Hydraulic system
AssigneeCNH Industrial America LLC
InventorThomas Johnson
Life of this patent
Estimating the term…
Abstract
A hydraulic system is provided, the hydraulic system including a hydraulic load defining a first chamber and a second chamber. Additionally, the hydraulic system includes a pressure source, a fluid storage vessel, a load sense line, and a spool valve. The spool valve fluidly connects the fluid storage vessel to one of the first or second chambers and fluidly connects the pressure source to the other of the first or second chambers. A bypass line is also provided defining a flow path between the hydraulic load and the fluid storage vessel that bypasses the spool valve. Fluid flow may encounter less resistance through the bypass line, such that the hydraulic system may run more efficiently and with a reduced risk for cavitation in the hydraulic load.
Claims20
A hydraulic system comprising:
- a hydraulic load defining a first chamber and a second chamber, the first chamber defining a first chamber pressure;
- a load sense line defining a load sense pressure;
- a pressure source configured to provide pressurized fluid to one of the first or second chambers of the hydraulic load;
- a fluid storage vessel defining a tank pressure configured to receive fluid from one of the first or second chambers of the hydraulic load;
- a control valve configured to fluidly connect the fluid storage vessel to one of the first or second chambers and the pressure source to the other of the first or second chambers;
- a bypass line defining a flow path between the first chamber of the hydraulic load and the fluid storage vessel that bypasses the control valve, the bypass line configured to selectively allow a fluid flow between the first chamber and the fluid storage vessel;
- and
- a BAC valve positioned in fluid communication with the bypass line and moveable between an open position and a closed position, the BAC valve comprising:
- a tank channel in fluid communication with the fluid storage vessel;
- a load sense channel in fluid communication with the load sense line;
- and
- a work port channel in fluid communication with first chamber of the hydraulic load, wherein when a difference between the tank pressure and the first chamber pressure exceeds a predetermined threshold, the BAC valve is configured to move to the open position to allow a fluid flow from the fluid tank channel to the load sense channel to increase the load sense pressure.
A valve for a hydraulic system including a hydraulic load, a fluid storage vessel, a pressure source, a control valve, and a bypass line, the valve positioned in fluid communication with the bypass line and comprising:
- a work port channel defining a work port channel pressure and configured for fluid connection with one of a first or second chamber of the hydraulic load;
- a load sense channel defining a load sense channel pressure and configured for fluid connection with a load sense line;
- a tank channel defining a tank channel pressure and configured for fluid connection with the fluid storage vessel of the hydraulic system;
- a first passage fluidly connecting the load sense channel and the tank channel when the tank channel pressure is a predetermined amount greater than the load sense channel pressure;
- and
- a second passage fluidly connecting the work port channel and the tank channel when the load sense channel pressure is a predetermined amount greater than the work port channel pressure.
Dependencies are inferred from the claim text.