CLAMPING UNIT FOR A CHUCK OF A MACHINE-TOOL SPINDLE

The invention relates to a clamping unit for a chuck of a machine tool spindle. The clamping unit (10) for a chuck of a machine tool spindle contains a threaded shaft (12) for adjusting the clamping jaws of the chuck. The threaded shaft (12) is axially adjustable in the clamping unit (10) by means of a threaded nut (13) connected to a rotor (15) of a servomotor actuator (15, 18). An electrically actuable, releasable clutch (19, 20, 23) has a first clutch element (19), which is connected in a rotationally secure and axially displaceable manner to the threaded shaft (12), and a second clutch element (20), which cooperates with the first clutch element (19) and is connected in a rotationally secure manner to the rotor (15). When the clutch (19, 20, 23) is activated, the threaded shaft (12) and the threaded nut (13) are mutually connected in a rotationally secure manner and prevent axial displacement of the threaded shaft (12). 本发明涉及用于机床主轴的卡盘的夹紧单元。用于机床主轴的卡盘的夹紧单元（10）包括用于调节卡盘的夹紧爪的螺纹轴杆（12）。该螺纹轴杆（12）可借助连接到伺服马达致动器（15,