OIL SEPARATION STRUCTURE

To provide an oil separation structure having a plurality of oil separation parts, for improving the oil recovery efficiency.SOLUTION: The oil separation structure includes a first oil separation part 60 located on the upstream side in the flowing direction of blow-by gas, a second oil separation part 70 located on the further downstream side in the flowing direction than the first oil separation part 60, and a first drain oil path 37 having a first drain port 37a into which oil separated by the first oil separation part 60 flows, the second oil separation part 70 having a second ventilation port 74 where the blow-by gas passes after passing through the first oil separation part 60, and a protruded wall 76 provided around the second ventilation port 74 so as to encircle at least part of the second ventilation port 74 in view from the upstream side in the flowing direction, and protruded from the end face on the first oil collection chamber side to the upstream side in the flowing direction.SELECTED DRAWING: Figure 7 【課題】複数のオイル分離部を有するオイル分離構造において、オイルの回収効率を向上させる。【解決手段】ブローバイガスの流れ方向の上流側に位置する第１オイル分離部６０と、第１オイル分離部６０よりも流れ方向の下流側に位置する第２オイル分離部７０と、第１オイル分離部６０により分離されたオイルが流入する第１ドレン口３７ａを有する第１ドレン油路３７とを備える。第２オイル分離部７０は、第１オイル分離部６０を通過した後のブローバイガスが通る第２通風口７４と、流れ方向の上流側から見て、第２通風口７４を少なくとも部分的に囲むように該第２通風口７４の周囲に設けられ、第１オイル回収室側の端面から流れ方向の上流側に突出する突出壁７６とを有する。【選択図】図７