JPH0416029B2 - - Google Patents

Abstract

PURPOSE:To facilitate housing a structure in which ribbon shape metal plates and piezoelectric plates are alternately laminated into a case as it is by a method wherein grooves are provided along the longitudinal direction of the case and the bent parts of the ribbon shape metal plates, which are to be electrode plates, are inserted into the grooves. CONSTITUTION:After a piezoelectric plate 10 is set on the first metal plate 11, the second metal plate 12 is set on the upper surface of the piezoelectric plate 10. Then, after the other piezoelectric plate 10 is set on the second metal plate 12, the first metal plate 11 is bent at the bent parts 11a and four plates are laminated. This laminated unit A is housed into a resin case 13 which has a cylindrical circumference altogether. As the bent parts 11a and 12 a of the metal plates 11 and 12 are inserted into the grooves 13a of the case 13 and the circumference of the piezoelectric plates 10 are fixed from four directions by the inner walls of the case 13, even if required voltage and frequency are applied to the laminated piezoelectric unit, relative positions between the piezoelectric plate 10 and the metal plates 11 and 12 are not varied.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a laminated piezoelectric body that is formed by laminating a large number of plate-like members made of piezoelectric elements, and expands and contracts in response to applied voltage.

[Conventional technology]

BACKGROUND ART Conventionally, a laminated piezoelectric body has been devised in which electrode plates made of ribbon-shaped metal plates and piezoelectric plates are alternately laminated. However, it is difficult for such a laminated piezoelectric body to maintain an integral structure simply by laminating them, and the relative position of the electrode plate and piezoelectric plate changes due to vibrations during driving, etc.
There were also problems such as the electrode plates coming into contact with each other and causing shoots.

[Problem that the invention seeks to solve]

The present invention has been made in view of the above-mentioned points, and its purpose is to prevent the relative relationship between the electrode plate and the piezoelectric plate even when the laminated piezoelectric body is driven under any conditions, such as when external vibrations or the like act. An object of the present invention is to provide a laminated piezoelectric material that can maintain an integral structure well without changing its physical position.

[Means for solving problems]

In the present invention, a plurality of piezoelectric plates and bendable first and second ribbon-shaped metal plates are alternately laminated and laminated to form a laminate, and the laminate is housed in a case. The inner wall of the case is characterized in that a groove is provided along the longitudinal direction of the case so that the bent portion of the ribbon-shaped metal plate can be inserted therein.

[Effect]

According to the configuration of the present invention, since the bent portion of the ribbon-shaped metal plate serving as the electrode plate is inserted into the groove provided along the longitudinal direction of the case, the ribbon-shaped metal plate and the piezoelectric plate are alternately overlapped. The laminated structure is stored in the case and the integrated structure can be maintained in good condition.

〔Example〕

Next, embodiments of the present invention will be described based on the drawings.

1 to 6 show a first embodiment of the present invention, in which FIG. 1 is a longitudinal sectional view of the laminated piezoelectric body, FIG. 2 is a top view of the laminated piezoelectric body, and FIG. The figure is a plan view of the ribbon-shaped metal plates before lamination, Figure 4 is a diagram used to explain when piezoelectric plates and ribbon-shaped metal plates are laminated, Figure 5 is a front view of the case, and Figure 6 is a diagram of the case. FIG.

Silver electrodes (not shown) with a diameter of 13 mm are concentrically formed on both sides of a plurality of piezoelectric plates 10, which are piezoelectric elements formed into discs with a diameter of 15 mm and a thickness of 0.5 mm. The first and second metal plates 11 and 12 for voltage application shown in FIG. 3 have ribbon shapes in which bent portions 11a and 12a are periodically formed by notching. For example, a stainless steel plate with a thickness of about 20 μm is used. These plural piezoelectric plates 1
0 and the first and second metal plates 11 and 12 are alternately superposed and laminated to form a laminate A shown in FIG.

Next, to explain in detail the laminated state of this laminate A, first, the piezoelectric plate 10 is set on the first metal plate 11, and then the second metal plate 12 is set on the top surface of the piezoelectric plate 10. , then another piezoelectric plate 10
After setting the first metal plate 11 on the second metal plate 12, the first metal plate 11 is bent at the bending portion 11a and stacked. This is shown in the state in the middle of lamination in FIG. 4. After the piezoelectric plate 10 is set, the metal plate 12 is bent backward in the figure from the bent part 12a (the state shown in FIG. 3), and then another layer is placed on top of it. After the piezoelectric plate 10 is set, the metal plate 11 is bent to the right from the bending portion 11a. After setting another piezoelectric plate 10, the metal plate 1
I layered them alternately by folding 2 toward the front. On the outer periphery of the piezoelectric plate 10 of the laminate A laminated in this way, first and second metal plates 11, 1
Part of the bent parts 11a and 12a of No. 2 is 0.5 at the center.
They protrude by less than mm and are arranged in four rows in the axial direction. At this time, the bent portions 11a, 12
It is preferable that the rows a are arranged alternately on the outer periphery of the laminate A at equal intervals.

This laminate A is integrally housed in a resin case 13 having a cylindrical outer periphery to form a laminate piezoelectric body shown in FIGS. 1 and 2.

The case 13 has a cylindrical shape by fixing a pair of semi-cylindrical cases as shown in FIGS. 5 and 6. The inner circumference of this case 13 has almost the same shape as the outer diameter of the piezoelectric plate 10, and a groove 13a with a depth of about 0.5 mm is provided at the center along the longitudinal direction. When fixed together, the groove 13a forms the bent portions 11a, 1 of the metal plates 11, 12.
2a becomes the groove into which it is inserted. Further, stopper portions 13b for maintaining the stacked body A are integrally formed at the upper and lower end portions of the case 13. Stopper part 13
b is located between the four grooves 13a on the inner periphery of the case 13, protrudes inward by about 1 mm, and holds the outer periphery of the piezoelectric plates 10 at the bottom and top stages.

Further, a voltage is applied to the first metal plate 11 and the second metal plate 12 via respective lead wires 14 and 15. The lead wires 14 and 15 are taken out to the outside through a small hole 13c provided in the case 13, and the small hole 13 is sealed with a grommet or the like.

Both lead wires 1 of the laminated piezoelectric body having such a configuration
When a voltage of 500 to 700 V is applied to the piezoelectric plates 4 and 15 in the polarization direction of the piezoelectric plate 10, they expand and contract by 50 to 70 microns in the axial direction, thereby acting as actuators.

The laminated piezoelectric body produced in this way has a laminated body A of a piezoelectric plate 10 and metal plates 11 and 12 in a case 1.
By housing it within 3, it is possible to maintain an integral structure. Furthermore, the bent portions 11 of the metal plates 11 and 12
a, 12a are inserted into the groove 13a of the case 13, and the outer periphery of the piezoelectric plate 10 is fixed from four directions by the inner wall of the case 13, so the laminated piezoelectric body is driven by applying a desired voltage and frequency. Even when the piezoelectric plate 10 and the metal plates 11, 12 are damaged due to vibration etc.
No movement of relative position occurs. Therefore, problems such as shot occurring between the two poles (metal plates 11 and 12) can be solved. Furthermore, since the laminated piezoelectric body having the above structure has a simple structure, manufacturing costs can be reduced. Furthermore, since the laminate A is all housed in a resin case, it has the advantage that it can be used as is in the housing of various actuators, such as injectors (fuel injection valves), switching valves, etc. have

In the above embodiment, the ribbon-shaped metal plates 11 and 12
Although we used a stainless steel plate with a thickness of 20 μm, the material and thickness can be changed depending on the application. Can be increased by 10%. The pair of cases 13 can be fixed together by taping, gluing, fitting, or the like.

Next, a second embodiment will be described based on FIGS. 7 to 9.

The piezoelectric plate 20 has a square shape, and the case 23 has a prismatic shape. Such a laminated piezoelectric body uses extremely simple ribbon-shaped metal plates as shown in FIG. 9 as the metal plates 21 and 22. , bending part 21
They are folded and stacked at points a and 22a in the same manner as in the previous embodiment. A bent portion 21 is provided on the inner wall of the case 23.
A groove 23a is formed into which the grooves 22a and 22a are inserted, and stopper portions 23b are provided at the upper and lower ends. Note that 24 and 25 are lead wires. Further, the piezoelectric plates 20 are stacked in the same manner as in the first embodiment and then housed in the case 23.

Therefore, the bent portions 21a, 2 of the metal plates 21, 22
Since the metal plate 2a is inserted and held in the groove 23a of the case 23, even when the laminated piezoelectric body is driven, the metal plate 2
1 and 22 do not shift, and no shot occurs between the electrodes. Furthermore, these metal plates 21, 22
Since the shape is an extremely simple ribbon shape, irregularities such as burrs do not occur during processing of the metal plates 21 and 22. Therefore, even if a high voltage load is applied to the laminated piezoelectric body manufactured using the metal plates 21 and 22 in its axial direction, no unreasonable stress is generated on the piezoelectric plate 20. There is also the advantage that there is no possibility of cutting or the like.

Next, FIG. 10 shows a third embodiment. FIG. 10 shows a structure in which a long hole 23d is provided on the outer circumferential side of the case 23 used in the second embodiment, and the other features are the same as in the second embodiment. By providing the elongated hole 23d in this way, the heat generated when the laminated piezoelectric body is driven can be radiated to the outside of the case 23, so that the durability of the laminated piezoelectric body can be improved. In addition, the hole 23d may be a long hole, many circular holes, or a square hole.
Needless to say, it is sufficient if the holes are such that some of the piezoelectric plate 20 and metal plates 21 and 22 inside the case 23 directly come into contact with the fluid (air or oil) outside the case 23.
Further, the case 13 of the first embodiment may also be provided with a similar elongated hole.

In addition, in the above-mentioned embodiment, cases 13 and 2
3, stoppers 13b and 23b were provided at the upper and lower ends of the ring-shaped stopper member. may be fixed.

〔Effect of the invention〕

As described above, according to the configuration of the present invention, the bent part of the ribbon-shaped metal plate that becomes the electrode plate is inserted into the groove provided along the longitudinal direction of the case, so that the ribbon-shaped metal plate and the piezoelectric The structure in which the plates are alternately laminated and laminated is stored in the case, and the integrated structure can be maintained in good condition.

Furthermore, the metal plate and piezoelectric plate do not move even with vibrations caused by driving the laminated piezoelectric material, so
It also has the effect of improving durability.

[Brief explanation of drawings]

1 to 6 show a first embodiment of the present invention, in which FIG. 1 is a longitudinal sectional view of the laminated piezoelectric body, FIG. 2 is a top view of the laminated piezoelectric body, and FIG. The figure is a plan view of the ribbon-shaped metal plates before lamination, Figure 4 is a diagram used to explain when piezoelectric plates and ribbon-shaped metal plates are laminated, Figure 5 is a front view of the case, and Figure 6 is a diagram of the case. FIG. 7 to 9 show the second embodiment, FIG. 7 is a longitudinal cross-sectional view of the laminated piezoelectric body, FIG. 8 is a top view of the laminated piezoelectric body, and FIG. 9 is a view of the laminated piezoelectric body before lamination. FIG. 10 is a plan view of a ribbon-shaped metal plate and a side view of a laminated piezoelectric body showing a third embodiment. 10, 20...Piezoelectric plate, 11, 1221, 22
...Metal plate, 13, 23...Case, 11a, 1
2a, 21a, 22a...Bending portion, 13a, 23
a... Groove.

Claims (1)

[Claims] 1. A plurality of piezoelectric plates formed from piezoelectric elements;
a first ribbon-shaped metal plate and a second ribbon-shaped metal plate, the first and second ribbon-shaped metal plates are bent and inserted between predetermined piezoelectric plates;
The plurality of piezoelectric plates and the first and second ribbon-shaped metal plates are alternately superimposed and laminated to form a laminate, and the laminate is housed in a case,
A laminated piezoelectric body characterized in that an inner wall of the case is provided with a groove extending along the longitudinal direction of the case so that the bent portions of the first and second ribbon-shaped metal plates are inserted. 2. The laminated piezoelectric body according to claim 1, wherein the case is provided with a cooling hole that communicates between an inner wall and an outer wall of the case so as to cool the ribbon-shaped metal plate.