Wheel wear identification on a rail vehicle

Abstract

The invention relates to a method for identifying the wear of the running surface of at least one wheel (3) of a rail vehicle (1, 2) by ascertaining the wheel diameter, comprising the following steps - measuring the rotational speed (n) of the at least one wheel (3) with a rotational speed sensor (4A), - determining a first speed measurement variable (v1(t)) of a translational speed (v(t)) of the rail vehicle (1, 2) on the basis of the measured rotational speed (n), - determining a second speed measurement variable (v2(t)) of the translational speed (v(t)) of the rail vehicle (1, 2) by means of another method which is independent of the wheel diameter (d) of at least one wheel (3) of the rail vehicle (1, 2), - comparing the first speed measurement variable (v1(t)) determined by means of the rotational speed (n) and the speed (v2(t)) determined by means of a method which is independent of the wheel diameter, and - ascertaining the current wheel diameter (d(t)) by means of the result of the comparison.

Description

[0001] Wheel wear detection in a rail vehicle

[0002] The invention relates to a method for detecting the wear of the running surface of at least one wheel of a rail vehicle by determining the wheel diameter using a first measuring method, comprising the steps of measuring the rotational speed of the at least one wheel using a speed sensor and determining a first speed measurement variable of a translational speed of the rail vehicle on the basis of the measured rotational speed.

[0003] DE 3148401 A1 discloses a device for determining the wheel diameter of a rail vehicle. In this device, a counting process is started and stopped by switching devices mounted on the trackside via a vehicle-mounted sensor when the rail vehicle, of which the wheel diameter of at least one wheel is to be determined, travels through a measuring section provided for this purpose. The counter reading measured in this process is then transferred to an evaluation circuit which comprises a clock generator, a memory, a divider for counting down the measured counter reading, a second counter and a timer, the timer determining the length of the evaluation process with a time period determined with the aid of known variables such as the frequency of the clock generator, the length of the measuring section and the number of pulses triggered by one or more wheel pulse generators per wheel revolution.At the end of the evaluation process, the second counter provides a value for the wheel diameter, which can be used for further evaluations, such as determining the actual distance traveled. The invention is based on the object of providing an improvement over the prior art for a method for detecting the wear of the tread of at least one wheel of a rail vehicle by determining the wheel diameter of the type mentioned above. Furthermore, it is an object of the invention to provide an arrangement for carrying out this method.

[0004] According to the invention, this object is achieved by a method according to claim 1 and an arrangement according to claim 11. Dependent claims specify advantageous embodiments of the invention.

[0005] The method according to the invention for detecting the wear of the running surface of at least one wheel of a rail vehicle by determining the wheel diameter comprises the following steps:

[0006] - Measuring the speed of at least one wheel with a speed sensor,

[0007] - Determination of a first speed measurement value of a translational speed of the rail vehicle based on the measured speed,

[0008] - Determination of a second speed measurement variable of the translational speed of the rail vehicle by means of a second measuring method independent of the wheel diameter of at least one wheel of the rail vehicle,

[0009] - Comparison of the first speed measurement and the second speed measurement and

[0010] - Determination of the current wheel diameter using the comparison result.

[0011] The speed sensor or rotary pulse sensor according to the state of the

[0012] Technology for measuring the speed of a wheel is arranged in the vicinity of either a running axle or a driving axle of the rail vehicle.

[0013] In a cost-effective design, the speed sensor or rotary pulse sensor is mounted on the axle cover as standard in order to provide measured values ​​for train protection systems, anti-skid and anti-spin systems or a train control and management system TCMS (Train Control & Management System).

[0014] The wheel diameter of the rail vehicle is advantageously stored in a measuring, evaluation or control device during commissioning.

[0015] As part of the maintenance of the rail vehicle, the wheel diameter is usually measured stationary, in particular after the wheels have been turned during the maintenance, and a new reference value for the wheel diameter is stored in the device provided for this purpose.

[0016] The extent of wear on the tread of a wheel of a rail vehicle is determined, among other things, by the operating life of this rail vehicle but also by the type and condition of the track of at least one rail network used during this operating life.

[0017] It is advantageous if the determination of the first speed measurement variable and the determination of the second speed measurement variable takes place during a measuring period whose duration is determined by a maximum characteristic time constant of the two measuring methods. Such characteristic time constants can, for example, be between 1 s and 20 s. The respective characteristic time constant is determined by the measuring method and indicates how long the measurement must be taken in order to determine a sufficiently accurate value for the corresponding speed measurement variable. For sufficient accuracy, the duration of the measuring period is chosen between 1 minute and 30 minutes. The duration of the measuring period is preferably chosen between 3 minutes and 10 minutes.

[0018] It is advantageous if the two determined speeds of the rail vehicle remain within a speed range defined by a lower speed limit and an upper speed limit during the measurement period.

[0019] This ensures that the velocity measurement determined from the ensemble of measurement points during the measurement period is a sufficiently accurate representation of the ensemble of measurement points used to determine it for further processing.

[0020] In a preferred embodiment, the lower speed limit is 80 km / h.

[0021] The lower speed limit is 90 km / h in another inexpensive version.

[0022] The difference between the upper speed limit and the lower speed limit is preferably 10 km / h. In a variant of the method according to the invention, a method for determining the second speed measurement variable that is independent of the wheel diameter is a method for determining the speed using a vehicle-mounted GNSS receiver.

[0023] In one variant of this method, the recording rate is 1Hz.

[0024] With this method of speed determination, the minimum translational speed v ( t ) of the rail vehicle should not be less than 70 km / h to ensure a sufficient signal-to-noise ratio (SNR) of the output signal of the GNSS receiver.

[0025] This GNSS receiver for determining a speed measurement value independent of the wheel diameter is advantageously already installed in rail vehicles equipped with odometry or telemetry systems.

[0026] In a further variant of the method according to the invention, a method for determining the second speed measurement variable which is independent of the wheel diameter is a method for determining the speed by recording trackside position markings by recording devices arranged on the rail vehicle.

[0027] The recording device is, for example, a camera that is designed to process signals in the range of the visible radiation spectrum.

[0028] Preferably, the camera is configured to process signals in the thermal radiation spectrum (infrared spectrum). In a particularly advantageous embodiment, the recording device is a stereoscopic arrangement of two cameras.

[0029] In an alternative embodiment, the receiving device is a radio receiver which receives signals from route markers provided with transmitting devices.

[0030] In an advantageous embodiment of the method, a wheel diameter of at least one wheel of a rail vehicle is determined continuously or at selectable time intervals and, when a predetermined lower limit value of a wheel diameter is approached, a warning is transmitted to a control station of the rail vehicle.

[0031] It is advantageous if an error message is transmitted to a control station of the rail vehicle when this set lower limit is undershot.

[0032] For the method according to the invention, it is advantageous to determine values ​​of the distance traveled by the rail vehicle by numerically integrating the translational speeds over the period of a measuring interval, in particular by summing the products of the speeds at sampling times and the sampling interval over the measuring period, and to determine a relative error value therefrom.

[0033] The numerical integration is performed using state-of-the-art numerical integration methods. In an advantageous embodiment of the method according to the invention, the wheel diameter, determined continuously or at selectable time intervals, and the relative error, determined continuously or at selectable time intervals, are stored as time series data in a vehicle-mounted or external storage device.

[0034] In a preferred embodiment, the parameters determined from the measured values, such as the current wheel diameter and the relative error, are first recorded on the vehicle side via a telemetry system of the rail vehicle manufacturer and then transmitted to a trackside control center of the infrastructure operator or a maintenance platform of the vehicle owner.

[0035] An example of such a telemetry system is the Plasser Datamatic 2 . 0 .

[0036] In a favorable development of the method, the data time series of the wheel diameter and the relative error stored in a vehicle-side or external storage device are used for medium-term and long-term analyses of the wear of at least one wheel of a rail vehicle.

[0037] The analyses can focus on the decrease in the wheel diameter and the resulting increase in the relative error value, which is calculated from a first speed measurement and a second speed measurement, over a period of weeks, months, or years. In a favorable development of the method according to the invention, the parameters of meaningful mathematical models of the temporal progression of the wear of at least one wheel diameter and the relative error are determined based on the analysis of the data time series.

[0038] In an advantageous embodiment of the method, forecasts for the future temporal progression of the wear of the wheel diameter and the increase of the relative error depending on the operation of the rail vehicle are created on the basis of these parameterized mathematical models.

[0039] To carry out the method according to the invention, an arrangement is provided comprising a first measuring device for determining a first speed measurement variable by means of a speed of at least one wheel of the rail vehicle measured with a speed sensor, a second measuring device for determining a second speed measurement variable of the translational speed of the rail vehicle by means of a method independent of the wheel diameter of the at least one wheel, an evaluation device which determines the wheel diameter on the basis of a comparison between the two determined speed measurement variables, a vehicle-side or external storage device which stores data time series of the wheel diameter and the relative error and a communication device which transmits warnings and / or error messages to the control center of the rail vehicle as a function of the position of the wheel diameter at a fixed lower limit value.

[0040] In a preferred embodiment, the warning is sent as a message via an email service or via an online portal to a fleet or maintenance manager of the vehicle owner or one of its service partners.

[0041] In a preferred embodiment, an external storage device is part of a maintenance platform which is designed to store, analyse and process operating status data of at least one rail vehicle.

[0042] Examples of such maintenance platforms include the Machine Condition Observer from Track Machines Connected Gesellschaft m . b . H , or the Boom Maintenance Manager from Boom Software AG .

[0043] It is advantageous if the operating organisations of the maintenance platforms and their components, as bodies responsible for maintenance, have a certification for the maintenance of rail vehicles.

[0044] Such a certification is, for example, an ECM certificate as regulated in Implementing Regulation (EU) 2019 / 779 and Directive (EU) 2016 / 798 of the European Union.

[0045] The invention is explained below by way of example with reference to the accompanying figures. They show schematically:

[0046] Fig . 1 A traction unit of a rail vehicle with measuring devices for the comparative determination of its translational speed .

[0047] Fig. 2 An overall view of the rail vehicle with the power car from Fig. 1. Fig. 3 A temporal speed curve of a rail vehicle during the duration of a measurement.

[0048] Fig . 4a A representation according to Fig . 3 based on the first measurement method .

[0049] Fig . 4b A representation according to Fig . 3 based on the second measuring method .

[0050] Fig . 5a A determined time course of the distance travelled based on the first measurement method .

[0051] Fig . 5b A determined time course of the distance travelled based on the second measurement method .

[0052] Fig . 6 An evaluation of the data time series of the wheel diameter over a period .

[0053] Fig . 7 An evaluation of the relative path error over one period .

[0054] Figure 1 shows the traction unit 1 of a rail vehicle 2 with bogies 3 and a pantograph 8, in which a measuring device 4 according to the invention, an evaluation device 5, a storage device 6 and a communication device 7 as well as the sensors 4A, 4B, 4G and 4D belonging to the different measuring methods for detecting the translational speed of the rail vehicle are schematically arranged. The sensor 4A, which is attached in the vicinity of a wheel axle, measures the speed n of at least one wheel or wheelset by means of magnetic, inductive, optical or other sensor principles and transmits its measured value wired or wirelessly to the measuring device 4. The speed of a point on the running surface of a wheel 3 of the rail vehicle 2 is proportional to the speed n.With the idealized assumption of a circular wheel tread and its concentric position to the wheel axis, the proportionality factor is the circumference U, which in turn is linked to the diameter d via the number n. Therefore,

[0055] (1) v = U- n = 7i-dn if one additionally assumes that the ideally circular wheel rolls on the rail without slippage.

[0056] Formula (1) shows that to determine the speed using the sensor 4A, knowledge of the wheel diameter d is required. From the prior art, it is known that the nominal diameter of a brand-new wheel d N gradually decreases during operation of the rail vehicle due to wear of the wheel tread in contact with the rail and the wheel diameter d is therefore time-dependent

[0057] (2) d = d(t).

[0058] In contrast, the sensor 4B provides a speed determination by evaluating a GNSS

[0059] Receiving device of received data using relationships based on the Doppler effect, a speed measurement value v2(t) which is independent of the wheel diameter d(t) of the rail vehicle 2. Thus, the actual wheel diameter d(t) can be determined by

[0060] Conversion of formula (1) can be calculated

[0061] If formula (1) is inserted into formula (3) we get

[0062] In terms of measurement, the speed value v2(t) used to determine the time-dependent wheel diameter d(t) is measured during a time period t M determined, whereby this measurement time t M sufficiently large in relation to the time constants i relevant for the different measurement methods kwith a first time constant ii for determining the first speed measurement variable v2(t) (first measurement method, k=1) and with a second time constant i2 for determining the second speed measurement variable v2(t) (second measurement method, k=2)

[0063] An alternative measuring method for determining a speed measurement variable v2(t) that is independent of the wheel diameter d(t) is provided by the measuring device 4G with at least one sensor 4D. With this on-board measuring device 4G, when the traction unit 1 of a rail vehicle 2 passes by, the known coordinates of trackside markings are recorded, read out, or received by means of the at least one sensor 4D, and from this the speed v2(t) is determined without knowledge of the current wheel diameter d(t). The determination of this wheel diameter d(t) is carried out analogously to the above-mentioned

[0064] Method that uses the relationship from formula (3).

[0065] In the evaluation device 5, the determined wheel diameter d(t) can be compared with a predetermined value for the minimum permissible wheel diameter d min be compared. In operational cases,

[0066] If this minimum value d is exceeded min Due to the wheel diameter d(t), the evaluation device 5 sends an error message via the communication device 7.

[0067] In addition to the minimum wheel diameter d min a tolerance range Ad is specified, a warning is sent via the communication device 7 if the wheel diameter d(t) is within the tolerance range Ad above the minimum diameter d min lies

[0068] ( 7 ) d min + Ad > d(t) > d min .

[0069] In the evaluation device 5, the starting point s ref travelled distance s (t) by integrating the values ​​determined with the measuring methods using the sensors 4A and 4B or the sensor arrangement 4C and 4D

[0070] Velocity measurements v2(t) and v2(t) are determined:

[0071] (8) s(t) - s ref = J v(t)dt. T s ref

[0072] To evaluate the definite integral shown in formula (8) between the time t sre f at which the rail vehicle 2 is at the reference location s re f and a time t>t sre f numerical integration methods according to the state of the art are carried out in the evaluation device 5 .

[0073] In particular, the determination of a respective calculation value Si(t) , 82(f) for the distance s (t) travelled is carried out by summing the products of the velocities v2(t n ) , v2(t n ) at sampling times t n and the sampling interval At n =t n+ itn .

[0074] With formula (8) or the numerical integration methods, which determine in the evaluation device 5 approximate values ​​of the continuous determinate integration shown in formula (8) for the measuring methods described above, one obtains, depending on the processed speed measurement variable v2(t) or v2(t), the calculated values ​​s2(t) or s2(t) for the starting from a reference location s re f distance s (t) traveled by the rail vehicle.

[0075] These calculation values ​​s2(t) and s2(t) are increased with increasing wear of at least one wheel 3 and the resulting reduction of the wheel diameter d(t) compared to a nominal value d N or a reference value d re f, which is used in the measurement method 1 to determine a first speed measurement variable v2(t) of the translational speed v(t) of the traction unit 1 or the rail vehicle 2, in order to deviate from each other by the difference As (t)

[0076] (9) As(t) = Si(t) -s2(t).

[0077] From this deviation As (t) the evaluation device determines

[0078] 5 a relative error As related to s2(t) rei (t) , which for reasons of better representation is calculated in m / km, which corresponds to multiplication by the factor 1000.

[0079] The calculation variables Si(t) and s2(t) determined in the evaluation device 5 can also be used for a method of determining the wheel diameter d(t) which is alternative to formula (3).

[0080] The number of wheel revolutions N on the distance s (t) travelled by the traction unit 1 of the rail vehicle 2 is calculated from the first speed measurement variable v2(t) determined by the sensor 4A.

[0081] From this, the evaluation device 5 determines, analogously to the relationship of formula (3), the current value of the wheel diameter d(t) from the path s2(t) calculated by means of the second speed measurement variable v2(t) determined by the sensor 4B or the sensor arrangement 4C and 4D

[0082] If the current wheel diameter d(t) and the relative error As defined above rei (t) recorded by the arrangement of sensors 4A and 4B or the sensor arrangement 4G and 4D, the measuring device 4 and the evaluation device continuously or at selectable time intervals, one obtains data time series ( (d ( t2) , d ( t2) , , d ( t n ) ) ; ( As rei ( ti) , ASrei ( t2) ,..., ASrei ( t n ) ) ) , where ti <t2<...<t nwhich can be stored in the storage device 6. This storage device 6 is arranged either within the power car 1, within another part of the rail vehicle 2 or outside the rail vehicle 2.

[0083] Figure 2 shows a variant of the arrangement of Figure 1. Sensors 4A and 4B, a measuring device 4, an evaluation device 5, a vehicle-side storage device 6 and a communication device 7A, 7B are arranged in a rail vehicle 2 with a power car 1, bogies 3 and pantographs 8. In this case, a control station 9A and 9B is arranged both in the power car 1 and in the part of the rail vehicle 2 driven by the power car 1. Data, information and messages can be exchanged between these two control stations 9A and 9B via communication devices such as the wireless transmitting and receiving devices 7A and 7B. This applies in particular to warnings and error messages in the event that the currently determined wheel diameter d(t) is either within the tolerance range according to formula (6) or exceeds the specified lower limit d minThe data time series of the wheel diameter d ( t ) and the relative error As stored in the storage device 6 can also be rei from the control station 9B via the communication devices 7B and 7A to the control station 9A if, for example, devices for analyzing or displaying these data time series are arranged in this control station 9A.

[0084] Figures 3 , 4a and 4b show the course of the translational speed v ( t ) of the rail vehicle

[0085] 2 . To determine the speed measurement

[0086] Vi ( t ) from the measured values ​​of sensor 4A and the velocity measurement variable v2(t) from the measured values ​​of sensor 4B or the sensor arrangement 4G and 4D, two conditions must be met. Firstly, the duration t M of the measurement period must be at least as large as the largest time constant Tk characteristic of the respective measurement method k, maxOn the other hand, the velocity v(t) during this measurement period t M above a lower speed limit v mln and below an upper speed limit v max lay

[0087] (13) Vmin < V(t) < V max .

[0088] Figures 5a and 5b show the course of the travelled path s (t) , whereby in Figure 5a the travelled path Si(t) is shown, which starts from a starting point s re f at a time t Sre f is calculated by a numerical integration method from the velocity measurement value v2(t) shown in Figure 4a and analogously in Figure 5b with 82(f) that from the same starting point s re f is shown, which results from numerical integration of the speed measurement variable v2(t) shown in Figure 4b.

[0089] Figures 6 and 7 show graphical evaluations of the data time series recorded and stored at specific times for the wheel diameter d(t) and the relative error As rei (t) during a period defined by time units M1 to M7. In this case, these time units M1 to M7 are months of a year.

[0090] These data time series d(ti) , d(t2) ,..., d(t n ) and As r ei(ti) , ASrei ( t2) ,..., ASrei ( t n ) can be approximated by linear functions during the evaluation period of seven months Ml , M2 , ... M7 .

[0091] The subject matter of the invention is not limited to the exemplary embodiments illustrated in the figures. Further arrangements for implementing the method according to the invention and further computational and statistical analyses and graphical representations are also encompassed by the claims.

Claims

Patent claims 1. Method for detecting the wear of the running surface of at least one wheel (3) of a rail vehicle (1, 2) by determining the wheel diameter (d) by means of a first measuring method, comprising the following steps: - measuring the rotational speed (n) of the at least one wheel (3) with a speed sensor (4A), - determining a first speed measurement variable (v2(t)) of a translational speed (v(t)) of the rail vehicle (1, 2) on the basis of the measured rotational speed (n), characterized by the following further steps: - determining a second speed measurement variable (v2(t)) of the translational speed (v(t)) of the rail vehicle (1, 2) by means of a second measuring method which is independent of the wheel diameter (d) of the at least one wheel (3) of the rail vehicle (3), - comparing the first speed measurement variable (v2(t)) and the second speed measurement variable (v2(t)), and - determining the current Wheel diameter (d(t) ) using the comparison result.

2. Method according to claim 1, characterized in that the determination of the first speed measurement variable (v2(t) ) and the determination of the second speed measurement variable (v2(t) ) takes place during a measurement period whose duration (t M ) is determined by a maximum characteristic time constant (ik,max) of the two measuring methods.

3. Method according to claim 2, characterized in that the speed measurement variables (v2(t) , v2(t) ) of the rail vehicle (1, 2) during the measurement period (t M ) within a speed limit defined by a lower speed limit (v min ) and by an upper speed limit (v max ) specified speed range ( v mln <v ( t ) <v max ) remain.

4. Method according to one of claims 1 to 3, characterized in that the second speed measurement variable (v2(t)) is determined by means of a vehicle-side GNSS receiver (4B).

5. Method according to one of claims 1 to 3, characterized in that the second speed measurement variable (v2(t)) is determined by means of the vehicle-side recording (4G, 4D) of track-side position markings.

6. Method according to one of claims 1 to 5, characterized in that the wheel diameter (d(t) ) is determined continuously or at selectable time intervals and when approaching a fixed limit value (d m in) a warning is transmitted to a control station (9A, 9B) of the rail vehicle (1, 2).

7. Method according to one of claims 1 to 5, characterized in that the wheel diameter (d(t) ) is determined continuously or at selectable time intervals and if it falls below a fixed limit value (d m in) an error message is transmitted to a control station (9A, 9B) of the rail vehicle (1, 2).

8. Method according to one of claims 1 to 7, characterized in that the determination of measured values ( (si) , (S2) ) of a travelled path (s (t) ) by numerical integration of the speed measured variables (vi(t) , v2(t) ) over the measurement period (t M ) and that this results in a relative Error (As rei (t) ) is determined.

9. Method according to claim 8, characterized in that the wheel diameter (d(t)) determined continuously or at selectable time intervals and the relative error (As r ei(t) ) as data time series ( (d(ti) , d(t2) ,..., d(t n ) ) ; ( As r ei(ti) , ASrei ( t2ASrei ( t n ) ) ) are stored in a vehicle-side or external storage device (6).

10. The method according to claim 9, characterized in that the data time series (d (ti) , d (t2) , ..., d (t n ) ) ; ( As r ei (ti) , As rei ( t2) , , As rei (t n ) ) ) of the wheel diameter (d (t) ) and the relative error (As r ei(t) ) for medium-term and long-term analyses of Wear of at least one wheel (3) of a rail vehicle (1, 2).

11. Arrangement for carrying out the method according to one of claims 1 to 10, comprising a first measuring device (4, 4A) for determining a first speed measurement variable (v2(t)) by means of a speed sensor (4A) measured speed (n) of at least one wheel (3) of the rail vehicle (1, 2), characterized by a second measuring device (4, 4B, 4C, 4D) for determining a second speed measurement variable (v2(t)) of the translational speed (v(t)) of the rail vehicle (1, 2) by means of a method independent of the wheel diameter (d) of the at least one wheel (3), an evaluation device (5) which determines the wheel diameter (d) based on a comparison between the two determined speed measurement variables (v2(t), v2(t)), a vehicle-mounted or external storage device (6) which stores data time series ( (d(ti) , d(t2) ,..., d(t n ) ) ; ( As rei (ti) , ASrei ( t2ASrei ( t n) ) ) of the wheel diameter (d(t) ) and the relative error (As rei (t) ) and a communication device (7, 7A, 7B) which sends warnings and / or error messages depending on the position of the wheel diameter (d(t) ) to a fixed limit value (d m in) to the control station (9A, 9B) of the rail vehicle (1, 2).

12. Arrangement according to claim 11, characterized in that the storage device (6) as an external storage device (6) is part of a maintenance platform which is designed to store, analyze and process operating status data of at least one rail vehicle.

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