Patent ID: 9562541
Date: 2017-02-07
CPC Classifications: F04D,F05D

Claim:
1. A scroll structure of a centrifugal compressor comprising a rotary impeller and a diffuser which is provided on an outer circumferential side of the impeller, and a scroll flow path which is formed in a spiral shape that connects to an outer circumference of the diffuser, and a diffuser outlet connected to the scroll flow path, wherein an axial cross-sectional shape of the scroll flow path has a roughly circular shape, the diffuser outlet is connected to the scroll flow path a position that is aligned with a tangential portion of the roughly circular cross section, the cross sectional shape of the scroll flow path changes such that the relative position of the diffuser outlet is aligned closer to the center of the roughly circular cross section but is not aligned with the center of the cross sectional shape, the roughly circular cross sectional shape is formed from a scroll chamber which juts out in a first axial direction relative to the position of the diffuser outlet and a shift chamber that forms a remainder of the roughly circular shape in a second axial direction opposite to the scroll chamber, and the shift chamber is at least formed on the scroll flow path of a winding end portion in a circumferential direction of a spiral when a winding angle θ in a clockwise direction is set so that a line connecting a position of a tongue portion and the circle center, in a view from an axial line direction of the rotary impeller is at a position of approximately 60 degrees as a winding angle θ of the scroll flow path, the shift chamber is formed beginning at a position approximately 180 degrees preceding the winding end portion of the scroll flow path in a circumferential direction, the dimension of the shift chamber increasing so as to reach maximum at a position of approximately 360 degrees, the dimension of the shift chamber increasing linearly or parabolically as a circumferential angle increases.