| 摘要 |
PROBLEM TO BE SOLVED: To reduce a ball screw inertia of a rotating ball screw nut with a short time build-up at the time of starting operation of an injection molding machine by directly fixing by a bolt a hollow output shaft and a ball screw nut and simultaneously supporting a thrust bearing by a fixing nut. SOLUTION: Application of the current to a stator coil 50 causes a rotor core 49 to rotate, and the rotation is transmitted through an output shaft 3 to a ball screw nut 1. As a result, the ball screw nut 1 and a ball screw shaft 2 is tightened, thereby converting the rotary motion of the ball screw nut 1 in the direction indicated by an arrow A to the linear motion of the ball screw nut shaft 2 in the direction indicated by an arrow B, and the ball screw shaft 2 and a crosshead are forwarded or retreated by stroke Sb. If the crosshead is forwarded, a toggle mechanism advances and a movable platen is then forwarded, so as to close and clamping the mold. If the crosshead is retreated, the toggle mechanism is bent and the movable platen is retreated, so as to open the mold.
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