Track pad

Abstract

This provides a track pad that maintains compression in the direction of the load until a load of up to 50 kN is applied during a compression deformation test, enabling low compression spring constants of 15 MN / m to 20 MN / m. [Solution] The flat plate-shaped member 12 of the track pad 10 is composed of a flat plate-shaped base portion 16, a plurality of recesses provided on the lower surface 18 of the flat plate-shaped base portion, and a pressure-receiving portion 22 that extends from the bottom surface of the recesses and beyond the lower surface 18. In a compression deformation test, when the pressure-receiving portion 22 is compressed and deformed and engages with the recess wall surface defining the recess, further deformation in the direction of the engaged recess wall surface is prevented, and the compression is sustained.

Description

Technical Field

[0001] The present invention relates to a track pad used in railway tracks.

Background Art

[0002] A track pad has a flat plate-like member made of an elastic material such as rubber or resin, and is installed between a rail support such as a sleeper or a tie plate and a rail, mainly to mitigate (buffer) the impact on the support when a vehicle passes and to suppress noise generation.

[0003] In conventional track pads, in order to obtain the required buffering effect, it is common to adjust the compression spring constant of the track pad by providing a plurality of recesses spaced from each other or a plurality of elongated grooves parallel to each other on both sides or one side of the elastic flat plate-like member (Patent Documents 1, Patent Document 2). That is, this makes it easier to compress the track pad by reducing the pressure receiving area of the load received from the rail supported by the track pad or the sleeper or tie plate supporting the track pad by providing recesses or elongated grooves, that is, to lower the compression spring constant of the track pad to a required value.

[0004] In recent years, with the increase in railway speed, low spring constant track pads with a compression spring constant of 28 MN / m to 30 MN / m have been used, but in places where noise is particularly problematic, those with a spring constant of 15 MN / m to 20 MN / m are being demanded.

[0005] To date, attempts have been made to lower the compression spring constant by increasing the number of grooves and indentations, or by increasing the groove width and the opening area of ​​the indentations, but it has not been possible to obtain the required low spring constant of 15-20 MN / m. Specifically, in order to determine whether a track pad has the required spring constant, a compression deformation test is performed on the track pad. In this test, a load of up to 10 kN is first applied to the track pad under test, and in that state, the gauge scale for measuring the amount of compression of the track pad is set to zero. Then, the load is gradually increased from 10 kN to 50 kN, and the amount of compression is measured to determine whether the required spring constant has been obtained. In this compression deformation test, as mentioned above, track pads with an increased number of grooves or wider grooves buckled before a 50kN load was applied because the elongated pressure-receiving portion between the grooves buckled, preventing the acquisition of the required spring constant (15-20MN / m). Similarly, track pads with an increased number of indentations or larger indentation openings hardened before a 50kN load was applied, resulting in the inability to obtain the required spring constant. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2006-265841 [Patent Document 2] Japanese Patent Publication No. 2019-199744 [Overview of the project] [Problems that the invention aims to solve]

[0007] The present invention aims to provide a track pad that enables the acquisition of low compression spring constants of 15 MN / m to 20 MN / m without buckling or inhibition of compression in the compression deformation test described above. [Means for solving the problem]

[0008] In other words, the present invention is A track pad having a flat plate-shaped member made of an elastic material such as rubber or resin, which is installed between the rail and rail supports such as sleepers or tie plates, The above-mentioned flat plate-shaped member, A flat base portion, Multiple recesses provided on one side of the flat base portion, From the bottom surface of each of these multiple recesses, a pressure-receiving portion extends perpendicularly to the flat base portion, at a distance from the recess wall surface defining the recess, and beyond one of the aforementioned surfaces. The present invention provides a track pad that, when the pressure-receiving portion is compressed and deformed during a compression deformation test and engages with the recessed wall surface defining the recess, prevents further deformation in the direction of the engaged recessed wall surface.

[0009] In this track pad, the portion that is compressed under load during a compression deformation test is made into multiple pressure-receiving parts extending from the recess, and the pressure-receiving area of ​​each pressure-receiving part is made small to facilitate compression due to the load. Furthermore, if the load causes the pressure-receiving part to engage with the recess wall that defines the recess, this engagement prevents further deformation in the direction of the engaged recess wall, thereby enabling continuous compression in the direction of compression due to the load and allowing the required compression spring constant to be obtained.

[0010] As a specific example, the wall surface of the recess can be cylindrical, and the pressure-receiving part can be cylindrical and concentric with the recess.

[0011] The above-mentioned track pad according to the present invention further, A plurality of additional recesses are provided on one surface of the flat base portion, spaced apart from each other along the outer edge of the flat base portion, and the additional recesses also open to the outer side surface of the flat base portion, An additional pressure-receiving portion extending from the bottom surface of the additional recess, spaced apart from the additional recess wall surface defining the additional recess, perpendicular to the flat base portion, and beyond one of the aforementioned surfaces, the additional pressure-receiving portion having an inner surface facing the additional recess wall surface defining the additional recess, and an outer surface flush with the outer peripheral surface of the flat base portion, It has, The above-mentioned additional pressure-receiving part is designed to be compressed and deformed together with the above-mentioned pressure-receiving part by the load applied in the compression deformation test, and when the additional pressure-receiving part engages with the wall surface of the additional recess defining the additional recess during this compression deformation, further deformation in the direction of the engaged additional recess wall surface can be prevented.

[0012] As a specific example, the recess and the additional recess can be made to the same depth from one of the surfaces of the base portion on the flat plate, and the pressure-receiving portion and the additional pressure-receiving portion from the bottom surface of the recess and the additional recess can be made to the same height.

[0013] In another specific example, the recess can be a groove extending transversely across one of the surfaces of the flat base portion, and the pressure-receiving portion can be a long, elongated shape extending parallel to this groove.

[0014] In this other specific example, the cross-section of the recess and the elongated pressure-receiving portion can be made rectangular.

[0015] Hereinafter, embodiments of the track pad according to the present invention will be described based on the attached drawings. [Brief explanation of the drawing]

[0016] [Figure 1] This figure shows a usage configuration in which a track pad according to the first embodiment of the present invention is set between the rail and the tie plate, and only the track pad is shown in a cross-sectional view. [Figure 2] Figure 1 is a perspective view of the orbital pad from the bottom. [Figure 3] Figure 2 is a top view of the track pad, with the cylindrical pressure-receiving section and other components on the underside indicated by dashed lines. [Figure 4] Figure 3 is a front view of the track pad, and includes a cross-section along line AA in Figure 3. [Figure 5] Figure 3 is a side view of the track pad, and includes a cross-section along the BB line in Figure 3. [Figure 6]It is a front cross-sectional view of the track pad in FIG. 3, and the cross-section is a plane along the line A-A in FIG. 3. [Figure 7] The state of the track pad in FIG. 3 when a load of 50 kN is applied in the compression deformation test is shown in the same cross-section as FIG. 6. [Figure 8] It is a perspective view of the track pad according to the second embodiment of the present invention as seen from the lower surface side. [Figure 9] It is a front view of the track pad in FIG. 8. [Figure 10] It is a front view of the track pad showing the state when a load of 50 kN is applied to the track pad in FIG. 8 in the compression deformation test.

Mode for Carrying Out the Invention

[0017] As shown in FIG. 1, the track pad 10 according to the present invention is set between the rail R and the type plate T set on a sleeper (not shown) for holding the rail R, and is mainly used for buffering the vibration transmitted from the rail R to the type plate T when a vehicle passes. Under the track pad 10 is a variable pad P for eliminating the gap between the track pad 10 and the type plate T.

[0018] The track pad 10 includes a flat plate-like member 12 made of an elastic material such as relatively soft rubber or resin, and a sliding material 14 made of hard rubber or resin provided on the upper surface of the flat plate-like member 12 so as to contact the bottom surface of the rail R of the track pad 10 to reduce the influence of dragging accompanying the expansion and contraction of the rail R. The sliding material 14 is provided as needed and is not an essential element of the track pad 10 according to the present invention.

[0019] As clearly shown in Figures 2 to 6, the flat plate-shaped member 12 has a flat plate-shaped base portion 16, a plurality of recesses 20 provided on one surface 18 of the flat plate-shaped base portion 16 (the lower surface facing the tie plate T in the illustrated example), and a cylindrical pressure-receiving portion 22 that extends concentrically from the bottom surface 20a of each of the plurality of recesses 20, spaced apart from the recess wall surface 20b defining the recess 20, perpendicular to the flat plate-shaped base portion 16, and extends beyond the lower surface 18. Furthermore, the track pad 10 according to this embodiment includes a plurality of additional recesses 24 opened in the lower surface 18 of the flat base portion 16, which are provided spaced apart from each other along the outer peripheral edge of the flat base portion 16 and also open to the outer peripheral side surface 32 of the flat base portion 16, and an additional pressure receiving portion 34 that extends from the bottom surface 26 of the additional recess 24 in a direction perpendicular to the flat base portion 16 and beyond the lower surface 18 of the flat base portion 16, and has an inner surface 30 facing the recess wall surface 28 defining the additional recess 24 and an outer surface 36 that is flush with the outer peripheral side surface 32 of the flat base portion 16.

[0020] The track pad 10 according to the present invention enables a compression spring constant that is considerably lower than that of conventional track pads, with a compression spring constant of 15 MN / m to 20 MN / m. To measure this compression spring constant, a compression deformation test is performed. In this compression deformation test, the track pad 10 is set in a testing machine, and the amount of compression is measured by applying a load from the upper and lower surfaces of the track pad 10. First, a load from 0 kN to 10 kN is applied, and in that state, the gauge scale for measuring the amount of compression of the track pad 10 is set to zero. Then, the load is gradually increased up to 50 kN, and by measuring the amount of compression, it is determined whether or not the required compression spring constant has been obtained. In the compression deformation test of the track pad 10, the substantial compression of the track pad 10 occurs in the cylindrical pressure receiving section 22 and the additional pressure receiving section 34. When a final load of 50 kN is applied in the compression deformation test, the design ensures that the compressed cylindrical pressure receiving section 22 and the additional pressure receiving section 34 are compressed to the extent that they almost fill the recesses 20 and 24, respectively, as shown in Figure 7.

[0021] As described in the background technology, simply reducing the pressure-receiving area of ​​pressure-receiving parts such as the cylindrical pressure-receiving part 22 and the additional pressure-receiving part 34 causes buckling to occur when increasing the load from 10kN to 50kN, making it difficult to obtain the required spring constant. In contrast, in the present invention, both the cylindrical pressure-receiving part 22 and the additional pressure-receiving part 34 are formed to extend within the recess 20 and the additional recess 24, respectively. Even if these pressure-receiving parts buckle and bend laterally due to the load, they are supported by the recess wall surface defining the recess 20 or the additional recess 24. As a result, the deformation (compression) of these pressure-receiving parts in the direction of the load is sustained until a load of 50kN is applied, making it possible to obtain the required spring constant.

[0022] The track pad 40 according to the second embodiment shown in Figures 8 to 10 consists of a flat plate-shaped member 42 made of an elastic material such as relatively soft rubber or resin, and a lubricant 44 made of hard rubber or resin provided on the upper surface of the flat plate-shaped member 42 so as to contact the bottom surface of the rail of the track pad 40, and to reduce the effect of drag caused by the expansion and contraction of the rail.

[0023] The flat plate-shaped member 42 has a flat plate-shaped base portion 46, a plurality of groove-shaped recesses 50 provided on one surface 48 of the flat plate-shaped base portion 46 (the lower surface facing the tie plate in the illustrated example) and extending parallel to each other, and an elongated or wall-shaped pressure-receiving portion 52 extending perpendicularly to the flat plate-shaped base portion 46 from the bottom surface 50a of each of the plurality of recesses 50, spaced apart from the recess wall surface 50b defining the recess 50, and extending beyond the lower surface 48. In the illustrated example, pressure-receiving portions 54 are provided along both side edges of the flat plate-shaped base portion 46, parallel to and at the same height as the pressure-receiving portions 52.

[0024] In this track pad 40, during a compression deformation test, the elongated pressure-receiving sections 52 and 54 receive a load and are compressed in the direction of the bottom surface 50a of the recess 50. Even if buckling occurs due to this compression and the section bends laterally, it is supported by the recess wall surface 50b that defines the recess 50. This allows the compression of these pressure-receiving sections in the direction of the load to be sustained until a load of 50kN is applied, thereby making it possible to obtain the required spring constant.

[0025] The embodiments of the track pad according to the present invention have been described above, but the track pad according to the present invention is not limited to these. For example, although the pressure-receiving portion of the track pad in the first embodiment has been described as cylindrical, this cylindrical shape is not limited to a cylinder as shown in the attached drawings, but is a concept that also includes a truncated cone shape that tapers upwards, and various modifications are possible, such as making the pressure-receiving portion have a polygonal cross-section.

[0026] Examples By providing the following specifications for the track pad according to the first embodiment of the present invention described above, the compression spring constant could be set to 15 ± 3 MN / m. Sliding material: Material: EB material Size: 3mm x 140mm x 180mm Flat plate-shaped member: Material: Black vulcanized rubber with SBR as the main component. Flat base section: Size: 10.5mm thick, rectangular with a cross-section of 140mm x 180mm. Recess: Circular cross-section with a diameter of 15 mm, depth of 4.5 mm Additional recess: 12mm x 23mm rectangle, 4.5mm deep Additional recess at the corner: outer edge 12.0525mm x 11.4475mm, Depth 4.0mm Inner dimensions: 8.5mm x 12mm, depth: 4.5mm Pressure-receiving part: Cylindrical shape with a diameter of 10.5 mm and a height of 9.5 mm Additional pressure-receiving section: 8.5mm x 17mm rectangular cross-section, 9.0mm height Additional pressure-receiving area at the corner: Outer edge 20mm x 20.5mm Inner dimensions: 11.5mm x 12.0mm Width (in the inward and outward directions of the track pad) 8.5 mm Height 9.0mm Number and arrangement of recesses: 6 horizontally and 8 vertically in a matrix, for a total of 48. The spacing between the recesses in the lateral direction is 19 mm. The spacing between the recesses in the vertical direction is 19 mm. Number of additional recesses: 3 on each of the opposing lateral sides of the flat base. Five pieces along each of the opposing vertical directions of the flat base section Additional recesses at the corners: One recess at each of the four corners of the flat base. Lateral distance between the recess and the additional recess: 2.9475 mm Vertical distance between the recess and the additional recess: 3.9475 mm The horizontal and vertical spacing between the additional recess and the adjacent additional recess at the corner: 4 mm and 3 mm, respectively. [Explanation of Symbols]

[0027] 10 orbital pads 12 Flat plate-shaped member 14 Sliding material 16 Flat base portion 18 (Lower surface of the flat base) 20 recesses 20a Bottom surface of the recess 20b Recessed wall surface defining the recess 22 Pressure receiving section 24 Additional recess 26 Bottom surface (of the additional recess) 28 Recessed wall surface defining the additional recess 30 (additional pressure receiving section) inner surface 32 (Outer peripheral side of the flat base portion) 34 Additional pressure receiving section 36 (External surface of the additional pressure receiving section) 40 orbital pads 42 Flat plate-shaped member 44 Sliding material 46 Flat base portion 48 (Lower surface of the flat base) 50 recesses (grooves) 50a Bottom surface of the recess 50b Recessed wall surface defining the recess 52, 54 Pressure receiving section

Claims

1. In a track pad having a flat plate-shaped member made of an elastic material such as rubber or resin, which is installed between the rail and rail supports such as sleepers or tie plates, The flat plate-shaped member is A flat base portion, Multiple recesses provided on one side of the flat base portion, A pressure-receiving portion extends from the bottom surface of each of the multiple recesses, at a distance from the recess wall surface defining the recess, perpendicular to the flat base portion, and beyond one of the surfaces, A track pad having such that when the pressure-receiving portion is compressed and deformed during a compression deformation test and engages with the recessed wall surface defining the recess, further deformation in the direction of the engaged recessed wall surface is prevented.

2. The track pad according to claim 1, wherein the wall surface of the recess defining the recess is cylindrical, and the pressure-receiving portion is cylindrical and concentric with the recess.

3. A plurality of additional recesses are provided on one surface of the flat base portion, spaced apart from each other along the outer edge of the flat base portion, and also open to the outer surface of the flat base portion. An additional pressure receiving portion extending from the bottom surface of the additional recess, spaced apart from the additional recess wall surface defining the additional recess, in a direction perpendicular to the flat base portion, and beyond one of its surfaces, having an inner surface facing the additional recess wall surface defining the additional recess, and an outer surface flush with the outer peripheral surface of the flat base portion, It has, The track pad according to claim 1 or 2, wherein the additional pressure receiving portion is designed to be compressed and deformed together with the pressure receiving portion by the load applied in a compression deformation test, and when the additional pressure receiving portion engages with the wall surface of the additional recess defining the additional recess in this compression deformation, further deformation in the direction of the engaged additional recess wall surface is prevented.

4. The track pad according to claim 3, wherein the recess and the additional recess are of the same depth from one surface of the flat base portion, and the height of the pressure receiving portion and the additional pressure receiving portion from the bottom surface of the recess and the additional recess are the same.

5. The track pad according to claim 1, wherein the recess is a groove extending transversely across one surface of the flat base portion, and the pressure-receiving portion is elongated and extends parallel to the groove.

6. The track pad according to claim 5, wherein the cross-section of the recess and the elongated pressure-receiving portion is rectangular.

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