JPS62147975A - Piezoelectric motor - Google Patents

Abstract

PURPOSE:To efficiently obtain rotation in one direction and in the opposite direction with a simple organization, by combining the first piezoelectric element in the shape of a conical truncated and inverted cone, with a second piezoelectric elements fixed on a driving piece extended in the radial direction of a first piezoelectric element. CONSTITUTION:A piezoelectric motor is provided with a first piezoelectric element 12 in the shape of a conical truncated cone. On an outer peripheral section in the radial direction of a first piezoelectric element 12, a base end section is fixed, and a driving piece 13 extended in the radial direction of the first piezoelectric element 12. On the driving piece 13, a second piezoelectric elements 29a-29d extended in the radial direction of the first piezoelectric element 12 are fixed. On the one side in the thickness direction of the first piezoelectric element 12, a rotary body butted to the driving piece 13 is set. By applying mutual-phase-shifted voltage to the first and second piezoelectric elements 12, 29a-29d, the rotary body is rotated in the one direction or in the other direction.

Description

TECHNICAL FIELD The present invention relates to a piezoelectric motor in which a piezoelectric element is energized to generate vibration and the vibration is used to obtain rotational torque.

PRIOR ART @FIG. 7 is a plan view showing the -55 minute configuration of the piezoelectric motor 1 of the prior art, and FIG. 8 is a front view of FIG. 7. 7th
The structure and operation of the prior art piezoelectric motor 1 will be described with reference to FIG. 8 and FIG.

A piezoelectric motor 1 includes a piezoelectric element 2 in which electrodes are formed on a piezoelectric body.
A vibration transmission member 3 is fixed to one surface of the . On the opposite side of the piezoelectric element 2 from the vibration transmission member 3, a lil handle member 4 made of an elastic material such as rubber is arranged.

Furi I! A plurality of protrusions 5 a, 5 b, 5 c, and 5 d (generally referred to as reference numeral 5 when necessary) are formed in the circumferential direction on the opposite side of the IJ transmission member 3 from the piezoelectric element 2. As shown in FIGS. 7 and 8, each of these projections 5 is configured to be inclined in a certain direction along the circumferential direction of the vibration transmission member 3, for example. The tips of each protrusion 5 G a, 6 b
, 6 c + 6 d (collectively referred to by the reference numeral 6 when necessary), for example, a disc-shaped circuit 1 μ member 7
is placed. As will be described later, this rotating member 7 is rotated to extract driving force as a piezoelectric motor.

The operation will be described below. Arrow A of piezoelectric element 'T-2
The displacement in one direction is transmitted by the vibration transmission member 3, that is, the surface of the vibration transmission member 3 on the rotating member 7 side is displaced to the state shown by imaginary #1171 in FIG. At this time, since the rotating member 7 is supported by a structure not shown so as not to be displaced in the negative direction in FIG. ,
On the other hand, its tip 6 abuts against a rotating member 7 . Therefore, each protrusion 5 is a virtual line in the IP8 diagram! As shown by 2, it is bent in the direction of inclination, and at this time, the rotating member 7 is rotated in the same direction.

On the other hand, the retraction displacement of the piezoelectric element 2 in the direction of arrow A2 displaces the vibration transmission member 3 to the position shown by the solid line in FIG. Return to the position indicated by the solid line in the figure. By repeating such operations, the rotating member 7 can be rotationally driven in the direction of arrow A3.

In such a piezoelectric motor 1 of the prior art, the rotation of the rotating member 7 is only in the direction of inclination of the protrusion 5 of the vibration transmitting member 3, that is, in the direction of arrow A3. Therefore, the rotation taken out from the rotating member 7 is in one direction. It cannot be used for applications that require bidirectional rotation in the pond direction.) and (m points).

The eighth object of the present invention is to solve the problems mentioned above, to simplify the structure, and to provide an improved structure in which the rotating body can be rotated with high efficiency in both the one force direction J3 and the opposite direction. An object of the present invention is to provide a piezoelectric motor.

Embodiment FIG. 1 is a sectional view of a piezoelectric motor 10 according to an embodiment of the present invention, and FIG. 2 is a sectional view of a vibration transmission member 11 and a first piezoelectric element 1.
2, and FIG. 3 is an exploded perspective view of the piezoelectric motor 10 of FIG. 1. The configuration and operation of the piezoelectric motor 10 of this embodiment will be explained with reference to FIGS. 1 to 3. FIG.

In the piezoelectric motor 10 of this embodiment, for example, PZT
A piezoelectric body 12 made of a piezoelectric ceramic material such as
An inverted truncated cone-shaped piezoelectric element 12 having electrodes 12b and 42c formed on both surfaces in the thickness direction of a is surrounded from the circumferential direction, and is made of a rigid material such as iron, for example, and the piezoelectric element 2 For example, a ring-shaped vibration transmission member 11 is fixed, which transmits the vibration from one surface to the Ikegata surface without absorbing it.

The vibration transmission member 11 has an inner circumferential surface 11a having a shape into which the piezoelectric element 12 is fitted and fixed. A protrusion 14a is provided on the outer circumference 13 of the vibration transmission member 11, and is a drive piece that protrudes outward in the radial direction and is inclined in a certain direction along the circumferential direction.
, 14 b, 14 c, and 14 d (collectively referred to by the reference numeral 14 when necessary) are provided in a protruding manner. In the vibration transmission member 11 , a mounting annular portion 1111 that is a portion excluding the protrusion 14 constitutes a base end portion of the protrusion 14 .

On one surface of the vibration transmission member 11 in the thickness direction, an annular rotating body T-15 is arranged. The rotor 15 is coaxially equipped with a rotating shaft 16, and is locked to a sleeve support 2 () consisting of an inner ring 17, an outer ring 18, and a rotary shaft 19.

A housing ring 21 that accommodates the entire structure connected to the cylinder is disposed, and between the piezoelectric element 12 and the bottom plate 22 of the housing ring 21, the piezoelectric element 12 is made of an elastic material such as rubber. A buffer member 23 capable of absorbing vibrations in the directions of arrows Bl and B2 (expansion/contraction displacement along the vertical direction in FIG. 1) is arranged, and the piezoelectric element 12 and the bottom plate 22 are each made of an elastic material such as silicone rubber. It is fixed with an adhesive or the like.

f:tS2 piezoelectric elements 29a, 29b, 29 are provided on the common side portions of the protrusions 14a to 14d along the circumferential direction.
e, 29d (collectively referred to by reference numeral 29 when necessary)
is fixed to X1. These two second piezoelectric elements have rectangular piezoelectric bodies 213a, 2Gb, 26c, 2Gd, and have electric currents ff127a, 28a: 2711.28+l
; 27c+28c: 27d and 28cl are formed, respectively, and utilize the radial displacement of the vibration 1 transmission member 11.

FIG. 4 is a block diagram illustrating the electrical configuration for driving the piezoelectric motor 10 of this embodiment. From the oscillator 21],
For example, a sinusoidal voltage is generated, amplified via line 30 by amplifier 'a31, and applied to piezoelectric element 2. Also, the sinusoidal voltage from the oscillator 29 is connected to the line 30.
The voltage is applied to a phase shifter 33 via a branch line 32 that branches off from the line 30, and advances the phase of the voltage on the line 30 by, for example, 90 degrees.

The output of the phase shifter 33 is amplified by the amplifier 34 and commonly given to the second piezoelectric elements P 29 a to 29 d. Opposite sides of the piezoelectric element 12 and the two V second piezoelectric elements a to 29d are commonly grounded. That is, fpJ
A common phase voltage is applied to the two piezoelectric elements P29a to 29d.

FIG. 5 is a waveform diagram illustrating the phase of the voltage that drives the piezoelectric motor 10 of this embodiment. The line in Figure 5! 1 indicates the output voltage v1 of the amplifier 31, and line 12 indicates the output voltage v1 of the amplifier 34.
The output voltage ■2 is shown. The voltage v2 has a phase lead of 90 degrees compared to the voltage ■1. That is, the output voltage Vl, V
2 can generally be expressed by the following formula.

V1=VOsinωL ・(1)V
2=VOsin(ωt-i/'2) =(2)
vO; amplitude ω; angular frequency fj'; Figure G shows the protrusion 11b of the piezoelectric motor 10 of this embodiment.
It is a diagram showing the operating state of 'Jl. The operation of this embodiment will be described with reference to FIGS. 1 to 6.

In Pt5G diagram (1), the voltage ■1 is not applied to the first piezoelectric element 12, and the voltage ■2 of negative polarity, for example, is applied to the second piezoelectric element 29b at time t=to in FIG.
(t=o). At this time, the second piezoelectric element 29b undergoes a degenerate change 1-r, for example. 1 will be cultivated. f:tS2 Due to the degenerate displacement of the piezoelectric element 29b,
Protrusion 14bli arrow rfA1 direction 1: Ta h mi, bent from the state shown by the two-dot chain line in FIG. 5(1) to the state shown by the solid line. At this time, the lower end surface 25 of the protrusion 141 which is the end surface on the rotor 15 side may be configured to be separated from the lower end surface 24 which is the end surface of the rotor 15 on the protrusion 141+ side.

FIG. 6(2) shows the case at time L1 in FIG. 5, where the maximum voltage at the applied jM voltage ff=V1, that is, V1=VO, is applied, and no voltage is applied to the second piezoelectric element 29b. do not have. At this time, the first piezoelectric element 12 is configured to be elongated and displaced, for example.

The first piezoelectric element 12 is formed into an inverted truncated cone shape, as described above. Therefore, the radial displacement P1 on the electrode 12b side, which has a larger diameter, is larger than the displacement lP2 on the electrode 12c side, which has a smaller diameter.

That is, the vibration transmission member 11 is given the above-mentioned different radial displacement amounts Pi and P2, and the protrusion 14b is displaced toward the buffer member 23 side (arrow A3 side) as it goes from the inside to the outside in the radial direction. This means that That is, the protrusion 14b is displaced to the position shown by the solid line in FIG. 6(2), and the protrusion 14b is separated from the lower end surface 2, t of the rotor 15.

Figure 6 (3) is the case of L2 at 11.7 in Figure 5,
While the voltage 1 is suppressed, the second piezoelectric element 2
91] is the maximum voltage ■0.

Therefore, the second piezoelectric element 291] is extended and displaced, and the protrusions 1 and 11) are bent in the direction of arrow A2, which is the opposite direction to the direction of arrow Δ1.

No. G (71(4) is the case at time L3 in FIG. A retraction displacement is applied which is opposite to the elongation displacement of the displacement amounts Pi and P2.

The second degenerate displacement includes a return from the elongation displacement to the state when no voltage is applied, and a degenerate displacement from the state when no voltage is applied. Therefore, the protrusion 14b of the vibration transmission member 11 is displaced in the direction of arrow A4, which is opposite to the direction of arrow A3, and the rotor 1
5 comes into contact with the lower end surface 24 of 5. At this time, the protrusion 14b performs an elliptical motion as shown by the arrow B1 in FIG.
Provides frictional force in two directions.

That is, the upper end surface 25 b of the protrusion 1411 as described above
The motion of a point in disinω[(d
l; amplitude) longitudinal vibration and d2sin (ωL-π
/ 2 Hd2: Amplitude) Such a combined vibration with a transverse vibration generally follows an elliptical orbit shown by the arrow B1 in the n3 diagram, and when di = d2,
Displaced along the virtual circumference. The operation described above for the protrusion 1411 is applied to each of the remaining protrusions 14a, 14c, 14t.
1-], it is performed synchronously. Therefore, due to such a synthetic vibration displacement, the rotor 5 is driven to rotate in the direction of the arrow B5! r! IJ is done.

As described above, the rotation T-15 is rotationally driven in the force direction of arrow B1 in FIG. On the other hand, the piezoelectric motor 10 of this embodiment can also rotate in the direction of arrow B2, which is the opposite force direction to the rotation in the direction of arrow B1. In other words, the line in Figure 16! 3, a voltage with a phase delayed by 90° from the phase of the voltage V1 applied to the first piezoelectric element T-12 is applied to each second piezoelectric element T-12.
It may be applied to the piezoelectric element 253.

In the above-described embodiment, the second piezoelectric element 29 was provided on one common side of the protrusion 14, but it may be provided on the other side in the circumferential direction or on both sides. At this time, the fifth
The polarity of the piezoelectric material forming each piezoelectric element may be selected so that bidirectional rotation in the direction of arrow B1 or the direction of arrow B1 described with reference to FIG. 6 and FIG. 6 is possible. Further, the phase shift of the driving voltages in the above embodiment is not limited to 90°, and the number of protrusions 14 is not limited to four. Further, the first piezoelectric element 12 has the protrusions 14a, 14b,
14c and 14d may be directly fixed.

At this time, the protrusion 14! The 1″-radial inner circumferential surface has a shape that corresponds to the shape of the first piezoelectric element 12 having an inverted truncated cone shape.

Effects As described in (2) above, the piezoelectric motor according to the present invention includes a truncated conical first piezoelectric element. A base end portion is fixed to the radially outer peripheral portion of the f:tS1 piezoelectric element, and a driving piece extending in the radial direction of the first piezoelectric element is provided. This drive piece has a first
A second piezoelectric element extending in the radial direction of the piezoelectric element is fixed. Further, a rotating body that comes into contact with the drive piece is provided on one side in the thickness direction of the first piezoelectric element. Voltages out of phase with each other were applied to the first and second piezoelectric elements.

At this time, by advancing or delaying the phase of the voltage applied to the first piezoelectric element and the second piezoelectric element in a predetermined manner, the rotating body is rotated in one direction and in the opposite direction, respectively.
r can. In this way, bidirectional and highly efficient rotation can be obtained by the piezoelectric motor having a simple configuration.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a piezoelectric motor 10 according to an embodiment of the present invention.
f:trJ2 Figure is a plan view of the first piezoelectric element T-12 and the vibration transmission member 11, Figure 3 is an exploded perspective view of the piezoelectric motor 10, Figure 3 is a perspective view of the vibration transmission member 11, and Figure 4 is the piezoelectric element T-12 and the vibration transmission member 11. 5 is a waveform diagram illustrating the drive voltage to the piezoelectric motor 10, FIG. 6 is a diagram illustrating the operating state of the protrusion 141J, and FIG. 7 is a diagram illustrating the operating state of the protrusion 141J. 310...Piezoelectric motor, 11...Vibration arm member, 12...First piezoelectric element, 14...Protrusion,
15... Rotor, 24... Lower end surface, 25... Upper end surface, two... Second piezoelectric element, 20... Oscillator, 33...
Insertion of phase shifter substitution Patent Dispersion Upper Part Figure 1 Figure 2 Figure 3 Figure 4 Figure 4 70 80 Procedural Correction Power March 1986 r! q Patent Application No. 30-288117 2. Name of the invention Piezoelectric motor 3. Relationship with the case of the person making the amendment Applicant address name (583) Matsushita Electric Works Co., Ltd. Representative 4, Agent address 1-13 Nishihonmachi, Nishi-ku, Osaka No. 33 Tokosan Building Country 11% [EX 0525-5985 rN
TAIFT, J International FAX GI[I&GI[(0
6) 538-02476, Detailed description of the invention column of the specification to be amended and Drawing 7, Contents of the amendment (1) In the 9th line of page 5 of the specification tjS [and tilted in a certain direction along the circumferential direction] Delete the text "Shi". (2) In the specification fjS page 6, 131st to 14th lines, 1 protrusion 24 side surface J is replaced with "protrusion 14 side surface"
Correct. (3) In the 8th line of page 8 of the specification, ``voltage V2J'' is corrected to ``voltage VOJ.'' (4) In the specification; 1, 10th line, 12th line, ``arrow B2
"Direction" should be corrected to "Arrow B5 direction." (5) Statement! @Page 10, lines 13 to 14, "upper end surface 25b" is corrected to (upper end surface 25). (6) Ming #3 book f: ts page 11, lines 4 to 5 1] and in the 6th line, ``1 arrow B1 direction'' is corrected to 1 arrow B3 direction.'' (7) In the specification 1!F, page 11, line 7 (), 1 arrow B
The text "2 directions" should be corrected to "arrow B4 direction." (8) In the 8th line of page 11 of the specification, "Fig. 6" is corrected to "Fig. 5." (9) Figures 1, 3, and 6 of the drawings will be corrected as shown in the attached sheet. Above Figure 1 Figure 3 Procedural Amendment (Method) April 2, 1986 1, 1, ``Bl Cow Display Conker 1 Kyo 60 2 f 18117, ``. 2. Name of the invention Piezoelectric motor 3. Relationship with the 55 amendments Name of applicant 1 (583) Matsushita Electric Works Co., Ltd. Representative A 4, Agent 15 Address 13 J-chome, Nishihonmachi, Nishi-ku, Osaka No. 38 Shinko R'L Building Kokusai Equipment EX 0525-5985 IN
TAPT J International FAX GIIl & GI [(06)
538-112476, Column 7 of the brief explanation of the drawings in the specification subject to amendment, line 11 of the specification of contents of the amendment fjIJ13T1, ``Figure 10 is corrected to ``Figure 7''. that's all

Claims (1)

[Scope of Claims] A first piezoelectric element having an inverted truncated cone shape; a drive piece having a base end fixed to the radial outer circumference of the first piezoelectric element and extending in the radial direction of the first piezoelectric element; a second piezoelectric element that extends in the radial direction of the element and is fixed to the drive piece; and a rotating body that abuts the drive piece on one side in the thickness direction of the first piezoelectric element; A piezoelectric motor is characterized in that voltages that are out of phase with each other are applied.