| 摘要 |
PROBLEM TO BE SOLVED: To provide a backflow preventing ring in an injection molding machine which can minimize abrasion by sliding with a barrel inner surface and a screw chip used with the ring. SOLUTION: A screw chip main body 118 having a conical appearance is formed on the left side of the axial part 108 of the screw chip SCTP fitted to the tip part of an injection screw 102. A step part 108A is formed in the axial part. In the screw chip main body, crest parts 114 and groove parts 116 are formed alternately every 90 degrees. The member 112 of an abrasion resistant material is formed/arranged on the back side of the crest parts 114 and is contacted oppositely with a ring left end surface without a claw, and the ring left end surface is formed from the abrasion resistant material. In the contact part, rotational torque of a certain degree is given as transmission force through surface contact during metering rotation, but the ring, since its peripheral surface is contacted with the inner surface of the barrel 100, acts to decrease the transmission force. The transmission force also depends on force acting in the axial direction on the back of the ring. As a result, the rotation of the ring during metering is decreased sharply. COPYRIGHT: (C)2006,JPO&NCIPI
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