Turbocharger and method

• US 9,683,520 B2
• Filed: 03/09/2015
• Issued: 06/20/2017
• Est. Priority Date: 03/09/2015
• Status: Expired due to Fees

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Powers, Gary W., Williams, Gregg, Williams, Thomas J., Annati, Richard E., McCormack, Jeffrey W.
• Primary Examiner(s): Trieu, Thai Ba
• Application Number:
  US14/641,665
• Publication Number:
  US 20160281645A1
• Time in Patent Office: 834 Days
• Field of Search: 606051, 606052, 606053, 417406-407, 384 99, 384475, 384535, 384585, 384906, 184 611
• CPC Class Codes: F01D 25/16 Arrangement of bearings; Supporting or mounting bearings in casings bearings per se F16C
• CPC Class Codes: F01D 25/183 Sealing means
• CPC Class Codes: F01D 25/24 Casings modified for heating or cooling F01D25/14; Casing parts, e.g. diaphragms, casing fastenings casings for rotary machines or engines in general F16M ; special arrangements in stators dealing with breaking-off of part of rotor F01D21/045
• CPC Class Codes: F02B 37/00 Engines characterised by provision of pumps driven at least for part of the time by exhaust
• CPC Class Codes: F02B 39/14 Lubrication of pumps; Safety measures therefor
• CPC Class Codes: F02M 26/04 with a single turbocharger
• CPC Class Codes: F02M 26/05 High pressure loops, i.e. wherein recirculated exhaust gas is taken out from the exhaust system upstream of the turbine and reintroduced into the intake system downstream of the compressor
• CPC Class Codes: F04D 25/024 the driving means being assisted by a power recovery turbine
• CPC Class Codes: F04D 29/059 Roller bearings
• CPC Class Codes: F05D 2220/40 in turbochargers
• CPC Class Codes: F16C 19/184 in O-arrangement
• CPC Class Codes: F16C 2360/24 Turbochargers in general F02C6/12
• CPC Class Codes: F16C 27/045 with a fluid film, e.g. squeeze film damping
• CPC Class Codes: F16C 33/767 integral with the race
• CPC Class Codes: F16C 35/063 Fixing them on the shaft with interposition of an element F16C35/07
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies

Abstract

A turbocharger includes a turbine, a compressor, and a bearing housing forming a bearing bore. A bearing arrangement is disposed between a shaft interconnecting the turbine and compressor wheels, and the bearing housing. The bearing arrangement includes first and second bearings formed between an outer bearing race element disposed within the bearing bore an inner bearing race element disposed within the outer bearing race element and between the outer bearing race element and the shaft. The inner bearing race element rotates with the shaft and forms an extension segment having an open channel that, together with an annular surface on an inner side of a back of the compressor wheel, forms a U-shaped channel into which a ring seal is disposed. The ring seal sealably engages the inner bearing race element and also slidably and sealably engages the inner bore of the bearing retainer.

Claims

1. A turbocharger, comprising:

a turbine that includes a turbine wheel;

a compressor that includes a compressor wheel;

a bearing housing disposed and connected between the turbine and the compressor, the bearing housing forming a bearing bore therethrough;

a shaft rotatably disposed within the bearing housing and extending into the turbine and the compressor, wherein the turbine wheel is connected to one end of the shaft and wherein the compressor wheel is connected to an opposite end of the shaft such that the turbine wheel is rotatably disposed in the turbine and the compressor wheel is rotatably disposed in the compressor;

first and second bearings disposed between the shaft and the bearing housing, first and second rollers formed between an outer race disposed in the bearing bore, and an inner race disposed in the outer race;

a bearing retainer connected between the bearing housing and the compressor, the bearing retainer forming an inner bore through which the shaft extends,

wherein the inner race is arranged to rotate with the shaft, and

wherein the inner race forms an extension segment extending up to the compressor wheel, the extension segment forming an open channel that, together with an annular surface on an inner side of a back of the compressor wheel that faces the shaft, forms a U-shaped channel; and

a ring seal disposed in the U-shaped channel, the ring seal sealably engaging the inner race and also slidably and sealably engaging the inner bore of the bearing retainer,

wherein an end face of the inner race forms a radially outward extending portion that slopes away from the shaft to centrifuge oil away from the ring seal and towards the first and second bearings, and

wherein a tortuous path is provided between an oil collection gallery of the bearing housing and the ring seal.

2. The turbocharger of claim 1, wherein the ring seal is made of a hardened material.

3. The turbocharger of claim 1, wherein the ring seal has a rectangular cross section.

4. The turbocharger of claim 1, wherein the tortuous path is defined along an interface between the bearing retainer and the inner race to discourage oil flow towards the ring seal.

5. The turbocharger of claim 4, wherein the bearing retainer forms an inwardly facing cylindrical wall around the inner bore, and wherein the tortuous path is defined between the inwardly facing cylindrical wall and the radially outward extending portion, which are axially aligned.

6. The turbocharger of claim 1, wherein the inner race forms a flared portion having an increased inner diameter with respect to end portions thereof that engage the shaft.

7. The turbocharger of claim 6, wherein the shaft is connected to the inner race at end portions, the end portions having a first diameter, the shaft further forming a slender portion between the end portions, the slender portion having a second diameter that is less than the first diameter.

8. The turbocharger of claim 7, wherein the increased inner diameter of the inner race overlaps in an axial direction with the slender portion of the shaft.

9. The turbocharger of claim 1, wherein the inner race is formed by two components, a compressor-side cup and a turbine-side cup.

10. A method for rotatably and sealably supporting a shaft within a bearing housing of a turbocharger, comprising:

connecting a turbine wheel at one end of the shaft;

forming a first roller bearing by engaging a first plurality of rollers with a first inner race groove formed in an inner race and with a first outer race groove formed in an outer race;

forming a second roller bearing by engaging a second plurality of rollers with a second inner race groove formed in the inner race and with a second outer race groove formed in the outer race;

engaging the outer race between a bearing bore formed in the bearing housing and the shaft, which extends through the bearing bore, such that the inner race rotates with the shaft with respect to the outer race;

axially mounting the inner and outer races in the bearing bore formed in the bearing housing around the shaft, and axially constricting the outer race in the bearing bore with a bearing retainer having an inner bore through which the shaft extends;

installing a compressor wheel on a free end of the shaft opposite the turbine wheel,

wherein the inner race forms an extension segment extending up to the compressor wheel, the extension segment forming an open channel that, together with an annular surface on an inner side of a back of the compressor wheel that faces the shaft, forms a U-shaped channel;

creating a sliding seal between the inner race and the inner bore of the bearing retainer by placing a ring seal in the U-shaped channel, the ring seal sealably engaging the inner race and also slidably and sealably engaging the inner bore of the bearing retainer,

wherein an end face of the inner race forms a radially outward extending portion that slopes away from the shaft to centrifuge oil away from the ring seal and towards the first and second bearings; and

creating a tortuous path between an oil collection galley of the bearing housing and the ring seal to discourage transfer of oil from the oil collection galley towards the ring seal.

11. The method of claim 10, wherein the ring seal is made of a hardened material.

12. The method of claim 10, wherein the ring seal has a generally rectangular cross section, and wherein the ring seal is installed in the channel either before or after the compressor wheel is connected to the shaft.

13. The method of claim 10, wherein the tortuous path is created along an interface between the bearing retainer and the inner race.

14. The method of claim 13, wherein the bearing retainer forms an inwardly facing cylindrical wall around the inner bore, and wherein the tortuous path is defined between the inwardly facing cylindrical wall and the radially outward extending portion, which are axially aligned.

15. The method of claim 10, further comprising stiffening an assembly that includes the inner race and the shaft by providing a flared portion having an increased inner diameter on the inner race with respect to end portions thereof that engage the shaft.

16. The method of claim 15, wherein the shaft is connected to the inner race at end portions, the end portions having a first diameter, the shaft further forming a slender portion between the end portions, the slender portion having a second diameter that is less than the first diameter.

17. The method of claim 16, wherein the increased inner diameter of the inner race overlaps in an axial direction with the slender portion of the shaft.

18. An internal combustion engine having a plurality of combustion chambers formed in a cylinder block, an intake manifold disposed to provide air or a mixture of air with exhaust gas to the combustion chambers, and an exhaust manifold disposed to receive exhaust gas from the combustion chambers, the engine further comprising:

a turbine that includes a turbine housing surrounding a turbine wheel, the turbine housing being fluidly connected to the exhaust manifold and disposed to receive exhaust gas therefrom to drive the turbine wheel;

a compressor that includes a compressor housing that surrounds a compressor wheel, the compressor housing being fluidly connected to the intake manifold and disposed to provide air thereto;

a bearing housing disposed and connected between the turbine and the compressor, the bearing housing forming a bearing bore therethrough that accommodates a shaft interconnecting the turbine wheel and the compressor wheel to transfer power therebetween,

wherein the shaft is rotatably mounted within the bearing housing and extends into the turbine and the compressor such that the turbine wheel is connected to one end of the shaft and the compressor wheel is connected to an opposite end of the shaft;

first and second bearings disposed between the shaft and the bearing housing, the first and second bearings formed by a respective first and second plurality of rollers, respectively;

an outer race disposed within the bearing bore and respectively including a first outer race portion and a second outer race portion;

an inner race disposed within the outer race and between the outer race and the shaft, the inner race respectively including a first inner race portion and a second inner race portion, the first inner race portion being axially aligned with the first outer race portion, and the second inner race portion being axially aligned with the second outer race portion;

a bearing retainer connected between the bearing housing and the compressor, the bearing retainer forming an inner bore through which the shaft extends,

wherein the inner race is arranged to rotate with the shaft, and

wherein the inner race forms an extension segment extending up to the compressor wheel, the extension segment forming an open channel that, together with an annular surface on an inner side of a back of the compressor wheel that faces the shaft, forms a U-shaped channel; and

a ring seal disposed in the U-shaped channel, the ring seal sealably engaging the inner bearing race element and also slidably and sealably engaging the inner bore of the bearing retainer,

wherein an end face of the inner race forms a radially outward extending portion that slopes away from the shaft to centrifuge oil away from the ring seal and towards the first and second bearings, and

wherein a tortuous path is provided between an oil collection gallery of the bearing housing and the ring seal.