JPS62230071A - Coaxial mechanical-electrical transducer - Google Patents

Abstract

PURPOSE:To eliminate an air layer in a coaxial mechanical/electrical converter and to reduce the outer diameter of the converter by covering the outer periphery of the surface of a piezoelectric layer with a thermally shrinkable tube. CONSTITUTION:A conductive rubber core electrode layer 4 having a core electrode 3 made of a linear conductive material is buried at the center of a piezoelectric layer 2 made of a piezoelectric rubber. The outer periphery is sequentially covered with a sheath electrode layer 5 and a thermally shrinkable tube 5. In order to form the layer 5 and the tube 6, the layer 2 is coated with conductive patent such as silver rubber paint to form the layer 5, hot blast is blown to a synthetic resin tube 7 having an inner diameter slightly larger thermal shrinkage than the outer diameter of the layer 2 through the layer 2 to heat it to shrink the tube 7 as the tube 6. Thus, the outer diameter becomes substantially half, and no air layer is generated therein to generate a preferable signal voltage.

Description

[Detailed Description of the Invention] <Field of Application in Industry> The present invention provides a method in which a core electrode is embedded in the center of a piezoelectric layer made of a flexible piezoelectric material, and the surface of the piezoelectric layer is covered with an outer covering electrode. Regarding the coaxial electromechanical transducer.

+1) The flexible piezoelectric material converts mechanical stress into a potential difference between the core electrode and the outer electrode, or converts electrical vibration into mechanical vibration.

<Conventional branch technique> FTf flexible positive piezoelectric material applied to this type of coaxial electromechanical transducer element Mix ferroelectric ceramic particles of lead zirconate titanate and lead titanate caps in synthetic rubber or synthetic resin It is an ultrasonic transducer because its nT)4 property allows it to be easily displaced in response to mechanical stress and provides a good output voltage.

Used in a variety of applications, including underwater microphones, vibration detection sensors for internal combustion engines, and string vibration pickup caps for electric pianos.

This conventional coaxial mechanical electrical transformation! ! ! ! As shown in Fig. 4, the general structure of the I element is that a core electrode is buried in the center of a piezoelectric layer a made of a flexible piezoelectric material, and the surface of the pressure layer a is covered with an aluminum layer that serves as an outer covering electrode. It is covered with foil C, which is further molded with conductive braid d, and then covered with the outer skin He of the urethane rubber cap.

By the way, in such a configuration, an air layer is formed between the aluminum foil C and the conductive braid d, which impairs the characteristics as a sensor, and the conductive braid! [There was a drawback that noise was generated due to sliding on the aluminum foil C as Id expanded and contracted.

Furthermore, since the thickness of the outer skin layer e is about 0.9 square centimeters, the outer diameter of the element becomes large, about 2.9 mm, which limits its use.

The object of the present invention is to provide a coaxial electromechanical transducer r. without the above-mentioned drawbacks.

Means for Solving the Problems> The present invention provides a mechanical electrical system in which a core 'llf electrode is embedded in the center of a piezoelectric layer made of a flexible piezoelectric material, and the surface of the piezoelectric layer is covered with a covering electrode. 4! The outer peripheral surface of the conversion element was covered with a heat shrink tube! I@.

Effects> In case 1, the piezoelectric layer is covered with a heat-shrinkable tube, so the tube is in close contact with the piezoelectric layer, and no air space is created, and the outer diameter of the tube can be made as small as possible. .

<Example> Figure 1.2 shows a coaxial electromechanical transducer J' according to the present invention.
An example of No. 1 is shown below.

Here, 2 is a piezoelectric layer made of piezoelectric rubber, and a core electrode layer 4 made of conductive rubber having a core electrode 3 made of a linear conductive material is embedded in the center thereof.

Also, on its outer periphery, there is an outer skin 1, a hypopolar layer 5, and a heat shrink tube 6.
are applied in sequence.

The heat shrink tube 6 also covers one end of the piezoelectric layer 2,
Furthermore, from the other end, a core electrode 3. The outer skin electrode layer 5 is exposed and connected to the lead wire 10.10, and the core electrode layer 3. The potential difference between the outer skin electrode layers 5 is extracted as an electric signal through the lead wires 10 and 10.

The outer electrode layer5. The means for forming the heat-shrinkable tube 6 is as shown in FIG.
As shown in the figure, the piezoelectric layer 2 is passed through a heat-shrinkable synthetic resin tube 7 whose inner diameter is slightly larger than the outer diameter of the piezoelectric layer 2, and heated by means such as blowing hot air onto the synthetic resin tube 7. Then, as shown in FIG. 3, the synthetic resin tube 7
This can be done by shrinking it to form a heat-shrinkable tube 6.

The outer electrode layer 5 is formed on the outer periphery of the piezoelectric layer 2 by applying a conductive paint to the inner peripheral surface of the synthetic resin tube 7 in advance and shrinking the synthetic resin tube 7. You may also do so.

Furthermore, by forming the synthetic resin tube 7 from a conductive material, the outer electrode layer 5 and the heat shrinkable tube 6 are
It may also be used for both.

In this configuration, the thickness of the heat shrink tube 6 is 0.
．． 151111, and the outer diameter of the piezoelectric layer 2 is φ1゜2.
In this case, the outer diameter of one mechanical-electrical transducer 1 is approximately φ1.5, which is approximately half that of the conventional one.

Further, in the above configuration, the material of the heat shrinkable tube 6 can be selected from various materials depending on the intended use, taking into account properties such as chemical resistance, abrasion resistance, and pressure resistance. That is, by selecting the heat shrink tube 6, the mechanical and electrical conversion elements 1
will acquire characteristics that correspond to its use.

<Effects of the Invention> The present invention has the following advantages: 1: As described above, the piezoelectric layer 2 is protected by being covered with the heat shrink tube 6, so no air layer is formed inside the piezoelectric layer 2, and a good In addition to being able to generate a signal voltage, the outside diameter is as small as possible, and furthermore, the structure is simple, so the shade has the excellent effect of being easy to manufacture and requiring low power consumption.

[Brief explanation of drawings]

The accompanying drawings show embodiments of the present invention; FIG. 1 is a longitudinal side view of the electromechanical transducer 1, FIG. 2 is a cross-sectional side view thereof, and FIGS. 3A to 3C are cross-sectional side views showing the manufacturing process. 4 are cross-sectional side views of the conventional configuration. 1; Mechanical-electric conversion element 2; Piezoelectric layer 3: Core electrode 35;
Outer electrode layer 6; Heat shrink tube・Ij 1m, &
[1, t 4'fi # :ia * 671
,・Pa1,1 Agent Patent Attorney': Matsu in Kita Man 3.111. ;、=. Figure 4

Claims (1)

[Claims] 1) In a mechano-electrical transducer in which a core electrode is buried in the center of a piezoelectric layer made of a flexible piezoelectric material and the surface of the piezoelectric layer is covered with an outer covering electrode, the outer peripheral surface thereof is A coaxial electromechanical transducer characterized by being covered with a heat-shrinkable tube. 2) The surface of the piezoelectric layer is coated with a conductive paint such as a silver-based rubber paint to form a sheathed electrode, and the outer peripheral surface of the sheathed electrode is further covered with a heat-shrinkable tube. The coaxial electromechanical transducer described in Section 1. 3) Claim 1) characterized in that a heat-shrinkable tube whose inner surface is coated with a conductive paint such as a silver-based rubber paint to form a sheathed electrode is adhered to the outer peripheral surface of the piezoelectric layer. The coaxial electromechanical transducer described above. 4) A coaxial electromechanical transducer according to claim 1, characterized in that the heat-shrinkable tube is conductive and serves also as a jacket electrode.