A hydraulic control system for linear actuation that includes an electric motor connected to a hydraulic pump and a hydraulic cylinder connected to the pump by a first flow line. A pressure transducer, a pressure control valve, and a check valve are connected to the first flow line between the pump and the cylinder and a tank is connected to the pump by a second flow line and the cylinder by a return line. A control valve is connected between the first flow line and the return line.

A hydraulic control system for linear actuation that includes an electric motor connected to a hydraulic pump and a hydraulic cylinder connected to the pump by a first flow line. A pressure transducer, a pressure control valve, and a check valve are connected to the first flow line between the pump and the cylinder and a tank is connected to the pump by a second flow line and the cylinder by a return line. A control valve is connected between the first flow line and the return line.

A hydraulic distributor includes at least one main spool configured to define a delivery branch, and a discharge branch, a feed branch and a pressure compensator configured such that a local pressure acts on a first side thereof and a maximum Load Sensing pressure acts on a second side characterizing either the working pressure of the hydraulic section, in the case in which there is only one hydraulic section, or, in the case in which there is a plurality of hydraulic sections, each one defining a respective characteristic pressure, of the maximum pressure among the characteristic pressures of the hydraulic sections. The pressure compensator is arranged such as to respectively intercept said delivery branch and said discharge branch.

A hydraulic work system can include a continuously variable displacement hydraulic pump that is powered by an engine and is in communication with a hydraulic actuator. A run-time displacement of the hydraulic pump for movement of the hydraulic actuator can be controlled based on a speed of the engine.

A pressure compensated load sense hydraulic system and method is disclosed where a first pressure compensated valve controls flow between a pump and a first function based on a highest function load; and a second pressure compensated valve controls flow between the pump and a second function based on the highest function load. First and second operator controls activate the first and second functions, respectively. When the first function is stalled and the second function is activated, the controller closes the first valve to remove the first function load from the load sense circuit and prevent flow to or from the first function. The controller can determine the first function is stalled when a timer exceeds an initialization period. When the controller closes the first valve, it can cycle the first valve between a shutoff period where the valve is closed, and a refresh period where the valve is opened.

A pressure compensated load sense hydraulic system and method is disclosed where a first pressure compensated valve controls flow between a pump and a first function based on a highest function load; and a second pressure compensated valve controls flow between the pump and a second function based on the highest function load. First and second operator controls activate the first and second functions, respectively. When the first function is stalled and the second function is activated, the controller closes the first valve to remove the first function load from the load sense circuit and prevent flow to or from the first function. The controller can determine the first function is stalled when a timer exceeds an initialization period. When the controller closes the first valve, it can cycle the first valve between a shutoff period where the valve is closed, and a refresh period where the valve is opened.

A hydraulic control system for linear actuation that provides a bypass flow during startup of a lifting command, provides a split flow between a cylinder and a reservoir once a minimum operating speed of a pump has been reached, and provides complete flow to a cylinder after the minimum operating speed of the pump has been reached. This is achieved through control of a flow control valve and a proportional flow control valve by a processor.

An example valve section includes: a valve body configured to be fluidly coupled to the source and the actuator; a spool movable in the valve body intermediate the source and the actuator; a pressure compensator valve disposed upstream from the spool and configured to regulate flow received from the source, where the valve body defines (i) a first passage disposed upstream from the spool and configured to fluidly couple the pressure compensator valve to the spool, and (ii) a second passage disposed downstream from the spool and configured to fluidly couple the spool to the actuator; and a counterbalance valve disposed in the second passage downstream from the spool, where the counterbalance valve is opened to permit flow therethrough from the actuator to the spool in response to a pilot pressure derived from the first passage when the spool is shifted from a neutral position.

An example valve section includes: a valve body configured to be fluidly coupled to the source and the actuator; a spool movable in the valve body intermediate the source and the actuator; a pressure compensator valve disposed upstream from the spool and configured to regulate flow received from the source, where the valve body defines (i) a first passage disposed upstream from the spool and configured to fluidly couple the pressure compensator valve to the spool, and (ii) a second passage disposed downstream from the spool and configured to fluidly couple the spool to the actuator; and a counterbalance valve disposed in the second passage downstream from the spool, where the counterbalance valve is opened to permit flow therethrough from the actuator to the spool in response to a pilot pressure derived from the first passage when the spool is shifted from a neutral position.

A work vehicle includes: an operation tool that is operated by an operator; and a controller that determines a target flow rate for hydraulic oil fed to a hydraulic device on a basis of the amount of operation of the operation tool. The controller calculates a bleed-off target flow rate on a basis of the flow rate of hydraulic oil fed from a hydraulic oil pump and the target flow rate for hydraulic oil fed to the hydraulic device, calculates a bleed-off throttle differential pressure on a basis of a pressure of hydraulic oil fed from the hydraulic oil pump and a pressure of hydraulic oil in a hydraulic oil tank, calculates a bleed-off target opening area on a basis of the bleed-off target flow rate and the bleed-off throttle differential pressure, and controls a hydraulic oil control valve such that the bleed-off target opening area is achieved.