JPH07264884A - Ultrasonic motor - Google Patents

Abstract

PURPOSE:To connect an electromechanical conversion element to driving signal supplying sections without deteriorating the performance of the electromechanical conversion element. CONSTITUTION:An ultrasonic motor 20 is provided with an electromechanical conversion element (piezoelectric body) 11 which is excited when driving signals are supplied, elastic body 12 which is joined with the element 11 and generates oscillatory waves when the element 11 is excited, and mobile body 13 which is brought into contact with the elastic body 12 and frictionally driven by the oscillatory waves. The motor 20 is also provided with conductive plates 21a-21d which are joined to at least parts of the electrodes of the element 11 and have external connecting sections arranged on the outside of the element 11 and driving signal supplying sections 22a-22d which are connected with the external connecting sections of the plates 21a-21d and supply the driving signals to the electrodes of the element 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic motor for exciting an electromechanical conversion element to generate a vibration wave in an elastic body, and frictionally driving a moving body by the vibration wave, and more particularly to an electrode of the electromechanical conversion element. And a drive signal supply unit.

[0002]

2. Description of the Related Art FIG. 6 is a perspective view showing an example of the configuration of a conventional ultrasonic motor of this type. This ultrasonic motor 10
Is composed of a piezoelectric body 11, an elastic body 12, a moving body 13 and the like. The piezoelectric body 11 is an electromechanical conversion element 1
It is excited by the supply of a drive signal and is fixed to the support 16 via a vibration absorbing material 15 such as felt. The elastic body 12 is bonded to the piezoelectric body 11 with an electrically conductive adhesive or the like, and generates a progressive vibration wave when the piezoelectric body 11 is excited. Moving body 13
Is pressed against the elastic body 12 and frictionally driven by the progressive vibration wave. Flexible printed circuit board 1
Reference numeral 4 (hereinafter referred to as “FPC 14”) is for supplying a drive signal to the piezoelectric body 11.

FIG. 7 is a plan view showing the contact surface side of the piezoelectric body 11 with the FPC 14, and FIG. 8 is a plan view showing the contact surface side of the piezoelectric body 11 with the elastic body 12. In FIG.
The piezoelectric body 11 includes an A-phase electrode portion 11a and a B-phase electrode portion 11b.
And a pickup section 11c and a GND (ground) section 11d between the A-phase electrode section 11a and the B-phase electrode section 11b. In FIG. 8, the A-phase electrode portion 11a and the B-phase electrode portion 11b of the piezoelectric body 11 are divided along the circumferential direction so that the poling directions are alternately opposite. These divided piezoelectric bodies 1
The electrodes of No. 1 are arranged at a pitch of λ / 2. The A-phase electrode section 11a and the B-phase electrode section 11b are provided with a phase difference of λ / 4 by the pickup section 11c. The entire length of the piezoelectric body 11 is an integral multiple of λ.

The FPC 14 is an A phase electrode portion 1 of the piezoelectric body 11.
1a, B-phase electrode section 11b, and pickup section 11c. When a voltage with a phase difference of 90 ° is applied from the FPC 14 to the A-phase electrode portion 11a and the B-phase electrode portion 11b of the piezoelectric body 11, a bending vibration vibration wave that advances in the circumferential direction is generated in the elastic body 12. The traveling direction of the vibration wave is determined by the positive / negative of the phase difference of the applied voltage.

When a frequency voltage is applied to the piezoelectric body 11, a vibration wave is generated not only in the elastic body 12 but also in the piezoelectric body 11 itself.
It is necessary to join the first electrode portions 11a to 11c so as not to cause poor contact. Conventionally, in order to securely fix the both, they are joined by soldering.

[0006]

However, the above-described conventional ultrasonic motor has the following problems when the conductor pattern of the FPC 14 and the electrode portions 11a to 11c of the piezoelectric body 11 are joined by soldering. First, when heat generated by soldering is transmitted to the piezoelectric body 11, the electrode portions 11a to 11c formed on the piezoelectric body 11 are destroyed,
The performance of the piezoelectric body 11 may be deteriorated. Second,
The surface of the piezoelectric body 11 rises due to the soldering, and it is difficult to securely fix the piezoelectric body 11 to the support body 16. Thirdly, in soldering, the solder is the piezoelectric body 11
Therefore, the electrode substance may be sucked up, making it difficult to bond the two, and the performance of the piezoelectric body 11 may deteriorate. Fourth, since soldering must be performed on each of the electrodes, there is a problem in that this soldering work reduces manufacturing efficiency.

The present invention has been made in order to solve the above-mentioned problems, and the electromechanical conversion element and the drive signal supply section are provided without deteriorating the performance of the electromechanical conversion element (piezoelectric body). The purpose is to connect and.

[0008]

In order to achieve the above-mentioned object, a first solution of the ultrasonic motor according to the present invention is an electromechanical conversion element (1) excited by the supply of a drive signal.
1) and an elastic body (1) which is joined to the electromechanical conversion element and generates an oscillating wave by the excitation of the electromechanical conversion element.
2), a moving body (13) that is brought into contact with the elastic body and is frictionally driven by the vibration wave, and at least a part of an electrode of the electromechanical conversion element, and an external connection portion is the electromechanical conversion element. A conductive plate (21) arranged outside the
A driving signal supply unit (22), which is connected to the external connection unit of the conductive plate and supplies a driving signal to an electrode of the electromechanical conversion element.

A second solving means is the same as the first solving means, wherein the conductive plates (21a to 21c) are each composed of a plurality of conductive plates joined to respective electrodes of the electromechanical conversion element. The conductive plate is provided so as to cover substantially the entire surface of each electrode of the electromechanical conversion element. A third solving means is characterized in that, in the second solving means, the plurality of conductive plates are joined to a surface side of the electromechanical conversion element with a large number of electrode divisions. According to a fourth solution means, in the first solution means, the conductive plates (21e to 21g) are each composed of a plurality of conductive plates joined to respective electrodes of the electromechanical conversion element. Is joined to a part of the electrode of the electromechanical conversion element in the vicinity of the external connection portion.

[0010]

In the solution of the present invention, the electromechanical conversion element and the drive signal supply section are connected via the conductive plate without directly heating the electrode section of the electromechanical conversion element.
Therefore, there is no possibility that the electrode portion of the electromechanical conversion element will be destroyed, and since swelling due to solder does not occur, it can be securely fixed to the support. Further, in the second solving means, since the conductive plate is bonded to substantially the entire surface of the electromechanical conversion element, the conductive plate can be bonded more reliably. In the third solving means, since the conductive plate is bonded to the surface of the electromechanical conversion element with many electrode divisions, it is possible to bond the smoother surface side of the electromechanical conversion element and the elastic body. . In the fourth solution, since the conductive plate is joined to a part of the electrode of the electromechanical conversion element,
The vibration of the electromechanical conversion element is no longer constrained.

[0011]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is an external perspective view showing the configuration of a first embodiment of an ultrasonic motor according to the present invention. Also,
FIG. 2 is a side view of FIG. In the following, in the embodiment of the present invention, the same parts as those of the conventional example are designated by the same reference numerals, and the duplicated description will be omitted. In the ultrasonic motor 20 of FIG.
A conductive plate 21 (21a to 21d) is attached to the surface of the piezoelectric body 11 opposite to the contact surface side with the elastic body 12. The conductive plate 21 is formed of, for example, a copper plate having a thickness of about 0.05 mm. The conductive plate 21 is attached so that at least a part thereof protrudes to the outside of the outer periphery of the piezoelectric body 11, and this part is connected to the drive signal supply units 22a to 22d that supply a drive signal to the electrodes of the piezoelectric body 11. There is. This connection is made by soldering.

FIG. 3 is a plan view showing a state where the piezoelectric body 11 and the conductive plate 21 are joined. The conductive plate 21 is composed of four conductive plates 21a to 21d. These conductive plates 21 are formed on the surface of the piezoelectric body 11 with a small electrode division (see FIG.
It is joined to the surface) side. Therefore, the surface (the surface shown in FIG. 8) of the piezoelectric body 11 with many electrode divisions is joined to the elastic body 12. These conductive plates 21a to 21d are joined so as to cover substantially the entire regions of the A-phase electrode portion 11a, the B-phase electrode portion 11b, the pickup portion 11c, and the GND portion 11d of FIG. 7, respectively.

As a method of joining the conductive plate 21 to each electrode of the piezoelectric body 11, for example, there is a method of adhesion. In the embodiment, first, the drive signal supply portions 22a to 22d are soldered to the conductive plates 21a to 21d, and the conductive plates 21a to 21d are connected to the piezoelectric body 11 so that the solder portions face the elastic body 12 side.
Glued to. As the adhesive, an epoxy adhesive 377 manufactured by Epolak Co., Ltd. was used.
The state of 0 ° C. was maintained for 2 hours.

FIG. 4 shows each electrode portion 11a-1 of the piezoelectric body 11.
1c, the conductive plate 21, and an adhesive 25 for bonding them
It is a figure which shows the interface state with (the shaded part in a figure). Each of the electrode portions 11a to 11c is formed of silver paste or the like, and the surface thereof is not smooth but has large irregularities. Therefore, even when the respective electrode portions 11a to 11c and the conductive plate 21 are connected by the adhesive 25, the two are not completely insulated, but at least a part thereof is in contact with each other. As a result, even if the two are adhered by the adhesive 25, electrical continuity can be obtained.

As described above, each electrode portion 1 of the piezoelectric body 11
If the driving signal supply unit 22 is joined to the electrodes 1a to 11c, the electrode unit 11a of the piezoelectric body 11 is soldered as in the conventional case.
Since ~ 11c is not heated, the performance of the piezoelectric body 11 does not deteriorate. Moreover, since the surface of the piezoelectric body 11 does not rise due to soldering, the piezoelectric body 11 can be reliably fixed to the support body 16.

Next, a second embodiment will be described. The second embodiment has the same configuration as that of the first embodiment, but the conductive plates 21a to 21d are bonded to the surface (the surface shown in FIG. 8) of the piezoelectric body 11 where the electrode division is large, and the piezoelectric plate The body 11 is joined to the elastic body 12 on the side (the surface shown in FIG. 7) where the electrodes are less divided. The method of joining the conductive plates 21a to 21d and the piezoelectric body 11 is the same as that of the first embodiment. As described above, the surface of the piezoelectric body 11 where the electrodes are divided is divided into the A-phase electrode portion 11a and the B-phase electrode portion 11b at a pitch of λ / 2, respectively. Part 1
When soldering the drive signal supply unit 22 to 1b, it must be done for each one. However, as in the second embodiment, the A-phase electrode portion 11a and the B-phase electrode portion 1
Since only one conductive plate 21a and one conductive plate 21b are joined to 1b to connect the two, the manufacturing process can be significantly shortened. In addition, the elastic body 12 of the piezoelectric body 11
Since the joint surface with and is a surface with less electrode division, that is, a smoother surface, the joint strength between both can be further increased.

FIG. 5 is a diagram showing a third embodiment of the present invention and is a plan view showing a state in which the piezoelectric body 11 and the conductive plate 21 are joined. The conductive plate 21 of this embodiment is composed of four conductive plates 21e to 21h having substantially the same shape. Further, these conductive plates 21e to 21h are formed of, for example, a copper plate having a thickness of about 0.05 mm, as in the first embodiment. The conductive plates 21e to 21h are respectively provided on the surface side of the piezoelectric body 11 where the electrode division is small, the A phase electrode portion 11a, the B phase electrode portion 11b, the pickup portion 11c, G
It is joined to a part of the ND portion 11d by the same method as in the first embodiment. Then, the surface side of the piezoelectric body 11 with a large number of electrode divisions is joined to the elastic body 12. If formed in this way, the same effect as in the first embodiment can be obtained, and the vibration of the piezoelectric body 11 due to the conductive plate 21 can be restrained as much as possible.

Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment,
Various modifications are possible without departing from the spirit of the invention. For example, although the conductive plate 21 is formed of a copper plate in the embodiments, any material may be used as long as it is formed of a conductive material. Further, the bonding between the conductive plate 21 and the piezoelectric body 11 is not limited to bonding, but may be pressure bonding or the like. Further, in the piezoelectric body 11, the pickup unit 11c
Although the GND part 11d and the GND part 11d are formed apart from each other, they may be arranged side by side. If formed in this way, each of the conductive plates 21a to 21d or 21e to 21h can be efficiently connected to the drive signal supply units 22a to 22d.

[0019]

According to the ultrasonic motor of the present invention, it is possible to maintain good performance of the electromechanical conversion element without fear of breaking the electrode portion of the electromechanical conversion element. Also,
Since the swelling due to the solder does not occur, the electromechanical conversion element can be securely fixed to the support. Further, according to the second aspect, the electromechanical conversion element and the drive signal supply section can be joined more reliably. According to the third aspect, the joint strength between the electromechanical conversion element and the elastic body can be increased. Further, it is not necessary to join each of the electrode parts of the electromechanical conversion element and the drive signal supply part. According to the fourth aspect, the conductive plate and the electromechanical conversion element can be joined to each other without restraining the vibration of the electromechanical conversion element.

[Brief description of drawings]

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

FIG. 2 is a side view of FIG.

FIG. 3 is a plan view showing a state in which a piezoelectric body 11 and a conductive plate 21 are joined together.

4 is a diagram showing an interface state between the piezoelectric body 11, the conductive plate 21, and the adhesive 25. FIG.

FIG. 5 is a view showing a third embodiment of the present invention and is a plan view showing a state where the piezoelectric body 11 and the conductive plate 21 are joined.

FIG. 6 is a perspective view showing a configuration of an example of a conventional ultrasonic motor.

FIG. 7 is a plan view showing a contact surface side of the piezoelectric body 11 with the FPC.

FIG. 8 is a plan view showing a contact surface side of the piezoelectric body 11 with the elastic body 12.

[Explanation of symbols]

 11 Piezoelectric body 12 Elastic body 13 Moving body 15 Vibration absorbing material 16 Support body 20 Ultrasonic motor 21 Conductive plate 22 Drive signal supply unit

Claims (4)

[Claims] 1. An electromechanical conversion element that is excited by the supply of a drive signal, an elastic body that is joined to the electromechanical conversion element and that generates an oscillating wave by the excitation of the electromechanical conversion element, and contacts the elastic body. And a conductive plate frictionally driven by the vibration wave, a conductive plate that is joined to at least a part of the electrode of the electromechanical conversion element, and has an external connection portion arranged outside the electromechanical conversion element, An ultrasonic motor comprising: a drive signal supply unit that is connected to the external connection unit of the plate and supplies a drive signal to an electrode of the electromechanical conversion element. 2. The electroconductive plate according to claim 1, wherein the electroconductive plate includes a plurality of electroconductive plates joined to respective electrodes of the electromechanical conversion element, and the plurality of electroconductive plates respectively include the electromechanical conversion element. An ultrasonic motor characterized in that it is provided so as to cover substantially the entire surface of each electrode. 3. The ultrasonic motor according to claim 2, wherein the plurality of conductive plates are bonded to a surface side of the electromechanical conversion element with a large number of electrode divisions. 4. The conductive plate according to claim 1, wherein the conductive plate is composed of a plurality of conductive plates joined to the respective electrodes of the electromechanical conversion element, and the plurality of conductive plates are provided in the vicinity of the external connection portion. An ultrasonic motor, wherein the ultrasonic motor is joined to a part of an electrode of the electromechanical conversion element.