The Japan Steel Works, Ltd.

Takehiko Yanagiya

Yutaka Nakagawa

Toshio Toyoshima

Chikara Kawabe

Takahiro Sugahara

Yusuke Sugimori

A screw can be driven along an axial direction of a heating barrel and rotatable. An injection piston drives the screw along the axial direction. An injection hydraulic cylinder is partitioned into a first chamber in which pressured hydraulic oil for driving the injection piston is supplied and a second chamber from which hydraulic oil is discharged, and drives the injection piston in the axial direction by hydraulic pressure. A first oil discharge port is blocked by the injection piston when the injection piston advances to a holding pressure switching position. A second oil discharge port can discharge the hydraulic oil from the front chamber regardless of the position of the injection piston. The first oil discharge port is disposed at a position opposed to the first oil discharge port across a center axis of the injection hydraulic cylinder, and is connected to the first oil discharge port.

Injection apparatus

An injection piston drives a screw. An injection hydraulic cylinder drives the injection piston and is partitioned into first and second chambers. A first oil discharge port is disposed in the injection hydraulic cylinder to be blocked by a piston part when the piston part of the injection piston advances to a pressure-holding switching position, and discharges hydraulic oil from the second chamber. A second oil discharge port is disposed in the injection hydraulic cylinder to be capable of discharging hydraulic oil from the second chamber regardless of the position of the injection piston. The injection piston has first and second members. The joint of the first and second members is disposed at a position separated from an end of the piston part on a side of the second chamber by a predetermined distance.

An injection piston can be driven along an axial direction of a heating barrel. The injection piston is connected to a screw and drives the screw along the axial direction. An injection hydraulic cylinder drives the injection piston in the axial direction by pressure of hydraulic oil. Inside of the injection hydraulic cylinder being partitioned into a first chamber and a second chamber. An oil discharge port is provided in the injection hydraulic cylinder and discharges the hydraulic oil from the second chamber. A first valve is inserted in a path for discharging the hydraulic oil discharged from the second chamber. A second valve opens when the pressure of the provided oil is higher than a first threshold value. The first valve closes when the pressure of the hydraulic oil supplied through the second valve is applied to the first valve.

A flange is formed on a heating cylinder in a vicinity of a center in a longitudinal direction and a predetermined joining plate adheres to the flange. A flange plate is provided on a support frame. The joining plate is fixed to the flange plate to attach and detach freely, and the heating cylinder is caused to be supported by the support frame. Accordingly, movement in an axial direction and rotation of the heating cylinder are restricted. A guide portion for positioning during attachment and detachment is provided on one or both of the joining plate and the flange plate.

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Hiroshima, Japan

Takehiko Yanagiya