JP2023171022A - Sleeper pad and manufacturing method thereof - Google Patents

Abstract

To provide a sleeper pad having both of vibration control performance and durability.SOLUTION: A sleeper pad (10), when a face coming into contact with a face of the sleeper (20) is set as a contact face (15) and the direction prescribing the contact face (15) is set to a first direction and a second direction, has multiple first extension parts (11) extended in the first direction and multiple second extension parts (12) extended in the first direction and having a smaller spring constant than the first extension part (11). Each of the multiple first extension parts (11) and each of the multiple second extension parts (12) are adjacently arranged in the second direction.SELECTED DRAWING: Figure 2

Description

The present invention relates to a sleeper pad and a method for manufacturing a sleeper pad.

Sleeper pads are provided on sleepers that make up train tracks, etc., for the purpose of reducing vibration. The sleeper pad is provided, for example, on the underside of the sleeper between the sleeper and the ballast stone, or on the upper side of the sleeper between the sleeper and the rail. Reducing vibration is important from the viewpoint of extending the life of the track and reducing noise.

For example, Patent Document 1 discloses that an intervening device is installed on the upper surface of a sleeper, etc., which includes a thin plate-shaped substrate portion molded from foamed rubber and a surface layer plate portion fixed to the upper surface of the substrate portion and molded from polyamide resin. A track pad is disclosed. Further, Patent Document 2 discloses a track pad having a base plate portion having a bottom surface with a recess and an upper surface without a recess in order to obtain a required spring constant.

Japanese Patent Application Publication No. 2015-224459 JP2006-265841A

The sleeper pad preferably has a low spring constant from the viewpoint of improving vibration damping performance. However, there is generally a problem that the spring constant and durability of a material are approximately proportional to each other, and if the spring constant is low, the durability is also low.

In view of such problems, one aspect of the present invention aims to realize a sleeper pad or the like that has both vibration damping performance and durability.

In order to solve the above problems, a sleeper pad according to one aspect of the present invention is a sleeper pad that is provided on the surface of the sleeper to reduce vibrations of the sleeper, and the sleeper pad is in contact with the surface of the sleeper. If the surface is a contact surface and the directions defining the contact surface are a first direction and a second direction, a plurality of first extending portions extending in the first direction and a plurality of first extending portions extending in the first direction and the first extending portion extending in the first direction are provided. a plurality of second stretched parts having a smaller spring constant than the stretched parts, each of the plurality of first stretched parts and each of the plurality of second stretched parts being adjacent to each other in the second direction. It is arranged like this.

In order to solve the above problems, a method for manufacturing a sleeper pad according to one aspect of the present invention is a method for manufacturing a sleeper pad that reduces vibrations of the sleeper by providing it on the surface of the sleeper, wherein the sleeper pad is provided on the surface of the sleeper to reduce vibrations of the sleeper. If the surface in contact with the surface of the sleeper is a contact surface, and the directions defining the contact surface are a first direction and a second direction, a plurality of first and second directions formed of a rubber material or a resin material and extending in the first direction and a plurality of second stretched parts formed of a rubber material or a resin material that are stretched in the first direction and have a spring constant smaller than that of the first stretched parts. , in the extrusion step, the first stretching section and the second stretching section are arranged such that each of the plurality of first stretching sections and each of the plurality of second stretching sections are adjacent to each other in the second direction. The parts are integrally molded by extrusion.

According to one aspect of the present invention, it is possible to realize a sleeper pad or the like that has both vibration damping performance and durability.

It is a schematic diagram showing an example of arrangement of a sleeper pad concerning one embodiment on a sleeper. It is a schematic diagram showing the composition of the sleeper pad concerning one embodiment. FIG. 3 is a schematic diagram showing a state in which the sleeper pad shown in FIG. 2 is placed on a ballast stone. FIG. 3 is a graph showing the relationship between the spring constant of the sleeper pad and the volume ratio of the first stretched portion and the second stretched portion according to one embodiment. It is a schematic diagram which shows the structure of the sleeper pad based on a modified example.

[Configuration of sleeper pad]
Hereinafter, one embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 1, the sleeper pad 10 according to the present embodiment is provided on the surface of the sleeper 20 to reduce vibrations of the sleeper 20.

As shown by the reference numeral 101 in FIG. 1, the sleeper 20 is a member that supports a rail R provided on a train track, for example. The sleepers 20 may be made of wood, or may be made of something other than wood, for example, concrete. Note that FIG. 1 only schematically illustrates the arrangement of the sleeper pads 10 and does not represent the specific shape of the sleeper pads 10. The specific shape of the sleeper pad 10 is illustrated in FIG. 2 and subsequent figures.

In the example indicated by reference numeral 102 in FIG. 1, the sleeper pad 10 is provided on the surface of the sleeper 20 on the lower side of the sleeper 20. In this case, the sleeper pad 10 is located between the sleeper 20 and the ballast stone B to reduce the vibration of the sleeper 20. In this case, by using the sleeper pad 10, in addition to reducing the vibration of the sleeper 20, the frequency of replacing the ballast stones B can also be reduced by reducing deterioration of the ballast stones B. Ballast stone B may be crushed stone, gravel, or the like.

The position of the sleeper pad 10 is not limited to this, and for example, the sleeper pad 10 may be provided on the sleeper 20 above the sleeper 20. In this case, the sleeper pad 10 is located between the sleeper 20 and the rail R to reduce the vibration of the sleeper 20.

(First stretching section and second stretching section)
As shown in FIG. 2, the sleeper pad 10 includes a plurality of first extending portions 11 and a plurality of second extending portions 12. In this specification, the width direction of the sleeper pad 10 will be described as the X direction, the longitudinal direction as the Y direction, and the up and down direction as the Z direction.

In this embodiment, the first direction and the second direction in the claims correspond to the Y direction and the X direction, respectively. Note that the first direction and the second direction in the sleeper pad 10 are not limited to these, and the sleeper pad 10 may be configured such that, for example, the first direction corresponds to the X direction and the second direction corresponds to the Y direction.

The X direction and the Y direction are directions that define the contact surface 15 when the surface of the sleeper pad 10 in contact with the surface of the sleeper 20 is the contact surface 15. As described above, in this embodiment, the sleeper pad 10 is provided on the surface of the sleeper 20 on the lower side of the sleeper 20. Therefore, the contact surface 15 of the sleeper pad 10 is in contact with the surface of the sleeper 20 on the lower side of the sleeper 20.

The first extending portion 11 and the second extending portion 12 are both formed to extend in the Y direction. The sleeper pad 10 is a plate-shaped member in which each of the first extending portions 11 and each of the second extending portions 12 are arranged adjacent to each other in the X direction.

The second stretched portion 12 has a smaller spring constant than the first stretched portion 11 . The spring constant is a value obtained by dividing the load applied to a material by the amount of compression deformation of the material due to the load. As used herein, a spring constant is intended to be a static spring constant. Further, since the spring constant changes depending on the size of the sleeper pad 10, it is preferable to compare the spring constant per unit area in order to compare materials. The values of spring constants in this specification are spring constants per square meter unless otherwise specified. It can be said that the larger the spring constant, the harder the material is difficult to deform. The compressive load value per unit area is an index of the hardness of the material, whereas the spring constant is the value obtained by dividing the compressive load value by the amount of deformation, so the spring constant can also be said to be an index of the hardness of the material. In this way, the spring constant is useful not only as an indicator of the hardness of the spring but also as an indicator of the hardness of the material. The spring constant is determined by the following formula (1);
Spring constant (N/mm) = load (N/m ² )/deformation amount (mm) (1).

The spring constant can be an index similar to the hardness of the material as described above, but is different from an index indicating the degree of elasticity of the material. The properties of a rubber material can be expressed by the ratio of elasticity to viscosity, but even if the ratio of elasticity to viscosity is different, the hardness of the material may be the same. Therefore, the ratio of elasticity and viscosity of a rubber material does not necessarily correlate with the hardness of the material. Therefore, even if two different types of materials have the same hardness (same spring constant), the ratios of elasticity and viscosity of these materials may be different from each other.

The first spring constant k1, which is the spring constant of the first stretching part 11, is not particularly limited as long as it is larger than the second spring constant k2, which is the spring constant of the second stretching part 12. The first spring constant k1 is preferably small from the viewpoint of vibration damping performance of the sleeper pad 10, and preferably large from the viewpoint of the durability of the sleeper pad 10. The first spring constant k1 may be adjusted as appropriate depending on the weight and size of the sleeper 20 on which the sleeper pad 10 is provided, the weight of the rail R, the weight and running frequency of trains etc. running on the rail R, etc. .

In order to evaluate the performance of the sleeper pad 10 and its respective members in actual use, it is preferable to measure the spring constant under conditions suitable for use on the ballast stone B. Therefore, to measure the spring constant, it is preferable to use a plate made by transferring the shape of ballast stone B, a compression jig described in European Committee for Standardization standard EN16730:2016, or the like.

For example, when measuring the overall spring constant kt, which is the spring constant of the entire sleeper pad 10, using a compression plate imitating the actual ballast stone B, the value is preferably within the range of 40 to 400 kN/mm, and more preferably. is preferably within the range of 100 to 350 N/mm. The compression plate used here may be, for example, a GBP (Geometric Ballast Plate), which is a compression jig described in the European Committee for Standardization standard EN16730:2016. At this time, the first spring constant k1 may be set to a larger value than the overall spring constant kt, and the second spring constant k2 may be set to a smaller value than the overall spring constant kt.

The sleeper pad 10 including the first stretching part 11 and the second stretching part 12 has an overall spring constant kt that is less than the first spring constant k1 and greater than the second spring constant k2. Generally, the smaller the spring constant of the material, the better the damping performance, but the softer the material, the lower the durability. Since it is preferable for the sleeper pad 10 to have a small overall spring constant kt from the viewpoint of vibration damping performance, it has been difficult to ensure durability with the conventional sleeper pad.

In the sleeper pad 10 according to this embodiment, the first extending portions 11 and the second extending portions 12 are arranged alternately. The load applied to the sleeper pad 10 tends to mainly act on the first stretched portion 11 which has a larger spring constant than the second stretched portion 12 and is less likely to deform. Therefore, for the sleeper pad 10, durability can be ensured to the same extent as the first stretched portion 11 while making the overall spring constant kt lower than the first spring constant k1 of the first stretched portion 11.

In this way, the sleeper pad 10 according to the present embodiment can achieve both high vibration damping performance and high durability. Therefore, the frequency of replacing the sleeper pads 10 can be reduced, and the amount of consumption of the sleeper pads 10 and the labor required for replacement can be reduced. This will also contribute to achieving Goal 12 of the Sustainable Development Goals (SDGs) led by the United Nations, such as "Ensure sustainable production and consumption patterns."

The first extending portion 11 and the second extending portion 12 are members each made of a material having a predetermined spring constant. The predetermined spring constant may be, for example, a value greater than 40 kN/mm and a value smaller than 400 kN/mm. Such a material may be, for example, a rubber material or a resin material. Examples of the rubber material include crosslinked rubber. Furthermore, examples of the resin material include thermoplastic resin materials.

Examples of crosslinked rubber include EPDM (ethylene-propylene-diene copolymer rubber), urethane rubber, butyl rubber, EPM (ethylene-propylene copolymer rubber), CR (chloroprene rubber), CM (chlorinated polyethylene), and CSM (chloroprene rubber). Sulfonated polyethylene), ACM (acrylic rubber), FKM (fluororubber), SBR (styrene-butadiene rubber) and NR (natural rubber). Examples of the thermoplastic resin material include TPE (thermoplastic elastomer), TPO (olefinic thermoplastic elastomer), and EVA (ethylene vinyl acetate).

From the viewpoints of durability, manufacturability, manufacturing cost, ease of procurement of materials, etc. of the sleeper pad 10, the material of the first stretched portion 11 and the second stretched portion 12 is preferably EPDM, urethane rubber, or CR, and EPDM is more preferable. preferable. Note that the material of the first stretched section 11 and the second stretched section 12 may contain a modifier such as a foaming agent.

The materials of the first stretched portion 11 and the second stretched portion 12 may be the same type of material, or may be mutually different types of materials. The difference in spring constant between the first stretched part 11 and the second stretched part 12 may be realized, for example, by using different materials, or by adjusting the material design such as the degree of polymerization of the materials. good. Further, the spring constant of the material may be adjusted by foaming the material.

For example, both the first stretched part 11 and the second stretched part 12 may be made of EPDM, and the first stretched part 11 may be made of non-foaming EPDM, and the second stretched part 12 may be made of foamed EPDM. . In this manner, in the sleeper pad 10, the first stretched portion 11 may be made of a non-foaming material, and the second stretched portion 12 may be made of a foamed material. According to the configuration, it is easy to design the sleeper pad 10 so that the second spring constant k2 has a smaller value than the first spring constant k1. Further, since it is easy to ensure the difference between the first spring constant k1 and the second spring constant k2, the degree of freedom in designing the overall spring constant kt of the sleeper pad 10 can be increased.

(Protrusion)
As shown in FIGS. 2 and 3, the sleeper pad 10 preferably has a convex portion 13 projecting downward from the lower surface. The sleepers 20 may be placed on top of the ballast stones B. In this case, if the sleeper pad 10 having the convex portion 13 is provided below the sleeper 20, the convex portion 13 will fit into the gap between the ballast stones B, thereby improving the grip of the sleeper pad 10.

It is preferable that the convex portions 13 are provided in each of the first extending portions 11 . Further, it is preferable that the convex portion 13 is formed to extend along the Y direction, which is the direction in which the first extending portion 11 extends. At this time, a recess 14 is formed between the two protrusions 13, which is recessed toward the contact surface 15 of the sleeper pad 10. The recess 14 is a gap formed by the two protrusions 13 forming both side surfaces in the X direction and the second extending portion 12 on the contact surface 15 side.

Since the convex portion 13 is formed on the first extended portion 11 which has a large spring constant and is difficult to deform, the first extended portion 11 supports the ballast stone B. Moreover, the ballast stone B often has sharp corner portions. By entering the recess 14, the corner portion of the ballast stone B easily comes into contact with the second extension portion 12, which has a small spring constant and is easily deformed. Therefore, the second extending portion 12 easily buffers the impact acting on the sleeper pad 10 from the ballast stones B caused by vibrations of the sleeper 20 or the like. Therefore, the sleeper pad 10 is less likely to be damaged.

It is preferable that the convex portion 13 has a shape in which the width, which is the length in the X direction, increases toward the contact surface 15 side of the sleeper pad 10. That is, it is preferable that the convex portion 13 is formed so that the concave portion 14 has a so-called tapered shape in which the width becomes narrower toward the contact surface 15 side. According to such a shape of the convex part 13, the corner part of the ballast stone B can easily enter the recess part 14, so that the corner part can easily come into contact with the second extended part 12 instead of the first extended part 11. , the effect of reducing damage to the sleeper pad 10 by the convex portions 13 is improved.

The widths of the convex portions 13 and the concave portions 14 may be set as appropriate depending on the size of the ballast stones B in the environment in which the sleeper pad 10 is used. For example, single-grain crushed stone S-60 (No. 2 crushed stone) according to JIS A5001 is used for general railway bed ballast. The size of the railroad bed ballast is approximately 40 mm or more and 60 mm or less in major axis.

Assuming a ballast stone B of such a size, the width of the second extending portion 12 that defines the width of the recess 14 is preferably at least 5 mm or more, more preferably 10 mm or more, and 20 mm or more. It is more preferable that Further, from the viewpoint of stably supporting the sleeper pad 10 on the ballast stone B by the convex portion 13, the width of the second extending portion 12 is preferably 60 mm or less, more preferably 50 mm or less, More preferably, it is 40 mm or less.

The width of the first stretched portion 11 that defines the width of the convex portion 13 is preferably within twice the width of the second stretched portion 12, and more preferably within 1.5 times. In addition, from the viewpoint of durability of the sleeper pad 10, the width of the first stretched portion 11 is preferably 0.5 times or more, more preferably 0.8 times or more, the width of the second stretched portion 12. preferable.

Moreover, the widths of the plurality of first extending portions 11 may all be the same, or at least some of them may be different. For example, the width of the first extending portion 11 may increase toward each outer end in the X direction. According to such a configuration, support of the sleeper pad 10 by the first extending portion 11 can be stabilized. Further, the widths of the plurality of second extending portions 12 may all be the same, or at least some of them may be different.

The thickness, which is the length of the sleeper pad 10 in the Z direction, is not particularly limited, but from the viewpoint of fixing stability of the sleeper 20, it is preferably 20 mm or less, and more preferably 15 mm or less. Further, from the viewpoint of vibration damping performance, the thickness of the sleeper pad 10 is preferably 3 mm or more, and more preferably 5 mm or more.

When the thickness of the sleeper pad 10 is defined as the thickness of the base not including the convex portion 13, the thickness of the sleeper pad 10 is preferably the same as the thickness of the second extension portion 12. Further, since it is preferable that the first stretched portion 11 has the convex portion 13, the thickness of the first stretched portion 11 is greater than the thickness of the second stretched portion 12 by at least the protruding length of the convex portion 13. It is preferable. In order for the convex part 13 to stably support the sleeper pad 10, the protrusion length of the convex part 13 must be set so that at least a part of the ballast stone B can enter the concave part 14, for example, It is preferable that the width is two-thirds or less of the width of the two extending portions 12.

(adjustment of spring constant)
The overall spring constant kt of the sleeper pad 10 may be adjusted by the volume ratio of the first extending section 11 and the second extending section 12. The overall spring constant kt becomes a larger value as the volume ratio of the first stretched part 11 is larger than the volume ratio of the second stretched part 12.

FIG. 4 shows a graph of the results of a simulation of the relationship between the volume ratio of the first stretched portion 11 and the second stretched portion 12 and the overall spring constant kt of the sleeper pad 10. In this simulation, non-foamed EPDM was used as the material for the first stretched section 11, and foamed EPDM was used as the material for the second stretched section 12. Here, the "first member" shown in FIG. 4 is a sample in which the material of the first stretched part 11 is used as a pad alone, and the "second member" is a sample in which the material of the second stretched part 12 is used as a pad alone. It is. Further, two types of commercially available polyurethane pads were used as samples of Reference Example 1 and Reference Example 2, respectively.

First, a compressive load measurement was performed on these samples by sandwiching a 6 mm thick sample between flat plates. Regarding the compressive load curve of each sample obtained by the measurement, the spring constant of each sample was calculated from the range where the slope is linearly stable (the range between the two black circles in each compressive load curve shown in Figure 4). Calculated. The spring constants were 926 kN/mm for the first member, 39 kN/mm for the second member, 140 kN/mm for Reference Example 1, and 80 kN/mm for Reference Example 2.

Next, a compression load curve of the sleeper pad 10 was estimated by simulation, assuming that the material of the first member was used for the first stretched portion 11 and the material of the second member was used for the second stretched portion 12. The compressive load curve obtained by estimation is shown in FIG. 4 as a "synthetic curve." The overall spring constant kt of the sleeper pad 10 was 77 kN/mm, assuming that the first stretched portion 11 was 5% by volume and the second stretched portion 12 was 95% by volume. Further, the overall spring constant kt of the sleeper pad 10 was 141 kN/mm, assuming that the first stretched portion 11 was 14% by volume and the second stretched portion 12 was 86% by volume.

From the above results, it was shown that the larger the volume ratio of the first stretched portions 11 in the sleeper pad 10 is, the larger the overall spring constant kt of the sleeper pad 10 is.

〔Production method〕
The sleeper pad 10 may be manufactured by, for example, integral molding by extrusion. Specifically, the method for manufacturing the sleeper pad 10 includes a plurality of first stretched parts 11 formed of a rubber material or a resin material that extend in the Y direction, and a plurality of first stretched parts 11 that extend in the Y direction and are made of a rubber material or a resin material. The method may include an extrusion step of extruding a plurality of second extending portions 12 made of a rubber material or a resin material having a small spring constant. The rubber material or resin material used to form each of the first stretched portion 11 and the second stretched portion 12 is the same as described in [Structure of sleeper pad] above, and therefore, description thereof will be omitted here.

In the extrusion step, the first stretched parts 11 and the second stretched parts 12 are extruded so that each of the plurality of first stretched parts 11 and each of the plurality of second stretched parts 12 are adjacent to each other in the X direction. It is preferable to integrally mold the material. In addition, the method for manufacturing the sleeper pad 10 includes final molding of the first stretched portion 11 and the second stretched portion 12 integrally formed by an extrusion process using, for example, a continuous vulcanization furnace, a cooling device, a mold, etc. It may further include a step.

In this way, by integrally molding the first stretched portion 11 and the second stretched portion 12 by extrusion, the sleeper pad 10 can be easily manufactured in large quantities in a short time. Moreover, since the shape of the extruded cross section by extrusion molding can be easily changed, the shape of the cross section defined by the X direction and the Z direction of the first stretched part 11 and the second stretched part 12 can be easily changed in design.

Note that the method for manufacturing the sleeper pad 10 is not limited to the above method. The sleeper pad 10 may be manufactured by, for example, a molding method. In this case, for example, the first stretched section 11 may be manufactured in advance, and the obtained first stretched section 11 may be placed in a mold to form the second stretched section 12.

Further, the plurality of first stretched parts 11 and the plurality of second stretched parts 12 are manufactured separately, and the first stretched parts 11 and the second stretched parts 12 are arranged so that they are adjacent to each other in the X direction. Alternatively, they may be manufactured by bonding them together using an adhesive or the like.

[Modified example]
Various modifications of the sleeper pad 10 according to this embodiment are envisioned. As a modified example of the sleeper pad 10, for example, as shown in FIG. 5, there is a sleeper pad 10a that does not have the convex portion 13. In the sleeper pad 10a, the first extending portion 11a and the second extending portion 12 have substantially the same thickness. Therefore, the first extending portion 11a does not have the convex portion 13.

Even in such a sleeper pad 10a, like the sleeper pad 10, the overall spring constant kt is lower than the first spring constant k1 of the first stretched portion 11a, while the durability is the same as that of the first stretched portion 11a. It can be secured to a certain extent.

Further, the sleeper pad 10a without the convex portion 13 can be suitably used as a vibration damping member provided between the sleeper 20 and the rail R. That is, the contact surface 15 of the sleeper pad 10a may be in contact with the upper surface of the sleeper 20.

〔summary〕
A sleeper pad according to aspect 1 of the present invention is a sleeper pad that is provided on the surface of a sleeper to reduce vibrations of the sleeper, wherein the surface of the sleeper pad in contact with the surface of the sleeper is a contact surface, and the contact surface If the directions defining the above are the first direction and the second direction, a plurality of first stretched parts extending in the first direction, and a plurality of first stretched parts extending in the first direction and having a smaller spring constant than the first stretched parts. a second stretching part, each of the plurality of first stretching parts and each of the plurality of second stretching parts being arranged adjacent to each other in the second direction.

A sleeper pad according to an aspect 2 of the present invention is the sleeper pad according to the aspect 1, which has a convex portion projecting downward from the lower surface of the sleeper pad, and the contact surface is in contact with the surface of the sleeper on the lower side of the sleeper. It's okay.

In the sleeper pad according to aspect 3 of the present invention, in aspect 1 or 2, the convex portion may be provided in each of the first extending portions.

In the sleeper pad according to aspect 4 of the present invention, in any one of aspects 1 to 3, the first stretched portion may be made of EPDM (ethylene-propylene-diene copolymer rubber).

In the sleeper pad according to aspect 5 of the present invention, in any one of aspects 1 to 4, the first stretched portion may be made of a non-foaming material, and the material of the second stretched portion may be foamed. .

A method for manufacturing a sleeper pad according to aspect 6 of the present invention is a method for manufacturing a sleeper pad that reduces vibrations of the sleeper by providing the sleeper pad on the surface of the sleeper, wherein the sleeper pad contacts a surface that is in contact with the surface of the sleeper. a plurality of first stretching portions formed of a rubber material or a resin material and extending in the first direction; a plurality of second stretched parts molded from a rubber material or a resin material, the second stretched parts having a spring constant smaller than that of the first stretched parts; The first stretched portion and the second stretched portion are integrally molded by extrusion so that each of the first stretched portions and each of the plurality of second stretched portions are adjacent to each other in the second direction.

[Additional notes]
The present invention is not limited to the embodiments described above, and various modifications can be made within the scope of the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. are also included within the technical scope of the present invention.

10, 10a Sleeper pad 11, 11a First extending portion 12 Second extending portion 13 Convex portion 14 Recessed portion 15 Contact surface 20 Sleeper R Rail B Ballast stone

Claims (6)

A sleeper pad that reduces vibration of the sleeper by being provided on the surface of the sleeper,
When the surface of the sleeper pad in contact with the surface of the sleeper is a contact surface, and the directions defining the contact surface are a first direction and a second direction,
a plurality of first stretching parts extending in the first direction;
a plurality of second stretched parts extending in the first direction and having a smaller spring constant than the first stretched parts;
A sleeper pad, wherein each of the plurality of first extension parts and each of the plurality of second extension parts are arranged adjacent to each other in the second direction. having a convex portion protruding downward from the lower surface of the sleeper pad;
The sleeper pad according to claim 1, wherein the contact surface contacts the surface of the sleeper on the underside of the sleeper. The sleeper pad according to claim 2, wherein the convex portion is provided in each of the first extension portions. The sleeper pad according to claim 1, wherein the first stretched portion is made of EPDM (ethylene-propylene-diene copolymer rubber). The sleeper pad according to any one of claims 1 to 4, wherein the first stretched portion is made of a non-foamable material, and the second stretched portion is made of a foamed material. A method for manufacturing a sleeper pad that reduces vibration of the sleeper by providing it on the surface of the sleeper, the method comprising:
When the surface of the sleeper pad in contact with the surface of the sleeper is a contact surface, and the directions defining the contact surface are a first direction and a second direction,
a plurality of first stretched parts formed of a rubber material or a resin material, stretched in the first direction; and a rubber material or resin material, stretched in the first direction and having a smaller spring constant than the first stretched parts. and an extrusion step of extruding a plurality of second stretched parts formed by
In the extrusion step, the first stretching section and the second stretching section are arranged such that each of the plurality of first stretching sections and each of the plurality of second stretching sections are adjacent to each other in the second direction. A method for manufacturing sleeper pads that is integrally molded by extrusion.

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