MAIN SPINDLE DEVICE OF MACHINE TOOL AND TOOL POT DEVICE OF TOOL MAGAZINE FOR AUTOMATIC TOOL REPLACING DEVICE

PROBLEM TO BE SOLVED: To provide a main spindle device used for automatic tool replacing without including imbalance factors and a tool pot device for an ATC tool magazine. SOLUTION: A tapered hole 11 for fitting and holding the tapered shank part 33 of a tool holder 31 to be pulled out is provided in the tip part of a main spindle 9 rotationally driven by a main spindle motor 19, a screw type drover 23 having a male screw part 27 in the center through-hole 21 of the main spindle 9 is provided, the male screw part 27 is engaged with the screw hole 41 of the tapered shank part 33 by the rotation of the drover 23 and thereby the tool holder 31 is chucked. In a tool pot device, a tool pot member 59 having a tool holder holding hole 57 for receiving the tool holder 31 to be pulled out is attached by a bellows member 55 and a clamping mechanism for fixing the tool holder 31 inserted into the tool holder holding hole 57 by the elastic deformation of a cylindrical and thin sleeve part 65 to be released is incorporated in the tool pot member 59.