JP2986277B2 - Vibration wave motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to vibration using ultrasonic vibration.
Wave motor .

[0002]

2. Description of the Related Art A vibration wave motor has a basic structure including a vibrator having a piezoelectric element for generating vibration and a moving body which comes into pressure contact with the vibrator, and the vibrator is formed in a ring shape such as a circle. A type and a type formed in a rod shape or a pencil shape are mainly known, and a type using a longitudinal vibration and a torsional connector has been proposed.

[0003] The structure of a conventional bar-shaped vibration wave motor will be described with reference to FIG.

The vibrator includes piezoelectric elements 3-A, 3-B and electrode plates 2-A, 2-B between a columnar vibrating body 1 and a pressing body 4.
B, 2-G is interposed, and the vibrating body 1 is
And the pressing body 4 are fastened, and the piezoelectric element and the electrode plate are sandwiched and fixed between them.

The end surface 1-a of the vibrating body 1 is a vibrator-side friction sliding portion, and one point of the friction sliding portion vibrates in the direction of the arrow in the drawing, that is, approximately 45 ° with respect to the sliding portion. When viewed from the direction of the axis of the vibrator, it is a circular motion, and gives a rotational motion to the rotor 7 contacting the friction sliding portion 1-a and the rotor side contact portion 7-a. The constricted portion 1-b of the vibrating body 1 has a function of increasing the displacement of the friction sliding portion.

The shape of the contact spring portion 7-b of the rotor 7 is as follows.
The direction of deformation when the contact portion 7-a receives a vibrating force from the vibrating body 1 matches the vibration direction of the vibrating body 1, as shown by the arrow in the figure.
It is formed so that friction loss is reduced.

FIG. 9 is an exploded view of the vibrator of the vibration wave motor .

The directions of polarization of the piezoelectric elements 3-A and 3-B are reversed in a single piezoelectric element with the central axis as a boundary line and 3-A-a and 3-Ba.

As shown in the figure, two piezoelectric elements 3-A (hereinafter referred to as A-phase piezoelectric elements) face the same portion in the polarization direction and sandwich the electrode plate 2-A. Similarly, two piezoelectric elements 3-B (hereinafter referred to as B-phase piezoelectric elements) face the same portions in the polarization direction as shown in the figure, and
Is interposed. As shown in the figure, the two A-phase piezoelectric elements 3-A and the two B-phase piezoelectric elements 3-B are arranged to be shifted from each other by 90 ° with the electrode plate 2-G interposed therebetween.

The two A-phase piezoelectric elements 3-A and 2
Each of the B-phase piezoelectric elements 3-B has an electrode film corresponding to the polarization region on the surface facing each other, and has an electrode film formed on the entire surface on the opposite surface. Further, the electrode plate 2-G has a convex portion on the inner diameter portion, is in contact with the fastening bolt 5, and is electrically connected to the vibrating body 1 and the pressing body 4.

The electrode plate 2 of the vibrator arranged as described above
A, the 2-B, the AC voltage V _A as shown in FIG. 10, V _B
Is applied, the vibration of the A-phase piezoelectric element and the vibration of the B-phase piezoelectric element are combined to give a progressive bending mode which is a vibration like a swing. In FIG. 9 , since the vibrator 1 and the presser 4 are grounded via bolts 5 and the electrode plate 2-G (not shown), the lead wires to the vibrator 1 and the presser 4 are actually connected. It is unnecessary, and the vibrating body 1 and the pressing body 4 also serve as electrodes.

In FIG. 8 , a vibrator composed of a vibrating body 1, an electrode plate 2, a voltage element 3, a pressing body 4, and a bolt 5 is bonded and fixed to a fixing member 10 by a rotation stopper 5-a of the bolt 5. I have. Therefore, the vibrator is supported by screwing the fixing member 10 to a mounting member (not shown).

A resin spring case 6 is adhered to the rotor 7 to be integrated. The rotor 7 is rotatably supported by the shaft portion 5-c of the bolt 5 at the lower end inner diameter portion 6-a of the spring case 6,
The lower end inner diameter portion 6-a has an inner peripheral edge formed in an etch shape as shown in the figure, and the inner peripheral edge portion can be freely inclined with respect to the shaft portion 5-c of the bolt 5 with the inner peripheral edge as a fulcrum.

Reference numeral 8 denotes an output gear via a bearing 9
The bolt 5 is pivotally supported by a shaft portion 5-d. Reference numeral 11 denotes a pressure spring, which is disposed between the output gear 8 and the spring case 6 at a position shown in the figure, and presses the rotor 7 against the vibrator 1.

The output gear 8 and the rotor 7 form a detent at the portion A, and the torque of the rotor 7 is transmitted to the output gear by the portion A. In part A, the rotor 7 and the gear 8
Has a play in the radial direction and can move freely.

In the vibration wave motor having the above configuration, the electrode plates 2-A, 2-B and 2-G are not conductive.
Ku, it is important to be able to apply a reliable desired AC voltage to the piezoelectric element.

However, when the inner diameters of the electrode plates 2-A and 2-B are the same as the inner diameter of the piezoelectric element as in the prior art, the electrode plate 2-G may be removed due to conductive dust generated during the manufacturing process of the vibrator. And the electrode plate 2-A or 2-B. This will be described with reference to FIG. 11 is an enlarged view of a portion B of FIG.

FIG. 11 is a diagram schematically showing the arrangement of the piezoelectric element, the electrode plate, and the bolts in the vibrator.
The inner diameter convex portion 2G-1 of G comes into contact with the bolt 5, and the electrode plate 2-
Although the inner diameter of A is the same as the inner diameter of the piezoelectric element, the electrode plate 2-A is disposed with the inner diameter protruding because it is eccentrically provided. In such a state, the electrode plate 2
-A, 2-B, and 2-G can apply a desired AC voltage to the piezoelectric element without conducting.

[0019] However the bolt 5 during a process such as tightened to the vibrating body 1, for example, metal dust is generated from the C portion of the threads of FIG. 8, on the bumps 2-G-1 of the electrode plates 2-G When the conductive dust falls on the electrode plates 2-A and 2-G
Is conducted, and a desired AC voltage cannot be applied to the piezoelectric element.

[0029]

The problem to be solved by the present invention is that the electrodes between the piezoelectric elements constituting the vibrator and the like are electrically connected at the time of assembling and the like, and the alternating current is appropriately applied to the piezoelectric elements. The voltage cannot be applied, which may hinder the driving of the motor. An object of the invention according to the present application is to provide a vibration wave motor having a vibrator having a structure in which the electrode plates constituting the vibrator do not conduct during assembly or the like.

[0032]

Means and Actions for Solving the Problems According to the present invention,
The first configuration of the vibration wave motor that realizes the purpose of
An electro-mechanical energy conversion element having a hollow shape of a layer;
The electro-mechanical energy conversion element,
A vibrating body that vibrates in response to vibration of the energy conversion element,
A vibration wave motor having at least
Between the electro-mechanical energy conversion element of
The drive signal is applied to the electrodes of the mechanical energy conversion element.
Or a hollow electrode plate for detecting the vibration detection signal.
Sandwiching the inner diameter of the electrode plate with the electric-mechanical energy
This is larger than the inner diameter of the conversion element . Related to this application
A second configuration of the vibration wave motor that achieves the object of the present invention is as follows.
In the first configuration, the vibration wave motor may include the electric machine.
Mechanical energy conversion element and the vibrating body were brought into contact with each other
A fastening member for fastening in a state, wherein the fastening member is
Penetrating the hollow part of the gas-mechanical energy conversion element
The vibration wave motor according to claim 1, wherein: According to the present application
The third configuration of the vibration wave motor for realizing the object of the invention is as follows.
In any one of the above-mentioned structures, the electrode plate has a plurality of electric layers.
-A plurality of mechanical energy conversion elements are sandwiched between
The inner diameter of at least one of the two electrode plates
Larger than the inner diameter of the electromechanical energy conversion element
Things . Vibration waves that achieve the object of the invention according to the present application
A fourth configuration of the motor is any one of the above configurations,
-From the inner diameter of the mechanical energy conversion element to the area of the electrode
The inner diameter is increased .

According to the vibration wave motor having such a configuration,
Since the inner peripheral edge of the electrode plate is disposed so as to be recessed from the inner peripheral edge of the electro-mechanical energy conversion element, the inner peripheral portion of the vibrator may be electrically conductive dust or the like, so that the electrode plates may be placed between each other or between the electrode plate and the vibrator. It can be prevented from conducting with the structure and the fastening means.

[0036]

DETAILED DESCRIPTION FIG. 1 is a sectional view of a first embodiment of the present invention, conventional vibration wave motor and operating principle like shown in FIG. 11 are the same, function the same thing and sign of FIG. 8 Same to you. Here, only the portions different from the conventional vibration wave motor will be described.

In FIG. 1, the inner diameter of the electrode plate 2-A disposed between the A-phase piezoelectric element 3-A and the electrode plate 2-B disposed between the B-phase piezoelectric element 3-B is -A, 3
-B is formed larger than the inner diameter. For this reason, even if the electrode plates 2-A and 2-B are eccentrically arranged with respect to the piezoelectric element, they do not protrude to the bolt 5 side unlike the conventional example shown in FIG. Therefore, in the step of tightening the bolt 5 to the vibrating body 1, even if conductive dust such as screw chips is generated from the thread of the female thread portion of the vibrating body 1 shown in the portion C, for example, the electrode plate 2- A, 2-B, and 2-G can reliably apply a desired AC voltage without conducting.

The inner diameters of the vibrating body 1 and the pressing body 4 in contact with the piezoelectric element are the same as those of the electrode plates 2-A and 2-B. However, when the bolt tightening force is not so large, the piezoelectric element is cracked. If no occurrence occurs, it may be the same as the inner diameter of the piezoelectric element.

Next, FIG. 2 which is an enlarged schematic view of the portion D in FIG. 1 will be described.

The pair of A-phase piezoelectric elements 3-A and the pair of B-phase piezoelectric elements 3-B are screen-printed or vapor-deposited on both sides of piezoelectric bodies 3-A-2 and 3-B-2 such as PZT, respectively. Electrode films 3-A-1, 3-A-
3 and 3-B-1, 3-B-3. Of these electrode films, the inner diameter of the piezoelectric element (piezoelectric body 3-
Electrode plate 2 having an inner diameter larger than the inner diameter of A, 3-B).
The inner diameters of the electrode films 3-A-3 and 3-B-3 on the A and 2-B sides are the same as those of the electrode plates 2-A and 2-B and are larger than the inner diameters of the piezoelectric elements. Even if the inner diameters of the electrode films 3-A-1, 3-B-3 are the same as the inner diameter of the piezoelectric element, the thickness of the electrode film is 1
Since it is as thin as μm or less, the probability of conduction with 2-G is extremely small, but by doing so, the yield is further improved. Also, in the process of producing the electrode film of the piezoelectric element, 3-A
When it is desired to make the inner diameters of -1 and 3-A-3 and 3-B-1 and 3-B-3 the same (for example, when using the same mask), as shown in FIG. May be the same as the inner diameters of the electrode plates 2-A and 2-B.

FIG. 4 shows a second embodiment of the present invention.

In the first embodiment, the electrode plates 2-A,
Although the inner diameter of 2-B is larger than the inner diameter of the piezoelectric element, in this embodiment, the inner diameter of at least one electrode plate of the piezoelectric element is reduced, and the inner diameter of the electrode plates 2-A and 2-B is reduced. Is the same as the inner diameter of the piezoelectric element, the inner diameters of the electrode plate 2-G, the electrode portion 1-c of the vibrating body 1, and the electrode portion 4-a of the pressing body 4 are changed to the piezoelectric elements 3-A and 3-B. Larger than the inner diameter of

In this embodiment, since the electrode plate 2-G is not in contact with the bolt 5, the bolt 5 needs to be grounded via, for example, the fixing member 10.

FIG. 5 shows a third embodiment.

This embodiment has two piezoelectric elements 3-S as a vibration sensor, while the first embodiment has four piezoelectric elements. The two piezoelectric elements 3-S are the same as the piezoelectric elements 3-A and 3-B, and are arranged in an electrode plate 2 for extracting a vibration sensor signal.
The two A-phase piezoelectric elements 3-A are arranged in the same direction with respect to -S. Since the two electrode plates 2-G are in contact with the bolts 5, by grounding these electrode plates 2-G, the vibrating body 1 and the pressing body 4 are grounded, as in the first embodiment. By applying an AC voltage to the electrode plates 2-A and 2-B, the motor rotates as in the first embodiment. At this time, the piezoelectric element 3-S for the sensor generates a voltage corresponding to the vibration and detects the voltage from the electrode plate 2-S, thereby obtaining the amplitude,
Information as to whether or not the vibration is close to the resonance state can be obtained and used for controlling the motor.

In this embodiment, the inner diameter of the electrode plate 2-S is made larger than the inner diameter of the piezoelectric element in order to prevent the electrode plate 2-S from conducting to the electrode plate 2-G due to conductive dust or the like.

As described above, the present invention is effective not only in the case of the piezoelectric element for generating vibration but also in the case of having a piezoelectric element for a vibration sensor.

In each of the above embodiments, the vibration wave motor uses two orthogonal bending vibration modes. However, the present invention is not limited to this, and a hollow piezoelectric element and an electrode plate are sandwiched by bolts. Vibration mode using a vibrator
Are all valid for For example, Japanese Unexamined Patent Publication No. 62-21787
FIG. 6 shows a fourth embodiment in which the present invention is applied to a vibration wave motor using a longitudinal vibration and a torsional coupler, which is publicly known in Japanese Patent Application Publication No. No. 6 (1994). FIG. 6 is a partially cut-away side view showing the electrode plate 2-.
The inner diameter of A is made larger than the inner diameter of the piezoelectric element 3 for generating longitudinal vibration, thereby preventing the electrode plate 2-A from conducting with the other.

Since the driving method of this embodiment is known, it will not be described.

FIG. 7 shows an embodiment in which the vibration wave motor according to the present invention is used as a drive source of a film winding mechanism of a camera.

In the figure, 200 is a camera, 201 is a vibration
A driving device for the wave motor 110, a transmission device 202,
Denotes a film winding spool.

The oscillating wave motor is driven by the drive 20 in a known manner.
The output is transmitted to a film winding spool 203 by a transmission device 202, and the rotation of the film winding device winds a film (not shown).

[0072]

According to the present invention, the inner peripheral edge of the electrode plate is disposed so as to be recessed from the inner peripheral edge of the electro-mechanical energy conversion element. In addition, conduction between the electrode plates or between the electrode plate and the structure of the vibrator or the fastening means can be prevented, so that a desired drive signal can be reliably applied or a vibration detection signal can be output.

[Brief description of the drawings]

FIG. 1 is a sectional view of a vibration wave motor according to a first embodiment of the present invention.

FIG. 2 is an enlarged sectional view showing a portion D in FIG. 1;

FIG. 3 is an enlarged sectional view showing a modification of the first embodiment of FIG. 1;

FIG. 4 is a sectional view of a vibration wave motor according to a second embodiment.

FIG. 5 is a sectional view of a vibration wave motor according to a third embodiment.

FIG. 6 is a sectional view of a vibration wave motor according to a fourth embodiment.

FIG. 7 is a diagram showing an embodiment in which the vibration wave motor of the present invention is used as a drive source of a film winding mechanism of a camera.

FIG. 8 is a sectional view showing a conventional vibration wave motor .

FIG. 9 is an exploded perspective view of the vibrator of FIG. 8 ;

FIG. 10 is a waveform diagram of an AC voltage applied to the vibration wave motor .

FIG. 11 is an enlarged sectional view of a portion B in FIG. 8 ;

[Explanation of symbols]

1: Vibrating body 2-A, 2-B,
2-G: Electrode plate 3-A, 3-B: Piezoelectric element 4: Holder 5: Bolt 6: Spring case 7, 31: Moving body 8: Gear 9: Bearing 10: Fixed member 11: Spring 32: Main body 33 ... Flange part 34 ... Tip part 35 ... Contact surface

Claims (4)

(57) [Claims] An electro-mechanical energy having a plurality of hollow shapes.
Conversion element and the electro-mechanical energy conversion element.
Receiving the vibration of the electro-mechanical energy conversion element
A vibrating body having at least a vibrating body.
Between the plurality of electro-mechanical energy conversion elements,
The drive signal is applied to the electrodes of the electromechanical energy conversion element.
Hollow shape for signal application or vibration detection signal detection
And the inner diameter of the electrode plate is adjusted by the electro-mechanical
The feature is that it is larger than the inner diameter of the energy conversion element
Vibration wave motor . 2. The vibration wave motor according to claim 1 , wherein
A state in which the energy conversion element is in contact with the vibrator.
A fastening member to be fastened with the electric member.
It penetrates the hollow part of the mechanical energy conversion element
The vibration wave motor according to claim 1, wherein 3. The multi-layer electro-mechanical device according to claim 1 , wherein
Multiple sheets are sandwiched between energy conversion elements and are adjacent in the axial direction.
The inner diameter of at least one of the two contacting electrode plates is
-That the inner diameter of the mechanical energy
The vibration wave motor according to claim 1 or 2, wherein: 4. An electro-mechanical energy conversion element according to claim 1, wherein
Characterized in that the inner diameter of the area of the electrode is larger than the diameter.
The vibration wave motor according to claim 1, 2 or 3, wherein