JPH02276280A - Piezoelectric laminated body - Google Patents

Abstract

PURPOSE:To prevent the penetration of moisture into a piezoelectric laminated body of this design so as to enhance it in resistance to an organic solvent or the like by a method wherein an insulating layer containing at least one of epoxy resin, silicone rubber, a thermally shrinkable tube, an adhesive agent is formed in close contact with the peripheral side face of two or more laminat ed piezoelectric plates which expand or shrink when a voltage is applied. CONSTITUTION:A piezoelectric plate 1 expands or shrinks when a voltage is applied between lead wires 2. An insulating layer 3 is formed on the outer periphery of the piezoelectric plate 1 in a following process: first of all, the outer peripheral face of the piezoelectric plate 1 is adjusted in roughness and subjected to a treatment that the lead wires 2 are easily bonded; then, a degreasing treatment is carried out to the face concerned using a solvent such as trichlene or the like; and the face is dried up and then the insulating layer 3 is formed thereon through a potting method. Then, the insulating layer 3 is brought into close contact with a part of the piezoelectric plate 1 and the lead wires 2 through baking or curing. The insulating layer 3 is formed of epoxy resin, silicone rubber or the like. The periphery of the insulating layer 3 may as well be firmly coated with a thermally shrinkable tube 4.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a piezoelectric laminate, and particularly to a piezoelectric laminate with improved durability.

[Conventional technology]

An example of a conventional piezoelectric laminate is JP-A-62-
There is a publication No. 299094. The piezoelectric laminate disclosed in this publication has a resin case containing a piezoelectric plate, a metal plate, and a dummy plate inside, and a heat-shrinkable tube that shrinks when heat is applied to the outer periphery of the resin case is fitted. .

[Problems to be Solved by the Invention] In the piezoelectric laminate having the above structure, there is a gap between the piezoelectric laminate body (piezoelectric plate) and the surrounding resin case, so moisture, etc. may enter the interior through the gap. This will cause a short circuit and the piezoelectric plate will not be able to operate.

Furthermore, when a voltage is applied to a piezoelectric plate, it expands and contracts, and during this expansion and contraction (when electrical energy becomes mechanical energy) heat is generated, increasing the temperature of the piezoelectric plate.

[Means to solve the problem]

According to the present invention, the above-mentioned problem is solved by applying an adhesive such as epoxy resin, silicone rubber, heat shrinkable tube, or adhesive to the outer peripheral side of the piezoelectric plate, which is made of a piezoelectric material and expands or contracts when a voltage is applied. The problem is solved by a piezoelectric laminate characterized by closely forming an insulating layer containing at least one type of insulating layer.

In particular, in the present invention, it is more preferable that a highly thermally conductive metal thin plate is adhered to the outer peripheral side surface of the insulating layer.

[For production]

That is, according to the present invention, since epoxy resin, silicone rubber, etc. are closely formed on the outer peripheral side surface of the piezoelectric plate, the resistance against the external environment is increased.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

FIGS. 1(a) and 1(b) are a cross-sectional view and a vertical cross-sectional view, respectively, showing the first embodiment.

In FIG. 1, l is a piezoelectric plate (laminated body) 1 in which a plurality of PZT-based piezoelectric bodies are laminated. 2 is a lead wire coated with vinyl chloride, silicone rubber, Teflon, etc. for applying voltage to the piezoelectric laminate. These lead wires 2 are connected to predetermined positions on the side surface of the piezoelectric plate 1 by soldering, welding, or the like.

By applying a voltage between the lead wires 2, the piezoelectric plate 1 expands and contracts. An insulating layer 3 is formed on the outer periphery of the piezoelectric plate 1, and the formation process is such that the surface roughness of the outer periphery of the piezoelectric plate 1 is first adjusted and the lead wires 2 are treated to facilitate adhesion, and then an organic solvent such as trichlene is applied. After degreasing and drying, it is formed by a casting method (other methods such as dip methods are also available). Thereafter, baking or carrying is performed to bring the insulating layer 3 into close contact with the piezoelectric plate 1 and a portion of the lead wire 2. As the material of the insulating layer 3, epoxy resin, silicone rubber, etc., which have excellent environmental resistance, are used.

By bringing the insulating layer 3 into close contact with the piezoelectric laminate body in this way, it is possible to prevent moisture from entering the vicinity of the piezoelectric plate 1, so the piezoelectric laminate can be used even in high-temperature atmospheres and underwater (in liquids containing water). .

Next, a second embodiment will be described.

FIGS. 2(a) and 2(b) are a cross-sectional view and a vertical cross-sectional view, respectively, showing the second embodiment.

The second embodiment is obtained by adding a heat shrinkable tube 4 to the process of the first embodiment. That is, the tube 4 is firmly attached around the insulating layer 3. The material used for this heat shrink tube is vinyl chloride, silicone rubber, Teflon, or the like. By doubly covering the outer periphery of the piezoelectric plate in this manner, it becomes more robust against the external environment.

Next, a third embodiment will be described.

FIGS. 3(a) and 3(b) are a cross-sectional view and a vertical cross-sectional view, respectively, showing the third embodiment.

The third embodiment is an example in which the interface between the insulating layer 3 and the heat shrinkable tube 4 shown in the second embodiment is bonded with an adhesive 5. By applying the adhesive 5 to the boundary surface in this way, it is possible to reliably prevent moisture from entering.

It is desirable that the material of the outermost heat-shrinkable tube 4 be treated to facilitate adhesion.

Next, a fourth embodiment will be explained.

FIGS. 4(a) and 4(b) are a cross-sectional view and a vertical cross-sectional view, respectively, showing the fourth embodiment.

The fourth example is the adhesive 5 of Example 3 shown in FIG.
This is an example in which a is applied only to both ends, and this method can simplify the manufacturing process of the third embodiment.

Next, a fifth embodiment will be described.

FIGS. 5(a) and 5(b) are a cross-sectional view and a vertical cross-sectional view, respectively, showing the fifth embodiment.

In this embodiment, the outer periphery of the piezoelectric plate 1 is covered with a heat-shrinkable tube 4 made of vinyl chloride, silicone rubber, Teflon, etc., and only the tube 4 is bonded with an adhesive 6. This structure is suitable for those in which the electric field strength of the driving voltage of the piezoelectric plate l is relatively low.

Next, a sixth embodiment will be described.

In the sixth embodiment, as shown in FIGS. 6 and 7, the outer periphery of the insulating layer 3 of the piezoelectric plate 1 shown in the first embodiment is
A thin plate material 6 with good thermal conductivity, such as an Affi plate, was tightly wound. FIG. 8 shows the temperature distribution of the piezoelectric plate 1 when the piezoelectric plate 1 shown in FIG. 1 is activated by a solid line A, and the temperature distribution when the piezoelectric laminate shown in FIGS. The temperature distribution of the piezoelectric plate is shown by a broken line B. In the sixth embodiment, the maximum value of the surface temperature distribution of the piezoelectric laminate (particularly in the center) is lower than in the first embodiment, and a nearly uniform temperature distribution can be achieved.

As a result, the durability is lXl0”→lX compared to the conventional structure.
10". Furthermore, the surface temperature of the overlapping portion of the thin plates on the outer periphery of the insulating layer can be made more uniform by contacting them by soldering or the like.

Next, a seventh embodiment will be described.

FIGS. 9(a) and 9(b) are a cross-sectional view and a vertical cross-sectional view, respectively, showing the seventh embodiment.

As shown in FIGS. 9(a) and 9(b), in the seventh embodiment, a cylinder 6a made of a thin plate such as a copper plate or an Al plate with good thermal conductivity is placed around the outer periphery of a piezoelectric plate 1 with a certain gap. Then, an epoxy or acrylic adhesive, for example, was injected into the gap, solidified, and integrated. When injecting the adhesive into the gap, the pressure was reduced to prevent air from being entrained. The piezoelectric laminate thus produced was operated and its surface temperature was measured. As a result, the temperature distribution was the same as in Example 6, and the durability was also the same.

〔Effect of the invention〕

As explained above, according to the present invention, moisture intrusion is prevented by closely molding the insulating layer around the outer periphery of the piezoelectric laminate, and in particular, since the piezoelectric laminate is covered with metal foil, etc., the resistance of the piezoelectric laminate to organic solvents, etc. is increased. do.

[Brief explanation of drawings]

FIGS. 1(a) and (b) are a partial cross-sectional view and a vertical cross-sectional view, respectively, showing a first embodiment, and FIGS. 2(a) and (b) are a partial cross-sectional view, respectively, showing a second embodiment. FIGS. 3(a) and 3(b) are a partial cross-sectional view and a longitudinal sectional view, respectively, showing the third embodiment; FIGS. 4(a) and (b) are a partial cross-sectional view and a longitudinal cross-sectional view, respectively, showing the fourth embodiment, and FIGS. 5(a) and (b) are a partial cross-sectional view and a longitudinal cross-sectional view, respectively, showing the fifth embodiment, FIGS. 6 and 7 are a perspective view and a sectional view, respectively, showing the sixth embodiment. FIG. 8 is a diagram showing the surface temperature distribution of the piezoelectric laminate shown in the first embodiment and the sixth embodiment as A and B, respectively, and FIGS. They are a partial cross-sectional view and a vertical cross-sectional view, respectively, showing an example. ■... Piezoelectric plate (piezoelectric laminate body), 2... Lead wire, 3... Insulating layer, 4... Heat shrink tube, 5, 5a... Adhesive, 6... Heat conduction Thin metal plate with good properties, 6a... Thin plate tube.

Claims (1)

[Claims] 1. An insulating layer containing at least one of epoxy resin, silicone rubber, heat-shrinkable tube, and adhesive on the outer peripheral side of a piezoelectric plate made of a piezoelectric material and expanded or contracted by applying a voltage. A piezoelectric laminate characterized by being formed by closely forming.