A method for analyzing wear trends and extending service life of subway train wheelsets

Abstract

The present invention discloses a method for analyzing the wear trend and extending the service life of subway train wheelsets, comprising the following steps: (1) collecting and processing relevant data of subway train wheelsets; (2) identifying and determining key parameters and constraint parameters in the data collected in step (1); (3) fitting the wheel rim width development curve based on the least squares method; (4) calculating the economic turning point and the service life of the wheelset; and (5) outputting and analyzing the calculation results. In step (3), the wheel rim width development curve is approximated by polynomial fitting technology, and a satisfactory wheel rim width development curve function is obtained by calibrating the coefficient parameters of the polynomial. The final calculation result is output as the final maintenance strategy to provide guidance to the production department. This is an optimized maintenance strategy for economic turning, which participates in daily maintenance as an auxiliary and is an optimization of the current maintenance strategy of pure "fault repair".

Description

Technical Field

[0001] The present invention belongs to the technical field of subway train wheel wear analysis, and in particular relates to a method for analyzing the wear trend of a subway train wheel pair and extending its service life. Background Art

[0002] Currently, the domestic urban rail transit industry measures the three parameters of vehicle wheelsets during routine maintenance: rim width, rim height, and rim angle. The wheelset diameter and inner distance are used to monitor the condition of the vehicle wheelsets. The maintenance standards for these parameters are interceptive: when the measured value exceeds a certain standard, the wheelset is rotated according to a template. If, after several rotations, the wheelset diameter falls below the standard, the wheelset is scrapped. There are no clear quality control measures for the changing trends of wheelset measurement data. This means that as long as the measured data does not exceed the standard, maintenance personnel assume that the wheelset is in normal condition, regardless of whether the data shows a sharp decrease or increase in the parameters. However, in measurement cycles that are measured on a monthly or quarterly basis, there are obvious safety risks. Summary of the Invention

[0003] Purpose of the invention: The purpose of the present invention is to address the deficiencies in the prior art and to provide a method for analyzing the wear trend and extending the service life of subway train wheelsets, as well as an optimized maintenance strategy for economical turning repairs. The strategy participates in routine maintenance as an assistant and is an optimization of the current maintenance strategy of pure "fault repair."

[0004] Technical solution: The method for analyzing the wear trend of subway train wheelsets and extending their service life according to the present invention comprises the following steps:

[0005] (1) Collect and process relevant data of subway train wheelsets;

[0006] (2) Identify and determine the key parameters and constraint parameters in the data collected in step (1);

[0007] (3) Fitting the rim width development curve based on the least squares method;

[0008] (4) Calculate the economic turning point and service life of the wheelset;

[0009] (5) Output and analysis of calculation results.

[0010] Furthermore, the key parameter in step (2) is the wheel rim width SW; the constraint parameter is the wheel diameter D.

[0011] Furthermore, in step (3), the rim width development curve is approximated by polynomial fitting technology, and a satisfactory rim width development curve function is obtained by calibrating the coefficient parameters of the polynomial.

[0012] Furthermore, nonlinear functions are introduced Normalization method of polynomial fitting, the rim width development curve It is expressed as the following polynomial using a standard normalization method:

[0013] .

[0014] Furthermore, the coefficient parameters of the polynomial are effectively calibrated by the least square method, and the steps of polynomial fitting based on the LSM rim width development curve are as follows:

[0015] 1) Draw a rough graph of the function from the known data - a scatter plot, and determine the degree n of the fitted polynomial;

[0016] 2) List calculation and ;

[0017] 3) Write the normal equations and solve for a0, a1, …, an;

[0018] 4) Write the fitting polynomial .

[0019] Furthermore, step (4) includes: calculating the maximum kilometer value D of the wheel within the rated wheel diameter range Max ,Right now:

[0020] D Max =D+ Number of turning repairs

[0021] Where D is the input value of the wheelset diameter, and the number of turnings is the remaining turnable wheel diameter divided by the wheel diameter consumed in a single turning. Develop a curve for the rim width;

[0022] Return to D Max The turning mileage X when it is the maximum is the economic turning mileage of the wheelset. At the same time, D MAX The maximum value of is the maximum wheelset life.

[0023] Furthermore, the specific model of step (4) is constructed as follows:

[0024] The economic turning point determination model based on SW curve and D value constraint is established as follows:

[0025] (1)

[0026] st

[0027] (2)

[0028] In the above formula, is the mileage of economic repair points; N is the number of economic repairs; The mileage of the wheelset after the last economical turning; The wheel diameter cutting value for each economic turning; The maximum allowable wheel diameter cutting value.

[0029] Furthermore, formula (1) is the objective function, which represents the maximum wheel set mileage corresponding to is the economic turning point, and equation (2) is the constraint condition, in which:

[0030] (3)

[0031] In the above formula, The change in rim width after each economic turning; is the wheel diameter cutting ratio corresponding to the change in wheel rim width; This is the standard rim width.

[0032] Beneficial effects: The present invention can determine whether there is unilateral wear based on the trend changes of wheelset parameters. By replacing the left and right wheelsets and the strategy of replacing the power and non-powered wheelsets, maintenance costs can be reduced, reliability can be improved, and the service life of the wheelsets can be extended.

[0033] When the detection data deteriorates sharply, the metal fatigue and wear of the wheelset are intervened by rotating the wheel earlier, rather than waiting until the measurement data exceeds the standard value. The service life of the wheelset is extended through comprehensive maintenance strategies. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 The flowchart of one embodiment of the present invention is shown in FIG. DETAILED DESCRIPTION

[0035] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0036] In the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "inside", "outside", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the present invention.

[0037] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0038] The present invention will be further described in detail below through specific implementation examples in conjunction with the accompanying drawings.

[0039] like Figure 1 As shown, a method for analyzing the wear trend of subway train wheelsets and extending their service life of the present invention includes the following steps:

[0040] (1) Collect and process relevant data of subway train wheelsets.

[0041] (2) Identify and determine the key parameters and constraint parameters in the data collected in step (1), where the key parameter is the wheel rim width SW; the constraint parameter is the wheel diameter D. Among the four types of wheelset size parameters, the wheel rim width SW is selected as the main parameter for wheelset size parameter research. At the same time, since the wheel diameter cannot be less than a specific threshold (770 mm), the wheel diameter D is used as the constraint parameter.

[0042] It's important to note that the selection of key parameters is a variable. Our definition of key parameters refers to the parameters that dominate the entire maintenance process. For a particular subway line, since SD is the dominant parameter, a model using SD as the primary parameter and D as the secondary parameter is selected for fitting calculations. This is not a fixed rule. For example, on another subway line, AC07 trains also used SD as the dominant parameter, but experienced a sharp drop in Qr values. During this period, Qr replaced SD as the key parameter. Similarly, AC15 and AC18 trailers used tread groove depth as the key parameter. Even on a relatively stable line, individual trains have experienced abnormal coaxial wheel diameter differences. Strictly speaking, during these abnormal periods, coaxial wheel diameter differences are the key parameter. Beyond the key parameters, the algorithm and process are generally applicable.

[0043] (3) Fit the rim width development curve based on the least squares method.

[0044] In order to fit the rim width development curve as accurately as possible, we do not make any prior assumptions about its curve function. Instead, we choose to approximate it using polynomial fitting techniques and obtain a satisfactory rim width development curve function by calibrating the coefficient parameters of the polynomial.

[0045] Introducing nonlinear functions Normalization method of polynomial fitting, the rim width development curve It is expressed as the following polynomial using a standard normalization method:

[0046]

[0047] Generally speaking, when n=5, we can already approximately express a non-catastrophic, non-multi-extreme, single-valued relationship, namely:

[0048]

[0049] In the above formula, is the fitting error term.

[0050] The coefficient parameters of the fitting polynomial of the above wheel rim width development curve can be effectively calibrated by using the least square method. The steps of fitting the polynomial of the wheel rim width SW development curve based on LSM are as follows:

[0051] 1) Draw a rough graph of the function from the known data - a scatter plot, and determine the degree n of the fitted polynomial;

[0052] 2) List calculation and ;

[0053] 3) Write the normal equations and solve for a0, a1, …, an;

[0054] 4) Write the fitting polynomial .

[0055] (4) Calculate the economic turning point and service life of the wheelset.

[0056] Assume that there are mileages X for each wheel, and calculate the maximum mileage value D of the wheel within the rated wheel diameter range (844mm to 770mm). Max ,Right now:

[0057] D Max =D+ Number of turning repairs

[0058] Where D is the input value of the wheelset diameter, and the number of turnings is the remaining turnable wheel diameter divided by the wheel diameter consumed in a single turning.

[0059] Return to D Max The turning mileage X when it is the maximum is the economic turning mileage of the wheelset. At the same time, D MAX The maximum value of is the maximum wheelset life.

[0060] The specific model construction is as follows:

[0061] The economic turning point determination model based on SW curve and D value constraint is established as follows:

[0062] (1)

[0063] st

[0064] (2)

[0065] In the above formula, is the mileage of economic repair points; N is the number of economic repairs; The mileage of the wheelset after the last economical turning; The wheel diameter cutting value for each economic turning; The maximum allowable wheel diameter cutting value.

[0066] Formula (1) is the objective function, which represents the maximum wheel set mileage corresponding to Repair some points for the economy.

[0067] Formula (2) is the constraint condition, which includes:

[0068] (3)

[0069] In the above formula, The change in rim width after each economic turning; is the wheel diameter cutting ratio corresponding to the change in wheel rim width; is the standard rim width; other parameters have the same meanings as before.

[0070] (5) Output and analysis of calculation results.

[0071] We output the final calculation results as the final maintenance strategy to provide guidance to the production department. The current maintenance strategy mainly includes two contents:

[0072] 1. The number of kilometers for which the wheelset requires economical turning (economic turning points).

[0073] 2. The mileage at which the wheelset is worn out and needs to be replaced.

[0074] For wheelsets, the project team believes that in addition to the two general states of fault and non-fault, it is also necessary to define their wear status to tell technicians what the current wheelset wear rate is like, whether they should maintain this rate of wear, or use maintenance measures to slow down or even speed up the rate.

[0075] According to the calculated economic lapping mileage, calculate the average wear during the economic lapping cycle, which is defined as:

[0076] Ka = wheel rim width wear value / economic turning and repair mileage

[0077] The instantaneous change rate K of the wheelset measurement data is defined as the change rate of SW between two adjacent measurements of the wheelset, that is, the slope of the straight line between two adjacent data, that is,

[0078] K = wheel rim width wear between two consecutive measurements / mileage difference between two consecutive measurements

[0079] The limit wear rate of wheelset Kmax is defined as the maximum change rate of SW within the economic turning and repair cycle, that is,

[0080] Kmax = the width of the standard range of wheel rim width / economical turning and repair mileage

[0081] Among them, the amplitude of the standard range of wheel flange width is the maximum value minus the minimum value of the wheel flange width standard. For example: the wheel flange width standard of AC07 train on Line 8 is 26.5~33mm, so its amplitude is 33-26.5=6.5mm.

[0082] Based on these three parameters describing the rate of change of wheel flange width SW, the status definition and early warning mechanism of wheelset data are designed with K as the control parameter, as shown in the following table:

[0083] state Maximum rate of change Minimum rate of change Is there an early warning? Economic wear and tear Ka 0 no Accelerated wear state Kmax Ka Yes, mark "accelerate" Fault status Kmax Yes, mark "fault"

[0084] This is an optimized maintenance strategy for economical turning repairs. It participates in daily maintenance as an assistant and is an optimization of the current maintenance strategy of pure "fault repair".

[0085] The method of the present invention is applicable to the quality management process of base-level wheelset maintenance, including:

[0086] The first input layer contains the measurement of wheelset parameters (data input and error detection);

[0087] The second step is the calculation layer, which includes the calculation of economic maintenance mileage and the maximum service life of the wheelset;

[0088] The third step is the output layer, which includes maintenance strategies, wheelset status, and data warnings.

[0089] The existing one-size-fits-all maintenance methods also affect the service life of wheelsets. According to the trend changes of wheelset parameters, we can know whether there is unilateral wear. By replacing the left and right wheelset positions, and the strategy of replacing the powered and non-powered wheelsets, we can reduce maintenance costs and improve reliability, and extend the service life of wheelsets. When the detection data deteriorates sharply, we can intervene in the metal fatigue and wear of the wheelset by rotating the wheels earlier, rather than waiting until the measurement data exceeds the standard value. The service life of the wheelset can be extended through comprehensive maintenance strategies.

[0090] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as a preferred embodiment as above, it is not intended to limit the present invention. Any technician familiar with this profession can make some changes or modifications to equivalent embodiments of the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A method for analyzing the wear trend of subway train wheelsets and extending their service life, characterized by: The steps include: (1) Collect and process relevant data of subway train wheelsets; (2) Identify and determine the key parameters and constraint parameters in the data collected in step (1); (3) Fitting the rim width development curve based on the least squares method; (4) Calculate the economic turning point and the service life of the wheelset, and calculate the maximum mileage value D of the wheel within the rated wheel diameter range Max ,Right now: D Max =D+SW(x)*number of turning and repairing times Where D is the input value of the wheelset diameter, the number of turning times is the remaining turnable wheel diameter divided by the wheel diameter consumed in a single turning, and SW(x) is the wheel flange width development curve; Return to D Max The turning mileage X when it is the maximum is the economic turning mileage of the wheelset. At the same time, D Max The maximum value of is the maximum wheelset life; (5) Output and analysis of calculation results.

2. The method for analyzing wear trends and extending service life of subway train wheelsets according to claim 1, characterized in that: The key parameter in step (2) is the wheel rim width SW; the constraint parameter is the wheel diameter D.

3. The method for analyzing wear trends and extending service life of subway train wheelsets according to claim 1, characterized in that: In step (3), the rim width development curve is approximated by polynomial fitting technology, and a satisfactory rim width development curve function is obtained by calibrating the coefficient parameters of the polynomial.

4. The method for analyzing wear trends and extending service life of subway train wheelsets according to claim 3, characterized in that: A normalization method of polynomial fitting of the nonlinear function y=f(x) is introduced, and the rim width development curve SW(x) is expressed as the following polynomial using a standard normalization method: SW(x)=a0+a1·x 1 +a2·x 2 +a3·x 3 +…+a n ·x n +…。 5. The method for analyzing wear trends and extending service life of subway train wheelsets according to claim 3, characterized in that: The coefficient parameters of the polynomial are effectively calibrated by the least square method. The steps of polynomial fitting based on the LSM wheel rim width development curve are as follows: 1) Draw a rough graph of the function from the known data - a scatter plot, and determine the degree n of the fitted polynomial; 2) List calculation and 3) Write the normal equations and solve for a0, a1, …, an; 4) Write the fitting polynomial 6. The method for analyzing wear trends and extending service life of subway train wheelsets according to claim 1, characterized in that: The specific model of step (4) is constructed as follows: The economic turning point determination model based on SW curve and D value constraint is established as follows: MAX N·l e +l s (1) st In the above formula, l e is the mileage of economic repair points; N is the number of economic repairs; l s The mileage of the wheelset after the last economical turning; d i The wheel diameter cutting value for each economic turning; ΔD max The maximum wheel diameter allowed is cut.

7. The method for analyzing wear trends and extending service life of subway train wheelsets according to claim 6, characterized in that: Formula (1) is the objective function, which means the l corresponding to the maximum mileage of the wheelset e is the economic turning point, and equation (2) is the constraint condition, where: In the above formula, ΔSW i is the change in rim width after each economic turning and repair; u is the wheel diameter cutting ratio corresponding to the change in rim width; This is the standard rim width.

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