Abstract: In an electric drive system in which a battery is not connected to a DC bus, even when a load on a traveling electric motor increases suddenly, it is made possible to avoid such a situation that the DC bus voltage drops to a level equal to or lower than an operating voltage of an inverter and the inverter stops working. To this end, a DC bus voltage drop prevention device controls such that, when the voltage of the DC bus drops below a first threshold value, the output torque of the traveling electric motor is decreased according to an amount of decrease in the voltage of the DC bus, and when the voltage of the DC bus drops below a second threshold voltage lower than the first threshold voltage, the output torque of the traveling electric motor is decreased to zero or a value within a range of magnitude with which a work vehicle stays stationary on a level ground.

Abstract: Provided is a work machine that can suppress decrease in work efficiency while reducing the possibility of contacting a worker or a dump truck, etc. A movement range is set in advance so as to avoid entry of a worker or a dump truck, etc. into the set movement range. The work machine performs stop control with clearance for an obstacle having entered the movement range, but performs stop control with relatively small clearance (minimum clearance) for a movement range. Thus, the work machine can reduce the frequency of stopping a body or a work implement and suppress decrease in work efficiency. Since the work machine controls the body or the work implement to stop with clearance when the worker or the dump truck, etc. enters the movement range of the work machine, the work machine can reduce the possibility of contacting the worker or the dump truck, etc.

Abstract: Provided is a construction machine in which a pair of boss parts (17L, 17R) coupled via a boss pipe (18) are welded to a tip end of an arm (7), a coupling pin (16) is rotatably supported in bushes (20L, 20R) of the respective boss parts (17L, 17R), and brackets (8b) of a bucket (8) are coupled to opposite ends of the coupling pin (16). An inner pipe (25) is fitted onto the coupling pin (16) on an inner circumferential side of the boss pipe (18), and defines a grease passage (26) between the coupling pin (16) and the inner pipe (25). Left and right gaps between the boss pipe (18) and the inner pipe (25) are closed with side plates (27L, 27R), and a pair of grease chambers (28L, 28R) communicating with each other via the grease passage (26) are defined. A grease supply pipe (29, 30) has a base end welded to a center of an outer circumferential surface of the inner pipe (25) in an axis (C) direction, and a tip end opened in a left side plate (7L) of the arm (7), so that a nipple (33) is mounted to the tip end.

Abstract: It is made possible to prevent damage to hydraulic parts of a work machine due to a decrease in performance of a hydraulic fluid even when the hydraulic fluid of a hydraulic system is changed and the hydraulic fluid becomes a mixed oil in which a mineral oil and a biodegradable oil are mixed with each other. For this purpose, a storage device stores, in advance, oil change history information of the hydraulic fluid, oil kind determination values for determining whether the hydraulic fluid is either the mineral oil or the biodegradable oil or the mixed oil of the mineral oil and the biodegradable oil, and abnormality determination values for respective kinds of the hydraulic fluid. A controller checks whether the oil change history information includes oil change information for which oil kind determination has not been made.

Abstract: Provided is a technique for improving the cooling efficiency of a vehicle heat exchange system configured to cool a cooling liquid discharged from each of a plurality of heat sources.

Abstract: This invention provides a work vehicle in which operating switches are easy to operate even in a situation where the vehicle is shaken.

Abstract: An articulated-type front work implement has a boom, an arm, and a bucket that are driven members coupled to each other; a boom cylinder, an arm cylinder and a bucket cylinder that are hydraulic actuators each of which drives a corresponding one of the plurality of driven members on the basis of an operation signal; a plurality of operation members each outputting the operation signal to one of the hydraulic actuators; and a controller that outputs the operation signal to at least one of the plurality of hydraulic actuators or executes area limiting control of correcting the output operation signal such that the front work implement moves on a target surface preset for a work target of the front work implement or within an area above the target surface, and corrects the operation signal on the basis of information related to operation of the hydraulic actuator.

Abstract: Provided is a construction machine in which travel operability is not impaired when a combined operation is performed in which a single-rod hydraulic cylinder is driven during a travel operation. A hydraulic excavator includes a controller that controls the delivery direction and delivery flow rate of a closed-circuit pump, opens and closes a travel switching valve and an assist switching valve, and controls the delivery flow rate of the open-circuit pump, according to a travel operation lever and a work operation lever. The controller holds the assist switching valve in a closed position irrespective of whether or not the work operation lever is operated in a case where the travel operation lever is operated.

Abstract: The invention of the present application intends to provide a work machine that can ensure high operability by preventing abrupt actuation of an actuator and a shock to a machine body by use of a bleed-off function at the time of starting of the actuator and that can improve the energy-saving performance by reducing a bleed-off flow rate after the starting of the actuator. For this purpose, a controller opens a bleed-off valve at a timing at which an operation device is being operated and before a flow rate of a hydraulic pump starts increasing, and closes the bleed-off valve at a timing at which the operation device is being operated and after the flow rate of the hydraulic pump has started increasing.

Abstract: When a tilt in a right-and-left direction occurs in a cargo bed (9) being raised due to imbalance of excavated materials, the tilt is detected as a roll angle (?R), and it is determined whether the absolute value (|?R|) of the roll angle is not less than an imbalance determination value (?2) (S4). When the absolute value is not less than the imbalance determination value (?2) (Yes in S4) and the roll angle (?R) is positive (the cargo bed (9) is rising to the right) (Yes in S8), an oil supply amount (VL) to a hoist cylinder (11) on the left side is increased, and an oil supply amount (VR) to a hoist cylinder (12) on the right side is decreased (S9). When the roll angle (?R) is negative (the cargo bed (9) is rising to the left) (No in S8), the oil supply amount (VL) on the left side is decreased, and the oil supply amount (VR) on the right side is increased (S10).

Abstract: A work vehicle including a drive device (10) having an internal combustion engine (12) for driving a vehicle body (1) has: a first tank (32) that is disposed in front of or behind the drive device, and stores fuel (9) to be supplied to the internal combustion engine; a second tank (34) that is disposed below the drive device so as to be separated from the first tank by a predetermined distance, and stores the fuel to be supplied to the internal combustion engine; a first storage amount detection part (70) that is disposed in the first tank, and detects an amount of the fuel stored in the first tank; and a second storage amount detection part (80) that is disposed in the second tank, and detects an amount of the fuel stored in the second tank.

Abstract: In a case of a normal operation, a battery controller (22) assumes a normal operation mode and permits charging and discharging of a battery module (21). Upon receiving a discharge command from a vehicle body controller (17) for completely discharging the battery module (21), the battery controller (22) assumes a discharge mode to discharge the battery module (21) to reach a safe voltage level and store discharge information. Upon reading out the discharge information, the battery controller (22) assumes a discharge prohibition mode to prohibit charging and discharging of the battery module (21).

Abstract: The present invention provides a working machine that makes it possible to alert its operator to cautions properly without obstructing the view of the operator. The working machine includes a cab for its operator to ride in, a projection device that projects image light to form an image of cautions to an operator who operates the working machine, a display unit that displays image light projected by the projection device, state detection element to detect a state of the working machine, and a controller that controls the projection device so that a manner of displaying the cautions on the display unit will change depending on the state of the working machine detected by the state detection element.

Abstract: The object of the present invention resides in provision of a construction machine in which a hydraulic cylinder can be driven in a high efficiency by an accumulator. To this end, the construction machine including: a hydraulic cylinder; a first accumulator that accumulates return fluid from the hydraulic cylinder with a first set pressure; a tank that stores hydraulic fluid therein; a first hydraulic pump that delivers the hydraulic fluid sucked from the tank; a hydraulic actuator that is driven by the first hydraulic pump; and a second accumulator that accumulates return fluid from the hydraulic actuator with a second set pressure, includes a first control valve placed in a first hydraulic line that connects the first accumulator and the hydraulic cylinder to each other, and a second control valve placed in a second hydraulic line that connects the second accumulator and the hydraulic cylinder to each other. The second set pressure is set to a value higher than that of the first set pressure.

Abstract: Provided is a work machine capable of achieving both low fuel consumption and ensuring of workability. The work machine is configured to, in a state where an output of an engine or hydraulic pump has increased to an increase threshold (S12: Yes) with the rotational speed being at a first rotational speed (S11: Yes), raise the rotational speed from the first rotational speed to a second rotational speed (S13); in a process of raising the rotational speed to the second rotational speed, output, to a regulator, a signal instructing reduction in the discharge rate (S14) so as to keep the output of the engine or hydraulic pump constant; and after the rotational speed has reached the second rotational speed, output, to the regulator, a signal instructing increase in the discharge rate (S16) so as to make the output of the engine or hydraulic pump have a value corresponding to a request load.

Abstract: A work machine includes: a hydraulic actuator that is driven by a hydraulic fluid from a hydraulic pump; an open-center directional control valve that is arranged on a center bypass line, and controls a flow of the hydraulic fluid to be supplied to the hydraulic actuator; a CB cut valve arranged between a directional control valve and a hydraulic working fluid tank on the center bypass line; and a machine controller that controls an opening of the CB cut valve. The machine controller restricts the opening of the CB cut valve when operation on the hydraulic actuator is in a fine operation state in which the operation on the hydraulic actuator is within a predetermined range representing a region of fine operation, and the fine operation state is continued longer than a predetermined period, and fully opens the CB cut valve otherwise.

Abstract: Each time clogging of a filter (5) of an air cleaner is determined on the basis of intake negative pressure of an engine (2), and the air filter (5) is cleaned, an accumulated value of operating time of the engine (2) from previous cleaning until clogging is determined is taken as a cleaning interval (S), and sequentially measured. A plurality of stages are previously set by classifying a minimum value and a maximum value of the cleaning interval (S), and the measured cleaning interval (S) is added to the stage to which the measured cleaning interval (S) is to belong, among the stages. A histogram in which an axis of abscissas is taken as the stage, an axis of ordinates is taken as frequency of the cleaning interval (S) is constructed, and an approximate straight line (L2) illustrated by a solid line is obtained by approximating a characteristic line (L1) of the histogram illustrated by a dotted line to a straight line.

Abstract: A plus-side main connection line (27) connects electrical equipment (21), (22) to a plus terminal (26A) of a battery (26). A plus-side isolating switch (28) is provided in the plus-side main connection line (27) to connect or disconnect the electrical equipment (21), (22) and or from the plus terminal (26A) of the battery (26). A plus-side auxiliary connection line (30) connects a urea SCR controller (25) to the plus terminal (26A) of the battery (26) in a position upstream of the plus-side isolating switch (28). A minus-side main connection line (32) connects a minus terminal (26B) of the battery (26) to ground. A minus-side isolating switch (33) is provided in the minus-side main connection line (32) to connect or disconnect the minus terminal (26B) of the battery (26) and or from ground.

Abstract: A wheel loader includes a lift arm, bucket, a lift cylinder that rotates the lift arm, a hydraulic force detection unit that detects a hydraulic force of the lift cylinder, an arm angle detection unit that detects a rotation angle of the lift arm, and a controller that calculates a weight of the load. A hydraulic force measurement unit measures a hydraulic force with the rotation angle of the lift arm within a predetermined measurement angle range; and a hydraulic-force-change-rate calculation unit calculates a change rate of the hydraulic force with respect to the rotation angle of the lift arm, and then calculates a new hydraulic force change rate within the measurement angle range. The controller corrects an error of the weight of the load occurring due to the inclination angle of the body on the basis of the new hydraulic force change rate calculated by the hydraulic-force-change-rate calculation unit.

Abstract: A construction machine is provided that can cause each hydraulic actuator to accurately operate according to operation by an operator in combined operation in which a hydraulic fluid of a hydraulic pump is subjected to flow dividing and is supplied to plural hydraulic actuators. A controller 10, in a case of determining that combined operation is being carried out, controls a regulator 7a in such a manner that the delivery flow rate of a hydraulic pump 7 becomes larger than the total target flow rate of plural hydraulic actuators 4a, 5a, and 6a, and controls the respective opening amounts of plural directional control valves 8a1, 8a3, and 8a5 in such a manner that the difference between the respective target flow rates of the plural hydraulic actuators and the respective inflow flow rates of the plural hydraulic actuators sensed by velocity sensors 12 to 14 becomes small.