| 摘要 |
PURPOSE:To prevent the axis of rotation of the ball mounted on the roller of a ball driving part from being eccentric and to accurately detect an extremely small defective waveform by forming a shaft and a bearing which supports the roller of ceramic. CONSTITUTION:The shaft 12 and bearing 13 of the roller 11 of the ball driving part where the ceramic ball 10 for the structure member of the object to be inspected is mounted and rotated and formed of ceramic. Consequently, the axis of rotation of the ball 10 is prevented from being eccentric owing to the wear between the shaft 12 and bearing 13 and the ultrasonic flaw inspection of an extremely small defect of the ball 10 becomes stable to improve the accuracy of the defect detection. Further, zirconia, silicon nitride, alumina, silicon carbide, etc., with >=1,200kg/mm<2> Knoop hardness are used preferably for the ball driving part as to wear resistance and corrosion resistance. |
