Main spindle, in particular a high-speed milling spindle, for machine tools

In known main spindles, the automatic tool change is only possible when the main spindle is stopped. The novel main spindle is intended to permit the automatic tool change while rotating and is thereby intended to reduce the tool change time as auxiliary time, as a result of which the capacity and thus the productivity of the machining station is increased. For this reason, the housing (13) of the spindle head is arranged in a precentred manner free of play on the housing (12) of the trunk spindle (1), frictional driving rings (6; 7) and a peripheral groove (8) with compressed-air connection are coaxially arranged in the steep-angle taper (5) of the trunk spindle (1), a hydromechanical clamping device (28; 31; 32; 33) which corresponds with the housing (13) of the spindle head is provided in the housing (12) of the trunk spindle (1), the tool (9) and the end face of the trunk spindle (1) are each provided with a rack-tooth ring (26; 27) facing one another, and a peripheral gripper ring groove (10) is made in the housing (13) of the spindle head. This main spindle is suitable for machine tools with automatic tool change, in particular for complete machining stations with cutting tasks between roughing and precision machining.