A valve includes a basic body, control spool, sealing ring, and control cover. The control spool is received in the basic body to be movable along a longitudinal axis. The basic body includes a counter-sealing surface, connecting channel, and tank channel having at least one first annular groove surrounding the control spool. The control cover and at least one end face of the control spool facing toward the longitudinal axis delimits, at least in part, a control space. The control cover includes a sealing surface that abuts the counter-sealing surface of the basic body. At least one of the sealing surface and the counter-sealing surface includes a sealing groove that surrounds the control space in ring-like fashion. The sealing ring is received in the sealing groove. The connecting channel opens out into the tank channel and into the sealing groove.

A stepper motor driven actuator system is provided. The system includes a stepper motor, a cam, and a gearbox system. The gearbox system operatively connects the stepper motor to the cam. The cam rotates in response to stepping of the stepper motor. The system also includes a valve having a control piston located therein. The control piston is configured to translate in response to rotation of the cam. The system further includes a rotary actuator. The rotary actuator is fluidly connected to the valve, and the rotary actuator is configured to rotate the cam in response to translation of the control piston.

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 invention relates to a valve device having a valve housing, and comprising a main piston (4) that is arranged in an axially slidable manner in a piston bore of the valve housing (2), via which a first consumer connection (A) and a second consumer connection (B) can be alternately connected to a pressure connection (P) and a tank connection (T1, T2) by way of the action of a first magnetic actuating system (6) and a second magnetic actuating system (8) and comprising two pilot pistons (14, 16). The invention is characterized in that in an actuated state of the respective pilot piston (14, 16), the main piston (4) follows the movement of said pilot piston (14, 16) due to the force ratio adjusting itself thereon, thus actuating the fluid-carrying connection between the pilot chamber (10, 12) of said pilot piston (14,16) and the assignable tank connection (T1, T2) such that pilot oil flows.

A spool valve V1 includes a valve element 11 and a cylinder 12 having a bore 12a which accommodates the valve element 11 to be movable in an axial direction. In this spool valve V1, when the valve element 11 in an initial position moves in the axial direction in relation to the cylinder 12, a supply valve port Vi formed between the valve element 11 and the cylinder 12 opens, whereby a working fluid is introduced from a hydraulic pressure source into a hydraulic chamber through the supply valve port Vi. A throttle portion O1 is provided in a fluid channel formed on the hydraulic chamber side of the supply valve port Vi. The throttle portion O1 is configured such that in a throttle valid region which extends from the initial position to a position where the amount of axial movement of the valve element 11 from the initial position becomes equal to a predetermined value, the area of the opening formed between the valve element 11 and the cylinder 12 is constant, and in a throttle invalid region where the amount of axial movement of the valve element 11 exceeds the predetermined value, the area of the opening increases. Thus, it becomes possible to restrain occurrence of oil impact within the hydraulic chamber to which the working fluid is supplied through the spool valve V1.

A valve body defines a work passage, a high-pressure channel fluidly connected to the work passage, a tank passage, and a cavity disposed between the high-pressure channel and the tank passage. The cavity fluidly connects the high-pressure channel and the tank passage. The cavity is defined at least in part by a first portion within which a relief valve threadedly engages, a second portion disposed adjacent to the high-pressure channel, and an annulus interposed between the first portion and the second portion. The annulus fluidly connects to the tank passage. A surface area of the relief valve exposed to the annulus is greater than a cross-sectional area of the high-pressure channel.

A fluid pressure control device includes a switching valve configured to operate in conjunction with the control valve by the pilot pressure led through the pilot valve to switch work of the operation check valve. The switching valve includes a pilot chamber to which the pilot pressure is led, a spool that moves in accordance with the pilot pressure of the pilot chamber, a bias member that biases the spool in the valve closing direction, a collar detachably installed in the pilot chamber, and a piston slidably inserted into the collar, the piston being configured to receive the pilot pressure on a back surface thereof and give thrust force to the spool against bias force of the bias member.

A hydraulic valve having a hollow valve body configured with a supply port and a supply port. The hollow valve body has several different internal diameters. An elongate spool is reciprocally received in the body and has a large diameter annular spool ring oriented adjacent a sensing land inside the hollow body forming a gap with a sensing land to cause a pressure drop across the gap in response to a flow of fluid from the pressure port through the gap to the control port. A servomotor reciprocally drives the spool lengthwise of the valve body against a spring force. When flow of fluid occurs in response to servomotor movement of the spool, the pressure drop across the gap combined with the spring force determines a pressure balanced location to which the spool is moved.

A valve sleeve 210 includes an input port P10, an output port P21 connected to a channel for output T2, a discharge port P30 and a lead-in port P22 which is disposed to be connected to the channel for output T2. A spool 220 is provided with a second land section 224 that blocks a portion between the spool 220 and the valve sleeve 210 at a position between the output port P21 and the lead-in port P22 when the spool 220 is located in a position for connecting the channel for input T1 and the channel for output T2 and blocking a channel leading from the channel for output T2 to the channel for discharge T3, and when the spool 220 is located in a position for connecting the channel for output T2 and the channel for discharge T3 and blocking a channel leading from the channel for input T1 to the channel for output T2.

A valve controller configured to operate on a Foundation Fieldbus Network and including a spool valve movable between at least an opening position and a closing position, and a flapper nozzle pilot valve arranged to move the spool between the opening position and the closing position.