| 摘要 |
PURPOSE:To act exciting source force without using any mechanical mechanism by acting the electromagnetic force of coils upon the magnetic fluid sealed by a rubber sheet. CONSTITUTION:An outer case 10 of a cylindrical shape is mounted to a probe 1, and an exciting source body is put therein. The exciting source body consists of a thick-walled nonmagnetic cylindrical block 11, a rubber sheet 2 which is press-fixed thereto by way of an O-ring 12, a retaining member 13 with a cylindrical collar, an inner magnetic yoke 14, coil rings 4a, 4b wound to a bobbin 15 and an outer yoke 16. Magnetic fluid 3 is filled in the area encircled by the sheet 2 and the block 11. If electricity is conducted to the coil ring 4a, the entire part of the fluid 3 can be moved in an X direction and if it is conducted to the coil ring 4b, the fluid can be moved in -X direction. The water 5 in hole, too, moves in the X direction or -X direction without receiving any volume change. Hence, force is applied in the X or -X direction to the wall 6 in hole and only the S waves are radiated to the axial direction of the hole. |
