Electrically actuated pressure regulating valve for an adjustable hydrostatic pump, and adjustable hydrostatic pump having a pressure regulating valve

An electroproportionally controlled differential pressure valve cartridge includes actuation and tank ports on an outer circumference, and a pump port on a face-side. A spring preloads a piston into a position that relieves pressure from the actuation port to the tank port. A current increase through an electromagnet opposite the pump port and a pressure increase at the pump port counter the spring to open a connection from the pump port to the actuation port. A concentric opening extends from the pump port to a first piston surface. A duct extends from the first piston surface to a pump chamber. A further duct extends from the pump port to a spring chamber between the pump chamber and electromagnet. In the spring chamber, pressure over a second piston surface counters pressure over the first piston surface.