A work machine includes directional control valves 43 and 44 each controlling a direction and a flow rate of a pressurized fluid supplied to each a boom cylinder 32 and a bucket cylinder 36; operation amount sensors 51a, 52a, and 52b detecting operation amounts of operation devices 51 and 52; a variable flow control valve 45 that can restrict the flow rate of the pressurized fluid in a meter-in passage of the directional control valve 44 related to the bucket cylinder 36; and a controller 60 controlling the variable flow control valve on the basis of the detection results by the operation amounts from the operation amount sensors, and the controller changes over an action mode to any one of a normal mode for restricting the flow rate of the pressurized fluid by the variable flow control valve and a responsiveness priority mode for not restricting the flow rate of the pressurized fluid by the variable flow control valve in response to the detection results of the operation amounts of the plurality of operation devices. It is thereby possible to enhance responsiveness in an action that requires responsiveness such as an action in which an operation amount of an operation lever frequently changes in a short period of time and to suppress a decline in work efficiency.

There is provided a hydraulic driving device for working machine having operability handling a change in burden weight in a front working device due to a loaded burden and the like when the working machine that accumulates energy in an accumulator and recovers and regenerates the energy performs an operation of lowering the front working device. A hydraulic driving device 5 includes a main pump 101, a boom cylinder 3, a tank 20, a flow rate control valve 6, an accumulator 300, a first differential pressure control valve 201, and a second differential pressure control valve 202. The first differential pressure control valve 201 is located between the boom cylinder 3 and the accumulator 300. The first differential pressure control valve 201 performs control on discharge oil from the boom cylinder 3 such that a differential pressure between before and after the flow rate control valve 6 becomes a target differential pressure. The second differential pressure control valve 202 is located between the accumulator 300 and the tank 20. The second differential pressure control valve 202 performs control on the discharge oil such that a differential pressure between an upstream pressure and a downstream pressure of the flow rate control valve 6 and the first differential pressure control valve 201 becomes the target differential pressure. The first and the second differential pressure control valves 201 and 202 are configured such that the target differential pressure increases according to an increase in pressure of the discharge oil.

A flow control valve apparatus includes: a housing including two pump ports, two tank ports, a first supply/discharge port, a second supply/discharge port, and a spool hole; a first spool configured to switch a connection status among one of the pump ports, one of the tank ports, and the first supply/discharge port depending on a position of the first spool; a first actuator configured to move the first spool to each of a first supply position and a first discharge position; a second spool configured to switch a connection status among the other pump port, the other tank port, and the second supply/discharge port depending on a position of the second spool; and a second actuator configured to move the second spool to each of a second supply position and a second discharge position. The first spool and second spool are inserted in the spool hole so as to reciprocate.

When hydraulic fluid discharged from a hydraulic actuator is to be recovered for driving a different hydraulic actuator, the recovery frequency is increased to achieve further energy saving. To this end, a pressure increasing circuit 36 is provided in which a communication pressure increasing valve 12 is disposed in a communication passage 26 that connects a bottom side line 23 of and a rod side line 24 a boom cylinder 4. A recovery control valve 11 is controlled such that, when a first operation unit 5 is operated in a boom lowering direction (own weight falling direction of the boom) and a second operation unit 6 is operated simultaneously, only if the pressure at the bottom side of the boom cylinder 4 is higher than the pressure at the arm cylinder side that is a recovery destination of hydraulic fluid, the recovery control valve 11 is opened to recover the flow rate discharged from the bottom side of the boom cylinder 4 to the arm cylinder side.

An example robot includes a hydraulic actuator cylinder controlling motion of a member of the robot. The hydraulic actuator cylinder comprises a piston, a first chamber, and a second chamber. A valve system controls hydraulic fluid flow between a hydraulic supply line of pressurized hydraulic fluid, the first and second chambers, and a return line. A controller may provide a first signal to the valve system so as to begin moving the piston based on a trajectory comprising moving in a forward direction, stopping, and moving in a reverse direction. The controller may provide a second signal to the valve system so as to cause the piston to override the trajectory as it moves in the forward direction and stop at a given position, and then provide a third signal to the valve system so as to resume moving the piston in the reverse direction based on the trajectory.

A hydraulic fluid energy regeneration system for a work machine capable of securely maintaining a brake pressure even when a solenoid valve or the like is erroneously rendered open by an electrical failure is provided. The hydraulic fluid energy regeneration system for a work machine, including a first hydraulic actuator; a second hydraulic actuator; and a first hydraulic pump that supplies a hydraulic fluid to the first hydraulic actuator via a first hydraulic line, includes: an upper control valve that is connected to a discharge side on which the hydraulic fluid is discharged from the second hydraulic actuator when an object to be driven by the second hydraulic actuator falls under its own weight, and that can regulate a flow rate of the hydraulic fluid discharged from the second hydraulic actuator; a communication hydraulic line that connects the upper control valve to a hydraulic fluid tank; a lower control valve that is provided in the communication hydraulic line and that can regulate a flow rate of the hydraulic fluid discharged from the upper control valve to the hydraulic fluid tank; and a regeneration hydraulic line that has one end side connected to a branch section between the upper control valve and the lower control valve in the communication hydraulic line and that has an other end side connected to the first hydraulic line.

The present invention relates to a hydraulic valve arrangement for controlling/regulating at least one hydraulic consumer of a mobile machine, with a summation interconnection of at least two hydraulic valves and at least one consumer interconnection of hydraulic valves, wherein the outputs of the summation interconnection are hydraulically connected with the inputs of the consumer interconnection, wherein at least one backflow valve is provided in the consumer interconnection. According to the invention, the at least one backflow valve for throttling a consumer return volume flow opens or closes in dependence on a consumer inflow pressure and comprises at least one main piston arranged in a bushing and at least two further pistons arranged in a lid separate from the bushing, wherein the main piston and the control piston interact with each other via a compression spring.

A lifting control device includes: a position acquisition portion configured to acquire an extended or contracted position of the hydraulic cylinder; a target setting portion configured to set a target position of the hydraulic cylinder; a control portion configured to control an energized amount of the solenoid valve; and an input judging portion configured to judge whether the operational input is an opening command to perform an opening control in which the solenoid valve is made to be fully open or is a positional control command to perform a positional control in which the solenoid valve is actuated according to an operation input amount to control the extended or contracted position of the hydraulic cylinder, wherein when the operational input is judged as the opening command by the input judging portion, the opening control is performed due to the non-integral type control by the control portion.

Universal control circuitry for an electro-hydraulic valve actuator system includes logic gate circuitry to control one or more of a closing solenoid valve, an opening solenoid valve, an emergency shutdown solenoid valve, and a hydraulic fluid pump motor to route hydraulic fluid through a hydraulic circuit to actuate a valve via a hydraulic actuator according to received commands. The universal control circuitry is configured to control operation for multiple different configurations of a hydraulic valve actuator system including double-acting configurations, single-acting spring-to-open configurations, and single-acting spring-to-close configurations, each with or without an emergency shutdown arrangement (which may be configured to trip based on an external shutdown input alone or in combination with a local system power failure), a hydraulic accumulator, and maintained or momentary input commands.

A valve member having a supply pressure and a method of controlling the supply pressure in the valve member includes a valve body having a fluid inlet, a fluid outlet, and a controlled port. The valve member includes a spool moveable within the valve body to fluidly connect at least one of the fluid inlet and the fluid outlet with the controlled port. The spool includes an end in fluid communication with a control pressure port and a pin received within the end of the spool that is moveable relative to the spool. Fluid flow through the control pressure port acts against a cross-sectional area of the pin and an annular area of the spool to modulate the supply pressure through the valve member.