A flow control valve includes a valve body having an inner circumferential surface defining a longitudinal bore to which first and second fluid passages are connected. A spool is slidably inserted into the bore to allow a flow of fluid from the first to second fluid passage. A valve regulates a flow rate of fluid flowing through the first fluid passage. A first seat surface is defined between an area in which the first fluid passage is connected to the bore and an area in which the second fluid passage is connected to the bore. When the flow of fluid from the first to second fluid passage is initiated, an area of a gap between the first seat surface and the spool on a plane taken in a transverse direction is 5%˜50%, preferably 10%˜20% of an area of an opening defined by the first seat surface.

A hydraulic system includes first and second valve assemblies connected to a common pump. The first valve assembly includes a main valve housed inside a manifold. A pressure compensator valve maintains a constant pressure drop across a variable orifice of the main valve. A pressure limiter valve is in communication with the main valve and the pressure compensator valve, and allows an actuator connected to the first valve assembly to operate independently of the second valve assembly so that fluid flow to a work port of the first valve assembly is not interrupted by operation of the second valve assembly.

A hydraulic control unit (4) includes a valve bush (12), a valve cover (15) partially closing the valve bush (12) on an end face (S1), a valve slide (13) guided in a longitudinal direction (L) within the valve bush (12), and a housing part (6). The housing part (6) includes a recess (8) matching an external contour of the valve bush (12). An intermediate plate (7) is configured to partially cover the valve cover (15). A spring (14) is arranged within the valve bush (12) and preloads the valve slide (13) in a starting position. The valve bush (12) is inserted, together with the valve cover (15), the valve slide (13), and the spring (14), into the recess (8) of the housing part (6) and jointly form a hydraulic valve (9). The valve bush (12) forms an inlet (19), and the valve cover (15) forms an outlet (31).

A refuse vehicle includes a chassis, an energy storage device, a vehicle body, an electric power take-off system, and a hydraulic component. The energy storage device is supported by the chassis and is configured to provide electrical power to a prime mover. Activation of the prime mover selectively drives the refuse vehicle. The vehicle body is supported by the chassis, and includes an on-board receptacle for storing refuse therein. The electric power take-off system is positioned on the vehicle body, and includes an electric motor configured to drive a hydraulic pump to convert electrical power received from the energy storage device into hydraulic power. An amount of electrical power at least one of received by and provided to the electric motor is limited by a controller to control an output characteristic of the hydraulic pump. The hydraulic component is in fluid communication with the hydraulic pump and configured to operate using hydraulic power from the electric power take-off system.

A valve, in particular for use as a pressure compensator or maintenance-type component (38) in hydraulically actuated hoisting devices (2), has a valve housing (54) with a control port (40), a fluid inlet (64) and a fluid outlet (66). A regulating piston (68) is longitudinally displaceably in the valve housing (54) and acts against an energy storage device (70) in the form of a compression spring, bringing the regulating piston (68) into positions forming a fluid-conveying connection between the fluid inlet (40) and the fluid outlet (66) or blocking this connection by a control pressure existing at the control port (40). A first orifice (88) in the regulating piston (68) connects the control port (40) to a receiving space (62) for the energy storage device (70) in a fluid-conveying manner. A second orifice (90) is in an intermediate part (72) in the valve housing (54). The receiving space (62) can be connected to a compensating chamber (92), which connected to the fluid outlet (66) in a fluid-conveying manner (98).

A control system for construction machinery includes a hydraulic cylinder operable by a working oil discharged from a hydraulic pump, a control valve arranged between the hydraulic pump and the hydraulic cylinder to control an operation of the hydraulic cylinder according to a position of a spool therein, the control valve having a first spool position for draining the working oil discharged from a chamber of the hydraulic cylinder to a drain tank, and a pressure compensated valve installed in a return hydraulic line through which the working oil discharged from the control valve at the first spool position is drained to the drain tank, the pressure compensated valve being configured to control a flow rate of the working oil passing through the pressure compensated valve according to a pressure difference between a front end and a rear end of the control valve.

The present disclosure relates to a load dependent flow control system for directing hydraulic fluid to a hydraulic actuator. The load dependent flow control system includes a closed-center valve device for controlling hydraulic fluid flow to the actuator. The closed-center valve device includes a valve spool and an electro-actuator that adjusts a position of the valve spool to adjust a rate of the hydraulic fluid flow supplied to the hydraulic actuator. A pressure sensor is provided for sensing a pressure of the hydraulic fluid provided to the hydraulic actuator. The system also includes an electronic controller configured to receive an operator flow command from an operator interface. The operator flow command corresponds to a base flow through the closed-center valve device. The electronic controller interfaces with the electro-actuator of the closed-center valve device and with the pressure sensor. At least when the sensed pressure is above a threshold pressure, the electronic controller uses the operator flow command and the sensed pressure to generate a pressure-modified flow command that is sent to the closed-center valve device to control flow through the closed-center valve device. The pressure-modified flow command corresponds to a pressure-modified flow through the closed-center valve device. The pressure-modified flow is less than the base flow through the closed-center valve device.

A hydraulic system includes: an operation device that outputs an operation signal corresponding to an operating amount of an operating unit; a variable displacement pump that supplies hydraulic oil to a hydraulic actuator; a control valve interposed between the actuator and pump, the control valve changing a meter-in opening area thereof, so an increase rate of the opening area increases in accordance with increase in the operation signal; a regulator that adjusts a tilting angle of the pump; an unloading valve that defines an unloading flow rate, at which the hydraulic oil is released to a tank; and a controller that, when the operation device is operated, determines a control valve required flow rate so rate is proportional to the meter-in opening area of the control valve, and controls the regulator so a discharge flow rate of the pump is a sum of the control valve and unloading flow rates.

A control valve compensation system for producing both a pre-compensated and a post-compensated load sensing hydraulic directional control valve module, wherein both configurations use the same components except for a sliding compensating component. The control valve compensation system generally includes a hydraulic directional control valve housing which is adapted to be easily-interchangeable between a load sensing pre-compensated pressure configuration and a load sensing post-compensated pressure configuration by simply removing and replacing a different compensator assembly within the housing. The compensator assembly is adapted to direct oil flow through the housing while simultaneously providing compensation for the valve function. Directional valve assemblies may be provided, with the valve assemblies functioning to provide post-compensated functions, pre-compensated functions, and mixed pre- and post-compensated functions. These directional valve functions can be re-configured in the field by simply swapping the compensator assemblies to produce the desired functionality of the end-user at that particular time.

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.