Device and method to shape worked pieces

A device for machining a workpiece (4) to be shaped consisting of a rotationally symmetrical hollow body blank (3) and a main spindle (1.1) each having an axis which is the same as a machine main axis (x), said device comprising:

• at least one outer shaping tool (8) including one or more outer shaping rollers, said at least one outer shaping tool (8) configured for being radially positioned and radially moved corresponding to a predefined desired outer and inner contour of said workpiece (4) to be shaped, and further configured for being displaced in an axial direction along said machine main axis (x);
• an inner shaping tool (9) which is freely rotatably fixed to a holder (5), said inner shaping tool (9) configured for being completely inserted into a central region of said workpiece (4), such that an area of an outer contour (9.2) of said inner shaping tool (9) always engages a shaping zone in which an effective outer diameter of the inner shaping tool (9) is equal to or slightly smaller than a desired inner diameter of the workpiece 4, said inner shaping tool (9) being freely rotated about said machine main axis (x) by frictional interaction with between an outer contour (9.2) of said inner shaping tool (9) and an inner surface of said workpiece (4), said inner shaping tool (9) further configured for being displaced in an axial direction along said machine main axis (x) and wherein said inner shaping tool (9) is mounted so that said inner shaping tool (9) is configured to freely rotate about and coaxially with the machine main axis (x) of the main spindle (1.1), wherein the one or more outer shaping rollers of the at least one outer shaping tool (8) are configured to engage with an outer surface of the workpiece (4) in a region of the inner shaping tool (9) from externally against said outer surface of the workpiece (4), said inner shaping tool (9) having an axial length which is less than 50% of an axial length of the workpiece (4) to be shaped, wherein the inner shaping tool (9) has an axially profiled outer contour (9.2) configured to provide different effective inner shaping tool diameters, wherein the inner shaping tool (9) is configured to be axially moved and axially positioned relative to an axial position of the at least one outer shaping tool (8) in order to predefine an axial position of the shaping zone on the inner shaping tool (9) located between the inner shaping tool (9) and the at least one outer shaping tool (8) through axial positioning of the at least one outer shaping tool (8) relative to the inner shaping tool (9) so that, due to the different effective tool diameters of the outer contour (9.2) of the inner shaping tool (9), an inner diameter of the workpiece (4) is predefined through the relative axial position of the at least one outer shaping tool (8) and the inner shaping tool (9) relative to each other;
• an axially movable headstock (1) movable along said machine main axis (x), and wherein said axially movable headstock (1) includes a driven entrainment element (11) and a tailstock (2) with a receiving device formed as a centering element (7), said axially movable headstock (1) and said tailstock (2) configured to cooperate to maintain said workpiece (4) centered and axial along said machine main axis (x);
• and
• said centering element (7) comprising a tensioning device (14) with a pressure extension (10) guided centrally with respect to the machine main axis (x), wherein said tensioning device (14) with the pressure extension (10) is configured to hold the workpiece to be shaped (4) centered and braced axially along said machine main axis (x) between the driven entrainment element (11) and the centering element (7), so that the headstock (1) with rotating main spindle (1.1), the workpiece to be shaped (4) and the tailstock (2) form, due to a pre-stressing, one unit configured to be moved jointly through an axial force of a feed device (15) arranged on the headstock (1) with a controlled feed in the axial direction relative to the at least one outer shaping tool (8).