A hydraulic control device includes: a recovery oil passage; a regenerative motor that rotates an output shaft of an engine in response to a supply of the hydraulic fluid and is driven to rotate by rotation of the output shaft of the engine; a regenerative oil passage for guiding return oil from a boom cylinder to the regenerative motor without passing the return oil through the recovery oil passage; a coupling oil passage that couples the recovery oil passage and the regenerative oil passage to each other; and a regeneration-side check valve that is provided on the coupling oil passage, and allows the hydraulic fluid to flow from the recovery oil passage toward the regenerative motor, and moreover restricts the hydraulic fluid from flowing from the regenerative motor toward the recovery oil passage.

A work vehicle 1 includes a display unit 51 of a rechargeable work vehicle 1, and a display unit controller 53 configured to reduce a brightness of the display unit 51 during charge of the work vehicle 1, compared with that during operation of the work vehicle 1.

A hybrid power train system for a tractor scraper is provided. The hybrid power train system may include a primary power source coupled to a first set of traction devices, a generator coupled to the primary power source, a first electric motor coupled to a second set of traction devices, an inverter circuit coupled to the generator and the first electric motor, an energy storage device coupled to the inverter circuit, and a controller operatively coupled to the inverter circuit. The controller may be configured to engage a first operation mode enabling electrical energy, supplied by the generator and the first electric motor, to be stored in the energy storage device, and engage a second operation mode enabling electrical energy, stored in the energy storage device, to be supplied to the first electric motor to drive the second set of traction devices.

A power transmission device includes an input shaft, an output shaft, a gear mechanism, an energy-generating motor, a first clutch, and a locking device. The energy storage unit is configured to store the energy generated by the energy-generating motor. The gear mechanism includes a planetary gear mechanism, which includes a first rotation element, a second rotation element, and a third rotation element, which are mutually different. The first clutch is provided in the power transmission route between the engine and the first rotation element. The locking device locks or releases the second rotation element. The energy-generating motor is connected to the third rotation element. A controller locks the second rotation element, converges the rotation speeds of two rotation shafts in the first clutch to cause the first clutch to engage, and rotates the energy-generating motor using drive power from the engine to thereby accumulate energy in the energy storage unit.

Provided is hybrid construction machine that can charge/discharge an electrical storage device appropriately and can suppress stop of an engine accompanying sharp increase of a load. The present invention includes a hybrid controller 22 that controls power of a hydraulic pump 17 and electric power of an inverter 15 in response to storage battery characteristics of the electrical storage device 16, and an output command unit 22F of the hybrid controller 22 is configured to control at least either one of the power of the hydraulic pump 17 and the electric power of the inverter 15 on the basis of at least either one of electric current or voltage of the storage battery characteristics and at least either one of temperature or a state of charge of the storage battery characteristics.

A work vehicle 1 includes a display unit 51 of a rechargeable work vehicle 1, and a display unit controller 53 configured to reduce a brightness of the display unit 51 during charge of the work vehicle 1, compared with that during operation of the work vehicle 1.

The present disclosure relates to a power supply device for hybrid construction machinery, and more particularly, to a power supply device for hybrid construction machinery, which is capable of reducing engine loads and facilitating improvement of engine efficiency by excluding a starting motor used in general hybrid construction machinery and an alternator for charging a battery from hybrid construction machinery, such as a hybrid excavator or vehicle, which commonly uses an engine and an electric motor as a power source and includes an electric energy storage device, and a method for the same.

At the time of starting up an engine (9) using an assist motor generator (10), a main controller (28) lowers a lower limit value in a charge/discharge range of an electricity storage device (19) from a first lower limit value (min1) to a second lower limit value (min2) through an energy management control part (28B). The main controller (28) heightens the lower limit value in the charge/discharge range of an electricity storage device (19) from the second lower limit value (min2) to the first lower limit value (min1) when the start of the engine (9) is completed. Further, the main controller (28) displays engine stop prohibition information on a display device (30) when the start of the engine (9) is completed and when an SOC of the electricity storage device (19) falls below the first lower limit value (min1).

The object of the present invention is to provide a hybrid construction machine that can quickly warm up an electrical storage device and can improve the service life of the electrical storage device. This hybrid construction machine is equipped with: a prime mover (1); an electric motor that supplements the power of the prime mover (1) and generates electric power; an electrical storage device (8) that transmits power to and receives power from the electric motor; a warm-up circuit (25) that circulates a heating medium heated by waste heat from the prime mover (1) or the electric motor, or by a heater (40), to the vicinity of the electrical storage device (8); a control device that controls charging/discharging of the electrical storage device (8) and circulation of the heating medium of the warm-up circuit (25); and an outside air temperature measurement device that measures the outside air temperature. The control device executes warm-up operation by means of the heating medium, determines whether or not to execute charging/discharging of the electrical storage device (8) for the purpose of the warm-up operation in response to the outside air temperature measured by the outside air temperature measurement device, and conducts warm-up operation in which the warm-up operation by charging/discharging of the electrical storage device (8) is effected simultaneously.

A battery-operated work machine is provided which can perform a work while avoiding such a situation that the work machine cannot reach charging equipment. When the remaining capacity of a battery becomes lower than a first threshold value set in advance, a controller controls an inverter such that the revolution speed of an electric motor is kept at a target revolution speed and controls a first notification device to operate, and besides switches a traveling motor to a travel first speed side, in which the displacement volume is a large volume, irrespective of an input from a traveling mode instruction device, when the remaining capacity of the battery becomes lower than a first threshold value set in advance.