Turbocharger bearing assembly and lubrication thereof
AssigneeCummins Turbo Technologies Limited
InventorsMatthew J. Purdey, Mohammed Hanif Khan
Life of this patent
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Abstract
A turbocharger bearing housing defines a bore in which the turbocharger shaft is mounted for rotation in journal bearings. Lubricating oil is delivered to the journal bearings and a residue is retained in reservoirs in which the journal bearings are located. Two fluid retaining members are disposed around the shaft, each forming a wall of the reservoir and being sealed to the bearing housing. The lubricating fluid reservoir is provided between the fluid retaining members to a depth that at least partially immerses the journal bearings even when the oil supply is interrupted. This ensures that there is sufficient oil to lubricate the bearings at engine start-up, thereby reducing the risk of wear.
Claims20
A turbocharger comprising:
- a turbocharger shaft for rotation about an axis and for supporting a compressor wheel at first end and a turbine wheel at a second end;
- a bearing housing having a wall defining a bore in which the shaft is received with a substantially annular clearance, the shaft being supported for rotation in the bore by at least one journal bearing housed within the annular clearance;
- a first gas seal between the shaft and the bearing housing proximate the first end of the shaft;
- a second gas seal between the shaft and the bearing housing proximate the second end of the shaft;
- at least one fluid passage for delivering lubricating fluid from a fluid source to the at least one journal bearing;
- at least two fluid retaining members disposed around the shaft and each having an outer portion that is sealed to the wall;
- and
- the at least one journal bearing being disposed at an axial position between fluid retaining members so that, in use when the turbocharger shaft is not rotating, a volume of lubricating fluid is retained in at least one lubricating fluid reservoir defined between the fluid retaining members and the wall to a depth that at least partially immerses the journal bearing.
Dependencies are inferred from the claim text.