Sealing method for a turbocharger shaft seal and corresponding turbocharger

摘要

A turbocharger has a sealing arrangement between the turbocharger shaft and the bearing housing adjacent to the turbine and/or the compressor housings to restrict leaking of gas into the bearing housing. At least a pair of spaced sealing rings project from an annular surface of the bearing housing into corresponding annular recesses formed on the shaft. The trailing face of the second ring or the opposite surface of the recess has a plurality of radial grooves that define leak passages that serve to maintain a very small flow of gas from the turbine or compressor housing into the bearing housing. Alternatively there is a slot in the second ring to provide the leak passage. This ensures that there is a minimum gas flow so that a large pressure gradient is not applied across the second seal thereby avoiding wear, overheating and collapse of the ring.