A control valve assembly for indirect pneumatic control and method for controlling a working fluid pressure, which enable precise, sensitive and speed-variable controlling. The assembly includes two valve units, a working fluid inlet, and a control fluid inlet. A working fluid channel connects the working fluid inlet through the two valve units to an outlet. A valve piston arranged within a valve cylinder of the valve units is movable between open and closed positions. A spring element biases the valve piston toward the closed position, and a control pressure chamber applies a control pressure counteracting the spring element's bias. When a control pressure is applied in the first chamber, the first valve piston is moved to the open position. Two opposite valve surfaces form a valve opening opened at varying widths when the valve piston is moved in the valve cylinder because of a changing control pressure, and the working pressure can be finely adjusted corresponding to the valve opening width depending on the control pressure.

The present disclosure provides: at least one component of a rotary valve subassembly; a rotary valve assembly including the rotary valve subassembly; a hydraulic circuit including the rotary valve assembly; an assembly including a robot that incorporates the hydraulic circuit; and a method of operating the rotary valve assembly. The at least one component of the rotary valve subassembly includes a spool. The at least one component of the rotary valve subassembly includes a sleeve.

An example spool includes a shaft varying in diameter along a length of the shaft, and a plurality of annular lands formed on the shaft and spaced-apart by respective reduced diameter annular neck portions. The plurality of annular lands comprise at least one annular metering land, and wherein the at least one annular metering land comprises: one or more sine notches formed as a portion of a sine wave, and one or more additional notches having a different shape from the one or more sine notches.

An end of a first land has a step difference recessing inward of a radial direction of the first land from the edge portion. The step difference has an end point opposite to the edge portion. A throttle portion protrudes from the start point in an axial direction, and includes an outer-peripheral corner (protrusion round portion) having a curved surface protruding in the axial direction and in the radial direction. When an inlet opening starts to be slightly opened, since a hydraulic fluid is throttled when flowing through a second gate opened between a corner of a sleeve and the protrusion round portion, a rapid increasing of a flow quantity of the hydraulic fluid and an instability of a control of the hydraulic fluid can be suppressed.

A first flow path area at a position where one of multiple openings of a sleeve and one of multiple grooves of a spool overlap with each other is different in size from a second flow path area at a position where another one of the openings of the sleeve and another one of the grooves of the spool overlap with each other. The one opening and the one groove form a flow path for connecting one of one pressure chamber and the other pressure chamber to a fluid supply source, due to displacement of the spool. The other opening and the other groove form a flow path for connecting another one of the other pressure chamber and the one pressure chamber to a fluid discharge port, due to the displacement of the spool.

The invention relates to a flow control valve adapted for use as a flow-dividing and flow-combining valve in hydraulic devices, comprising: a valve body having a first longitudinally extending bore, an outer spool slidably positioned within the bore, the outer spool having an axially extending passageway, a pair of axially extending inner spools slidably positioned within the passageway, the valve body having a first port and a pair of second ports, the outer spool having at least a first opening communicating with the first port and with the passageway, and at least two pairs of second openings therethrough. At least one second opening of each pair is of non-constant longitudinal section narrowing from the outer face of the outer spool on at least a part of the thickness of the second opening, so that a lateral side of the second opening offers an obstacle where a part of the fluid flow entering the second opening crashes before entering the inner spool.

A hydraulic control valve unit includes an input port hydraulically coupled to a pump, a working port hydraulically coupled to the working load, and a return port connected to a hydraulic tank. The unit includes a control slide movable into different working positions in an axial direction for controlling a hydraulic flow between the hydraulic ports and a slide housing surrounding the control slide. The control slide includes a control segment which is delimited in the axial direction by a control edge, and cooperates with an axial housing segment of the slide housing for controlling a flow cross section for hydraulic flow at the control segment. The control slide is rotationally driven about an axis of rotation in a rotational direction. The control edge of the control segment or the housing segment cooperating with the control segment is designed such that the flow cross section has a different size depending on a rotational position of the control slide.

There is provided a spool type flow control valve including a sleeve in which a supply port, a control port, and an exhaust port are formed, and a spool accommodated to be movable in an axial direction inside the sleeve and including a valve body. The valve body controls an opening area of the control port so that a flow rate is controlled. A difference between a maximum value and a minimum value of an internal leakage amount which is a flow rate at which a gas supplied from the supply port is discharged from the exhaust port in a state where the control port is shut off is equal to or smaller than a predetermined threshold.

An example spool includes a shaft varying in diameter along a length of the shaft, and a plurality of annular lands formed on the shaft and spaced-apart by respective reduced diameter annular neck portions. The plurality of annular lands comprise at least one annular metering land, and wherein the at least one annular metering land comprises: one or more sine notches formed as a portion of a sine wave, and one or more additional notches having a different shape from the one or more sine notches.

A control slide for use in a slide valve is disclosed. The control slide has a central axis and at least one first portion which is circular-cylindrical with respect to the central axis, all the first portions having the same diameter. The control slide further has at least one assigned second portion which is adjacent to each first portion, which second portion ends toward the first portion with an end face which extends inclined by at least 45° in relation to the central axis so that the first portion, together with the end face, forms a circular ring edge which extends around the central axis in a circular ring shape having a substantially constant cross-sectional shape. The control slide is made of steel. The at least one first portion is surface-hardened such that the hardness on the surface of the control slide decreases from the first portion via the circular ring edge toward the end face. The mentioned cross-sectional shape of the circular ring edge is composed of a straight portion and a curved portion without abrupt bends. The straight portion directly adjoins the assigned first portion, the curved portion directly adjoins the straight portion and the end face, the diameter of the control slide in the straight portion decreases from the first to the second portion. The hardness on the surface of the control slide decreases steadily from the end of the straight portion, which faces the first portion, into the first portion.