Abstract: A hybrid construction machine has an electric motor for driving the swing structure, and the electric motor is prevented from becoming incapable of generating torque due to a low energy state or an overcharged state of an electricity storage device. A swing-mode selector switch 77 which is manually operated switches between a hydraulic/electric combined swing mode for driving the swing structure by driving both the electric motor and a hydraulic motor and a hydraulic solo swing mode for driving the swing structure by driving only the hydraulic motor. For a normal operation, the swing mode is initially set in the hydraulic/electric combined swing mode. For a specific operation, the operator switches the swing-mode selector switch from a hydraulic/electric combined swing position to a hydraulic solo swing position.

Abstract: The present invention includes a hydraulic brake device 4, 5 that generates a braking force corresponding to an operation of a brake pedal 1 performed while the vehicle is traveling, a brake lock means 6 for applying a hydraulic lock on the hydraulic brake device 4, 5 and releasing the hydraulic lock, a brake pedal operation detection means 22 for detecting an operation of the brake pedal 1, and a control means 10 for controlling the brake lock means 6 so as to apply the hydraulic lock on the hydraulic brake device 4, 5 upon detecting via the brake pedal operation detection means 22 a predetermined depressing operation of the brake pedal 1.

Abstract: A hydraulic drive system designed so that while maintaining intact a structure of a relief valve having a shockless function, the drive unit hydraulic drive system facilitates changing a driving pressure or braking pressure of a hydraulic swing motor and hence, changing a maximum driving torque or braking torque of the hydraulic swing motor. Inside a swing motor unit is arranged a first swinging relief valve provided with a shockless function to limit a driving pressure or braking pressure of the hydraulic swing motor in order to prevent the pressure from exceeding a first setting pressure. Also, a second swinging relief valve is provided for limiting the driving pressure or braking pressure of the hydraulic swing motor in order to prevent the pressure from exceeding a second setting pressure that is lower than the first setting pressure.

Abstract: There are provided: control valves 22-24 that control flow of pressure oil from the hydraulic source 21 to the hydraulic actuators 15-17; electric lever devices 51-53 that output electrical operation signals, which are drive instructions for the hydraulic actuators 15-17, in correspondence to lever operation; and a control unit 25-30 and 50 that controls the control valves 22-24 in correspondence to the operation signals. When the determination unit determines that an operation signal is not within the normal range, the hydraulic actuators 15-17 are allowed to be driven with flow of pressure oil to the hydraulic actuators 15-17 limited more significantly than in a case where it is decided that an operation signal is within the normal range.

Abstract: A reduction gear is mounted on a revolving frame, and an electric motor having an electric motor shaft is disposed on the reduction gear. A hydraulic motor having a shaft is disposed on an upper side of the electric motor. A shaft insertion hole through which an upper end side of the electric motor shaft is inserted is provided in a lid portion of an electric motor casing. A male spline portion provided on the hydraulic motor shaft is spline-coupled to a female spline portion provided on the electric motor shaft. A bearing is provided between the shaft insertion hole and the electric motor shaft, and a pressure tight seal is provided by being located upwardly of the bearing. Hence, spline coupling portions of the female spline portion and the male spline portion are constantly lubricated by making use of drain oil which has leaked from the hydraulic motor.

Abstract: A hybrid construction machine is capable of performing satisfactory operations even when trouble occurs that disables the electric motor from outputting torque. The hybrid construction has both a hydraulic motor and an electric motor driving the swing structure and a controller for switching between a hydraulic/electric hybrid swing mode (using both the hydraulic motor and the electric motor) and a hydraulic-alone swing mode (using only the hydraulic motor). The switching is executed while achieving satisfactory operability and performance in each mode. Normally, an energy saving operation is performed in the hydraulic/electric hybrid swing mode. When the electric amount of an electricity storage device has gone out of a prescribed range or an abnormality has occurred in an electric system (e.g., failure of an inverter), the swing mode is switched to the hydraulic-alone swing mode so that driving with normal braking torque is possible by the hydraulic motor alone.

Abstract: A control system for a work vehicle includes: a negative-type parking brake device that starts operating in response to a parking brake instruction; an output device that outputs the parking brake instruction; a service brake device that operates in response to an operation of a brake pedal by an operator; and a brake control device that operates the service brake device regardless of a pedal operation by the operator when the parking brake instruction is output from the output device.

Abstract: A pedal lock control device for work vehicle includes: a motor driving device that drives a travel hydraulic motor in response to an operation amount of a travel pedal; a locking device that locks the travel pedal in a state of being operated; an instruction device that instructs lock and unlock of the travel pedal by the locking device upon an operation by an operator; a first detection device that detects a first signal change according to an unlock operation which is an operation that reflects an intention of an operator to release the locking device and is other than an unlock operation by the instruction device; a second detection device that detects a second signal change according to an unlock operation which is an operation that reflects an intention of an operator to release the locking device and is other than the unlock operation by the instruction device, with the second signal change being different from the first signal change; and a lock control device that unlocks the locking device when an un

Abstract: A pedal lock control device for work vehicle includes: a motor driving device that drives a travel hydraulic motor according to an operation amount of a travel pedal; a locking device that locks the travel pedal in a state of being operated; an instruction device that instructs lock and unlock of the travel pedal by the locking device upon an operation by an operator; a lock intention detection device that detects an intention of an operator to permit lock of the travel pedal; and a lock control device that locks the travel pedal by the locking device when an intention of the operator to permit lock is detected by the lock intention detection device and lock of the travel pedal is instructed by the instruction device.

Abstract: The present invention includes a hydraulic brake device 4, 5 that generates a braking force corresponding to an operation of a brake pedal 1 performed while the vehicle is traveling, a brake lock means 6 for applying a hydraulic lock on the hydraulic brake device 4, 5 and releasing the hydraulic lock, a brake pedal operation detection means 22 for detecting an operation of the brake pedal 1, and a control means 10 for controlling the brake lock means 6 so as to apply the hydraulic lock on the hydraulic brake device 4, 5 upon detecting via the brake pedal operation detection means 22 a predetermined depressing operation of the brake pedal 1.

Abstract: A rotational speed pickup 71 (traveling speed detection means), a hydraulic pressure sensor 72 (traveling operation detection means), a hydraulic pressure sensor 73 (drive status detection means), and a voltage sensor 74 (transmission shift position detection means) detect parameters regarding the traveling state of a hydraulic traveling vehicle. A control unit 80, a solenoid proportional valve 81, an engine control system 82, and a motor regulator 33 determine the operating state of the hydraulic traveling vehicle based on the parameters regarding the traveling state, and control the equivalent displacement of the traveling system including a hydraulic traveling motor 14 and the maximum flow rate supplied to the hydraulic traveling motor 14 according to the result of determination. The pump flow rate and motor displacement are controlled according to the traveling state in this way, thereby ensuring favorable traveling performance without degrading the fuel efficiency.

Abstract: To provide an engine control system for a construction machine, which can decrease a consumption of energy to be required for the reduction of an engine lag-down that occurs upon a sudden increase in load, such as upon quick manipulation of a control device, is provided with a load condition detecting unit, a charge amount detecting unit, a boost pressure sensor, and a determination processing unit. The load condition detecting unit includes a manipulation stroke detector for detecting that a control device has been fully manipulated, and also, a first computation unit of a controller. The charge amount detecting unit can detect an amount of charge in a capacitor. The determination processing unit includes a determination processing unit of the controller.

Abstract: The present invention provides an information management system suitable for a construction machine, which drives a solenoid valve separately from normal control to thereby make it possible to perform failure diagnosis for the solenoid valve and each sensor easily and with satisfactory accuracy. A controller has a failure diagnosis mode selected by a control panel of a display device. When the failure diagnosis mode is selected by the control panel and instructions for failure diagnosis related to a specific solenoid valve of a plurality of solenoid valves are given, the controller outputs a failure diagnosis drive signal to the specific solenoid valve, inputs an output value from a sensor related to the specific solenoid valve among a plurality of sensors, and displays, based on the output value from the specific sensor, information as to whether the specific solenoid valve and the specific sensor are normal on a display device.

Abstract: Provided is a hybrid construction machine (driving the upper swing structure using a hydraulic motor and an electric motor together) capable of regenerating the energy of the upper swing structure in deceleration or stopping into electric power and using the regenerated electric power for assisting the driving of the upper swing structure, while also being capable of securing satisfactory operational feeling and operation capability even when the electric motor does not operate. When the electric motor is not driven, a controller controls a hydraulic circuit system (specifically, a swing direction/flow rate control valve, a center bypass cut valve and a regulator) so as to increase output torque of the hydraulic motor by an amount corresponding to torque to be compensated for the non-driving of the electric motor compared to cases where the electric motor is driven.

Abstract: A hybrid construction machine drives the upper swing structure using a hydraulic motor and an electric motor together and is capable of regenerating the energy of the upper swing structure in deceleration or stopping into electric power and using the regenerated electric power for assisting the hydraulic motor for driving the upper swing structure. The opening area characteristics of a meter-out restrictor and a bleed-off restrictor of a swing directional control valve are set to become larger than for construction machines driving the upper swing structure with the hydraulic motor alone. Torque of the electric motor is controlled so that the total sum of the actual torque occurring in the hydraulic and electric motors in deceleration or acceleration of the hydraulic motor equals the torque occurring when the opening area of the meter-out restrictor or the bleed-off restrictor is set at the prescribed opening area.

Abstract: [Object] Motorization of a running gear of a construction machine traveling on wheels is realized without enormous increases in vehicle-body dimensions and costs. [Solution Means] A wheeled excavator 41 includes travel wheels 10, 11 installed in a vehicle body, an engine 3, a running motor-generator 15, an inverter 21 and a battery 22 which are electrically connected to the motor-generator 15, a hydraulic pump 4 driven by the engine, and a power transmission mechanism which transmits power among the engine 3, the wheels 10, 11, the running motor-generator 15, and the hydraulic pump 4. A clutch 23 which connects and disconnects the power transmission between the engine 3 and the wheels 10, 11 is provided in the power transmission mechanism. In a required area on the vehicle body, a clutch switching means is mounted for switching the clutch 23 to a disengaged state during a level road run and to an engaged state during a downhill run.

Abstract: A hydraulic system for a working machine is provided in which when heavy load fine speed operation work is performed using hydraulic cylinders as hydraulic actuators, and deterioration of fuel consumption can be prevented by reducing energy loss and improving fine speed operability. A center bypass cutoff valve 41 is disposed downstream of a center bypass line 26, and pressure sensors 42, 43, a controller 44, and a solenoid valve 45 provide control such that, when operating means 16 corresponding to a boom cylinder 5 (specific hydraulic actuator) among a plurality of operating means 18-21 is operated to supply a hydraulic fluid to a cylinder chamber 5a of the boom cylinder 5 in a load retaining side, the center bypass cutoff valve 41 is actuated and a fluid delivery pressure of a first hydraulic pump 2 is increased to be higher than a load pressure of the boom cylinder 5.

Abstract: A motor control device for construction machinery includes a hydraulic pump; a hydraulic motor driven by pressure oil from the hydraulic pump; a control valve that controls a flow of the pressure oil from the hydraulic pump to the hydraulic motor; a pair of main conduit lines that connect the hydraulic motor and the control valve on a delivery side and a return side thereof; an operation member that operates a spool of the control valve to either a neutral position that does not allow the pressure oil for driving from the hydraulic pump to pass through control valve to the hydraulic motor or a non-neutral position that allows the pressure oil for driving to pass through the control valve to the hydraulic motor; a braking pressure generating device that generates braking pressure in the main conduit lines on the return side in a state where the spool of the control valve is positioned in the neutral position as a result of being operated by the operation member, the braking pressure opposing rotation of the hy

Abstract: A working fluid cooling control system has a controller 100 that receives inputs signals from a traveling motor speed pickup 101, a pressure sensor 102, a signal receiving line 103a of an option selecting switch 103 and a temperature sensor 104. The controller performs predetermined arithmetic processing and controls proportional solenoid valves 105 and 106. The pressures controlled by the solenoid valves are compared with positive control command pressures in shuttle valves 109 and 110. In this way, in the case of an operation pattern corresponding to a rise in temperature of the working fluid, minimum tilting angles of hydraulic pumps 11 and 12 are increased to increase an average flow rate of the working fluid passing through an oil cooler 40, thereby increasing an average heat discharge amount and reducing an equilibrium temperature of the working fluid.

Abstract: A contamination level determination system for hydraulic oil is provided with a pilot filter arranged in a line of a hydraulic circuit of a hydraulic working machine to remove, from the hydraulic oil, foreign matter of particle sizes that may cause an operation failure of the hydraulic working machine. A first light-blocking sensor senses passage of foreign matter on an upstream side of the pilot filter. A second light-blocking sensor senses passage of foreign matter on a downstream side of the pilot filter. An onboard controller unit functions to determine a frequency of sensing of foreign matter by the first light-blocking sensor, to determine a frequency of sensing of foreign matter by the second light-blocking sensor, and to determine a contamination level on the upstream side of the pilot filter on the basis of results of the determinations from both sensors.