Compressor housing for supercharger and method for manufacturing the same

A compressor housing for a supercharger, which is configured to house an impeller with a plurality of blades, and includes an intake port that takes in air toward the impeller, and a discharge scroll chamber that is formed in a circumferential direction at an outer circumferential side of the impeller, and that guides the air discharged from the impeller to outside, comprising:

• a scroll piece including a cylindrical intake port forming section that forms the intake port, a scroll wall surface forming section that forms an air-intake side wall surface of the discharge scroll chamber, and a scroll outer circumferential section that covers an outer circumferential side of the discharge scroll chamber;
• a shroud piece including a cylindrical shroud press fitted section that is press fitted into the intake port forming section of the scroll piece, and a shroud wall surface forming section that forms an inner circumferential side wall surface of the discharge scroll chamber, and that forms a shroud surface opposing the impeller and a diffuser surface that extends from the shroud surface toward the discharge scroll chamber;
• and
• an outer circumferential annular piece including an outer circumferential annular press fitted section that is press fitted into the scroll outer circumferential section of the scroll piece, and an outer circumferential annular wall surface forming section that forms an outer circumferential side wall surface of the discharge scroll chamber,
• wherein the shroud piece includes a positioning section that makes contact in an axial direction with a contacting section of the scroll piece such that the outer circumferential annular piece and the scroll piece maintain a gap from one another in the axial direction.