Turbocharger and variable-nozzle cartridge therefor
View Patent ↗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, a plurality of spacers connected between the nozzle portion of the insert and the nozzle ring, and an annular retainer ring fastened to the center housing so as to capture the nozzle ring between the retainer ring and the center housing. The retainer ring is formed as a separate part from the insert ring and is mechanically and thermally decoupled from the insert.
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;
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;
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; and
a generally annular retainer ring fastened to the center housing in such a manner as to capture the nozzle ring between the retainer ring and the center housing, the retainer ring being formed as a separate part from the insert and having no direct contact with either the insert or the turbine housing, such that the retainer ring is mechanically and thermally decoupled from the insert.
2. The turbocharger of claim 1 , wherein the turbine housing is fastened to the center housing in such a manner that a gap is defined between the turbine housing and the retainer ring, the gap providing decoupling between the turbine housing and the retainer ring.
3. The turbocharger of claim 1 , further comprising at least one sealing ring disposed between the tubular portion of the insert and the turbine housing.
4. The turbocharger of claim 3 , wherein the at least one sealing ring is retained in a groove formed in a radially outer surface of the tubular portion of the insert.
5. The turbocharger of claim 4 , wherein the at least one sealing ring spaces the outer surface of the tubular portion of the insert from an opposing inner surface of the turbine housing so as to substantially decouple the insert from the turbine housing.
6. The turbocharger of claim 1 , wherein the spacers are formed separately from the nozzle ring and the insert.
7. The turbocharger of claim 6 , wherein the nozzle ring defines apertures that receive first end portions of the spacers.
8. The turbocharger of claim 7 , wherein each of the spacers has a first shoulder that is abutted by a face of the nozzle ring when the first end portion of the spacer is received in one of the apertures, the shoulders delimiting the axial spacing between the nozzle ring and the nozzle portion of the insert.
9. The turbocharger of claim 8 , wherein the nozzle portion of the insert defines apertures that receive opposite second end portions of the spacers, each of the spacers having a second shoulder that abuts a face of the nozzle portion when the second end portion is received in one of the apertures of the nozzle portion.
10. The turbocharger of claim 1 , wherein the retainer ring has an axially facing surface circumference so as to substantially seal an interface between the retainer ring and the nozzle ring.
11. The turbocharger of claim 1 , wherein the nozzle ring includes a radially outer surface facing a radially inner surface of the retainer ring, and wherein a radial gap is defined between the radially outer surface of the nozzle ring and the radially inner surface of the retainer ring, the radial gap allowing radial displacement of the nozzle ring relative to the retainer ring.
12. A variable-nozzle turbine for a turbocharger, 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 generally annular nozzle ring and an array of vanes circumferentially spaced about the nozzle ring, each vane being rotatably mounted to the nozzle ring and connected to a rotatable actuator ring such that rotation of the actuator ring relative to the nozzle ring rotates the vanes for regulating exhaust gas flow through the array of vanes;
an insert having a tubular portion sealingly received into the bore of a 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;
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; and
a generally annular retainer ring structured and arranged to be fastened to a center housing of the turbocharger in such a manner as to capture the nozzle ring between the retainer ring and the center housing, the retainer ring being formed as a separate part from the insert and having no direct contact with either the insert or the turbine housing, such that the retainer ring is mechanically and thermally decoupled from the insert.
13. The variable-nozzle turbine of claim 12 , further comprising at least one sealing ring retained in a groove formed in a radially outer surface of the tubular portion of the insert for sealing against a surface of the bore of the turbine housing.
14. The variable-nozzle turbine of claim 12 , wherein the spacers are joined to the nozzle portion of the insert and project axially therefrom.
15. The variable-nozzle turbine of claim 14 , wherein the nozzle ring defines apertures that receive first end portions of the spacers.
16. The variable-nozzle turbine of claim 15 , wherein each of the spacers has a first shoulder that is abutted by a face of the nozzle ring when the first end portion of the spacer is received in one of the apertures, the shoulders delimiting the axial spacing between the nozzle ring and the nozzle portion of the insert.
17. The variable-nozzle turbine of claim 16 , wherein the tubular portion of the insert defines apertures that receive opposite second end portions of the spacers, each of the spacers having a second shoulder that abuts a face of the tubular portion when the second end portion is received in one of the apertures of the tubular portion.
18. The variable-nozzle turbine of claim 12 , wherein the retainer ring has an axially facing surface that engages an opposing axially facing surface of the nozzle ring along a full 360° circumference so as to substantially seal an interface between the retainer ring and the nozzle ring.
19. The variable-nozzle turbine of claim 12 , wherein the nozzle ring includes a radially outer surface facing a radially inner surface of the retainer ring, and wherein a radial gap is defined between the radially outer surface of the nozzle ring and the radially inner surface of the retainer ring, the radial gap allowing radial displacement of the nozzle ring relative to the retainer ring.