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US 8,075,251 B2Granted
Hydraulic seal for a turbocharger
AssigneeCummins Turbo Technologies Limited
InventorMatthew J Purdey
Life of this patent
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AssigneeCummins Turbo Technologies Limited
InventorMatthew J Purdey
Estimating the term…
A hydraulic seal is defined between a rotating member such as a turbocharger shaft and a stationary member such as part of a bearing housing of a turbocharger. The members define a projecting annular disc that is received in an annular channel that is filled with hydraulic sealing fluid such as oil. Rotation of the rotary member applies a centrifugal force to the fluid thereby ensuring that it is retained in the channel between walls thereof and the disc. This annulus of fluid provides a hydraulic seal around the shaft between the bearing housing and the compressor or turbine housing. The oil is delivered into the channel from a supply in the rotary member. One of the walls of the channel serves as a weir whereby when the channel has an excess supply of oil is overflows the wall and passes the drain. The arrangement provides an effective seal against blow-by across the turbine end seal and restricts gas flow from the relatively high pressure regions of the compressor and turbine housings into the relatively low pressure area of the bearing housing. It also ensures that there is a continuous flow of oil across the seal so as to prevent it degrading in the high temperature environment.
A turbocharger comprising:
A hydraulic seal assembly comprising a rotary member that is rotatable about an axis of rotation and a fixed member, the rotary member defining an annular projection and the fixed member defining a radially inward open annular channel in which said annular projection is received such that it defines a clearance between the members for receipt of hydraulic sealing fluid, whereby rotation of the rotary member imparts a centrifugal force to the fluid, when present, so as to maintain an annulus of sealing fluid in the clearance, a sealing fluid supply for delivering sealing fluid to said channel, the supply defining a fluid inlet at which the fluid may enter the channel, the inlet being disposed in said channel at a first distance from said axis of rotation, wherein the channel is defined between a base wall and first and second substantially opposite walls that extend from the base wall towards the axis of rotation, and a sealing fluid exit in or at an end of said first wall, the inlet and exit being axially offset, wherein the rotary member comprises a sleeve from which the annular projection extends, wherein the fluid inlet is configured to receive fluid from a thrust bearing assembly adjacent to said hydraulic seal assembly.
Dependencies are inferred from the claim text.