US Patent 11047256 Variable nozzle unit and turbocharger

A variable nozzle unit includes a variable nozzle vane which is disposed between a hub wall surface and a shroud wall surface and is rotatable around a rotation axis parallel to a rotation axis of a turbine impeller inside a gas flow passage. The variable nozzle vane includes a leading edge, a trailing edge, and an outer vane surface connecting the leading edge and the trailing edge and facing a radial outside of the rotation axis. A concave portion at least in a range of a leading edge side in relation to the rotation axis is formed at the hub wall surface side of the outer vane surface.