Electro-hydraulic control device for variable displacement pump used for conveying lubricating oil to internal combustion engine, has switching valve against which the pressures in two specific lines are made to act by spring action

The device includes a return spring (5) and lines (11,13). The pressure in line (11) is set by a control valve (1) having active surface (17) to which force acting against spring (15) is applied. The pressures in the lines (13,14) are made to act against switching valve (2) by the spring action, and effective surfaces of lines (13,14) are dimensioned according to switching valve, such that pressure forces in working position of switching valve overcome the force of spring, and strength of magnet assembly along pressure forces is made to overcome the force of spring. The electro-hydraulic control device includes a return spring and lines. The pressure in a line (11) is set by a control valve having an active surface to which the force acting against a spring is applied. The pressure in the line (14) is indirectly regulated by the control valve. The active surface (16) of valve is engaged with the valve piston in the cylinder by adjusting the bias of the spring. The line (14) is switchably connected to line (13) by a switching valve. A magnet assembly (21) consists of two magnets arranged opposite to each other and mounted with respective single or double-acting magnet coils. The magnet coil and switching valve are connected by the additional pressure in the line (14), based on the last switching state. The pressures in the lines (13,14) are made to act against the switching valve by the spring action, and that the effective surfaces of the lines (13,14) are dimensioned according to the switching valve, such that the pressure forces in the working position of the switching valve overcome the force of the spring, and the strength of magnet assembly along the pressure forces is made to overcome the force of spring. An independent claim is included for operating method of electro-hydraulic control device. Elektrohydraulische Regeleinrichtung für eine Verstellpumpe (4) zur Förderung von Schmieröl für Verbrennungsmotoren mit einem umschaltbaren Regeldruck. Das den Regeldruck steuernde Schaltventil (2) ist mit einer doppeltwirkenden Magnetanordnung (21) ausgerüstet, die nur kurzzeitig mit elektrischen Strom beaufschlagt wird. Das Schaltventil (2) wird durch eine Feder in der Ruhelage gehalten und von dem geschalteten Druck (14) im Sinne einer hydraulischen Selbsthaltung in der Arbeitslage gehalten. Die hydraulische Selbsthaltung wird aufgehoben, wenn die Magnetanordnung das Ventil zurückstellt oder wenn die Öltemperatur einen vorgegebenen Grenzwert überschreitet.