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 control system for a construction machine includes an electric lever operating device that outputs a command to a hydraulic actuator, a travel control lever device that outputs a command to a travel device, and a controller that outputs a drive command to a solenoid proportional valve that decompresses hydraulic fluid supplied from a pilot hydraulic source. The control system includes a machine body state judgment part that judges the state of the machine body based on an electric signal from the electric lever operating device and an operation amount of the travel control lever device and a dead zone calculation part that calculates a dead zone for the electric signal from the electric lever operating device based on the state of the machine body.

Abstract: The control system for the hydraulic construction machine includes: a hydraulic actuator; a work device driven by the hydraulic actuator; a hydraulic pump supplying a hydraulic fluid to the hydraulic actuator; a pump flow rate control section controlling the delivery flow rate of the hydraulic pump; a pump horsepower control section controlling the horsepower of the hydraulic pump; and a target surface distance acquiring section measuring or computing a target surface distance that is the distance between a construction target surface on which the work device works and the work device. The pump flow rate control section is configured to perform control such that as the target surface distance decreases, the delivery flow rate decreases, and the pump horsepower control section is configured to perform control such that as the target surface distance decreases, the horsepower of the hydraulic pump increases.

Abstract: A hydraulic system for a work machine includes a first hydraulic pump driving a swing hydraulic motor; a second hydraulic pumps driving a boom cylinder; a first pump displacement increase valve controlling a volume of the first hydraulic pump; a swing pilot pressure sensor detecting a swing operation amount; a boom raising pilot pressure sensor detecting a boom raising operation amount; and a controller controlling a control signal to the first pump displacement increase valve on the basis of the swing operation amount and the boom raising operation amount. The controller controls the control signal in such a manner that a delivery rate of the first hydraulic pump becomes higher as the swing operation amount is larger and an increasing rate of the delivery rate of the first hydraulic pump becomes lower as the boom raising operation amount is larger during a swing boom raising operation.

Abstract: Provided is a hydraulic excavator (1) that performs work by operating an arm (9) after moving a bucket (10) to a work start position. An operation determination section (81c) determines, based on an operation performed on an operation device, whether a front work device (1A) is engaged in a work preparation operation for moving the bucket to the work start position. When the operation determination section determines that the front work device is engaged in the work preparation operation at the time of operation of the operation device, an actuator control section (81) controls a bucket cylinder (7) such that the angle of a work tool with respect to a target surface coincides with a preset target angle (?TGT).

Abstract: A construction machine includes a control device having a reaction-force correction control section. When a difference between a target operator input and an actual operator input for a front member exceeds a preset range, the reaction-force correction control section executes correction to increase an operation reaction force to be applied by a reaction-force applying device to an operating unit operating an actuator driving the front member. When the difference falls within the range, the reaction-force correction control section executes correction to decrease the operation reaction force to be applied by the reaction-force applying device to the operating unit operating the actuator driving the front member.

Abstract: A hydraulic work machine is provided which can improve the finishing accuracy in a horizontally leveling work, a slope face shaping work and so forth by preventing sudden acceleration of an arm when the excavation load decreases suddenly. The hydraulic work machine includes an arm velocity-control valve device 22 capable of adjusting a meter-out opening of the arm cylinder independently of a first arm directional control valve 23. A controller 100 is configured to control, when correcting and increasing an operation amount instructed by the first arm directional control valve, the arm velocity-control valve device to decrease the meter-out opening of the arm cylinder in response to the increase of load pressure of the arm cylinder.

Abstract: Provided are a work point position computing section configured to compute the relative position of a work point set on a bucket with respect to an upper swing structure on the basis of posture information, a target surface setting section configured to set a target surface as a target of excavation work on the basis of design surface information, a primary operation determining section configured to determine which of operations of a boom and an arm is a primary operation as a main operation when the work point is moved along the target surface, and a recommended operation computing section configured to compute a recommended operation amount and a recommended operation direction of a secondary operation as another operation different from the primary operation in the operations of the boom and the arm according to an operation amount and an operation direction of the primary operation.

Abstract: A hydraulic excavator includes: a multijoint type front implement that is configured by coupling a plurality of driven members including a bucket; inertial measurement units that detect posture information about the plurality of driven members; and a calibration value computing section that computes calibration parameters used in calibration of detection results of the inertial measurement units; and a work position computing section that computes a relative position of the bucket to the machine body on the basis of the detection results of the inertial measurement units and the computation result of the calibration value computing section, and the calibration value computing section computes the calibration parameters on the basis of the detection results of the inertial measurement units in a plurality of postures of the front implement in which a reference point set on any of the plurality of driven members in advance matches a reference position.

Abstract: A hydraulic control system achieves a reduction in meter-out pressure loss in accordance with variation of a negative load acting on a hydraulic actuator. A hydraulic fluid discharged from the actuator flows through meter-out flow lines having variable restrictors. A load sensor detects the magnitude of a negative load applied to the actuator by an external force in the same direction as the operating direction of the actuator. A control device reduces the sum total of the opening areas of the variable restrictors in accordance with an increase in the magnitude of the negative load detected by the load sensor and the operation amount detected by the operation amount sensor when the load abnormality sensor does not detect any abnormality. When an abnormality is detected, it reduces the sum total of the opening areas to a predetermined value in accordance with the operation amount detected by the operation amount sensor.

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 work machine pump control system includes: a pump horsepower control valve (22) which causes a first urging force determining a limited horsepower (F) of a hydraulic pump and a second urging force due to a delivery pressure of the hydraulic pump to act on a spool in opposition to each other and which controls the pump flow rate such that it does not exceed the limited horsepower (F); a target pump flow rate computation section (42) computing a target pump flow rate based on an operation pressure (px) and a load pressure (py); a target horsepower computation section (41) which computes a required horsepower (Freq) corresponding to an operation pressure (px) from a relationship related to the operation pressure (px) and which computes a target horsepower (Ftar) based on the required horsepower (Freq); and a pump horsepower control section (35) which controls the pump horsepower control valve (22) such that the target pump flow rate (Qtar) is delivered with the limited horsepower (F) determined by the pump hor

Abstract: A control system for a construction machine stops an upper swing structure at a desired swing stop angle. A main controller sets a swing stop target angle at which an upper swing structure is to be stopped. A swing stoppability determination section reads an angle signal of the upper swing structure with respect to an undercarriage and an angle of a work implement, and determines whether the swing of the upper swing structure can be stopped at the swing stop target angle. A work implement is controlled in such a manner that an extension action of the work implement in a swing radial direction is prohibited or a contraction action of the work implement in the swing radial direction is executed in response to a signal that indicates whether the swing can be stopped and that is determined by the swing stoppability determination section.

Abstract: A hydraulic excavator includes: a hydraulic pump driven by power generated by an engine; a work device that operates by a plurality of hydraulic cylinders driven by power generated by the hydraulic pump; an actuator control section that controls the boom cylinder in such a manner that a tip end of a bucket is located on or above a target surface; a control point position calculation section that calculates a bucket claw tip position on the basis of angle sensors; and a power generator control section that imposes more limitations on output power ranges of the engine and the hydraulic pump when a distance between the claw tip position and the target surface is equal to or smaller than a threshold D than those when the distance between the claw tip position and the target surface is larger than the threshold D.

Abstract: The construction machine includes: a body (9, 10); work equipment (15) having a plurality of swingable work elements (8, 11, 12); a plurality of hydraulic actuators (5, 6, 7) for driving the work equipment; a plurality of ground angle sensors (13a to 13d) for detecting the ground angles of the work elements; and an excavation support device (400) including an information processing device (100). The information processing device includes: a load information acquiring section (130) for acquiring load information including the load direction in the swing center of at least one of the work elements according to signals from the ground angle sensors; and a working point position calculating section (150) for calculating the position of the working point of the work equipment according to the signals from the ground angle sensors and the load information from the load information acquiring section.

Abstract: Provided is a hydraulic control system for a construction machine, including: a control valve (31) for controlling supply and discharge of hydraulic fluid to and from an arm cylinder (4); an operation lever (6) for controlling the position of a spool of the control valve (31); a meter-out flow passage (34) for passing therethrough hydraulic fluid discharged from the arm cylinder; a variable restrictor (23a) provided in the meter-out flow passage; pressure sensors (41, 42) for detecting a magnitude of a negative load applied by an external force to the arm cylinder in a same direction as an actuation direction of the arm cylinder; and a controller (45) for reducing an opening area of the variable restrictor (23a) according to an increase in the magnitude of the negative load calculated with a detection value from the pressure sensors (41, 42).

Abstract: Disclosed is a hydraulic drive system capable of improving the fuel efficiency of a work machine by reducing the pressure loss and drag loss of a hydraulic pump. There are provided an electric motor M; a third pump P3 driven by the electric motor; a third pump hydraulic line L3 to which the delivered hydraulic fluid from the third pump is supplied; a third directional control valve V4 provided in the third pump hydraulic line, switch-operated by an arm operation device 19, and controlling the flow rate of the hydraulic fluid supplied to the arm cylinder 8 from the third hydraulic pump; and a controller 18 drive-controlling the electric motor, wherein the controller drives the third pump by the electric motor when a swing/arm combined operation is detected by pilot pressure sensors S6, S7, S10, S11.

Abstract: A motor-generator (27) is connected mechanically to an engine (21) and a hydraulic pump (23). The hydraulic pump (23) delivers pressurized oil to cylinders (12D) to (12F) in a working mechanism (12), a traveling hydraulic motor (25) and a revolving hydraulic motor (26). The revolving hydraulic motor (26) drives a revolving device (3) in cooperation with a revolving electric motor (33). An HCU (36) reduces outputs of the revolving electric motor (33), the revolving hydraulic motor (26), the boom cylinder (12D) and the like such that a ratio of a revolving speed of an upper revolving structure (4) and a movement speed of raising a boom (12A) is held to a ratio in a normal mode (NMODE) at the time of performing a compound movement of a revolving movement and a boom-raising movement in a low speed mode (LSMODE).

Abstract: The lifetime of an electrical storage device is prolonged by reducing a speed of at least relevant one of hydraulic actuators for a specific operation to be performed by a work machine. This hybrid work machine includes a limit control section. When at least one specific operation defined as predetermined one or more among a plurality of work operations performed by the hybrid work machine is performed under condition of a degree of tendency to deterioration of the electrical storage device becoming higher, the limit control section reduces a speed of at least relevant one of the hydraulic actuators at a rate preset for the specific operation depending on the degree of tendency to deterioration of the electrical storage device.

Abstract: A work machine including a specific actuator that supplies hydraulic fluid from a plurality of hydraulic pumps includes: first and second hydraulic pumps communicating with a first hydraulic actuator; a first control valve returning hydraulic fluid delivered by the first hydraulic pump to a tank; and a load detection section that detects a load on the first hydraulic actuator. A control valve drive section drives the first control valve such that a communication area between the first hydraulic pump and the tank is enlarged corresponding to an increase in the load on the first hydraulic actuator; and a flow rate control section, during supply of the hydraulic fluid from the first and second hydraulic pumps to the first hydraulic actuator, controls to reduce a delivery flow rate of the first hydraulic pump corresponding to an increase in the load on the first hydraulic actuator.