JP2799912B2 - Damping complex - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration damping composite which mainly suppresses vibrations generated from a vibrating body, and more particularly, to a polymer resin sheet containing piezoelectric ceramic powder, in which all or a part thereof is made of carbon. The present invention relates to a vibration damping composite provided with a woven fabric layer composed of fibers.

[0002]

2. Description of the Related Art Conventionally, in a vibration damping complex which converts vibration energy generated by a vibrating body into electric energy, and further converts the vibration energy into heat energy to consume the energy, the vibration energy is increased. In some cases, a piezoelectric body as a medium for converting electric energy into electric energy and an external resistor as a medium for converting electric energy into heat energy are connected.

However, in this case, the external resistor must be connected to the piezoelectric body each time, which is troublesome, and the external resistor connected to the piezoelectric body is protruded from the piezoelectric body. In many cases, there is a drawback that the application to the vibrating body is restricted due to the protrusion, which hinders the attachment to the vibrating body.

In such a situation, there has been proposed a piezoelectric material in which carbon powder or the like is mixed without using the external resistor (described in Japanese Patent Publication No. 61-46498).

[0005]

However, in the case of the prior art in which carbon powder or the like is mixed in the above-mentioned piezoelectric body, the above-mentioned drawback caused by providing an external resistor is eliminated, but the carbon powder and the like are eliminated. It is difficult to mix uniformly in the piezoelectric body, and therefore, the resistance value of each manufactured vibration damping composite tends to vary, and it is difficult to obtain a stable vibration damping effect.

Further, the conventional vibration damping composite in which carbon powder and the like are mixed in the above-described piezoelectric material exhibits an effective vibration damping effect even when the carbon powder and the like are uniformly mixed in the piezoelectric material. When the temperature range is narrow, and especially when the temperature condition is around 50 ° C., the vibration damping effect is sharply reduced. However, there is a serious drawback that a good damping effect cannot be obtained.

[0007] Although the detailed reason why the vibration damping effect is sharply reduced when the temperature condition is around 50 ° C is not clear, one of the possible reasons is that a polymer resin or the like forming a piezoelectric body is used. And, since the coefficient of thermal expansion is different from carbon powder, etc., by increasing the temperature,
The difference between the widths of the carbon powders significantly appears,
For this reason, a portion where the conductive path is broken occurs, and the resistance value is easily changed greatly. Therefore, the conversion from electric energy to heat energy is not sufficiently performed.

The present invention has been devised in view of the above circumstances. The object of the present invention is to have a vibration damping effect over a wide temperature range and maintain an excellent vibration damping effect even in a high temperature range. It is still another object of the present invention to provide a vibration damping composite in which the resistance value of each manufactured vibration damping composite is almost constant and a stable vibration damping effect can be obtained.

[0009]

Means taken by the present invention to achieve the above object will be described below with reference numerals used in the drawings corresponding to the embodiments.

That is, as shown in FIG. 1, FIG. 2 or FIG. 3, the structure of the vibration damping composite according to the first aspect of the present invention is as follows. Or a woven fabric layer 10 partly made of carbon fiber is provided.
"0" as the content.

Next, as shown in FIG. 1, FIG. 2 or FIG. 3, the structure of the vibration damping composite according to the second aspect is as follows.
The vibration damping composite 100 according to claim 1, wherein the epoxy resin is a flexible epoxy resin.

The structure of the vibration damping composite according to claim 3 is as shown in FIG. 1, FIG. 2 or FIG.
The vibration damping composite 100 according to claim 1 or 2, characterized in that a part thereof is made of glass fiber 11.

[0013]

According to the above means, when the vibration energy is applied from an external vibrator, the polymer resin sheet 20 containing the piezoelectric ceramic powder makes the vibration damping composite 100 according to the first aspect of the present invention. This vibration energy is converted to electric energy. The electric energy is converted into thermal energy by the woven fabric layer 10 entirely or partially composed of carbon fibers.

The whole or a part of the woven fabric layer 10 is made of carbon fiber, and is always uniformly arranged as a continuous body. This serves as a conductive path and acts as a resistor, and the electric energy conducted through the resistor is consumed as heat energy. The vibrating body is damped by these actions. This damping action is, as shown in FIG.
It appears remarkably over a temperature range of about 30 ° C. to 90 ° C., and hardly changes particularly in a temperature range of about 40 ° C. to 80 ° C.

Although the detailed reason why there is almost no change in the vibration damping action in the high temperature range of about 40 ° C. to 80 ° C. is not clear, one of the possible reasons is that the woven fabric layer 10 is formed. The carbon fibers are excellent in heat resistance, and are always uniformly arranged as a continuous body in the polymer resin sheet 20, and this forms a conductive path.

The resistance value of the vibration damping composite 100 can be changed by changing the thickness of the carbon fiber and the density of the woven fabric layer 10 or by changing the woven fabric layer 10 by using carbon fiber and other heat-resistant fibers. It can be adjusted by configuring.

Next, in the vibration damping composite according to the second aspect, since the polymer resin sheet 20 has flexibility, in addition to the action of the vibration damping composite according to the first aspect, the composite is broken by an external force. Nothing. Since the vibration damping composite 100 is made of epoxy resin, it has excellent heat resistance.
Is not melted by heat.

The vibration damping complex 100 according to claim 3
As for the woven fabric layer 10, the woven fabric layer 10 is composed of carbon fibers and glass fibers, and the glass fibers 11 have insulating properties. Therefore, the resistance value of the woven fabric layer 10 can be adjusted by increasing it. Since the glass fiber has good heat resistance, it contributes to the development of an excellent vibration damping effect of the vibration damping composite 100 in a high temperature range.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be described below in detail with reference to the drawings, but they show typical ones, and the present invention is not limited by the embodiments.
First, as shown in FIG. 1, FIG. 2 or FIG. 3, the vibration damping composite 100 according to the present embodiment includes an epoxy resin (Epicoat 807 of Yuka Shell Epoxy Co., Ltd.) and a curing agent (Erasuma of Ihara Chemical Co., Ltd.) 1000) in a flexible polymer resin sheet 20 having a woven fabric 10a as a main component.
A woven fabric layer 10 is provided. The polymer resin sheet 20 includes lead zirconate titanate (PZT).
It contains piezoelectric ceramics made of powder.

In the above embodiment, first, the woven fabric 10a
Although the entirety of the warp and the weft is made of carbon fiber, as shown in FIG. 4, a woven fabric 10b woven by putting every other glass fiber in the warp or the weft may be adopted. Further, the glass fibers 11 of the woven fabric 10b may be contained in both the warp and the weft, or may be other than every other. Further, the woven fabric 10b may employ aramid fiber instead of the glass fiber 11. In this case, since the aramid fiber does not soften and melt by heating and withstands a high temperature of about 350 ° C. and has a strength about five times that of iron, the vibration damping layer constituted by the woven cloth layer 10b is used. The composite 100 has excellent heat resistance and high tensile strength. Then, the woven fabric 10b is woven by adding metal fibers or other inorganic fibers, or the thickness of the carbon fiber or the woven fabric 10b.
The resistance value of the vibration damping composite 100 can be adjusted by configuring the woven fabric 10b having the changed density b as the woven fabric layer 10. This woven fabric layer 10 is made of one woven fabric 10a.
Alternatively, it may be constituted by 10b, or may be constituted by overlapping a plurality of them.

Next, in addition to the above epoxy resin, the polymer resin sheet 20 is made of a thermosetting resin such as a phenolic resin, a thermoplastic resin such as polypropylene, polyester, polystyrene, polyvinyl chloride, or the like, or a synthetic rubber, natural rubber, or the like. It may be formed of rubber or the like. Further, as the polymer resin sheet 20, a so-called engineering plastic (including a super engineering plastic) formed of polycarbonate, polyacetal, polyamide or the like may be adopted. Further, in order to impart piezoelectricity to the polymer resin sheet 20 itself, it may be formed of a fluororesin or the like.

Next, the piezoelectric ceramic powder is
Other than ZT, barium titanate (BT), lead zirconate titanate lanthanate (PLZT), etc. may be adopted.
Further, a combination of these may be used.

In the vibration damping composite according to the present invention, a plurality of the vibration damping composites may be used, and the vibration damping effect can be further enhanced.

Here, a method of manufacturing the vibration damping composite 100 according to the present invention will be described below. First, as one manufacturing method, a PZT powder is mixed and stirred in a mixed liquid mainly containing an epoxy resin and a curing agent. The viscosity at this time is 1
It is about 20,000 to 20,000 CPS. Next, this mixed solution is applied to both surfaces of the woven fabric 10a by a roll coating method, a knife coating method, or the like. Next, a heated press plate of a hot press machine is brought into contact with the applied surface to form and solidify, thereby manufacturing the vibration damping composite 100. The surface temperature of the press plate at this time is about 180 ° C to 200 ° C.

As another manufacturing method, first, PZT powder is mixed and stirred in a liquid mixture containing an epoxy resin and a curing agent as main components. Next, the mixed liquid is injected into a molding die in which the woven fabric 10a is previously arranged, and bubbles generated in the injected polymer resin liquid are removed. Then, it is heated and solidified in a hot air dryer. At this time, the atmosphere temperature in the hot air dryer is about 180 ° C to 200 ° C.

With respect to the vibration damping composite according to the present invention thus obtained, the following measurement was performed to evaluate the vibration damping effect, and the graph shown in FIG. 5 was obtained.

In this measurement, for comparison, a conventional vibration damping composite obtained by heating and molding a mixture of carbon powder mixed in an epoxy resin liquid containing PZT powder was also performed. However, the graph shown in FIG. 6 was obtained.

At this time, as shown in FIG.
Electromagnetic Excitation Detector (MT-1, A
202) The sample of the embodiment and the conventional example which are measured using 136 mm × 15 mm × 1 mm, and a 1 mm-thick iron plate is adhered to one side of the sample by adhesion or the like, and the measurement is performed. did.

The loss coefficient η in the figure is η = 2D /
It was determined from 8.68 × 2 × 3.14 × f ₀ . Here, D in the equation is the degree of attenuation (indicating how many dB per second).
And f ₀ is the resonance frequency.

As is clear from the graph shown in FIG. 5, the vibration damping composite according to the present embodiment has a temperature of 40.degree.
It can be seen that a substantially constant loss coefficient is obtained over a wide range of 0 ° C. and over a high temperature range, and the vibration damping effect is excellent.
Further, with respect to the vibration damping complex according to the present example, even when the measurement was performed while changing the sample (N = 3), the result showed a substantially constant value, and could be plotted almost at a position on the graph. . That is, the vibration damping effect of the vibration damping complex according to this embodiment is stable.

In contrast, as is clear from FIG.
For the vibration damping composite according to the conventional example in which carbon powder was kneaded in a resin, the loss coefficient sharply decreased from around 50 ° C., the temperature region showing a good vibration damping effect was narrow, and the temperature was 50 ° C. or higher. It can be seen that the vibration control effect in the region is inferior.
Further, with respect to the vibration damping complex according to the conventional example, a large difference occurs in the measured value every time the sample (N = 3) is changed, and there is a large variation in the plotted position on the graph. That is, the damping effect of the damping complex according to the conventional example is unstable.

As described above, the vibration damping complex according to the present invention
Excellent vibration damping effect even in high temperature range, and furthermore, vibration of the vibrating body can be suppressed only by sticking to the vibrating body without using an external resistor. This is particularly effective when damping a device that tends to have a relatively high temperature, such as near an acoustic device or an engine of an automobile.

[0033]

As described above, when the vibration damping composite according to the present invention is employed, the following effects can be obtained.

First, in the vibration damping composite according to the first aspect, a woven fabric layer entirely or partially composed of carbon fibers is provided as a resistor in the polymer resin sheet. It has a damping effect over a wide temperature range and maintains a high damping effect even in a high temperature range. Furthermore, since the woven fabric layer is always disposed in a uniform state in the vibration damping composite, its resistance value is lower than that of the conventional one using carbon powder or the like, which is difficult to mix uniformly. It is constant. Therefore, a stable vibration damping effect can be obtained.

Next, in the vibration damping composite according to the second aspect, since the polymer resin sheet is made of a flexible epoxy resin, in addition to the effects of the first aspect,
The vibration damping complex itself does not break due to external force, and is resistant to impacts. In addition, since the composite material is excellent in heat resistance, even when this vibration damping composite is used by attaching it to a high-temperature vibrator, the polymer resin sheet is safe without melting.

In the vibration damping composite according to the third aspect, the woven fabric layer is composed of carbon fibers and glass fibers, and the glass fibers have insulating properties. The resistance value can be adjusted.
Moreover, since the glass fiber has good heat resistance, it contributes to the development of a high vibration damping effect in a high temperature range (around 50 ° C. to 80 ° C.) of the vibration damping composite. In addition, glass fibers are less expensive than carbon fibers, and are therefore cost effective to use.

[Brief description of the drawings]

FIG. 1 is a perspective view of a vibration damping composite according to the present invention.

FIG. 2 is a partial sectional view of FIG.

FIG. 3 is a perspective view of the woven fabric in FIG. 1;

FIG. 4 is a perspective view of a woven fabric according to another embodiment different from FIG.

FIG. 5 is a graph showing a loss coefficient and the like of the vibration damping composite according to the present example.

FIG. 6 is a graph showing a loss coefficient and the like of a vibration damping composite according to a conventional example.

FIG. 7 is a front view of the electromagnetic excitation detection device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Woven fabric layer 11 Glass fiber 20 Polymer resin sheet 100 Vibration suppression composite according to the present invention

Claims (3)

(57) [Claims] 1. A vibration damping composite, characterized in that a polymer resin sheet containing piezoelectric ceramic powder is provided with a woven fabric layer entirely or partially composed of carbon fibers. 2. The vibration damping composite according to claim 1, wherein the polymer resin is a flexible epoxy resin. 3. The vibration damping composite according to claim 1, wherein a part of the woven fabric layer is made of glass fiber.