JPH04238902A - soundproof rail - 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]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a soundproof rail that effectively and economically reduces the noise generated from the rail when a train passes by.

0002

[Conventional technology] Conventionally, regarding the problem of train noise prevention, since the opening of the Tokaido Shinkansen, the former National Railways Railway Technology Research Institute has been playing a central role in tackling noise prevention technology on a large scale, and the noise environment standards, including the track bed structure, have been cleared. The technology has been established. However, in recent years, with the trend toward higher efficiency in railway transportation, increasing the speed of trains has become a top priority, and efforts are being made to gradually increase the speed of not only Shinkansen trains but also conventional lines.

[0003] However, from recent experiments to increase the speed of trains,
As things stand now, trains cannot pass the noise environment standards, which is hindering the speeding up of trains, and train noise prevention technology has re-emerged as a major issue. It is said that the main source of train noise is the contact noise between the rails and wheels, and various efforts have been made to develop rail noise prevention technologies.

[0004] For example, the literature ``Rail; written by Yashuo Kato, published by Japan Railway Facilities Association, January 30, 1978, 111-1
As shown in Figures 4, 5, and 6 on page 13, a soundproof rail has been developed in which a synthetic (elastic) resin is glued to a part of the rail, or the belly and bottom of the rail are covered with elastic resin. It has been reported that the effect of reducing noise has been recognized.

However, it has not been put into practical use due to problems such as insufficient noise prevention effect and high cost.

[0006]

[Problems to be Solved by the Invention] Therefore, with the aim of providing a soundproof rail, the present inventors measured the noise during actual train passing, and analyzed the frequency characteristics of the frequency bands that are mainly responsible for the noise. is relatively low frequency range and high frequency range.
It was discovered that the soundproofing effect would be small unless measures were taken to attenuate both bands.

On the other hand, methods such as changing the rail material or changing the rail rigidity can be considered as soundproofing measures for the rail, but these are impractical, so the inventors of the present invention injected urethane elastomer (elastic resin) into the rail. Alternatively, we considered a coating method. To confirm the soundproofing effect, we established a rail sounding method that generates each frequency band involved in noise, and measured vibration damping at the rail abdomen and rail bottom using this sounding method, and a distance of 50 cm horizontally from the sounding position. As a result of conducting various experiments to investigate the effectiveness of soundproofing measures by measuring noise at distant locations, we obtained the following knowledge.

(1) The belly of the rail near the contact surface with the wheels emits noise levels in a high frequency range, and the bottom of the rail emits noise levels in a relatively low frequency range. (2) There is a big difference in the noise generated when hitting the rail, depending on the hardness of the urethane elastomer that coats the rail. (3) Soft urethane has the property of absorbing vibration waves in a high frequency range well, and hard urethane has a property of well absorbing vibration waves in a low frequency range.

(4) A two-layer coating material in which the interface side with the rail is coated with soft urethane and the outer side is coated with hard urethane has the greatest soundproofing effect. Based on these findings, the present inventors found the most effective soundproofing measure by coating the whole or part of the rail, excluding the top and side surfaces of the rail, with soft urethane on the interface side with the rail, and coating the outside with hard urethane. The present invention provides a two-layered rail coated with urethane.

0010

[Means for Solving the Problems] The present invention has been made based on the above findings, and its gist is to provide a soft urethane elastomer coating on the lower part of the head and upper neck of the rail, at least from the upper neck to the abdomen. The soundproof rail is characterized in that a hard urethane elastomer coating layer is applied between the layers.

The present invention will be explained in detail below with reference to the drawings. Figure 1 shows the rails. First, for convenience of explanation, the names of each part of the rail will be described. In Fig. 1, the range 1 is the top of the head, the range 2 is the side of the head, the range 3 is the upper neck, the range 4 is the abdomen, the range 5 is the upper surface of the bottom, the range 6 is the side of the bottom,
The range 7 is the lower surface of the bottom. 2 and 3 are cross-sectional views of one embodiment of the rail of the present invention. In the rails shown in FIGS. 2 and 3, reference numeral 8 is a soft urethane elastomer that covers at least the upper neck portion 3 to the abdomen 4 of the rail. Figure 2
3 shows an example in which the area from the upper neck part 3 to the abdomen 4 is covered with a soft urethane elastomer 8, and FIG. A hard urethane elastomer 9 is coated below the upper neck portion 3 of the rail with a soft urethane elastomer 8 covering layer interposed therebetween.

[0012] In the present invention, urethane elastomer was selected as the material for covering the rails as described above because urethane is an elastomer that cures at room temperature, so it is easy to spray paint or inject into molds, and the amount of curing agent added is This is because the hardness can be easily controlled and it is cheaper than other coating methods. In addition, the interface side with the rail is coated with a soft urethane elastomer,
The reason for coating the outside with two hard layers of urethane elastomer is as follows.

The soft urethane elastomer coating layer absorbs vibration waves well and has the effect of damping vibration waves in a high frequency range. Therefore, the high frequency vibration of the rail abdomen 4 is attenuated by the coating layer of the soft urethane elastomer 8 at least from the upper neck portion 3 to the abdomen 4 of the rail. In addition, the outer hard urethane elastomer coating layer 9 absorbs vibration waves that could not be absorbed by the soft urethane elastomer coating layer 8 and further attenuates them, further enhancing the soundproofing effect and improving scratch resistance. There is also.

The hardness values of the soft and hard materials are not particularly limited, but it goes without saying that the larger the difference in hardness between the soft materials and the hard materials, the greater the soundproofing effect. Considering other mechanical properties, Shore hardness difference is 20 to 30
It has good weather resistance and mechanical properties, and has a great soundproofing effect, making it practical. Furthermore, there is no particular limitation on the coating thickness of each of the two layers, but a better soundproofing effect can be seen when the ratio of the thickness of the soft part to the hard part is in the range of 1:6 to 1:1. .

[0015]Although there is no particular limitation on the coating thickness of the two layers as a whole, a range of 2 mm to 10 mm is practically appropriate considering economic efficiency and the effect on high-speed running of trains. Note that the rail of the present invention coated with urethane elastomer not only has the effect of preventing noise, but also has an extremely large effect as a corrosion-proofing rail since urethane has sufficient corrosion resistance. Furthermore, urethane is effective against electrolytic corrosion of the rail due to leakage of signal current because it has a large insulation resistance, and also has the performance as an electrolytic corrosion-resistant rail.

[0016]

[Example] Specific examples will be described below. In order to confirm whether the rail of the present invention has sufficient performance as a soundproof rail, the rail of FIG. 2 and the rail of FIG. Select soundproof rails with a urethane elastomer coating layer, and
Prepare a rail of m length, hang both ends of the rail with a string, and use a hammer with a weight of 200g to attach the head in the center of the length of the rail.
The sample was allowed to fall freely from a height of 1.5 cm, and the generated noise was measured using a sound level meter. Note that the microphone for noise measurement was set to match the rail height position and horizontally 50 cm away from the hitting point. All rails used were JIS 60, which is the same used in Shinkansen trains.

Table 1 shows the noise measurement results for each rail. In the case of the comparison rail, the maximum noise level of the non-soundproofed rail is 95 dB and the maximum noise level of the soundproof rail is 89 dB, whereas the maximum noise level of the rail of the present invention shown in Fig. 3 is 7.
It has an extremely excellent soundproofing effect of 8 dB, and the rail of FIG. 2 also has a maximum noise level of 81 dB, indicating that the rail of the present invention has excellent soundproofing performance.

[0018]

[Table 1]

[0019]

Effects of the invention: As a result of measuring the noise generated when a hammer with a weight of 200 g is freely fallen onto a rail from a height of 30 cm, the noise generated by the rail of the present invention was 78 to 81 dB, compared to the uncoated rail for comparison without any coating layer. was 95 dB, confirming that the rail of the present invention has a high soundproofing effect.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a rail for explaining the names of each part of the rail.

FIG. 2 is a sectional view showing one embodiment of the rail of the present invention.

FIG. 3 is a sectional view showing one embodiment of the rail of the present invention.

FIG. 4 is a perspective view of a conventional soundproof rail in which a synthetic (elastic) resin is bonded to a portion of the rail.

FIG. 5 is a cross-sectional view of the rail of FIG. 4;

FIG. 6 is a cross-sectional view of a conventional soundproof rail in which a portion of the rail is coated with an elastic resin.

Claims (1)

[Claims] 1. A soundproof rail characterized in that a hard urethane elastomer coating layer is applied below the head and upper neck of the rail through a soft urethane elastomer coating layer at least from the upper neck to the abdomen.