JP2002082100A - Ultrasonic flaw detector for bored shaft - Google Patents

Abstract

PROBLEM TO BE SOLVED: To dispense with the separate execution of an oil recovering work after the end of a flaw detection. SOLUTION: After a flaw detecting head 11 is inserted to the inner part 2a of a bored shaft 2 to lay a seal area S in a closed space, the seal area S is filled with oil. The sealing property and oil feeding and sucking quantities of both oil seals 18 and 19 are set so that the supply and suction of oil are well-balanced by the leak of oil from the seal area S to always fill the seal area S with the oil in the axial movement of the head 11 within the inner part 2a of the bored shaft 2. Since the feeding resistance is minimized by leaking the oil from the seal area S, the movement of the head 11 is smoothed. Further, since the leaked oil is sucked by a secondary discharge passage so as not to be left, it is not necessary to separately execute the oil recovering work after the end of flaw detection.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic flaw detector used for railway vehicles and the like, which detects a hollow boring shaft with ultrasonic waves.

[0002]

2. Description of the Related Art A hollow shaft having a hollow inside is used for the axle of a Shinkansen railway vehicle from the viewpoint of weight reduction and the like. The boring shaft may be damaged along the shaft circumferential direction on the shaft surface as the vehicle travels. For this reason, the boring shaft is inspected for damage at the alternation inspection for each predetermined traveling distance, and if there is a flaw, the boring shaft is replaced by restricting train operation etc. I have.

Conventionally, such an ultrasonic flaw detector for detecting a boring axis with an ultrasonic wave is disclosed in Japanese Unexamined Patent Publication No. 6-2655.
The one disclosed in Japanese Patent Publication No. 28 is known. As shown in FIGS. 6 (a) and 6 (b), this ultrasonic flaw detection apparatus has a flaw detection head 101 capable of moving along the axial direction inside 2a of a boring shaft 2 in which wheels 1 are fitted on both left and right sides. And an oil supply passage 102 for supplying oil to the inside 2a of the boring shaft 2.
And two ultrasonic transducers 103 arranged back to back around the central axis of the flaw detection head 101, and a rotary motor 104a for rotating the flaw detection head 101 axially.
And a computer 105 for outputting flaw detection results and the like.

[0004] The flaw detection head 101 is movable in the axial direction by unwinding or winding up the flexible tube 106. Further, the rotation motor 104a
Although connected to the end of the flexible tube 106, when the rotation shaft 104b (inserted into the flexible tube 106) is rotationally driven by the rotation motor 104a, the rotation is transmitted to various gears 1.
04c is transmitted to the flaw detection head 101, and the flaw detection head 101 rotates.

When the boring shaft 2 is to be flaw-detected using this ultrasonic flaw detector, oil is supplied from an oil supply passage 102 to fill the inside 2a of the boring shaft 2 with oil, and the flaw detection head 101 is floated on the oil. The rotating motor 104
The rotation of the flexible shaft 104b and the gear 1
The flaw detection head 101 is moved in the axial direction by an unwinding operation or a winding operation of the flexible tube 106 while rotating the flaw detection head 101 via the portion 04c. As a result, the ultrasonic vibrator 103 is moved to the inside 2 a of the boring shaft 2.
Is inspected spirally from the inside.

[0006]

In the above-described ultrasonic flaw detector, a large amount of oil remains in the inside 2a of the boring shaft 2 after the flaw detection inspection because the flaw detection head 101 is flawed while being floated on oil. I do. If you leave this as it is,
The remaining oil may penetrate the bearing and mix with the lubricant, and the lubricant may not exhibit its original performance. For this reason, at present, a large amount of oil remaining after the end of the flaw detection inspection is collected by a collector other than the inspector using the suction device. As described above, in the conventional ultrasonic testing, there is a problem that it is difficult to say that the working efficiency is good.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems, and an object of the present invention is to provide an ultrasonic flaw detector which does not require separate oil recovery after the flaw detection inspection is completed.

[0008]

Means for Solving the Problems and Effects of the Invention In order to solve the above problems, the present invention relates to an ultrasonic flaw detector for flaw detection of a hollow boring shaft having a hollow inside. A flaw detection head having an inner surface of the boring shaft and movable along the axial direction, an oil seal provided on a front side and a rear side of the ultrasonic vibrator; And oil supply means for filling a seal area surrounded by the two oil seals with oil when the oil seal is moved in the axial direction.

In the ultrasonic flaw detector according to the present invention, for example, the flaw detection head is inserted into the boring shaft so that the seal area becomes a closed space, and then oil is supplied by oil supply means to fill the seal area with oil. Thereafter, ultrasonic inspection of the boring axis is performed. In other words, this ultrasonic flaw detector does not float the flaw detection head in oil as in the prior art, but fills only the seal area formed around the ultrasonic transducer of the flaw detection head with oil. In other words, oil is used only to propagate the ultrasonic waves of the ultrasonic transducer to the inside of the boring shaft. Therefore, the amount of oil used can be significantly reduced as compared with the conventional case.

According to the ultrasonic flaw detector of the present invention, the amount of oil used is significantly smaller than that of the conventional one and the amount of oil remaining inside the boring shaft is small (for example, several tenths of the conventional one). ), Even if oil remaining inside the boring shaft is not collected, there is almost no risk of impairing the original performance of the lubricant. Therefore, it is not necessary to separately perform an oil recovery operation after the end of the flaw detection inspection, and the operation efficiency is improved.

Incidentally, in the ultrasonic flaw detector according to the present invention,
Since the outer peripheral edge of the oil seal is in contact with the inner wall of the boring shaft, when the flaw detection head is moved along the axial direction, a feed resistance is generated at this contact location. Therefore, a large thrust is required to move the flaw detection head along the axial direction. Therefore, in order to generate such a large thrust, the ultrasonic flaw detector of the present invention sends the flaw detection head substantially horizontally while sandwiching the guide tube attached to the rear end of the flaw detection head with a pinch roller. It is preferable to have a feed mechanism for moving in the axial direction.

The ultrasonic flaw detector according to the present invention may be provided with oil suction means for sucking oil from the seal area in addition to the above oil supply means. In this case, since the oil in the seal area can be collected by the oil suction means, the oil collecting operation can be performed simultaneously with the end of the flaw detection inspection. Therefore, it is not necessary to separately perform an oil recovery operation, and the operation efficiency is improved. In addition, since a small amount of oil does not remain inside the boring shaft, it is possible to reliably avoid the possibility that oil mixes with the lubricant and impairs the original performance of the lubricant.

In the ultrasonic flaw detector of the present invention, it is conceivable to improve the sealing property of the oil seal so as to prevent oil from leaking from the seal area. There is a possibility that the head does not move smoothly along the axial direction. Therefore, while reducing the feed resistance by leaking the oil from the seal area, the oil is sucked by the oil suction means so that the leaked oil does not remain, and even if the oil leaks, the seal area is constantly filled with the oil. It is preferable to balance the supply and suction of oil. That is, in the ultrasonic flaw detector of the present invention, when the flaw detection head moves inside the boring shaft along the axial direction, the oil supply means supplies oil to the seal area, and the oil suction means moves from the seal area to the oil supply means. In addition to sucking oil, oil leaked out of the seal area is sucked together with air, and the sealing performance of both oil seals and the amount of oil supply and oil suction are controlled by oil leakage from the seal area. It is preferable that the seal area is set so as to be constantly filled with the oil while the suction is balanced. In this case, the flaw detection head can be moved smoothly, so that the operability is good and the effect that there is no need to separately perform an oil recovery operation after the flaw detection inspection is obtained can be obtained in a highly feasible manner.

At this time, it is preferable that the oil suction means sucks the oil leaking to the front side (tip side) of the seal area together with air. That is, when the flaw detection head is removed from the inside of the boring shaft, the oil leaked to the rear side (rear end side) of the sealing area is scraped out by the oil seal, and therefore, hardly remains even if it is not intentionally sucked. On the other hand, the oil that has leaked to the front side of the seal area remains as it is, and thus there is a high necessity for suction by the oil suction means. For this reason, it is preferable to employ the above-described configuration.

The ultrasonic flaw detector according to the present invention is preferably provided with an air blowing means for blowing oil remaining inside the boring shaft in the drawing direction when the flaw detection head is pulled out from the inside of the boring shaft. In this case, the oil leaked from the seal area can be reliably removed without remaining.

In the ultrasonic flaw detector according to the present invention, the ultrasonic vibrator generates ultrasonic waves while rotating with the flaw detection head so that the ultrasonic waves are generated while rotating about the central axis of the flaw detection head. It may be controlled.
At this time, if the flaw detection head is simultaneously moved in the axial direction,
Ultrasonic flaw detection can be performed spirally from the inside of the boring shaft.
In this case, since the outer periphery of the oil seal rotates while sliding inside the boring shaft, the center axis of the flaw detection head and the center axis of the boring shaft almost coincide, and flaw detection can be performed with a stable ultrasonic flaw detection waveform. Data reliability is improved. On the other hand, when ultrasonic inspection is performed while rotating the inspection head while the inspection head is floated in oil as in the related art, the center axis of the inspection head and the center axis of the boring axis are hardly coincident and eccentric. Since ultrasonic flaw detection is performed in this state, the ultrasonic flaw detection waveform becomes unstable, that is, the sensitivity becomes unstable, and it is difficult to say that data reliability is high.

In the ultrasonic flaw detector of the present invention, a plurality of ultrasonic vibrators are arranged at equal intervals around the center axis of the flaw detection head, and these plural ultrasonic vibrators sequentially generate ultrasonic waves, thereby The sound wave may be controlled to be generated while rotating around the central axis of the flaw detection head.
For example, ultrasonic waves may be sequentially emitted by controlling the phase of a transmission pulse for each ultrasonic transducer. At this time, if the flaw detection head is simultaneously moved in the axial direction, the inside of the boring shaft can be ultrasonically flawed in a spiral form from the inside. In this case, since the flaw detection head itself does not need to be rotated around the axis, a conventional rotation motor, various gears, and the like are not required, so that maintenance is easy and data reliability can be improved. In addition, the gap between the flaw detection head and the inside of the boring shaft can be reduced as compared with the case where the flaw detection head itself is rotated around the axis, and the reliability of data is also improved in this respect. Preferably, eight or more ultrasonic transducers are provided at equal intervals around the central axis.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. [First Embodiment] FIG. 1 is an explanatory diagram showing the overall configuration of an ultrasonic flaw detector according to the present embodiment, FIG. 2 is a block diagram thereof, and FIG.
FIG. 4 is a sectional view of the flaw detection head, and FIG. 4 is a sectional view taken along line AA of FIG. The ultrasonic flaw detector 10 according to the present embodiment includes a flaw detection head 1
1, an ultrasonic transducer 16, a flaw detector 25, and a computer 30.

As shown in FIG. 1, the flaw detection head 11 has a substantially cylindrical shape having a diameter slightly smaller than the diameter of the inside 2a of the boring shaft 2 having wheels 1 (only one is shown in FIG. 1) on both left and right sides. The guide tube 13 is fixed to the rear end. The guide tube 13 is fed substantially horizontally in either the forward or reverse direction while being sandwiched from above and below by a plurality of upper and lower pinch rollers 14 a constituting the feed mechanism 14. When the guide tube 13 is fed into the inside 2 a of the boring shaft 2, the flaw detection head 11 advances in the inside 2 a of the boring shaft 2 along the axial direction, and
Is removed from the inside 2 a of the boring shaft 2, the flaw detection head 11 retreats along the axial direction of the inside 2 a of the boring shaft 2. The guide tube 13 and the feed mechanism 14 are mounted on a cart 15 with casters.

As shown in FIGS. 3 and 4, the ultrasonic vibrator 16 extends over the center axis of the flaw detection head 11 over two rows in front and rear at a probe portion 17 provided slightly in the middle of the flaw detection head 11. A plurality are arranged around the circumference at equal angles. These ultrasonic transducers 16 are covered with a cover 17a made of acrylic resin. The ultrasonic transducers 16a in the front row are stuck on a conical surface and are arranged in such a manner that they are obliquely incident forward by a predetermined angle.
The ultrasonic transducers 16b in the rear row are also attached to the conical surface, and are arranged so as to be inclined obliquely rearward by a predetermined angle. Each ultrasonic vibrator 16 is a composite vibrator in which a ceramic element (element material such as lead zircon titanate) is wrapped in a polymer, so that an ultrasonic beam applied to the inner wall of the boring shaft 2 is spread. Although formed in the shape of a convex lens, the radius of curvature is determined in consideration of the sound pressure incidence efficiency (the ratio of sound returning from the vibrator to the vibrator again). An adhesive is filled between the cover 17a and the ultrasonic vibrator 16, and no air layer is interposed. In the present embodiment, the ultrasonic transducers 16a and 16b in the front row and the rear row are arranged in a total of 32 pieces each of 16 pieces, but the number is not limited to this.

A front oil seal 18 and a rear oil seal 19 that are in close contact with the inner wall of the boring shaft 2 are provided on the front and rear sides of the probe portion 17 of the flaw detection head 11. The flaw detection head 11 has two oil seals 18,
An oil supply passage 20 for supplying oil to the seal region S sandwiched between the seal region 19 and an oil discharge passage 21 for sucking and discharging oil from the seal region S are provided. A secondary discharge passage 22 for sucking and discharging air and oil from the air is provided.

Here, the oil supply passage 20 is a passage of the oil unit 35 mounted on the cart 15 with casters for supplying oil to the seal area S by pressure by an oil pump (not shown). A passage for sucking oil by a vacuum pump (not shown) in the oil unit 35 and discharging the oil from the seal area S;
The secondary discharge passage 22 is a passage through which when the oil in the seal area S leaks to the distal end side, the leaked oil is sucked together with the air by the vacuum pump and discharged. Of these, the oil discharge passage 21 and the secondary discharge passage 22 are provided with through holes 24 provided inside the flaw detection head 11.
It is a passage branched from. The oil supply passage 20
And the oil unit 35 correspond to the oil supply means of the present invention, and the oil discharge passage 21, the secondary discharge passage 22, and the oil unit 35 correspond to the oil suction means of the present invention.

Further, a residual pressure exhaust port 23 is provided on the tip end surface of the flaw detection head 11. When the inside 2a of the boring shaft 2 is opened only on the insertion side of the flaw detection head 11 and the opposite side is closed, the residual pressure exhaust port 23 is provided with an internal pressure when the flaw detection head 11 advances to the back of the inside 2a. And prevents the internal pressure from dropping when the flaw detection head 11 retreats from the inside 2a to the opening side. This residual pressure exhaust port 23 is also a passage branched from the through hole 24 described above.

Further, on the peripheral surface on the tip end side of the flaw detection head 11, there are provided air outlets 36 scattered in the circumferential direction. The air outlet 36 is also connected to the above-described through hole 24, and is configured so that compressed air is supplied from an air compressor (not shown) through the through hole 24. The air outlet 36 is connected to the boring shaft 2.
When the flaw detection head 11 is pulled out from the inside 2a of the nozzle, the air is jetted in the pulling-out direction.

The flaw detector 25 is mounted on a cart 15 with casters as shown in FIG. As shown in FIG. 2, the flaw detector 25 includes a transmission / reception circuit 26 provided for each ultrasonic transducer 16 and a transmission / reception circuit 26 which generates a transmission pulse based on a phase control signal input from the computer 30. Pulse generator 27 to send to
Amplifying and detecting the signals from the respective ultrasonic transducers 16 received through the receiver 6 and outputting the amplified signals to the computer 30
8 is provided.

The computer 30 is mounted on the cart 15 with casters as shown in FIG. As shown in FIG. 2, the computer 30 sends a transmission pulse phase control signal to the transmission pulse generator 27 of the flaw detector 25, receives a signal from the reception amplifier 28, and
Or to be displayed. A rotary encoder 14b is attached to the pinch roller 14a constituting the feed mechanism 14, and the computer 30 receives a signal from the rotary encoder 14b and calculates the axial movement distance of the flaw detection head 11.

Next, a procedure for flaw detection of the boring shaft 2 using the ultrasonic flaw detection apparatus 10 of the present embodiment will be described. First, one end of the inside 2a of the boring shaft 2 is opened, and an adapter 40 is attached to the end. This adapter 40 is used for the flaw detection head 1
The oil collecting pan 41 is provided at the bottom of the adapter 40 to facilitate the oil recovery when extracting the oil from the inside 2 a of the boring shaft 2. The oil is collected in an oil tank (not shown) of the oil unit 35 through 42.
In addition, the ultrasonic flaw detector 10 is moved to the vicinity of the end of the inside 2 a of the boring shaft 2 using the cart 15 with casters of the ultrasonic flaw detector 10.

Then, the tip of the flaw detection head 11 is inserted into the adapter 40, and the pinch roller 14a of the feed mechanism 14 is driven to feed the guide tube 13 into the inside 2a of the boring shaft 2. Then, the flaw detection head 11 reaches the inside 2a of the boring shaft 2 via the adapter 40, and advances through the inside 2a. Even when the inside 2a is opened only on the insertion side of the flaw detection head 11 and the opposite side is closed, when the flaw detection head 11 advances to the back of the inside 2a, the tip side of the flaw detection head 11 exhausts residual pressure. Since it communicates with the outside air through the port 23, the internal pressure on the tip side of the flaw detection head 11 does not rise and the flaw detection head 11 does not stop moving forward.

Now, after the flaw detection head 11 is inserted into the inside 2a of the boring shaft 2 and the sealing area S of the probe section 17 becomes a closed space, oil supply is started from the oil supply passage 20, and this oil is As the air is supplied, the air in the seal area S is discharged through the oil discharge passage 21, and the seal area S is filled with oil. Thereafter, the oil supply amount from the oil supply passage 20 and the oil suction amount from the oil discharge passage 21 are adjusted so that the seal area S is constantly filled with oil. The filling of the seal area S with oil is as follows.
This is because the ultrasonic waves emitted from the ultrasonic vibrator 16 propagate through the seal area S and reach the inner wall of the boring shaft 2.

Here, it is conceivable to enhance the sealing properties of the two oil seals 18 and 19 so that oil does not leak from the seal area S. However, if this is done, the feed resistance when moving the flaw detection head 11 becomes too large and flaw detection is performed. Head 1
1 may not move smoothly along the axial direction. Therefore, while the feed resistance is reduced by leaking oil from the seal area S, the oil is sucked through the secondary discharge passage 22 so that the leaked oil does not remain, and even if the oil leaks, the oil is continuously discharged from the seal area S. The oil supply and suction are balanced so that the oil is filled.

That is, when the flaw detection head 11 moves along the inside 2a of the boring shaft 2 in the axial direction, the oil supply passage 20
Supplies oil to the seal area S, and the oil discharge passage 21
Discharges oil from the seal area S, and discharges the oil from the secondary discharge passage 22
Sucks the oil leaked out of the seal area S together with the air. The sealing performance of the two oil seals 18 and 19 and the oil supply amount and the oil suction amount are set such that the oil supply and the suction are balanced by the leakage of the oil from the seal region S so that the seal region S is constantly filled with the oil. Is set to For example, the amount of oil suctioned from the seal area S is set to be smaller than the amount of oil supplied to the seal area S, and the excess supply oil leaks from the seal area S.

When the flaw detection head 11 moves in the axial direction along the inside 2 a of the centering shaft 2, the computer 30 sends a phase control signal of a transmission pulse to the transmission pulse generator 27 of the flaw detector 25. Then, the transmission pulse generator 2 of the flaw detector 25
7 is a transmitting / receiving circuit 26 according to the phase control signal.
, The ultrasonic transducers 16 in each row are vibrated while being sequentially shifted one by one in one direction. At this time, the ultrasonic transducers 16a in the front row emit ultrasonic waves diagonally forward, and the ultrasonic transducers 16b in the rear row emit ultrasonic waves diagonally backward.

Here, the switching frequency of the transmission pulse is fs
(KHz), the ultrasonic vibrator 16 becomes 16 kHz in the circumferential direction.
The number of rotations of the ultrasonic beam N (rp
m) is obtained from the following equation (1).

[0034]

(Equation 1) If the effective beam width W (mm) of the ultrasonic beam is experimentally obtained, the flaw detection speed V (m / min) for flaw detection of the entire inner wall of the boring shaft 2 can be obtained from the following equation (2). Therefore, the feed mechanism 14 is set so as to feed the guide tube 13 at the flaw detection speed V or lower. As a result, the flaw detection head 11 can perform ultrasonic flaw detection of the inside 2a of the boring shaft 2 in a spiral manner from the inside.

[0035]

(Equation 2) Then, the reception amplifier 28 of the flaw detector 25 amplifies and detects a signal from each ultrasonic transducer 16 received through each transmission / reception circuit 26 and outputs the signal to the computer 30. The computer 30 receives the signal received from the receiving amplifier 28 and displays the signal on the display 31. In the display, the XYZ coordinates are used, the X axis is the axial position, the Y axis is the circumferential position, and the Z axis is the output difference.

Here, the output difference is obtained as follows.
That is, ultrasonic inspection is carried out by the ultrasonic inspection apparatus 10 for a case in which the inside 2a of the boring shaft 2 has no flaws in advance, and the received signal at that time is stored as a blank in a storage device (hard disk or the like) of the computer 30. Keep it.
Then, ultrasonic flaw detection is performed on the inside 2a of the boring shaft 2 to be inspected, and the received signal at that time is compared with the blank received signal to obtain an output difference between the two signals.

As a result, the peak portion on the Z axis indicates the position where the flaw is present, so that the position may be specified by the values on the X axis and the Y axis. The computer 30
The axial position of the flaw detection head 11 is calculated based on the signal received from the rotary encoder 14b attached to the pinch roller 14a, and it is known as to which ultrasonic transducer 16 emitted the ultrasonic wave from the circumferential position. Therefore, the position of the ultrasonic transducer 16 may be recognized.

When the flaw detection head 11 reaches the other end of the boring shaft 2, the guide tube 13 is pulled in the opposite direction by the feed mechanism 14, that is, the guide tube 13 is removed from the inside 2 a of the boring shaft 2. send. Then, the flaw detection head 11 retreats inside 2 a of the boring shaft 2. Even when the inside 2a is opened only on the insertion side of the flaw detection head 11 and the opposite side is closed, even if the flaw detection head 11 is closed.
When the flaw detection head 11 retreats, the tip side of the flaw detection head 11 communicates with the outside air via the residual pressure exhaust port 23, so that the internal pressure on the tip side of the flaw detection head 11 does not drop and the flaw detection head 11 does not stop retreating. Subsequent flaw detection operations are the same as those at the time of forward movement, and will not be described.

As described in detail above, according to the ultrasonic flaw detector 10 of the present embodiment, the following effects can be obtained. Oil is filled only in the seal area S formed around the ultrasonic transducer 16 of the flaw detection head 11. That is, the oil is used only to propagate the ultrasonic wave of the ultrasonic vibrator 16 to the inner wall of the boring shaft 2. Therefore, the amount of oil used can be significantly reduced as compared with the conventional case.

Since the oil in the seal area S can be recovered by the oil discharge passage 21, the secondary discharge passage 22, and the oil unit 35, the oil recovery operation can be performed simultaneously with the end of the flaw detection inspection. Therefore, it is not necessary to separately perform an oil recovery operation, and the operation efficiency is improved. Also,
Since a small amount of oil does not remain in the inside 2a of the boring shaft 2, it is possible to reliably avoid the possibility that the oil mixes with the lubricant and impairs the original performance of the lubricant.

Since the outer peripheral edges of the oil seals 18 and 19 are in contact with the inner wall of the boring shaft 2, feed resistance is generated when the flaw detection head 11 is moved in the axial direction.
Since a large thrust is generated by sending the guide tube 13 substantially horizontally while sandwiching the guide tube 13 from above and below with the pinch roller 14a, the flaw detection head 11 can be moved smoothly in the axial direction.

While the feed resistance is reduced by leaking oil from the seal area S, the leaked oil is sucked by the secondary discharge passage 22 so that the oil does not remain. The oil supply and suction are balanced to be filled with oil. Therefore, the flaw detection head 11 can be moved smoothly, so that the operability is good and the effect that there is no need to separately perform an oil recovery operation after the completion of the flaw detection inspection is obtained in a highly feasible manner.

The flaw detection head 11 is located inside 2 a of the boring shaft 2.
By ejecting air from the air ejection port 36 when the oil is extracted from the oil, the oil remaining on the inner wall of the boring shaft 2 is blown off in the extraction direction by the air, so that the remaining oil can be more reliably removed.

The inside of the boring shaft 2 of the flaw detection head 11 is
When the oil is extracted from the seal area S, the oil leaked to the rear side of the seal area S is scraped out by the oil seals 18 and 19, and thus does not remain without being intentionally sucked. Therefore, the remaining oil is almost completely removed by sucking the oil through the secondary discharge passage 22.

In this embodiment, as compared to the conventional case where the flaw detection head 101 is floated on oil, the flaw detection head 1
A gap between the inner shaft 1 and the inner wall of the boring shaft 2 can be reduced, and in this respect, data reliability is improved. When the inside 2a of the boring shaft 2 is subjected to ultrasonic flaw detection in a spiral form from the inside, it is not necessary to rotate the flaw detection head 11 around the axis, so that the conventional rotary motor 104a, various gears 104c, and the like are not required. , Maintenance is easy and data reliability can be improved.

The ultrasonic vibrator 16 has a front row of ultrasonic vibrators 16a arranged obliquely toward the front and a rear row arranged obliquely rearward. The ultrasonic vibrator 16b is used to determine the presence or absence of a flaw based on the reflected wave of the ultrasonic wave emitted by the ultrasonic vibrator 16a, depending on the direction of the flaw generated on the boring shaft 2. Even if there is a possibility that the user may mistakenly recognize that there is no flaw, it can be clearly recognized that there is a flaw based on the reflected wave of the ultrasonic wave emitted from the ultrasonic transducer 16b.
For this reason, the accuracy of flaw detection can be further increased.

[Second Embodiment] FIG. 5 is a sectional view of a flaw detection head according to this embodiment. In the present embodiment, the flaw detection head 101 configured to be rotated by the rotation motor 104a described in the section of [Prior Art] will be described with respect to the front side and the rear side of the ultrasonic transducer 103 in the same manner as the first embodiment. Are provided with oil seals 18 and 19 to form a seal area S. Further, the same oil supply passage 2 as in the first embodiment is used.
0, an oil discharge passage 21, a secondary discharge passage 22, a residual pressure exhaust port 23, and an air outlet 36, and the same feed mechanism 14 as in the first embodiment is employed. Since these functions have been described in the first embodiment, the description thereof is omitted here.

In the present embodiment, the ultrasonic transducer 103 generates ultrasonic waves while rotating with the flaw detection head 101, and is controlled so that the ultrasonic waves are generated while rotating about the central axis of the flaw detection head 101. You. Here, since the outer peripheral edges of the oil seals 18 and 19 rotate while sliding on the inner wall of the boring shaft 2, the central axis of the flaw detection head 101 and the central axis of the boring shaft 2 substantially coincide with each other, and a stable ultrasonic wave is obtained. Flaw detection can be performed with a flaw detection waveform, and data reliability is improved. In the present embodiment, the effects (1) to (1) of the first embodiment can also be obtained.

The embodiments of the present invention are not limited to the above-mentioned embodiments at all, and it goes without saying that various forms can be adopted as long as they fall within the technical scope of the present invention. For example, in the above embodiment, the oil discharge passage 21
And without providing the secondary discharge passage 22, the two oil seals 18,
The sealability of 19 may be enhanced so that oil does not leak from the seal area S when the flaw detection head 11 moves in the axial direction. In this case, the feed resistance when moving the flaw detection head 11 is increased, but the amount of oil used is significantly smaller than that of the ultrasonic flaw detection apparatus described in [Prior Art]. Therefore, even if the oil remaining in the inside 2a of the boring shaft 2 is not collected, there is almost no risk that the small amount of oil will impair the original performance of the lubricant. Therefore, it is not necessary to separately perform an oil recovery operation after the end of the flaw detection inspection, and the operation efficiency is improved. However, the oil discharge passage 21 may be provided to collect the oil at the same time as the end of the flaw detection inspection.

The oil supply passage 20 is located in the seal area S
However, the openings may be provided so as to be scattered along the circumferential direction, and the oil may be discharged from each of the openings. Similarly, the oil discharge passage 21 may be provided so that the openings are scattered along the circumferential direction, and the oil may be sucked from each of the openings. Alternatively, these openings may be circumferential grooves.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram illustrating an overall configuration of an ultrasonic flaw detector according to a first embodiment.

FIG. 2 is a block diagram of the ultrasonic flaw detector according to the first embodiment.

FIG. 3 is a cross-sectional view of the flaw detection head according to the first embodiment.

FIG. 4 is a sectional view taken along line AA of FIG. 3;

FIG. 5 is a sectional view of a flaw detection head according to a second embodiment.

FIG. 6 is an explanatory diagram of a conventional example.

[Explanation of symbols]

2 ... boring shaft, 2a ... inside boring shaft, 10
..Ultrasonic flaw detector, 11 ... flaw detection head, 13 ...
・ Guide tube, 14 ... feed mechanism, 14a ...
Pinch roller, 14b ... Rotary encoder, 15
... Dolly with casters, 16, 16a, 16b ...
Ultrasonic vibrator, 17: probe, 18: front oil seal, 19: rear oil seal, 20: oil supply passage, 21: oil discharge passage, 22 ...
Secondary discharge passage, 23 ... residual pressure exhaust port, 24 ...
Through hole, 25: flaw detector, 26: transmitting / receiving circuit, 27
... Transmission pulse generator, 28 ... Reception amplifier, 30
... Computer, 31 ... Display, 3
5 ... oil unit, 36 ... air outlet,
40: Adapter, 41: Oil recovery pan, 42
... Recovery tube.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shigeaki Matsumoto 1-8 Fuso-cho, Amagasaki City, Hyogo Prefecture Inside Sumitomo Metal Technology Co., Ltd. (72) Inventor Yasukazu Fujii 1-8 Fuso-cho Amagasaki City, Hyogo Sumitomo Inside Metal Technology Co., Ltd. (72) Inventor Yasuhiro Ohara 1-8 Fuso-cho, Amagasaki-shi, Hyogo Sumitomo Metal Technology Co., Ltd. F-term (reference) 2G047 AA07 AB01 AC08 DB02 DB05 DB18 EA10 GA19 GB04 GE04 GE05 GJ08 GJ13 GJ14

Claims (8)

[Claims] 1. An ultrasonic flaw detector for flaw detection of a hollow boring shaft having a hollow inside, comprising an ultrasonic vibrator for flaw detection, the flaw detecting device being capable of moving inside the boring shaft along an axial direction. A head, an oil seal provided on a front side and a rear side of the ultrasonic vibrator, and a seal surrounded by the oil seals when the flaw detection head moves inside the boring shaft along the axial direction. An ultrasonic flaw detector comprising an oil supply means for filling an area with oil. 2. The ultrasonic flaw detector according to claim 1, wherein a guide tube attached to a rear end of the flaw detection head is fed substantially horizontally while being pinched by a pinch roller, thereby moving the flaw detection head in the axial direction. An ultrasonic flaw detector comprising a feed mechanism for moving along an axis. 3. The ultrasonic flaw detector according to claim 1, further comprising oil suction means for sucking oil from the seal area. 4. The ultrasonic flaw detector according to claim 3, wherein said oil supply means includes an oil supply means for supplying oil to said seal area when said flaw detection head moves inside said boring shaft along an axial direction. When the flaw detection head moves inside the boring shaft along the axial direction, the oil suction means sucks oil from the seal region and air leaks oil leaked out of the seal region. The sealability of the two oil seals, the oil supply amount of the oil supply means, and the oil suction amount of the oil suction means are balanced between oil supply and suction due to oil leakage from the seal area. An ultrasonic flaw detector wherein the seal area is set to be constantly filled with oil. 5. The ultrasonic flaw detector according to claim 3, wherein the oil suction means suctions oil leaked to a front side of the seal region together with air. 6. The ultrasonic flaw detector according to claim 1, wherein when the flaw detection head is pulled out of the boring shaft, oil remaining in the boring shaft is drawn out by air. An ultrasonic flaw detector comprising an air blowing means for blowing air toward the surface. 7. The ultrasonic flaw detector according to claim 1, wherein the ultrasonic vibrator generates an ultrasonic wave while rotating axially together with the flaw detection head, thereby generating the ultrasonic wave. An ultrasonic flaw detector which is controlled so as to be generated while rotating around a central axis of the flaw detection head. 8. The ultrasonic flaw detector according to claim 1, wherein a plurality of the ultrasonic vibrators are arranged at equal intervals around a central axis of the flaw detection head. An ultrasonic flaw detector, wherein the ultrasonic vibrator generates ultrasonic waves sequentially, so that the ultrasonic waves are controlled to be generated while rotating around the central axis of the flaw detection head.