JPS6310524Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to an ultrasonic flaw detection device used for inspecting wheel axles of railway vehicles, and in particular, ultrasonic flaw detection of the entire wheel axle by varying the incident angle of ultrasonic waves incident from the end face of the wheel axle. This invention relates to an automatic ultrasonic flaw detection device that enables

Conventionally, this type of ultrasonic flaw detection involves ultrasonic flaw detection of the entire wheel set, so for the end face of the wheel set, a combination of vertical flaw detection and local flaw detection using longitudinal waves with a shallow refraction angle (approximately 7 to 22 degrees) is used. Furthermore, angle flaw detection is performed on the circumferential side of the shaft.

However, the end shape, wheel diameter, shaft length, etc. of the wheel set to be inspected vary depending on the type of vehicle. It requires a number of probes with different refraction angles adapted to the shape, and the flaw detection sensitivity also depends on the shape of the shaft to be inspected and the type of probe used.
There was a problem in that the sensitivity had to be adjusted to an appropriate level each time, taking into consideration beam path length, attenuation, etc.

The present invention was developed by focusing on these conventional problems, and allows flaw detection of the entire shaft by using a single probe and varying the angle of incidence from the shaft end, regardless of the shape of the wheel shaft. In addition, it is an object of the present invention to provide an apparatus that can perform flaw detection work more efficiently by uniquely determining flaw detection sensitivity according to the incident angle.

Hereinafter, the present invention will be explained based on the drawings.

FIG. 1 shows an example of an inspection facility for axles in which the ultrasonic automatic flaw detector of the present invention is used. On a stand 1, there are mounted driving friction wheels 3, 3' which are rotated at a predetermined number of revolutions by a motor 2. The driving friction wheels 3, 3' rotate axles 5 equipped with wheels 4.
The vibrator 6 is located at a position facing one end of the wheel set 5.
It is mounted on a movable mechanism 7 equipped with the incident angle adjustment mechanism of the present invention, which will be explained later, and this movable mechanism 7 is adjusted vertically and horizontally by a slider 9 attached to a post 8. In addition, 10 is an operation panel of the inspection equipment, and 11 is an ultrasonic flaw detector equipped with a cathode ray tube, a recorder, etc.

FIG. 2 is a sectional view showing one embodiment of the movable mechanism used in the present invention.

First, to explain the configuration, it consists of a variable angle mechanism section 12 and a variable angle probe section 13. First, the variable angle mechanism section 1
2 includes a DC motor 14 as a drive source, a decelerator 15 that decelerates the output circuit of the DC motor 14, an operating piece 18 that moves by rotation of the screw shaft 16 and operates the limit switches 17a and 17b, and a gear train. A potentiometer 19 is provided to detect the rotation angle of the probe.

On the other hand, the variable angle probe section 13 has a contact surface 20 on a contact plate 21 made of an acrylic plate or the like that is pressed against the shaft end.
The movable wedge 22 has a semi-cylindrical fixed wedge 20 with an exposed portion a, and a movable wedge 22 with a slidable vibrator 6 is provided on the outer circumferential surface 20b of the fixed wedge 20.
2 and the transducer 6 constitute an ultrasonic probe movable part. This movable wedge 22 is supported by a U-shaped support 23 via a spring 24.
3 has a fixed sector gear 25 indicated by a broken line,
The movable wedge 22 can be rotated along the outer peripheral surface 20b of the fixed wedge 20 by meshing with a worm 27 provided on the drive shaft 26 from the angle changing mechanism section 12.
The spring 28 is provided to suppress backlash caused by the meshing of the worm 27 and the sector gear 25.

The irradiation direction of the ultrasonic beam from the transducer 6 is set relative to the wheel shaft end surface so that when the vertical incidence angle shown in the figure is 0°, the rotation of the movable wedge 22 results in a predetermined angular range of +θ° to −θ°. The angle of incidence can be varied, and the light passes through a constant point of incidence P at any angle. The range of incident angle that can be adjusted varies depending on the shaft diameter, but is from +20° to
It is sufficient to set the angle to −20°.

Further, the inside of the variable angle probe section 13 in which the movable wedge 22 having the transducer 6 is provided is filled with oil to ensure that the ultrasonic beam propagates to the fixed wedge 20. There is.

FIG. 3 is a circuit block diagram showing an embodiment of the movable mechanism section 7 of FIG. 2 and its remote control device,
FIG. 4 shows a front view of the panel of the remote control device.

In FIG. 3, the remote control device 30 includes a DC
Servo amplifier 3 for driving and controlling the motor 14
1 and selected by switches S1, S2, S3, or S4, potentiometers P ₁ , P ₂ , P ₃
Alternatively, the angle setting command signal from _P4 is input as the reference signal _e1 , while the angle detection signal _e2 from the potentiometer 19 provided in the movable mechanism section 7 is input, and the servo amplifier 31 receives the angle detection signal. e ₂ is the reference signal e ₁
A drive signal is supplied to the DC motor 14 so that

On the other hand, as a means for displaying the incident angle of the vibrator 6 adjusted by the DC motor 14, an amplifier circuit 33 is provided which amplifies the angle detection signal _e1 from the potentiometer 19 and causes the incident angle indicator 32 to swing. .

In addition, the servo amplifier 31 receives power from the commercial power supply AC100V, and detects the angle detection signal _e2 as a positive or negative signal, so the potentiometer 1
9 is applied with voltages of +Vcc and -Vcc. Furthermore,
The forward and reverse rotation of the DC motor 14 is controlled by the servo amplifier 31.
This is done by switching the current direction by the oscillator 6.
When the rotation is out of a predetermined rotation angle range, the limit switch 17a or 17b is switched as shown by the broken line to forcibly stop the DC motor 14.

The vibrator 6 is connected to an ultrasonic flaw detector 35 by a cable 34, and this ultrasonic flaw detector 35
is provided with a sensitivity setting means for manually or automatically setting flaw detection sensitivity in accordance with selection of flaw detection distance by switches S1 to S4 of remote control device 30.

Next, to explain the operation panel of FIG. 4, the operation panel 40 includes a servo amplifier control panel section 40a.
and an incident angle setting panel 4b.The servo amplifier control panel section 40a has a known operation function, but the incident angle setting panel section 40b has the following circuit blocks corresponding to the circuit block shown in FIG. The operating section of potentiometers P ₁ to _{P 4} consisting of angle setting knobs (vernier dials) and switches S1 to S2
and an incident angle indicator 32.

Next, the operation of the present invention will be explained.

First, as a method of setting the incident angle of the vibrator 6 in the present invention, for example, as shown in FIG.
The wheel set 5 having the same diameter is divided into four equal parts with a predetermined length _l2 in the axial direction to determine flaw detection sections No. ₁ to No. ₄ . Set the angle of incidence.

This is based on the fact that the locations on the wheel set 5 where scratches are likely to occur are known empirically, and in reality, the wheel set 5 and wheels 4, which are easily damaged, are not divided equally as shown in Fig. 5. Connecting part (stress concentration part)
The angle of incidence is set by potentiometers P ₁ , P ₂ , P ₃ , and P ₄ so that the ultrasonic beam is directed toward 5 a , 5 b , 5 c , 5 d or the shaft metal 50 . For convenience, the following explanation is based on equal division No. 1~
This will be explained using No. 4 as an example.

For now, tentatively, for the flaw detection classifications No. 1 to No. 4, A
If we want to perform flaw detection on the circumference of the shaft shown at points A to D, the angle of incidence seen from the vibrator 6 through the incident point P for points A to D is immediately θ ₁ , θ ₂ , θ ₃ from the dimensional relationship shown in the figure. , θ ₄ (where θ ₁ >θ ₂ >θ ₃ >θ ₄ ) are determined, and therefore, the above-mentioned θ ₁ to θ ₄ are determined in advance based on the shape of the wheel set 5.

The incident angles θ ₁ to _{θ 4} thus obtained are set by potentiometers P ₁ to P ₄ shown in FIGS. 3 and 4, depending on the wheel set to be inspected.

Next, when the switches S1 to S4 are arbitrarily selected and closed in sequence, as is clear from the circuit block diagram of FIG.
The incident angle setting signals from the potentiometers _P1 to _P4 are input to the servo amplifier ₃₁ as a reference signal e1, and based on the input of this reference signal _e1 , the servo amplifier 31 drives the DC motor 14 to set the potentiometer. The vibrator 6 is moved in sliding contact with the fixed wedge 20 so that the angle detection signal e ₁ of the yometer 19 matches the reference signal e ₁ , and the DC motor 14 is stopped when e ₁ = e ₂ , and at this time,
The angle of incidence from the transducer 6 is determined by the potentiometer P ₁
The incident angle θ ₁ , θ ₂ , θ ₃ or θ ₄ is set at ~P ₄ , and each of points A to D of the wheel set 5 is inspected for flaws.

Next, the setting of flaw detection sensitivity when performing flaw detection by switching the incident angles θ ₁ to _{θ 4} as described above will be explained.

For now, let us assume that the average attenuation of the wheel set 5 is α (dB/
m), and the flaw detection sensitivity required for flaw detection at point D, which is the longest flaw detection distance, is β (dB), then the flaw detection sensitivity to make the distance amplitude characteristics the same for points A to D is as follows: Point A; β −(l ₁ + 2l ₂ )・α [dB] Point B; β−(l ₁ +l ₂ )・α [dB] Point C; β−l ₁・α [dB] Point D; β [dB]. Therefore, each of the flaw detection sensitivities of the above points A to D is set in the ultrasonic flaw detector 35 shown in FIG. 3, and the flaw detection sensitivity is switched automatically or manually in conjunction with each of the switches S1 to S4. By doing so, the flaw detection sensitivity can be determined uniquely.

In addition, with such a flaw detection sensitivity setting, the incident point P with respect to the wheel shaft end face remains constant even if the incident angle changes, so that the incident angle detection signal e ₂ from the potentiometer 19 that detects the incident angle of the vibrator 6 By performing gain control based on this, it is possible to automatically set the flaw detection sensitivity according to the incident angle.

That is, as shown in Fig. 5, if the distance from the point of incidence P to the circumference of the wheel is _l3 , then the distance _lx from the point of incidence P to the circumferential side of the wheel axle 5 is _lx = _l3 /cosθ. Therefore, the flaw detection sensitivity αx is αx=β−(l ₃ /cosθ)・α, and since α, β, and l ₃ are constants, the flaw detection sensitivity αx can be automatically set according to the incident angle θ. Specifically, an AGC circuit having the gain control characteristic of the above formula based on the incident angle detection signal e ₂ may be used.

The above incident point P is located at the center of the wheel shaft end face.
A center hole is provided for shaft machining, so
Normally, the position is offset by about 30 mm from the center of the axis.

As explained above, according to the present invention, by providing a semi-cylindrical fixing wedge that presses against the end surface of the wheel axle, and sliding the vibrator on the circumferential surface of this fixing wedge,
By keeping the incident point on the wheel set end face constant and changing the incident angle, it is now possible to perform ultrasonic flaw detection on the entire wheel set using a single transducer, and even if the wheel set has a different shape, the same transducer can be used. Since it can be used as is, there is no need for multiple different transducers depending on the shape of the wheel axle.Furthermore, the flaw detection sensitivity is uniquely determined depending on the angle of incidence of the probe, so the flaw detection waveform etc. can be changed each time. There is no need to adjust the flaw detection sensitivity while looking at the flaw detection, the flaw detection work on the wheel set becomes simple and easy, and the efficiency of the inspection work can be greatly improved.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram showing the wheel set inspection equipment, Figure 2
The figure is a sectional view showing an embodiment of the movable mechanism of the present invention, Fig. 3 is a circuit block diagram showing an embodiment of the remote control device of the present invention, and Fig. 4 is a diagram of the operation panel of the remote control device. FIG. 5 is a front view showing one embodiment, and is an explanatory view showing divided flaw detection of a wheel set according to the present invention. DESCRIPTION OF SYMBOLS 1... Frame, 2... Motor, 3, 3'... Drive friction wheel, 4... Wheel, 5... Wheel shaft, 6... Vibrator, 7... Movable mechanism section, 8... Post, 9... ... Slider, 10 ... Operation panel, 11, 35 ... Ultrasonic flaw detection device, 12 ... Angle angle mechanism section, 13 ... Variable angle probe section, 14 ... DC motor, 15 ... Decelerator,
16... Screw shaft, 17a, 17b... Limit switch, 18... Movable piece, 19... Potentiometer, 20... Fixed wedge, 20a... Contact surface, 20b... Circumferential surface, 21... Contact plate , 22...
... Movable wedge, 23 ... Support body, 24, 28 ... Spring, 25 ... Sector gear, 26 ... Drive shaft,
27...Worm, 30...Remote control device, 31
... Servo amplifier, 32 ... Incident angle indicator, 3
3...Amplification circuit, 34...Cable, 40...Operation panel, 40b...Incidence angle setting panel section, 4
0a...Servo amplifier operation panel section, 50...Shaft metal, _P1 to _P4 ...Potentiometer (for setting angle of incidence), S1 to S4...Switch.

Claims (1)

[Claims for Utility Model Registration] (1) A wedge that is slidably provided on the outer peripheral surface of a semi-cylindrical fixed wedge that is pressed against the shaft end surface of a wheel set that rotates at a constant speed, and that passes through a fixed incident point on the shaft end surface. An ultrasonic probe movable section consisting of a movable wedge and a vibrator that injects ultrasonic waves into the wheel axle, and the ultrasonic probe movable section is rotated on the outer circumferential surface of the fixed wedge based on an incident angle setting command. an incident angle adjusting mechanism that adjusts the incident angle with respect to a fixed incident point to a command angle value by moving the incident angle, and a sensitivity setting means that sets a flaw detection sensitivity with respect to a flaw detection distance based on the incident angle adjusted by the incident angle adjusting mechanism. Automatic ultrasonic flaw detection equipment for wheel sets. (2) The ultrasonic automatic wheel set according to claim 1, wherein the sensitivity setting means sets the flaw detection sensitivity for each predetermined division divided in the axial direction of the wheel set. Flaw detection equipment.