| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a fatigue strength improvement machining method for a crankshaft capable of improving strength of an end of a pin shaft through-hole by uniformly applying plastic machining on this portion, and a machining device thereof. <P>SOLUTION: A pressing tool 22, wherein one end side is smaller than an inner diameter of a pin shaft through-hole 5 and the other end side is larger than the inner diameter of the pin shaft through-hole 5 and a side face 22a is formed a recessed curved surface from one end side to the other end side and a spherical seat 20a is formed in a central portion of the end face at the other end side, is inserted into the pin shaft through-hole 5 of a crank throw 1 in order to make a side face 22a of the pressing tool 22 come in contact with an end of the pin shaft through-hole 5. Thus, the end of the pin shaft through-hole 5 is plastically deformed by pressurizing the spherical seat 20a by pushing a pressing rod 21a in which a projected section is formed against the spherical seat 20a. Thus, the end of the pin through-hole 5 in which stress concentration tends to occur is strengthened and the fatigue strength of the crank shaft is improved. <P>COPYRIGHT: (C)2011,JPO&INPIT</p> |
