초록 ▼

A variable-nozzle turbocharger includes a cartridge containing a variable vane mechanism connected between the center housing and the turbine housing. The cartridge comprises an annular nozzle ring supporting an array of rotatable vanes, an insert having a tubular portion sealingly received into the

A variable-nozzle turbocharger includes a cartridge containing a variable vane mechanism connected between the center housing and the turbine housing. The cartridge comprises an annular nozzle ring supporting an array of rotatable vanes, an insert having a tubular portion sealingly received into the bore of the turbine housing and having a nozzle portion extending radially out from one end of the tubular portion and being axially spaced from the nozzle ring with the vanes therebetween, and a plurality of spacers connected between the nozzle portion of the insert and the nozzle ring. The turbine housing has a surface that directly contacts a surface of the nozzle ring that axially faces the insert for axially locating the nozzle ring relative to the turbine housing. A radial gap is defined between the turbine housing and the nozzle ring to allow radial movement of the nozzle ring relative to the turbine housing.

대표청구항 ▼

What is claimed is: 1. A turbocharger having a variable-nozzle turbine, comprising: a turbine assembly comprising a turbine housing and a turbine wheel mounted in the turbine housing and connected to a rotatable shaft for rotation therewith, the turbine housing defining a chamber surrounding the tu

What is claimed is: 1. A turbocharger having a variable-nozzle turbine, comprising: a turbine assembly comprising a turbine housing and a turbine wheel mounted in the turbine housing and connected to a rotatable shaft for rotation therewith, the turbine housing defining a chamber surrounding the turbine wheel for receiving exhaust gas from an engine and for supplying the exhaust gas to the turbine wheel, the turbine assembly defining a nozzle leading from the chamber generally radially inwardly to the turbine wheel, the turbine housing further defining an axially extending bore through which exhaust gas is discharged after passing through the turbine wheel; a compressor assembly comprising a compressor housing and a compressor wheel mounted in the compressor housing and connected to the rotatable shaft for rotation therewith; a center housing connected between the compressor housing and the turbine housing; and a cartridge connected between the center housing and the turbine housing, the cartridge comprising an assembly of: a generally annular nozzle ring and an array of vanes circumferentially spaced about the nozzle ring and disposed in the nozzle such that exhaust gas flows between the vanes to the turbine wheel, each vane being rotatably mounted to the nozzle ring and connected to a rotatable actuator ring such that rotation of the actuator ring rotates the vanes for regulating exhaust gas flow to the turbine wheel, wherein the nozzle ring includes a radially outer surface facing a radially inner surface of the turbine housing, and wherein a radial gap is defined between the radially outer surface of the nozzle ring and the radially inner surface of the turbine housing, the radial gap allowing radial displacement of the radially outer surface of the nozzle ring relative to the turbine housing; an insert having a tubular portion sealingly received into the bore of the turbine housing and having a nozzle portion extending generally radially out from one end of the tubular portion, the nozzle portion being axially spaced from the nozzle ring such that the vanes extend between the nozzle ring and the nozzle portion; and a plurality of spacers connected between the nozzle portion of the insert and the nozzle ring for securing the nozzle ring to the insert and maintaining an axial spacing between the nozzle portion of the insert and the nozzle ring; wherein the turbine housing includes a surface directly contacting a surface of the nozzle ring that faces axially toward the insert for axially locating the nozzle ring relative to the turbine housing, and the nozzle ring is structured and arranged relative to the center housing such that radial locating of the nozzle ring is performed by the center housing. 2. The turbocharger of claim 1, wherein a radially inwardly facing surface of the nozzle ring directly contacts a radially outwardly facing surface of the center housing to radially locate the nozzle ring relative to the center housing. 3. The turbocharger of claim 2, wherein the radially inwardly facing surface of the nozzle ring is configured to reduce a contact area with the radially outwardly facing surface of the center housing. 4. The turbocharger of claim 3, wherein the radially inwardly facing surface of the nozzle ring defines a plurality of circumferentially spaced recesses, regions between the recesses defining the radially inwardly facing surface that contacts the radially outwardly facing surface of the center housing and provides radial centering of the nozzle ring relative to the center housing. 5. The turbocharger of claim 1, wherein the radially outwardly facing surface of the center housing is configured to reduce a contact area with the radially inwardly facing surface of the nozzle ring. 6. The turbocharger of claim 5, wherein the radially outwardly facing surface of the center housing defines a plurality of circumferentially spaced projections that project radially outward to contact the radially inwardly facing surface of the nozzle ring and provide radial centering of the nozzle ring relative to the center housing. 7. The turbocharger of claim 1, further comprising an elastically deformable heat shroud disposed between the nozzle ring and the center housing, an axially facing surface of the nozzle ring contacting an outer portion of the heat shroud proximate an outer diameter thereof and urging the heat shroud toward the center housing such that an inner portion of the heat shroud proximate an inner diameter thereof is urged against a surface of the center housing, the heat shroud being elastically deformed between the nozzle ring and center housing. 8. The turbocharger of claim 1, further comprising a ring-shaped sleeve disposed between the radially inwardly facing surface of the nozzle ring and the radially outwardly facing surface of the center housing, the sleeve having a radially inner surface contacting the radially outwardly facing surface of the center housing and having a radially outer surface contacting the radially inwardly facing surface of the nozzle ring so as to center the nozzle ring relative to the center housing. 9. The turbocharger of claim 8, wherein the sleeve defines a plurality of circumferentially spaced projections that project radially outwardly and define the radially outer surface that contacts the nozzle ring, the projections reducing a contact area with the nozzle ring. 10. The turbocharger of claim 9, wherein the sleeve at one circumferential location thereof defines a radially outwardly extending protuberance that extends out to a larger radius than the plurality of circumferentially spaced projections, the nozzle ring at one circumferential location thereof defining a recess for receiving the protuberance such that the nozzle ring is oriented in a predetermined circumferential orientation with respect to the sleeve. 11. The turbocharger of claim 10, wherein the sleeve and center housing define cooperative features that engage each other for orienting the sleeve in a predetermined circumferential orientation relative to the center housing. 12. The turbocharger of claim 1, further comprising a split compensating ring disposed between the radially inwardly facing surface of the nozzle ring and the radially outwardly facing surface of the center housing, the compensating ring having a radially inner surface contacting the radially outwardly facing surface of the center housing and having a radially outer surface contacting the radially inwardly facing surface of the nozzle ring so as to center the nozzle ring relative to the center housing. 13. The turbocharger of claim 12, wherein the compensating ring is radially undulating along the circumferential direction for reducing contact area with the nozzle ring and center housing. 14. The turbocharger of claim 1, further comprising an elastically deformable spring sleeve disposed between the radially inwardly facing surface of the nozzle ring and the radially outwardly facing surface of the center housing, the spring sleeve having a radially inner surface contacting the radially outwardly facing surface of the center housing and having a radially outer surface contacting the radially inwardly facing surface of the nozzle ring so as to center the nozzle ring relative to the center housing. 15. The turbocharger of claim 14, wherein the spring sleeve has a generally S-shaped cross-section. 16. The turbocharger of claim 14, wherein the nozzle ring defines an axially facing surface that faces the center housing, and the center housing defines an axially facing surface that faces the turbine wheel, and further comprising a heat shroud having a radially outer portion disposed between and contacting the spring sleeve and the axially facing surface of the nozzle ring. 17. The turbocharger of claim 16, wherein the spring sleeve is elastically deformed between the heat shroud and the axially facing surface of the center housing. 18. The turbocharger of claim 17, wherein the heat shroud is free from contact with the center housing. 19. The turbocharger of claim 1, further comprising a heat shroud providing shielding of the center housing from exhaust gas passing through the turbine, the heat shroud disposed between the radially inwardly facing surface of the nozzle ring and the radially outwardly facing surface of the center housing, the heat shroud having a radially inner surface contacting the radially outwardly facing surface of the center housing and having a radially outer surface contacting the radially inwardly facing surface of the nozzle ring so as to center the nozzle ring relative to the center housing. 20. The turbocharger of claim 19, wherein the nozzle ring defines an axially facing surface that faces the center housing, and the center housing defines an axially facing surface that faces the turbine wheel, and wherein the heat shroud engages the axially facing surfaces of the nozzle ring and center housing. 21. The turbocharger of claim 1, wherein the center housing includes an axially extending annular flange that passes radially outwardly of the radially outer surface of the nozzle ring, the flange defining a radially inner surface, and further comprising a seal member disposed between and contacting the radially outer surface of the nozzle ring and the radially inner surface of the flange so as to center the nozzle ring relative to the center housing. 22. The turbocharger of claim 21, wherein the seal member comprises a resiliently deformable seal ring. 23. The turbocharger of claim 22, wherein the seal ring is resiliently deformed in the radial direction between the radially outer surface of the nozzle ring and the radially inner surface of the flange.