JPS629267A - Ultrasonic test equipment - Google Patents

Abstract

PURPOSE:To improve the precision of flaw detection by detecting the relative speed between an ultrasonic test equipment and a body to be detected by a detecting means and converting it into an electric signal, and controlling the rotating speed of a driving means by a control means on the basis of the electric signal. CONSTITUTION:An ultrasonic transducer 3 is fixed to a center fixation shaft 2 fixed to the main body of the ultrasonic test equipment through a fitting member 1. Further, tire side members 4a and 4b are fixed rotatably on the shaft 2 through bearings 5a and 5b. Nearly cylindrical urethane 6 is fixed as a tire outer peripheral part is fixed nearby outer peripheries of the members 4a and 4b and an ultrasonic transmission medium 8 is held in the tire 7 consisting of the urethane 6 and members 4a and 4b watertightly with a seal 9. An ultrasonic wave 10 transmitted by the transducer 3 is propagated in the medium 8 to enter the object body 11 through the tire outer peripheral part made of the urethane 6, and then propagated in the object body; and a reflected wave from the object body 11 is detected by the transducer 3 and a signal analyzing device analyzes the presence, kind, etc., of a defect.

Description

DETAILED DESCRIPTION OF THE INVENTION a. Field of Industrial Application The present invention relates to an ultrasonic flaw detection device, and particularly to a tire-type ultrasonic flaw detection device.

b. Conventional technology When performing flaw detection using ultrasonic waves, when there is air, etc. between the ultrasonic transducer and the test object, a change in acoustic impedance occurs in the ultrasonic propagation path, and this impedance mismatch causes a change in acoustic impedance. reflection of ultrasound waves occurs at the interface. That is, ultrasonic waves are not efficiently transmitted from the ultrasonic transducer to the test object. To avoid this, there is an immersion flaw detection device that fills the space between the ultrasonic transducer and the test object with a liquid such as water instead of air to reduce changes in acoustic impedance.

Immersion type flaw detection equipment is accurate flaw detection equipment, but for flaw detection on continuously manufactured steel materials or rails, an immersion tank or the like is required to hold liquid, making the equipment large-scale and complicated.

Tire-type ultrasonic flaw detection devices based on the same principle as immersion-type flaw detection devices are known for detecting flaws in continuously manufactured steel materials or rails. This consists of a tire made of urethane or the like that rotates in close contact with the surface of a running steel plate, which is the test object, in which a liquid medium as an ultrasonic propagation medium and an ultrasonic transducer are placed. The ultrasonic waves transmitted from the ultrasonic transducer are sent into the test object through the liquid medium and the tire, and flaw detection is performed by detecting the reflected ultrasonic waves from defects and the like.

Problems to be Solved by the C0 Invention The accuracy of ultrasonic flaw detection is limited by the wavelength of the ultrasonic waves. In other words, increasing the frequency of ultrasonic waves improves the accuracy of ultrasonic flaw detection.

However, since ultrasonic waves are significantly attenuated in polymeric compounds such as urethane, there is a problem in that the thickness of the tire must be reduced in order to efficiently send ultrasonic waves to the test object.

Furthermore, in recent years, with improvements in manufacturing technology, the production speed of continuously manufactured steel materials has increased, and the relative speed between the test object and tire flaw detection equipment has increased.

Also, in rail flaw detection, the above-mentioned relative speed is required to be high in order to improve flaw detection efficiency.

In this case, the rotational speed of the tires becomes very high, and the rotation of the tires may not be able to follow the speed of the test object, especially when the speed of the test object changes. Simply causing the rotation of the tire to follow the speed of the test object cannot be achieved by creating a tight bond between the tire and the test object. However, in this case, the thickness of the tire inevitably increases, making it difficult to improve the accuracy of ultrasonic flaw detection.

SUMMARY OF THE INVENTION An object of the present invention is to provide an ultrasonic flaw detection apparatus that satisfies the contradictory demands of improving the accuracy of ultrasonic flaw detection and increasing the speed of flaw detection.

Means for Solving the d0 Problem The above problem consists of a fixed central shaft, an ultrasonic transducer fixed to the fixed central shaft, a tire rotatably and watertightly attached to the fixed central shaft, In a tire-type ultrasonic flaw detection device comprising a liquid as an ultrasonic propagation medium held between a fixed central shaft and a tire, a detection means separate from the tire for detecting the relative speed of the ultrasonic flaw detection device and a test object. The problem has been solved by an ultrasonic flaw detection apparatus including a drive means for rotationally driving the tire, and a control means for controlling the rotational speed of the drive means so that the peripheral speed of the tire is equal to the relative speed.

e. Detecting the relative speed of the ultrasonic flaw detection device and the test object using the detection means and converting it into an electrical signal. The rotational speed of the drive means is controlled by the control means based on the electric signal. As a result, the outer peripheral speed of the tire is always equal to the above-mentioned relative speed, that is, there is no "slip" between the outer peripheral surface of the tire and the surface of the test object.

In the tire-type ultrasonic flaw detection device according to the present invention, there is no need to rotate the tire while strongly pressing it against the test object in order to prevent the above-mentioned "slip", and therefore the wall thickness of the tire can be reduced, and this As a result, there is little attenuation even when using ultrasonic waves in the high frequency range.

f. Embodiment FIG. 1 is an elevational sectional view of a preferred embodiment of the tire-type ultrasonic flaw detection apparatus according to the present invention, and FIG. 2 is a conceptual top view of the tire-type ultrasonic flaw detection apparatus of FIG. 1.

An ultrasonic transducer 3 is fixed to a fixed central shaft 2 fixed to the main body (not shown) of the ultrasonic flaw detection device via a member 1 using conventional fixing means (the fixing means is shown in the figure). Furthermore, tire side members 4a, 4b are rotatably fixed to the fixed central shaft 2 via bearings 5a, 5b. A substantially cylindrical urethane 6 as a tire outer periphery 6 is fixed near the outer periphery of the tire side members 4a, 4b, and the urethane 6, the tire side members 4a, 4
An ultrasonic propagation medium 8 (for example, water or oil) is held watertight by a seal 9 in a tire 7 consisting of a tire 7 . The liquid used as the ultrasound propagation medium is usually water or oil.

The ultrasonic waves 10 transmitted from the ultrasonic transducer 3 propagate in the medium 8, pass through the tire outer circumference 6 made of urethane, enter the test object 1), and propagate therein. Note that the direction of the ultrasonic beam can be changed by changing the orientation of the ultrasonic transducer.

In this example, the test object 1) is a thin steel plate, and the ultrasonic wave propagates through the test object while undergoing multiple reflections as shown in the figure. The reflected wave from the test object 1) is detected by an ultrasonic transducer, and the presence of one type of defect is analyzed by a signal analyzer. Note that the test object is not limited to thin plates, and can also be used for flaw detection on rails and the like.

The tire side member 4b is configured such that the tire outer peripheral speed matches the relative speed V of the ultrasonic flaw detection device and the test object 1).
It is rotationally driven by a driving means 12. The above relative speed V
The attachment supporting the tire 7 is obtained as an output signal (analog signal or digital signal) of the rotational speed detector 14 that detects the rotational speed of the speed detection tire 13 attached to the member 1. Note that the speed detection tire 13 is pressed against the test object 1) with a sufficiently strong force so that the speed detection tire 13 rotates according to the relative speed with the test object 1) without "slip". ing. The pressing means are shown in the figure.
Not yet. In order to withstand this pressing force, the speed detection tire 13 is preferably made of synthetic rubber or the like with high rigidity.

The output signal becomes an input signal to a control means (not shown), and the rotation speed of the drive means is controlled using the control means.

g0 Effects of the invention 1) The thickness of the tire can be reduced to about 0.67 mm, whereas in the prior art the wall thickness of the tire was required to be about 4 mm or more. As a result, the frequency of the ultrasonic waves can be increased from about 2 MHz in the prior art to about 2 in the IOM. Therefore, flaw detection accuracy is improved.

2) Since the speed detection means is separate from the tire, the contact pressure with the test object can be increased. Therefore, until the relative speed between the ultrasonic flaw detector and the test object is about 0 to 250 ■/sec,
The tire can be rotated to follow the movement of the subject without any "slip", which also improves flaw detection accuracy.

[Brief explanation of the drawing]

FIG. 1 is an elevational sectional view in a plane including an ultrasonic transducer of a preferred embodiment of the tire-type ultrasonic flaw detection device according to the present invention, and FIG. 2 is a conceptual top view of the embodiment of FIG. 1. . 2... Fixed center shaft, 3... Ultrasonic transducer, 4a, 4b... Tire side member, 6... Tire outer circumference, 7... Tire, 8... Ultrasonic propagation Medium, 10... Ultrasonic wave, 1)... Test object, 12... Driving means, 13... Tire for speed detection, 14... Rotational speed detector. j1) 1 Figure j IZ diagram Procedural amendment cap button 1, Display of the case 1985 Patent Order No. 148033 2, Name of the invention Ultrasonic flaw detection device 3, Person making the amendment Relationship to the case Patent applicant name (33B) Tokyo Keiki Co., Ltd. 4, Agent
107 (2 others) 5. Subject of amendment “Detailed description of the invention” in the specification
column. Correction details page 8, line 1 r250g+/5ecJ to r250s
Corrected to /winJ.

Claims (4)

[Claims] (1) A fixed central shaft, an ultrasonic transducer fixed to the fixed central shaft, a tire rotatably and watertightly attached to the fixed central shaft, and an ultrasonic wave held between the fixed central shaft and the tire. A tire-type ultrasonic flaw detection device comprising a liquid as a propagation medium, comprising: a detection means separate from the tire for detecting the relative speed of the ultrasonic flaw detection device and the test object; a drive means for rotationally driving the tire; An ultrasonic flaw detection apparatus characterized by comprising a control means for controlling the rotational speed of the driving means so that the outer circumferential speed of the tire becomes equal to the relative speed. (2) The ultrasonic flaw detection device according to claim (1), wherein the outer peripheral portion of the tire is made of urethane. (3) The ultrasonic flaw detection device according to claim (1), wherein the liquid is water or oil. (4) The detection means comprises a speed detection tire strongly pressed against the test object and a rotation speed detector that detects the rotation speed of the speed detection tire. ) The ultrasonic flaw detection device described in section 2.