Patent ID: 8806867

Claim:
A variable geometry exhaust turbocharger, comprising: a turbine housing to which exhaust gas from an internal combustion engine is introduced; a turbine rotor which is arranged in the turbine housing and is rotated by the exhaust gas; a turbine shaft whose one end is inserted in the turbine housing and is attached to the turbine rotor; a bearing which supports the turbine shaft; a bearing housing which is connected to the turbine housing and houses the bearing; and a variable nozzle mechanism which is fixed to the bearing housing and adjusts a flow of the exhaust gas to the turbine rotor, wherein the variable nozzle mechanism includes a nozzle, a nozzle mount which supports the nozzle, a lever plate which engages with the nozzle and a drive ring which engages with the lever plate, the turbine housing is a double cylindrical structure having an inner cylindrical portion and an outer cylindrical portion, a nozzle plate of an annular shape which comes in contact with a tip of the nozzle is provided in the inner cylindrical portion of the turbine housing, a through-hole and a screw through-hole are respectively provided in the nozzle mount and the nozzle plate, a sleeve member is arranged coaxially with the through-hole and the screw through-hole between the nozzle mount and the nozzle plate, the nozzle mount and the nozzle plate are connected by a fastening bolt which is inserted in the through-hole, the sleeve member and the screw through-hole in this order, the sleeve member is formed such that a portion which is in contact with the nozzle mount and the nozzle plate has a thickness greater than that of a middle portion, and the nozzle plate has a rib formed on a surface of the nozzle plate on a downstream side of the turbocharger.