Abstract: A load sense pressure regulating system is provided. The load sense pressure regulating system can be operable between a flow regulation mode and a pressure limiting mode. When the load sense pressure control system is in the flow regulation mode, flow between a load sense inlet and a pilot vent are metered by a main poppet. The load sense pressure regulating system can also include a control valve downstream from the pilot vent that is configured to control a relief setting of a relief valve to regulate the load sense pressure within a desired operating range.

Abstract: A load sense pressure regulating system is provided. The load sense pressure regulating system can be operable between a flow regulation mode and a pressure limiting mode. When the load sense pressure control system is in the flow regulation mode, flow between a load sense inlet and a pilot vent are metered by a main poppet. The load sense pressure regulating system can also include a control valve downstream from the pilot vent that is configured to control a relief setting of a relief valve to regulate the load sense pressure within a desired operating range.

Abstract: The present disclosure provides a control valve assembly arranged between a main control valve and a hydraulic function on a mobile machine. The control valve assembly includes a fluid source, a first supply valve, a first return valve, a second supply valve, and a second return valve. The control valve assembly further includes a controller configured to determine if an actual motion parameter of the hydraulic function is different than a desired motion parameter based on the determination of a motion sensor. The controller configured to selectively move at least one of the first supply valve, the first return valve, the second supply valve, and the second return valve to adjust the actual motion parameter of the hydraulic function and compensate for a difference between the actual motion parameter and the desired motion parameter.

Abstract: A hydraulic system and method for using the same are provided. The hydraulic system includes a pump, a first actuator having a first head chamber and a first rod chamber, and a second actuator having a second head chamber and a second rod chamber. The hydraulic system further includes a first control valve and a second control valve. The second control valve to selectively provide regeneration fluid flow from the first rod chamber to the first head chamber in response to a first function command is less than a first function command limit, a second function command is greater than a second function command limit, and a second function load is greater than a second function load limit.

Abstract: A valve assembly has a flow summation node coupled to a displacement control port of the first pump. Each valve in the assembly has a variable metering orifice controlling flow from an inlet to a hydraulic actuator and has a variable source orifice conveying fluid from a supply conduit to a flow summation node. The source orifice enlarges as the metering orifice shrinks. Each valve includes a variable bypass orifice and the bypass orifices of all the control valves are connected in series forming a bypass passage between a bypass node and a tank. The bypass node is coupled to the flow summation node and receives fluid from a second pump. At each valve, a source check valve conveys fluid from the supply conduit to the inlet and a bypass supply check valve conveys fluid from the bypass passage to the inlet.

Abstract: Fluid from two pumps is allocated to a plurality of hydraulic actuators based on a plurality of flow commands, each specifying a desired amount of flow to be applied to a different hydraulic actuator. For a given hydraulic actuator, the allocation involves (1) determining an apportionment of the desired amount of flow, if no other hydraulic actuator is active, and (2) altering the apportionment in response to all the plurality of flow commands, and (3) using the altered apportionment to determine a first amount of the flow for one pump to provide and a second amount of the flow for the other pump to provide. The process is repeated for all the hydraulic actuators. Supply valves for each hydraulic actuator are controlled by the associated first and second amounts and each pump is controlled in response to either the first or second amounts for all the hydraulic actuators.

Abstract: A system has a variable displacement pump that supplies pressurized fluid to power a plurality of hydraulic functions. Each hydraulic function has a control valve with a variable source orifice controlling fluid flow between the pump and a flow summation node, and a variable metering orifice controlling fluid flow between the flow summation node and a hydraulic actuator. Variable bypass orifices in the control valves are connected in series between the flow summation node and a tank. As the metering orifice in a control valve enlarges, the source orifice enlarges and the bypass orifice shrinks. This alters pressure at the flow summation node, which is used to control the output of the pump. Components are provided to give selected hydraulic functions different levels of priority with respect to consuming fluid flow from the pump.

Abstract: A hydraulic system includes a first pump and a plurality of valves that control fluid flow from the first pump to several actuators. Variable source orifices in the control valves are connected in parallel between the first pump and a node, and variable bypass orifices in the control valves are connected in series between the node and a tank. Pressure at the node controls displacement of the first pump. Each control valve also has a metering orifice for varying fluid flow between the node and one of the actuators. A hydrostatic pump-motor, coupled between two ports of a given actuator, is driven in a motoring mode by fluid exiting one of those ports. In a pumping mode, the hydrostatic pump-motor forces lower pressure fluid exhausting from one port into the other port of the given actuator.

Abstract: A system has a variable displacement pump that supplies pressurized fluid to power a plurality of hydraulic functions. Each hydraulic function has a control valve with a variable source orifice controlling fluid flow between the pump and a flow summation node, and a variable metering orifice controlling fluid flow between the flow summation node and a hydraulic actuator. Variable bypass orifices in the control valves are connected in series between the flow summation node and a tank. As the metering orifice in a control valve enlarges, the source orifice enlarges and the bypass orifice shrinks. This alters pressure at the flow summation node, which is used to control the output of the pump. Components are provided to give selected hydraulic functions different levels of priority with respect to consuming fluid flow from the pump.

Abstract: A valve assembly has a flow summation node coupled to a displacement control port of the first pump. Each valve in the assembly has a variable metering orifice controlling flow from an inlet to a hydraulic actuator and has a variable source orifice conveying fluid from a supply conduit to a flow summation node. The source orifice enlarges as the metering orifice shrinks. Each valve includes a variable bypass orifice and the bypass orifices of all the control valves are connected in series forming a bypass passage between a bypass node and a tank. The bypass node is coupled to the flow summation node and receives fluid from a second pump. At each valve, a source check valve conveys fluid from the supply conduit to the inlet and a bypass supply check valve conveys fluid from the bypass passage to the inlet.

Abstract: A valve assembly couples a plurality of hydraulic actuators to a variable displacement pump and to a tank. A separate valve is associated with each hydraulic actuator and comprises a variable flow source orifice between the supply conduit and a summation node coupled to a pump control port, a variable metering orifice between the summation node and the associated hydraulic actuator, and a variable bypass orifice between the summation node and the tank. As a valve operates to enlarge the metering orifice, the flow source orifice also enlarges, and the bypass orifice shrinks. When the valve operates to shrink the metering orifice, the flow source orifice also shrinks and the bypass orifice enlarges. Those operations vary fluid flow in and out of the summation node, which alters pressure applied to the pump control, thereby causing the pump output to vary as required to drive the associated hydraulic actuator.

Abstract: A valve assembly couples a plurality of hydraulic actuators to a variable displacement pump and to a tank. A separate valve is associated with each hydraulic actuator and comprises a variable flow source orifice between the supply conduit and a summation node coupled to a pump control port, a variable metering orifice between the summation node and the associated hydraulic actuator, and a variable bypass orifice between the summation node and the tank. As a valve operates to enlarge the metering orifice, the flow source orifice also enlarges, and the bypass orifice shrinks. When the valve operates to shrink the metering orifice, the flow source orifice also shrinks and the bypass orifice enlarges. Those operations vary fluid flow in and out of the summation node, which alters pressure applied to the pump control, thereby causing the pump output to vary as required to drive the associated hydraulic actuator.

Abstract: Fluid from two pumps is allocated to a plurality of hydraulic actuators based on a plurality of flow commands, each specifying a desired amount of flow to be applied to a different hydraulic actuator. For a given hydraulic actuator, the allocation involves (1) determining an apportionment of the desired amount of flow, if no other hydraulic actuator is active, and (2) altering the apportionment in response to all the plurality of flow commands, and (3) using the altered apportionment to determine a first amount of the flow for one pump to provide and a second amount of the flow for the other pump to provide. The process is repeated for all the hydraulic actuators. Supply valves for each hydraulic actuator are controlled by the associated first and second amounts and each pump is controlled in response to either the first or second amounts for all the hydraulic actuators.

Abstract: A hydraulic system has a valve assembly with two workports coupled to chambers of first and second cylinders which are connected mechanically in parallel to a machine component. A separation control valve is connected between first chambers of both cylinders, and a shunt control valve is connected between the workports. A recovery control valve couples an accumulator to the first chamber of the second cylinder. Opening and closing the valves in different combinations routes fluid from one or both cylinders into the accumulator where the fluid is stored under pressure, and thereafter enables stored fluid to be used to power one or both cylinders. The shunt control valve is used to route fluid exhausting from one chamber of each cylinder to the other chambers of those cylinders. Thus the hydraulic system recovers and reuses energy in various manners.

Abstract: A method provides several modes for recovering hydraulic energy produced by an overrunning load acting on cylinders connected in parallel to a machine component. In one mode, fluid from first chambers in both cylinders is routed into the accumulator, while other fluid is directed into second chambers of those cylinders. In a different mode, fluid is routed from the first chamber of only one cylinder into the accumulator, and fluid from the first chamber of the other cylinder goes into the second chambers of both cylinders. Yet another mode comprises routing fluid from the first chambers of both cylinders into the second chambers of both cylinders. In still another mode, fluid from the first chambers of both cylinders goes into the return conduit while the second chambers of both cylinders receive fluid from a supply conduit. Several modes of reusing the recovered energy are described.

Abstract: A hydraulic system has a valve assembly with two workports coupled to chambers of first and second cylinders which are connected mechanically in parallel to a machine component. A separation control valve is connected between first chambers of both cylinders, and a shunt control valve is connected between the workports. A recovery control valve couples an accumulator to the first chamber of the second cylinder. Opening and closing the valves in different combinations routes fluid from one or both cylinders into the accumulator where the fluid is stored under pressure, and thereafter enables stored fluid to be used to power one or both cylinders. The shunt control valve is used to route fluid exhausting from one chamber of each cylinder to the other chambers of those cylinders. Thus the hydraulic system recovers and reuses energy in various manners.

Abstract: A method provides several modes for recovering hydraulic energy produced by an overrunning load acting on cylinders connected in parallel to a machine component. In one mode, fluid from first chambers in both cylinders is routed into the accumulator, while other fluid is directed into second chambers of those cylinders. In a different mode, fluid is routed from the first chamber of only one cylinder into the accumulator, and fluid from the first chamber of the other cylinder goes into the second chambers of both cylinders. Yet another mode comprises routing fluid from the first chambers of both cylinders into the second chambers of both cylinders. In still another mode, fluid from the first chambers of both cylinders goes into the return conduit while the second chambers of both cylinders receive fluid from a supply conduit. Several modes of reusing the recovered energy are described.

Abstract: A valve assembly controls fluid flow between first and second ports of a hydraulic actuator and each of a supply line and a return line. A first electrohydraulic proportional valve is connected between the supply line and the first port, and second electrohydraulic proportional valve is connected between the supply line and the second port. A first counterbalance valve couples the second port to the return line and operates in response to pressure created by the first electrohydraulic proportional valve and the first port. A second counterbalance valve couples the first port to the return line and operates in response to pressure created by the second electrohydraulic proportional valve and the second port. Thus operation of the first counterbalance valve is slaved to the first electrohydraulic proportional valve, and the second counterbalance valve is slaved to the second electrohydraulic proportional valve.

Abstract: A solenoid operated valve has a valve body with a plurality of ports and a spool slidable within the body to interconnect the ports in different combinations. A solenoid, which is coupled to drive the spool, has a coil wound on an annular bobbin with a tube of an electrically conductive, non-magnetic metal within the bobbin. A first pole piece extends into one end of the tube and a second pole piece extends into another end of the tube. A separate bushing is located in an aperture in each pole piece. Each bushing has a tubular body with a first end section that has a larger outer diameter than a second end section and the second end section that has a smaller inner diameter than the first end section. The solenoid further includes an armature that is slidably received in the bushings and engaging the spool.

Abstract: A hydraulic fluid is supplied from a tank to a plurality of actuators by a variable displacement pump which produces an output pressure that is a constant amount greater than a pressure at a control input. A mechanism senses the greatest pressure among the workports to provide a first load-dependent pressure and a second load-dependent pressure which is greater than the first load-dependent pressure when the pump operates a maximum flow capacity. Each valve section includes a pressure compensating valve which controls the fluid flow to the associated actuator in response to a pressure differential between the metering orifice and either the first or second load-dependent pressures. When the pump operates at maximum flow capacity, actuators connected to the valve sections in which the pressure compensating valve responds to the first load-dependent pressure receive the fluid flow on a priority basis as compared to the other valve sections.