Hitachi Construction Machinery Co., Ltd.

Akira Watanabe

Ken Takeuchi

Seiji Ishida

Tadashi Osaka

Yasunori Ota

Itaru Naya

Haruki Sugiyama

Yusuke Imai

Manabu Yano

Yuki Makimura

A control device of an electric hydraulic excavator sets or computes a rotation speed command and an allowable torque of an electric motor on the basis of a required rotation speed of the electric motor, and a sum of a suppliable electric power of a converter and a battery suppliable electric power. An inverter of the electric hydraulic excavator sets the allowable torque to a torque command if a calculated torque of the electric motor computed by multiplying by a gain, a difference between the rotation speed command and a rotation speed of the electric motor, exceeds the allowable torque, and sets the calculated torque to the torque command if the calculated torque does not exceed the allowable torque. The inverter supplies the electric power that can generate a torque corresponding to the torque command to the electric motor.

Electric work machine

A work machine includes: a controller; a first electrical circuit provided with a first power supply that supplies power to the controller; an electric drive source necessary for operating the work machine; and a second electrical circuit provided with a second power supply that supplies power to the electric drive source. The work machine further includes: a capacitor provided to the second electrical circuit; a first precharge device that performs precharge of the capacitor by using power of the first power supply; and a second precharge device that performs precharge of the capacitor by using power of the second power supply. The controller performs precharge by using one of the precharge devices when it is determined that precharge by using the other one of the precharge devices is impossible.

Work machine

A management server receives a maximum value and a minimum value of the respective voltages in a plurality of battery cells configuring an electricity storage device of a hydraulic excavator from the hydraulic excavator, and stores the values in a storage device. Discharge characteristics of the electricity storage device are stored in the storage device in the management server. A battery state estimation calculating unit in the management server calculates an estimation maximum value and an estimation minimum value of cell voltages in the present or in the future by adding the discharge characteristics stored in the storage device to the latest maximum value and the latest minimum value of the cell voltages stored in the storage device. A management information producing unit outputs information based upon the estimation maximum value and the estimation minimum value of the cell voltages calculated in the battery state estimation calculating unit.

Electricity storage device management computer for a construction machine

An engine cooling system () includes an engine (), an engine cooling pipe line (), an engine water pump () and an engine radiator (). An electricity storage device cooling system () includes an electricity storage device (), an electricity storage device cooling pipe line (), an electricity storage device water pump () and an electricity storage device radiator (). Different heat-transfer media (engine cooling water and electricity storage device cooling water) flow respectively in the engine cooling system () and the electricity storage device cooling system (). Further, a heating heat exchanger () is provided in the halfway of the engine cooling pipe line () and in the halfway of the electricity storage device cooling pipe line () for performing heat exchange between the engine cooling water and the electricity storage device cooling water.

Hybrid working machine

A storage battery () is configured of a plurality of cells (A) to (N) series-connected to each other. A battery controller () receives power supplied from a lead battery (). The battery controller () executes balancing control that reduces variation in cell voltages (VcA) to (VcN) of the plurality of cells (A) to (N). The battery controller () executes the balancing control in a time range during which a voltage of the lead battery () becomes equal to or more than a predetermined given voltage value (V) and a charging rate of the storage battery () becomes equal to or more than a predetermined given charging rate value (SOC) after a key switch () is switched from an on state to an off state.

Growing community of inventors

Ushiku, Japan

Akira Watanabe