A hydraulic system for an automatic transmission of a motor vehicle, including a high pressure circuit in which a pressure accumulator, at least one clutch and a gear selector are connected, and comprising a low pressure circuit for cooling the clutch, wherein the high pressure circuit and the low pressure circuit have at least one hydraulic pump that can be driven by an electric motor, and including a control unit that actuates the electric motor of the hydraulic pump when a pressure accumulator charging requirement is detected, wherein the high and low pressure circuits are connected via a bypass line to an integrated accumulator charging valve.

A servovalve includes a supply port and a control port; a moveable valve spool arranged to regulate flow of fluid from the supply port to the control port in response to a control signal and a drive assembly configured to axially move the valve spool relative to the fluid transfer assembly in response to the control signal to regulate the fluid flow; wherein the drive assembly comprises a first fluid channel providing a flow path for fluid from the supply port to a first end of the spool and provided with a first flow control orifice. The assembly also includes a second fluid channel providing a rotating element provided with a cam profile located between the first flow control orifice and the second flow control orifice. The assembly also includes drive means arranged to rotate the rotating element.

A valve, which is characterized in that between a neutral position (38) of a control spool (STS) and one of its end positions (34, 42) a regeneration position (36) is provided. In the regeneration position, two utility ports (A, B) are interconnected in a fluid-conveying manner, or a floating position (40) is provided, in which these utility ports (A, B) are interconnected in a fluid-conveying manner. A further valve is characterized in that by a further motion of the control spool (STS) in the same direction, as that, in which a fluid connection is established between the utility ports (A, B) starting from the neutral position (38), this fluid connection is interrupted.

An electro-hydraulic proportional valve includes: a valve core; a valve sleeve, sleeving an outside of the valve core; a valve body, sleeving an outside of the valve sleeve and fixedly connected to the valve sleeve; a left end cap, covering an end of the valve body, a left sensitive cavity being defined by the left end cap, the valve body, and the valve sleeve; a right end cap, covering the other end of the valve body, a right sensitive cavity being defined by the right end cap, the valve body, and the valve sleeve; a driving mechanism disposed out of the valve body; and a transmission mechanism connected to the driving mechanism and the valve core.

The present invention provides an engineering machinery hydraulic system with compensation differential pressure controllable, uses an electronic pressure compensating valve to solve the problem of flow mismatch under conditions of pressure over-limit and flow saturation, and realizes proportional shunt control and high-precision flow distribution of the system. The engineering machinery hydraulic system disclosed in the present invention has the advantages of low energy consumption, fast response speed, and high flow control precision.

A servo valve includes a fluid transfer valve assembly comprising a supply port and a control port; a valve spool arranged to regulate flow of fluid from the supply port to the control port in response to a control signal; and a drive means configured to move the valve spool relative to the fluid transfer assembly in response to the control signal to regulate the fluid flow. The drive means is arranged to rotate the spool relative to the fluid transfer assembly, the spool provided with openings arranged to selectively align with or block flow channels in the fluid transfer assembly according to the direction and degree of rotation of the spool.

A manipulator includes an articulated boom configured to be folded out. The articulated boom includes a turntable that can be rotated about a vertical axis, a plurality of boom segments, electrically-actuated proportional valves, and a remote control. The boom segments are pivotable via respective drive assemblies. The electrically-actuated proportional valves are respectively arranged directly on or in proximity to the respective drive assemblies to be controlled. The remote control includes at least one control lever configured to be displaced in a plurality of actuating directions. The manipulator further includes an electronic controller configured to actuate the drive assemblies via a travel command. The travel command indicates a desired movement of the boom tip. The travel command is generated in response to displacement of the control lever into at least one of the plurality of actuating directions. And, the travel command causes actuation of the respective electrically-actuated proportional valves.

1. Control Device

2. A control device for controlling a hydraulic consumer (2), such as a working cylinder, consisting of at least one control valve (18) having a control spool (20), which is guided in a valve housing (22) in a longitudinally movable manner and which can be actuated by means of an electric motor (24) and which can be controlled by means of control electronics (MC), which receive input signals from a sensor device (58, 60, 62), which detects at least one operating state of the consumer (2).

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.

The invention relates to a valve, which is characterized in that between a neutral position (38) of a control spool (STS) and one of its end positions (34, 42) a regeneration position (36) is provided, in which two utility ports (A, B) are interconnected in a fluid-conveying manner, or a floating position (40) is provided, in which these utility ports (A, B) are interconnected in a fluid-conveying manner. The invention relates to a further valve, which is characterized in that by a further motion of the control spool (STS) in the same direction, as that, in which a fluid connection is established between the utility ports (A, B) starting from the neutral position (38), this fluid connection is interrupted.