JP2691822B2 - Method for bevel flaw detection of boring axle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bevel flaw detection method for boring axles used in railway vehicles, and more specifically, to spirally scan the inner surface of the boring axle by ultrasonic bevel flaw detection. The present invention relates to a method for separating an internal defect echo and a press-fit echo at a portion where a press-fit echo is likely to occur in a fitting portion such as a wheel seat when performing flaw detection by.

[0002]

2. Description of the Related Art Conventionally, ultrasonic testing has been performed in an alternation test of an axle holding wheels provided in a railway vehicle. Particularly in the case of a boring axle, a flaw running in the circumferential direction on the axle surface is apt to be formed. To detect only this flaw, it is necessary to set a flaw detection gate near the axle surface. This is because wheels are fitted on the outside of the axle, so if you do not set the gate, ultrasonic waves will enter the inside of this wheel from the axle and the probe will pick up the ultrasonic waves reflected inside the wheel. This is because it is difficult to detect the defect echo inside the essential axle. However, regarding the echo inside the axle, the axle is
It is a forged part because it is a part that requires strength and undergoes bending bending fatigue. Therefore, the metal structure is also fine, and normally, there is no echo from the inner surface or the outer surface of the axle itself. If there is such an echo, it is a defective echo present at such a position and should be detected as harmful.

[0003]

However, in ultrasonic flaw detection of an axle, a press fit echo is generated, for example, during internal flaw detection of a fitting portion of a wheel of an axle, and the press fit echo is picked up by setting a gate. As a result, the actual detection of the defective echo is made difficult. The press-fit echo is an echo that is not related to scratches caused by the wheel being press-fitted to the axle in this case. Since this press-fit echo is generated at the wheel press-fitting site, which is the site where most of the fatigue scratches occur, it was a major obstacle in ultrasonic flaw detection. The cause of this press-fit echo has been tested several times in the past, but it has not yet been clarified. At present, it is considered that some phenomena overlap and cause the occurrence. Even when flaw detection is performed on the boring axle from the inside, the presence of the press-fit echo makes it difficult to detect the defect echo. An object of the present invention is to solve the above problems.

[0004]

According to a first aspect of the present invention, there is provided an oblique angle flaw detection method for a boring wheel axle, wherein an inside of the boring wheel axle 100 has a boring portion inside 103, and an axle member 100 to which a fitting member is fitted is fitted. The flaw detection gate G is set at the fitting position of 1 and the ultrasonic probes 1a and 1b are spirally scanned to perform flaw detection from the inside of the axle 100, and the following means are adopted. It is a thing. That is, at the time of flaw detection inside the fitting portion 102 of the axle 100, the presence or absence of harmful defects is determined by observing the presence or absence of echo at the outer edge of the set range of the flaw detection gate G. Here, the "detection gate" is an area that is set to narrow down the area that eliminates unnecessary echo and detects the echo that requires inspection, and the "outer edge" is within the area of the "detection gate." ,
In addition, it refers to the vicinity of the boundary that separates the gate setting area from the other areas. A beveled flaw detection method for a boring axle according to a second aspect of the present invention is to install a flaw detection gate G at the fitting position of the axle 100 in which the fitting member is fitted, inside the boring portion interior 103 of the boring axle 100. Set the ultrasonic probe 1a, 1b
It is characterized in that the axle 100 is flaw-detected from the inside by scanning in a spiral shape, and the following means are adopted. That is, at the time of flaw detection inside the fitting portion of the axle 100, at the outer edge of the setting range of the flaw detection gate G at the fitting position of the axle 100, the peak of the strength of flaw detection echo in the circumferential direction of the axle 100 is harmful. Determine the presence or absence of defects. A bevel angle flaw detection method for a boring axle according to a third aspect of the present invention is directed to the inside 10 of the boring portion of the boring axle 100.
3, the flaw detection gate G is set at the fitting position of the axle 100 in which the fitted member is fitted, and the ultrasonic probe 1
By scanning a and 1b in a spiral fashion, the axle 1
00 is detected from the inside,
The following means are adopted. That is, at the time of flaw detection inside the fitting portion of the axle 100, the strength of flaw detection echo in the circumferential direction of the axle 100 is detected at the outer edge of the setting range of the flaw detection gate G at the fitting position of the axle 100, and it is determined as a harmful defect. The width of the echo is examined only for the echo that has reached a certain level to determine the presence or absence of harmful defects. A bevel angle flaw detection method for a boring axle according to a fourth aspect of the present invention is to install a flaw detection gate G at the fitting position of the axle 100 in which the mating member is fitted in the boring portion interior 103 of the boring axle 100. Set,
The ultrasonic probe 1a, 1b is spirally scanned to detect the flaw in the axle 100 from the inside, and the following means are adopted. That is, at the time of flaw detection inside the fitting portion of the axle 100, at the outer edge of the setting range of the flaw detection gate G at the fitting position of the axle 100,
The width of the flaw detection echo in the circumferential direction of the axle 100 is checked to determine the presence or absence of harmful defects.

[0005]

[Operation] At the time of ultrasonic flaw detection of the boring axle, at the set outer edge of the flaw detection gate, without being disturbed by the press fit echo,
It has been discovered by the applicant that the waveform of the defective echo is detected. Therefore, by adopting the bevel flaw detection method for the boring axle according to the first aspect of the present invention, that is, by detecting the echo at the outer edge of the flaw detection gate at the time of flaw detection of the fitting portion of the axle, the press fit echo is detected. It became possible to distinguish between the defect echo and. That is, as described above, the “flaw detection gate” is an area set to eliminate unnecessary echoes and narrow the area for detecting echoes that require flaw detection, and within the range in which the “flaw detection gate” is set. It is possible to detect the echo with, but conventionally, the central part of the gate of the "flaw detection gate" is traditionally considered to be suitable for detecting the defect echo,
Even inside the "flaw detection gate", the outer edge thereof, that is, the vicinity of the boundary dividing the inside and the outside of the gate, was not used for detecting the defect echo. The first invention of the present application has found that such an outer edge is an extremely useful region for distinguishing the echo, and made it possible to distinguish between the press-fit echo and the defective echo. Further, in the method for oblique-angle flaw detection of the boring axle according to the second aspect of the present invention, in the ultrasonic flaw detection inspection of the boring axle, the press-fit echo causes noise with small signal intensity at the front outer edge of the flaw detection gate in the longitudinal direction of the axle. Since the defect echo is detected as a waveform with a large signal strength, by adopting the above-mentioned means, that is, at the time of flaw detection inside the fitting portion of the axle, the outer edge of the flaw detection gate in the longitudinal direction of the axle is detected. By detecting the echo in (1), the press-fit echo and the defective echo can be more reliably discriminated. Furthermore, the bevel flaw detection method for the boring axle according to the third aspect of the present invention determines whether the detected echo is an echo that reaches a certain level at the outer edge of the flaw detection gate, and is likely to normally exist at the fitting position. By utilizing the property that the scratch has a width in the circumferential direction of the shaft, it is possible to discriminate whether or not the echo has a width in the circumferential direction of the shaft, and it is possible to judge with an extremely high probability. Furthermore, the bevel flaw detection method for the boring wheel shaft according to the fourth aspect of the present invention utilizes the property that the flaw that is likely to be present at the fitting position usually has a width in the circumferential direction of the shaft, and therefore, at the outer edge of the flaw detection gate. ,
By distinguishing whether or not the echo has a width in the axial direction, it is possible to judge with extremely high probability.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below with reference to the drawings. FIG. 1 shows an example of an apparatus most suitable for carrying out the present invention. Taking the boring axle 100 in which the wheels 101 are press-fitted as an example, the probe holder 2 is arranged inside the axle from one end of the axle 100. The probe holder 2 is provided at one end of the flexible tube 4. The flexible tube 4 has a length that can sufficiently follow the probe holder 2 regardless of the position inside the axle 100.

The other end of the flexible tube 4
It is connected to a winding means 5 such as a pulley provided outside the axle. Reference numeral 40 denotes a pulley for changing the sliding direction of the flexible tube 4. By winding the flexible tube 4 by the winding means 5, the probe holder 2 moves to the right side in FIG. 1, and by unwinding the flexible tube 4, the probe holder 2 Move to the left of 1. The flexible tube 4 is disposed so as to be inserted through the axle mounting portion 7. The axle mounting section 7 is fixed to an end of the axle 100 and includes a position sensor 70 that detects a sliding position of the flexible tube 4 and obtains information on a flaw detection position. In the winding means 5, the rearmost end of the flexible tube 4 is connected to the probe rotating means 3 such as a rotating motor. To be more precise, a rear end of a flexible shaft 41 described later is connected to the rotating means 3. As long as the winding means 5 is provided with a moving means such as a caster 50 for easy movement, the installation position can be quickly moved according to the working environment, regardless of the weight of the apparatus, and the winding means 5 is convenient. is there.

The flexible tube 4 itself is internally provided with wiring for transmitting information sent from the ultrasonic probes 1a and 1b and the probe holder 2, and the winding means 5 The information is transferred to the flaw detector 8 and the computer 9. Depending on the data processing, it is also possible to connect and execute a printer 110 for printing out the stored data or the data obtained in real time.

The configuration of the probe holder 2 will be described with reference to FIG. The rear part of the probe holder 2 is connected to the distal end side of the flexible tube 4, and the front part has
A rotary head unit 10 provided with ultrasonic probes 1a and 1b for oblique flaw detection is connected.

The rotary head unit 10 includes a rotary connector 12 provided inside the probe holder 2 via a shaft 13.
It is rotatably fixed to the shaft. Rotary connector 1
2 itself transmits a signal from the rotary head 10. The outside of the shaft 13 is placed so as to be included in a tubular body 14 fixed directly to the rotary head unit 10.
The tubular body 14 is provided with an oil supply pipe 15 serving as an ultrasonic medium for the ultrasonic probes 1 a and 1 b inside, and is connected to an oil supply pipe 16 of the probe holder 2. This connection
This is performed by incorporating a rotary joint (not shown).
A gear 44 is provided outside the rear of the tubular body 14.

In the rear inside of the probe holder 2, a flexible shaft 4 contained in a flexible tube 4 is provided.
A gear 42 is provided for connection to the gear 1. This gear 42
Is rotated by receiving the rotation of the flexible shaft 41 rotated by the rotation of the rotation motor 3, and is fixed to the rotation position detector 6 provided in the probe holder 2. The rotation of the gear 42 is performed at both ends by the gear 42 and the gear 4
4 through a shaft 43 provided with gears that engage
The power is transmitted to the gear 44. As a result, the rotary head 10 rotates in response to the rotation of the rotary motor 3.

The rotary head unit 10 is fixed with two ultrasonic probes 1a and 1b back to back. 1
Reference numeral 1 denotes a signal line for sending detection signals obtained by the probes 1a and 1b to the flaw detector 8 via the flexible tube 4.

The two ultrasonic probes 1a and 1b are fixed to the rotary head 10 such that their directions face the inner peripheral surface of the boring portion of the axle 100, respectively. A spike 18 is provided between the probes 1a and 1b, and the probes 1a and 1b are provided.
Are urged toward the inner peripheral surface of the boring portion of the axle 100, respectively. A metal fitting for fixing the flexible tube 4 to the probe holder 2 is provided with an axial position detection wire 17.

When a probe is scanned spirally in a direction indicated by an arrow Z in FIG. 2 using such a device, the rotation of the rotary motor 3 causes the rotary head 10 to rotate in the direction of the arrow Y. By the unwinding operation of the flexible tube 4 by the winding means 5, the flexible tube 4 is slid to transfer the rotary head unit 10 together with the probe holder 2 in the X direction. Thereby, the inside of the boring axle 100 can be spirally flawed from inside. When the flaw detection is performed in the direction opposite to the arrow Z, the rotating head unit 10 is transferred together with the probe holder 2 in the direction opposite to the X direction by the winding operation of the winding unit 5. At this time, if necessary, if the rotating motor is rotated in the direction opposite to the above, and the rotating head unit 10 is rotated in the direction opposite to the arrow Y, the spiral scanning can be completely performed in the opposite direction. However,
In order to ensure the scanning, the probe holder 2 and the rotary head unit 1 are moved in the direction opposite to the X direction in the case of normal scanning, that is, in the direction in which the winding unit 5 moves by the winding operation.
It is preferable to carry out flaw detection by transferring 0.

The ranges of the beams of the oblique probes 1a and 1b are as shown by hatched portions V and W in FIG.
Will be described in detail). Further, at the time of flaw detection, the computer 9 described above scans the probe, operates the flaw detector 8, calibrates the sensitivity, processes flaw detection data, determines and outputs flaw detection results (e.g., launches the printer 110 or monitors the computer 9). By performing control such as image output), it is possible to completely automate flaw detection.

By using an apparatus as described above,
Inside the boring axle, it is no longer necessary for the inspector to operate a bulky flaw detector near the axle, and the ultrasonic probe is automatically scanned without being affected by the operating environment outside the axle. You can

Next, a method according to the present invention which is carried out by using such an apparatus will be described. First, the echo in ultrasonic flaw detection on the boring axle will be described.

Reference numeral 102 in FIG. 3 denotes a fitting portion, that is, a portion where the above-mentioned wheels 101, 101 are press-fitted (hereinafter referred to as a press-fitting portion 102). Reference numeral 103 indicates a hollow portion of the boring wheel shaft 100. The beam V emitted from the ultrasonic probe 1a has a direction in which the vicinity of the left corner A of the axle 100 can be detected. On the contrary, the beam W emitted by the ultrasonic probe 1b has a directionality capable of flaw detection near the right corner B of the axle 100. The two ultrasonic probes 1a and 1b have the same function and configuration.

Now, the case where the ultrasonic probe 1b detects a flaw in the press-fitting portion 102 of the wheel 101 on the right side of FIG. 3 will be described as an example. The ultrasonic probe 1b moves in a spiral shape, but here, according to the displacement of the ultrasonic probe 1b in the longitudinal direction of the axle, that is, in the direction of arrow E shown in FIG. 4 of the ultrasonic probe 1b. Consider the resulting echo according to the moving component to. As shown in FIG. 4, the beam W emitted by the ultrasonic probe 1b is
It spreads with the range shown in Wb.

The position Ga in the press-fit portion 102 shown in FIG.
That is, the echo obtained when the flaw detection gate G is set at the reflection position in the press-fitting portion 102 of the central beam Wa has a poor S / N ratio (low) as shown in FIG. , The defect echo H is blocked from being detected by the press fit echo J. 5 and 6, the vertical axis represents the height (dB) of the reflected echo, and the horizontal axis represents the displacement in the axle longitudinal direction E.

The locus when the ultrasonic probe 1b is moved in the longitudinal direction of the axle, that is, the E direction in FIG. 4, will be described with reference to FIG. In FIG. 6, Gt indicates the central region of the gate G, which has been conventionally exclusively used for flaw detection.
A region outside the central region Gt within the setting range of the gate G is called an outer edge. As shown in FIG. 6, the moving defect echo H appears as a defect echo Ha at the front outer edge D of the flaw detection gate G (outer edge on the left-hand side of the central region Gt), and the beam W of the beam W appears at the rear outer edge of the flaw detection gate G. Due to the spread Wb, it is detected as a defect echo Hb. Hx in FIG. 6 indicates the movement trajectory of the defect echo H. Further, at the position C, the defect echo H has the central beam Wa
Appears as the maximum echo Hp of the defect.

Due to the above-mentioned spread Wb of the beam W, the front outer edge D of the press fit echo J (the gate G where the defect echo Hb is generated)
The outer edge on the right side of the central region Gt in FIG. 6, the path length of the beam is long, and miscellaneous echoes from distant positions on the outer side may be mixed.
The position discrimination is more appropriate. ) And the position of the defect C due to the movement in the axle circumferential direction F shown in FIG. 7 at the position C, the waveforms shown in FIGS. 8 and 9 are obtained. 8 shows a waveform due to displacement in the circumferential direction of the axle at the position C, and FIG. 9 shows a waveform due to displacement in the circumferential direction of the axle at the front outer edge D position. The vertical axis Ky in FIGS. 8 and 9 is
The height of the echo is shown, and the horizontal axis Kx shows the displacement angle with respect to the circumferential direction of the axle.

The defect echo H has a defect L as shown in FIG.
The width in the circumferential direction and the spread Wb of the beam W shown in FIG. 4 appear as a width in FIGS. 8 and 9. As shown in FIG. 8, at the position C, the press-fit echo is also detected as being continuous in the circumferential direction.

However, as shown in FIG. 9, at the front outer edge D position, detection is performed with a constant signal intensity.
Only the defect echo H is detected, and the press fit echo J is detected as noise having a weak signal intensity. Therefore, for example, in FIG.
By excluding the second echo from the right from the above as a weak one, the probability of defective echo detection can be increased and its accuracy can be improved. The reason why the press-fit echo becomes a weak signal has not been clarified in detail, but at present, the press-fit echo is used outside the center region of the gate, which is the front outer edge D position of the flaw detection gate, using the end of the beam W. It is considered that since the echo is detected, the probability that the press-fit echo is generated is reduced.

Particularly when the member to be fitted is the above-mentioned wheel, since the flaw to be detected has a width in the circumferential direction of the axle, at the front outer edge D position shown in FIG.
That is, by performing flaw detection using the end of the beam W and examining the width of the echo in the circumferential direction of the axle, the defect echo and the press-fit echo for such a flaw can be separated with higher accuracy.

As an appropriate example of such separation, as shown in FIG. 10, the detection level is set to two stages, and the defect recognition level Ra for detecting a defect echo of a size that is a harmful defect and the echo. The defect echo and the press fit echo are discriminated by the monitoring level Rb for checking the width. More specifically, the echo width is checked for the level Rb only for the echo exceeding the level Ra. For example, even if a defect echo does not exceed the level Ra, it is not regarded as a harmful defect and is ignored.
Only for those exceeding the range, the presence or absence of the width of Kx, that is, the defect echo or the press-fit echo is determined. Specifically, in the state shown in FIG. 10, the echoes other than the first to third echoes from the left and the sixth and eighth echoes are at the level R.
a and exclude these echoes by level R
The width of the echo can be checked at b, and the third echo from the left, which has a width, can be determined as a defective echo. With such an implementation, extremely highly accurate determination can be performed.

[0027]

According to the first invention of the present application, when ultrasonic flaw detection is performed from the inner surface of the boring axle by ultrasonic scanning for flaws on the axle, a press-fit echo at a fitting portion such as a wheel seat is generated. This makes it possible to reliably separate the defect echo and the press-fit echo at a portion that is likely to occur, which is effective in improving the accuracy of defect detection and the ease of discrimination. According to the second invention of the present application, when ultrasonic flaw detection is performed from the inner surface of the boring axle by ultrasonic scanning for flaws on the axle, a press-fit echo at a fitting portion between the axle and the wheel such as a wheel seat is generated. The defect echo and the press-fit echo can be more reliably separated at a site that is likely to occur, and the accuracy of detection of a defect that is likely to exist at such a site is significantly improved. According to the third invention of the present application, the defect echo and the press-fit echo at the fitting portion between the axle and the wheel can be more reliably separated. Similarly, according to the fourth aspect of the present invention, the defect echo and the press-fit echo at the fitting portion of the axle and the wheel can be more reliably separated.

[Brief description of the drawings]

FIG. 1 is a schematic overall front view of an apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic sectional view of a main part of the apparatus according to the embodiment of the present invention.

FIG. 3 is an explanatory diagram showing a flaw detection state according to the present invention.

FIG. 4 is an explanatory view of a main part showing a flaw detection state according to the present invention.

FIG. 5 is an explanatory diagram showing a waveform obtained by flaw detection according to the present invention.

FIG. 6 is an explanatory diagram showing a waveform obtained by flaw detection according to the present invention.

FIG. 7 is an explanatory view of a main part showing a flaw detection state according to the present invention.

FIG. 8 is an explanatory diagram showing a waveform obtained by flaw detection according to the present invention.

FIG. 9 is an explanatory diagram showing a waveform obtained by flaw detection according to the present invention.

FIG. 10 is an explanatory diagram showing an example of waveform discrimination according to the present invention.

[Explanation of symbols]

 1a, 1b Ultrasonic probe 2 Probe holder 3 Probe rotating means 4 Flexible tube 5 Winding means 6 Rotational position detector 100 Axle 102 Press-fit section 103 Hollow section

Claims (4)

(57) [Claims] 1. Inside the boring part of the boring axle,
The flaw detection gate is set at the fitting position of the axle on which the member to be fitted is fitted, and the ultrasonic probe is spirally scanned to detect the flaw from the inside of the boring axle. In the angular flaw detection method, when flaw detection is performed inside the fitting portion of the axle, the presence or absence of harmful defects is determined by observing the presence or absence of echo at the outer edge of the setting range of the flaw detection gate. Bevel flaw detection method for boring axle. 2. Inside the boring portion of the boring axle,
The flaw detection gate is set at the fitting position of the axle on which the member to be fitted is fitted, and the ultrasonic probe is spirally scanned to detect the flaw from the inside of the boring axle. In the angular flaw detection method, during flaw detection inside the axle fitting part, at the outer edge of the setting range of the flaw detection gate at the axle fitting position, due to the height of the peak of echo flaw detection in the circumferential direction of the axle, harmful defects A bevel flaw detection method for a boring axle, which is characterized by determining the presence or absence of 3. Inside the boring portion of the boring axle,
The flaw detection gate is set at the fitting position of the axle on which the member to be fitted is fitted, and the ultrasonic probe is spirally scanned to detect the flaw from the inside of the boring axle. In the angular flaw detection method, when flaw detection is performed inside the axle fitting area, the strength of the flaw detection echo in the axle circumferential direction is detected at the outer edge of the setting range of the flaw detection gate at the axle fitting position, resulting in a harmful defect. A bevel flaw detection method for boring axles, characterized in that only the echoes that have reached a level are examined for the echo width to determine the presence or absence of harmful defects. 4. Inside the boring portion of the boring axle,
The flaw detection gate is set at the fitting position of the axle on which the member to be fitted is fitted, and the ultrasonic probe is spirally scanned to detect the flaw from the inside of the boring axle. In the angular flaw detection method, when performing flaw detection inside the axle fitting area, check the width of the flaw echo in the circumferential direction of the axle at the outer edge of the setting range of the flaw detection gate at the axle fitting position to check for the presence of harmful defects. A bevel flaw detection method for boring axles, which is characterized by being distinguished.