THERMOSTATIC VALVE DEVICE HAVING A PILOT VALVE

摘要

A thermostatic valve device for a coolant circulating system of an internal-combustion engine having a thermostatic working element which has a housing containing an expansion material and a working piston which is movable out of the housing in a moving-out direction. A valve disk and a valve seat forms a valve. The valve disk is connected to the housing. A restoring spring is coupled to the housing. An abutment supports the working piston such that, when the working piston moves out, the housing moves against the action of the restoring spring to lift the valve disk off the valve seat. The abutment is a thrust bearing. An idle path is between the abutment and the working piston. The idle path is bridged by a first part of the moving-out movement. A bypass connection bypasses the valve. A closing member is mounted on the working piston and closes and opens the bypass connection. The bypass connection and the closing member form a pilot valve which opens during the moving-out of the working piston for bridging the idle path. A closing spring is coupled to the closing member and loads the closing member against the moving-out direction of the working piston.