Bearing assembly for a turbocharger, and a method for manufacturing a bearing assembly for a turbocharger

Patent metadata

Field	Value
Publication number	US-2016252134-A1
Application number	US-201415030693-A
Country	US
Kind code	A1
Filing date	Oct 21, 2014
Priority date	Oct 22, 2013
Publication date	Sep 1, 2016
Grant date	—

Abstract

A bearing assembly for a turbocharger includes a turbine wheel-side ball bearing disposed at one axial end of a tubular body, a compressor impeller-side ball bearing disposed at the other axial end of the tubular body, and a bearing housing. The bearing housing includes an opposed wall opposed to the axially outer side of the outer race of the turbine wheel-side ball bearing, and an opposed wall opposed to the axially outer side of the outer race of the compressor impeller-side ball bearing. The outer race of the turbine wheel-side ball bearing and the outer race of the compressor impeller-side ball bearing have axially outer end surfaces which are axially outwardly displaced from the respective axial end surfaces of the tubular body so that oil films form between the respective outer races and the corresponding opposed walls.

First claim

1 . A bearing assembly for a turbocharger, comprising:
a tubular body through which extends a turbine shaft through which a turbine wheel and a compressor impeller are coupled together; a turbine wheel-side ball bearing comprising an outer race fitted to one of two axial end portions of the tubular body ( 5 ), an inner race provided inside of the outer race and fitted to an outer periphery of the turbine shaft, and a plurality of balls disposed between the outer race and the inner race; a compressor impeller-side ball bearing comprising an outer race fitted to the other of the two axial end portions of the tubular body, an inner race provided inside of the outer race of the compressor impeller-side ball bearing and fitted to the outer periphery of the turbine shaft, and a plurality of balls disposed between the outer race and the inner race, of the compressor impeller-side ball bearing; an outer race spacer disposed between the outer race of the turbine wheel-side ball bearing and the outer race of the compressor impeller-side ball bearing, and keeping the outer race of the turbine wheel-side ball bearing and the outer race of the compressor impeller-side ball bearing axially spaced apart from each other; and a bearing housing in which is mounted the tubular body such that an oil film capable of radially supporting the tubular body forms along an outer periphery of the tubular body, wherein the bearing housing includes a turbine wheel-side opposed wall opposed to an axially outer side of the outer race of the turbine wheel-side ball bearing, and a compressor impeller-side opposed wall opposed to an axially outer side of the compressor impeller-side ball bearing, and wherein the tubular body has two axial end surfaces, and the outer race of the turbine wheel-side ball bearing and the outer race of the compressor impeller-side ball bearing each have an axial end surface located at a same axial position as, or at a position axially outwardly displaced from, a corresponding one of the two axial end surfaces of the tubular body, such that oil films capable of axially supporting the outer races form between the respective outer races and the corresponding opposed walls.

2 . The bearing assembly for a turbocharger of claim 1 , wherein the outer race spacer is integral with the tubular body.

3 . The bearing assembly for a turbocharger of claim 1 , wherein the inner race of the turbine wheel-side ball bearing and the inner race of the compressor impeller-side ball bearing each have an inner race extensions extending axially inwardly such that axially inner end surfaces of the respective inner races contact each other.

4 . A method of manufacturing the bearing assembly for a turbocharger of claim 2 , comprising:
manufacturing outer race members each of which can constitute the outer race of the turbine wheel-side ball bearing, and outer race members each of which can constitute the outer race of the compressor impeller-side ball bearings; classifying the outer race members into a plurality of groups according to axial width dimensions of the outer race members; manufacturing tubular body members each of which can constitute the tubular body, and is integral with the outer race spacer; classifying step of classifying the tubular body members into a plurality of groups according to axial width dimensions of the corresponding outer race spacer members; and matching the groups classified during the classifying of the outer race members with the groups classified during the classifying of the tubular body members, and assembling together outer race members of one of the groups classified during the classifying of the outer race members, and a tubular body member of one of the groups classified during the classifying of the tubular body members that is matched with said one of the groups classified during the classifying of the outer race members, into the bearing assembly.

5 . The bearing assembly for a turbocharger of claim 2 , wherein the inner race of the turbine wheel-side ball bearing and the inner race of the compressor impeller-side ball bearing each have an inner race extensions extending axially inwardly such that axially inner end surfaces of the respective inner races contact each other.

Assignees

• Ntn Toyo Bearing Co Ltd

Inventors

• Koda Tsuyoshi
• Nakao Goro

Classifications

• F16C33/586

  outside the space between the races, e.g. end faces or bore of inner ring · CPC title

• F01D25/16

  Arrangement of bearings; Supporting or mounting bearings in casings (bearings per se F16C) · CPC title

• F16C19/548

  in O-arrangement · CPC title

• F16C33/6659

  Details of supply of the liquid to the bearing, e.g. passages or nozzles · CPC title

• F16C35/12

  with ball or roller bearings {(adjustable bearings F16C23/00, F16C25/00; elastic bearings F16C27/00)} · CPC title