JP2012237662A - Method for inspecting rail bottom face at concealed part of railway rail and inspection head used therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for inspecting a rail bottom face at a concealed part of a railway rail, which has higher resolution of a flaw than ever before and can detect a position of the flaw in a longitudinal direction of the rail and in a cross direction with respect to the longitudinal direction, and an inspection head used for the method.SOLUTION: An ultrasonic probe for a surface wave 13 is brought into contact with a rail bottom face 2a at an exposed part of a rail 2. The surface wave is made enter the rail bottom face 2a and is transmitted toward a concealed part 3, and the reflected surface wave is received by the probe 13. The probe 13 is oscillated or is moved in a crossing direction with respect to a longitudinal direction of the rail during the contacting state of the probe 13, so that a flaw at the concealed part 3 is inspected.

Description

  The present invention relates to a method for inspecting a rail bottom surface in a concealing part of a rail for inspecting a flaw in a rail concealing part such as a railroad crossing part, and an inspection head used therefor.

  As a method for examining a flaw at the bottom of the rail, a method for transmitting / receiving ultrasonic waves downward from the top of the rail, or a method for generating a plate wave (guide wave) by exciting the entire bottom of the rail as shown in Patent Document 1. It has been known.

  In the former method, there is a problem that the inspection can be performed only directly below the top portion, and in particular, the inspection of the lower portion of the rail in the rail concealing portion such as a railroad crossing cannot be performed. Therefore, an attempt has been made to enable inspection of the rail bottom portion of the rail concealing portion by vibrating the entire rail bottom portion as a plate wave by the latter method.

  However, in the latter method, the flaw detection performance is still insufficient, and even if the position of the flaw relative to the longitudinal direction of the rail can be roughly determined, the entire rail bottom is vibrated. It was impossible to detect the position of the flaw in the orthogonal direction.

JP 2008-107165 A

  In view of such a conventional situation, the present invention has a higher resolution of flaws than the conventional one, and the rail bottom surface in the concealing portion of the rail for rails capable of detecting the position of the flaw in the rail longitudinal direction and the crossing direction with respect to the rail longitudinal direction. It is an object of the present invention to provide an inspection method and an inspection head used therefor.

  In order to achieve the above object, the rail bottom surface inspection method in the concealing part of the railroad rail according to the present invention is characterized in that a surface wave ultrasonic probe is used, and the probe is disposed on the rail bottom surface at the exposed portion of the rail. , The surface wave is incident on the bottom of the rail and transmitted toward the concealing unit, and the reflected surface wave is received by the probe, and the probe is in contact with the probe. It is to inspect flaws of the concealing part by swinging or moving in the crossing direction with respect to the rail longitudinal direction.

  According to this method, the probe is brought into contact with the bottom surface of the exposed rail formed by digging the ground under the rail, etc., and the surface wave is incident on the bottom surface of the rail to receive the reflected wave. Is easy to implement. Further, the distribution of reflected signals in the cross direction with respect to the rail longitudinal direction can be detected by swinging or moving the probe in the cross direction with respect to the rail longitudinal direction while the probe is in contact. Therefore, coupled with the signal distribution in the rail longitudinal direction on the time axis, it is possible to detect the position of a flaw (in a two-dimensional plane) in the rail longitudinal direction and the direction intersecting with the rail longitudinal direction. Moreover, according to the experiments by the inventors, it was confirmed that the detection accuracy is improved because the present invention uses the surface wave compared to the case where the guide wave or the surface SH wave is used. . In addition, since the position of the flaw in the previous two-dimensional plane can be specified, it is understood that the resolution of the flaw is further improved as compared with the prior art.

  The said structure WHEREIN: The inspection head provided with the said probe may be provided, and this inspection head may be equipped with the gauge which can confirm the transmission direction of the said surface wave with respect to the said rail longitudinal direction. Further, the inspection head may include a gauge capable of confirming a moving distance in a crossing direction with respect to the rail longitudinal direction. In carrying out the inspection, it is preferable to dig a ground under the rail in a portion different from the concealing portion of the rail and bring the probe into contact with the bottom surface of the rail. The present invention is preferably implemented when the rail concealing portion is a crossing.

  On the other hand, the features of the inspection head used in the rail bottom surface inspection method in the railroad concealing portion described in any of the above features include a surface wave ultrasonic probe and a grip that supports these and can be gripped by hand. The probe is set so that a surface wave can be incident along the rail bottom surface and a reflected wave can be received by contacting the bottom surface of the rail, and the transmission direction of the surface wave with respect to the longitudinal direction of the rail and / or the rail It is further provided with a gauge capable of confirming the moving distance in the crossing direction with respect to the longitudinal direction.

  Here, the gauge may be a rod-shaped body. In this case, a pair of the rod-shaped bodies may be provided symmetrically in a direction intersecting the surface wave incident direction by the probe. The gauge may be an encoder that measures relative movement with respect to the rail.

  According to the above feature of the present invention, the inspection of the bottom surface of the rail in the concealing portion of the rail for rails that has a higher resolution of flaws than the conventional one and can detect the position of the flaw in the rail longitudinal direction and the crossing direction with respect to the rail longitudinal direction. It came to provide the method and the test | inspection head used for this.

  Other objects, configurations, and effects of the present invention will become apparent from the following embodiments of the present invention.

1 is a perspective view of a probe according to the present invention and a railroad railroad crossing in which inspection is performed using the probe. FIG. It is a longitudinal cross-sectional view of the hole vicinity in FIG. It is the sectional view on the AA line of FIG. It is a bottom view of FIG. It is a top view of a railroad crossing vicinity. This is a test rail with an artificial flaw. (A) is the direction of incidence of ultrasonic waves on the bottom surface of the test rail, and (b) is a transducer with a center frequency of 1 MHz. The graph which shows the test result in the case of using is shown, respectively. A comparative example is shown, (a) is a graph showing the incident direction of the ultrasonic wave at the bottom surface of the test rail, and (b) a graph showing a test result when a vibrator having a center frequency of 1 MHz is used. (A) shows the incident direction of the ultrasonic wave on the bottom surface of the test rail, and (b) shows the test result when the vibrator having a center frequency of 1 MHz is used. The graph to show is shown, respectively. The test result of FIG. 9 is shown, (a) is a graph which shows the measured value regarding the flaw I, (b) flaw II. 9A and 9B, the test is performed by swinging the probe at an end different from that in FIG. 9. FIG. 9A shows the incident direction of ultrasonic waves on the bottom surface of the test rail, and FIG. The graph which shows the test result in the case of using is shown, respectively. 11 shows the test results of FIG. 11, (a) is a graph showing a measurement value relating to flaw I, and (b) is a graph showing a measurement value relating to flaw II. It is a block diagram of the inspection device concerning the present invention. FIG. 3 is a view corresponding to FIG. 2 in the second embodiment of the present invention. FIG. 4 is a view corresponding to FIG. 3 in the second embodiment of the present invention. FIG. 5 is a view corresponding to FIG. 4 in the second embodiment of the present invention.

Next, the present invention will be described in more detail with reference to the accompanying drawings as appropriate.
FIG. 1 is a perspective view of an inspection head 10 according to the present invention and a railroad crossing (hidden part) 3 of a railroad track 1 to be inspected using the inspection head 10, and FIG. 5 is a plan view of the vicinity of the railroad crossing 3 of the railroad track 1. . As shown in FIG. 3, the rail 2 to be inspected has a rail top portion 2 d on a wide rail bottom portion 2 b via a rail intermediate portion 2 c and a rail top portion 2 d on the enlarged portion. The rail bottom surface 2a serving as an inspection object portion is formed flat.

  The two rails 2 in FIG. 2 are laid on the ground in parallel with a plurality of sleepers 6 spaced apart. The railroad crossing 3 is concealed by a road portion 5 made of mortar or the like so that the upper surface thereof is as high as the rail top 2d. Only a slight gap through which the wheel flange passes is provided between the rail 2 and the road portion 5, and it is difficult to inspect the inside of the rail 2, particularly the rail bottom 2 b where corrosion is a problem, from the rail top 2 d. The object of the present invention is to inspect the rail bottom 2b from the outside of the road portion 5. Specifically, the ground below the rail 2 near the road portion 5 is dug, and a hole H (first to fourth holes H1 to 4) is dug as shown in the figure. 10 is contacted, ultrasonic waves are transmitted to and received from the concealing portion 3 of the rail 2, and inspection is performed.

  As shown in FIGS. 1 to 4, the inspection head 10 includes an ultrasonic transducer 11 including an ultrasonic transducer 11 that generates a longitudinal wave and a wedge 12 that causes the longitudinal wave from the transducer 11 to enter the rail bottom surface 2a as a surface wave. A touch element 13 and a grip 14 that supports the wedge 12 and can be gripped by the hand G when the upper surface of the wedge 12 is brought into contact with the rail bottom surface 2a are provided. The wedge 12 is made of, for example, a material such as acrylic resin. For example, a vibrator 11 used for vertical flaw detection is attached obliquely to the upper surface of the wedge 12 so that surface waves can be incident on the rail bottom surface 2a. . The grip 14 is formed in a cylindrical shape so that it can be easily grasped, and can be made of a relatively elastic material if the strength of the mounting portion of the gauge 15 described later is compensated with another material.

  FIG. 13 is a block diagram of an inspection apparatus 100 according to the present invention. The inspection apparatus 100 includes an inspection head 10 including a vibrator 11 and a processing apparatus 101 connected to the vibrator 11 by a processing apparatus 101 and a code 17. And a display 106 for displaying the inspection result. The processing apparatus 101 includes an oscillator 102 that generates a transmission wave in the vibrator 11, a receiver 103 that transmits the rail 2 and receives a reception wave received by the vibrator 11 again, and a filter 104 that performs filtering of the reception wave. And a processing unit 105 for processing and displaying the received wave.

  As shown in FIGS. 1 to 4, in the inspection head 10, the incident direction W of the transmission wave is specified by the wedge 12. Moreover, since the test | inspection head 10 is made to contact the rail bottom face 2a, the incident direction W cannot be visually observed. Therefore, a pair of left and right gauges 15 are provided in the gauge direction V that is 90 degrees out of phase with respect to the incident direction W in the plane of the upper surface of the wedge 12. This gauge 15 is a rod-like body 16 having a distance measuring scale on its surface along the longitudinal direction, and a threaded portion 16 a provided at the base of the rod-like body 16 is screwed into a screw hole formed in the grip 14. It is made to fix to the grip 14 with the thread part 16a.

  4 is a state in which the incident direction W (first incident direction W1) coincides with the rail longitudinal direction D1, and the gauge direction V (first gauge direction V1) is present in the rail longitudinal intersecting direction D2. Match. When the inspection head 10 is swung and oriented in the second incident direction W2 while the wedge 12 is in contact with the rail bottom surface 2a, the gauge is oriented in the second gauge direction V2. Therefore, the inclination of the incident direction W (second incident direction W2) with respect to the rail longitudinal direction D1 is the inclination θ1 (90 degrees) between the rail longitudinal direction D2 and the rail longitudinal direction D1, and the second gauge direction V2 and the rail longitudinal direction D1. It is obtained by “θ1−θ2” which is a difference from the inclination θ2. Based on this “θ1−θ2” and the position of the inspection head 10 with respect to the rail longitudinal crossing direction D2, the relative positional relationship with the incident direction W can be roughly grasped, and coupled with the inspection results described later, The position can be estimated.

  Here, the measurement result implemented using the rail 2 as a test body which provided the flaw artificially is enumerated. As shown in FIG. 6, the test rail 2 has an overall length of 2500 mm, and artificial scratches are provided on the bottom surface of the rail every 500 mm from the right end. These scratches are I, II, They shall be called III and IV. The flaw I is a cube with a side of 10 mm and is formed at the upper end of the bottom. Scratch II is a cube having a side of 5 mm and is formed at the upper end of the bottom. Scratches III are cubes each having a side of 5 mm, and a pair is formed at a position 30 mm from the upper and lower ends of the bottom. Scratches IV are cubes each having a side of 10 mm, and a pair is formed at a position 30 mm from the upper and lower ends of the bottom.

  7 and 8 show the results of tests conducted by moving the probe to the cross (orthogonal) with respect to the rail longitudinal direction. 7 and 8 (a) show the incident direction of ultrasonic waves on the bottom surface of the test rail, and ultrasonic transmission from the right to the left is P1 from top to bottom with respect to the rail longitudinal cross direction D2. The test was performed at the position of ~ P3. Moreover, the ultrasonic transmission from the left to the right was tested at positions P4 to P6 from the top to the bottom in the rail longitudinal cross direction D2. An oscillator having a center frequency of 1 MHz was used, a high-pass filter 0.5 MHz was applied to the received signal, a low-pass filter was not applied, a sampling frequency of 50 MHz was used, and averaging was performed 64 times. These results are shown in FIG. In addition, the lower notation of the following each figure (b) is interpreted by the same meaning as the said description in FIG.

  According to the result of FIG. 7B, each measurement position cannot be made and the positions of I to IV in the rail longitudinal direction D1 can be read from the time axis, and the position of the flaw in the rail longitudinal direction D1 is specified. Further, although the measurement positions P1 cannot be performed and the intensities of I and II are remarkable, the positions of the flaws with respect to the rail longitudinal crossing direction D2 are also specified because the intensity decreases at the measurement positions P2 and P3. According to the experiments by the inventors, it was possible to specify the position of the rail flaw in the range of the center frequency of about 0.2 MHz to 2 MHz.

  FIG. 8 shows a comparative example in which a surface SH wave probe is used instead of the inspection head 10. In this example, scratch II does not appear in any case, which is insufficient in terms of the inspection of the scratch, and the superiority of using the longitudinal surface wave of the present application can be seen.

  9 to 12 relate to the case where the test is performed by swinging the inspection head 10, and the same inspection head 10 as that in FIG. 7 is used. In each of FIGS. 9A and 9B, an ultrasonic wave is transmitted from the right end center of the rail 2 toward the left side and a reflected wave is received, and the measurement position Q1 is measured toward the flaw I and the measurement position Q2 is measured toward the flaw II. The position Q3 corresponds to the case where ultrasonic waves are transmitted and received toward the symmetrical position of the scratch I, and the measurement position Q4 corresponds to the symmetrical position of the scratch II.

  According to the result of FIG. 9B, the positions of the measurement positions I to IV in the rail longitudinal direction D1 cannot be read from the time axis, and the position of the flaw in the rail longitudinal direction D1 is specified. Further, according to the comparison between FIGS. 10A and 10B, since the values of flaws I and II are low at the measurement positions Q3 and 4, the position of the flaw with respect to the rail longitudinal cross direction D2 is also specified. Further, in these comparisons, since the maximum value differs at the measurement positions Q1 and Q2, taking into account the arrangement of flaws in the rail longitudinal direction D1, the rail longitudinal crossing direction D2 direction of flaws I and II depending on the previous incident direction W Can be estimated.

  11A, an ultrasonic wave is transmitted from the center of the left end to the right side of the rail 2 and a reflected wave is received, the measurement position Q5 is directed to one flaw IV, and the measurement position Q6 is the other one. Toward the scratch III, the measurement position Q7 corresponds to the case of transmitting and receiving ultrasonic waves toward the other scratch IV, and the measurement position Q8 toward the other scratch III, respectively.

  According to the result of FIG. 11B, each measurement position cannot be made and the positions of I to IV in the rail longitudinal direction D1 can be read from the time axis, and the position of the flaw in the rail longitudinal direction D1 is specified. 12 (a) and 12 (b), flaw III has a high value at measurement position Q6, taking into account the arrangement of flaws in the rail longitudinal direction D1, and flaws I and II depending on the previous incident direction W. It is possible to estimate the position in the rail longitudinal crossing direction D2.

Next, a second embodiment of the present invention will be described with reference to FIGS. The same code | symbol is attached | subjected to the member similar to 1st embodiment.
In the present embodiment, the above-described gauge is constituted by first and second encoders 34 and 36. That is, the inclination of the incident direction W with respect to the rail longitudinal direction D1 and the variation of the probe 13 with respect to the rail longitudinal direction D2 are both controlled by the first and second motors 33 and 35, and the first and second encoders 34, 36.

  The inspection head 30 includes a moving block 31 and a probe 13, and the probe 13 is supported on the lower side of an overhanging portion 31 b that projects from the block base portion 31 a of the moving block 31 through 33 a of 33 a. Yes. The inspection head 30 has the upper surface of the block base portion 31a and the upper surface of the wedge 12 in contact with the rail bottom surface 2a, and a support belt 40 made of an elastic material such as rubber or resin is wound around the rail 2 and the moving block 31 and tightened. By fixing with the fixing tool 41, the probe 13 and the moving block 31 are suspended and supported by the lower part of the rail bottom part 2b. Two rollers 32 are interposed between the moving block 31 and the support belt 40, and the probe 13 and the moving block 31 in the rail longitudinal crossing direction D2 in a state where the wedge 12 is in contact with the rail bottom surface 2a. Allow movement.

  The movement measuring belt 45 made of an elastic material such as rubber or resin is wound around the rail 2, and the movement measuring belt 45 is fixed to the rail bottom surface 2 a by tightening and fixing with a measuring belt fixture 46. Rack-like teeth are provided on the outer surface of the movement measuring belt 45, and mesh with a toothed pulley 36 attached via a shaft 35a of the second motor 35. The first and second motors 33 and 35 are both geared motors, and the probe 13 is rotated relative to the overhanging portion 31b by a desired angle or distance by detecting the positions of the first and second encoders 34 and 36. Or relative movement.

  Finally, reference is made to the possibilities of yet another embodiment of the invention. In the first embodiment, the inspection head is held by 10 hands. For example, as shown by reference numeral 20 in FIG. 3, the traction tool made of an elastic material as described above is attached to the rail 2 and the inspection head 10 (a pair of rod-shaped bodies 16,. 16), the inclination in the incident direction may be adjusted by operating the rod-shaped body 16 by hand.

  The probe in the present invention only needs to be able to transmit and receive surface waves from the transducer 11, and is not limited to one using a wedge as in the above-described embodiment.

  INDUSTRIAL APPLICABILITY The present invention can be used as a method for inspecting a rail bottom surface in a concealing portion of a railroad rail, such as a railroad crossing, and a probe used for this.

1: railroad track, 2: rail, 2a: rail bottom, 2b: rail bottom, 2c: rail middle, 2d: rail top, 3: railroad crossing (hiding part), 5: road, 6: sleepers, 10: Inspection head, 11: vibrator, 12: wedge, 13: probe, 14: grip, 15: gauge, 16: rod-like body, 16a: screw part, 16b: lock nut, 17: cord, 20: traction tool, 30: Inspection head, 31: Moving block, 31a: Block base, 31b: Overhang, 32: Roller, 33: First motor, 33a: Shaft, 34: First encoder, 35: Second motor, 35a: Shaft 36: second encoder, 40: support belt, 41: support belt fixture, 45: moving measurement belt, 46: measurement belt fixture, 100: inspection device, 101: processing device, 102: oscillator, 10 : Receiver, 104: Filter, 105: Processing unit, 106: Display, D1: Rail longitudinal direction, D2: Rail longitudinal cross direction, G: Hand, H: Hole, H1-4: First to fourth holes, V : Gauge direction, V1,2: First, second gauge direction, W: Incident direction, W1,2: First, second incident direction

Claims (9)

Using a surface wave ultrasonic probe, the probe is brought into contact with the bottom surface of the rail at the exposed portion of the rail, the surface wave is incident on the bottom surface of the rail, transmitted toward the concealing portion, and the reflected surface wave is transmitted. The rail of the rail for inspecting a flaw of the concealing portion by receiving the probe and moving the probe in a crossing direction with respect to the longitudinal direction of the rail while the probe is in contact with the probe. Inspection method of rail bottom surface in concealment part. The rail bottom surface inspection method according to claim 1, wherein an inspection head including the probe is provided, and the inspection head includes a gauge capable of confirming a transmission direction of the surface wave with respect to the rail longitudinal direction. The rail bottom surface inspection method according to claim 1, wherein the inspection head includes a gauge capable of confirming a moving distance in a crossing direction with respect to the rail longitudinal direction. The rail bottom surface inspection method according to any one of claims 1 to 3, wherein the rail bottom surface in a portion different from the rail concealing portion is dug, and the probe is brought into contact with the rail bottom surface. The rail bottom surface inspection method according to claim 1, wherein the rail concealing portion is a crossing. It is an inspection head used for the inspection method of the rail bottom in the concealing part of the rail for rails according to any one of claims 1 to 5,
Provide a surface wave ultrasonic probe and a grip that supports these and can be gripped by hand,
The probe is set so that a surface wave can be incident along the rail bottom surface and a reflected wave can be received by making contact with the rail bottom surface,
An inspection head further comprising a gauge capable of confirming a moving distance of the surface wave in the longitudinal direction with respect to the rail longitudinal direction and / or a moving distance in the cross direction with respect to the rail longitudinal direction. The inspection head according to claim 6, wherein the gauge is a rod-shaped body. The inspection head according to claim 7, wherein a pair of the rod-like bodies are provided symmetrically in a direction intersecting with a surface wave incident direction by the probe. The inspection head according to claim 6, wherein the gauge is an encoder that measures relative movement with respect to the rail.

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