Abstract: This invention includes a hydraulic pump (9), a working implement (107) having a lift cylinder (13) driven by a hydraulic fluid supplied from the hydraulic pump (9), an operating device (104) for operating the working implement (107), a traveling motor (7) for driving wheels, and a main controller (100). When the lift cylinder (13) fails to operate despite an extending instruction being imparted to the lift cylinder (13) via the operating device (104), the main controller (100) reduces a limit value for an increase rate of a torque required in the traveling motor (7) to a value smaller than that applied when the lift cylinder (13) operates. With this configuration, occurrence of wheel slip during lifting of an object to be carried can be reduced.

Abstract: An object of the present invention is to provide a hydraulic control system for a work machine that is capable of reducing the loss caused by flow division while reducing a decrease in the speed of a hydraulic actuator due to a combined operation. The hydraulic control system for a work machine includes a first hydraulic actuator, one hydraulic pump, a second hydraulic actuator, and another hydraulic pump. The hydraulic control system further includes operating instruction detection means and pump flow control means. The operating instruction detection means detects that operating instructions are issued to the first hydraulic actuator and the second hydraulic actuator. The pump flow control means individually adjusts the delivery flow rate of the one hydraulic pump and the another hydraulic pump in accordance with operation amounts designated by the operating instructions for the first and second hydraulic actuators.

Abstract: An electrically driven working vehicle that requiring reduced power assistance from an electrical storage device is provided. The vehicle has an engine, a generator motor connected to the engine, a generator inverter for controlling the amount of power generated by the generator motor, a traveling motor for driving the vehicle, an electrical storage device connected to the generator inverter and the traveling motor, and a forward/reverse switching device for switching the traveling direction of the vehicle. The vehicle further includes a control device for outputting to the generator inverter an instruction to increase the amount of power generated by the generator motor when the voltage of the electrical storage device is equal to or lower than a maximum voltage level and a speed signal of the traveling motor given upon switching of the forward/reverse switching device is equal to or lower than a predetermined speed.

Abstract: When the total value of demanded hydraulic power and demanded traveling power is larger than the sum of the engine power that can be output by an engine (1) and of the discharge power that can be discharged by an electrical storage device (3), the actual power of a hydraulic pump (9) is increased from the value at the time of demand toward the demanded hydraulic power under the constraint of a predetermined limit. While the power of the hydraulic pump is being subjected to the predetermined limit, the actual power of the traveling motor is decreased from the value at the time of demand by a value smaller than the magnitude of the predetermined limit. This prevents worsening of ride comfort attributable to the distribution of power between the hydraulic pump and the traveling motor.

Abstract: The hybrid constructions machine has an engine rotation speed sensor 11A to detect a rotation speed NE of an engine 11, an engine state determination unit 20B to determine the state of output torque TE of the engine 11, a load torque estimation unit 20C to calculate load torque TP of a hydraulic pump 13, and an engine assistance limiting unit 20E to, when the rotation speed NE detected with the engine rotation speed sensor 11A is equal to or greater than a rotation speed N0, and the engine state determination unit 20B determines that the output torque TE of the engine 11 has not become minimum torque Tmin, or the load torque TP calculated with the load torque estimation unit 20C is lower than torque T1, limit motive-power assistance with the motor generator 12 to the engine 11.

Abstract: A hybrid wheel loader is provided, the hybrid wheel loader achieving high work efficiency even with a short supply of power to be output relative to a vehicle power requirement. The hybrid wheel loader includes a motor generator 6 connected to an engine (1), a hydraulic pump (4) connected to the motor generator, a hydraulic actuator (51, 52, 53) driven by hydraulic oil supplied from the hydraulic pump, a travel electric motor (9) for driving wheels (61), and an electrical storage device (11) connected to each of the motor generator and the electrical storage device via respective inverters (7, 10). When a total requirement power value is greater than a hybrid output upper limit value, either one of a hydraulic requirement power value Pf and a travel requirement power value Prun is limited according to an operation of the wheel loader to thereby set the total requirement power value to a value equal to, or less than, the hybrid output upper limit value.

Abstract: There are provided a work vehicle comprising a motor generator (6) driven by an engine, a hydraulic pump (4) driven by at least either of the motor generator and the engine, a work device (50) driven by hydraulic fluid from the hydraulic pump, a electric traction motor (9) driving wheels (61), an electrical storage device (11) connected to the motor generator and to the electric traction motor and charged electrically on the basis of a target SOC; and a control device (200) varying the target SOC for the electrical storage device (11) on the basis of total demanded power (Pf+Prun) of the hydraulic pump and the electric traction motor.

Abstract: [Problem] To provide a hybrid work vehicle which is simple in configuration, good in ease of mounting on a vehicle and capable of efficiently transmitting motive power. [Solution] The hybrid work vehicle includes: an engine (1); a hydraulic pump (4) which is driven by the engine; a work device (5) which is disposed at the front of the vehicle and performs work using the hydraulic pump as a drive source; a motor/generator (6) which generates electric power by use of the torque of the engine; and a travel drive device which causes the vehicle to travel by rotating and driving wheels by use of the electric power generated by the motor/generator. The hybrid work vehicle is steered while the vehicle bends by way of a center joint (15). The travel drive device includes: a plurality of electric motors (21 and 22); and a propeller shaft (8) which is linked with the plurality of electric motors and transmits motive power from the plurality of electric motors to the wheels.

Abstract: This invention includes a hydraulic pump (9), a working implement (107) having a lift cylinder (13) driven by a hydraulic fluid supplied from the hydraulic pump (9), an operating device (104) for operating the working implement (107), a traveling motor (7) for driving wheels, and a main controller (100). When the lift cylinder (13) fails to operate despite an extending instruction being imparted to the lift cylinder (13) via the operating device (104), the main controller (100) reduces a limit value for an increase rate of a torque required in the traveling motor (7) to a value smaller than that applied when the lift cylinder (13) operates. With this configuration, occurrence of wheel slip during lifting of an object to be carried can be reduced.

Abstract: There is provided an electrically driven working vehicle that needs reduced assisting power from an electrical storage device when accelerating subsequent to modulation and still obtains acceleration at least equivalent to that of torque converter vehicles. The electrically driven working vehicle has an engine 1, a generator motor 5 connected mechanically to the engine 1, a generator inverter 6 for controlling the amount of power generated by the generator motor 5, a traveling motor 7 for driving a vehicle body, an electrical storage device 3 connected electrically to the generator inverter 6 and to the traveling motor 7, and a forward/reverse switching device 103 for switching the traveling direction of the vehicle body.

Abstract: A construction vehicle control apparatus is provided including: a motor generator control unit (160) which, when regenerative electrical power generated by a motor (7) during regenerative braking surpasses acceptable charging electrical power of a capacitor (3), drives a motor generator (5) using the surplus electrical power; an engine controller (2) which detects the rotating speed of an engine (1); a motor control unit (180) which, if the rotating speed of the engine becomes larger than a second set value while the motor generator is being driven by the surplus electrical power, reduces regenerative torque generated by the motor; and a brake control unit (190) which, if the rotating speed of the engine becomes larger than the second set value while the motor generator is being driven by the surplus electrical power, increases regenerative torque generated by a hydraulic brake (30).

Abstract: [Problem] To provide a hybrid wheel loader capable of highly efficient and stable supply of motive power. [Solution] A hybrid wheel loader including: a front work machine (5) provided at the front of a vehicle; power sources including an engine (1) and an electric storage device; and a hybrid control device (20) which controls output of these power sources; characterized in that: a capacitor (11) is provided as the electric storage device; and the hybrid control device makes control to decrease a voltage of the capacitor in accordance with increase of energy held by the vehicle.

Abstract: When the total value of demanded hydraulic power and demanded traveling power is larger than the sum of the engine power that can be output by an engine (1) and of the discharge power that can be discharged by an electrical storage device (3), the actual power of a hydraulic pump (9) is increased from the value at the time of demand toward the demanded hydraulic power under the constraint of a predetermined limit. While the power of the hydraulic pump is being subjected to the predetermined limit, the actual power of the traveling motor is decreased from the value at the time of demand by a value smaller than the magnitude of the predetermined limit. This prevents worsening of ride comfort attributable to the distribution of power between the hydraulic pump and the traveling motor.

Abstract: There are provided an electric storage device (11), inverter devices (7, 10), a converter device (12) for converting the voltage of circuits to which the inverter devices (7, 10) are connected, a motor generator (6) for driving a hydraulic pump (4) using alternate current from the inverter device (7), a motor (9) for driving wheels (61) using alternate current from the inverter device (10), and a control device (200) for controlling the inverter devices (7, 10). When any of the devices necessary for supplying the current to the motor (9) has developed a failure, the control device (200) drives the motor (9) by getting another normal device to perform another process corresponding to the process that has been performed by the malfunctioned device before the failure. This makes it possible to continue travel movement even when part of a travel power supply system has developed a failure.

Abstract: A hybrid wheel loader is provided, the hybrid wheel loader achieving high work efficiency even with a short supply of power to be output relative to a vehicle power requirement. The hybrid wheel loader includes a motor generator 6 connected to an engine (1), a hydraulic pump (4) connected to the motor generator, a hydraulic actuator (51, 52, 53) driven by hydraulic oil supplied from the hydraulic pump, a travel electric motor (9) for driving wheels (61), and an electrical storage device (11) connected to each of the motor generator and the electrical storage device via respective inverters (7, 10). When a total requirement power value is greater than a hybrid output upper limit value, either one of a hydraulic requirement power value Pf and a travel requirement power value Prun is limited according to an operation of the wheel loader to thereby set the total requirement power value to a value equal to, or less than, the hybrid output upper limit value.

Abstract: A construction vehicle control apparatus is provided including: a motor generator control unit (160) which, when regenerative electrical power generated by a motor (7) during regenerative braking surpasses acceptable charging electrical power of a capacitor (3), drives a motor generator (5) using the surplus electrical power; an engine controller (2) which detects the rotating speed of an engine (1); a motor control unit (180) which, if the rotating speed of the engine becomes larger than a second set value while the motor generator is being driven by the surplus electrical power, reduces regenerative torque generated by the motor; and a brake control unit (190) which, if the rotating speed of the engine becomes larger than the second set value while the motor generator is being driven by the surplus electrical power, increases regenerative torque generated by a hydraulic brake (30).

Abstract: [Problem] To provide a hybrid work vehicle which is simple in configuration, good in ease of mounting on a vehicle and capable of efficiently transmitting motive power. [Solution] The hybrid work vehicle includes: an engine (1); a hydraulic pump (4) which is driven by the engine; a work device (5) which is disposed at the front of the vehicle and performs work using the hydraulic pump as a drive source; a motor/generator (6) which generates electric power by use of the torque of the engine; and a travel drive device which causes the vehicle to travel by rotating and driving wheels by use of the electric power generated by the motor/generator. The hybrid work vehicle is steered while the vehicle bends by way of a center joint (15). The travel drive device includes: a plurality of electric motors (21 and 22); and a propeller shaft (8) which is linked with the plurality of electric motors and transmits motive power from the plurality of electric motors to the wheels.

Abstract: [Problem] To provide a hybrid wheel loader capable of highly efficient and stable supply of motive power. [Solution] A hybrid wheel loader including: a front work machine (5) provided at the front of a vehicle; power sources including an engine (1) and an electric storage device; and a hybrid control device (20) which controls output of these power sources; characterized in that: a capacitor (11) is provided as the electric storage device; and the hybrid control device makes control to decrease a voltage of the capacitor in accordance with increase of energy held by the vehicle.

Abstract: A braking controller is equipped to provide braking force distribution of the required total braking force, to distribute the required total braking force by regeneration distribution. The regeneration distribution is required to be within a rear-wheel dominant range, in which the distribution ratio is inclined toward the rear-wheels when compared with an ideal distribution line that provides distribution enabling the front and rear wheels to simultaneously lock, as well as within a range that is not greater than a rear-wheel locking limit enabling the rear wheels to lock in relation to a road-surface friction coefficient upon braking. A rear-wheel braking force change ratio, which is a change ratio of the rear-wheel braking force with regard to a change of the front-wheel braking force associated with the change of the required total braking force, is required to always be positive.

Abstract: Provided is an actuator control system capable of suppressing vibrations during regeneration.