| 摘要 |
PROBLEM TO BE SOLVED: To mold without engulfing bubbles by providing a sprue directly communicating with a communicating portion of a short tube body forming part with a spiral guide path forming part. SOLUTION: A pair of inner molds 22 are symmetrical, and each has a collar part 221, a short tube body inner surface forming part 222, a spiral guide path surface forming part 223 and a slide surface 224. An outer diameter of the part 221 is the same as an inner diameter of an outer mold 21. An outer diameter of the part 222 is smaller by twice as large as a tubular wall of a short tube with an inner surface guide path to be molded than the inner diameter of the mold 21. When the pair of the molds 22 are slid on slide surfaces 224 of opposite molds 22 in the mold 21 and closed, and the parts 221 are engaged with both ends of the mold 21. Then, the short tube body forming part for the tubular wall of the tube with the guide path to be molded is formed between inner surfaces of the mold 21 and the parts 222, and the spiral guide path forming part is formed between the opposed guide path forming parts 223. In the case of injection molding, molten resin via a sprue 211 is sequentially filled while urging the air therein. Thus, it can be molded without engulfing bubbles. |
