Electric spindle for numerical control machines

An electric spindle (1) for numerical control machines structured to lock and drive into rotation a tool (100) about a predetermined reference axis (A) locally coinciding with the longitudinal axis of the tool (2);

• the electric spindle (1) comprising an outer structural casing (2) which is structured to be rigidly attachable to a generic numerical control machine, and an electric motor (3) which is housed within the structural casing (2) and is provided with a drive shaft (4), which projects/emerges with its front end (4a) outside the structural casing (2) while remaining locally coaxial to the reference axis (A) of the electric spindle;
• the electric spindle (1) being characterized by also comprising:
• a thrust-bearing rotating bushing or sleeve (11) which is fitted in an axially rotatable manner on the front end (4a) of the drive shaft (4) via interposition of a first set of annular rolling bearings (12), and is maintained coaxial to the electric spindle reference axis (A) by a second set of annular rolling bearings (13) which are interposed between the rotating bushing or sleeve (11) and the structural casing (2);
• at least one disassemblable tool-holder head (5, 5′) which is structured to be fixable in a rigid and stable, though easily releasable manner to the front end (4a) of the drive shaft (4), is structured so as to accommodate and retain in a rigid and stable though easily releasable manner the shank (101) of a generic tool (100) for numerical control machines, and is finally provided with a peripheral crown (14) which is dimensioned/structured to stably abut, selectively and alternatively, on the front end (4a) of the drive shaft (4) or on the rotating thrust-bearing bushing or sleeve (11);
• and
• the electric spindle characterized by also comprising a tool locking and unlocking assembly (17) which is structured to selectively couple and lock/retain, in a rigid and stable though easily releasable manner, the shank (101) of the tool (100) for numerical control machines, so as to allow the disassemblable tool-holder head (5, 5′) to drive the tool (100) in rotation about the reference axis (A) of the electric spindle.