COOLING DEVICE FOR ROTARY MAIN SPINDLE

PURPOSE:To prevent the seizure of a rotary shaft by forming a rotary main spindle to a hollow form, inserting a fixed shaft through a fine gap in the hollow part, and cooling the fixed shaft by a cooling means, and absorbing the generated heat of the rotary main spindle to the fixed shaft through an air layer which exists in the gap, together by radiation. CONSTITUTION:The revolution main spindle 1 of a machine tool, etc., is supported on an outer cylinder 3 through a bearing 2 (radial roll bearing 2 and a thrust bearing 2b), and the outer cylinder 3 is supported on a housing 4. As for a cooling device 10 for the revolution main spindle 1, a fixed shaft 12 is inserted, leaving a fine gap (a) in the hollow hole 11 of the revolution main spindle 1 which is formed in a hollow form, and the fixed shaft 12 is cooled by a cooling means 13. The cooling means 13 consists of a plurality of feeding passages 14a formed on the outer peripheral side of the fixed shaft 12 and a common feedback passage 14b formed at the center of the fixed shaft 12, and cools the main spindle 1 in the course where the cooling water supplied from a coupling 15b flows out from a coupling 15b through the passages 14a,...14b.