Rhythm Corporation

Nobuyuki Takehara

Yasuo Morishita

Kazuhisa Shimoda

A method of manufacturing a tie rod bar for a steering linkage of a motor vehicle. Between both end portions of a steel pipe material, through a multistage cold forging, there are formed a spherical section, a neck section, a first shaft section, a second shaft section smaller in diameter than the first shaft section, a hexagonal section, and a third shaft section smaller in diameter than the second shaft section, to thereby constitute the tie rod bar. Secondly, the neck section is formed at a portion of the first shaft corresponding to a proximal end portion of the spherical section, a boot groove is formed at a given position on the second shaft section, close to the spherical section, and a screw section is formed on the third shaft section. Subsequently, a heat treatment is performed to remove the residual stress from the formed components concurrently with increasing the strength and improving the ductility. Finally, a coating is made for rust prevention. The boot groove is made to have an uneven configuration.

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Hamamatsu, Japan

Nobuyuki Takehara