Turbocharger waste-gate valve bushing

Patent metadata

Field	Value
Publication number	US-9546597-B2
Application number	US-201414490712-A
Country	US
Kind code	B2
Filing date	Sep 19, 2014
Priority date	Sep 19, 2014
Publication date	Jan 17, 2017
Grant date	Jan 17, 2017

Abstract

A turbocharger for an internal combustion engine includes a rotating assembly having a turbine wheel disposed inside a turbine housing and a compressor wheel disposed inside a compressor cover. The turbocharger also includes a waste-gate assembly configured to selectively redirect at least a portion of the engine's post-combustion gases away from the turbine wheel. The waste-gate assembly includes a valve, a rotatable shaft connected to the valve, and a bushing fixed relative to the turbine housing and disposed concentrically around the shaft such that the shaft rotates inside the bushing for opening and closing the valve. The bushing is defined by a length, an outer surface in contact with the turbine housing, and an inner surface in contact with the shaft. The inner surface includes a plurality of longitudinal grooves configured to counteract friction between the bushing and the shaft and avoid seizure of the shaft relative to the bushing.

First claim

The invention claimed is:

1. A turbocharger for pressurizing an airflow for delivery to an internal combustion engine that generates post-combustion gases, the turbocharger comprising:
a turbine housing and a compressor cover;
a rotating assembly having a turbine wheel disposed inside the turbine housing and a compressor wheel disposed inside the compressor cover, wherein the rotating assembly is rotated about an axis by the post-combustion gases; and
a waste-gate assembly configured to selectively redirect at least a portion of the post-combustion gases away from the turbine wheel and thereby limit rotational speed of the rotating assembly and a pressure of the airflow received from the ambient, the waste-gate assembly having:
a valve, a rotatable shaft connected to the valve, and a bushing fixed relative to the turbine housing and disposed concentrically around the shaft such that the shaft rotates inside the bushing to thereby selectively open and close the valve;
wherein the bushing is defined by a length, an outer surface in contact with the turbine housing, and an inner surface in contact with the shaft, and wherein the inner surface includes a plurality of longitudinal grooves configured to counteract friction between the bushing and the shaft and avoid seizure of the shaft relative to the bushing.

2. The turbocharger of claim 1 , wherein at least one of the longitudinal grooves includes a low-friction material.

3. The turbocharger of claim 2 , wherein the low-friction material is graphite.

4. The turbocharger of claim 2 , wherein the low-friction material is a ceramic-based material.

5. The turbocharger of claim 4 , wherein the ceramic-based material is one of a silicon carbide, silicon nitride, chromium carbide, zirconia, carbon-carbon composite, and metal-ceramic composite.

6. The turbocharger of claim 1 , wherein the longitudinal grooves are evenly spaced around the inner surface and extend out toward the outer surface.

7. The turbocharger of claim 6 , wherein the plurality of longitudinal grooves includes four individual grooves.

8. The turbocharger of claim 1 , wherein at least one of the plurality of longitudinal grooves extends along at least 75% of the length of the bushing.

9. The turbocharger of claim 1 , wherein at least one of the plurality of longitudinal grooves is configured to collect particulates to thereby reduce the friction between the bushing and the shaft.

10. The turbocharger of claim 1 , further comprising a locating feature configured to set the bushing relative to the turbine housing.

11. An internal combustion engine comprising:
a cylinder configured to receive an air-fuel mixture for combustion therein;
a reciprocating piston disposed inside the cylinder and configured to exhaust post-combustion gases therefrom; and
a turbocharger in fluid communication with the piston and configured to pressurize an airflow being received from the ambient and deliver the pressurized airflow to the cylinder, the turbocharger including:
a turbine housing and a compressor cover;
a rotating assembly having a turbine wheel disposed inside the turbine housing and a compressor wheel disposed inside the compressor cover, wherein the rotating assembly is rotated about an axis by the post-combustion gases; and
a waste-gate assembly configured to selectively redirect at least a portion of the post-combustion gases away from the turbine wheel and thereby limit rotational speed of the rotating assembly and a pressure of the airflow received from the ambient, the waste-gate assembly having:
a valve, a rotatable shaft connected to the valve, and a bushing fixed relative to the turbine housing and disposed concentrically around the shaft such that the shaft rotates inside the bushing to thereby selectively open and close the valve;
wherein the bushing is defined by a length, an outer surface in contact with the turbine housing, and an inner surface in contact with the shaft, and wherein the inner surface includes a plurality of longitudinal grooves configured to counteract friction between the bushing and the shaft and avoid seizure of the shaft relative to the bushing.

12. The engine of claim 11 , wherein at least one of the longitudinal grooves includes a low-friction material.

13. The engine of claim 12 , wherein the low-friction material is graphite.

14. The engine of claim 12 , wherein the low-friction material is a ceramic-based material.

15. The engine of claim 14 , wherein the ceramic-based material is one of a silicon carbide, silicon nitride, chromium carbide, zirconia, carbon-carbon composite, and metal-ceramic composite.

16. The engine of claim 11 , wherein the longitudinal grooves are evenly spaced around the inner surface and extend out toward the outer surface.

17. The engine of claim 16 , wherein the plurality of longitudinal grooves includes four individual grooves.

18. The engine of claim 11 , wherein at least one of the plurality of longitudinal grooves extends along at least 75% of the length of the bushing.

19. The engine of claim 11 , wherein at least one of the plurality of longitudinal grooves is configured to collect particulates to thereby reduce the friction between the bushing and the shaft.

20. The engine of claim 11 , wherein the turbocharger includes a locating feature configured to set the bushing relative to the turbine housing.

Assignees

• Gm Global Tech Operations Llc

Inventors

• Swartz Julie
• Bielas Robert
• Begin Louis P
• Mudel Roman

Classifications

• F05D2300/30

  Inorganic materials other than provided for in groups F05D2300/10 - F05D2300/2291 · CPC title

• F05D2300/516

  Surface roughness · CPC title

• F05D2220/40

  in turbochargers · CPC title

• F05D2240/54

  Radial bearings · CPC title

• F01D17/105

  by passing part of the fluid · CPC title