Less Loading Tube-Hydroforming Technology on Eccentric Shaft Part by Using Movable Die

Abstract

Eccentric shaft parts, such as crankshaft and camshaft, fabricated by thick-wall tube hydroforming are increasingly used in industries, especially air-conditioner and automotive industry. In hydroforming those thick-wall components, the very high internal pressure and incomplete filling of the die corner make the forming process become difficult. In this paper, a new less-loading hydroforming die with movable sleeve is introduced to form the tube-like eccentric shaft workpiece. The characteristic of less loading hydroforming is illustrated by comparing with the conventional one by using FE simulation. Some typical loading paths and defects in the new hydroforming process are also investigated. The results obtained from this paper demonstrated the internal pressure, die closing force and die stress can be significantly decreased, as well as the qualified tube-like eccentric shaft workpiece can be formed by using the new movable die hydroforming.