| 摘要 |
PURPOSE:To enable manufacturing by either of turning processing or milling processing, by eliminating restraint on a production method of a screw by a size of a screw outside diameter and a groove form of a base part. CONSTITUTION:In a form of a groove of a base part 14 of a screw where raw materials are fed to a screw main body, a groove depth 4 is decreased gradually smoothly toward the outside diameter of the screw 2 from a groove trough diameter, a groove width of a part corresponding to a main flight of the screw 2 is fixed, in a deltalike part surrounded by a lead line 10 of 8 base part 14 and a perpendicular line 11 to a screw shaft, the groove width is narrowed gradually up to an end point of the groove and an area of an end part is formed small. |
