Multi-link piston internal combustion engine - the lubricating structure of the crank mechanism

摘要

PROBLEM TO BE SOLVED: To provide a structure in which lubricating oil is supplied by injection to a pin boss portion of an upper link from a lower link, capable of securing strength of the pin boss portion and improving in lubrication performance of a pin bearing portion.;SOLUTION: A lower link is provided with a lower link oil passage 22 that passes through a pin boss opposing surface 4c which is opposed to a pin boss portion 5A of an upper link 5 and a bearing surface of a crank pin 3. A crank pin oil passage 21 formed in the crank pin 3 and the lower link oil passage 22 are communicated to each other at a predetermined crank angle so that lubricating oil is supplied by injection to the pin boss portion 5A. At this time, the pin boss portion 5A as a lubricating oil supply object is disposed on a straight line 25 connecting the rotation center 2A of a crank shaft 1 and the end 22A of the lower link oil passage 22 at the side of the pin boss opposing surface. A recess portion 23, which is axially recessed, is provided on the axial side of the pin boss portion 5A.;COPYRIGHT: (C)2014,JPO&INPIT