The vane pump assembly includes a housing with an inner wall that surrounds an open chamber. A rotor is rotatably disposed in the open chamber and has a circular shape when viewed in cross section. A first pair of vanes are received in the rotor and are operably connected with one another by a first bell crank which is pivotable about a pivot axis such that movement of one vane inwardly into the rotor causes the other vane to move outwardly out of the rotor to maintain both vanes in contact with the inner wall as the rotor rotates relative to the housing during operation of the vane pump assembly.

A pump includes a housings and a rotor capable of rotating within the housing. The rotor engages an interior surface of the housing in use, with at least two radially-inward shaped surfaces on the rotor forming respective chambers with the interior surface. In use, the chambers transport fluid from an inlet in the housing to an outlet in the housing as the rotor rotates. A seal provided between the inlet and the outlet will engage each of the shaped surfaces to prevent fluid passing from the outlet to the inlet as each shaped surface travels from the outlet to the inlet. The rotor includes a surface portion extending axially and circumferentially between respective edges of the shaped surfaces. On planes normal to an axis of rotation of the rotor, the surface portion of the rotor has a greater curvature than that of the interior surface of the housing.