JP2002107348A - Method and device for detecting damaged state of wheel tread - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the detection method and device of the damaged state of a wheel tread, for accurately detecting the actual damaged conditions of the wheel tread, without depending on someone else's help. SOLUTION: Shocking vibrations are generated, when a railroad car drives is detected by a detection device 2 to detect the damaged state of the wheel tread. In a first invention, when the detection signal is an acceleration signal, a frequency characteristic correction curve for emphasizing low frequency is used for correction. When the detection signal is an acceleration signal or a displacement signal, a frequency characteristic correction curve, that is equivalent to the speed signal or the displacement signal, is used for correction, and the damaged state of the wheel tread is detected, based on the calculation value. In a second invention, either of the effective value of the detection signal, the average value of the absolute value, and the root-mean-square value is calculated, and the damaged state of the wheel tread is detected, based on the calculation value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for detecting a damaged state of a wheel tread, which can accurately detect a damaged state of a wheel tread, which causes vibration and noise of a railway vehicle.

[0002]

2. Description of the Related Art Various damages such as flats, thermal cracks, and peeling occur on wheel treads of railway vehicles. In flat, braking force is applied in a state where the frictional force between the wheel and the rail is reduced due to rainfall or the like, or the wheel slides on the rail due to excessive braking force such as sudden braking etc. It is a flat part formed by local wear.
A thermal crack is a crack generated by internal stress being concentrated by repeatedly heating and cooling the plastic region due to frictional heat of the wheel with the brake shoe. In the peeling, a flat or a thermal crack develops, and adjacent cracks overlap to peel off the surface layer.

[0003] Since the above-mentioned damage to the wheel treads causes problems in various points such as safety, ride comfort, noise, track maintenance, etc., a vehicle inspection staff grasps the damage condition of the wheel treads of all the vehicles and performs wheel rolling. It is necessary to take measures such as. For this reason, crews and employees have conventionally been required to report and inspect daily (train inspection, monthly inspection)
The results of the visual inspection at the site were managed by writing them in a ledger. These human eye and ear tests, which have been performed for many years, are in themselves reliable. However, the method of relying on manpower requires a lot of trouble,
There was a big problem that it was difficult to grasp the situation of all vehicles as a whole.

[0004] In order to escape from such a manual method, a vibration accelerometer is installed on a rail, a sleeper, or the like to detect the vibration during the running of the vehicle. Attempts have been made to evaluate. However, the acceleration peak value detection method has many practical problems as follows, and has a poor reliability.

[0005] First, a railroad track composed of rails, sleepers, crushed stones and the like is a tertiary or quaternary resonance system, and the rails vibrate complicatedly when passing through the vehicle. Therefore, when the vibration acceleration of the rail is detected, an impact waveform (generally 100 Hz to 100 Hz) generated due to damage of the wheel tread hitting the rail.
A waveform in which the resonance waveform of the rail (about 1 kHz) is superimposed on 1 kHz) is detected, and the degree of damage is not directly reflected on the acceleration peak value. For example, the upper and lower graphs of FIG. 18 are graphs showing the waveforms of the detected acceleration, but the acceleration peak values are significantly different even though the actual degree of damage is almost the same.

[0006] Second, a single lesion may exhibit relatively large acceleration peaks, even if small. On the other hand, if the damage is continuous, the acceleration peak value is not likely to have a large value corresponding thereto, so that the continuous damage is not evaluated. As described above, the acceleration peak value is greatly affected by the shape, and it is difficult to correctly indicate the magnitude.

[0007] Third, although the damage that produces a heavy bass sound (low-frequency sound) that resounds the belly tends to be larger than the damage that produces a high sound, the acceleration peak value is not so large. Often they do not show large values. That is, the degree of damage is not correctly reflected in the acceleration peak value.

[0008] Fourth, if there is a convex scratch on the wheel tread surface, the rail is directly impacted, so that although the damage itself is small, it tends to show a very large acceleration peak value.

Fifth, if the corner of the damaged portion is rounded, the acceleration peak value will decrease.

Sixth, when the brake is of a type in which the brake is brought into contact with the wheel tread and a brake having a high aggressiveness against the wheel tread such as a cast iron brake is used, a brake such as a synthetic brake is used. Since the surface roughness of the tread is larger than when a brake shoe having a low aggressiveness to the wheel tread is used, both running noise and vibration increase even though there is no damage, and appear in the acceleration peak value. For example, FIG. 19 shows an example.

As described above, the conventionally known method for detecting a damaged state based on an acceleration peak value is liable to be influenced by factors different from the actual damaged state of the wheel tread, and has many problems in practicality. FIG. 20 summarizes the actual measurement values of a train running at about 75 km / h in the applicant company as a graph in which the abscissa represents the auditory judgment value obtained by judging the degree of damage by hearing and the ordinate represents the acceleration peak value. Things. It has been confirmed by years of experience that the auditory judgment value matches well with the actual damage state. In the case of this graph, the correlation coefficient between the acceleration peak value and the auditory judgment value is only 0.69. Particularly, in a region where the auditory judgment value is large, the variation is large, and in the damage state detection method based on the acceleration peak value,
It can be seen that not only can the damage be overestimated or underestimated, but serious damage can be overlooked.

[0012]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems and eliminates the effects of rail resonance, fine projections, tread surface roughness, and the like, and further damages and continuous damages. The present invention has been made to provide a method and an apparatus for detecting a damaged state of a wheel tread surface, which can accurately detect an actual damage state of a wheel tread surface without relying on humans while correctly evaluating the condition.

[0013]

Means for Solving the Problems According to the invention of claim 1 made to solve the above-mentioned problems, a detection device installed on or near a railroad track detects a shock generated when a railroad vehicle travels. This is a method of detecting a damaged state of a wheel tread contacting with a rail by detecting an excessive vibration, and when the detection signal is an acceleration signal, correcting the frequency using a frequency characteristic correction curve that emphasizes a low frequency. If the detection signal is a speed signal or a displacement signal, the signal is corrected using a frequency characteristic correction curve equivalent to the frequency characteristic correction curve for the acceleration signal, and based on the corrected signal waveform, the damage state of the wheel tread surface is corrected. Is detected.

According to a second aspect of the present invention, there is provided a detecting device installed on or near a railway track to detect shocking vibration generated when a railway vehicle travels. A method for detecting a damaged state of a wheel tread contacting the rail, wherein the effective value of the detection signal, the average value of the absolute value, or the root mean square value is calculated, and the wheel tread of the wheel tread is calculated based on the calculated value. It is characterized in that a damaged state is detected.

According to a third aspect of the present invention, there is provided a combination of the first and second aspects of the present invention, wherein a detecting device installed on or near a railroad track generates an impact shock generated when a railroad vehicle travels. This is a method of detecting a damaged state of a wheel tread contacting with a rail by detecting an excessive vibration, and when the detection signal is an acceleration signal, correcting the frequency using a frequency characteristic correction curve that emphasizes a low frequency. If the detection signal is a velocity signal or a displacement signal, it is corrected using a frequency characteristic correction curve equivalent to the frequency characteristic correction curve for an acceleration signal, and the average value of the effective value and absolute value of the correction signal , A root mean square value, and a damage state of the wheel tread is detected based on the calculated value.

According to a fourth aspect of the present invention, there is provided an apparatus for implementing the first aspect of the present invention, which is installed on or near a railroad track and detects shocking vibration generated when a railroad vehicle travels. A detection device, and a processing device that processes the detection signal input from the detection device. The processing device uses a frequency characteristic correction curve that emphasizes the low frequency when the detection signal is an acceleration signal. Means for correcting using a frequency characteristic correction curve equivalent to a frequency characteristic correction curve for an acceleration signal when the detection signal is a speed signal or a displacement signal, and a wheel based on the corrected signal waveform. Means for detecting the degree of damage to the tread surface.

According to a fifth aspect of the present invention, there is provided an apparatus for implementing the second aspect of the invention, which is installed on or near a railroad track and detects shocking vibration generated when a railroad vehicle travels. And a processing device for processing the detection signal input from the detection device.
Means for calculating any one of an effective value, an average of absolute values, and a root-mean-square value of the detection signal, and means for detecting a degree of damage of the wheel tread based on the calculated value. It is.

According to a sixth aspect of the present invention, there is provided an apparatus for implementing the third aspect of the present invention, which is installed on or near a railroad track and detects shocking vibration generated when a railroad vehicle travels. And a processing device for processing the detection signal input from the detection device.
When the detection signal is an acceleration signal, correction is performed using a frequency characteristic correction curve that emphasizes low-frequency components, and when the detection signal is a speed signal or a displacement signal, a frequency characteristic correction curve for an acceleration signal is used. Means for correcting using an equivalent frequency characteristic correction curve, means for calculating any of the effective value of the correction signal, the average value of the absolute value, and the root mean square value;
Means for detecting the degree of damage to the wheel treads based on the calculated value.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below. In FIG. 1, reference numeral 1 denotes a railroad track composed of rails, sleepers and the like, and reference numeral 2 denotes a detection device mounted on or near the track 1. It is preferable to use the track 1 for business operation as it is, and to select a section on which the railcar travels at a substantially constant speed. However, it goes without saying that a special track 1 for inspection may be used.
In this embodiment, three acceleration detectors are fixed to each rail as the detection device 2 to detect the rail vibration, but the shock vibration generated when the railway vehicle travels on the track 1 is detected. Can be used as long as it can detect the following.

That is, in addition to the acceleration detector, a speed detector, a displacement detector, and the like can be used as the vibration detecting device. Since acceleration, velocity, and displacement can be mutually converted by differentiation or integration, they are substantially equivalent as detection means.

In addition, a car number detector 3 and a wheel detector 4 are provided on or near the track 1 so that it is possible to specify which signal of the railway vehicle the signal waveform detected by the detector 2 is based on. So that In this embodiment, four wheel detectors 4 are arranged in correspondence with the three detection devices 2, and the detection devices 2 that take out signals as the wheels move are sequentially switched.

The detection signal detected by the detection device 2 is:
The signal is amplified by the signal amplification circuit 5, noise is removed by the analog filter circuit 6, converted to a digital signal by the A / D conversion circuit 7, and input to the wheel extraction circuit 8. On the other hand, the signal from the wheel detector 4 is also transmitted to the digital input circuit 12.
Is entered via The wheel extraction circuit 8 separates and combines the input detection signal into a detection signal for each wheel.

The vibration waveform of the acceleration obtained from the wheel extracting circuit 8 is, for example, as shown in FIG. 2. In the conventional detection method using the acceleration peak value, this waveform is used as it is. However, in the present invention, the above-mentioned drawback of the acceleration peak value detection method is solved by correcting the detection signal using the frequency characteristic correction curve that emphasizes the low frequency in the frequency characteristic correction circuit 9. When the detection signal is an acceleration signal, the frequency characteristic correction curve is, for example, as shown in FIG.

The characteristic of this frequency characteristic correction curve is approximately 1 k
Not only cuts frequencies above 1 Hz, but also
The following part is gradually emphasized toward a low frequency of about 100 Hz. In other words, the signal is attenuated toward higher frequencies and emphasized toward lower frequencies. In FIG. 3, the frequency characteristic correction curve is substantially linear in a frequency range of approximately 100 Hz to 1 kHz, but it is not necessarily required to be linear and may be an appropriate curve.

By adopting such a frequency characteristic correction curve, a high frequency region (about 1 kHz or more) caused by the surface roughness of the wheel tread is attenuated or cut, and a frequency of approximately 100 Hz or more caused by damage to the wheel tread. The frequency region of 1 kHz is emphasized toward lower frequency bands. A major feature of the present invention is that a frequency characteristic correction curve that emphasizes a lower frequency is used in this manner, and a large damage or a damage that generates a heavy bass sound (low-frequency sound) that affects the belly is emphasized. On the other hand, since it is attenuated toward higher frequencies,
A signal due to a small bump or the like is attenuated, and a signal due to the resonance of the superimposed rail (around 1 kHz) is greatly attenuated or cut. Further, when the traveling speed of the vehicle decreases, the detection signal such as acceleration tends to shift to a lower frequency side and decrease. However, by using a frequency characteristic correction curve that emphasizes the lower frequency band, the traveling speed can be reduced. The effects of On the other hand, several tens of hours caused by elastic deformation of the rail due to wheel load
The vibration below z may be cut or attenuated using a frequency characteristic correction curve as shown in FIG. 4, but if the detection signal is an acceleration signal, the low frequency is attenuated originally. There is no practical problem with using any of the frequency characteristic correction curves of FIGS.

It is preferable to use a frequency characteristic correction curve as shown in FIG. 5 when the detection signal is a vibration velocity, and to use a frequency characteristic correction curve as shown in FIG. 6 when the detection signal is a vibration displacement. Preferably, a curve is used. As described above, acceleration, velocity, and displacement can be freely converted by differentiation and integration with each other, and are substantially equivalent as detection signals. Therefore, when the detection signal is a speed signal or a displacement signal, an equivalent frequency obtained by mathematically converting the frequency characteristic correction curve for the acceleration signal as shown in FIGS. If the characteristic correction curve is used, processing can be performed in the same manner as when the detection signal is an acceleration signal. The vertical axis in FIGS. 3 to 6 indicates the input / output amplitude ratio. In the present invention, the shape of these frequency characteristic correction curves is important, and it goes without saying that the value on the vertical axis may be set to a multiple of a constant or a fraction of a constant.

As described above, when the detection signal shown in FIG. 2 is corrected by the frequency characteristic correction circuit 9 using the frequency characteristic correction curve for emphasizing the low frequency, the corrected signal waveform shown in FIG. 7 is obtained. When the signal waveform of FIG. 2 is compared with the signal waveform of FIG. 7, not only the high frequency is cut off, but the portions marked with B and C are attenuated compared with the portion marked with A. I have.

The causes of the signal waveforms of A, B, and C are as follows:
This is the damage shown in FIGS. 8, 9 and 10 present at three locations on the same wheel. As shown, the damage shown in FIG. 8 is the largest, and the damage shown in FIGS. 9 and 10 is considerably smaller than that, but the difference depending on the magnitude of the damage is not clear in the detection signal shown in FIG. In comparison with this, it can be seen that the corrected signal waveform shown in FIG. 7 emphasizes the signal waveform of A and matches well with the actual damage state.

The detection signal corrected by the frequency characteristic correction circuit 9 in this manner is read by the maximum value or peak value detection circuit 10 shown in FIG. 1 and combined with the vehicle signal from the vehicle signal detector 3. Is output as data of the damaged state.

FIG. 11 shows the measured values of the applicant company, the abscissa represents the values obtained by auditory judgment of the degree of damage, and the ordinate represents the acceleration peak values corrected using the frequency characteristic correction curve shown in FIG. This is shown as a graph taken. The original measured values are the same as those shown in FIG. As described above, the corrected acceleration peak value obtained by the method of the present invention has a correlation coefficient with the auditory judgment value greatly increased from the conventional 0.69 to 0.81, and entered a region of strong correlation. You can see that.

In the first and fourth aspects of the present invention described above,
When the detection signal is an acceleration signal, correction is performed using a frequency characteristic correction curve that emphasizes low-frequency components, and when the detection signal is a speed signal or a displacement signal, a frequency characteristic correction curve for an acceleration signal is used. After correcting using the equivalent frequency characteristic correction curve, the damage state of the wheel tread was detected based on the corrected signal waveform. On the other hand, according to the second and fifth aspects of the present invention, as shown in FIG. 12, a detection signal is input to, for example, an effective value calculating circuit 11 to calculate an effective value of a signal waveform. The effective value means the square root of the root mean square of the waveform x. In particular, it is preferable to use an effective value (rms value) defined by Expression 1 with the observation time being T. This means a value obtained by evaluating the instantaneous value of the shock vibration in consideration of a certain time width.

[0032]

(Equation 1)

As a result, as compared to the distance width of the wheel tread corresponding to the time width to be integrated, the locally generated damage is evaluated to be small, and the continuously generated damage is evaluated to be large. The effective value is maximum when the magnitude of the damage matches the integration time span. Here, the observation time T is about 100 to
When the moving time is equivalent to 300 mm, the evaluation can be performed in consideration of the circumferential length of the continuous damage, and the actual damage state of the wheel can be accurately indicated. On the other hand, if the movement time for the entire circumference or half a circumference of the wheel is adopted as the observation time T, the degree of damage in the entire circumference or half a circumference of the wheel tread can be accurately grasped. Obviously, instead of keeping the observation time T constant, the observation time T 'calculated with the movement distance constant may be used.

FIG. 13 is a graph of an output waveform from the effective value calculating circuit 11 of FIG. The original detection signal is that shown in FIG. In FIG. 2, the difference between the signal waveforms of A, B, and C was not so clear, whereas in FIG.
The difference of C becomes clear, and the content accurately reflects the damage state shown in FIGS. Note that substantially the same result can be obtained by using any one of the average value of the absolute values and the root mean square value in addition to the effective value of the detection signal.

FIG. 14 is a graph showing the relationship between the value processed by the maximum or peak value detection circuit 10 in FIG. 12 and the auditory judgment value. The correlation coefficient in this graph is 0.8
1, which indicates a strong correlation. That is, if the damage state is detected using the effective acceleration value, more accurate detection can be performed as compared with the method using the acceleration peak value.

The third and sixth aspects of the present invention combine the above-described aspects. As shown in FIG. 15, when the detection signal is supplied to the frequency characteristic correction circuit 9 and the detection signal is an acceleration signal, the low-frequency Is corrected using a frequency characteristic correction curve that further emphasizes, and when the detection signal is a velocity signal or a displacement signal, the correction is performed using a frequency characteristic correction curve equivalent to a frequency characteristic correction curve in the case of an acceleration signal.
Further, for example, it is input to the effective value calculation circuit 11 to calculate the effective value, and detects the damage state of the wheel tread based on the output waveform. It should be noted that substantially the same result can be obtained by using any one of the average value of the absolute values and the mean square value in addition to the effective value of the detection signal.

FIG. 16 is a graph showing an output waveform from the effective value calculating circuit 11 of FIG. The difference between A, B, and C is more clear, and is in good agreement with the degree of damage in FIGS. 8, 9, and 10. Further, as compared with FIG. 13, the difference between the damaged portion and the undamaged portion is more apparent. FIG. 17 is a graph showing the relationship between the value processed by the maximum or peak value detection circuit 10 in FIG. 15 and the auditory judgment value. The correlation coefficient in this graph is 0.86, indicating a stronger correlation than in FIGS. In particular, the variation is remarkably reduced in a range where the auditory judgment value is larger than the middle level, and it can be seen that the damage state can be accurately detected.

In the above-described embodiment, the processing device is described as a combination of a plurality of circuits. However, the processing device according to claims 4 to 6 may be constituted by software using a computer or the like. Not even.

[0039]

The effects of the present invention described above are summarized as follows. First, according to the first and fourth aspects of the present invention, when the detection signal is an acceleration signal, correction is performed using a frequency characteristic correction curve that emphasizes low-frequency components, and when the detection signal is a speed signal or a displacement signal. Correction using a frequency characteristic correction curve equivalent to the frequency characteristic correction curve for the acceleration signal, and detecting the damage state of the wheel tread based on the calculated value, to realize the resonance of the rail and the surface roughness of the wheel tread. Therefore, it is possible to attenuate or cut the influence such as vibration caused by the vibration. Also, a signal due to a large damage that generates a heavy bass (low-frequency sound) is emphasized, and a signal due to a small damage is attenuated, so that an accurate evaluation in proportion to the magnitude of the damage can be performed. Further, the influence of the traveling speed of the vehicle is reduced. In this way, the conventional acceleration peak value detection method was improved in that the effect of the resonance of the rails and the shape of the damage to the wheel tread was large, and the magnitude of the damage to the wheel tread was reliably captured, and the magnitude of the actual damage was improved. Accuracy can be evaluated without relying on humans.

According to the second and fifth aspects of the present invention, any one of the effective value, the average of the absolute values, and the root-mean-square value of the detection signal is calculated, and the damage state of the wheel tread is detected based on the calculated value. By doing so, the evaluation can be made in consideration of the circumferential length. As a result, locally occurring small damage is evaluated as small, and continuous or large damage is evaluated as large, so that the degree of damage can be reliably captured and the actual size of the damage can be manually determined. It is possible to evaluate accurately without relying on.

Further, the inventions of claims 3 and 6 have the advantages of the above two inventions, and it is possible to accurately detect the actual damage state. According to these inventions, it is possible to automatically detect the damage status of all wheels of all vehicles traveling on the track on which the detection device is installed,
It can greatly contribute to various aspects such as the safety of railway vehicles, ride comfort, noise, track maintenance, etc.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a vibration waveform diagram of a detection signal.

FIG. 3 is a frequency characteristic correction curve when a detection signal is a vibration acceleration.

FIG. 4 is a modified example of the frequency characteristic correction curve when the detection signal is a vibration acceleration.

FIG. 5 is a frequency characteristic correction curve when a detection signal is a vibration speed.

FIG. 6 is a frequency characteristic correction curve when a detection signal is a vibration displacement.

FIG. 7 is a signal waveform diagram corrected using the frequency characteristic correction curve of FIG. 3;

FIG. 8 is a perspective view showing damage to a wheel tread surface which is a cause of the signal waveform A.

FIG. 9 is a perspective view showing damage to a wheel tread surface which causes a signal waveform of B.

FIG. 10 is a perspective view showing damage to a wheel tread surface which causes a signal waveform of C.

11 is a graph showing a relationship between a value processed by a maximum value or peak value detection circuit in FIG. 1 and an auditory judgment value.

FIG. 12 is a block diagram showing an embodiment of the second and fifth aspects of the present invention.

13 is an output waveform diagram from the effective value calculation circuit of FIG.

14 is a graph showing a relationship between a value processed by the maximum value or peak value detection circuit in FIG. 12 and an auditory judgment value.

FIG. 15 is a block diagram showing an embodiment of the third and sixth aspects of the present invention.

16 is an output waveform diagram from the effective value calculation circuit of FIG.

17 is a graph showing a relationship between a value processed by the maximum value or peak value detection circuit in FIG. 15 and an auditory judgment value.

FIG. 18 is an acceleration waveform diagram resulting from damage to a wheel tread.

FIG. 19 is an acceleration waveform diagram resulting from the surface roughness of the wheel tread.

FIG. 20 is a graph showing a relationship between an acceleration peak value and a hearing determination value according to a conventional method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Track 2 Detection device 3 Vehicle number detector 4 Wheel detector 5 Signal amplification circuit 6 Analog filter circuit 7 A / D conversion circuit 8 Wheel extraction circuit 9 Frequency characteristic correction circuit 10 Maximum or peak value detection circuit 11 Effective value calculation circuit 12 Digital input circuit

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2G047 AA07 AC05 AC08 BC04 BC07 EA10 EA11 EA19 GG09 GG24 GG38 GG41

Claims (6)

[Claims] 1. A method of detecting a damage state of a wheel tread contacting a rail by detecting a shocking vibration generated when a railroad vehicle travels by a detection device installed on or near a railroad track. If the detection signal is an acceleration signal, it is corrected by using a frequency characteristic correction curve that emphasizes the low frequency, and if the detection signal is a speed signal or a displacement signal, the frequency characteristic of the acceleration signal is corrected. After correcting using the frequency characteristic correction curve equivalent to the correction curve,
A method for detecting a damaged state of a wheel tread, comprising detecting a damaged state of a wheel tread based on a corrected signal waveform. 2. A method for detecting a damage state of a wheel tread contacting a rail by detecting a shocking vibration generated when the railroad vehicle travels by a detection device installed on or near a railroad track. Calculating the effective value, the average of the absolute values, or the root-mean-square value of the detection signal, and detecting the damage state of the wheel tread based on the calculated value; Method. 3. A method for detecting a damaging state of a wheel tread contacting a rail by detecting a shocking vibration generated when the railroad vehicle travels by a detecting device installed on or near a railroad track. If the detection signal is an acceleration signal, it is corrected by using a frequency characteristic correction curve that emphasizes the low frequency, and if the detection signal is a speed signal or a displacement signal, the frequency characteristic of the acceleration signal is corrected. After correcting using the frequency characteristic correction curve equivalent to the correction curve, further calculate any of the effective value, the average value of the absolute value, and the root mean square value of the correction signal, and based on the calculated value, damage the wheel tread surface. A method for detecting a damaged state of a wheel tread, wherein the state is detected. 4. Installed on or near a railway track,
A detection device for detecting a shocking vibration generated when a railway vehicle travels, and a processing device for processing a detection signal input from the detection device, wherein the detection signal is an acceleration signal If the detection signal is a speed signal or a displacement signal, a correction is made using a frequency characteristic correction curve that further emphasizes the low frequency, and a frequency characteristic correction curve equivalent to the frequency characteristic correction curve for the acceleration signal. And a means for detecting a degree of damage to the wheel tread based on the corrected signal waveform. 5. Installed on or near a railway track,
It comprises a detection device for detecting shocking vibration generated when a railway vehicle travels, and a processing device for processing a detection signal input from the detection device. An apparatus for detecting a damaged state of a wheel tread, comprising: means for calculating either an average value or a root-mean-square value; and means for detecting a degree of damage of a wheel tread based on the calculated value. 6. A detecting device which is installed on or near a railroad track and detects a shocking vibration generated when a railway vehicle travels, and a processing device which processes a detection signal inputted from the detecting device. This processing device performs correction using a frequency characteristic correction curve that emphasizes low frequency when the detection signal is an acceleration signal, and calculates the acceleration signal when the detection signal is a speed signal or a displacement signal. Means for correcting using a frequency characteristic correction curve equivalent to the frequency characteristic correction curve in the case of, a means for calculating any one of an effective value, an average of absolute values, and a root mean square value of the correction signal, and the calculated value Means for detecting the degree of damage of the wheel tread based on the condition of the wheel tread.