| 摘要 |
In a pipe rack forming method, in a state of holding a pipe forming body by a holding portion in a holding metal mold, at a time of pressing a flat surface portion of the pipe forming body by tooth bottom forming surfaces of respective stages of tooth profile portions in a tooth profile metal mold, the structure is made such as to sequentially employ the tooth profile portions in which a tooth bottom height applied to the flat surface portion is reduced in sequence for the tooth profile portions in the tooth profile metal mold, repeatedly pressing and moving forward and backward mandrels having the same size to an inner periphery of the pipe forming body every time when the respective stages of tooth profile portions in the tooth profile metal mold press the flat surface portion, and forming a rack tooth having a final tooth profile.
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