Importance

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Abstract

A turbocharger for an internal combustion engine is of the type having an impeller mounted on a shaft carried by a bearing supplied with lubricating oil, the shaft being located in a bore and having an oil and air seal between the bearing and the impeller hub. The seal is a floating ring seal mounted in the bore and extending radially into a circumferential recess in the impeller hub. In use, the ring seal experiences a pressure differential across it which urges it to slide axially along the bore so that it forms a sealing interface with a side face of the recess. The shaft rotates relative to the ring seal, which is therefore subject to wear against the side face of the recess. Hence, a shoulder is provided in the bore to limit excessive axial sliding of the ring seal due to wearing away of the ring seal against the side face of the recess. Sealing performance is improved and rate of wear of the ring seal is reduced by providing the ring seal with at least one inwardly-facing annular groove and providing the recess with a circumferential rib corresponding to each groove, each rib being receivable in a groove, whereby under the pressure differential a side of each groove forms a sealing interface with a side of the corresponding rib.

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First Claim