A load sense pressure regulating system is provided. The load sense pressure regulating system can be operable between a flow regulation mode and a pressure limiting mode. When the load sense pressure control system is in the flow regulation mode, flow between a load sense inlet and a pilot vent are metered by a main poppet. The load sense pressure regulating system can also include a control valve downstream from the pilot vent that is configured to control a relief setting of a relief valve to regulate the load sense pressure within a desired operating range.

An actuator includes: a casing; a pressure reducing valve and a piston. The pressure reducing valve is provided in the casing to reduce a pressure of a driving fluid supplied from an outside of the casing to a predetermined level. The piston is provided in the casing to form a pressure chamber together with the casing. The piston is driven by the driving fluid that has been pressure-reduced to the predetermined level.

A servo valve unit capable of precisely controlling the position of a pneumatic cylinder that does not require a servo amplifier and a small sized and/or high durability servo valve unit are disclosed. The servo valve unit comprises a unit body having a first end portion and a second end portion, a first valve portion, a second valve portion, a first seal member that opens and closes the first valve portion, a second seal member that opens and closes the second valve portion, a first drive mechanism that drives the first seal member by a first electric pulse, a second seal member that drives the second seal member by a second electric pulse, a supply flow path that extends between the first end and the first valve, an exhaust flow path that extends between the second end and the second valve, a common flow path connected to the supply flow path and the exhaust flow path via the first valve portion and the second valve portion, and a drive flow path connected to the pneumatic actuator. The first drive mechanism and the second drive mechanism are arranged in a drive mechanism arrangement portion located between the first end portion and the second end portion. The drive air flow path can branch from a branch portion located between the drive mechanism arrangement portion and the first end portion and extends to the first end portion. Alternatively drive air flow path can branch from the common flow path from a branch portion located between the drive mechanism arrangement portion and the second end portion and extends to the second end portion.

A valve unit (V) has a valve housing (50) that includes a supply oil passage (55) configured to receive operating oil from a hydraulic pump, and a pressure adjustment valve (Va) configured to adjust the pressure of the supply oil passage (55). The pressure adjustment valve (Va) includes a pressure adjustment valve body (61) configured to open and close the supply oil passage (55), a compression coil spring (62) that keeps the pressure adjustment valve body (61) at a closed position when the pressure of the supply oil passage (55) is smaller than a set value and allows the pressure adjustment valve body (61) to open when the pressure of the supply oil passage (55) is not smaller than the set value, and a restriction member (63) configured to, when the pressure adjustment valve body (61) becomes open against the urging force of the spring (62) in response to a pressure of the operating oil, abut against the pressure adjustment valve body (61) to restrict movement of the pressure adjustment valve body (61).

Twin poppet mechanism (100) of a valve positioner (101) with progressively reduced leakage, comprising a poppet valve assembly (150) comprising a swivel assembly (110) and a pair of poppet valve assembly (150), a poppet assembly (320) of the poppet valve assembly (150) has a conical tilting freedom (103) around its axis of assembly (151), in a first stable state, the swivel assembly (110) tilts towards a first side (104A) and a rubbing or a lapping action is caused between the first sealing surface (241) and the outer sealing surface (332), and between an inner sealing surface (352) of the poppet body two (350) and the chamber sealing surface (316) of the guide chamber (301), in a second stable state, the swivel assembly (110) tilts towards a second side (104B) and the lapping action is caused between the second sealing surface (261) and the outer sealing surface (332), and between the inner sealing surface (352) of the poppet body two (350) and the chamber sealing surface (316) of the guide chamber (301).

An example valve includes: (i) a valve body defining a longitudinal cavity, where the valve body includes a supply inlet and an operating outlet; (ii) a cage disposed in the longitudinal cavity, where the cage includes (a) a first opening fluidly coupled to the supply outlet, and (b) a second opening fluidly coupled to the operating outlet; and (iii) a spool mounted within the cage and configured to move axially therein. When the valve is actuated, the spool moves within the cage to form a gap, thereby allowing pressurized fluid to flow from the supply inlet through the first opening, the gap, and the second opening to the operating outlet. A flow area defined around an exterior peripheral surface of the spool changes upstream from the gap at a first rate, and changes downstream from the gap at a second rate that is different from the first rate.

A servo valve assembly includes a housing defining a cylindrical cavity having a central axis, and a spool disposed in the cavity and co-axially aligned with the central axis. A pair of transition portions define opposing conical cavity surfaces each connect a respective one of first and second cylindrical cavity portions with a third cylindrical cavity portion. The spool comprises a pair of blocking members projecting radially, and each of the blocking members defines a conical blocking surface opposing a respective one of the conical cavity surfaces to define a fluid flow passage therebetween. A cone angle of each conical blocking surface relative to the central is equal to a cone angle of the opposing conical cavity surface relative to the central axis. The spool is moveable along the central axis to vary a flow area of the flow passages between the conical blocking surfaces and the conical cavity surfaces.

A hydraulic valve includes an on/off seat-type main valve with two ports having a displaceable poppet for opening and closing the main flow channel; an on/off seat-type pilot valve with three ports, with a magnetomotive force producing coil, a magnetic circuit, and an anchor movable with the magnetomotive force produced by the coil; and a frame with required channels and spaces for the poppet and for the anchor. Closing the inlet channel displaces the poppet and opens the main flow channel. Opening the inlet channel forces the poppet to close the main channel. The anchor includes a frame with a first sealing element for closing the low-pressure outlet channel of the pilot valve and with a second sealing element for securing the closing of the high-pressure inlet channel of the pilot valve. The sealing surface of the second sealing element is movable in relation to the frame of the anchor.

The present invention provides a valve including: an inlet unit IL; an outlet unit OL perpendicular to the inlet unit; and an opening/closing unit. The opening/closing unit includes: a rod to open or close the discharge port while extending or retracting in the discharge port in a flow direction of the fluid, having a poppet to open or close the discharge port, and having a piston to be pressed by a pilot gas; a body having a guide to accommodate the rod and guide the extension and retraction of the rod, and pressing spaces into which the pilot gas is introduced; and a solenoid valve to supply the pilot gas into the pressing spaces, in which the opening/closing unit has no spring, and in which a diameter of a seat, which comes into contact with the poppet in the outlet unit, is greater than a diameter of the guide.

Provided is a swing-back preventing apparatus capable of preventing a hydraulic actuator in a stop state from operating by undesired load. The swing-back preventing apparatus includes a housing, a piston, and a pair of biasing members. First and second spaces are formed between the piston and the housing, and the piston includes a pair of communication passages that are communicable with first and second spaces. When the piston is located at a first offset position, the first space is blocked from a first port. When the piston separates from the first offset position, the first space is connected to the first port. When the piston is located at a second offset position, the second space is blocked from a second port. When the piston separates from the second offset position, the second space is connected to the second port. When the piston is located at a position on the first offset position side of a neutral position, a first communication passage is connected to the first space. When the piston is located in a range from the neutral position to the second offset position, the first communication passage is blocked from the first space. When the piston is located at a position on the second offset position side of the neutral position, a second communication passage is connected to the second space. When the piston is located in a range from the neutral position to the first offset position, the second communication passage is blocked from the second space.