| 摘要 |
PROBLEM TO BE SOLVED: To provide a crank pin bolt enabling measuring/managing by a ultrasound axial force meter while preventing galling of a screw portion tip end and ensuring an effect of reducing a stress. SOLUTION: In the crank bolt 21 fastening a divided large end portion of a connecting rod to a crank pin, a recessed portion 37 is formed on a tip end surface 35, and a flat bottom portion 41 in a direction orthgonal to an axis line 39 is provided on the recessed portion 37. The crank pin bolt may make an inner surface of the recessed portion to be a taper surface gradually decreased in a diameter toward the bottom portion. In this case, preferably, the recessed portion is 20 to 60 % of a bolt outer diameter in diameter of the bottom portion, and 20 to 120°in taper angle. COPYRIGHT: (C)2004,JPO
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