JPH0773428B2 - Piezoelectric drive - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a reciprocating type or rotating type piezoelectric drive device using a piezoelectric element.

[Background technology]

Conventionally, as an ultrasonic motor that uses a piezoelectric element,
There is one disclosed in Japanese Patent Publication No. 037672. This is because a piezoelectric element is attached to a vibrating body to generate vertical vibration, a driving piece having an inclination is formed at the tip of the vibrating body, and the tip makes an elliptical motion due to the longitudinal vibration, and By making contact, the disc is rotated by frictional force.

However, with this conventional structure, the rotation direction is determined by the tilt direction of the drive piece, and the tip of the drive piece is thin, and wear is large due to friction, and there is a problem in terms of life.

Further, as another conventional example, there is one disclosed in JP-A-58-148682. In this example, the entire vibration of the piezoelectric element is transmitted to the vibrating body, and one waveform is vibrated with a 90 ° phase shift from the other waveform to generate a traveling wave on the vibrating body surface, and the rotor is placed on top of it. By bringing them into contact, the rotor is rotated by friction.

According to this example, reversing is possible, but it is necessary to always apply energy to the entire vibrator, and it is also necessary to absorb the vibration of the surface of the piezoelectric element on the side opposite to the surface attached to the vibrating body. Therefore, energy loss is large, and it is difficult to improve efficiency. Further, unless a measure for circulating the traveling wave is taken to form the linear motor, the energy loss is too large to cause a problem, and the circulating method is extremely difficult.

Further, there is a device in which a plurality of piezoelectric element portions are provided on each surface of a T-shaped vibrating body so that the moving body can be driven by vibrating the vibrating body (for example, JP-A-61-15572).
No.) was not sufficient in terms of efficiency and driving stability.

[Object of the Invention]

An object of the present invention is to provide a piezoelectric drive device that can efficiently obtain a mechanical driving force with low power consumption, has multiple contact points to reduce wear, and can perform stable driving. To do.

[Disclosure of Invention]

The piezoelectric drive device of the present invention is provided with at least one vibrating body formed of a material having elasticity in a U-shape or a U-shape and each of a pair of opposing sides having a substantially rectangular cross-sectional shape.
Further, the vibrating body is at least adjacent to each of the opposite sides.
A piezoelectric element part is provided on the surface, and a predetermined high-frequency voltage is applied to the piezoelectric element part to cause the opposite side to resonate due to bending vibration, and a phase difference between the adjacent piezoelectric element parts on the opposite sides. And a contact member that is in contact with each one of the opposite sides of the vibrator, and the maximum amplitude point of the opposite side of the vibrator makes a circular or elliptical motion. As a result, either the contact member or the vibrator is driven.

The piezoelectric element portion may be formed by attaching a piezoelectric element to the vibrating body, or may be formed by forming the vibrating body with a piezoelectric material and directly forming electrodes on the piezoelectric material. It may be. When the electrodes are formed directly on the piezoelectric material to form the piezoelectric element portion, unlike the case where the piezoelectric element is attached, there is no variation in characteristics due to attachment errors or the like,
In addition, man-hours are reduced and productivity is improved.

According to the configuration of the present invention, since a high frequency voltage having a phase difference is applied to the piezoelectric element portions provided on the two adjacent surfaces of the opposing sides of each vibrating body, the maximum amplitude point of each opposing side is a circle or an ellipse. exercise. Since the contact member comes into contact with one surface of the facing side, either the contact member or the vibrator is driven,
A mechanical driving force is obtained.

In this case, since each vibrating body is U-shaped or R-shaped, both opposing sides thereof resonate with each other and a large amplitude is obtained. Therefore, electrical energy can be efficiently converted into mechanical driving force. Further, since the resonance of the vibrating body is performed so that the base end where two opposite sides are continuous is in a non-vibrating state, by using the base end as a support portion, the support does not interfere with the vibration. From this, high efficiency can be obtained. Further, since there is a portion where the vibrating body does not vibrate as described above, either the vibrator or the contact member can be used as the fixed side or the movable side. Further, since the vibrating body has two opposing sides and contacts the contact member at this portion, the number of contact points is increased. Therefore, wear is reduced and stable driving is possible.

Embodiment A first embodiment of the present invention will be described with reference to FIGS. 1 to 6. This piezoelectric drive device is an example applied to a linear motor, and is composed of a single vibrating body 2 which is formed of a metal elastic material in a U-shape and has a pair of opposed sides 3 each having a rectangular cross section. In the vibrating body 2, a piezoelectric element portion 4 is formed by adhering a piezoelectric element to the two adjacent surfaces of each of the facing sides 3.
When a predetermined high frequency voltage is applied to the piezoelectric element portion 4, the high frequency voltage is generated by providing a phase difference between the vibrator 1 in which the opposite side 3 resonates by bending vibration and the adjacent piezoelectric element portion 4 of each opposite side 3. A power supply device 5 for applying a voltage and a contact member 6 that is brought into contact with each one surface of the facing side 3 of the vibrator 1 are provided, and the maximum amplitude point of the facing side 3 of the vibrator 1 makes a circular or elliptical motion. Either the contact member 6 or the vibrator 1 is driven.

The vibrating body 2 uses a constant elastic body such as elinvar, but when precision or large amplitude is not required, general steel material may be used.
Other metals, ceramics, etc. can also be used. Although the cross-sectional shape of each opposing side 3 of the vibrating body 2 is a square,
Each corner may be chamfered to have an octagonal cross-sectional shape, or the corner may be rounded instead of chamfering. In short, the facing side 3 may have a cross-sectional shape having four surfaces that are adjacent to each other at right angles. The base end portion 2a of the vibrating body 2 has a length that does not affect vibration even when fixed, and is fixed to the base 7 as shown in FIG. The contact member 6 is movable relative to the base 7 in the direction of arrow P in FIG.
Supported by. The contact member 6 is arranged so as to be in contact with points X and Y (FIG. 4 (B)), which are the front end portions of the respective surfaces on which the piezoelectric element portions 4 of the facing side 3 are not adhered. In addition, it is not always necessary to contact the tip portion. Further, the contact member 6 may be in contact with a portion of the opposite side 3 on which the piezoelectric element portion 4 is attached, on a portion of the piezoelectric element portion 4 which is not attached. Furthermore, oscillator 1
Means that the piezoelectric element portion 4 is attached to the three or four surfaces of the pair of opposing sides 3 of the vibrating body 2, and the one surface where the piezoelectric element portion 4 of the opposing side 3 is not attached, or the piezoelectric element portion 4 is The contact member 6 may be in contact with the part of the one surface where the piezoelectric element portion 4 is not adhered. In these examples, the contact member 6 may be in contact with the surface of the opposing side 3 to which the piezoelectric element portion 4 is attached, via an insulating member.

The power supply device 5 has a high frequency power supply 8 and a 90 ° phaser 9 as shown in FIG. 6, and applies a voltage to each piezoelectric element section 4 (4 ₁ to 4 ₄ ) as shown in FIG. The + and − signs in the figure indicate the polarization directions.

Operation Piezoelectric element parts 4 ₁ to ₄ 4 on the two opposing sides 3 of the vibrating body 2 and the sixth part
When excited by applying a high frequency voltage power source device 5 of FIG., Each of the opposite sides 3 vibrates in the longitudinal and transverse directions in accordance with the excitation of each of the piezoelectric element ₄₁ to _4. At this time, the piezoelectric element parts 4 ₂ , 4 ₄
The piezoelectric element 4 ₁ to 4 ₃ when a voltage is applied which is delayed 90 ° phase than, X point of the front end portion of the opposite side 3 of the vibrator 1, Y point, such circular or elliptical Figure 5 Draw a trajectory and move.
Therefore, when the contact member 6 is arranged so as to contact one surface of the facing side 3, the contact member 6 moves linearly in the arrow P direction. The flatness of the elliptical orbit at points X and Y is 3 on the opposite side.
Bending Bending differences and rigidity due to the direction of each piezoelectric element 4 ₁
It can be adjusted by the magnitude of the voltage applied to 4 ₄ and the phase difference.

If a voltage of 90 ° lead phase is applied to the piezoelectric elements 4 ₂ and 4 ₄ ,
A trajectory opposite to that shown in FIG. 5 is drawn, and the contact member 6
Moves in the direction opposite to arrow P.

Although it operates in this way, since the respective vibrating bodies 2 are U-shaped, their opposing sides 3 resonate with each other and a large amplitude is obtained. Therefore, electrical energy can be efficiently converted into mechanical driving force. Further, the resonance of the vibrating body 2 is performed so that the base end portion 2a where the two opposing sides 3 are continuous is in the non-vibrating state as shown in FIG. 3 (A). By so doing, vibration is not hindered by the support, and high efficiency can be obtained from this as well. Further, since there is a portion where the vibrating body 2 does not vibrate in this way, either the vibrator 1 or the contact member 6 can be used as the fixed side or the movable side. Further, the vibrating body 2 has two opposing sides 3 and contacts the contact member 6 at this portion, so that the number of contact points is increased. Therefore, wear is reduced and stable driving is possible.

In this embodiment, the case where the opposite side 3 is vibrated in the primary mode as shown in FIG. 3 (A) has been described, but as shown in FIGS. 3 (B) and (C), the secondary mode or 3 When vibrating in a higher mode such as the next mode, the contact member 6 on the opposite side 3
The number of contact points with respect to can be further increased. As a result, wear at the contact point can be further reduced and the operation can be stabilized. The primary mode occurs when one piezoelectric element unit 4 is attached in the longitudinal direction of the facing side 3. The secondary mode is generated when the one piezoelectric element portion 4 is divided into two in the longitudinal direction and the polarization directions are opposite to each other. In the third-order mode, one piezoelectric element portion 4 is divided into three in the longitudinal direction, and the central divided piezoelectric element and the divided piezoelectric elements on both sides are attached so that the polarization directions are opposite to each other. Shows the amplitude mode that occurs when the same piezoelectric is applied with the same.

FIG. 7 shows an embodiment in which a vibrator 1 including one U-shaped vibration pair 2 is used as a rotary motor. The contact member 16 is formed in a disk shape, and its shaft 18 is rotatably supported by a base 17 by a bearing 19. The vibrator 1 is fixed to the standing piece of the base 17 at the base end 2a. The two opposing sides 3 of the vibrator 1 are arranged in parallel with the contact member 16 so that the tips thereof are located at the outer peripheral edge of the contact member 16. A friction piece 20 is attached to the tip of the opposite side 3, and the two vibrators 3 are vibrated so as to make circular motions in the same direction, and the contact member 16 is rotated. Others are the same as those in the first embodiment.

FIG. 8 and FIG. 9 show two U-shaped vibrators 2 which are arranged in a superposed manner with a space therebetween, and a contact member 6 ′ is arranged between the upper and lower vibrators 2. The upper and lower vibrating bodies 2 are superposed on each other at a base end portion 2a via a spacer (not shown). Each vibrating body 2 may be individually attached to a base (not shown) without using a spacer. The points m, n, p, q on the opposite sides 3 of both vibrating bodies 2 are vibrated by the piezoelectric element portion 4 as shown in FIG.
Drive straight ahead in contact with. In this case, since the two vibrating bodies 2 are used for driving, a larger output driving force can be obtained and the operation is stabilized. Others are the same as those in the first embodiment. Both vibrators 2 may be integrated with each other at the base end portion 2a 'as shown in Fig. 10 to form one vibrator 1'.

FIG. 11 shows an example in which two U-shaped vibrators 2 are oriented in mutually opposite directions to form an integral H-shaped vibrator 1 ″. This vibrator 1 ″ is, for example, as shown in FIG. To use. That is, the shaft 31 is fixed to the center of the vibrator 1 ″, and the shaft 31 is mounted on the base 37.
And the disk-shaped contact member 36 with the bearing 38 mounted on the shaft.
It is fitted in 31 so as to be rotatable, and the tip of one opposing side 3 is arranged on the contact member 36 and the outer peripheral edge. Then, each piezoelectric element 4 bends the tips of the four opposing sides 3 so as to make circular motions in the same direction, whereby the contact member 36 rotates, thereby forming a rotary motor. Others are the same as those in the first embodiment.

FIG. 13 to FIG. 15 show an embodiment using a vibrating body 101 composed of one square-shaped vibrating body 102. In this example, 1
In the case of the next mode of vibration, the point at the center of the opposite side 103 moves in a circle or an ellipse, and when the contact member 106 is brought into contact with the plane part, the contact member 106 is moved in a circle or an ellipse in the center.
106 will move. The contact member 106 may be supported linearly in the direction of the arrow Q to be a linear motor, or may be rotatably supported to be a rotary motor. In the case of this example, the vibration as shown in FIG. 15 (A) occurs in the primary mode, and the vibrations as shown in FIGS. 15 (B) and (C) occur in the secondary mode and the tertiary mode, respectively. 107 is a base. The polarization method of the piezoelectric element portion 4 is the same as described above. Other structural effects are similar to those of the first embodiment.

In FIGS. 16 and 17, two square-shaped vibrating bodies 102 are superposed on each other via a spacer 105, and a contact member 106 is linearly moved back and forth in the arrow Q direction between both vibrating bodies 102. It is arranged freely. The piezoelectric element portion 4 is attached so that the four opposite sides 103 move as shown in FIG. Others are the same as those in the first embodiment.

In addition, in the first embodiment and the embodiment of FIG.
As shown in FIG. 18, the contact member 206 may be formed into a round bar shape and positioned between the pair of opposed sides 3 (103) to be rotationally driven. Also, as shown in FIG. 19 or 20, the contact member
The 306 may be cylindrical and may be arranged so as to surround the two opposing sides 3 (103). In the example of FIG. 19, the contact member 306 is in contact with the outer surfaces of the facing sides 3 and in the example of FIG. 20, the contacting surfaces of the pair of facing sides 3 are in the same plane. In this case as well, the contact member 3 (103) makes a rotary motion.

Further, in each of the above-described embodiments, the piezoelectric element portions 4 are attached only to the two adjacent surfaces of the facing sides 3 and 103, but the piezoelectric element portions 4 may be attached to the three surfaces or may be attached to the four surfaces. When it is attached to three surfaces, it is desirable to contact the contact members 6, 6 ', 106 with the remaining one surface. When it is attached to four surfaces, it is desirable that the opposing side 3 and the contact members 6, 6 ', 106 are brought into contact with each other via an insulating member. Insulation member is contact member 6,
It may be provided on the 6 ', 106 side or on the opposite side 3 side.

21 to 23 show an embodiment in which the vibrators 401 to 401 ″ are made of a piezoelectric material and the piezoelectric element portions 404 to 404 ″ are directly formed. As the piezoelectric material, a piezoelectric ceramic such as PZT (lead zircon titanate porcelain) or a composite piezoelectric material of piezoelectric ceramic and plastic is used.

In the example shown in FIG. 21, the vibrator 401 is composed of one U-shaped vibrator 402, and two adjacent sides 403 of opposite sides 403 having a rectangular cross section are arranged.
The piezoelectric element portion 404 utilizing the longitudinal effect of the primary mode is directly formed on the surface. In each piezoelectric element portion 404, a plurality of electrodes a ₁ and b ₁ perpendicular to the longitudinal direction of the opposite side 404 are arranged in the longitudinal direction, and every other electrode a ₁ and b ₁ is connected to the connecting portion a ₂ , b ₂ are connected to form two electrode sets a and b. That is, the electrodes a ₁ and b ₁ are provided in the crosswise direction in the lateral direction. A DC voltage is applied between the two electrode sets a and b to perform polarization treatment. + And-in the figure show the polarities of polarization. If the high-frequency voltage is applied by a power supply device similar to the power supply device 5 in FIG. 6 by performing the polarization process in this way, the opposite side 403 is expanded and contracted mainly by the piezoelectric vertical effect of the piezoelectric element portion 04, and bending vibration is performed. . Further, when a voltage having a phase difference is applied to the two adjacent piezoelectric element portions 404 of the facing side 403, the tip of the facing side 403 makes a circular or elliptical motion. Note that the electrodes a ₁ ,
Only two b _1's are needed.

In the example of FIG. 22, a piezoelectric element portion 404 'utilizing the piezoelectric lateral effect is formed on two adjacent surfaces of the opposing side 403'. In this example, the electrodes c and d are provided in a crosswise finger shape in the vertical direction. That is, each piezoelectric element portion 404 'forms an interdigital electrode composed of two or a plurality of parallel electrodes c and d along the longitudinal direction of the opposite side 403'. A DC voltage is applied between the electrodes c and d to perform polarization treatment. + And-in the figure show the polarities of polarization. When the high-frequency voltage is applied between the electrodes c and d by the polarization process as described above, the opposing side 403 'expands and contracts due to the piezoelectric lateral effect of the piezoelectric element portion 404' and causes bending vibration. The other constructional effects are similar to those of the embodiment shown in FIG.

In the example shown in FIG. 23, the vibrator 401 ″ has a single square-shaped vibrator 40.
In the embodiment using the 2 ″ secondary bending mode, each facing side 4
Two piezoelectric element parts 404 ″ utilizing the piezoelectric lateral effect are formed on each of two adjacent surfaces of 03 ″. That is,
Two electrodes e and f are provided in parallel on the opposite sides 403 ″ on both sides of the central portion in the longitudinal direction, and two electrodes e and f along the longitudinal direction are provided in parallel. Polarization is performed by applying a voltage.At this time, the first set of electrodes e and f and the second set of electrodes e and f are polarized with their polarities opposite to each other and a high frequency voltage of the same phase is applied or The same direction is applied, and a high frequency voltage of opposite polarity is applied.

By combining the vibrators 401 to 401 ″ of FIGS. 21 to 23 with the contact members 6, 36 and the like in the same manner as in the above embodiments, a reciprocating type or rotating type piezoelectric drive device is configured. To be done.

It should be noted that, similar to the example of FIGS. 21 to 23,
Even in the case where the vibrator is composed of a plurality of vibrators as in the examples of FIGS. 11, 11 and 16, the vibrator can be formed of a piezoelectric material to directly form the electrodes.

Further, similarly to the case of pasting, the piezoelectric element portions 404 to 404 ″ can be provided on the three or four surfaces of the opposite sides 403 to 403 ″, and the opposite sides 403 to 403 ″ can be vibrated in a higher order mode. It can also be configured to.

As described above, the piezoelectric elements such as piezoelectric ceramics are used for the vibrators 401 to 401 ″ and the piezoelectric elements 404 to 40 ″ are applied to the vibrators 401 to 401 ″.
By directly forming the 4 ″, the attachment of the piezoelectric element can be omitted, and the performance is stable because there is no adhesive layer. In addition, it is possible to make the shape complicated, and the cost and performance are improved. Thus, an advantageous piezoelectric drive device can be constructed.

〔The invention's effect〕

In the piezoelectric drive device of the present invention, since each vibrating body is U-shaped or R-shaped, both opposing sides thereof resonate with each other, and a large amplitude is obtained. Therefore, electrical energy can be efficiently converted into mechanical driving force. Further, since the resonance of the vibrating body is performed so that the base end where two opposite sides are continuous is in a non-vibrating state, by using the base end as a support portion, the support does not interfere with the vibration. From this, high efficiency can be obtained. Further, since there is a portion where the vibrating body does not vibrate as described above, either the vibrator or the contact member can be used as the fixed side or the movable side. Further, since the vibrating body has two opposing sides and contacts the contact member at this portion, the number of contact points is increased. Therefore, there is an effect that abrasion is reduced and stable driving is possible. When the piezoelectric element part is formed by directly forming electrodes on the piezoelectric material, unlike the case where the piezoelectric element is attached, there is no variation in characteristics due to attachment errors and the number of steps is reduced, improving productivity. To do.

[Brief description of drawings]

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 view of its vibration mode, and FIG. 4 (A) is a plan view of its vibrator. Fig. 4 (B)
Is also its front view, and FIG. 5 is also its operation explanatory diagram,
FIG. 6 is a block diagram of the power supply unit, FIGS. 7 (A) and 7 (B) are plan views and broken side views of another embodiment, and FIG. 8 (A) is a plan view of still another embodiment. ，
FIG. 8 (B) is a front view thereof, FIG. 9 is an operation explanatory view thereof, and FIG. 10 is a perspective view of a vibrator of still another embodiment.
FIG. 11 is a perspective view of a vibrator of still another embodiment, FIGS. 12 (A) and 12 (B) are respectively a plan view and a vertical sectional side view of the whole, and FIG. 13 is a perspective view of still another embodiment. , 14th
FIG. 16 is a cutaway side view thereof, FIG. 15 is an explanatory view of its vibration mode, FIG. 16 is a perspective view of a vibrator of still another embodiment,
FIG. 17 is a perspective view of the whole thereof, FIG. 18 is a principle explanatory view of still another embodiment, FIG. 19 is a principle explanatory view of yet another embodiment, and FIG. 20 is a principle explanation of yet another embodiment. FIGS. 21 and 23 are perspective views of vibrators according to further different embodiments. 1,1 ′, 1 ″, 101,401 to 401 ″ …… Resonator, 2,102,402,40
2 ′, 402 ″ …… Vibrator, 3,103,303,303 ′, 303 ″ …… Opposite side, 4,4 ₁ to 4 ₄ , 404,404 ′, 404 ″ …… Piezoelectric element part, 6,6 ′,
16,106,206,306 …… Contact member

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Takashi Takada, 1048 Kadoma, Kadoma City, Osaka Prefecture, Matsushita Electric Works, Ltd. (72) Seiki Ishibashi, 1048, Kadoma, Kadoma City, Osaka, Matsushita Electric Works, Ltd. (56) References JP-A-61-15572 (JP, A)

Claims (11)

[Claims] 1. A vibrating body, which is formed of an elastic material in a U-shape or a U-shape, and has a pair of opposing sides each having a substantially rectangular cross-section. A vibrator having a piezoelectric element section on at least two adjacent sides of each opposing side, wherein a predetermined high frequency voltage is applied to the piezoelectric element section, and the opposing side resonates by bending vibration; A power supply device that applies a high-frequency voltage with a phase difference between adjacent piezoelectric element parts, and a contact member that contacts each one of the facing sides of the vibrator, and the maximum amplitude of the facing side of the vibrator is provided. A piezoelectric drive device in which either the contact member or the vibrator is driven by the point making a circular or elliptical motion. 2. The piezoelectric drive device according to claim 1, wherein the piezoelectric element portion is formed by attaching a piezoelectric element to the vibrating body. 3. The vibrating body is made of piezoelectric ceramics,
The piezoelectric drive device according to claim 1, wherein the piezoelectric element portion is formed by directly forming a drive electrode on the piezoelectric ceramic. 4. The piezoelectric drive device according to claim 2 or 3, wherein the vibrator is composed of one vibrator. 5. The piezoelectric drive device according to claim 2, wherein the vibrator is composed of two vibrating bodies. 6. The two vibrating bodies are superposedly arranged with a predetermined space therebetween, and the contact member is a vibrating body.
The piezoelectric drive device according to claim 5, wherein the piezoelectric drive device is in contact with opposite sides of the pair. 7. The two vibrating bodies, wherein each vibrating body is U-shaped and arranged in an H shape, and the contact member is in contact with two pairs of opposing sides of the vibrating body. The piezoelectric drive device according to claim 5. 8. The piezoelectric driving device according to claim 2, wherein the contact member is formed in a flat plate shape, and either the contact member or the vibrator is linearly driven. 9. The piezoelectric drive device according to claim 2, wherein the contact member is formed in a disc shape, and either the contact member or the vibrator is rotationally driven. . 10. The contact member is formed in the shape of a round shaft extending between the pair of opposing sides in parallel with the opposing sides, and either the contact member or the vibrator is rotationally driven. The piezoelectric drive device according to claim 4. 11. The piezoelectric drive device according to claim 2, wherein the contact member is formed in a cylindrical shape, and either the contact member or the vibrator is rotationally driven.