| 摘要 |
An elongated, rod-like rack (10) for use in an automotive-type steering gear assembly and like mechanisms, is formed of an elongated extruded tube divided lengthwise into a substantially solid rack portion (11) and a substantially hollow, link portion (14). Transversely extending teeth (12) are broached on the rack portion (11) for engagement with a drive pinion means and the like for transmitting power through the rack. The rack is formed by positioning a tubular blank within an open ended extrusion die having an extrusion throat and partially pushing the tubular blank through the throat for extruding the material longitudinally and collapsing radially inwardly to form a substantially solid, elongated rack portion. Then, the extrusion is continued with a punch having a mandrel arranged within the blank and within the die throat for extruding a thin wall length (17), forming the hollow, integral link part (14) of the rack (10). The trailing end may be terminated in an inwardly extending, thick wall portion (18) suitable for forming threads thereon. The elongated rack part (11) has a fine, axially extending opening (15) along its length resulting from a space left when the material is inwardly collapsed in the die throat for providing a communication passageway. <IMAGE> |
