| 摘要 |
PURPOSE:To enable to manufacture a rack superior in its tensile strength, wear resistance and other properties with high accuracy and at a low cost, by fitting a rack tooth section made of a sintered metal in a groove part formed in the rack shaft in the manner that the rack tooth section and the rack shaft are integral with each other. CONSTITUTION:Since a rack tooth section 26 made of metal powder 24 is fitted tightly in a stepped part 23b and a recess 23d formed between a flat part 23a and a groove part 23c of a rack shaft member 23, the rack tooth section 26 and the rack shaft section 23 are coupled tightly together. Further, since the rack tooth section 26 is subjected to sintering process, it has a sufficiently high toughness and strength. Here, if the tooth form of rack teeth 26a is rather complicated, they can be finished accurately. By subjecting the rack tooth section 26 to oil impregnating process or the like, it is enabled to obtain a rack superior also in wear resistance. |
