US 4,386,891 A · Rotary hydraulic vane pump with undervane passages for priming

Abstract

A balanced vane type hydraulic pump has a thrust plate and a pressure plate which cooperate with a cam ring, rotor and vanes to provide a plurality of pump chambers. During pump operation, fluid trapped under the vanes flows from under the vanes at the discharge port, as the vane recedes, to under the vanes at the inlet port to assist vane extension and improve pump priming. The undervane fluid passes through grooves in both plates with the groove in the pressure plate being in communication with the discharge flow of the pump. The grooves incorporate restrictions to the undervane fluid flow between the discharge and inlet positions of the vanes with the restriction in the thrust plate permitting more fluid flow than the restriction in the pressure plate to ensure that most of the fluid will pass through the rotor under the vanes in the inlet position to assist in vane extension.

Claims2

Dependent claims

An improvement in self-priming, pressure balanced sliding vane pumps having a ported pressure plate and a ported thrust plate with passage means in each plate being axially aligned with the undervane cavities formed in the pump rotor, wherein the improvement comprises;

said passage means in the thrust plate comprising two kidney-shaped passage means each of which extend the arcuate distance of adjacent ports and said kidney-shaped passage means being joined by a pair of restricted passages of predetermined flow area for accommodating undervane flow;
and said passage means in said pressure plate comprising four kidney-shaped passages each aligned with respective ports and a pair of restricted passages joining adjacent kidney-shaped passages for flow from under the outlet port to under the inlet port in the direction of pump rotation and said restricted passages having a flow area of 15 to 23% of the restricted passages in said thrust plate to permit a small amount of fluid flow to bypass the passage means in said thrust plate.

A self-priming pressure balanced sliding vane pump comprising:

a housing;
a rotor member having a plurality of vane slots formed therein, a vane slidably disposed in each vane slot;
a cam ring surrounding said rotor and cooperating with said rotor and said vanes to form a plurality of expandable chambers which expand as the vanes move radially outward and contract as the vanes move radially inward twice during each revolution of the rotor;
a thrust plate disposed in said housing closing one axial end of said chambers and having a pair of diametrically opposed inlet ports, a pair of diametrically opposed outlet ports and a pair of kidney-shaped passage means axially aligned with the radial inner end of the vane slots, each kidney-shaped passage means extending for substantially the arcuate distance of adjacent inlet and outlet ports when viewed in the direction of pumping rotation for communicating fluid flow from cavities under the outwardly moving vanes to assist in vane extension during starting and a pair of restricted passages having a predetermined flow area connecting the kidney-shaped passage means;
a pressure plate disposed in said housing closing the other axial end of said chambers and having a pair of inlet ports axially aligned with the thrust plate inlet ports, a pair of outlet ports axially aligned with the thrust plate outlet ports, four kidney-shaped passages formed for substantially the arcuate distance of respective ones of the ports in said pressure plate and aligned with the radial inner end of the vane slots, the kidney-shaped passages aligned with the inlet ports extending through said pressure plate, and a pair of restricted passages each having 15 to 23% of the flow area of the restricted passages in said thrust plate and extending from respective kidney-shaped passages aligned with said outlet ports to respective kidney-shaped passages aligned with said inlet ports when viewed in the direction of pump rotation, said kidney-shaped passages in said pressure plate accommodating a small volume of fluid flow from cavities under the inwardly moving vanes in bypass relation with the undervane cavities of the outwardly moving vanes.

2 more elements

Dependencies are inferred from the claim text.

Rotary hydraulic vane pump with undervane passages for priming

Life of this patent

Rotary hydraulic vane pump with undervane passages for priming

Life of this patent

Abstract

Claims2