MAIN SPINDLE COOLING DEVICE FOR MACHINE TOOL AND SPINDLE DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a main spindle cooling device having a structure obtaining high cooling efficiency in a rotary main spindle for a machine tool. SOLUTION: A cooling liquid passage 30 directly cooling a rotary main spindle 1 rotatably driven is provided in such a state as circulating from the rear of the rotary main spindle 1 via a front end part to the rearward again and spirally extended along the front-side outer circumference 37 of the rotary main spindle 1 pivoted by at least a front-side bearing 4. The circulation of the cooling liquid flowing through the cooling liquid passage 30 removes the heat generation from the front-side bearing 4 directly affecting the thermal expansion of the rotary main spindle 1 from the inside diameter side into the cooling liquid, effectively cools the inside-diameter side whole body of the front- side bearing 4, and effectively suppress the thermal expansion of the rotary main spindle 1.