JPH10210767A - Oscillation actuator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an oscillation actuator in which a drive signal can be inputted surely and inexpensively while suppressing degradation of performance due to input of drive signal as mush as possible. SOLUTION: The oscillation actuator comprises a resilient body 12, a piezoelectric 13 fixed to the resilient body 12 and generating longitudinal and bending oscillations, first electrodes 14a, 14c and 14e for inputting a first phase drive signal to the piezoelectric 13, and second electrodes 14b, 14d and 14f for inputting a second phase drive signal to the piezoelectric 13 without touching the first electrodes 14a, 14c and 14e. The first electrodes 14a, 14c and 14e are interconnected through a first electrode joint 15 and the second electrodes 14b, 14d and 14f are interconnected through a second electrode joint 16.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an elastic body, an electromechanical transducer mounted on the elastic body to generate longitudinal vibration and bending vibration in the elastic body, and an electrode for inputting a drive signal to the electromechanical transducer. The present invention relates to a vibration actuator including:

[0002]

2. Description of the Related Art Conventionally, this type of vibration actuator has
An AC voltage is applied through an electrode to an electromechanical transducer (e.g., a piezoelectric body, an electrostrictive element, etc., hereinafter, generally referred to as a piezoelectric body) bonded to an elastic body, and a plurality of vibration modes (for example, There is known a structure in which a longitudinal force and a bending vibration) are generated in harmony to obtain a driving force and perform relative movement with a relative movement member that comes into contact with the elastic body.

[0003] For example, "Piezoelectric linear motor for moving optical pickup" (Mr. Yoshiro Tomikawa et al .: Proceedings of the 5th Electromagnetic Force-Related Dynamic Symposium, pp. 393-398), The structure and load characteristics are described in detail.

[0004] Also, a new ultrasonic motor (co-authored by Sadayuki Ueba and Yoshiro Tomikawa, pp. 145-146, published by Trikeps).
Page) shows a self-propelled structure. This actuator has a flat plate shape, and is designed to have a shape in which the resonance frequencies of the first-order longitudinal vibration mode and the sixth-order bending vibration mode (or fourth and eighth-order modes) are very close to each other. Then, by applying two phases of an AC voltage having a frequency close to the two resonance frequencies to the piezoelectric body, the elastic body generates vibration in which the two modes are in harmony.

This elastic body has a projection at the antinode of the sixth mode of the bending vibration, and the driving force is obtained by the elliptical movement of the tip of the projection. FIG.
FIG. 4A is an explanatory view showing the structure of the vibrator 1 utilizing such vertical primary-flexural sixth vibration, and FIG.
4B is a perspective view of the bottom surface, and FIG. 4C is an explanatory diagram illustrating an example of a longitudinal primary-bending sixth vibration mode generated in the elastic body 2.

As shown in FIG. 4A, one flat surface of the rectangular flat elastic body 2 is made of PZT (lead zirconate titanate) formed in a thin plate shape so as to completely cover the flat surface. The piezoelectric body 3 is mounted, for example, by bonding.

The six independent electrodes 4a, 4b, 4c, 4d, 4e, 4 are located on the plane of the piezoelectric body 3, including the antinode position of the sixth-order bending vibration generated in the elastic body 2.
f is attached. On the other hand, the lower electrode 5 is mounted between the piezoelectric body 3 and the elastic body 2 so as to match the mounting range of the electrodes 4a to 4f as shown by the broken line in FIG. Electrode 4
When a drive voltage is applied between a to 4f and the lower electrode 5, the piezoelectric body 3 is excited, and the elastic body 2 generates vibration.

[0008] From a two-phase drive circuit provided in a drive signal generator (not shown), sin is applied to the electrodes 4a, 4c and 4e.
By applying a driving signal of a wave signal and a driving signal of a cos signal to the electrodes 4b, 4d and 4f, respectively,
Can be excited to generate a first-order longitudinal vibration and a sixth-order bending vibration in the elastic body 2.

Here, a drive signal is input from an external power supply (not shown) to each of the electrodes 4a to 4f.
Leads were soldered one by one to a to 4f, and this was performed via the leads.

[0010]

However, soldering lead wires one by one to the electrodes 4a to 4f in this manner is not desirable in view of the number of soldering operations, and increases the number of operations. There is a possibility that the production cost will increase.

Further, as the number of soldering points increases, the number of occurrences of defective soldering increases, which may lower the yield of the manufactured vibration actuator. Further, although a lead wire is not directly attached to the elastic body 2, a large number of lead wires are attached to the electrodes 4a to 4f which are indirectly attached to the elastic body 2.
May be restricted, and the driving efficiency of the vibration actuator 1 may be reduced.

[0012]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and it is possible to input a drive signal inexpensively and reliably. An object of the present invention is to provide a vibration actuator that can be suppressed as much as possible.

According to a first aspect of the present invention, there is provided an electromechanical transducer having a rectangular flat plate-like shape, an electromechanical transducer mounted on the elastic body to generate longitudinal vibration and bending vibration in the elastic body, and a first electromechanical transducer.
A plurality of first electrodes for inputting a phase drive signal, and a second phase drive signal input to the electromechanical transducer and
A vibration actuator including a plurality of second electrodes that do not contact the electrodes, wherein the plurality of first electrodes are connected to each other via a first electrode connection unit, and / or the plurality of second electrodes are connected to each other. It is characterized by being connected via the second electrode connection part.

According to a second aspect of the present invention, in the vibration actuator according to the first aspect, each of the plurality of first electrodes and the plurality of second electrodes is provided on a surface of the electromechanical transducer. I do.

[0015] The invention of claim 3 is claim 1 or claim 2.
A plurality of first actuators.
The electrode and the plurality of second electrodes are separated from each other, and are alternately provided in the longitudinal direction of the elastic body.

According to a fourth aspect of the present invention, in the vibration actuator according to the third aspect, the area of the first electrode connection is smaller than the area of the adjacent second electrode, and the area of the second electrode connection is smaller. , And is smaller than the area of the adjacent first electrode.

According to a fifth aspect of the present invention, there is provided the first to fourth aspects.
In the vibration actuator described in any one of the above, the first electrode and the second electrode are provided at positions including antinode positions of bending vibration generated in the elastic body.

The invention according to claim 6 is the invention according to claims 1 to 5.
In the vibration actuator described in any one of the above, the first electrode, the second electrode, the first electrode connection portion, and the second electrode
Each of the electrode connecting portions is formed by a printing method or a thin film forming method.

According to a seventh aspect of the present invention, in the vibration actuator according to the sixth aspect, the first electrode and the first electrode connecting portion are integrally formed, and the second electrode and the second electrode connecting portion are integrally formed. It is characterized by being formed.

[0020] The invention of claim 8 provides an elastic body in the shape of a rectangular plate, an electromechanical interconversion element mounted on the elastic body to generate longitudinal vibration and bending vibration in the elastic body, and an electric energy from the electromechanical interconversion element. And a plurality of electrodes for taking out the plurality of electrodes, wherein the plurality of electrodes are connected to each other via an electrode connection part.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings. In the following description of each embodiment, an ultrasonic actuator using an ultrasonic vibration region is used as an example of the vibration actuator.

FIG. 1 is a top view showing the structure of the ultrasonic actuator 10 of the first embodiment, and FIG. 2 is a bottom view of the ultrasonic actuator 10. The ultrasonic actuator 10 of the present embodiment is different from the conventional ultrasonic actuator only in the structure of the electrodes, and the other structures are the same. Therefore, the same parts will be briefly described. .

As shown in FIG. 1, a vibrator 11 used for an ultrasonic actuator 10 of the present embodiment is an elastic body 12.
And a piezoelectric body 13 mounted on the elastic body 12 and generating a first-order longitudinal vibration and a sixth-order bending vibration in the elastic body 12 in harmony.
And first electrodes 14 a, 14 c and 14 e mounted on the surface of the piezoelectric body 13 and inputting a first phase drive signal, and a second electrode 1 inputting a second phase drive signal to the piezoelectric body 13
4b, 14d and 14f.

The first electrodes 14a, 14c and 14e, the second
The electrodes 14b, 14d, and 14f all have a rectangular cross section, are separated from each other, and are insulated. Also, the first electrodes 14a, 14c and 14e and the second electrodes 14b and 14d
And 14f are separated from each other and insulated. As described above, the first electrodes 14a, 14c, and 14e and the second electrodes 14b, 14d, and 14f are spaced apart from each other and arranged alternately and continuously in the longitudinal direction of the elastic body 12. The mounting positions of the electrodes 14 a to 14 f are positions including antinode positions of bending vibration generated in the elastic body 12.

Here, in the ultrasonic actuator 10 of the present embodiment, the first electrodes 14a, 14c and 14e are linear electrode-formed first electrode connecting portions (line electrodes) near the upper edge of the elastic body 12. 15 are connected. Further, in the present embodiment, the second electrodes 14b, 14d, and 14f are also connected by the second electrode connection portion (line electrode) 16 formed linearly near the lower end of the elastic body 12.

The second electrodes 14 b and 14 d are not formed up to the end of the elastic body 12 in order to prevent contact with the first electrode connection portion 15. The first electrodes 14 c and 14 e are not formed up to the end of the elastic body 12 in order to prevent contact with the second electrode connection portion 16.

As described above, the area of the first electrode connection 15 is smaller than the area of the adjacent second electrodes 14b and 14d, and the area of the second electrode connection 16 is equal to the area of the adjacent first electrodes 14c and 14e. Smaller than the area.

In this embodiment, the first electrodes 14a, 14c
And 14e, the second electrodes 14b, 14d and 14f and the first
The electrode connection part 15 and the second electrode connection part 16 are
Is formed into a thin film by a printing method such as a silk printing method. That is, since the piezoelectric body 13 is formed by masking a predetermined pattern on the surface thereof, it can be formed easily and surely.

In this embodiment, as shown in FIG. 2, a lower electrode 17 is formed between the piezoelectric body 13 and the elastic body 12. The lower electrode 17 is connected to the first electrode connecting portion 1.
5, notched to avoid a portion corresponding to the second electrode connection portion 16. As a result, the facing electrode between the first electrode connecting portion 15 and the second electrode connecting portion 16 and the lower electrode 17 does not exist. Therefore, the first electrode connection portion 1
5. It is possible to reduce the occurrence of the vibration generated by the second electrode connection portion 16.

That is, when the lower electrode 17 has a rectangular flat plate shape as shown in FIG. 4B, for example, in the portion A of FIG. 2, the electrode 14b and the first electrode connecting portion 15 respectively have a sine signal and a cos signal. It works by. This is because the sin signal and the cos are at the same antinode position of the bending vibration generated in the elastic body 12.
The signals coexist, and the vibrations generated by the respective drive signals are canceled out, which is not desirable in terms of the vibration generation efficiency. Therefore, in the present embodiment, the first electrode connecting portion 15 and the second electrode
This prevents two sets of drive voltages having phases opposite to each other from being applied in a range where each of the electrode connection portions 16 is formed.

According to the present embodiment, two electrode groups (first electrodes 14a, 14c and 14e and second electrodes 14b, 14d and 14f) to which AC voltages of the same phase are applied are respectively connected.

Therefore, the first electrodes 14a, 14c, 1
By soldering a lead wire to 4e and one place of the first electrode connection part 15, and soldering a lead wire to one place of the second electrodes 14b, 14d, 14f and the second electrode connection part 16, A drive signal can be applied to all of the electrodes 14a to 14f.

In the present embodiment, the lead wire is
It is desirable to connect to the electrode by P in the above. This point P is a node position of the bending vibration generated in the elastic body 12, so that the attenuation of the bending vibration can be suppressed.

As described above, according to the present embodiment, the number of lead wire soldering operations can be greatly reduced, and the number of operation steps can be reduced, thereby suppressing an increase in manufacturing cost.

Further, according to the present embodiment, the number of soldering failures is reduced by reducing the number of soldering points, and a reduction in the yield of the manufactured vibration actuator can be suppressed.

Further, according to the present embodiment, the elastic body 12
The degree of freedom of the mounting position of the lead wire with respect to can be increased, so that the antinode position of the vibration generated in the elastic body 12 can be reliably avoided. Thereby, the restraint of the vibration generated in the elastic body 12 is suppressed, and a decrease in the driving efficiency of the vibration actuator 10 can be prevented.

(Second Embodiment) FIG. 3 is an explanatory view showing the structure of an ultrasonic actuator according to a second embodiment.
FIG. 3A is a top view, and FIG. 3B is an explanatory diagram illustrating an example of a longitudinal primary-bending quaternary vibration mode generated in the elastic body 12.

The ultrasonic actuator 20 of the present embodiment
Is an ultrasonic actuator 20 provided with a vibrator 21 utilizing vertical primary-bending fourth vibration. Such an ultrasonic actuator 20 has been described in detail by the above-described “piezoelectric linear motor for moving the optical pickup” or “new ultrasonic motor”, and since its structure is known, This will be briefly described.

The ultrasonic actuator 20 of the present embodiment
Is a rectangular plate-shaped elastic body 21, a piezoelectric body 22 which is an electromechanical interconversion element mounted on the elastic body 21 and generates longitudinal vibration and bending vibration on the elastic body 21, and extracts electric energy from the piezoelectric body 22. Two vibration detection electrodes 23a, 23
b, and the vibration detecting electrodes 23a and 23b are connected to each other via a line electrode 24 which is an electrode connecting portion.

The ultrasonic actuator 20 of the present embodiment
Generates the first longitudinal vibration and the fourth bending vibration in the elastic body 21, so that the first electrodes 25 a and 25 c and the first electrode 25 a and 25 c The two electrodes 25b and 25d are attached and mounted. In the present embodiment, as in the first embodiment, the first electrodes 25a and 25
c denotes a first electrode connection (line electrode) 26, and second electrodes 25b and 25d denote a second electrode connection (line electrode) 27.
Are connected.

The first electrode connection 26 and the second electrode connection 27
Since each operation is the same as that of the first embodiment, further description is omitted. In the present embodiment, the piezoelectric body 22 that generates electric energy by the vibration generated in the elastic body 21
The electrodes 23a and 23b for vibration detection mounted on are connected by a line electrode 24. Therefore, a lead wire for extracting electric energy may be soldered to an appropriate one of the vibration detection electrodes 23a and 23b and the line electrode 24.
The number of soldering points can be reduced.

Thus, according to the present embodiment, the same effects as in the first embodiment can be obtained for the vibration detecting electrodes 23a and 23b. Further, according to the present embodiment, the electric energy detected from the vibration detection electrodes 23a and 23b is detected in a superimposed manner. Therefore, in the case of the related art in which the electric energy detected from the vibration detection electrodes 23a and 23b is individually extracted, a circuit or the like for electrically averaging the two extracted signals is required. Such a circuit becomes unnecessary, which is more desirable.

(Modification) In each of the embodiments described in detail above, the ultrasonic actuator is used as the vibration actuator. However, the vibration actuator according to the present invention is not limited to such a mode. The same applies to a vibration actuator using a region.

In each of the embodiments, a piezoelectric body is used as the electromechanical transducer. However, the vibration actuator according to the present invention is equally applicable to other elements that can convert electric energy into mechanical displacement. . An electrostrictive element other than the piezoelectric body can be exemplified.

Further, in each of the embodiments, the vibration actuator which generates the primary longitudinal vibration and the sixth or fourth bending vibration in the elastic body is taken as an example. It is not limited to a simple mode,
The same applies to a vibration actuator that generates a primary vibration or more and a secondary vibration or more.

In the first embodiment, the first electrode 14a
To 14e, second electrodes 14b to 14f, first electrode connection part 1
Each of the fifth electrode connection portion 16 and the second electrode connection portion 16 is formed in a thin film shape by a printing method. However, the vibration actuator according to the present invention is not limited to such an embodiment. May be formed.

Further, the first electrodes 14a to 14e connected by the first electrode connection portion 15 and the second electrodes 14b to 14f connected by the second electrode connection portion 16 are formed, for example, in a shape shown in FIG. It may be formed by cutting out by a cutter method or the like and bonding it to the surface of the piezoelectric body 13.
In this case, the first electrode connection 15 and the second electrode connection 16
Does not need to be formed on the same plane as the electrodes 14a to 14f, and may be configured to bend in the thickness direction of the elastic body 12 to prevent contact with the electrodes 14a to 14f. . By doing so, each of the electrodes 14a to 14a
4f can be fully mounted on the surface of the elastic body 12,
A decrease in driving force can be suppressed.

[Brief description of the drawings]

FIG. 1 is a top view illustrating a structure of an ultrasonic actuator according to a first embodiment.

FIG. 2 is a bottom view of the ultrasonic actuator according to the first embodiment.

3A and 3B are explanatory views showing the structure of an ultrasonic actuator according to a second embodiment, wherein FIG. 3A is a top view, and FIG. 3B is a longitudinal first-bending fourth-order vibration mode generated in an elastic body. It is explanatory drawing which shows an example of.

4A and 4B are explanatory views showing the structure of a conventional vibrator utilizing longitudinal primary-bending sixth order vibration. FIG. 4A is a top view, FIG.
4B is a bottom view, and FIG. 4C is an explanatory diagram showing an example of a longitudinal primary-bending sixth-order vibration mode generated in the elastic body.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Ultrasonic actuator 11 Vibrator 12 Elastic body 13 Piezoelectric body 14a, 14c, 14e 1st electrode 14b, 14d, 14f 2nd electrode 15 1st electrode connection part (line electrode) 16 2nd electrode connection part (line electrode) 17 Lower electrode

Claims (8)

[Claims] An electromechanical transducer mounted on the elastic body to generate longitudinal and bending vibrations in the elastic body; a first phase drive signal transmitted to the electromechanical transducer. And a plurality of second electrodes that input a second-phase drive signal to the electromechanical transducer and do not contact the first electrode. A vibration actuator, wherein the first electrodes are connected to each other via a first electrode connection, and / or the plurality of second electrodes are connected to each other via a second electrode connection. 2. The vibration actuator according to claim 1, wherein the plurality of first electrodes and the plurality of second electrodes are all provided on a surface of the electromechanical transducer. Actuator. 3. The vibration actuator according to claim 1, wherein the plurality of first electrodes and the plurality of second electrodes are separated from each other and alternately in a longitudinal direction of the elastic body. A vibration actuator, which is provided continuously. 4. The vibration actuator according to claim 3, wherein an area of the first electrode connection is smaller than an area of the adjacent second electrode, and an area of the second electrode connection is adjacent to the second electrode. The vibration actuator is smaller than the area of the first electrode. 5. The method according to claim 1, wherein:
In the vibration actuator described in the paragraph, the first electrode and the second electrode are provided at positions including antinode positions of the bending vibration generated in the elastic body. 6. Any one of claims 1 to 5
In the vibration actuator described in the paragraph, the first electrode, the second electrode, the first electrode connection portion, and the second electrode connection portion are all formed by a printing method or a thin film forming method. Characteristic vibration actuator. 7. The vibration actuator according to claim 6, wherein the first electrode and the first electrode connection are integrally formed, and the second electrode and the second electrode connection are integrally formed. A vibration actuator. 8. An elastic body having a rectangular flat plate shape, an electromechanical interconversion element mounted on the elastic body to generate longitudinal vibration and bending vibration on the elastic body, and extracting electric energy from the electromechanical interconversion element. A vibration actuator comprising: a plurality of electrodes; wherein the plurality of electrodes are connected to each other via an electrode connection unit.