A counter pressure valve arrangement for controlling a pressure level of a hydraulic fluid in a return line from a hydraulic actuator arrangement. The counter pressure valve arrangement comprises a counter pressure valve having: a moveable valve member; a counter pressure regulating port configured for being connected to the hydraulic actuator arrangement via the return line; a tank port configured for being connected to a tank or low pressure reservoir for storing low pressure hydraulic fluid; and a pump port configured for being connected to a source of pressurised hydraulic fluid. A first position of the valve member effects fluid communication between the pump port and the counter pressure regulating port for supplying pressurised hydraulic fluid to the return line, and a second position of the valve member effects fluid communication between the counter pressure regulating port and the tank port for discharging hydraulic fluid from the return line to the tank.

A selector control that is manually operable by a user for activating or deactivating a primary control or a secondary control. The selector control may include a first state for activating the primary control and deactivating the secondary control, a second state for activating the secondary control and deactivating the primary control, and a failsafe state for deactivating both the primary control and the secondary control. The selector control may be configured to maintain the second state independent of continuous user input being applied to the selector control, and configured to maintain the first state when continuous user input is applied to the selector control. The selector control is normally biased toward the failsafe state such that the selector control automatically selects the failsafe state when the user discontinues applying the user input for maintaining the first state. The selector control has particular application for use in controlling a boom of a work vehicle.

The system is an improved valve/actuator architecture using a 4-way blocked-port architecture and area asymmetry providing numerous advantages over the conventional practice. The system uses fewer control circuits and provides for reduced component parts—it reduces hose, tubing and fitting requirements (lower cost, improved packaging, less installation labor and less leakage due to fewer connections). It also eliminates the need for a spring for static load support and other suspension control components (such as a sway bar). The system simplifies the mechanical design thereby reducing cost, aids in packaging, eliminates hysteresis losses of the spring and reduces moving mass thereby lowering response time. The system further allows regeneration of hydraulic power thereby increasing overall efficiency. The system further eliminates one half of throttling loss in a servo-valve.

A spool valve device includes: a housing with channels; a spool moving to change channel connection statuses; an electric actuator including an electric motor and linear-motion conversion mechanism, the motor rotating an output shaft by torque corresponding to a drive current supplied to the motor, the mechanism converting rotational output shaft movement into straight movement and applying thrust corresponding to the torque to the spool to change position; a biasing member applying biasing force to the spool against the actuator thrust; an angle detector detecting an motor output shaft angular position; a driving portion driving the motor by controlling drive current flow supplied to the motor based on a position command input and the angular position detected by the angle detector; and an abnormality determining portion calculating the spool position based on the detected angular position and determine presence or absence of operation spool abnormality.

The subject matter of this specification can be embodied in, among other things, a fluid valve assembly that includes a first fluid port, a second fluid port, a third fluid port, a valve spool configured to be positioned at a first position, a second position away from the first position, a third position away from the first position opposite the second valve position, the valve spool defining a first fluid duct configured to fluidly connect the first fluid port to the second fluid port in the first valve position, a second fluid duct configured to fluidly connect the first fluid port to the third fluid port in the second valve position, and a third fluid duct configured to fluidly connect the first fluid port to the second fluid port in the third valve position.

An example valve includes: a first port, a second port, and a load-sense port; a valve piston configured to block fluid flow from the first port to the second port when the valve piston is in a neutral position; a reverse flow spring applying a first biasing force on the valve piston in a proximal direction; and a pressure compensation spring disposed in a spring chamber and applying a second biasing force on the valve piston in a distal direction, wherein when pressure level of fluid at the second port is higher than pressure level of fluid at the load-sense port, fluid flows from the second port to the spring chamber and the load-sense port, and wherein when pressure level of fluid at the load-sense port is higher than pressure level of fluid at the second port, fluid of the load-sense port is provided to the spring chamber.

Systems and apparatuses include a solenoid valve including a first coil, a second coil coupled to the first coil, a banjo fitting coupled to the second coil, a spool housing coupled to the banjo fitting so that the first coil and the second coil are selectively rotatable about the spool housing, a spool received within the spool housing, and an armature received within the first coil and the second coil and including a spool actuator coupled to the spool.

An exemplary valve bank and/or modular control valve having a valve body, a valve member movable in a fluid flow of the valve body to control flow of fluid, and an onboard electronic controller that is operably mounted to the valve bank or valve body. The onboard controller is operably connected to at least one actuator of the valve, which is configured to control movement of the valve member in response to commands from the onboard controller. The onboard controller may provide diagnostics, feedback and/or control of the control valve, such as via inputs from one or more sensors that may be included in the valve. The modular control valve may be used with conventional non-intelligent valve banks to thereby impart smart diagnostics and/or feedback into the valve bank in a plug-and-play manner. A communications interface may be provided in the control valve to interface and communicate with an upper-level PLC controller.

A valve device that changes the direction of flow of a hydraulic fluid supplied to and discharged from a cylinder mechanism to actuate the cylinder mechanism, the valve device including: a control valve including a main spool axially movable between different positions; a lock valve including a plunger and a pressure chamber; and a selector valve including a selector spool operable in conjunction with the main spool to axially move between different positions, the selector spool being located adjacent to the main spool and having an axis crossing an axis of the main spool.

The subject matter of this specification can be embodied in, among other things, a method that includes controlling, by a first fluid valve, a first fluid flow to a first fluid actuator, actuating, by the first fluid actuator, an output, controlling, by a second fluid valve, a second fluid flow to a second fluid actuator, and actuating, by the second fluid actuator, the output.