Abstract: A sealing structure of a turbocharger includes a turbine housing including a scroll channel, a nozzle mount, a nozzle plate defining, with the nozzle mount, an exhaust gas channel for introducing an exhaust gas from the scroll channel to a turbine wheel, the nozzle plate including an annular plate portion that has a channel wall surface defining the exhaust gas channel and a tubular portion that extends from an inner peripheral end portion on a back surface of the annular plate portion toward a first inner wall surface of the turbine housing, and a sealing device for sealing a section between the first inner wall surface and an end surface of the tubular portion.

Abstract: A nozzle component according to at least one embodiment of the present disclosure is a nozzle component included in a variable nozzle mechanism of a variable geometry turbocharger. The nozzle component is composed of an iron-based alloy and satisfying the following relational expression: 6.6×A+B?8.0, where A is a total value (mass %) of carbon content and nitrogen content, and B is a total value (mass %) of 0.5 times tungsten content and molybdenum content. The total value B is 1.5 mass % or more.

Abstract: A variable nozzle device includes: a nozzle mount; a plurality of nozzle vanes; a drive ring being having a plurality of receiving portions disposed at different positions along a circumferential direction; and a plurality of lever plates each having a fixed portion to be fixed to corresponding one of the plurality of nozzle vanes and an engaging portion to be engaged with corresponding one of the plurality of receiving portions of the drive ring. The receiving portions include a first-side guide surface and a second-side guide surface. The engaging portions each include a first-side roll surface which is to be in contact with the first-side guide surface and a second-side roll surface which is to be in contact with the second-side guide surface. The first-side roll surface includes a lever-plate-side linear portion extending linearly in at least a part of a range which is to be in contact with the first-side guide surface.

Abstract: A forced induction device (100) includes: a rotor (1) which includes a turbine side shaft portion (11), a compressor side shaft portion (12), and a connection shaft portion (13) connecting these to each other; a turbine side bearing (5) which supports the turbine side shaft portion (11); and a compressor side bearing (6) which supports the compressor side shaft portion (12). A rigidity of the connection shaft portion (13) is lower than that of the turbine side shaft portion (11) and the compressor side shaft portion (12) so that a node in a mode shape at each critical speed involving with an operating rotational speed region of the rotor (1) is located between the turbine side bearing (5) and the compressor side bearing (6).

Abstract: A turbine shaft used for a turbocharger including a turbine and a compressor includes a turbine impeller, and a rotor shaft joined on one end side to the turbine impeller. The rotor shaft includes a fitting region configured to fit with a compressor impeller of the compressor by inserting the other end side of the rotor shaft into a through hole formed in the compressor impeller, a fastening region formed between the fitting region and the other end side of the rotor shaft, and configured to allow fastening by a fastening part, and a tapered part having a maximum outer diameter at a position closest to the turbine impeller in the fitting region and formed such that an outer diameter of the rotor shaft decreases from the position closest to the turbine impeller toward a tip side of the compressor impeller.

Abstract: A variable nozzle device includes: a nozzle mount; a plurality of nozzle vanes; a drive ring being having a plurality of receiving portions disposed at different positions along a circumferential direction; and a plurality of lever plates each having a fixed portion to be fixed to corresponding one of the plurality of nozzle vanes and an engaging portion to be engaged with corresponding one of the plurality of receiving portions of the drive ring. The receiving portions include a first-side guide surface and a second-side guide surface. The engaging portions each include a first-side roll surface which is to be in contact with the first-side guide surface and a second-side roll surface which is to be in contact with the second-side guide surface. The first-side roll surface includes a lever-plate-side linear portion extending linearly in at least a part of a range which is to be in contact with the first-side guide surface.

Abstract: A sealing structure of a turbocharger includes a turbine housing including a scroll channel, a nozzle mount, a nozzle plate defining, with the nozzle mount, an exhaust gas channel for introducing an exhaust gas from the scroll channel to a turbine wheel, the nozzle plate including an annular plate portion that has a channel wall surface defining the exhaust gas channel and a tubular portion that extends from an inner peripheral end portion on a back surface of the annular plate portion toward a first inner wall surface of the turbine housing, and a sealing device for sealing a section between the first inner wall surface and an end surface of the tubular portion.

Abstract: There is provided a turbine wheel includes a plurality of long blades and a plurality of short blades. A trailing edge of each short blade is positioned upstream of a trailing edge of each long blade in an axial direction of the turbine wheel, and at least one of a leading edge of each long blade or a leading edge of each short blade includes an inclined part which is inclined so that a distance to a rotational axis of the turbine wheel decreases toward a hub.

Abstract: Provided is a vibration suppressing method for a supercharger, the supercharger including a shaft, a wheel arranged at one end or the other end of the shaft, and a housing including a wheel cover accommodating the wheel; the method including a determining step of determining a suppression target oscillation frequency to be a suppression target from among oscillation frequencies of the housing vibrating with shaft vibration of the shaft transmitted thereto, a preparing step of preparing a vibration suppressing unit having a natural frequency to be tuned in to the suppression target oscillation frequency, and an attaching step of attaching the vibration suppressing unit prepared in the preparing step onto an outer face of the housing.

Abstract: A turbine shaft used for a turbocharger including a turbine and a compressor includes a turbine impeller, and a rotor shaft joined on one end side to the turbine impeller. The rotor shaft includes a fitting region configured to fit with a compressor impeller of the compressor by inserting the other end side of the rotor shaft into a through hole formed in the compressor impeller, a fastening region formed between the fitting region and the other end side of the rotor shaft, and configured to allow fastening by a fastening part, and a tapered part having a maximum outer diameter at a position closest to the turbine impeller in the fitting region and formed such that an outer diameter of the rotor shaft decreases from the position closest to the turbine impeller toward a tip side of the compressor impeller.

Abstract: A forced induction device (100) includes: a rotor (1) which includes a turbine side shaft portion (11), a compressor side shaft portion (12), and a connection shaft portion (13) connecting these to each other; a turbine side bearing (5) which supports the turbine side shaft portion (11); and a compressor side bearing (6) which supports the compressor side shaft portion (12). A rigidity of the connection shaft portion (13) is lower than that of the turbine side shaft portion (11) and the compressor side shaft portion (12) so that a node in a mode shape at each critical speed involving with an operating rotational speed region of the rotor (1) is located between the turbine side bearing (5) and the compressor side bearing (6).

Abstract: Provided is a vibration suppressing method for a supercharger, the supercharger including a shaft, a wheel arranged at one end or the other end of the shaft, and a housing including a wheel cover accommodating the wheel; the method including a determining step of determining a suppression target oscillation frequency to be a suppression target from among oscillation frequencies of the housing vibrating with shaft vibration of the shaft transmitted thereto, a preparing step of preparing a vibration suppressing unit having a natural frequency to be tuned in to the suppression target oscillation frequency, and an attaching step of attaching the vibration suppressing unit prepared in the preparing step onto an outer face of the housing.

Abstract: A turbomachine includes: a rotational shaft; a pair of thrust collars disposed around the rotational shaft; a thrust bearing disposed around the rotational shaft at an axial directional position between the pair of thrust collars; and an oil-drain channel disposed around the rotational shaft, for draining lubricant oil after lubricating a sliding portion between the thrust bearing and the thrust collars. The oil-drain channel includes: an oil-drain port portion for discharging the lubricant oil inside the oil-drain channel downward; and an oil-guide channel portion disposed above the oil-drain port portion and configured to guide the lubricant oil from the sliding portion in a circumferential direction of the rotational shaft to the oil-drain port portion.

Abstract: An oil-drain device for a thrust bearing includes: a rotor shaft; a collar member mounted to an outer periphery of the rotor shaft; a thrust bearing supporting the rotor shaft in an axial direction; and an oil-drain space forming member defining an oil-drain space through which lubricant oil leaking from a sliding portion of the thrust bearing flows, between the thrust bearing and the oil-drain space forming member. The oil-drain space includes: an oil-drain channel defined between a first end surface of the thrust bearing and a first end surface of the oil-drain space forming member, surrounding the flange portion of the collar member; and an oil-drain port formed below the oil-drain channel, for discharging the lubricant oil flowing through the oil-drain channel outside the oil-drain space.

Abstract: There is provided a turbine wheel includes a plurality of long blades and a plurality of short blades. A trailing edge of each short blade is positioned upstream of a trailing edge of each long blade in an axial direction of the turbine wheel, and at least one of a leading edge of each long blade or a leading edge of each short blade includes an inclined part which is inclined so that a distance to a rotational axis of the turbine wheel decreases toward a hub.

Abstract: An expansion turbine including a turbine housing, a plurality of variable nozzles inside the turbine housing at intervals in a circumferential direction of the expansion turbine, the variable nozzles being configured to be rotatable about a rotation shaft, and a turbine wheel disposed rotatably inside the turbine housing, the turbine wheel including a plurality of turbine blades disposed downstream of the variable nozzles. The turbine housing has a first wall surface which faces tips of the turbine blades, and a second wall surface which faces the first wall surface across a flow path of the working fluid. A blade height of the variable nozzles at an outlet side is greater than a blade height of the turbine blades at an inlet side.

Abstract: To reduce bearing loss due to an oil-shortage region on a pad facing a thrust collar, a thrust bearing according to at least one embodiment of the present invention includes a thrust collar, and at least one bearing pad disposed along a circumferential direction on a bearing surface, the at least one bearing pad having a tapered portion and a land portion. Each of the at least one bearing pad is formed so that a periphery portion on an outer side with respect to a radial direction gets closer to an inner side with respect to the radial direction toward an upstream side with respect to the rotational direction.

Abstract: An oil-drain device for a thrust bearing includes: a rotor shaft; a collar member mounted to an outer periphery of the rotor shaft; a thrust bearing supporting the rotor shaft in an axial direction; and an oil-drain space forming member defining an oil-drain space through which lubricant oil leaking from a sliding portion of the thrust bearing flows, between the thrust bearing and the oil-drain space forming member. The oil-drain space includes: an oil-drain channel defined between a first end surface of the thrust bearing and a first end surface of the oil-drain space forming member, surrounding the flange portion of the collar member; and an oil-drain port formed below the oil-drain channel, for discharging the lubricant oil flowing through the oil-drain channel outside the oil-drain space.

Abstract: A turbomachine includes: a rotational shaft; a pair of thrust collars disposed around the rotational shaft; a thrust bearing disposed around the rotational shaft at an axial directional position between the pair of thrust collars; and an oil-drain channel disposed around the rotational shaft, for draining lubricant oil after lubricating a sliding portion between the thrust bearing and the thrust collars. The oil-drain channel includes: an oil-drain port portion for discharging the lubricant oil inside the oil-drain channel downward; and an oil-guide channel portion disposed above the oil-drain port portion and configured to guide the lubricant oil from the sliding portion in a circumferential direction of the rotational shaft to the oil-drain port portion.

Abstract: An expansion turbine (10A) includes: a turbine housing (13) including a scroll section for taking in working fluid (w); a plurality of variable nozzles (36) disposed inside the turbine housing at intervals in a circumferential direction of the expansion turbine, each of the variable nozzles being configured to be rotatable about a rotation shaft (38); and a turbine wheel (24) disposed rotatably inside the turbine housing, the turbine wheel including a plurality of turbine blades disposed downstream of the variable nozzles. The turbine housing has a first wall surface (50) including a shroud section which faces tips (28a) of the turbine blades, and a second wall surface (52) which faces the first wall surface across a flow path (f) of the working fluid. A blade height of the variable nozzles at an outlet side is greater than a blade height of the turbine blades at an inlet side.