Variable geometry turbine

A nozzle ring for a variable geometry turbine, the nozzle ring comprising:

• a generally annular wall;
• an inner flange that is generally perpendicular to the generally annular wall, and which extends from a radially inner edge of the generally annular wall;
• an outer flange that is generally perpendicular to the generally annular wall, and which extends from a radially outer edge of the generally annular wall;
• and
• two protrusions extending from one of the inner or outer flange towards the other one of the inner or outer flange, at least one of the two protrusions extending only partially towards the other one of the inner or outer flange;
• wherein the two protrusions define a first gap therebetween;
• wherein the generally annular wall and the two protrusions define a second gap between the generally annular wall and both of the two protrusions;
• and
• wherein the two protrusions are such that the first gap is tapered so that a dimension of the gap is smaller at a distal end of the protrusions and larger proximate to the inner or outer flange from which the two protrusions extend.

A support for a nozzle ring, the support comprising:

• a body, the body comprising:
• an elongate portion;
• and
• an arcuate head portion disposed adjacent one end of the elongate portion, the head portion extending generally perpendicular to an axis of the elongate portion;
• wherein the arcuate head portion defines a two opposed curved surfaces and wherein at least one of the two opposed curved surfaces defines one or more protrusions therefrom;
• and
• wherein a portion of the body proximate the arcuate head portion is generally cylindrical.

A kit of parts comprising:

• a nozzle ring for a variable geometry turbine, the nozzle ring comprising:
• a generally annular wall;
• an inner flange that is generally perpendicular to the generally annular wall, and which extends from a radially inner edge of the generally annular wall;
• an outer flange that is generally perpendicular to the generally annular wall, and which extends from a radially outer edge of the generally annular wall;
• and
• two protrusions extending from one of the inner or outer flange towards the other one of the inner or outer flange, at least one of the two protrusions extending only partially towards the other one of the inner or outer flange;
• wherein the two protrusions define a first gap therebetween;
• and
• wherein the generally annular wall and the two protrusions define a second gap between the generally annular wall and both of the two protrusions;
• and
• at least one support for a nozzle ring, the support comprising:
• a body, the body comprising:
• an elongate portion;
• and
• an arcuate head portion disposed adjacent one end of the elongate portion, the head portion extending generally perpendicular to an axis of the elongate portion;
• wherein an external axial dimension of the arcuate head portion of the at least one support generally matches an internal axial dimension of the second gap;
• wherein the nozzle ring and the at least one support are configured such that the arcuate head portion of the at least one support is receivable in the second gap and a portion of the at least one support is disposed in the first gap;
• and
• wherein the nozzle ring and the or each support are arranged such that when the arcuate head portion of the at least one support is received in the second gap and a portion of the at least one support is disposed in the first gap there is an angular clearance between the nozzle ring and the or each support, the angular clearance being localized and defined by two portions of the nozzle ring and wherein a line that connects said two portions of the nozzle ring passes through, or is proximate to an axis of the elongate portion.

An assembly comprising:

• a nozzle ring for a variable geometry turbine, the nozzle ring comprising:
• a generally annular wall;
• an inner flange that is generally perpendicular to the generally annular wall, and which extends from a radially inner edge of the generally annular wall;
• an outer flange that is generally perpendicular to the generally annular wall, and which extends from a radially outer edge of the generally annular wall;
• and
• two protrusions extending from one of the inner or outer flange towards the other one of the inner or outer flange, at least one of the two protrusions extending only partially towards the other one of the inner or outer flange;
• wherein the two protrusions define a first gap therebetween;
• and
• wherein the generally annular wall and the two protrusions define a second gap between the generally annular wall and both of the two protrusions;
• and
• at least one support for a nozzle ring, the support comprising:
• a body, the body comprising:
• an elongate portion;
• and
• an arcuate head portion disposed adjacent one end of the elongate portion, the head portion extending generally perpendicular to an axis of the elongate portion;
• wherein an external axial dimension of the arcuate head portion of the at least one support generally matches an internal axial dimension of the second gap;
• wherein the arcuate head portion of the at least one support is received in the second gap and a portion of the at least one support is disposed in the first gap;
• and
• wherein the nozzle ring and the or each support are arranged such that there is an angular clearance between the nozzle ring and the or each support, the angular clearance being localized and defined by two portions of the nozzle ring and wherein a line that connects said two portions of the nozzle ring passes through, or is proximate to an axis of the elongate portion.

A method of assembling a variable geometry turbine, the method comprising:

• providing a nozzle ring comprising a plurality of inlet vanes;
• providing two supports for a nozzle ring;
• engaging the two supports with the nozzle ring so as to form a nozzle ring assembly;
• coupling the two supports of the nozzle ring assembly with a first housing member such that the two supports cannot rotate freely about a main axis of the variable geometry turbine relative to the first housing member;
• providing a shroud that defines a plurality slots and which is fixed to a second housing member such that the shroud cannot rotate freely about a main axis of the variable geometry turbine relative to the second housing member;
• engaging the nozzle ring assembly with the shroud such that each of the plurality of inlet vanes is received in a respective one of the plurality of slots;
• and
• fixing the first housing member to the second housing member such that the rotation of the nozzle ring about the main axis of the variable geometry turbine is not constrained by the two supports.