JPH03261384A - Ultrasonic motor - Google Patents

Abstract

PURPOSE:To improve the durability of electrical coupling parts by a method wherein an elastic unit, a piezoelectric element and electrodes are held by holding members composed of first arm parts and second arm parts and the electrodes of the piezoelectric elements are electrically connected to lead wires with the first arm parts of the holding members. CONSTITUTION:Holding members 21-23 which hold electrodes 11-13 provided on the surface of a piezoelectric element 1, the piezoelectric element 1 and an elastic unit 2 from the elastic unit 2 side and the electrode 11-13 side are provided. The holding members 21-23 are composed of first arm parts 21a-23a which connect the electrodes 11-13 to lead wires 24-26 through which electric signals are inputted to or taken out of the piezoelectric element 1 and second arm parts 21b-23b which are inserted into the slits 4 of the elastic unit 2. Further, as the elastic unit 2, the piezoelectric element 1 and the electrodes 11-13 are held by the holding members 21-23 from the elastic unit 2 side and the electrode 11-13 side, the electrical coupling part can be strengthened.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to an ultrasonic motor, and in particular to an electric coupling part for inputting an electric signal to a piezoelectric element or extracting an electric signal from a piezoelectric element. between structures.

<Prior Art> As an ultrasonic motor, there is one described in Japanese Unexamined Patent Publication No. 1379/1983. - As an example, a ring-shaped ultrasonic motor is shown in FIG. 3(a). 1 is a piezoelectric element. 2
is a metal elastic body, and a large number of slits 4 are provided along the radial direction of the metal elastic body 2 on the surface of the peripheral portion 2a. A disk portion 2b is formed inside the peripheral portion 2a, and a center portion 2c is further formed inside the disk portion 2b. In addition, the peripheral portion 2a
A full-surface electrode (not shown) is installed between the surface opposite to the surface on which the slit 4 is provided and the piezoelectric element 1, and the entire surface of one side of the piezoelectric element 1 and the metal elastic body 2 are electrically connected. It is connected. The elastic metal body 2 is connected to ground at its center 2c.

That is, the entire surface of the piezoelectric element 1 on the metal elastic body 2 side is grounded via the center portion 2C of the metal elastic body 2.

54 is a rotor, and one surface of a peripheral portion 54a is brought into pressure contact with the surface of the peripheral portion 2a of the metal elastic body 2. Reference numeral 55 denotes a rotation shaft, which is integrally fixed to the center of the rotor 54. 56 is the stand of the ultrasonic motor, and the metal elastic body 2
It is fixed to the center part 2C of.

FIG. 3(b) is a diagram of the surface of the piezoelectric element 1 viewed from the stand 56 side. 11 and 12 are power supply electrodes for driving the ultrasonic motor, and 13 is a monitor electrode for detecting the vibration state of the piezoelectric element 1. Electrode 11.12.13
are arranged with predetermined gaps between them. Electrode 1
1. When 8-frequency voltages with a phase shift of 90 degrees are applied to the micrometer at 1.12, the peripheral part 2 of the elastic metal body 2 in FIG. 3(a)
A traveling wave is generated on the surface of a. This traveling wave causes the rotor 54 to rotate about the rotation shaft 55.

<Problems to be Solved by the Invention> In the above ultrasonic motor, a lead wire connected to a power supply circuit or a monitor circuit (not shown) and an electrode 11.
12.13, the electrode 11.12
．． It was conventional to solder the leads to the 13 itself - inside the shell. However, when the ultrasonic motor is driven, traveling waves are generated in the piezoelectric element 1, the metal elastic body 2, and the electrodes 11.12.13, causing the electrodes 11.12.13 to vibrate.

Therefore, as the usage time becomes longer, the electrode 11°12.1
If the solder peels off from the piezoelectric element 1 or the electrode 11.
There was a problem that 12.13 would peel off.

The present invention has been made in view of the above problems, and provides an ultrasonic motor in which the durability of the electrical connection between a piezoelectric element and an electrode, and the electrical connection between an electrode and a lead wire is improved. The purpose is to

<Means for Solving the Problems> The present invention provides a vibrating body in which the back side of an elastic body having slits on the front side and the back side of a piezoelectric element having an electrode on the front side are bonded together, and In an ultrasonic motor that has a moving body in pressure contact with the moving body and drives the moving body by generating a traveling wave on the surface of the elastic body, the ′i! It has a holding member that sandwiches the i-pole, the piezoelectric element, and the elastic body from the elastic body side and the electrode side, and the holding member inputs an electric signal to the piezoelectric element or receives an electric signal from the piezoelectric element. It is characterized by comprising a first arm part that electrically connects a lead wire from which the electrode is taken out and the electrode, and a second arm part that is inserted into the slit of the elastic body.

<Operation> According to the present invention, the second arm portion of the holding member is inserted into the slit provided in the elastic body, and the first arm portion of the holding member is inserted into the slit provided in the elastic body.
The electrodes and lead wires of the piezoelectric element are electrically connected.

Since the elastic body, the piezoelectric element, and the electrode are sandwiched between the elastic body side and the electrode side by the holding member, the electrical connection portion becomes strong.

<Example> A first embodiment device will be explained based on FIG.

FIG. 1(a) shows the star part of the ultrasonic motor according to this embodiment. 1 is a piezoelectric element. , 2 is a metal elastic body, and a large number of slits 4 are provided along the radial direction of the metal elastic body 2 on the surface of the peripheral portion 2a. A disk portion 2b is formed inside the peripheral portion 2a, and a center portion 2c is further formed inside the disk portion 2b. Further, a full-surface electrode (not shown) is installed between the surface of the peripheral portion 2a opposite to the surface where the slit 4 is provided and the piezoelectric element 1, and the metal elastic body 2 are electrically connected. The elastic metal body 2 is connected to ground at its center 2c. That is, the entire surface of the piezoelectric element 1 on the metal elastic body 2 side is
The metal elastic body 2 is grounded through its center 2G. A rotor (not shown) is brought into pressure contact with the surface of the peripheral portion 2a of the metal elastic body 2. Moreover, the center part 2C of the metal elastic body 2
is fixed to a stand (not shown). The above structure is shown in Figure 3 (
This is the same as the conventional ultrasonic motor shown in a).

21, 22, and 23 are plastic snaps as holding members having the same shape. The snaps 21, 22, 23 are spaced apart from each other by 120°. 24 and 25 are lead wires connected to a power supply circuit (not shown), and 26 are lead wires connected to a monitor circuit (not shown). Lead wires 24, 25.26 are snap 21.2
2.23 metal coating parts 21c, 22c, 23c
It is soldered to (described later).

FIG. 1(b) shows a diagram of the device of FIG. 1(a) viewed from the piezoelectric element 1 side. 11 and 12 are power feeding electrodes for driving the ultrasonic motor, and 13 is a monitor electrode for detecting the vibration state of the piezoelectric element 1. Electrode 11.1
2.13 are arranged with a predetermined gap between them. Snaps 21, 22 and 23 are electrodes 11 and 12, respectively.
．． It is installed on 13. Note that the piezoelectric element 1, the metal elastic body 2, and the electrodes 11, 12, and 13 constitute a stator 3 as a vibrating body.

FIG. 1(C) is a partial sectional view showing the installed state of the snap 21. The snap 21 holds the stator 3 between two arm parts 21a and 21b, and is prevented from coming off by projections at the tips of the arm parts 21a and 21b. The arm portion 21a of the snap 21 is connected to the peripheral portion 2a1. of the metal elastic body 2. : Inserted into the provided slit 4, the arm part 21 of the 2 snaps
b is pressed against the piezoelectric element 1 via the electrode 11. Also,
A metal coating portion 21c is formed on the arm portion 21b so as to be electrically connected to the electrode 11. Lead wire 24
is soldered to the metal coating portion 21C of the snap 21. This soldering position r is approximately the middle position in the thickness direction of the elastic metal body 2, and is a position where the vibration of the stator 3 is least. Therefore, compared to the case where the lead wire is soldered directly to the electrode 11, the lead 1i24
is much less likely to peel off. Note that the arm portion 21b and the metal coating portion 21C1 solder constitute a first arm portion, and the arm portion 21a constitutes a second arm portion. In this way, the lead wire 24 and the electrode 11 are electrically connected. Moreover, since the snap 21 is made of plastic, the lead wire 24 and the metal elastic body 2 are electrically insulated by the arm portion 21a. Therefore, the front and back surfaces of the piezoelectric element 1 are insulated, and a high frequency voltage for driving an ultrahigh wave motor can be applied to the piezoelectric element 1.

Note that the snaps 22 and 23 are also installed on the stator 3 in the same manner as the snaps 21.

As described above, according to this embodiment, snap 21.22
．． 23 to sandwich the stator 3, and snap 21.2
2.23, metal coating portions 21c, 22c, 23c are placed in contact with the electrodes 11°, 12.13, respectively.
and metal coating parts 21c, 22c, 23c
Lead wires 24, 25, and 26 were soldered to. Therefore, it is possible to prevent the piezoelectric element 1 and the electrodes 11, 12, 13, or the electrodes 11, 12, 13 and the lead wires 24, 25, 26 from coming off from each other. Furthermore, since the arm portion 21a is inserted into the slit 4, the influence on the traveling waves generated on the surface of the metal elastic body 2 can be reduced. In addition, since the snaps 21, 22, 23 were placed at an interval of 120° from each other, ye to the -layer traveling wave
Can suppress blue.

Next, the snap of the second embodiment will be explained based on FIG. 2. The installation positions of the stator 3, lead wires 2425, 26, and snaps are the same as in the first embodiment, so
Here, only the snap 31 installed on the electrode 111 will be explained.

In FIG. 2, 31 is a plastic snap holding member, and has two arm portions 31a.

31b sandwich the stator 3. Further, 37 is a metal conductor, which includes a terminal portion 37a and a lead wire fixing portion 3.
Consisting of 7b. The lead wire fixing portion 37b is connected to the lead I! 2
4 is fixed to the arm portion 31b of the snap 31. Note that the arm portion 31b and the metal conductor 37 constitute a first arm portion, and the arm portion 31a constitutes a second arm portion.

The arm portion 31a of the snap 31 is connected to the peripheral portion 2a of the metal elastic body 2.
Insert it into the slit 4 provided in the. And arm portion 31
Sandwich the stator 3 between the arm portion 31b and the snap 3
Install 1. As a result, the end portion 37a of the metal conductor 37 comes into contact with the electrode 11, and the lead wire 24 and the piezoelectric element 1 are electrically connected.

In addition, since the snap 31 is made by Plus Book, the arm portion 31
The lead wire 24 and the metal elastic body 2 are electrically insulated by the lead wire a. Therefore, the front and back surfaces of the piezoelectric element 1 are insulated, and a high frequency voltage for driving the ultrasonic motor can be applied to the piezoelectric element 1.

Note that the electrodes 12, 13, . . . shown in FIG. 1(b). The lead wires 25 and 26 are also connected to the lead wires 25 and 26 by snaps and metal conductors having the same shape and material as the snaps 31 and the metal conductors 37, respectively.

As described above, according to this embodiment, the lead [134 is fixed to the arm part 31b of the snap 31 by the lead wire fixing part 37b of the metal conductor 37, and the arm part 31a of the snap 31 is inserted into the slit 4. , the arm portion 31 of the snap 31
The terminal portion 37a of the metal conductor 37 was brought into contact with the electrode 11 by sandwiching the stator 3 between the electrodes 31a and 31b. Therefore, piezoelectric element 1. The same effects as in the first embodiment can be obtained in that the electrode 11 and the lead wire 24 can be prevented from peeling off, and the influence on the traveling waves generated on the surface of the metal elastic body 20 can be reduced. Furthermore, according to this embodiment, since soldering is not performed, the lead wire 34 can be more firmly fixed to the arm portion 31b of the snap 31. As a result, it is possible to prevent the negative layer lead wire 34 and the electrode 11 from coming apart.

Note that the structure of the connection between the lead wire and the electrode is not limited to the one-wire and two-wire embodiment. That is, after attaching the lead wires to the electrodes in advance by soldering or the like, the stator and the lead wires may be sandwiched using plastic snaps or the like.

Moreover, instead of the entire surface electrode installed between the piezoelectric element 1 and the elastic body 2, the electrode group used when polarizing the piezoelectric element may be used.

<Effects of the Invention> According to the present invention, the elastic body, the piezoelectric element, and the electrode are held between the holding member having the first arm portion and the second arm portion,
The electrode of the piezoelectric element and the lead wire are electrically connected by the 11ii portion of the holding member. Therefore, the piezoelectric element, the electrode, and the lead wire can be prevented from being peeled off due to vibrations of the elastic body, piezoelectric element, and electrode, and the durability of the electrical connection portion can be improved. In other words, since the second arm is inserted into the slit of the elastic body, it is possible to reduce the effect on the traveling waves generated on the surface of the elastic body.

[Brief explanation of drawings]

FIG. 1 is a perspective view and a partial sectional view showing a first embodiment;
FIG. 2 is a partial sectional view showing a second embodiment, and FIG. 3 is a perspective view showing a conventional example. DESCRIPTION OF SYMBOLS 1... Piezoelectric element, 2... Metal elastic body, 11.12 degrees 13... Electrode, 21, 22.23... Snap. Figure 1 (a) Figure 1 (b)

Claims (1)

[Scope of Claims] A vibrating body made by bonding the surface of an elastic body with slits on the surface and the back side of a piezoelectric element with electrodes installed on the surface, and a moving body that is brought into pressure contact with the surface of the elastic body. In the ultrasonic motor that drives the moving object by generating a traveling wave on the surface of the elastic body, the electrode installed on the surface of the piezoelectric element, the piezoelectric element, and the elastic body are connected to the elastic body side and the elastic body side. It has a holding member that is held from the electrode side, and the holding member includes a first arm portion that electrically connects the electrode to a lead wire that inputs an electric signal to the piezoelectric element or extracts an electric signal from the piezoelectric element. and a second arm inserted into the slit of the elastic body.