US Patent 7137180 Turret for machine tool

A turret for a machine tool is provided with: a turret body; a swiveling drum on which a tool holder for holding the rotating tool is mountable; a swiveling and indexing drive portion for swiveling the swiveling drum with a swiveling and indexing motor and for indexing any desired rotating tool; and a rotational driving motor, having a rotating shaft directed to an index position, incorporated into the swiveling drum and supported to the turret body. Under the condition that the rotating tool is indexed, a holder shaft of the tool holder of the rotating tool and the rotating shaft are coupled directly with each other and thereby the rotating tool is rotated by the rotational driving motor. Thus, when the rotating tool is drivingly rotated, the power transmission efficiency for rotational drive is high to thereby make it possible to reduce the heat generation, vibration and noise.