TAPERED LAND THRUST BEARING DEVICE AND TURBOCHARGER PROVIDED WITH SAID BEARING DEVICE

摘要

An object is to provide a tapered land thrust bearing device with a land surface having a substantially reduced area without changing the contour shape of the land surface even if the area of the land surface is small, and high mechanical efficiency, as well as a turbocharger provided with the bearing device. A tapered land thrust bearing device includes: a flange portion fitted onto a rotary shaft and including a first thrust portion; and a thrust member including a second thrust portion which is disposed around a through hole and which faces the first thrust portion of the flange portion. The first thrust portion or the second thrust portion includes a plurality of land surfaces each of which is parallel to a plane orthogonal to an axis of the rotary shaft, the land surfaces being disposed at intervals in a circumferential direction of the through hole, a plurality of tapered surfaces each of which is disposed between the plurality of land surfaces, joined via a step to a boundary of the land surface on one side in the circumferential direction of the through hole, and joined continuously to a boundary of the land surface on the other side in the circumferential direction of the through hole, and at least one concave portion disposed on each of the plurality of land surfaces.