Importance

Loading Importance Indicators...

Abstract

A die for forming a Y-form rack portion of a steering rack bar from a blank by forging in which the die has at least three forming elements (44, 47, 48) relatively movable on application of forging pressure to the die to converge on a blank therein, a first of the forming elements (44) having in it cavities the shape of which corresponds to the shapes of the teeth to be formed, second and third forming elements (47, 48) having forming faces to form longitudinal guide faces (4, 5) on the Y-form rack portion on the side thereof opposite the teeth (8). The three forming elements (44, 47, 48) are shaped and arranged to move together to converge on the blank to transform it into the final form in such a manner as to inhibit escape of the material of the blank between the first and second or first and third forming elements up to substantially the last instant of closure of the die. It is preferred to provide a fourth forming element (30) between the second and third forming elements which serves to guide their movement and to control the shape of a surface of the rack portion (14) lying between the longitudinal guide faces (4, 5) and it is further preferred to impart to the second (47) and third (48) forming elements a rolling motion as they converge on the blank. The die is preferably constructed to be used in a single direction impact press. A method of making a steering rack bar having a Y-form rack portion and a cylindrical portion from a blank by forging is provided in which an accurately shaped and substantially cylindrical blank is first produced and the cylindrical portion of the blank is held while the Y-form rack portion is formed in a die of the configuration described above.

Loading the Abstract Image...

First Claim