JPH05171601A - Track pad - Google Patents

Abstract

PURPOSE:To obtain a track pad to be set between sleepers and rails of railroad track, having excellent durability, excellent weather proofness, excellent vibration absorbability, and spring constant. CONSTITUTION:A track pad 1 is formed of an elastic sheet having many spherical spaces 2 sealed from outside, uniformly dispersed, and not connected to each other inside. The track pad 1 having excellent durability, excellent weather proofness, low spring constant, and no defects caused by packing foreign matters out the surface due to absence of recessions can thus be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a track pad laid between a rail and a sleeper in a railway track.

[0002]

Track pads have been conventionally used for the purpose of preventing vibration of rails during running of railway vehicles, preventing noise caused by the vibrations, and preventing damage to concrete sleepers, especially for bullet trains. With the development of high-speed railway, the problem of noise prevention has been greatly highlighted,
Various improvements and proposals have also been made for track pads.

Generally, in order to prevent noise caused by vibration, it is known that a material (damper) having a small elastic coefficient, such as rubber, may be interposed between the vibration source and a fixing portion supporting the vibration source. For the above-mentioned track pad, a soft rubber plate or a sponge rubber plate is used, and in order to make it easily deformable, a groove is formed on the lower surface of the seat or a through hole is formed (for example, the actual opening 48 -7904) has been proposed.

[0004]

By the way, in recent years, there has been an increasing demand for noise prevention and the like, and in order to reinforce the demand, the track pad is made of a material having a higher vibration absorption property, and therefore is more easily manufactured. The use of highly deformable elastic materials has become necessary. However, since the track pad is to be continuously used for a long period after being laid, it has sufficient durability and weather resistance, and
Since it is necessary for the compression set and the change in elastic modulus to be small, it is not easy to provide a track pad that can satisfy the above requirements.

For example, soft rubber or sponge rubber having a smaller elastic coefficient has a problem that the physical properties such as tear strength are insufficient and the durability is poor. Also, the above-mentioned sheet provided with grooves and through holes is excellent in that it can structurally relax the requirement for easy deformation of the rubber material itself, but in actual use, this track pad is used outdoors. As a result, the groove or the through hole is clogged with foreign matter, resulting in a decrease in elasticity, or stress concentration occurs in the corner portion of the groove or the through hole, which easily causes breakage and has a problem in durability.

The present inventor has solved the problems of the conventional track pad as described above, and has developed a track pad having excellent durability and weather resistance, and having a higher vibration absorption property required recently. The present invention has been made for the purpose of providing.

[0007]

The feature of the track pad of the present invention is that it has a large number of externally sealed small voids.
Preferably, the spherical voids are arranged in the sheet-like member in a substantially even manner.

In the above-mentioned sealed type void, providing the void as a large void causes unevenness in the elasticity of the pad to be unevenly distributed. Therefore, it is necessary to provide a large number of voids having an appropriate small size. Although the size of the void is not particularly limited, it is generally about 6 mm to 16 mm in inner diameter, preferably about 10 mm to 14 mm.

The large number of voids inside the seat preferably form independent air chambers that do not communicate with each other. A sheet-like orbital pad having such a void is manufactured by, for example, a method in which a sheet having a recess formed by dividing the pad in the thickness direction is overlapped and integrated so that the recesses are aligned. can do. Further, a rubber ball may be embedded inside the sheet-shaped member in order to form a void.

[0010]

The track pad of the present invention is structurally constructed as a sheet-like member having a low spring constant due to the existence of a void inside the seat, and the need for using a material having low mechanical strength for the rubber itself is alleviated. There is an effect that is done.

Further, since the void is not opened on the surface of the sheet, there is an effect that the spring constant is not increased due to the clogging of foreign matter.

In addition, when the void is formed in a spherical shape, the influence of stress concentration is alleviated as compared with the case of having an edge shape, and there is an effect that durability is advantageous.

[0013]

EXAMPLES The present invention will be further described below with reference to examples.

Example 1 Using a natural rubber material, an orbital pad 1 (140 × 180 × 20 mm) made of a natural rubber sheet having a large number of spherical cavities 2 having an inner diameter of 14 mm provided at intervals of 8 mm was manufactured. The spring constant was 20 t / cm.

Example 2 The same natural rubber material as in Example 1 was used, with an inner diameter of 30
An orbital pad 3 (140 × 180 × 20 mm) made of a natural rubber sheet in which a large number of × 30 × 30 mm flat rectangular cavities 4 were separated by 10 mm partition walls 5 was manufactured. A radius of 2 mm was attached to the side of the void 4. Spring constant is 2
It was 0 t / cm.

Comparative Example A track pad 6 having the same shape as that of Example 1 except that the same natural rubber material as in Example 1 was used and no spherical cavity was provided was manufactured. The spring constant was 40 t / cm.

Regarding the orbital pad of each example, JISK6
The change rate of heat aging for 70 hours at 100 ° C. according to 301 was measured, and the results are shown in Table 1 below.

[0018]

[Table 1]

As can be seen from these results, in the case of the same compressive elastic modulus, the spring constant of the raceway pad was lower in the example than in the comparative example, and the change in physical properties after heat aging was smaller in the example than in the comparative example.

[Brief description of drawings]

FIG. 1 is a sectional view of a track pad according to a first embodiment of the present invention in which a soft rubber sheet is provided with a spherical space.

FIG. 2 is a plan view of the track pad according to the first embodiment.

FIG. 3 is a cross-sectional view of a track pad according to a second embodiment of the present invention in which a flat rectangular space is provided inside a soft rubber sheet.

FIG. 4 is a plan view of the track pad according to the second embodiment.

FIG. 5 is a cross-sectional view of a conventional track pad made of solid rubber having no space inside.

[Explanation of symbols]

1, 3, 6: orbital pad, 2: spherical void, 4: flat rectangular void, 5: bulkhead.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Isao Endo 348 Kashiwa-shi, Chiba Prefecture 348 Showa Rubber Co., Ltd. Kashiwa Plant (72) Inventor Hiromichi Kimura 348 Kashiwa-shi Chiba Prefecture 348 Inside Kashiwa Plant

Claims (2)

[Claims] 1. A track pad, characterized in that a large number of small voids sealed from the outside are arranged substantially evenly inside a sheet-shaped member. 2. The track pad according to claim 1, wherein the void is spherical.