JP2924385B2 - Ultrasonic motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic motor using an elastic vibration excited by a piezoelectric body as a driving force, and more particularly to a mounting position of a lead wire of the piezoelectric body and a support structure of the ultrasonic motor .

[0002]

2. Description of the Related Art In recent years, an ultrasonic motor that excites a vibrating body made of a piezoelectric body such as a piezoelectric ceramic and uses the vibrating body as a driving force has drawn attention. Hereinafter, a conventional ultrasonic motor will be described with reference to the drawings. FIG. 6 is a perspective view of an ultrasonic motor, and a vibrating body 3 is formed by bonding a piezoelectric body 2 to one surface of an elastic substrate 1. On the other surface of the elastic substrate 1, a projection 1a is provided. Reference numeral 4 denotes an elastic body, and reference numeral 5 denotes a wear-resistant friction material. The moving body 6 is in pressure contact with the vibrating body 3 via the friction material 5 by a spring or the like (not shown). When an electric field is applied to the piezoelectric body 2, a traveling wave of bending vibration is excited in the circumferential direction of the vibrating body 3, and the moving body 6 is driven by a frictional force. FIG. 7 shows an example of the electrode structure of the piezoelectric body 2, which is configured to excite nine bending vibrations in the circumferential direction. In the figure, A0 and B0 indicated by oblique lines are:
Each electrode group is composed of a small area corresponding to a half wavelength. C0 is an electrode having a quarter wavelength and D0 is an electrode having a length of 3/4 wavelength. The electrode group of A0 and the electrode group of B0 are mutually
Positionally has a phase difference of a quarter wavelength (= 90 degrees). The adjacent small electrode portions in the electrode groups A0 and B0 are polarized in the thickness direction opposite to each other. The bonding surface of the piezoelectric body 2 with the elastic substrate 1 is a surface opposite to the surface shown in the figure, and the electrodes are solid electrodes. In use, they are short-circuited as shown by diagonal lines in FIG. This electrode group A0, B0
Where V1 = V0sin (ωt), V2 = V0cos (ωt)
Is applied, the traveling wave of the bending vibration traveling in the circumferential direction is excited as ξ = ξ0 cos (ωt−kx).

FIG. 8 shows that a moving body 6 placed on the vibrating body 3 by applying an elliptic motion of a long axis 2w and a short axis 2u by exciting a traveling wave at a point on the surface of the vibrating body 3 is applied. , The contact is made near the vertex P of the ellipse, thereby moving at a speed V represented by V = ω × u in a direction opposite to the traveling direction of the wave due to frictional force.

[0004]

The support of the vibrating body of the ultrasonic motor having the above configuration does not hinder the vibration to be excited, and maintains the stable contact between the vibrating body and the moving body.
Vibrator in order it should be supported <br/> lifting so as to be uniform in the radial direction and the circumferential direction. Therefore, for example, the piezoelectric body side of
When supporting, it can be used for load changes in the thickness direction
In order to be able to withstand
The surface and the contact surface with the vibrating body such as the support
What is necessary is just to make it a structure. However, it is necessary to connect a lead wire or the like that supplies power to the ultrasonic motor to the piezoelectric body, in which case the surface of the piezoelectric body that is bonded to the elastic substrate is
Because a part of the opposite surface is used , the contact surface with the vibrator
Trying to support the vibrating body with a support material that is flat
However, the thickness of the lead wires and the size of
In order, there is a problem that it is difficult to stably support the vibrating body.

The present invention solves the above-mentioned problems, and devises a connection position of a lead wire and the like and a support structure to stably support a vibration body.
It is an object of the present invention to provide an ultrasonic motor in which the operation of a moving body is stable.

[0006]

To SUMMARY OF THE INVENTION To achieve this object, the ultrasonic motor of the present invention, the power supply to the two sets of drive electrodes on the piezoelectric body constituting the vibrating member of the ultrasonic motor, 2
Two sets of drive electrodes among the small electrodes constituting the set of drive electrodes
There is a row Umono from two small electrodes adjacent to the portion to make only the different phase difference wavelength of positionally 4 minutes of each other. Change
These two small electrodes are used for two sets of drive electrodes
The shape protrudes partly in the direction of the part that creates a long phase difference
Then, connect the lead wire etc. to this protruding part and
Bring the lead wires etc. close to each other and lead wires etc. in the circumferential direction of the vibrator.
The vibrating body is supported by a support
It has a structure to hold . In addition, drive electrodes are configured
The piezoelectric body and the elastic substrate on the surface on which the small electrode group
Two sets of vibrating bodies that face each other in the thickness direction
Electrodes, two sets of drive electrodes positioned quarter-wave apart from each other
Only partly in the direction of the part that creates a different phase difference
Shape and connect the lead wire etc. to this protruding part
Bring the leads etc. close to each other and lead in the circumferential direction of the vibrating body.
Vibration due to supporting material that has a recess only near the lead wire
It has a structure to support the body.

[0007]

[Action] supporting the vibrator at support or the like provided with recesses
Accordingly , the ratio of the thickness and size of the members necessary for supplying power, such as lead wires for supplying power to the two sets of drive electrodes , affecting the support state of the vibrating body is reduced .
Can be. Furthermore, the shape of the small electrode that constitutes the drive electrode
The necessary members for power supply such as the
By minimizing the recesses of the support material, etc.,
Since the contact area of the holding member and the like can be increased, the vibrating body can be stably supported.

[0008]

Embodiment 1 An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view of a first surface of a piezoelectric body of an annular ultrasonic motor, in which a primary vibration in the radial direction and a ninth order in the circumferential direction are excited in the annular vibration body. FIG. 2 is a plan view of a second surface of the piezoelectric body shown in FIG. As shown in FIG.
A small electrode corresponding to a half wavelength of the traveling wave
A drive electrode group A composed of portions a ₁ , a ₂ ,.
Drive composed of small electrode portions b ₁ , b ₂ ,...
The electrode group B is positioned so as to have a phase difference equivalent to a quarter wavelength of the traveling wave relative to each other, and an electrode C equivalent to a quarter wavelength and an electrode D equivalent to a three-quarter wavelength are arranged. It is configured. The small electrode portions a ₁ constituting the drive electrode group A ,
a ₂ ,..., small electrode portions b ₁ , which constitute the drive electrode group B ,
.., b ₂ ,..., as in the conventional example shown in FIG.
The poles are polarized opposite to each other in the thickness direction.
Is used by being electrically connected to each electrode group.
You. As shown in FIG. 2, on the second surface of the piezoelectric body 2, electrodes E and F having a phase difference equivalent to a quarter wavelength of a traveling wave excited in position relative to each other and an electrode equivalent to a quarter wavelength are provided. An electrode H corresponding to G and three-quarter wavelengths is formed.

The electrode groups A and B on the first surface correspond to the electrodes E and F on the second surface, respectively, and the electrodes C and D on the first surface correspond to the electrodes G and H on the second surface, respectively. When FIG. 2 is turned upside down and superimposed on FIG. 1, the electrode group A faces the electrode E and the electrode group B faces the electrode F. Therefore, in order to excite the traveling wave, a voltage is applied between the electrode group A and the electrode E,
At the same time, voltages having a phase difference of 90 degrees are applied between the electrode group B and the electrode F. The second surface of the piezoelectric body 2 is adhered to the elastic substrate 1, and the small electrode portions forming the electrode groups A and B are electrically connected to each other to form the vibrating body 3.

FIG. 3 is a perspective view of a vibrating body and a support member of the annular ultrasonic motor. The support member 7 is provided with a concave portion for passing a lead wire or the like connected to the piezoelectric body 2. This support
By providing a concave portion in the material 7, the piezoelectric body 2 can be connected to a lead wire or the like.
The vibrating body 3 can be supported at a place other than the connection part,
The thickness and size of the connection part such as the lead wire
The ratio affecting the holding state can be reduced. In yet <br/> Figure 1, of the small electrode portions Re that we <br/> using electrically connected to each electrode group of one wavelength equivalent to half of the traveling wave excited in the vibrating body 3, A small electrode part a ₁ adjacent to the electrode C;
Small electrode portions b ₁ adjacent to the electrode C is a portion in the direction of the respective electrodes C overhang. Make the lead wires and the like close by connecting the lead wires and the like at the protruding part
Can be can be small <br/> fence circumferential width of the recess of the support member 7 shown in FIG. As a result, the vibrating body 3 and the support
More stable because the contact area with
Thus, the vibrating body 3 can be supported. As described above, the driving electrodes and the supporting structure of the piezoelectric structure as in this embodiment, Ru can be stably supported vibrator
Therefore , an ultrasonic motor with stable operation can be realized.

[0011]

[0012]

[0013]

[0014]

According to the present invention, the piezoelectric motor and the supporting structure can stably support the ultrasonic motor by minimizing the concave portion of the member for supporting the ultrasonic motor. Can be provided.

[Brief description of the drawings]

FIG. 1 is a plan view of a first surface of a piezoelectric body of an ultrasonic motor according to an embodiment of the present invention.

FIG. 2 is a plan view of a second surface of the piezoelectric body according to the first embodiment of the present invention.

FIG. 3 is a perspective view of a vibration member and a support member of the ultrasonic motor.

FIG. 4 is a cutaway perspective view of an ultrasonic motor.

FIG. 5 is a plan view showing an electrode structure of a piezoelectric body of the ultrasonic motor.

FIG. 6 is a diagram illustrating the operation principle of an ultrasonic motor .

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Elastic board 1a Projection body 2 Piezoelectric body 3 Vibration body 4 Elastic body 5 Friction material 6 Moving body 7 Supporting material

────────────────────────────────────────────────── ─── Continuation of the front page (72) Osamu Kawasaki, inventor 1006 Kazuma Kazuma, Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) References JP-A-2-36775 (JP, A) (58) Field (Int.Cl. ⁶ , DB name) H02N 2/00

Claims (1)

(57) [Claims] 1. A piezoelectric body having two sets of drive electrodes having a positional phase difference corresponding to a quarter wavelength is driven by an AC voltage to form a vibrating body composed of the piezoelectric body and an elastic body. A connection electrode that supplies power to two sets of drive electrodes on the piezoelectric body in an ultrasonic motor that moves a movable body placed in contact with the vibrator by exciting an elastic traveling wave. Provided in a portion corresponding to a quarter wavelength adjacent to the drive electrode portion , and having a recess only in the vicinity of the connection electrode.
An ultrasonic motor which supports the vibrating body via a member .