Turbocharger and method

An internal combustion engine having a plurality of combustion chambers formed in a cylinder block, an intake manifold disposed to provide air or a mixture of air with exhaust gas to the combustion chambers, and an exhaust manifold disposed to receive exhaust gas from the combustion chambers, the engine further comprising:

• a turbine that includes a turbine housing surrounding a turbine wheel, the turbine housing being fluidly connected to the exhaust manifold and disposed to receive exhaust gas therefrom to drive the turbine wheel;
• a compressor that includes a compressor housing that surrounds a compressor wheel, the compressor housing being fluidly connected to the intake manifold and disposed to provide air thereto;
• a bearing housing disposed and connected between the turbine and the compressor, the bearing housing forming a bearing bore therethrough that accommodates a shaft interconnecting the turbine wheel and the compressor wheel to transfer power therebetween;
• wherein the shaft is rotatably mounted within the bearing housing and extends into the turbine and the compressor such that the turbine wheel is connected to one end of the shaft and the compressor wheel is connected to an opposite end of the shaft;
• first and second bearings disposed between the shaft and the bearing housing, the first and second bearings formed between an outer race;
• and an inner race, which engages the shaft and is rotatably disposed within the outer race;
• wherein the inner race forms an extension extending up to the compressor wheel, the extension including an inner race cylindrical bore that surrounds a portion of the shaft that is connected on one end to the compressor wheel and at another end is disposed adjacent to a seat formed on the extension portion around the shaft;
• and
• a nut disposed within the inner race cylindrical bore of the extension, the nut being engaged on the shaft and disposed at an offset distance from the seat.

A turbocharger, comprising:

• a turbine that includes a turbine wheel;
• a compressor that includes a compressor wheel;
• a bearing housing disposed and connected between the turbine and the compressor, the bearing housing forming a bearing bore;
• a shaft rotatably disposed within the bearing housing and extending into the turbine and the compressor, wherein the turbine wheel is connected to one end of the shaft and wherein the compressor wheel is connected to an opposite end of the shaft such that the turbine wheel is rotatably disposed in the turbine and the compressor wheel is rotatably disposed in the compressor;
• first and second bearings disposed between the shaft and the bearing housing, the first and second bearings including an outer race disposed in the bearing bore, wherein the outer race has a hollow cylindrical shape, and an inner race, which engages the shaft and is rotatably disposed within the outer race;
• wherein the inner race forms an extension extending up to the compressor wheel, the extension including an inner race cylindrical bore that surrounds a portion of the shaft that is connected on one end to the compressor wheel and at another end is disposed adjacent to a seat formed on the extension portion around the shaft;
• wherein the inner race forms an interior space between areas of engagement with the shaft, the interior space being free of oil;
• a nut disposed within the inner race cylindrical bore of the extension, the nut being engaged on the shaft and disposed at an offset distance from the seat;
• and
• a ring seal disposed at least one of between the bearing housing and the compressor, and between the bearing housing and the turbine;
• wherein during a failure of the turbocharger that includes motion of the shaft towards the turbine, the nut is configured to be pulled towards the turbine along with the shaft such that the nut abuts the seat formed on the extension portion to halt motion of the shaft relative to the inner race;
• wherein the ring seal disposed between the bearing housing and the compressor is configured to slide a distance equal to the offset distance and still maintain sealing capability;
• wherein the offset distance from the seat is 1 mm;
• wherein the failure of the turbocharger includes a separation of rolling engagement structures with respective race channels formed between the outer race and the inner race;
• and
• wherein the ring seal disposed between the bearing housing and the turbine to seal the shaft with an inner bore sealably and rotatably contacts the inner bore being movable by a distance of 1 mm while still maintaining contact with the inner bore.