Patent ID: 8256404

Claim:
An oil separator for trapping oil mist contained in blow-by gas generated inside a crankcase of an engine, comprising: multiple cones arranged in a line; and a rectification chamber containing the cones for the blow-by gas, the rectification chamber extending in parallel to the line of cones and arranged on an upper side of the cones, said rectification chamber including a flow-in port for the blow-by gas, the flow-in port positioned at one end of the line of cones to force blow-by gas in a direction from said one end of the line of cones and into each of the cones, wherein: each cone includes an upper outer peripheral wall that includes a partition wall and a common wall, said partition wall faces said rectification chamber and partitions the rectification chamber from the cone, and the common wall comprises a wall that is common to an adjacent cone; the partition wall of each cone defines a slit allowing the blow-by gas to flow into the cone, said slit extending in a direction that is parallel to an axial direction of each such cone; and wherein blow-by gas from the flow-in port enters the rectification chamber, flows inside the rectification chamber along an outer peripheral wall of the rectification chamber or along the partition walls of the cones, and flows through each slit into each cone; wherein a first cone is positioned nearer to the flow-in port than all other cones, the slit of the first cone includes a height approximately the same as a height of the first cone's partition wall, the slit of the first cone opens toward the flow-in port, and a portion of the partition wall that comprises a side surface of the slit is formed in parallel to an opening direction of the slit; and the slit of each cone other than the first cone extends between each such cone's partition wall and the common wall of each such cone and a cone positioned nearer to the flow-in port, wherein the slit of each such other cone includes a height approximately the same as a height of the each such cone's partition wall; and wherein said partition walls and said common walls are continuous with each other.