An impeller that rotates about a central axis extending vertically includes a base portion and blades. The base portion spreads perpendicularly to the central axis. The blades are on an upper surface of the base portion at intervals in a circumferential direction. The base portion includes an irregular portion that is radially outward and in which irregularities are repeated in the circumferential direction. The irregular portion includes one or more first irregular regions and a second irregular region. The first irregular regions include first recesses with a same shape and first projections with a same shape, the first recesses and projections being alternately arranged one by one. The second irregular region is positioned between the first irregular regions and includes at least one among a second recess with a different shape from the first recesses and a second projection with a different shape from the first projections.

What is provided is a method of manufacturing a centrifugal rotary machine including: a fixing step S1 of fixing a return vane body having a virtual airfoil curved forward in a rotation direction of a rotation shaft as it goes inward in a radial direction and formed by a pressure surface recessed forward in the rotation direction and a negative pressure surface protruding forward in the rotation direction onto a guide flow path; and a cutting step S2 of forming a cut surface by cutting a portion including an inner radial end portion of the return vane body from the pressure surface to the negative pressure surface.

In a vacuum pump, the proportion of hole portions at a distal end (outer peripheral side/outer peripheral portion) of a stator disc is locally increased. More specifically, hole portions of substantially the same size are provided in parallel from the inner peripheral side to the outer peripheral side of the stator disc, and the number of hole portions provided in the outermost row is set to be larger than the number of hole portions provided in an inner row. Hole portions of substantially the same size are provided in parallel from the inner peripheral side to the outer peripheral side of the stator disc, and some of hole portions provided in the outermost row are integrated to be a single hole portion. T shaped hole portions are provided in the stator disc. L shaped hole portions are provided in the stator disc.

What is provided is a method of manufacturing a centrifugal rotary machine including: a fixing step S1 of fixing a return vane body having a virtual airfoil curved forward in a rotation direction of a rotation shaft as it goes inward in a radial direction and formed by a pressure surface recessed forward in the rotation direction and a negative pressure surface protruding forward in the rotation direction onto a guide flow path; and a cutting step S2 of forming a cut surface by cutting a portion including an inner radial end portion of the return vane body from the pressure surface to the negative pressure surface.

In a vacuum pump, the proportion of hole portions at a distal end (outer peripheral side/outer peripheral portion) of a stator disc is locally increased. More specifically, hole portions of substantially the same size are provided in parallel from the inner peripheral side to the outer peripheral side of the stator disc, and the number of hole portions provided in the outermost row is set to be larger than the number of hole portions provided in an inner row. Hole portions of substantially the same size are provided in parallel from the inner peripheral side to the outer peripheral side of the stator disc, and some of hole portions provided in the outermost row are integrated to be a single hole portion. T-shaped hole portions are provided in the stator disc. L-shaped hole portions are provided in the stator disc.

An impeller that rotates about a central axis extending vertically includes a base portion and blades. The base portion spreads perpendicularly to the central axis. The blades are on an upper surface of the base portion at intervals in a circumferential direction. The base portion includes an irregular portion that is radially outward and in which irregularities are repeated in the circumferential direction. The irregular portion includes one or more first irregular regions and a second irregular region. The first irregular regions include first recesses with a same shape and first projections with same shape, the first recesses and projections being alternately arranged one by one. The second irregular region is positioned between the first irregular regions and includes at least one among a second recess with a different shape from the first recesses and a second projection with a different shape from the first projections.