TOOL SHANK AND WORKING SPINDLE OF MACHINE TOOL

PROBLEM TO BE SOLVED: To provide a tool shank and a working spindle of a machine tool withstanding a high-pressure liquid application and having high maintainability with simple and small structure. SOLUTION: The tool shank includes a tapered part 1 to be fitted in a tool attachment part 21, a center hole 2 formed on a rotation axis, a pull stud 3, a connection tube 4, and an elastic element 5. The pull stud 3 is inserted into the center hole 2 from a base end side to be fixed and includes a perforation 6 on the rotation axis; the connection tube 4 has an outer diameter of its end on a front end side formed greater than the outer diameter of other portions to form a tube head 7, is inserted into the perforation 6 from the front end side and slidable in an axial direction, and includes a seal member 8 on a periphery of the tube head 7; the seal member 8 is abutted on the inner peripheral surface of center hole 2; and the elastic element 5 is arranged inside the center hole 2 and biases the connection tube 4 to the base side. When a clamping unit 22 inside the working spindle of the machine tool clamps the tool shank, an end of the connection tube 4 on the base side is connected to an end of a torso section 23 of the clamping unit 22 on the front end side to form a channel. COPYRIGHT: (C)2010,JPO&INPIT