A solenoid valve unit has a breathing hole extending in a radial direction through a sleeve on a side of a solenoid portion and bringing a space, which is formed between an armature and a spool when the armature is at least in a predetermined region, into communication with the outside, a first opening facing a side of a valve portion and opening to the outside, a second opening opening to the outside, and a breathing channel in a solenoid case, the breathing channel communicating at an end thereof with the first opening and communicating at an opposite end thereof with the second opening.

A solenoid valve unit has a breathing hole extending in a radial direction through a sleeve on a side of a solenoid portion and bringing a space, which is formed between an armature and a spool when the armature is at least in a predetermined region, into communication with the outside, a first opening facing a side of a valve portion and opening to the outside, a second opening opening to the outside, and a breathing channel in a solenoid case, the breathing channel communicating at an end thereof with the first opening and communicating at an opposite end thereof with the second opening.

An apparatus that includes a housing with an input port and a first output port. A piston is disposed within a bore of the housing and includes a bypass via disposed transversely within the bore and a bypass tube disposed longitudinally within the bore. The bypass tube is configured to provide a flow path from the bypass via to a second output port on the bypass tube. The piston includes a sleeve disposed concentrically around the bypass tube. An interior chamber is defined by an exterior surface of the sleeve and an interior surface of the bore of the housing. The piston is configurable between a first configuration that provides a first flow path between the input port and the first output port via the interior chamber and a second configuration that provides a second flow path between the input port and the second output port via the bypass tube.

A directional-control valve is typically comprised of a valve spool that slides linearly within a valve body. The valve body typically includes five internal ports, which are covered or exposed as the spool slides within the body. The typical five-internal-port architecture precludes certain combinations of port connectivity when the spool is in the center position. For example, when the spool is in the center position, providing connectivity between the actuator ports, while simultaneously providing fluid isolation of the supply and exhaust ports, is not directly achievable with a standard five-port architecture. This application describes three embodiments that enable the aforementioned port connectivity when the spool is in the center position.

A directional-control valve is typically comprised of a valve spool that slides linearly within a valve body. The valve body typically includes five internal ports, which are covered or exposed as the spool slides within the body. The typical five-internal-port architecture precludes certain combinations of port connectivity when the spool is in the center position. For example, when the spool is in the center position, providing connectivity between the actuator ports, while simultaneously providing fluid isolation of the supply and exhaust ports, is not directly achievable with a standard five-port architecture. This application describes three embodiments that enable the aforementioned port connectivity when the spool is in the center position.

In a sleeve, two input ports are formed as ports that receive a discharge pressure of an electromagnetic pump, and a drain port connected to a drain oil passage is formed on the same circumference as that on which the input port is formed, so as to have a smaller opening area than the input port and an output port connected to an oil passage. The axial length of the second land is set so that the input port can be closed by the second land when a signal pressure is equal to or higher than a set pressure, and that the input port and the drain port can be closed by the second land when the signal pressure is lower than the set pressure.

In a sleeve, two input ports are formed as ports that receive a discharge pressure of an electromagnetic pump, and a drain port connected to a drain oil passage is formed on the same circumference as that on which the input port is formed, so as to have a smaller opening area than the input port and an output port connected to an oil passage. The axial length of the second land is set so that the input port can be closed by the second land when a signal pressure is equal to or higher than a set pressure, and that the input port and the drain port can be closed by the second land when the signal pressure is lower than the set pressure.

In a hydraulic system which is biased to a minimum system pressure using a bias valve or other flow obstruction disposed in a tank line, there is provided in a bypass line to the bias valve an evacuating and filling valve through which the hydraulic system is first evacuatable and subsequently fillable with a hydraulic fluid. The valve closes the bypass when a differential pressure overcomes a preadjusted force of a spring element. For this purpose, the valve possesses a displaceably mounted valve body with an integrated throttle and a seal face which closes a through opening when the valve body is shifted against the bias force of the spring element due to the pressure difference.

Valve and related assemblies, systems, and methods may include a self-cleaning feature that may be configured to at least partially displace material from a portion of the valve. Such valves may be utilized in a pressure exchanger.

Exemplary control valves that may be configured as a load sense, closed-center, and/or open-center valve. The control valve may include optional individual valve force sensing to potentially allow an operator to smoothly operate devices operating on low-load work ports even when a variable displacement pump is inducing pressure to operate a device connected to a high-load work port of a separate valve or worksection in the same stack. This optional force sensing may be employed on any or all worksections associated with any valve stack, and may further be included on one or both workports for any given worksection. Each worksection may include parallel and variable paths of fluid supplied by the pump. Also, flow priority to one or more worksections or external valves in a corresponding hydraulic system is optional and can be customized using the variable flow path and a corresponding fixed restriction.