JP2508263B2 - Electrostrictive effect element and manufacturing method thereof - Google Patents

Description

The present invention relates to an electrostrictive effect element utilizing the electrostrictive longitudinal effect and a method for manufacturing the same.

[Conventional technology]

Conventionally, as a packaging method of this type of electrostrictive effect element, a method of dip molding or cast molding of a liquid resin, a method of molding a semi-solid resin, a powdered resin is adhered and cured by an electrostatic coating method or a fluid immersion method. There was a method of molding.
That is, conventionally, only the resin is used for packaging, and as measures for improving moisture resistance, the packaging thickness can be increased, multiple layers of resins with different properties can be formed, inorganic fillers can be mixed in the resin material, or low impurity concentration can be used. It was packaged using the resin material of.

[Problems to be Solved by the Invention]

The conventional electrostrictive effect element packaging method described above cannot prevent the permeation of moisture as long as a resin is used, and any method from the viewpoint of maintaining moisture resistance in the resin coating does not have a great effect. could not.

In addition, the impurities mixed in the resin deteriorated the moisture resistance, the gap between the electrostrictive effect element interface due to shrinkage during curing, and the electrostrictive effect decreased due to internal stress.

An object of the present invention is to solve these problems and to completely seal the inside of a case accommodating an element, thereby improving the moisture resistance, protecting the element, and improving the reliability, and an electrostrictive effect element and a manufacturing method thereof. To provide.

[Means for solving the problem]

The configuration of the electrostrictive effect element of the present invention is a plurality of sheets in which plate-shaped electrostrictive ceramic members and internal electrode conductors are alternately laminated and integrally fired, or a single plate of fired ceramic members is formed with internal electrode conductors. A laminated sintered body provided with an external electrode conductor in a united body by adhesion, a heat-shrinkable tube covering the side surface of the laminated sintered body and shrinking by heating, and a laminated sintered body covered with the heat-shrinkable tube A metal case that surrounds the side surface of the laminated sintered body and is flexible in the polarization direction of the laminated sintered body; a metal stem that is joined to the metallic case and is joined to the upper and lower surfaces of the metallic case to seal the inside of the case; An external terminal electrically adhered to the external electrode conductor of the sintered body through a lead wire and hermetically sealed to the metal stem, and inserted into a hole penetrating a part of the metal stem. Metal rivets And having a preparative.

The structure of the manufacturing method of the electrostrictive effect element of the present invention is such that after electrically connecting the external electrode conductor of the laminated sintered body of the terminal of the metal stem via the lead wire, metal is applied to both ends of the laminated sintered body. A step of fixing the bottom inner side of the case and one surface of the metal stem via an adhesive, respectively, a step of welding the contact portion between the metal case and the metal stem, and vacuuming the metal case and the metal stem. After heat treatment, a step of replacing the inside of the metal case with dry air or dry inert gas through the hole of the metal stem, and then fitting a metal rivet to the rear part of the metal stem and sealing with solder or brazing material And a step of performing.

〔Example〕

 Next, the present invention will be described with reference to the drawings.

FIGS. 1 (a), (b), and (c) show a longitudinal sectional view of an electrostrictive effect element before packaging according to a first embodiment of the present invention, a longitudinal sectional view after packaging, and an external perspective view thereof. FIG. 2 is a flow chart showing the assembling steps of this embodiment in the order of steps.

 This embodiment will be described in the order of manufacturing steps.

First, in FIG. 1 (a), lead niobate nickelate is used.
Pb (Ni _1/3 N _2/3 ) O ₃ , lead titanate PbTiO _{3 and} other pre-calcined powders of electrostrictive materials in an organic binder such as polybutyl vinylal and an organic solvent such as ethyl cellosolve. Approximately 150 μm of the mixture dispersed in
A thick electrostrictive ceramic member 1 is formed. Next, a conductor paste consisting of a silver / palladium mixed powder having a weight ratio of 70:30 and an organic vehicle was applied to one surface of the electrostrictive ceramic member 1 by screen printing to a thickness of about 10 μm, and the internal electrode conductor 2 was formed.
To form.

After laminating a plurality of these to make a laminate, 1100 ℃ 2
After sintering under conditions of time holding, by cutting the side face, the ends of the internal electrodes 2 ₁ to 2 _n-1 to produce a prismatic laminated sintered body 3 exposed to the outside (of FIG. 2 Step 101).

Then, the end portion of the inner electrode conductor 2 ₁ ~2 _n-1 exposed to the pair of opposing side surfaces of the laminated sintered body 3 is subjected to deposition and baking glass powder alternately in the side surface by electrophoresis , an insulating layer 4 ₁ ~4 _n-1. And to be electrically connected to every other layer of these inner electrode conductor 2 ₁ ~2 _n-1, by baking by applying a conductive paste dispersed in an organic vehicle of silver powder by screen printing, a pair of external The electrode conductors 5a and 5b are formed and the lead wires 6a and 6b electrically connected thereto are connected (step 102).

As shown in FIG. 1 (b), the laminated sintered body 3 is covered with a heat-shrinkable tube 7 made of silicone rubber, PTFE or the like and shrinkable by heating, and heated to a shrinkage temperature to be in close contact (step 103).

Next, the disk-shaped stem 8 made of stainless steel, beryllium, copper, aluminum or the like is attached to the hermetic seals 15a and 15b.
Solder a pair of external terminals 9a, 9b made of copper, iron, nickel or an alloy of these and lead wires 6a, 6b,
Alternatively, they are electrically connected by welding or the like (step 104).

Next, a metal stem 8 surrounding the upper and lower surfaces of the laminated sintered body 3 and a metal material equivalent to the metal stem 8 are drawn into a cylindrical shape with one side closed, and further pressed into the cylinder by hydraulic pressing or the like. The uneven metal part 11a is provided in a part of the metal case 11 and the bottom of the metal case 11 having flexibility is brought into contact with the adhesive 12 such as epoxy through an adhesive 12 (step 104).

Next, the contact portion 11b between the metal stem 8 and the metal case 11 is welded and sealed by laser beam, electron beam or TIG welding (step 105).

Next, this is vacuum-heated at 150 ° C. for 1 hour at 10 Pa (step 106), and moisture and gas remaining in the metal case 11 are released through the hole 8a provided in the metal stem 8.
After injecting an inert gas such as dry air or N ₂ gas Ar gas with a dew point of about -30 ° C at a constant temperature to atmospheric pressure (Step 10
7), insert a metal rivet 13 made of a copper alloy, an aluminum alloy or the like into the chip or screw it (step 10
8) Then, sealing is performed by soldering or brazing from above (step 109).

3 (a) and 3 (b) are a structural perspective view and a longitudinal sectional view thereof, respectively, of the electrostrictive effect element according to the second embodiment of the present invention before being packaged. This electrostrictive effect element is usually called a stack type, and the internal electrode conductors 20 _{1 to} 20 _n-1 are formed on one surface of a pre-fired disc-shaped electrostrictive ceramic member 10 leaving margins 20a and 20b. Then, as shown in FIG. 3 (a), the blank portions 20a and 20b where the internal electrode conductors 20 are not exposed are alternately arranged at both ends of the side surface,
Each electrostrictive ceramic member 10 ₁ a to 10 _n adhesive, or bonded with a glass frit or the like to form a cylindrical laminate 30.
Next, a pair of external electrode conductors 5 whose width is smaller than the margins 20a and 20b
a and 5b are formed, and the inner electrode conductors are alternately arranged in alternate layers.
Electrically connect the exposed parts of 20 _{1 to} 20 _n-1 . Furthermore, after providing the lead wires 6a and 6b electrically connected to the external electrode conductors 5a and 5b, the side surfaces are covered with the heat shrinkable tube 7.

In this way, the stack type laminated electrostrictive effect element is obtained, and is completed by completely sealing it with the metal case 11 and the metal stem 8 as in the first embodiment.

The electrostrictive effect element of these examples, when voltage is applied to the external terminals 9a, 9b, the electrostrictive ceramics via the lead wires 6a, 6b, the external electrode conductors 5a, 5b and the internal electrode conductors 2 ₁ to 2 _n-1. Member 1
Alternatively, when an electric field is applied in the thickness direction of 10 and the metal stem 8 is fixed, the arrow A shown in FIG.
Generates a displacement and a force in the direction of.

FIG. 4 shows that a DC rated voltage was applied to the device of this example,
It is a graph which showed the result of the humidity resistance test in 60 ° C 90-95%. In this case, the number of samples was 200 for each of the conventional product with the resin-only exterior and the example. The device according to the present example has almost no defects even after 1000 hours.

〔The invention's effect〕

As described above, according to the present invention, the side surface of the electrostrictive effect element is covered with the heat-shrinkable tube, surrounded by the metal case and the metal stem, and completely sealed by welding. Since it is protected from scratches and internal stress due to the resin does not occur, there is an effect that the reliability of the electrostrictive effect element can be improved.

In particular, the laminated electrostrictive effect element is protected by a heat-shrinkable tube to protect it from scratches, dust, and contamination during the assembly process. , The influence of impurities and the internal stress of shrinkage are remarkably relieved. Further, by completely sealing the metal case and the metal stem, there is an effect that the environment can be protected from the external environment.

[Brief description of drawings]

FIGS. 1 (a), (b) and (c) are a longitudinal sectional view of an electrostrictive effect element according to a first embodiment of the present invention, a longitudinal sectional view of the electrostrictive effect element after its exterior and an external perspective view, and FIG. 1 is a flow chart showing the embodiment of FIG. 1 in the order of manufacturing steps, and FIGS. 3 (a) and 3 (b) show the second embodiment of the present invention.
FIG. 4 is an exploded perspective view of the electrostrictive effect element of Example 1 and a longitudinal sectional view thereof, and FIG. 4 is a graph showing the results of humidity resistance tests of the elements of the present invention and the conventional example. 1 ₁ to 1 _n , 10 ₁ to 10 _n ... Electrostrictive ceramic member, 2 ₁ to 2 _n-1 , 20
_{1 to} 20 _n-1 … Internal electrode conductor, 3,30… Layered sintered body, 4 ₁ to 4 _n-1
... Insulating layer, 5a, 5b ... External electrode conductor, 6a, 6b ... Lead wire, 7
… Heat shrink tube, 8… Metal stem, 8a… Hole, 9a, 9b
... external terminals, 11 ... metal case, 11a ... uneven parts, 11b ... contact parts, 12 ... adhesive material, 13 ... rivets, 15a, 15b ... hermetic seal parts, 101-109 ... treatment steps.

Claims (2)

(57) [Claims] 1. A plate-shaped electrostrictive ceramic member and internal electrode conductors are alternately laminated and integrally fired, or a plurality of fired ceramic member single plates on which internal electrode conductors are formed are bonded and integrated. A laminated sintered body provided with an external electrode conductor, a heat-shrinkable tube that covers the side surface of the laminated sintered body and shrinks by heating, and surrounds the side surface of the laminated sintered body covered with the heat-shrinkable tube and A metal case having flexibility in the polarization direction of the laminated sintered body, a metal stem that is joined to the metal case and is joined to the upper and lower surfaces of the metal case to seal the inside of the case, and an external electrode of the laminated sintered body. An external terminal electrically connected to a conductor through a lead wire and hermetically sealed to the metal stem; and a metal rivet fitted into a hole penetrating a part of the metal stem and inserted. Electrostrictive effect element characterized. 2. A terminal of a metal stem is electrically connected to an external electrode conductor of a laminated sintered body through a lead wire, and both ends of the laminated sintered body are connected to the inside of the bottom of the metal case and the metal stem. A step of fixing one side to each side with an adhesive,
Welding the metal case and the contact portion between the metal stem and the metal case, after vacuum heating the metal case and the metal stem, dry air or dry inert gas inside the metal case through the hole of the metal stem. A method of manufacturing an electrostrictive effect element, comprising: a step of substituting with a gas; and a step of subsequently fitting a metal rivet to a rear portion of the metal stem and sealing with a solder and a brazing material.