The invention relates to a valve, in particular a 4/2-way slide valve (60), comprising a valve piston (67), which is guided in a longitudinally movable manner in a valve housing (25), for selectively connecting and disconnecting fluid connections in the valve housing (25), such as a pressure supply connection (P), a tank connection (T), and two utility connections (A, B), and comprising a magnetic system (49), to which current can be supplied, for controlling the valve piston (67), characterized in that, when no current is supplied to the magnetic system (49), the control pressure at one of the utility connections (A, B) can be set, in particular limited, by means of a control device (62, 70, 79, 80, 88) arranged in the valve housing.

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 arrangement has two main valves which are each preloaded by a spring device into a first switching position, and which can each be switched into a second switching position by means of an assigned pilot valve. The pilot medium required for switching is provided with a pilot pressure at a pilot connection of each pilot valve. The main valves are each equipped with a working valve section each of which are fluidically connected to one another. In addition, each main valve contains a monitoring valve section. The monitoring valve sections are designed to provide the venting of at least one pilot connection when the two main valves are in different switching positions. This allows a fluid-actuated actuator to be controlled in accordance with high safety standards.

A spool assembly is disclosed for use in a valve. The spool assembly may have a cylindrical body that is hollow and has a least one radially oriented orifice that passes through a wall of the cylindrical body. The spool assembly may also have an insert slidably disposed inside the cylindrical body. The insert may have a land that axially divides a space inside the cylindrical body.

A double-loop control system with a single hydraulic motor relates to a technical field of hydraulic transmission control, including a hydraulic motor (1), a positive control loop (2), a negative control loop (3), a hydraulic pump (4), an accumulator (5), and an oil tank, wherein the hydraulic motor (1) adopts a unique thrust structure with four inlet/outlet ports; the positive control loop (2) and the negative control loop (3) independently control the hydraulic motor (1), wherein the positive control loop (2) and the negative control loop (3) drive together or only one drives; or braking kinetic energy and potential energy of loads are stored in the accumulator (5) for energy recovery. The present invention uses only one hydraulic motor for satisfying different work conditions and different load driving requirements with advantages such as simple structure, high system reliability and high energy efficiency.

Provided is a hydraulic drive device, wherein the hydraulic drive device is provided with: a cylinder (101); a rod (103); a piston (102); a hydraulic pump (107); a tank (113); a valve (106) that can be switched between a positive state of connecting the hydraulic pump (107) and a head chamber (101h) and connecting a rod chamber (101r) and the tank (113), and a negative state of connecting the hydraulic pump (107) and the rod chamber (101r) and connecting the head chamber (101h) and the tank (113); and a confluence channel (114) at which, when the valve (106) is in the positive state, at least a portion of hydraulic oil going from the rod chamber (101r) to the tank (113) is merged into hydraulic oil going from the hydraulic pump (107) to the head chamber (101h).

A combination valve built in a main valve of a solenoid valve includes: a first communication passage having a first port and a second port; a second communication passage branching from the first communication passage and having a third port; a first valve body provided in the first communication passage and configured to permit only the flow of working oil from the first port to the third port; and a second valve body provided in the first communication passage and configured to permit only the flow of working oil from the first port to the second port. The first valve body is located upstream relative to the second valve body.

A valve, in particular proportional pressure regulating valve, having a spring-loaded valve piston (10) which is guided in longitudinally displaceable fashion, in a manner actuated by an energizable actuating magnet (14), within a valve housing (12) and which, in a manner dependent on the displacement position thereof, produces or shuts off again a fluid-conducting connection between a pump port (P) and a working port (A) and between said working port (A) and a tank port (T) in the valve housing, wherein those face sides of the valve piston (10) which are situated opposite one another are permanently acted on by the pressure of the tank port (T), and wherein the valve piston (10) has a regulation surface (44) which is active in terms of pressure and which is connectable in fluid-conducting fashion to the working port (A) for the generation of the regulation pressure (P.sub.R), and having a ring-shaped chamber (42) in the valve housing (10), into which ring-shaped chamber the working port (A) opens in a radial or axial direction, characterized in that, on the valve piston (10), at the location of the transition between the ring-shaped chamber (42) and the opening-in point of the working port (A), the regulation surface (44) which is active in terms of pressure is designed such that, in the deenergized state of the actuating magnet (14), a maximum regulation pressure (P.sub.R) can be generated by virtue of a respective settled state between the force of a compression spring (30) of the spring-loaded valve piston (10) and the regulation pressure (P.sub.R) prevailing at the regulation surface (44) of the valve piston (10) taking effect.

A valve body comprises an inner compartment extending along a longitudinal axis from a second end portion towards a first end portion. First, second, and third fluid ports in to the valve body are perpendicular to the longitudinal axis. The second fluid port is between the third and the first fluid port. A fourth fluid port is parallel to the longitudinal axis. A spool is configured to selectively reciprocate in the inner compartment. The spool comprises a first fluid receptacle configured to block fluid flow to the third fluid port and to fluidly communicate with the second fluid port when the spool adjoins the first end portion. The first fluid receptacle is configured to fluidly communicate with the second fluid port and with the third fluid port when the spool adjoins the second end portion. A second fluid receptacle is configured to receive fluid pressure from the fourth fluid port.

A control device includes a valve, having a body connected to the first chamber of a cylinder via a first hydraulic connection and to the second chamber of the cylinder via a second hydraulic connection. The control device includes a first hydraulic duct connected to a first actuating-fluid source, and a second hydraulic duct connected to a second actuating-fluid source. The hydraulic ducts communicate with the body of the valve. The valve further includes a distribution device that is movable within the body of the valve, between a first position, in which the distribution device places the first hydraulic connection and the first hydraulic duct in fluid communication, and a second position, in which the distribution device places the second hydraulic connection and the second hydraulic duct in fluid communication.