Abstract: A bearing structure includes a radial bearing surface for rotatably supporting a shaft; and a radial groove including a front wall surface portion and extending to one end of a radial bearing surface, the front wall surface portion being formed between a rear continuous portion and a front continuous portion positioned on the radial bearing surface, and extending from the front continuous portion along an imaginary line or extending forward from the front continuous portion relative to the imaginary line in the rotation direction, the imaginary line intersecting a tangent of the radial bearing surface at the front continuous portion at degrees and extending from the front continuous portion in a direction separated from the shaft and backward in the rotation direction, in a cross-section orthogonal to an axial direction of the shaft.

Abstract: Provided is a bearing structure, including: a thrust bearing surface having a through hole for allowing a shaft to be inserted therethrough; a plurality of land portions, which are formed on the thrust bearing surface, and are separated apart from each other in a rotation direction of the shaft; a tapered portion, which is formed between the plurality of land portions on the thrust bearing surface, and has a projection height in an insertion direction of the shaft which becomes higher toward a forward side in the rotation direction; and a thrust groove, which is formed in the tapered portion, and extends from the through hole to a radially inner side of an outer peripheral end of the tapered portion.

Abstract: A bearing structure S includes: a bearing hole formed in a housing; a main body portion of a bearing provided in the bearing hole and inserted with a shaft therethrough; damper surface and provided on an outer circumferential surface of the main body portion, the damper surface facing an inner circumferential surface of the bearing hole; thrust surface provided at end portions of the main body portion in an axial direction of the shaft; and thrust back surface portions provided in the main body portion and having an outer diameter larger than those of the damper surface, the thrust back surface portions spaced apart from the damper surface by a distance farther than a distance between each of the damper surface and the inner circumferential surface of the bearing hole and positioned on back sides of the thrust surface.

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 through-hole penetrating through in the axial direction of shaft, a bearing holder accommodated in the through-hole, a semi-floating metal bearing accommodated in the bearing holder and supporting the shaft inserted into the inside, and a positioning member being inserted into a radial direction of the shaft for both the bearing holder and the semi-floating metal bearing and regulating movement of the semi-floating metal bearing in the axial direction and in a rotating direction of the shaft relative to the bearing holder. For the bearing holder, a press-fit portion to be press-fitted into the through-hole is formed. A gap is formed between at least one of outer circumferential surfaces of both end parts of the bearing holder in the axial direction and the inner circumferential surface of the through-hole.

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.

Abstract: A turbocharger includes: a shaft provided with a small-diameter portion, and two large-diameter portions formed on two sides of the small-diameter portion; and a semi-floating bearing to rotatably support the shaft. The semi-floating bearing includes a cylindrical body into which the shaft is inserted. An inner peripheral surface of the body includes: two bearing surfaces opposed to the large-diameter portions of the shaft; a non-bearing surface located between the two bearing surfaces, having a larger inner diameter than inner diameters of the bearing surfaces; and an oil passage opened to the non-bearing surface to supply lubricant oil to a gap in a radial direction between the non-bearing surface and the shaft. At least one of the two bearing surfaces extends more in an approaching direction of the two bearing surfaces than does the large-diameter portion opposed in the radial direction to the one bearing surface.

Abstract: Provided is a bearing structure, including: a thrust bearing surface having a through hole for allowing a shaft to be inserted therethrough; a plurality of land portions, which are formed on the thrust bearing surface, and are separated apart from each other in a rotation direction of the shaft; a tapered portion, which is formed between the plurality of land portions on the thrust bearing surface, and has a projection height in an insertion direction of the shaft which becomes higher toward a forward side in the rotation direction; and a thrust groove, which is formed in the tapered portion, and extends from the through hole to a radially inner side of an outer peripheral end of the tapered portion.

Abstract: A bearing structure includes a radial bearing surface for rotatably supporting a shaft; and a radial groove including a front wall surface portion and extending to one end of a radial bearing surface, the front wall surface portion being formed between a rear continuous portion and a front continuous portion positioned on the radial bearing surface, and extending from the front continuous portion along an imaginary line or extending forward from the front continuous portion relative to the imaginary line in the rotation direction, the imaginary line intersecting a tangent of the radial bearing surface at the front continuous portion at degrees and extending from the front continuous portion in a direction separated from the shaft and backward in the rotation direction, in a cross-section orthogonal to an axial direction of the shaft.

Abstract: A turbocharger includes: a housing; a bearing member provided in the housing and having bearing surface; and a shaft having received surface facing the bearing surface, respectively, in a direction of a rotational axis and a large diameter portion extending from an outer periphery of the received surface and formed with a separation portion spaced apart from the bearing surface more than the received surface is.

Abstract: A bearing structure includes: a bearing hole formed in a bearing housing, a semi-floating metal bearing accommodated in the bearing hole and having a pin hole formed therein; a through-hole formed in the bearing housing and facing the pin hole in the semi-floating metal bearing; a regulating member which is inserted into the through-hole and in which a fixed portion is pressed onto an inner surface of the through-hole for the regulating member to be fixed to the bearing housing at a fixed position where a distal end portion is inserted into the pin hole; a regulating hole opened at a base end in the insertion direction of the regulating member and extending at least to the fixed portion toward the distal end side; and a pressing member provided in the regulating hole to expand the regulating hole by pressing an inner surface of the regulating hole.

Abstract: A bearing structure S includes: a bearing hole formed in a housing; a main body portion of a bearing provided in the bearing hole and inserted with a shaft therethrough; damper surface and provided on an outer circumferential surface of the main body portion, the damper surface facing an inner circumferential surface of the bearing hole; thrust surface provided at end portions of the main body portion in an axial direction of the shaft; and thrust back surface portions provided in the main body portion and having an outer diameter larger than those of the damper surface, the thrust back surface portions spaced apart from the damper surface by a distance farther than a distance between each of the damper surface and the inner circumferential surface of the bearing hole and positioned on back sides of the thrust surface.

Abstract: A bearing structure includes: an outer circumferential groove formed on an outer circumferential surface of a cylindrical portion of a semi-floating metal bearing, and including two opposed surfaces opposed to each other in an axial direction of a shaft and a bottom surface connected to the two opposed surfaces; a radial hole penetrating a wall portion defining the bearing hole so as to communicate with the bearing hole, and facing the outer circumferential groove of the semi-floating metal bearing; a locking member having a body inserted into the radial hole from the outer side of the shaft, wherein at least part of the body is interposed between the two opposed surfaces and fixed to the outer circumferential groove; and an opposed portion provided in the housing, and opposed to the part of the body of the locking member when the locking member is fixed to the outer circumferential groove.

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, 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; 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.

Abstract: A bearing structure includes: a bearing hole formed in a bearing housing, a semi-floating metal bearing accommodated in the bearing hole and having a pin hole formed therein; a through-hole formed in the bearing housing and facing the pin hole in the semi-floating metal bearing; a regulating member which is inserted into the through-hole and in which a fixed portion is pressed onto an inner surface of the through-hole for the regulating member to be fixed to the bearing housing at a fixed position where a distal end portion is inserted into the pin hole; a regulating hole opened at a base end in the insertion direction of the regulating member and extending at least to the fixed portion toward the distal end side; and a pressing member provided in the regulating hole to expand the regulating hole by pressing an inner surface of the regulating hole.

Abstract: A bearing structure includes a through-hole penetrating through in the axial direction of shaft, a bearing holder accommodated in the through-hole, a semi-floating metal bearing accommodated in the bearing holder and supporting the shaft inserted into the inside, and a positioning member being inserted into a radial direction of the shaft for both the bearing holder and the semi-floating metal bearing and regulating movement of the semi-floating metal bearing in the axial direction and in a rotating direction of the shaft relative to the bearing holder. For the bearing holder, a press-fit portion to be press-fitted into the through-hole is formed. A gap is formed between at least one of outer circumferential surfaces of both end parts of the bearing holder in the axial direction and the inner circumferential surface of the through-hole.

Abstract: A bearing structure includes a bearing holder that has a hollow main body and an oil hole penetrating through from an outer circumferential surface to an inner circumferential surface of the main body to thereby guide a lubricating oil to the inside of the main body, and that is fixed in a bearing housing; two full-floating metal bearings that are arranged separated from each other in the axial direction of the shaft and support the shaft, in the bearing holder; two thrust bearing surfaces each arranged on the outside of two full-floating metal bearings in the axial direction of the shaft; and two collars each arranged on the outside of two thrust bearing surfaces in the axial direction of the shaft and provided for the shaft. The lubricating oil lubricates thrust bearing surfaces after lubricating full-floating metal bearings.