A flow control valve for a construction machine includes a boom valve block connected lo a hydraulic pump; a boom spool coupled to the boom valve block so as to be slidably moved, and switched on by the supply of pilot signal pressure in order to carry out a boom-up or boom-down operation, thereby controlling the hydraulic oil supplied from the hydraulic pump to a boom cylinder; a boom-up flow control arrangement for supplying the hydraulic oil from the hydraulic pump to the large chamber of the boom cylinder through the boom spool, when switching on the boom spool in order to carry out the boom-up operation; and a boom-down flow control arrangement for returning a part of the hydraulic oil, which returns from the large chamber of the boom cylinder, to the hydraulic tank through the boom spool only at a predetermined pressure or higher, when the boom spool is switched on in order to carry out the boom-down operation, wherein the part of the hydraulic oil, which returns from the large chamber of the boom cylinder, is directly returned to the hydraulic tank through the boom spool, and the part of the hydraulic oil, which returns from the large chamber of the boom cylinder, is made to join, as regeneration flow, the small chamber side of the boom cylinder.

An example valve includes: a pressure compensation spool configured to be subjected to a first fluid force of fluid received at a first port acting in a proximal direction; a pressure compensation spring disposed in a pressure compensation chamber and applying a biasing force on the pressure compensation spool in a distal direction; a turbine configured to rotate as fluid flows through the valve; and a flow area configured to throttle fluid flow from the first port to the pressure compensation chamber, wherein fluid in the pressure compensation chamber applies a second fluid force on the pressure compensation spool in the distal direction, such that the pressure compensation spool moves to a particular axial position based on force equilibrium between the first fluid force, the second fluid force, and the biasing force to throttle fluid flow from the pressure compensation chamber to a second port.

An example valve includes: a pressure compensation spool configured to be subjected to a first fluid force of fluid received at a first port acting in a proximal direction; a pressure compensation spring disposed in a pressure compensation chamber and applying a biasing force on the pressure compensation spool in a distal direction; a turbine configured to rotate as fluid flows through the valve; and a flow area configured to throttle fluid flow from the first port to the pressure compensation chamber, wherein fluid in the pressure compensation chamber applies a second fluid force on the pressure compensation spool in the distal direction, such that the pressure compensation spool moves to a particular axial position based on force equilibrium between the first fluid force, the second fluid force, and the biasing force to throttle fluid flow from the pressure compensation chamber to a second port.

An example valve includes a valve piston configured to block fluid flow from a first port of the valve to a second port of the valve when the valve is in a closed position; a forward flow spring applying a first biasing force on the valve piston in a distal direction; a reverse flow spring applying a second biasing force on the valve piston in a proximal direction; and a pressure setting spring applying a third biasing force on a check element in the distal direction, wherein fluid from the first port applies a fluid force on the check element in the proximal direction, and fluid from a pilot port applies a respective fluid force on the check element in the distal direction.

A hydraulic circuit for the transmissions of industrial and agricultural vehicles. The circuit comprises a feed pump driven by an internal combustion engine; a lubricating circuit; a main pressure regulator capable of bringing about a first change in the pressure of the working fluid in the circuit, this change in pressure being capable of regulation in relation to a first regulation pressure; a maximum pressure regulator for the lubrication circuit capable of bringing about a second change in pressure of the working fluid depending upon a second regulating pressure; and means for regulating regulation of the first and second regulating pressures.

A hydraulic circuit for the transmissions of industrial and agricultural vehicles. The circuit comprises a feed pump driven by an internal combustion engine; a lubricating circuit; a main pressure regulator capable of bringing about a first change in the pressure of the working fluid in the circuit, this change in pressure being capable of regulation in relation to a first regulation pressure; a maximum pressure regulator for the lubrication circuit capable of bringing about a second change in pressure of the working fluid depending upon a second regulating pressure; and means for regulating regulation of the first and second regulating pressures.

A working vehicle includes an electric storage device; a traction motor configured to propel the working vehicle and to generate electrical energy when braking; a hydraulic system including a hydraulic pump driven by a load motor, a hydraulic actuator and a control valve; and a control system. The control system is configured to determine a state of charge of the electric storage device; induce additional load on the hydraulic system by directing the load motor to drive the hydraulic pump and actuating the control valve to direct flow of hydraulic fluid to the hydraulic actuator when the state of charge is at or above a predetermined threshold.

A working vehicle includes an electric storage device; a traction motor configured to propel the working vehicle and to generate electrical energy when braking; a hydraulic system including a hydraulic pump driven by a load motor, a hydraulic actuator and a control valve; and a control system. The control system is configured to determine a state of charge of the electric storage device; induce additional load on the hydraulic system by directing the load motor to drive the hydraulic pump and actuating the control valve to direct flow of hydraulic fluid to the hydraulic actuator when the state of charge is at or above a predetermined threshold.

An object of the invention is to achieve a travel speed known in the art during travelling operation, improve energy efficiency by reducing energy loss, and obtain favorable travel operability less susceptible to effects from variations in a travel load and changes in a pump delivery pressure when travelling operation is performed through operation of a travel lever over a half stroke range or less. A variable restrictor valve 80 is disposed in parallel with a flow sensing valve 50 of an engine speed sensing valve unit 13. A travel pilot pressure is adapted to act in an opening direction of the variable restrictor valve 80. The variable restrictor valve 80 is set to have a continuously increasing opening area from a full closure to a maximum with an increasing travel pilot pressure. Travel flow control valves 6d and 6e have an opening area that allows a predetermined flow rate QT required for traveling to be obtained even when a target LS differential pressure is decreased to a second specified value Pa3 when the travel lever is fully operated. In a first half of a spool stroke, the travel flow control valves 6d and 6e have an opening area approximate to an opening area of comparative example 1.

There is provided a control module for a hydraulic system. The module comprises a tank and a plurality of valves. The tank is configured to store hydraulic fluid and is substantially cylindrical. The plurality of valves fluidly connect with the tank and are configured to control distribution of hydraulic fluid from the tank to one or more components of the system. The plurality of valves are spaced around a circumference of the tank. One or more passages fluidly connect the tank with at least one of the plurality of valves and/or a first of the plurality of valves with a second of the plurality of valves.