Drill unit with displaceable spindle - has two coaxial drive motors with hollow rotor shafts guided by bearings and rotated at different speeds to control spindle displacement

摘要

The drill unit has a longitudinally displaceable spindle (1) on which act two coaxial motors arranged in series. The motors have hollow rotor shafts (4, 5) guided in the machine housing (1) by roller bearings (6-9). both shafts encircle the spindle which does not turn relative to the shaft (5) of one motor (3) while the shaft (4) of the other motor (2) engages in the thread (17) of the spindle. The longitudinal movement of the spindle is regulated by the different rotational speeds of the motors (2, 3). The motors may be DC motors or AC asynchronous motors which, in the latter case, are braked by direct curr-in order to produce longitudinal movement of the sprindle.