Patent ID: 8701621
Filing Date: 2014-04-22
Classification: F01M

Abstract:
1. A four-cycle engine comprising: a cylinder block which includes a cylinder bore retaining a piston moving back and forth; a crankcase which is attached to the cylinder block and which rotatably supports a crankshaft; a partition wall which partitions an interior of the crankcase into a crank room retaining the crankshaft and an oil room retaining an oil that lubricates the crankshaft; a communication path which communicates the crank room with the oil room and which guides oil in the crank room to the oil room; and an oil supply unit which supplies the oil in the oil room into the crank room, wherein a cross section of the partition wall is formed in a substantially V shape with an apex being located downward, given that a direction in which the piston goes from a bottom dead center toward a top dead center is upward as crankshaft is viewed in an axial direction downwardly, and the communication path is formed at the apex, the communication path is located leftward of a plane which passes through an axial line of the crankshaft and includes an axial line of the cylinder bore as the crankshaft is viewed in a clockwise direction, the partition wall comprises a first partition wall and a second partition wall which are spaced apart from each other at the apex, the communication path is defined by the first partition wall and the second partition wall, the second partition wall extends in the vertical direction, wherein an end of the first partition wall at the apex side is located leftward of an end of the second partition wall, or in the same plane of the second partition wall, at the apex side as the crankshaft is viewed in a clockwise direction, and wherein the oil room is defined by the partition wall and an external wall of the crankcase.