Abstract: A turbocharger includes: a shaft; a rolling bearing including an inner ring mounted on the shaft and an outer ring arranged around the inner ring; a housing including a bearing hole accommodating the rolling bearing; a compressor impeller provided on the shaft at an outside the bearing hole; and an annular bearing retainer plate arranged between the bearing hole and the compressor impeller in the central axis direction of the shaft and including an end face facing a side face of the outer ring, the end face including an annular circumferential oil groove continuously extending along the entire circumferential direction of the shaft and a protrusion located inside the circumferential oil groove in a radial direction of the shaft and protruding in a central axis direction of the shaft.

Abstract: A bearing structure includes: a shaft provided with a turbine impeller; a pair of rolling bearings accommodated in a bearing hole and each including: an inner ring provided to the shaft; and an outer ring having a damper portion formed on an outer periphery of the outer ring; an opposing surface opposed to, from a turbine impeller side, a lateral surface of the outer ring of the rolling bearing provided on the turbine impeller side; and a first oil supply groove formed in the opposing surface and opposed to at least the damper portion and the lateral surface of the outer ring.

Abstract: A turbocharger includes ball bearings each including an inner ring and an inner ring mounted to a shaft, and an outer ring and an outer ring provided so as to be relatively rotatable in a bearing hole, and damper portions formed in at least one of outer peripheral surfaces of the outer ring and the outer ring and opposed surfaces of inner peripheral surface of the bearing hole opposed to the outer peripheral surfaces of the outer ring and the outer ring.

Abstract: Provided is a bearing structure, including: a damper groove formed in at least one of an outer peripheral surface of an outer ring of a rolling bearing or an inner peripheral surface of a bearing hole so as to extend in a circumferential direction of a shaft; and a second oil drain hole having one end communicating with the damper groove, and another end opened to an outside of a cylindrical portion.

Abstract: A bearing structure includes: a shaft provided with a turbine impeller; a pair of rolling bearings accommodated in a bearing hole and each including: an inner ring provided to the shaft; and an outer ring having a damper portion formed on an outer periphery of the outer ring; an opposing surface opposed to, from a turbine impeller side, a lateral surface of the outer ring of the rolling bearing provided on the turbine impeller side; and a first oil supply groove formed in the opposing surface and opposed to at least the damper portion and the lateral surface of the outer ring.

Abstract: Provided is a bearing structure, including: a damper groove formed in at least one of an outer peripheral surface of an outer ring of a rolling bearing or an inner peripheral surface of a bearing hole so as to extend in a circumferential direction of a shaft; and a second oil drain hole having one end communicating with the damper groove, and another end opened to an outside of a cylindrical portion.

Abstract: Provided is a bearing structure including: a shaft; a first opposed surface, which is formed on the shaft or a member mounted to the shaft; a first bearing portion, which is opposed to the first opposed surface from one end side of the shaft; a second opposed surface, which is formed on the shaft or the member mounted to the shaft, and is positioned on the one end side of the shaft with respect to the first opposed surface and the first bearing portion; and a second bearing portion, which is opposed to the second opposed surface from the one end side of the shaft.

Abstract: A turbocharger includes ball bearings each including an inner ring and an inner ring mounted to a shaft, and an outer ring and an outer ring provided so as to be relatively rotatable in a bearing hole, and damper portions formed in at least one of outer peripheral surfaces of the outer ring and the outer ring and opposed surfaces of inner peripheral surface of the bearing hole opposed to the outer peripheral surfaces of the outer ring and the outer ring.

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: Provided is a bearing structure including: a shaft; a first opposed surface, which is formed on the shaft or a member mounted to the shaft; a first bearing portion, which is opposed to the first opposed surface from one end side of the shaft; a second opposed surface, which is formed on the shaft or the member mounted to the shaft, and is positioned on the one end side of the shaft with respect to the first opposed surface and the first bearing portion; and a second bearing portion, which is opposed to the second opposed surface from the one end side of the shaft.

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: 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; 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 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.