[DESCRIPTION]
[invention Title]
MONITORING SYSTEM FOR WHEEL PROFILE DEFECT OF RAILWAY VEHICLES
[Technical Field]
The present invention relates, in general, to a system for detecting wheel profile defects in a railway vehicle, and, more particularly, to a system for monitoring whether the wheel profiles of a railway vehicle are abnormal in a non-contact manner.
[Background Art]
Generally, wheels which constitute a railway vehicle are the most important components determining safety when a railway vehicle travels, and are subjected to continuous contact load from rails.
Therefore, damage to wheel profiles, attributable to continuous and lasting contact load, generates impact load during travel, and affects the components of a bogie, on which the wheels are installed, so that the damage and derailment of the wheels are induced, thereby causing great endangerment to lives .
The causes of the damage occurring in wheels include contact load between wheels and rails, fatigue cracks
attributable to lateral load when a railway vehicle travels along a curved line, heat cracks attributable to braking heat, abrasion in the event of braking, and abnormal abrasion. Here, cracks generated in the profiles of wheels may be most critical.
Therefore, since, for the safe travel of a railway vehicle, cracks generated in the profiles of wheels must be detected, and measures, such as the repair or removal of wheels, must be taken at the time of maintenance, a device capable of detecting cracks generated in the profiles of wheels is required.
[Disclosure] [Technical Problem]
Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide a system for detecting wheel profile defects in a railway vehicle, which monitors the states of the defects of the wheel profiles in a railway vehicle in a non-contact manner, thereby improving resolution and reliability.
Another object of the present invention is to provide a system for detecting wheel profile defects in a railway vehicle, which can detect whether the wheel profiles are abnormal when the railway vehicle travels .
[Technical Solution]
In order to accomplish the above objects, the present invention provides includes magnetic field measurement means for obtaining information about a magnetic field near each wheel of a railway vehicle; and data collection means for reading the presence or absence of a defect in the wheel in a magnetic image form using the information about the magnetic field obtained by the magnetic field measurement means . Here, the magnetic field measurement means includes magnetization means for magnetizing the wheel, a magnetic lens for focusing a magnetic field on the profile of the magnetized wheel, a magnetic sensor array for converting the information about the magnetic field, focused using the magnetic lens, into electric signals, and an Analog/Digital (A/D) converter for converting the information about the magnetic field, converted into the electric signals using the magnetic sensor array, into digital signals.
Further, the magnetic sensor array is configured such that a plurality of magnetic sensors is arranged on a semiconductor wafer at predetermined regular intervals .
Further, an amplification unit for amplifying the signals of the information about the magnetic field detected by the magnetic sensor array is further included. Further, a filtering unit for removing noise from the information about the magnetic field detected by the
magnetic sensor array is further included.
Further, the magnetization means is any of an electromagnet, an induced current, a Helmholtz coil, and geomagnetism. Further, the magnetic sensor array is installed in such a way that a seating depression is formed by removing part of the upper portion of a rail with which the wheel profile comes into contact and the magnetic sensor array is embedded in the seating depression. Further, the data collection means includes a control unit for analyzing the information about the magnetic field transmitted from the magnetic field measurement means, and reading the presence or absence of a defect in a magnetic image form, a memory unit for storing and managing the information about the magnetic field transmitted from the magnetic field measurement means, and storing an analysis program for analyzing the information about the magnetic field, a display unit for displaying the magnetic images read by the control unit, and a power supply unit for supplying power.
Further, the data collection means includes an industrial computer.
[Advantageous Effects]
As described above, a system for detecting wheel profile defects in a railway vehicle according to the
present invention detects the states of cracks in wheel profiles using a non-contact-type magnetic sensor, so that the state of a wheel can be precisely determined, thereby having an advantage in that measures, such as the repair or replacement of a wheel, can be reliably taken.
Further, the abnormal state, such as defects in wheel profiles, can be detected even when a railway vehicle is traveling, so that an advantage is obtained in that it can be installed in rails which come into contact with wheels or the bogie of a railway vehicle in various ways and then operated.
[Description of Drawings]
FIG. 1 is a schematic diagram showing a system for detecting wheel profile defects in a railway vehicle according to the present invention; FIG. 2 is a detailed diagram showing the system for detecting wheel profile defects in a railway vehicle according to the present invention;
FIG. 3 is a cross-sectional view showing examples of the installation of a magnetic sensor according to the present invention;
FIG. 4 is a photograph showing materials that can be used to detect defects using the magnetic sensor employed in the present invention;
FIG. 5 shows a screen in which an analysis program for determining whether each of test specimens is abnormal
is executed according to the present invention;
FIG. 6 is a view showing plate-type test specimens in which various types of defects are induced;
FIG. 7 is a view showing magnetic images obtained from the plate-type test specimens of FIG. 6 using the system for detecting wheel profile defects in a railway vehicle according to the present invention;
FIG. 8 is a view showing the states of defects in sections of the respective test specimens based on the result of an experiment of FIG. 7; and
FIG. 9 is a graph showing a result of analysis based on the result of an experiment of FIG. 8.
[Best Mode]
Features of a system for detecting wheel profile defects in a railway vehicle according to the present invention will be understood using embodiments, which will be described in detail with reference to the attached drawings .
Here, FIG. 1 is a schematic diagram showing a system for detecting wheel profile defects in a railway vehicle according to the present invention, FIG. 2 is a detailed diagram showing the system for detecting wheel profile defects in a railway vehicle according to the present invention, FIG. 3 is a cross-sectional view showing examples of the installation of a magnetic sensor according
to the present invention, FIG. 4 is a photograph showing materials that can be used to detect defects using the magnetic sensor employed in the present invention, FIG. 5 shows a screen in which an analysis program for determining whether each of test specimens is abnormal is executed according to the present invention, FIG. 6 is a view showing plate-type test specimens in which various types of defects are induced, FIG. 7 is a view showing magnetic images obtained from the plate-type test specimens of FIG. 6 using the system for detecting wheel profile defects in a railway vehicle according to the present invention, FIG. 8 is a view showing the states of defects in sections of the respective test specimens based on the result of an experiment of FIG. 7, and FIG. 9 is a graph showing a result of analysis based on the result of an experiment of FIG. 8.
First, referring to FIGS. 1 to 3, the system for detecting wheel profile defects in a railway vehicle according to the present invention detects whether a wheel profile λla' is abnormal using a magnetic sensor 112a.
It is preferable that the system for detecting wheel profile defects in a railway vehicle use an edge area detection method, capable of sensing cracks in wheels when a railway vehicle enters a maintenance and engineering division or a railway vehicle shed, in consideration of expense and efficiency, so that whether a wheel profile is
abnormal can be detected when a railway vehicle travels slowly.
Here, a plurality of magnetic sensors 112a is attached to the upper portion of a rail 10, which comes into contact with wheels, in order to use a leakage flux detection method, which is performed in a non-contact manner, so that the system for detecting wheel profile defects in a railway vehicle can detect whether a wheel profile is abnormal, that is, can detect the state of cracks, of the wheel profile when a railway vehicle travels.
Meanwhile, such a magnetic sensor 112a can be applied to various application fields, and can detect the presence or absence of defects. The application fields thereof include the detection of defects in nickel-coated Inconel planks of a nuclear power plant, the detection of fatigue cracks in the aluminum alloy of an aging aircraft, the detection of defects in stainless steel, such as the gas pipe, the material of which is transformed, of a nuclear power plant, and the detection of defects in carbon steel used for petrochemistry, shipbuilding and iron manufacture, and a rapid transit railway.
The system for detecting wheel profile defects in a railway vehicle includes magnetic field measurement means 110 for focusing a magnetic field in the vicinity of the wheel profile Λla' of a railway vehicle using a magnetic
lens 114, and converting the focused magnetic field into electric signals using a magnetic sensor array 112, thereby obtaining quantitative magnetic filed information in order to record and analyze the distribution of magnetism, which is not visible, and includes data collection means 120 for reading the presence or absence of defects in the wheel profile λla' in the form of magnetic images using the information about the magnetic field obtained by the magnetic field measurement means 110. In the case in which the magnetic sensor array 112 is used, magnetic images having resolution able to detect cracks of 5 mm or less can be acquired when a railway vehicle travels at a speed of approximately 30 km/h.
Here, it is preferable that the magnetic sensor array 112, as shown in (a) and (b) of FIGS. 3, be installed in such a way that a seating depression x10a' is formed by removing the upper portion of the rail 10 and the magnetic sensor array 112 is embedded in the seating depression Λ10a' . In this case, the seating depression ' 10a' can be formed in the center or on one side of the upper portion of the rail, as needed.
Hereinafter, the respective components, which configure the present invention, will be described in further detail.
First, the magnetic field measurement means 110
includes magnetization means 116 for magnetizing a wheel 1, a magnetic lens 114 for focusing a magnetic field on the profile 'Ia' of the magnetized wheel 1, a magnetic sensor array 112 for converting information about the magnetic field, focused using the magnetic lens 114, into electric signals, and an Analog/Digital (A/D) converter 113 for converting the analog-type information about the magnetic field, converted into electric signals using the magnetic sensor array 112, into digital signals. Here, the magnetic field measurement means 110 further includes an amplification unit 115 for amplifying the signal of the information about the magnetic field, which is weak and is detected using the magnetic sensor array 112, at a predetermined rate, and a filtering unit 117 for performing filtering so as to remove the noise from the amplified information about the magnetic field.
Therefore, the information about the magnetic field, passed through the filtering unit 117, is digitized by the A/D converter 113. The information about the magnetic field, digitized by the magnetic field measurement means 110, is collected by the data collection means 120, and the magnetic images of the wheel profile Λla' are read and displayed based on a predetermined algorithm, so that an operator can check the magnetic images.
With the above-described configuration, a magnetic
field, based on the discontinuity of the profile vla' of the wheel 1 of the railway vehicle, which is an object to be gauged, is focused by the magnetic lens 114, converted into electric signals by the magnetic sensor array 112, transmitted to the data collection means 120, and then used as quantitative basic data so as to record and analyze the distribution of magnetism, which is not visible.
Here, an electromagnet, an induced current, a Helmholtz coil, or geomagnetism is selectively used as the magnetization means 116, depending on whether ferromagnetic metal or paramagnetic metal is used.
In particular, in order to detect and evaluate cracks in the surface of ferromagnetic metal or in the vicinity of the ferromagnetic metal, the magnetization means 116 magnetizes test specimens using a yoke-type magnetizer, focuses leakage flux, occurring due to the cracks, using the magnetic lens 114, and obtains the distribution of the leakage flux.
Meanwhile, it is known through reports on the results of recent research that the magnetic sensor 112a can detect defects and fatigue cracks in materials in which ferromagnetic materials and paramagnetic materials are composed, as shown FIG. 4, for example, nickel-coated Inconel planks of FIG. 4 (a) , the stainless steel of FIG. 4 (c) , the aluminum alloy, which is paramagnetic metal, of FIG. 4 (b) , and the carbon steel, which is ferromagnetic
material , of FIG . 4 (d) .
The magnetic sensor array 112, in which a plurality of magnetic sensors 112a is arranged, is configured such that 64 magnetic sensors 112a are arranged on a semiconductor wafer '112b' in a straight line at an interval of approximately 0.52 mm.
The magnetic sensor array 112 is configured such that the plurality of magnetic sensors 112a is densely arrayed, so that the magnetic sensor array 112 can obtain high spatial resolution, with the result that the magnetic sensor array 112 can detect even smaller crack (for example, a hole having a minimum radius of 0.25 mm) in an even larger region (for example, a region having a width of 32 mm) . The data collection means 120 reads the presence or absence of defects, such as cracks, in the wheel profile
Λla' , in the form of magnetic images using the information about the magnetic field collected by the magnetic field measurement means 110. The data collection means 120 includes a control unit 121 for analyzing the information about the magnetic field, transmitted from the magnetic field measurement means 110, based on a sequential algorithm, and reading the presence or absence of defects in the form of magnetic images, an operation unit 122 for enabling a user to input various types of control items, a display unit 123 for displaying the magnetic images read by
the control unit 121, a memory unit 124 for storing and managing the information about the magnetic field, transmitted from the magnetic field measurement means 110, and storing an analysis program for analyzing the information about the magnetic field, and a power supply unit 125 for supplying driving power.
Here, the data collection means 120 includes a general industrial computer, the display unit 123 includes a monitor, and the operation unit 122 includes a general keyboard and a mouse.
Hereinafter, a process of detecting the presence or absence of the defects in a wheel profile using the system for detecting the wheel profile defects in a railway vehicle according to the present invention will be described in detail with reference to FIGS. 1 to 3.
The magnetization means 116 of the magnetic field measurement means 110 is operated so as to magnetize a wheel and focus a magnetic field on the profile λla' of the rotating wheel 1, so that the magnetic field is converted into electric signals by the magnetic sensor array 112.
The information about the magnetic field detected by the magnetic sensor array 112 is digitized by the A/D converter 113 and is then input to the data collection means 120. Further, the collected information about the magnetic field is stored in the memory unit 124, is used to detect
the presence or absence of defects in the wheel profile through the execution of an analysis program, and is then output to the monitor, that is, the display unit 123, so that an operator can perform checking and analysis. The analysis program, as shown in FIG. 5, is executed to be output on the monitor, which constitutes the display unit 123.
Here, in FIG. 5, (a) Normal 200 illustrates the distribution of a magnetic field, and (b) dB/dx 202 and (c) dB/dy 204 illustrate the results of image processing, that is, more definitely illustrate the presence or absence of defects. Further, the (a) Normal 200, the (b) dB/dx 202, and the (c) dB/dy 204 are displayed in real time.
Further, (d) Section view 206 is a graph which is used to analyze the result of an experiment, and shows the section of the image of a magnetic field detected by the magnetic sensor 112a. Based on an example displayed in the
(d) Section view 206, the size of the depth or volume of each of the defects in the wheel profile xla' has a close relationship with the corresponding measurement value or analysis value, so that quantitative evaluation of defects is possible.
Further, when the (d) Section view 206 is displayed, the respective images of the (a) Normal 200, the (b) dB/dx 202, and (c) dB/dy 204 can be selected using (e) Selection 208. (f) Coordinate 210 displays coordinates used to obtain
the quantitative location and value in the (d) Section view 206.
Further, (g) Full Scale Output (FSO) 212 performs a function of varying the maximum value MAX and minimum value MIN of an image in order to more definitely detect defects from the images of the (a) Normal 200, the (b) 3B/3x 202, and the (c) 3B/3y 204.
Based on the above-described analysis program, as shown in FIG. 6, an experiment for defect detection is performed using flat test specimens, the size of which are predetermined, and in which various types of defects are artificially induced. As the result of the experiment, information about a magnetic field, as shown in (a) and (b) of FIG. 7, can be obtained. Here, for a defect, induced in a circular shape, in the upper portion of (a) of FIG. 7, a hole having a depth of 0.4 mm, the radius of which may be 2.5 mm, 1.5 mm, 1 mm, 0.5 mm, or 0.25 mm, can be visible. Further, in the case in which a slit-shaped defect is formed perpendicular to a magnetization direction, the defect is visualized as shown in the lower portion of (a) of FIG. 7. In the case in which the slit-shaped defect is inclined at an angle of 45 degrees relative to the magnetization direction, all defects, the length of which is 5 mm or greater, the depth of which is 0.2 mm or greater, and the width of which is 0.2 mm or greater, can be detected, as shown in the upper
portion of (b ) of FIG . 7 .
Meanwhile, in the case in which a defect is formed horizontal to the magnetization direction, the presence of the defect can be detected with some effort based on images, as shown in the lower portion of (b) of FIG. 7, but the defect cannot be precisely determined. Of course, since the fact that such a defect, that is, the defect formed horizontal to the magnetization direction, can be detected by inducing a cross magnetizer or an induced surface current has been reported, it is preferable to solve the above-described problem in this way.
FIG. 8 is a view showing the states of defects in sections of the respective test specimens, extracted from the result of the experiment, based on the execution of the analysis program of FIG. 7, that is, a graph showing the states of sections across the center of the defects in the respective images. Here, the horizontal axis indicates distance and the vertical axis indicates strength. As can be known from the graph, the strength of each signal varies depending on the size of a defect and the magnetization direction. Further, as shown in Fig. 9, such variation shows a tendency to have a considerably close relationship with the cross section of the defect. Therefore, when the defects in the wheel profile xla' are detected using the system for detecting wheel profile defects in a railway vehicle according to the present invention, the location,
shape, direction, and size of the respective defects can be quantitatively evaluated.
Although the preferred embodiments of the present invention have been described, the patent rights claimed for the present invention are not limited thereto, and the patent rights claimed for the present invention encompass substantial equivalents to the embodiments of the present invention. Accordingly, it will be apparent to those skilled in the art that various modifications are possible within a range that does not depart from the scope of the technical spirit of the present invention.
[industrial Applicability]
The present invention relates, in general, to a system for detecting wheel profile defects in a railway vehicle, and, more particularly, to a system for monitoring whether the wheel profiles of a railway vehicle are abnormal in a non-contact manner.