Housing for turbocharger and method for manufacturing the same

A housing for a turbocharger which houses a compressor impeller, the housing comprising:

• an intake port formation part that defines an intake port configured to suck in air toward the compressor impeller;
• a shroud part that surrounds the compressor impeller in a circumferential direction and has a shroud surface facing the compressor impeller;
• a diffuser part that is formed on an outer circumferential side of the compressor impeller in the circumferential direction and forms a diffuser passage configured to allow compressed air discharged from the compressor impeller to pass therethrough;
• a scroll chamber formation part that forms a scroll chamber configured to guide the compressed air passing through the diffuser passage to outside;
• and
• a refrigerant flow path that is formed along the diffuser part in the circumferential direction, and allows a refrigerant for cooling the diffuser part to pass therethrough,
• wherein:
• the housing is dividably composed of a scroll piece including part of the scroll chamber formation part, and a shroud piece including at least part of the intake port formation part, part of the scroll chamber formation part, the diffuser part, and the shroud part and being press-fitted into an inner side of the scroll piece in a shaft direction,
• the refrigerant flow path is formed as an annular space that is defined by a first flow-path formation part of the scroll piece and a second flow-path formation part of the shroud piece, the first flow-path formation part and the second flow-path formation part being formed respectively at each opposing part of the scroll piece and the shroud piece which oppose each other,
• the first flow path formation part and the second flow path formation part are fitted with each other at an inner circumferential seal part configured to seal the refrigerant flow path on the inner circumferential side of the refrigerant flow path and at an outer circumferential seal part configured to seal the refrigerant flow path on the outer circumferential side of the refrigerant flow path,
• the inner circumferential seal part is formed by press-fitting a first press-fitting portion of the shroud piece into a first press-fitted portion of the scroll piece,
• the outer circumferential seal part is formed by press-fitting a second press-fitting portion of the shroud piece into a second press-fitted portion of the scroll piece, and
• an O-ring is not interposed between the first flow path formation part and the second flow path formation part.