JPH06242087A - Ultrasonic flaw detecting system - Google Patents

Abstract

PURPOSE:To allow high speed, high resolution ultrasonic flaw detecting operation for a specimen having free curve surface through a simple mechanism. CONSTITUTION:The ultrasonic flaw detecting system wherein an untrasonic probe 1 movable in Z-direction and communicating ultrasonic wave with a specimen scans, through a scanning means 4, on the specimen in the direction perpendicular to Z-direction to obtain ultrasonic signals from the specimen comprises means 19-21 for supporting the scanning means 4 movably in Z- direction with respect to the specimen, a dummy specimen 33 having surface profile simulating that of the specimen, and a copying means 22 moving up and down in Z-direction while copying the surface profile of the dummy specimen 33 thus moving the scanning means 4 in Z-direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is to transmit and receive ultrasonic waves between a subject and an ultrasonic probe while scanning the ultrasonic probe to obtain ultrasonic waves of the subject at a specific depth. The present invention relates to an ultrasonic flaw detector for obtaining images and the like.

[0002]

2. Description of the Related Art FIG. 4 is a diagram showing a conventional example of this type of ultrasonic flaw detector, and is a block diagram showing the circuit configuration thereof. In FIG. 4, reference numeral 1 denotes an ultrasonic probe that transmits and receives ultrasonic waves to and from the subject 3, and the ultrasonic probe 1 is attached to the three-dimensional scanning device 4. Scanning device 4
Includes a surface plate 10, a frame 11 fixed on the surface plate 10, and a Y-axis scanner 12, an X-axis scanner 13 and a Z-axis scanner 14 attached to the frame 11. The Y-axis scanner 12 has a drive motor 17a.
The driving force of the X-axis scanner 1 enables movement in the Y direction (direction orthogonal to the paper surface of FIG. 4) with respect to the frame 11.
3 is the Y-axis scanner 1 by the driving force of the drive motor 17b.
2 is movable in the X direction (left and right direction in FIG. 4), and the Z axis scanner 14 is further moved in the Z direction (up and down direction in FIG. 4) with respect to the X axis scanner 13 by the driving force of the drive motor 17c. It is supposed to be movable. A jig 18 is fixed to the Z-axis scanner 14, and the ultrasonic probe 1 is attached to the tip of the jig 18. 16 is water 1
5 is a water tank filled with the scanning device 4 in the depth direction.
Are arranged on the surface plate 10 so as to coincide with the Z direction. The subject 3 is placed in the water tank 16 in a submerged state.

Reference numeral 2 denotes an ultrasonic wave transmitting / receiving section, which includes a pulsar receiver 2a and a peak detector 2b. The pulsar receiver 2a applies a pulsed voltage to the probe 1 to irradiate ultrasonic waves from the probe 1 toward the subject 3, and at the same time, is received by the probe 1 and converted into an electric signal. The reflected ultrasonic signal from the subject 3 is amplified. Peak detector 2b
Outputs a DC voltage proportional to the peak value of the signal within an arbitrary propagation time from the received signal from the pulser receiver 2a. The computer 5 controls the entire ultrasonic flaw detector, and instruction data and the like from the operator is input via the keyboard 8. The computer 5 drives and controls the drive motors 17a, 17b, and 17c of the scanning device 4 via the controller 6, scans the ultrasonic probe 1, and scans the measurement points of the subject 3 (usually XY plane, XZ). The reflected ultrasonic wave from the plane or the YZ plane) is received, and the monitor 7 displays the imaged data captured at each measurement point.

FIG. 5 is a diagram showing an example of a conventional ultrasonic probe applied to FIG. As shown in FIG. 5, the ultrasonic probe 1 includes a piezoelectric element 30 formed in a thin plate or thin film shape, and an acoustic lens having a concave surface 31a for converging the ultrasonic waves generated by the piezoelectric element 30 at the lower end. 31 and 31 are provided. The ultrasonic beam UB emitted from the lower end of the acoustic lens 31 of the ultrasonic probe 1 is converged at the position F of the focal length f peculiar to each probe determined by the curvature of the concave surface 31a.
5, the ultrasonic beam UB is refracted at the interface when the ultrasonic beam UB enters the subject 3 because the acoustic impedances of the subject 3 and the water 15 are different, and is usually shorter than the focal length f. It converges at the focal position F ′ of the distance (shown by the solid line in FIG. 5).

[0005]

However, in the above-mentioned conventional ultrasonic flaw detector, when the distance (water distance) between the surface of the subject 3 and the probe 1 changes, this is accompanied. There is also a problem that the focal position of the ultrasonic beam also fluctuates, the ultrasonic image becomes unclear, and the resolution deteriorates. That is, in recent years, ultrasonic flaw detectors are being applied to the measurement of the material properties of composite materials having a three-dimensional curved surface used in aircraft and the like, and when measuring a material having such a three-dimensional curved surface, an ultrasonic probe is used. Even when 1 is scanned along the XY plane, the distance between the surface of the subject 3 and the ultrasonic probe 1 is not necessarily constant because the surface position of the subject 3 is different at each measurement point. In such a case, when the ultrasonic beam UB enters the subject 3 as described above, the ultrasonic beam UB is converged to the position F ′ by refraction based on the acoustic impedance difference between the subject 3 and the water 15. When the distance between the surface of the subject 3 and the probe 1 changes, the subject 3
The incident angle on the lens fluctuates accordingly, and the focal position F ′ also fluctuates. Then, if the focal position changes, the ultrasonic image may become unclear and the resolution may deteriorate. Note that, in FIG. 5, a case where the surface of the subject 3 and the focus position F coincide with each other is shown by a chain double-dashed line.

Therefore, in the conventional ultrasonic flaw detector, by using the probe 1 having a concave surface 31a having a small curvature and a long focal length, the incident angle to the object 3 is made small and the object 3 is made small. Even if the distance between the surface of No. 3 and the probe 1 changes, the focal position does not change greatly. However, a probe with a long focal length has inherently low resolution, and as a result is not an essential solution.

As a technique for preventing blurring of an ultrasonic image while using a probe having a short focal length and a high resolution, the distance between the surface of the subject 3 and the probe 1 is always maintained. A method of scanning the ultrasonic probe 1 while keeping it constant can be mentioned. As a technique for measuring the distance between the surface of the subject 3 and the probe 1 and keeping the distance constant, for example, the actual open sho 59
There are technologies disclosed in Japanese Patent Publication No. 166164, Japanese Utility Model Publication No. 59-194063, and the like. However, in these conventional techniques, the distance between the subject and the probe is measured by ultrasonic waves, and the movement of the subject or the probe is controlled so that this distance becomes constant. , In addition to the scanning mechanism of the ultrasonic probe, the movement control mechanism of the subject or the probe is added,
There is a problem that the control procedure and mechanism are complicated and high-speed scanning of the subject is difficult.

An object of the present invention is to provide an ultrasonic flaw detector which is capable of performing high-resolution and high-speed ultrasonic flaw detection on a subject having a free-form surface while having a simple mechanism. .

[0009]

The invention of claim 1 will be described with reference to FIG. 1 and FIG. 3 showing an embodiment.
The ultrasonic probe 1 that is movable in the direction and transmits and receives ultrasonic waves to and from the subject 3 is scanned by the scanning means 4 in a direction orthogonal to the Z direction, It is applied to ultrasonic flaw detectors that obtain ultrasonic signals. And
The above-mentioned purpose is to support the scanning means 4 with respect to the subject 3 so as to be movable in the Z direction.
A dummy object 33 having a surface shape imitating the surface shape of the object 3; and a vertical movement in the Z direction following the surface shape of the dummy object 33 to move the scanning means 4 in the Z direction. This is achieved by providing a copying unit 22 for causing the copying. Further, the invention of claim 2 is such that a dummy object 33 having a surface shape imitating the surface shape of the object 3 and a scanning signal output means 24 for outputting a scanning signal according to the surface shape of the dummy object 33. And the copy signal output means 2
Moving means for moving the ultrasonic probe 1 so that the distance between the ultrasonic probe 1 and the surface of the subject 3 becomes approximately a predetermined value based on the scanning signal output from the ultrasonic probe 1. 14
By providing and, the above-mentioned object is achieved.

[0010]

[Action]

-Claim 1- The copying unit 22 moves up and down in the Z direction following the surface shape of the dummy subject 33, and the vertical movement moves the scanning unit 4 in the Z direction. As the scanning means 4 moves in the Z direction, the ultrasonic probe 1 also moves in the Z direction, whereby the ultrasonic probe 1 follows the dummy object 33, that is, the surface shape of the object 3. Moves up and down in the Z direction. -Claim 2- The moving means 14 determines the distance between the ultrasonic probe 1 and the surface of the subject 3 based on the scanning signal output by the scanning signal output means 24 according to the surface shape of the dummy subject 33. The ultrasonic probe 1 is moved so that is approximately a predetermined value.

Incidentally, in the section of means and action for solving the above problems for explaining the constitution of the present invention, the drawings of the embodiments are used for making the present invention easy to understand. It is not limited to.

[0012]

【Example】

First Embodiment FIG. 1 is a diagram showing a first embodiment of the ultrasonic flaw detector according to the present invention, and is a diagram showing the overall configuration thereof. In the following description, constituent elements having the same functions and actions as those of the conventional example are designated by the same reference numerals, and the description thereof will be simplified.

Also in this embodiment, the ultrasonic probe 1 has three
The scanning device 4 is attached to the tip of the jig 18 of the dimensional scanning device 4, and the scanning device 4 is moved between the pair of frames 11 provided on the surface plate 10 and the frames 11 in the Y direction in the figure. A Y-axis scanner 12 that is erected so that the X-axis is mounted on the Y-axis scanner 12 so as to be movable in the X direction in the figure.
Provided on the X-axis scanner 13 and the X-axis scanner 13,
A Z-axis scanner 14 that supports the jig 18 so as to be movable in the Z direction in the drawing is provided. However, in this embodiment, the frame 11 is supported on the surface plate 10 via the spring 19 and the damper 20, and a pair of guide mechanisms 21 (in FIG. Only one side is shown), so that movement is allowed only in the Z direction in the figure. As a result, each frame 11 is moved to Z relative to the surface plate 10.
It moves only in the direction, and the spring 19 and the damper 20 dampen fine movements and vibrations. The subject 3 having an arbitrary three-dimensional free-form surface is placed in a water tank 16 filled with water 15 as in the conventional example.

A table 23 having an upper surface parallel to the bottom surface of the water tank 16 is provided on the surface plate 10.
A dummy subject 33 having the same surface shape as that of the subject 3 placed in the water tank 16 is placed on the surface 3. The size of the upper surface of the table 23 is at least wider than the maximum scanning range of the scanning device 4 on the XY plane.

On the other hand, the X-axis scanner 13 is provided with a probe 22 whose tip 22a extends toward the table 23. The probe 22 includes an arm portion 22b that extends substantially horizontally from the X-axis scanner 13 in the X direction, and a detection portion 22c that descends in the Z direction from the tip of the arm portion 22b. As shown in FIG. 2, the detection unit 22c includes an inner tube 40 and an outer tube 4 which are connected to each other.
The outer pipe 41 is configured to be expandable and contractable with respect to the inner rod 40 by a predetermined range by externally fitting the inner pipe 1. Outer tube 41
A spring 42 is arranged inside. Inner rod 40
While a slit 40a is formed along the longitudinal direction thereof, a through hole 41a is formed in the outer tube 41 at a position facing the slit 40a, and a bolt 43 is penetrated through the slit 40a and the through hole 41a. The expansion and contraction position of the outer tube 41 with respect to the inner rod 40 can be fixed by tightening and fixing with the nut 44. The tip 22a of the probe 22 has a dummy object 33, as will be described later.
In order to slide on the surface, it is preferable to provide rolling means such as rollers or friction reducing means such as Teflon (registered trademark) processing.

The bottom surface of the water tank 16 and the top surface of the table 23 are formed with grids of the same pitch, and
Means for associating the XY coordinate values of the probe 1 with the position of the tip 22a of the probe 22, for example, a scale of the XY coordinate values is formed on the upper surface of the table 23.

The constructions of the ultrasonic wave transmitting / receiving section 2, the computer 5, the controller 6, the monitor 7, the keyboard 8 and the drive motors 17a to 17c are substantially the same as those of the conventional example, and the description thereof will be omitted.

Next, referring to FIG. 1, the flaw detection operation of the subject by the ultrasonic flaw detection apparatus of this embodiment will be described. Note that the flaw detection of the subject described below is performed by collecting data from a plurality of measurement points on the XY plane.

First, as shown in FIG. 1, the subject 3 is placed on a predetermined position on the bottom surface of the water tank 16, and the dummy subject 33 is placed on a corresponding position on the table 23. Further, the detection portion 22c of the probe 22, that is, the outer tube 41 is expanded and contracted so that the tip portion 22a is attached to the dummy subject 33.
The surface of the detection part 22c is fixed in this state by a bolt 43 and a nut 44 (not shown in FIG. 1). The expansion / contraction position of the detection unit 22c is lower than the most recessed position of the dummy subject 33 at the balance position where the spring 19 bends due to the weight of the frame 11 and the respective axis scanners 12 to 14. Determined to be located. As a result, as will be described later, the detection unit 22 of the probe 22 is located at the most recessed position of the dummy subject 33.
c can contact. After this, the drive motors 17a, 17
b to drive the X-axis scanner 13 and the Y-axis scanner 12
Then, the probe 1 is moved to the inspection start position.

Next, the drive motor 17c is driven to lower the probe 1 in the Z direction by the Z-axis scanner 14,
When the operator observes and confirms the ultrasonic signal displayed on the monitor 7 whether or not the focus position of the probe 1 is set at the position of the target surface depth, the surface of the subject 3 is detected. The distance (water distance) from the probe 1 is adjusted and set. After that, the peak detector 2 is provided so that the peak value of the ultrasonic signal near the propagation time (delay time) corresponding to the focus position can be detected.
Set b.

Further, the operator sends an XY plane scanning command to the computer 5 via the keyboard 8, and the computer 5 causes the drive motors 17a, 17 to be sent via the controller 6.
b, and drives the X-axis scanner 13 and the Y-axis scanner 12
The probe 1 is moved along the XY plane via.

As the probe 1 moves, the Y-axis scanner 12
The probe 22 protruding from the needle also moves, and the tip 22 of the probe 22 is moved.
It moves up and down in the Z direction following the surface position of the dummy subject 33 with which a is in contact. Therefore, the X-axis scanner 13,
The Y-axis scanner 12 and the Z-axis scanner 14 include a probe 22.
The probe 1 which moves up and down in the Z direction with a displacement equal to the displacement of the vertical movement of the probe 1 and is fixed to the jig 18 of the Z-axis scanner 14.
Also moves up and down with this. Since the dummy test object 33 is arranged at a position on the table 23 corresponding to the position of the test object 3 on the bottom surface of the water tank 16, the vertical movement of the probe 1 in the Z direction is the test object in the water tank 16. It follows the surface position of No. 3. Therefore, the probe 1 moves along the three-dimensional free-form surface of the subject 3, the distance between the probe 1 and the surface of the subject 3 is kept constant, and the focus position of the probe 1 becomes Subject 3
It is maintained at a certain depth from the surface of the.

In particular, in the present embodiment, the tip portion 22a of the probe 22 is located at a balance position where the spring 19 is bent by the own weight of the frame 11 and the respective axis scanners 12 to 14 rather than the most recessed position of the dummy subject 33. Since the expansion / contraction position of the detection portion 22c is determined so as to be located below, the spring 19 is extended in a state where the tip end portion 22a of the probe 22 is in contact with the surface of the dummy subject 33, and the repulsive force causes A downward force acts on the probe 22. And
Since this force acts on the probe 22 through the scanning operation, the tip portion 22a of the probe 22 is always pressed against the surface of the dummy subject 33, and the surface position of the dummy subject 33 changes greatly in the vertical direction. However, it is possible to follow this.

Therefore, according to the present embodiment, the probe 22
Directly utilizes the force of moving up and down in accordance with the surface position of the dummy subject 33 to vertically move each of the axis scanners 12 to 14, and the vertical movement of each of the axis scanners 12 to 14 causes the probe 1 and the subject 3 to move. Since the distance to the surface is kept constant, there is no need to provide a position control mechanism for the probe 1 separately from the scanning mechanism as in the above-mentioned conventional technique, or the Z-axis scanner 1
Since it is not necessary to use 4 to control the position of the probe 1, the control procedure and mechanism are simple, the conventional three-dimensional scanning device 4 can be used, and the subject 3 can be scanned at high speed. In addition, since the distance between the probe 1 and the surface of the subject 3 can be kept constant at all times, it is possible to apply a probe having a short focal length and high resolution. High-resolution and high-speed ultrasonic flaw detection operation can be performed on a subject having a curved surface.

-Second Embodiment- FIG. 3 is a view showing a second embodiment of the ultrasonic flaw detector according to the present invention, and is a view showing the overall structure thereof. In the following description, differences between the first embodiment and the second embodiment will be mainly described, and description of common parts will be simplified.

In the present embodiment, instead of omitting the bolts 43 and nuts 44 for fixing the expansion / contraction position of the detection portion 22c of the probe 22, the displacement sensor 24 for detecting the expansion / contraction of the detection portion 22c in the Z direction is used. It is provided. Displacement sensor 2
Reference numeral 4 denotes a well-known configuration, for example, a linear encoder, a rotary encoder, etc.
The configuration is not limited as long as the displacement in the Z direction of 1, that is, the amount of expansion and contraction can be measured. The detection signal of the displacement sensor 24 is input to the computer 5 via the converter 25.
Further, in this embodiment, the spring 19 and the damper 20 are omitted, and the frame 11 is fixedly installed on the surface plate 10.

Next, with reference to FIG. 3, the flaw detection operation of the subject by the ultrasonic flaw detector of the present embodiment will be described. First, similarly to the above-described first embodiment, after arranging the subject 3 and the dummy subject 33 at the corresponding positions, respectively, the drive motor 17
By driving a and 17b, the probe 1 is moved to the inspection start position by the X-axis scanner 13 and the Y-axis scanner 12. In this embodiment, since the fixing mechanism of the detection unit 22c, that is, the bolt 43 and the nut 44 are omitted, the outer tube 41 of the detection unit 22c is freely expanded and contracted, and the probe 1 is moved to the inspection start position. Tip 22 of the probe 22
a is in contact with the surface of the dummy subject 33.

Next, the probe 1 is moved by the Z-axis scanner 14.
While lowering in the Z direction, the operator confirms the focus position of the probe 1 to adjust and set the distance (water distance) between the surface of the subject 3 and the probe 1. After that, the peak detector 2b is set so that the peak value of the ultrasonic signal near the propagation time (delay time) corresponding to the focus position can be detected.

Further, the operator sends an XY plane scanning command to the computer 5 through the keyboard 8, and the computer 5 causes the drive motors 17a, 17 through the controller 6.
b, and drives the X-axis scanner 13 and the Y-axis scanner 12
The probe 1 is moved along the XY plane via. As the probe 1 moves, the probe 22 protruding from the Y-axis scanner 12 also moves, and the detection unit 22c follows the surface position of the dummy subject 33 with which the tip 22a of the probe 22 is in contact. Is Z
Stretch in the direction. The expansion / contraction of the detection unit 22c is determined by the displacement sensor 24.
And the expansion amount is input to the computer 5 via the converter 25. The computer 5 uses the displacement sensor 2
Based on the detection signal of No. 4, a command is issued to the drive motor 17c so that the distance between the probe 1 and the surface of the subject 3 becomes constant, and the probe 1 is moved through the Z-axis scanner 14 in the Z direction. Move to. As an example, the expansion / contraction amount of the detection unit 22c is Δ (Δ
Is either positive or negative), the probe 1
A command may be issued to the drive motor 17c so that the amount of movement in the Z direction also becomes Δ. By moving the probe 1 in the Z direction,
The probe 1 moves along the three-dimensional free-form surface of the subject 3,
The distance between the probe 1 and the surface of the subject 3 is kept constant, and the focus position of the probe 1 is maintained at a position of a certain depth from the surface of the subject 3.

Therefore, according to the present embodiment, the displacement sensor 24 detects the expansion / contraction amount of the detecting portion 22c of the probe 22 which expands / contracts in accordance with the surface position of the dummy object 33, and the probe 1 and the object 3 are detected. Z so that the distance from the surface of
Since the axis scanner 14 is driven and controlled, it is not necessary to provide a position control mechanism for the probe separately from the scanning mechanism as in the above-described conventional technique, and the control procedure and mechanism are simple and the conventional three-dimensional scanning device 4 is used. It can be diverted and the subject 3
It becomes possible to perform high speed scanning. In addition, the probe 1 and the subject 3
Since the distance to the surface of the probe can be kept constant at all times, it is possible to apply a probe with a short focal length and high resolution, which allows a simple mechanism with high resolution for an object having a free-form surface. In addition, high-speed ultrasonic flaw detection operation can be performed.

In the correspondence between the embodiment described above and the scope of the claims, the scanning device 4 includes the scanning means, the spring 19,
The damper 20 and the guide mechanism 21 serve as support means for the probe 2.
Reference numeral 2 is a copying unit, displacement sensor 24 is a copying signal output unit, and Z-axis scanner 14 is a moving unit.

The details of the ultrasonic flaw detector of the present invention are not limited to those of the above-described embodiments, and various modifications are possible. As an example, the shape and configuration of the probe 22 are not limited to those of the respective embodiments, and may be any one that moves up and down in the Z direction in accordance with the surface shape of the dummy subject 33. Further, in the second embodiment, it is also possible to measure the surface shape of the dummy subject 33 in real time by a non-contact type sensor or the like and use it for drive control of the Z-axis scanner 14.

[0033]

As described in detail above, according to the present invention, the scanning means or the probe is moved in the Z direction by following the surface shape of the dummy object having a surface shape imitating the surface shape of the object. Since the distance between the probe and the surface of the subject is maintained at a substantially predetermined value by moving the probe to the above position, it is necessary to provide the probe position control means separately from the scanning means as in the above-mentioned conventional technique. Instead, the control procedure and mechanism are simple, the conventional scanning device can be used, and high-speed scanning of the subject can be performed. In addition, since the distance between the probe and the surface of the subject can be maintained at a substantially predetermined value at all times, a probe with a short focal length and high resolution can be applied. High-resolution and high-speed ultrasonic flaw detection operation can be performed on a subject having a curved surface.

[Brief description of drawings]

FIG. 1 is a diagram showing an overall configuration of an ultrasonic flaw detector according to a first embodiment of the present invention.

FIG. 2 is a partial cross-sectional front view showing details of a detection unit of a probe.

FIG. 3 is a diagram showing an overall configuration of an ultrasonic flaw detector according to a second embodiment of the present invention.

FIG. 4 is a block diagram showing a circuit configuration of an example of a conventional ultrasonic flaw detector.

FIG. 5 is a cross-sectional view showing a schematic configuration of an ultrasonic probe.

[Explanation of symbols]

 1 probe 3 subject 4 scanning device 10 surface plate 11 frame 12 Y-axis scanner 13 X-axis scanner 14 Z-axis scanner 15 water 16 water tank 17a, 17b, 17c drive motor 19 spring 20 damper 21 guide mechanism 22 probe 22a tip Part 22b Arm part 22c Detection part 23 Table 24 Displacement sensor 33 Dummy subject

Claims (2)

[Claims] 1. An ultrasonic probe, which is movably provided in the Z direction and transmits and receives ultrasonic waves to and from the subject, is scanned by a scanning means in a direction orthogonal to the Z direction, and the subject is scanned. In an ultrasonic flaw detection apparatus for obtaining an ultrasonic signal from a device, supporting means for supporting the scanning means so as to be movable in the Z direction with respect to the object, and a dummy object having a surface shape imitating the surface shape of the object. An ultrasonic flaw detector, comprising: a sample; and a copying unit that moves up and down in the Z direction to move the scanning unit in the Z direction, following the surface shape of the dummy object. 2. An ultrasonic probe, which is provided so as to be movable in the Z direction and transmits and receives ultrasonic waves to and from the subject, is scanned by a scanning means in a direction orthogonal to the Z direction. In an ultrasonic flaw detection apparatus for obtaining an ultrasonic signal from, a dummy object having a surface shape imitating the surface shape of the object, and a scanning signal output means for outputting a scanning signal according to the surface shape of the dummy object And, based on the scanning signal output from the scanning signal output means, moves the ultrasonic probe so that the distance between the ultrasonic probe and the surface of the subject becomes a substantially predetermined value. An ultrasonic flaw detector, comprising: