Canon Kabushiki Kaisha

Yozo Tohbo

Shozo Kasai

Norio Nikaido

Hirofumi Sugawara

A motor-driven vertical type injection molding apparatus with stable screw back pressure is provided with a simple structure. A plurality of guide shafts extending in the perpendicular direction are integrally provided in a lower base of an injection unit. A screw holding member is supported on the plurality of guide shafts to be movable in the perpendicular direction. The screw holding member is moved in the perpendicular direction by an injection motor through a ball screw mechanism. A screw extension shaft is integrally connected to the upper end of a screw. The screw extension shaft is supported on the screw holding member to be movable in the axial direction and rotatable. The screw extension shaft and screw are rotated by a measuring motor. In a measuring step, the dead weight of the screw holding member automatically resists the reactive force (screw back pressure) of a molten resin at a screw tip end portion.

Motor-driven vertical type injection molding apparatus

A screw holding member in which a screw is rotatably provided is guided in a vertical direction by two guide shafts. A ball screw is integrally provided on an upper part of the screw holding member through a load cell. A ball nut screwed to the ball screw is provided internally in an upper base through bearings. A second toothed pulley is fixed to the upper part of the ball nut. The ball nut is rotated by an injection motor through the second toothed pulley. The ball screw and the screw 44 are vertically driven by rotation of the ball nut. The second toothed pulley is formed with a through-hole into which the ball screw is loosely fitted, whereby the ball screw does not protrude from the second toothed pulley even when the ball screw rises.

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Yokohama, Japan

Yozo Tohbo