JP2003535755A - Method and apparatus for detecting defects in circular shape of railway train wheels - Google Patents

Abstract

(57) [Summary] A movement sensor (3) is coupled to a wheel (1) of a railway train, the sensor generating a signal (M) indicative of the movement of the wheel along a vertical axis (x). The rotation sensor (6) provides a signal (S) indicating the rotation speed of the wheel (1). The movement signal (M) and the rotational speed signal (S) are correlated using the speed signal (S) to correlate both signals, and each subsequent signal corresponds to a vertical portion or time frame corresponding to one complete rotation of the wheel. It is received by an electronic processing unit (E) that divides the movement signal (M). An average of subsequent time portions of the stored motion signal over a period of time is calculated to identify defects in the actual or initial circular shape of the wheel.

Description

Detailed Description of the Invention

The present invention relates to a method and a device for detecting defects in the circular shape of railway train wheels.

The main circular defects on the rolling surface of a wheel can be summarized as follows. -The flatness of the wheel rolling surface on the rails caused by wheel locking during train movement or, more commonly, brake malfunction; -heterogeneity of the material forming the wheels. The side profile of the wheel is not circular but is, for example, egg-shaped or lobe-shaped due to the imbalanced mounting of the wheel due to.

Non-circular wheels cause vibrations, which adversely affect the performance of the axle and also damage other parts of the wheel, reducing the safety of the wheel over time.

Conventionally, the method of inspecting the wheel condition has a limitation in regular management, and at that time, an expert boarded a train to evaluate the degree of comfort. Specialization gave instructions that at least one of the eight wheels of the train had to be replaced depending on the situation, or that the sides of the wheels had to be rounded.

However, such an inspection method cannot prevent or detect the occurrence of a defect in the circular shape of the wheel in a timely manner to prevent the defect from becoming worse.

US Pat. No. 5,433,111 discloses a series of train train wheels and a device for detecting a defective condition of a track through which a train runs. The device comprises a measuring means for generating data representing the rotational speed of the wheels, data representing the movement along three orthogonal axles, one of the three axles being substantially perpendicular to the track. And a data processor that detects a defective condition of at least one wheel of the train based on the received rotational speed and movement data.

However, these known systems have the limitation that it is not possible to distinguish whether the abnormal vibration is due to the wheels, the axle bare linking, or the track or even other causes. Furthermore, the above-mentioned prior art cannot identify which wheel of the train is affected by the defect.

The present invention provides for the timely prediction and / or identification of the occurrence of a circular defect, the form of the defect and its exact location and alerting in real time, in particular which wheels of the train are affected by the defect. The purpose is to identify what is.

Another object of the present invention is to continuously monitor the operating state of the wheels to obtain real-time information on the fluctuation of the defect in a timely manner, to urgently intervene for serious damage or to detect detected damage. Depending on the criticality of the intervention, the intervention may be delayed, or it may be determined if intervention is not required, such as when an operational defect has subsided or subsided.

Yet another object of the present invention is to shorten the overall maintenance end time by optimizing maintenance so that intervention can be made only when appropriate or necessary.

The above and other objects further understood by the following description are achieved by the method defined in claim 1 which is the first aspect of the present invention.

[0012]   As another aspect of the invention, an apparatus as defined in claim 9 is provided.

[0013]   Further important features of the invention are defined in the dependent claims.

First, referring to FIG. 1, reference numeral 1 schematically represents the wheels of a railway train moving on a track 2. A movement sensor 3 for detecting the acceleration in the vertical direction x is mounted on a fixed support element 4 which is fixed to or integrally formed with an element supporting the axle of the wheel.

The device shown in FIG. 1 is known per se to a person skilled in the art and will not be described in detail here. For example, the fixed support element 4 may be a bearing axle box, or an outer cover of an axle box, or an outer fixed race of an axle bearing, or a sealing insert mounted on the race.

The movement sensor 3 comprises a piezo-accelerator, which is preferably a piezo-accelerator of a known type coupled to an amplifier incorporated in the same body containing it.

In FIG. 1 there is a flat portion 5 on the rotating periphery of the wheel, which causes vertical acceleration as detected by the movement sensor 3 when the wheel rotates and passes through the flat portion. . As a result, the movement sensor produces a signal indicating the movement of the wheel 1 along the vertical axle x.

The signal of the vertical movement is generated by removing all extraneous vibration components from the signal and maintaining the harmonic vibration content of the signal under control, ie the rotation of the wheels with non-circular sides. Preferably, the vibrations are filtered through hardware and / or software filtering means that reduce the vibration.

The wheel is equipped with a speed sensor 6 coupled to an encoder 7 that rotates at high speed with the axle, for example an impact wheel of the type normally used for detecting rotational speed. The speed sensor 6 is preferably mounted on a fixed support element and fixed to the support element of the wheel axle or is formed integrally with said support element.

The structural and operational features of the speed sensor and of the associated encoder or impact wheel (which may be any known) are not relevant to an understanding of the present invention and therefore a detailed description is provided herein. Absent. Here, since the wheel rotates at high speed together with the encoder 7 when the wheel 1 rotates, the speed sensor 6 is affected by the encoder 7.
It suffices to mention that indicates the rotational speed of the wheel and generally gives a signal with a frequency proportional to the angular speed of the wheel.

For the sake of simplicity, FIG. 1 shows an example in which the speed sensor 3 is mounted on the same element 4 that supports the movement sensor 3. Choosing to mount the sensors 3 and 6 on a common support element will give a favorable solution in certain use situations, but is clearly not an essential feature for the purpose of implementing the invention.

In a preferred embodiment, the speed sensor 6 is fixed to a fixed outer race of the bearing.

In a first embodiment, the encoder 7 has an irregular structure, eg a longer toothed structure or invisible, which serves as a reference point for a constant angular position of the wheel and corresponds to a point on the circumference of the wheel. A depression is provided. In this case, the speed sensor 6 gives a signal pulse or signal every time the wheel completely rotates.

Alternatively and according to a preferred embodiment, a speed sensor connected to the impact wheel by using as an encoder an impact wheel with a fixed number n (eg n = 80) of sectors is such that the wheel is completely It is configured to give an impact each time it rotates. The pulse emitted by the speed sensor is provided to an n-divider, and the output from the divider provides a pulse for every n-pulse received by the speed sensor.

In any case, the output speed pulse S or the signal given for every complete rotation of the wheel is supplied to an electronic processing unit E (FIG. 2) which also receives the signal M from the vertical movement sensor 3. To be done.

The electronic processing unit E uses the rotational speed signal or wheel pulses S to correlate the two signals M, S to correlate the vertical movement signal in a time section or frame corresponding to a complete rotation of the following wheel. Divide M.

The frame is stored in the electronic processing unit E or in another electronic unit connected to it, the vertical acceleration being received during one complete rotation of the wheel being reproduced on the vertical axis in FIG. Form a plurality of frames shown superimposed. This data collection will be carried out continuously over a period of time.

It is possible that an anomalous signal may be generated indicating vertical movement as the wheel passes over a locally uneven portion of the track, for example a discontinuity at the joint of the rail or a point on the rail or over a foreign object. Especially important. As a result, if they are similar to each other but not actually identical to each other, a corresponding abnormal frame that is clearly different from other frames is acquired.

Therefore, for example, every 50 frames or at selected intervals, the correlation function or exponent between all the frames obtained at the intervals is calculated periodically, and a predetermined numerical value, that is, other numerical values, is considerably calculated. It is possible to ignore frames with lower correlation values than different numbers.

By calculating the average of the remaining frames, ie similar frames, it contains only information about the circular defects of the wheels and not any non-repetitive faults due to other causes such as track anomalies. The average wavelength (FIG. 4) is obtained.

Since the only synchronized frequency is that of a complete rotation of the wheel, the final mean does not take into account stresses due to causes unrelated to the wheel, but also has a speed different from the rotation speed of the wheel. It does not take into account other stresses due to potential anomalies in the rotating parts of the shaft (eg rollers of the axle bearing). In fact, the stresses due to the other rotating parts have a frequency different from the frequency of the wheels, since they are not synchronized with the rotation of the wheels and they do not influence the final mean.

In other words, the detection of the vertical movement of the wheel in synchronism with the rotating wheel is, in the final mean, the data detected during rotation when the wheel is under non-repetitive stress, more generally Is independent of the data obtained from stresses with frequencies that differ from the wheel rotation frequency. It is clear that the data collection must be done for a sufficiently postponed period to make the abnormal frame statistically irrelevant.

As will become apparent below, the method of the invention is theoretically independent of the speed at which the train moves. However, in the test conducted by the applicant, the train is 100 km.
Good results are obtained when moving at a substantially constant speed of / h or more. To obtain the final mean waveform (FIG. 4) starting from the stored frame (FIG. 3), a number of statistical algorithms can be used, for example to calculate the exponential moving average, mean value, mean square deviation, etc.

The above data collection is carried out for all wheels of the railroad train, which makes it possible to detect the occurrence of defects, predict the initial defect state and track its progress over time, and which wheels are involved in the defect. It becomes possible to identify whether or not.

It is also possible to set the electronic processing unit E to automatically issue an alarm signal A when a predetermined threshold value for identifying an actual or initial defect state is reached or exceeded.

Further in accordance with the invention, if a velocity signal or pulse is generated at a certain angular position corresponding to an exact point on the circumference of the wheel, the frame obtained above will start corresponding to that position. Have a point. As a result, the average waveform of the wheel practically displays a polar diagram for the side of the wheel that accurately indicates the location of the defect along the circumference.

[Brief description of drawings]

The features and advantages of the present invention will become apparent from the following detailed description of embodiments, which is given by way of non-limiting example only, with reference to the accompanying drawings.

1 is a diagram schematically showing the wheels of a railway train in the context of the device according to the invention.

FIG. 2 is a block diagram showing signal generation and processing in a device according to the present invention.

3 shows a series of subsequent frames of signals representative of the vertical movement of the wheel of FIG. 1 in the time domain.

4 shows a signal obtained as a means of the subsequent frame of FIG.

─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Sema, Silvano             Italy Ai-10060 Celsenasco               Via Dante Alighieri 2 F term (reference) 2F069 AA24 AA68 AA99 BB27 GG04                       GG06 GG20 JJ17 NN17 NN26

Claims (15)

[Claims] 1. A movement sensor means (3) connected to a train train wheel (1) for generating a signal (M) indicative of the movement of the wheel along an essentially vertical axis (x). Providing step, (b) providing a rotation sensor means for supplying a signal (S) indicating the rotation speed of the wheel (1), (c) using the electronic processing device (E), the movement signal (M) and rotation Speed signal (S)
And correlating the two signals with the speed signal (S) to divide the vertical movement signal (M) in a time portion or time frame, each subsequent time corresponding to one complete wheel revolution. (D) storing the subsequent time portion of the travel signal (M), and (e) calculating an average of the subsequent time portions of the travel signal stored during a period of time, and calculating the average. A method of detecting defects in a circular shape of a railway train wheel, which comprises the steps of identifying defects in an actual or initial circular shape of a wheel based on the method. 2. The step (e) so that the time portion of the movement signal (M) containing data representing the stresses that are not repeated with respect to the rotational speed of the wheel (1) is statistically irrelevant.
2. The method of claim 1, wherein the average calculated in <tb> is calculated based on a number of subsequent time portions. 3. The step (c) comprises the step of filtering the movement signal (M) in order to remove from the movement signal (M) all vibrational components not generated by the rotation of wheels on the track. The method of claim 1, wherein 4. The method of claim 1, wherein the step (b) of generating the speed signal comprises the step of generating a single speed signal for every complete revolution of the wheel. 5. The step (b) of generating the velocity signal comprises the step of generating a number (n) of pulses per complete revolution of the wheel, and a single output for every n pulses received. The method of claim 1 comprising transmitting the pulse to an n-divider that produces a velocity signal. 6. Method according to claim 1, characterized in that the step (c) of receiving the signals (M, S) takes place in a train moving at a substantially constant speed. 7. A method as claimed in claim 1, characterized in that the step (c) of receiving the signals (M, S) is carried out in a train moving at a speed exceeding 100 km / h. 8. The step (e) is followed by the step of automatically issuing an alarm signal (A) when the average of the subsequent time portions reaches or exceeds a predetermined threshold value. The method of claim 1. 9. A movement sensor means (3), connected to the wheels (1) of a railway train, for providing a signal (M) indicative of the movement of the wheels along an axis (x) which is essentially vertical, wheels. Rotation sensor means (6) for giving a signal (S) indicating the rotation speed of (1),-Receiving the movement signal (M) and the speed signal (S),-Using the speed signal (S), Correlating both signals and dividing said vertical movement signal (M) in a time portion or time frame each of which corresponds to one complete rotation of the wheel, a plurality of subsequent times of said movement signal (M) Storing a portion, -calculating an average of the subsequent time portions of the movement signal (M) stored within a certain period of time, and-based on the average the defects in the actual or initial circular shape of the wheel. Electronic processing device (E) for identification Defect detection apparatus in circular et constituted railroad train wheel. 10. The circuit further comprises circuit filtering means for filtering the movement signal (M) in order to remove from the movement signal (M) all vibration components that are not generated by the rotation of the wheels on the track. The apparatus according to item 9. 11. Device according to claim 9, further comprising alarm means for automatically issuing an alarm signal (A) when the average of said subsequent time portions reaches or exceeds a predetermined threshold value. . 12. The movement sensor means (3) is connected to an encoder (7) which produces a single speed signal for each complete revolution of the wheel.
The device according to the item. 13. The movement sensor means (3) is connected to an encoder (7) which produces a large number (n) of pulses for every complete rotation of the wheel, and operationally with the sensor means (3). 10. The apparatus of claim 9, further comprising an n-divider that is concatenated to generate a single output rate signal each time it receives n pulses. 14. Device according to claim 9, characterized in that it comprises movement sensor means (3) and speed sensor means (6) connected to each of the railroad train wheels. 15. Device according to claim 9, characterized in that said movement sensor means (3) are mounted on an element (4) supporting the axle of the wheel.