| 摘要 |
PURPOSE:To reduce the weight of a rack shaft by forming a rack on the portion which is press molded from a steel pipe. CONSTITUTION:A rack shaft 2 is formed with a hollow rack shaft made of a thin steel pipe with a coaxial circular hole, and only the rack forming position is formed by press molding at a recessed section in parallel to the axis of the steel pipe and with a flat and rectangular bottom, then the rack 2C is formed on the bottom 2D of this recessed section. Thereby, a singular shape hole 2A is given to the rack 2C portion of the rack shaft 2, and a circular hole 2B is left to the other portion. The thickness of the shaft except for the position where the rack 2C is formed is kept equal to the original thickness of the steel pipe. Therefore, the cross section of the shaft can be made uniform, thus the stress distribution is kept uniform and the weight of the shaft can be reduced. |
