Abstract: An example hydraulic system includes a hydraulic cylinder actuator comprising a cylinder and a piston, wherein the piston comprises a piston head and a rod extending from the piston head, wherein the piston head divides an internal space of the cylinder into a first chamber and a second chamber, and wherein the hydraulic cylinder actuator is unbalanced; a first pump driven by a first electric motor to provide fluid flow to the first chamber or the second chamber of the hydraulic cylinder actuator to drive the piston; a boost flow line; a hydraulic motor actuator; and a second pump driven by a second electric motor, wherein the second pump is fluidly coupled to the boost flow line to provide boost fluid flow to the hydraulic cylinder actuator.

Abstract: A fluid distribution manifold may receive a first required flow rate for a first flow of fluid that flows to a fluid handling device or a reservoir. A first operation state may be determined for a first valve assembly that regulates the first flow, the manifold may operate the first valve assembly based on the first operation state, and a first position tracker may be incremented based on the first operation. Based on a value of a cycle tracker, the manifold may identify a second valve assembly in an operation cycle and access a second control input that includes a second required flow rate for a second flow of fluid regulated by the second valve assembly. The manifold may cause the second valve assembly to operate based on at least one of a second operation state and a change in the second actual flow rate resulting from the first operation.

Abstract: To provide a construction machine that has a hydraulic system mounted thereon in which a closed-circuit pump, and an open-circuit pump and a proportional valve are arranged as a pair, and that makes it possible to use an unused open-circuit pump or proportional valve to accelerate the speed of a single rod hydraulic cylinder when the single rod hydraulic cylinder and a hydraulic motor are driven simultaneously. A controller (51) controls a cap-side selector valve (46) and a rod-side selector valve (47) such that a particular open-circuit pump (15) not connected to a single rod hydraulic cylinder (3) is connected to the single rod hydraulic cylinder, and controls an opening area of a particular proportional valve (49) provided on a flow line that connects a delivery port of the particular open-circuit pump to a tank, when the single rod hydraulic cylinder and a hydraulic motor (7) are driven simultaneously.

Abstract: A work vehicle includes a valve for switching between a merging position for causing a first oil passage for driving a bucket and a second oil passage for driving an arm to communicate with each other, and a diverging position for separating the first oil passage and the second oil passage. The work vehicle is adapted to switch the valve from the merging position to the diverging position, when one of a pump pressure in the first pump and a pump pressure in the second pump comes to be equal to a predetermined value during an excavation operation. The work vehicle is adapted to control both pumps, such that the amount of the oil discharged from the first pump is larger than the amount of the oil discharged from the second pump, when the pump pressure in the first pump is equal to or more than the predetermined value.

Abstract: A hydraulic system for a work machine includes a tank to store an operation fluid, a hydraulic device to be operated by the operation fluid, a control valve to control the hydraulic device, a first fluid tube connecting the hydraulic device and the control valve, the first fluid tube being to supply the operation fluid from the control valve to the hydraulic device, a second fluid tube branching from the first fluid tube and connected to the tank, a switch valve provided to the second fluid tube, the switch valve being to control a flow rate of the operation fluid, and an oil cooler provided to the second fluid tube between the switch valve and the tank.

Abstract: A camera crane mobile base for carrying a camera crane includes a first powered remotely controllable steering system having first and second axle assemblies at a first end of a chassis. A second steering system including third and fourth axle assemblies is provided at a second end of the chassis. A first electrically powered remotely controllable propulsion system includes an electric propulsion motor connected to first and second axles in the first and second axle assemblies. A telescoping center post is pivotally attached to the chassis. An on-board hydraulic system may power the first steering system and the telescoping center post.

Abstract: A system includes a processor and a memory coupled to the processor. The memory stores instructions that cause the processor to determine a first motion envelope of an object. The first motion envelope corresponds to a kinematic envelope of positions of the object which are achievable. The instructions also cause the processor to determine an operational envelope of the object based on an intersection of the first motion envelope and a second motion envelope of the object. The second motion envelope corresponds to a range of motion of the object constrained by dynamic motion limits of the object, and the operational envelope is indicative of a range of motion of the object during operation of the object. The instructions further cause the processor to generate a virtual model of the object based on the operational envelope. The virtual model is used to virtually model operation of the object.

Abstract: A working machine includes a prime mover, a hydraulic pump to be driven by power of the prime mover and to output operation fluid, a hydraulic actuator to be operated by the operation fluid, and a control device. The control device has a revolving-speed controller to increase and decrease a revolving speed of the prime mover, a first setting portion to set a limit value of the revolving speed of the prime mover, and a revolving-speed limiter to limit the revolving speed of the prime mover set by the revolving-speed controller to the limit value set by the first setting portion.

Abstract: A hydraulic system includes a hydraulic pump, an output fluid tube connected to the hydraulic pump, an operation fluid tube connected to a hydraulic device, an unload valve connected to the output fluid tube, and having: a supply position in which the operation fluid in the output fluid tube is supplied to the operation fluid tube; and a restrain position in which supply of the operation fluid to the operation fluid tube is restrained, an operation valve connected to the output fluid tube, a control fluid tube connecting the operation valve and the hydraulic device, a warmup fluid tube connecting the control fluid tube and the operation fluid tube, and a check valve provided in the warm-up fluid tube and being for allowing the operation fluid to flow from the control fluid tube side toward the operation fluid tube, and for blocking the operation fluid from flowing side from the operation fluid tube toward the control fluid tube.

Abstract: A hydraulic system is capable of improving the acceleration performance of a slewing motor and suppressing an increase in the flow rate of hydraulic fluid supplied to the slewing motor. The hydraulic system includes a slewing speed sensor that detects a slewing speed of a slewing body and a controller that controls a slewing motor capacity, which is a capacity of the slewing motor. The controller controls the slewing motor capacity so as to make the slewing motor capacity when the slewing speed is in a low speed range be greater than the slewing motor capacity when the slewing speed is in a high speed range.

Abstract: A hydraulic apparatus for stretching conductors for power lines comprising: a variable displacement hydraulic pump (10) that supplies by means of a hydraulic fluid a hydraulic motor (11) with a closed circuit connection; a displacement regulation system (15) of said hydraulic pump (10); a regulation system (20) of said hydraulic apparatus; characterised in that said regulation system (20) comprises: an inlet (21) that receives said hydraulic fluid that supplies said hydraulic motor (11); a first outlet (22) that supplies said displacement regulation system (15); a second discharge outlet (23); a flow limiter (30) connected to said inlet (21); a regulatable valve (31) connected to said flow limiter (30); a tap (36) connected between the outlet of said regulatable valve (31) and said first outlet (22); a measurement instrument (33) connected to the outlet of said regulatable valve (31), to measure the regulation pressure of said regulation system (20); a safety valve (34) connected to the outlet of said regulat

Abstract: A method for estimating the remaining useful life of a pressure compensator of a subsea arrangement, the method including determining displacement data related to displacements of the pressure compensator during a time period; and estimating the remaining useful life of the pressure compensator in relation to a failure mode of the pressure compensator based on the determined displacement data of the pressure compensator. A system including a subsea arrangement and a control system, a computer program product, and a computer program, are also provided.

Abstract: A construction machine incorporates a hydraulic closed circuit system capable of suppressing, even where a selector valve is stuck in an open state by a failure of the selector valve or a control system therefor, unintended operation of a hydraulic actuator and continuing operation of a machine body. The construction machine includes first sensors that detect open-closed states of a plurality of switching valves, first compulsory valve closing devices that change over the plurality of switching valves to a closed position irrespective of open-close control by a machine body controller, and a valve device controller that controls, when it is detected based on the open-closed states of the plurality of selector values detected by the first sensors that one of the plurality of selector values is stuck in an open state, the first compulsory valve closing device such that other selector valve connected to one of the plurality of closed circuit pumps to which the one selector valve is connected is closed.

Abstract: A working machine includes a hydraulic pump, a first traveling device to be driven by a first traveling hydraulic actuator, a second traveling device to be driven by a second traveling hydraulic actuator, a first output tube to connect a first output port of the hydraulic pump to the first traveling hydraulic actuator, a second output tube to connect a second output port of the hydraulic pump to the second traveling hydraulic actuator, a first operation device to operate the first traveling device, a second operation device to operate the second traveling device and a correction mechanism to equalize a driving force of the first traveling hydraulic actuator and another driving force of the second traveling hydraulic actuator when the first operation device and the second operation device are operated each at same operation extents to perform a straight-traveling operation.

Abstract: Provided is a hydraulic driving apparatus capable of operating hydraulic actuators that actuate a boom, an arm, and a tip attachment at respective suitable speeds. The hydraulic driving apparatus includes a first hydraulic pump connected to a first main actuator, a second hydraulic pump connected to a second main actuator and an attachment actuator, a first merging selector valve that allows hydraulic fluid to be supplied from the first hydraulic pump to the second main actuator, and a power distribution control device that operates displacement of the first and second hydraulic pumps so as to decrease power distribution from a pump drive source to the second hydraulic pump and increase power distribution from the pump drive source to the first hydraulic pump when a specified combined operational action is performed on the second main actuator and the attachment actuator.

Abstract: A fluid pressure control device includes a first switching valve provided on a downstream of a first travel control valve in the first main passage and having an open position and a priority position, a second switching valve provided on a downstream of a second travel control valve in the second main passage and having an open position and a priority position, and a merging passage connecting a downstream of the first switching valve and a downstream of the second switching valve. In a state where first work control valves and second work control valves are not operated and the first travel control valve is operated, the first switching valve is at a priority position, and in a state where the first work control valves and the second work control valves are not operated and the second travel control valves is operated, the second switching valve is at a priority position.

Abstract: A travel control system for construction machinery includes first and second hydraulic pumps, a first travel motor and a second travel motor operable by a working oil discharged from the first hydraulic pump or the second hydraulic pump, at least one actuator operable by the working oil discharged from the first hydraulic pump or the second hydraulic pump, a straight travel valve to be switched between a first position and a second position, first and second travel motor control valves configured to control amounts of the working oil supplied to the first and second travel motors, first and second spool displacement adjusting valves supplying pilot signal pressures to the spools of the first and second travel motor control valves respectively, and a controller configured to output a control signal to each of the first and second spool displacement adjusting valves corresponding to a manipulation signal of an operator.

Abstract: The work vehicle includes: a working device; an auxiliary machine; and a priority valve that is switched between a normal position for directing pressure oil from an accessory pump toward the auxiliary machine and a merging position for directing the pressure oil from the accessory pump toward the working device. The work vehicle includes a control device that holds the priority valve in the normal position in case either the forward direction or the reverse direction which is indicated by a forward reverse operating device and a travel direction of the work vehicle do not match each other, and that switches the priority valve to the merging position in case either the forward direction or the reverse direction which is indicated by the forward reverse operating device and a travel direction of the work vehicle match each other and an operating device is in an operated state.

Abstract: A hydraulic control system for a construction machine includes a hydraulic pump group including a first hydraulic pump, a second hydraulic pump and a third hydraulic pump; a main control valve including a first spool group that controls a flow of pressurised fluid from the first hydraulic pump and the second hydraulic pump and that includes an operation apparatus spool, a driving spool and a merging spool, a second spool group that controls a flow of pressurised fluid from the third hydraulic pump and that includes a rotating spool, and a straight driving valve between the first spool group and the second spool group; a first pilot signal line connected to the operation apparatus spool that provides a supply path for a pilot pressurised fluid that is applied to switch the operation apparatus spool; a second pilot signal line connected to the driving spool that provides a supply path for a pilot pressurised fluid that is applied to switch the driving spool; and a direction changing valve on the second pilot si

Abstract: A hydraulic valve assembly for a work vehicle includes a fan and brake function module. A first pump supplies hydraulic pressure to a fan circuit and to first and second service brake circuits of the vehicle. A second pump supplies hydraulic pressure to a steering and work function module that in turn supplies hydraulic pressure to a steering circuit and a work function circuit of the vehicle. The hydraulic valve assembly may also include a work control module and an auxiliary module. The modules of the hydraulic valve assembly are separably connected together via interface surfaces.

Abstract: The present disclosure relates to a safety system for a construction machine, and the safety system for a construction machine according to the exemplary embodiment of the present disclosure includes: a pilot pump which supplies a pilot working fluid; multiple spools which are operated by the pilot working fluid to control a supply of a main working fluid and each have a signal unit formed in one region thereof; a signal line which sequentially connects the pilot pump and the signal units of the multiple spools and discharges the pilot working fluid, which is supplied by the pilot pump, to a hydraulic tank; and a pressure sensor which measures pressure in the signal line.

Abstract: A vehicle hydraulic system includes: (a) a hydraulic pump device to be driven by a vehicle drive source to eject a working fluid through first and second outlet ports; (b) a first line passage that guides the working fluid ejected through the first outlet port, with a hydraulic pressure being regulated to a relatively high value; (c) a downstream-side passage in which the hydraulic pressure is regulated to a relatively low value; (d) a path-switching valve device configured to allow the working fluid ejected through the second outlet port, to flow into the first line passage, when the hydraulic pressure is lower than a predetermined value, and configured to allow the working fluid ejected through the second outlet port, to flow into the downstream-side passage, when the hydraulic pressure is higher than the predetermined value; and (e) a bypass passage provided between the second outlet port and the downstream-side passage.

Abstract: The present invention relates to a hydraulic system comprising a first actuator, a first variable displacement pump fluidly connected to the first actuator via a first circuit and adapted to drive the first actuator. The system further comprises a second actuator and a second pump fluidly connectable to the second actuator via a second circuit and adapted to drive the second actuator, wherein the second pump is fluidly connectable to the first actuator via a first control valve, and wherein the second pump is fluidly connectable to the second actuator via a second control valve.

Abstract: The construction machine includes: a work implement driven by a first hydraulic actuator and a second hydraulic actuator; a first directional control valve controlling a flow rate and a direction of a hydraulic fluid supplied to the first hydraulic actuator; a first speed-up directional control valve provided in a second pump line and controlling a flow rate and a direction of a hydraulic fluid supplied to the first hydraulic actuator; a second directional control valve controlling a flow rate and a direction of a hydraulic fluid supplied to the second hydraulic actuator; an excavation load sensor that detects an excavation load imposed on the work implement; and a first speed-up control section that drives the first speed-up directional control valve, and the first speed-up control section is configured to control a driving amount of the first speed-up directional control valve in response to the excavation load.

Abstract: A power steering electrohydraulic system is provided for an electric vehicle, including: at least one reservoir of hydraulic fluid; and at least one hydraulic actuator for actuating a steering rack shaft of the vehicle; at least two electric motor pump units in parallel for supplying the actuator with hydraulic fluid from the reservoir and adjusting the flow rate of the hydraulic fluid supplied to the actuator, and each electric motor pump unit is a motor pump unit operating at a voltage of 24V. A vehicle equipped with such a system is also provided.

Abstract: A hydraulic excavator drive system includes: first and second pumps; arm cylinder; arm first control valve connected to the cylinder by an arm crowding supply line and arm pushing supply line; arm second control valve connected to the supply lines by a first and second replenishment line; and arm operation device that outputs an operation signal corresponding to an inclination angle of an operating lever. The arm second control valve is configured so, when performing an arm crowding operation, an opening area at a meter-in side changes in accordance with the operation signal, and an opening area at a meter-out side is: kept to zero when a predetermined condition is not satisfied; and kept to zero until the operation signal becomes a setting value or greater, and when the operation signal has become the setting value or greater, increases to a maximum value when the predetermined condition is satisfied.

Abstract: A hydraulic fluid energy regeneration apparatus of a work machine includes: a regeneration hydraulic motor driven by a return hydraulic fluid; a first hydraulic pump mechanically connected to the regeneration hydraulic motor; a second hydraulic pump that delivers a hydraulic fluid for driving a hydraulic actuator; a confluence line that causes the hydraulic fluid delivered from the first hydraulic pump to join the hydraulic fluid delivered from the second hydraulic pump; a first adjuster configured to adjust the flow rate of the hydraulic fluid of the first hydraulic pump; and a second adjuster configured to adjust the delivery flow rate of the second hydraulic pump.

Abstract: A hydraulic working machine is provided that uses a variable displacement pump and open center type flow rate control valve for a controlling a hydraulic actuator, and has a negative control throttle disposed in a center bypass oil passage to generate a negative control pressure. A hydraulic pump control system performs virtual bleed-off control for reducing the bleed-off flow rate of the center bypass oil passage, and can operate the hydraulic actuator with the same performance as an open center control. The control system includes a bypass cut valve disposed upstream from the negative control throttle to reduce flow through the center bypass oil passages, and a negative control pressure output valve that outputs a virtual negative control pressure. The control system is configured to reduce the bleed-off flow rate by operating the bypass cut valve when virtual bleed-off control is performed, and to reduce the pump flow rate by the bleed-off reduction flow rate.

Abstract: The present invention relates to a hydraulic system comprising a first actuator and a first pump fluidly connected or connectable to the first actuator via a first circuit and adapted to drive the first actuator. The system further comprises a second pump, a second actuator and a third pump, the third pump being fluidly connected or connectable to the second actuator via a second circuit and adapted to drive the second actuator. To assist the first and third pumps in moving the first and second actuators, the second pump is connectable to the first and second actuators via first and second control valves.

Abstract: A direction control valve group for a construction machine that controls an amount of pressure oil supplied to a hydraulic actuator from a hydraulic pump that discharges the pressure oil is provided. The direction control valve includes a cylinder port that supplies the pressure oil to the hydraulic actuator, a bridge passage that is switchably connected and disconnected to the cylinder port according to a change in position of a first spool, and an internal passage that supplies the pressure oil discharged from the hydraulic pump to the bridge passage. The first spool is provided in the internal passage.

Abstract: A flow rate control apparatus for construction equipment includes: a boom cylinder driven by hydraulic fluid; a first control valve for controlling a hydraulic fluid flow supplied to the boom cylinder; an option actuator driven by hydraulic fluid; a second control valve for controlling a hydraulic fluid flow supplied to the option actuator; a boom cylinder manipulation lever and an option actuator manipulation lever; a confluence line selectively confluence the hydraulic fluid supplied to the boom cylinder with the hydraulic fluid of the option actuator; a center bypass switching valve provided at the furthest downstream side of a fluid supply path of the first hydraulic pump; a confluence switching valve selectively opening and closing the confluence line; a confluence selection valve applying a pilot pressure to the confluence switching valve; and a controller for controlling the confluence selection valve.

Abstract: A control system includes: a first hydraulic pump and a second hydraulic pump; a passage connecting the first hydraulic pump and the second hydraulic pump with each other; an opening/closing device provided in the passage and configured to open and close the passage; a control device configured to control the opening/closing device to switch between a split-flow state in which the passage is closed and a connected state in which the passage is open; a first actuator to which hydraulic fluid discharged from the first hydraulic pump is supplied in the split-flow state; and a second actuator to which hydraulic fluid discharged from the second hydraulic pump is supplied in the split-flow state. In the connected state, the control device controls the opening/closing device so that the connected state is maintained even when either one of the first actuator and the second actuator is brought into a driven state.

Abstract: A control system includes: calculating a distribution flow rate of hydraulic fluid to be supplied to first and second hydraulic actuators based on a pressure of hydraulic fluid in the first and second hydraulic actuators and an operation amount operated to drive the first and second hydraulic actuators; calculating merged-state pump output indicating outputs of first and second hydraulic pumps required in a merged state based on the distribution flow rate; calculating separated-state pump output indicating outputs of the first and second hydraulic pumps required in the separated state based on the distribution flow rate; calculating excessive output of an engine based on the merged-state pump output and the separated-state pump output; calculating reduced output of the engine more reduced than target output by correcting the target output of the engine based on the excessive output; and controlling the engine based on the reduced output in the separated state.

Abstract: Provided is a hydraulic drive system including: first and second pumps; a first main supply fluid line and an optional supply fluid line leading to the first pump; a second main supply fluid line leading to the second pump; a main manipulating device for the main actuator; an optional manipulating device for the optional actuator; a bleed-off flow rate regulating section to change the bleed-off flow rate for the second pump; and a bleed-off control section to operate the bleed-off flow rate regulating section to change the discharge flow rate of the second pump in accordance with a control operation applied to the main manipulating device and to make a bleed-off flow rate in a specific combined manipulation state with simultaneous performance of a specific main control operation and an optional control operation be smaller than that in a single main manipulation state.

Abstract: A hydraulic system for a machine includes a plurality of hydraulic component, wherein the hydraulic components include hydraulic actuators and hydraulic motors. The hydraulic system also includes a plurality of hydraulic circuits, and a plurality of hydraulic pumps for supplying hydraulic fluid to the plurality of hydraulic components via the hydraulic circuits. At least one hydraulic component receives hydraulic flow exclusively from a designated one of the hydraulic pumps and at least another, different hydraulic component receives shared hydraulic flow from a flow sharing set of the hydraulic pumps.

Abstract: A control system includes a cylinder pressure data acquisition unit that acquires cylinder pressure data indicating a pressure of operating oil of a hydraulic cylinder; an operation amount data acquisition unit that acquires operation amount data of an operating device; a pump flow rate calculation unit that calculates a first pump flow rate indicating a flow rate of the operating oil discharged from a first hydraulic pump and a second pump flow rate indicating a flow rate of the operating oil discharged from a second hydraulic pump in a splitting state in which a passage is closed based on the cylinder pressure data and the operation amount data; and a pump control unit that controls the first hydraulic pump and the second hydraulic pump based on the first pump flow rate and the second pump flow rate.

Abstract: To provide a work machine which, in a configuration provided with a closed-circuit pump and an open-circuit pump, is capable of stabilizing respective pump operations of the closed-circuit pump and the open-circuit pump and of improving the mountability of the closed-circuit pump and the open-circuit pump. The present invention is provided with a closed circuit in which a closed-circuit pump and a boom cylinder are connected annularly, and an open circuit which has an open-circuit pump for making hydraulic fluid flow in from a reservoir and flow out and a connection passage capable of introducing hydraulic fluid into the closed circuit, wherein the closed-circuit pump is installed above the open-circuit pump.

Abstract: A control system for controlling a work machine including a working unit including elements and actuators that drives the elements includes: a first hydraulic pump and a second hydraulic pump each of which supplies operating oil to at least one of the actuators; and a control device that calculates a distribution flow rate of operating oil distributed to each of the actuators based on an operating state of the working unit and switches, based on the calculated distribution flow rate, between a first state in which the operating oil supplied from both the first hydraulic pump and the second hydraulic pump is supplied to the actuators and a second state in which the actuator to which the operating oil is supplied from the first hydraulic pump is different from the actuator to which the operating oil is supplied from the second hydraulic pump.

Abstract: A system and method for managing the temperature of a urea solution are thereby provided, in which air bubble formation in the urea solution caused by increases in the urea solution temperature is suppressed while thawing of the urea solution stored in the urea solution tank and used for NOx purification treatment is ensured, the concentration of the urea contained in the urea solution is accurately determined, and NOx is precisely reduced.

Abstract: A beverage production module includes a pump for delivering a fluid from a tank to an extraction chamber, a power source for the pump, and a controller for operating the pump and for controlling the voltage applied from the power source to the pump. The controller is adapted to operate the pump at a normal operation voltage (U3) and to operate the pump over a predefined time (T1,T2) at a reduced voltage level (U1, U2).

Abstract: A fluid pressure system includes an actuator, an operating valve, and a spool valve. The spool valve is connected to a pressure source and a tank by a pressure source line and a tank line, respectively, and connected to the actuator by a first movement line and a second movement line. The spool valve moves from a neutral position to a movement position by a moving amount corresponding to a pilot pressure outputted from the operating valve, the movement position being a position at which the spool valve allows the pressure source line to communicate with the first movement line and allows the second movement line to communicate with the tank line. A relief line branches off from the second movement line, and the relief line connects to a tank. A variable throttle valve is provided on the relief line.

Abstract: A hydraulic circuit for a transmission including a main pump and a sub pump is provided in which when the main pump and the sub pump are driven by an engine after it has been stopped for a long time, due to the internal pressure of a torque converter being low, a sufficient hydraulic pressure cannot be transmitted to a feedback port of a switching valve via a fifth oil passage; communication between a first port and a second port of the switching valve is cut off, and the oil discharged by the sub pump is therefore not supplied to a lubrication system via a sixth oil passage but is supplied via the path: second oil passage?first port of switching valve?fourth oil passage?first port and second port of second pressure regulating valve?torque converter.

Abstract: A valve subassembly includes a pump connection location, a tank connection location, and two constantly adjustable direction control valves each with first and second operating connection locations and an input connection location. A first valve group includes one direction control valve whose input is connected in parallel to two separate pump lines such that pressurized fluid is directed exclusively from the two pump lines to the control connection location. The two pump lines include a maximum of a first pump line and each remaining pump line is a second pump line. The maximum one first pump line is directly connected to the pump connection location in fluid terms, and a separate constantly adjustable pump valve is associated with each second pump line. Pressurized fluid is directed from the pump connection location via the pump valve into the associated second pump line.

Abstract: A hydraulic circuit for a construction machine is disclosed, which can prevent a loss of pressure during a combined work.

Abstract: A fluid pressure control device for a construction machine includes a first circuit system connected to the first pump; a second circuit system connected to the second pump; a switching valve having a normal position, a straight traveling position and a merging position where the working fluid of the branch section is merged into the second neutral passage; and an open/close mechanism configured to open/close the first neutral passage. In a case where at least one of the control valves, on which merging is required, on the downstream of the second traveling control valve is switched to a position other than the neutral position, by closing the first neutral passage by the open/close mechanism and switching the switching valve to the merging position, the working fluid of the first pump is merged into the working fluid of the second pump.

Abstract: To cope with a variety of flow rate balance required of two actuators flexibly in combined operations driving two actuators of high maximum demanded flow rates at the same time while suppressing the wasteful energy consumption caused by the throttle pressure loss in a pressure compensating valve, the arrangement is such that when the demanded flow rate of a boom cylinder 3a is lower than a prescribed flow rate, the boom cylinder 3a is driven only by hydraulic fluid delivered from a single flow type main pump 202 and when the demanded flow rate of the boom cylinder 3a is higher than the prescribed flow rate, the hydraulic fluid delivered from the single flow type main pump 202 and hydraulic fluid delivered from a first delivery port 102a of a split flow type main pump 102 are merged together and the boom cylinder 3a is driven by the merged fluids.

Abstract: The energy efficiency is increased by reducing the throttle/relief loss in the delivery flow of the hydraulic pump caused by the bleed-off control, while also making it possible to control the delivery pressure of the hydraulic pump according to the operation amount of the control lever unit and improving the operational performance. A controller 6 includes a target pump pressure setting unit 32 which calculates a target pump delivery pressure which increases with the increase in an operation amount signal from an operation amount detector 20A/20B based on the operation amount signal and a pump flow rate upper limit setting unit 33 which calculates a pump flow rate upper limit which increases with the increase in the operation amount signal based on the operation amount signal.

Abstract: A boom cylinder circuit is provided with a boom control valve for controlling supply and discharge of hydraulic oil to and from a boom cylinder, and a merge switching valve operable to be switched between a supply position at which hydraulic oil is suppliable from a first hydraulic pump to the boom control valve, and a blocking position at which a flow of hydraulic oil is blocked. A controller switches the merge switching valve to the blocking position when a combined operation of a boom lowering operation and an arm pushing operation is detected by pilot pressure sensors, and switches the merge switching valve to the supply position when only one of the boom lowering operation and the arm pushing operation is detected.

Abstract: A flow rate setting system of a working machine, includes: an attachment configured to be attached to the working machine; a control part configured to control a flow of hydraulic operation fluid based on a maximum flow rate of the hydraulic operation fluid being to be supplied to the attachment, the control part being mounted on the working machine; and a mobile terminal configured to communicate in wireless communication, the mobile terminal including: a first obtaining part configured to obtain identification information, the identification information being used for identifying the attachment; a second obtaining part configured to obtain the maximum flow rate of the attachment; and an output part configured to output the identification information and the maximum flow rate to the working machine in the wireless communication, the identification information being obtained by the first obtaining part, the maximum flow rate being obtained by the second obtaining part.

Abstract: A hydraulic circuit for a construction machine including a direction control valve group including direction control valves provided in tandem to a center bypass passage, a bleed-off valve provided to the center bypass passage downstream of the direction control valve group, and a control valve controlling an amount of pressure oil to be supplied to the direction control valve.