JPH0470876B2 - - Google Patents

Description

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

[Background technology]

Conventionally, as an ultrasonic motor using piezoelectric elements,
There is one shown in Japanese Patent Publication No. 59-037672.
In this method, a piezoelectric element is attached to a vibrating body to generate longitudinal vibration, and a driving piece with an inclination is formed at the tip of the vibrating body. By contacting the disk, the disk 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 with longevity.

Further, as another conventional example, there is one shown 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 by vibrating one waveform with a 90° phase shift from the other waveform, a traveling wave is generated on the surface of the vibrating body, and a rotor is placed on top of the traveling wave. By making contact, the rotor is rotated by friction.

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

[Purpose of the invention]

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

[Disclosure of the invention]

The piezoelectric drive device of the present invention, to be described with reference to the reference numerals in the figures, is a piezoelectric drive device that includes a vibrator 1, a power supply device 5, and a contacted member 6, and the vibrator 1 has elasticity. It is formed into either a U-shape or a V-shape using a material, and the cross-sectional shape of the pair of opposing sides 3 is each approximately rectangular, and each has piezoelectric element portions 4 on at least two adjacent sides. The power supply device 5 applies a high frequency voltage to adjacent piezoelectric element portions 4 of each of the opposing sides 3 with a phase difference, thereby causing the maximum amplitude portion of each of the opposing sides 3 to move in a circular or elliptical manner. The contacted member 6 is in contact with the opposing side 3 of the vibrator 1, and the maximum vibration part of the opposing side 3 of the vibrator 1 is in contact with the opposing side 3 of the contacted member 6. At least a part of the contacting part is made of a permanent magnet 7, the other part is made of a magnetic material, and either the contacted member 6 or the vibrator 1 is made movable.

The piezoelectric element portion may be formed by adhering a piezoelectric element to the vibrator, or may be formed by forming the vibrator from a piezoelectric material and forming electrodes directly on this piezoelectric material. It's okay.

According to the configuration of the present invention, a high frequency voltage having a phase difference is applied to the piezoelectric element portions provided on two adjacent surfaces of each opposing side of the vibrator, so that the maximum amplitude point of each opposing side exhibits circular or elliptical motion. do. Since the contacted member comes into contact with one of the opposing sides, either the contacted member or the vibrator is driven by the frictional force, and a mechanical driving force is obtained.

In this case, since each vibrating body is U-shaped or square-shaped, both opposing sides resonate with each other and a large amplitude can be obtained. Therefore, electrical energy can be efficiently converted into mechanical driving force.

Further, since the vibrator and the contacted member are brought into contact with each other through a permanent magnet and a magnetic body, a stable contact force is obtained between the two due to magnetic force, and the drive by the frictional force is ensured. Moreover, along with the circular or elliptical motion of the vibrator, a moving force due to magnetic force is applied in the same direction as the traveling direction due to the frictional force. Therefore, a driving force that includes frictional force and magnetic force can be obtained, and efficient driving can be achieved. Furthermore, this efficiency can be improved with a simple structure that includes a permanent magnet.

Furthermore, since the resonance of the vibrator occurs in a non-vibrating state at the base end where two opposing sides are continuous, by using the base end as a support part, vibration can be prevented by the support. This also results in high efficiency. Further, since the vibrator has such a portion that does not vibrate, either the vibrator or the contacted member can be used as either a fixed side or a movable side. Furthermore, since the vibrator has two opposing sides and contacts the contacted member at these portions, the number of contact points is multiplied. Therefore, wear is reduced and stable driving is possible.

Embodiment A first embodiment of the present invention will be described based on FIGS. 1 to 6. This piezoelectric drive device is an example applied to a linear motor, and a vibrator 1 is formed by a vibrating member 2 made of a metal elastic material. That is, in this piezoelectric drive device, a piezoelectric element portion 4 is formed by pasting piezoelectric elements on two adjacent sides of a pair of opposing sides 3, each of which is formed in a U-shape and has a rectangular cross-section. When a predetermined high-frequency voltage is applied to the element section 4, the high-frequency voltage is applied to the vibrator 1 whose opposing sides 3 resonate by bending vibration, and to the adjacent piezoelectric element sections 4 on each opposing side 3 with a phase difference. Power supply device 5
, a permanent magnet 7 provided on each side of the opposite side 3 of the vibrator 1, and a contact member 6 made of a magnetic material that is brought into contact with the permanent magnet 7. Either the contacted member 6 or the vibrator 1 is driven by the circular or elliptical movement of the maximum amplitude point. In this case, the circular or elliptical motion of the permanent magnet 7 causes a change in magnetic flux between the permanent magnet 7 and the contacted member 6, and the permanent magnet 7 is driven by contact and magnetic force along with the circular or elliptical motion. Further, contact force is obtained between the vibrator 1 and the contacted member 6 by magnetic force.

The vibrating member 2 is made of a constant elastic material such as Erinba, but if accuracy and large amplitude are not required, general steel material, other metals, ceramics, etc. may also be used. If the vibrating member 2 is made of a magnetic material, the amount of change in magnetic flux is large and drive efficiency is improved. Although the cross-sectional shape of each opposing side 3 of the vibrator 1 is rectangular, each corner may be chamfered to have an octagonal cross-sectional shape, or the corners may be rounded instead of chamfered. In short, the opposing sides 3 only need to have a cross-sectional shape having four sides adjacent to each other at right angles. Vibrator 1
The base end portion 2a has a length that does not affect vibration even when fixed, and is fixed to a base 21 as shown in FIG. 2. The contact member 6 is supported by guide means (not shown) so as to be movable forward and backward relative to the base 21 in the direction of arrow P in FIG. Contacted member 6
are arranged so as to be in contact with point X and point Y (FIG. 4B), which are the tips of each side of the opposite side 3 to which the piezoelectric element portion 4 is not attached. Note that it does not necessarily have to be in contact with the tip. Further, the contacted member 6 may be brought into contact with a portion of the opposing side 3 on which the piezoelectric element portion 4 is not attached on one side thereof. Further, the vibrator 1 has three or four faces of a pair of opposing sides 3.
The piezoelectric element part 4 is pasted on the surface, and the piezoelectric element part 4 is pasted on one side on the opposite side 3 where the piezoelectric element part 4 is not pasted, or on the one side where the piezoelectric element part 4 is pasted. The to-be-contacted member 6 may be brought into contact with a portion that is not present. In these examples, the surface to which the piezoelectric element portion 4 of the opposing side 3 is attached may be brought into contact with the contacted member 6 via an insulating member.

The power supply device 5 has a high frequency power supply 8 and a 90° phase shifter 9 as shown in FIG _.
4 ₄ ) as shown in the same figure. The + and - signs in the figure indicate the polarization direction.

Operation Each piezoelectric element portion ₄ on the two opposing sides 3 of the vibrating body 2
4 ₄ , when a high frequency voltage is applied and excited by the power supply device 5 of FIG. 6, each opposing side 3 vibrates in the vertical and horizontal directions in accordance with the excitation of the respective piezoelectric element portions 4 ₁ to _{4 4} . At this time, when a voltage whose phase is delayed by 90° than that of the piezoelectric element parts 4 ₁ and 4 ₃ is applied to the piezoelectric element parts 4 ₂ and 4 ₄ , the X
The point, Y point, moves in a circular or elliptical orbit as shown in FIG. Therefore, when the contacted member 6 is arranged so as to be in contact with one surface of the opposing side 3, the contacted member 6 moves linearly in the direction of the arrow P. X
The flatness of the elliptical orbits of points and Y points is determined by the difference in bending rigidity depending on the bending direction of the opposing sides 3 and by the difference in bending rigidity of each piezoelectric element part 4 ₁
~4 It can be adjusted by adjusting the magnitude of the voltage applied to ₄ , the phase difference, etc.

If a voltage with a 90° advance phase is applied to the piezoelectric elements 4 ₂ and 4 ₄ , the contact member 6 will move in the opposite direction to the arrow P, drawing a trajectory opposite to that shown in FIG. 5 .

At this time, the permanent magnet 7 at the tip of the vibrator and the contacted member 6 made of a magnetic material attract each other and maintain a constant contact force, and furthermore, the permanent magnet 7 at the tip of the vibrator 1 The contacted member 6 moves due to the change in magnetic flux 7. That is, it is possible to obtain a driving force that is the sum of the frictional driving force due to the contact force and the driving force due to the magnetic force.

It operates in this way, but since each vibrator 1 is U-shaped, its opposite sides 3 resonate with each other,
Large amplitude can be obtained. Therefore, electrical energy can be efficiently converted into mechanical driving force. Also,
The resonance of the vibrator 1 is performed so that the base end 2a where the two opposing sides 3 are continuous is in a non-vibrating state as shown in FIG. 3A, so by using the base end 2a as a support part, , vibrations are not hindered by the support, which also provides high efficiency. Furthermore, since there are parts of the vibrator 1 that do not vibrate as described above, either the vibrator 1 or the contacted member 6 can be used as either a fixed side or a movable side. Furthermore, the vibrator 1 has two opposing sides 3,
Since this portion contacts the member to be contacted 6, the number of contact points is multiplied. Therefore, wear is reduced and stable driving is possible.

In this embodiment, the case where the opposing side 3 is vibrated in the first mode as shown in FIG. 3A has been explained.
As shown in FIGS. 3B and 3C, by vibrating in a higher-order mode such as a second-order mode or a third-order mode, the number of contact points of the opposite side 3 with the contacted member 6 can be further increased. This makes it possible to further reduce wear at the contact points and stabilize the operation.
The primary mode occurs when one piezoelectric element portion 4 is attached to the opposite side 3 in the longitudinal direction. 2
The next mode occurs when this single piezoelectric element section 4 is divided into two parts in the longitudinal direction and pasted together with the polarization directions reversed. In the tertiary mode, one piezoelectric element section 4
is divided into three parts in the longitudinal direction, and the piezoelectric elements in the center and the divided piezoelectric elements on both sides are pasted with opposite polarization directions, and when the same voltage is applied to each divided piezoelectric element using a common electrode on the same side, it emits. Indicates amplitude mode.

In the first embodiment shown in FIGS. 1 to 6, the permanent magnet 7 is provided on the side of the vibrator 1, and the contacted member 6 is made of a magnetic material.
may be a permanent magnet, and the vibrator 1 may be simply a magnetic material. The magnetic body includes a permanent magnet,
Both the contacted member 6 and the vibrator 1 may be permanent magnets.

In each of the embodiments described below in FIG. 7, either the contacted member or the vibrator may be a permanent magnet. In short, it is sufficient that one of the maximum amplitude portion of the opposite side of the vibrator and at least a part of the portion of the vibrator that contacts the opposite side is a permanent magnet, and the other is a magnetic material.

FIG. 7 shows an embodiment in which a vibrator 1 consisting of one U-shaped vibrating member 2 is used as a rotary motor. The contact member 16 made of a permanent magnet is formed into a disk shape, and its shaft 18 is rotatably supported on a base 17 by a bearing 19. Vibrator 1 made of magnetic material
is fixed to the vertical piece of the base 17 at the base end 2a. The two opposing sides 3 of the vibrator 1 are the contacted member 1
6, and its tip end is connected to the contacted member 16.
so that it is located on the outer periphery of the A friction piece 20 is attached to the tip of the opposing side 3, and the two vibrators 3 are vibrated so as to move circularly in the same direction, so that the contacted member 16 is rotated. The rest is the same as the first embodiment.

FIGS. 8 and 9 show two U-shaped vibrating members 2 made of magnetic materials arranged in a superimposed manner with an interval between them, and a contacted member 6 made of a permanent magnet between the upper and lower vibrating members 2. ′, the upper and lower vibrators 1 are connected to each other by a spacer (not shown) at the base end 2a.
They are superimposed via . Note that each vibrator 1 may be individually attached to a base (not shown) without using a spacer. Each point m, n, p, q on the opposite side 3 of the vibrator 101 is vibrated by the piezoelectric element 4 as shown in FIG. Drive straight ahead. In this case, since the two vibrators 1 are used for driving, an even larger output driving force can be obtained, and the operation can be stabilized. The rest is the same as the first embodiment. Both vibrating members 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 vibrating bodies 2 are oriented in opposite directions to form an integrated H-shaped vibrator 1''. use That is, a shaft 31 is fixed to the center of a vibrator 1' made of a magnetic material, the shaft 31 is fixed to a base 37, and a contact member 36 made of a disc-shaped permanent magnet on which a bearing 38 is attached is attached to the shaft 31. The tip of the four opposing sides 3 is placed on the outer periphery of the contacted member 36. Then, by bending the ends of the four opposing sides 3 so as to make a circular motion in the same direction by each piezoelectric element portion 4, the contacted member 36 rotates, thereby forming a rotary motor. The rest is the same as the first embodiment.

FIGS. 13 to 15 show an embodiment using a vibrator 101 consisting of one square-shaped vibrating member 102. FIG. In this example, when the vibration is in the first mode, the point at the center of the opposing side 103 moves in a circle or an ellipse, and when the contacted member 106 is brought into contact with the plane part, the circular or ellipse movement at the center causes The contacted member 106 will move. The contacted member 106 can be directly supported so as to move forward and backward in the direction of the arrow Q to form a linear motor, or the contacted member 106 can be supported rotatably to form a rotary motor. In this example, the vibrations are as shown in FIG. 15A in the primary mode, and the vibrations as shown in FIGS. 15B and C in the secondary and tertiary modes, respectively. 121 is a base. The method of polarizing the piezoelectric element portion 4 is the same as described above. Other structural effects are the same as in the first embodiment.

16 and 17, two rectangular-shaped vibrators 101 made of magnetic material are arranged in a superposed manner with a spacer 105 in between, and a contacted member 106 made of a permanent magnet is placed between both vibrators 101. are arranged so that they can move forward and backward in a straight line in the direction of arrow Q. The piezoelectric element portion 4 is attached to the four opposing sides 103 so as to move as shown in FIG. The rest is the same as the first embodiment.

In each of the above embodiments, the piezoelectric element part 4 was attached only to two adjacent sides of the opposing sides 3, 103, but even if the piezoelectric element part 4 was attached to three sides,
You can also paste it on the surface. When pasting on three surfaces, it is desirable that the contacted members 6, 6', and 106 be brought into contact with the remaining one surface. In the case of pasting on four sides, it is desirable that the opposing sides 3 and the contacted members 6, 6', 106 are brought into contact with each other via an insulating member.
The insulating member may be provided on the 6, 6', and 106 sides, or may be provided on the opposing side 3 side.

18 to 20 each show a vibrator 401
401'' is formed of a piezoelectric material, and an embodiment in which piezoelectric element portions 404 to 404'' are directly formed is shown. As the piezoelectric material, a piezoelectric ceramic such as PZT (lead zirconium titanate porcelain) or a composite piezoelectric material of piezoelectric ceramic and plastic is used. Although these piezoelectric materials do not have magnetism,
The vibrators 401-
401'' may have the characteristics of a magnetic material.Also, instead of mixing magnetic materials, each electrode provided on the vibrators 401 to 401'' as described later may be formed of a magnetic material, and the vibrator 401~401″
may have the effect of a magnetic substance.

In the example shown in FIG. 18, the vibrator 401 is made up of one U-shaped vibrating member 402, and piezoelectric elements using the longitudinal effect of the first mode are provided on two adjacent sides of the opposing sides 403 of a rectangular cross-sectional shape. 404 is directly formed. Each piezoelectric element section 404 has a plurality of electrodes a ₁ and b ₁ arranged perpendicularly to the longitudinal direction of the opposing side 404, and every other electrode
Two electrode sets a _and b are formed by connecting _{a 1 and} b ₁ to each other at connecting portions a 2 and b 2 . That is, the electrodes a ₁ and b ₁ are provided in an interdigital pattern in the lateral direction. A DC voltage is applied between these two electrode sets a and b to perform a polarization process. + and - in the figure indicate the polarity of polarization. If polarization is performed in this way and a high frequency voltage is applied by a power supply device similar to the power supply device 5 in FIG.
3, the piezoelectric element portion 404 expands and contracts mainly due to the piezoelectric longitudinal effect, thereby causing bending vibration. Also, the opposite side 4
When voltages having a phase difference are applied to the piezoelectric element portions 404 on two adjacent sides of 03, the tips of the opposing sides 403 perform circular or elliptical motion. Note that each piezoelectric element section 40
Only two electrodes a ₁ and b ₁ may be provided in No. 4.

In the example of FIG. 19, two adjacent sides of the opposite side 403'
A piezoelectric element portion 404' is formed on the surface by utilizing a piezoelectric transverse effect. In this example, the electrodes c and d are arranged in a vertically interdigitated manner. That is, each piezoelectric element portion 404' forms an interdigital electrode consisting of two or many parallel electrodes c and d along the longitudinal direction of the opposing side 403'. A DC voltage is applied between the electrodes c and d to perform polarization treatment. + and - in the figure indicate the polarity of polarization. If a high frequency voltage is applied between electrodes c and d after polarization treatment in this way, the opposite side 40
3' causes the piezoelectric element portion 404' to expand and contract due to the piezoelectric transverse effect, thereby performing bending vibration. Other structural functions are similar to the embodiment shown in FIG. 18.

The example shown in FIG. 20 is an embodiment in which the vibrator 401'' utilizes the second-order bending mode of one square-shaped vibrating member 402'', and the piezoelectric Piezoelectric element section 404″ using transverse effect
Two pieces each were formed. That is, located on both sides of the central part in the longitudinal direction on the opposing sides 403'',
Four electrodes e and f along the longitudinal direction are provided in parallel, two each, and a set of two parallel electrodes is formed, and a DC voltage is applied between these two electrodes to perform polarization.
The electrodes e, f of the first set and the electrodes e, f of the second set 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. .

The vibrator 401 in FIGS. 18 to 20
401'' and in combination with the contact members 6, 36, etc. in the same manner as in the above embodiments, a reciprocating type or rotary type piezoelectric drive device is constructed.

Similarly to the examples shown in FIGS. 18 to 20, even in cases where the vibrator is composed of a plurality of vibrating members as in the examples shown in FIGS. 10, 11, and 16, the vibrator is piezoelectric. It is also possible to form the electrode directly by forming the material.

Also, as in the case of pasting, the opposite sides 403 to
Piezoelectric element parts 404~ on 3 or 4 sides of 403''
404'' may also be provided, and it may also be configured to vibrate the opposing sides 403 to 403'' in a higher order mode.

In this way, the vibrators 401 to 401'' are made of piezoelectric material such as piezoelectric ceramic.
By forming the piezoelectric elements 404 to 404'' directly on the piezoelectric elements 404 to 404'', it is possible to omit pasting the piezoelectric elements, and since there is no adhesive layer, the performance can be stabilized. Also,
Unlike those in which piezoelectric elements are pasted, there is no variation in characteristics due to pasting errors, and the number of man-hours is reduced, improving productivity. Furthermore, it is possible to create a piezoelectric drive device that is complex in shape, and is advantageous in terms of cost and performance.

〔Effect of the invention〕

In the piezoelectric drive device of the present invention, since the vibrator is U-shaped or square-shaped, both opposing sides resonate with each other and a large amplitude can be obtained. Moreover, since a permanent magnet and a magnetic body are provided between the vibrator and the contacted member, a constant contact force can be obtained extremely easily, and the driving force is increased by the magnetic force, which reduces electrical energy. It can be efficiently converted into mechanical driving force.

In addition, since the resonance of the vibrator occurs in a non-vibrating state at the base end where two opposing sides are continuous, by using the base end as a support part, vibration can be prevented by the support. This also results in high efficiency. Furthermore, since the vibrator has a portion that does not vibrate, either the vibrator or the contacted member can be used as either a fixed side or a movable side. Furthermore, since the vibrator has two opposing sides and contacts the contacted member at these portions, the number of contact points is multiplied. This has the effect of reducing wear and enabling stable driving.

[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, FIG. Figure B is a front view of the same, Figure 5 is an explanatory diagram of its operation, Figure 6 is a block diagram of the power supply device, Figures 7A and B are a plan view and a cutaway side view of other embodiments, respectively. FIG. 8A is a plan view of yet another embodiment, FIG. 8B is a front view thereof, FIG. 9 is an explanatory diagram of its operation, and FIG. 11 is a perspective view of a vibrator according to another embodiment, FIGS. 12A and 12B are a cutaway plan view and a longitudinal side view of the entire vibrator, respectively, and FIG. 13 is a perspective view of still another embodiment.
FIG. 4 is a cutaway side view of the same, FIG. 15 is an explanatory diagram of its vibration mode, FIG. 16 is a perspective view of a vibrator of another embodiment, FIG. 17 is a perspective view of the entire vibrator, and FIGS. FIG. 20 is a perspective view of a vibrator in still another embodiment different from each other. 1,1',1'',101,401~401''...
Vibrator, 2, 102, 402, 402', 40
2″……Vibration member, 3,103,303,30
3', 303''...opposite side, 4, _{4 1} to 4 _4, 40
4,404',404''...Piezoelectric element section, 5...Power supply unit, 6,6',16,106,206,3
06... Contacted member, 7... Permanent magnet.

Claims (1)

[Scope of Claims] 1. A piezoelectric drive device including a vibrator 1, a power supply device 5, and a contacted member 6, wherein the vibrator 1 is made of an elastic material and has a U-shape and an open-shape shape. The power supply device 5 is formed in any shape, and each of the pair of opposing sides 3 has a substantially rectangular cross-sectional shape, and each has a piezoelectric element portion 4 on at least two adjacent sides, and the power supply device 5 By applying a high frequency voltage to adjacent piezoelectric element portions 4 of sides 3 with a phase difference, the maximum amplitude portion of each of the opposing sides 3 is caused to move in a circular or elliptical manner, and the contacted member 6 is caused to move in a circular or elliptical manner. one of the maximum amplitude part of the opposing side 3 of the vibrator 1 and at least a part of the part of the connected member 6 that comes into contact with the opposing side 3; A piezoelectric drive device in which a permanent magnet 7 is used, a magnetic material is used, and either the contacted member 6 or the vibrator 1 is movable. 2. The piezoelectric drive device according to claim 1, wherein the piezoelectric element portion is formed by adhering a piezoelectric element to the vibrator. 3. The piezoelectric drive device according to claim 1, wherein the vibrator is made of piezoelectric ceramic, and the piezoelectric element portion has drive electrodes formed directly on the piezoelectric ceramic. 4. The piezoelectric drive device according to claim 2 or 3, wherein the vibrator includes one vibrating member. 5. The piezoelectric drive device according to claim 2 or 3, wherein the vibrator includes two vibrating members. 6. The method according to claim 5, wherein the two vibrators are arranged in a superimposed manner with a predetermined interval therebetween, and the contacted member is contacted with two pairs of opposing sides of the vibrator. Piezoelectric drive device. 7. The two vibrator members each have a U-shape and are arranged in an H shape, and the contacted member is in contact with two pairs of opposing sides of the vibrator. A piezoelectric drive device according to claim 5. 8. The piezoelectric drive device according to claim 2 or 3, wherein the contacted member is formed into a flat plate shape, and either the contacted member or the vibrator is linearly driven. 9. The piezoelectric drive device according to claim 2 or 3, wherein the contacted member is formed in a disk shape, and either the contacted member or the vibrator is rotationally driven. 10. The piezoelectric drive device according to any one of claims 1 to 9, wherein the vibrator is made of a magnetic material. 11. The piezoelectric drive device according to any one of claims 1 to 9, wherein the vibrator is made of a magnetic material that is not a permanent magnet, and the portion that contacts the opposing side of the contacted member is made of a permanent magnet. .