LUBRICATION STRUCTURE AND LUBRICATION METHOD FOR UPPER PIN IN PISTON CRANK MECHANISM OF INTERNAL COMBUSTION ENGINE

摘要

This lubrication mechanism is applied to a double link type piston crank mechanism having an upper link (3), a lower link (6), and a control link (7). Lubricating oil is supplied through an oil supply hole (19) to an oil reservoir (21) formed by a plate-shaped member (22) between a pair of pin bosses for an upper pin. The lubricating oil inside the oil reservoir (21) is supplied to the upper pin (4) by reciprocating rotary motion of an upper link-side pin boss section (25) provided with an oil groove (29) on an end surface.