| 摘要 |
PROBLEM TO BE SOLVED: To provide a rack for a steering device which is light in weight, and is improved in the rigidity of whole rack teeth by improving a filling-up degree of a base material into a tooth shape, and to provide a method for manufacturing the rack. SOLUTION: The inner diameter hole 12 of a first rack base material 1 bites into the upper surface 21 of a second rack base material 2 by pushing a punch 41 downward, and the base material is allowed to flow upwards with the reaction force to be used for molding the rack tooth 13, so that the filling-up degree into the tooth shape is improved. Further, at the time of finishing the tooth shape, a gap 52 remains between the side orthogonal to the rack tooth formation side in the inner diameter hole 12 of the first rack base material 1 and the outer periphery 22 of the second rack base material 2, so that a mold is prevented from becoming in a closed state, then the molding load can be reduced to extend the service life of the mold. Also, the upper surface 21 of the second rack base material 2 bites into the inner diameter hole 12 of the first rack base material 1 to integrate the first rack base material 1 and the second rack base material 2 with each other, so that the rigidity of the whole formed rack teeth is improved. COPYRIGHT: (C)2007,JPO&INPIT
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