Rotary hydraulic vane pump with hydraulic vane actuation

摘要

The pump (10) has a multi-vane rotor (26) operating within a cam ring (20) to pump oil to a component such as a power steering gear. The pump rotor (26) sandwiched between stationary thrust and pressure plates (18, 22) is supplied with oil from a surrounding fluid chamber through aligned intake ports (50, 60) in the two plates. Fluid chambers formed between the reciprocating vanes (40) of the rotor discharges oil into axially aligned discharge ports (52, 62) of the thrust and pressure plates (18, 22). The discharge port (52) of the thrust plate (18) is hydraulically connected to the discharge port (62) of the pressure plate (22). Pressure oil in the discharge port (62) of the pressure plate (22) feeds into a system pressure chamber outboard of the pressure plate (22). Oil in the system pressure chamber is fed back to a first side chamber (72) of the rotor (26) through at least one simple flow passage in the pressure plate (22). The first side chamber (72) is formed between inner and outer lands on the rotor (26). A second side chamber (78) is similarly formed on the opposite side of the rotor (26) and is hydraulically interconnected to the first side chamber (72) by the undervane passages (36). With the pump rotating, the undervane chambers (66) are pressurized by the supply of the pressure oil to the side chambers (72, 78) through the straight through passage in the pressure plate (22) to assure engagement of the vanes (40) with the operative surface of the cam ring (20).