JP6345987B2 - Track pad and track pad manufacturing method - Google Patents

Description

  More particularly, the present invention relates to a track pad and a track pad that are interposed between a sleeper top surface or a tie plate installed on a sleeper top surface and a rail bottom surface. Regarding the method.

  2. Description of the Related Art Conventionally, on a railway track, an elastic thin plate-like pad called a track pad is interposed between a sleeper upper surface or a tie plate installed on the sleeper upper surface and a rail bottom surface. This track pad functions as a cushioning material between sleepers or tie plates and rails and protects them by mitigating loads transmitted to track members below rails such as sleepers and track slabs as the vehicle travels. It plays the role of reducing the vibration generated in the orbit and the noise accompanying it.

  The configuration of the track pad is roughly divided into a configuration made of only a rubber material and a configuration in which a steel plate is fixed on the upper surface (track pad with steel plate). In particular, the latter track pad with steel plate has the advantages that it has less friction with the rail, has better durability, and is less likely to be dragged by the rail even when the rail expands or contracts due to cold or warm conditions. It has been adopted for many years as a track pad for high-speed railways, mainly using long rails.

  In the above-mentioned track pad with a steel plate, the rail does not slip easily on the steel plate due to frictional resistance on the top surface of the steel plate due to rust generated on the surface of the steel plate, and the track pad with the steel plate is dragged as the rail expands and contracts. As a result, the original function of the above-described track pad is lost. In addition, the conventional track pad with a steel plate is heavy because the weight of the steel plate is added to the substrate portion, and there is also a problem that the work efficiency of carrying in and mounting is inferior.

  From such a viewpoint, for example, as disclosed in Patent Document 1, a surface layer plate portion formed of super hard rubber instead of a steel plate and a substrate portion formed of hard rubber having a lower hardness are provided. The structure which comprises the surface layer board part shape | molded from a synthetic resin instead of a steel plate, etc. as proposed by patent document 2 is also proposed. These track pads can be reduced in weight compared to the conventional track pads with steel plates as described above, and there is no reduction in frictional resistance caused by rust, so the track pads are dragged along with the expansion and contraction of the rails. Can be prevented.

  By the way, this type of track pad is likely to generate large vibrations and accompanying noise due to the recent increase in the speed of railways, and the slab track requires higher quietness than the ballast track. In order to solve this problem, it is required to make the spring constant of the track pad as low as possible. However, in the conventional orbital pad disclosed in Patent Document 1 or Patent Document 2 described above, a plurality of concave grooves are usually formed on the upper and lower surfaces of the substrate portion formed of a rubber material, or spaces are formed inside. Since the spring constant is adjusted by adjusting the spring constant, the adjustment width of the spring constant is limited in consideration of the shape and material, and the mechanical strength of the substrate portion is reduced by the groove and the space. There was a problem.

JP 2006-265841 A JP 2011-38319 A

  Therefore, the present invention relates to a track pad, which solves the above-described conventional problem, and provides a track pad and a method of manufacturing the track pad that facilitates adjustment of a spring constant while preventing a decrease in mechanical strength. Objective.

  The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described.

That is, in Claim 1, in the track pad interposed between the sleeper upper surface or the tie plate installed on the sleeper upper surface and the rail bottom surface, a thin plate-like substrate portion formed of foamed rubber, and the substrate portion A thin plate-shaped surface layer plate portion formed of a polyamide-based resin having a friction coefficient lower than that of the upper surface of the substrate portion, and between the upper surface of the substrate portion and the lower surface of the surface layer plate portion. A vulcanized adhesive layer formed and vulcanized with the vulcanized adhesive in a state where the substrate portion and the surface layer plate portion are bonded to each other via the vulcanized adhesive, to fix the substrate portion and the surface layer plate portion; It is provided.

In the present invention, the foamed rubber uses EPDM as a raw rubber.

In Claim 3 , in the manufacturing method of the track pad interposed between the sleeper upper surface or the tie plate installed on the sleeper upper surface and the rail bottom surface, a step of obtaining a thin plate-like substrate portion formed from foam rubber; A step of applying a vulcanized adhesive composed of a primer and a top coat to the surface of a thin plate-shaped surface layer plate portion formed from a synthetic resin, and a vulcanized adhesive of the surface layer plate portion is applied to the upper surface of the substrate portion And a step of vulcanizing a vulcanized adhesive to form a vulcanized adhesive layer and fixing the substrate portion and the surface layer plate portion with the surfaces adhered together.

In Claim 4 , what remove | excluded the foaming agent among the foamed rubber compositions used as the raw material of the said board | substrate part on the surface of the said board | substrate part and the surface layer board part to which the said vulcanization adhesive agent was apply | coated is a solvent. And a step of coating each of the unvulcanized rubber glue diluted in (1).

  As an effect of the present invention, the spring constant can be easily adjusted while preventing the mechanical strength from being lowered.

It is the front view which showed the state which inserted the track pad which concerns on one Example of this invention to the tie plate. It is sectional drawing of a track pad. It is sectional drawing which showed typically the process of vulcanizing-bonding a board | substrate part and a surface layer board part.

  Next, modes for carrying out the invention will be described.

  As shown in FIG. 1, the track pad 3 of the present embodiment includes a bottom surface 1a of a rail 1 provided along the length direction of the track in a railway track, and a tie plate 2 installed on an upper surface of a sleeper (not shown). It is used in between. The tie plate 2 includes a base 20 formed in a rectangular shape, a pair of shoulders 21 and 21 integrally disposed so as to protrude substantially vertically upward on the upper surface 20 a of the base 20, and a leaf spring for fixing the rail 1. The base 20 is fixed on sleepers with the bolts 23 so that the width direction of the base 20 is aligned with the length direction of the track.

  The shoulders 21 and 21 are provided so as to extend along the width direction of the base 20 (the front-rear direction in FIG. 1) and to be parallel to each other with a predetermined interval. Between the shoulders 21 and 21 on the upper surface 20a of the base 20, a variable pad 26 which is solid in a rectangular bag shape by resin injection is disposed, and a track pad 3 which will be described later is mounted on the upper surface of the variable pad 26. The rail 1 is fixed on the upper surface of the track pad 3 (the upper surface 31a of the surface layer plate portion 31).

  The leaf springs 22 are disposed at both side positions of the rail 1 placed on the base 20, and are attached to the shoulder 21 with the other end 22b side superimposed on the one end 22a side. The leaf spring 22 is provided with a mounting hole (not shown) at a place where the one end 22a side and the other end 22b are overlapped, and a bolt 24 projecting upward from the shoulder 21 is inserted through the mounting hole. The nut 24 is fastened to the bolt 24 and fixed. In this state, the rail 1 is positioned and fixed to the tie plate 2 by pressing the bottom 1a of the rail 1 in the direction of the track pad 3 from the upper end 22a.

  As shown in FIG. 2, the track pad 3 of the present embodiment is fixed to a thin plate-like substrate portion 30 formed of foamed rubber and an upper surface 30 a of the substrate portion 30, and a friction coefficient of the upper surface 30 a of the substrate portion 30. A thin plate-like surface layer plate portion 31 formed from a synthetic resin having a lower coefficient of friction, and a vulcanized adhesive layer 32 formed between the upper surface 30a of the substrate portion 30 and the lower surface 31b of the surface layer plate portion 31. It will be. The track pad 3 of the present embodiment is formed in a rectangular shape in plan view, and the surface layer plate portion 31 is fixed so as to cover the entire surface along the shape of the upper surface 30 a of the substrate portion 30.

  The substrate portion 30 expresses a function as a cushioning material. In the track pad 3 of this embodiment, the substrate portion 30 is molded from foamed rubber (sponge rubber), specifically, solid rubber, liquid rubber, thermoplastic elastomer. A raw material rubber or the like blended with a predetermined foaming agent is vulcanized and formed as a vulcanized rubber sheet having a porous structure generated by a gas generated by thermal decomposition of the foaming agent.

  Examples of the raw rubber include natural rubber (NR), isoprene rubber (IR), styrene-butadiene rubber (SBR), acrylonitrile-butadiene rubber (NBR), chloroprene rubber (CR), ethylene-propylene rubber (EPM), and ethylene. -Known rubber types such as propylene-diene rubber (EPDM) and silicone rubber (UI) can be used. Among them, EPDM is preferable in that it is excellent in heat resistance, cold resistance, compression / repulsion, and mechanical strength. Used.

When EPDM is used as the raw rubber, one or two or more types of EPDM selected from polymer species having different physical properties such as molecular weight, ethylene content, or iodine value may be used in combination. In particular, two or more types of EPDM having different Mooney viscosities are preferably used in a blended manner in order to improve moldability, and EPDM having a Mooney viscosity ML _{1 + 4} (100 ° C.) of 40 to 60 is more preferable. This is because when ML _{1 + 4} (100 ° C.) is 40 or less, aging properties and compression set deteriorate, and when it is 60 or more, flowability deteriorates.

  Organic foaming agents and inorganic foaming agents are known as foaming agents to be blended with the raw rubber, but organic foaming agents are preferably used in terms of good processing stability and foaming gas amount stability. Examples thereof include azo compound (ADCA), hydrazide compound (OBSH), and nitroso compound (DPT). In particular, in the track pad 3 of this embodiment, the spring constant can be easily adjusted by changing the blending amount of the foaming agent blended into the raw rubber in the substrate portion 30.

  Other compounding agents blended into the raw rubber include fillers, vulcanizing agents, vulcanization accelerators, reinforcing agents, softeners, plasticizers, foaming agents, gelling agents, processing aids, anti-aging agents, etc. Various commonly used compounding agents can be used. The compounding amounts of these compounding agents can be the conventional general compounding amounts as long as they do not contradict the purpose of the present invention.

  Since the upper surface 31 a is in contact with the bottom surface 1 a of the rail 1, the surface layer plate portion 31 is molded from a synthetic resin having a higher surface hardness and a lower friction coefficient on the upper surface 31 a than the upper surface 30 a of the substrate portion 30. As such a synthetic resin, a polycarbonate resin or a polyamide resin, which is a kind of engineering plastic having excellent mechanical strength and enhanced heat resistance, can be used. Among these, polyamide resins (6 nylon, 6, 6 nylon) are preferably used in that they are excellent in impact resistance, friction / wear resistance, oil resistance, and the like.

  In particular, the polyamide resin as a synthetic resin has a friction coefficient (for example, a static friction coefficient of 0.16 and a dynamic friction coefficient of 0.14 for nylon 6) and a steel plate (for example, a static friction coefficient of 0.13 and a dynamic friction coefficient of 0.20 for SUS430). The rail 1 placed on the track pad 3 is slippery because it is lower, and the specific gravity (for example, 1.14 in 6 nylon) is lower than that of the steel plate (for example, 7.75 in SUS430), thereby reducing the weight of the track pad 3. Can be achieved. In addition, the melting temperature is high among the synthetic resins (thermoplastic resins) and does not melt at the vulcanization adhesion temperature (140 to 170 ° C.) described later.

  The vulcanized adhesive layer 32 is formed between the upper surface 30 a of the substrate portion 30 and the lower surface 31 b of the surface layer plate portion 31, and the substrate portion 30 and the surface layer plate portion 31 are fixed via the vulcanized adhesive layer 32. The vulcanized adhesive layer 32 is formed by applying a vulcanized adhesive composed of a primer (primer) and a top coat to the lower surface 31 b of the surface layer plate portion 31, and applying the vulcanized adhesive of the surface layer plate portion 31 to the upper surface 30 a of the substrate portion 30. It is formed by vulcanizing such a vulcanized adhesive in a state where the applied lower surface 31b is bonded.

  As the vulcanized adhesive forming the vulcanized adhesive layer 32, a known two-layer vulcanized adhesive can be used. Specifically, as the primer, Chemlock 200, Chemlock 204, Chemlock 205 (above, Road Far East Co., Ltd.), Metaloc P, Metaloc PH-37, Metaloc PH-50 (above, manufactured by Toyo Chemical Research Co., Ltd.) and the like, and as the overcoat, Chemlock 6108, Chemlock XJ-552 Commercial products such as Chemlock 6215 (above, manufactured by Road Far East), METALOC G-25, METALOC F-112, METALOC F-116 (above, manufactured by Toyo Chemical Laboratories), and the like.

Next, a method for manufacturing the track pad 3 will be described below.
As shown in FIG. 3, the track pad 3 of the present embodiment is a process for obtaining a thin plate-like substrate portion 30 molded from foamed rubber, and the surface (lower surface 31b) of the thin plate-like surface layer plate portion 31 formed from synthetic resin. ) With a step of applying a vulcanized adhesive consisting of a primer and a top coat, and a state where the lower surface 31b of the surface layer plate portion 31 coated with the vulcanized adhesive is brought into contact with the upper surface 30a of the substrate portion 30. A step of forming a vulcanized adhesive layer 32 by vulcanizing the sulfur adhesive and fixing the substrate portion 30 and the surface layer plate portion 31 to each other.

  In the step of molding the substrate portion 30, a foamed rubber composition is prepared by blending a predetermined raw rubber as a main component with various other compounding agents in a predetermined blending amount, and a known method (for example, kneading → vulcanization) → Annealing etc.). Usually, the rubber composition is kneaded using a closed kneader or an open roll, and the vulcanization speed is adjusted by controlling the vulcanization temperature (about 150 to 200 ° C.) and time (about 5 to 20 minutes). While vulcanized. In the vulcanization molding, primary vulcanization and secondary vulcanization may be performed. After vulcanization molding, annealing is performed by leaving it in a temperature-controlled room maintained at about 100 ° C. for about 6 to 58 hours (preferably 8 to 18 hours).

  The surface layer plate portion 31 is formed by molding a predetermined synthetic resin by a known method (such as injection molding).

  In the step of fixing the substrate portion 30 and the surface layer plate portion 31, first, a predetermined primer is applied to the lower surface 31 b of the surface layer plate portion 31 by spraying or the like, and then naturally dried to form the primer layer 33 (thickness of about 5 to 20 μm). Then, a top coat is applied to the surface of the undercoat layer 33 by spraying or the like, and then naturally dried to form a top coat layer 34 (thickness of about 5 to 20 μm) (see FIG. 3A). ). Before applying the primer to the lower surface 31b of the surface layer plate portion 31, in order to improve the adhesion to the surface layer plate portion 31, for example, various cleaning treatments such as plasma treatment, surface roughening, and ultraviolet treatment, polishing You may make it perform a process or a chemical | medical agent process.

  In this embodiment, the foaming agent is removed from the foamed rubber composition used as the material of the substrate portion 30 on the surface of the upper coating layer 34 of the upper surface 30a of the substrate portion 30 and the lower surface 31b of the surface layer plate portion 31. The unvulcanized rubber paste diluted with a solvent such as toluene is applied (tomo glue) to form the unvulcanized rubber layer 35 in advance. By forming the unvulcanized rubber layer 35 in this way, a vulcanization reaction occurs in the unvulcanized rubber layer 35 together with the undercoat layer 33 and the topcoat layer 34 during the vulcanization adhesion described below, Bonding at the bonding interface between the substrate portion 30 and the surface layer plate portion 31 can be made stronger.

  Next, the vulcanized adhesive and the unvulcanized rubber glue of the surface layer plate portion 31 were applied to the upper surface 30a to which the unvulcanized rubber glue of the substrate portion 30 was applied (the unvulcanized rubber layer 35 was formed) ( The lower surface 31b on which the undercoat layer 33, the overcoat layer 34 and the unvulcanized rubber layer 35 are formed is bonded together, and in this state, a predetermined vulcanization temperature (about 140 to 170 ° C.) and time (about 5 to 30). And vulcanized (see FIG. 3B). Eventually, when the vulcanization reaction is completed in the primer layer 33 and the topcoat layer 34 (and the unvulcanized rubber layer 35), a vulcanized adhesive layer 32 is formed at the bonding interface between the substrate portion 30 and the surface layer plate portion 31. Thus, the track pad 3 to which the substrate portion 30 and the surface layer plate portion 31 are fixed through the vulcanized adhesive layer 32 is obtained.

  For example, using EPDM as raw material rubber, a substrate part (static spring constant 28 MN / m) conforming to the railway construction / transportation facility maintenance support organization standard “low spring track pad” is molded, and a polyamide resin (6 nylon) is used as a synthetic resin. ) With a vulcanized adhesive comprising a primer (Chemlock 200: manufactured by Road Far East) and a top coat (Chemlock 6108: manufactured by Road Far East). The sample body (Example 1) is excellent by applying and vulcanizing for 15 minutes at a vulcanization temperature of 160 ° C. in a state where the surface of the surface layer plate portion coated with the vulcanized adhesive is bonded to the upper surface of the substrate portion. Can get to.

  As shown in Table 1, as an evaluation of the adhesion of the vulcanized adhesive layer in the sample body (Example 1), peeling was performed at a tensile rate of 20 mm / min under the conditions of 23 ° C. and 50% RH in accordance with JIS-K6850. When a test (n = 5) was performed and the fracture form after shearing was visually observed, cohesive failure of the cured vulcanized adhesive layer, and the vulcanized adhesive layer and the substrate portion and the surface layer plate portion as the adherend were No interfacial delamination was confirmed, and only substrate destruction of the substrate portion was confirmed.

  On the other hand, as a comparative test, a substrate portion (static spring constant 58.8 MN / m) according to the conventional JIS-E1117 “buffer track pad” is formed, and a stainless steel plate (SUS430: manufactured by JFE Steel Co., Ltd.) is used as a surface layer plate portion. ) Was fixed with an adhesive (Cemedine 575F: manufactured by Cemedine), and a peel test (n = 5) according to JIS-K6850 was performed in the same manner as above. As for the fracture mode after shearing, the base material fracture in the substrate part was not confirmed, the cohesive fracture of the adhesive layer (30%), and the interfacial peeling between the adhesive layer and the surface layer plate part as the adherend (70%) ) Was confirmed.

  As described above, the track pad 3 of the present embodiment is a thin plate formed from foam rubber in the track pad 3 interposed between the tie plate 2 installed on the upper surface of the sleeper and the bottom surface 1a of the rail 1. And a thin plate-like surface layer plate portion 31 that is fixed to the upper surface 30a of the substrate portion 30 and is formed of a synthetic resin having a friction coefficient lower than that of the upper surface 30a of the substrate portion 30. Therefore, adjustment of the spring constant is facilitated while preventing a decrease in mechanical strength.

  That is, the track pad 3 of the present embodiment has the substrate portion 30 made of foamed rubber, so that it does not have the grooves and spaces required to lower the spring constant unlike the conventional track pad. In addition, it is possible to easily adjust the required low spring constant while preventing the mechanical strength of the substrate portion 30 from being lowered. In addition, since the surface is formed of a synthetic resin and has a surface plate portion 31 having a low friction coefficient and high mechanical strength, it can be reduced in weight and rusted compared to a conventional track pad with a steel plate. Since the resulting frictional resistance does not decrease and the rail 1 easily slides on the surface layer plate portion 31, it is possible to prevent the track pad 3 from being dragged along with the expansion and contraction of the rail 1.

  In particular, the track pad 3 of the present embodiment includes a vulcanized adhesive layer 32 formed between the upper surface 30a of the substrate portion 30 and the lower surface 31b of the surface layer plate portion 31, and is thus formed from foam rubber. The substrate portion 30 and the surface layer plate portion molded from the synthetic resin can be firmly fixed using the vulcanized adhesive layer 32 as a bonding interface, and the substrate portion 30 can be deformed by vibration impact or heating / pressing of the surface layer plate portion 31. It is possible to prevent the surface layer plate portion 31 from being peeled off.

In addition, as a structure of the track pad 3, it is not limited to the Example mentioned above, A various change is possible unless it deviates from the objective of this invention.
That is, in the track pad 3 of the embodiment described above, the case where the substrate portion 30 and the surface layer plate portion 31 are formed in a thin plate shape having a rectangular shape in plan view has been described, but the shape of the track pad 3 is not particularly limited, For example, a part of both end portions in the longitudinal direction may be configured to protrude outward and bend downward (in the direction opposite to the surface layer plate portion 31 in the substrate portion 30). Parallel or mesh-like uneven portions may be provided on the surfaces of the portion 30 and the surface layer plate portion 31.

  Moreover, in the track pad 3 of the above-described embodiment, a case where a vulcanized adhesive composed of a primer and a top coat is used as the vulcanized adhesive for forming the vulcanized adhesive layer 32 (two-component coating type) has been described. However, only one vulcanized adhesive may be used (one-component coating type).

DESCRIPTION OF SYMBOLS 3 Track pad 30 Board | substrate part 30a Upper surface 31 Surface layer board part 31a Upper surface 31b Lower surface 32 Vulcanization adhesion layer

Claims (4)

In the track pad interposed between the tie plate installed on the sleeper upper surface or the sleeper upper surface and the rail bottom surface,
A thin plate-like substrate portion molded from foamed rubber;
A thin plate-like surface layer plate portion fixed to the upper surface of the substrate portion and molded from a polyamide-based resin having a friction coefficient lower than that of the upper surface of the substrate portion;
Formed between the upper surface of the substrate portion and the lower surface of the surface layer plate portion, and vulcanized adhesive with the substrate portion and the surface layer plate portion bonded together via a vulcanized adhesive, A vulcanized adhesive layer for fixing the substrate portion and the surface layer plate portion;
A track pad characterized by comprising:   The track pad according to claim 1, wherein the foamed rubber uses EPDM as a raw material rubber. In the manufacturing method of the track pad interposed between the tie plate installed on the sleeper upper surface or the sleeper upper surface and the rail bottom surface,
Obtaining a thin plate-like substrate portion molded from foamed rubber;
Applying a vulcanized adhesive composed of a primer and a top coat to the surface of the thin plate-shaped surface layer molded from a synthetic resin;
A vulcanized adhesive layer is formed by vulcanizing the vulcanized adhesive in a state where the surface of the surface layer plate portion coated with the vulcanized adhesive is bonded to the upper surface of the substrate portion, and the substrate portion and the surface layer plate are formed. Fixing the part,
A track pad manufacturing method, comprising:   The surface of the substrate portion and the surface of the surface layer plate portion coated with the vulcanized adhesive are not added with a foamed rubber composition used as a material for the substrate portion, excluding the blowing agent, diluted with a solvent. 4. The method for manufacturing a track pad according to claim 3, further comprising a step of applying a vulcanized rubber paste.

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