JPH0993965A - Ultrasonic oscillator and ultrasonic motor using the ultrasonic oscillator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ultrasonic motor where the constitution can be simpli fied and also which can be driven at a low voltage. SOLUTION: Piezoelectric elements 3 and 6 consisting of a plurality of stacked piezoelectric elements are arranged at the two junction faces at least of the wall face in the longitudinal direction of an elastic body, and a circular driver 8 is arranged at the end face orthogonal to the longitudinal direction of the elliptic body, and a rotor 11 is retained rotatably by the elastic body while pressure-contacting with this driver 8. And, ultrasonic circular elliptic oscillation is excited in the position of the driver 8 by exciting the longitudinal oscillation and torsional oscillation at the same time, by applying AC voltage having phase difference each, to the plural piezoelectric elements 3 and 6, thus the rotor 11 is rotated by this ultrasonic elliptic oscillation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic vibrator using an electromechanical transducer as a drive source and an ultrasonic motor using the ultrasonic vibrator.

[0002]

2. Description of the Related Art In recent years, an ultrasonic motor has attracted attention as a new motor replacing an electromagnetic motor. This ultrasonic motor has the following advantages over a conventional electromagnetic motor.

(1) Low rotation and high torque can be obtained without gears. (2) Large holding force. (3) High resolution. (4) It is extremely quiet. (5) It does not generate magnetic noise and is not affected by noise.

As a conventional ultrasonic motor, there is an ultrasonic motor disclosed in Japanese Patent Laid-Open No. 62-203570 proposed by the present applicant. A conventional ultrasonic motor will be described below based on JP-A-62-203570.

The conventional ultrasonic motor disclosed in the publication is:
As shown in FIG. 20, the thickness-slip piezoelectric element 51 is sandwiched between the openings of the U-shaped member 52, and the pair of thickness-longitudinal piezoelectric elements 5 are formed on both shoulders of the outer surface of the coupling end of the U-shaped member 52.
3a and 53b are attached to form an ultrasonic oscillator, and a rotor 54 having a shaft 54a is arranged in a pressed state so that one side surface can contact the thickness longitudinal piezoelectric elements 53a and 53b.

Next, the operation of the ultrasonic motor using the ultrasonic vibrator will be described. Thickness sliding piezoelectric element 51
An alternating voltage having the same frequency as the natural frequency of the pendulum vibration (torsional vibration) of the U-shaped member 52 is applied to excite the torsional vibration.

At the same time, an alternating voltage having the same frequency as that described above is applied to the thickness vertical oscillators 53a and 53b to simultaneously excite vertical vibrations. When these torsional vibration and longitudinal vibration are excited, the rotor 54 can be rotated in a fixed direction. When the torsional vibration and the longitudinal vibration are excited in opposite phases, the rotor 54 can be rotated in the opposite direction.

[0008]

However, the above-mentioned conventional ultrasonic motor has the following problems. (1) As the ultrasonic oscillator, two types of piezoelectric elements, a sliding piezoelectric element and a thickness longitudinal piezoelectric element, are required, which complicates the structure. (2) In the case of an ultrasonic motor using the ultrasonic vibrator, the sliding piezoelectric element 51 and the thickness longitudinal piezoelectric elements 53a, 5
Since one or two plate-shaped piezoelectric elements are used for all 3b, the driving voltage becomes as high as several hundreds Vp-p, and low voltage driving cannot be performed.

Therefore, the present invention provides an ultrasonic transducer which does not require two types of piezoelectric elements and can be simplified in construction. The present invention also provides an ultrasonic motor that can be driven at a low voltage.

[0010]

An ultrasonic transducer according to a first aspect of the present invention is formed in a rectangular shape with an elastic body having joint surfaces formed on at least two surfaces of a wall surface along the longitudinal direction. At the same time, a plurality of piezoelectric elements having a constant displacement angle with respect to one side thereof and arranged on at least two joint surfaces of the wall surface of the elastic body and an end surface orthogonal to the longitudinal direction of the elastic body. Having an annular driver arranged,
By applying an alternating voltage having a phase difference to each of the plurality of piezoelectric elements, longitudinal vibration and torsional resonance vibration are simultaneously excited to excite ultrasonic elliptical vibration at the position of the driver. It is a feature.

An ultrasonic motor according to a second aspect of the present invention is formed into a rectangular shape with an elastic body having a joint surface formed on at least two surfaces of a wall surface along the longitudinal direction, and
A plurality of piezoelectric elements arranged on at least two joint surfaces of the wall surface of the elastic body and having a displacement direction having a constant oblique angle with respect to one side, and arranged on an end surface orthogonal to the longitudinal direction of the elastic body. The ultrasonic transducer is formed by the annular driving element, and the rotor is rotatably held by the elastic body while being in pressure contact with the driving element, and each of the plurality of piezoelectric elements has a phase difference. By applying an alternating voltage, longitudinal vibration and torsional resonance vibration are simultaneously excited to excite ultrasonic elliptical vibration at the position of the driver, and the ultrasonic elliptical vibration drives the rotor to rotate. It is characterized by.

According to a third aspect of the present invention, the plurality of piezoelectric elements in the ultrasonic motor according to the second aspect are
A laminated type consisting of a laminated structure of a large number of piezoelectric elements, each of which has a diagonal arrangement as a whole by shifting the position stepwise, and which alternately has internal electrodes in which the ends are exposed on the back surface side and the front surface side. It is characterized by using a piezoelectric element.

According to a fourth aspect of the present invention, the plurality of piezoelectric elements in the ultrasonic motor according to the second aspect are
A laminated piezoelectric element having a laminated structure of a large number of piezoelectric elements alone, which are provided with internal electrodes whose ends are exposed alternately on the back surface side and the front surface side, and cut out at a predetermined angle with respect to the lamination direction of the piezoelectric element single bodies. It is characterized by using.

According to a fifth aspect of the invention, in the ultrasonic motor according to the second aspect of the invention, the plurality of piezoelectric elements are
Ends of a large number of internal electrodes arranged in rows in each layer are alternately exposed on the back surface side and the front surface side, and a large number of piezoelectric element single layers in which a large number of internal electrodes arranged in rows are alternately displaced It is characterized by using a laminated piezoelectric element having a structure.

In the ultrasonic vibrator according to the invention as defined in claim 1, it is formed in a rectangular shape in which at least two surfaces of a wall surface along the longitudinal direction of the elastic body are arranged in a joint surface, and a displacement direction with respect to one side thereof. By applying an alternating voltage having a phase difference to a plurality of piezoelectric elements having a constant oblique angle, longitudinal vibration and torsional resonance vibration are excited at the same time, thereby orthogonal to the longitudinal direction of the elastic body. The ultrasonic elliptical vibration can be excited at the position of the annular driver arranged on the end face.

As a result, it is not necessary to use two types of piezoelectric elements such as the thickness-sliding piezoelectric oscillator and the thickness-longitudinal piezoelectric oscillator as in the conventional example, and a simple ultrasonic vibration having a configuration using one type of piezoelectric element is used. Child can be provided.

In the ultrasonic motor according to the second aspect of the present invention, the elastic body is formed in a rectangular shape which is arranged on at least two surfaces of the wall surface along the longitudinal direction of the elastic body, and the displacement direction is on one side thereof. By applying an alternating voltage having a phase difference to a plurality of piezoelectric elements having a constant oblique angle, longitudinal vibration and torsional resonance vibration are excited at the same time, whereby an end surface orthogonal to the longitudinal direction of the elastic body. The ultrasonic elliptical vibration is excited at the position of the annular driving element arranged at. Thus, the rotor rotatably held by the elastic body can be rotationally driven while being in pressure contact with the driver.

According to the second aspect of the invention,
It is possible to provide an ultrasonic motor that uses an ultrasonic vibrator having a simple configuration using one type of piezoelectric element as a drive source.

According to the third aspect of the invention, the plurality of piezoelectric elements in the ultrasonic motor according to the second aspect of the invention are arranged in a diagonal manner as a whole by shifting their positions stepwise. Since it is constructed by using a laminated piezoelectric element composed of a laminated structure of a large number of piezoelectric element units, which are alternately provided with internal electrodes whose ends are exposed on the back surface side and the front surface side, Compared to the case of using two types of plate-shaped piezoelectric elements such as a thickness-sliding piezoelectric vibrator and a thickness-longitudinal piezoelectric vibrator, the vibration output of the piezoelectric element becomes large, and conversely driving when the same rotational driving force is obtained. The voltage can be reduced.

According to a fourth aspect of the present invention, in the plurality of piezoelectric elements in the ultrasonic motor according to the second aspect of the present invention, the internal electrodes are arranged such that the ends are alternately exposed on the back surface side and the front surface side. The laminated piezoelectric element is composed of a laminated structure of a large number of piezoelectric elements alone, and the laminated piezoelectric element cut out at a predetermined angle with respect to the lamination direction of the piezoelectric element is used. It becomes larger than in the case of the invention according to claim 3, and a higher torque can be obtained.

According to the fifth aspect of the invention, in the plurality of piezoelectric elements in the ultrasonic motor according to the second aspect of the invention, the ends of the plurality of internal electrodes arranged in a row in each layer are alternately arranged on the back surface. Side and front surface side, a large number of piezoelectric elements are used because they use a laminated piezoelectric element having a laminated structure of a large number of single piezoelectric elements in which a large number of internal electrodes arranged in rows are alternately displaced. A large number of internal electrodes arranged in a row can be formed by two electrode patterns in which each layer is alternately repeated, and there is no portion to be discarded by cutting out.
As a result, the piezoelectric element can be simplified and the cost can be reduced, and the price of the ultrasonic motor can be reduced.

[0022]

Embodiments of the present invention will be described in detail below.

[First Embodiment] First, an ultrasonic transducer according to a first embodiment of the present invention will be described with reference to FIG.

The ultrasonic transducer shown in FIG. 1 has a substantially cylindrical shape,
At least 2 at approximately the center of the wall surface along the longitudinal direction
The elastic body 1 made of brass is provided on four or more surfaces, that is, four bonding surfaces 1a each having a rectangular shape and intersecting angles of right angles are provided on each of the four surfaces, and the piezoelectric elements 3 to 6 are provided for the respective bonding surfaces 1a. Are bonded using an adhesive.

A cylindrical holding member 2 is fitted to the upper cylindrical portion 1b of the elastic body 1 in a state where the upper edges of the piezoelectric elements 3 to 6 are in pressure contact with each other, and the holding member 2 is fixed with a screw 7. It is used and fixed to the upper cylindrical portion 1b. Further, an annular driving element 8 is provided on the end face 1c orthogonal to the longitudinal direction of the elastic body 1.
Are fixed by adhesion.

Next, a manufacturing process of the ultrasonic transducer of the first embodiment will be described with reference to FIGS.

As shown in FIG. 2, the elastic body 1 made of brass is used.
The piezoelectric elements 3 to 6 are arranged by applying an adhesive to each joint surface 1a of the above, and the cylindrical holding member 2 preloads the upper edges of the piezoelectric elements 3 to 6 along the longitudinal direction of the elastic body 1. Then, the holding member 2 is fixed to the upper cylindrical portion 1b by using the screw 7. At this time, in order to strengthen the bond between the holding member 2 and the elastic body 1, an adhesive may be used together with the screw 7.

Further, an annular driving element 8 is adhered and fixed to the end face 1c of the elastic body 1 which is orthogonal to the longitudinal direction to obtain the ultrasonic transducer shown in FIG.

Next, an ultrasonic motor using the ultrasonic vibrator and a method for manufacturing the ultrasonic motor will be described with reference to FIGS.

In the ultrasonic motor shown in FIG. 4, of the piezoelectric elements 3 to 6 of the ultrasonic oscillator, electric wires for applying electric power are attached to the positive electrodes of the piezoelectric elements 3 and 4, and these are set to the B phase. Electric wires for applying electric power are attached to the positive electrodes of 5 and 6 to make them the A phase, and the negative electrodes of the piezoelectric elements 3 to 6 are GND through the elastic body 1 and the holding screw 10 attached to the elastic body 1. To be a pole.

Further, the ultrasonic motor comprises a rotor 11 which is rotatably supported by the elastic body 1 while being in contact with the annular driving element 8 of the ultrasonic oscillator.

The rotor 11 is fitted on a bearing 12 mounted on a rotor fixing screw 9 mounted on the elastic body 1. Further, the spring 13 arranged around the rotor fixing screw 9 is pressed to the bearing 12 side by the nut 14 screwed to the rotor fixing screw 9, whereby the rotor 11 is rotated.
Is pressed against the upper surface of the annular drive element 8.

As a result, the rotor 11 is rotatably supported by the elastic body 1 while being pressed against the upper surface of the driver element 8.

Next, the manufacturing process of the ultrasonic motor will be described. As shown in FIG. 5, the elastic body 1 is provided with a hole 15 penetrating the central portion in the longitudinal direction thereof, and a screw 16 is provided at a substantially central portion of the hole 15.

In FIG. 5, the rotor fixing screw 9 is inserted into the hole 15 from the upper side and screwed into the screw 16, and the holding screw 10 is inserted from the lower side and screwed into the screw 16. The holding screw 10 supports the entire ultrasonic motor.

Next, as shown in FIG. 6, the rotor fixing screw 9 protruding upward from the upper cylindrical portion 1b of the elastic body 1 penetrates through the bearing 12 fitted in the central portion of the rotor 11, and the rotor 11 is fixed. The spring 13 is arranged on the upper surface of the annular driving element 8 and the spring 13 is fitted around the rotor fixing screw 9 so that the nut 14
Is screwed into the rotor fixing screw 9 so that the rotor 11 is pressed against the upper surface of the driver 8 and the elastic body 1 is pressed.
It is rotatably supported by. Thereby, the ultrasonic motor shown in FIG. 4 can be obtained.

Here, the structure of the piezoelectric elements 3 to 6 will be described with reference to FIGS. 7 to 9.

FIG. 7 shows the arrangement of the internal electrodes 17 in the piezoelectric elements 3 and 4, and FIG. 8 shows the arrangement of the internal electrodes 17 in the piezoelectric elements 5 and 6. In addition, FIG.
Shows a laminated structure of a laminated piezoelectric element composed of a large number of single piezoelectric elements 18 constituting the piezoelectric elements 3 to 6.

As shown in FIG. 9, each piezoelectric element 3 to 6 is composed of a laminated piezoelectric element composed of a large number of single piezoelectric elements 18, and each individual single piezoelectric element 18 has a quadrangular shape. 7 are formed such that the internal electrodes 17 are slightly displaced according to the stacking order, and the ends of the piezoelectric elements 17 are alternately exposed on the back surface and the front surface of the paper in FIG. 7 or 8. .

That is, in the case of the laminated piezoelectric element which constitutes the piezoelectric elements 3 and 4, each internal electrode 17 of a large number of single piezoelectric elements 18 has a diagonal line shape extending from the upper right corner to the lower left corner as shown in FIG. In the case of a laminated piezoelectric element that is arranged in a row and constitutes the piezoelectric elements 5 and 6, a large number of piezoelectric element single units 1
As shown in FIG. 8, the internal electrodes 17 of No. 8 are arranged in a diagonal line from the upper left corner to the lower right corner.

In each of the piezoelectric elements 3 to 6 having such a structure, each internal electrode 17 on the front surface side of the paper in FIG. 7 or 8 is used as a positive electrode, and each internal electrode 17 on the back surface side of the paper is polarized as a negative electrode.

Then, the internal electrodes 17 of the piezoelectric elements 3 to 6 are made conductive by a conductive adhesive or the like, and electric wires for applying electric power are attached to the positive electrodes of the piezoelectric elements 3 and 4 to make them B phase, Electric wires for applying electric power are attached to the positive electrodes of the piezoelectric elements 5 and 6 to make them the A phase.

When the piezoelectric elements 3 to 6 are attached to the joint surfaces 1a of the elastic body 1, the internal electrode 17 corresponding to the negative electrode of the piezoelectric elements 3 to 6 is electrically connected to the brass elastic body 1. Thus, the GND pole can be configured via the elastic body 1 and the holding screw 10 inserted through the elastic body 1.

Next, the operation of the ultrasonic motor using the above-mentioned ultrasonic oscillator will be described with reference to FIGS.

When a positive voltage is applied to the piezoelectric elements 3 and 4 of the ultrasonic motor, the piezoelectric elements 3 and 4 are respectively moved as shown in FIG.
When the piezoelectric elements 3 and 4 vibrate in a diagonal direction indicated by a solid line and a negative voltage is applied, the piezoelectric elements 3 and 4 vibrate in a diagonal direction indicated by a chain line in FIG.

Similarly, the piezoelectric element 5 of the ultrasonic motor,
When a positive voltage is applied to the piezoelectric elements 6, the piezoelectric elements 5 and 6 vibrate in a diagonal direction indicated by solid lines in FIG. 11, and when a negative voltage is applied, the piezoelectric elements 5 and 6 are respectively moved to the direction shown in FIG.
It vibrates in the diagonal direction indicated by the alternate long and short dash line.

When AC voltages of the same phase are applied to the A-phase and B-phase of the ultrasonic motor, the piezoelectric elements 3 and 4 and the piezoelectric elements 5 and 6 fixed to the elastic body 1 are shown in FIGS. It vibrates in the same phase while repeating the deformation vibration as shown by 11. As a result, the elastic body 1 performs longitudinal vibration or bending vibration.

When the frequency of the AC voltage applied to the A phase and the B phase is made to match the resonance frequency of the longitudinal vibration of the elastic body 1 and does not match the resonance frequency of the bending vibration, only the longitudinal vibration is generated. be able to.

Next, when the phases of the AC voltage applied to the A phase and the B phase of the ultrasonic motor are made to differ by 180 degrees, the piezoelectric elements 3 and 4 and the piezoelectric elements 5 and 6 are respectively shown in FIGS. 10 and 11. While repeating the deformation vibration as shown, it vibrates in the opposite phase. As a result, the elastic body 1 causes torsional vibration.

Then, by making the frequency of the AC voltage applied to the A phase and the B phase match the resonance frequency of the torsional vibration, the torsional resonance vibration can be generated in the elastic body 1.

From the above consideration, the shape of the elastic body 1 is adjusted to make the longitudinal primary resonance vibration and the torsion primary resonance vibration coincide with each other, and the A phase and the B phase are AC voltages different in phase from each other by 90 degrees. By applying, the longitudinal primary resonance vibration and the torsion primary resonance vibration are generated at the same time, and as a result, ultrasonic elliptical vibration is generated at the position of the driver element 8 fixed to the end surface of the elastic body 1.

The direction of rotation of this ultrasonic elliptical vibration is the above A
The directions of the AC voltage applied to the B phase are opposite to each other depending on whether the phase of the AC voltage applied to the B phase is +90 degrees or −90 degrees with respect to the AC voltage applied to the phase. The rotor 11, which is in pressure contact with the driver element 8 that performs ultrasonic elliptical vibration, rotates according to the rotation direction of the ultrasonic elliptical vibration.

According to the ultrasonic vibrator of the first embodiment described above, it is not necessary to use two types of piezoelectric elements such as the thickness sliding piezoelectric vibrator and the thickness longitudinal piezoelectric vibrator as in the conventional example,
Since the piezoelectric elements 3 to 6 of one type can be used, the structure can be simplified and the cost can be reduced.

Further, according to the ultrasonic motor of the first embodiment, it is possible to provide a low-cost ultrasonic motor which uses the ultrasonic vibrator as a drive source.

Further, according to the ultrasonic motor of the first embodiment, since the laminated piezoelectric elements are used as the piezoelectric elements 3 to 6, the thickness sliding piezoelectric vibrator and the thickness longitudinal piezoelectric vibrator as in the conventional example are used. Compared with the case where two types of plate-shaped piezoelectric elements are used, the vibration output of each piezoelectric element 3 to 6 is large, and conversely, the drive voltage when the same rotational drive force is obtained can be reduced.

Furthermore, since each piezoelectric element 3 to 6 is attached to the elastic body 1 in a pre-loaded state, destruction inside each piezoelectric element 3 to 6 is eliminated, and its life is greatly extended. You can

Although the four piezoelectric elements 3 to 6 are attached to the elastic body 1 in the first embodiment, for example, the piezoelectric element 3 and the piezoelectric element 5 are attached to the elastic body 1 so as to oppose each other. Even in this case, it is possible to rotate the rotor 11 by generating vertical vibration and torsional vibration similar to those in the first embodiment.

[Second Embodiment] Next, FIG. 12 to FIG.
Embodiment 2 of the present invention will be described with reference to FIG.

In the second embodiment, an ultrasonic vibrator and an ultrasonic motor having the same structure as in the first embodiment are adopted, but the piezoelectric element 3 in the first embodiment is used.
To 6 instead of the piezoelectric element 23 shown in FIGS.
24 and the piezoelectric elements 25 and 26 are used.

Piezoelectric elements 23, 24 and piezoelectric elements 25, 2
6 uses a laminated piezoelectric element having a laminated structure of a large number of single piezoelectric elements 28. That is, in FIG.
As shown in FIG. 12, a large number of piezoelectric element units 30 each having the internal electrodes 27 arranged so that the end portions are exposed on the back surface side and the front surface side of the paper sheet alternately seen in FIGS. Is polarized as a negative electrode and the surface side as a positive electrode. Then, as shown in FIG. 15, for a laminated body of a large number of piezoelectric element plates 30,
The piezoelectric element 30 is cut out with two kinds of predetermined angles symmetrically arranged with respect to the stacking direction of the piezoelectric element 30.
3 and 24 and piezoelectric elements 25 and 26.

Further, an insulating ceramic plate 31 is adhered to the end faces of the piezoelectric elements 23 and 24 and the piezoelectric elements 25 and 26 so that the internal electrodes 27 are not exposed at the end faces.

Also in the case of the ultrasonic vibrator and ultrasonic motor using the piezoelectric elements 23 and 24 and the piezoelectric elements 25 and 26, the piezoelectric elements 23 and 24 and the piezoelectric element 2 are used.
Similarly to the piezoelectric elements 3 and 4 and the piezoelectric elements 5 and 6, the piezoelectric elements 5 and 26 are deformed and vibrated in the same manner as shown in FIGS. As a result, vertical 1
The secondary resonance vibration and the torsional primary resonance vibration are generated at the same time, ultrasonic elliptical vibration is generated at the position of the driver element 8 fixed to the end surface of the elastic body 1, and the rotor 11 can be rotationally driven.

Further, in the case of the ultrasonic transducer and the ultrasonic motor of the second embodiment, the activation force of the deformation of the laminated structure of each piezoelectric element unit 30 having the internal electrode 27 becomes larger than that in the first embodiment. , Higher torque can be obtained.

[Third Embodiment] Next, FIG. 16 to FIG.
The third embodiment of the present invention will be described with reference to FIG.

In the third embodiment, an ultrasonic transducer and an ultrasonic motor having the same structure as in the first embodiment are adopted, but the piezoelectric element 3 in the first embodiment is used.
Instead of 6 to 6, the piezoelectric element 43 shown in FIGS.
The feature is that 44 and piezoelectric elements 45 and 46 are used.

The piezoelectric elements 43 and 44 and the piezoelectric element 4
Reference numerals 5 and 46 each use a laminated piezoelectric element having a laminated structure of a large number of single piezoelectric elements 28. That is,
As shown in FIG. 18, in the case of the laminated piezoelectric element according to the third embodiment, a large number of internal electrodes 4 arranged in rows in each layer.
Each end of 7 is alternately exposed on the back surface side and the front surface side as seen in FIGS. 16 and 17, and a large number of internal electrodes 47 arranged in rows are arranged.
A laminated structure of a large number of single piezoelectric elements 50 in which the respective layers are alternately displaced is adopted. In this case, the first layer, the third layer,
The electrode patterns of the single piezoelectric element 50 are the same, and the electrode patterns of the second and fourth piezoelectric elements 50 are the same. Further, the back side is a negative electrode and the front side is a positive electrode.

As a result, the internal electrodes 47 of each layer of the laminated piezoelectric element are polarized as shown by the arrows in FIG.

Further, as shown in FIGS. 16 and 17, an external electrode 51 is provided in a diagonal direction on each surface of the piezoelectric elements 43 and 44 and the piezoelectric elements 45 and 46.

In the case of an ultrasonic transducer and an ultrasonic motor using such piezoelectric elements 43 and 44 and piezoelectric elements 45 and 46, when an AC voltage is applied to each internal electrode 47, a partial view of FIG. It deforms in the polarization direction indicated by the arrow. In addition, the piezoelectric elements 43 and 44 and the piezoelectric elements 45 and 4
When viewed as a whole, only the portion where the external electrode 51 is provided in the diagonal direction is deformed in the polarization direction shown by the arrow in FIG.
No deformation occurs in other parts.

As a result, the piezoelectric elements 43 and 44 are deformed in a substantially diagonal direction as in the case shown in FIG.
5 and 46 are deformed in a substantially diagonal direction as in the case shown in FIG. By utilizing such deformation of the piezoelectric elements 43, 44 and the piezoelectric elements 45, 46, longitudinal primary resonance vibration and torsional primary resonance vibration are simultaneously generated, and the driver element 8 fixed to the end surface of the elastic body 1 is produced. The ultrasonic elliptical vibration is generated at the position of, and the rotor 11 can be rotationally driven.

In the case of the ultrasonic vibrator and ultrasonic motor using the piezoelectric elements 43 and 44 and the piezoelectric elements 45 and 46, the same effect as in the case of the first embodiment can be exhibited.

Further, a large number of internal electrodes 47 arranged in a row of a large number of single piezoelectric elements 50 can be formed by two electrode patterns in which each layer is alternately repeated, and there is no portion to be discarded by cutting out, whereby the piezoelectric elements 43 to 43 can be formed. 46, simplification and cost reduction can be achieved, and the price of the ultrasonic motor can be reduced.

[0073]

According to the first aspect of the present invention, it is not necessary to use two types of piezoelectric elements such as the thickness sliding piezoelectric vibrator and the thickness longitudinal piezoelectric vibrator as in the conventional example, and one type of piezoelectric element is used. It is possible to provide an ultrasonic transducer having a simple configuration used.

According to the second aspect of the invention, it is possible to provide an ultrasonic motor using an ultrasonic vibrator as a drive source, which has a simple structure using one type of piezoelectric element and can realize a low cost.

According to the third aspect of the present invention, it is possible to provide an ultrasonic motor which has the same effects as the second aspect of the invention and which can reduce the driving voltage of the piezoelectric element.

According to the invention described in claim 4, it is possible to provide an ultrasonic motor capable of obtaining the same effect as that of the invention described in claim 2 and obtaining a higher torque.

According to the invention described in claim 5, there is provided an ultrasonic motor having the same effect as that of the invention described in claim 2, simplification and price reduction of the piezoelectric element, and cost reduction. be able to.

[Brief description of drawings]

FIG. 1 is a perspective view showing an ultrasonic transducer according to a first embodiment of the present invention.

FIG. 2 is an exploded perspective view showing a manufacturing process of the ultrasonic transducer according to the first embodiment of the present invention.

FIG. 3 is an exploded perspective view showing a manufacturing process of the ultrasonic transducer according to the first embodiment of the present invention.

FIG. 4 is a perspective view showing the ultrasonic motor according to the first embodiment of the present invention.

FIG. 5 is an end view showing a manufacturing process of the ultrasonic motor according to the first embodiment of the present invention.

FIG. 6 is a perspective view showing an ultrasonic motor manufacturing process according to the first embodiment of the present invention.

FIG. 7 is an explanatory diagram showing an arrangement of internal electrodes of the piezoelectric element according to the first embodiment of the present invention.

FIG. 8 is an explanatory diagram showing an arrangement of internal electrodes of the piezoelectric element according to the first embodiment of the present invention.

FIG. 9 is a perspective view showing a laminated structure of the piezoelectric element according to the first embodiment of the present invention.

FIG. 10 is an explanatory diagram showing a deformed state of the piezoelectric element according to the first embodiment of the present invention.

FIG. 11 is an explanatory diagram showing a deformed state of the piezoelectric element according to the first embodiment of the present invention.

FIG. 12 is a side view showing a laminated structure of the piezoelectric element according to the second embodiment of the present invention.

FIG. 13 is a side view showing a laminated structure of the piezoelectric element according to the second embodiment of the present invention.

FIG. 14 is an explanatory diagram showing a laminated structure of the piezoelectric element according to the second embodiment of the present invention.

FIG. 15 is an explanatory diagram showing a cutout state of the piezoelectric element according to the second embodiment of the present invention.

FIG. 16 is a plan view of a piezoelectric element according to a third embodiment of the present invention.

FIG. 17 is a plan view of a piezoelectric element according to a third embodiment of the present invention.

FIG. 18 is an explanatory diagram showing a laminated structure of the piezoelectric element according to the third embodiment of the present invention.

FIG. 19 is an explanatory diagram showing a polarized state of the piezoelectric element according to the third embodiment of the present invention.

FIG. 20 is a perspective view showing a conventional ultrasonic transducer.

[Explanation of symbols]

 1 Elastic Body 1a Bonding Surface 1b Upper Cylindrical Part 2 Holding Member 3 Piezoelectric Element 4 Piezoelectric Element 5 Piezoelectric Element 6 Piezoelectric Element 7 Screw 8 Driver 9 Rotor Fixing Screw 10 Holding Screw 11 Rotor 12 Bearing 13 Spring 14 Nut 17 Internal Electrode 18 Piezoelectric element alone

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazuhiro Awai 2-43-2 Hatagaya, Shibuya-ku, Tokyo Inside Olympus Optical Co., Ltd.

Claims (5)

[Claims] 1. An elastic body in which a joint surface is formed on at least two surfaces of a wall surface along the longitudinal direction, and the elastic body is formed in a rectangular shape, and a displacement direction has a constant oblique angle with respect to one side thereof. A plurality of piezoelectric elements arranged on at least two joint surfaces of the wall surface of the elastic body, and an annular driving element arranged on an end surface orthogonal to the longitudinal direction of the elastic body, And applying an alternating voltage having a phase difference to each other to excite longitudinal vibration and torsional resonance vibration at the same time to excite ultrasonic elliptical vibration at the position of the driver element. Oscillator. 2. An elastic body in which a joint surface is formed on at least two surfaces of a wall surface along the longitudinal direction, and the elastic body is formed in a rectangular shape, and a displacement direction has a constant oblique angle with respect to one side thereof. An ultrasonic transducer is constituted by a plurality of piezoelectric elements arranged on at least two bonding surfaces of the wall surface of the elastic body, and an annular driving element arranged on an end surface orthogonal to the longitudinal direction of the elastic body. A rotor rotatably held by the elastic body while being in pressure contact with the driver, and applying an alternating voltage having a phase difference to each of the plurality of piezoelectric elements to cause longitudinal vibration and torsional resonance vibration. Are simultaneously excited to excite ultrasonic elliptical vibration at the position of the driver, and the rotor is rotationally driven by the ultrasonic elliptical vibration. 3. The plurality of piezoelectric elements are arranged in a diagonal shape as a whole by shifting their positions stepwise, and are provided with internal electrodes arranged so that their ends are alternately exposed on the back surface side and the front surface side. 3. The ultrasonic motor according to claim 2, wherein a laminated piezoelectric element having a laminated structure of a large number of piezoelectric elements alone is used. 4. The plurality of piezoelectric elements are alternately arranged on the back surface side,
It is composed of a laminated structure of a large number of piezoelectric elements including internal electrodes whose ends are exposed on the front surface side, and uses a laminated piezoelectric element cut out at a predetermined angle with respect to the lamination direction of the piezoelectric elements. The ultrasonic motor according to claim 2. 5. In the plurality of piezoelectric elements, each end of a large number of internal electrodes arranged in a row in each layer is alternately exposed on the back surface side and the front surface side, and a large number of internal electrodes arranged in a row are alternately arranged in each layer. 3. The ultrasonic motor according to claim 2, wherein a laminated piezoelectric element having a laminated structure of a large number of piezoelectric elements that are misaligned with each other is used.