Abstract: A power generation system includes a first power generation apparatus and a second power generation apparatus outputting alternating voltages by an input of vibrations; a first voltage-doubling rectifier circuit not only rectifying the alternating voltages output by the first power generation apparatus to store electricity, but also outputting enhanced voltages to the load instrument; a second rectifier circuit rectifying the alternating voltages output by the second power generation apparatus, and connected in series to the first voltage-doubling rectifier circuit, thereby outputting rectified voltages to the load instrument; a constant-current circuit connected in series to the load instrument, thereby limiting currents flowing to the load instrument to a predetermined current or less.

Abstract: A vibration power generation device including a multiple-degree-of-freedom vibration system comprising a first vibration system and a second vibration system, wherein a natural frequency of the first vibration system is different from a natural frequency of the second vibration system. A first mass member of the first vibration system has a hollow structure including a housing space inside, where the second vibration system is housed. A power generating element is mounted on a plate spring of the second vibration system. A support part projects within the housing space, and one end side of the plate spring is attached to the support part and supported within the housing space at a position inward from a peripheral wall of the first mass member. A second mass member of the second vibration system is attached to another end side of the plate spring.

Abstract: Provided is an electric construction machine adapted to prevent an electric current, after flowing in via a junction at which power transmission systems join together, from flowing into at least one connector to which an external power supply is not connected. Power transmission systems 71A, 71B, 71C connected to connectors 59A, 59B, 59C are all caused to join with a common system 73 at a junction before being connected to a control unit 35. The power transmission systems 71A, 71B, and 71C include switches 74Aa, 74Ab, 74Ba, 74Bb, 74Ca, 74Cb.

Abstract: A power generator including: a vibration system configured to be attached to a vibrating member; and a power generating element attached to the vibration system. The vibration system is a multiple-degree-of-freedom vibration system that includes a first vibration system having a first mass member elastically supported by a first spring member, and a second vibration system having a second mass member elastically connected to the first mass member by a second spring member. The power generating element is arranged between the first and second mass members, and vibration applied from the vibrating member causes relative displacement of the first and second mass members so that vibration energy of the vibrating member is input to the power generating element. A natural frequency of the first vibration system is different from that of the second vibration system.

Abstract: A vibration power generator includes a vibration system attached to a vibrating member. The vibration system includes a first vibration subsystem, and a second vibration subsystem attached to the first vibration subsystem. The first vibration subsystem includes an elastic member attached to the vibrating member, and a first mass member attached to the elastic member. The second vibration subsystem includes a plate spring integral with a piezoelectric element, and a second mass member attached to the plate spring. The first vibration subsystem has a resonant frequency that is substantially equal to a resonant frequency of the second vibration subsystem.

Abstract: A magnetostrictive vibration power generation device including: a longitudinal magnetostrictive element formed of a magnetostrictive material and configured to be attached to a vibrating member at at least one end part thereof; a coil wound on a closed magnetic path constituted including the magnetostrictive element; and a permanent magnet arranged so as to apply a bias magnetic field to the closed magnetic path. A yoke member formed of a magnetic material is arranged in parallel at a side of the magnetostrictive element, and the closed magnetic path is formed including the magnetostrictive element and the yoke member, the permanent magnet is attached to the yoke member on the closed magnetic path, and the yoke member is allowed relative displacement in relation to the magnetostrictive element on at least one side in a magnetic path lengthwise direction of the closed magnetic path.

Abstract: A power generation system includes a first power generation apparatus and a second power generation apparatus outputting alternating voltages by an input of vibrations; a first voltage-doubling rectifier circuit not only rectifying the alternating voltages output by the first power generation apparatus to store electricity, but also outputting enhanced voltages to the load instrument; a second rectifier circuit rectifying the alternating voltages output by the second power generation apparatus, and connected in series to the first voltage-doubling rectifier circuit, thereby outputting rectified voltages to the load instrument; a constant-current circuit connected in series to the load instrument, thereby limiting currents flowing to the load instrument to a predetermined current or less.

Abstract: An electric drive unit for a construction machine is capable of increasing the operating time of the construction machine. The electric drive unit has an electricity storage device, a hydraulic pump of the fixed displacement type which is driven by a motor/generator, a plurality of directional control valves which respectively control the flow of hydraulic fluid supplied to a plurality of hydraulic actuators, a bidirectional converter which performs variable control on the revolution speed of the motor/generator, and an LS control device which controls the bidirectional converter so that LS differential pressure Pls equals a target value Pgr. The bidirectional converter performs regeneration control for converting the inertial force of the rotor of the motor/generator into electric power thereby charging the electricity storage device when the revolution speed of the motor/generator is decreased in response to an excess of the LS differential pressure Pls over the target value Pgr.

Abstract: A vibration power generation device including a multiple-degree-of-freedom vibration system comprising a first vibration system and a second vibration system, wherein a natural frequency of the first vibration system is different from a natural frequency of the second vibration system. A first mass member of the first vibration system has a hollow structure including a housing space inside, where the second vibration system is housed. A power generating element is mounted on a plate spring of the second vibration system. A support part projects within the housing space, and one end side of the plate spring is attached to the support part and supported within the housing space at a position inward from a peripheral wall of the first mass member. A second mass member of the second vibration system is attached to another end side of the plate spring.

Abstract: A vibration power generator includes a vibration system attached to a vibrating member. The vibration system includes a first vibration subsystem, and a second vibration subsystem attached to the first vibration subsystem. The first vibration subsystem includes an elastic member attached to the vibrating member, and a first mass member attached to the elastic member. The second vibration subsystem includes a plate spring integral with a piezoelectric element, and a second mass member attached to the plate spring. The first vibration subsystem has a resonant frequency that is substantially equal to a resonant frequency of the second vibration subsystem.

Abstract: An electric drive unit for a construction machine is capable of increasing the operating time of the construction machine. The electric drive unit has an electricity storage device, a hydraulic pump of variable displacement type which is driven by a motor/generator, a regulator which performs variable control on the displacement volume of the hydraulic pump, a bidirectional converter which performs variable control on the revolution speed of the motor/generator, and an LS control device which controls the regulator and the bidirectional converter so that LS differential pressure Pls equals a target value Pgr. The bidirectional converter performs regeneration control for converting the inertial force of the rotor of the motor/generator into electric power thereby charging the electricity storage device when the revolution speed of the motor/generator is decreased in response to an excess of the LS differential pressure Pls over the target value Pgr.

Abstract: A power generator including: a vibration system configured to be attached to a vibrating member; and a power generating element attached to the vibration system. The vibration system is a multiple-degree-of-freedom vibration system that includes a first vibration system having a first mass member elastically supported by a first spring member, and a second vibration system having a second mass member elastically connected to the first mass member by a second spring member. The power generating element is arranged between the first and second mass members, and vibration applied from the vibrating member causes relative displacement of the first and second mass members so that vibration energy of the vibrating member is input to the power generating element. A natural frequency of the first vibration system is different from that of the second vibration system.

Abstract: A magnetostrictive vibration power generation device including: a longitudinal magnetostrictive element formed of a magnetostrictive material and configured to be attached to a vibrating member at at least one end part thereof; a coil wound on a closed magnetic path constituted including the magnetostrictive element; and a permanent magnet arranged so as to apply a bias magnetic field to the closed magnetic path. A yoke member formed of a magnetic material is arranged in parallel at a side of the magnetostrictive element, and the closed magnetic path is formed including the magnetostrictive element and the yoke member, the permanent magnet is attached to the yoke member on the closed magnetic path, and the yoke member is allowed relative displacement in relation to the magnetostrictive element on at least one side in a magnetic path lengthwise direction of the closed magnetic path.

Abstract: Provided is an electric construction machine adapted to prevent an electric current, after flowing in via a junction at which power transmission systems join together, from flowing into at least one connector to which an external power supply is not connected. Power transmission systems 71A, 71B, 71C connected to connectors 59A, 59B, 59C are all caused to join with a common system 73 at a junction before being connected to a control unit 35. The power transmission systems 71A, 71B, and 71C include switches 74Aa, 74Ab, 74Ba, 74Bb, 74Ca, 74Cb.

Abstract: A control pressure switching valve is disposed between a displacement regulator and a pressure control valve. The control pressure switching valve is switched between a control position (j), in which a load sensing control pressure (PLS) is permitted to be outputted from the pressure control valve to the displacement regulator, and a control release position (k), in which the load sensing control pressure (PLS) to be outputted to the displacement regulator is reduced to a prescribed low pressure value. When the regeneration of a filter is determined to be necessary, the controller switches the control pressure switching valve to the control release position (k). When the load sensing control pressure (PLS) is reduced to the low pressure value with the control pressure switching valve switched to the control release position (k), the displacement regulator increases a delivery displacement of a hydraulic pump, thereby increasing rotational load of an engine.

Abstract: An electromotive drive device of an electric motor-driven mini-excavator, which is capable of lengthening its operating time, includes an electric power storage device, a motor-generator, a hydraulic pump, a plurality of directional control valves which respectively control the flow of pressurized fluid, and a plurality of operating devices which respectively operate the plurality of directional control valves. The electromotive drive device is provided with a bidirectional converter which decelerates the motor-generator to an idle revolution speed when X seconds have elapsed in a state in which the plurality of directional control valves are all not operated. The bidirectional converter performs regenerative control to convert an inertial force of a rotor of the motor-generator to power and charge the electric power storage device when it decelerates the motor-generator from a standard revolution speed to the idle revolution speed.

Abstract: A control pressure switching valve is disposed between a displacement regulator and a pressure control valve. The control pressure switching valve is switched between a control position (j), in which a load sensing control pressure (PLS) is permitted to be outputted from the pressure control valve to the displacement regulator, and a control release position (k), in which the load sensing control pressure (PLS) to be outputted to the displacement regulator is reduced to a prescribed low pressure value. When the regeneration of a filter is determined to be necessary, the controller switches the control pressure switching valve to the control release position (k). When the load sensing control pressure (PLS) is reduced to the low pressure value with the control pressure switching valve switched to the control release position (k), the displacement regulator increases a delivery displacement of a hydraulic pump, thereby increasing rotational load of an engine.

Abstract: An electric construction machine is capable of increasing a battery device charging rate in a short charging time. The battery device includes a plurality of battery systems and an inverter device which has a motor driving control function of selectively connecting one of the battery systems, converting DC power supplied from the connected battery system into AC power, and supplying the AC power to an electric motor. The inverter has a battery charging control function of selectively connecting one of the battery systems and supplying electric power from an external commercial power supply to the connected battery system. When the voltages of the battery systems are less than an upper limit value V1 at the start of the charging, constant-current charging of one battery system is started. Before the one battery system reaches the fully charged state, the connection is switched to another battery system to start constant-current charging thereof.

Abstract: An electrically-operated construction machine with a battery charging operation. A lock switch provides a closed contact when a lock lever in a cab is placed in an unlock position. A feed port is disposed outside the cab to accept a cable from a commercial power source. The feed port is provided with a charge start switch. A control device has a motor control function for driving an electric motor with electrical power of a main battery when a signal is input from the lock switch. A charge control function is for charging the main battery with electrical power of the commercial power source when dictated by the charge start switch. The lock switch is wire-connected so as not to output the signal to the control device even if the closed contact is provided by the lock switch when the control device exercises charge control.

Abstract: A construction machine that can limit consumption of battery electric power is provided. The construction machine includes: air-cooled heat exchangers 47, 48; a cooling fan 49 for generating cooling air for the heat exchangers 47, 48; a fan electric drive motor 50 that is driven by electric power of a battery 8 for rotating the cooling fan 49; an inverter unit 30 for drivingly controlling the fan electric drive motor 50; a lock lever 25 disposed at a boarding-alighting port and configured to be operated into an unlocked position and a locked position; and a lock valve 42 for making an operation of an operating device 27 or the like ineffective or the operating device inoperative when the lock lever 25 is operated into the locked position. The inverter unit 30 stops the fan electric drive motor 50 when the lock lever 25 is operated into the locked position.