| 摘要 |
PROBLEM TO BE SOLVED: To reduce the thermal deformation of a ball screw by heating by boring a coolant passage in a ball screw nut screwed to the ball screw, circulatorily feeding a coolant into the coolant passage, and directly cooling the ball screw nut. SOLUTION: A moving body 15 is fitted to a ball screw nut 19 screwed to a ball screw provided on a base, and the ball screw is rotated by a drive motor 23 to move the moving body 15 in this machine tool. A nut coolant passing hole 53 is bored near the ball rolling groove of the ball screw nut 19 fitted to the moving body 15, and a coolant from a coolant temperature adjusting device 61 is circulatorily fed to the nut coolant passing hole 53 to directly cool the heating section of the ball screw nut 19. A cooling hole 1a is formed at the center axis portion of a ball screw shaft 1, and the coolant is fed into it for temperature control. The uniform temperature control of the ball screw shaft 1 and the ball screw nut 19 is accurately made, and the precision of ball screw feed can be improved.
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