Rack bar and manufacturing method thereof

摘要

A rack bar of a power steering unit for a vehicle has improved bending strength. The rack bar includes a rod portion (11) which fits slidably into an oil seal (52) attached to a cylinder portion (50) of a power cylinder (51), and a rack portion (13) which is formed with the rod portion (11) through a connecting portion (12) and which meshes with a pinion (20). Quenching is applied to the rod portion (11) and to the rack portion (13), preferably under different conditions. The quenching applied to the rack portion (13) also is applied to at least a portion of the connecting portion (12).