Abstract: A control ring in sliding contact with the radially outer ends of fluid displacing vanes on a pump rotor, is angularly adjustable about a pivot formation in a pump housing on one radial side of the rotor opposite a limited sealing surface on the housing having a center of curvature on the rotor axis. A sealing element pivotally mounted on the control ring is biased into wiping contact with the sealing surface to divide the pump housing into inlet and outlet pressure chambers.

Abstract: In a sliding vane type of rotary pump usable for power steering systems a seal of hour glass shape is provided between the flow directing plate, on the outlet side of the vane rotor and the outlet pressure chamber, to confine exposure of the high pressure of the outlet chamber to the downstream side of the plate within a predetermined area only partially balanced by exposure of the upstream side to such high pressure and to also isolate suction passages from the outlet chamber pressure. The result is a flexing of the flow directing plate at the center toward the pump rotor to reduce rotary clearance and permit the use of thinner and lighter weight flow directing plates.

Abstract: A fluid pressure zone is established within the piston bore of a top-loading type of radial piston pump, in opposing relation to the intake passage intersecting the bore to take up radial clearance between the piston and a sealing surface portion of the bore between the intake passage and the pressure chamber into which fluid is displaced by the piston.

Abstract: The intake fitting of a vehicle engine driven pump mounted on the engine block is connected to one end of an elongated, flexible conduit section acting as a fluid storing reservoir. The other open end of the conduit remote from the pump is anchored at a location in the engine compartment of a vehicle above the pump and readily accessible for servicing and oil level monitoring. A removable cap closes the open end of the conduit section.

Abstract: In the manufacture of vane type pumps, particularly for booster steering systems, precision assembly between the flow directing plate, sometimes referred to as a cheek plate, control plate, etc., and the cam ring is provided economically by die casting either or both components and effecting a pair of die cast tapering flat sided locating bores. One bore is elongated to allow for inaccuracies while the other is box-like in cross section. Locator pins secured in reamed bores are force fitted into the cast bores wherein the box-like bore which is dimensioned to fit a pin determines the rotational center of the components with respect to each other for exact relative positioning. The position is fixed by a pin in the elongated bore which pin can be accommodated in the elongation to compensate for spacing errors of the bores.

Abstract: The output pressure of a piston pump is limited by opening of a pressure responsive limiting valve discharging pump fluid in jet form through an injector into the inflow stream in the suction intake conduit to the pump. The jet is discharged in a direction opposite to the inflow stream to reduce inflow pressure for pump pressure control purposes.