Abstract: A nozzle drive mechanism includes: a plurality of nozzle vanes; a plurality of link plates each fixed to a shaft portion of one of the plurality of nozzle vanes; a nozzle ring having an annular main body portion including shaft holes, each of which pivotally supporting a shaft portion of one of the nozzle vanes, the nozzle ring arranged between the link plates and the nozzle vanes; a regulation pin having one end attached to the main body portion of the nozzle ring and the other end protruding from an opposing surface of one of the link plates facing the nozzle ring; and a positioning pin provided separately from the regulation pin and assembled to a wall portion positioned opposite to the nozzle ring across the link plate at a position where the positioning pin is brought into contact when the nozzle ring rotates.

Abstract: Provided is a turbocharger, including: a turbine impeller(impeller); nozzle vanes provided on a radially outer side of the turbine impeller; a nozzle ring to which the nozzle vanes are provided; a heat-shielding member including: an outer contact portion, which is arranged between a back surface of the turbine impeller and a wall portion of a bearing housing (housing), and is brought into contact with the nozzle ring from a side opposite to the nozzle vanes; and an inner contact portion, which is at a position on an inner side in a radial direction of the shaft with respect to the outer contact portion, and is brought into contact with a wall portion of the bearing housing from the turbine impeller side; and a separation portion, which is formed on the wall portion of the bearing housing, and is recessed toward a side of separating from the heat-shielding member with respect to a contact portion to be brought into contact with the inner contact portion of the heat-shielding member.

Abstract: A turbine shaft includes: a turbine impeller having a protruding portion provided on a back surface of a main body portion thereof and a welded surface provided on the back surface of the main body portion in a radially outer side of the protruding portion; and a shaft having an end hole provided on the one end surface thereof, the end hole in which the protruding portion is inserted, a welding surface provided in a radially outer side of the end hole and welded to the welded surface, a second seal groove provided in another end side with respect to the welding surface, and an enlarged diameter portion formed between the welding surface and the second seal groove, a diameter of the enlarged diameter portion expanding radially outward from the welding surface side toward the second seal groove side.

Abstract: Provided is a nozzle drive mechanism, including: a bearing having a bearing hole; a drive shaft which is axially supported in the bearing hole so as to be rotatable; a drive lever including: an insertion portion into which another end portion (end portion) of the drive shaft protruding from the bearing hole is inserted; and a coupling portion, which is positioned on the bearing side with respect to a center of the drive shaft in an axial direction, and projects outward in a radial direction of the drive shaft from the insertion portion; a link pin coupled to the coupling portion; and a rod member, which is connected to the link pin, is positioned on a side opposite to the bearing with respect to the coupling portion, and is provided to an actuator.

Abstract: In a variable nozzle unit, at a position located away from and opposed to a first nozzle ring in a right-left direction, a second nozzle ring is provided integrally with the first nozzle ring through multiple connecting pins arranged in a circumferential direction. An inner edge portion of a support ring is connected to the first nozzle ring by riveting of one end portions of the multiple connecting pins. Each pin hole in the support ring is formed into such a shape extending in a radial direction of the support ring. A washer is provided between a rim of each pin hole in the support ring and a rivet head brought about by joining of the end portion of the corresponding connecting pin.

Abstract: Provided is a mounting structure, including: an impeller including: a main body portion having a through hole; a plurality of blades provided to an outer peripheral surface of the main body portion; and a boss portion, which is a part of the main body portion, and protrudes toward one end side of the shaft with respect to the plurality of blades; a small-diameter portion, which is a part of the shaft; a first large-diameter portion, which is a part of the shaft, is located on another end side of the shaft with respect to the small-diameter portion; and a small-inner-diameter portion of the through hole, which is formed on a radially inner side of the boss portion, and has an inner diameter smaller than an inner diameter of a part of the through hole which is opposed to the first large-diameter portion in a radial direction.

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 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.

Abstract: A variable geometry turbocharger includes a turbine having a variable nozzle unit, and a compressor. The variable nozzle unit has: a unit main body part that is fixed to a turbine housing and rotatably supports a plurality of nozzle vanes; a drive ring that transmits a driving force to the plurality of nozzle vanes; and a drive ring support member that is fixed to the unit main body part and rotatably supports the drive ring. The drive ring support member is formed by one member and has: base end side parts that regulate movement of the drive ring in a radial direction; tip end side parts that regulate movement of the drive ring to the compressor side; and turbine side receiving parts that regulate movement of the drive ring to the turbine side in the direction of a rotational axis.

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 variable displacement supercharger includes a turbine having: a turbine housing that forms a scroll flow passage disposed around a turbine impeller; a variable nozzle unit that includes a second nozzle ring that faces the scroll flow passage and forms a part of an inner wall of the scroll flow passage; and an annular seal member that seals the gap between the turbine housing and the second nozzle ring. The seal member has a disc spring structure that is inserted into the gap and biases the turbine housing and the second nozzle ring in an axial direction of rotation, and is arranged further inside than the scroll flow passage in the radial direction of the turbine impeller.

Abstract: In a variable nozzle unit, at a position located away from and opposed to a first nozzle ring in a right-left direction, a second nozzle ring is provided integrally with the first nozzle ring through multiple connecting pins arranged in a circumferential direction. An inner edge portion of a support ring is connected to the first nozzle ring by riveting of one end portions of the multiple connecting pins. Each pin hole in the support ring is formed into such a shape extending in a radial direction of the support ring. A washer is provided between a rim of each pin hole in the support ring and a rivet head brought about by joining of the end portion of the corresponding connecting pin.

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.

Abstract: A multistage turbocharging system (1) in which the thickness of at least either one of a valve body (51a) that opens and closes a bypass flow passage opening and a washer (51b) that fixes the valve body (51a) to a mounting portion (52) is greater than the minimum width of a flow passage from a valve assembly (51) to a turbine impeller (2d) of the first turbocharger (2).

Abstract: A multistage turbocharging system (1) in which the thickness of at least either one of a valve body (51a) that opens and closes a bypass flow passage opening and a washer (51b) that fixes the valve body (51a) to a mounting portion (52) is greater than the minimum width of a flow passage from a valve assembly (51) to a turbine impeller (2d) of the first turbocharger (2).

Abstract: A multistage turbocharging system provided with a first turbocharger, a second turbocharger, and an exhaust bypass valve device, in which a seal surface of the opening of the bypass flow passage that is abutted by the bottom surface of the valve body of the exhaust bypass valve device has a higher oxidation resistance than the housing of the second turbocharger.