JPS62183335A - Laminated metallic plate having excellent vibration-damping property - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a sandwich structure having both good specific stiffness and vibration damping properties.

BACKGROUND OF THE INVENTION In recent years, noise caused by automobiles has become a social problem. In addition, from the viewpoint of comfort inside the vehicle, there is a need for noise countermeasures, especially in diesel vehicles. In particular, as a measure to reduce vibrations around engines, vibration-damping steel plates, which are sandwiched between two steel plates using a viscoelastic resin as a damping material, are beginning to attract attention (Plasticity and Processing, Vol. 26, No. 291, 384-389).

However, the damping steel plate is constructed by sandwiching a thin soft viscoelastic resin of about 0.05 m between thick steel plates of about 0.4 to 0.81 m, and when the damping steel plate vibrates, the resin layer shears (slips). ) Absorbs energy by causing plastic deformation and exhibits vibration damping properties. Conversely, since shear deformation occurs between the skin steel plates with a small amount of force, the bending rigidity thereof is significantly lower than that of a cold-rolled steel plate having the same overall thickness.

Therefore, in order to ensure the same rigidity as a cold-rolled steel plate with a damping steel plate, the total thickness must be increased, that is, the amount of steel plate used must be increased, resulting in an increase in weight.

If damping steel plates are used as structural members, they are heavy themselves, and at the same time the rigidity of the members supporting them must also be improved, which increases the weight of the entire structure. In addition, the increase in the amount of steel used leads to an increase in costs and increases in fuel consumption in automobiles, etc., which is not necessarily an advantageous direction in a social situation where energy conservation and cost conservation are emphasized.

In this sense, there is a real need for materials that are lightweight and have high vibration damping performance, and are also in high demand in fields other than automobiles, such as home appliances, furniture, and building materials that require the reduction of chatter and impact noise. .

Problems to be Solved by the Invention The present invention provides a laminated metal plate that is lightweight and has excellent vibration damping properties in response to the above social demands.

A laminated metal plate is a laminate of steel plate-resin-steel plate in which an elastic resin (core material) such as nylon-6 or polypropylene is sandwiched between two metal plates (skin metal plate).The skin and core material resist external forces. They deform as one, and there is no shear deformation between the skin and the core material unlike with damping steel plates.Therefore, the bending rigidity is almost the same as that of the metal plate when the total thickness is the same, and the center Since the specific gravity of the resin layer is about 1/3 to 1/8 of that of the metal plate, it is possible to reduce the weight by several tens of percent. However, in terms of damping properties, the resin layer does not undergo plastic deformation due to shearing, so the mechanism in the damping steel plate does not produce damping properties. This invention relates to a laminated metal plate that provides vibration damping properties to the plate using a new mechanism, making it possible to achieve both vibration damping properties and weight reduction at the same time.

Means for Solving the Problems The gist of the present invention is as follows. That is, (1) in a laminated metal plate formed by sandwiching and fixing a resin layer between metal plates, the joint surface between the metal plate and the resin layer is composed of an elastic resin part and a viscoelastic resin part, and the area ratio is expressed by the following formula. at 25
% or more and 98% or less. A laminated metal plate with excellent vibration damping properties.

(2) In the viscoelastic resin part of (1) above, the viscoelastic resin is interposed between the metal plate and the elastic resin, and its thickness is ma.
A laminated metal plate with excellent vibration damping properties that is smaller than the thickness of the layers.

(3) A laminated metal plate with excellent vibration damping properties, characterized in that the viscoelastic resin portion of (1) above is composed of only the viscoelastic resin without any elastic resin present in the viscoelastic resin portion.

Function The present invention has found that when a viscoelastic resin portion is provided on the joint surface between the skin metal plate and the elastic resin layer, vibration damping properties can be imparted to the laminated metal plate without reducing its specific rigidity. It is something.

That is, according to the experiments of the present inventors, for example, two skin metal plates were made of a 0.2 weight steel plate (spB-rL), and the core material was an adhesive polypropylene sheet made by Ube Industries, and the total thickness was 0.
．． A laminated steel plate was produced by hot pressing to a thickness of 9 mm. In this case, the viscoelastic resin part can be made by cutting out the resin film in advance and inserting the viscoelastic resin into the viscoelastic resin part, or by making a depression in the polypropylene resin film, placing the viscoelastic resin there, and hot-pressing it with the steel plate. A resin part was provided.

If the horizontal axis is the percentage (%) of the total area of the viscoelastic resin part (total area of the viscoelastic resin part, total area of the elastic resin part), and the vertical axis is the loudness of the hitting sound (dB (C)). As shown in FIG. 2, when the area ratio was 25% or more, a significant decrease in the magnitude of the hitting sound, that is, an improvement in vibration damping performance, was observed. Here, the mark O in the figure indicates the case where the viscoelastic resin 9 is thinly present along the bonding surface as shown in FIG. 4 (1) (case of claim 2), and the mark . As shown in FIG. 4 (2), this is a case in which a viscoelastic resin 9 is interposed in the entire thickness direction from one side 7 of the skin metal plate to the other side 7 (case according to claim 3).

In the present invention, vibration damping performance was evaluated by reducing the sound of the object being hit. That is, as shown in FIG. 1, a steel ball 4 is dropped horizontally in a pendulum shape and hit the center of a test panel 3 fixed to a wall 1 with a knife 2, and the generated sound is recorded by a microphone 5.
It was captured by Analyzer 6 and analyzed by Analyzer 6.

In addition, the area ratio and bending stiffness kgsm 2/arm
) As shown in FIG. 3, the symbols in FIG. 0, which showed good rigidity at 38% or less, are the same as in FIG. 2.

The bending stiffness was measured in accordance with ASTM D-790 using a specimen having a five-shaft structure, a length of 150 mm, and a bending span of 100 layers.

As explained above, the sound reduction (approximately 2 dB) that can be felt by the auditory senses is
C) In order to achieve ), there must be at least 25% viscoelastic resin portion.

Further, the upper limit is an area ratio of 98% as a range in which a decrease in bending rigidity is acceptable.

Also, there are two joining surfaces, upper and lower, between the metal plate and the resin layer.
In the present invention, when a viscoelastic resin layer is interposed between the elastic resin layer and the metal plate, it is sufficient to have the viscoelastic resin layer on at least one joint surface. There is no problem in having an elastic resin layer.

Next, the metal plates used as the skin are not particularly limited, but examples include cold-rolled thin plates, various plated steel plates, organic coated steel plates, chemical conversion treated steel plates, patterned steel plates, mild steel plates, high-strength steel plates, pure aluminum plates, and various other metal plates. Examples include aluminum alloy plates, pure copper plates, copper alloy plates, and stainless steel plates. In addition, a steel plate or striped steel plate with an uneven surface may be used, or two different types of metal plates may be used simultaneously for the two skins, the thickness of which is determined by the use and desired performance. Although not limited to, it is typically about 0.1 to 21.

Examples of resins used as elastic resins include polyolefins such as polypropylene, polyethylene, and poly4-methylpentene-1, which are commonly used in laminated metal plates, polyamides such as vinyl chloride polymers, cellulose polymers, nylon, and polyethylene terephraglate. Examples include polyester, polycarbonate, epoxy resin, acrylic resin, polyurethane, and the above-mentioned modified resins (Japanese Unexamined Patent Publication No. 55-158052, etc.).Furthermore, the thickness of the resin layer is the same as the thickness of the skin metal plate. Although it is determined depending on the use and the desired performance and is not limited, it is typically about 0.05 to 5 layers.

In addition, as a viscoelastic resin, it is required to be viscoelastic.
Examples of the resins used include modified polyolefins, acrylic acid polymers, and vinyl acetate polymers represented by EVA.

Laminated metal plates can be manufactured using the usual hot press method, a continuous line method in which heat fusion is performed continuously, or a method in which the core material and the metal plate are bonded with adhesive (batch or continuous methods are possible). .

When vibration occurs, the skin metal plate vibrates in this viscoelastic resin part, the vibration vibrates the viscoelastic resin, and the viscoelastic resin layer converts the vibrational energy into thermal energy, exhibiting vibration damping properties. It seems that it will. Therefore, this is different from conventional damping steel plates that utilize macroscopic shear deformation of viscoelastic resin.

Next, although the size and shape of the viscoelastic resin part are not particularly limited, it is necessary that the viscoelastic resin part and the elastic resin part are arranged alternately. That is, it is necessary that the viscoelastic resin parts are randomly arranged within the elastic resin part (or the elastic resin parts are arranged within the viscoelastic resin part).

Examples of the arrangement are illustrated in FIGS. 5-8. The shaded area indicates the viscoelastic resin part, and the blank space indicates the elastic resin part.

Example Table 1 shows examples (standards) for comparison.

The weight reduction rate is the percentage of the metal plate used as the skin material alone when the bending rigidity is the same. Comparative Example 1 is a normal laminated steel plate. Comparative Example 2 is a cold rolled steel plate. Both have poor vibration damping properties.

Table 2 shows examples in which a viscoelastic resin layer is provided between the metal plate and the resin layer of the viscoelastic resin part. There are three shapes of the viscoelastic resin part or the elastic resin part: square, circular, and rectangular.

Table 3 shows examples in which there is no elastic resin layer in the viscoelastic resin portion. The shape of the viscoelastic resin part or the elastic resin part is of three types: square, circular, and rectangular.

For the skin (metal plate), steel plates were degreased with 2 ml of weak alkaline degreasing solution, pure aluminum plates were degreased with 10 ml of 3% NaOH aqueous solution, and copper plates were degreased with 10% HNO3 aqueous solution.

A hot press method was used to fix the resin layer and the metal plate. When using polypropylene (PP), the hot pressing conditions are: Raise the temperature to 180℃, maintain 2 layers, and then press at 13℃.
The temperature was cooled to 0°C, and when nylon-6 (NY) was used, the temperature was raised to 220°C, held at 2 inches, and then cooled to 140°C. The pressure of the hot press was always 2 kg/c.

In all of Examples 1 to 10 in Tables 2 and 3, vibration damping properties were improved while reducing weight compared to the comparative example.

As described in detail, according to the present invention, it is possible to reduce the weight of a laminated metal plate, maintain a high specific stiffness (bending stiffness/specific gravity), and provide vibration damping properties.

[Brief explanation of the drawings] Fig. 1 is an elevational view explaining the method of measuring the tapping sound, Fig. 2 is a diagram showing the relationship between the area ratio of the viscoelastic resin and the magnitude of the tapping sound, and Fig. 3 is a diagram of the relationship between the area ratio of the viscoelastic resin and the magnitude of the tapping sound. Figures 4 (1) and (2), which are relationship diagrams between area ratio and bending stiffness (bending stiffness), show cases where an elastic resin layer exists in the viscoelastic resin part and cases where the viscoelastic resin part is composed only of viscoelastic resin, respectively. A cross-sectional view of the laminated metal plate of the present invention in the case where the laminated metal plate of the present invention is used is an explanatory view showing the shape of the viscoelastic resin portion. l... wall, 2... knife, 3... fist test panel, 4... steel ball, 5Φ... microphone, 6... analyzer, 7... skin metal plate, 8... elasticity Resin, 9.
...Viscoelastic resin.

Claims (1)

[Claims] (1) In a laminated metal plate in which a resin layer is sandwiched and fixed between metal plates, the joint surface between the metal plate and the resin layer is composed of an elastic resin part and a viscoelastic resin part, and the following formula is used. A laminated metal plate with excellent vibration damping properties, characterized in that the area ratio shown is within a range of 25% or more and 98% or less. Area ratio (%) = (total area of viscoelastic resin part / total area of viscoelastic resin part + total area of elastic resin part) x 100 (%)
(2) In the viscoelastic resin portion, the viscoelastic resin is interposed between the metal plate and the elastic resin, and the thickness thereof is smaller than the thickness of the resin layer. laminated metal sheet. (3) The laminated metal plate according to claim (1), characterized in that the space between the two skin metal plates is filled only with a viscoelastic resin over the entire thickness direction.