Turbo fluid machine

A turbo fluid machine comprising:

• a rotary shaft configured to rotate in one rotational direction about an axis of the rotary shaft;
• an operating part configured to rotate together with the rotary shaft to compress and discharge a fluid;
• a housing accommodating the rotary shaft and the operating part;
• and
• a radial foil bearing supporting the rotary shaft such that the rotary shaft is rotatable relative to the housing, wherein
• the radial foil bearing includes:
• a top foil formed of an elastic thin plate and having a bearing surface that faces a peripheral surface of the rotary shaft;
• a bump foil formed of an elastic thin plate having a corrugated shape in which ridges of projections projected toward the top foil are arranged in a circumferential direction of the rotary shaft, the bump foil elastically supporting the top foil;
• and
• a bearing housing supporting the bump foil,
• the bump foil is divided into a first foil portion and a second foil portion arranged respectively on one side and on the other side in an axial direction of the rotary shaft,
• the top foil is elastically supported by both of the first foil portion and the second foil portion,
• the ridges on the first foil portion are inclined in the other rotational direction of the rotary shaft while extending from an edge of the first foil portion adjacent to the other side toward the one side in the axial direction, and
• the ridges on the second foil portion are inclined in the other rotational direction of the rotary shaft while extending from an edge of the second foil portion adjacent to the one side toward the other side in the axial direction.