Shut-off nozzle with needle valve, injection device and injection molding machine

An injection device comprising:

• a heating cylinder;
• a screw provided in the heating cylinder;
• and
• a shut-off nozzle provided in the heating cylinder, the shut-off nozzle comprising:
• an injection nozzle in which a flow path is formed;
• a needle valve provided in the flow path coaxially with the injection nozzle, the needle valve being movable forward and backward in an axial direction;
• and
• a guide ring provided in the flow path,
• wherein the needle valve comprises a columnar shaft portion, and the guide ring is configured to guide the forward and backward movement of the needle valve at the shaft portion, and
• wherein the guide ring is fixed to the shaft portion of the needle valve and is configured to move forward and backward integrally with the needle valve when the needle valve moves forward and backward, with an outer peripheral portion of the guide ring sliding with respect to a bore of the flow path.

An injection molding machine comprising:

• a mold clamping device configured to clamp a mold;
• and
• an injection device configured to inject a resin, the injection device comprising:
• a heating cylinder;
• a screw provided in the heating cylinder;
• and
• a shut-off nozzle provided in the heating cylinder, the shut-off nozzle comprising:
• an injection nozzle in which a flow path is formed;
• a needle valve provided in the flow path coaxially with the injection nozzle, the needle valve being movable forward and backward in an axial direction;
• and
• a guide ring provided in the flow path,
• wherein the needle valve comprises a columnar shaft portion, and the guide ring is configured to guide the forward and backward movement of the needle valve at the shaft portion, and
• wherein the guide ring is fixed to the shaft portion of the needle valve and is configured to move forward and backward integrally with the needle valve when the needle valve moves forward and backward, with an outer peripheral portion of the guide ring sliding with respect to a bore of the flow path.