JP4570840B2 - Piezoelectric transformer - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a piezoelectric transformer used for various power sources such as a high-voltage power source such as an inverter, an ozonizer, and an ionizer for cold-cathode tube lighting, and an AC-AC converter and a DC-DC converter.
[0002]
[Prior art]
The conventional general piezoelectric transformer shown in FIG. This piezoelectric transformer includes an elongated rectangular plate-like piezoelectric plate 101 such as PZT (lead zirconate titanate). A primary electrode 102 is provided on the surface of the piezoelectric plate 101, a primary electrode 103 is provided on the back surface, and a secondary electrode 104 is provided at an end of the surface of the piezoelectric plate 101. Further, as indicated by the arrows, the primary side is polarized with a high electric field in the thickness direction to form a drive unit, and the secondary side is polarized in the length direction to form a power generation unit. In the figure, L indicates the total length of the piezoelectric transformer, and W indicates the width. The piezoelectric plate 101 is housed in the transformer case 110.
[0003]
When a voltage having a natural resonance frequency determined by the dimension L is applied to the primary electrodes 102 and 103 of such a piezoelectric transformer, mechanical vibration is generated in the piezoelectric plate 101 due to the inverse piezoelectric effect. Further, a high voltage corresponding to the vibration is generated in the secondary electrode 104 due to the piezoelectric effect.
[0004]
Usually, a lead wire (not shown) for applying a voltage is soldered to the primary electrodes 102 and 103, and a lead wire (not shown) for taking out the voltage is soldered to the secondary electrode 104. Have been.
[0005]
[Problems to be solved by the invention]
However, the conventional piezoelectric transformer has the following problems. That is, the lead wire for taking out the voltage is soldered to the secondary electrode 104 of the piezoelectric transformer. For this reason, there is a problem that the soldered portion that has been soldered becomes a vibration load and induces vibrations other than the operation mode. In addition, vibration other than the operation mode may cause a decrease in efficiency and abnormal heat generation.
[0006]
An object of the present invention is to provide a piezoelectric transformer that solves the above-described problems and prevents the induction of vibrations other than the operation mode.
[0007]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the invention of claim 1 is directed to a piezoelectric transformer in which a connecting portion for inputting / outputting to the outside and / or a holding portion for holding a main body are provided on a primary side electrode and a secondary side electrode. In order to balance vibration with respect to the part and / or the holding part, a load part provided at a position different from the connection part and / or the holding part is provided, and the load part is provided with a weight provided on the piezoelectric plate. der is, and the primary electrodes having a lead wire is provided on the upper and lower surfaces of the piezoelectric plate, that the electrode having a lead wire only on one surface of the piezoelectric plate is provided on the secondary side This is a featured piezoelectric transformer.
[0008]
According to a second aspect of the present invention, in the piezoelectric transformer according to the first aspect, the load portion is a solder attached to the primary side electrode and / or the secondary side electrode.
[0009]
According to a third aspect of the present invention, in the piezoelectric transformer according to the first aspect, at least one of the input and output sides of the piezoelectric plate is laminated.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described in detail with reference to the drawings.
[0011]
[Embodiment 1]
A piezoelectric transformer according to this embodiment is shown in FIG. The piezoelectric transformer in FIG. 1 includes a piezoelectric plate 1, primary electrodes 2 and 3, and secondary electrodes 4 and 5. The piezoelectric plate 1, the primary electrodes 2 and 3, and secondary electrode 4, a piezoelectric plate 101 of FIG. 8, the primary electrodes 102 and 103, and since the secondary electrode 104 are respectively the same, description thereof will be omitted. The piezoelectric plate 1 is fixed to the transformer case (not shown) by the holding portion, similarly to FIG. 8, it is housed in the transformer case.
[0012]
One end portions of the lead wires 2B and 3B are connected to the primary electrodes 2 and 3 provided on the front and back surfaces of the piezoelectric plate 1 by solders 2A and 3A, respectively, to form primary-side input wiring portions. Similarly, one end portion of a lead wire 4B is connected to the secondary electrode 4 provided on one surface of the piezoelectric plate 1, that is, the surface in the illustrated example, by solder 4A.
[0013]
The secondary electrode 5 is provided at the end of the back surface of the piezoelectric plate 1 so as to face the secondary electrode 4, that is, at a position symmetrical to the secondary electrode 4 with respect to the piezoelectric plate 1. The secondary electrode 5 has the same shape as the secondary electrode 4. Similar to the secondary electrode 4, solder 5 </ b> A is attached to the secondary electrode 5. The weight of the solder 5A is substantially the same as that of the solder 4A.
[0014]
The solder 5A of the secondary electrode 5 on the back side acts as a load portion for balancing the solder 4A of the secondary electrode 4 on the front side. That is, when a voltage having a natural resonance frequency is applied to the primary electrodes 2 and 3 and the end portion of the piezoelectric plate 1 vibrates, the secondary electrode 4 portion to which the solder 4A is attached becomes a vibration load. In order to cancel out this vibration load, the secondary electrode 5 to which the solder 5A is attached balances the vibration operation and can prevent the vibration other than the operation mode from being induced. As a result, it is possible to prevent a decrease in efficiency and abnormal heat generation.
[0015]
Furthermore, according to the conventional piezoelectric transformer, as shown in FIG. 2A, distortion M is generated in the impedance characteristic due to the vibration load. However, according to the piezoelectric transformer according to this embodiment, the weight is balanced by the secondary electrode 5 to which the solder 5A is attached. Therefore, as shown in FIG. 2B, distortion occurs in the characteristic impedance. Can be prevented.
[0016]
[Embodiment 2]
In this embodiment, instead of the secondary electrode 5 with the solder 5A used in the first embodiment, the following is performed. As shown in FIG. 3, the weight 11 is adhered to the back surface of the piezoelectric plate 1 by the adhesive 12 so as to face the secondary electrode 4, that is, at a position symmetrical to the solder 4 </ b> A with respect to the piezoelectric plate 1. Yes. The weight 11 is almost the same as the solder 4A. As a substitute for the weight 11, any material having a weight such as metal can be used.
[0017]
The weight 11 bonded to the piezoelectric plate 1 acts as a load portion for balancing the solder 4A of the secondary electrode 4. When the voltage of the natural resonance frequency is applied to the primary electrodes 2 and 3 and the end of the piezoelectric plate 1 vibrates, the weight of the end of the piezoelectric plate 1 to which the weight 11 is attached is balanced. Induction of vibrations other than the operation mode can be prevented. As a result, it is possible to prevent a decrease in efficiency and abnormal heat generation.
[0018]
In this embodiment, the weight 11 is attached to the piezoelectric plate 1 by the adhesive 12. However, the weight 11 may be integrally sintered to the piezoelectric plate 1 and the weight 11 may be attached to the piezoelectric plate 1.
[0019]
[Embodiment 3]
In this embodiment, the weight 11 used in the second embodiment is as follows. That is, as shown in FIG. 4, the weight 13 is bonded to the secondary side rear surface of the piezoelectric plate 1 by the adhesive 12. The attachment position of the weight 13 is deviated from the bonding position of the weight 11 of the second embodiment. Then, the weight 13 is made heavier than the weight 11 by the amount by which the attachment position of the weight 13 is displaced. As a substitute for the weight 13, any material having a weight such as metal can be used.
[0020]
The weight 13 bonded to the back surface of the piezoelectric plate 1 acts as a load portion for balancing the solder 4A of the secondary electrode 4. When the voltage of the natural resonance frequency is applied to the primary electrodes 2 and 3 and the end of the piezoelectric plate 1 vibrates, the weight is balanced by the weight 13 to prevent the induction of vibrations other than the operation mode. Can do. As a result, it is possible to prevent a decrease in efficiency and abnormal heat generation.
[0021]
[Embodiment 4]
In this embodiment, instead of the secondary electrode 5 with the solder 5A used in the first embodiment, the following is performed. That is, as shown in FIG. 5, the solder 21 is attached to the primary electrode 2 that is the surface on the primary side of the piezoelectric plate 1 so as to be symmetrical with the solder 4 </ b> A with respect to the center of the piezoelectric plate 1. The weight of the solder 21 is substantially the same as the solder 4A of the secondary electrode 4.
[0022]
The solder 21 of the primary electrode 2 acts as a load portion for balancing the solder 4A of the secondary electrode 4. When the voltage of the natural resonance frequency is applied to the primary electrodes 2 and 3 and the end portion of the piezoelectric plate 1 vibrates, the weight is balanced by the solder 21 to prevent the induction of vibrations other than the operation mode. Can do. As a result, it is possible to prevent a decrease in efficiency and abnormal heat generation.
[0023]
Although the solder 21 is used in the fourth embodiment, a weight may be used instead of the solder 21 as in the second embodiment. Similarly to the third embodiment, weights or solders having different weights may be provided on the primary electrode 2 at positions that are asymmetric with the solder 4A.
[0024]
[Embodiment 5]
In this embodiment, instead of the secondary electrode 5 with the solder 5A used in the first embodiment, the following is performed. That is, as shown in FIG. 6, the solder 22 is attached to the primary electrode 3 which is the back surface on the primary side of the piezoelectric plate 1 so as to be symmetrical with the solder 4 </ b> A with respect to the center of the piezoelectric plate 1.
[0025]
The solder 22 of the primary electrode 3 acts as a load portion for balancing the solder 4A of the secondary electrode 4. And when the voltage of the natural resonance frequency is applied to the primary electrodes 2 and 3 and the end of the piezoelectric plate 1 vibrates, the weight is balanced by the solder 22 to prevent the induction of vibrations other than the operation mode. Can do. As a result, it is possible to prevent a decrease in efficiency and abnormal heat generation.
[0026]
Although the solder 22 is used in the fifth embodiment, a weight may be used instead of the solder 22 as in the second embodiment. Similarly to the third embodiment, weights or solders having different weights may be provided on the primary electrode 3 at positions that are asymmetric with the solder 4A.
[0027]
Although the embodiments of the present invention have been described above, the specific configuration is not limited to these embodiments, and even if there is a design change or the like without departing from the gist of the present invention, include.
[0028]
For example, in the above-described embodiment, the piezoelectric plate having a single plate structure has been described. However, a piezoelectric plate having a thin plate-like internal electrode having a predetermined thickness is provided on either or both of the input and output sides. Of course, the present invention can be applied to a well-known laminated structure stacked in the direction.
[0029]
In the above embodiment, the lead wire is used as the primary side input wiring means. However, for example, spring-like phosphorous copper may be used. Moreover, in the said embodiment, although the lead wire was connected to the electrode with the solder, you may join a lead wire, for example using a conductive adhesive.
[0030]
In the above-described embodiment, the load portion is solder or weight, but a holding portion for fixing the piezoelectric plate to the transformer case may be used as the load portion.
[0031]
Furthermore, in the embodiment described above, as shown in FIG. 7 (a), has been described piezoelectric transformer operating in primary mode piezoelectric plate 41 is vibrated in the section 42, a piezoelectric transformer which operates in multimode, for example, as shown in FIG. 7 (b), the piezoelectric plate 43 knots 44A, in the secondary mode of vibration at 44B, it is possible to apply the present invention.
[0032]
【The invention's effect】
As described above, according to the piezoelectric transformer of the present invention , since the load portion for balancing is provided, a structure that does not induce unnecessary vibration in the basic vibration mode, or a structure that cancels unnecessary vibration Can be. As a result, it is possible to prevent the occurrence of efficiency reduction and abnormal heat generation.
[Brief description of the drawings]
1A and 1B are diagrams showing a piezoelectric transformer according to a first embodiment, in which FIG. 1A is a front view, FIG. 1B is a rear view, and FIG. 1C is a side view.
2A and 2B are diagrams illustrating impedance characteristics, where FIG. 2A is a diagram illustrating impedance characteristics of a conventional piezoelectric transformer, and FIG. 2B is a diagram illustrating impedance characteristics according to Embodiment 1;
3A and 3B are diagrams showing a piezoelectric transformer according to a second embodiment, where FIG. 3A is a front view, FIG. 3B is a rear view, and FIG. 3C is a side view.
4A and 4B are diagrams showing a piezoelectric transformer according to a third embodiment, where FIG. 4A is a front view, FIG. 4B is a rear view, and FIG. 4C is a side view.
5A and 5B are diagrams showing a piezoelectric transformer according to a fourth embodiment, where FIG. 5A is a front view, FIG. 5B is a rear view, and FIG. 5C is a side view.
6A and 6B are diagrams showing a piezoelectric transformer according to a fifth embodiment, where FIG. 6A is a front view, FIG. 6B is a rear view, and FIG. 6C is a side view.
FIG. 7 is a side view for explaining a multi-order mode.
FIG. 8 is a perspective view showing a conventional example.
[Explanation of symbols]
1 Piezoelectric plate 2, 3 Primary electrode 2A, 3A Solder 2B, 3B Lead wire 4, 5 Secondary electrode 4A, 5A Solder 4B Lead wire 11, 13 Weight 12 Adhesive 21, 22 Solder
4 1, 43 Piezoelectric plate 42, 44A, 44B Section M Distortion

Claims (3)

In a piezoelectric transformer in which a connecting portion for inputting / outputting to the outside and / or a holding portion for holding the main body is provided on the primary side electrode and the secondary side electrode, the vibration is balanced against the connecting portion and / or the holding portion. for, with the load section provided in the connecting portion and / or the holding portion and the different positions, the load unit Ri weight der disposed on the piezoelectric plate, and the primary side upper and lower surfaces of said piezoelectric plate An electrode having a lead wire is provided on the secondary side, and an electrode having a lead wire is provided only on one surface of the piezoelectric plate on the secondary side .   2. The piezoelectric transformer according to claim 1, wherein the load portion is solder attached to the primary side electrode and / or the secondary side electrode.   2. The piezoelectric transformer according to claim 1, wherein at least one of input and output sides of the piezoelectric plate is laminated.

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