) is formed. The surface of the second layer and the back surface B of the first layer are bonded together.
An electrode is disposed on the back surface side of the second layer piezoelectric body, which is divided into two drive signal phases (A phase and B phase) along the circumferential direction. In each phase, the electrodes 16 are arranged so that they are alternately polarized every ½ wavelength, and an interval of ¼ wavelength is left between the A phase and the B phase.

Electrodes are arranged on the surface of the third layer piezoelectric body, which is divided into two drive signal phases (A phase and B phase) along the circumferential direction. In each phase, the electrodes are arranged so that they are alternately polarized every ½ wavelength, and an interval of ¼ wavelength is left between the A phase and the B phase. The back surface of the second layer piezoelectric body and the front surface of the third layer piezoelectric body are bonded together.
On the back surface of the third layer piezoelectric body, not a divided electrode pattern, but a common electrode pattern of two drive signal phases (A phase and B phase) is formed.
Also in the third embodiment, the single-layer piezoelectric bodies constituting the multilayered piezoelectric body are laminated stepwise. And the surface of the step portion is exposed, and a conductive portion is provided in the exposed portion.
As described above, the third embodiment has the same effect as that of the first embodiment.

  1: vibration wave motor, 10: vibrator, 11: piezoelectric body (laminated piezoelectric body), 12: elastic body, 12a: driving surface, 12f: bonding surface, 16: applied electrode pattern, 16a: extending portion, 17: electrode Pattern, 17a: Extension part, 18a: Common conduction part, 18b: Applied conduction part, 19: Common electrode pattern, 20: Mover, 50: First notch part, 51: Second notch part, 110: Lens mirror 111, single layer piezoelectric body, 111a: first layer piezoelectric body, 111b: second layer piezoelectric body, 111c: third layer piezoelectric body, 200: lens barrel, 210: vibration wave motor, 211: vibrator, 213: Piezoelectric body, 214: Elastic body, 218a: Driving surface, 220: Mover

Claims (6)

A laminate of electromechanical transducers in which vibration is generated by a drive signal;
An elastic body having a bonding surface to be bonded to the laminate and a driving surface that is provided on the opposite side of the bonding surface and generates a progressive vibration wave by the vibration;
A relative motion member that is in pressure contact with the drive surface and driven by the vibration wave,
In the laminate, a plurality of monolayers of the electromechanical conversion element are laminated in the thickness direction of the elastic body,
When the laminate is viewed from one side parallel to the joint surface, there is an exposed portion where the surface is exposed without overlapping the front monolayer in the rear monolayer, and the exposed portion Is continuous in stages,
That a continuous portion between the monolayers is formed in the continuous exposed portion;
Vibration wave motor characterized by The vibration wave motor according to claim 1,
The monolayer has an annular shape, and the exposed portion is formed on an outer peripheral side or an inner peripheral side of the annular shape;
Vibration wave motor characterized by In the vibration wave motor according to claim 1 or 2,
The single-layer body has different outer diameters or inner-periphery diameters, and the exposed portions are formed stepwise by laminating the single-layer bodies having different diameters.
Vibration wave motor characterized by In the vibration wave motor according to claim 1 or 2,
Each of the single-layer bodies is provided with a first notch, and when the single-layer bodies are stacked, the positions of the first notches are shifted from each other, so that the exposed portion is stepped. Being formed,
Vibration wave motor characterized by The vibration wave motor according to claim 4,
The single layer body is provided with a second cutout portion different from the first cutout portion,
The distance between the first notch and the second notch varies depending on the monolayer,
When laminating the single-layer body, the exposed portions are stepped at the edge of the first notch by arranging the single-layer bodies so that the second notch portions are aligned in the thickness direction. Formed into,
Vibration wave motor characterized by   A lens barrel provided with the vibration wave motor according to claim 1.

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