Hydraulic Radial-piston Pump for Wind Turbines

Abstract

A hydraulic radial-piston pump transfers the wind energy of the rotor to an adjustable hydraulic motor on ground level, driving an electric generator with constant speed. The pump consists of piston assemblies, located in radial direction between camshaft and housing, supported by spherical bearings at the housing and cylindrical bearings at the camshaft, allowing for self-adjustment of the assemblies. The radial and axial bearings of the camshaft are pivotally mounted allowing for self-adjustment to the housing. At least two planes with cams opposing each other compensate the piston forces in radial direction. Preferably, the pump has four planes symmetrically arranged around a plane between the second and third plane, compensating the piston forces in axial direction. The center of gravity of the rotor is located between or near the bearings of the camshaft. The loads are supported by hydraulic pressure fields, minimizing frictional losses and increasing longevity.

What claimed is: 
     
         1 . A radial-piston pump comprising:
 a housing with at least two radial bearings spaced in axial direction,   a centrally located camshaft rotatable mounted in the radial bearings having at least one cam,   at least one piston assembly for each cam having a centerline perpendicular to the centerline of the camshaft, comprising a cylinder valve joint having a spherical face and mounted in the bore of the housing, a cylinder with a piston bore and a spherical face opposing the piston bore cooperating with the spherical face of the cylinder valve joint, and a piston, reciprocally mounted in the piston bore having a cylindrical face with a centerline perpendicular to the centerline of the piston cooperating with the cylindrical cam of the camshaft providing piston force for reciprocating the piston,   said cylinder valve joint comprising two check valves having a ring shaped outer valve plate with a face, an inner valve plate with a face and a valve body, having an outer ring shaped valve port and an inner valve port with opposing faces concentric to and in fluid communication with each other for delivering and receiving fluid to and from the piston bore,   said outer valve plate and said inner valve plate each having a spring and being moveable in axial direction for engaging the face of the outer valve plate with said face of the outer valve port and the face of the inner valve plate with said face of the inner valve port,   
     
     
         2 . A radial-piston pump comprising:
 a housing with at least two radial bearings spaced in axial direction, a centrally located camshaft rotatable mounted in the radial bearings having at least one cam, at least one piston assembly for each cam having a centerline in a plane perpendicular to the centerline of the camshaft,   wherein said radial bearings have an inner bearing face for engaging the camshaft and an outer spherical face for mounting the bearings tiltable in bores of the housing, approximating the size and shape of the outer bearing face, allowing the bearings to adjust to misalignments and deflections of the camshaft.   
     
     
         3 . A radial piston pump as defined in  claim 2 . wherein the inner and outer bearing faces are exposed to a recessed area for pressurized fluid providing hydraulic forces for reducing mechanical contact forces between camshaft and radial bearings and radial bearings and housing for improving efficiency and adjustment to compensate for misalignment and deflection. 
     
     
         4 . A radial-piston pump comprising:
 a housing with at least two radial bearings and at least one axial bearing spaced in axial direction,   a centrally located camshaft rotatable mounted in the radial bearings and to the axial bearing,   at least one piston assembly for each cam having a centerline in a plane perpendicular to the centerline of the camshaft,   wherein said axial bearing has an inner bearing face for engaging the axial face of the camshaft and an outer spherical face for mounting the bearing tilt able to an indentation of the housing approximating the size and shape of the outer bearing face, allowing the axial bearing to adjust to misalignments and deflections.   
     
     
         5 . A radial piston pump as defined in  claim 4 . wherein the inner and outer bearing faces are exposed to a recessed, sealed area for pressurized fluid providing hydraulic forces for reducing mechanical contact forces between camshaft and axial bearing and axial bearing and housing for improving efficiency and adjustment to compensate for misalignment and deflection. 
     
     
         6 . A radial-piston pump comprising:
 a housing with at least two radial bearings spaced in axial direction,   a centrally located camshaft rotatable mounted in the radial bearings having four cams with centerlines in the plane of, parallel to and an equal number of cams concentric to each other on either side of the centerline of the camshaft,   the cams being symmetrically arranged to a first plane perpendicular to the centerline of the camshaft with an equal number of cams on either side, at least one piston assembly for each cam having a centerline in a plane perpendicular to the centerline of the camshaft, cooperating with the cam of the camshaft providing piston force for reciprocating the piston,   said piston forces compensate each other in the plane of the centerline of the camshaft and balancing each other at said first plane perpendicular to the centerline of the camshaft, eliminating tilting of the camshaft and the effect of piston forces at the radial bearings.   
     
     
         7 . A radial piston pump as defined in  claim 6 , wherein a centrally located camshaft rotatable mounted in the radial bearings having three cams with centerlines in the plane of and parallel to the centerline of the camshaft, and two outer cams concentric to each other opposing the inner cam,
 at least one piston assembly for each cam having a centerline in a plane perpendicular to the centerline of the camshaft, cooperating with the cam of the camshaft providing piston force for reciprocating the piston,   a first piston assembly having twice the piston face area of a second piston assembly,   said first piston assembly cooperates with said inner cam and said second piston assemblies cooperate with said outer cams,   said piston forces compensate each other in the plane of the centerline of the camshaft and balancing each other at the plane of said first piston assembly perpendicular to the plane of the centerline of the camshaft, eliminating tilting of the camshaft and the effects of piston forces at the radial bearings .   
     
     
         8 . A radial-piston pump comprising:
 a housing with at least two radial bearings and at least one axial bearing spaced in axial direction,   a centrally located camshaft rotatable mounted in the radial bearings and to the axial bearing having at least one cam,   a coaxially mounted rotor for driving the camshaft ,   said rotor having a center of gravity acting near or between said radial bearings,   said rotor having fluid flow forces in axial direction being supported by the axial bearing of the camshaft.