JP2000146922A - Method and device for ultrasonic crack detection of wheel set - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce checking costs by the non-overhaul of a wheel set, and to improve the reliability of checking by press-fit echo reduction by operating the crack detection of all interfit parts from the face of a wheel set at the time of the ultrasonic crack detection test of a wheel set for a vehicle or the like. SOLUTION: This is an angle beam method for detecting material cracks in the neighborhood of an axial outer peripheral face including interfit parts 108 and 109 of a wheel set 101 for a train into which a wheel set 102 or a gear 51 are interfit by an ultrasonic probe 21 set on an axial edge face 105. The probe 21 is constituted so that slide type vibrators for generating SH ultrasonic waves can be arranged like an array, and the propagating direction (angle of refraction θ) and converged position of ultrasonic beams can be controlled by the electronic scanning of an ultrasonic crack detector 20. In this case, the angle of refraction θ = 90 deg.C - an incident angle αwhich is an incident angle to the normal of the face of a part to be inspected. The incident angle α is selected so that the part to be inspected can escape a dead angle due to a level cutting part 107. Then, the number of skips or road length W for converting the beams on the part to be inspected are decided based on the angle of refraction θ.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic flaw detection test, and more particularly to an ultrasonic flaw detection test method suitable for inspecting a flaw in a wheel axle for a railway vehicle or the like.

[0002]

2. Description of the Related Art The outer peripheral surface of a wheel set of a railway vehicle or the like is liable to cause material damage at a contact portion with a fitting member or a sliding member. As shown in FIG. 11, a conventional axle flaw detection device includes an axle 101 and a wheel 1.
02 and ultrasonic flaw detection of the fitting portions 110 to 113 of the gear 103,
As shown in (a), the operation is performed from both the end surface 105 of the shaft and the bearing surface 104 shown in (b).

[0003] Of the fitting parts to be inspected, a wheel fitting outer edge part
Since the ultrasonic beam 210 does not reach 110 because of being blocked by the step cutting portion 107 of the shaft, flaw detection from the shaft end face 105 cannot be performed.
For this reason, ultrasonic waves are incident from the bearing surface 104 and the step
The ultrasonic beam is allowed to reach the wheel fitting outer edge portion 110 without being interrupted by 07 (for example, see Japanese Unexamined Patent Application Publication No.
No. 43).

The flaw detection from the shaft end face 105 can be performed by removing the shaft end cover 63. However, flaw detection from the bearing surface 104 cannot be performed unless the vehicle (not shown) is disassembled, the bogie frame 60 is removed, and the bearing 61 is disassembled, as shown in FIG. Spending. In addition, since the angle of refraction of the ultrasonic wave used (the angle of the ultrasonic beam with respect to the normal to the surface of the material to which the probe is applied) differs depending on the part to be inspected, prepare a plurality of probes according to the inspection part. The probe had to be replaced every time the area to be flawed changed.

[0005] There are two types of vibration of ultrasonic waves used for flaw detection tests: longitudinal waves and transverse waves. As shown in FIG. 13A, the longitudinal waves vibrate so that the particles of the material are displaced in parallel with the propagation direction of the ultrasonic wave. On the other hand, the transverse wave vibrates perpendicular to the propagation direction, and as shown in FIG.
SV ultrasonic waves displaced in a direction nearly perpendicular to
As shown in (c), there is an SH ultrasonic wave displaced in parallel to the incident surface 114.

As shown in FIG. 14, the SV ultrasonic wave used in the conventional oblique flaw detection cannot obtain a sufficient reciprocating passage rate, that is, a practical ultrasonic intensity, when the refraction angle is 33 degrees or less. Also, in the case of SV ultrasonic waves, an ultrasonic echo called a press-fit echo is generated from a portion where two members are in contact with each other with a large surface pressure, such as a fitting portion, making it difficult to distinguish the echo from an echo due to a shaft defect. .

Below the refraction angle at which SV ultrasonic waves cannot be used, simultaneously generated longitudinal ultrasonic waves having a high reciprocating rate have been used. However, since the vibration mode of longitudinal wave ultrasonic waves is converted by two reflections at corners such as a flaw opened on the surface of a material, the attenuation of ultrasonic waves is large. As shown in FIG. 15, when the incident angle of the longitudinal wave is not near 0 ° or 90 °, which is perpendicular to the flaw, the reflected wave intensity R is remarkably reduced. Was.

[0008]

As described above, the conventional ultrasonic flaw detection from the shaft end face has a dead zone which is not reached because the ultrasonic wave is reflected by the stepped portion when the wheel shaft has a stepped portion or the like. . For this reason, it had to be used together with the flaw detection from the bearing surface.

In the case of oblique flaw detection for avoiding a dead zone, in the case of longitudinal waves, the detection performance significantly changes depending on the nature of the flaw.
Attenuation on the circumferential surface due to skip flaw detection is also remarkable. In the case of an SV wave converted from a longitudinal wave, there are various problems, such as limitations on the angle of refraction of the ultrasonic wave, and difficulty in identifying a flaw by a press-in echo even with a usable angle of refraction. Was.
One of the problems with these longitudinal waves and SV waves is that the loss due to mode conversion is large.

The present inventors have paid attention to the fact that SH waves are less likely to cause mode conversion and have less loss associated with the conversion, and have studied the use thereof. And Japanese Patent Application No. 9-174269
Japanese Patent Application No. Hei 10-143346, in which an ultrasonic sensor is used to detect an ultrasonic flaw from the shaft end of a wheel press-fitting part using an SH wave. The invention realized by the electronic scanning method has been proposed.

An object of the present invention is to further develop the use of SH waves in the above-mentioned prior application, and to develop a practically usable S wave in wheel axle inspection.
It is an object of the present invention to clarify the effective range of the refraction angle of the H beam and to realize a method of automatically determining the path of an ultrasonic wave when the skip method is applied. As a result, an ultrasonic flaw detection method and apparatus capable of efficiently and highly accurately inspecting material flaws generated on a fitting surface of a wheel set for a railway vehicle or the like from a shaft end face are provided.

[0012]

DISCLOSURE OF THE INVENTION The present invention has been made by paying attention to a test result in which an SH wave has an extremely small press-in echo at a fitting portion of a wheel set as compared with an SV wave. FIG.
In the test example of the press-fit echo height with respect to the angle of refraction of the ultrasonic beam, (a) shows test conditions and (b) shows test results. In the test, a steel slab having a thickness of 10 mm was set on a steel plate having a width of 25 mm and a thickness of 40 mm by tightening it with a vice, and a press-fit echo was observed while changing the refraction angle from the ultrasonic probe. The measurement sensitivity was set to 80% + 10 dB with respect to a 1.0 mm slit provided on the bottom surface of a test piece having a thickness of 18 mm for both SV and SH. As shown in (b), in the case of the SV wave, the refraction angle is 3
In the range of 8 ° -60 °, the injection echo height is 20-40%
It is. The generation limit of the SV wave is 33.2 °.
In contrast, the SH wave has a refraction angle of 15 ° to 60 °,
The press-fit echo height is almost 0%.

It should be noted here that the SH wave can obtain high sensitivity and high accuracy in a region where the SV wave cannot be used and has a small refraction angle of 35 ° or less. As a result, in oblique flaw detection of a wheel set having a step portion that interferes with ultrasonic waves from the end face, the ultrasonic wave can reach the portion to be inspected immediately behind the step portion at a large incident angle. ) Can be reduced. Note that SH ultrasonic waves can be generated and used at a refraction angle of 0 ° to 90 °.

The present invention, which has been made to achieve the above-mentioned object based on this experimental finding, has an ultrasonic probe installed on the shaft end surface of a wheel set having a portion to be inspected on the outer peripheral surface, and the ultrasonic probe An ultrasonic wave is transmitted from the probe into the wheel axle toward the portion to be inspected, and the ultrasonic wave reflected from the material flaw of the portion to be inspected is received by the probe to detect the material flaw. In the ultrasonic flaw detection method, SH ultrasonic waves of a vibration type in which particles of a material vibrate in a direction perpendicular to the propagation axis of ultrasonic waves are transmitted from the ultrasonic probe, and are reflected (skipped) at least once on the outer peripheral surface. ), The refraction angle θ of the SH ultrasonic wave transmitted from the ultrasonic probe when the SH ultrasonic wave is incident at an incident angle α with respect to the normal to the surface of the inspected part is θ = 90
It is characterized in that the relationship is set to a degree-α.

Further, SH is introduced from the ultrasonic probe into the axle.
When transmitting the ultrasonic wave and causing the SH ultrasonic wave to reach the outer peripheral surface while skipping (reflecting) the S ultrasonic wave with respect to the normal to the surface of the inspected portion so that the inspected portion does not become a blind spot.
The incident angle α of the H ultrasonic wave is determined, the refraction angle θ of the SH ultrasonic wave sent into the wheel shaft is determined from the incident angle α, and the path W for converging the SH ultrasonic wave based on the refraction angle θ is determined. Then, the SH ultrasonic wave from the probe is transmitted at the refraction angle θ and converged on the path W.

When the path W is determined as the distance of the ultrasonic path from the ultrasonic probe to the part to be inspected, the ultrasonic wave from the probe converges at the distance W, that is, the ultrasonic wave Electronic control of the SH probe by the ultrasonic flaw detector is performed so as to converge.

The distance W of the convergence position can be determined by another method. That is, the ultrasonic wave transmitted from the probe at the shaft end face into the shaft at a refraction angle θ is once converged within a distance W after first passing over the axis of the wheel set having the radius R, and then converged to the portion to be inspected. The spread of the beam width of the arriving ultrasonic wave can be suppressed. According to the experimental confirmation by the present inventors, the distance W at this time is within R / 2.

An ultrasonic flaw detector to which the method of the present invention is applied is provided with an ultrasonic probe and an ultrasonic probe on a shaft end surface of a wheel set having a portion to be inspected on an outer peripheral surface. A probe driving device for rotating the shaft end surface in a circumferential direction, and when the ultrasonic probe is rotated, an ultrasonic wave is incident on a wheel axle, reflected from the portion to be inspected, and the probe is driven. In a wheel set ultrasonic flaw detector that detects the material flaws from ultrasonic waves received by a stylus, the probe driving device includes a gantry movable in the vertical direction and the longitudinal direction of the rim, and An installed rotating member, a positioning guide rod for fixing one end to the rotating member and inserting a tip end into a center hole of the shaft end face, and disposed in parallel outside the guide rod, One end is supported, and the other end holds the ultrasonic probe facing the shaft end face. A probe holding member, characterized in that the provided.

Thus, the positioning of the ultrasonic probe can be easily performed, and it is possible to easily and automatically detect the entire circumferential portion of the inspected portion of the wheel set from the same circumference of the end face of the wheel set.

The operation of the present invention will be described. Ultrasound involves a change in vibration mode, either greater or less, as it passes through or reflects off the interface where the two media meet. When the vibration mode A of the ultrasonic wave incident on the material from the ultrasonic probe and the vibration mode B of the ultrasonic wave reflected from the material flaw are different, the ultrasonic probe has low detection sensitivity for the vibration mode B,
This may cause a decrease in the detection sensitivity of flaws. In particular, when the light is reflected at a corner formed by a crack-like flaw opened on the surface of the material and the surface of the material, two reflections are involved, so that a remarkable vibration mode conversion occurs depending on the incident angle of the longitudinal ultrasonic wave. Causes a large decrease in sensitivity. However, in the SH ultrasonic wave, conversion of the vibration mode due to reflection hardly occurs, and the sensitivity decrease due to corner reflection is extremely small.

The longitudinal wave and the SV wave also change the vibration mode when passing through the fitting portion of the wheel set. For this reason, a part of the echo is received as a press-fit echo by the ultrasonic probe, which makes it difficult to identify a flaw generated in the fitting portion. However, SH
Since the ultrasonic wave has very little mode conversion accompanying the passage, almost no press-in echo is received as shown in FIG.
N, the inspection accuracy can be improved.

Further, since the SH ultrasonic wave can be used for oblique flaw detection from a low refraction angle, flaw detection over a wide range in the axial direction can be easily realized from the shaft end face. Also, when ultrasonic waves are obliquely incident from the shaft end face, the ultrasonic waves are blocked by the stepped portion of the shaft or the like, so that the ultrasonic waves cannot reach the target wheel fitting outer edge or the like. To avoid this, a skip method is used in which the ultrasonic beam incident from the shaft end surface is reflected at least once on the bearing surface and then propagated to the inspected portion. However, since SH has a small attenuation due to reflection on the outer peripheral surface, it is used. Since there is no reduction in sensitivity and the range of usable refraction angles is wide, it is easy to set flaw detection conditions, particularly, to continuously change settings.

[0023]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows an embodiment of an ultrasonic flaw detector applied to a vehicle wheel set. axle
A wheel shaft 100 in which a wheel 102 and a gear 103 are fitted to 101 is provided. The ultrasonic probe 21 is pressed against a shaft end face 105 of the wheel shaft 100, and an ultrasonic beam 210 is propagated in the axle 101. The ultrasonic beam 210 reaches the wheel fitting portion 108 and the gear fitting portion 109, and when there is a material flaw in those portions, it is received again by the ultrasonic probe 21 as a flaw echo, and the flaw is detected. Is detected.

The ultrasonic flaw detector 20 generates a pulsed voltage to excite the probe 21 to generate an ultrasonic wave, and at the same time, a reception signal generated when the probe 21 receives an ultrasonic echo. Is amplified and sent to the data recording processing device 40.

FIG. 3 shows a configuration diagram of the ultrasonic flaw detector. The ultrasonic flaw detector 20 of this embodiment is of an electronic scanning type. The trigger signal generated by the trigger signal generator 23 is transmitted to the transmission delay circuit 25
Then, the signal is divided into n trigger signals having different delay times. Here, the number n is the number of transducers 22 that constitute the ultrasonic probe 21. These n trigger signals are
Excites the pulse generator 24 so that the pulse generator 24
N pulse voltages each having a delay time are generated. These pulse voltages sequentially excite a plurality of transducers 22 constituting the ultrasonic probe 21.

FIG. 4 shows a schematic structure and operation of the electronic scanning ultrasonic probe. The probe 21 uses a shear vibration type shear wave vibrator, and the vibrators 22 are arranged in an array as shown in FIG. FIG. 2B shows a side view of the ultrasonic probe 21. The pulse generation timing of each oscillator is controlled by each delay element of the transmission delay circuit 25. As shown in (c), when the length of the delay time by the delay circuit 25 is qualitatively indicated, the wavefronts of the ultrasonic waves emitted from the respective oscillators 22 at different timings are synthesized and combined in an arbitrary direction (refraction angle). θ),
Further, an ultrasonic beam 210 converging at an arbitrary position (F) is formed.

The generation of SH ultrasonic waves and electronic scanning by a sliding vibration type vibrator are described in the aforementioned Japanese Patent Application H10-1433.
No. 46 (paragraphs 0012 to 0015 and FIGS. 2 to 4).

In the wheel flaw detection of this embodiment, SH ultrasonic waves are obliquely incident from the shaft end face. FIG. 5 is an explanatory diagram of the oblique flaw detection.
As shown in (a), when the wheel 102 is fitted to the wheel axle 101 and flaw detection is performed on the inside 111 of the wheel fitting portion, the probe 21 is installed at a predetermined position on the shaft end surface 105, and the ultrasonic beam is refracted at the refraction angle θ. The beam 210 is transmitted to converge the beam 210 to the target inspection region 111. At this time, since the SH ultrasonic wave has a large echo intensity from the flaw and a small press-in echo at the fitting portion, a high sensitivity and a high S
/ N oblique flaw detection becomes possible.

By the way, when flaw detection is performed on the inside 110 of the wheel fitting portion, the target inspection portion becomes a blind spot (dead zone) due to reflection at the step-off portion 107. At this time, as shown in (b), the ultrasonic wave is reflected on the cylindrical surface in front of the stepped portion 107, that is, the ultrasonic wave is focused on the target inspection region 110 by skipping the obstacle. The 1.0 skip method when converging to the target position by one reflection, the 1.5 skip method when two reflections are performed, 3
The number of times is referred to as the 2.0 skip method. In general, the longer the path of an ultrasonic beam, the greater the attenuation. Therefore, when flaw detection of a target portion can be performed with a different skip number, a smaller skip number is more desirable.

Propagation direction of ultrasonic beam to inspection site
(Refraction angle θ) and the beam path until the ultrasonic wave reaches the inspection site are determined by the ultrasonic flaw detector 20 according to an instruction from the control device 31.
Is controlled by electronic scanning. FIG. 6 shows a procedure for determining the refraction angle and the beam path by the control device. As shown in FIG.
The procedure will be described with reference to a geometrical illustration of the beam path by the 5-skip method.

When determining the refraction angle and the beam path, the control device 31 first sets the inspection site P3 (s101).
Specifically, the horizontal distance B from the shaft end face 105 where the probe 21 is installed to the inspection site P3 where the flaw 120 is present is shown.
give. Next, the incident angle α when the ultrasonic beam 210 is incident on the inspection portion P3 on the outer peripheral surface from the final reflection point (here, P2) is determined (s102). The incident angle α is an angle with respect to the normal line 211 of the outer peripheral surface P3.
It is more than the minimum angle (αmin) that can avoid the reflection at 107.

Next, the refraction angle θ is calculated from the incident angle α (s103). Assuming that the angle of refraction of the ultrasonic beam 210 at the incident point P0 (the angle with respect to the normal 212 of the shaft end face 105) is θ, the first reflection point P1 and the second reflection point P2 repeatedly reflect at an equal angle, and as a result, the refraction occurs. Angle θ = (90 degrees−incident angle α). That is, the refraction angle θ can be determined from the incident angle α of the final beam that can avoid the obstacle on the beam path to the inspection site P3.

Next, the skip number i is calculated from the refraction angle θ and the horizontal distance B (s103). The vertical projection distance of each of the points P0 and P1, the points P1 and P2, and the points P2 and P3 is A
1, A2, and A3 are fixed values based on the position of the probe 21 and the size of the wheel set 100, so that the refraction angle θ can be defined as in Equation 1.

[0034]

## EQU1 ## θ = tan の¹ (ΣAi / B) In the example of FIG. 7, i = 1 to 3, and ΣAi = A1 + A2 + A3.

Once the refraction angle θ has been obtained, the skip number i can be determined from the relationship of Equation 1. The calculation of the skip number i is not an essential procedure, and skip flaw detection is possible even if the skip number is unknown. Next, the beam path W is obtained from the horizontal distance B and the refraction angle θ by using Equation (2) (s105).

[0036]

## EQU2 ## From this, the convergence position of the ultrasonic beam by electronic scanning can be determined to be the path W.

When the control device 31 obtains the refraction angle θ and the beam path W with respect to the inspection site, it transmits them to the ultrasonic flaw detector 20. Upon receiving the refraction angle θ and the ultrasonic path W, the CPU (not shown) of the ultrasonic flaw detector 20 calculates the delay time of each transducer, and instructs the control terminal of the delay circuit 25 of the delay time.

The ultrasonic flaw detector 20 sets the delay circuit 25 to the refraction angle θ.
And the beam convergence position (inspection site P3) of the path W, a trigger signal is transmitted and the ultrasonic beam 21
0 is transmitted into the wheel set 100, and the beam 210 is focused on the inspection site P3. If the inspection site P3 has a flaw 120, the flaw echo propagates in the opposite direction along the beam path, is received by the probe 21, and is identified by the ultrasonic flaw detector 20. Thereafter, the probe driving device 30 rotates the probe 21 by a predetermined angle in the circumferential direction to perform a flaw detection over the entire circumference of the inspection region P3.

Next, when the position of the inspection part P3 is changed in the axial direction and in the direction in which the horizontal distance B increases, the incident angle α needs to be gradually smaller since the position P3 gradually becomes farther from the stepped portion 107. become. Therefore, if the change amount ΔB of the distance B and the change amount Δθ of the refraction angle θ are associated in advance, the inspection part can be adjusted by changing the refraction angle θ by Δθ. Thus, the entire inspection range of the outer peripheral surface of the axle 101 can be easily and automatically detected.

As described above, according to the ultrasonic inspection method for the wheel set according to the present embodiment, the refraction angle θ can be used from a small angle of about several tens of degrees, and the ultrasonic inspection by the stepped portion or the like is performed by the skip inspection from the shaft end surface. Since blind spots can be avoided, there is no need to disassemble the vehicle and perform flaw detection from the circumferential surface as in the related art, and the ultrasonic flaw detection test for the wheel set can be drastically rationalized.

FIG. 8 shows the structure of the probe driving device. The probe driving device 30 of the present embodiment is configured such that the ultrasonic probe 21
1 is set on a circle deviated from the center, and is turned intermittently several degrees on the circumference so that all the cylindrical surfaces of the axle 101 can be detected.

The ultrasonic probe 21 is held by a probe holder 320 composed of an air cylinder 33 and a probe holder 319.
It is pressed against the end face 105 of the axle 101. Shaft end face of probe 21
The radial position on 105 is determined with reference to guide rod 35 inserted into center hole 106 in the shaft end face. The contact surface between the shaft end face 105 and the ultrasonic probe 21 is coated with a couplant (not shown) for assisting the transmission of ultrasonic waves, and the probe 21 is pressed against the shaft end face 105 by the air cylinder 33. While
It is rotated by the electric motor 32 via the reduction gear 313 and the rotating shaft 34, and scans on the shaft end face.

The probe holder 320 and the electric motor 32 are fixedly mounted on the front-rear moving table 36. By turning the front-rear moving screw 37 with the front-rear moving handle 315, the probe 21 can be roughly positioned with respect to the shaft end face 105. Done. Front and rear carriage 36
Is mounted on an elevating table 38 connected by columns 316, and the elevating screw 39 is rotated by an elevating handle 314, thereby performing vertical alignment.

FIG. 9 shows an axle flaw detection procedure using the probe drive device. First, the guide rod 35 is inserted into the center hole 106 of the shaft end face, and the position of the ultrasonic probe 21 in the radial direction with respect to the shaft end face 25 is determined (s201). Next, a couplant is applied to the shaft end face (s202), and the probe 21 is pressed against the shaft end face 105 by operating the air cylinder 33 (s203).

Next, flaw detection conditions such as the set position of the probe 21 (turning angle at which inspection is stopped) and the horizontal distance (B) to the inspection site are set in the control device 31 (s204). As a result, the control device 31 obtains the refraction angle θ and the ultrasonic path W to the inspection site, and sets the electronic scanning condition (delay time of each element) of the ultrasonic probe 21 based on the θ and W.

Next, the flaw detection start switch 330 of the control device 31
To start flaw detection (s205). As a result, each transducer 22 of the array type ultrasonic probe sequentially excites according to the set delay time, and the refraction angle θ of the ultrasonic beam 210
While fixing or changing the convergence distance W, an ultrasonic wave is transmitted inside the shaft 101 (s206).

As a result, the ultrasonic echo reflected from the inside of the axis is received and detected by the probe 21, and data such as the direction of the probe, the beam path, and the ultrasonic echo height are recorded (s207). ). The recorded data is displayed in real time (s208). This is to monitor the progress of the flaw detection and the presence or absence of the detected flaw. For example, a C scope screen (a plane with the vertical axis representing the ultrasonic beam path and the horizontal axis representing the rotational scanning angle of the probe, A position where a flaw signal is detected is displayed on a developed view in which the axis is cut vertically.

Next, the electric motor 32 is driven to rotate the ultrasonic probe 21 by a predetermined angle around the center hole 106 of the shaft end surface 105 and stop (s209). And the above s
The processing from step 206 is repeated, and when the flaw detection up to the specified rotation angle is completed (s210), the processing ends. When the inspection part is moved in the axial direction, the refraction angle θ of the ultrasonic beam 210 is changed. Since the angle of refraction θ decreases as the distance from the stepping portion 107 decreases, the angle of refraction θ increases at predetermined intervals, for example, so that the inspection site can be changed.

As described above, while the conventional SV wave or longitudinal wave is reflected twice at the corner of the flaw and the sound pressure is greatly reduced, the present embodiment uses the SH ultrasonic wave vibrating parallel to the flaw detection surface. Utilizing the characteristic of the mode conversion that is small, high-accuracy ultrasonic flaw detection with little decrease in echo intensity was realized.

In particular, in the case of oblique flaw detection of the fitting portion of the axle from the shaft end face, the conventional ultrasonic wave cannot be used at a refraction angle of 35 ° or less, whereas the SH ultrasonic wave is refraction. It can be used at an angle of 35 ° or less, and has high latitude in setting the ultrasonic path and avoiding the dead zone. Furthermore, since the press-in echo from the fitting portion, which is a problem with longitudinal waves or SV waves, is extremely small, the accuracy of flaw identification can be greatly improved.

In this embodiment, an electronic scanning type ultrasonic probe is used, and the delay time of the excitation trigger of the SH transducers arranged in an array is set to the refraction angle and the ultrasonic path determined from the inspection site. Since the control can be arbitrarily performed according to this, efficient inspection can be performed.

In the above embodiment, the ultrasonic beam is converged to the total extension distance W of the ultrasonic path from the probe to the inspection site. However, according to another experimental knowledge, the convergence position when skip flaw detection is performed may not necessarily be the inspection part. That is, it was recognized that once the beam width was converged at a predetermined position along the ultrasonic beam path, the beam width at each skip point was sequentially narrowed.

FIG. 10 shows an embodiment using another convergence method. The illustrated example is a case in which the SH probe 21 is installed at a position deviated from the center on the center line of the shaft end face 105, and the material flaw 120 at the flaw detection site P3 is flawed by the 1.5 skip method. The ultrasonic beam is transmitted from the point P0 into the axle 101 at the refraction angle θ, reflected by the points P1 and P2, and reaches the point P3. in this case,
Before the beam incident from P0 first reflects beyond the central axis oo 'on the cylindrical surface (here, P1), the central axis o
A position F1 vertically within -1/2 of the axle radius R from -o '
However, once converged, the beam width reaching the inspection site P3 becomes smaller than the beam width at P0. That is, P0-P
Assuming that the beam width at each point of No. 3 is W0, W1, W2, W3, W0 ≧ W1 ≧ W2 ≧ W3, and the beam width becomes narrower each time reflection is repeated, and it is recognized that the beam is located at the inspection site. .

As described above, S incident obliquely from the shaft end face
Electronic scanning ultrasonic probe so that the H ultrasonic beam converges to a position within 1/2 of the axle radius perpendicular to the central axis before it first reflects off the cylindrical surface beyond the central axis. Set the child scanning conditions. According to this, since the convergence position of the beam can be fixedly handled regardless of the inspection site, only the refraction angle needs to be set as the control condition, and continuous testing of a wide range of inspection sites becomes easier.

[0055]

According to the present invention, the ultrasonic flaw detection of the fitting portion of the wheel set is performed by using the SH ultrasonic wave which can be used from a low refraction angle. Blind spots of sound waves can be greatly reduced, and flaw detection of all contact parts such as fitting parts from the shaft end face becomes possible, so that conventional flaw detection from the bearing surface becomes unnecessary, and inspection efficiency can be dramatically improved.

Also, since the SH ultrasonic wave has little change in the vibration mode due to reflection at the fitting member or the flaw, the attenuation of the ultrasonic intensity due to the application of the skip flaw detection is small, and the press-in echo at the fitting part is reduced. As it is greatly reduced compared to SV ultrasonic,
The flaw detection sensitivity and inspection accuracy can be greatly improved.

Further, the ultrasonic inspection apparatus for a wheel axle according to the present invention comprises: a positioning guide rod inserted into a center hole of the shaft end face;
A probe holding member disposed parallel to the outside of the guide rod, one end of which is supported by the rotating member and the other end of which holds the ultrasonic probe facing the shaft end face. In addition, the ultrasonic probe can be easily positioned, and the entire area in the circumferential direction of the inspected portion of the wheelset can be easily and automatically detected from the same circumference on the end face of the wheelset.

[Brief description of the drawings]

FIG. 1 is a block diagram of a wheel set flaw detector according to one embodiment of the present invention.

FIG. 2 is an explanatory diagram of a test example showing the superiority of SH ultrasonic waves used in the present invention.

FIG. 3 is a configuration diagram of an ultrasonic flaw detector.

FIG. 4 is an explanatory diagram showing a schematic structure and an operation principle of an electronic scanning SH ultrasonic probe.

FIG. 5 is an explanatory view showing a method of oblique flaw detection from an axle end face.

FIG. 6 is a processing flowchart for determining a refraction angle and a convergence position of an ultrasonic beam as an ultrasonic path for electronic scanning.

FIG. 7 is an explanatory diagram of an ultrasonic path for flaw detection of a fitting portion of an axle having a stepped portion.

FIG. 8 is a structural diagram of an ultrasonic probe driving device according to one embodiment.

FIG. 9 is a flowchart showing the procedure of an ultrasonic inspection test for a wheel set according to one embodiment.

FIG. 10 is an explanatory diagram showing a method of converging an ultrasonic beam according to another embodiment.

FIG. 11 is an explanatory view showing a conventional ultrasonic flaw detection method when a stepped portion is provided on an axle.

FIG. 12 is an explanatory view showing a state in which a train axle is disassembled for conventional ultrasonic testing.

FIG. 13 is an image diagram illustrating a vibration mode of an ultrasonic wave.

FIG. 14 is an explanatory diagram showing a test example of a sound pressure reciprocating passage rate at oblique incidence.

FIG. 15 is an explanatory diagram showing how the intensity of longitudinal ultrasonic waves is reduced.

[Explanation of symbols]

20: ultrasonic flaw detector, 21: ultrasonic probe, 22: vibrator,
23 ... trigger signal generator, 24 ... pulse generator, 25 ... transmission delay circuit, 26 ... reception delay circuit, 27 ... addition amplifier, 28 ... sweep signal generator, 29 ... display device, 30 ... probe drive device, 31…
Control device, 32: Electric motor, 33: Air cylinder, 34: Rotary shaft, 35: Guide rod, 36: Front / rear moving table, 37: Front / rear moving screw,
38: lifting table, 39: lifting screw, 40: data recording and processing device,
41… Recording device, 100… Wheel, 101… Axle, 102… Wheel, 103
... gear, 104 ... bearing surface, 105 ... shaft end surface, 106 ... center hole, 1
07: Step cutting part, 108: Wheel fitting part, 109: Gear fitting part, 21
0: Ultrasonic beam.

Continuing on the front page (72) Inventor Kozitsu Mitsue 3-2-1, Sachimachi, Hitachi-shi, Ibaraki Prefecture Within Hitachi Engineering Co., Ltd. (72) Inventor Osamu Kikuchi 3-2-1, Sachimachi, Hitachi-shi, Hitachi, Hitachi F term in Engineering Co., Ltd. (reference) 2G047 AA07 AC08 AD18 BB02 BC07 CB00 DB02 EA09 EA10 EA13 GA05 GB02 GB04

Claims (4)

[Claims] An ultrasonic probe is installed on a shaft end surface of a wheel set having a portion to be inspected on an outer peripheral surface, and ultrasonic waves are transmitted from the ultrasonic probe to the portion to be inspected within the wheel set, and In the wheel flaw detection method in which the probe receives ultrasonic waves reflected from the material flaws of the inspected part and detects the material flaws, particles of the material from the ultrasonic probe generate ultrasonic waves. Is transmitted at least once on the outer peripheral surface, and is reflected at a predetermined angle of incidence α with respect to the normal to the surface of the inspected portion. And the S
A method for detecting flaws on a wheel axle, wherein the angle of refraction θ of the SH ultrasonic waves transmitted from the ultrasonic probe when H ultrasonic waves are incident is set to a relation of θ = 90 degrees−α. . 2. An ultrasonic probe is installed on a shaft end surface of a wheel set having a part to be inspected on an outer peripheral surface, and ultrasonic waves are transmitted from the ultrasonic probe to the part to be inspected within the wheel set, and An ultrasonic flaw detection method for a wheel set in which the probe receives ultrasonic waves reflected from a material flaw of the inspected portion and detects the material flaw, wherein SH ultrasonic waves are introduced into the wheel set from the ultrasonic probe. And when the SH ultrasonic waves reach the outer peripheral surface while being skipped (reflected), the incident angle α of the SH ultrasonic waves with respect to the normal to the surface of the inspection target so that the inspection target does not become a blind spot.
Is determined from the angle of incidence α, the refraction angle θ of the SH ultrasonic wave transmitted into the wheel axle, a path W for converging the SH ultrasonic wave based on the refraction angle θ is determined, and And transmitting said SH ultrasonic wave at said refraction angle θ and converging it on a path W. 3. The method according to claim 1, wherein when the angle of refraction θ and the horizontal distance B between the probe and the part to be inspected are determined, the axial direction of the part to be inspected is changed by the angle of refraction. An ultrasonic flaw detection method for a wheel set, which is performed by changing θ. 4. An ultrasonic probe and an ultrasonic probe are installed on a shaft end surface of a wheel set having a portion to be inspected on an outer peripheral surface, and the probe is rotated in a circumferential direction of the shaft end surface. A probe driving device is provided, the ultrasonic probe is rotated, and an ultrasonic wave is incident on a wheel axis, reflected from a material flaw of the inspection target, and received by the probe. In the wheel flaw detection device for detecting the material flaw from the, the probe drive device, a gantry movable in the vertical direction and the longitudinal direction of the wheel axis, and a rotating member installed on the gantry, A positioning guide rod for fixing one end to a rotating member and inserting a tip into a center hole of the shaft end face, disposed in parallel outside the guide rod, one end supported by the rotating member and the other end A probe holding member for holding an ultrasonic probe in opposition to the shaft end face, and Ultrasonic flaw detector wheelsets to symptoms.