JPS63194377A - Method and apparatus for driving laminated piezoelectric element - Google Patents

Abstract

PURPOSE:To improve reproducibility and the precision of the quantity of a laminated piezoelectric element displaced through a simple control method by properly selecting each piezoelectric element board, applying voltage, and controlling the quantity of the laminated piezoelectric element displaced on the basis of the total amount of the displacement of each piezoelectric element board to which voltage is applied. CONSTITUTION:A laminated piezoelectric element 11 is constituted by laminating twelve piezoelectric element boards P1-P12, and electrode sections Q1-Q13 are disposed onto the outer side surfaces of the piezoelectric element boards P1, P12 positioned at both outside sections and among respective piezoelectric element P1-P12 board. The voltage of a power supply 13 can be applied to each piezoelectric element board P1-P12 separately by properly selecting respective switch SW1s-SW6s, Sw1r-SW7r. Accordingly, since each piezoelectric element board P1-P12 is selected properly, voltage having the same voltage value is applied to the selected each piezoelectric element board respectively and the quantity D of the laminated piezoelectric element 11 displaced is controlled by the total amount of the quantity deltaof displacement of separate piezoelectric element board, which are all displaced to delta, the number of the piezoelectric element boards applied to the desired quantity D of displacement may be chosen, thus extremely simplifying control.

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Field of Industrial Application) The present invention relates to a method for driving a laminated piezoelectric element and an apparatus therefor.

(Prior Art) Conventionally, as shown in FIGS. 7 and 8, a laminated piezoelectric element 1
An internal electrode 3 is arranged between each piezoelectric element plate 2, and each internal electrode 3 is grouped every other, and the grouped electrodes are connected to a positive external electrode 4 and a negative electrode provided on the side surface of the laminated piezoelectric element. It had a structure connected to electrode 5. The same working part electrodes 4.5 of the laminated piezoelectric element 1 were connected to a power source via a voltage control circuit.

Then, based on the applied voltage-displacement characteristics of the laminated piezoelectric element 1 shown in FIG. The amount of displacement of 1 was controlled.

(Problems to be Solved by the Invention) However, since the displacement amount of the laminated piezoelectric element 1 is controlled by analog control of each piezoelectric element plate 2 at the same time,
The voltage control circuit becomes very complex and is easily influenced by noise, making it difficult to obtain a stable displacement amount due to noise.

In addition, since the drive control of this V4 type piezoelectric element 1 is performed in an open loop, the hysteresis is large and it is difficult to accurately measure the amount of displacement, as is clear from the applied voltage-displacement characteristics of the multilayer piezoelectric element 1 shown in FIG. There are problems in that it is difficult to control and that reproducibility decreases due to long-term repetition.

An object of the present invention is to provide a method and device for driving a laminated piezoelectric element, which solves the above-mentioned problems and can improve reproducibility with a simple control method and improve the accuracy of the displacement amount of the laminated piezoelectric element. It is in.

Structure of the Invention (Means for Solving Problems) In order to achieve the above object, the first invention comprises a plurality of piezoelectric element plates that are displaced in one direction when a voltage is applied and are laminated in the direction of displacement. In a laminated piezoelectric element, each piezoelectric element plate is provided with an electrode capable of applying a voltage to individually displace each piezoelectric element plate by a certain amount, and each of the piezoelectric element plates constituting the laminated piezoelectric element is The gist thereof is a method for driving a laminated piezoelectric element, in which a voltage selected as appropriate is applied, and the displacement m of the laminated piezoelectric element is controlled based on the cumulative total of the displacement of each applied piezoelectric element plate. It is.

A second invention provides a laminated piezoelectric element which is formed by laminating a plurality of piezoelectric element plates displacing in one direction when a voltage is applied, and piezoelectric element plates disposed on both outer sides of the laminated piezoelectric element. Electrode parts provided on the outer surface and between each piezoelectric element plate and serving as a positive electrode and a negative electrode every other, each electrode part of the positive electrode being connected to a positive terminal, and each electrode part of the negative electrode being connected to a negative terminal. a switching member provided between each of the electrode parts and each terminal of the power supply to connect and separate the electrode part and the terminal; and a piezoelectric element plate to be applied to a displacement amount of the laminated piezoelectric element. an indicating means for determining an electrode section to be used for applying a voltage to a piezoelectric element plate indicated by the indicating means from among the electrode sections; The gist of the present invention is a driving device for a laminated piezoelectric element, which comprises a driving means for turning on a switching member provided corresponding to an electrode portion.

A third invention provides a laminated piezoelectric element formed by laminating a plurality of piezoelectric element plates that displace in one direction when a voltage is applied, and piezoelectric element plates located on both outer sides of the laminated piezoelectric element. The electrode portions are provided on the outer surface and between each piezoelectric element plate and serve as a positive electrode and a negative electrode, respectively, and each electrode portion of the positive electrode is a positive terminal, and each electrode portion of the negative electrode is a negative terminal. a power supply connected to the
A switching member is provided between each electrode portion of the positive electrode and the positive terminal of the power source and connects and separates the electrode portion and the positive terminal, and a piezoelectric element plate is configured to apply an application to the amount of displacement of the laminated piezoelectric element. an indicating means, an indexing means for determining, from among the electrode sections of each of the positive electrodes, an electrode section to be used for applying a voltage to a piezoelectric element plate indicated by the indicating means; The gist of the present invention is a driving device for a laminated piezoelectric element, which comprises a driving means for turning on a switching member provided to an electrode portion of a positive electrode.

(Function) In the first invention, by appropriately selecting each piezoelectric element plate and applying a voltage, only the selected piezoelectric element plate can be displaced. Therefore, the number of piezoelectric element plates to which voltage is applied is By appropriately selecting , the amount of displacement of the laminated piezoelectric element can be controlled.

In the second invention, when the indicating means specifies the piezoelectric element plate to be applied for the amount of displacement of the laminated piezoelectric element, the indexing means is used to apply voltage to the specified piezoelectric element plate. The electrode portions of the positive and negative electrodes are indexed and switching members provided corresponding to the electrode portions are turned on via the driving means.

As a result, only each selected piezoelectric element plate can be displaced, and the laminated piezoelectric element can be displaced by a predetermined displacement amount.

In the third invention, when the indicating means specifies the piezoelectric element plate to be applied for the amount of displacement of the laminated piezoelectric element, the indexing means is used to apply a voltage to the specified piezoelectric element plate. An electrode portion of the electrode is indexed and a switching member provided corresponding to the electrode portion is turned on via a driving means.

As a result, only each selected piezoelectric element plate can be displaced, and the laminated piezoelectric element can be displaced by a predetermined displacement amount.

(Example) Hereinafter, an example embodying the present invention will be described based on the drawings.

In FIG. 1, the laminated piezoelectric element 11 is constructed by laminating 12 piezoelectric element plates P1 to P12, and
Electrode portions Q1 to Q13 are arranged between the outer surfaces of the piezoelectric element plates P1 and P12 on both outer sides and between the respective piezoelectric element plates P1 to P12.

Each electrode Q3. is provided every other electrode from the electrode portion Q1.
Q5. -Q7. Q9. Q11. The negative external electrodes R1 to R7 are attached to the front right corner of Q13, and the remaining electrode parts Q2. Q4. Q6゜Q8. Q10. Positive external electrodes 81 to S6 are attached to the left back corner of Q12. Each of the external electrodes R1 to R7 and S1 to S6 is connected to a drive circuit 12 as a drive means.

The drive circuit 12 is composed of switches such as transistors, relays, analog switches, etc. as switching members provided corresponding to the respective external electrodes, and each switch S provided corresponding to the positive external electrodes 81 to S6.
When W15-8W6s is turned on based on a drive signal from a control circuit 14 to be described later, the external electrodes S1 to S6 are electrically connected to the positive terminal of the power source 13. Further, when the switches 5W1r to 3W7r provided corresponding to the negative external electrodes R1 to R7 are turned on based on the drive signal from the control circuit 14, they are connected to the same external electrodes R1 to R7. ! ! It is designed to be electrically connected to the negative terminal of No. 13.

Therefore, each switch SW15-8W6s.

By appropriately selecting SWlr to 5W7r, the voltage of the power source 13 can be applied independently to each piezoelectric element plate P1 to P12. Then, the piezoelectric element plate to which the voltage is applied is displaced by a displacement amount δ with respect to the applied voltage of the power source 13 in the stacking direction.

Therefore, when a voltage is simultaneously applied to a plurality of piezoelectric element plates and each piezoelectric element is individually displaced by δ, the total number (accumulation) of each displacement amount δ becomes the displacement amount of the laminated piezoelectric element 11.

Moreover, the laminated piezoelectric element 11 has a displacement scale of 0 to 12.
The displacement ff1D can be increased or decreased in units of displacement position δ (hereinafter referred to as 1 step) between δ, that is, 13 displacements ff1D (including the case where the displacement ID is zero) can be selected.

The control circuit 14 serving as an instruction means and an indexing means selects a piezoelectric element plate to which a voltage is applied based on an external signal instructing the displacement ff1D of the laminated piezoelectric element 11, and applies a voltage to the selected piezoelectric element plate. This circuit determines the switch of the circuit 12, and outputs a drive signal to the drive circuit 12 to turn on the determined switch.

In this embodiment, for each displacement taD of the laminated piezoelectric element 11, each switch SW15-8W6s, SWI r ~5
A piezoelectric element plate to which voltage is applied by controlling W7r on and off as shown in FIG. 2 is selected.

Therefore, by sequentially applying voltage to the piezoelectric element P1 on the lower side in FIG. It is also possible to displace the displacement ID by several steps at once by controlling each switch as shown in FIG.

In this way, in this embodiment, each piezoelectric element plate P1 to P
12 is selected as appropriate, and a voltage having the same voltage value is applied to each selected piezoelectric element plate, and the displacement measurement of the laminated piezoelectric element 11 is controlled by the cumulative amount of displacement δ of each piezoelectric element plate that is all displaced by δ. Therefore, it is only necessary to select the number of piezoelectric element plates to be applied for the desired displacement fllD,
Control is much simpler than conventional analog control.

In addition, since the voltage applied to each piezoelectric element plate P1 to P12 is one preset voltage value, there is no need to change the voltage value of the applied voltage every time the displacement ff1D changes, unlike analog control. The circuit configuration becomes very simple, and the influence of hysteresis of each piezoelectric element plate P1 to P12 is much smaller than in analog control, allowing highly accurate displacement control, and repeatability is improved by long-term repetition. There is no such thing as a decline.

Next, a second embodiment of the present invention will be described with reference to FIGS. 3 and 4.

In this embodiment, the laminated piezoelectric cable 11 is composed of a laminated piezoelectric element 11 in which 13 piezoelectric element plates P1 to P13 are laminated,
Electrode portions 01- provided on each surface of each piezoelectric element plate P1-P13
Among Q14, each electrode Q3°Q5. is provided every other electrode from the lowest electrode portion Q1. ~． Q11. Negative external electrodes R1 to R7 are attached to the front right corner of Q13, and the remaining electrode parts Q2, Q4. ~． Q12. Positive external electrodes 81 to S7 are attached to the back left corner of Q14.

The positive external electrodes 81 to S7 are connected to the switches 5W1s to 8W7 provided in the drive circuit 12 as in the above embodiment.
It is electrically connected to the positive terminal of the power source 13 via s. On the other hand, negative external electrodes R1 to R7
is electrically connected directly to the negative terminal of the power source 13 so that it is always grounded.

For example, when displacing the laminated piezoelectric element 11 by δ, only the switch 5W7S is turned on, when displacing it by 2δ, only the switch 5W1s is turned on, and when displacing it by 3δ, the switch SW1S, 5
All you have to do is turn on two W7Ss. Therefore,
As shown in FIG. 4, by controlling the switches SW15-8W7s on and off, the displacement of the laminated piezoelectric element 11 can be appropriately controlled between 0 and 13δ, as in the previous embodiment.

In this way, in this embodiment, the same effects as in the previous embodiment can be obtained, and the negative external electrodes R1 to R7
Since it is directly electrically connected to the negative terminal of the power source 13, there is no need for switches corresponding to the negative external electrodes R1 to R7, which simplifies the circuit configuration of the drive circuit 12 and simplifies control accordingly.

Next, a third embodiment of the present invention will be described with reference to FIGS. 5 and 6.

In this embodiment, the laminated piezoelectric element 11 has 15 piezoelectric element plates P.
Electrode portions 01 to Q provided on each surface of each piezoelectric element plate P1 to P15 are composed of a laminated piezoelectric element 11 in which piezoelectric elements 1 to P15 are laminated.
16, each electrode Q14°Q12. is provided every other electrode from the uppermost electrode portion Q16. ~． Q4. Negative external electrodes R1 to R8 are attached to the front right corner of Q2, and each remaining electrode portion Ql.

Q3. ~． Q13. Positive external electrodes 81 to S8 are attached to the left back corner of Q15.

The negative external electrodes R1 to R8 are electrically connected directly to the negative terminal of the power source 13 and are always grounded. On the other hand, the positive external electrodes 81 to S7 are connected to each piezoelectric element plate P.
Switches 5W1s to 3W4 are respectively provided in the drive circuit 12 so that the piezoelectric element plates 1 to P15 are grouped and a voltage is simultaneously applied to each piezoelectric element plate succumbing to the group.
It is electrically connected to the positive terminal of the power source 13 via s.

In this embodiment, the switch 5W1s has an external electrode S1.
, the switch 5W2s is connected to the external electrode S2, and the switch 5W2s is connected to the external electrode S2.
3S is connected to external electrodes S3 and S4, and switch 5W4S is connected to external electrodes 85, 86, and 87 to divide each piezoelectric element plate P1 to P16 into four groups. In this case, the first group is the piezoelectric element plate P1, the second group is the piezoelectric element plate P2. P3, the third group is piezoelectric element plates P4 to P7, and the fourth group is piezoelectric element plates P8 to P7.
It becomes P16.

Therefore, for example, when displacing the laminated piezoelectric element 11 by δ, only the switch 5WIS is turned on and a voltage is applied to the piezoelectric element plate P1 of the first group, and when displacing the laminated piezoelectric element 11 by 2δ, only the switch 5W2S is turned on. let, second
The piezoelectric element plate P2 of the group P2. Apply voltage to P3,
Moreover, when displacing by 4δ, it is sufficient to turn on only the switch 5W3s and apply voltage to the piezoelectric element plates P4 to P7 of the third group.

Then, as shown in FIG. 6, each switch SW15-8W
By controlling 4s on and off, the displacement of the laminated piezoelectric element 11 can be appropriately controlled within the range of 0 to 16[delta], similar to the embodiment described above.

As described above, in this embodiment, the same effects as those in the first and second embodiments can be obtained, and each piezoelectric element plate is arranged so that the displacement scale of the laminated piezoelectric element 11 can be displaced between O and 16δ. Since P1 to P15 are each grouped and a voltage is applied to each piezoelectric element plate belonging to the group at the same time, the number of switches in the drive circuit 12 is further reduced, the circuit configuration of the drive circuit 12 is simplified, and the Control becomes easier.

Note that this invention is not limited to the above embodiments,
For example, the number of piezoelectric element plates may be 50 or more, or the number of piezoelectric element plates may be grouped into arbitrary numbers.
Of course, changes may be made as appropriate without departing from the spirit of the invention.

Effects of the Invention As detailed above, according to the present invention, a multilayer piezoelectric element can be made with excellent reproducibility, and
This has the excellent effect of increasing the accuracy of the displacement amount of the laminated piezoelectric element, and driving and controlling the laminated piezoelectric element with a very simple circuit configuration.

[Brief explanation of the drawing]

FIG. 1 is an electrical block circuit diagram showing the electrical configuration of a drive device for driving a laminated piezoelectric element embodying the present invention;
FIG. 2 is a diagram showing the relationship between the switch corresponding to each piezoelectric element plate and the displacement amount of the laminated piezoelectric element, and FIG. 3 is a diagram showing the relationship between the displacement amount of the laminated piezoelectric element and the switch corresponding to each piezoelectric element plate, and FIG. FIG. 4 is an electrical block circuit diagram showing the electrical configuration of the drive device for causing each piezoelectric element plate to move, FIG. FIG. 6 is an electric block circuit diagram showing the electrical configuration of a driving device for driving a laminated piezoelectric element for explaining three embodiments. FIG. ), FIGS. 7 and 8 are diagrams showing the electrode structure of a conventional laminated piezoelectric element, and FIG. 9 is a diagram showing the relationship between the voltage and hysteresis of the piezoelectric element. In the figure, 11 is a laminated piezoelectric element, 12 is a drive circuit, 13 is a power supply, 14 is a control circuit, P1 to P15 are piezoelectric elements, 01
~Q16 is the electrode part, R1-R8 is the negative external electrode, 8
1 to S8 are positive external electrodes, switch SWI S-8W
6s, SWI r to 5W7r are switches, and D and δ are variable positions. Patent applicant Toyota Industries Corporation Shikiri
Person Patent Attorney On 1) Hironobu Figure 1 Figure 4 Applied voltage m Figure 7 Figure 8

Claims (1)

[Claims] 1. In a laminated piezoelectric element formed by laminating a plurality of piezoelectric element plates that displace in one direction when a voltage is applied in the direction of displacement, each piezoelectric element plate constituting the laminated piezoelectric element: Each piezoelectric element plate is provided with an electrode capable of applying a voltage to individually displace it by a certain amount, and each piezoelectric element plate is appropriately selected and a voltage is applied to each piezoelectric element plate to which the applied voltage is applied. A method for driving a laminated piezoelectric element, in which an amount of displacement of the laminated piezoelectric element is controlled based on a cumulative total of displacements of the laminated piezoelectric element. 2. Each piezoelectric element plate constituting the laminated piezoelectric element is grouped into a predetermined number of groups, each group is selected as appropriate, and a voltage is applied to the piezoelectric element plate of each selected group. 2. The method of driving a laminated piezoelectric element according to claim 1, wherein the amount of displacement of the laminated piezoelectric element is controlled based on the cumulative total of displacements of the applied piezoelectric element plates. 3. The method for driving a laminated piezoelectric element according to claim 2, wherein each group is composed of groups of 1, 2, 4, . . . 2 piezoelectric element plates. 4. A laminated piezoelectric element formed by laminating a plurality of piezoelectric element plates that displace in one direction when a voltage is applied, in the direction of displacement, and outer surfaces of the piezoelectric element plates on both outsides of the laminated piezoelectric element, and An electrode part provided between each piezoelectric element plate and serving as a positive electrode and a negative electrode every other, and a power source connecting each electrode part of the positive electrode to the positive terminal and each electrode part of the negative electrode to the negative terminal. a switching member that is provided between each of the electrode sections and each terminal of the power source to connect and separate the electrode section and the terminal; and a switching member that directs a piezoelectric element plate to apply an application to the amount of displacement of the laminated piezoelectric element. an indicating means; an indexing means for determining an electrode section to be used for applying a voltage to a piezoelectric element plate designated by the indicating means from among the electrode sections; and an electrode determined by the determining means. A driving device for a laminated piezoelectric element, comprising a driving means for turning on a switching member provided in a corresponding position. 5. A laminated piezoelectric element formed by laminating a plurality of piezoelectric element plates that are displaced in one direction when a voltage is applied in the direction of displacement, and outer surfaces of the piezoelectric element plates on both outer sides of the laminated piezoelectric element. and electrode portions provided between each piezoelectric element plate, each serving as a positive electrode and a negative electrode, each electrode portion of the positive electrode being connected to the positive terminal, and each electrode portion of the negative electrode being connected to the negative terminal. a switching member provided between each electrode portion of the positive electrode and the positive terminal of the power source to connect and separate the electrode portion and the positive terminal; and a piezoelectric voltage applied to the amount of displacement of the laminated piezoelectric element. an indicating means for indicating an element plate; an indexing means for determining an electrode section to be used for applying a voltage to the piezoelectric element plate indicated by the indicating means from among the electrode sections of each of the positive electrodes; and the indexing means. A drive device for a laminated piezoelectric element, comprising a drive means for turning on a switching member provided for an electrode portion of a positive electrode determined by the means. 6. The electrode portions that serve as positive electrodes and negative electrodes are arranged such that the electrode portions provided on the outer surfaces of the piezoelectric element plates on both outer sides are different electrodes from each other. 6. A driving device for a laminated piezoelectric element according to item 5.