JPS63110973A - Piezoelectric driver - 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 composed of an oscillator 2 having a square shape in cross section formed into a quadrilateral body of piezoelectric material, and said oscillator 2 is equipped with a piezoelectric element part 4 having electrodes 8a-8b and bas an oscillator 1 for resonant oscillation, a power unit 5 and a contact member 6. Thus, a given high frequency voltage with a phase difference (90 degrees) from the power unit 5 is applied to respective piezoelectric element parts 41-44 of the oscillating body 2 for excitation, respective opposed sides 3 oscillate in longitudinal and lateral directions, respectively. As a result, the tip part of the oscillator 1 moves circularly or elliptically and the contact member 6 moves linearly in the direction of the arrow P as shown in the drawing.

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.

[Foreground 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.

Further, as another conventional example, there is one shown in Japanese Unexamined Patent Publication No. 58-148682. 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. 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.

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]

In this invention, the vibrator and the contact member reliably contact each other at the position of maximum vibration amplitude to obtain stable driving force, thereby achieving high efficiency with low power consumption, and less variation in characteristics.
It is an object of the present invention to provide a piezoelectric drive device with 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 elements with a phase difference; a contact member that contacts one side of each opposing side of the vibrator; and at least one of the contact member and the vibrator. A protrusion is provided near the maximum amplitude part of the vibrator and serves as a contact part between the contact member and the vibrator, and the maximum amplitude part of the opposite side of the vibrator moves in a circle or an ellipse. Accordingly, either the contact member or the vibrator is driven.

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 in the shape of a mouth or a mouth, the opposite sides thereof 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.

In addition, since a protrusion is provided on at least one of the contact member and the vibrator, which is located near the maximum amplitude part of the vibrator and becomes a contact area with each other, it is not affected by the surface precision of the vibrator or the contact member. , the vibrator and the contact member can reliably come into contact near the maximum amplitude portion, and from this, very high efficiency can be obtained.

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 mouth 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; a contact member 6 that is brought into contact with each side of the opposite side 3 of the vibrator 1; The maximum amplitude part of the opposing side 3 of the vibrator 1 moves in a circular or elliptical manner.
Either the contact member 6 or the vibrator 1 is driven. The protrusion 6a may be the contact member 6 itself, or may be another member attached to it.The maximum amplitude part of the opposing side 3 is the longitudinal center of the opposing side 3 when vibrating in the first mode. Become.

The vibrating body 2 is made of a piezoelectric material such as PZT (lead zirconium titanate porcelain), but a composite material of a piezoelectric material and plastic may also be used. 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 the base 7 as shown in FIG.

The contact member 6 is supported by guide means (not shown) so that it can move forward and backward relative to the base 7 in the direction of arrow P in FIG.

As shown in FIG. 1, the electrodes 8a and 8b of each piezoelectric element portion 4 (41 to 44) are interdigitated. In other words, the opposite side 3
A plurality of unit electrodes al and b1 are arranged in the longitudinal direction perpendicular to the longitudinal direction of the unit electrodes aI and b1, and every other unit electrode aI and bI are connected to each other at the connecting portions a2. Two sets of electrodes 3a, 8 connected by b2
form b. This piezoelectric element section 4 performs polarization treatment by applying a DC voltage between these 2 m long electrodes 8a and 8b.
It utilizes the piezoelectric longitudinal effect of the next mode.

The power supply device 5 includes high frequency power supplies 5a and 9 as shown in FIG.
0" phase shifter 9, each piezoelectric element part 4 (4X~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 to the piezoelectric element portions 41 to 44 on the two opposing sides 3 of the motion vibrating body 2 by the power supply device 5 shown in FIG. vibrates in the longitudinal and transverse directions according to the excitation of 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 opposite side of the vibrator 1
The X and Y points at the tip of the robot move in a circular or elliptical orbit as shown in FIG. Therefore, if the contact member 6 is arranged so as to be in contact with one surface of the opposing side 3, the contact member e
Move linearly in the direction of 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 the magnitude of the voltage applied to each piezoelectric element part 4, - 44.
It can be adjusted by adjusting the phase difference, etc.

If a voltage with a 90° advance phase 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 manner, since each vibrating body 2 is in the shape of an opening, the opposing 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 3a 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 the two opposing sides 3 are continuous.
Since the vibration is carried out in a non-vibrating state as shown in FIG. 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 vibrations of both sides act additively to produce a driving force, thereby increasing the number of contact points. Therefore, wear is reduced and stable driving is possible.

Further, since the contact member 6 is provided with the protrusion 6a, the opposing side 3 and the contact member 6 are reliably brought into contact near the maximum amplitude portion. Therefore, a large propulsion force is obtained, resulting in high efficiency.

In this embodiment, the opposite side 3 is 1s as shown in FIG. 5(A).
Although we have explained the case of vibration in t mode, Fig. 5 (
B), as shown in (C), 2nd mode and 3rd mode
By vibrating in a higher-order mode such as mode, the number of contact points of the opposing side 3 with the contact member 6 can be further increased. This makes it possible to further reduce wear at the contact points and stabilize the operation.

When vibrating in a higher-order mode such as 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 the adjacent divided 4 poles are reversed. In addition, when vibrating in a higher order mode, the protrusion 6 of the contact member 6
a is arranged at all the maximum amplitude parts in each mode. That is, in the first mode, n protrusions 6a are provided.

In the above embodiment, the protrusion 6a has a circular arc cross-sectional shape, but the protrusion 6a may have a convex cross-sectional shape other than a circular arc, as shown in FIGS. 6(A) and 6(B). It is also possible to have a rectangular cross-sectional shape as in the second embodiment.
B) is a contact member 6 used when vibrating in a secondary mode.

Furthermore, in this embodiment, the vibrator 1 is brought into contact with only one side of the contact member 6, but as in the third embodiment shown in FIG. You may let them. In this case, the protrusion 6a of the contact member 6
Provided on both sides. 8 is a spacer that connects the two vibrating bodies 2;

FIG. 8 shows a fourth embodiment. In this example, a protrusion 3a is provided on the vibrator 1 side. The protrusion 3a may be the vibrator 1 itself or another member. The contact member 6 may be provided with a protrusion 6a as shown in FIG. 1, or may be provided without a protrusion 6a. May be used.

FIG. 9 shows a fifth embodiment, in which the contact member 6' is connected to the support shaft 10.
It is a rotating type that can be rotated freely around the body. The contact member 6' is provided with an annular protrusion 6a' corresponding to the maximum amplitude part of the vibrator 1. The vibrator 1 is similar to the example shown in FIG. 1 or FIG.

FIG. 10 shows a sixth embodiment, in which the vibrator 1' consists of one U-shaped vibrating body 2'. The contact member 6 has a protrusion 6a and can move forward and backward in the direction of arrow P.

Electrodes 8a and 8b are provided in the form of interdigitated fingers on the opposing sides 3'.

Figure 1) shows a seventh embodiment, in which the vibrator 1' is U-shaped and the contact member 6' is of a rotary type that can freely rotate around the support shaft 10. The contact member 6' has an annular projection 6a'.

Each of the embodiments shown in FIGS. 7 to 1) provides advantages similar to those of the first embodiment.

FIG. 12 and FIG. 13 show the eighth and ninth embodiments, respectively. In the example of FIG. 12, two adjacent sides of the opposite side 203
A piezoelectric element portion 204 utilizing a piezoelectric transverse effect is formed on the surface. 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 C3d along the longitudinal direction of the opposing side 203. This electrode C
Polarization treatment is performed by applying a DC voltage for 1 d. + in the figure,
- indicates the polarity of polarization.
, d, the opposing side 203 expands and contracts due to the piezoelectric transverse effect of the piezoelectric element portion 204, causing bending vibration.Other structural functions are the same as in the first embodiment.

The example shown in FIG. 13 is an embodiment in which the vibrator 201' utilizes the second-order vibration mode of one Kujiaki vibrating body 202', and the vibrator 201' uses the second-order vibration mode of one Kujiaki 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 pair of electrodes e, f and the second and second electrodes e, f are polarized with opposite polarity and a high frequency voltage of the same phase is applied, or the polarization is in the same direction and a high frequency voltage of opposite polarity is applied. Apply.

〔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 is U-shaped or square-shaped, 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.

In addition, since a protrusion is provided on at least one of the contact member and the vibrator, which is located near the maximum amplitude part of the vibrator and becomes a contact area with each other, it is not affected by the surface precision of the vibrator or the contact member. , the vibrator and the contact member can reliably come into contact near the maximum amplitude portion, and this has the effect that very high efficiency can be obtained.

[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 a block diagram of its power supply device, Fig. 4 is an explanatory diagram of its operation, and Fig. 5 is its vibration mode. Explanatory drawings, FIGS. 6A and 6B are perspective views of the contact member of the second embodiment, FIG. 7 is a cutaway side view of the third embodiment, and FIG. 8 is a fourth embodiment. Fig. 9 is a plan view of the fifth embodiment, Fig. 10 is a perspective view of the sixth embodiment, Fig. 1) is a plan view of the seventh embodiment, Fig. 12 and the 13th
The figures are perspective views of vibrators in eighth and ninth embodiments, respectively. 1.1'... vibrator, 2.2'... vibrating body, 3...
・Opposite side, 4.4□~4. ...Piezoelectric element part, 6.6'
...Contact member, 6a, 6a'...Protrusion, 8a, 8b
... Electrode, 201, 201' ... Vibrator, 202.
202'... Vibrating body, 203, 203'... Opposing side Patent applicant Hiroshi Shimizu (Figure 1, Figure 3, Figure 2 a, Figure 4, Figure 5, CB) Figure 6, Figure 7, Figure 13

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; a contact member that contacts one side of each opposing side of the vibrator; and an amplitude of the vibrator that is applied to at least one of the contact member and the vibrator. a protrusion provided near a maximum part and serving as a contact part between the contact member and the vibrator, and the maximum amplitude part of the opposite side of the vibrator moves in a circular or elliptical manner, so that the A piezoelectric drive device in which either a contact member or a vibrator is driven. (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.