JPS593256A - Array type probe - Google Patents

Abstract

PURPOSE:To make it possible to closely bring a probe surface into contact with an object to be inspected easily regardless of the configuration thereof, by a method wherein plural ultrasonic vibrator sets are roughly arranged and the spaces between each ultrasonic vibrator sets are respectively connected by connecting materials in a bendable and deformable manner. CONSTITUTION:An array type probe 1 is constituted from N numbers of ultrasonic vibrator sets 2(1)-2(N) arranged in parallel relation to each other and the aforementioned each sets are respectively constituted from M numbers of ultrasonic vibrators 3(1)-3(M). In adition, flexible connecting rods 7 are attached between each ultrasonic vibrator sets 2(1)-2(N). By this connecting rods 7, the distances between each ultrasonic vibrator elements 2(1)-2(N) are kept constant and each ultrasonic vibrator sets are constituted so as to be subjected to free and mutual positional displacement in the arranged direction thereof. By this method, a probe surface can be brought into contact with an object to be inspected closely and easily regardless of the configuration thereof.

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention uses electronic scanning ultrasonic flaw detection to inspect internal defects and discontinuous shapes of metallic materials, non-metallic materials, and structures made of these materials. This paper relates to improvements to array-type probes used for flaw detection by method.

[Technical background of the invention and its problems]

The electronic scanning ultrasonic flaw detection method uses a play-type probe in which multiple ultrasonic waves W are arranged, and by electronically controlling the timing of ultrasonic transmission and reception by each transducer, the ultrasonic beam is This allows it to be deflected in any direction and focused.

For this reason, generally, according to the electronic scanning ultrasonic flaw detection method, it is possible to transmit and receive ultrasonic beams in accordance with the shape of the object to be inspected, and the accuracy of ultrasonic flaw detection is also greatly improved.

However, array type probes generally have a structure in which multiple ultrasonic transducers are closely arranged in one direction, so the probe surface side that transmits and receives ultrasonic waves is flat, so When the probe contact surface of the array type probe has a curved shape, it is difficult to uniformly bring the entire probe surface of the array type probe into contact with the object to be inspected. In particular, when detecting thick plate materials using the electronic scanning method, an ultrasonic beam is incident obliquely on the thick plate part, and the ultrasonic waves are focused so that the desired flaw detection area is projected onto the stone in the direction of deflection of the ultrasonic beam. It must be within the near field limit distance determined by the array type probe aperture size, the frequency of the ultrasound used, and the sound speed of the object to be tested, and the directivity at the focal point of the ultrasound beam. In order to improve flaw detection, the size of the array type probe must be increased, which is expensive, and furthermore, it becomes difficult for the array type probe to uniformly contact the curved surface of the object to be inspected, resulting in poor flaw detection accuracy. becomes worse.

For this reason, conventionally, a shoe made of acrylic resin, metal, or non-metallic material is attached to the ultrasonic transmitting/receiving surface of a play-type probe, and a shoe made of acrylic resin, metal, or non-metallic material is attached to the ultrasonic transmitting/receiving surface of the play-type probe, and the shoe is adjusted to fit the curved shape of the object to be inspected. The aim is to improve the acoustic coupling with the object to be inspected, and to improve the efficiency of ultrasonic transmission and reception with the object to be inspected via liquids such as water or oil.

However, according to these methods, it is necessary to prepare a shoe for each shape of the object to be inspected, and it is difficult to follow changes in the shape of the object to be inspected and maintain stable acoustic coupling at all times. It is.

Furthermore, even with the so-called water immersion flaw detection method, which uses liquids such as water or oil, complex jigs are required to ensure a safe liquid at all times, and in particular, array type probes must be moved over a wide range. It became even more difficult to perform flaw detection while

[Purpose of the invention]

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an array type probe in which the probe surface can be easily brought into close contact with the shape of the object to be inspected.

[Summary of the invention]

That is, in order to achieve the above object, the present invention consists of a plurality of ultrasonic transducers arranged in parallel, and an electronic system that arbitrarily deflects and focuses an ultrasonic beam by controlling the transmission/reception timing of each ultrasonic transducer. In an array-type probe used in scanning ultrasonic flaw detection, multiple sets of ultrasonic transducers are arranged closely in parallel, and the distance between each ultrasonic transducer is Each probe is connected with a connecting material so that it can be bent and deformed, making it possible to increase the aperture size of the probe with a small number of ultrasonic transducers, thereby improving the directivity at the focal point of the ultrasonic beam. In addition, the probe can be bent and deformed by the connecting material, so that the probe can be brought into contact with the entire structure even if the structure has a curved surface. do.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows an example of the configuration of the array type probe of the present invention. is an array-type probe, and this array-type probe 1 is composed of N ultrasonic transducer sets 2(1) to 1 (Nl) arranged in parallel, and each set is composed of the M ultrasonic transducers &(11,...3 (MJ
It consists of

Here, each ultrasonic transducer set mentioned above! (13,...2) The ultrasonic transducer J (Il
a coating material 5 for protecting the oscillator (l...3) and improving acoustic coupling with the object to be inspected 4; A damping material 6 is attached. ? Furthermore, a flexible connecting rod 7 is attached between each ultrasonic transducer set 2 (F, . . . 2 (N). The connecting rod 7 (1).

. . 2 (N) is kept constant, and each ultrasonic transducer wire is configured to freely cause relative positional displacement in the group arrangement direction. That is, in the embodiment of the present invention, rotatable hinges 8 are provided at both ends of the connecting rod 7 to connect the ultrasonic transducer wire.
It is also possible to use a flexible spring material or rubber material instead.

The present invention may also be constructed as shown in FIG. That is,
In order to make the length of the connecting rod 7 expandable and retractable,
(As shown in Figure 2, the connecting rod 7 is provided with a 7971 part 9 and has a telescopic structure. By extending this cylinder part 9, the distribution of the ultrasonic transducer beam can be coarsened as shown in Figure 2 (aJ). It is possible to increase the apparent aperture size of the ultrasonic probe, or to reduce the aperture size of the probe as shown in Figure 2 (bJ) by shrinking the connecting rod 7 using the cylinder part 9. Here, an air or liquid cylinder can be used for the cylinder part 9.In addition, a threaded rod can be attached instead of the cylinder, and the length of the connecting rod can be adjusted freely by rotating it with a pulse motor or the like. If it is possible to change the distance between each transducer wire, it is also possible to electronically control the distance between each transducer wire.In this case, the relative distance between each string can be freely given, and each wire can be adjusted according to the relative distance. It is also possible to control the ultrasonic transmission/reception time timing to the ultrasonic transducer.

Next, the operation of this apparatus having the above structure will be explained with reference to FIG. FIG. 3(a) is an enlarged view of one array type probe 2 (iJ), and 2A is its aperture size, that is,
This is the width of the transmitting and receiving surface of the probe.

Usually, the array type probe 2 (ultrasonic transducers constituting II, 9 (11,, 9 (2) I...3 (target spacing d is
As shown in the formula below, the ultrasonic beam UB is
the desired direction θ. (UBIn indicates the main beam direction), ultrasonic waves are generated in directions other than the desired direction,
That is, it is limited in order to prevent the occurrence of grating lobes (J).

Here, λ is the wavelength of the ultrasonic wave determined by the frequency of the ultrasonic transducer used and the sound speed of the object to be inspected.

Therefore, in general, the transducer arrangement interval d of an array type probe is
cannot be large enough.

In other words, the width of the ultrasonic transducer must necessarily be smaller than d, and in order to increase the aperture size of the array probe,
It is necessary to arrange a large number of ultrasonic transducers.

On the other hand, the generation of grating lobe GE is caused by - The sound field directivity from the ultrasonic transducer is small and the sound spreads over a wide range inside the inspected object 4, and when the sound field directivity is strong. The generation of grating lobes GJ is also suppressed.

According to the array type probe of the present invention, each ultrasonic transducer beam 2
(IJ, 2 (2J, . . . 2 (N)) The ultrasonic beam UB due to It is possible to suppress the generation of grating lobes between the transducer strings.In addition, the ultrasonic transducer beams zQ), !(2J
,... Each ultrasonic beam UB according to 2 (b) is
In order to focus on one desired flaw detection area TG as shown in Figure (bJ), the desired area
A good ultrasonic sound field at G is generated. Therefore, this makes it possible to reduce the number of transducers constituting the probe and increase the probe aperture size for two people compared to the conventional array type probe.

One of the effects of increasing the probe aperture size is that the focusing strength D = A when focusing ultrasonic waves
m/λF is improved, and the directivity angle near the focal point β=
gin-'' (λ/2A) becomes smaller, thereby improving the detectability and resolution of the ultrasonic beam. Note that F is the ultrasonic focusing distance.

Another feature of the present invention is that, as shown in FIG. 4, each ultrasonic transducer beam 2(1) to 2(N) is
Even if the inspected object 4 is not flat, it can be brought into contact with the inspected object 4 according to its surface shape. Therefore, in this case, each ultrasonic transducer A6.2 (1
1,...,2 (Although the directions of Nl vary, any transducer beam can be brought into contact with the object 4 to be inspected, so the shape of the probe contact surface of the object 4 to be inspected is known in advance. According to the arrangement position of the array type probe of the present invention, each transducer s of each transducer line 2 (G), . . . 2 (N)
By controlling the timing of ultrasonic liquid transmission and reception by (11e...3), desired direction and area TG
This makes it possible to perform ultrasonic flaw detection by deflecting and focusing the ultrasonic beam.

Furthermore, the feature of the present invention is that each ultrasonic transducer set X (X>*...2
(The relative distance interval of NJ can be changed freely.The advantages of doing so are as follows.

That is, as shown in Fig. 5(a) and (bJ), the same ultrasonic beam width a is used when detecting short and long distances.
In this case, the aperture size of the probe 1 is given by the following equation.

A=λT/(a cos' θ0)・・・・・・
(2) That is, the ultrasonic beam UB is focused at a depth T from the surface of the object 4 to be inspected. If the deflection is performed by deflecting by a degree, the depth T and the deflection angle θ. It can be seen that the larger the opening size, the larger the opening size and the need for two people. Conversely, if the probe aperture size is changed according to the above formula, it is possible to obtain the same ultrasonic sound field characteristics in all regions of the object to be inspected 4. Therefore, as shown in FIG. With such an array type probe having a structure in which the distance between the ultrasonic transducer strings is variable, if the ultrasonic probe aperture size is set according to the second equation, it is possible to significantly improve flaw detection accuracy.

In addition, in the probe of the present invention, two peaks of ultrasonic transducers have an interval d.
Because the three ultrasonic transducers are arranged in series, the aperture dimensions of the two probes 1 do not substantially match, but they can be easily corrected experimentally or analytically. It is possible.

In the embodiments of the present invention, only an example in which the array type probe is used as a one-probe method is shown, but the array type probe of the present invention may be used as a split type or two-probe type probe. It is also possible to use That is, each ultrasonic transducer set 2 (
1) to J (Nl), any one or more sets are used as transmitting probes, and the other sets are used as receiving probes.

Further, in the embodiments of the present invention, each ultrasonic transducer set is composed of the same number of ultrasonic transducers, but it does not necessarily have to be the same number of ultrasonic transducers. In particular, the number of ultrasonic transducers in each set is different, each set is treated as an individual probe, and the ultrasonic beam from each transducer line has the same ultrasonic beam focal point width in the desired flaw detection area. (focal width)
By giving a, the flaw detection accuracy can be further improved.

Note that the present invention is not limited to the embodiments described above and shown in the drawings, and can be implemented with appropriate modifications within the scope of the gist thereof. Needless to say, the present invention can be similarly applied to array type vibrators in the form of disks and discs.

As described above, according to the array type probe of the present invention, the aperture size of the array type probe can be made large with a small number of transducers, so it is easy to improve the directivity at the focal point of ultrasonic waves. becomes.

Further, since the array type probe of the present invention can be freely deformed, it can easily and uniformly contact even curved structural members, and its flaw detection ability is greatly improved.

Furthermore, since the aperture size of the probe can be changed freely, it becomes possible to detect flaws from long distances to short distances with a desired ultrasonic beam, improving the application performance of array type probes. .

〔Effect of the invention〕

As described in detail above, the present invention consists of a plurality of ultrasonic transducers arranged in parallel, and by controlling the transmission/reception timing of each of these ultrasonic transducers, an electronic beam can be directed and focused as desired. In an array type probe used in scanning ultrasonic flaw detection, a plurality of ultrasonic transducers are arranged closely in parallel, and the number of ultrasonic transducers is arranged roughly, and the distance between each ultrasonic transducer string is Since each structure is connected with a connecting material so that it can be bent and deformed, the aperture size of the probe can be made large with a small number of ultrasonic transducers, which is inexpensive and has good directivity at the focal point of the ultrasonic beam. In addition to improving flaw detection accuracy by suppressing the generation of grating lobes, the probe of this device can be bent and deformed, so it has a curved shape. The probe can be brought into contact with the entire structure of the structural member, making flaw detection possible.Also, since the length of the connecting material can be varied, the probe aperture size can be adjusted to correspond to the flaw detection depth. It is possible to provide an array type probe having excellent features such as being able to obtain good flaw detection accuracy even at different depths.

[Brief explanation of the drawing]

Figure 1 (al) (bl is a diagram showing a configuration example of the array type probe of the present invention, Figure 2 (a) (bJ is a diagram showing the state of aperture change of the array type probe of the present invention, Figure 3 Figures (a) and (b) are diagrams for explaining the present invention in detail, Figure 4 is a diagram showing the state of contact of the array type probe of the present invention with an object to be inspected, and Figure 5 (a) ( b) is a diagram illustrating the present invention in detail. 1... Array type probe, 2 (11-2(N)... Transducer set, 3(1)-3)... Ultrasonic transducer, 4...
・Object to be inspected, 5... Coating material, 6... Damping material, 7... Connecting rod, 8... Hinge, 9... Cylinder. Applicant's representative Patent attorney Takehiko Suzue Figure 3 (a) 2 (i) Figure 4 Figure 5 (a) (b)

Claims (1)

[Claims] 11) Electronic scanning ultrasound, which consists of a plurality of ultrasonic transducers arranged in parallel, and allows the ultrasonic beam to be arbitrarily deflected and focused by controlling the transmission and reception timing of each ultrasonic transducer. In array-type probes used in flaw detection, multiple sets of ultrasonic transducers are arranged closely in parallel, and each ultrasonic transducer string is connected with a connecting material. An array type probe characterized by being connected so that it can be bent and deformed. (2) The array type probe according to claim 1, wherein the connecting member is formed of a rod-shaped body whose both ends are pivotally supported by hinges. (3) The array type probe according to claim 1, wherein the connecting member is formed of a spring. (4) The array type probe according to claim 1, wherein the connecting member is made of a rubber material. (5) The array type probe according to claim 1, wherein the length of the connecting member can be variably adjusted. (6) The play-type probe according to claim 5, wherein the connecting member is configured to be variably adjustable in length using a cylinder device.