Hitachi Construction Machinery Tierra Co., Ltd.

Hitachi Construction Machinery Co., Ltd.

Hibachi Construction Machinery Tierra Co., Ltd.

Kiwamu Takahashi

Yoshifumi Takebayashi

Kazushige Mori

Yasutaka Tsuruga

Natsuki Nakamura

Takeshi Ishii

Taihei Maehara

Masatoshi Hoshino

Seiji Hijikata

Seiichi Kihara

Yuichi Ogawa

Kouji Ishikawa

Yasuharu Okazaki

Tatsuo Takishita

Kenji Yamada

Shingo Kishimoto

Junya Kawamoto

Takashi Kanai

Hajime Kurikuma

Masamichi Ito

Kenichiro Nakatani

Hiroyuki Nobezawa

Takatoshi Ooki

Hajime Yoshida

Masayuki Yunoue

Satoshi Hamamoto

Daisuke Oka

Yukiaki Nagao

Ryoya Inoue

Kenichirou Nakatani

Yuki Koto

Hiroyuki Andou

Yuuta Furukawa

Yuta Furukawa

In an electrically driven construction machine, decrease in the remaining electric power storage amount of an electric power storage device is reduced when a transition to auto idle control takes place in case where the remaining electric power storage amount is small, and the duration over which the remaining electric power storage amount of the electric power storage device lasts is lengthened. Accordingly, a controllercontrols the rotation speed of an electric motorsuch that the rotation speed of the electric motoris lowered from a predetermined rotation speed to an idle rotation speed Ni when none of a plurality of operation devices, andis manipulated and a predetermined time duration TD has elapsed. In addition, when the remaining electric power storage amount of an electric power storage deviceis equal to or smaller than a first threshold Ea, the controllersets the predetermined time duration TD shorter than when the remaining electric power storage amount is greater than the first threshold Ea.

Electrically driven construction machine driving system

In a hydraulic drive system used for an electrically driven hydraulic work machine that drives a hydraulic pump by an electric motor and supplies a hydraulic fluid to plural actuators to carry out work, the power consumption of the hydraulic pump is kept from exceeding a value decided in advance. For this purpose, a controller calculates target power to be consumed by the hydraulic pump on the basis of the capacity of the hydraulic pump, the delivery pressure of the hydraulic pump sensed by a pressure sensor, and a target revolution speed of the electric motor, and limits the target revolution speed of the electric motor in such a manner that the target power falls within a range of the maximum allowable power.

Electrically driven hydraulic work machine

An upper revolving structure () of an electric hydraulic excavator () includes a revolving frame (), an operator's seat (), an electric motor (), a hydraulic pump () driven by the electric motor (), an oil tank (), and an exterior cover () disposed in the revolving frame () to cover electrical equipment including the electric motor () and hydraulic equipment including the hydraulic pump () and the oil tank (). A partitioning member () that is disposed in the revolving frame () to partition an inside of the exterior cover () into an electrical equipment room () and a hydraulic equipment room (). An electrical equipment cooling device () including an electrical equipment cooling fan () is disposed in the electrical equipment room (), and a hydraulic equipment cooling device () including a hydraulic equipment cooling fan () is disposed in the hydraulic equipment room ().

Power-operated construction machine

It is made possible to perform power reduction control during non-operation of control levers, and suppress power consumption of a power source when a control lever is moved by an erroneous operation, and thus reduce energy consumption. Accordingly, a controllerperforms the power reduction control when a non-operation time exceeds a set time after a transition is made from a state in which at least one control lever is operated to a non-operation state in which none of the control levers is operated, and the controllercancels the power reduction control when at least one control lever is operated in a state in which the power reduction control is performed. In addition, the set time is set as a first set time Tthwhen an operation time until at least one of leversandmakes a transition to the non-operation state is longer than a monitoring time Tth, and the set time is set as a second set time Tthshorter than the first set time Tthwhen the operation time until the at least one control lever makes a transition to the non-operation state is shorter than the monitoring time Tth

Construction machine

A cable support device () for supporting an intermediate part of a power supply cable () is provided with a cable stand () attached to an upper revolving structure (), an arm member () that is rotatably attached to the cable stand () to grip the power supply cable () on the tip end side and, and a locking mechanism () that is removably disposed in the cable stand () and in the arm member () to prohibit rotation of the arm member () relative to the cable stand (). Thereby, the rotation of the arm member () relative to the cable stand () is prohibited by the locking mechanism (), making it possible to prevent the power feeding cable () retained in the arm member () from contacting a cab ().

Electric construction machine

An electrically driven construction machine is provided in which, in a case where a plurality of electrically driven construction machines operate simultaneously, it is possible to avoid exceeding the allowable electric power that can be output by the electric power receiving facility of a commercial electric power supply. A controller computes an own demanded power Pdfor driving the plurality of hydraulic actuators, on the basis of operation signals of the operation devices, computes an allowable power as a power limit value usable by the electric motor on the basis of the own demanded power, the demanded powers of the other electrically driven construction machines received through the communication device, and an allowable electric power of the electric power receiving facility of the commercial electric power supply, and controls the electric motor such that a power consumption of the electric motor does not exceed the allowable power.

Electrically driven construction machine

A controller calculates the ratio between the sum of estimated demanded powers of a plurality of first actuators and the sum of estimated demanded powers of a plurality of second actuators, and calculates, on the basis of the ratio, first and second command values for adjusting allocation between a first allowable torque of a first pump and a second allowable torque of a second pump, and first and second regulators adjust the first and second allowable torques, on the basis of first and second output pressures of first and second torque control valves, such that the first and second allowable torques become values to which a predetermined allowable torque is allocated according to the ratio described above, and control the delivery flow rates of the first and second pumps such that the respective consumed torques of the first and second pumps do not become larger than the first and second allowable torques. Thus, the present invention efficiently performs torque allocation between the first and second pumps (a plurality of hydraulic pumps) to thereby enable effective utilization of the torque generated by the prime mover without wasting the torque.

Hydraulic drive system for construction machine

To reduce an increase in the electric power consumption of an electric motor according to the state of an electric power source at the start of driving of an actuator, and make it possible to use devices in an appropriate state in an electrically driven hydraulic construction machine including a driving system that drives a hydraulic pump by using the electric motor. For this purpose, a controllersets a target relief pressure of a relief valveto a normal relief pressure Pn (first relief pressure) when an operation lever deviceis not being operated and a storage amount SOC(t) of a battery(the state quantity of an electric power source) is equal to or larger than a threshold S, and sets the target relief pressure to a reduced relief pressure Pr(t) (second relief pressure) lower than the normal relief pressure Pn (first relief pressure) when the operation lever deviceis not being operated, and the storage amount SOC(t) of the battery(the state quantity of the electric power source) is smaller than the threshold S

Electrically driven hydraulic construction machine

An electric hydraulic excavator () includes an automotive lower traveling structure () and an upper revolving structure () mounted on the lower traveling structure () to be capable of revolving thereto. The upper revolving structure () includes a revolving frame () as a base, a counterweight () disposed on a rear side of the revolving frame (), and an electric power source () that is positioned on a front side of the counterweight () to be mounted on the revolving frame () and is power-fed from an external electric current source. The counterweight () is provided with a cable insertion hole () as disposed therein. A power feeding cable () is inserted in the cable insertion hole () for connection between the external electric current source and the electric power source ().

An upper revolving structure () of a hydraulic excavator () includes a revolving frame (), a counterweight (), an operator's seat (), a right front cover (B) disposed from the right side of the operator's seat () toward a front end side of the revolving frame (), a control valve device (), and an accumulator (). An accumulator support device () is provided between the operator's seat () and the right front cover (B), the accumulator support device () is configured by a box () providing the inside thereof for an accommodating space () and having an opening () and a lid member () mounted on the box () through a hinge member () and opened and closed between an open position at which the side of a free end (D) opens the opening () and a closed position at which the side of the free end (D) closes the opening (), and the accumulator () is mounted on the lid member ().

Hydraulic excavator

A hydraulic drive system for a work machine including a hydraulic energy recovery device that is configured to perform load sensing control and accumulates hydraulic fluid that returns from a hydraulic cylinder in operation of lowering a front work implement into an accumulator includes, in order to prevent, when operation other than operation of lowering the front work implement is to be performed, hydraulic energy accumulated in the accumulator from being consumed uselessly, a regeneration selector valve in a hydraulic line for regenerating the hydraulic fluid accumulated in the accumulator into a hydraulic fluid supply line of a main pump. The regeneration selector valve is controlled such that, only when saturation occurs with the main pump, flow from the accumulator to the hydraulic fluid supply line is permitted.

Hydraulic drive system for work machine

A first torque control proportional electromagnetic valve () is connected through a first torque control line () to a third pressure receiving chamber (D) in a first torque control regulator (). A second torque control proportional electromagnetic valve () is connected through a second torque control line () to a third pressure receiving chamber (D) in a second torque control regulator (). The first and second torque control proportional electromagnetic valves () are controlled by a controller. A switching valve () is provided between the first torque control line () and the second torque control line (). The switching valve () supplies an output pressure of the first torque control proportional electromagnetic valve () to the third pressure receiving chamber (D) in the second torque control regulator () at the time of driving hydraulic motors (B,C) for left side and right side traveling.

Hydraulic drive apparatus

Even where the differential pressure across a directional control valve associated with each actuator is very small, flow dividing control of the plurality of directional control valves can be performed stable, and even where a demanded flow rate suddenly changes at the time of transition from composite action to single action or the like, a sudden change of the flow rate of hydraulic fluid to be supplied to each actuator is prevented to implement superior combined operability. Further, the meter-in loss of the directional control valves can be reduced to implement a high energy efficiency. To this end, a plurality of pressure compensating valvesandfor controlling such that the pressure in the downstream side of the meter-in opening of a plurality of directional control valvesandbecomes equal to the highest load pressure are individually arranged in the downstream side of meter-in openings of the plurality of directional control valvesand, and demanded flow rates for the directional control valvesandare calculated from input amounts of operation levers. Besides, the meter-in pressure loss of a predetermined directional control valve is calculated from the demanded flow rates for and meter-in opening areas of the directional control valvesand, and the set pressure of the unloading valveis controlled using the value of the meter-in pressure loss.

A controller () is provided with an elapse time measuring section (A) that measures an elapse time (tx) elapsed since an initial use of an accumulator () based upon a reset signal from a reset switch (), a number-of-operations measuring section (B) that measures a number of operations of the accumulator (), that is, a number (N) of boom lowering operations after a reset, based upon a detection signal from an accumulator side pressure sensor (), a gas permeation amount estimating section (C) that estimates an estimation gas permeation amount (Qloss) of the accumulator (), a sealed gas pressure estimating section (D) that finds an estimation sealed gas pressure (Pgs) of a gas chamber (B) of the accumulator (), and an accumulator degradation determining section (E) that determines a degradation condition of the accumulator () and outputs the determination result.

Hydraulic energy recovery apparatus for working machine

When a swing motor and a boom cylinder are driven simultaneously, a hydraulic drive system appropriately adjusts a distribution of torques between hydraulic pumps and feeds back a torque actually consumed by the hydraulic pump for actuating the swing motor accurately to the hydraulic pump for actuating the boom cylinder. To that end, when boom raising and swinging are performed simultaneously, the hydraulic drive system corrects an allowable torque of a hydraulic pumpthat supplies a hydraulic fluid to a swing motorso as to be lowered by a certain ratio, reducing allowable torques of hydraulic pumpsandthat supply a hydraulic fluid to a boom cylinderby torques consumed by the hydraulic pumpsandthat supply a hydraulic fluid to the swing motor

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Moriyama, Japan

Kiwamu Takahashi