Turbocharger bearing system

A turbocharger bearing system for carrying a turbocharger shaft for rotation at very high speeds in the presence of very high turbocharger temperatures, comprising

• a turbocharger bearing housing including a cylindrical bearing surface,
• an outer bearing element having an outer cylindrical bearing surface adapted to be rotatably carried within the cylindrical bearing surface of the turbocharger bearing housing by a film of lubricant, said outer bearing element having two spaced inwardly projecting portions, each inwardly projecting portion of the outer bearing element having an inner cylindrical journal bearing surface for carrying a cylindrical turbocharger shaft portion by a film of lubricant and having an outer side thrust bearing surface positioned in-between said inner cylindrical journal bearing surface and said outer cylindrical bearing surface, said two spaced inwardly projecting portions forming with the turbocharger shaft a centrally located lubricant reservoir,
• said turbocharger shaft including a thrust bearing surface projecting radially therefrom to respective locations adjacent each said outer side thrust bearing surface of the inwardly projecting portions of the outer bearing element and adapted to transfer to the outer bearing element, thrust from the turbocharger shaft to the outer bearing element in the two opposing axial directions of the turbocharger shaft,
• said turbocharger shaft includes a shallow shoulder adjacent its turbine end and the thrust bearing surface at the turbine end of the turbocharger shaft is part of a separate element held against the shallow shoulder of the turbocharger shaft to reduce heat transfer from the turbine end of the turbocharger bearing system,
• said turbocharger bearing housing, outer bearing element and turbocharger shaft being adapted to provide a flow of lubricant from outside the turbocharger bearing housing to between the cylindrical bearing surface of the turbocharger bearing housing and the outer cylindrical bearing surface of the outer bearing element, and through the centrally located lubricant reservoir, and outwardly between the inner cylindrical journal bearing surfaces and the outer side thrust bearing surfaces of the inwardly projecting portions of the outer bearing surface, and between the cylindrical turbocharger shaft portions and thrust bearing surfaces of the turbocharger shaft adjacent each outer side thrust bearing surface of the outer bearing element to rotatably carry the turbocharger shaft and transfer thrust from the rotating turbocharger shaft to the outer bearing element in both axial directions of the turbocharger shaft.

A turbocharger bearing system for carrying a turbocharger shaft for rotation at very high speeds in the presence of very high turbocharger temperatures, comprising

• a turbocharger bearing housing including a cylindrical bearing surface,
• an outer bearing element having an outer cylindrical bearing surface adapted to be rotatably carried within the cylindrical bearing surface of the turbocharger bearing housing by a film of lubricant, said outer bearing element having two spaced inwardly projecting portions, each inwardly projecting portion of the outer bearing element having an inner cylindrical journal bearing surface for carrying a cylindrical turbocharger shaft portion by a film of lubricant and having an outer side thrust bearing surface positioned in-between said inner cylindrical journal bearing surface and said outer cylindrical bearing surface, said two spaced inwardly projecting portions forming with the turbocharger shaft a centrally located lubricant reservoir,
• said turbocharger shaft including a thrust bearing surface projecting radially therefrom to respective locations adjacent each said outer side thrust bearing surface of the inwardly projecting portions of the outer bearing element and adapted to transfer to the outer bearing element, thrust from the turbocharger shaft to the outer bearing element in the two opposing axial directions of the turbocharger shaft,
• said turbocharger bearing housing, outer bearing element and turbocharger shaft being adapted to provide a flow of lubricant from outside the turbocharger bearing housing to between the cylindrical bearing surface of the turbocharger bearing housing and the outer cylindrical bearing surface of the outer bearing element, and through the centrally located lubricant reservoir, and outwardly between the inner cylindrical journal bearing surfaces and the outer side thrust bearing surfaces of the inwardly projecting portions of the outer bearing surface, and between the cylindrical turbocharger shaft portions and thrust bearing surfaces of the turbocharger shaft adjacent each outer side thrust bearing surface of the outer bearing element to rotatably carry the turbocharger shaft and transfer thrust from the rotating turbocharger shaft to the outer bearing element in both axial directions of the turbocharger shaft,
• said turbocharger shaft includes a shallow shoulder adjacent its turbine end and includes an elongated sleeve with an outwardly projecting flange held against the shallow shoulder by a turbocharger end cap and lock nut at the compressor end of the turbocharger shaft to rotate with the turbocharger shaft, the outwardly projecting flange of the sleeve forming the turbocharger thrust bearing surface adjacent the outer side thrust bearing surface of the inwardly projecting portion of the outer bearing element at the turbine end of the turbocharger shaft and the turbocharger end cap forming the turbocharger thrust bearing surface adjacent the outer side thrust bearing surface of the inwardly projecting portion of the outer bearing surface at the compressor end of the turbocharger shaft.

A turbocharger bearing system for carrying a turbocharger shaft for rotation in the presence of high turbocharger temperatures, comprising

• a turbocharger bearing housing including an inner cylindrical bearing surface,
• an outer bearing element having an outer cylindrical bearing surface adapted to be rotatably carried within the cylindrical bearing surface of the turbocharger bearing housing by a film of lubricant, said outer bearing element having an inner cylindrical bearing surface for carrying a cylindrical turbocharger shaft portion by a film of lubricant and having outer side thrust bearing surfaces on each of its two opposite ends,
• said turbocharger shaft including a shallow shoulder at its turbine end, and having thrust bearing surfaces projecting radially from an engagement thereto, to respective positions adjacent each outer side thrust bearing surface on each of the opposite ends of the outer bearing element, said thrust bearing surfaces adapted to transfer thrust from the turbocharger shaft to the outer bearing element in the two opposing axial directions of the turbocharger shaft, said thrust bearing surface at the turbine end of the turbocharger shaft being formed on the inner side of a separate flange element seated against the shallow shoulder of the turbocharger shaft and extending outwardly adjacent the outer side thrust bearing surface at the turbine end of the outer bearing element, and said thrust bearing surface at the compressor end of the turbocharger shaft being formed on a separate end cap adjacent the outer side thrust bearing surface of the outer bearing element at the compressor end of the turbocharger shaft, said separate flange and end cap being held to and rotating with the turbocharger shaft,
• said turbocharger bearing housing, outer bearing element and turbocharger shaft being adapted to provide a flow of lubricant from outside the turbocharger bearing housing to between the cylindrical bearing surface of the turbocharger bearing housing and the outer cylindrical bearing surface of the outer bearing element, and through the outer bearing element, and outwardly between the inner cylindrical bearing surface of the outer bearing element and the cylindrical turbocharger shaft portion of the turbocharger shaft, and further between the outer side thrust bearing surfaces of the outer bearing element and thrust bearing surfaces of the turbocharger shaft adjacent each outer side thrust bearing surface of the outer bearing element, thereby reducing heat transfer from the turbine end of the turbocharger to the bearing surface while rotatably carrying the turbocharger shaft and transferring thrust from the rotating turbocharger shaft to the outer bearing element in both axial directions of the turbocharger shaft.