| 摘要 |
<p>Provided is a screw injection device that can be implemented at low cost and in which galling and seizing are not prone to occur on the outer surface of the check ring and the inner surface of the heating cylinder. A screw (8) is constituted from a screw body (31) on which a helical groove (8a) is formed, and a screw head (33) that is fixed on the tip of the screw body (31) via a small-diameter neck (32). A backflow-preventing device (40) is constituted from a check seat (41) that is fixed on the end of the screw body (31) toward the screw head attachment side, and a check ring (42) that is mounted on the neck (32) so as to be capable of rotating and moving forward and backward. On the end face of the screw head (33) on the check ring (42) side, multiple loose ball-fitting grooves (44) that have a deep groove section (44a) and a shallow groove section (44b) are formed. Balls (43) are accommodated in the respective loose ball-fitting grooves (44) so as to be capable of rolling, and are disposed between the screw head (33) and the check ring (42).</p> |
