Tongue Rail Manufacturing Method
By designing a tongue rail with an inclined second surface and wider top surface based on flange contact angles, the method addresses wear issues, extending the replacement cycle and ensuring safe operation while reducing costs.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- CENTRAL JAPAN RAILWAY COMPANY
- Filing Date
- 2022-08-02
- Publication Date
- 2026-07-07
AI Technical Summary
Wear on tongue rails due to contact with railway vehicle wheels necessitates frequent replacement, which can compromise safety if the shape is altered to extend the replacement cycle.
Designing a tongue rail with a second surface inclined based on the flange contact angle and ensuring a wider top surface while maintaining lateral play space, thereby extending the replacement cycle and reducing stress concentration.
The method extends the replacement cycle of tongue rails, maintains safe operation, and reduces molding costs by optimizing the shape and dimensions of the tongue rail.
Smart Images
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Abstract
Description
Technical Field
[0001] This disclosure relates to a method for manufacturing a tongue rail.
Background Art
[0002] A turnout of a railway vehicle is composed of a main rail and a tongue rail operated by a switch (see Patent Document 1). The tongue rail moves between a position in contact with the main rail and a position away from the main rail as the track is switched.
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0004] Wear occurs on the tongue rail due to contact with the wheels of railway vehicles. Therefore, the tongue rail needs to be replaced at regular intervals. To extend the replacement cycle of the tongue rail, it is conceivable to increase the width of the top of the tongue rail, but an easy change in the shape of the tongue rail affects the safe running of the vehicle.
[0005] One aspect of this disclosure aims to provide a method for manufacturing a tongue rail that can extend the replacement cycle.
Means for Solving the Problems
[0006] One aspect of the present disclosure is a method for manufacturing a tongue rail having a first surface configured to contact the side surface of a basic rail constituting a railway turnout, and a second surface provided on the opposite side of the first surface in the width direction of the basic rail. The method for manufacturing the tongue rail includes a step of determining the shape of the tongue rail. In the determining step, the angle of inclination of the second surface with respect to the horizontal direction is determined based on the angle of inclination of the contact portion of the flange of the railway vehicle's wheel with the tongue rail with respect to the horizontal direction.
[0007] With this configuration, the inclination angle of the second surface of the tongue rail is designed based on the inclination angle of the flange contact area, which allows for a wider top surface of the tongue rail while suppressing wheel overhang on the track. As a result, the replacement cycle of the tongue rail can be extended.
[0008] In one aspect of this disclosure, the determination process may involve setting the width of the top surface of the tongue rail to a size such that the lateral play space of the wheels in the turnout is greater than or equal to the lateral play space of the wheels in the general track connected to the turnout. With such a configuration, the width of the top surface of the tongue rail can be maximized while avoiding any impact on safe operation. It should be noted that, as disclosed in, for example, Japanese Patent No. 2554987, Japanese Patent Publication No. 2007-169997, "Structure and Maintenance of Turnouts" (by Yasuo Sato, 2nd edition, June 10, 2011, pp. 38-41), "Turnouts and EJ" (by Tsuneyoshi Kitakata, August 30, 1973, pp. 84-91), the idea of using lateral play space has not been considered in the design philosophy of tongue rails to date.
[0009] In one aspect of this disclosure, the determining step may result in the second surface being a plane continuous with the top surface of the tongue rail. With such a configuration, the molding cost of the tongue rail can be reduced, and stress concentration at the top of the tongue rail can be suppressed. [Brief explanation of the drawing]
[0010] [Figure 1] Figure 1A is a schematic plan view of the basic rail and tongue rail in the embodiment, and Figure 1B is a schematic side view of the tongue rail in Figure 1A. [Figure 2] Figure 2A is a schematic cross-sectional view along the line IIA-IIA in Figure 1A, and Figure 2B is a schematic partial cross-sectional view near the vertex of Figure 2A. [Figure 3] Figure 3 is a flowchart showing the method for manufacturing the tongue rail in the embodiment. [Figure 4] Figure 4 is a schematic partial cross-sectional view of a hypothetical plane containing the central axis of a railway vehicle's wheel. [Figure 5] Figure 5 is a schematic partial cross-sectional view showing the basic rail, tongue rail, and flange. [Figure 6] Figure 6 is a schematic cross-sectional view showing the lateral displacement of the flange relative to the tongue rail. [Figure 7] Figure 7 is a schematic cross-sectional view showing the lateral displacement of the flange with respect to the opposing base rail. [Figure 8] Figure 8 is a schematic cross-sectional view of the tongue rail in a different embodiment from Figure 2B. [Modes for carrying out the invention]
[0011] Embodiments to which this disclosure applies will be described below with reference to the drawings. [1. First Embodiment] [1-1. Structure] The manufacturing method of the tongue rail in this embodiment is carried out with the aim of obtaining the tongue rail 20 shown in Figures 1A and 1B.
[0012] <Tong Rail> The tongue rail 20 is installed at a turnout in a railway track. A turnout is a structure that branches off a track. The turnout consists of a base rail 10, a tongue rail 20, and a switch (not shown).
[0013] The base rail 10 is a rail fixed at the turnout. In Figure 1A, only one base rail 10 is shown, but the turnout has an opposing base rail that is paired with this base rail 10.
[0014] The tongue rail 20 is a rail movable relative to the base rail 10. In FIG. 1A, only one tongue rail 20 is shown, but the switch has an opposing tongue rail that pairs with this tongue rail 20.
[0015] The tongue rail 20 has a connecting end 20A configured to contact the base rail 10 from the inner side in the rail width direction. The tongue rail 20 is moved by a turnout to a position where the connecting end 20A contacts the base rail 10 and a position where the connecting end 20A is separated from the base rail 10. The height of the tongue rail 20 increases as it moves away from the connecting end 20A.
[0016] As shown in FIG. 2A, the tongue rail 20 has a first surface 21, a second surface 22, and a top surface 23.
[0017] The first surface 21 constitutes the outer side surface of the tongue rail 20 in the rail width direction. The first surface 21 is configured to contact the side surface 11 of the base rail 10. The first surface 21 is a plane inclined so as to face outward in the rail width direction as it goes downward. The side surface 11 of the base rail 10 is an inclined surface provided at the portion of the base rail 10 where the tongue rail 20 contacts. The side surface 11 is a plane parallel to the first surface 21.
[0018] The first surface 21 extends from the inner end of the top surface 23 in the width direction to below the side surface 11 of the base rail 10. The first inclination angle Θ1 of the first surface 21 with respect to the horizontal direction is, for example, about 72°. Note that the first surface 21 does not necessarily have to be inclined with respect to the horizontal direction and may be a vertical plane.
[0019] The second surface 22 constitutes the inner side surface of the tongue rail 20 in the rail width direction. The second surface 22 is provided on the opposite side of the first surface 21 in the width direction of the base rail 10 (that is, in the rail width direction). The second surface 22 is a plane inclined so as to face inward in the rail width direction (that is, away from the base rail 10) as it goes downward.
[0020] The second surface 22 extends from the widthwise inner edge of the top surface 23 to a position below the point through which the lower end of the railway vehicle's wheel (i.e., flange) passes. The second inclination angle Θ2 of the second surface 22 with respect to the horizontal is, for example, between 79° and 81°.
[0021] The top surface 23 constitutes the uppermost surface of the tongue rail 20. The top surface 23 is a plane that is approximately parallel to the horizontal direction.
[0022] The width of the tongue rail 20 (i.e., the horizontal distance between the first surface 21 and the second surface 22) increases downward from the top surface 23. Also, as shown in Figure 1A, the width of the top surface 23 increases as it moves away from the connecting end 20A.
[0023] <How to manufacture tongue rails> The manufacturing method for the tongue rail of this embodiment comprises a determination step S10 and a molding step S20, as shown in Figure 3.
[0024] <Decision process> In this step, the shape of the tongue rail 20 is determined. Specifically, the shapes of the second surface 22 and the top surface 23 included in the cross-sectional shape of the tongue rail 20 are determined.
[0025] In determining the shape of the second surface 22, the shape of the flange 102B of the railway vehicle wheel 101 shown in Figure 4 is used. The wheel 101 comprises an annular rim portion 102 and a disc-shaped plate portion 103 positioned inside the rim portion 102. The rim portion 102 has a tread surface 102A and a flange 102B.
[0026] As shown in Figure 5, the tread surface 102A contacts the uppermost surface of the basic rail 10. The flange 102B contacts the connection point between the top surface 23 and the second surface 22 of the tongue rail 20 (i.e., the inner edge of the top surface 23). The contact portion P of the flange 102B with the tongue rail 20 is worn down by abrasion.
[0027] The third inclination angle φ of the contact portion P with respect to the horizontal direction converges to a certain range due to wear. The third inclination angle φ is the angle with respect to the horizontal direction of the portion of the inner surface of the flange 102B (i.e., the surface facing the rail) that can be considered a straight line in Figure 5. If the inner surface of the flange 102B includes multiple portions that can be considered a straight line, the largest of the angles of these portions with respect to the horizontal direction is taken as the third inclination angle φ. The third inclination angle φ is, for example, 73°.
[0028] In this step, the second inclination angle Θ2 of the second surface 22 with respect to the horizontal is determined based on the inclination angle φ of the contact portion P with respect to the horizontal. That is, the second inclination angle Θ2 is set to be greater than or equal to the maximum value of the third inclination angle φ, while being as close as possible to the maximum value of the third inclination angle φ (i.e., made smaller). Specifically, in this step, the second inclination angle Θ2 of the second surface 22 with respect to the horizontal is set to be between 73° and 81°.
[0029] Furthermore, in this process, the second surface 22 is designed as a plane continuous with the top surface 23. In addition, in this process, the width of the top surface 23 is set to a size such that the lateral play space of the railway vehicle's wheels at the turnout is greater than or equal to the lateral play space of the wheels on the general track connected to the turnout.
[0030] Lateral play is the size of the horizontal gap between the flange and the rail when a railway vehicle is stationary in a straight line. In a turnout, the lateral play is the sum of the lateral displacement D1 of the flange 102B of one wheel 101 of the railway vehicle relative to the tongue rail 20 (as shown in Figure 6) and the lateral displacement D2 of the flange 102B of the other wheel 101 relative to the opposing base rail 30 (as shown in Figure 7). The opposing tongue rail 40 is positioned inside the opposing base rail 30.
[0031] The lateral displacements D1 and D2 can be determined using the contact geometry between the wheel 101 and the rail (see, for example, "Dynamics and Modeling of Railway Vehicles" (Japan Society of Mechanical Engineers, 1st edition, December 1, 2017, pp. 38-47)).
[0032] In general railway tracks, the lateral play is the sum of the lateral displacements of the flanges of each pair of wheels on the left and right sides of a railway vehicle relative to the rails that make up the general railway track. The lateral displacement in general railway tracks can be determined using the same procedure as the lateral displacement in turnouts.
[0033] <Forming process> In this process, the steel material for the tongue rail is formed into the shape determined in the determination step S10 by conventional cutting or other methods. This yields the tongue rail 20.
[0034] [1-2. Effects] According to the embodiments described in detail above, the following effects can be obtained. (1a) By designing the second inclination angle Θ2 of the second surface 22 of the tongue rail 20 based on the third inclination angle φ of the flange contact portion, the width of the top of the tongue rail 20 can be increased while suppressing wheel riding up on the track. As a result, the replacement cycle of the tongue rail 20 can be extended.
[0035] (1b) By making the width of the top surface 23 of the tongue rail 20 such that the lateral play space of the railway vehicle's wheels at the turnout is greater than or equal to the lateral play space of the wheels at the general track connected to the turnout, the width of the top of the tongue rail 20 can be maximized while avoiding any impact on safe operation.
[0036] (1c) By making the second surface 22 a plane continuous with the top surface 23 of the tongue rail 20, the molding cost of the tongue rail 20 can be reduced, and stress concentration at the top of the tongue rail 20 can be suppressed.
[0037] [2. Other Embodiments] While embodiments of this disclosure have been described above, it goes without saying that this disclosure is not limited to the embodiments described above and can take various forms.
[0038] (2a) In the manufacturing method of the tongue rail according to the above embodiment, as shown in Figure 8, a first vertical surface 24 substantially parallel to the vertical direction may be provided between the first surface 21 and the top surface 23 of the tongue rail 20. Alternatively, a second vertical surface 25 substantially parallel to the vertical direction may be provided between the second surface 22 and the top surface 23. That is, the tongue rail 20 may have steps on the inside and / or outside in the rail width direction of the top.
[0039] (2b) The functions of one component in the above embodiment may be distributed among multiple components, or the functions of multiple components may be integrated into one component. Also, some parts of the configuration of the above embodiment may be omitted. Also, at least some parts of the configuration of the above embodiment may be added to, substituted for, or otherwise used in the configuration of other above embodiments. Any aspect of the technical concept specified by the wording of the claims is an embodiment of the present disclosure. [Explanation of symbols]
[0040] 10...Basic rail, 11...Side rail, 20...Tongue rail, 20A...Connecting end, 21...first surface, 22...second surface, 23...top surface, 24...first vertical surface, 25...Second vertical plane, 30...Opposite basic rail, 40...Opposite tongue rail, 101...Wheel, 102...Rim section, 102A...Tread surface, 102B...Flange, 103...Plate section.
Claims
1. A method for manufacturing a tongue rail having a first surface configured to contact the side surface of a basic rail constituting a railway turnout, a second surface provided on the opposite side of the first surface in the width direction of the basic rail, and a top surface provided between the first surface and the second surface, The process includes determining the shape of the tongue rail, In the aforementioned decision-making process, The second surface is a plane, and, A method for manufacturing a tongue rail, wherein the inclination angle of the second surface with respect to the horizontal is determined to be greater than or equal to the inclination angle of the portion of the flange of the railway vehicle's wheel facing the tongue rail that has the largest inclination angle with respect to the horizontal.
2. The method for manufacturing a tongue rail according to claim 1, wherein in the step of determining the above, the width of the top surface of the tongue rail is set to a size such that the lateral play space of the wheel in the turnout is equal to or greater than the lateral play space of the wheel in the general track connected to the turnout.
3. The method for manufacturing a tongue rail according to claim 1 or 2, wherein in the step of determining the above, the second surface is a plane continuous with the top surface of the tongue rail.