Variable nozzle device, turbine, and turbocharger

Abstract

A variable nozzle devicefor a variable geometry turbocharger includes: a nozzle mount; a nozzle platedisposed so as to face the nozzle mount, the nozzle plate forming a nozzle flow passagehaving an annular shape between the nozzle plateand the nozzle mount; and a plurality of variable nozzle vanesdisposed at a predetermined interval in a circumferential direction of the nozzle flow passageso as to be individually rotatable about a pivot axis O. The nozzle plateincludes a first surfacefacing the nozzle mount, a second surfaceopposite to the first surface, and at least one through holeformed through the first surfaceand the second surface. The at least one through holehas a first openingformed on the first surfaceat an inner side of the pivot axis with respect to a radial direction, and a second openingformed on the second surfaceat an outer side of the first openingwith respect to the radial direction or at the same position as the first openingwith respect to the radial direction. Accordingly, as the working fluid 'g' injected from the through holejoins the working fluid G flowing through the nozzle flow passagetoward the turbine wheelthrough the plurality of variable nozzle vanes, the flow of the working fluid G is guided toward the inner surface at the hubside, and thereby it is possible to suppress deviation of flow of the working fluid G toward the shroud, that is, suppress the drift of the working fluid G.