Patent ID: 6178633
Filing Date: 2001-01-30
Classification: F01C,Y10T

Abstract:
A method for producing a vane substantially in a flat rectangular parallelepiped shape having (a) two wide side surfaces opposing in the thickness direction, (b) two narrow side surfaces opposing in the width direction, (c) an as-cold-worked top surface having an arcuately projecting cross section in a plane perpendicular to the width direction, and (d) a bottom end surface opposing the top surface, both ends of said top surface in the width direction being bulging in a direction perpendicular to the width direction, comprising the steps of:(1) cold-working a flat bar by a roll die to provide the flat bar with substantially the same cross section as that of said vane, whereby the cold-worked flat bar has an arcuately projecting top surface with necessary precision in straightness and surface smoothness in a substantially as-cold-worked state;(2) shear-cutting said flat bar to a predetermined length in the thickness direction, thereby causing both ends of said top surface in the width direction to bulge in a direction perpendicular to the width direction; and(3) grinding both shear-cut surfaces of the resultant vane to such an extent that as high bulging as 1-10 .mu.m remains at both ends of said top surface.