Tool holder of machine tool

Abstract

A tool holder of a machine tool, wherein a holder rear end part is fixed to the front end part of the spindle of the machine tool, a tool receiving surface part () for receiving the rear end face of a shaft-like tool () fixed to a holder front end part so that a closed space in contact with the rear end face can be formed and mist cutting fluid passages () for leading mist cutting fluid fed from the front end part of the spindle to the closed space () are formed in a holder body at a center of rotation, and exhaust passages are formed for opening a part of the tool receiving surface part in contact with the closed space () to the atmosphere, whereby even when the shaft-like tool () is small in diameter and the amount of the mist cutting fluid flowing out to the atmosphere through a passage hole () in the shaft-like tool is small, the liquefied cutting fluid can be prevented from being accumulated in the mist cutting fluid passages by maintaining the flow velocity of the mist cutting fluid in the mist cutting fluid passages () at a proper level.