Method of manufacturing casing of turbocharger and casing of turbocharger

A method of manufacturing a casing of a turbocharger,

• the casing including a turbine housing that houses a turbine rotor of the turbocharger, a bearing housing that houses a bearing that rotatably supports the turbine rotor, and a compressor housing that houses a compressor impeller of the turbocharger, the method comprising:
• a steam treatment step of subjecting at least one of the turbine housing and the bearing housing to a steam treatment to form an oxide film on the at least one of the turbine housing and the bearing housing;
• and
• an assembling step of assembling the turbine housing, the bearing housing and the compressor housing,
• wherein the steam treatment step includes:
• a turbine housing steam treatment step of subjecting the turbine housing to the steam treatment to form an oxide film on the turbine housing before assembling the turbine housing, the bearing housing and the compressor housing;
• and
• a bearing housing steam treatment step of subjecting the bearing housing to the steam treatment to form an oxide film on the bearing housing before assembling the turbine housing, the bearing housing and the compressor housing,
• wherein the method further comprising:
• a turbine housing machining step of machining the turbine housing;
• and
• a bearing housing machining step of machining the bearing housing,
• wherein
• the turbine housing machining step is performed between the turbine housing steam treatment step and the assembling step, and
• the bearing housing machining step is performed between the bearing housing steam treatment step and the assembling step,
• wherein
• the bearing housing includes:
• a bearing support portion that supports the bearing;
• a lubricating-oil inlet-side end surface in which an inlet for lubricating oil to be supplied to the bearing is formed;
• a lubricating-oil outlet-side end surface in which an outlet of the lubricating oil is formed;
• and
• a third portion that fits with the compressor housing of the turbocharger, and
• in the bearing housing machining step, an oxide film formed on at least one of the bearing support portion, the lubricating-oil inlet-side end surface, the lubricating-oil outlet-side end surface, and the third portion is removed by machining after the bearing housing steam treatment step.

A method of manufacturing a casing of a turbocharger, the casing including a turbine housing that houses a turbine rotor of the turbocharger, a bearing housing that houses a bearing that rotatably supports the turbine rotor, and a compressor housing that houses a compressor impeller of the turbocharger, the method consisting of:

• a steam treatment step of subjecting at least one of the turbine housing and the bearing housing to a steam treatment to form an oxide film on the at least one of the turbine housing and the bearing housing;
• a housing machining step of machining at least one of the turbine housing and the bearing housing;
• and
• an assembling step of assembling the turbine housing, the bearing housing and the compressor housing,
• wherein the steam treatment step is consisted of:
• a turbine housing steam treatment step of subjecting the turbine housing to the steam treatment to form an oxide film on the turbine housing before assembling the turbine housing, the bearing housing and the compressor housing;
• and
• a bearing housing steam treatment step of subjecting the bearing housing to the steam treatment to form an oxide film on the bearing housing before assembling the turbine housing, the bearing housing and the compressor housing,
• wherein the housing machining step is consisted of:
• a turbine housing machining step of machining the turbine housing;
• and
• a bearing housing machining step of machining the bearing housing, wherein
• the turbine housing steam treatment step is performed between the turbine housing machining step and the assembling step, and
• the bearing housing steam treatment step is performed between the bearing housing machining step and the assembling step,
• wherein
• no machining is performed on the turbine housing after the turbine housing steam treatment step,
• no machining is performed on the bearing housing after the bearing housing steam treatment step,
• the turbine housing includes a first portion that fits with the bearing housing, the first portion being a portion whose surface is machined in the turbine housing machining step,
• the bearing housing includes a second portion that fits with the first portion of the turbine housing, the second portion being a portion whose surface is machined in the bearing housing machining step,
• in the assembling step, the oxide film formed in the turbine housing steam treatment step exists on a machined surface of the first portion and the oxide film formed in the bearing housing steam treatment step exists on a machined surface of the second portion, and the turbine housing and the bearing housing are assembled so that the first portion of the turbine housing and the second portion of the bearing housing are fitted together,
• the thickness of the oxide film formed on the turbine housing including the first portion in the turbine housing steam treatment step is 10 to 30 μm, and
• the thickness of the oxide film formed on the bearing housing including the second tion in the bearing housing steam treatment step is 10 to 30 μm.

A method of manufacturing the casing of the turbocharger

• the casing including a turbine housing that houses a turbine rotor of the turbocharger, a bearing housing that houses a bearing that rotatably supports the turbine rotor, and a compressor housing that houses a compressor impeller of the turbocharger, the method comprising:
• a steam treatment step of subjecting at least one of the turbine housing and the bearing housing to a steam treatment to form an oxide film on the at least one of the turbine housing and the bearing housing;
• and
• an assembling step of assembling the turbine housing, the bearing housing and the compressor housing,
• wherein the steam treatment step includes:
• a turbine housing steam treatment step of subjecting the turbine housing to the steam treatment to form an oxide film on the turbine housing before assembling the turbine housing, the bearing housing and the compressor housing;
• and
• a bearing housing steam treatment step of subjecting the bearing housing to the steam treatment to form an oxide film on the bearing housing before assembling the turbine housing, the bearing housing and the compressor housing,
• wherein the method further comprises:
• a turbine housing machining step of machining the turbine housing;
• and
• a bearing housing machining step of machining the bearing housing,
• wherein
• the turbine housing steam treatment step is performed between the turbine housing machining step and the assembling step, and
• the bearing housing machining step is performed between the bearing housing steam treatment step and the assembling step,
• no machining is performed on the turbine housing after the turbine housing steam treatment step,
• the turbine housing includes a first portion that fits with the bearing housing,
• the bearing housing includes a second portion that fits with the first portion of the turbine housing,
• in the assembling step, the turbine housing and the bearing housing are assembled so that the first portion of the turbine housing and the second portion of the bearing housing are fitted together,
• the thickness of the oxide film formed on the turbine housing in the turbine housing steam treatment step is 10 to 30 μm, and
• in the bearing housing machining step, an oxide film formed on at least the second portion of the bearing housing is removed by machining after the bearing housing steam treatment step.