Direct-pressure type mold clamping mechanism of an injection- molding machine

摘要

A direct-pressure type mold clamping apparatus of an injection- molding machine, capable of performing high-speed mold closing and opening operations and of producing a required mold clamping force, without the use of a large-sized motor, is driven by two motors. The mold clamping apparatus includes a ball screw (6) engaging a ball nut (7) which is movable in unison with a movable platen (1). The ball screw is coupled to a servomotor (10) through a transmission mechanism (8, 9, 11, 17), and is also coupled to an induction motor (12) through the transmission mechanism, a speed reducer (14), and a clutch (15). A numerical control unit (20) controls the servomotor, the induction motor, and the clutch. After the movable platen, drive by the servomotor, is moved at high speed to a die touch position, the movable platen is driven to a set mold clamping force producing position with a greater driving force, by both the servomotor and the induction motor. When the movable platen reaches the set clamping force producing position, the induction motor is braked by means of a braking system (13), so that the movable platen is locked to the foresaid position, thereupon the required mold clamping force is produced.