Lisec, T.T.LisecQuenzer, H.J.H.J.QuenzerWagner, B.B.Wagner2022-03-082022-03-081997https://publica.fraunhofer.de/handle/publica/303666This invention relates to a microvalve which is applied in particular as a pilot valve in pneumatic control systems. Solenoid valves previously used in this field can only be miniaturized with considerable increases in costs. The microvalve according to the invention consists of a first pressure-side part (1) comprising a diaphragm structure (3) acting as a movable closing body and a second part (2) comprising an outlet opening (7) and a valve seat (5). The diaphragm structure is provided with heating elements, so that when said heating elements are heated up, this results in the diaphragm sagging against the applied pressure. At least one of the two parts has pits of defined depth (6) which are arranged in such a way that when the valve is closed, they form cavities which are heated by the heating elements. The diaphragm can be coated with a material to support the opening functions of the valve, said material having a different thermal coefficient of linear expansion than the diaphra gm material. The described microvalve can be produced cost-effectively using semiconductor technology resources and has improved switching characteristics due to its combined thermomechanical and thermopneumatic action.de608621patent1993-4317676