RU2531994C2 - Back strap for rail joints - Google Patents

Abstract

FIELD: transport.

SUBSTANCE: back strap comprises bed with flat bearing surface in contact with rail base and shaped inner bearing surface in contact with sleeper. Recess is made at strap inner bearing surface to receive cylindrical and rectangular ledges with rounded ends. Cylindrical ledges are arranged at recess periphery on the side of ledges while rectangular ledges are located in symmetry about strap axes and uniformly over recess area.

EFFECT: higher reliability at whatever railway lines.

8 cl, 10 dwg

Description

The invention relates to structural elements of the upper structure of the railway track.

The service characteristics and reliable operation of rail fastenings on a reinforced concrete sub-rail base largely depend on the shock absorbers used in their design (under-rail and head-mounted gaskets). In certain types of fastenings, both rail and padding gaskets are used simultaneously (for example, KB fastening), but fasteners that use only rail mounting (hereinafter gasket) are used more and more widely. Such bonds include, for example, bonds: reinforced concrete, ARS, ZhB-65, W-30, SB-3.

Regardless of the type of bonding, the role of the gaskets is extremely high in ensuring the performance of the bonding. Their main functional purpose is to ensure the stability of the rail track characteristics between scheduled repairs. In addition, gaskets on railway sleepers create resistance to rail displacement, provide electrical insulation and reduce dynamic loads. The performance of the gaskets must be ensured in the temperature range from minus 60 ° C to 60 ° C. Most elastomeric polymeric materials in this temperature range undergo structural (relaxation) changes that affect the performance of the material and the gasket as a whole. Therefore, to ensure the functional suitability of the gaskets, it is necessary to carefully approach the choice of the material from which they are made and their design. This is of particular importance in the transition from conventional to loaded high-speed railways (train speeds of at least 160 km / h), on which dynamic loads during train movement increase significantly.

Known gasket designs are designed for use mainly on low and medium speed tracks and do not take into account the specifics of the rail-sleeper pairing operation for loaded high-speed tracks (1). On figa and on figb shows gaskets with two flat surfaces (2). The design of the gasket in Fig. 1a is designed specifically for installation under the sole of the rail P50. Its distinctive feature is the presence of peripheral collars. Figure 1b shows the design of the gasket under the rail fastening SB-3, characterized by the presence on the opposite ends of the technological recesses (3) (Figure 1b). The main disadvantage of both gaskets is the constant stiffness, regardless of the magnitude of the applied load. Gaskets have insufficient elasticity (damping ability) and are not able to significantly reduce the effect of dynamic loads during high-speed movement (especially at low operating temperatures, when the rigidity of the gasket material increases).

Figure 2 shows the design of the shock-absorbing pad described in (4). A distinctive feature of its design is the presence of longitudinal riffles made on both supporting surfaces. The disadvantages of this design are as follows. The design of the corrugations does not contribute to the elastic restoration of the protrusions during their deformation. In addition, when the strip is deformed by a thickness of 1.5-2 mm, the corrugated walls touch (collapse), which leads to a sharp increase in its rigidity. The performance of through-flutes determines the possibility of water entering the contact zone of the gasket-rail base, which negatively affects the value of the coefficient of friction of the gasket on the rail; when water freezes, the elasticity of the gasket changes and its destruction can occur.

The closest analogue of the invention (prototype) is the design of the gasket under the sole of the rail P65, presented in Figure 3 (5). The gasket contains a base with a flat supporting surface in contact with the rail base, a relief inner surface in contact with the railroad tie, two collars for covering a metal headboard, and the inner relief surface is formed by cylindrical recesses located symmetrically relative to the axes of the strip.

The disadvantage of this design is the difference in the stress state of the gasket material at different points of its cross section and the area of the supporting part during cyclic deformation. This is the cause of the nucleation and development of defects in the volume of the gasket material and its premature failure. In addition, this design does not provide a smooth increase in resistance to deformation of the strip with increasing levels of its mechanical loading. The design of the jumpers of the recesses does not contribute to the elastic recovery of the material during cyclic deformation (the stability of the size of the strip over the thickness is not ensured). The foregoing determines the low operational reliability of this design when applied on high-speed railways.

The objective of the invention is to increase the operational reliability of the rail track during its operation in the design of fasteners both on lines with mixed traffic, including heavy, as well as on high-speed and high-speed routes.

The solution to this problem is achieved by the fact that in a rail track containing a base with a flat supporting surface in contact with the rail base, a relief internal supporting surface in contact with the sleeper, two shoulders for covering a metal filling pad, according to the invention, a recess is made on the internal supporting surface of the strip in which the protrusions of a cylindrical and rectangular with rounded ends of the forms are located, and the cylindrical protrusions are located on the periphery of the recess Niya by clamps and rectangular - symmetrically with respect to the gasket axis and uniformly over the recess area.

An additional improvement in the operational reliability of the rail track is achieved by the fact that:

- the height of the protrusions is taken equal to the depth of the recess;

- the distance between the protrusions, as well as between the protrusions and the shoulders of the recess has a value not less than the height of the protrusions;

- the interface zone shoulder-plane, protrusion (depression) -plane made in the form of a smooth curve;

- the gasket is made of thermoplastic elastomer;

- the gasket material has a glass transition temperature not higher than -60 ° C, and its Shore A hardness in the temperature range from -60 ° C to 60 ° C is in the range of 80-93 conventional units;

- the gasket is made by injection molding;

- the gasket is made of a composite material based on polyester thermoplastic elastomer.

Examples of gasket design options are shown in FIGS. 4-7. On figa, figb presents a design option gaskets in accordance with claim 1 of the claims. A feature of this design is that the cylindrical and rectangular protrusions are made protruding relative to the inner supporting surface of the gasket. Moreover, the protrusions may have unequal heights. Such a design of the protrusions allows you to smoothly increase the resistance to their deformation as the level of dynamic mechanical load acting on them increases until the height of the protrusions becomes equal to the depth of the recess on the inner supporting surface of the gasket. After that, a sharp decrease in the deformation ability of the gasket will occur due to a significant increase in the area of the supporting surface. On figa presents a variant of the design of the gasket with two peripheral collars, and on figb without collars with technological recesses on opposite ends.

When performing the gasket according to claim 2 of the claims (Fig. 5a, Fig. 5b), its elastic-deformation properties, unlike the gaskets shown in Fig. 4a and Fig. 4b, are not subject to sudden changes during fluctuations of the dynamic mechanical load acting on gasket.

In a variant of the rail track (b≥h) described in claim 3 of the claims (FIG. 6), the distance (b) between the protrusions, as well as between the protrusions and the shoulders of the recess, is regulated. If these distances are not less than the height of the protrusions (h), then the likelihood of the side surfaces of the protrusions touching each other, as well as the collars of the recess during deformation of the gasket during train movement, is eliminated. This ensures a smooth change in the elastic-deformation properties of the gasket with increasing dynamic load.

The implementation of the interface zones burt-plane, protrusion (depression) -plane in the form of a smooth curve (paragraph 4 of the claims, Fig.7) eliminates the formation of stress concentrators in these areas and premature failure of the gasket. Such a design of gaskets is particularly preferred for use on high-speed routes operating at low ambient temperatures, causing an increase in the modulus of elasticity of the gasket material and a decrease in its deformability.

The implementation of rail underlay made of thermoplastic elastomer (claim 5 of the claims) helps to reduce energy consumption during its production and provides a wide selection of base materials for producing parts.

According to claim 6, for the manufacture of gaskets, a material is used that has a mechanical glass transition temperature not higher than -60 ° C, and a change in its hardness in the temperature range from -60 ° C to 60 ° C is 80-93 conv. units Shore (scale A). Subject to these conditions, the gasket provides the required stiffness of the bond and a set of other operational requirements in the field of both extremely low (-60 ° C) and high (60 ° C) temperatures.

The use of thermoplastic elastomer for the manufacture of rail rails determines the necessity of using the injection molding method for its manufacture (paragraph 7 of the claims). This ensures high performance of the manufacturing process of the gasket, which helps to reduce its cost.

In accordance with paragraph 8 of the claims, the gasket is made of polyester thermoplastic elastomer. Polyester thermoplastic elastomers are block copolymers of polybutylene terephthalate (hard block) and polytetramethylene oxide (flexible block). An important advantage of this type of thermoplastic elastomers is the ability to control their structure, mechanical and elastic-elastic characteristics by changing the ratio of flexible and rigid blocks in the structure of macromolecules, as well as their molecular weight. These materials are weatherproof, resistant to oil products and vibration resistant.

The combination of distinctive features indicated in the claims allows to realize a previously unknown technical effect, which consists in providing the required elastic-deformation characteristics of the gaskets, depending on the degree of influence of dynamic loads on them. The proposed technical solution provides not only an improvement in the elastic-deformation properties of the gaskets due to the original design, but also ensures fast elastic restoration of the supporting surface elements during their cyclic deformation in a wide temperature range. The claimed technical solution is new and is not a direct consequence of the known technical solutions in the field of structures of fastenings of the upper structure of the railway track.

Thus, the invention is technically easy to implement, and its practical application allows us to solve the problems associated with increasing the operational reliability of rail fastenings when using them both in high-speed and high-speed traffic, and on lines with mixed traffic, including heavy. The invention is recommended to be used, first of all, for the manufacture of rail rail gaskets KB 65.

Information sources

1. A.A. Letkova. Gaskets for fasteners. Way and track facilities. 2007, No. 5. S.15-18.

2. An album of drawings of the upper structure of the railway track. - M .: Transport. 1990. Drawing 94.

3. TU "Laying of rail fastening SB-3", TU BY 400022824.001-2006.

4. An album of drawings of the upper structure of the railway track. - M .: Transport. 1990. Drawing 105.

5. Album of drawings of the upper structure of the railway track. - M .: Transport. 1990. Drawing 99 - prototype.

Claims (8)

1. Rail underlay for rail fasteners, comprising a base with a flat supporting surface in contact with the rail base, a relief internal supporting surface in contact with the sleeper, characterized in that a recess is made on the internal supporting surface in which protrusions are cylindrical and rectangular with rounded ends forms, and the protrusions of a cylindrical shape are located on the periphery of the recess, and the protrusions of a rectangular shape - uniformly over the area of the recess. 2. The gasket according to claim 1, characterized in that the height of the protrusions is equal to the depth of the recess. 3. The gasket according to claim 1 or 2, characterized in that the distance between the protrusions, as well as between the protrusions and the shoulders of the recess is not less than the height of the protrusions. 4. The gasket according to claim 1, characterized in that the collar mating zone is a plane, a protrusion (recess) - the plane is made in the form of a smooth curve. 5. The gasket according to claim 1, characterized in that it is made of thermoplastic elastomer. 6. The gasket according to claim 1, characterized in that it is made of a material having a glass transition temperature not higher than -60 ° C, and its shore hardness A at a temperature of from -60 ° C to 60 ° C is 80-93 cu . 7. The gasket according to claim 1, characterized in that it is made by injection molding. 8. The gasket according to claim 1, characterized in that it is made of a composite material based on polyester thermoplastic elastomer.

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