Canon Kabushiki Kaisha

Hirofumi Sugawara

Ryohei Inaba

Masaaki Kumamura

Yozo Tobo

Tadanobu Miyazaki

Shozo Kasai

Shojiro Danmoto

Mitsuo Arai

Norio Nikaido

Yozo Tohbo

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.

An injection molding apparatus uses motors to effect measuring and kneading of a material to be molded and injection driving. The amount of movement of a rotary shaft or rectilinearly moving means connected to a screw is detected by a sensor, and the driving of the volume measuring motor and the injection motor is effected by the output of the sensor.

Electrically driven type injection molding apparatus

An injection molding method uses motors to effect measuring and kneading of a material to be molded and injection driving. The amount of movement of a rotary shaft or rectilinearly moving means connected to a screw is detected by a sensor, and the driving of the volume measuring motor and the injection motor is effected by the output of the sensor.

Electrically driven type injection molding method

An injection molding apparatus includes an electrically driven injection apparatus in which a screw accommodated in a heating cylinder is driven by a motor. The injection apparatus includes a pressure detection device for detecting an injection pressure of the screw and a device for detecting a stroke of the screw. Speed control is first conducted until the preset packing rate which represents that a dwell process is almost started is obtained, and the remaining injection process and the dwell process are conducted using an output of the pressure detection device. If a volume of resin in the cylinder which is required to fill the cavity is obtained beforehand, a packing rate of the molding material in the cavity is obtained by detecting the screw stroke. A packing rate which represents that the dwell process is nearly started is preset, and speed control of the screw is conducted and the resin is thereby packed at a fixed injection rate until when that preset packing rate is obtained. In the remaining injection process and the subsequent dwell process, a desired screw thrust is obtained using the output of the pressure detection device which detects the injection pressure of the screw.

Growing community of inventors

Yokohama, Japan

Hirofumi Sugawara