Turbocharger and Method

Patent metadata

Field	Value
Publication number	US-2016281648-A1
Application number	US-201514641682-A
Country	US
Kind code	A1
Filing date	Mar 9, 2015
Priority date	Mar 9, 2015
Publication date	Sep 29, 2016
Grant date	—

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.

First claim

We claim:

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; 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; a bearing arrangement disposed between the shaft and the bearing housing, the bearing arrangement including an outer bearing race element disposed in the bearing bore, wherein the outer bearing race element has a hollow cylindrical shape, and an inner bearing race element, which engages the shaft and is rotatably disposed within the outer bearing race element; wherein the inner bearing race element forms an 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.

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

3 . The turbocharger 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 bearing race element.

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

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

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

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

10 . The turbocharger of claim 1 , wherein the inner bearing race element is formed by two components, a compressor-side cup and a turbine-side cup, and wherein a nut engages the compressor-side cup to the shaft.

11 . 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 rolling elements in a first inner race formed in an inner bearing race element and in a first outer race formed in an outer bearing race element; forming a second roller bearing by engaging a second plurality or rolling elements in a second inner race formed in the inner bearing race element and in a second outer race formed in the outer bearing race element; engaging the outer bearing race element between a bearing bore formed in the bearing housing and the shaft, which extends through the bearing bore, such that the inner bearing race element rotates with the shaft with respect to the outer bearing race element; wherein the inner bearing race element forms an 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.

12 . The method of claim 11 , wherein the inner bearing race element forms an interior space between areas of engagement with the shaft, the interior space being free of oil.

13 . The method of claim 11 , 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 bearing race element.

14 . The turbocharger of claim 13 , 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.

15 . The method of claim 13 , wherein the failure of the turbocharger includes a separation of rolling engagement structures with respective race channels formed between the outer bearing race element and the inner bearing race element.

16 . The method of claim 11 , wherein the offset distance from the seat is about 1 mm, and wherein ring seals disposed to seal the shaft with an inner bore formed between the bearing housing and the turbine sealably and rotatably contact the inner bore are movable by a distance of about 1 mm while still maintaining contact with the inner bore.

17 . The method of claim 11 , further comprising stiffening an assembly that includes the inner bearing race element and the shaft by providing a flared portion having an increased inner diameter on the inner bearing race element with respect to end portions thereof that engage the shaft.

18 . The method of claim 17 , wherein the shaft is connected to the inner bearing race element 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.

19 . The method of claim 18 , wherein the increased inner diameter of the inner bearing race element overlaps in an axial direction with the slender portion of the shaft.

20 . 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 disp

Assignees

• Caterpillar Inc

Inventors

• Annati Richard E
• Powers Gary W
• Mccormack Jeffrey W
• Williams Thomas J

Classifications

• F01D25/24

  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 title

• F01D25/16 Primary

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

• F02M25/0706 Primary

  Mechanical Engineering · mapped topic

• F16C33/767

  integral with the race · CPC title

• F16C35/067

  Fixing them in a housing (with interposition of an element F16C35/07) · CPC title