| 摘要 |
PROBLEM TO BE SOLVED: To increase a kneading effect of a resin. SOLUTION: Screw grooves 4 are partitioned into four sections in its width direction to strips 11, 12, 13 and 14. Ridges 11a to 14a and troughs 11b to 14b are respectively formed at the strips 11 to 14. The ridges 11a to 14a and the troughs 11b to 14b are alternately disposed at a predetermined interval, and three sets are formed within a range of one pitch of the grooves 4. The ridges 12a to 14a and the troughs 12b to 14b are disposed by delaying 30 deg. in phase to the ridge 11a and the trough 11b. |
