Mold clamping device, method of increasing/decreasing pressure for such device, and mold releasing method

摘要

A stationary platen (14) and a movable platen (18), which are connected with each other by tie rods (28), to which metallic molds are respectively attached, are opened and closed by an electrically driven ball screw mechanism. The movable platen is composed of a platen body and a pressure plate (304) attached to the platen body which can be contacted with and separated from the platen body. Between the movable platen and the pressure plate, clamping is conducted by the expansion and contraction of a bladder (318) into which hydraulic oil for clamping can be introduced. The bladder houses an insert die (320), the shape of which is identical with an internal shape of the bladder, and a hydraulic oil path is formed in the insert die. While a ball screw member (102) of an electrically driven ball screw mechanism is being supported being capable of moving in the axial direction, a brake means (130) for restricting rotation is provided, and a mold releasing cylinder mechanism (116) is connected. The mold releasing cylinder mechanism is operated when it shares a hydraulic pressure supply source for supplying hydraulic pressure to the bladder and the hydraulic oil path is changed over.