JP2001286167A - Adjustment method of piezoelectric actuator and piezoelectric actuator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate adjustment of the drive characteristics of a piezoelectric actuator. SOLUTION: Weight balance on an oscillating plate 10 is changed by changing the shape of an adjustment part 18 on the vibration plate 10. An angle ψ between a line R passing the center of a rotor 30 parallel to the longitudinal direction of the oscillating plate 10 and the long axis directional line T of an elliptical orbit moved by a projection part 17 is changed by changing the weight balance, and the drive characteristics of the piezoelectric actuator is adjusted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for adjusting a piezoelectric actuator and a piezoelectric actuator.
The present invention relates to a technique that facilitates adjustment of drive characteristics of a piezoelectric actuator.

[0002]

2. Description of the Related Art Various types of piezoelectric actuators utilizing the piezoelectric effect of piezoelectric elements have been developed recently because piezoelectric elements have excellent conversion efficiency from electric energy to mechanical energy and excellent responsiveness. This piezoelectric actuator includes a piezoelectric buzzer, a printer inkjet head,
Alternatively, it is applied to fields such as ultrasonic motors.

[0003]

By the way, the driving characteristics of the piezoelectric actuator are designed at the design stage according to the characteristics of the product to which the piezoelectric actuator is attached. However, since the actually manufactured parts have individual differences such as dimensional variations, the driving characteristics of the assembled piezoelectric actuator may change for each piezoelectric actuator, and the designed driving characteristics may not be obtained. was there. As described above, no method has been proposed for easily adjusting the fluctuation of the driving characteristics due to the dimensional variation or the like individually after the products are mounted.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and a piezoelectric actuator adjustment method and a drive characteristic capable of easily adjusting drive characteristics even after the piezoelectric actuator has been assembled. It is an object of the present invention to provide a piezoelectric actuator that can easily adjust the pressure.

[0005]

According to a first aspect of the present invention, there is provided a diaphragm including a support, a plate-shaped piezoelectric element having a longitudinal direction, and a reinforcing portion laminated on each other. A vibration plate supported so as to be able to vibrate with respect to the support, and adjusting a driving characteristic of a piezoelectric actuator that drives a driving target that is in contact with an end portion at one end side in the longitudinal direction of the vibration plate. In the adjusting method, the driving characteristic of the piezoelectric actuator is adjusted by changing the shape of the diaphragm after attaching the diaphragm to a predetermined position.

According to a second aspect of the present invention, in the method for adjusting a piezoelectric actuator according to the first aspect, the piezoelectric actuator moves the end along an elliptical orbit by vibrating the diaphragm. Driving the driven object in contact with the end portion in a predetermined driving direction, and changing the shape of the diaphragm so that the major axis direction of the elliptical orbit substantially matches the predetermined driving direction. It is characterized by being adjusted to.

According to a third aspect of the present invention, in the method for adjusting a piezoelectric actuator according to any one of the first and second aspects, the shape of the diaphragm is changed by deleting a part of the diaphragm. It is characterized by.

According to a fourth aspect of the present invention, in the method for adjusting a piezoelectric actuator according to the first aspect, the diaphragm has a projection projecting from the end, and the shape of the projection is changed. The driving characteristic of the piezoelectric actuator is adjusted.

According to a fifth aspect of the present invention, there is provided a diaphragm in which a support, a plate-shaped piezoelectric element having a longitudinal direction, and a reinforcing portion are laminated, and is supported so as to be able to vibrate on the support. And a driving unit provided on one end side of the vibration plate in the longitudinal direction and brought into contact with an object to be driven, and vibrating the vibration plate to move the driving unit along an elliptical orbit. Thus, a piezoelectric actuator that drives the drive target in contact with the drive unit in a predetermined drive direction,
The vibration plate includes an adjusting portion having a higher density than the reinforcing portion.

According to a sixth aspect of the present invention, there is provided a diaphragm in which a support, a plate-shaped piezoelectric element having a longitudinal direction, and a reinforcing portion are laminated, and is supported so as to be able to vibrate on the support. And a driving unit provided on one end side of the vibration plate in the longitudinal direction and brought into contact with an object to be driven, and vibrating the vibration plate to move the driving unit along an elliptical orbit. Thus, a piezoelectric actuator that drives the drive target in contact with the drive unit in a predetermined drive direction,
The vibration plate includes an adjusting portion having a lower yield stress than the reinforcing portion.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [1] Embodiment [1.1] Overall Configuration The present invention allows the weight balance of a diaphragm, which will be described later, provided in a piezoelectric actuator, even after the piezoelectric actuator has been assembled. The present invention relates to an adjustment method capable of easily adjusting the drive characteristics of a piezoelectric actuator by changing the adjustment method. Hereinafter, a piezoelectric actuator to which an adjustment method according to an embodiment of the present invention is applied will be described with reference to the drawings.

FIG. 1 is a plan view showing a main structure of a calendar display mechanism incorporating a piezoelectric actuator in a wristwatch according to the present embodiment. The piezoelectric actuator A1 is substantially constituted by a diaphragm 10 and a rotor 30 which expand and contract in an in-plane direction (a direction parallel to the plane of the drawing). The rotor 30 is rotatably supported by a base plate (support) 70 and is arranged at a position where the rotor 30 comes into contact with the projection 17 of the diaphragm 10. As a result, the protrusions 17 move along an elliptical orbit as described later due to the vibration generated in the diaphragm 10, and the protrusions 17 come into contact with the outer peripheral surface of the rotor 30. In the direction of rotation.

The calendar display mechanism is connected to the piezoelectric actuator A1, and is driven by the driving force of the piezoelectric actuator A1. The main part of the calendar display mechanism is roughly composed of a reduction wheel train including a date dial intermediate wheel 40 and a date wheel 60 for reducing the rotation of the rotor 30, and a ring-shaped date wheel 50.

[1.2] Piezoelectric Actuator Next, a piezoelectric actuator A1 according to this embodiment will be described with reference to FIG. As shown in FIG. 2, the piezoelectric actuator A1 has a long plate-shaped vibration plate 10 formed to be long in the vertical direction in the figure, and a ground plate 70 (see FIG. 1).
).

At one end 15 in the longitudinal direction of the vibration plate 10, a projection (drive unit) 17 is provided so as to project toward the rotor 30, and the projection 17 is formed on the outer periphery of the rotor 30. Is in contact with the surface. As the projection 17, a conductor or a non-conductor can be used, but if it is formed of a non-conductor, the rotor 3 generally formed of a metal can be used.
It is possible to prevent a piezoelectric element to be described later from being short-circuited even when it comes into contact with zero. The projection 17 has a curved shape protruding toward the rotor 30 in plan view. By forming the protrusion 17 in contact with the rotor 30 into a curved surface in this manner, even when the positional relationship between the rotor 30 and the diaphragm 10 varies due to dimensional variations or the like, the curved outer peripheral surface of the rotor 30 and the curved surface shape may be used. The contact state with the projection 17 does not change so much. Therefore, a stable contact state between the rotor 30 and the projection 17 can be maintained.

An adjusting portion 18 for adjusting the weight balance of the diaphragm 10 is provided at the other end 16 in the longitudinal direction of the diaphragm 10. The adjusting section 18 is provided for adjusting the vibration characteristics by a method for adjusting the vibration characteristics of the diaphragm 10 described later. Further, one end 21 of the support member 20 is attached to the rotor a little from the center in the longitudinal direction of the diaphragm 10. The other end 2 of the support member 20
2 is supported on the main plate 70 (see FIG. 1) by the pins 23. Under this configuration, the support member 20 supports the diaphragm 10 in a state where the diaphragm 10 is urged toward the rotor 30 by its elastic force, so that the projection 17 of the diaphragm 10 abuts on the outer peripheral surface of the rotor 30. Have been allowed.

Next, the configuration of the diaphragm 10 will be described with reference to FIG. As shown in FIG.
Between the two rectangular piezoelectric elements 11 and 12, the piezoelectric elements 1 and 12 have substantially the same shape and
It has a laminated structure in which a reinforcing plate (reinforcing portion) 13 of stainless steel or the like thinner than 1 and 12 is arranged. By arranging the reinforcing plate 13 between the piezoelectric elements 11 and 12 in this manner, it is possible to reduce damage to the diaphragm 10 due to excessive amplitude of the diaphragm 10 or external force. Reinforcement plate 1
As 3, the vibration of the piezoelectric elements 11 and 12 is prevented as much as possible by using a thinner element than the piezoelectric elements 11 and 12. Further, electrodes 14 are arranged on the surfaces of the piezoelectric elements 11 and 12 arranged vertically. Then, the piezoelectric element 1 is
A voltage is supplied to the terminals 1 and 12. The diaphragm 10 having such a configuration supplies power to the diaphragm 10
When an AC voltage is applied to the piezoelectric elements 11 and 12 via the electrode 14 from a drive circuit (not shown) that vibrates the piezoelectric elements 11 and 12, the piezoelectric elements 11 and 12 expand and contract.
As shown in FIG. 4, longitudinal vibration occurs.

Here, when the diaphragm 10 undergoes longitudinal vibration that expands and contracts in the longitudinal direction of the diaphragm 10 as shown in FIG.
A rotational moment about the center of gravity of the diaphragm 10 is generated by the protrusion 17 and the adjustment unit 18. Then, a bending vibration that oscillates in the width direction orthogonal to the longitudinal direction of the diaphragm 10 as shown in FIG. 5 is excited on the diaphragm 10 by the rotational moment, and as a result, the protrusion 17
As shown in (2), it moves along an elliptical orbit. The magnitude of the rotational moment differs depending on the degree of imbalance of the weight balance of the diaphragm 10. And
If the magnitude of the rotational moment is different, the excited bending vibration is also different. Therefore, if the weight balance of the diaphragm 10 is changed, the vibration characteristics also fluctuate, and the method of adjusting the vibration characteristics of the diaphragm 10 described later adjusts the vibration characteristics using such a principle. .

The piezoelectric elements 11 and 12 are made of lead zirconate titanate (PZT (trademark)), quartz, lithium niobate, barium titanate, lead titanate, lead metaniobate, polyvinylidene fluoride, zinc niobium zinc Lead oxide ((Pb (Zn1 / 3-Nb2 / 3) 031-x-PbTi03x) x varies depending on the composition. X = 0.09), lead scandium niobate ((Pb ((Sc1 / 2-Nb1 / 2) 1-x Tix) 03) x varies depending on the composition. X = 0.09).

From the above, the piezoelectric actuator A1
When a voltage is applied to the diaphragm 10 from a drive circuit (not shown), the piezoelectric elements 11 and 12 expand and contract to vibrate longitudinally and flexibly. As shown in FIG.
The projection 17 moves along the elliptical trajectory in a state of contact with 0, and the rotor 30 is rotated in the direction of the arrow in FIG. In this way, by rotating the rotor 30, the date driving wheel 60 is rotated via the date driving intermediate wheel 40 (see FIG. 1), and the displayed day or day is switched.

[1.3] Configuration for Obtaining High Driving Efficiency The piezoelectric actuator A1 used in the method of adjusting the vibration characteristics of the diaphragm 10 moves the protrusion 17 along an elliptical orbit as described above. Accordingly, it is possible to drive the rotor 30 with high efficiency. The inventor of the present application analyzed the relationship between the direction of the ellipse and the driving efficiency in order to further improve the driving efficiency, and obtained the results shown in FIG. Here, the angle φ in FIG. 9 will be described with reference to FIG. As shown in FIG. 8, the angle φ is such that the tangent S on the outer peripheral surface of the rotor 30 at the contact point P where the projection 17 of the diaphragm 10 contacts the outer peripheral surface of the rotor 30 and the projection 17 of the diaphragm 10 This is the angle formed by the long axis direction T of the moving elliptical orbit. As shown in FIG. 9, when the tangent line S on the outer peripheral surface of the rotor 30 and the major axis direction line T of the elliptical orbit on which the projection 17 moves are at an angle φ of 0, that is, when the two coincide, High driving efficiency can be obtained. Therefore, the piezoelectric actuator A1 and the rotor 30 are set so that the angle φ formed by the tangent S on the outer peripheral surface of the rotor 30 and the major axis direction T of the elliptical orbit on which the protrusion 17 moves is 0 degree. Is most preferred. However, the angle φ described above is ±
In the case where the angle falls within the range of about 5 degrees, almost the same effect as the effect obtained at the time of the maximum driving efficiency is obtained. If the angle φ falls within this range, sufficient driving efficiency is obtained. It is thought that can be obtained.

Taking into account the relationship between the direction of the ellipse and the driving efficiency, the piezoelectric element is so arranged that the tangent S on the outer peripheral surface of the rotor 30 and the major axis T of the elliptical orbit on which the projection 17 moves substantially coincide with each other. It is preferable to configure the actuator A1 in order to improve the driving efficiency. Therefore, in the present embodiment, the components constituting the piezoelectric actuator A1 are designed so that the tangent line S and the long axis direction line T substantially coincide with each other. However, at the design stage, the rotor 30
Even if each component is designed such that the tangent S on the outer peripheral surface thereof coincides with the long-axis direction T of the elliptical trajectory on which the protrusion 17 moves, the rotor 30 may not move due to the dimensional variation of each component. A desired driving efficiency may not be obtained because the tangent line S on the outer peripheral surface does not coincide with the major axis direction line T of the elliptical orbit on which the protrusion 17 moves. The present invention adjusts the vibration characteristics of the diaphragm 10 in such a case, and a method of adjusting the vibration characteristics of the diaphragm 10 will be described in detail below.

[1.4] Method of Adjusting Vibration Characteristics First, FIG. 7 is a graph showing the relationship between the angle ψ and the mass of the adjusting section 18 shown in FIG. As shown in FIG. 7, as the mass of the adjusting unit 18 increases, the angle ψ also increases by 90 degrees.
The degree line increases as asymptote. This means that the adjustment unit 1
This shows that the angle ψ can be reduced by reducing the mass of the weight 8 and reducing the unbalance of the weight balance.

Here, the adjusting portion 18 includes the reinforcing plate 13.
It is preferable to use gold, tungsten, lead, or the like having a higher density. As described above, in the method of adjusting the vibration characteristics of the diaphragm 10, a member having a higher density than stainless steel, iron, or the like, which is mainly used as the reinforcing plate 13, is used as the member of the adjustment unit 18, so that the weight balance can be reduced. It is possible to reduce the processing amount of the member for adjustment, and it is possible to more easily adjust the weight balance.

Further, the adjusting portion 18 includes the reinforcing plate 13.
It is preferable to use a copper-based member such as copper, brass, and bronze having a lower yield stress. As described above, in the method of adjusting the vibration characteristics of the diaphragm 10, by using a member having a lower yield stress than stainless steel, iron, or the like mainly used as the reinforcing plate 13 as a member of the adjusting unit 18, weight balance is achieved. It is possible to easily process a member for adjusting the weight, and thus, it is possible to more easily adjust the weight balance.

Next, a method of adjusting the vibration characteristics of the diaphragm 10 by shaving the adjusting section 18 using the above-described members will be described. First, the diaphragm 10 and the rotor 30
If it is necessary to adjust the vibration characteristics of the diaphragm 10 without obtaining the desired driving efficiency after the is attached to the base plate 70, the members of the adjustment unit 18 are cut off and the shape of the adjustment unit 18 is changed. Thus, the angle φ (see FIG. 8) formed by the tangent line S and the long-axis direction line T is adjusted to be 0 degrees.

With reference to FIG. 10, a specific adjustment method will be described. For example, when the contact angle θ of the protrusion 17 to the rotor 30 shown in FIG. 10 is 30 degrees,
A line R passing through the center of the rotor 30 parallel to the longitudinal direction of the diaphragm 10 and a longitudinal axis line T of an elliptical orbit on which the protrusion 17 moves.
Is adjusted to 60 degrees, that is, equal to the angle ω shown in FIG. 10, the long axis direction line T of the elliptical orbit substantially coincides with the tangent line S on the outer peripheral surface of the rotor 30. Become like Here, since the relationship between the mass of the adjustment unit 18 and the angle ψ is the relationship shown in the graph shown in FIG. 7, the angle ψ is reduced by cutting the adjustment unit 18 to reduce the mass of the adjustment unit 18. Adjust to 60 degrees.

[1.5] Effects of the Embodiment As described above, according to the embodiment, after the piezoelectric actuator is assembled, the members of the adjusting portion 18 having a higher density and a lower yield stress than the reinforcing plate 13 are used. By shaving, it becomes possible to obtain desired vibration characteristics of diaphragm 10. Therefore, even after assembling the piezoelectric actuator A1, the vibration characteristics of the vibration plate 10 can be adjusted, and the same adjustment can be performed with a smaller processing amount than processing the same member as the reinforcing plate 13. And also
Since the processing is easier than processing the same member as the reinforcing plate 13, the vibration characteristics of the diaphragm 10 can be adjusted more easily. As described above, according to the method for adjusting the vibration characteristics of the diaphragm 10 according to the present embodiment, the drive characteristics can be adjusted only by shaving the adjustment unit 18, so that a method for easily adjusting the drive characteristics is provided. It becomes possible.

[2] Modifications [2.1] First Modification In the above-described embodiment, the vibration characteristics of the diaphragm 10 are adjusted by cutting the adjusting portion 18 provided on the diaphragm 10. Although the rotor 30 was driven, FIG.
As shown in FIG. 7, a notch 19 that cuts in the plane direction may be provided in the protrusion 17, and the vibration characteristic of the protrusion 17 may be adjusted by cutting the cut 19 to drive the rotor 30. In the present modified example, the notch 19 is provided in the projection 17, so that the projection 17 locally bends and vibrates due to the reaction force from the rotor 30 against the longitudinal vibration generated in the diaphragm 10. Therefore, by adjusting the bending vibration, the driving characteristics of the piezoelectric actuator A1 are adjusted.

Referring to FIGS. 12 and 13, FIG.
As one method for adjusting the drive characteristics of the piezoelectric actuator A1 shown in FIG. 1, an adjustment method in the case where the tangent S on the outer peripheral surface of the rotor 30 and the major axis direction T of the elliptical orbit on which the protrusion 17 moves is made to coincide. Will be described. As shown in FIG. 12, the size of the cut portion 19 is determined by the depth h of the cut in the planar direction of the projection 17 and the width t of the cut. Then, the magnitude of the bending vibration excited in the cut portion 19 by the reaction force from the rotor 30 is determined by the cut depth h and the cut width t.

The angle ψ shown in FIG. 11 is a line R passing through the center of the rotor 30 parallel to the longitudinal direction of the diaphragm 10.
And the major axis line T of the elliptical orbit on which the projection 17 moves. Here, FIG. 13 is a graph showing the relationship between the angle ψ and the depth h of the cut when the width t of the cut is constant. As shown in FIG.
As the angle increases, the angle ψ also increases. Therefore, by adjusting the depth h of the cut and the width t of the cut, it is possible to change the inclination of the major axis direction line T of the elliptical orbit on which the projection 17 moves.

As described above, by changing the cut depth h and the cut width t of the cut portion 19, the size of the elliptical orbit along which the projection 17 moves and the longitudinal axis T of the elliptical orbit are changed. Direction can be changed. Therefore,
By changing the notch depth h and the notch width t, the difference between the tangent S on the outer peripheral surface of the rotor 30 shown in FIG. It is possible to set the indicated angle φ to be 0 degrees.

As described above, in the present modification, the frequency of the bending vibration generated in the notch 19 is changed only by shaving the notch 19 in order to adjust the notch depth h and the notch width t. Therefore, it is possible to provide the piezoelectric actuator A1 that can easily adjust the drive efficiency even when the adjustment of the drive efficiency is difficult due to design reasons.

[2.2] Second Modification In each of the above-described embodiments, the rotor 30 is described as an example of a drive target of the piezoelectric actuator A1, but the drive target is a disk-like rotor or the like. There is no need to be limited to this, and a driving target such as a plate-like body or a rod-like body may be used. In this case, the piezoelectric actuator A1 is
Is vibrated to move the projection 17 as a driving unit along an elliptical trajectory, so that a driving target such as a plate-like body or a rod-like body which comes into contact with the projection 17 is moved in a predetermined driving direction, for example, a plate-like body or a rod-like body. It is driven in the longitudinal direction of the body or the like.

[2.3] Third Modification In each of the above-described embodiments, the member of the adjustment unit 18 is deleted as a processing method of the adjustment unit 18. However, the method is not limited to the deletion. Any processing method such as adding, detaching, or fitting 18 members may be used. In short, it suffices if the weight balance can be changed by deforming the shape of the member of the adjustment unit 18.

[2.4] Fourth Modification In each of the above-described embodiments, as a method of adjusting the vibration characteristics of the diaphragm 10, the protrusion 17 of the diaphragm 10 is in contact with the outer circumferential circle of the rotor 30. An adjustment method is described in the case where the tangent line S on the outer circumferential circle of the rotor 30 at the contact point P to be made coincides with the major axis direction line T of the elliptical orbit on which the projection 17 of the diaphragm 10 moves. The present invention is not limited to this, and any method may be used as long as it is adjusted so as to obtain desired vibration characteristics at the design stage.

[2.5] Fifth Modification The setting position of the adjusting section 18 does not need to be the position shown in FIG. 2, and the rotational moment is applied when the diaphragm 10 generates longitudinal vibration. Vibration plate 10 at the position where it is generated
It may be set in any of the above parts. However, by setting the adjustment unit 18 at the position shown in FIG. 2, that is, at a position diagonally across the projection 17 and the diaphragm 10, the adjustment unit 18 is set at a position different from that at other positions. Can be easily cut without interfering with the support member 20, the rotor 30, and the like, and the weight balance can be easily reflected.

[2.6] Sixth Modification In the above-described embodiment, the piezoelectric actuator is mounted not only on the calendar display mechanism of the timepiece described above but also on portable equipment other than the timepiece. It is also possible to use.

[0039]

As described above, according to the present invention, the drive characteristics of the piezoelectric actuator can be easily adjusted even after the piezoelectric actuator has been assembled.

[Brief description of the drawings]

FIG. 1 is a plan view showing a main configuration of a calendar display mechanism incorporating a piezoelectric actuator in a timepiece according to each embodiment of the present invention.

FIG. 2 is a plan view showing the overall configuration of a piezoelectric actuator.

FIG. 3 is a side sectional view showing a diaphragm which is a component of the piezoelectric actuator.

FIG. 4 is a diagram showing a state where a diaphragm vibrates longitudinally.

FIG. 5 is a diagram illustrating a state in which a diaphragm vibrates flexibly when vibrated.

FIG. 6 is a diagram for explaining the behavior of a protrusion during bending vibration.

FIG. 7 is a graph showing a relationship between an angle ψ and a mass of an adjustment unit.

FIG. 8 is a diagram showing a positional relationship between a piezoelectric actuator and a rotor.

FIG. 9 is a graph showing the relationship between the angle φ and the driving efficiency of the piezoelectric actuator.

FIG. 10 is a plan view illustrating a method for adjusting vibration characteristics.

FIG. 11 is a plan view showing the overall configuration of a piezoelectric actuator according to a first modification.

FIG. 12 is a plan view showing a configuration of a projection in a first modified example.

FIG. 13 is a graph showing a relationship between an angle ψ and a notch depth h in the first modified example.

[Explanation of symbols]

 A1 Piezoelectric actuator, 10 Vibration plate, 17 Projection (end, projection), 18 Adjustment unit, 11, 12 Piezoelectric element, 13 Reinforcement plate (reinforcement), 30 …… Rotor (drive target), 70… Base plate (support).

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Makoto Furuhata 3-3-5 Yamato, Suwa City, Nagano Prefecture Inside Seiko Epson Corporation (72) Inventor Tsukasa Funasaka 3-5-5 Yamato, Suwa City, Nagano Prefecture Seiko Epson F term in reference (reference) 5H680 AA00 BB15 BC02 CC02 DD01 DD15 DD23 DD53 DD82 DD85 DD92 EE10 EE12 EE20 FF33 GG02 GG23 GG24 GG27

Claims (6)

[Claims] 1. A vibration plate in which a support, a plate-shaped piezoelectric element having a longitudinal direction, and a reinforcing portion are laminated, the diaphragm being supported so as to be able to vibrate on the support, An adjustment method for adjusting a driving characteristic of a piezoelectric actuator that drives a driving object that is in contact with an end portion on one end side in a longitudinal direction of the vibration plate, wherein the vibration plate is attached to a predetermined position, A driving characteristic of the piezoelectric actuator by changing a shape of the piezoelectric actuator. 2. The method for adjusting a piezoelectric actuator according to claim 1, wherein the piezoelectric actuator comes into contact with the end by vibrating the diaphragm to move the end along an elliptical trajectory. The driving target is driven in a predetermined driving direction, and the shape of the diaphragm is changed so that the major axis direction of the elliptical orbit is adjusted to substantially match the predetermined driving direction. Adjustment method of the piezoelectric actuator. 3. The method for adjusting a piezoelectric actuator according to claim 1, wherein the shape of the vibration plate is changed by deleting a part of the vibration plate. Adjustment method. 4. The method for adjusting a piezoelectric actuator according to claim 1, wherein the diaphragm has a protrusion protruding from the end, and the driving characteristics of the piezoelectric actuator are changed by changing a shape of the protrusion. A method for adjusting a piezoelectric actuator, comprising adjusting. 5. A vibration plate in which a support, a plate-shaped piezoelectric element having a longitudinal direction, and a reinforcing portion are laminated, wherein the vibration plate is supported so as to be capable of vibrating with respect to the support, A driving unit provided on one end side in the longitudinal direction of the plate and brought into contact with a driving target; and vibrating the diaphragm to move the driving unit along an elliptical orbit, thereby contacting the driving unit. A piezoelectric actuator that drives the contacted drive target in a predetermined drive direction, wherein the diaphragm includes an adjustment unit having a higher density than the reinforcing unit. 6. A vibrating plate in which a support, a plate-shaped piezoelectric element having a longitudinal direction, and a reinforcing portion are laminated, wherein the vibrating plate is supported so as to be able to vibrate on the support, A driving unit provided on one end side in the longitudinal direction of the plate and brought into contact with a driving target; and vibrating the diaphragm to move the driving unit along an elliptical orbit, thereby contacting the driving unit. A piezoelectric actuator that drives the contacted drive target in a predetermined drive direction, wherein the diaphragm includes an adjustment unit having a lower yield stress than the reinforcing unit.