Variable Displacement Pump

A variable displacement pump comprising:

• a housing defining an inlet port and a discharge port;
• a rotor driven by a drive shaft and coaxially aligned with the drive shaft;
• the rotor defining a plurality of primary ribs and a plurality of corresponding secondary ribs with an aperture and a curved surface defined between each secondary rib and each primary rib, each primary rib having a primary rib thickness and each secondary rib having a secondary rib thickness which is less than the primary rib thickness;
• a vane control ring disposed between the rotor and the housing, the vane control ring configured to move within an outer perimeter of the rotor;
• a plurality of vanes slidably disposed in the rotor, each vane in the plurality of vanes abutting the vane control ring at a proximate end of each vane;
• a slider ring pivotally affixed to the housing via a pivot, the slider ring defining a displacement control region with a first portion of the housing, the slider ring cooperating with the vane control ring, the rotor and the plurality of vanes form a plurality of pumping chambers that are successively connected to the inlet and discharge ports;
• a biasing means acting on the slider ring and urging the slider ring in a first direction via a first force;
• and
• a regulator valve configured to generate a varying input working fluid pressure via an input working fluid flow to the displacement control region thereby generating a second force on the slider ring about the pivot means in a second direction opposite to the first direction, the second force configured to vary relative to the first force so as vary the volume of each pumping chamber while the rotor rotates via the drive shaft.