Variable nozzle unit and variable-geometry turbocharger

Patent metadata

Field	Value
Publication number	US-9618005-B2
Application number	US-201414529780-A
Country	US
Kind code	B2
Filing date	Oct 31, 2014
Priority date	May 29, 2012
Publication date	Apr 11, 2017
Grant date	Apr 11, 2017

Abstract

An annular seal flange is formed at an inner peripheral edge portion of an upstream-side seal ring. The seal flange projects in a downstream direction. When seal rings are viewed from radially inside, the seal flange of the upstream-side seal ring is designed to at least partially occlude an end gap of the downstream-side (the most downstream-side) seal ring.

First claim

What is claimed is:

1. A variable nozzle unit disposed between a turbine scroll passage and a gas discharge port inside a turbine housing of a variable-geometry turbocharger in such a way as to surround a turbine impeller, and capable of changing a passage area for an exhaust gas to be supplied to the turbine impeller side, comprising:
a nozzle ring disposed inside the turbine housing;
a shroud ring provided integrally with the nozzle ring at a position away from and opposed to the nozzle ring and including a cylindrical shroud portion placed on an inner peripheral edge side, projecting to the gas discharge port side, and being configured to occlude outer edges of a plurality of turbine blades of the turbine impeller,
the shroud portion being placed on an inside of an annular step portion formed on an inlet side of the gas discharge port inside the turbine housing, and
the shroud ring including a ring groove formed in an outer peripheral surface of the shroud portion;

a plurality of variable nozzles disposed in a circumferential direction between opposed surfaces of the nozzle ring and the shroud ring, each variable nozzle being turnable in forward and reverse directions about a shaft center in parallel with a shaft center of the turbine impeller; and
a plurality of seal rings provided in pressure-contact by their own elastic forces with an inner peripheral surface of the step portion of the turbine housing, an inner peripheral edge portion of each seal ring being fitted into the ring groove of the shroud ring and being configured to suppress leakage of the exhaust gas from the turbine scroll passage side, wherein
a seal flange projecting in a downstream direction is formed at an inner peripheral edge portion of at least one of the plurality of seal rings except the most downstream-side seal ring, and
when the plurality of seal rings are viewed from radially inside, the seal flange of the one seal ring is designed to at least partially occlude an end gap of the most downstream-side seal ring.

2. The variable nozzle unit according to claim 1 , wherein a cross-sectional shape of the one seal ring takes on an L-shape.

3. A variable-geometry turbocharger configured to supercharge air to be supplied to an engine by using energy of an exhaust gas from the engine, comprising the variable nozzle unit according to claim 1 .

4. A variable-geometry turbocharger configured to supercharge air to be supplied to an engine by using energy of an exhaust gas from the engine, comprising the variable nozzle unit according to claim 2 .

Assignees

• Ihi Corp

Inventors

• Segawa Kenichi

Classifications

• F05D2250/75

  given by its similarity to a letter, e.g. T-shaped · CPC title

• F04D29/122

  especially adapted for elastic fluid pumps · CPC title

• F02B37/24

  by using pumps or turbines with adjustable guide vanes · CPC title

• F04D27/002 Primary

  by varying geometry within the pumps, e.g. by adjusting vanes · CPC title

• F01D11/005 Primary

  Sealing means between non relatively rotating elements · CPC title