| 摘要 |
PROBLEM TO BE SOLVED: To allow stirring processing of a lot of object to be stirred even if a density of the object to be stirred is large by improving the upward scrape efficiency and the stirring efficiency of the object to be stirred and improving the strength and the wear resistance of screws.SOLUTION: A lot of projecting stripes 16 running along the outer circumference are distributively disposed on a carrying surface 15 of each screw 8, the projective stripes are disposed from the outer circumference toward the inner circumference in a lower carrying surface present in a prescribed range from the lower end of the carrying surface toward an upper part of a shaft to increase the number of the projecting stripes, a plurality of projecting stripes present in the vicinity of an outer circumferential part of them are extended upward, and on an upper carrying surface, the projecting stripes are disposed in the vicinity of the outer circumferential part to reduce the number of the projecting stripes. At that time, preferably, the projecting stripes are disposed in the whole area in the lower carrying surface, a part of the projecting stripes are shortened on the more inner circumference side, in an upper carrying surface in a prescribed range continuing from the carrying surface, the projecting stripes are disposed in only the vicinity of the outer circumferential part, in an upper carrying surface in a prescribed range continuing from the carrying surface, and no projecting surface is formed in an upper carrying surface continuing from the carrying surface. |
