Claims
- 1. A balanced variable displacement roller pump system comprising:a housing having a rotor received therein for rotation about an axis; first and second cam rings received in the housing, the cam rings being independently and selectively movable toward and away from the rotor to define first and second independently variable pumping sections; a control assembly operatively associated with the cam rings for selectively altering positions of the first and second cam rings; and a biasing member urging the cam rings away from the rotor.
- 2. The pump system of claim 1 wherein the control assembly includes first and second control pistons for independently varying the position of the cam rings relative to the rotor.
- 3. The pump system of claim 1 further comprising first and second inlets and first and second outlets to the pump housing, the control assembly selectively shutting off flow through one of the outlets in response to a predetermined condition.
- 4. The pump system of claim 3 wherein the control assembly includes a first and second control pistons for independently varying the position of the cam rings relative to the rotor, the first control piston in selective communication with one of the outlets for altering the position of the first control piston in response to a preselected condition in the outlet.
- 5. A balanced variable displacement vane pump system comprising:a housing having a rotor received therein for rotation about an axis; first and second cam rings received in the housing and selectively movable toward and away from the rotor to define first and second independent pumping sections; a control assembly operatively associated with the cam rings for selectively using the pumping sections in first and second, different modes of operation, and means for biasing the cam rings toward positions of maximum displacement.
- 6. The pump system of claim 5 and using only one pumping section during a second mode of operation.
Parent Case Info
This application claims the benefit of and hereby expressly incorporates by reference U.S. Provisional Application Serial No. 60/148,827, filed on Aug. 13, 1999.
US Referenced Citations (20)
Foreign Referenced Citations (3)
Number |
Date |
Country |
2 004 300 |
Nov 1970 |
DE |
30 01 673 |
Jan 1980 |
DE |
WO 9743518 |
Nov 1997 |
WO |
Provisional Applications (1)
|
Number |
Date |
Country |
|
60/148827 |
Aug 1999 |
US |