| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a ball screw in which energy required for forging is small. <P>SOLUTION: A columnar steel material 20 is worked by cold forging to obtain a blank 21 having substantially the same shape as a nut 5. Then a part corresponding to a middle part 11b of the inner peripheral surface of a columnar face shape of the blank 21 is recessed to form a recess 24. After forming the recess 24, parts corresponding to both ends 11a, 11a of the inner peripheral surface of the columnar face shape of the blank 21 are recessed by forging using a mold, a part where the recess 24 is recessed further deeper by forging using a mold to form a recessed groove 22 in which a groove depth of the middle part 11b is deeper than the groove depth of both ends 11a, 11a. Further, a screw groove 5a is formed in the inner peripheral surface of the blank 21 by cutting work so as to connect to the ends of the recessed groove 22. Finally, the blank is subjected to heat treatment under a desired condition to obtain the nut 5. <P>COPYRIGHT: (C)2012,JPO&INPIT |
