Abstract: A bearing structure includes: a housing; a bearing hole, which is formed in the housing, and receives a bearing configured to axially support a shaft having one end provided with an impeller; a clearance groove, which is formed in an inner circumferential surface of the bearing hole, and communicates with a passage formed on a lower side of the shaft; and an inclined portion formed on an inner wall surface of the clearance groove, which is positioned at least above the shaft.

Abstract: A bearing structure includes: a housing; a bearing hole formed in the housing and provided with a bearing for pivotally supporting a shaft; a clearance groove provided in the bearing hole, having an opposing wall portion radially opposed to the shaft, and communicating with an oil drainage passage provided below a shaft center of the shaft; and at least one of a narrow portion or a wide portion in the opposing wall portion of the clearance groove with a boundary right above the shaft center of the shaft, the narrow portion provided in a rear side in a rotation direction of the shaft, the narrow portion having a narrower gap from the shaft than that in a front side in the rotation direction of the shaft, the wide portion provided in the front side in the rotation direction of the shaft, the wide portion having a wider gap from the shaft than that in the rear side in the rotation direction of the shaft.

Abstract: A bearing structure includes: a housing; a bearing hole formed in the housing; a bearing, which is provided in the bearing hole, and is configured to axially support a shaft having one end provided with a turbine impeller; a space, which is formed in the housing, and is positioned between the impeller and the bearing hole; a passage, which communicates with the space, and extends to a vertically lower side of the bearing hole; a communication opening portion, which allows the passage and the bearing hole to communicate with each other; and a lower wall portion, which is provided in a lower portion including a portion directly below an axis of the shaft between the passage and the bearing hole, and has an inner wall surface being opposed to the shaft and having a curved surface shape with a curvature center positioned on the shaft side.