Turbocharger and method

• US 9,752,536 B2
• Filed: 03/09/2015
• Issued: 09/05/2017
• Est. Priority Date: 03/09/2015
• Status: Active Grant

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Annati, Richard E., Powers, Gary W., McCormack, Jeffrey W., Williams, Thomas J.
• Primary Examiner(s): Trieu, Thai Ba
• Application Number:
  US14/641,682
• Publication Number:
  US 20160281648A1
• Time in Patent Office: 911 Days
• Field of Search: 606051, 606052, 606053, 417406-407, 384 99, 384475, 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: F02M 26/04 with a single turbocharger
• 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 33/767 integral with the race
• CPC Class Codes: F16C 35/067 Fixing them in a housing 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 an outer bearing race element and an inner bearing race element rotatably disposed within the outer bearing race element. The inner bearing race element forms a hollow extension extending up to the compressor wheel, the extension having a hollow cylindrical shape that surrounds a portion of the shaft that is connected on one end to the compressor wheel and at another end is disposed adjacent to a seat formed on the extension portion around the shaft, and a nut engaged on the shaft and disposed within the extension at an offset distance from the seat.

Claims

1. 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;

wherein the inner race forms an extension extending up to the compressor wheel, the extension including an inner race cylindrical bore that surrounds a portion of the shaft that is connected on one end to the compressor wheel and at another end is disposed adjacent to a seat formed on the extension portion around the shaft; and

a nut disposed within the inner race cylindrical bore of the extension, the nut being engaged on the shaft and disposed at an offset distance from the seat.

2. The method of claim 1, wherein the inner race forms an interior space between areas of engagement with the shaft, the interior space being free of oil.

3. The method of claim 1, wherein in the event of a failure of the turbocharger that includes motion of the shaft towards the turbine, the nut is configured to be pulled towards the turbine along with the shaft such that the nut abuts the seat formed on the extension portion to halt motion of the shaft relative to the inner race.

4. The turbocharger of claim 3, wherein a ring seal disposed between the bearing housing and the compressor is configured to slide a distance equal to the offset distance and still maintain sealing capability.

5. The method of claim 3, wherein the failure of the turbocharger includes a separation of rolling engagement structures with respective race channels formed between the outer race and the inner race.

6. The method of claim 1, wherein the offset distance from the seat is 1 mm, and wherein a ring seal disposed to seal the shalt with an inner bore formed between the bearing housing and the turbine sealably and rotatably contact the inner bore is movable by a distance of 1 mm while still maintaining contact with the inner bore.

7. The method of claim 1, 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.

8. The method of claim 7, 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.

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

10. 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 between an outer race; and

an inner race, which engages the shaft and is rotatably disposed within the outer race;

wherein the inner race forms an extension extending up to the compressor wheel, the extension including an inner race cylindrical bore that surrounds a portion of the shaft that is connected on one end to the compressor wheel and at another end is disposed adjacent to a seat formed on the extension portion around the shaft; and

a nut disposed within the inner race cylindrical bore of the extension, the nut being engaged on the shaft and disposed at an offset distance from the seat.

11. 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;

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, the first and second bearings including an outer race disposed in the bearing bore, wherein the outer race has a hollow cylindrical shape, and an inner race, which engages the shaft and is rotatably disposed within the outer race;

wherein the inner race forms an extension extending up to the compressor wheel, the extension including an inner race cylindrical bore that surrounds a portion of the shaft that is connected on one end to the compressor wheel and at another end is disposed adjacent to a seat formed on the extension portion around the shaft;

wherein the inner race forms an interior space between areas of engagement with the shaft, the interior space being free of oil;

a nut disposed within the inner race cylindrical bore of the extension, the nut being engaged on the shaft and disposed at an offset distance from the seat; and

a ring seal disposed at least one of between the bearing housing and the compressor, and between the bearing housing and the turbine;

wherein during a failure of the turbocharger that includes motion of the shaft towards the turbine, the nut is configured to be pulled towards the turbine along with the shaft such that the nut abuts the seat formed on the extension portion to halt motion of the shaft relative to the inner race;

wherein the ring seal disposed between the bearing housing and the compressor is configured to slide a distance equal to the offset distance and still maintain sealing capability;

wherein the offset distance from the seat is 1 mm;

wherein the failure of the turbocharger includes a separation of rolling engagement structures with respective race channels formed between the outer race and the inner race; and

wherein the ring seal disposed between the bearing housing and the turbine to seal the shaft with an inner bore sealably and rotatably contacts the inner bore being movable by a distance of 1 mm while still maintaining contact with the inner bore.