| 摘要 |
PURPOSE:To prevent effectively the fatigue failure of the 1st and the 2nd fillet parts of a crank shaft by hardening fixed ranges of the shaft including the fillet parts. CONSTITUTION:A pin 6 is eccentrically connected to a journal 4 with an arm 5 in-between, and they are united to one body to form a crank shaft 3. The semicircular range E-A-F7 of the 1st fillet part 1 formed at a joint between the journal 4 and the arm 5 and the semicircular range G-B-H8 of the 2nd fillet part 2 formed at a joint between the arm 5 and the pin 6 are hardened with laser beams, electron beams, arc or the like. Thus, ranges of about 90 deg. before and behind both ends A, B of the shortest straight line connecting the fillet parts 1, 2 in the circumferential direction are hardened, and the fatigue strength of the parts is improved. |
