OIL RETURN STRUCTURE FOR CRANK SHAFT OIL SEAL OF ENGINE

摘要

PROBLEM TO BE SOLVED: To perform smooth return of lubrication oil to an oil pan without flying. ;SOLUTION: A lower case 21 is coupled to the lower end part of a cylinder block and a crank shaft is supported by a bearing part 26. Half-division-form fit-in part 48 are formed in the rear end parts of a cylinder block and the lower case 21 and a cylindrical fitting-in part is formed at the periphery of the crank shaft. Oil seal is pressed in the fitting in part and a gap between the crank shaft and the fitting-in part is sealed therewith. An oil return groove 50 is formed in the coupling surface of the lower case 21 with the cylinder block and the inner side of the fitting-in part 48 is communicated with an oil passage 46 communicated with the interior of an oil pan. Lubrication oil leaking through the bearing part 26 is sealed by an oil seal and returned from the oil return groove 50 to the oil pan through the oil passage 46. Since no lubrication oil splashes on the crank part of the crank shaft, lowering of lubrication performance due to aeration is prevented from occurring by preventing flying of the lubrication oil.;COPYRIGHT: (C)1998,JPO