JPS63110972A - Piezoelectric device - Google Patents

Abstract

PURPOSE:To convert a high frequency voltage into a driving force efficiently by applying said high frequency voltage with a phase difference to piezoelectric elements in two adjacent sides of respective opposed sides of each oscillator. CONSTITUTION:A piezoelectric driver is formed into a U-shaped body of piezoelectric material: composed of one oscillator 2, a pair of opposed sides 3 thereof having a square shape in cross section; equipped with a piezoelectric element part 4 having electrodes 8a, 8b formed in two adjacent sides of said opposed sides 3, an oscillator 1 for resonant oscillation, a power unit 5, and a contact member 6 by means of two plate members 6a-6b and an elastic member 6c; and drives the contact member 6 (or one of said oscillators 1). Thus, if a given high frequency voltage with a phase difference from the power unit 5 is applied to respective piezoelectric element parts 41-44 for excitation, said sides 3 oscillate in longitudinal and lateral directions and the tip part of the oscillator moves circularly (elliptically). As a result, the contact member 6 moved linearly in the direction of the arrow P.

Description

[Detailed Description of the Invention] [Technical Field] This invention relates to a reciprocating type or rotary type pressure sensor using a piezoelectric element. This relates to a drive device.

[Background technology]

Conventionally, as an ultrasonic motor using piezoelectric elements,
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 also possible, but it is necessary to always apply energy to the entire vibrator, and moreover, it is necessary to absorb vibrations to the opposite side of the piezoelectric element. Therefore, energy loss is large and it is difficult to improve efficiency. Furthermore, 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 difficult.

As a piezoelectric drive device that eliminates these conventional problems,
A mouth-shaped or mouth-shaped vibrator is formed from a metal elastic material, piezoelectric elements are pasted on two adjacent sides of a pair of opposite sides of the vibrator, and the maximum amplitude point is a circle or a circle on the opposite sides. We proposed a system that generates resonant vibration that results in elliptical motion. A contact member is brought into elastic contact with the opposing sides, so that either the contact member or the vibrator is driven.

However, since the piezoelectric element is pasted, there are large variations in characteristics, and the number of man-hours required for pasting increases, resulting in poor productivity.

[Purpose of the invention]

The object of the present invention is to provide a piezoelectric drive device that can efficiently obtain mechanical driving force with low power consumption, allows stable driving, has less variation in characteristics, and has good productivity.

[Disclosure of the invention]

The piezoelectric drive device of the present invention has at least one vibrating body formed of a piezoelectric material in a mouth shape or a mouth shape and having a pair of opposing sides each having a substantially rectangular cross-sectional shape. A piezoelectric element section is formed by forming electrodes on at least two adjacent surfaces of each opposing side, and a vibrator whose opposing sides vibrate resonantly when a predetermined high frequency voltage is applied to the piezoelectric element section; a power supply device that applies a high frequency voltage to adjacent piezoelectric element portions with a phase difference; and a power supply device that applies a high frequency voltage to adjacent piezoelectric element parts with a phase difference; A contact member in which a plate-like member is in elastic contact is provided, and either the contact member or the vibrator is driven by circular or elliptical movement of the maximum amplitude point on the opposite side of the vibrator.

According to the configuration of the present invention, a high frequency voltage with a phase difference is applied to the piezoelectric element portions on two adjacent sides of each opposing side of each vibrating body, so that the maximum amplitude point of each opposing side exhibits circular or elliptical motion. do. Since the contact member contacts one side of this opposing side,
Either the contact member or the vibrator is driven to obtain mechanical driving force.

In this case, since each vibrating body is shaped like an opening or an opening, both sides of the vibrating body resonate with each other, and a large amplitude can be obtained. Therefore, electrical energy can be efficiently converted into mechanical driving force. In addition, the vibrator is made of piezoelectric material,
Since the piezoelectric element part is constructed by forming electrodes directly on the piezoelectric material, unlike pasting the piezoelectric element, pasting has less variation in characteristics due to errors, etc., and reduces man-hours and improves productivity. .

Resonance of the vibrating body occurs in a non-vibrating state at the base end where the two opposing sides are continuous, so by using the base end as the support part, the vibration is not hindered by the support, and this This also results in high efficiency. Furthermore, since there are parts of the vibrating body that do not vibrate, either the vibrator or the contact member can be used as either a fixed side or a movable side. Further, the vibrating body has two opposing sides, both of which are in contact with the contact member, and the vibrations of both sides produce an additive vibration force, thereby increasing the number of contact points.

Therefore, wear is reduced and stable driving is possible.

Furthermore, since the contact member is made of a plurality of plate members stacked one on top of the other with an elastic member interposed in between, the contact member and the vibrator always come into contact with a substantially constant pressure even if high dimensional accuracy is not required. Therefore, there is no unevenness in the thrust force when the contact member or the vibrator moves, and it is possible to obtain a large thrust force.

Embodiment A first embodiment of the present invention will be described with reference to FIGS. 1 to 7. This piezoelectric drive device is an example applied to a linear motor, and consists of one vibrating body 2 made of piezoelectric material in a U-shape and having a pair of opposing sides 3 each having a rectangular cross section. The body 2 is the adjacent 2 of each opposing side 3.
Electrode 8a on the surface.

The piezoelectric element part 4 is configured by forming the piezoelectric element part 8b, and when a predetermined high frequency voltage is applied to the piezoelectric element part 4, the vibrator 1 whose opposing sides 3 resonantly vibrate, and the adjacent piezoelectric element part of each opposing side 3. 4
A power supply device 5 that applies a high frequency voltage with a phase difference between the two plate members 5a.

6b and an elastic member 6C interposed therebetween, the upper plate member 6a is in elastic contact with each side of the opposite side 3 of the vibrator 1, and Either the contact member 6 or the vibrator 1 is driven by the circular or elliptical movement of the maximum amplitude point of the contact member 6 or the vibrator 1.

The vibrating body 2 is made of a piezoelectric material such as PZT (lead zirconium titanate porcelain), but a composite material of piezoelectric material and plastic may also be used.The base end 2a of the vibrating body 2 does not affect vibration even if fixed. The length is not given, and it is fixed to the base 7 as shown in Fig. 2.

As shown in FIG. 1, the electrodes 8a and 8b of each piezoelectric element portion 4 (41-4.) are interdigitated. In other words, the opposite side 3
A plurality of unit electrodes aI and bI are arranged in the longitudinal direction perpendicular to the longitudinal direction of the unit electrodes aI and bI, and every other unit electrode aI and bl are connected to each other at the connecting portions a2. Two sets of electrodes 8a connected by b2
, 8b. This piezoelectric element section 4, which performs polarization by applying a DC voltage between these two sets of electrodes 8a and 8b, utilizes the longitudinal effect for the pressure 1 in the first mode.

The elastic member 6C of the contact member 6 is made of a wavy leaf spring.

Guide pins 10 are provided upright at the four corners of the lower plate member 6b as shown in FIG. 7, and the upper plate member 6a and the elastic member 6
The guide pin 10 is inserted through the guide hole 1) 12 provided in the guide hole 1). Thereby, the upper and lower plate-like members 6a, 6b and the elastic member 6C are integrated so that they are mutually movable only in the thickness direction. The contact member 6 is supported on a base 7 (FIG. 2) via guide means (not shown) so that the lower plate member 6b can move forward and backward in the direction of arrow P in FIG. It is. In addition, in FIGS. 4 and 5, the contact member 6 is shown in a simplified manner as if it were an integral part, in order to make the explanation easier to understand.

The power supply device 5 includes high frequency power supplies 5a and 9 as shown in FIG.
0@ phase shifter 9, and each piezoelectric element section 4 (4, to 44)
A voltage is applied to the electrodes 8a and 8b as shown in the figure. The + and - signs in the figure indicate the polarity of polarization.

When a high frequency voltage is applied and excited by the power supply device 5 of FIG. 6 to each piezoelectric element part 4, - 44 on two opposing sides 3 of the motion vibrating body 2, each opposing side 3 becomes piezoelectric element part 4I - 44, respectively. It vibrates in the vertical and horizontal directions according to the excitation of 44. At this time, when a voltage whose phase is delayed by 90'' than that of the piezoelectric element parts 41 and 43 is applied to the piezoelectric element parts 4□ and 44, the X point and the Y point at the tip of the opposite side 3 of the vibrator 1 are as shown in FIG. The contact member 6 moves linearly in the direction of the arrow P if the contact member 6 is arranged so as to be in contact with one surface of the opposing sides 3. X point.

The flatness of the elliptical orbit at the Y point can be adjusted by the difference in bending rigidity depending on the bending direction of the opposing sides 3, the magnitude 1 phase difference of the voltages applied to the piezoelectric elements 4, 44, etc.

If a voltage with a phase advance of 90'' is applied to the piezoelectric elements 4□, 44, the contact member 6 will move in the opposite direction to the arrow P, drawing a trajectory opposite to that shown in FIG.

Although it operates in this way, since each vibrating body 2 has a U-shape, both of its radial sides 3 resonate with each other, and large vibrations are obtained. Therefore, electrical energy can be efficiently converted into mechanical driving force.

Further, the vibrating body 2 has an electrode 8a directly on the piezoelectric material.

8b is formed and the piezoelectric element portion 4 is provided,
There is no variation in characteristics caused by pasting piezoelectric elements, and the number of man-hours is reduced, improving productivity.

The resonance of the vibrating body 2 occurs at the base end 2 where two opposing sides 3 are connected.
Since the vibration is carried out in a non-vibrating state as shown in FIG. 3(A) in a, by using the proximal end 2a as a support, the vibration is not hindered by the support, and from this, high efficiency can be achieved. can get.

Further, since there are parts of the vibrating body 2 that do not vibrate in this way, either the vibrator 1 or the contact member 6 can be used as either a fixed side or a movable side.

Further, the vibrating body 2 has two opposing sides 3, both of which are in contact with the contact member 6, and the vibration force due to the vibration of both acts additively, thereby increasing the number of contact points. Therefore, wear is reduced and stable driving is possible.

Further, the contact member 6 is composed of two plate members 6a and 6b with an elastic member 6c interposed between them, and the elastic member 6c
Since the plate member 6a is brought into elastic contact with the opposite side 3 by the restoring force, the contact pressure between the contact member 6 and the opposite side 3 is always kept substantially constant. Therefore, the unevenness of the thrust is eliminated, and it becomes possible to obtain a large thrust.

In this embodiment, the opposite side 3 is 1s as shown in Fig. 3(A).
Although we have explained the case of vibration in t mode, Fig. 3 (
B), as shown in (C), 2nd mode and 3rd mode
By vibrating in a higher order mode, the number of contact points of the opposing side 3 with the contact member 6 can be further increased. This further reduces wear at the contact points and stabilizes the operation. When vibrating in a secondary mode or a tertiary mode, for example, the electrodes 8a and 8b are divided in the longitudinal direction of the opposing sides 3, and the polarization directions of adjacent divided electrodes are reversed.

FIG. 8 shows a contact member 6' in a second embodiment. In this example, the lower plate-like member 6b' is made longer than the upper plate-like member 6a' in order to attach it to another member. A mounting hole 13 is provided in the extending portion. Oscillator 1 (Figure 1)
The upper plate member 6a' is brought into elastic contact with the upper plate member 6a'.

In each of the embodiments described above, the elastic member 6c of the contact members 6, 6' is a wavy leaf spring in which the crests of waves are arranged in the longitudinal direction of the contact members 6, 6', but as shown in FIG. A wavy leaf spring having wave crests lined up in the width direction may be used as the elastic member 6c', and as shown in FIG. 10 and FIG.
The contact member 6# may be configured by providing an elastic member 60' made of a leaf spring curved in the shape of a letter, facing inward or outward.

Further, the elastic member 6c may be made of a flat plate made of sponge or rubber, etc.
Alternatively, if the elastic member 6C is a sponge or the like, the elastic member may be bonded to the plate-like bodies 6a and 6b with an adhesive.

Furthermore, the contact members 6 to 6# may be formed by stacking three or more plate-like members and interposing an elastic member between each plate-like member.

12 to 15 show fifth to eighth embodiments, respectively. The example shown in FIG. 12 is an example in which two U-shaped vibrators 2.2 are integrated with each other at the base end portion 2aL to form one vibrator 1'. The contact member 6 is interposed between the upper and lower vibrating bodies 2.

In addition, in FIG. 12 and subsequent figures, the contact member 6 is the same as the example of FIG. 1, but is shown in a simplified manner.

The example shown in FIG. 13 is an example in which two U-shaped vibrating bodies 2 are oriented in opposite directions to form an integrated H-shaped vibrator 1''. Two contact members 6 are provided.

Both contact members 6 may be connected to each other.

In the example shown in FIG. 14, the vibrator 101 is composed of one mouth-shaped vibrating body 102. 6 is a contact member, and 103 is an opposing side.

The example shown in FIG. 15 is an example in which two mouth-shaped vibrating bodies 102 are integrated via a spacer 105 to form one vibrator lObi. The contact member 6 is interposed between the re-vibrators 102.

In each of the embodiments described above, the contact member 6 moves linearly forward and backward, but the contact member 6 may be rotatably supported.

Figures 16 and 17 show the 9th and 10th sections, respectively.
In the example shown in FIG. 16, piezoelectric element portions 204 utilizing a piezoelectric transverse effect are formed on two adjacent sides of opposing sides 203. In this example, the electrodes c and d are arranged in a vertically interdigitated manner.

That is, each piezoelectric element portion 204 forms an interdigital electrode consisting of two or many parallel electrodes 1ic, d along the longitudinal direction of the opposing side 203. A DC voltage is applied between the electrodes c and d to perform polarization treatment.

+ and - in the figure indicate the polarity of polarization. If a high frequency voltage is applied between electrodes c and d after polarization treatment in this way, the opposite side 20
3 causes expansion and contraction due to the piezoelectric transverse effect of the piezoelectric element portion 204,
The other structural functions for performing bending vibration are the same as in the first embodiment.

The example shown in FIG. 17 is an embodiment in which the vibrator 201' utilizes the second-order vibration mode of one mouth-shaped vibrating body 202', and the vibrator 201' uses the second-order vibration mode of a single mouth-shaped vibrating body 202'. Two piezoelectric element portions 204' each utilizing a piezoelectric transverse effect are formed. In other words, two parallel electrodes e and f are provided on the opposite sides 203, two of which are located on both sides of the central part in the longitudinal direction and extend along the longitudinal direction. Polarization is performed by applying a DC voltage. At this time, the first set of electrodes e, f and the second set of electrodes e, f are polarized with opposite polarities and a high frequency voltage of the same phase is applied, or the polarization is set in the same direction and a high frequency voltage of opposite polarity is applied. Apply voltage.

〔Effect of the invention〕

The piezoelectric drive device of the present invention applies a high frequency voltage with a phase difference to the piezoelectric element portions on two adjacent sides of each opposing side of each vibrating body, so that the maximum amplitude point of each opposing side moves in a circular or elliptical motion. do. Since the contact member comes into contact with one of the opposing sides, either the contact member or the vibrator is driven, and a mechanical driving force is obtained.

In this case, since each vibrating body has a mouth shape or a mouth shape, both sides of the vibrating body resonate with each other, and a large amplitude can be obtained. Therefore, electrical energy can be efficiently converted into mechanical driving force. In addition, the vibrator is made of piezoelectric material,
Since the piezoelectric element part is constructed by forming electrodes directly on the piezoelectric material, unlike pasting the piezoelectric element, pasting has less variation in characteristics due to errors, etc., and reduces man-hours and improves productivity. .

Resonance of the vibrating body occurs in a non-vibrating state at the base end where the two opposing sides are continuous, so by using the base end as the support part, the vibration will not be hindered by the support. High efficiency can also be obtained from this.Also, since there are parts of the vibrating body that do not vibrate, either the vibrator or the contact member can be used as either a fixed side or a movable side. The body has two opposing sides, both of which come into contact with the contact member, and the vibrations of both sides produce additive vibrational force, resulting in multiple contact points.

Therefore, wear is reduced and stable driving is possible.

Furthermore, since the contact member is made of a plurality of plate members stacked one on top of the other with an elastic member interposed in between, the contact member and the vibrator always come into contact with a substantially constant pressure even if high dimensional accuracy is not required. Therefore, there is an effect that the thrust force becomes uneven during the movement of the contact member or the vibrator, and it becomes possible to obtain a large thrust force.

[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 its vibration mode, and Fig. 4 (
A) and (B) are respectively a plan view and a front view of the vibrator, FIG. 5 is an explanatory diagram of its operation, FIG. 6 is a block diagram of its power supply device, and FIG. 7 is an exploded perspective view of its contact member.
FIG. 8 is a perspective view of the contact member of the second embodiment, FIG. 9 is a perspective view of a modified example of the elastic member, and FIGS. 10 and 1) are the contact members of the third and fourth embodiments, respectively. Perspective views of the members, FIGS. 12 to 17 are 5th to 10th, respectively.
FIG. 2 is a perspective view of a vibrator according to an embodiment. 1, t', t'...d oscillator, 2... vibrating body, 3...
・Opposing side, 4.41~44...Piezoelectric element part, 6~6#
...Contact member, 6a, 6b...Plate member, 6c...
・Elastic member, 8a, 8b-electrode, 101, 101'...
- Vibrator, 102... Vibrating body, 103... Opposing side,
201゜201'... vibrator, 202.202'...
・Vibration body, 203.203'... Opposite side Patent applicant Hiroshi Shimizu-1--1- ζ1) Figure 4 Figure 5 Figure 6 Figure 10 za" Figure 12 Figure 13 Figure 14 VA Figure 15 Figure 17 Procedural amendment chart (c) February 6, 1985 M61 Patent Application No. 256165 2 Title of the invention Piezoelectric drive device 3 The person making the amendment Separate η■ (Division number (A)
, (B) accession).

Claims (2)

[Claims] (1) At least one vibrating body is formed of a piezoelectric material into a U-shape or a C-shape, and each of a pair of opposing sides has a substantially square cross-sectional shape, and this vibrating body has at least one of the opposite sides. a vibrator that forms a piezoelectric element section by forming electrodes on two adjacent sides, and a predetermined high-frequency voltage is applied to the piezoelectric element section so that the opposing sides vibrate resonantly; and the adjacent piezoelectric elements on each of the opposing sides. a power supply device that applies a high-frequency voltage with a phase difference between the parts, and a plurality of plate-like members stacked on top of each other with an elastic member in between, and the plate-like members are elastically arranged on each side of the opposite sides of the vibrator. A piezoelectric drive device, comprising: a contact member in contact with the vibrator, wherein either the contact member or the vibrator is driven by a circular or elliptical motion of a maximum amplitude point on an opposite side of the vibrator. (2) The piezoelectric drive device according to claim (1), wherein the piezoelectric element portion is composed of interdigital electrodes, and the electrodes perform polarization processing and high-frequency excitation.