US Patent 8205858 Electromagnetic pressure valve

An electromagnetic pressure regulating valve has a valve portion for conducting and regulating the pressure of an operating medium, such as oil, a magnet portion for actuating the valve portion for regulating the pressure of the operating medium and having a magnet housing, in which a magnet core is located that as needed exerts magnetic force on an armature, located in the magnet housing, a spring with a spring force generating a pressure activation threshold to be overcome upon regulation and located between the armature and an adjusting ball that is located in a pole piece of the magnet housing, and the spring has regions of different diameter.