One-piece hollow camshafts and process for producing same

Abstract

A method for producing a hollow camshaft comprising i) forming a camshaft preform by providing a hollow metal pipe, expanding the hollow pipe at spaced longitudinal locations by applying pressurized fluid internally to the hollow pipe, axially compressing the hollow pipe during the expanding step to accumulate metal at the spaced longitudinal locations, the expanding and compressing steps forming a camshaft preform having cam preforms of associated predetermined widths in a longitudinal pipe direction; and ii) forming a final camshaft from the camshaft preform by axially compressing the camshaft preform while applying the pressurized fluid to reduce the predetermined widths of the cam preforms while shaping the camshaft preforms into the final camshaft, the final camshaft having cams of relatively smaller widths in the longitudinal direction than the predetermined widths of the cam preforms.

Dependencies are inferred from the claim text.