A multifunctional electro-hydraulic flow control valve and a flow control method. The control valve comprises a main valve, a proportional pilot valve, a flow sensor, a multifunctional valve controller, a control cavity pressure sensor, an oil inlet pressure sensor, an oil outlet pressure sensor, a temperature sensor and a cloud storage. The invention has the characteristics that a flow of the main valve is continuously controlled without being influenced by load change without installing a pressure compensator in the system, and meanwhile, the valve has the function of a flow sensor, has low pressure loss and wide flow control range, and realizes integration of flow detection and control; and information such as flow, power and efficiency of each part in a hydraulic system is monitored in real time based on a multifunctional controller, key operation state monitoring, service life prediction and fault positioning of the control valve are achieved.

In an electromagnetic proportional control valve system, left and right position control apparatuses 20 and 30 are disposed on the both ends of a main spool in a three position proportional control valve 10 and perform stroke control for the main spool. The left and right position control apparatus respectively comprise position feedback springs 25 and 35, pilot control valves 21 and 31, and proportional solenoids 27 and 37. The pilot spool is moved, for operative control, in response to a compression force of a position feedback spring and an electromagnetic force of the proportional solenoid. In addition, the output pressure is applied to both ends of the pilot spool so that control is performed to generate output pressure with a negative characteristic against the electromagnetic force of the proportional solenoids.

A valve assembly includes a linearly moving main slider, a pilot valve, a control oil inlet, and a control oil return. The pilot valve is designed as a 4/3 proportional directional valve, via which a first end face and an opposite second end face of the main slider can be fluidly connected selectively to the control oil inlet or the control oil return so that the main slider (20) is hydraulically movable by adjusting the pilot valve. The pilot valve is electrically adjustable depending on a target current. A position sensor is provided, with which an actual position of the main slider can be measured. A positioner is provided, with which the actual position can be regulated by adjusting the target current to a predefinable target position. The pilot valve is connected to the control oil return via a check valve. The check valve only permits fluid flow from the pilot valve toward the control oil return. The check valve is preloaded to a closed position by means of a first spring so that it opens at a predetermined opening pressure. The leakages at the pilot valve from the control oil inlet toward the check valve are designed to be so large that if the pressure at the control oil inlet exceeds the opening pressure by at least 2 bar, the opening pressure of the check valve is present immediately upstream of the check valve.

A spool is slidably located in a slide hole of a first housing. A second housing forms a servo chamber that is coaxial with the slide hole. A sleeve is slidably located in the servo chamber. A nut is fixed to a piston that is slidably fitted in the sleeve. An electric motor rotates a screw shaft screwed with the nut. The second housing includes an input port and a drain port. A first pressure chamber communicates with the input port. In a balanced state where forces applied to the sleeve from both sides are balanced, a second pressure chamber is blocked from the input port and the drain port by the piston. From the balanced state, when the piston shifts, the second pressure chamber comes into communication with the input port or the drain port.

An integral flapper and nozzle structure for a servo valve assembly whereby the flapper, orifices and nozzles are formed by sheets of metal formed into a single component.

A hydraulic control assembly includes means for holding pressure in a cylinder to inhibit boom or arm drop of a machine in the event that a hose between the cylinder and a main control valve (MCV) ruptures. The pressure holding means of the hydraulic control assembly include a hydraulic valve and a parts-in-body check assembly both configured for insertion into a valve cavity defined by a valve body. The hydraulic valve comprises a proportional piloted valve that controls pressure.

An electro hydraulic servo valve and a method of controlling pressure therein includes a first stage unit including a moveable direct drive valve, a second stage unit including a centering spring and a second stage spool valve that is fluidly connected to the moveable direct drive valve, and at least one pressure feedback fluid line fluidly connected to the first stage unit. The moveable direct drive valve selectively supplies fluid pressure to the second stage unit. Motion of the second stage unit is arrested using the centering spring and motion of the first stage unit is arrested when pressure is fed back to the first stage unit. A supply pressure or a return pressure is metered using the pressure feedback fluid line.

An electro hydraulic valve for a cam phaser, including an electromagnetic actuator assembly, and a hydraulic assembly, wherein the electromagnetic actuator assembly and the hydraulic assembly are arranged axially aligned along a longitudinal axis, wherein the hydraulic assembly includes a valve housing in which a valve piston is arranged axially movable along the longitudinal axis, wherein a plunger for positioning the valve piston along the longitudinal axis is arranged within the electromagnetic actuator assembly, and wherein the electromagnetic actuator assembly and the hydraulic assembly are connected with one another indirectly or directly, wherein the electromagnetic actuator assembly includes an actuator housing and a friction or form locking connection of the electromagnetic actuator assembly with the hydraulic assembly is provided by an ultrasonic weld between the actuator housing and the valve housing.

An electrohydraulic valve including an electromagnetic actuator assembly; and a hydraulic assembly, wherein the electromagnetic actuator assembly and the hydraulic assembly are arranged in axial alignment along a longitudinal axis, wherein the hydraulic assembly includes a valve housing in which a valve piston is arranged axially movable along the longitudinal axis, wherein the electromagnetic actuator assembly includes an actuator housing, a coil configured to generate a magnetic field and an armature that is arranged axially movable along the longitudinal axis to position the valve piston, wherein a connection is formed between the electromagnetic actuator assembly and the hydraulic assembly, wherein the actuator housing is formed by an encasement of at least the coil with a synthetic material through injection molding, wherein a circumferential annular groove is formed in which a seal element is positioned that seals the electromagnetic actuator assembly between the hydraulic assembly and the electromagnetic actuator assembly.

A servovalve comprising a motor, a motor bias mechanism, a first stage valve having a first position, a second stage valve movable with movement of the first valve, a reference member in fluid communication with the second valve, a transfer link acting between the first valve and the reference member, an eccentric drive acting between the motor and transfer link, wherein movement of the motor causes the transfer link to move the first valve, movement of the first valve causes the second valve member to move, movement of the second valve applies on the reference member a pressure differential from a load, the pressure differential on the reference member causes movement of the reference member, and movement of the reference member causes the transfer link to move the first valve back to the first position.