| 摘要 |
<P>PROBLEM TO BE SOLVED: To manufacture a hollow rack bar without reducing productivity, while securing sufficiently the tooth width and tooth height for a tooth part. <P>SOLUTION: A device includes: a die 20 that has a tooth mold 24 and holds a steel tube 1A opened at both ends and having a processing wall 5 on which racks 4 are formed by the tooth mold 24; a core metal M that is press-fit into the steel tube 1A, thereby causing plastic flow of the processing wall 5 coming into contact with the tooth mold 24 from the inside to the outside of the steel tube 1A to form the racks 4 corresponding to the tooth mold 24; a core metal driving mechanism 40 for press-fitting the core metal M into the inside of the steel tube 1A held by the die 20; and an ultrasonic generation part 60 for providing ultrasonic vibration to the tooth mold 24. <P>COPYRIGHT: (C)2013,JPO&INPIT |
