JP2917227B2 - Ultrasonic tomographic detection sensor and detection method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial applications]

The present invention relates to an ultrasonic tomographic detection sensor and method, and more particularly to an ultrasonic tomographic detection sensor and method applicable to nondestructive inspection of the inside of a structure and suitable for judging the quality of a welding nugget.

[Prior art]

In general, as a means of nondestructively inspecting the inside of a structure, there is a device that uses ultrasonic technology to find the quality of welding strength, internal scratches, pinholes, etc.For example, judging the strength of spot welds from nuggets Is being done. This is based on the fact that the strength of the spot weld depends on the diameter of the nugget, and the strength is determined by judging the size of the nugget diameter.Since the nugget cannot be visually recognized directly, ultrasonic exploration has been performed conventionally. ing. In order to determine the diameter of this type of nugget, a method of reflecting ultrasonic waves and a method of transmitting ultrasonic waves are known. In any case, a signal of an ultrasonic pulse emitted from an oscillation transducer is located at the center of the nugget. Since the signal has the maximum value and the reception sensitivity is high in the center, the signal at the center of the nugget is superior to other signals, and it is extremely difficult to obtain information on the periphery. Attempts have been made to sharpen the ultrasonic beam, subdivide the area to be measured, and more clearly grasp the information around the nugget.For this purpose, the beam is moved along the surface of the inspection unit. , Must also obtain the nugget position information. As described above, the current technology is limited to point measurement, and in actuality, a position sensor is used in combination to improve this.

[Problems to be solved by the invention]

As described above, the current ultrasonic sensor can obtain information only for each point, so it takes time for inspection, or even if it is used together with the position sensor, it requires skill in handling and moving it However, there has been a problem that both performance and operability are still unsatisfactory, such as wear of the tip of the ultrasonic sensor due to the above. An object of the present invention is to collect a plurality of ultrasonic receiving sensors in one sensor block, collect a collection of points on a surface to be measured instantaneously, and perform a planar treatment. It is an object of the present invention to provide an ultrasonic tomographic detection sensor and method capable of performing the above.

[Means for Solving the Problems]

In order to achieve the above object, the ultrasonic tomographic detection sensor according to the first configuration of the present invention is configured such that a contact end to an inspection object is formed in a narrow line shape and is expanded in a wedge shape outward. An ultrasonic wave propagating material comprising a formed sector-shaped cross-section block is provided, an oscillation transducer is attached to an outer surface of the propagating material, and a receiving transducer attached to the oscillation transducer is moved in a longitudinal direction of the linear tip. Are formed by providing a plurality of element rows composed of a plurality of elements arranged at a constant pitch along the line, and each element row is arranged to be a pitch gap position of another element row. Further, the ultrasonic rupture layer detecting method according to a second aspect of the present invention provides an ultrasonic wave propagation material comprising a sector-shaped block, an oscillation transducer provided on an outer surface of an arc of the ultrasonic wave propagation material, and the ultrasonic wave propagation material. A sensor comprising a receiving transducer provided with a plurality of element rows formed by a plurality of elements arranged at regular intervals along a direction orthogonal to the circumferential direction of the outer surface, the sensor comprising a tip end surface of the ultrasonic wave propagation material. The two-dimensional tomographic detection is performed by abutting on the inspection object and horizontally moving or rotating the sensor with respect to the object surface.

[Action]

According to the above configuration, the transducer for oscillation and reception is provided on the outer periphery of the ultrasonic wave propagation material processed into an arc shape. The focal point of the ultrasonic wave emitted from the circular oscillation transducer is determined by the diameter of the circular arc, and a fixed position (measurement point)
To fire. The emitted ultrasonic wave then emits from the measurement point, but this time it will diffuse back. However, although the receiving transducer is narrow in width to improve the resolution, it is long in the circumferential direction (in an arc shape), so that the reflected wave diffused from the closest focus (measuring point) is collected over a wide area, and the reflected wave Is extremely high. Then, in order to obtain the information in the length direction all at once, the receiving transducers are arranged in a line in an array. In this way, the receiving transducers are arranged linearly long, so that the oscillating transducers cover the receiving transducer group so that the group can receive the ultrasonic waves at a stroke. Must be long enough. Also, various problems such as crosstalk that may occur due to the large size of the oscillation transducer appear as if the signal wave is trailing, but there is no problem since this is cut by signal processing. In this case, another set of rows with the pitch shifted by a half is arranged to face the rows of receiving transducers arranged at a certain pitch. By doing so, it is possible to eliminate the gap between the receiving transducers and cover all information. It is also possible to add another two rows to shift by a quarter pitch to further improve the accuracy. The purpose is to move or rotate the sensor made in the above configuration for measurement. For example, by rotating, the linear information becomes a disk shape, which is more advantageous for visualization. As described above, by providing the oscillation / reception transducer in an arc shape, it is possible to determine the focal point in oscillation, and in reception, the received signal level becomes extremely high because diffused reflected waves are collected over a wide area,
Stable measurement is possible. Further, by arranging the transducers in one row, it is possible to obtain linear information, which was conventionally obtained only as "points". Further, in this linear information, information on the gap between the transducers is missing, and in order to prevent this, the transducers are arranged facing each other with the transducer pitch shifted by one half. This eliminates any missing parts,
It is possible to obtain all linear information. By moving this sensor, a rectangular planar shape is obtained, or by rotating it, disk-shaped information is obtained. By visualizing it as two-dimensional planar information from a line, it is easy to diagnose a measurement location. Becomes

【Example】

Hereinafter, specific embodiments of an ultrasonic tomographic detection sensor and method according to the present invention will be described in detail with reference to the drawings. 1 to 3 show an ultrasonic tomographic detection sensor according to an embodiment. This sensor 10 has an ultrasonic wave propagation material 12. This is a moderator that functions as a kind of lens that focuses by making it smaller than the ultrasonic wave propagation velocity in the inspection object, and is a solid block that has a uniform fan-shaped cross section formed by making the back part 14 an arc shape and a wedge shape The contact surface 16 to the member to be inspected is formed by cutting the tip partly. The curvature of the arc-shaped back portion 14 may be determined by sound ray theory. The arc surface back of the propagation material 12 formed as described above
An ultrasonic oscillation transducer 18 is attached to the center of 14 so as to be orthogonal to the circumferential direction thereof and along the longitudinal direction of the contact surface 16. This oscillation transducer 18
Is made of a fluorine-based or cyano-based polymer represented by polyvinylidene fluoride (PVDF), or a hybrid-type piezoplastic material composed of lead zirconate titanate (PZT), polyacetal, and rubber. It is affixed as a single band that occupies about 1/3 of the area of the arc surface back portion 14. On the other hand, receiving transducers 20 (20A, 10B) are provided in parallel with the oscillating transducer 18 on both sides of the arcuate surface back 14 to which the oscillating transducer 18 is attached. This receiving transducer 20 is likewise formed of a piezo plastic material,
On the receiving side, a plurality of transducer elements 22 are arranged in tandem at a constant pitch. That is, the element 22 is formed in a small strip shape,
These are arranged in a row at regular intervals, and are arranged in parallel on both sides with the central oscillation transducer 18 interposed therebetween. At this time, the receiving transducer 20 on one side
The gap of the pitch of the element 22 of A is inserted into the other transducer 20B.
Are arranged in a staggered manner so as to fill the elements 22. In the embodiment, the rows of the receiving transducers 20A and 20B on both sides are the elements 22.
And the width of the gap between the pitches are set to be the same, and the row of transducers 20A (20B) on one side is stuck with a pitch shifted by 1/2 with respect to the other row. , So that there is no leakage in the arrangement direction of the elements 22. As shown in FIG. 3, the ultrasonic tomographic detection sensor 10 configured as described above is used at a location where the welding nugget 26 of the inspection member 24 is formed, and the contact surface 16 is moved across the nugget 26. It is pressed against the surface of the inspection member 24. Ultrasonic waves are oscillated from the oscillating transducer 18 via a transmission medium such as water at the contact portion, and the reflected ultrasonic waves are detected via the plurality of receiving transducers 20. That is, the ultrasonic wave emitted from the oscillation transducer 18 is focused, passes through the contact surface 16, reaches the measurement location, and is reflected. The reflected signal also returns while diffusing back through contact surface 16. However, the outer surface of the propagation material 12 has an arc shape,
Since the element 22 also has an arc shape following this, the diffused ultrasonic wave is picked up in a wide range. At this time, since one element row is shifted by 1/2 pitch with respect to the other element row, the contact surface 1
All the information in the longitudinal direction of 6 can be detected. The detection signal is taken into the ultrasonic measuring device from each element 22 in the arrangement order of the receiving elements, and linear tomographic data in the transverse direction of the nugget 26 along the contact surface 16 can be detected at once. Next, from the state where the contact surface 16 of the sensor 10 is arranged in the direction crossing the nugget 26 as described above, the sensor 10 is horizontally moved or rotated around a point which is considered to be substantially the center of the nugget 26. ing. This moving or rotating operation amount is provided with a moving / rotating part in a sensor casing (not shown),
Desirably, the displacement or the rotation angle may be detected via an encoder, a distance sensor, or a rotation sensor and output to the ultrasonic measurement device. Then, the entire tomographic plane of the nugget 26 can be detected and output by taking in the linear tomographic data at the fixed angle position.
This output is binarized and processed by computer,
It can be visualized by displaying it as image data. As described above, according to this embodiment, a plurality of array elements in which the plurality of receiving transducer elements 22 are arranged in tandem at a constant pitch are provided, and both array elements 22 are arranged so as to fill the pitch gap in the other element. Therefore, the radial fault of the nugget 26 to be inspected can be detected at once. Then, by horizontally moving or rotating the sensor 10, a tomographic image of the entire nugget along the two-dimensional plane can be immediately detected and output. In particular, in this embodiment, the receiving transducers 20 are provided in a plurality of rows, and the elements of one row are arranged so as to fill the gap between the other pitches, so that there is no lack of detection and the detection resolution is increased. can do. That is, the surface area of the element 22 is made as small as possible to such an extent that the reception sensitivity does not decrease, and the elements 22 are arranged at regular intervals, and the resulting gap is filled by the other array element 22. As a result, the number of receiving transducer elements can be increased. Therefore, the resolution of the received signal is increased by the increase in the number of the elements 22, and the detection accuracy can be improved. FIG. 4 is a perspective view of the sensor 10A of the second embodiment. In this arrangement, the number of receiving transducer element rows is three, and the oscillating transducer 18 is arranged on one side edge of the arcuate back portion 14 of the ultrasonic wave propagation material 12. By doing so, the number of elements 22 per unit length can be increased to further increase the resolution. The oscillation transducer 18 need not be arranged at the center of the propagation material 12.

【The invention's effect】

As described above, according to the present invention, (1) the oscillation and reception signals can be used efficiently because the ultrasonic transducer is provided in an arc shape, and the measurement accuracy is further improved. (2) Since the oscillation transducer can have a large area, a large oscillation output can be obtained.
As described above, since large output oscillation is possible, the receiving transducer sufficiently functions even if it is small, and the resolution is improved. (3) By arranging a plurality of ultrasonic transducers in series, line information can be obtained instantaneously. (4) By arranging a plurality of transducers facing one another in series and displacing the other transducer row by a half pitch (or a half pitch if the number of rows is three or more). Missing information can be covered by an arrangement of transducers in only one row. (5) By measuring while moving or rotating the sensor created by the above transducer arrangement, disc-shaped information can be obtained.

[Brief description of the drawings]

FIG. 1 is a plan view of an ultrasonic detection sensor according to an embodiment, and FIG.
FIG. 3 is a sectional view, FIG. 3 is a perspective view, and FIG. 4 is a perspective view of the sensor according to the second embodiment. 10, 10A: Sensor, 12: Ultrasonic wave propagation agent, 14: Arc-shaped back part, 16: Contact surface, 18: Transducer for oscillation, 20 (20A, 20B): Transducer for reception, 22 ...
…element.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Yoshihiro Teranishi 600 Tanakacho, Akishima-shi, Tokyo Showa Aircraft Machinery Co., Ltd. (56) References JP-A-2-184755 (JP, A) (58) Field (Int.Cl. ⁶ , DB name) G01N 29/00-29/28

Claims (2)

(57) [Claims] 1. An ultrasonic wave propagating member comprising a fan-shaped cross-section block formed in a narrow line shape at the end of contact with an object to be inspected and expanded outwardly in a wedge shape. An oscillation transducer is adhered to the outer surface, and a plurality of element rows including a plurality of elements in which reception transducers provided in parallel with the oscillation transducer are arranged at a constant pitch along the longitudinal direction of the linear tip. An ultrasonic tomographic detection sensor characterized by being formed by providing rows, and each element row is arranged so as to be a pitch gap position of another element row. 2. An ultrasonic wave propagating member comprising a sector block, an oscillation transducer provided on an outer surface of an arc of the ultrasonic wave propagating member, and an ultrasonic transducer in a direction orthogonal to a circumferential direction of the outer surface of the ultrasonic wave propagating member. A sensor composed of a plurality of element arrays formed by a plurality of elements arranged at regular intervals along with a receiving transducer provided with a plurality of element rows, abutting the tip end surface of the ultrasonic wave propagation material on the inspection object, and contacting the surface of the object. In contrast, an ultrasonic tomographic detection method, wherein a tomographic detection on a two-dimensional plane is performed by horizontally moving or rotating the sensor.