Patent attributes
In an electromagnetic valve, a valve member is slidably installed in a housing to open and close a valve hole. A moving core is slidably installed in the housing, and a coil generates a magnetomotive force to attract the moving core to one side when it is energized. The valve shaft links a motion of the moving core with a motion of the valve member. A bellows surrounds the valve shaft to form a cylindrical inner space between the valve shaft and itself. The bellows is subjected to both positive and negative pressures to extend and shrink in accordance with the motions of the valve member and the moving core. An inner volume of the inner space increasing and decreasing in accordance with extending and shrinking operations of the cylindrical bellows portion. The opening of the bellows and the valve shaft form a narrow opening passage.
