MAGNETIC FLUX IRRADIATION UNIT

Japanese Patent JP3767820

B2

PROBLEM TO BE SOLVED: To prevent overheating of a core even if the flux density is high. SOLUTION: The magnetic flux irradiation unit is provided with a stick-like operating section 40 inserting a core into a solenoid coil 50 and having an operating end 41 in one end of the operating section 40 for directing magnetic flux outward and the other nonoperating end 42. The core is divided into a short piece 61 on the operating end 41 side, and a thick and long piece 62 on the nonoperating end 42 side. The short piece 61 and the long piece 52 are spaced apart from each other to ensure a gap 63, an inner channel 72 is formed in the long piece 62 in addition to an outer channel 71 in the outer surface thereof, a cooling means 70 for feeding coolant from the nonoperating end 42 side to the channels 71 and 72 is attached, and an extra winding section 51 is wound around the solenoid coil 50 on the operating end 41 side. Temperature rise is suppressed through control of heat generation density and direct forced cooling of an overheated section.