| 摘要 |
This invention aims to provide a steering rack bar in low costs, which is hollowed in overall length, and for use in steering equipment for automobiles. A rack (2) is formed on a first steel tube (11) by plastic working, wherein the first steel tube has good plastic workability by low carbon content, and has high strength after hardening. The above first steel tube (3) and a second steel tube (4) are joined to complete a hollow steering rack bar, wherein the second steel tube has a higher carbon content and is lower cost than the first steel tube. Moreover, the second steel tube which has a margin of the strength can be thinner than the first steel tube for reduction of weight. <IMAGE> |
