JPS62174144A - 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 good specific stiffness and vibration damping properties at the same time.

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 has a structure in which a thin soft viscoelastic resin of about 0.05 mm is sandwiched between thick steel plates of about 0.4 to 0.8 mm, and when the damping steel plate vibrates,
The resin layer absorbs energy by causing shear (shear) 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.

To imitate this increase in weight, damping steel plates, when used as structural members, are heavy themselves, and at the same time the rigidity of the members supporting them must also be improved, resulting in an increase in the weight of the entire structure, In addition, the increase in the amount of steel used leads to increased costs and increases in fuel efficiency for automobiles.
This is not necessarily an advantageous direction given the social situation where energy and cost savings 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 demand in fields other than automobiles, such as home appliances, furniture, and building materials that require the reduction of chatter and impact noise. is high.

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. It deforms as a unit, and unlike vibration-damping steel plates, there is no shear deformation between the skin and core material. Therefore, the bending rigidity is almost the same as that of the metal plate with the same total thickness, and the specific gravity of the central resin layer is about 1/3 to 1/8 of that of the metal plate, so the weight can be reduced by several tens of percent. It is possible. However, regarding vibration damping properties, the resin layer does not undergo plastic deformation due to shearing, so the mechanism in the vibration damping steel plate described in section 1 does not produce damping properties. One object of the present invention is to provide a laminated metal plate that imparts vibration damping properties to such a laminated metal plate using a novel mechanism, thereby 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. In other words, (1) in a laminated metal plate in which a resin layer is sandwiched and fixed between metal plates, the metal plate and the resin layer = the gap and the adhesive area; A laminated metal plate with excellent vibration damping properties, which is interposed between the layers, has a thickness smaller than the thickness of the resin layer, and has an area ratio expressed by the following formula in the range of 25% or more and 98% or less. .

(2) In a laminated metal plate formed by sandwiching and fixing a resin layer between metal plates, the metal plate and the resin layer = the gap and the adhesive area, and the resin layer does not exist in the gap, and the following formula A laminated metal plate with excellent vibration damping properties, characterized in that the area ratio represented by is in the range of 25% or more and 98% or less.

Function The present invention has been made based on the discovery that damping properties can be imparted to a laminated metal plate by providing a void in the joint surface between the skin metal plate and the resin layer.

That is, according to experiments by the present inventors, for example, a 0.2 mm steel plate (SPB-TI) is used as the two skin metal plates, and an adhesive polypropylene sheet manufactured by Ube Industries is used as the core material, and the total thickness is 0.9 + am. A laminated steel plate was manufactured by hot pressing so that the following was obtained. In this case, the voids were created by cutting out the resin film in advance at the locations where the voids were to be formed, or by providing depressions in the resin film and hot-pressing the resin film with a steel plate. If the horizontal axis is the percentage (%) of the total area of the voids (total area of the voids + total area of the bonded parts), and the vertical axis is the loudness of the hitting sound (dB (C)), then Figure 2 shows As shown, 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. In the figure, the mark indicates that the resin layer 8 does not exist in the void 9 as shown in FIG. 4 (2), and the O mark indicates that the resin layer 8 exists in the void 9 as shown in FIG. 4 (1). This is the case. Note that 7 indicates a skin metal plate.

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.

Also, the above area ratio and bending stiffness kg* mm2/mm
) was investigated, and as shown in FIG. 3, it was found that good rigidity was exhibited at 88% or less.・, O marks are the same as in Fig. 2.

The bending stiffness was measured in accordance with ASTM D-790 using a specimen having a medium diameter of 50 mm, a length of 150 mm, and a bending span of 100 mm.

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% void space.

Moreover, as a limit to -, the area ratio is 98% as a range in which a decrease in bending rigidity is allowable.

Furthermore, although there are two spaces between the metal plate and the resin layer, in the present invention, if there is a gap between the metal plate and the resin layer, at least one of the bonding surfaces must have a gap. Bye. Of course, there is no problem in having a gap between the upper and lower joining surfaces.

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. Further, a steel plate or a striped steel plate with an uneven surface may be used. Furthermore, two different types of metal plates may be used simultaneously for the two skins. The thickness of the plate is determined depending on the use and desired performance and is not limited, but is typically about 0.1 to 2 mm+.

In addition, the S+ resin used as the core material includes polyolefins such as polypropylene, polyethylene, and poly4-methylpentene-1, which are commonly used in laminated metal plates.
Examples include polyvinyl chloride polymers, cellulose polymers, polyamides such as nylon, polyesters such as polyethylene terephthalate, polycarbonates, epoxy resins, acrylic resins, polyurethanes, and modified resins described in ``-'' (Japanese Patent Application Laid-Open No. 55-158052, etc.). ). Further, the thickness of the resin layer, like the thickness of the skin metal plate, is determined depending on the use and desired performance and is not limited, but is typically about 0.05 to 5 mm.

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). .

Furthermore, as a method for providing voids, the resin film is made to have concavities and convexities in a predetermined pattern during the production of the resin film. Further, after manufacturing the resin sheet, it is possible to punch holes in a predetermined pattern by punching or the like.

When vibration occurs, the skin metal plate vibrates in this gap, and the vibration energy is converted into thermal energy by compression and expansion of the air layer in the gap between the metal plate and the resin layer, or in the gap where there is no resin. It is thought that the vibration damping effect is achieved by converting it into

Next, although the size and shape of the voids are not particularly limited, it is necessary that the voids and the adhesive portions are arranged alternately. That is, it is necessary that the voids are randomly arranged in the bonded portion (or the bonded portion is in the void).

Examples of the arrangement are illustrated in FIGS. 5 to 8. The shaded areas indicate voids, and the blank spaces indicate bonded areas.

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 gap is provided between the metal plate and the resin layer. There are three shapes of the void portion or the bonded portion: square, circular, and rectangular.

Table 3 shows examples in which there is no resin layer in the void. There are three shapes of the void portion or the bonded portion: square, circular, and rectangular.

For the surface metal plate, apply 2 coats of weak alkaline degreasing liquid to the steel plate.
m1n, for pure aluminum plate, 1 with 3% NaOH aqueous solution
0mln, for copper plate 2 with 10% HNO3 aqueous solution
Degreased samples were used.

The resin and the metal plate are fixed by hot pressing method. When polypropylene (PP) is used, the hot pressing conditions are as follows: Raise the temperature to 180℃, hold 2mln, and then press 13mm.
Cool to 0℃, raise the temperature to 220℃ when using nylon-6 (NY), maintain 2 win, then 140℃
It was cooled until. The pressure of the hot press is always 2 kg/
It was cffi2.

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

(Hereinafter in the margin) Effects of the Invention As explained, according to the present invention, it is possible to reduce the weight of a laminated metal plate while maintaining high specific stiffness (bending stiffness/specific gravity) and imparting vibration damping properties. can.

[Brief explanation of drawings]

Figure 1 is an elevational view explaining the method for measuring hitting sound, Figure 2 is a diagram showing the relationship between the area ratio of the void and the magnitude of the hitting sound, and Figure 3 is the relationship between the area ratio of the void and the bending stiffness. Relationship diagram, Figure 4 (1)
, (2) are cross-sectional views of the laminated metal plate of the present invention when a resin layer is present in the void and when no resin layer is present, respectively, and FIGS. 5 to 8 are explanatory diagrams showing the shape of the void. 1--Wall, 2--Knife Tsuji, 3--Test panel, 4--Steel ball, 51I--Mic, 6--Fist--Analyzer, 7--Skin metal plate, 8φ--Core material (resin layer), 9... void.

Claims (1)

[Claims] (1) In a laminated metal plate formed by sandwiching and fixing a resin layer between metal plates, the bonding surface between the metal plate and the resin layer is composed of a gap and an adhesive area, and the gap between the metal plate and the resin is formed in the gap. interposed in between, and its thickness is smaller than that of the resin layer,
A laminated metal plate with excellent vibration damping properties, characterized in that the area ratio expressed by the following formula is in the range of 25% or more and 98% or less. Area ratio (%) = total area of voids / (total area of voids + total area of adhesive parts) x 100 (%) (2) In a laminated metal plate in which a resin layer is sandwiched and fixed between metal plates,
The bonding surface between the metal plate and the resin layer is composed of a void and an adhesive, there is no resin layer in the void, and the area ratio expressed by the following formula is within the range of 25% or more and 98% or less. A laminated metal plate according to claim (1). Area ratio (%) = total area of voids / (total area of voids + total area of adhesive parts) x 100 (%)