JPS63294278A - Piezoelectric driving device - Google Patents

Abstract

PURPOSE:To efficiently convert oscillation to a mechanical driving force, by providing square or U-shaped oscillating unit and by permitting both the confronted sides to resonate together. CONSTITUTION:A piezoelectric driving device is formed of a U-shaped metallic elastic material, and is of one oscillating unit 2 with the respectively square cross sections of a pair of confronted sides 3, and on two surfaces of the respectively adjacent confronted sides 3, piezoelectric elements 3 are fitted to form piezoelectric element sections 4. When specified high-frequency voltage is applied to the element sections 4, then the confronted sides 3 are provided with a bending-oscillating oscillator 1, the power-supply device 5 of said high-frequency voltage, a permanent magnet 7, and the driving member 6 of a magnetic unit, and the driving member 6 or the oscillator 1 is driven. As a result, the resonance of the oscillating unit 2 is performed so that the base end section 2a of the two continuous confronted sides 3 may be in a non-oscillation state, and so from supporting the base end section 2a, oscillation is not to be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a piezoelectric drive device, such as a reciprocating type or a rotary type, using a piezoelectric element.

[Background technology]

Conventionally, as an ultrasonic morph using a piezoelectric element,
There is one shown in Publication No. 9-037672.

This involves attaching a piezoelectric element to a vibrating body to generate longitudinal vibration, forming a tilted drive piece at the tip of the vibrating body, and causing the tip to move in an ellipse due to the longitudinal vibration, and connecting it to a disk. Upon contact, the disc is rotated by frictional force.

However, with this conventional structure, the direction of rotation is determined by the direction of inclination of the drive piece, and the tip of the drive piece is thin, so wear is large due to friction, and there are problems in terms of service life.

Another conventional example is disclosed in Japanese Patent Application Laid-open No. 148682/1982. In this example, the entire vibration of the piezoelectric element is transmitted to the vibrating body, and one waveform is 99 times larger than the other waveform.
By vibrating with a 0° phase shift, a traveling wave is generated on the surface of the vibrating body, and by bringing the rotor into contact with the traveling wave, the rotor is rotated by friction.

According to this example, reversal is possible, but it is necessary to always apply energy to the entire vibrator, and moreover, it is necessary to absorb vibrations on the surface of the piezoelectric element opposite to the surface attached to the vibrating body. Therefore, energy loss is large and it is difficult to improve efficiency. In addition, in forming a linear motor, unless a measure is taken to circulate the traveling waves, the energy loss is too large to be a problem, and the circulation method is also extremely difficult.

In addition, all of these conventional structures are driven using friction, which poses problems in terms of service life and generation of abrasion powder.

[Purpose of the invention]

An object of the present invention is to provide a piezoelectric drive device that can efficiently obtain mechanical driving force with low power consumption, has no contact points, has a long life, and can be driven stably.

[Disclosure of the invention]

The piezoelectric drive device of the present invention includes at least one vibrating body formed of an elastic material into a mouth shape or a mouth shape, and whose cross-sectional shape of a pair of opposing sides is approximately rectangular,
Furthermore, the vibrating body is configured to vibrate at least two adjacent sides of each of the opposing sides.
A vibrator having a piezoelectric element part on a surface, a predetermined high frequency voltage is applied to the piezoelectric element part, and the opposing sides resonate by bending vibration; and a phase difference between adjacent piezoelectric element parts on each of the opposing sides. a power supply device that applies a high frequency voltage with a maximum amplitude portion of the opposite side of the vibrator; Either the opposing side of the driving member and at least a part of the opposing portion are made of a permanent magnet, and the other is made of a magnetic material, and the maximum amplitude point of the opposing side of the vibrator moves in a circular or elliptical manner. , either the driving member or the vibrator is driven.

The piezoelectric element portion may be formed by adhering a piezoelectric element to the vibrating body, or may be formed by forming the vibrating body from a piezoelectric material and forming electrodes directly on this piezoelectric material. There may be.

According to the configuration of the present invention, a high frequency voltage with a phase difference is applied to the piezoelectric element portions provided on two adjacent sides of each opposing side of each vibrating body, so that the maximum amplitude point of each opposing side is a circle or an ellipse. exercise. Either the driving member or the vibrator is driven by the change in magnetic flux between one of the opposing sides and the driving member, and a mechanical driving force is obtained.

In this case, since each vibrating body is U-shaped or square-shaped, the opposing sides resonate with each other, and a large amplitude can be obtained. Therefore, electrical energy can be efficiently converted into mechanical driving force. In addition, since the resonance of the vibrating body occurs in a non-vibrating state at the base end where the two opposing sides are continuous, by using the base end as the support part, the vibration is not hindered by the support. , this also provides high efficiency. Furthermore, since there are parts of the vibrating body that do not vibrate, either the vibrator or the driving member can be used as either a fixed side or a movable side. Further, the vibrating body has two opposing sides, and since the magnetic flux changes at these parts, there are many driving points, and since there is no contact, there is no wear, and stable driving is possible.

Embodiment A first embodiment of the present invention will be described with reference to FIGS. 1 to 5. This piezoelectric drive device is an example applied to a linear motor, and consists of one vibrating body 2 made of a metal elastic material in a U-shape and having a pair of opposing sides 3 each having a rectangular cross-sectional shape. In the vibrating body 2, a piezoelectric element portion 4 is formed by pasting piezoelectric elements on two adjacent sides of each of the opposing sides 3,
When a predetermined high-frequency voltage is applied to this piezoelectric element part 4, the opposite side 3 resonates by bending vibration. The power supply bag W5 to be applied and each one of each opposing side 3 of the vibrator 1
It is equipped with a permanent magnet 7 provided at the tip of the surface and a driving member 6 made of a magnetic material that faces the permanent magnet 7 at a constant interval, and the maximum amplitude point of the opposing side 3 of the vibrator 1 is a circle or an ellipse. In some cases, either the drive member 6 or the vibrator 1 is driven by movement.

The vibrating body 2 is made of a constant elastic body such as Erinba, but if accuracy or large amplitude is not required, a general steel material may be used.
Further, other metals, ceramics, etc. can also be used. If the vibrating body 2 is a magnetic material, the amount of change in magnetic flux is large and the driving efficiency is improved.

The cross-sectional shape of each opposing side 3 of the vibrating body 2 is rectangular, but each corner may be chamfered to have an octagonal cross-sectional shape.
Also, the corners may be rounded instead of chamfered. In short, the opposing sides 3 only need to have a cross-sectional shape having four sides adjacent to each other at right angles. The base end 2a of the vibrating body 2 has a length that does not affect vibration even if it is fixed, and is fixed to a base 21 as shown in FIG. 2.

The drive member 6 is moved relative to the base 21 in the direction of the arrow P in FIG.
It is supported by guide means (not shown) so that it can move forward and backward in the directions. The driving member 6 is located at a point X and a point Y (
4(B)) and are arranged at a constant interval G (FIG. 2).

The power supply device 5 includes high frequency power supplies 8 and 90 as shown in FIG.
A voltage is applied to each piezoelectric element portion 4 (4□ to 44) as shown in the figure.

The + and - signs in the figure indicate the polarization direction.

When a high frequency voltage is applied to the piezoelectric element portions 4, - 44 on the two opposing sides 3 of the motion vibrating body 2 by the power supply device 5 shown in FIG. , ~44 vibrate in the longitudinal and transverse directions according to the excitation. At this time, the piezoelectric element parts 42 and 44 have piezoelectric element parts 4. ．． 90° than 48
When a voltage with a delayed phase is applied, the opposite side 3 of the vibrator 1
The X point and the Y point at the tip move in a circular or elliptical orbit as shown in FIG. 4(C). Therefore, if the driving member 6 is arranged on one surface of the permanent magnet 7 on the opposing side 3 at a constant interval G, the driving member 6 moves linearly in the direction of the arrow P. The flatness of the elliptical orbits of the X point and the Y point is determined by the difference in bending rigidity depending on the bending direction of the opposing sides 3 and by the difference in the bending rigidity of each piezoelectric element portion 41 to 44
The magnitude of the voltage applied to can be adjusted by adjusting the phase difference or the like.

Piezoelectric element portions 42, 4. If a voltage with a phase advanced by 90° is applied to the drive member 6, the drive member 6 will move in the opposite direction to the arrow P, drawing a trajectory opposite to that shown in FIG. 4(C).

Although it operates in this way, since each vibrating body 2 is in the shape of an opening, the opposite sides 3 of the vibrating bodies 2 resonate with each other, and a large amplitude is obtained. Therefore, electrical energy can be efficiently converted into mechanical driving force. In addition, since the resonance of the vibrating body 2 is performed in a non-vibrating state as shown in FIG. 3 at the base end 2a where the opposing sides 3 of the two trees are continuous, it is necessary to use the base end 2a as a support part. Therefore, vibrations are not hindered by the support, and high efficiency can be obtained from this as well. Further, since there are parts of the vibrating body 2 that do not vibrate in this way, either the vibrator 1 or the driving member 6 can be used as either a fixed side or a movable side.

In this way, since the vibrating body 2 is caused to resonate in a non-contact manner, it can be used with a large amplitude, and since it is driven in a non-contact manner, there is no wear and has a long life.

In addition, in the first embodiment shown in FIGS. 1 to 5,
A permanent magnet 7 is provided on the side of the vibrator 1 and the driving member 6 is made of a magnetic material, but conversely, the driving member 6 is made of a permanent magnet and the vibrator
may simply be a magnetic material.

Note that the magnetic body includes a permanent magnet, and both the drive member 6 and the vibrator 1 may be made of permanent magnets.

In each of the embodiments described below in FIG. 6, either the driving member or the vibrator may be a permanent magnet.

In short, either one of the maximum amplitude portion of the opposing side of the vibrating body and at least a portion of the portion of the driving member facing the opposing side may be a permanent magnet, and the other may be a magnetic material.

FIG. 6 shows an embodiment in which a vibrator 1 consisting of one mouth-shaped vibrator 2 is used as a rotary motor.

The drive member 16 is formed into a disk shape, and its shaft 18 is connected to a bearing 19.
It is rotatably supported on a base 17. The vibrator 1 made of a magnetic material is fixed to a vertical piece of a base 17 at its base end 2a. The two opposing sides 3 of the vibrator 1 are arranged in parallel with a driving member 16 made of a permanent magnet at a constant interval, and their tips are located at the outer periphery of the driving member 16. Then, the two wooden vibrators 3 are vibrated to perform circular motion in the same direction, and the drive member 16 is rotated. The rest is the same as the first embodiment.

FIGS. 7 and 8 show two vibrating bodies 2 made of mouth-shaped magnetic bodies arranged in a superimposed manner with an interval between them, and a driving member 6' made of a permanent magnet between the upper and lower vibrating bodies 2. are arranged at regular intervals.

The upper and lower vibrating bodies 2 are stacked on top of each other at their base ends 2a with a spacer (not shown) interposed therebetween. Note that each vibrating body 2 may be individually attached to a base (not shown) without using a spacer. Each point m, n, p, q on the opposite side 3 of the re-vibrating body 2 is
The drive member 6' is vibrated by the piezoelectric element 4 as shown in FIG. 8, and driven in a straight line by circular or elliptical motion of each opposing side 3 on both upper and lower surfaces. In this case, since the two vibrating bodies 2 are used for driving, an even larger driving force can be obtained, and the operation can be stabilized. The rest is the same as the first embodiment. The re-vibrating body 2 may be integrated with each other at the base end 2a' as shown in FIG. 9 to form one vibrator 1'.

FIG. 10 shows an example in which an integral H-shaped vibrator 1'' is constructed with two mouth-shaped vibrating bodies 2 facing oppositely to each other. use That is, a shaft 31 is fixed to the center of a vibrator 1'' made of a magnetic material, the shaft 31 is fixed to a base 37, and a drive member 36 made of a disc-shaped permanent magnet with a bearing 38 mounted is attached to the shaft 31. The tips of the four opposing sides 3 are connected to the drive member 3 so that it can rotate freely.
6 at a constant interval. The drive member 36 is bent by each piezoelectric element portion 4 so that the tips of the opposing sides 3 of the four trees move circularly in the same direction.
rotates, forming a rotary motor. The rest is the same as the first embodiment.

FIGS. 12 to 14 show one mouth-shaped vibrating body 10.
An example using a vibrating body 101 consisting of two parts will be shown. In this example, when the vibration is in the first mode, the point at the center of the opposing side 103 moves in a circle or an ellipse, and when the drive member 106 is opposed to the plane part with a constant interval, the center point moves in a circle or an ellipse. The elliptical motion causes the drive member 106 to move.

The drive member 106 can also be supported directly in the direction of arrow Q so as to be movable back and forth to form a linear motor.
6 can also be rotatably supported to form a rotary motor. In this example, the vibration in the first mode is as shown in FIG. 14. 107 is a base. The method of polarizing the piezoelectric element portion 4 is the same as described above. Other structural effects are the same as in the first embodiment.

FIGS. 15 and 16 show two vibrating bodies 102 made of magnetic material in the shape of a mouth, arranged in a superposed manner with a spacer 105 in between, and a permanent magnet placed between both vibrating bodies 102 with a constant distance between them. A driving member 106 is arranged so as to be movable linearly in the direction of arrow Q. The piezoelectric element portion 4 is attached to the opposite side 103 of the four-piece tree so as to move as shown in FIG. The rest is the same as the first embodiment.

In each of the above embodiments, the piezoelectric element portion 4 was attached only to two adjacent sides of the opposing sides 3.103, but the piezoelectric element portion 4 may be attached to the third side or the fourth side. .

17 to 19 show vibrators 401 to 401, respectively.
'' is formed of a piezoelectric material, and the piezoelectric element portions 404 to 4 are directly connected to each other.
04'' is shown.As the piezoelectric material,
A piezoelectric ceramic such as PZT (lead zirconium titanate porcelain) or a composite piezoelectric material of a piezoelectric ceramic and a plus deck is used.

Although these piezoelectric materials do not have magnetism, they may be made of a mixture of plastic and magnetic materials mixed with piezoelectric ceramics to give the entire vibrator 401 to 401'' the characteristics of a magnetic material. .

Moreover, instead of mixing magnetic materials, the vibrators 401 to 4
01'' as described later may be formed of a magnetic material to give the vibrators 401 to 401'' the effect of a magnetic material.

In the example shown in FIG. 17, the vibrator 4.01 is composed of one U-shaped vibrating body 402, and the opposite side 403 has a rectangular cross section.
A piezoelectric element portion 404 that utilizes the longitudinal effect of the first-order mode is directly formed on two adjacent surfaces. Each piezoelectric element section 404 has a plurality of electrodes a1. b1 are arranged in the longitudinal direction, and every other electrode a4. I) 1 to connecting part a2. They are connected at b2 to form two sets of electrodes Ha and b. That is, electrode a
1. bl is provided in a cross-finger shape in the lateral direction. A DC voltage is applied between these two electrode sets a and b to perform polarization processing.

+ and - in the figure indicate polarization.

If polarization is performed in this way and a high frequency voltage is applied by a power supply device similar to the power supply device 5 in FIG.
The piezoelectric element portion 404 expands and contracts mainly due to the piezoelectric longitudinal effect, causing bending vibration. In addition, two adjacent sides of the opposite side 403
When a voltage having a phase difference is applied to the piezoelectric element portion 404 on the surface, the tip of the opposing side 403 performs circular or elliptical motion. Note that the electrodes a1. of each piezoelectric element portion 404. Only two pieces of b1 may be used.

In the example shown in FIG. 18, piezoelectric element portions 404' utilizing a piezoelectric transverse effect are formed on two adjacent sides of opposing sides 403'. In this example, the electrodes c and d are arranged in a vertically interdigitated manner. That is, each piezoelectric element portion 404' forms an interdigital electrode consisting of two or many parallel electrodes c and d along the longitudinal direction of the opposing side 403'. A DC voltage is applied between the electrodes c and d to perform polarization treatment. →− and − in the figure indicate the polarity of polarization. When a high frequency voltage is applied between the electrodes c and d after polarization in this manner, the opposing side 403' expands and contracts due to the piezoelectric transverse effect of the piezoelectric element portion 404', causing bending vibration. Other structural functions are similar to the embodiment shown in FIG. 17.

The example in FIG. 19 is an embodiment in which the vibrator 401'' utilizes the second-order bending mode of one mouth-shaped vibrating body 402''.
Two piezoelectric element portions 404'' utilizing a piezoelectric transverse effect are formed on each of two adjacent sides of each opposing side 403''. That is, two parallel electrodes e and f are provided along the longitudinal direction on opposite sides 403'' on both sides of the central part in the longitudinal direction, and two parallel electrodes are set as one set, and direct current is applied between these two electrodes. Polarization is performed by applying a voltage.At this time, the first set of electrodes e, f and the second set of electrodes e, f are polarized with opposite polarity, and a high-frequency voltage of the same phase is applied, or the polarization is performed. High frequency voltages of opposite polarity are applied in the same direction.

These vibrators 401 to 401 in FIGS. 17 to 19
A reciprocating type or rotary type piezoelectric drive device is constructed by combining the drive member 6, 36, etc. with the drive member 6, 36, etc. in the same manner as in each of the embodiments described above.

Similarly to the examples shown in FIGS. 17 to 19, even in cases where the vibrator is composed of a plurality of vibrating bodies as in the examples shown in FIGS. 9, 10, and 15, the vibrator is piezoelectric. It is also possible to form the electrode directly by forming the material.

Also, as in the case of pasting, the opposite sides 403 to 403"
It is also possible to provide piezoelectric element portions 404 to 404'' on three or four sides.

In this way, by directly forming the piezoelectric element portions 404-404'' on the vibrators 401-401'' by using a piezoelectric material such as piezoelectric ceramic for the vibrators 401-401'', it is possible to omit pasting the piezoelectric elements. Since there is no adhesive layer, performance can be stabilized.In addition, unlike pasting piezoelectric elements, there is no variation in characteristics due to errors in pasting, and productivity is improved by reducing man-hours.Moreover, the shape The piezoelectric drive device of the present invention allows each vibrating body to be shaped like a mouthpiece or a piezoelectric drive device that is advantageous in terms of cost and performance. Since the two opposing sides resonate with each other, a large amplitude can be obtained.Therefore, electrical energy can be efficiently converted into mechanical driving force.Furthermore, the resonance of the vibrating body is caused by the resonance of the two opposing sides. is performed in a non-vibrating state at the continuous proximal end, so by using the proximal end as a support part, the vibration is not hindered by the support (this also provides high efficiency. Since there are parts of the vibrating body that do not vibrate as described above, either the vibrator or the driving member can be used as a fixed side or a movable side.

Furthermore, since the vibrating body resonates in a free state without contact with the driving member, a large amplitude can be obtained. Moreover, since it is a non-contact drive, there is no wear, resulting in a long life and stable drive.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of an embodiment of the present invention, FIG. 2 is a cutaway side view thereof, FIG. 3 is an explanatory diagram of the vibration mode, and FIG. 4(A) is a plan view of the vibrator. Figure 4 (B)
4(C) is a diagram explaining its operation, FIG. 5 is a block diagram of the power supply device, and FIG.
Figures (A) and (B) are a plan view and a cutaway side view of yet another embodiment, respectively, Figure 7 (A) is a plane view of yet another embodiment, and Figure 7 (B) is a front view thereof; FIG. 8 is an explanatory diagram of its operation, FIG. 9 is a perspective view of a vibrator of still another embodiment, FIG. 10 is a perspective view of a vibrator of still another embodiment,
11(A) and 11(B) are respectively a broken plan view and a longitudinal side view of the whole, FIG. 12 is a perspective view of still another embodiment, FIG. 13 is a broken side view thereof, and FIG. 14 is the same. 15 is a perspective view of a vibrator according to another embodiment, FIG. 16 is a perspective view of the entire vibrator, and FIG. 17 is an explanatory diagram of its vibration mode.
The 19th figure is a perspective view of a vibrator in yet another embodiment different from each other. ], I', 1'', 101 401~401''... vibrator, 2,102,402.402', 402''...
Vibrating body, 3,103,303.303', 303''・
... Opposite side, 4, 4, ~44.404,404'. 404''...Piezoelectric element portion, 6.6', 16,106°206.306...Driving member, 7...Permanent magnet patent applicant 'Hiroshi Shimizu 1) Opening E-2942''/8 ( 7) Darkness 11 Kaihi r (63-294278 (8) Figure 15 Ko O3 Figure 19

Claims (11)

[Claims] (1) At least one vibrating body is formed of an elastic material into a U-shape or a C-shape, and each of a pair of opposing sides has a substantially rectangular cross-sectional shape; a vibrator having a piezoelectric element portion on at least two adjacent sides thereof, and a predetermined high frequency voltage is applied to the piezoelectric element portion so that the opposing sides resonate by bending vibration; a power supply device that applies a high-frequency voltage to a piezoelectric element portion with a phase difference; and a drive member that faces each of the opposing sides of the vibrator with a constant distance therebetween, Either one of the maximum amplitude part of the side and at least a part of the part facing the opposite side of the drive member is a permanent magnet, and the other is a magnetic material, and the maximum amplitude point of the opposite side of the vibrator is a circle or A piezoelectric drive device in which either the drive member or the vibrator is driven by performing an elliptical motion. (2) The piezoelectric drive device according to claim 1, wherein the piezoelectric element section is formed by adhering a piezoelectric element to the vibrating body. (3) The piezoelectric drive device according to claim 1, wherein the vibrating body is made of piezoelectric ceramic, and the piezoelectric element portion has a driving electrode formed directly on the piezoelectric ceramic. (4) The piezoelectric drive device according to claim (2) or (3), wherein the vibrator includes one vibrating body. (5) The piezoelectric drive device according to claim (2) or (3), wherein the vibrator includes two vibrating bodies. (6) The two vibrating bodies are disposed in a superimposed manner with a predetermined spacing between them, and the driving member faces two pairs of opposing sides of the vibrating body with a constant spacing therebetween. Range number (
5) The piezoelectric drive device described in item 5). (7) The two vibrating bodies each have a U-shape and are arranged in an H shape, and the driving member maintains a constant distance from the two pairs of opposing sides of the vibrating body. A piezoelectric drive device according to claim (5), which is opposed to the above. (8) The piezoelectric drive according to claim (2) or (3), wherein the drive member is formed into a flat plate shape, and either the drive member or the vibrator is linearly driven. Device. (9) The piezoelectric actuator according to claim (2) or (3), wherein the driving member is formed into a disk shape, and either the driving member or the vibrator is rotationally driven. Drive device. (10) The piezoelectric drive device according to any one of claims (1) to (9), wherein the vibrating body is made of a magnetic material. (11) The piezoelectric drive device according to claim (10), wherein the drive member is a permanent magnet.