Patent ID: 7445161

Claim:
A thermostat device comprising: a first valve disc for opening and closing a first fluid channel; a second valve disc for opening and closing a second fluid channel; and an operating member which operates in accordance with a temperature change of a fluid and in conjunction with the first and second valve discs to move integrally such that one of the first fluid channel and second fluid channel is opened and the other one of the first fluid channel and second fluid channel is closed, wherein said operating member has a case which seals in one end side thereof a thermal expansion body having a property of expanding and contracting in accordance with a temperature change and a piston retained through an opening of the other end side thereof in a freely reciprocable manner, a cylindrical portion for retaining one end of the case constituting said operating member in a freely slidable manner is provided to a main frame of the thermostat device, an opening to be opened and closed at one end of said case is provided to a part of said cylindrical portion, and one end of said case is made to be said second valve disc.