| 摘要 |
PURPOSE:To obtain the high flaw-detection sensitivity of an ultrasonic probe by a method wherein ultrasonic pulses which are transmitted from an ultrasonic vibrator are propagated only through an ultrasonic propagation medium and a tire. CONSTITUTION:A tire 11 which is attached to a fixed shaft 10 is made of butadiene-based rubber, and it is rolled and moved around the shaft 10 on the surface of a steel plate 5. An ultrasonic vibrator 15 which is composed of a filmlike polymer piezoelectric element is attached to the taper-shaped outer circumferential face of a holding utensil 14 which is fixed to the rear surface of the shaft 10, and a space between it and the tire 11 is filled with an ultrasonic propagation medium 16. Then, ultrasonic pulses which are transmitted radially from the vibrator 15 are propagated through the medium 16 and the tire 11, they impinge on the steel plate 5, they are propagated inside the steel plate 5 at an angle of refraction theta, they are reflected by a flaw 9, they are propagated inversely in their transmission route, and they are received by the vibrator 15. The flaw 9 in the steel plate 5 is detected on the basis of echoes of the received ultrasonic pulses. Since the ultrasonic pulses are propagated only through the medium 16 and the tire 11 and impinge on the steel plate 5 in this manner, their propagation route is short, and the attenuation amount of the ultrasonic pulses is reduced. As a result, the flaw-detection sensitivity of the title ultrasonic probe is enhanced. |
