Abstract: A hydraulic drive system for a hydraulic working machine sets a delivery pressure at a preset value upon raising a temperature of exhaust gas to a temperature needed for combustion of particulate matter by increasing a load to be applied to an engine. In a non-operation state, a variable restrictor is controlled by a controller and a delivery pressure control valve to increase a delivery pressure of a variable displacement hydraulic pump, so that the load is increased to raise the temperature of exhaust gas to the temperature needed for the particulate matter combustion. At this time, the controller controls the delivery pressure control valve such that a delivery pressure to be detected by a delivery pressure sensor will conform with a preset reference delivery pressure. The reference delivery pressure is set to a minimum pressure that can provide the exhaust gas with combustion heat.

Abstract: To rapidly stop an upperstructure even though relief pressure is lowered due to an abnormality in a hydraulic device included in a swing motor driving circuit while intending to stop the upperstructure when a predetermined delay time has passed since a swing operation tool is brought back to a neutral position, provided are: a first choke for controlling a parking brake to apply a braking force to a swing motor when a predetermined delay time has passed since the tool is brought back to a neutral position in a state where the tool is connected to a pilot pump; and an on-off valve and a second choke for controlling the parking brake to apply a braking force to the motor when a delay time shorter than the predetermined delay time has passed since the tool is brought back to the neutral position and disconnected from the pilot pump.

Abstract: A hydraulic driving device for a working machine surely prevents behavior of a single rod double acting cylinder not intended by an operator when discharge pressure of a main pump is raised to raise exhaust gas temperature to temperature required for burning particulate matter. A selector valve 160 interposed between a spool valve 61 and a rod chamber of a single rod double acting cylinder 51 and a section (a filter regeneration time actuation valve 122, a vehicle body controller 150) controlling the selector valve, are provided. A switch control section prevents a flow of oil directed from the rod chamber of the cylinder toward the spool valve by actuating the selector valve by a poppet of the selector valve when a by-pass cut valve 110 is controlled to increase a load of an engine 21 to a degree exhaust gas temperature reaches temperature required for burning particulate matter.

Abstract: Construction machinery that can achieve a great fuel reduction effect through an efficient use of recovered energy is provided. The Construction machinery includes at least two actuators 7 and 8, a main pump 3 that generates hydraulic energy for driving the actuators 7 and 8, flow control means 4 disposed between the main pump 3 and the actuators 7 and 8, an additional energy generating means 11 that generates energy to be added to the hydraulic energy, and a control means 20 that reduces hydraulic energy generated by the main pump 3 when the additional energy generating means 11 generates energy. The construction machinery further comprises changeover means 12d, 12e, and 12f that selectively change a location at which the energy from the additional energy generating means 11 is to be added according to the actuators 7 and 8. The control means 20 changes a reduction rate of the hydraulic energy generated by the main pump 3 depending on a specific actuator 7 or 8 to which the energy is to be added.

Abstract: A hydraulic drive device for a construction machine includes an engine stopping unit and a discharge rate control unit. The engine stopping unit stops the engine when a predetermined state of the construction machine has continued for a predetermined period of time. The discharge rate control unit controls a discharge rate control pressure being input to the regulator, when an exhaust emission control device performs regeneration control, or performs warm-up control, and the gate lock lever is in the open position.

Abstract: Disclosed is a hybrid construction machine that includes a control device and an auxiliary control device. The control device switches between a hydraulic/electric complex swing mode in which both the electric motor and the hydraulic motor are driven to drive the swing structure by using the sum of the torque of the electric motor and the torque of the hydraulic motor; and a hydraulic-only swing mode in which only the hydraulic motor is driven to drive the swing structure by using only the torque of the hydraulic motor. The auxiliary control device includes a monitoring controller that is connected to the control device and to the electric motor to monitor the temperature or electrical leakage in the electric motor as a substitute controller for the power control unit or the electrical storage device when the power control unit or the electrical storage device is removed due to a fault.

Abstract: A hydraulic drive device for a hydraulic excavator, includes: a first hydraulic pump; a first boom directional control valve and a second arm directional control valve which are connected in parallel to the first pump; a second hydraulic pump; and a second boom directional control valve and a first arm directional control valve which are connected in parallel to the second pump; wherein: the hydraulic drive device also includes: a third hydraulic pump; a third boom directional control valve connected to the third pump and controlling the flow of pressure oil supplied to a boom cylinder; and a third arm directional control valve connected in tandem with the third boom directional control valve and controlling the flow of pressure oil supplied to an arm cylinder.

Abstract: A hydraulic drive system realizes a jack-up operation without arrangement of a flow rate control valve and center bypass selector valve. The hydraulic drive system has first and second hydraulic pumps, first and second directional control valves for controlling boom cylinders, a third directional control valve for controlling the boom cylinders, and a third hydraulic pump for feeding pressure oil to the third directional control valve. A jack-up selector valve has a second select position where, when a pressure in bottom chambers of the boom cylinders is not higher than a predetermined pressure, feeding of pressure oil, which is delivered from the first hydraulic pump and second hydraulic pump, to rod chambers of the boom cylinders, is held permissible in association with switching of the second directional control valve and third directional control valve by a manipulation of a control device.

Abstract: An exhaust gas purification system for an engineering machine is capable of avoiding decreases in working efficiency during regeneration control by burning off a deposit of particulate matter from a filter efficiently during a work pause time. An operating section 17 of a display monitor 16 is used to set a work pause time and a work pause switch 13 notifies a vehicle body control unit 21 that the hydraulic excavator has entered a work pause state. In response, the vehicle body control unit 21 calculates the time required for a regenerating device to burn off the current amount of particulate matter deposited on the filter, and when the calculated time is longer than the preset work pause time, a regeneration controller 4a of an engine control unit 4 is activated, and a solenoid control valve 15 is switched to a closed position during the preset work pause time.

Abstract: Disclosed is a display device 5 for a work machine having an engine 9, a hydraulic pump 10 driven by the engine, a boom cylinder 3d, an arm cylinder 3e, a bucket cylinder 3f, and other actuators driven by a hydraulic fluid supplied from the hydraulic pump 10, and an operating device 6 for operating the actuators 3d, 3e, 3f. The display device 5 includes an idle state display section 50a for displaying an engine revolution speed N as no-manipulation period operating state information which is related to an engine load that is imposed while the operating device 6 is not manipulated. This makes it possible to inform an operator of the status of the engine load in an idle state for the purpose of prompting the operator to transition into a fuel-efficient state.

Abstract: Disclosed is a hybrid construction machine that includes a control device and an auxiliary control device. The control device switches between a hydraulic/electric complex swing mode in which both the electric motor and the hydraulic motor are driven to drive the swing structure by using the sum of the torque of the electric motor and the torque of the hydraulic motor; and a hydraulic-only swing mode in which only the hydraulic motor is driven to drive the swing structure by using only the torque of the hydraulic motor. The auxiliary control device includes a monitoring controller that is connected to the control device and to the electric motor to monitor the temperature or electrical leakage in the electric motor as a substitute controller for the power control unit or the electrical storage device when the power control unit or the electrical storage device is removed due to a fault.

Abstract: A hydraulic drive system for a working machine provides improved safety during forced regeneration. Upon input of a forced regeneration command signal from a forced regeneration switch, a controller detects non-operated states of all hydraulic actuators such as an arm cylinder arranged on a hydraulic excavator based on a lock detection signal from a gate lock detection switch, and also an attitude of a front working mechanism. The attitude is proper from the standpoint of safety. The detection is based on an arm angle signal from an arm angle sensor, a bucket angle signal from a bucket angle sensor and a boom pressure signal from a boom pressure sensor. Taking the detection of the non-operated states and proper attitude as conditions, the controller outputs control signals to a boosting proportional solenoid valve and flow-rate controlling, proportional solenoid valve to make a forced regenerator conduct forced regeneration.

Abstract: Provided is a hybrid construction machine capable of letting the operator immediately stop the swing structure by performing a stopping operation for ordinary construction machines even when the swing structure moves differently from the operator's will for some reason. The hybrid construction machine comprises: an inverter controller which outputs a PWM signal to an inverter and thereby controls the revolution speed of an electric motor; a first electric circuit including blocking means which blocks the PWM signal outputted from the inverter controller to the inverter in response to either an immobilization selection inputted through a gate lock lever switch or an OFF selection inputted through an ignition switch; and a second electric circuit including a swing brake solenoid valve which activates a swing brake in response to either the immobilization selection inputted through the gate lock lever switch or the OFF selection inputted through the ignition switch.

Abstract: Disclosed is a hydraulic drive system for a working machine, which enables to conduct forced regeneration continuously for a sufficient time. Based on an input of a lock detection signal S1 from a gate lock detection switch 40, a controller 50 detects that a gate lock lever 32 for controlling a gate lock on/off valve 33 is in a locked state, in other words, hydraulic actuators such as an arm cylinder 12 arranged on a hydraulic excavator 1 are all in non-operated states. Upon an input of a forced regeneration command signal So from a forced regeneration switch 53 in this detected state, control signals Cp,Cf are outputted to a boosting control valve 51 and regulator 52 to make a forced regeneration means (an arm cylinder control valve 27 and the regulator 52) conduct forced regeneration.

Abstract: An exhaust gas temperature raising processing system, which increases a load acting on an engine to raise the exhaust gas temperature, includes an electric assist motor connected to the engine and an inverter for adjusting a torque of the electric assist motor. It also includes a main controller having a first determination unit for determining whether or not an actuator control valve is in a non-feed state and a second determination unit for determining whether or not clogging has occurred on a filter of an exhaust gas purification system. When the non-feed state is determined by the first determination unit and clogging is determined to have occurred on the filter by the second determination unit, the main controller drives the electric assist motor to generate electric power such that a load acting on the engine is increased.

Abstract: Disclosed is a hybrid-type construction machine equipped with a swing hydraulic motor 27 and a swing electric motor 25 in combination to save energy, the construction machine ensuring high operability of a swing body 20 and providing high energy efficiency. In accordance with the amount of manipulation of a swing control lever 72, the construction machine changes a rate of a torque of the swing electric motor 25 with respect to that of the swing hydraulic motor 27. The construction machine also controls a relief pressure and the torque of the swing electric motor 25 in accordance with the amount of manipulation of a swing control lever 72, a pressure of the swing hydraulic motor 27, and a rotating speed of the swing electric motor 25.

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.