An agricultural machine includes a float cylinder interconnecting a header linkage system and a frame of the machine. A first rod side accumulator and a second rod side accumulator are both in fluid communication with a rod side fluid port of the float cylinder. A first accumulator control valve is positioned to control the first rod side accumulator, and is selectively controllable between an open position allowing fluid communication between the first rod side accumulator and the rod side fluid port of the float cylinder, and closed position blocking fluid communication between the first rod side accumulator and the rod side fluid port of the float cylinder. The system provides a slower first float response with the first accumulator control valve open, and a faster second float response with the first accumulator control valve closed.

A balancing valve includes four ports. While the pressures at a pair of balancing ports of a hydraulic balancing valve are equal, the valve maintains two other ports in a closed position. Upon a pressure differential between the balancing ports, fluid communication can occur between one of the balancing ports and either of the other ports based upon the direction of the pressure differential. A hydraulic ride control system utilizes the balancing valve together with other control valves to provide ride control functionality.

An example valve assembly includes a housing having an accumulator fluid passage configured to be fluidly coupled to an accumulator, a supply fluid cavity configured to be fluidly coupled to a source of fluid, a reservoir fluid cavity configured to be fluidly coupled to a reservoir of fluid, a head fluid cavity configured to be fluidly coupled to a head-side chamber of a hydraulic actuator, and a rod fluid cavity configured to be fluidly coupled to a rod-side chamber of the hydraulic actuator; a main spool that is axially-movable within the housing; and a balancing spool that is axially-movable within the housing based on an axial position of the main spool.

A control device for controlling a hydraulic consumer (2), such as a working cylinder, has at least one control valve (18) having a control spool (20). Control spool (20) is guided in a valve housing (22) in a longitudinally movable manner and is actuated by an electric motor (24). Electric motor (24) can be controlled by control electronics (MC), which receive input signals from a sensor device (58, 60, 62) detecting at least one operating state of the consumer (2).

A vehicle including a control valve to lift and lower a boom. The vehicle further includes a control circuit to control a speed of the boom lowering via a pressure compensator that balances a first pressure signal downstream of a control valve during the boom lowering and a second pressure signal from a hydraulic user interface so that, upon increasing of the first pressure signal during the boom lowering, the control valve progressively closes.

The electrohydrostatic actuator system according to the invention comprises a volume-variable and/or rotational-speed-variable hydro machine, which is driven by an electric motor, for providing a volume flow of a hydraulic fluid, and a main shaft which is movable by the hydraulic fluid and which has at least one first chamber, wherein the first chamber, with at least one first main hydraulic line and a first main valve, is hydraulically connected to the hydro machine via a connection line. The actuator system according to the invention further comprises a secondary shaft which is movable by the hydraulic fluid and which has at least one first chamber, wherein the first chamber, with at least one first secondary hydraulic line and a first secondary valve, is hydraulically connected to the hydro machine via a connection line. Furthermore, according to the invention, a hydraulic accumulator is hydraulically connected to the first secondary hydraulic line in the area between the first chamber of the secondary shaft and the first secondary valve.

An open center hydraulic system (100) includes a tank configured to hold hydraulic fluid, a pump configured to provide pressurized hydraulic fluid from the tank, and a shunt valve configured to adapt a first opening area between a first input port and a first output port of the shunt valve dependent on a first control signal. The first input port is coupled to the pump, and the first output port is coupled to the tank. A first actuator valve is coupled to the first input port and configured to adapt a second opening area of the first actuator valve dependent on a second control signal. A hydraulic valve control unit is configured to determine a first opening area value and a second opening area value based on user input data and a predetermined relation dependent on the user input data, sending the first control signal, indicative of the first opening area value and sending the second control signal indicative of the second opening area value.

An example valve assembly includes a housing having an accumulator fluid passage configured to be fluidly coupled to an accumulator, a supply fluid cavity configured to be fluidly coupled to a source of fluid, a reservoir fluid cavity configured to be fluidly coupled to a reservoir of fluid, a head fluid cavity configured to be fluidly coupled to a head-side chamber of a hydraulic actuator, and a rod fluid cavity configured to be fluidly coupled to a rod-side chamber of the hydraulic actuator; a main spool that is axially-movable within the housing; and a balancing spool that is axially-movable within the housing based on an axial position of the main spool.

The present disclosure is an accumulator that has an oil chamber, a first piston separating a first gas chamber from the oil chamber, a second piston separating a second gas chamber from the oil chamber, and a compressible member positioned between the second piston and a stop. The compressible member is configured to dampen motion of the second piston towards the stop.

A hydraulic system can include a hydraulic actuator including a piston rod slidably disposed within a housing having a base-side port and a rod-side port, a hydraulic pump, a hydraulic reservoir, an accumulator, a first control valve operable to selectively control flow from the pump to the base-side port and from the base-side port to the reservoir, a second control valve operable to selectively control flow from the pump to the rod-side port and from the rod-side port to the reservoir, a third control valve operable to selectively allow flow between the base-side port and the accumulator, and a controller for operating the hydraulic system and including a ride control mode in which damping is provided to the hydraulic actuator by operation of the first, second, and third control valves.