JP2001305111A - Ultrasonic rail flaw detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ultrasonic rail flaw detector which can detect both of bottom corrosion and web transverse fissures by achieving a highly sensitive detection of the bottom corrosion. SOLUTION: A transmitting/receiving vibrator 12 is arranged to contact the top surface of a rail 1. A longitudinal ultrasonic wave within the range of 10 deg.-25 deg. in angle of refraction is admitted into the rail from the transmitting/ receiving vibrator 12. A part of the ultrasonic wave scattered by corrosion 1B at the bottom of the rail is received by the transmitting/receiving vibrator 12 and the ultrasonic wave radiated from the transmitting/receiving vibrator 12 and reflected on a defect 1C and the bottom surface of the rail is received by a receiving vibrator 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic rail flaw detector capable of detecting bottom corrosion of a rail or lateral abdominal tear using an ultrasonic wave.

[0002]

2. Description of the Related Art Conventionally, a device for detecting a defect such as a flaw existing inside a rail such as a railroad rail using ultrasonic waves has been known.
Widely used on railway track maintenance sites. Ultrasonic waves are made to enter the rail from the tread surface, which is the top surface of the rail, and the presence of a flaw can be known by detecting a reflected echo from an internal flaw or the like. In the conventional ultrasonic inspection of a rail, as shown in FIG. 6, ultrasonic waves are incident on the rail 1 at various angles using a plurality of ultrasonic
Flaw detection is performed by receiving reflected echoes from flaws generated in each part. Typically, the vertical probe 40 has a longitudinal wave ultrasonic wave whose refraction angle of the ultrasonic wave is 0 °, the transverse wave ultrasonic wave 35 ° to 45 ° formed by the oblique probes 42, 42, and the oblique probe 44. , 44 are used.

[0003] As shown in FIG. 7, regarding a lateral crack 1A generated at the bottom of the rail, the ultrasonic wave incident from the probe into the rail repeats reflection at the corner, and consequently returns in the incident direction. Bevel probe 4
2 can be detected with high sensitivity using the transverse ultrasonic waves of 35 ° to 45 °.

[0004]

However, it is not always possible to sufficiently detect the bottom corrosion occurring at the bottom of the rail with a conventional probe. This is because, as shown in FIG. 8, in the case of corrosion 1B on the bottom of the rail, the angle of the surface due to the corrosion 1B is lying, so that it is reflected in a direction different from that of the probe. One reason is that a sufficient reception signal level cannot be obtained because the reception signal is weakened due to scattering and reflection due to the irregular surface.

[0005] In addition, the bottom probe 1B is drawn by a method of drawing a B scope using a vertical ultrasonic wave of 0 ° by the vertical probe 40.
However, since the level of the bottom echo is large and the level of the scattered reflection from the bottom corrosion 1B is low, the reception amplification is increased to draw an image.
m difference in rail height must be read,
There is a problem that the device becomes complicated.

[0006] Further, as for the defect 1C (see FIG. 9) such as a lateral crack with insufficient penetration generated in the abdomen of the rail welding portion, since the surface is smooth, almost all components of the incident ultrasonic waves are reduced to the bottom of the rail. There is a problem that almost no detection can be performed because there is a small amount of a component that is specularly reflected in the direction and returns in the direction of the probe. Therefore, as shown in FIG. 9, a tandem flaw detection method of manually scanning a probe using two probes (a transmission probe 46 and a reception probe 48) has been proposed and implemented. . However, in this method, in order to detect the entire area from the head to the bottom of the rail, the relative position of each probe in the front-rear direction of the rail must be moved and scanning is performed. In such applications, there is a problem that the moving speed is limited.

There is also a method of using a probe having a wide aperture surface as a method of detecting a flaw in the entire area without scanning the probe. However, there is a problem that the size of the probe is increased and the cost is increased. is there.

SUMMARY OF THE INVENTION The present invention has been made in view of the problems of the conventional rail flaw detection, and a first object is to provide an ultrasonic rail flaw detection apparatus capable of detecting bottom corrosion with high sensitivity. .

A second object of the present invention is to reduce the trouble of adjusting the relative position in the front-rear direction between the transmitting transducer and the receiving transducer in the ultrasonic testing apparatus using the tandem testing method. An ultrasonic rail flaw detector is provided.

It is a third object of the present invention to provide an ultrasonic rail flaw detector capable of detecting both bottom corrosion and abdominal lateral crack.

[0011]

In order to achieve the above object, an invention according to claim 1 is an ultrasonic rail flaw detector which detects flaws on a rail by using ultrasonic waves and detects corrosion of the bottom of the rail. A transmitting / receiving vibrator is provided in contact with the top surface of the rail. A longitudinal ultrasonic wave having a refraction angle in the range of 10 ° to 25 ° is incident on the rail from the transmitting / receiving vibrator, and is scattered by corrosion of the rail bottom. A part of the ultrasonic waves thus received is received by the transmitting / receiving vibrator. By setting the angle of refraction of longitudinal ultrasonic waves from the transmitting and receiving transducer to be in the range of 10 ° to 25 °,
Without being affected by the bottom echo, the ultrasonic wave scattered by the corrosion of the rail bottom can be received with relatively good sensitivity,
We can know the existence of corrosion.

According to a second aspect of the present invention, there is provided an ultrasonic rail flaw detector for detecting a flaw of a rail using ultrasonic waves, wherein the transmitting vibrator and the receiving vibrator are arranged in the front-rear direction of the rail and abut on the rail. And the transmitting transducer has a refraction angle of 10 °.
Inject longitudinal ultrasonic waves in the range of ~ 25 ° into the rail,
The receiving transducer receives the ultrasonic waves radiated from the transmitting transducer and reflected by the defect and the rail bottom surface. The angle of refraction of longitudinal ultrasonic waves from the transmitting transducer is 1
By setting the angle in the range of 0 ° to 25 ° to be smaller than the angle of refraction in the case of using the transverse ultrasonic wave in the conventional tandem flaw detection method, the size of the transmitting oscillator can be increased without increasing the size of the transmitting oscillator. The range of the height of the radiated ultrasonic wave in the rail can be widened, and therefore, the trouble of adjusting the relative position between the transmitting transducer and the receiving transducer in the front-rear direction can be reduced, and the defect in the rail can be reduced. Can be detected.

In particular, when the height of the rail is h and the angle of refraction of the longitudinal ultrasonic wave from the transmitting oscillator is θ, the rail of the transmitting oscillator is preferably provided. By setting the magnitude in the direction perpendicular to the width direction of h to sinh θ, the longitudinal wave transmitted from the transmitting transducer without moving the relative position of the transmitting transducer and the receiving transducer in the front-rear direction. It is possible to detect a defect somewhere along the entire height of the rail by ultrasonic waves.

According to a fourth aspect of the present invention, there is provided an ultrasonic rail flaw detector for detecting flaws in a rail by using ultrasonic waves, wherein the transmitting / receiving vibrator and the receiving vibrator are arranged in the longitudinal direction of the rail and abut on the rail. And the transmitting / receiving vibrator has a refraction angle of 1
A longitudinal ultrasonic wave in a range of 0 ° to 25 ° is made incident on the rail, and the longitudinal ultrasonic wave from the rail is received. Receiving the ultrasonic wave reflected from the optical disc. Longitudinal ultrasonic waves having a refraction angle of 10 ° to 25 ° are radiated from the transmitting / receiving vibrator, and the longitudinal ultrasonic waves scattered and returned by the corrosion of the bottom of the rail are received by the transmitting / receiving vibrator, thereby causing corrosion of the rail bottom. Can be detected. Also,
When there is a defect in the rail, the longitudinal ultrasonic wave with a refraction angle of 10 ° to 25 ° emitted from the transmitting and receiving transducer is reflected by the defect in the rail and further reflected by the bottom of the rail for reception. A defect inside the rail can be detected by using a so-called tandem flaw detection method, which is received by a vibrator. In this way, by using one transmitting and receiving transducer in common,
Both corrosion at the bottom of the rail and defects such as lateral cracks inside the rail can be detected. By setting the refraction angle of the longitudinal ultrasonic wave radiated from the transmitting / receiving vibrator in the range of 10 ° to 25 ° and smaller than the refraction angle when using the conventional transverse ultrasonic wave, the transmitting / receiving vibrator is set. Without increasing the size, the range of the height direction of the rail of the ultrasonic wave radiated from the transmitting / receiving transducer can be expanded, and therefore, the relative position of the transmitting / receiving transducer and the receiving transducer in the front-back direction can be increased. The defect in the rail can be detected with less trouble of adjustment.

In particular, when the height of the rail is h and the angle of refraction of longitudinal ultrasonic waves from the transmitting / receiving transducer is θ, the rail of the transmitting / receiving transducer is provided. By setting the size in the direction perpendicular to the width direction of h to sinh θ, the longitudinal wave transmitted from the transmitting / receiving vibrator without moving the relative position of the transmitting / receiving vibrator and the receiving vibrator in the front-rear direction. It is possible to detect a defect somewhere along the entire height of the rail by ultrasonic waves.

Further, the invention according to claim 6 is characterized in that the transmitting / receiving vibrator and the receiving vibrator are connected to the same receiving unit via respective changeover switches. By switching through the changeover switch, it is possible to switch between detection of corrosion at the bottom of the rail and detection of a defect inside the rail using the same receiving unit.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a structural explanatory view showing an embodiment of an ultrasonic rail flaw detector of the present invention, and FIG. 2 is a perspective view showing a state when performing rail flaw detection.

This ultrasonic rail flaw detector transmits an ultrasonic pulse to the inside of the rail 1 and mainly removes the bottom corrosion 1B of the rail 1.
Transmitting / receiving vibrator 12 for receiving the reflected echo reflected from the antenna, and the ultrasonic pulse transmitted from the transmitting / receiving vibrator 12 is mainly reflected by the abdominal defect 1C, reflected at the bottom of the rail, and returned. Resonator 1 for receiving reflected echo
4 has an ultrasonic probe 10. The transmitting / receiving vibrator 12 and the receiving vibrator 14 are acoustically isolated by the division film 16. Further, the transmitting / receiving vibrator 12
A resin shoe 1 for allowing ultrasonic pulses generated by the vibrator 12 to enter the rail 1 at a specified incident angle
8 are provided, and a rail 1 is provided on the front surface of the receiving vibrator 14.
A shoe 19 for transmitting the ultrasonic wave incident from the to the receiving transducer 14 is provided. The ultrasonic probe 10 includes a transmitting unit 20 that generates an electric pulse for transmitting an ultrasonic pulse from the transmitting / receiving vibrator 12 and a receiving unit that receives and amplifies a signal received by the transmitting / receiving vibrator 12. Unit 22 and a receiving unit 2 that receives and amplifies a signal received by the receiving transducer 14
4 are connected. Further, detection display units 26 and 28 are connected to the reception unit 22 and the reception unit 24, respectively. The detection display units 26 and 28 are for displaying when a reception signal larger than a predetermined threshold is received by the reception units 22 and 24 to indicate that a reception echo has occurred. Illumination indicates that there is a received echo.

The ultrasonic pulse emitted from the transmitting / receiving vibrator 12 enters the rail 1 via the shoe 18 at a specified angle. The prescribed angle is such that longitudinal waves having a refraction angle θ in the range of 10 ° to 25 °, preferably 15 ° to 20 °, are generated in the rail 1 in accordance with Snell's law. To be selected.

As shown in FIG. 1, the size L of the transmitting / receiving vibrator 12 substantially in the front-rear direction, that is, the size L in the direction perpendicular to the width direction of the rail, is defined assuming that the height of the rail is h. ,

[0021]

L = h × sin θ (1) The interval P between the transmitting / receiving vibrator 12 and the receiving vibrator 14 is approximately

[0022]

## EQU2 ## It is set so as to satisfy P = h × tan θ (2). However, the interval P between the transmitting / receiving vibrator 12 and the receiving vibrator 14 is not limited to this, and the rail P emitted from the transmitting / receiving vibrator 12
The receiving transducer 14 is arranged in a range where the ultrasonic wave reflected by the abdominal defect and reflected by the bottom of the rail can be received.

In the ultrasonic rail flaw detector configured as described above, an ultrasonic pulse emitted from the transmitting / receiving vibrator 12 is incident on the rail 1 at a refraction angle θ. If there is no corrosion 1B or a defect 1C due to insufficient penetration at the bottom of the rail 1, the ultrasonic pulse is reflected at the bottom of the rail 1, reflected forward, and does not return to the transmitting / receiving vibrator 12.

On the other hand, when the bottom corrosion 1B is present on the rail 1, as shown in FIG. 3, the ultrasonic wave is scattered and reflected by the corroded portion 1B, and a part of the ultrasonic wave is transmitted to the transmitting / receiving vibrator 12. Come back. The reflected echo is converted into an electric signal by the transmitting / receiving vibrator 12, amplified by the receiving unit 22, and displayed on the detection display unit 26. From this display, it can be known that the bottom corrosion 1B exists on the rail 1. The angle of refraction θ is 10 ° to 25 °, preferably 15 ° to 20 °, which is a relatively small angle.
Scattered reflection easily returns to the transmitting / receiving vibrator 12. On the other hand, unlike the case of the vertical probe, the refraction angle θ is larger than 0 °, so that the influence of the bottom echo can be significantly reduced.

FIGS. 10 and 11 show experimental examples in which the relationship between the refraction angle θ and the bottom corrosion detection performance was obtained. In order to realize a plurality of refraction angles, an acrylic shoe 18 is manufactured,
The performance of detecting bottom corrosion was evaluated in combination with a transmitting / receiving transducer. The evaluation was performed by measuring the echo level from the bottom corrosion and the echo level from the bottom surface of the sound rail without bottom corrosion for a plurality of refraction angles, and comparing the SN ratio. The following table shows the components used in the experiment.

[0026]

[Table 1] First, as shown in FIG. 10 (a), the measurement was performed by standardizing the echo level of the φ5 side hole, and the echo level of the bottom of the sound rail shown in FIG. 10 (b) was measured.
(C) The echo level of the corroded rail was measured, and the SN ratio at each refraction angle was compared. The measurement results are shown in the following table and FIG.

[0027]

[Table 2] As can be seen from the above measurement results, the refraction angle is 10 ° to 25 °.
The S / N ratio is good at the above angle, and the sensitivity is particularly good at 15 °. The transmitting / receiving vibrator 1 is set to have such a range of the refraction angle.
It is effective to set a refraction angle of 2.

Next, as shown in FIG. 4, when there is a vertical plane transverse crack 1C such as insufficient penetration that is likely to occur at the welded portion of the rail 1 or the like, it is sent out from the transmitting / receiving vibrator 12. The reflected ultrasonic pulse is reflected by this lateral crack 1C,
Further, the light is reflected by the bottom surface of the rail 1 and received by the receiving transducer 14. This signal is amplified by the receiving unit 24 and is displayed on the detection display unit 28. From this display, it can be detected that a lateral crack exists in the abdomen of the rail 1. When the transmitting / receiving vibrator 12 satisfies the expression (1), the lateral crack 1C
Irrespective of the height of the rail 1, the ultrasonic wave radiated from the transmitting / receiving transducer 12 covers the entire height of the rail 1, and the ultrasonic pulse is always reflected by the lateral crack 1 </ b> C. You. When the receiving transducer 14 satisfies the expression (2), the reflected ultrasonic pulse is reflected on the bottom surface and is reliably received by the receiving transducer 14. When detecting the lateral crack 1C, the refraction angle θ does not necessarily need to be 10 ° to 25 °, and can be detected at any other angle. And the size of the ultrasonic probe 10 increases. However, by setting the refraction angle in the above-mentioned angle range, the ultrasonic probe 1
0 can be avoided.

FIG. 5 is a diagram showing a second embodiment of the present invention. In the figure, the same members as those of the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

In this embodiment, the receiving unit 24 and the detection display unit 28 of the first embodiment are omitted, and instead, the changeover switch 30 is connected to the receiving unit 22, the transmitting / receiving vibrator 12, and the receiving vibrator 14. The receiving unit 22 can be selectively connected to the transmitting / receiving vibrator 12 or the receiving vibrator 14.

By switching the changeover switch 30, it is possible to switch between bottom corrosion 1B detection and lateral crack 1C detection according to the purpose by using the same receiving unit 22 and detection display unit 26.

In each of the above-described embodiments, the detection of the bottom corrosion 1B and the detection of the lateral crack 1C are performed by one transmitting / receiving vibrator 12, so that the number of vibrators can be reduced and the space under the floor of a flaw detection vehicle or the like can be reduced. I will be able to help.

[0033]

As described above, according to the first aspect of the present invention, the refraction angle of the longitudinal ultrasonic wave from the transmitting / receiving vibrator is set in the range of 10 ° to 25 °, so that the bottom surface echo can be reduced. Without being affected, the ultrasonic waves scattered by the corrosion of the rail bottom can be received with relatively good sensitivity, and the presence of the corrosion can be detected.

According to the second aspect of the present invention, the range of the height direction of the rail of the ultrasonic wave radiated from the transmitting transducer can be increased without increasing the size of the transmitting transducer. Therefore, it is possible to detect a defect in the rail while reducing the trouble of adjusting the relative position between the transmitting / receiving vibrator and the receiving vibrator in the front-rear direction.

According to the third aspect of the present invention, the adjustment of the relative position between the transmitting oscillator and the receiving oscillator in the front-rear direction is reduced, and the rail is transmitted by the longitudinal ultrasonic waves transmitted from the transmitting oscillator. Can be detected somewhere in the entire height direction.

According to the fourth aspect of the present invention, it is possible to detect both corrosion at the bottom of the rail and a defect such as a lateral crack inside the rail by using one transmitting / receiving vibrator in common. By setting the refraction angle of longitudinal ultrasonic waves radiated from the transmitting / receiving transducer to a range of 10 ° to 25 °, by setting the refraction angle to be smaller than the refraction angle when using conventional transverse ultrasonic waves,
Without increasing the size of the transmitting / receiving vibrator, the range of the height direction of the rail of the ultrasonic wave radiated from the transmitting / receiving vibrator can be increased, and therefore, the front-rear direction between the transmitting / receiving vibrator and the receiving vibrator can be increased. Can be detected without moving the relative position of the rails.

According to the fifth aspect of the present invention, the height of the rail is increased by the longitudinal ultrasonic waves transmitted from the transmitting / receiving transducer without moving the relative position of the transmitting / receiving transducer and the receiving transducer in the front-rear direction. Defects somewhere along the entire height can be detected.

According to the sixth aspect of the present invention, it is possible to switch between detection of corrosion at the bottom of the rail and detection of a defect inside the rail using the same receiver.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating an embodiment of an ultrasonic rail flaw detector according to the present invention.

FIG. 2 is a perspective view of the ultrasonic rail flaw detector of FIG. 1;

FIG. 3 is an explanatory view showing the principle of detecting corrosion of a rail bottom of the ultrasonic rail flaw detector of FIG. 1;

FIG. 4 is an explanatory diagram showing the principle of detecting an abdominal lateral crack in the ultrasonic rail flaw detector of FIG. 1;

FIG. 5 is a block diagram illustrating a second embodiment of the ultrasonic rail flaw detector according to the present invention.

FIG. 6 is a configuration diagram illustrating a conventional ultrasonic rail flaw detector.

FIG. 7 is an explanatory view showing reflection of ultrasonic waves with respect to a lateral crack generated at the bottom of the rail.

FIG. 8 is an explanatory diagram showing reflection of ultrasonic waves with respect to corrosion of a rail bottom.

FIG. 9 is a configuration diagram of an ultrasonic rail flaw detector using a conventional tandem flaw detection method.

FIGS. 10A to 10C are explanatory diagrams illustrating an experimental example for obtaining a relationship between a refraction angle and a bottom corrosion detection performance.

FIG. 11 is a graph showing the experimental results of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rail 1B Corrosion of bottom 1C Abdominal lateral crack 12 Transceiver for transmission and reception 14 Transducer for reception 22 Receiver 30 Changeover switch

Claims (6)

[Claims] 1. An ultrasonic rail flaw detector for detecting flaws on a rail by detecting flaws on the rail using ultrasonic waves, comprising: a transmitting / receiving vibrator abutting on a top surface of the rail; A longitudinal wave having a refraction angle of 10 ° to 25 ° is incident on the rail from the vibrator, and a part of the ultrasonic wave scattered by the corroded portion on the bottom of the rail is received by the transmitting / receiving vibrator. Ultrasonic flaw detector. 2. An ultrasonic rail flaw detector for flaw-detecting a rail using ultrasonic waves, comprising: a transmitting vibrator and a receiving vibrator aligned in the rail front-rear direction and abutting on the rail. Credit transducer has a refraction angle of 1
A longitudinal wave ultrasonic wave in a range of 0 ° to 25 ° is incident on the rail, and the receiving vibrator receives the ultrasonic wave radiated from the transmitting vibrator and reflected on the defect and the bottom surface of the rail. Ultrasonic flaw detector. 3. When the height of the rail is h and the angle of refraction of longitudinal ultrasonic waves from the transmitting transducer is θ, the size of the transmitting transducer in a direction perpendicular to the width direction of the rail. Is h × s
3. The ultrasonic rail flaw detector according to claim 2, wherein in θ is set as inθ. 4. An ultrasonic rail flaw detector for detecting flaws on a rail by using ultrasonic waves, comprising: a transmitting / receiving vibrator aligned in the longitudinal direction of the rail and abutting on the rail; The vibrator makes longitudinal wave ultrasonic waves having a refraction angle of 10 ° to 25 ° incident on the rail and receives longitudinal wave ultrasonic waves from inside the rail,
An ultrasonic rail flaw detector, wherein the receiving transducer receives ultrasonic waves radiated from the transmitting / receiving transducer and reflecting the defect and the rail bottom surface. 5. When the height of the rail is h and the angle of refraction of longitudinal ultrasonic waves from the transmitting and receiving transducer is θ, the size of the transmitting and receiving transducer in a direction perpendicular to the width direction of the rail. H
The ultrasonic rail flaw detector according to claim 4, wherein x is sin θ. 6. The ultrasonic rail flaw detector according to claim 4, wherein the transmitting / receiving vibrator and the receiving vibrator are respectively connected to the same receiving unit via a changeover switch.