JPH0412268A - Arc array probe - Google Patents

Abstract

PURPOSE:To smoothly move the are array probe, and also, to decrease wear, to reuse the probe, and to exactly detect a moving distance by providing a roller so as to be rollable on a contact part to a body to be inspected of an acoustic lens. CONSTITUTION:As for a roller 6 provided on an acoustic lens 5, the radius of the outside periphery is the same as the radius of curvature of the lens 5 for forming a collimating lens, and also, the roller consists of a material by which the acoustic impedance approaches the lens 5 and a contact medium, and at the time of moving the arc array probe, it rolls through the surface 1a and the lens 5 and a medium 4, therefore, a focal area being equal to the lens 5 is formed, and also, an ultrasonic wave is propagated smoothly from the lens 5 to the roller 6. Simultaneously, frictional resistance against the surface 1a decreases and the probe is moved smoothly, and by an encoder 8 attached to a rotary shaft 7, a moving distance of the probe can be detected exactly. Also, even if the roller 6 is damaged, since it can be exchanged, expenses are cut down, and moreover, by changing it with a roller of a different sound speed, it is possible to vary a focal length and to expand the flaw detection range.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an arc array probe, and is particularly suitable for detecting internal defects in large turbine blades.
The present invention relates to an arc array probe suitable for performing ultrasonic flaw detection over a wide range smoothly and easily.

[Prior Art] The acoustic lens portion of a conventional general arc array probe will be explained with reference to FIGS. 3 to 5. Fig. 3 is a front view of an acoustic lens with a collimating lens formed in the contact part with the subject, Fig. 4 is a view taken from the IV-TV arrow in Fig. 3, and Fig. 5 shows no collimating lens formed. A front view of the acoustic lens is shown. In the figure, 1 is a subject, 1a is the surface of the subject 1, 2 is a fan-shaped acoustic lens, and a plurality of transducers 3 are arranged in a row on the arcuate surface forming the fan shape. A collimating lens 2a is formed in the part that contacts the surface 1a, and the collimating lens 2a has a curvature that bulges to the opposite side with a curvature corresponding to the circular arc surface. Line contact is made via a couplant 4 for efficient propagation. The collimating lens 2a is an acoustic lens 2' shown in FIG. 5 in which a collimating lens is not formed. While the ultrasonic beam diffuses rapidly when it deviates from the focal point F, it has the function of reducing the spread of the ultrasonic beam even when it deviates from the focal point F, and lengthening the area where the beam diameter is narrow near the focal point F (hereinafter referred to as the focal region). . Here, the couplant 4 is
collimating lens 2a and surface 1 to cover point P
a, and is applied to a width wider than the beam width of the ultrasonic wave emitted from the vibrator 3 on the applied surface.

Flaw detection on the surface 1a by the arc array probe equipped with the acoustic lens 2 or 2' includes electronic focusing, which focuses an ultrasonic beam by giving a predetermined delay time to each of the plurality of transducers 3 during transmission and reception; - This is carried out by moving the arc array probe or moving the object 1 while performing electronic scanning to select and switch the group of transducers.

[Problems to be Solved by the Invention] In the conventional arc array probe described above, it is possible to detect flaws in a fan-shaped range by the electronic scanning without moving the arc array probe, but this is limited. Stay within a small area. Therefore, in order to detect defects on a wider surface 1a, the arc array probe must be moved as described above, or the object 1 to be inspected must be moved. The surface 1a of 1 slides in contact with the surface 1a, causing friction at the contact portion. Of course, the contact portion contacts through the couplant 4 to avoid direct contact, but the surface 1a is not uniform due to differences in slope and surface roughness, as well as adhesion of dust, etc. The problem is that it is difficult to move smoothly due to the frictional resistance of the contact portion, and that the contact surface of the acoustic lens 2 or 2' of the arc array probe is worn out. Furthermore, the contact area is susceptible to cracks and cracks due to unexpected impact.
3- = 4- In such a case, there are problems such as not only the acoustic lens but also the entire arc array probe having to be replaced with a new one.

Furthermore, the moving distance of the arc array probe is essential for identifying the scanning position for the object 1 and the location of internal defects in the object 1, but conventionally the position of the arc array probe cannot be identified. It was not possible to accurately detect the distance traveled by objects, which was a problem in flaw detection.

In view of the above-mentioned problems of the prior art, the present invention changes the sliding friction of the contact part during the movement of the arc array probe to rolling friction, which not only enables smooth movement but also reduces wear of the contact part. Even if the arc array probe is damaged by an unexpected impact, the arc array probe can be used by simply replacing the contact part, and furthermore, the arc array probe can accurately detect the distance traveled by the arc array probe. The purpose is to provide a probe.

[Means for Solving the Problems] In order to achieve the above object, the present invention arranges a plurality of transducers in a row on the arcuate surface of a fan-shaped acoustic lens, and a contact portion of the acoustic lens with a subject. In an arc array probe in which a collimating lens is formed in the probe, the contact portion of the acoustic lens with the subject has an outer circumferential radius that is the same as the radius of curvature of the collimating lens, and has an acoustic impedance. A roller made of a material close to the acoustic lens and the couplant is provided so as to be able to roll through the subject and the acoustic lens via the couplant.

It is preferable that an encoder for detecting the moving distance of the arc array probe is attached to the rotating shaft of the rotatable roller, and the rollers have the same diameter.
In addition, it is preferable to provide a configuration in which the roller can be replaced with a roller having a different sound speed.

[Function] With the above configuration, when the arc array probe moves, the radius of the outer periphery is the same as the radius of curvature of the collimating lens, and the acoustic impedance is close to the acoustic lens and the couplant. Since the roller made of the same material rolls through the subject, the acoustic lens, and the couplant, a focal area equivalent to that of the acoustic lens forming the collimating lens is formed, and the subject Contact with the surface results in rolling friction, and the frictional resistance is significantly reduced compared to conventional sliding friction, allowing smooth movement and reducing wear on the contact portion (outer surface of the roller) with the subject. Of course, in order for the roller to roll, a gap is required between the roller and the acoustic lens for the roller to rotate, but a couplant with an acoustic impedance close to that of the roller and the acoustic lens is provided in the gap. By filling the gap and maintaining this state, reflection and scattering of ultrasonic waves in the gap can be prevented, and the ultrasonic waves can be propagated smoothly.

By attaching an encoder to the rotating shaft of the roller, the rotation of the roller is directly transmitted to the encoder, making it possible to accurately detect the moving distance of the arc array probe.

In addition, by attaching the rollers so that they can be replaced, even if the rollers are damaged, only the rollers can be replaced.Furthermore, it is also possible to change the focal length and expand the flaw detection range by replacing rollers with different sound speeds. .

[Example] An example of the present invention will be described with reference to FIGS. 1 and 2. In the drawings, the same reference numerals as in FIGS. 3 to 5 indicate the same parts. FIG. 1 is a front view of the acoustic lens section of the arc array probe, and FIG. 2 is a view taken along the line ■-■ in FIG. 1. In the figure, reference numeral 5 denotes a fan-shaped acoustic lens, and a plurality of transducers 3 are arranged in a row on the arcuate surface forming the fan shape, while a roller 6 on the subject 1 side is rotated in the direction of the arrow shown in the figure. A groove 5a is formed for possible fitting. The roller 6 is made of a material whose outer circumferential radius is the same as the radius of curvature of the collimating lens 2a shown in FIG. 3, and whose acoustic impedance is close to that of the acoustic lens 5 and the couplant 4. - As an example, there is a combination in which the acoustic lens 5 and the roller 6 are made of polystyrene resin, and the couplant material 4 is made of glycerin. A rotating shaft 7 is supported by the acoustic lens 5 and rotates together with the roller 6, and the roller 6 is connected to the surface 1a of the subject 1, the groove 5a of the acoustic lens 5, and the couplant 4.
It is possible to roll through. 8 is an encoder attached to the shaft end of the rotating shaft 7, which detects the moving distance of the arc array probe from the rotation angle of the roller 6. Reference numeral 9 denotes a tube for supplying the couplant material 4, which is connected to the roller 6 and the groove in order to prevent the couplant material 4 from adhering to the surface 1a due to the rotation of the roller 6 or being washed away due to the slope of the surface 1a and being reduced. 5a
and between the roller 6 and the surface 1a via a tube 9. Reference numeral 10 denotes a spray scraper that prevents dirt from entering the groove 5a by rotating the roller 6.

The movement of the arc array probe during scanning is controlled by roller 6.
In this case, the radius of the outer circumference of the roller 6 is the same as the radius of curvature of the collimating lens 2a, and the acoustic impedance is the same as the radius of curvature of the collimating lens 2a. Lens 5 and couplant 4
Since it is made of a material close to the collimating lens and rolls through the surface 1a, the acoustic lens 5, and the couplant material 4, a focal area equivalent to that of the acoustic lens forming the collimating lens is formed. The ultrasonic beam hits the roller 6 and the groove 5a.
Even if the ultrasonic waves propagate through the gap between the acoustic lens 5 and the roller 6, reflection and scattering of the ultrasonic waves in the gap is prevented, and the ultrasonic waves are smoothly propagated from the acoustic lens 5 to the roller 6.

At the same time, the contact with the surface 1a results in rolling friction, and the frictional resistance is significantly reduced compared to conventional sliding friction, allowing the arc array probe to move smoothly, and the outer peripheral surface of the roller 6 in contact with the subject 1. wear can also be reduced.

The encoder attached to the rotation shaft 7 of the roller 6 makes it possible to accurately detect the moving distance of the arc array probe from the rotation angle of the roller 6.

In addition, since the roller 6 is replaceably attached,
Even if the roller 6 is damaged, only the roller 6 can be replaced, making maintenance costs economical.Furthermore, the flaw detection range can be expanded by replacing the roller with a roller of a different sound speed to change the focal length. It becomes possible.

[Effects of the Invention] As explained above, the present invention provides a roller made of a material whose acoustic impedance is close to that of the acoustic lens at the contact portion of the acoustic lens with the subject via a couplant material whose acoustic impedance is also close to that of the acoustic lens. Since the roller is configured to be rotatable and replaceable with other rollers, and an encoder is attached to the rotating shaft of the roller, the contact area can be easily adjusted when the arc array probe moves without damaging the focal area. By changing sliding friction to rolling friction, it not only allows smooth movement but also reduces wear.Also, even if the contact part is damaged by impact, the arc array probe can be reused by simply replacing the contact part. Furthermore, various effects such as being able to accurately detect the moving distance of the arc array probe are achieved.

[Brief explanation of the drawing]

FIG. 1 is a front view showing an acoustic lens portion of an embodiment of the arc array probe of the present invention, and FIG. 2 is a view taken along the line nn in FIG. 1. Figure 3 is a front view of the acoustic lens in an arc array probe with a collimating lens formed in the contact area with the subject, Figure 4 is a view taken from the ■-■ arrow in Figure 3, and Figure 5 is a collimating lens. FIG. 3 is a front view of an acoustic lens in an arc array probe that does not form a mating lens. 1... Subject, 1a... Surface of subject, 2, 2'5
...acoustic lens, 2a...collimating lens, 3...vibrator, 4...couple material, 6...roller,
7...Rotation axis, 8...Encoder.

Claims (3)

[Claims] 1. In an arc array probe, in which a plurality of transducers are arranged in a row on the arcuate surface of a fan-shaped acoustic lens, and a collimating lens is formed at a contact portion of the acoustic lens with a subject, the acoustic lens A roller made of a material whose outer circumference radius is the same as the radius of curvature of the collimating lens and whose acoustic impedance is close to the acoustic lens and the couplant is placed at the contact portion with the subject and the acoustic lens. An arc array probe characterized in that it is provided so as to be able to roll through a couplant. 2. The arc array probe according to claim 1, wherein an encoder for detecting a moving distance of the arc array probe is attached to the rotating shaft of the rotatable roller. 3. Claim 1, wherein the rollable roller is replaceable with a roller having the same diameter and a different sound speed.
or the arc array probe described in 2.