KR100799334B1 - Crack detection apparatus in press fit railway axle - Google Patents

Abstract

A crack detection apparatus in a press-fit railway axle is provided to precisely detect surface cracks with an axle and a wheel assembled by rotating an outer peripheral surface of the axle by 0~360°. A crack detection apparatus in a press-fit railway axle(100) comprises a shelf(200), a crack detection sensor(220), a data collecting unit, a display unit, a first motor(210), and a transfer jig(230). The shelf, having a chuck(212) and an axle support-fixing tool(214), rotatably supports the press-fit railway axle. The crack detection sensor which senses potential differences by focusing induced current at a portion where the wheel is press-fitted to the axle, comprises a housing curved to make contact with the surface of the axle, a drop line inducing the induced current on the surface of the axle by receiving AC current within the housing, and two transducers for measuring potential differences on the surface of the axle where the current is induced. The data collecting unit discriminates cracks by using potential differences detected by the crack detection sensor. The display unit shows the crack data collected by the data collecting unit. The first motor provides torque to allow the axle to rotate by 0~360° around a center shaft. The transfer jig moves the crack detection sensor to make contact with the surface of the axle.

Description

Crack detection apparatus in press fit Railway Axle}

1 is a view showing for explaining the principle of the concentrated induction AC potential (ICFPD) method applied to the flaw detection device of the railroad vehicle axle indentation according to the present invention,

Figure 2 is a cross-sectional view of the axle injection portion according to the present invention,

Figure 3 is a view showing a flaw detection apparatus for a rail vehicle axle pressing portion according to the present invention,

4 is a view showing for explaining the principle of the defect detection sensor according to the present invention,

5 is a control block diagram of a flaw detection apparatus for a railway vehicle axle pressurized portion according to the present invention.

*** Explanation of symbols for main parts of drawing ***

10: guide line 11,11 ': transducer terminal

100: axle press area 102: axle

104: wheel 200: shelf

210: first motor 212: chuck

214: axle support fixture 220: defect detection sensor

230: transfer jig 240: data collection means

242: control unit 244: memory unit

250: display means 260: axial feed means

270: vertical transfer means 280: power supply means

290: operation panel

The present invention relates to a fault flaw detection device of a railway vehicle axle pressurization site, and more specifically, a railroad that can detect a defect degree of the axle pressurization site in a state where the axle and the wheel are coupled by using the concentrated induction alternating current potential vehicle method. The present invention relates to a flaw detection device for a vehicle axle press-fitting part.

The wheelset of a railroad car is one of the most important elements of a railroad car to secure driving safety as a basic component for driving a railroad car by integrating a wheel into an axle. Such damage to the wheelset may cause a major accident due to the nature of the railroad carrying a large amount of passengers and cargo, it is essential to inspect the axle and wheels constituting the wheelset.

In particular, it is necessary to precisely inspect the fatigue crack starting from the pressing part of the axle in which the wheel is pressurized. In this case, a crack detection method using ultrasonic waves is used as a method for inspecting a defect due to fatigue cracking. However, this method of ultrasonic detection can detect open cracks, but not close cracks, and it is impossible to detect side surfaces when detecting semi-elliptic cracks and to handle noise echoes. Have.

Meanwhile, in the early 1990s, Alternating Current Potential Drop (ACPD) was developed by Dover et al. To detect the surface defects of the workpiece with high sensitivity and to continuously detect the prediction of its shape and the progress of cracking. . This method takes advantage of the skin depth that a constant current flows uniformly near the surface when a constant current AC power is supplied to the workpiece.

Therefore, if a defect exists on the surface of the workpiece, the current flows along the plane of the defect, and the surface defect is detected because the path of the current flow changes by the depth of the defect. However, when ACPD is used, the current distribution of the surface due to the skin effect changes according to the distance of the supply terminal, and there is an error in the measured value due to the grounding problem of the contact point of the power supply terminal and contamination of the measurement surface. There is a problem that occurs when the application of the AC potential method of the conventional method to the axle indentation portion of the railway vehicle as it is, there is a problem that is less reliable.

Accordingly, the present invention has been made to solve the above problems, the object of which is to accurately detect the degree of defects even when the axle and the wheels are not separated when detecting a defect of the axle indentation portion of the axle and the wheel combined state. The present invention provides a flaw detection device for axle indentation of a rolling stock.

Another object of the present invention is to provide a defect flaw detection apparatus for a railway vehicle axle indentation portion that can closely inspect the degree of defects on the surface while rotating the outer peripheral surface of the axle in the range of 0 to 360 °.

The present invention for this purpose is a shelf for rotatably supporting an axle in a state in which the wheel is pressed, a defect detection sensor for detecting a potential difference by inducing a concentrated induction current to the axle indentation portion in which the wheel is pressed into the axle, and the The basic feature is that the data collection means for determining whether there is a defect using the potential difference (ΔV) detected through the defect detection sensor, and a display means for displaying the defect data collected by the data collection means.

Here, the shelf is provided with a chuck and an axle support fixture for supporting the axle to rotate freely, the axle is further provided with a first motor that provides a constant rotational force to be able to rotate 0 ~ 360 ° about the central axis It is characterized by.

The defect detection sensor may include a housing in which the contact surface is curved to be in close contact with the surface of the axle, an induction line that receives an alternating current into the housing to induce an induction current on the surface of the axle, and the induction current. Is characterized by consisting of two transducer terminals for measuring the potential difference on the surface of the induced axle.

On the other hand, the guide line has a length of 40mm, the probe terminal is characterized in that the two intervals of 5mm.

And a transfer jig for transferring the defect detection sensor to be in contact with the surface of the axle.

In addition, the transfer jig comprises an axial transfer means for controlling the defect detection sensor to move in the axial direction of the axle, and a vertical transfer means for contacting the defect detection sensor to the surface of the axle. It is done.

On the other hand, the axial transfer means is installed on one side of the body which is fixed to the shelf and the first pinion is meshed with the second motor and the first pinion provided on the motor shaft, the length of the axle when the first pinion rotates And a first rack member moved forward and backward in the direction.

In addition, the vertical transfer means is installed at the end of the first rack member and the second pinion is meshed with the third pin and the second pinion provided in the motor shaft so that when the second pinion rotates in the direction of the center of the axle It is vertically moved and its end is characterized by consisting of a second rack member to which the defect detection sensor is fixed.

Hereinafter, with reference to the accompanying drawings of the flaw detection device of the railroad vehicle axle compression portion according to the present invention will be understood by the embodiments described in detail below.

1 is a view for explaining the principle of the concentrated induction AC potential method (ICFPD) applied to the flaw detection device of the railway vehicle axle indentation according to the present invention, Figure 2 is a view of the axle indentation in accordance with the present invention 3 is a view illustrating a defect flaw detection apparatus for a railroad vehicle axle press-fitting portion according to the present invention, FIG. 4 is a view illustrating the principle of a defect detection sensor according to the present invention, and FIG. Fig. 1 is a control block diagram of a defect flaw detector at the rail vehicle axle pressurized portion according to the present invention.

The present invention detects defects in the axle indentation region by using induced current focus potential drops (ICFPD).

As shown in FIG. 1, the ICF is a method of concentrating a measurement current in a flaw detection area in order to solve a problem of a constant current distribution between supply terminals, among the problems of the ACPD. The measurement principle of the ICFPD is that when the AC current I is supplied to one induction line 10, a magnetic field H is formed at right angles to the current direction around the induction line 10. .

In this case, the magnetic field (H) is changed over time in the same manner as the frequency of the current (I) to induce a current (I ') to the measurement object 20 to generate an electromotive force (EMF), the induction The current I 'flows concentrated under the induction line 10 to a larger value than other regions.

On the other hand, the induction current (I ') flows in the opposite direction to the power supply, but has the same skin effect as the power supply (skin effect). The concentrated induction current I 'flows along the defect surface 21 of the measurement object 20, and the change according to the defect can obtain information on the defect by measuring the potential difference ΔV using the current as a measuring terminal. have.

Therefore, since this method induces the current I 'concentrated by the induction line 10, the current distribution is constant compared to the AC potential difference method ACDC in the measurement area, thereby solving the contact problem of the power supply terminal.

)는 다음과 같은 식(1)에 의해 유도되고,At this time, the depth of the defect surface 21 (

) Is derived by the following equation (1),

---(1)

---(One)

The potential difference ΔV is derived by the following equation (2).

---(2)

---(2)

Here, "μ" in the formula (1) is the permeability (H / m), "σ" is the conductivity (1 / Ω.m), "f" is the frequency (Hz), "ΔV" in the formula (2) "I" is the potential difference (V), "I '" is the induction current (A), "ρ" is the resistivity (Ω.m), "b" is the length of the defect face (m), and "j" is the current density (A). / m2), "l " is the touch distance m for measuring the potential difference, and " S "

On the other hand, Figure 2 is a view showing the axle pressing portion 100 of the railroad vehicle according to the present invention, typically press-fitting the center through portion of the wheel 104 to both ends of the axle 102 in the interference fit type. On the outer surface of the axle 102 and the inner surface of the wheel 104, minute cracks are generated at the press-in portion 100, and the heavy load repeatedly acts as the railroad vehicle moves. At the beginning of microcracks, such cracks continue to expand as fatigue occurs due to cyclic loading.

Defect flaw detection device of the railway vehicle axle indentation portion used to detect the crack of the railway vehicle axle indentation portion according to the present invention, according to Figures 3 to 5, the axle 102 in the state where the wheel 104 is pressed Both ends of the shelf 200 is rotatably supported on the top, and the first motor 210 is provided on the shelf 200 to provide a constant rotational force so that the axle 102 can rotate 0 ~ 360 ° about the axis ), A defect detection sensor 220 for inducing a concentrated induction current to the axle indentation region 100 in which the wheel 104 is pressed into the axle 102 and detecting a potential difference, and the defect detection sensor ( Data for judging defects using the transfer jig 230 for transferring the 220 to be in contact with the surface of the axle 102 and the potential difference ΔV detected through the defect detection sensor 220. Collecting means 240, collected by the data collecting means 240 Comprises a display unit 250 that displays that data.

Hereinafter, each component will be described in more detail.

First, the shelf 200 supports the axle 102 on both sides thereof and fixes one end of the axle 102 to the chuck 212 so as to be free to rotate, between the wheel 104 and the wheel 104. Is provided with an axle support fixture 214 that supports and secures any point of the axle 102. At this time, the axle support fixture 214 is fixed to the axle (102) while supporting the configuration is provided with a bearing (not shown) fixed to the shelf 200 so that the axle (102) can rotate smoothly Get drunk. Of course, the axle support 214 can be modified in various ways.

On the other hand, one end of the axle 102 is fixed to the chuck 212 is provided with the rotational force of the first motor 210 to rotate at a constant speed, the first motor 210 is rotated at the rotation angle In order to accurately calculate, a conventional servomotor equipped with an encoder is used. Accordingly, the encoder detects the amount of rotation of the rotating motor shaft by receiving a control signal and transmits it to the data collecting means 240 to clearly detect the flaw detection position.

In addition, the defect detection sensor 220 has two probe terminals (11, 11 ') to increase the degree of flaw detection inside the housing 221 is formed such that the contact surface (221a) is bent in close contact with the surface of the axle (102). The distance between the wires is 5 mm, the length of the induction line 10 is 40 mm, and the test condition is the optimum measurement result at the frequency of 3 kHz and 70 dB as a result of defect inspection while varying the frequency. The current I injected into the induction line 10 uses an AC current of 2.0 A. At this time, when the distance between the probe terminals (11, 11 ') is 5mm, the surface defects of the axle 102, which is the test body, can detect defects up to a surface defect depth of 2.0mm.

In addition, the transfer jig 230 has an axial transfer means 260 for controlling the defect detection sensor 220 to move in the axial direction of the axle 102, and the defect detection sensor 220 with the axle ( And vertical transfer means 270 for contacting the surface of 102.

In this case, the axial transfer means 260 is installed on one side of the body 260a fixed to the shelf 200 so that the first pinion 262 is provided on the motor shaft and the first motor 261 and the first motor. The first pinion 262 is engaged with the pinion 262, and the first pinion 262 is formed of a first rack member 264, which is moved forward and backward in the longitudinal direction of the axle 102, and the vertical transfer means 270 is the first The second pinion 272 rotates when the second pinion 272 meshes with the third motor 271 and the second pinion 272 provided at the end of the first rack member 264 and the second pinion 272 is provided on the motor shaft. The second rack member 274 is vertically moved in the center direction of the axle 102 and the defect detection sensor 220 is fixed at an end thereof.

In addition, the data collecting means 240, which is supplied with the power of the power supply means 280 and is operated, is initialized when an operation signal is input from the operation panel 290 for various inputs such as a switch to control and monitor the system. A control unit 242 and a memory unit 244 storing setting data are provided to control the first to third motors 210, 261 and 271, and the encoder of the first motor 210 when the axle 102 rotates. Received the amount of rotation input from to determine how much the potential difference (ΔV) occurred at which position and based on this to determine whether the defect.

Such defect data of the axle pressing portion 100 is displayed through a display means 250 such as an LCD.

3 to 5 will be described in detail the operation example of the defect flaw detection device of the railroad vehicle axle pressing portion according to the present invention.

First, one end of the axle 102 in the state in which the wheel 104 is press-fitted is fixed to the chuck 212 of the shelf 200, and one point of the central portion of the axle 102 is fixed to the axle supporting fixture 214.

As such, when the operation panel 290 is operated while the axle 102 is fixed, the control unit 242 of the data collecting unit 240 operates the transfer jig 230. That is, the control unit 242 rotates the first pinion 262 by driving the second motor 261, thereby moving the first rack member 264 in the front-rear direction, and detecting the defect in the axle press-fitting area 100. The sensor 220 is transferred. On the other hand, after the driving of the second motor 261 is completed, the third motor 271 is driven to rotate the second pinion 272 to transfer the second rack member 274 in the direction perpendicular to the axle 102. In this case, the defect detection sensor 220 is brought into contact with the axle press-fitting part 100.

As described above, when 2.0 A of alternating current I is introduced into the induction line 10 of the defect detection sensor 220 while the defect detection sensor 220 is in contact with the defect detection sensor 220, the induction current is applied to the surface of the axle injection portion 100. (I ') is derived. In this way, the potential difference ΔV is determined between the probe terminals 11 and 11 'arranged at 5 mm intervals from the surface of the axle indentation region 100 in which the induced current I' is induced, and the detected potential difference ( ΔV) is collected by the data collecting means 240 to detect the depth of the surface defect of the test axle 102 up to 2.0mm. At this time, when the axle 102 rotates within the range of 0 to 360 ° according to the operation of the first motor 210, a crack having a certain depth at a certain position through the rotation angle and the potential difference ΔV input through the encoder. Is detected, and the data value is displayed via the display means 250.

In the above, the defect flaw detection apparatus of the railway vehicle axle pressurization part was demonstrated. Such a technical configuration of the present invention will be understood by those skilled in the art that the present invention can be implemented in other specific forms without changing the technical spirit or essential features of the present invention.

And, the above-described embodiments are to be understood in all respects as illustrative and not restrictive, and the scope of the present invention is indicated by the appended claims rather than the foregoing description, and the meanings of the claims and All changes or modifications derived from the scope and equivalent concepts thereof should be construed as being included in the scope of the present invention.

As can be seen from the above description, according to the present invention, the defect of the axle pressing portion in the state where the axle and the wheel are coupled has an effect of accurately detecting the degree of defect by using the concentrated AC current.

In addition, while rotating the axle in the range of 0 ~ 360 ° has the effect of closely inspecting the surface defect degree of the axle indentation to the depth of the defect of 2.0mm.

Claims (9)

A shelf provided with a chuck and an axle supporting fixture to rotatably support the axle in a state in which the wheel is pressed; The housing is formed to be bent so that the contact surface is in close contact with the surface of the axle, the guide line for inducing an induced current to the surface of the axle by receiving an alternating current into the interior of the housing, and the potential difference on the surface of the axle guided the induced current A defect detection sensor composed of two probe terminals for measuring and detecting a potential difference by inducing a concentrated induction current into the axle indentation portion in which the wheel is pressed into the axle; Data collection means for determining whether there is a defect by using the potential difference [Delta] V detected by the defect detection sensor; And a display means for displaying the defect data collected by the data collecting means. The method of claim 1, The shelf flaw flaw detection apparatus of the rail vehicle axle indentation portion is further provided with a first motor that provides a constant rotational force so that the axle can rotate 0 ~ 360 ° about the central axis. delete The method of claim 1, The guide line has a length flaw detection apparatus for a rail vehicle axle indentation, characterized in that the length 40mm. The method of claim 1, The probe terminal is flaw detection device of the rail vehicle axle pressing portion, characterized in that the two intervals of 5mm. The method of claim 1, And a transfer jig for transferring the defect detection sensor to be in contact with the surface of the axle. The method of claim 6, The transfer jig; An axial feed means for controlling the defect detection sensor to move in the axial direction of the axle, and vertical transport means for contacting the defect detection sensor to the surface of the axle. Flaw detector at the site. The method of claim 7, wherein The axial conveying means is installed on one side of the body fixed to the shelf and the first pinion is meshed with the second motor and the first pinion provided on the motor shaft so that the first pinion in the longitudinal direction of the axle when the first pinion rotates. Defect flaw detection apparatus of the rail vehicle axle pressing portion, characterized in that the first rack member is moved forward and backward. The method of claim 7, wherein The vertical conveying means is installed at the end of the first rack member, the second pinion is meshed with the second pinion and the second pinion provided on the motor shaft, so that the second pinion is moved vertically in the center direction of the axle when the second pinion rotates. And an end of the second flaw detection member to which the defect detection sensor is fixed at an end thereof.

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