Thermostat device and method for manufacturing thermostat device

7-8. (canceled)

The method for manufacturing the thermostat device of claim 14,

• wherein a deformed portion pushed out due to the expansion in diameter of the brass bushing by the applied pressure from the inside when the inner circumferential surface of the brass bushing is subjected to the finishing process is configured to escape into an annular groove formed by a step provided at a portion of the inner circumferential surface of the cylindrical guide corresponding to the tip portion on the press-fitting side in the axial direction of the brass bushing.

The method for manufacturing the thermostat device of claim 14,

• wherein a deformed portion pushed out due to the expansion in diameter of the brass bushing by the applied pressure from the inside when the inner circumferential surface of the brass bushing is subjected to the finishing process is configured to escape into an annular groove formed by a step provided at a portion of the inner circumferential surface of the cylindrical guide corresponding to the tip portion on the press-fitting side in the axial direction of the brass bushing.

(canceled)

A method for manufacturing a thermostat device having a cylindrical guide made of stainless steel, provided at an opening end of a bottomed cylindrical case made of stainless steel in which a thermal expansion body is sealed, slidably retaining a piston made of stainless steel advancing and retracting in response to the expansion and contraction of the thermal expansion body, comprising steps of:

• fitting a brass bushing, which slidably holds the piston, into the inner circumferential portion of the cylindrical guide member in a lightly press-fitted condition;
• and
• providing the brass bushing in a press-fitted state in the inner circumferential portion of the cylindrical guide by expanding the inner diameter by applying pressure from the inside by performing a precision finishing process to the inner circumferential surface of the brass bushing.