Claims
- 1. An axial piston fluid pump comprising:
a housing having an inner wall surface surrounding a barrel chamber and a port surface at a first end of the barrel chamber, the port surface including a delivery port and an exhaust port circumferentially spaced apart in relation to a center axis of the barrel chamber; a barrel rotatably mounted within the barrel chamber in the housing and having a plurality of axially extending; circumferentially spaced piston bores therein, each piston bore having associated therewith a cylinder port in an end wall of the barrel located adjacent the port surface which cylinder port sequentially communicates with the delivery and exhaust ports during rotation of the barrel in the barrel chamber; a plurality of pistons disposed in the piston bores for reciprocation; and a drive shaft for rotatably driving the barrel in the barrel chamber; and wherein:
the housing includes an inlet passage for delivering low pressure fluid to a second end of the barrel chamber opposite the port surface; the barrel has a radially outer surface radially inwardly spaced from the inner wall surface of the barrel chamber to form an impeller pump chamber; at least one impeller vane projects radially outwardly from the outer wall surface of the barrel and terminates at a radially outer vane edge adjacent the inner wall surface of the barrel chamber; and the impeller pump chamber has an inlet end in fluid communication with the second end of the barrel chamber and an outlet end in fluid communication with the delivery port, whereby upon rotation of the barrel in the barrel chamber, low pressure fluid from the second end of the barrel chamber is supercharged by the impeller vane prior to passage through the delivery port.
- 2. A pump as set forth in claim 1, wherein the drive shaft passes through the center of the barrel.
- 3. A pump as set forth in claim 2, wherein the barrel is axially slidable on the shaft.
- 4. A pump as set forth in claim 3, wherein the barrel is biased against the port surface.
- 5. A pump as set forth in claim 2, wherein the drive shaft is rotatably supported in the housing by bearings at opposite ends of the housing, which bearings carry the hydraulic loading acting on the barrel.
- 6. A pump as set forth in claim 1, wherein the at least one impeller vane includes a plurality of impeller vanes circumferentially spaced around the barrel.
- 7. A pump as set forth in claim 6, wherein each vane has a helical portion and an axial portion.
- 8. A pump as set forth in claim 6, wherein none of the vanes axially overlap an adjacent vane.
- 9. A pump as set forth in claim 6, wherein each vane is helical and of progressively increasing circumferential width going from the inlet to the outlet end of the impeller pump chamber, whereby the circumferential spacing between relatively adjacent vanes progressively decreases going from the inlet to the outlet end of the impeller pump chamber.
- 10. A pump as set forth in claim 1, wherein the port surface further has an annular discharge groove at the outlet end of the impeller pump chamber for receiving supercharged fluid and directing the supercharged fluid to the delivery port.
- 11. A pump as set forth in claim 10, wherein the discharge groove is connected to the delivery port by a volute.
- 12. A pump as set forth in claim 10, wherein the discharge groove progressively increases in cross-sectional area in the direction of rotation of the barrel.
- 13. A pump as set forth in claim 1, wherein the piston barrel comprises a core including a plurality of circumferentially spaced piston bores, and a sleeve surrounding the core, the sleeve including a cylindrical hub portion, and the at least one impeller blade projecting radially outwardly from the hub portion.
- 14. A pump as set forth in claim 13, wherein the hub portion and at least one impeller blade are formed as a unitary piece.
- 15. A pump as set forth in claim 13, wherein the sleeve is molded from plastic.
- 16. A pump as set forth in claim 13, wherein the core includes a plurality of circumferentially spaced apart grooves in the radially outer surface thereof.
- 17. A pump as set forth in claim 1, wherein the vane extends about the axial length of the barrel.
- 18. In an axial piston fluid pump, a housing having a cylindrical inner wall surface surrounding a barrel chamber; a barrel mounted for rotation within the barrel chamber in the housing and having a plurality of circumferentially spaced piston bores therein; and a plurality of pistons reciprocally movable in the piston bores for pumping fluid from a delivery passage to an exhaust passage; and the barrel having at least one impeller vane projecting radially outwardly and terminating at a radially outer vane edge adjacent the inner wall surface of the barrel chamber.
- 19. A pump as set forth in claim 18, wherein the piston barrel comprises a core including the piston bores, and a sleeve surrounding the core, the sleeve including a cylindrical hub portion, and the at least one impeller blade projecting radially outwardly from the hub portion.
- 20. A pump as set forth in claim 19, wherein the hub portion and at least one impeller blade are formed as a unitary piece.
- 21. A piston barrel for an axial piston fluid pump, comprising a core including a plurality of circumferentially spaced piston bores, and a sleeve surrounding the core, the sleeve including a cylindrical hub portion and at least one impeller blade projecting radially outwardly and termination at a radially outer vane edge.
Parent Case Info
[0001] This application claims the benefit of U.S. Provisional Application No. 60/247,277 filed Nov. 10, 2000, which is hereby incorporated herein by reference in its entirety.
Provisional Applications (1)
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Number |
Date |
Country |
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60247277 |
Nov 2000 |
US |