Patent ID: 8348601

Claim:
A variable nozzle mechanism for changing a flow speed of fluid into a turbine rotor by rotating nozzles to change a nozzle-blade angle, comprising: a drive ring that is supported by a mount secured to a bearing housing configured to support the turbine rotor and that rotates relative to the mount while some inner circumferential surfaces abut against a portion of an outer circumferential surface of the mount, wherein a plurality of notches in a circumferential direction are provided at an inner rim of the drive ring, among the inner circumferential surfaces located between the notches, when a driving force for rotating the drive ring is applied, an inner diameter in a region where a contact load with the outer circumferential surface tends to become large is made larger than an inner diameter of other inner circumferential surfaces, the inner circumferential surface of the region where the contact load tends to become large does not abut against the outer circumferential surface, and a protruding portion that abuts against a head portion of a stopper pin for preventing the drive ring from dropping off from the mount is provided in the region where the contact load with the outer circumferential surface tends to become large.