Clamping device with hydraulic clamping

A clamping device for clamping a workpiece or a tool and in particular for coupling the workpiece or the tool to a machine spindle, including:

• a) at least one clamping bush which extends around a central axis (M) and has at least one clamping surface for the workpiece or tool and
• b) at least one clamping body,
• c) wherein the clamping bush on a side remote from the clamping surface comprises at least one support surface which extends about the central axis along a helical line and at the same time is inclined at an angle of inclination (α) to a direction (Z) which is axial to the central axis (M),
• d) wherein the clamping body, on a side facing the clamping bush comprises at least one support surface which extends about the central axis (M) along a helical line and at the same time is inclined at an angle of inclination (α) to a direction (Z) which is axial to the central axis (M),
• e) wherein at least one of (i) the clamping body or (ii) the clamping bush includes at least one hydraulic chamber positioned in an interior thereof, the at least one hydraulic chamber being filled with a hydraulic medium,
• f) additionally including at least one displacement element in order to move the support surfaces, which face one another, of the clamping body and clamping bush into contact with one another by moving them slidingly towards one another as a result of an axial displacement movement along an axial displacement path (ΔZ) in the axial direction (Z), as a result of which a diameter of the clamping surface is modifiable in a direction (R) radial to the central axis (A), such that with a clamping surface already abutting against the workpiece a radial mechanical clamping force (FR) is generated between the clamping bush on the one hand, and workpiece on the other hand,
• g) additionally including at least one pressure generator in order to impinge upon the hydraulic medium in the at least one hydraulic chamber with hydraulic pressure (pH) which, with the support surfaces of clamping body and clamping bush lying one on top of the other, generates a radial hydraulic compressive force (FH) on the support surfaces of clamping body and clamping bush lying one on top of the other, wherein, as a result of the radial hydraulic compressive force (FH), with a clamping surface already abutting against the workpiece a radial hydraulic clamping force (FH) is generated between the clamping bush on the one hand, and workpiece on the other hand.