JP4665146B2 - Synthetic sleepers - Google Patents

Description

  The present invention relates to a sleeper for railroad tracks, and more particularly, to a synthetic sleeper in which fiber bundles made of a plurality of reinforcing fibers are laminated and hardened with a base material resin.

  As sleepers for railroad tracks, those made of wood or concrete are widely used. However, wood is inferior in durability against rain and the like, and concrete is excellent in durability, but is heavy and inferior in vibration and sound insulation. Therefore, synthetic sleepers reinforced with fiber bundles of long glass fibers using a hard urethane resin or the like as a base material resin have been commercialized as sleepers to replace wood and concrete. A synthetic sleeper and its manufacturing method are detailed in Patent Document 1.

  The fiber bundle is, for example, a long glass fiber (having a diameter of about 20 μm), which is one of reinforcing fibers, and about 5000 TEX bundled with a binder resin. TEX is the weight per meter of length and the unit is mg / m. 5000 TEX is about 5 g / m. The cross section of the fiber bundle is circular and the outer diameter is about 2 mm. The fiber bundle needs to be uniformly dispersed in the base material resin. If it is not uniform, the strength will be insufficient in the test of pulling out the driven dog peg. In addition, if the fiber bundle such as the corner portion of the sleeper is not spread, it may be cracked or chipped due to insufficient strength.

  Conventionally, as shown in FIG. 9, the fiber bundle 10 is provided with protrusions 11 at predetermined intervals in the longitudinal direction. This protrusion 11 is formed by sandwiching and pressing the fiber bundle 10 between two plate-like pressure bodies. FIG. 10 shows a case where such fiber bundles 10 are stacked. In FIG. 10, when the diameter of the fiber bundle 10 is 2 mm and the thickness of the protruding portion 11 is 1 mm, the width of the protruding portion 11 is about 3 mm, and the protruding amount from the outer diameter of the fiber bundle 10 is about 0.5 mm. Become. Such a shape aims at stacking the fiber bundle 10 densely in the vertical direction because there is no protrusion 11 in the vertical direction.

  As shown in FIG. 10, the interval between the fiber bundles 10 is widened by the protrusions 11, and the interval between the fiber bundles 10 is larger than the diameter of the fiber bundle 10, and the base material resin enters the gap. However, although the protrusion part 11 spreads the fiber bundle 10 and the fiber bundle 10 in the left-right direction, the fiber bundle often contacts each other in the up-down direction, and the base resin surrounds each of the fiber bundles 10. In some cases, the strength is weak.

According to the conventional manufacturing method, since the fiber bundle 10 can be densely stacked, no pressure is applied when the fiber bundle 10 is stacked on a mold and hardened with a base material resin. For example, when the sleeper dimensions as a product are 230 mm wide, 140 mm long, and 2200 mm deep, the dimensions of the mold for manufacturing the sleeper are 230 mm wide, 144 mm long, and 2300 mm deep. Since the fiber bundle is not uniform at both ends in the depth direction, it is cut by 50 mm and discarded. Here, the height (bulkyness) at which the fiber bundle is laminated in the vertical direction (depth direction) of the mold is set to 128 mm. For example, a hard urethane resin as a base material resin contains a foaming agent and expands in the course of curing, so 128 mm becomes exactly 140 mm. However, since the fiber bundle 10 is sparse as much as 12 mm as a whole, the strength is also reduced accordingly.
Japanese Patent Laid-Open No. 2002-21002

  The object of the present invention is (1) a shape in which fiber bundles are stacked so that they can be spaced apart in the vertical and horizontal directions, and (2) the amount of protrusion of the fiber bundle to the lower side depends on the thickness of the protrusion. (3) To provide a synthetic sleeper in which even if the base resin is cured, foamed, and expanded, the fiber bundles are separated from each other and are not sparse and a uniform distribution state is obtained.

  In order to achieve the above object, a synthetic sleeper according to the invention described in claim 1 is a synthetic sleeper in which a fiber bundle made of a plurality of reinforcing fibers is dispersed and the periphery thereof is cured with a base material resin. The fiber bundle is provided with bulged portions that are curved and flattened in the longitudinal direction of the fiber bundle at predetermined intervals, and the fiber bundle has a height higher than the product specification in a mold for manufacturing sleepers. A predetermined amount of a hard urethane liquid that is laminated and contains a foaming agent that is a base material resin is added, and then compressed and molded to the height of the product specification.

  Invention of Claim 2 is invention of Claim 1, Comprising: The upward pressurization by which the convex part of the predetermined | prescribed radius which curves the said fiber bundle to a longitudinal direction extends in the direction orthogonal to the longitudinal direction of the said fiber bundle It is preferable that the bulging portion is formed by a piece and a lower pressure piece having a concave portion corresponding to the convex portion being engaged with each other and pressed.

  According to the synthetic sleeper of claim 1 and the method of manufacturing the same according to the present invention, the bulging portion of the fiber bundle is flattened and thus curved, for example, in the left direction and the right direction outside the outer periphery of the fiber bundle. It can be projected downward, i.e. in three directions. Therefore, unlike the conventional protrusions, the fiber bundles can be arranged separately in the left-right direction and the up-down direction. In addition, the fiber bundle is laminated on the mold for sleeper manufacture to a height higher than the product specification, and after a predetermined amount of base material resin is added, it is compressed to the product specification height. The density in the vertical direction is improved. Bubbles generated by the foaming agent contained in the base resin are also suppressed to a small shape by pressure, so that the synthetic sleeper can be made stronger.

  According to the second aspect of the present invention, the amount of protrusion that protrudes downward from the outer periphery of the fiber bundle can be determined by the accuracy of the mold of the lower pressure piece, not the thickness of the bulging portion. That is, the protrusion amount can be determined by the depth of the concave portion of the lower pressure piece. Therefore, the number of fiber bundles to be laminated for obtaining a predetermined bulkiness can be accurately determined.

  Hereinafter, a synthetic sleeper according to the present invention will be described with reference to the drawings.

  FIG. 1 is a perspective view of a fiber bundle used in a synthetic sleeper according to the present invention. As shown in FIG. 1, the fiber bundle 10 (in this example, the diameter is about 2 mm) is provided with bulging portions 20 at predetermined intervals (10 to 50 cm) in the longitudinal direction. The bulging portion 20 is curved in the longitudinal direction of the fiber bundle 10. 2 is a cross-sectional view of the AA cross section of FIG. 1 as viewed from the Z direction (longitudinal direction). The bulging portion 20 has a cross-sectional portion with oblique lines that is flattened. The bulging portion 20 protrudes left and right as well as the lower side. The downward projecting amount t can be formed to an accurate value by the depth of the concave portion of the pressure piece. The left and right protrusion amounts are slightly larger than the lower protrusion amount. The bulging portion 20 is obtained by heating and pressing the shape of the original fiber bundle 10 to deform it. The size of the protruding amount determines the distance between the adjacent fiber bundles 10. In particular, the lower protrusion amount t determines the bulkiness when the fiber bundle 10 is placed in a mold. Assuming that a certain amount of fiber bundle 10 needs to be put into the mold, if the product has a height of 140 mm and t = 0.2 mm, the bulk becomes 148 mm. If the protrusion amount t is increased, the bulkiness increases and the mold becomes larger. Therefore, the protrusion amount is preferably 0.2 mm or more and 1 mm or less for cost effectiveness.

  FIG. 3 is a side view showing a state in which the fiber bundles of FIG. 1 are stacked. It is the figure which looked at the fiber bundle 10 of FIG. 1 from the longitudinal direction (it shows by Z of FIG. 1). It can be seen that the fiber bundle 10 is spaced apart in both the left and right directions and the up and down direction. Here, hard urethane liquid 21 was used as the base material resin. The charged hard urethane liquid 21 enters the gap between the fiber bundles 10 and is cured over 0.5 to 2.0 hours. As shown in the drawing circle, the fiber bundle 10 is obtained by bundling a large number of long glass fibers 19 with a binder resin.

  FIG. 4 is a perspective view of the upper pressure piece and the lower pressure piece. The swelled portion 20 is formed by heating and pressing the fiber bundle 10 at about 165 ° C. In the fiber bundle 10, the convex portion 14 of the upper pressurizing piece 12 is arranged in a direction orthogonal to the longitudinal direction of the fiber bundle 10. The lower pressurizing piece 13 is provided with a concave portion 15 at a position corresponding to the convex portion 14. An open mold is preferable because the fiber bundle containing the unsaturated polyester liquid is compressed. FIG. 5 is a cross-sectional view of the BB cross section of FIG. 4 as viewed from the Y direction. A convex portion 14 is provided at the center of the upper pressurizing piece 12, and a concave portion 15 is provided on the lower pressurizing piece 13 so as to be engaged therewith. The convex portion 14 has an R (radius) of 15 mm and a height of 3 mm. This R (radius) determines the degree of curvature of the bulging portion 20. The width of the recess 15 is 20 mm and the depth is 3 mm. The depth of the recess 15 determines the size of the protrusion amount t. 6 is a cross-sectional view of the CC cross section of FIG. 4 as viewed from the X direction. The upper part of the fiber bundle 10 is pressed and stretched downward.

  FIG. 7 is an external view of a mold of a synthetic sleeper. The fiber bundle 10 shown in FIG. 1 is laminated on the mold 18 and dropped and pressed by the lid 17. For example, when the sleeper dimensions as a product are 230 mm wide, 140 mm long, and 2200 mm deep, the inner dimensions of the mold 18 can be, for example, 230 mm wide, 164 mm long, and 2250 mm deep. In this case, the higher the vertical die size, the higher the fiber bundle can be made bulkier than the product specification height, and the degree of dispersion of the fiber bundle can be improved. Do not fit. The height of the mold 18 is preferably 160 to 180 mm with respect to the product thickness of 140 mm.

  FIG. 8 is a view showing a state in which fiber bundles are stacked on the mold shown in FIG. The height L3 is 140 mm, which is the product specification of the synthetic sleeper. The fiber bundles 10 are laminated to be equal to the height L3, or the height L4 at which the fiber bundles 10 are laminated to the maximum, in this case, up to 148 mm. The height L5 is the height 164 mm of the mold 18. Next, a predetermined amount of the hard urethane liquid 21 is charged. The hard urethane liquid 21 has a permeation speed. Finally, the hard urethane liquid 21 is compressed by the drop lid 17 when it reaches the height L3 of 140 mm. When the liquid rises higher than the thickness of the product specification, it is crushed with a drop lid. That is, the foaming agent of the hard urethane liquid 21 expands in the process of curing, but does not exceed the product specification height L3. Thereby, the fiber bundle 10 does not flow even if the hard urethane liquid 21 is foamed, and when it is laminated up to L4, it is compressed from L4 to L3.

  The curing time when a fiber bundle provided with a conventional plate-like protrusion was laminated and when a fiber bundle provided with a bulge was laminated were compared. As the mold, a 230 × 140 × 2200 mm sleeper was used, both of which were charged with a predetermined amount of fiber bundle and a predetermined amount of hard urethane liquid. Table 1 is a comparison of curing times. Whether it was cured or not was judged by whether there was no “crack” or “swell” immediately after demolding. According to this, the curing time is improved by 33% from 1.5 h to 1.0 h. This is because the hard urethane liquid did not lumps but penetrated evenly between the fiber bundles.

  Next, how to make a conventional synthetic sleeper, 2637 fiber bundles with plate-like protrusions are stacked, and when a predetermined amount of hard urethane liquid is applied and cured without applying pressure, a bulge is provided The obtained fiber bundles of 2,637 were laminated, a predetermined amount of hard urethane liquid was added, and the density and dispersibility were compared when cured by compression. The density (g / cc) of the obtained synthetic sleepers was 0.79 for the prior art and 0.78 for the present invention. The section of 50 mm from the end of the synthetic sleeper is divided into 3 parts vertically (upper layer, middle layer, lower layer), and each side part is divided into 4 parts (1-4, 5-8, 9-12). The number of bundles was compared. Table 2 compares the number of fiber bundles. The total number of fibers is less than 2637 because the upper and lower surfaces are cut for finishing.

  Conventional synthetic sleepers have a larger number of fiber bundles in the upper layer of the synthetic sleeper, and the difference from the lower layer is also greater. This is because the fiber bundle is lifted to the upper layer in the foaming process of the hard urethane of the fiber bundle. In the present invention, the fiber bundles are not biased toward the upper layer, and there are few variations in the number of fiber bundles in the upper layer, middle layer, and lower layer. This is because it is compressed from above by the drop lid at the clamping stage. This restrains the fiber bundle and prevents it from being pushed up to the upper layer during the foaming process. Note that the fiber bundles may be evenly distributed at both ends of the sleeper by pressing the drop lid, and both ends may be cut by 25 mm.

  Table 3 compares the physical properties of the synthetic sleepers created in Table 2. “Material quality” and “product quality” are tests with different sample sizes.

  According to Table 3, since the test was performed with the same number of fiber bundles, there was not much change in the quality of the material. In terms of product quality, the values that are affected by the dispersibility of the fiber bundle, “bending strength”, “screw pullout strength”, and “dognail pullout strength” are all superior values. I understand that.

  Since the present invention is one of fiber reinforced plastic (FRP) products, it can also be applied to suspension bridges other than those for railway tracks.

It is a perspective view of the fiber bundle used for the synthetic sleeper by this invention. Example 1 It is sectional drawing which looked at the AA cross section of FIG. 1 from the Z direction. Example 1 It is a side view which shows the state by which the fiber bundle of FIG. 1 was laminated | stacked. Example 1 It is a perspective view of the upper pressurization piece and the lower pressurization piece by the present invention. Example 1 It is sectional drawing which looked at the BB cross section of FIG. 4 from the Y direction. Example 1 It is sectional drawing which looked at CC cross section of FIG. 4 from the X direction. Example 1 It is an external view of the metal mold | die of a synthetic sleeper. Example 1 It is a figure which shows the state by which the fiber bundle was laminated | stacked on the metal mold | die of FIG. Example 1 It is a perspective view of the conventional fiber bundle. It is a side view which shows the state by which the fiber bundle of FIG. 9 was laminated | stacked.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Fiber bundle 11 Protrusion part 12 Upper pressurization piece 13 Lower pressurization piece 14 Convex part 15 Concave part 17 Dropping lid 18 Mold of sleeper 19 Reinforced long fiber 20 Expansion part 21 Hard urethane liquid L3 Height of sleeper product specification L4 Fiber Maximum height at which the bundles are stacked L5 Mold height t Projection amount from the outer periphery of the fiber bundle

Claims (2)

  A synthetic sleeper in which a fiber bundle made of a plurality of reinforcing fibers is dispersed and the periphery thereof is cured with a base resin, and the fiber bundle is curved in the longitudinal direction of the fiber bundle and is flattened into a flat shape. Bulging portions are provided at predetermined intervals, and the fiber bundle is laminated on a mold for manufacturing sleepers at a height higher than the product specification, and a predetermined amount of hard urethane liquid containing a foaming agent as a base resin A synthetic sleeper characterized by being molded after being compressed to the height of the product specification. A convex portion having a predetermined radius that curves the fiber bundle in the longitudinal direction, an upper pressure piece extending in a direction perpendicular to the longitudinal direction of the fiber bundle, and a lower pressure piece having a concave portion corresponding to the convex portion, The synthetic sleeper according to claim 1, wherein the bulging portion is formed by being engaged with each other and pressed.

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