| 摘要 |
PROBLEM TO BE SOLVED: To provide a rocker arm and a rocker shaft each having an extended service life by suppressing wear and pitching. SOLUTION: The rocker arm 81 for opening/closing a valve 54, and the rocker shaft 86 for supporting the rocker arm 81, are provided with innumerable micro recesses randomly at a contact part of the rocker arm 81 with the rocker shaft 86 and a contact part of the rocker shaft 86 with the rocker arm 81. A surface roughness parameter Ryni of a surface provided with the recesses is within a range of 0.4μm≤Ryni≤1.0μm, and an Sk value is -1.6 or less. A contact surface thereby obtains high oil film forming ability, and a long service life can be obtained even under the condition that oil film thickness is extremely thin under low viscosity and lean lubrication. COPYRIGHT: (C)2007,JPO&INPIT
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