A hydraulic apparatus comprises first and second manifolds each of which is connected to a plurality of actuators via corresponding actuator valves connected in parallel and operated responsive to inputs to regulate the flow of fluid to the actuators. A plurality of working chambers are connectable to either the first or second manifold and have a net flow which is controlled responsive to a negative feedback signal. The negative feedback signal is determined in response to a calculated pressure or flow rate in virtual fluid flow paths extending from the first and second manifolds.

A hydraulic excavator drive system includes: a first pump that is connected to a head-side chamber of a boom cylinder by a head-side line and to a rod-side chamber of the boom cylinder by a rod-side line to form a closed circuit; and a second pump that supplies hydraulic oil to at least one of an arm cylinder or a bucket cylinder. The hydraulic excavator drive system further includes a switching valve located on a relay line that connects a supply line extending from the second pump to the rod-side line. The switching valve opens the relay line at a boom raising operation and blocks the relay line except at the boom raising operation.

A working machine includes a controller that performs shift shock reduction control when shift-down switching from a second state to a first state, in which a motor speed can be increased up to a first maximum speed lower than a second maximum speed available in the second state, is performed. The controller includes a first processor configured to, based on a drop amount that is a difference between target and actual numbers of revolutions of a prime mover, compute a first reduction amount for reducing an amount of hydraulic fluid supply from a traveling pump to a traveling motor, a second processor configured to compute a second reduction amount based on a degree of straight traveling of a machine body, and a reduction controller configured to, based on the first or second reduction amount, whichever is larger in absolute value, perform the shift shock reduction control.

A machine control system can store model weights determined via machine learning using a training dataset correlating preset hydraulic valve displacements to measured movement parameters of a machine component. The machine control system can receive an input command for the component and machine state data from machine sensors. A control mapping model can use the model weights to map a combination of the input command and the machine state data into a predicted displacement of the hydraulic valve that causes movement of the component in response to the input command.

A multi-control valve device includes: a valve block including a plurality of valve holes; a plurality of spools movably housed in the plurality of valve holes in a one-to-one correspondence; one or more attachment parts provided on the valve block; and a plurality of solenoid valves provided on the one or more attachment parts in a one-to-one correspondence with the plurality of spools and each of which reduces a primary pressure, outputs a secondary pressure to a corresponding one of the plurality of spools, and moves the spool. The valve block includes a primary pressure supply passage through which the primary pressure is supplied to each of the plurality of solenoid valves.

A hoist valve assembly for a work machine cylinder includes a main control valve, a counterbalance valve and a counterbalance shutoff valve. A main control valve raise position connects a head end of the cylinder with a pressurized fluid source and a rod end of the cylinder to a low pressure reservoir to extend the cylinder. The counterbalance valve is between the rod end and the main control valve, is biased to a closed position and has an open position connecting the rod end to the low pressure reservoir. Rod end and head end pressure signals apply force to the counterbalance valve toward the open position. The counterbalance shutoff valve is positioned between the head end and the counterbalance valve, and has a normal position to apply the head end pressure signal to the counterbalance valve and a shutoff position that blocks the head end pressure signal from the counterbalance valve.

A hydraulic system of a construction machine includes: control valves interposed between a variable displacement main pump and hydraulic actuators; and first solenoid proportional valves connected to pilot ports of the control valves. The hydraulic system further includes: a regulator that changes a displacement of the main pump; and a second solenoid proportional valve connected to an auxiliary pump by a primary pressure line, the second solenoid proportional valve outputting a secondary pressure to the regulator through a secondary pressure line. A switching valve is interposed between the auxiliary pump and the first solenoid proportional valves, and includes a pilot port that is connected to the secondary pressure line by a pilot line.

A compact utility loader compact utility loader comprising a frame, and a loader arm configured to support an attachment. The compact utility loader additionally comprises a first link pivotably secured to the frame, a second link pivotably secured to the frame, and an actuator configured to raise and lower the loader arm. The actuator is not simultaneously secured to both the frame and the loader arm.

An excavator includes a traveling body, an upper turning body rotatably provided on the traveling body, an attachment which has a boom, an arm, and a bucket and is attached to the upper turning body, and a controller configured to perform a control of a cylinder of at least one shaft of the attachment so as to suppress a vibration of the traveling body or the upper turning body, which is caused by an aerial operation of the attachment.

To improve operability and work efficiency while achieving reduction of the number of parts and simplification of circuit structure, in a hydraulic control system equipped with hydraulic actuators whose hydraulic power sources are both the first, second hydraulic pumps. The hydraulic control system is provided with the stick directional switching valve; the main-side, sub-side supply oil passages connecting the hydraulic pumps to the stick directional switching valve; and the stick flow rate control valve which is placed in the sub-side supply oil passage, and controls the supply flow rate from the hydraulic pump when the supply flow rate to the stick cylinder requires the supply flow rates from both the hydraulic pumps, wherein the stick directional switching valve is configured such that the discharge flow rate control is performed in the entire area of the spool stroke, and the supply flow rate control is performed at the first region of the former half of the spool stroke, but not performed at the second region of the latter half of the spool stroke.