| 摘要 |
PROBLEM TO BE SOLVED: To prevent shortage of oil film by sufficiently supplying lubricating oil to bearing metals of a main bearing which supports a main shaft of a crank shaft of an internal combustion engine, and cooling a sliding surface. SOLUTION: One end of an oil groove 23 formed on an inner surface of a bearing metal 21 on the side of a cylinder block 7 is connected to an oil groove 25 formed on an inner surface of a bearing metal 22 on the side of a bearing cap 13. Since the other end of the oil groove 23 is stopped by an interruption wall 24, the oil grooves 23, 25 join each other to form a C-shaped lubricating oil passage. The other end of the oil groove 25 is opened to the outside through an axial lubricating oil discharging passage 26 having the same depth as the oil groove in a diameter direction. Pressurized lubricating oil is flowed from a main hole 15 to the C-shaped oil grooves 23, 25 through a main journal oil passage 16 and an oil port 17. A large part of the oil flows in one direction along the C-shaped oil groove although a small part of it flows through a clearance 18. The oil is almost discharge to the outside from a discharge passage 26 having small flowing resistance, so that pressure loss in a lubrication circuit is reduced. |
