The process sequence design of a power-assisted steering part

Abstract

Conventional and new forging processes of a power-steering worm blank are analyzed by the rigid–plastic finite element method. The conventional process contains three stages such as indentation, extrusion and upsetting, and was designed by a forming equipment expert. Process conditions such as reduction in area, extrusion angle and upsetting ratio are considered to prevent internal or geometrical defects. The results of simulation of the conventional forging process are summarized in terms of deformation patterns, load–stroke relationships and die pressures for each forming operation. Based on the simulation results of the current three-stage process, a power-steering worm blank forging process for improving the conventional process sequence is designed. The die pressures and forming loads of the proposed process are within the limit value, which was set by experts and the proposed process is found to be suitable for manufacturing the power-steering worm blank.