An example solenoid tube of a solenoid actuator for a valve includes: (i) a cylindrical body includes: a first threaded region formed on an exterior peripheral surface of the cylindrical body, and a second threaded region formed on an interior peripheral surface of the cylindrical body; and (ii) a pole piece formed as a protrusion from the interior peripheral surface of the cylindrical body and configured to divide a hollow interior of the cylindrical body into a first chamber and a second chamber, where the pole piece defines a channel therethrough, such that the channel fluidly couples the first chamber to the second chamber, where the first chamber is configured to receive an armature of the solenoid actuator therein, and where the second chamber is configured to a component such as a sensor or a manual actuator therein.

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.

The disclosure relates to an electro-hydraulic control system for directing fluid to at least one hydraulic actuator, the system comprising at least one electronic controller; first and second pilot valves being electrically connected to the at least one electronic controller which is arranged to control the operation of the first and second pilot valves, third and fourth pilot valves being electrically connected to the at least one electronic controller which is arranged to control operation of the third and fourth pilot valves. A pilot operated main valve is configured to control fluid flow to at least one hydraulic actuator. Each of the first and second pilot valves and the third and fourth pilot valves is a fail-safe pilot valve arranged to drain a regulated outlet port to a low pressure reservoir if a spool of the fail-safe pilot valve becomes stuck in an open state.

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.

A servovalve (15) comprising a motor (16), a motor bias mechanism (20), a first stage valve member (22) adapted to be moved from a first position to a first off-null position, a second stage member (29) adapted to be moved from a first position to a second position with movement of the first valve member (22), a transfer link (34) acting between the first (22) and second (29) valve members, an eccentric drive member (35) acting between the motor (16) and the transfer link (34), the transfer link (34) and drive member (35) configured such that selective movement of the motor (16) causes the transfer link (34) to move the first valve member (22), movement of the first valve member (22) causes the second valve member (29) to move, and movement of the second valve member (29) causes the transfer link (34) to move the first valve member (22) from the first off-null position back to the null position.

A servovalve has a pilot stage having a piezoelectric element actuating a pilot stage spool valve, which pilot stage spool valve comprises an output control fluid line to a main stage.

A servo valve comprising first and second nozzles and first and second piezoelectric actuators arranged to control fluid flow through the first and second nozzles respectively. A first fluid flow path is defined between the first nozzle and the first piezoelectric actuator and a second fluid flow path is defined between the second nozzle and the second piezoelectric actuator. The first and second piezoelectric actuators are arranged such that applying a voltage to the first and second piezoelectric actuators causes a change in dimension thereof, which acts to open or restrict said first and second fluid flow paths respectively.

A servo valve includes first and second nozzles spaced apart from each other, an elongate control member positioned between the nozzles, and a solenoid assembly surrounding at least a portion of the control member. The elongate control member has a first end and an opposing second end. The control member is configured to translate in response to the solenoid assembly being energised, such that the first end is moved towards the first nozzle and the second end is moved away from the second nozzle or the first end is moved away from the first nozzle and the second end is moved towards the second nozzle.

Hydraulic systems and associated methods configured to reduce leakage past a spool valve when the system is in a neutral state. Leakage reduction is achieved by shifting the spool valve within the spool bore. The amount of shifting can be controlled by a pressure controller that sets one or pressures in the system and actively/dynamically adjusts the system to achieve a desired pressure or set of pressures by shifting the spool valve.

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.