JP2002026415A - Piezoelectric transformer and mounting method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve reliability against vibration and impact by rigidly supporting/fitting a piezoelectric transformer which uses a profile expansion vibration mode to a substrate and the like. SOLUTION: A through hole is provided at the central part of a vibration node of a piezoelectric transformer, in which a support/fixing axis is inserted, and further the support/fixing axis is planted to a substrate and the like to fix the piezoelectric transformer. An elastic material which follow vibration of the piezoelectric transformer is inserted between the substrate and the like and the piezoelectric transformer for more rigid support and fixing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk-shaped or polygonal-shaped piezoelectric transformer utilizing a contour expanding vibration mode, and a method of supporting and mounting the same.

[0002]

[Prior Art] Starting with portable televisions and notebook computers,
With the spread of various portable electronic devices, piezoelectric transformers have been studied and put into practical use instead of electromagnetic transformers.
The piezoelectric transformer has a configuration in which a mechanical vibration is generated by applying an input voltage to a vibration unit, and the mechanical vibration is converted into a voltage in a power generation unit and output. Since no winding is required, it can be reduced in size and thickness, and has the characteristics that it does not generate electromagnetic noise with high efficiency.

Generally, the load resistance is several tens kΩ to several tens kΩ.
As a step-up liquid crystal backlight inverter transformer having a voltage of 0 kΩ, a type represented by a Rosen-type piezoelectric transformer whose output section has a high impedance is used.
FIG. 5 shows a Rosen-type piezoelectric transformer. The arrow in the figure is the direction of polarization. AC adapter or DC-D
For a power supply having a load of about several tens of ohms, such as a C converter, a structure in which a plurality of piezoelectric ceramic layers and a plurality of internal electrode layers are stacked so that the output section has low impedance is proposed and used.

FIGS. 6 and 7 show examples of a piezoelectric transformer having a structure in which a piezoelectric ceramic layer and an internal electrode layer are laminated.
7 shows an example using the thickness vertical effect, and FIG. 7 shows an example using the vertical-vertical effect type. A curve 61 in FIG.
Indicates a displacement distribution in the thickness direction. FIG. 8 shows an example of a piezoelectric transformer using a spreading vibration mode or the like.
8A shows a perspective view, and FIG. 8B shows a displacement distribution 81 and a stress distribution 82 in the cross section AA. Each of these piezoelectric transformers has a structure having a large capacity on the output side for matching with a load.

A laminated piezoelectric transformer utilizing a spreading vibration mode of a disc-shaped or polygonal-shaped piezoelectric ceramic is expected to be used in applications having a relatively small load impedance as described above, and has the most feasible structure. one of.

[0006]

In order to sufficiently realize the function of converting mechanical vibration into voltage in the piezoelectric transformer, the whole cannot be firmly supported and fixed. Only supported by the part. For this reason, a conventional electromagnetic transformer can be firmly soldered to a substrate by a land, whereas a piezoelectric transformer requires a special structure for a method of fixing to a substrate.

[0007] Among them, especially in the case of a spreading vibration transformer,
As shown in the displacement distribution in FIG. 8 (b), there is usually only one node (the point where the displacement is zero) used for the support in the center, and if the other parts are to be supported, the vibration is hindered, resulting in a large efficiency. There was a risk of causing a decrease.

[0008] For this reason, conventionally, a structure that supports only a central node portion has been tried. FIG. 9 shows an example of a central support structure. FIG. 9 (a) is a perspective view and FIG. 9 (b) is a side view. However, such a structure has insufficient vibration resistance and impact resistance. there were.

Accordingly, it is a technical object of the present invention to improve a method for supporting and fixing a piezoelectric transformer using a spreading vibration mode to a substrate or the like, and to secure reliability against vibration, impact, and the like.

[0010]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a structure for supporting and fixing a node part of vibration of a piezoelectric transformer utilizing contour-expanded vibration, and a substrate for reducing a factor inhibiting vibration. It was made as a result of studying the structure of attachment to the device.

That is, according to the present invention, in a method of mounting a piezoelectric transformer on a substrate utilizing a contour expanding vibration mode of a piezoelectric ceramic plate, the piezoelectric transformer is penetrated in a thickness direction for passing a supporting and fixing shaft through a center portion of the piezoelectric transformer. With a through hole,
This is a method for mounting a piezoelectric transformer, wherein the piezoelectric transformer is supported by implanting a support fixing shaft member through a through-hole into a substrate.

Further, the present invention provides the method for mounting a piezoelectric transformer according to the above method, wherein the substrate and the piezoelectric transformer are disposed between the substrate and the piezoelectric transformer, between the portion where the supporting and fixing shaft is planted on the substrate. A method for mounting a piezoelectric transformer, characterized in that an elastic body made of a polymer compound is interposed at least between the top and the top.

According to the present invention, there is provided a mounting method for accommodating a piezoelectric transformer utilizing a contour expanding vibration mode of a piezoelectric ceramic plate in a case in which the piezoelectric transformer is fitted. A piezoelectric transformer is mounted by providing a through-hole penetrating in a thickness direction for passing through, and supporting a piezoelectric transformer by implanting a supporting and fixing shaft member through the through-hole and enclosing the case in a case. .

Further, according to the present invention, in the above-described method for mounting a piezoelectric transformer, there is provided a method for mounting the support-fixing shaft member between the portion where the support-fixing shaft is implanted in the case and the piezoelectric transformer, and between the case and the case side of the piezoelectric transformer. A method for mounting a piezoelectric transformer, characterized in that an elastic body made of a polymer compound is interposed at least between the top and the top.

Further, the present invention is a piezoelectric transformer which is mounted on a substrate or a case by the above method.

[0016]

According to the supporting and fixing method of the present invention, the piezoelectric transformer can be moved in the horizontal direction in FIG. 9B by the impact as in the conventional supporting and fixing method shown in FIG. Will not jump out,
By providing a stopper in the vertical direction, the amount of movement in the same direction can be reduced to zero.

In the present invention, a polymer compound, particularly an elastomer, is interposed between the piezoelectric transformer and the substrate or the case, so that the substrate or the case and the piezoelectric transformer do not come into direct contact with each other. For this reason, it is possible to minimize the disturbance of the vibration of the piezoelectric transformer and the trouble due to the propagation of the vibration of the piezoelectric transformer to the device.

[0018]

Next, embodiments of the present invention will be specifically described with reference to the drawings. The piezoelectric transformer used in the present embodiment is a square having a side of 17.6 mm, a thickness of 6.0 mm, and is made of a high Qm piezoelectric ceramic material. An electrode of a silver-palladium alloy is formed inside, and layers adjacent to each other in the thickness direction of the input portion and the output portion are polarized in opposite directions.

The vibration mode of this piezoelectric transformer is shown in FIG.
This is a contour spreading vibration mode as shown in (b), in which the stress is maximum at the center and the displacement in the direction toward the outer periphery is zero. That is, this is a node. FIG.
In the four side portions in FIG. 2B, the stress is 0, but the displacement is maximum.

[0020]

Next, a specific mounting method of the piezoelectric transformer will be described.

(Embodiment 1) FIG. 1 is a view for explaining a method of supporting a piezoelectric transformer according to a first embodiment of the present invention.
1A is a perspective view, and FIG. 1B is a view showing a cross section of AA in FIG. 1A. A through-hole having a diameter of 1 mm is provided in the center of the piezoelectric transformer 10 to allow the shaft for supporting and fixing to pass therethrough.
Is inserted. A stopper 12 for preventing the piezoelectric transformer from coming off is provided above the shaft member.

Piezoelectric transformer 10 and supporting and fixing shaft 11
Are integrated by an adhesive. Also, the substrate 14
An elastic body 13 made of silicon rubber is inserted between the piezoelectric transformer 10 and the piezoelectric transformer 1.
0 is not directly contacted. The lower end of the supporting and fixing shaft 11 penetrating the piezoelectric transformer 10 is
4, whereby the entire piezoelectric transformer 10 and the substrate 14 are integrated. Here, a two-component reaction-curable silicone rubber is used as the silicone rubber, and the functions of the cushioning material and the adhesive are also provided.

FIG. 2 shows the frequency characteristic of the power transmission of the piezoelectric transformer of this embodiment. Curve 21 indicates the efficiency, curve 22 indicates the output voltage, and curve 23 indicates the temperature rise.
In the vicinity of the driving frequency of 120 kHz, when the maximum power transmission was 40 W, the efficiency was 97%, and the temperature rise at the center of the transformer was about 25 ° C.

(Embodiment 2) Next, a second embodiment of the present invention will be described. 3A and 3B are diagrams for explaining a method of indicating a piezoelectric transformer according to a second embodiment of the present invention. FIG. 3A is a perspective view, and FIG. 3B is a cross-sectional view taken along a line AA in FIG. FIG. The piezoelectric transformer 10 used is the same as in the first embodiment. In the first embodiment, a piezoelectric transformer 10 is formed by using a support fixing shaft 11 and through holes.
In this embodiment, the piezoelectric transformer is housed in a case 31 while the structure is fixed to the substrate 14.

Therefore, the supporting and fixing shaft 11 is implanted and fixed to both the central portion of the case 31 and a substrate (not shown). Further, in the first embodiment, the piezoelectric transformer 10 is supported and fixed only at the portion of the supporting / fixing shaft member 11, whereas in the present embodiment, the silicone adhesive is used at the corner of the case 31. The flexible elastic body 13 is supported and fixed in a form that can follow the vibration of the piezoelectric transformer 10.

Depending on the size and condition of the supporting and fixing portion, the vibration of the piezoelectric transformer may be hindered.
Special considerations are required. FIG. 4 shows the power transmission characteristics of the piezoelectric transformer in this embodiment. Also in this case, the curve 21 shows the efficiency, the curve 22 shows the output voltage, and the curve 23 shows the temperature rise. In this embodiment, the piezoelectric transformer is constrained at the four corners where the displacement of the piezoelectric transformer is maximized, although the piezoelectric transformer can follow the vibration to some extent.

For this reason, the transmission power slightly decreases, and when the maximum value of the amount of temperature rise is assumed to be 25 ° C., the power transmission is 33 W. And the maximum efficiency in this case is 9
5%, which is slightly lower than that of the first example. Similar reduction in power transmission was also observed when the piezoelectric transformer was directly mounted on the substrate and a silicon-based adhesive was interposed at the apex of the piezoelectric transformer on the substrate side.

[0028]

As described above, according to the piezoelectric transformer and the method of mounting the same according to the present invention, it is possible to practically use the contour expanding piezoelectric vibration transformer which can be firmly supported and fixed to a substrate or the like. .

[Brief description of the drawings]

FIGS. 1A and 1B are views showing a mounting method of a piezoelectric transformer according to a first embodiment of the present invention, FIG. 1A is a perspective view, and FIG.

FIG. 2 is a diagram showing power transmission characteristics of the piezoelectric transformer according to the first embodiment of the present invention.

FIGS. 3A and 3B are views showing a method for mounting a piezoelectric transformer according to a second embodiment of the present invention, FIG. 3A is a perspective view, and FIG.

FIG. 4 is a diagram showing power transmission characteristics of a piezoelectric transformer according to a second embodiment of the present invention.

FIG. 5 is a perspective view schematically showing a Rosen-type piezoelectric transformer.

FIG. 6 is a perspective view schematically showing a thickness vertical vibration type piezoelectric transformer.

FIG. 7 is a perspective view schematically showing a vertical-longitudinal vibration type piezoelectric transformer.

FIG. 8 is a view showing a spreading vibration mode piezoelectric transformer, and FIG.
(A) is a perspective view, FIG.8 (b) is a figure which shows a vibration mode.

FIG. 9 is a diagram showing an example of a conventional method of supporting a spreading vibration mode piezoelectric transformer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Piezoelectric transformer 11 Indicator shaft material 12 Stopper 13 Silicon rubber 14 Substrate 15 Output part 16 Insulating layer 17 Input part 21 Efficiency 22 Output voltage 23 Rising temperature 31 Case 61 Thickness direction displacement distribution 81 Displacement distribution 82 Stress distribution 91 Support fixing Parts

Claims (3)

[Claims] 1. A method of mounting a piezoelectric transformer on a substrate utilizing a contour expansion vibration mode of a piezoelectric ceramic plate, wherein a through hole is provided in a center portion of the piezoelectric transformer so as to pass through a shaft for supporting and fixing in a thickness direction. A piezoelectric transformer mounting method comprising: supporting a piezoelectric transformer by fixing a shaft member for supporting and fixing through a through hole. 2. The mounting method of a piezoelectric transformer according to claim 1, wherein a height is set at least between the fixed portion of the supporting and fixing shaft and the piezoelectric transformer and at least between the transformer and an outer peripheral portion. A method for mounting a piezoelectric transformer, wherein an elastic body made of a molecular compound is interposed. 3. A piezoelectric transformer mounted on a substrate or a case by the method according to claim 1.