US 2009/0260467 A1 · STEERING RACK AND METHOD OF MANUFACTURING THE SAME

Abstract

When a punch is downwardly pressed, an inner circumferential surface of a first rack blank bites into a top surface of a second rack blank. A blank material upwardly flows due to a reaction force and is used to form rack teeth. Thus, a filling degree of the teeth with the material is enhanced. At the time when the forming of the rack teeth is finished, a gap is left between the inner circumferential surface of the first rack blank and the outer circumferential surface of the second rack blank. Thus, a die is not put into a sealed condition. Consequently, a forming load is small so that the lifetime of the die is lengthened. Also, the top surface of the second rack blank bites into a bore hole portion of the first rack blank so that the first rack blank and the second rack blank are joined together. Accordingly, the rigidity of the entire rack teeth is increased.

Claims24

Dependent claims

A method of manufacturing a steering rack, the method comprising:

providing a first rack blank in a form of a pipe having a bore hole, and a second rack blank or a mandrel having such a cross-sectional shape that a gap is provided between the second rack blank or the mandrel and an inner circumferential surface of the first rack blank;
inserting the second rack blank or the mandrel into the bore hole of the first rack blank;
restraining an outer circumferential surface of the first rack blank other than a rack teeth forming portion of the first rack blank by a first die;
forming rack teeth on the first rack blank by pressing a punch having a rack teeth shaped portion onto the rack teeth forming portion of the first rack blank, and causing the first rack blank to contact an outer circumferential surface of the second rack blank or the mandrel facing the rack teeth forming portion of the first rack blank;
and
allowing a blank material, which has been excluded in the forming the rack teeth, to flow into the gap between the inner circumferential surface of the first rack blank and the second rack blank or the mandrel such that the blank material is accommodated in the gap.

3 more elements

Dependencies are inferred from the claim text.

Steering rack and method of manufacturing the same

Life of this patent

Steering rack and method of manufacturing the same

Life of this patent

Abstract

Claims24