JP2010104156A - Ultrasonic motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ultrasonic motor that suppresses variations in performance and is manufacturable by a simplified process without requiring an abutting/positioning step between an elastic body and a piezoelectric body by integrally constituting the elastic body with the piezoelectric body. <P>SOLUTION: The ultrasonic motor is equipped with a piezoelectric body part 4b having: an active layer which adopts a multilayer structure comprising a plurality of plate-shaped piezoelectric elements and is piezoelectrically activated by polarization of an electrode film provided on each plate-shaped piezoelectric element; and an inactive layer which is provided so as to sandwitch the active layer in the height direction of the piezoelectric body part 4b. The active layer has a prescribed inclination angle with respect to a face forming a right angle with the height direction of the piezoelectric body part 4b. A face facing a driver of the inactive layer and a face facing a frequency adjusting part of the inactive layer, are parallel to a face perpendicular to the height direction of the piezoelectric body part 4b while the faces respectively form a right angle with respect to the side face of the piezoelectric body part 4b. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an ultrasonic motor using an ultrasonic transducer that uses an electromechanical transducer such as a piezoelectric element as a drive source.

  In recent years, ultrasonic motors have attracted attention as new motors that replace electromagnetic motors. Ultrasonic motors have the following advantages over conventional electromagnetic motors.

(Advantage 1) High torque can be obtained without gears.

(Advantage 2) There is a holding force when the electricity is OFF.

(Advantage 3) High resolution.

(Advantage 4) It is rich in silence.

(Advantage 5) Magnetic noise is not generated and is not affected by noise.

  By the way, as a technique related to such an ultrasonic motor, for example, Patent Document 1 discloses the following technique.

  That is, in Patent Document 1, the vibrator is sandwiched so as to occupy a part in the height direction of the vibrator and has a predetermined inclination with respect to the height direction of the vibrator. A longitudinal and torsional vibration type superstructure having one or a plurality of plate-like piezoelectric elements that are arranged in the thickness direction and each provided with a divided electrode, and a driven body that is pressed against the vibrator. A sonic motor is disclosed.

In other words, in the ultrasonic motor disclosed in Patent Document 1, one or a plurality of plate-like piezoelectric elements that are polarized in the thickness direction and each have a divided electrode are arranged so as to have a predetermined inclination and are piezoelectric. The piezoelectric body is sandwiched by the elastic body so as to be parallel to the inclination of the elastic body and occupy a part in the height direction of the vibrator. That is, the ultrasonic motor disclosed in Patent Document 1 is configured to be assembled by applying an elastic body and a piezoelectric body to each other on inclined planes.
JP-A-9-117168

  Of course, it is very difficult to perform assembly work while accurately positioning the inclined planes to perform positioning. That is, ideal contact cannot be achieved unless the end face of the elastic body and the end face of the piezoelectric body are positioned with high accuracy. Furthermore, the planar accuracy of each of the end face of the elastic body and the end face of the piezoelectric body needs to be good. When the planar accuracy is poor, the area of the contact portion changes, which hinders vibration transmission. This leads to variations in the performance of each ultrasonic motor.

  The present invention has been made in view of the above circumstances, and has been simplified by not requiring an abutment / positioning step between the elastic body and the piezoelectric body by integrally configuring the elastic body and the piezoelectric body. An object of the present invention is to provide an ultrasonic motor that can be manufactured by a process and that can suppress variations in performance.

In order to achieve the above object, an ultrasonic motor according to an aspect of the present invention includes:
Utilizing the stretching vibration of the piezoelectric body, longitudinal vibration and torsional vibration are simultaneously excited in the vibrating body including the piezoelectric body, and elliptical motion is excited in the driver provided on the end face of the vibrating body, An ultrasonic motor that rotates a rotor by a driver;
The vibrator is
An active layer having a multilayer structure composed of a plurality of plate-like piezoelectric elements and having an electrode film provided on the plate-like piezoelectric element polarized and piezoelectrically activated, and the active layer in the height direction of the piezoelectric body A piezoelectric body comprising an inactive layer provided so as to sandwich the shaft, and a through hole for inserting a shaft for positioning the center of the rotor and the driver;
A frequency adjusting unit for adjusting the frequency of the longitudinal vibration and the torsional vibration;
Comprising
The active layer has a predetermined inclination angle with respect to a surface perpendicular to the height direction of the piezoelectric body, and a surface of the inactive layer that faces the driver and the surface that faces the frequency adjusting unit. Is characterized by being parallel to a plane perpendicular to the height direction of the piezoelectric body and perpendicular to a side surface of the piezoelectric body.

  According to the present invention, by configuring the elastic body and the piezoelectric body integrally, it can be manufactured by a simplified process without requiring an abutment / positioning process between the elastic body and the piezoelectric body, and in terms of performance. An ultrasonic motor capable of suppressing variations can be provided.

[First Embodiment]
Hereinafter, an ultrasonic motor according to a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram illustrating a configuration example of the ultrasonic motor according to the first embodiment.

  The ultrasonic motor according to the first embodiment is a longitudinal / torsional vibration type ultrasonic wave including a pressing portion 2, a driving element 3, a vibrating body portion 4, a central shaft 6, and a rotor 8. It is a motor.

  The pressing portion 2 includes a nut 2a and a spring 2c. The vibrating body portion 4 includes a piezoelectric body portion 4b and a frequency adjusting portion 4c.

  Here, a through-hole is provided in the central portion of the rotor 8, the driver 3, and the piezoelectric body portion 4b. The central shaft 6 is inserted into the through hole. The central shaft 6 is fixed to a longitudinal vibration node of the frequency adjusting unit 4c with, for example, a screw. Further, the central shaft 6 has a function of positioning the center of the rotor 8 and the pressing portion 2.

  The pressing portion 2 is disposed on the upper end surface of the rotor 8. The pressing portion 2 is a pressing force that pressurizes the rotor 8 by rotating the nut 2a and bending the spring 2c by a screw (not shown) provided on the central shaft 6. Produce.

  The rotor 8 is pressed by an appropriate force so as to be rotatable in the central axis direction by the vibrating body portion 4 through the driver 3 while being pressed by the pressing portion 2. The driver element 3 is provided by being bonded and fixed to the upper end surface of the piezoelectric body portion 4b.

  The frequency adjusting unit 4c is a member that is fixed to the lower end surface of the piezoelectric body unit 4b with an adhesive or the like, and adjusts the resonance frequency difference between longitudinal vibration and torsional vibration. The frequency adjusting portion 4c and the piezoelectric body portion 4b are bonded and fixed so as to be integrated in the insertion direction of the central shaft 6.

  Hereinafter, the vibrating body part 4 which is one of the characteristic parts of the ultrasonic motor according to the first embodiment will be described in detail.

  The piezoelectric body portion 4b is a member including a structure in which plate-like piezoelectric elements are stacked. The material of the plate-like piezoelectric element constituting the piezoelectric body portion 4b is, for example, a lead zirconate titanate (so-called PZT) piezoelectric ceramic element having a thickness of 100 μm.

  The plate-like piezoelectric element is provided with a plurality of internal electrodes (electrode films) on one surface, two of the internal electrodes are drive electrodes, and the remaining internal electrodes are vibration detection electrodes. is there. As a material of these internal electrodes, for example, a silver palladium alloy having a thickness of 4 μm can be mentioned.

  FIG. 2A is a diagram illustrating a configuration example of the piezoelectric body portion 4b. As shown in FIG. 2A, the piezoelectric body portion 4b includes an active layer 11 that is a region in which the internal electrode is piezoelectrically polarized, and an inactive layer 13 that is a region that is not polarized. Although the details of the manufacturing method will be described later, as shown in FIG. 2A, the active layer 11 is a layer formed by laminating plate-like piezoelectric elements 11a activated by polarization of the internal electrodes, and the inactive layer 13 is inactive. This is a layer made of an active (unpolarized) member 13a. Here, the inactive member 13a may be formed, for example, by laminating the plate-like piezoelectric elements 11a and not causing the internal electrodes of the plate-like piezoelectric elements 11a to be piezoelectrically polarized.

  The inert layer 13 corresponds to a so-called “elastic body” in a conventional ultrasonic motor. In the ultrasonic motor according to the first embodiment, the “elastic body” in the conventional ultrasonic motor (the inert layer 13 of the piezoelectric body portion 4b in the ultrasonic motor according to the first embodiment) and the conventional ultrasonic wave are used. The “piezoelectric body” in the motor (the active layer 11 of the piezoelectric body portion 4b in the ultrasonic motor according to the first embodiment) is integrally configured.

  More specifically, the active layer 11 is configured by alternately laminating plate-like piezoelectric elements 11a provided with + -pole internal electrodes and plate-like piezoelectric elements 11a provided with −-pole internal electrodes. ing. An adhesive may be used for such lamination, or an integral baking method may be used.

  FIG. 2B is a diagram illustrating an arrangement example of internal electrodes and external electrodes. As shown in FIG. 2B, a drive internal electrode 14A and a vibration detection internal electrode 14B are provided as internal electrodes. For each of the driving internal electrode 14A and the vibration detecting internal electrode 14B, a positive external electrode 15a and a negative external electrode 15b are provided as external electrodes with respect to the layer corresponding to the active layer 11. ing. Thus, the internal electrodes of the same pole and the same phase are electrically connected and short-circuited by the corresponding external electrodes.

  Then, by applying a high voltage between the positive electrode and the negative electrode in the plate-like piezoelectric element 11a corresponding to the region to be piezoelectrically activated, the internal electrode is polarized and piezoelectrically applied. Thus, the active layer 11 can be formed.

  By adopting the above-described configuration and applying a predetermined voltage to the active layer 11, longitudinal primary vibration and torsional secondary vibration are generated in the vibrating body portion 4. Due to the combined vibration of the longitudinal vibration and the torsional vibration, elliptical vibration is generated at the contact portion between the vibrating body portion 4 and the rotor 8. The rotor 8 is rotated by this elliptical vibration.

  Here, longitudinal vibration and torsion are caused by a dimensional ratio between the total length of the piezoelectric body portion 4b and the total length of the frequency adjustment portion 4c (in other words, the position of the groove that is the bonding portion between the piezoelectric body portion 4b and the frequency adjustment portion 4c). The resonance frequency difference of vibration changes. In addition, by making the contact pressure between the rotor 8 and the driver 3 appropriate, the resonance frequencies of the longitudinal vibration and the torsional vibration can be matched.

  Hereinafter, an example of a method for manufacturing the piezoelectric body portion 4b shown in FIGS. 1 to 2B will be described with reference to FIGS.

<< Production Method Example 1 >>
FIG. 3 is a diagram illustrating an example of a method for manufacturing the piezoelectric body portion 4b. In the example shown in FIG. 3, the plate-like piezoelectric element 11a is provided with a predetermined inclination angle θ from a plane perpendicular to the height direction (the direction of the central axis 100 shown in FIG. 3). Laminate in the thickness direction of 11a. Then, the upper and lower end surfaces of the plate-like piezoelectric element 11a are sandwiched between inert members 13a having upper and lower end surfaces parallel to the upper and lower end surfaces as shown in FIG. The inactive member 13 a is a member that forms the inactive layer 13. As shown in FIG. 3, the upper and lower end surfaces of the plate-like piezoelectric element 11a and the upper and lower end surfaces of the inactive member 13a are parallel to each other. And the piezoelectric body part 4b is cut out by cut | disconnecting the said laminated body in the area | region corresponding to the cutting area | region 17 shown in FIG.

  In other words, in the manufacturing method example 1, the plate-like piezoelectric element 11a having a shape in which the surface on which the electrode film as the internal electrode is formed and the outer surface form a right angle is formed from the surface perpendicular to the thickness direction. Lamination is performed in a thickness direction while shifting in a predetermined amount and a predetermined direction at a predetermined inclination angle. After being laminated in this way, an inert member 13a having a predetermined thickness is provided on the upper and lower surfaces. Thereafter, as described above, the laminated body is cut so as to cut out a region corresponding to the cutting region 17, so that the upper and lower end surfaces of the piezoelectric body portion 4b are formed so as to make a right angle with the outer surface. By such a process, the active layer 11 realizes the piezoelectric body portion 4b having a configuration in which the active layer 11 is provided with a predetermined inclination angle from the upper and lower end surfaces of the piezoelectric body portion 4b.

≪Production method example 2≫
FIG. 4 is a diagram illustrating an example of a method for manufacturing the piezoelectric body portion 4b. In the example shown in FIG. 4, the plate-like piezoelectric element 11a is provided with a predetermined inclination angle θ from a plane perpendicular to the height direction (the direction of the central axis 100 shown in FIG. 4). It is laminated in the thickness direction of 11a. And the piezoelectric body part 4b is cut out by cut | disconnecting the said laminated body in the cutting | disconnection area | region 17 shown in FIG.

  Thereafter, when the polarization treatment described above is performed, the internal electrode of the plate-like piezoelectric element 11a in the region to be the inactive layer 13 is not polarized. In other words, a high voltage is applied between the positive external electrode 15a and the negative external electrode 15b corresponding to the internal electrode of the plate-like piezoelectric element 11a in the region to be the active layer 11, and the piezoelectric layer is polarized. Make it. In this manner, the active layer 11 that is a polarization region and the inactive layer 13 that is a non-polarized region are provided.

  In other words, in manufacturing method example 2, the rectangular parallelepiped plate-shaped piezoelectric element 11a in which the surface on which the electrode film as the internal electrode is formed and the outer surface form a right angle is formed from the surface perpendicular to the thickness direction. Then, the layers are laminated in the thickness direction while shifting in a predetermined amount and in a predetermined direction at a predetermined inclination angle. After the lamination, the inert layer 13 is formed in order to provide the “elastic body” in the conventional ultrasonic motor (the inert layer 13 of the piezoelectric portion 4b in the ultrasonic motor according to the first embodiment). The plate-like piezoelectric element 11a to be laminated is further laminated, and the plate-like piezoelectric element 11a related to the lamination is not subjected to polarization treatment. Note that, as described above, the laminated body is cut so as to cut out a region corresponding to the cutting region 17, so that the upper and lower end surfaces of the piezoelectric body portion 4b are formed so as to make a right angle with the outer surface. In this way, it is possible to manufacture the piezoelectric body portion 4b having the same configuration as when the manufacturing method example 1 is adopted.

<Effects Specific to Manufacturing Method Example 1 and Manufacturing Method Example 2>
According to the manufacturing method example 1 and the manufacturing method example 2, the “elastic body” in the conventional ultrasonic motor (the inert layer 13 of the piezoelectric body portion 4b in the ultrasonic motor according to the first embodiment) and the conventional ultrasonic motor The “piezoelectric body” in the sonic motor (the active layer 11 of the piezoelectric body portion 4b in the ultrasonic motor according to the first embodiment) is integrally configured. Therefore, the number of assembling steps is greatly reduced, and the performance variation among the individual ultrasonic motors is greatly suppressed. Further, an “elastic body” in the conventional ultrasonic motor (inactive layer 13 of the piezoelectric body portion 4b in the ultrasonic motor according to the first embodiment) and a “piezoelectric body” in the conventional ultrasonic motor (the first first). Since positioning in the rotation direction with the internal electrode provided in the active layer 11b of the piezoelectric body portion 4b in the ultrasonic motor according to the embodiment is not required, the variation in performance is further reduced. That is, a low-cost ultrasonic motor with high performance and small performance variation is realized.

  In other words, by adopting a manufacturing method of cutting the outer shape after laminating the plate-like piezoelectric element in which the surface on which the internal electrode is formed and the outer surface form a right angle in the thickness direction at a predetermined inclination angle, The machining process for manufacturing the piezoelectric body portion 4b is a very simple process. Also in the step of laminating the plate-like piezoelectric elements 11a, it is possible to simply laminate the layers by positioning them based on the outer shape. Furthermore, since unnecessary regions are cut according to the state of the piezoelectric body portion 4b after lamination, a lower-cost ultrasonic motor can be provided.

<< Production Method Example 3 >>
FIG. 5 is a diagram illustrating an example of a method for manufacturing the piezoelectric body portion 4b. In the example shown in FIG. 5, a rectangular plate-like piezoelectric element 11 a in which the surface on which an electrode film as an internal electrode is formed and the outer surface thereof are perpendicular to each other is laminated in parallel with the thickness direction. Then, the upper and lower end surfaces of the plate-like piezoelectric element 11a are sandwiched between inert members 13a having upper and lower end surfaces parallel to the upper and lower end surfaces as shown in FIG. The inactive member 13 a is a member that forms the inactive layer 13.

  After that, by cutting a region corresponding to the cutting region 17 shown in FIG. 5, the quadrangular prism-shaped piezoelectric body portion 4b is cut out. That is, the plate-like piezoelectric element 11a is cut with respect to the upper and lower surfaces of the multilayer body so as to have a predetermined inclination angle with respect to the stacking direction, and the plane parallel to the stacking direction so that the upper and lower end surfaces and the outer surface are perpendicular Also cut off.

<< Production Method Example 4 >>
FIG. 6 is a diagram illustrating an example of a method for manufacturing the piezoelectric body portion 4b. In the example shown in FIG. 6, a plate-like piezoelectric element 11a in which a surface on which an electrode film as an internal electrode is formed and its outer surface form a right angle is laminated in parallel with the thickness direction. Then, the laminated body formed by laminating the plate-like piezoelectric elements 11a in this manner is cut so that the upper and lower end surfaces thereof have a predetermined inclination angle with respect to the laminating direction. That is, by cutting the region corresponding to the cutting region 17 shown in FIG. 6, the quadrangular prism-shaped piezoelectric body portion 4b is cut out.

  Thereafter, when the polarization treatment described above is performed, the internal electrode of the plate-like piezoelectric element 11a in the region to be the inactive layer 13 is not polarized. In other words, a high voltage is applied between the positive external electrode 15a and the negative external electrode 15b corresponding to the internal electrode of the plate-like piezoelectric element 11a in the region to be the active layer 11, and the piezoelectric layer is polarized. Make it. In this manner, the active layer 11 that is a polarization region and the inactive layer 13 that is a non-polarized region are provided. In this way, the upper and lower end surfaces form a right angle with the outer shape surface, and the active layer 11 sandwiched between the inactive layers 13 is formed with the piezoelectric body portion 4b having a predetermined inclination angle from the upper and lower end surfaces.

<Effects Specific to Manufacturing Method Example 3 and Manufacturing Method Example 4>
According to Manufacturing Method Example 3 and Manufacturing Method Example 4, in addition to the effects specific to Manufacturing Method Example 1 and Manufacturing Method Example 2, the following effects are achieved. That is, in the laminating process of the plate-like piezoelectric element 11a, the laminating direction is simply a direction parallel to the thickness direction, so that the laminating process is simpler.

<< Production Method Example 5 >>
FIG. 7A is a diagram illustrating an example of a method for manufacturing the piezoelectric body portion 4b. As shown in FIG. 7A, a disk-shaped piezoelectric element 11b having a circular surface on which an electrode film is formed may be used as the piezoelectric element constituting the piezoelectric body portion 4b. Also in this case, as in Manufacturing Method Example 1 and Manufacturing Method Example 3, the disk-shaped piezoelectric elements 11b are stacked in a direction parallel to the thickness direction to form the active layer 11, and the upper and lower surfaces of the active layer 11 are formed. Is sandwiched between inert members 13a having upper and lower end surfaces parallel to the upper and lower end surfaces as shown in FIG. 7A. The inactive member 13 a is a member that forms the inactive layer 13.

  Thereafter, the inert member 13a is cut at a predetermined inclination angle, so that the electrode film forming surface of the disk-shaped piezoelectric element 11b constituting the active layer 11 and the upper and lower end surfaces of the piezoelectric body portion 4b have a predetermined inclination angle. The piezoelectric body portion 4b having the structure is formed.

  Of course, the manufacturing methods of manufacturing method example 2 and manufacturing method example 4 may be applied to this manufacturing method example 5. That is, after laminating the disk-shaped piezoelectric element 11b over the entire height direction, the piezoelectric body portion 4b is cut by cutting the piezoelectric body portion 4b at a predetermined inclination angle with respect to the laminating direction. At this time, the upper and lower end surfaces related to the cutting are parallel to each other. And when performing the polarization process mentioned above, the internal electrode of the plate-shaped piezoelectric element 11a of the area | region used as the inactive layer 13 is not polarized.

  As shown in FIG. 7B, the disk-shaped piezoelectric element 11b is provided with a drive internal electrode 14A and a vibration detection internal electrode 14B as internal electrodes. A high voltage is applied between the positive external electrode 15a and the negative external electrode 15b corresponding to the internal electrode of the plate-like piezoelectric element 11a in the region to be the active layer 11, and the piezoelectric layer is polarized. Make it. In this manner, the active layer 11 that is a polarization region and the inactive layer 13 that is a non-polarized region are provided.

<Effects Specific to Manufacturing Method Example 5>
As described above, by using the disk-shaped piezoelectric element 11b, the piezoelectric body portion 4b has a cylindrical shape. The cylindrical shape is a shape that easily causes torsional vibration. Furthermore, by adopting the cylindrical shape, the symmetry of the piezoelectric body portion 4b is enhanced, and the symmetry of the entire ultrasonic motor is also enhanced. For this reason, according to this manufacturing method example 5, a more efficient ultrasonic motor is realized.

  As described above, according to the first embodiment, the abutting / positioning process between the elastic body and the piezoelectric body, which has been conventionally required in the manufacturing process of the ultrasonic motor, is not required and is greatly simplified. Therefore, it is possible to provide an ultrasonic motor that can be manufactured in the same manufacturing process and can greatly suppress variation in performance.

[Second Embodiment]
Hereinafter, an ultrasonic motor according to a second embodiment of the present invention will be described. In order to avoid duplication of explanation, differences from the ultrasonic motor according to the first embodiment will be described. FIG. 8 is a diagram illustrating a configuration example of the ultrasonic motor according to the second embodiment.

  In the ultrasonic motor according to the second embodiment, instead of the central shaft 6 of the ultrasonic motor according to the first embodiment, a mandrel 6 'is provided integrally with the frequency adjusting unit 4c as shown in FIG. Yes. The mandrel 6 'is threaded from its tip to the center to provide a thread. The piezoelectric body portion 4b is inserted into the mandrel 6 'and is pressed by the nut 9 from above. In this way, the piezoelectric body portion 4b and the frequency adjustment portion 4c are firmly fixed. The driver 3 is bonded to the upper surface of the nut 9 with the mandrel 6 'as a reference, and the rotor 8 and the pressing portion 2 are inserted into the mandrel 6' in this order.

  As described above, according to the second embodiment, it is possible to provide an ultrasonic motor that has the following effects in addition to the same effects as the ultrasonic motor according to the first embodiment. That is, in the ultrasonic motor according to the second embodiment, since the frequency adjustment unit 4c and the piezoelectric body unit 4b are in contact with each other by the flat portions, a more stable ultrasonic motor is realized. Moreover, since the frequency adjustment part 4c and the piezoelectric body part 4b are firmly fixed by the screw tightening action using the thread provided on the mandrel 6 'described above, a process for adhering them is necessary. Disappear. Therefore, stability in temperature characteristics and the like is further improved as an ultrasonic motor.

[Third Embodiment]
Hereinafter, an ultrasonic motor according to a third embodiment of the present invention will be described. In order to avoid duplication of explanation, differences from the ultrasonic motor according to the first embodiment will be described. FIG. 9 is a diagram illustrating a configuration example of the ultrasonic motor according to the third embodiment.

  In the third embodiment, all the parts of the vibrating body part 4 are integrally formed by the following process. That is, in the ultrasonic motor according to the third embodiment, as an inactive layer, in addition to the inactive layer 13 that sandwiches the active layer 11 as in the first embodiment, a frequency adjustment inactive layer that functions as a frequency adjustment unit. 13 'is formed.

  In other words, the frequency adjusting inactive layer 13 ′ is formed by processing the inactive layer 13 provided below the active layer 11 to provide a groove. Thereby, the whole vibrating body part 4 can be formed integrally.

  Note that the vibrating body portion 4 is provided with a through hole, and a central shaft 6 ″ having a flange 6 a at the end is inserted through the through hole. Further, as shown in FIG. 9, by adopting a configuration in which the central axis 6 ″ is inserted from the lower part of the vibrating body part 4, the central axis 6 ″ is removed from the upper part of the vibrating body part 4. Although not shown, a rotor, a pressing portion, and the like are arranged on the upper portion of the vibrating body portion 4 in the same manner as the ultrasonic motor according to the first embodiment.

  As described above, according to the third embodiment, it is possible to provide an ultrasonic motor having the following effects in addition to the same effects as the ultrasonic motor according to the first embodiment. That is, according to the ultrasonic motor according to the third embodiment, the step of providing the frequency adjusting unit (adhesion step) in the vibrating body unit 4 is not necessary, so that the ultrasonic wave having higher performance, less variation, and lower cost. A motor can be provided.

  The present invention has been described based on the first to third embodiments. However, the present invention is not limited to the above-described embodiments, and various modifications and applications can be made within the scope of the gist of the present invention. Of course, it is possible.

  Further, the above-described embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements. For example, even if some constituent requirements are deleted from all the constituent requirements shown in the embodiment, the problem described in the column of the problem to be solved by the invention can be solved, and the effect described in the column of the effect of the invention can be achieved. In the case of being obtained, a configuration from which this configuration requirement is deleted can also be extracted as an invention.

The figure which shows the example of 1 structure of the ultrasonic motor which concerns on 1st Embodiment of this invention. The figure which shows the example of 1 structure of a piezoelectric material part The figure which shows the example of arrangement | positioning of an internal electrode and an external electrode. The figure which shows an example of the manufacturing method of a piezoelectric material part. The figure which shows an example of the manufacturing method of a piezoelectric material part. The figure which shows an example of the manufacturing method of a piezoelectric material part. The figure which shows an example of the manufacturing method of a piezoelectric material part. The figure which shows an example of the manufacturing method of a piezoelectric material part. The figure which shows the example of arrangement | positioning of an internal electrode and an external electrode. The figure which shows the example of 1 structure of the ultrasonic motor which concerns on 2nd Embodiment of this invention. The figure which shows the example of 1 structure of the ultrasonic motor which concerns on 3rd Embodiment of this invention.

Explanation of symbols

    DESCRIPTION OF SYMBOLS 2 ... Press part, 3 ... Driver, 4 ... Vibration body part, 4b ... Piezoelectric body part, 4c ... Frequency adjustment part, 6 ... Center axis shaft, 6 '... Mandrel, 6a ... Flange, 6 "... Center axis, DESCRIPTION OF SYMBOLS 8 ... Rotor, 9 ... Nut, 11 ... Active layer, 11a ... Plate-shaped piezoelectric element, 11b ... Disc-shaped piezoelectric element, 13 ... Inactive layer, 13a ... Inactive member, 13 '... Frequency adjustment inactive layer, 14A ... Drive internal electrode, 14B ... vibration detection internal electrode, 15a, 15b ... external electrode, 15a ... external electrode, 15b ... external electrode.

Claims (4)

Utilizing the stretching vibration of the piezoelectric body, longitudinal vibration and torsional vibration are simultaneously excited in the vibrating body including the piezoelectric body, and elliptical motion is excited in the driver provided on the end face of the vibrating body, An ultrasonic motor that rotates a rotor by a driver;
The vibrator is
An active layer having a multilayer structure composed of a plurality of plate-like piezoelectric elements and having an electrode film provided on the plate-like piezoelectric element polarized and piezoelectrically activated, and the active layer in the height direction of the piezoelectric body A piezoelectric body comprising an inactive layer provided so as to sandwich the shaft, and a through hole for inserting a shaft for positioning the center of the rotor and the driver;
A frequency adjusting unit for adjusting the frequency of the longitudinal vibration and the torsional vibration;
Comprising
The active layer has a predetermined inclination angle with respect to a surface perpendicular to the height direction of the piezoelectric body, and a surface of the inactive layer that faces the driver and the surface that faces the frequency adjusting unit. Is an ultrasonic motor characterized by being parallel to a plane perpendicular to the height direction of the piezoelectric body and perpendicular to a side surface of the piezoelectric body. In the plate-like piezoelectric element, the electrode film forming surface and the side surface form a right angle,
The piezoelectric body is formed by cutting the laminated plate-shaped piezoelectric element so that the active layer has a predetermined inclination angle with respect to a plane perpendicular to the height direction of the piezoelectric body. The ultrasonic motor according to claim 1.   The ultrasonic motor according to claim 1, wherein the plate-like piezoelectric element has a disk shape.   The ultrasonic motor according to claim 1, wherein the frequency adjusting unit is formed by providing a groove in the inert layer.

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