Patent ID: 8753002

Claim:
A kneading segment, comprising: plural wing portions integrally formed along an axis of the kneading segment such that angles, around the axis, of the plural wing portions are shifted, wherein each of said wing portions comprises a leading end having a leading end surface which is a surface of the wing portion most distant from the axis and, at a part of the leading end of each wing portion where the wing leading end surface and a wing surface orthogonal to the axis connect with each other, a first flow surface continuing from the wing leading end surface and the wing surface is formed, and wherein at a part of a base end of each wing portion, where the orthogonal wing surface and a wing side surface of another wing portion adjacent to each wing portion connect with each other, a second flow surface continuing from the wing surface and the wing side surface is formed, wherein the first flow surface is formed by a convex-curved surface, and the second flow surface is formed by a concave-curved surface.