| 摘要 |
PURPOSE:To enlarge the rocking angle ratio of a probe to the end part and the center part of an ultrasonic flaw detection sector area by rocking a probe by a stud which moves in the axial direction by being electrically driven through a circular motion/linear motion converting mechanism. CONSTITUTION:With respect to a crank 11 driven by a motor 12 whose rotational angular velocity is constant, a small gear 8 being freely rotatable to the shaft of the crank 11, and a gear 8 which is fixed in a space and rotates the gear 8, a stud 7 executes a reciprocating linear motion along the diameter of a gear 9 through a circular motion/linear motion converting mechanism by an internal gear 9, etc. whose gear ratio is 2. In accordance with this motion, a rocking lever 6 rocks by centering a shaft 2, an ultrasonic probe 1 rocks and a sector area is brought to ultrasonic flaw detection. According to such a constitution, an rocking angular velocity of the probe 1 satisfies a condition of an expression I , a rocking angular velocity ratio of the end part and the center part of a sector flaw detecting area which is smaller than ''1'' becomes large, and a uniform ultrasonic flaw detection is executed. In the expression, theta, alpha, (a) and (b) denote a rotational angle of a motor, rocking angle of a lever 6, pitch circle radius of the gear 9, and a length of the lever 6, respectively.
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