US 4,536,133 AGranted

Regulatable vane pump

AssigneeZahnradfabrik Friedrichshafen AG

InventorGunther Seidl

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Abstract

A regulatable vane pump is provided with regulating apparatus incorporated in the pump having a differential pressure piston operable responsive to booster steering flow demand wherein the piston carries a flexible leaf spring having a flat surface which serves as a shut off member against ports in a restrictor member. Actuation of the regulating piston carries the leaf spring toward the ported member to progressively shut off restrictor ports in the face of the ported member, either partially or fully depending upon the ported arrangement. As ports are gradually closed off regulation of the pump discharge is effected at various demand pressures after linear rise of rate of discharge up to a regulating point. Thereafter, there is wide separation of characteristics of regulating curves or lines for differing pressure demands. The overall effect produces a precise regulation within narrow limits as well as an economy of manufacture.

Claims12

Dependent claims

In a displacement vane pump flow regulator device for a hydraulic power system wherein a pump has a housing with outlet pressure chamber (6) to communicate with a differential pressure actuated regulating piston (16);

including flow restrictor means (12,24) having restrictor passage means (14, 15, 15') for pump pressure flow to a hydraulic power system;
means (22, 23) whereby outlet chamber pressure actuation of said regulator piston permits pressure flow from said outlet pressure chamber to a pump suction return line and means (19, 20) whereby pressure in said hydraulic power system effects piston actuation to shut-off said latter flow;
the improvement wherein said restrictor passage means comprises at least one restrictor bore normally open to communicate said pump pressure chamber to said hydraulic power system;
said flow restrictor means comprising closure means (24, 25) operated by said regulator piston to progressively at least partially shut off flow through said restrictor bore when said regulator piston is pressure actuated by pressure from said outlet pressure chamber, wherein said closure means comprises a closure member (25) disposed to move across the flow area of said restrictor bore with movement of said regulator piston in progressively restricting flow through said area;
wherein said closure means and said restrictor bore coact to effect flexibility of closure engagement;
said bore having an open port in a plane intersecting the axis of said regulator piston and wherein said closure means comprises a member slidable across and flexibly biased against said port.

3 more elements

including flow restrictor means (12, 24) having restrictor passage means (14, 15, 15') for pump pressure flow to a hydraulic power system;
means (22, 23) whereby outlet chamber pressure actuation of said regulator piston permits pressure flow from said outlet pressure chamber to a pump suction return line and means (19, 20) whereby pressure in said hydraulic power system effects piston actuation to shut-off said latter flow;
the improvement wherein said restrictor passage means comprises at least one restrictor bore normally open to communicate said pump pressure chaber to said hydraulic power system;
said flow restrictor means comprises closure means (24, 25) operated by said regulator piston to progressively at least partially shut off flow through said restrictor bore when said regulator piston is pressure actuated by pressure from said outlet pressure chamber, wherein said closure means comprises a closure member (25) disposed to move across the flow area of said restrictor bore with movement of said regulator piston in progressively restriction flow through said area;
said pump having a wall and said restrictor passage means comprising at least one restrictor bore therethrough and effecting a port over the planar area of which said closure member flexible sweeps biasedly flexured against said wall.

2 more elements

including flow restrictor means (12, 24) having restrictor passage means (14, 15, 15') for pump pressure flow to a hydraulic power system;
means (22, 23) whereby outlet chamber pressure actuation of said regulator piston permits pressure flow from said outlet pressure chamber to a pump suction return line and means (19, 20) whereby pressure in said hydraulic power system effects piston actuation to shut-off said latter flow;
the improvement wherein said restrictor passage means comprises at least one restrictor bore normally open to communicate said pump pressure chamber to said hydraulic power system;
said flow restrictor means comprising closure means (24, 25) operated by said regulator piston to progressively at least partially shut off flow through said restrictor bore when said regulator piston is pressure actuated by pressure from said outlet pressure chamber, wherein said closure means comprises a closure member (25) disposed to move across the flow area of said restrictor bore with movement of said regulator piston in progressively restricting flow through said area;
wherein said closure means comprises a leaf spring (24) carried by said regulator piston and having a flat surface (25) disposed to be slidable across said port with movement of said piston;
guide means (26, 27) in said housing slidably engageable by said leaf spring to maintain alignment thereof with said port.

3 more elements

Dependencies are inferred from the claim text.