Abstract: Provided is a work machine with which an operator can easily perform semi-automatic excavating shaping work at an intended excavation velocity.

Abstract: A hydraulic work machine is provided in which left and right hydraulic motors are driven independently of each other by two hydraulic pumps and in which an anomaly of any of the left and right track devices can be detected with high accuracy. The hydraulic work machine includes a first pressure sensor 13 configured to detect a first pump pressure that is a delivery pressure of a first hydraulic pump 11 and a second pressure sensor 23 configured to detect a second pump pressure that is a delivery pressure of a second hydraulic pump 21.

Abstract: In a specific state where the raising operation of a boom 25 and the swing operation of an upperstructure 21 are performed at the same time to supply a hydraulic oil from a first pump 2 to a cylinder 7a through a first valve 6a, and to supply the same from a second pump 3 to a motor 7b through a second valve 6b, a controller 10 outputs the command current for opening a valve 13, and supplies a part of the hydraulic oil supplied to the motor 7b from the second pump 3 to the cylinder 7a through the third valve 6c when the motor 7b does not reach a steady swing state, and outputs a command current for closing the valve 13 when the motor 7b is in the steady swing state.

Abstract: To curb temperature rises in a control device for a supercharger and extend the life of the control device for the supercharger, a work vehicle includes a variable geometry supercharger with variable boost pressure, and a working device driven by pressure oil discharged from a working hydraulic pump, the work vehicle further including: a supercharger control device adapted to control the supercharger; a temperature detection device adapted to detect temperature of the supercharger control device; and a main control device adapted to limit at least one of maximum rotational speed of an engine and maximum vehicle speed of the work vehicle in case the temperature of the supercharger control device is above a predetermined temperature as compared to case the temperature of the supercharger control device is below the predetermined temperature.

Abstract: A counter balance valve (71L) is located between a directional control valve (23) and a hydraulic motor (32L) and provided on the way of a pair of supply/discharge lines (25A, 25B). The counter balance valve (71L) allows a spool (72L) to be displaced axially based on a pressure difference between the supply/discharge lines (25A, 25B). The counter balance valve (71L) includes a communicating passage (73L) for communicating the supply/discharge lines (25A, 25B) when the displacement of the spool (72L) exceeds a predetermined amount (XCM), based on a pressure difference between the supply/discharge lines (25A, 25B). The communicating passage (73L) is provided in the spool (72L) of the counter balance valve (71L).

Abstract: A hydraulic excavator (1) provided with a controller (40) having a machine control section (43) that executes machine control for moving a work implement (1A) following a predetermined condition at the time of operation of operation devices (45a, 45b, and 46c) includes a level-of-intervention input device (96) that is operated by an operator. The controller includes a correction amount calculating section (43m) that calculates a correction amount of a level of intervention indicating a degree of intervention by the machine control in an operation of the work implement instructed through operation of the operation devices, based on an operation amount of the level-of-intervention input device. The machine control section executes the machine control to intervene in the operation of the work implement instructed through the operation of the operation devices at a level of intervention corrected based on the correction amount calculated at the correction amount calculating section.

Abstract: To control a rate of increase of a delivery flow rate of a pump for a swing operation in response to a moment of inertia and an operation amount and to achieve both energy efficiency and operability with respect to the swing operation, a work machine including a swing structure 2 disposed on an upper portion of a track structure 1, a work implement 3 disposed in the swing structure 2, a swing motor 16, a hydraulic pump 22, a regulator 24, a directional control valve 31, and an operation device 34 further includes: a target maximum flow rate calculation section 53 configured to calculate a target maximum flow rate Qmax of the pump to correspond to a swing operation amount Ps; a flow rate rate-of-increase calculation section 55 configured to calculate a rate of increase dQ of a command flow rate of the hydraulic pump 22 on a basis of the moments of inertia of the swing structure 2 and the work implement 3 and the swing operation amount Ps; a command flow rate calculation section 56 configured to calculate a com

Abstract: A wheel loader configured to reduce a sudden change in vehicle speed caused by an erroneous determination of a raising operation of a lift arm is provided. A wheel loader 1 includes an engine 3, a variable displacement type HST pump 41, a variable displacement type HST motor 42 coupled to the HST pump 41 in a closed circuit, a hydraulic pump for working device 43, a forward/reverse selector switch 62 for switching a forward movement and a backward movement of a vehicle body, a depression amount sensor 610 that detects a depression amount of an accelerator pedal 61, a pressure sensor 73 that detects a discharge pressure Pa of the hydraulic pump for working device 43, and a controller 5. The controller 5 determines whether a specific condition to identify an upward movement of a lift arm 21 during a forward travel of the vehicle body based on a forward/reverse switching signal, the depression amount of the accelerator pedal 61, and the discharge pressure Pa detected by the pressure sensor 73.

Abstract: A controller includes a storage device that stores a load overflow reference value defined by a mutual relation between a load value of a work target object, a posture of a work implement, and a movement state of the work implement. The controller calculates the posture of the work implement, and calculates a physical quantity (for example, a swing speed) indicating the movement state of the work implement. The controller estimates whether or not the work implement has caused a load overflow during the transportation of the work target object on the basis of the reference value stored in the storage device, the calculated load value of the work target object, the calculated posture of the work implement, and the calculated physical quantity indicating the movement state of the work implement. When the controller determines that the load overflow has occurred, the controller makes a notification to that effect on a monitor.

Abstract: A work machine (1) includes a controller (40) having a notification control section (374) that exercises control as to whether to notify an operator of operation support information in accordance with a distance between a predetermined target surface, out of a plurality of discretionally set target surfaces, and a work implement (1A), the work machine including a current terrain profile acquisition device (96) that acquires a position of a current terrain profile, the controller including a target surface comparison section (62) that compares the position of the current terrain profile (800) with a position of the predetermined target surface (700) to determine a vertical position relationship between the current terrain profile and the predetermined target surface. The notification control section (374) changes content of the operation support information in accordance with a result of determination by the target surface comparison section.

Abstract: A construction machine that precisely enables derivation of the operation characteristics of hydraulic actuators in a high-velocity area with less calibration operation is provided. A controller (10) has a calibration mode in which the controller (10) derives operation characteristics (?(xs)) representing a relation among a spool position (xs) of a meter-in valve (8a1), an operation velocity (Va) of a hydraulic actuator (4a), and a differential pressure (?P) across the meter-in valve (8a1), and is configured to, in a case where the spool position (xs) of the meter-in valve (8a1) has changed in a direction to increase the opening area of the meter-in valve (8a1) in the calibration mode, output a command signal to increase the opening area of a bleed-off valve (8b1) to a bleed-off solenoid proportional pressure-reducing valve (8b2) as a command signal to reduce the differential pressure (?P).

Abstract: To provide a construction machine that can improve the energy efficiency in a leveling operation in which an arm crowding operation and a boom raising operation are performed simultaneously.

Abstract: A mode selecting device configured to select a work mode of a hydraulic excavator, a work determining section configured to determine whether work contents of the hydraulic excavator are work contents other than those of the selected work mode on the basis of a detection result of pilot pressure sensors, a minimum alarm region determining section configured to determine one of a plurality of minimum alarm regions preset on the periphery of the hydraulic excavator on the basis of a selection result of the mode selecting device and a determination result of the work determining section, and an alarm determining section configured to output an alarm signal to a buzzer when the relative position of an obstacle, the relative position being computed by an obstacle position calculating section, is inside an alarm region set so as to include the minimum alarm region determined by the minimum alarm region determining section.

Abstract: A work arm of a work machine includes a box-shaped structure including multiple plate members, a pair of bosses attached to opposing plate members, and a cylindrical boss coupling member coupling the pair of bosses together. Each boss includes a boss body section having a pin insertion hole through which a coupling pin is inserted and extending in an arrangement direction of the plate members, and a flange section extending outward from an outer circumferential portion of the boss body section and joined to a corresponding one of the plate members via a first weld. The boss body section includes a cylindrical outer body portion on an outer surface side of the box-shaped structure and a cylindrical inner body portion on an inner surface side of the box-shaped structure. The boss coupling member is joined, at both axial ends thereof, to respective ends of the inner body portions via second welds.

Abstract: A low idling controller (26A) switches an idling state flag from “clear” to “set” upon detecting a non-operation of an operating device (14). A rotational speed controller (26B) switches a rotational speed command from a set rotational speed by a rotational speed command device (27) to a low idling rotational speed based upon the idling state flag. At this time, an engine (8) drives in the low idling rotational speed lower than the set rotational speed. A gate controller (24) stops switching of an inverter (23) while the low idling controller (26A) is lowering a rotational speed of the engine (8).

Abstract: A load value W, which is a weight of a transportation target carried by a front work implement 12, is calculated based on a work load of a boom cylinder 16 of the front work implement 12, and on posture information which is information associated with a posture of the front work implement 12. A load threshold T used for determining whether to recalibrate a load measuring system is changed in accordance with a posture index value which is an index associated with the posture of the front work implement 12 and is obtained based on the posture information. Whether to recalibrate the load measuring system is determined based on the load value W and the load threshold T. A determination result is displayed on a display screen 30 to notify an operator of the determination result. In this manner, deterioration of measuring accuracy is more appropriately detectable regardless of variations of a posture of a front work implement of a work machine.

Abstract: It is an object of the present invention to provide a construction machine having a good engine starting property in a low temperature environment. The construction machine of the present invention includes: an electric pump having a delivery port connected to a line part of a pilot line, the line part connecting a pilot pump with a pilot control valve; a motor that drives the electric pump; and a temperature sensor that measures a temperature of a hydraulic working fluid delivered from the pilot pump. A controller starts driving of the motor in the case where a key switch is operated from a key OFF state to a key ON state and where the temperature of the hydraulic working fluid measured by the temperature sensor is lower than a predetermined temperature.

Abstract: A hydraulic drive system includes a swing directional control valve 81 and a third boom directional control valve 82 that are connected to a third hydraulic pump 33. Furthermore, the hydraulic drive system includes: a second auxiliary directional control valve 84 that is connected to the third hydraulic pump 33, and is connectable with a second special hydraulic actuator 64 for driving special attachments; and a first selector valve 96 that is connected to the third hydraulic pump 33 upstream of the second auxiliary directional control valve 84, and is connectable with an additional hydraulic pump 97. The first selector valve 96 switches the hydraulic fluid source of the second special hydraulic actuator 64 connected to the second auxiliary directional control valve 84 at least between the third hydraulic pump 33 and the additional hydraulic pump 97.

Abstract: An object of the present invention is to provide a construction machine that allows easy and accurate calibration of a pressure sensor and enables accurate control of hydraulic actuators.

Abstract: The safe operation assistance device 200 includes: a connecting destination detecting section 259 that detects and manages a connection state between the safe operation assistance device 200 and a connecting destination device; a unique information setting section 251 that sets unique information identifying a vehicle type of an own vehicle according to the connecting destination device; a positional information acquisition section 257 that acquires positional information of the own vehicle; an own vehicle information management section 252 that manages the positional information and the unique information of the own vehicle; an inter-vehicle communication section 255 that transmits the own vehicle information to other vehicle and acquires other vehicle information; and a risk determination section 254 that determines presence or absence of a collision risk between the own vehicle and the other vehicle using the own vehicle information and the other vehicle information.