| 摘要 |
PURPOSE:To reduce a pump load by feeding lube oil optimum for the extent of a load working on journals in such a way that low pressure lube oil is supplied to journal bearings at both extreme sides and high pressure oil to the journal bearings at an intermediate position. CONSTITUTION:A cam shaft 12 is provided with journals J1-J5 supported on a cylinder head 3, and each journal bearing is fed with oil from an oil pump 31 via an oil feed passage 32. The oil feed passage 32 is branched into a primary distribution passage 30 of high pressure via an orifice of large diameter, and a low pressure lubricating passage 35 via an orifice of small diameter, respectively. Among said journals, bearings for J1 and J2 located at both extreme sides are supplied with lube oil from the low pressure lubricating passage 35, while bearings for J3 and J5 at an intermediate position are supplied with oil from the high pressure primary distribution passage 30.
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