Panel for railroad vehicle

Abstract

To provide a panel for a railroad vehicle light in weight and excellent in sound insulation performance.SOLUTION: A panel 100 a railroad vehicle is provided with core material 1, and a first plate 21 and a second plate 22 sandwiching the core material 1 therebetween. The core material 1 is formed of foaming resin, and at least one of the first plate 21 and the second plate 22 is formed of magnesium alloy, and shear modulus of the foaming resin is 20 MPa or more and 110 MPa or less.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The technology disclosed herein relates to railroad car panels. [Background technology]

[0002] Patent Document 1 discloses a floor panel for a railway vehicle that can reduce noise. The floor panel includes a core layer, a first plate material and a second plate material arranged on both sides of the core layer, and an elastic material layer that bonds the core layer to the first plate material and the second plate material. The elastic material layer has a Young's modulus of 1 MPa or more and 10 MPa or less, and a thickness of 0.1 mm or more and 1.0 mm or less. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2005-239014 A Summary of the Invention [Problem to be solved by the invention]

[0004] Railway vehicle panels are required to be lightweight in order to increase the speed of the vehicles. In addition, if a railway vehicle panel has poor sound insulation performance against noise generated outside the vehicle, passengers will feel uncomfortable. Therefore, railway vehicle panels are also required to have high sound insulation performance. However, simply reducing the weight of a railway vehicle panel may result in a decrease in sound insulation performance.

[0005] The technology disclosed herein has been made in consideration of the above points, and has an object to provide a railway vehicle panel that is lightweight and has high sound insulation performance. [Means for solving the problem]

[0006] The railway vehicle panel disclosed herein comprises a core material, and first and second plates sandwiching the core material, the core material being formed from a foamed resin, at least one of the first and second plates being formed from a magnesium alloy, and the shear modulus of the foamed resin being 20 MPa or more and 110 MPa or less. Effect of the Invention

[0007] The railroad vehicle panel is lightweight and has high sound insulation performance. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic vertical cross-sectional view of a railway vehicle panel. [Diagram 2] FIG. 2 is a conceptual diagram showing the relationship between acoustic frequency and acoustic transmission loss. [Diagram 3] FIG. 3 is a graph showing the measurement results of sound transmission loss according to the example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Exemplary embodiments will now be described in detail with reference to the accompanying drawings, in which: FIG 1 is a schematic longitudinal sectional view of a panel 100 for a railway vehicle.

[0010] The railway vehicle panel 100 (hereinafter simply referred to as "panel 100") is a so-called sandwich panel. The panel 100 is used as an interior material for railway vehicles. The panel 100 is used, for example, in the ceiling, upper floor board, inner end partition, etc. of railway vehicles. The panel 100 comprises a core material 1, and a first plate 21 and a second plate 22 that sandwich the core material 1. The panel 100 may further comprise an adhesive 3.

[0011] The core material 1 improves the sound insulation performance of the panel 100. The core material 1 is made of a foamed resin. The material of the foamed resin is not limited as long as it satisfies the shear modulus described below, but the core material 1 is preferably made of a PET resin foam, a polystyrene foam, a hard acrylic foam, or a polyolefin foam.

[0012] If the shear modulus of the foamed resin of the core material 1 is less than 20 MPa, the bending rigidity and compressive strength of the panel 100 will be insufficient. On the other hand, if the shear modulus of the foamed resin exceeds 110 MPa, the sound insulation performance of the panel 100 will be insufficient. Therefore, the shear modulus of the foamed resin is 20 MPa or more and 110 MPa or less. This ensures the bending rigidity and compressive strength of the panel 100 and achieves the desired sound insulation performance. From the viewpoint of bending rigidity and compressive strength, the shear modulus of the foamed resin is preferably 25 MPa or more, more preferably 30 MPa or more, and even more preferably 35 MPa or more. From the viewpoint of sound insulation performance, the shear modulus of the foamed resin is preferably 100 MPa or less, more preferably 75 MPa or less, even more preferably 60 MPa or less, and even more preferably 40 MPa or less. The shear modulus of the foamed resin can be measured by cutting a test piece having a length of 150 mm and a width of 20 mm from the foamed resin in accordance with ASTMC273. When cutting the test piece from a sheet-shaped foamed resin, the thickness of the test piece may be the thickness of the sheet itself. The thickness of the test piece is, for example, in the range of 12 mm to 20 mm.

[0013] The foaming ratio of the foamed resin of the core material 1 is preferably 3 times or more, and more preferably 10 times or more. This can further improve the light weight of the panel 100. The foaming ratio is a value obtained by dividing the volume of the uncured foamed resin after foaming by the volume of the uncured foamed resin before foaming. The foaming ratio of the foamed resin is preferably 30 times or less, and more preferably 20 times or less. This can improve the strength of the panel 100.

[0014] The density of the foamed resin of the core material 1 is preferably 200 kg / m 3 Less than 100kg / m is more preferable. 3Less than or equal to 80 kg / m 3 This can further improve the light weight of the panel 100. The density of the foamed resin is preferably 30 kg / m 3 More preferably, 50 kg / m 3 More preferably, 60 kg / m 3 More preferably, 70 kg / m 3 This makes it possible to improve the strength of the panel 100. The density of the foamed resin can be measured in accordance with JIS K 7222 by cutting a test piece of width 50 mm, length 50 mm and thickness 20 mm from the foamed resin.

[0015] The thickness t1 of the core material 1 is preferably 3 mm or more, and more preferably 8 mm or more. This can improve the processability of the core material 1. The thickness t1 is preferably 40 mm or less, and more preferably 25 mm or less. This can further improve the lightweight nature of the panel 100.

[0016] At least one of the first plate 21 and the second plate 22 is made of a magnesium alloy. When one of the first plate 21 and the second plate 22 is made of a magnesium alloy, the other of the first plate 21 and the second plate 22 may be made of a lightweight metal other than a magnesium alloy. For example, the other of the first plate 21 and the second plate 22 may be made of aluminum.

[0017] The thickness t2 of each of the first plate and the second plate is preferably 0.3 mm or more, and more preferably 0.5 mm or more. This can improve the strength of the panel 100. The thickness t2 is preferably 2.5 mm or less, and more preferably 1.5 mm or less. This can further improve the lightness of the panel 100.

[0018] The density of the magnesium alloy is preferably 1.9 g / cm 3 This can further improve the light weight of the panel 100. The density of the magnesium alloy is preferably 1.7 g / cm3 This makes it possible to improve the strength of the panel 100.

[0019] The adhesive 3 bonds each of the first plate 21 and the second plate 22 to the core material 1. There are no limitations on the adhesive 3 as long as it can bond each of the first plate 21 and the second plate 22 to the core material 1. The adhesive 3 is, for example, an elastic adhesive, an acrylic adhesive, a urethane adhesive, or the like.

[0020] An example of a manufacturing method for the panel 100 will be described. For example, first, adhesive 3 is applied to both sides of the core material 1, and then the first plate 21, the core material 1, and the second plate 22 are laminated together. Thereafter, the laminate is heated and pressurized simultaneously to form the panel 100 using, for example, a hot press device or an autoclave device.

[0021] In such a panel 100, at least one of the first plate 21 and the second plate 22 is formed from a magnesium alloy, which allows the panel 100 to be lightweight. Furthermore, since the shear modulus of the foamed resin of the core material 1 is 20 MPa or more and 110 MPa or less, the panel 100 can achieve high sound insulation performance. In this way, the panel 100 can achieve both light weight and high sound insulation performance.

[0022] Specifically, the inventors considered that the weight of the panel 100 could be reduced by reducing the amount of the first plate 21 and the second plate 22, which account for a large proportion of the weight of the panel 100. However, simply reducing the thickness of each of the first plate 21 and the second plate 22 may reduce the strength of the panel 100. As a result of intensive research by the inventors, the inventors found that the weight of the panel 100 can be reduced while maintaining the strength of the panel 100 by using a magnesium alloy with a relatively low density as the first plate 21 and the second plate 22 at the same thickness as that of the conventional plate (e.g., aluminum). However, since the weight of the panel 100 is reduced, the sound insulation performance may be reduced. As a result of intensive research by the inventors, the inventors found that the reduction in the sound insulation performance can be compensated for by setting the shear modulus of the foamed resin of the core material 1 to 20 MPa or more and 110 MPa or less. Specifically, the inventors found that, regardless of the material of the foamed resin of the core material 1, the sound insulation performance can be improved as the shear modulus of the foamed resin is reduced.

[0023] The mechanism by which sound insulation performance can be improved by reducing the shear modulus of the foamed resin of the core material 1 is not necessarily clear. However, the inventors currently believe this mechanism to be as follows. FIG. 2 is an explanatory diagram for explaining this mechanism. In detail, FIG. 2 is a conceptual diagram showing the effect of differences in the shear modulus of the foamed resin on sound transmission loss (TL). Sound transmission loss is a parameter that represents sound insulation performance. Sound transmission loss represents the amount of reduction in the energy of transmitted sound relative to incident sound. It can be said that the greater the sound transmission loss, the better the sound insulation performance of the material.

[0024] In FIG. 2, the graph indicated by the symbol C1 (hereinafter simply referred to as "C1") and the graph indicated by the symbol C2 (hereinafter simply referred to as "C2") show the relationship between the acoustic frequency and the acoustic transmission loss in a foamed resin. The shear modulus of the foamed resin of C2 is lower than that of the foamed resin of C1. The foamed resins of C1 and C2 have the same conditions (e.g., mass, etc.) other than the shear modulus. Each of C1 and C2 has two frequencies ω1 and ω2 that are inflection points. Here, ω2 is expressed by the following formula (1). ω2=G c ×t c / (m×B3) 1 / 2 (1) However, G c :Shear modulus [Pa], t c : thickness of core material [m], m: surface density of entire panel [kg / m 2 ], B3: Bending rigidity of the entire panel (range above ω2) [Nm]

[0025] As can be seen from the above formula (1), the shear modulus G c When the shear modulus becomes lower, ω2 becomes lower. That is, as shown in FIG. 2, the ω2 of C2, which has a low shear modulus, becomes lower than the ω2 of C1, which has a high shear modulus, and C2 is shifted generally to the lower frequency side than C1. As a result, as shown by the double-headed arrow in FIG. 2, a frequency range is generated in which the sound transmission loss is improved in C2 compared to C1. It is considered that the improvement in sound transmission loss increases as C1 is shifted generally to the lower frequency side, that is, as the shear modulus becomes lower. That is, the sound insulation performance can be improved by reducing the shear modulus of the foamed resin of the core material 1. EXAMPLES

[0026] The relationship between the shear modulus of the core material and the sound transmission loss was investigated. The core materials used in Comparative Example 1 and Examples 1 to 5 are shown in Table 1. The product names or tentative names of the developed products are shown in Table 1. The shear modulus of the core material was measured in accordance with ASTMC273 as described above. The density of the core material was measured in accordance with JIS K 7222 as described above. The measurement results are shown in Table 1. The core material in Comparative Example 1 is so-called balsa wood. The core materials in Examples 1, 2, 4, and 5 are an example of a hard acrylic foam, an example of a polyolefin foam, an example of a PET resin foam, and an example of a polystyrene foam, respectively. The core material in Example 3 is a developed product, specifically a polypropylene foam with nonwoven fabric.

[0027] [Table 1]

[0028] Next, the sound transmission loss was measured for each of Examples 1 to 4. For each of Examples 1 to 4, a magnesium alloy was used for the first and second plates. The thickness of the first plate was 1.0 mm. The thickness of the second plate was 0.5 mm. For each of Examples 1 to 4, the thickness of the core material was 20 mm. The sound transmission loss was measured by a sound insulation performance test in accordance with JIS A 1416 ("Method of measuring sound transmission loss in a laboratory"). In the measurement, the sound source was installed on the second plate side, and the measuring device was installed on the first plate side. The measurement results are shown in FIG. 3. The frequency band that can be targeted in a railway vehicle is about 400 Hz to 1600 Hz. Therefore, it is preferable to improve the sound transmission loss in this frequency band. In a railway vehicle, the pass standard for sound transmission loss is, for example, 20 dB or more at 400 Hz and 20 dB or more at 800 Hz.

[0029] The results of the investigation will be considered. As shown in Table 1, the densities of Examples 1 to 4 are approximately the same (areal density of approximately 7 kg / m 2) in the order of shear modulus of Example 1 to Example 4. Although the densities of Example 1 to Example 4 are similar, as shown in FIG. 3, the sound transmission loss tends to increase in the order of Example 1 to Example 4, that is, as the shear modulus decreases, and it can be seen that the sound insulation performance is improved. The sound transmission loss of Example 1 to Example 4 all met the pass standard of "20 dB or more at 800 Hz". In particular, Example 2 to Example 4 all met the pass standard of "20 dB or more at 400 Hz". On the other hand, since Comparative Example 1 has a higher shear modulus than Example 1, it is presumed that the sound transmission loss does not meet the pass standard of "20 dB or more at 800 Hz".

[0030] The techniques disclosed herein can be summarized as follows:

[0031] [1] A railway vehicle panel 100 comprises a core material 1, and a first plate 21 and a second plate 22 sandwiching the core material 1, the core material 1 being formed from a foamed resin, at least one of the first plate 21 and the second plate 22 being formed from a magnesium alloy, and the shear modulus of the foamed resin being 20 MPa or more and 110 MPa or less.

[0032] According to this configuration, at least one of the first plate 21 and the second plate 22 is formed from a magnesium alloy, which can reduce the weight of the railway vehicle panel 100. Furthermore, by setting the shear modulus of the foamed resin to 20 MPa or more and 110 MPa or less, it is possible to compensate for the decrease in sound insulation performance that accompanies the weight reduction of the railway vehicle panel 100. In other words, it is possible to realize a railway vehicle panel 100 that is lightweight and has high sound insulation performance.

[0033] [2] In the railway vehicle panel 100 described in [1], the core material is made of a PET resin foam, a polystyrene foam, a hard acrylic foam, or a polyolefin foam.

[0034] According to this configuration, a foamed resin having a shear modulus of elasticity of 20 MPa or more and 110 MPa or less can be realized. [Explanation of symbols]

[0035] 100 Railroad vehicle panels 1 Core material 21 1st board 22 2nd board 3. Glue

Claims

1. A core material; A first plate and a second plate sandwiching the core material therebetween, The core material is formed of a foamed resin, At least one of the first plate and the second plate is formed of a magnesium alloy, The shear modulus of the foamed resin is 20 MPa or more and 110 MPa or less.

2. The railroad vehicle panel according to claim 1, The core material is a railway vehicle panel formed of a PET resin foam, a polystyrene foam, a hard acrylic foam, or a polyolefin foam.

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