Patent ID: 7112057

Claim:
An injection unit for a plastic injection molding machine, comprising: a screw ( 16 ), a motion spindle ( 10 ) as a first drive element, via which the screw ( 16 ) can be rotationally driven for the plasticization and is movable in the axial direction for the injection, a spindle nut ( 30 ) as second drive element, which is coupled to the motion spindle ( 10 ) via a motion screw thread ( 13 ), a large electric motor ( 20 ) which is arranged so as to be fixed to the frame and by which, while one drive element ( 10 , 30 ) is held against rotation, the other drive element ( 30 , 10 ) can be rotationally driven for moving the screw ( 16 ) during the injection, and a device ( 35 , 40 ) which is arranged so as to be fixed to the frame and by which a rotational speed of the one drive element ( 10 , 30 ) can be preset during the plasticization, said rotational speed being different from rotational speed at which the large electric motor ( 20 ) simultaneously drives the other drive element ( 30 10 ), wherein the drive element ( 10 , 30 ) held against rotation during the moving of the screw ( 16 ) for the injection is lockable by a releasable mechanical brake ( 40 ), and wherein a first clutch ( 60 ) which is effective for rotating the screw ( 16 ) during the plasticization is arranged between the motion spindle ( 10 ) and the large electric motor ( 20 ), and a second clutch ( 62 ) which is effective for moving the screw ( 16 ) during the injection is arranged between the spindle nut ( 30 ) and the large electric motor ( 20 ).