Prediction method and application of passive steel rail polishing process

Abstract

The invention provides a prediction method and application of a passive steel rail polishing process, and relates to the technical field of rail traffic and steel rail polishing. Polishing amount distribution of different positions under the abscissa of a steel rail head is predicted by combining polishing processes of a field grinding wheel and a steel rail at different acting positions; and then pre-judgment of the polishing process is achieved, polishing process parameters are adjusted in time, and implementation of the passive polishing process and implementation of the polishing target are achieved. Based on the conformal contact mapping relation between the circumferential surfaces of the steel rails of different rail types and the grinding wheels, a grinding process parameter library of a single grinding wheel is obtained, a design basis of a passive grinding process is provided, a process design method is provided for diversified combination of processes of rapid grinding operation, and the blank of domestic related process methods is filled.

Description

Technical Field

[0001] The present invention relates to the technical fields of rail transit and rail grinding, and in particular to a prediction method and application of a passive rail grinding process. Background Art

[0002] With the rapid development of high-speed railways in China, under the action of wear and rolling contact of rails, problems such as rail surface fatigue and smoothness of high-speed railways have begun to appear continuously, which in turn cause damage to track structure components, deterioration of train operation quality, abnormal noise, and increases in maintenance cycle and cost of railway maintenance. Preventive rail grinding work has received increasing attention.

[0003] Rapid rail grinding refers to passive grinding carried out by a rapid rail grinding vehicle. Through the implementation of rapid grinding in small amounts and multiple passes, rail surface damage and defects can be eliminated or reduced, the smoothness of the rail surface can be improved, the generation and development of rail surface diseases such as contact fatigue and corrugation can be prevented or slowed down, the wheel-rail matching relationship can be improved, and the service life of the rail can be extended. Rapid grinding is mainly used for track grinding. In pre-grinding, preventive grinding and repair grinding strategies, grinding operations can be carried out using rapid grinding technology according to requirements. At present, domestic rapid rail grinding mainly adopts a preventive grinding strategy that prevents diseases by removing the shallow-layer material of the rail surface. Rapid rail grinding uses passive grinding of a grinding wheel and a rail. The circumferential surface of the grinding wheel contacts the rail top surface at a certain angle, and the grinding wheel is driven to rotate passively to cut the rail by the traction of a locomotive using the bearing of the grinding wheel itself. The rolling of the grinding stone under the action of friction (driving the rotation of the grinding stone and automatically updating the position of the contact area between the grinding stone and the rail); the sliding caused by the difference in linear velocity between the grinding stone and the rail (realizing the removal of materials). The rapid rail grinding vehicle is equipped with multiple grinding units, and the top surface of the rail is covered and ground through the combination of grinding stones of different grinding units and the rail.

[0004] At present, after rail operators adjust the working positions of the grinding wheels of individual working units with respect to the rail, they combine the grinding processes of different grinding units of the rapid grinding vehicle based on experience. Whether the single-pass grinding process is correct and the final overall grinding process can only be judged based on experience. When multiple passes of grinding are carried out, the cutting amount of the grinding stone on the rail is relatively large. If the rail grinding curve cannot be predicted, it is difficult to control the grinding quality, resulting in a poor wheel-rail contact relationship, affecting the service life of the rail and the running stability of the train. When formulating a passive grinding process, it is difficult to judge in advance the conformal action mode between the grinding stone and the rail, and there is a lack of data on the process mode library of individual grinding stones for different rail profiles. The grinding process is often limited to preventive grinding in small amounts and multiple passes, and can only achieve polishing treatment of the rail surface. It is difficult to scientifically and reasonably formulate the passive grinding process, and there is a lack of technical and method support for optimizing the grinding work of the rail profile. Summary of the Invention

[0005] In view of this, one of the objectives of the present invention is to provide a prediction method for the passive grinding process of rails, so as to solve the technical problems in the prior art that rail operators combine the grinding processes of different grinding units of a rapid grinding vehicle based on experience, resulting in difficult control of grinding quality, poor wheel-rail contact relationship, and affecting the service life of rails and the running stability of trains.

[0006] Another objective of the present invention is to provide an application of the prediction method for the passive grinding process of rails.

[0007] To achieve the above-mentioned one objective, the present invention provides a prediction method for the passive grinding process of rails, including the following steps:

[0008] Determine the limit of the swing of the grinding wheel during passive grinding of the rail;

[0009] Establish the contact mapping relationship between the passive grinding wheel and different rails at different angles;

[0010] Establish the grinding amount function of a single grinding wheel under different mapping relationships with the rail;

[0011] Based on the grinding units of the rapid rail grinding vehicle, establish the process curve under the process parameters of the grinding wheel combination of different grinding units in a single pass;

[0012] Establish the final grinding process curve under different grinding passes.

[0013] Optionally, determining the limit of the swing of the grinding wheel during passive grinding of the rail includes determining the swing angle and the lateral displacement of the grinding wheel relative to the rail, and the range of the rail covered by the grinding wheel is -15° to +45°.

[0014] Optionally, establishing the contact mapping relationship between the passive grinding wheel and different rails at different angles includes taking the top center of the rail as the origin of the abscissa, the horizontal direction as the abscissa, and the grinding wheel pressing on the rail surface, obtaining the cross-sectional range of the contact surface between the grinding wheel and the rail within the action limit range, represented by Xi, and Xi corresponds to the action range of the grinding wheel relative to the rail in different postures.

[0015] Optionally, the action ranges of Xi are -25 to -5, -20 to 5, -15 to 10, -10 to 15, -5 to 20, 0 to 25, 5 to 25, 10 to 30, 15 to 30, and 20 to 30 respectively.

[0016] Optionally, establishing the contact mapping relationship between the passive grinding wheel and different rails at different angles further includes establishing a mapping relationship library of a single grinding wheel with respect to the rail, and the profiles of the rails are 60, 60D, 60N, 75, or 75N.

[0017] Optionally, the establishment of the grinding volume function under different mapping relationships between a single grinding wheel and the rail includes that, based on the relatively fixed grinding ability of a single grinding wheel relative to the rail, combining the test bench data and on-site experience, the grinding depth value of a single grinding wheel passing through the rail once is about 0.01 mm, and the grinding volume curve of a single grinding wheel in the cross-sectional coordinate system of the rail is obtained, m = f(X i ), where i corresponds to different grinding positions.

[0018] Optionally, the establishment of the grinding volume function under different mapping relationships between a single grinding wheel and the rail further includes establishing a grinding process function library for a single grinding wheel based on the contact mapping relationship of different rail profiles.

[0019] Optionally, the establishment of the process curve under different grinding wheel combination process parameters for a single pass based on the grinding unit of the rail rapid grinding vehicle includes that, based on the same action mode of the grinding wheel and the rail, after the rail rapid grinding vehicle passes through once, the grinding volume distribution curve of the rail cross-section of the rail head with respect to the rail is

[0020] M = ∑m j , where j is different grinding units.

[0021] Optionally, the establishment of the final grinding process curve under different grinding passes includes, based on the single-pass grinding Mi curve, in the coordinate system of the rail head, summing up the Mis under different grinding passes to obtain the grinding process curve after multiple passes of grinding. The abscissa of this curve is the rail head coordinate, and the ordinate is the grinding depth of the rail along the rail head;

[0022] The grinding process curve is F = ∑M k , where k is the number of grinding passes.

[0023] To achieve the second of the above purposes, the present invention also provides an application of the prediction method for the passive rail grinding process as described in any one of the above.

[0024] The prediction method for the passive rail grinding process provided by the present invention has the following technical effects:

[0025] By combining the grinding processes at different action positions between the on-site grinding wheel and the rail, the present invention predicts the grinding volume distribution at different positions under the abscissa of the rail head, and further realizes the pre-judgment of the grinding process, timely adjustment of the grinding process parameters, and the implementation of the passive grinding process and the achievement of the grinding goal.

[0026] The application of the prediction method for the passive rail grinding process provided by the present invention has the following technical effects:

[0027] Based on the conformal contact mapping relationship between the circumferential surface of the rail and the grinding wheel under different rail profiles, a grinding process parameter library for a single grinding wheel is obtained, providing a design basis for the passive grinding process and a process design method for the diversified combination of the rapid grinding operation, filling the gap in the domestic related process methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0029] Figure 1a is a schematic diagram of the grinding of a single grinding wheel in the traditional active grinding;

[0030] Figure 1b is a schematic diagram of the envelope grinding of multiple longitudinal grinding wheels in the traditional active grinding;

[0031] Figure 2a is a schematic diagram of the grinding of a single grinding wheel in the passive grinding;

[0032] Figure 2b is a schematic diagram of the envelope grinding of multiple longitudinal grinding wheels in the passive grinding;

[0033] Figure 3 is a schematic diagram of the action form of the grinding wheel and the rail of the passive grinding device;

[0034] Figure 4 is a schematic diagram of the range limit of the grinding wheel of the passive grinding device;

[0035] Figure 5 is a top view of the action of the circumferential surface passive grinding wheel and the rail;

[0036] Figure 6 is a front view of the action of the circumferential surface passive grinding wheel and the rail;

[0037] Figure 7 is a schematic diagram of the mapping contact relationship of the grinding surface at a typical position of the grinding wheel relative to the rail;

[0038] Figure 8 is Figure 7 the single grinding head grinding process function at position ④ in

[0039] Figure 9 is Figure 8 the four single grinding head combined single-pass through mode in

[0040] Figure 10 is the process flow chart of the prediction method of the rail passive grinding process of the present invention. Detailed implementation manners

[0041] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be described in detail below. Obviously, the described embodiments are only a part rather than all of the embodiments of the present invention. All other implementation manners obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope protected by the present invention.

[0042] For passive rail grinding, grinding is performed using the circumferential surface of the grinding wheel. At present, the implementation and implementation of on-site grinding processes can only rely on subjective prediction and judgment by humans, and cannot objectively design the process parameters of passive grinding, nor can it predict the grinding process under on-site operation parameters. It is difficult to control the grinding process parameters and grinding quality, as Figure 2a and 2b shown.

[0043] For traditional active grinding, as Figure 1a and 1b shown, the traditional rail grinding train drives the grinding wheel to rotate through an electric motor or a hydraulic motor, makes the end face of the grinding wheel contact the top surface of the rail through a constant pressure control system, and realizes the cutting of the rail end face by driving the grinding wheel to rotate through the electric motor. By controlling the power of the grinding motor, the grinding travel speed, and the action angle between the grinding stone and the rail, the control of the grinding amount can be realized, and thus the prediction and formulation of the active grinding process can be realized.

[0044] However, for passive (rapid) grinding, when operating according to the specified grinding pressure and grinding speed, when a single grinding wheel passes over the rail once, the grinding ability of the grinding wheel on the rail is basically constant. Its grinding process (grinding amount at different coordinates) is mainly realized by combining different grinding wheel grinding processes. Therefore, the process design and prediction of passive grinding technology cannot be predicted and compiled through the process scheme of conventional active grinding.

[0045] Based on the above defects, the present invention provides a prediction method for the passive rail grinding process. The following will be described in detail in combination with specific attached Figures 3 - 10 drawings.

[0046] A prediction method for the passive rail grinding process, as Figure 10 shown, includes the following steps:

[0047] The first step: Determine the limit of the swing of the passive rail grinding wheel, the swing angle and the lateral displacement of the grinding wheel relative to the rail, as Figure 3 and Figure 4 shown;

[0048] The second step: Establish the contact mapping relationship between the passive grinding wheel and the rail at different angles;

[0049] Taking the center of the rail top as the origin of the abscissa and the horizontal direction as the abscissa, a single grinding wheel is set as a flexible body with a certain stiffness. By pressing on the rail surface, the cross-sectional range of the contact surface between the grinding wheel and the rail within the action limit range can be obtained, denoted as Xi. Xi corresponds to the action range of the grinding wheel relative to the rail in different postures, as shown in Figures 5 - 7 shown.

[0050] The action ranges of Xi are respectively: ①: -25 to -5, ②: -20 to 5, ③: -15 to 10, ④: -10 to 15, ⑤: -5 to 20, ⑥: 0 to 25, ⑦: 5 to 25, ⑧: 10 to 30, ⑨: 15 to 30, and ⑩: 20 to 30.

[0051] Using the profile dimensions of typical rails such as 60, 60D, 60N, 75, 75N, etc., a mapping relationship library of a single grinding wheel to the rail can be established.

[0052] Step 3: Establish the grinding amount function under different mapping relationships between a single grinding wheel and the rail;

[0053] The grinding ability of a single grinding wheel relative to the rail is relatively fixed. Combining the data of the test bench and on-site experience, the grinding depth value of a single grinding wheel passing over the rail once is about 0.01 mm, and the grinding amount curve of the single grinding wheel in the rail cross-section coordinate system is obtained.

[0054] m = f(Xi), where i corresponds to different grinding positions (1, 2, 3, 4,... 10)

[0055] Based on the contact mapping relationships for different rail types (profile dimensions such as 60, 60D, 60N, 75, 75N, etc.), a grinding process function library for a single grinding wheel can be established.

[0056] As shown in Figure 8 shown, it is the grinding process function when the single grinding wheel is at position ④.

[0057] Step 4: Based on the grinding unit of the rail rapid grinding vehicle, establish the process curve under different process parameters of the grinding wheel combination of different grinding units in a single pass;

[0058] For example, the rail rapid grinding vehicle has 4 grinding units (each grinding unit usually includes multiple grinding wheels). The grinding wheels of each grinding unit are rigidly fixed on the grinding beam. The acting methods of all grinding wheels on the rail are the same. After the grinding vehicle passes once, the grinding amount distribution curve of the rail top cross-section on the rail is

[0059] M = ∑mj, where j is different grinding units (j = 1, 2, 3, 4)

[0060] As shown in Figure 9As shown, it is the single-pass mode of the combination of four grinding units, and "total" is the total grinding amount.

[0061] Step 5: Establish the final grinding process curve under different numbers of grinding passes;

[0062] For example, based on the single-pass grinding Mi curve, in the coordinate system of the rail head, sum up the Mis under different numbers of grinding passes to obtain the grinding process curve after multiple passes of grinding. The abscissa of this curve is the rail head coordinate, and the ordinate is the grinding depth of the rail along the rail head.

[0063] F = ∑Mk, where k is the number of grinding passes (k = 1, 2, 3,..., n)

[0064] To more accurately reflect the passive grinding process, use the rail curvature function before grinding as the interpolation function, perform interpolation and fitting processing to obtain the final grinding process curve.

[0065] The present invention also provides an application of the prediction method for the passive rail grinding process. Here, the application refers to reasonably designing the passive rail grinding process according to the prediction method for the passive rail grinding process.

[0066] The present invention solves the difficulty that the process of the passive grinding technology based on the circumferential surface of the grinding stone is difficult to predict, can scientifically manage the quality of passive (rapid) rail grinding. At the same time, based on the grinding process mode library of a single grinding wheel, any permutation and combination can be realized, enriching the passive grinding process, and providing a reference basis for the scientific formulation of the passive grinding process.

[0067] By adjusting the acting position of the grinding wheel and the rail on-site, predict the final grinding process curve, and judge the reasonable correctness of the on-site operating grinding stone layout parameters.

[0068] The above is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of changes or substitutions, which should all be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A prediction method for passive rail grinding process, characterized in that: The following steps are involved: Determine the limits of grinding wheel swing during passive rail grinding; Establish the contact mapping relationship between the passive grinding wheel and different rails at different angles; Establish the grinding amount function under different mapping relationships between a single grinding wheel and rail; Based on the grinding unit of the rail rapid grinding vehicle, the process curves under different grinding unit grinding wheel combination process parameters in a single pass are established; Establish the final grinding process curve under different grinding passes.

2. The prediction method for passive rail grinding process according to claim 1, characterized in that: Determining the limit of the swing of the grinding wheel during passive rail grinding includes determining the swing angle and lateral displacement of the grinding wheel relative to the rail, and the range of the grinding wheel covering the rail is -15° to +45°.

3. The prediction method for passive rail grinding process according to claim 1, characterized in that: The establishment of the contact mapping relationship between the passive grinding wheel and different rails at different angles includes taking the top center of the rail as the origin of the horizontal coordinate and the horizontal direction as the horizontal coordinate, the grinding wheel is buckled on the rail surface, and the cross-sectional range of the contact surface between the grinding wheel and the rail is obtained within the action limit range, which is represented by Xi, and Xi corresponds to the action range of the grinding wheel relative to the rail in different postures.

4. The prediction method for passive rail grinding process according to claim 3, characterized in that: The effective ranges of Xi are -25 to -5, -20 to 5, -15 to 10, -10 to 15, -5 to 20, 0 to 25, 5 to 25, 10 to 30, 15 to 30 and 20 to 30 respectively.

5. The prediction method for passive rail grinding process according to claim 3, characterized in that: The establishing of the contact mapping relationship between the passive grinding wheel and different rails at different angles also includes establishing a mapping relationship library between a single grinding wheel and the rail, wherein the profile of the rail is 60, 60D, 60N, 75 or 75N.

6. The prediction method for passive rail grinding process according to claim 4, characterized in that: The establishment of the grinding amount function under different mapping relationships between a single grinding wheel and a rail includes: based on the fact that the grinding capacity of a single grinding wheel relative to the rail is relatively fixed, combined with test bench data and field experience, the grinding depth value of a single grinding wheel passing through the rail in a single pass is about 0.01 mm, and the grinding amount curve of the single grinding wheel in the cross-section coordinate system of the rail is obtained, m=f(X i ), i corresponds to different grinding positions.

7. The prediction method for passive rail grinding process according to claim 6, characterized in that: The establishment of the grinding amount function under different mapping relationships between a single grinding wheel and a rail also includes establishing a grinding process function library of the single grinding wheel based on the contact mapping relationship between different rail types of the rails.

8. The prediction method for passive rail grinding process according to claim 6, characterized in that: The process curves under different grinding unit grinding wheel combination process parameters under single pass based on the grinding unit of the rail rapid grinding vehicle include: based on the same action mode of the grinding wheel and the rail, after the rail rapid grinding vehicle passes through a single pass, the grinding amount distribution curve of the cross section of the rail top to the rail is M=∑m j , j is different grinding units.

9. The prediction method for passive rail grinding process according to claim 1, characterized in that: The establishment of the final grinding process curve under different grinding passes includes taking the Mi curve of a single grinding pass as a basis, summing Mi under different grinding passes in the rail head coordinate system, and obtaining a grinding process curve after multiple grinding passes, wherein the abscissa of the curve is the rail head coordinate, and the ordinate is the grinding depth of the rail along the rail head; The grinding process curve is F = ∑M k , k is the number of polishing passes.

10. An application of the prediction method for passive rail grinding process according to any one of claims 1 to 9.

Images