Design method of fixed frog and wheel-rail contact structure and rail transit structure

Abstract

This invention discloses a design method for a fixed frog and wheel-rail contact structure, as well as a rail transit structure, comprising the following steps: S1. Analyzing the load-bearing width of the wheel-rail contact based on the static geometric relationship of the wheel-rail contact; S2. Determining the wheel-rail contact form based on the load-bearing width of the wheel-rail contact; S3. Designing the frog structure based on the determined wheel-rail contact form. This design method proposes the concept of minimum allowable load-bearing width, providing in-depth theoretical support for the design of fixed frog wheel structures, effectively guiding the structural design of fixed frog structures, resulting in fixed frog structures that better meet the needs of actual application environments, reducing the impact of 'harmful spaces' on rail transit, and effectively improving the overall stability and safety of rail transit structures.

Description

Technical Field

[0001] This invention relates to the field of rail transit turnouts, and in particular, to a design method for a fixed frog and wheel-rail contact structure, and a rail transit structure. Background Technology

[0002] Railway turnouts are key equipment for locomotives and rolling stock to enter or cross one track, enabling them to turn or cross tracks. Among them, the fixed frog is one of the core components of railway turnouts.

[0003] Due to their advantages such as simple structure, good integrity, and stable performance, fixed frogs account for 90% of railway turnouts. The structure of a fixed frog is as follows: Figure 1 As shown. Fixed frogs are divided into wing rails and fork center sections based on the running gear. To allow the wheel flanges to pass normally, a certain width must be maintained between the wing rails and the working edges of the fork center, i.e., the flange groove width. The minimum distance between the two wing rails is the frog throat. From the throat to the actual tip of the fork center, there is a section of track gauge line interruption; this section is called the "hazardous space." The "hazardous space" of a fixed frog cannot be eliminated; it is an inherent property of fixed frogs.

[0004] When the wheel travels from the wing rail towards the fork center and passes through the "harmful space" of the fork, it may deviate from its original direction of travel due to the loss of rail guidance. Figure 2 As shown, at best, this can cause the wheel flange to strike the tip of the fork stem, such as... Figure 3 As shown, in severe cases, the wheel flange may enter the groove of the opposite wheel flange, resulting in a derailment accident.

[0005] As the wheel rolls from the wing rail to the center rail via the frog, it gradually leaves the wing rail. Because the wheel tread is a cone, the wheel descends. (Reference) Figures 4 to 7 As the wheel rolls towards the center rail, it gradually returns to its original horizontal position. The same applies in the reverse direction. Therefore, when the wheelset passes through the harmful space of the frog, there is always a downward vertical tendency, affecting the ride smoothness. In severe cases, it can impact the tip of the fork from above, causing damage to the small section of the fork core, and seriously affecting driving safety. Figures 8 to 10 As shown, when the wheel passes through the "hazardous space," the contact point between the wheel and the wing rail gradually moves outward. Due to the conical shape of the wheel tread, the wheel will slowly descend. The wheel's center trajectory will cause a sinking at the "hazardous space," which will affect the ride comfort and the lifespan of the frog. Furthermore, the degree of sinking increases with the increase of the frog angle, and the resulting hazards will gradually increase as well.

[0006] To address the above issues and improve ride smoothness and extend frog life, a common method is to raise the wing rail height from the throat backwards. When the frog angle is less than 45°, refer to... Figure 11When the wheel passes through the "harmful space," it will always contact the wing rail or fork center without falling into the flange groove, allowing for normal tread bearing during turnout crossing. However, as the turnout angle increases, the required wing rail elevation will increase, and when the angle exceeds 45°, refer to... Figure 12 When a wheel passes through a "hazardous space," the wheel-rail contact point shifts outward to the wheel tread but still doesn't contact the fork center. The wheel will first fall into the flange groove and then impact the fork center. This method of passage generates a strong impact and can damage the fork. In this situation, a flange-supported passage method is typically used, i.e., a shallow flange groove design for the fork. The principle of flange-supported passage is to raise the bottom of the flange groove within the "hazardous space," allowing the wheel flange to bear the weight of the vehicle. During this process, the wheel center remains horizontal, resulting in smooth vehicle operation.

[0007] In summary, the current method for determining which turnout crossing method to use in which situation is based on the frog angle. According to domestic experience and recommendations in turnout design manuals, a 45° frog angle is considered the critical angle for the frog wheel-rail contact method. The choice of frog wheel-rail contact crossing method is determined solely by the frog limit angle. However, due to the diversity of wheel treads and rail types, the wheel-rail relationship is extremely complex. The current method lacks theoretical support for designing the frog flange groove depth and cannot effectively guide the structural design of the frog flange groove depth, often requiring modification and adjustment of the final structure. Summary of the Invention

[0008] This invention provides a design method for a fixed frog and wheel-rail contact structure and a rail transit structure, in order to solve the technical problem that existing design methods, which only use the frog angle as the critical angle for structural design, cannot meet the usage requirements.

[0009] The technical solution adopted in this invention is as follows:

[0010] A design method for a fixed frog and wheel-rail contact structure includes the following:

[0011] S1. Analyze the load-bearing width of the wheel-rail contact based on the static geometric relationship of the wheel-rail contact;

[0012] S2. Determine the wheel-rail contact type based on the load-bearing width of the wheel-rail contact;

[0013] S3. Design the frog structure according to the set wheel-rail contact form.

[0014] As a further improvement to the above technical solution, when calculating the load-bearing width of the wheel-rail contact based on the static geometric relationship of the wheel-rail contact, step S1 includes:

[0015] Using the track gauge line as the reference plane, the static geometric relationship of wheel-rail contact is analyzed based on the wheel rim width, lateral flange back distance, maximum flange groove width of the straight rail of the frog, maximum flange groove width of the curved rail of the frog, minimum allowable cross-sectional width of the frog rail, minimum allowable tread width of the wing rail, and the angle of the fixed frog.

[0016] As a further improvement to the above technical solution, when calculating the load-bearing width of the wheel-rail contact based on the static geometric relationship of the wheel-rail contact, the load-bearing width of the wheel-rail contact is analyzed according to the formula.

[0017]

[0018] In the formula, A is the wheel rim width, B is the lateral flange back distance, C is the maximum flange groove width of the straight frog, D is the maximum flange groove width of the curved frog, E is the minimum allowable cross-sectional width of the frog rail, F is the minimum allowable tread width of the wing rail, and β is the fixed frog angle, with a limit of 0 or a positive number.

[0019] As a further improvement to the above technical solution, step S2 includes:

[0020] If the calculated value of the formula is greater than or equal to the limit, the tread bearing method for crossing the turnout shall be adopted.

[0021] If the calculated value of the formula is less than the limit, the flange-bearing wheel-rail contact type shall be adopted.

[0022] As a further improvement to the above technical solution, step S3 includes:

[0023] If the tread bearing method is used for switching, then the wheel flange groove should be designed as a deep groove structure.

[0024] If a flange-bearing wheel-rail contact type is adopted, the flange groove is designed as a shallow groove structure.

[0025] As a further improvement to the above technical solution, if the wheel flange groove is designed as a deep groove structure, the height of the wing rail will be gradually raised from the throat position of the fork to the actual tip position of the fork center to the standard height.

[0026] As a further improvement to the above technical solution, if the wheel flange groove is designed as a shallow groove structure, the bottom of the wheel flange groove from the frog throat position to the actual tip position of the fork core is raised to a preset depth.

[0027] As a further improvement to the above technical solution, the design method also includes: setting guard rails to constrain the wheels on the opposite track at the frog position.

[0028] As a further improvement to the above technical solution, the wheel rim width does not include the chamfer on the rim end face, and the lateral flange back distance is the lateral flange back distance when the flange back wear is at its maximum.

[0029] According to another aspect of the present invention, a rail transit structure is also provided, which applies the design method of the fixed frog and wheel-rail contact structure described above.

[0030] The present invention has the following beneficial effects:

[0031] This design method analyzes the minimum allowable load-bearing width of the wheel-rail contact between a fixed frog and the rail based on the static geometric relationship of wheel-rail contact. The wheel-rail contact form is determined according to this load-bearing width; that is, when the wheel passes through the harmful space of the frog in the normal tread load-bearing form, the minimum allowable load-bearing width of the wheel-rail contact should be guaranteed under the most unfavorable conditions. If this cannot be guaranteed, other contact forms are adopted, and the frog structure is designed based on the selected contact form. Compared with the existing technology that uses a 45° angle as the critical angle for selecting the wheel-rail contact method of the frog according to the guidance of the "Turnout Design Manual," this design method proposes the concept of minimum allowable load-bearing width, providing in-depth theoretical support for the design of the fixed frog wheel structure. This effectively guides the structural design of the fixed frog structure, resulting in a fixed frog structure that better meets the needs of the actual application environment, reducing the impact of the 'harmful space' on rail transit, and effectively improving the overall stability and safety of the rail transit structure.

[0032] In addition to the objectives, features, and advantages described above, the present invention has other objectives, features, and advantages. The invention will now be described in further detail with reference to the accompanying drawings. Attached Figure Description

[0033] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0034] Figure 1 This is a schematic diagram of a fixed frog structure in the prior art;

[0035] Figure 2 This is a schematic diagram of the impact between the wheel flange and the tip of the fork in existing technology;

[0036] Figure 3 This is a schematic diagram of a wheel accidentally entering the groove of the opposite rim in the existing technology;

[0037] Figure 4 This is a schematic diagram of the current technology of advancing to the front of the throat without any measures at the turnout;

[0038] Figure 5 This is a schematic diagram of a turnout entering a "hazardous space" and about to come into contact with the fork core without any measures in the existing technology;

[0039] Figure 6 This is a schematic diagram of the transition from the wing rail to the fork center in the existing technology of a frog without any measures;

[0040] Figure 7 This is a schematic diagram of the travel from the frog to the frog center in the existing technology without any measures;

[0041] Figure 8 This is a schematic diagram of an ideal wheel passing through a fork in the existing technology;

[0042] Figure 9 This is a schematic diagram of a wheel passing through a turnout without any measures in the existing technology;

[0043] Figure 10 This is a schematic diagram of the center motion trajectory of a wheel when passing through a hazardous space in existing technology;

[0044] Figure 11 This is a schematic diagram of existing technology where there are no measures to cross the turnout when the turnout angle is less than 45°;

[0045] Figure 12 This is a schematic diagram of existing technology where there are no measures to cross the turnout when the turnout angle is greater than 45°;

[0046] Figure 13 This is a diagram showing the static geometry of the wheel and rail in a preferred embodiment of the present invention;

[0047] Figure 14 This is a schematic diagram of the frog traveling to the throat under the tread bearing method of a preferred embodiment of the present invention;

[0048] Figure 15 This is a schematic diagram of the fork entering the "harmful space" and about to contact the fork core under the tread bearing method of a preferred embodiment of the present invention;

[0049] Figure 16 This is a schematic diagram of the transition from the wing rail to the fork center in the tread bearing method of a preferred embodiment of the present invention;

[0050] Figure 17 This is a schematic diagram of the fork travel to the fork center under the tread bearing method of a preferred embodiment of the present invention;

[0051] Figure 18 This is a schematic diagram of the guardrail protecting the "harmful space" according to a preferred embodiment of the present invention. Detailed Implementation

[0052] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0053] Reference Figures 13 to 18 A preferred embodiment of the present invention provides a design method for a fixed frog and wheel-rail contact structure, comprising the following:

[0054] S1. Analyze the load-bearing width of the wheel-rail contact based on the static geometric relationship of the wheel-rail contact;

[0055] S2. Determine the wheel-rail contact type based on the load-bearing width of the wheel-rail contact;

[0056] S3. Design the frog structure according to the set wheel-rail contact form.

[0057] Understandably, this design method analyzes the minimum allowable load-bearing width of the wheel-rail contact between the fixed frog and the wheel-rail based on the static geometric relationship of wheel-rail contact. The wheel-rail contact form is determined according to the load-bearing width; that is, when the wheel passes through the harmful space of the frog in the normal tread load-bearing form, the minimum allowable load-bearing width of the wheel-rail contact should be guaranteed under the most unfavorable conditions. If this cannot be guaranteed, other contact forms are adopted, and the frog structure is designed based on the selected contact form. Compared with the existing technology that uses a 45° angle as the critical angle for selecting the wheel-rail contact method of the frog according to the guidance of the "Turnout Design Manual," this design method proposes the concept of minimum allowable load-bearing width, providing in-depth theoretical support for the design of the fixed frog wheel structure. This effectively guides the structural design of the fixed frog structure, resulting in a fixed frog structure that better meets the needs of the actual application environment, reducing the impact of the 'harmful space' on rail transit, and effectively improving the overall stability and safety of the rail transit structure.

[0058] Furthermore, when calculating the load-bearing width of the wheel-rail contact based on the static geometric relationship of the wheel-rail contact, step S1 includes:

[0059] Using the track gauge line as the reference plane, the static geometric relationship of wheel-rail contact is analyzed based on the wheel rim width, lateral flange back distance, maximum flange groove width of the straight rail of the frog, maximum flange groove width of the curved rail of the frog, minimum allowable cross-sectional width of the frog rail, minimum allowable tread width of the wing rail, and fixed frog angle. Using the track gauge line as the reference plane and based on the above parameters, the static geometric relationship of wheel-rail contact is analyzed. Based on this analysis method, it can be determined whether the load-bearing width of the wheel-rail contact meets the usage requirements in the actual application environment.

[0060] In this embodiment, when calculating the load-bearing width of the wheel-rail contact based on the static geometric relationship of the wheel-rail contact, the load-bearing width of the wheel-rail contact is analyzed according to Equation 1.

[0061]

[0062] In the formula, A is the wheel rim width, B is the lateral flange back distance, C is the maximum flange groove width of the straight frog, D is the maximum flange groove width of the curved frog, E is the minimum allowable cross-sectional width of the frog rail, F is the minimum allowable tread width of the wing rail, and β is the fixed frog angle, with a limit of 0 or a positive number.

[0063] It should be understood that this calculation method can intuitively reflect the static relationship between wheel and rail contact at the turnout. The calculation process is simple and applicable to different types of wheel treads and turnout types. The calculated value obtained in the above calculation method is the difference between the actual contact width of the wheel tread and the minimum allowable bearing width. Ensuring that this difference (calculated value) is greater than the limit value means that the bearing width of the wheel-rail contact meets the requirements. Therefore, the limit value must be 0 or a positive number. It should be noted that the limit value is usually taken as 0, that is, the minimum allowable bearing width is met. When considering material properties and other interference factors such as environmental influence, the limit value can be appropriately increased.

[0064] It should be noted that the wheel rim width does not include the chamfer on the rim end face, the lateral flange back distance is the lateral flange back distance when the flange back wear is at its maximum, the minimum allowable cross-sectional width of the center rail can bear the minimum allowable cross-sectional width of the wheel rolling, and the minimum allowable tread width of the wing rail can bear the minimum allowable tread width of the wheel rolling. Thus, the bearing capacity of the bearing width under the most unfavorable conditions is fully considered, and the minimum allowable bearing width is obtained to ensure the safety and rationality of the design.

[0065] Furthermore, step S2 also includes:

[0066] If the calculated value of Equation 1 is greater than or equal to the limit, the tread bearing method for passing through the turnout shall be adopted. That is, if the bearing width of the wheel-rail contact meets the requirements, the conventional tread bearing method for passing through the turnout can ensure driving safety.

[0067] If the calculated value of Equation 1 is less than the limit, the wheel-rail contact form with flange bearing should be adopted. That is, the bearing width of the wheel-rail contact cannot meet the requirements at this time, and the wheel should be carried by the flange bearing method through the frog to ensure driving safety.

[0068] Based on this, step S3 includes:

[0069] If the tread bearing method is used for crossing the turnout, the wheel flange groove is designed as a deep groove structure;

[0070] Specifically, if the wheel flange groove is designed as a deep groove structure, the height of the wing rail will be gradually raised from the throat position of the frog to the actual tip position of the frog center to the standard height, as referenced. Figures 14 to 17 Within the 'hazardous space' range, the height of the wing rail is gradually increased to keep the wheel center trajectory unchanged. After avoiding the small cross section of the fork core, the height is slowly reduced to the normal height, so that the wheel contact point transitions back to the fork core, effectively extending the fork life and improving the ride smoothness. The specific dimensions of the deep groove structure are designed based on the actual wheel rail and fork structure parameters and with reference to existing structural design methods.

[0071] If a flange-loaded wheel-rail contact method is adopted, the flange groove should be designed as a shallow groove structure.

[0072] Specifically, if the flange groove is designed as a shallow groove structure, the bottom of the flange groove from the frog throat to the actual tip of the fork center is raised to a preset depth, as shown in the reference. Figure 12 The bottom of the wheel flange groove is raised within the 'hazardous space' area to allow the wheel flange to bear the weight, keeping the wheel center movement horizontal and ensuring smooth operation; the specific dimensions of the shallow groove structure are designed based on the actual wheel rail and frog structure parameters and with reference to existing structural design methods.

[0073] In some embodiments, the design method further includes: setting guard rails to constrain the wheels on the opposite track at the frog position, referring to... Figure 18 The guard rail structure can guide the wheels to move forward and prevent them from derailing or getting stuck on the fork tip. In this embodiment, since the above-mentioned design method can ensure driving safety, guard rails do not need to be designed in the specific implementation process, thereby effectively reducing costs.

[0074] On the other hand, this embodiment also provides a rail transit structure that applies the above-mentioned design method for a fixed frog and wheel-rail contact structure.

[0075] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A design method for a fixed frog and wheel-rail contact structure, characterized in that, Includes the following: S1. Analyze the load-bearing width of wheel-rail contact based on the static geometric relationship of wheel-rail contact; taking the track gauge line as the reference plane, analyze the static geometric relationship of wheel-rail contact based on the wheel rim width, lateral flange back distance, maximum flange groove width of the straight rail of the frog, maximum flange groove width of the curved rail of the frog, minimum allowable cross-sectional width of the frog rail, minimum allowable tread width of the wing rail, and the angle of the fixed frog; analyze the load-bearing width of wheel-rail contact according to equation (1). （1）； In the formula, A is the wheel rim width, B is the lateral flange back distance, C is the maximum flange groove width of the straight frog, D is the maximum flange groove width of the curved frog, E is the minimum allowable cross-sectional width of the frog rail, F is the minimum allowable tread width of the wing rail, and β is the fixed frog angle, with a limit of 0 or a positive number; S2. The wheel-rail contact form is determined according to the bearing width of the wheel-rail contact; if the calculated value of equation (1) is greater than or equal to the limit, the tread bearing turnout method is adopted; if the calculated value of equation (1) is less than the limit, the flange bearing wheel-rail contact form is adopted. S3. Design the frog structure according to the set wheel-rail contact form; if the tread bearing method is adopted for the frog, the flange groove is designed as a deep groove structure; if the flange bearing wheel-rail contact form is adopted, the flange groove is designed as a shallow groove structure.

2. The design method for the fixed frog and wheel-rail contact structure according to claim 1, characterized in that, If the wheel flange groove is designed as a deep groove structure, the height of the wing rail will be gradually raised from the throat position of the fork to the actual tip position of the fork center to the standard height.

3. The design method for the fixed frog and wheel-rail contact structure according to claim 1, characterized in that, If the wheel flange groove is designed as a shallow groove structure, the bottom of the wheel flange groove from the frog throat position to the actual tip position of the fork core is raised to a preset depth.

4. The design method for the fixed frog and wheel-rail contact structure according to any one of claims 1-3, characterized in that, The design method also includes: setting guard rails to constrain the wheels on the opposite track at the frog position.

5. The design method for the fixed frog and wheel-rail contact structure according to any one of claims 2-3, characterized in that, The wheel rim width does not include the chamfer on the rim end face, and the lateral flange back distance is the lateral flange back distance when the flange back wear is at its maximum.

6. A rail transit structure, characterized in that, The application uses the design method for the fixed frog and wheel-rail contact structure as described in any one of claims 1-5.

Images