PURPOSE: To improve cooling efficiency of heat pipe, by providing liquid collecting grooves in the longitudinal direction and in the circumferential direction to the inner wall of the pipe in the cooling heat exchange region.
CONSTITUTION: The cooling medium is sealed in the sealed, hollow hole 19' provided in the shaft 3' of the rotor used for the rotary shaft of a motor, etc. The difference in stage is provided between the inner circumferential wall 19a' in the region of heating heat exchange and the inner circumferential wall 19b' in the cooling heat exchange region. A plurality of liquid collecting groove 33 in the circumferential direction and a liquid collecting groove 31 extending to the direction of the shaft are provided to the inner circumferential wall 19b' in the region of cooling heat ex- change, therefore, the cooling effect is improved.
KOYAMA NARIAKI
HARANO KEIICHI
