PURPOSE: To prevent oil leakage and air invasion, and to improve the durability of a probe by using a magnetic seal as a seal member of the circumferential part of a revolving shaft.
CONSTITUTION: A transducer 2 executes an oscillating motion around a point (a) through a transfer mechanism 5 by rotation of a motor revolving shaft 4, and executes sector scanning by transmission and reception of an ultrasonic wave. In this case, a magnetic fluid 9 having matching acoustically with respect to a body to be inspected and a case 1 is packed in the case 1. Also, a magnetic seal 10 provided between a base 3 and the revolving shaft 4 is constituted by inserting an annular permanent magnet 10b between two annular pole pieces 10a, and a magnetic closed circuit is formed by an oil 9 existing between the revolving shaft 4. Accordingly, metallic fine particles in the oil 9 gather between the pole piece 10a and the revolving shaft 4, a tightly sealing action is generated, and leakage of the oil 9 to the outside of the case 1 and invasion of air into the case 1 are prevented.
FURUBIKI TAKAAKI
KOBAYASHI YOUZOU
