JP5390436B2 - Electric construction machine - Google Patents

Description

  The present invention relates to an electric construction machine using a battery-driven electric motor as a power source.

  For example, as an electric construction machine such as a hydraulic excavator, an electric motor is driven using a main battery mounted on a vehicle, a hydraulic pump is operated using the electric motor as a drive source, and the hydraulic pressure generated by the hydraulic pump is generated. A device that uses a hydraulic cylinder of a working device or a traveling hydraulic motor is known (for example, see Patent Document 1).

  Also, as an engine-driven construction machine, one that increases the running speed by minimizing the capacity of the hydraulic motor while maximizing the engine speed and the capacity of the hydraulic pump by performing a switch operation in an emergency. It is known (see, for example, Patent Document 2).

  Further, as an engine-driven construction machine, a configuration is also known in which when only a work device is operated, the output of the engine is kept low, and the output restriction is released when the vehicle is running to run at high speed (for example, a patent Reference 3).

JP 2007-32462 A JP 2006-97855 A JP-A-1-294920

  By the way, in an electric construction machine, for example, during excavation work using a working device, it is better to reduce the rotation speed of the electric motor in order to suppress the power consumption of the main battery. On the other hand, when the vehicle is traveling at a high speed, it is necessary to increase the amount of pressure oil supplied from the hydraulic pump by increasing the rotational speed of the electric motor.

  In contrast, Patent Documents 2 and 3 disclose configurations in which the traveling speed of the vehicle can be increased. However, in these construction machines, in order to increase the traveling speed of the vehicle, it is necessary to adjust the engine output by operating special switching means such as an emergency switch and a lock lever, thereby increasing the traveling speed of the vehicle. For this reason, there is a problem that the operation is complicated and the workability is lowered.

  The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to provide an electric construction machine that can increase the traveling speed of a vehicle by a simple operation.

  In order to solve the above-described problem, an electric construction machine according to the invention of claim 1 is provided with a self-propelled vehicle body provided with a driver's seat, a main battery provided on the vehicle body, and the main battery. Boosting circuit for boosting DC voltage, inverter for converting DC power supplied from the boosting circuit to AC power, electric motor driven by AC power supplied from the inverter, and hydraulic pressure driven by the electric motor A pump, a variable displacement traveling hydraulic motor that is driven using hydraulic pressure from the hydraulic pump and that causes the vehicle body to travel at a high speed or a low speed in accordance with a capacity switching by a capacity switching valve; A traveling operation device for controlling the traveling hydraulic motor in accordance with the traveling operation of the vehicle, and switching the capacity switching valve of the traveling hydraulic motor to switch the vehicle A travel mode switch for selecting either high speed or low speed as the travel speed of the motor, a rotation speed setting device for setting the rotation speed of the electric motor, an energy saving mode switch for suppressing power consumption of the main battery, A drive mode switch and a rotation speed control device for controlling the inverter according to the energy saving mode switch and controlling the rotation speed of the electric motor, wherein the rotation speed control device switches the energy saving mode switch to the energy saving mode. The energy-saving mode driving device for driving the electric motor at the set rotational speed set by the rotational speed setter regardless of the traveling operation of the traveling operation device, and the energy-saving mode switch is switched to the non-energy-saving mode. In the case where the high speed side is selected by the travel mode switch, the travel operation device Non-energy-saving mode drive device that drives the electric motor at a set rotational speed set by the rotational speed setter when in the neutral position and increases the rotational speed of the electric motor when the travel operation device is traveled It is set as the structure provided with.

  According to a second aspect of the present invention, a power mode switch is provided that enables the electric motor to be driven at a maximum number of revolutions when the travel operation device is in a neutral position, and the revolution number setting device is configured to switch the power mode switch to a power mode. When the power mode switch is switched to the non-power mode, the set rotational speed can be set within a range equal to or less than the maximum rotational speed of the electric motor. It can be set in a range of a predetermined rotation speed that is lower than the maximum rotation speed.

  In the invention of claim 3, when the power mode switch is switched to the non-power mode, the operation amount of the travel operation device exceeds a predetermined first threshold value. A normal mode processing device that sometimes increases the rotational speed of the electric motor, and a second operation amount of the travel operation device smaller than the first threshold value when the power mode switch is switched to the power mode. And a power mode processing device that increases the rotational speed of the electric motor when the threshold value is exceeded.

  According to a fourth aspect of the invention, the travel mode switch, the energy saving mode switch, the power mode switch, and the rotation speed setting device are attached to a console disposed in the vicinity of the driver seat.

  According to a fifth aspect of the present invention, a battery controller that detects an abnormality of the main battery is provided, and the non-energy-saving mode drive device performs a traveling operation of the traveling operation device when the abnormality of the main battery is detected by the battery controller. Regardless, the battery abnormality processing device is configured to drive the electric motor at the set rotational speed set by the rotational speed setter.

  As described above, according to the first aspect of the present invention, when the energy saving mode switch is switched to the energy saving mode, the energy saving mode drive device performs the traveling operation of the traveling operation device including the traveling lever, the traveling pedal, and the like. The electric motor is driven at the set rotational speed set by the rotational speed setter regardless of the above. For this reason, when excavation work or the like is performed with the vehicle stopped, the power consumption of the main battery can be reliably suppressed by setting the set rotational speed to a low speed, and the operating time of the construction machine is lengthened. be able to.

  On the other hand, the non-energy-saving mode drive device, when the energy-saving mode switch is switched to the non-energy-saving mode, uses the rotation speed setting device when the traveling operation device is in the neutral position with the high-speed side selected by the traveling mode switch. The electric motor is driven at the set rotational speed that is set, and the rotational speed of the electric motor is increased when the travel operation device is traveled. As a result, when the vehicle is driven, if the operator sets the travel mode switch to the high speed side in advance, the rotational speed of the electric motor can be automatically increased only by performing the travel operation of the travel operation device. . Further, when the traveling operation device is returned to the neutral position, the rotational speed of the electric motor can be reduced to the set rotational speed. For this reason, for example, even when the vehicle is traveling at a high speed, there is no need for a special operation for increasing the rotation speed of the electric motor, and it is only necessary to travel the traveling operation device, thus simplifying the operation and improving workability. be able to.

  According to the invention of claim 2, when the power mode switch is switched to the power mode, the rotational speed setter can set the rotational speed within a range equal to or less than the maximum rotational speed of the electric motor. For this reason, for example, when performing excavation work under heavy load, if the operator switches the power mode switch to the power mode, even if the traveling operation device is in the neutral position, it is set by the operator within the range of the maximum rotation speed or less. The electric motor can be driven at the set rotational speed at a high speed.

  In addition, when the power mode switch is switched to the non-power mode, the rotational speed setter can set the rotational speed within a range below a predetermined rotational speed that is lower than the maximum rotational speed of the electric motor. For example, when a normal excavation operation with a light load is performed, a value lower than the maximum number of rotations of the electric motor is sufficient. For this reason, when the load is light, the set rotational speed is set to a value that is lower than the predetermined rotational speed, which is lower than the maximum rotational speed. Therefore, it is possible to reduce the rotational speed of the electric motor to suppress the power consumption of the main battery. it can.

  According to the third aspect of the present invention, the normal mode processing device of the non-energy saving mode driving device operates in the normal mode in which the power mode switch is switched to the non-power mode in the state of switching to the non-energy saving mode. Is configured to increase the rotation speed of the electric motor when the value exceeds a predetermined first threshold value. For this reason, in the normal mode, when the operation amount of the travel operation device is smaller than the first threshold value, the rotation speed of the electric motor is maintained at the set rotation speed. At this time, the hydraulic pump driven by the electric motor can supply the traveling motor with pressure oil corresponding to the low-speed traveling of the vehicle. Further, when the operation amount of the travel operation device is larger than the first threshold value, the rotational speed of the electric motor is increased. Thereby, the hydraulic pump driven by the electric motor can supply pressure oil according to the high-speed traveling of the vehicle to the traveling motor.

  On the other hand, the power mode processing device of the non-energy-saving mode drive device operated the traveling operation device exceeding the second threshold when the power mode switch was switched to the power mode in the state of switching to the non-energy-saving mode. In some cases, the rotational speed of the electric motor is increased. For this reason, in the power mode, when the operation amount of the travel operation device is smaller than the second threshold value, the rotation speed of the electric motor is maintained at the set rotation speed. Further, when the operation amount of the travel operation device is larger than the second threshold value, the rotational speed of the electric motor is increased. Thereby, the hydraulic pump driven by the electric motor can supply pressure oil corresponding to the traveling speed of the vehicle to the traveling motor, as in the normal mode.

  Further, the second threshold value is smaller than the first threshold value. For this reason, in the power mode, the rotational speed of the electric motor is increased with a smaller operation amount than in the normal mode, so that the vehicle can be driven at high speed quickly.

  According to the invention of claim 4, the traveling mode switch, the energy saving mode switch, the power mode switch, and the rotation speed setting device are configured to be attached to a console disposed in the vicinity of the driver's seat. For this reason, the operator can operate the travel mode switch, the energy saving mode switch, the power mode switch, and the rotation speed setting device while sitting in the driver's seat, and can quickly switch between the energy saving mode, the normal mode, and the power mode. Can do.

  According to the invention of claim 5, when the battery controller detects the abnormality of the main battery by the battery controller, the battery abnormality processing device of the non-energy-saving mode drive device is set by the rotation speed setting device regardless of the traveling operation of the traveling operation device. The electric motor is driven at the set rotational speed. For this reason, in a situation where it is inappropriate to drive the electric motor at high speed rotation, for example, due to insufficient charging of the main battery, the rotation speed of the electric motor can be maintained at the set rotation speed.

1 is a front view showing a hydraulic excavator according to an embodiment of the present invention. It is a top view which shows the hydraulic shovel in FIG. It is sectional drawing which looked around the driver's seat from the arrow III-III direction in FIG. It is a top view which expands and shows the switch box in FIG. It is a block diagram which shows the structure of the power supply system etc. which are applied to the hydraulic shovel in FIG. It is a circuit diagram which shows the structure of the control panel in FIG. It is a flowchart which shows the rotation speed control process of the electric motor by the system controller in FIG. In a normal mode, it is a characteristic diagram which shows the relationship between the operation amount of a travel lever pedal apparatus, and the rotation speed of an electric motor. In a power mode, it is a characteristic diagram which shows the relationship between the operation amount of a travel lever pedal apparatus, and the rotation speed of an electric motor. It is a characteristic diagram which shows the time change of the rotation speed of the electric motor when operating a travel lever pedal apparatus in an energy saving mode. It is a characteristic diagram which shows the time change of the rotation speed of an electric motor when a driving | running | working lever pedal apparatus is operated in normal mode. It is a characteristic diagram which shows the time change of the rotation speed of an electric motor when operating a travel lever pedal apparatus in a power mode.

  Hereinafter, a case where the present invention is applied to a small hydraulic excavator as an electric construction machine according to an embodiment of the present invention will be described as an example and described in detail with reference to the accompanying drawings.

  In the figure, reference numeral 1 denotes a canopy-type hydraulic excavator as an electric construction machine. The hydraulic excavator 1 includes a crawler-type lower traveling body 2 capable of self-propelling and the lower traveling as shown in FIGS. 1 and 2. The upper revolving body 3 that is mounted on the body 2 so as to be able to swivel and constitutes the vehicle body of the excavator 1 together with the lower traveling body 2 and a work device 5 described later are roughly constituted. In this small hydraulic excavator 1, the radius (rear end turning radius) between the turning center and the rear end of the upper turning body 3 is set to a value of 1.5 m or less (preferably 1.3 m or less), for example. .

  The lower traveling body 2 includes left and right crawler belts 2A, and the crawler belts 2A are wound between idle wheels 2B and drive wheels 2C. Further, the lower traveling body 2 is provided with a traveling motor 36 described later in order to rotationally drive the drive wheels 2C.

  Reference numeral 4 denotes a revolving frame constituting a support structure for the upper revolving structure 3. The revolving frame 4 is provided on the lower traveling body 2 so as to be revolved, and is revolved by a revolving motor (not shown) comprising a hydraulic motor. . A work device 5 (front device) is attached to the front portion of the revolving frame 4 so as to be able to move up and down.

  The working device 5 includes a boom 6, an arm 7, and a bucket 8, and hydraulic cylinders such as a boom cylinder 9, an arm cylinder 10, and a bucket cylinder 11 are attached to the boom 6, arm 7, and bucket 8. And these cylinders 9-11 comprise the actuator driven with the hydraulic pressure supplied from the below-mentioned hydraulic pump 33 with the traveling motor 36, the turning motor, etc.

  A driver's seat 12 is provided on the upper swing body 3, and the driver's seat 12 is disposed on the left side of the front portion of the swing frame 4, for example, and is seated by an operator. The upper side of the driver seat 12 is covered with a canopy 13. Further, consoles 15 and 16, which will be described later, are provided on both the left and right sides of the driver's seat 12, and a traveling lever / pedal device 29, which will be described later, is provided on the floor 14 in front of the driver's seat 12. .

  15 is a left console provided on the left side of the driver's seat 12 near the entrance and exit, and the left console 15 has a console box 15A as shown in FIG. 3, on the front side of the console box 15A, The left operating lever 15B is provided in a state where tilting operation is possible.

  Reference numeral 16 denotes a right console provided on the right side of the driver's seat 12 in the vicinity of the driver's seat 12, and the right console 16 is disposed at a position farther from the driver's seat 12 when viewed from the entrance / exit. The right console 16 includes a console box 16A, an operation lever 16B, and the like, like the left console 15. The right operation lever 16B is for operating the work device 5 and the like, for example, when the operator performs a tilting operation together with the left operation lever 15B.

  Reference numeral 17 denotes a switch box provided on the right console 16. On the upper surface of the switch box 17, a light switch 18, a travel mode switch 19, an energy saving mode switch 20, and a power mode switch 21 are provided as shown in FIG. In addition, a rotation speed setting dial 22 as a rotation speed setting device is provided.

  Here, the light switch 18 is a switch for turning on or off an illumination lamp (not shown) such as a headlamp. The traveling mode switch 19 selectively switches the traveling speed of the vehicle between a high speed side and a low speed side, and includes a high speed selection unit 19A and a low speed selection unit 19B. The travel mode switch 19 has a function of switching the capacity variable section 36A of the travel motor 36 to either a small capacity or a large capacity as will be described later according to the selection sections 19A and 19B.

  Specifically, when the high speed selection unit 19A is selected, the travel mode switch 19 is turned on, and the capacity variable unit 36A of the travel motor 36 is switched to a small capacity. On the other hand, when the low speed selection unit 19B is selected, the travel mode switch 19 is turned off, and the capacity variable unit 36A of the travel motor 36 is switched to a large capacity.

  The energy saving mode switch 20 is provided to suppress power consumption of the main battery 40. For this reason, in the energy saving mode in which the energy saving mode switch 20 is turned on, the electric motor 39 is driven to rotate at the set rotation speed Ns set by the rotation speed setting dial 22. On the other hand, in the non-energy saving mode in which the energy saving mode switch 20 is turned off, the mode is switched to a normal mode or a power mode, which will be described later, according to the on / off state of the power mode switch 21.

  The power mode switch 21 is provided, for example, to keep the rotational speed N of the electric motor 39 at a high speed when performing excavation work or the like under heavy load. More specifically, in the non-power mode (power saving mode, normal mode) in which the power mode switch 21 is turned off, the setting range of the set rotation speed Ns by the rotation speed setting dial 22 is greater than the maximum rotation speed Nmax of the electric motor 39. Is also limited to a range below a predetermined rotation speed N0 (for example, N0 = 1800 rpm).

  On the other hand, in the power mode in which the power mode switch 21 is turned on, the setting range of the set rotational speed Ns by the rotational speed setting dial 22 is extended to the maximum rotational speed Nmax (for example, Nmax = 2400 rpm) of the electric motor 39. Thus, when the power mode switch 21 is turned on, the electric motor 39 can be driven to rotate at the maximum rotational speed Nmax even when a travel lever / pedal device 29 described later is in the neutral position.

  The power mode switch 21 is not turned on together with the energy saving mode switch 20, and when one of them is on, the other is turned off. Moreover, both the energy saving mode switch 20 and the power mode switch 21 can be turned off together. Accordingly, any one of the energy saving mode in which the energy saving mode switch 20 is turned on, the power mode in which the power mode switch 21 is turned on, and the normal mode in which both of these two switches 20 and 21 are turned off is selected. One operation mode is selected.

  The rotation speed setting dial 22 sets the rotation speed N of the electric motor 39 and determines the set rotation speed Ns according to the rotation position. The setting range of the set rotational speed Ns varies depending on whether the power mode switch 21 is on or off. Specifically, in the power mode in which the power mode switch 21 is turned on, the set rotational speed Ns can be set within a range of the maximum rotational speed Nmax of the electric motor 39. In the present embodiment, the set rotational speed Ns can be set, for example, in a range between a predetermined minimum rotational speed Nmin (for example, Nmin = 1300 rpm) and a maximum rotational speed Nmax.

  On the other hand, in the energy saving mode and the normal mode in which the power mode switch 21 is turned off, the set rotational speed Ns can be set in a range of a predetermined rotational speed N0 or less, which is lower than the maximum rotational speed Nmax of the electric motor 39. . Specifically, the set rotational speed Ns can be set within a range between the minimum rotational speed Nmin and the predetermined rotational speed N0, for example, as a range below the predetermined rotational speed N0 that is 75% of the maximum rotational speed Nmax. Thereby, in the power mode, the set rotational speed Ns can be increased compared to the energy saving mode and the normal mode.

  The rotation speed setting device is not limited to the dial type in which the set rotation speed Ns is determined according to the rotation position, such as the rotation speed setting dial 22, but may be of other types such as a slide type and a lever type.

  Further, on the upper surface of the switch box 17, an integrated time display panel 23 indicating the integrated operation time of the excavator 1 and a voltage display panel 24 indicating the voltage of the main battery 40 described later are provided. Further, on the upper surface of the switch box 17, a drivable lamp 25 indicating that the excavator 1 is drivable, a drivable lamp 26 indicating that the excavator 1 is drivable, and a main battery 40 are displayed. A normal voltage lamp 27 indicating that the voltage is normal, an abnormal voltage lamp 28 indicating that the voltage of the main battery 40 is lowered, and the like are provided.

  Reference numeral 29 denotes a travel lever / pedal device as a travel operation device provided on the floor plate 14 located on the front side of the driver's seat 12, and the travel lever / pedal device 29 is provided on the left and right sides as shown in FIG. A travel lever 30A, 30B and left and right travel pedals 31A, 31B are provided. Then, the operator seated in the driver's seat 12 manually tilts the travel levers 30A and 30B or depresses the travel pedals 31A and 31B as the travel operation of the travel lever / pedal device 29. Thus, the traveling speed of the vehicle is increased or decreased according to the operation amount θ.

  In this case, the operation amount θ of the travel levers 30A, 30B or the travel pedals 31A, 31B is detected by the operation amount sensor 32 (only one is shown in FIG. 5), and the detected signal is a system controller 51 described later. Is output toward. Then, the system controller 51 controls a control valve device 34 described later in accordance with a detection signal from the operation amount sensor 32.

  Further, the left and right traveling levers 30A and 30B are steered (steered), for example, when the operator appropriately varies the operation amount θ. This is the same when the left and right traveling pedals 31A and 31B are depressed at different angles.

  Reference numeral 33 denotes a hydraulic pump as a hydraulic source. The hydraulic pump 33 is provided on the right side of the driver's seat 12 in the upper swing body 3, for example. Then, as shown in FIGS. 2 and 5, the hydraulic pump 33 is rotationally driven by an electric motor 39 described later to generate hydraulic pressure. The hydraulic pump 33 is connected to each of the cylinders 9 to 11 and a travel motor 36 described later via a control valve device (C / V) 34 including a plurality of directional control valves. The hydraulic pump 33 sucks the hydraulic oil in the oil tank 35 to generate high pressure oil pressure, and supplies this oil pressure to each of the cylinders 9 to 11 and the travel motor 36.

  At this time, when the operator seated on the driver's seat 12 shown in FIG. 3 operates the operation levers 15B and 16B, the control valve device 34 is switched. Thereby, for example, supply and discharge of hydraulic pressure to each cylinder 9 to 11 are switched, and the expansion and contraction operation of each cylinder 9 to 11 is controlled using the control valve device 34. Further, when the operator operates the travel levers 30A, 30B or the travel pedals 31A, 31B, the control valve device 34 is switched. As a result, the supply and discharge of the traveling motor 36 are switched, and the flow rate of the pressure oil to the traveling motor 36 is increased or decreased according to the operation amount of the traveling lever / pedal device 29. As a result, the rotation direction and rotation speed of the traveling motor 36 are controlled.

  Reference numeral 36 denotes a traveling motor (only one is shown in FIG. 5) as left and right traveling hydraulic motors provided in the lower traveling body 2, and the traveling motor 36 has a variable displacement type having a capacity variable portion 36A. It is constituted by a hydraulic motor and is connected to a hydraulic pump 33 via a control valve device 34. The traveling motor 36 is driven to rotate by supplying and discharging the pressure oil from the hydraulic pump 33, and the rotation speed changes according to the flow rate of the pressure oil. Depending on the rotational speed of the traveling motor 36, the traveling speed of the vehicle is increased or decreased.

  Reference numeral 37 denotes a tilting actuator as a capacity variable mechanism attached to the traveling motor 36. The tilting actuator 37 is, for example, a traveling speed switching electromagnetic valve 38 in which pressure oil from a pilot pump (not shown) serves as a capacity switching valve. To change the displacement variable portion 36A of the travel motor 36 between the small displacement position and the large displacement position. More specifically, when the high speed selection unit 19A of the travel mode switch 19 is selected (when the travel mode switch 19 is on), the tilting actuator 37 switches the capacity variable unit 36A to the small capacity position. At this time, the traveling motor 36 is rotated at high speed with a small torque. On the other hand, when the low speed selection unit 19B of the travel mode switch 19 is selected (when the travel mode switch 19 is off), the tilting actuator 37 switches the capacity variable unit 36A to the large capacity position. At this time, the traveling motor 36 is rotated at a low speed with a large torque.

  An electric motor 39 is located near the hydraulic pump 33 and provided on the right side of the front part of the upper swing body 3. The electric motor 39 is constituted by, for example, a three-phase induction motor. The output shaft of the electric motor 39 is connected to the hydraulic pump 33 and functions as a drive source of the hydraulic pump 33. The electric motor 39 is rotationally driven by three-phase AC power supplied from an inverter 42 described later, and drives the hydraulic pump 33 through its output shaft.

Reference numeral 40 denotes a main battery provided on the rear side of the upper swing body 3, and the main battery 40 is constituted by a secondary battery such as a lithium ion battery that obtains a DC voltage of a rated output of 160 V _DC , for example. As shown in FIG. 6, the main battery 40 is configured by connecting a plurality of battery cells 40A in series, and each battery cell 40A is provided with a cell controller 40B for monitoring charge / discharge. Yes. The cell controller 40B detects, for example, overcharge, overdischarge, etc., stops charging / discharging of the battery cell 40A, and outputs a detection signal at this time to a battery controller 49 described later.

  Further, since the main battery 40 itself is a heavy object, it also functions as a counterweight for the heavy load applied to the work device 5. The main battery 40 is connected to an electric motor 39 via an inverter 42 of a control panel 41 described later.

Reference numeral 41 denotes a control panel for controlling the driving of the electric motor 39 and the like. The control panel 41 is attached to, for example, an upper position of the electric motor 39 and can be connected to an external power supply via an external power supply connector (not shown). It has become. At this time, the external power source may be an external commercial power source to which a three-phase 200V _AC or single-phase 100V _AC AC voltage is supplied, or an external battery to which a 150V _DC DC voltage is supplied. The control panel 41 includes an inverter 42, an AC / DC converter 43, a step-up / step-down chopper 46, an auxiliary power circuit 47, a battery control unit 48, a system controller 51, and the like, which will be described later.

Reference numeral 42 denotes an inverter connected to the electric motor 39. The inverter 42 includes a plurality of switching elements (not shown) including transistors, thyristors, insulated gate bipolar transistors (IGBT), and the like. Here, the inverter 42 generates three-phase AC power of 200 V _AC from DC power of 288 V _DC , for example, by controlling on / off of the switching element. The inverter 42 supplies three-phase AC power to the electric motor 39 and drives the electric motor 39.

43 is an AC / DC converter (AC / DC) electrically connected between the external power source and the inverter 42, and the AC / DC converter 43, as shown in FIG. A rectifier 44 that rectifies the wave and a smoothing circuit 45 that is connected to the subsequent stage of the rectifier 44 and smoothes the power waveform. The AC / DC converter 43 converts, for example, 200 V _AC three-phase AC power supplied from an external power source into 288 V _DC DC power, and supplies it to the inverter 42. The AC / DC converter 43 can also be connected to a single-phase 100 V _AC AC power or a 150 V _DC external battery.

  A step-up / step-down chopper 46 is electrically connected between the main battery 40 and the inverter 42. The step-up / step-down chopper 46 is connected to the output side of the main battery 40 and the inverter 42 as shown in FIGS. It is electrically connected to the input side and electrically connected to the output side of the AC / DC converter 43. The step-up / step-down chopper 46 includes a plurality of switching elements made of, for example, an IGBT, a reactor made of a coil or the like, and a capacitor made of an electric field capacitor or the like.

The switching element of the step-up / down chopper 46 is controlled to be turned on / off by a system controller 51 described later. Thus, when driving the electric motor 39 using the main battery 40, the step-up / step-down chopper 46 boosts the DC voltage of, for example, 160V _DC output from the main battery 40 to the DC voltage of 288V _DC and supplies it to the inverter 42. Functions as a booster circuit (boost chopper). Further, when charging the main battery 40 using the external power source (e.g., a commercial power supply, etc.), buck-boost chopper 46, a DC voltage of output from the AC-DC converter 43 for example 288 V _DC to a DC voltage of 160 V _DC It functions as a step-down circuit (step-down chopper) that steps down and supplies it to the main battery 40.

  47 is an auxiliary power supply circuit for supplying drive voltage to a battery controller 49 and a system controller 51 described later. The auxiliary power supply circuit 47 is electrically connected to the output side of the AC / DC converter 43 and the input side of the inverter 42. And is also electrically connected to the step-up / step-down chopper 46. The auxiliary power circuit 47 includes, for example, a bridge circuit composed of a plurality of switch elements made of IGBT or the like, a transformer connected to the bridge circuit, and a rectifier connected to the secondary side (low voltage side) of the transformer. And a smoothing circuit connected to the output side of the rectifier.

The auxiliary power supply circuit 47 is controlled to be turned on / off by a system controller 51 described later. As a result, the auxiliary power supply circuit 47 steps down the DC voltage of, for example, 288 V _DC output from the AC / DC converter 43 or the step-up / step-down chopper 46 to a DC voltage of 13.5 V _DC to the battery controller 49 and the system controller 51. Functions as a step-down circuit to supply.

  The auxiliary power supply circuit 47 is connected to the system controller 51 via the travel mode switch 19, the energy saving mode switch 20, and the power mode switch 21, respectively. Therefore, the system controller 51 determines whether the switches 19 to 21 are turned on / off based on the presence / absence of a voltage signal from the auxiliary power supply circuit 47.

  Further, the auxiliary power circuit 47 is connected to the travel speed switching electromagnetic valve 38 via the travel mode switch 19. For this reason, when the high speed selector 19A is selected and the travel mode switch 19 is turned on, the drive voltage is supplied from the auxiliary power circuit 47 to the travel speed switching electromagnetic valve 38. Thereby, the traveling speed switching electromagnetic valve 38 switches the supply and discharge of the pressure oil to the tilting actuator 37 so that the capacity variable portion 36A is set to the small capacity position.

  The auxiliary power circuit 47 also functions as a driving power source for other low voltage devices such as an illumination lamp. Further, a backup low voltage (for example, 12V) auxiliary battery is connected to the output side of the auxiliary power circuit 47, and a drive voltage is supplied to the battery controller 49, the system controller 51, and the like via the auxiliary battery. Also good.

  A battery control unit 48 is provided between the main battery 40 and the step-up / step-down chopper 46. The battery control unit 48 detects the abnormality of the main battery 40, and is turned on / off by the battery controller 49. And a relay 50 that can be switched. The battery controller 49 receives a detection signal from the cell controller 40B in order to monitor the voltage of the main battery 40 and the like. Since the cell controller 40B outputs a detection signal corresponding to the content of the abnormality when an abnormality occurs in the temperature, voltage, and current of the battery cell 40A, the battery controller 49 uses this detection signal, for example, An abnormality of the main battery 40 such as a voltage drop is determined, and a signal indicating the abnormality content is output to a system controller 51 described later.

  Further, when the excavator 1 is started, the battery controller 49 determines whether or not the main battery 40 is normal using a detection signal from the cell controller 40B, and turns on the relay 50 when determining that the main battery 40 is normal. To do. On the other hand, when an abnormality occurs in the main battery 40 when the hydraulic excavator 1 is started, the battery controller 49 turns off the relay 50 and disconnects the main battery 40 from the step-up / down chopper 46.

  Reference numeral 51 denotes a system controller as a rotation speed control device configured by a microcomputer, for example, and the system controller 51 is driven by a DC voltage supplied from the auxiliary power circuit 47. The input side of the system controller 51 is connected to the travel mode switch 19, the energy saving mode switch 20, the power mode switch 21, the rotation speed setting dial 22, the operation amount sensor 32, the battery controller 49, and the like. The output side of the system controller 51 is connected to the inverter 42, the step-up / step-down chopper 46, the auxiliary power supply circuit 47, and the like.

  The system controller 51 has a storage unit 51A composed of a ROM, a RAM, and the like, and a processing program shown in FIG. 7 to be described later is stored in the storage unit 51A. Then, the system controller 51 is driven according to the processing program shown in FIG. 7, controls the inverter 42 according to on / off of the travel mode switch 19, the energy saving mode switch 20, and the power mode switch 21, and the rotational speed of the electric motor 39. N is controlled.

  The hydraulic excavator 1 according to the present embodiment has the above-described configuration, and the operation thereof will be described next.

  First, when an operator seated in the driver's seat 12 activates the electric motor 39 using, for example, an ignition key (not shown), the hydraulic pump 33 is rotationally driven by the electric motor 39. When the operator operates the traveling lever / pedal device 29 in this state, the direction control valve of the control valve device 34 is switched from the neutral position with a stroke corresponding to the operation amount θ at this time. For this reason, since the travel oil 36 on the lower travel body 2 side is supplied from the hydraulic pump 33 with a flow rate of pressure oil corresponding to the stroke of the directional control valve, the travel motor 36 rotates according to the flow rate of the pressure oil. Speed increases or decreases. As a result, the vehicle travels on the road at a travel speed substantially proportional to the rotational speed of the travel motor 36.

  When the travel mode switch 19 is turned on, the capacity variable portion 36A of the travel motor 36 is switched to the small capacity position, and the travel motor 36 is rotated at a high speed with a small torque. On the other hand, when the travel mode switch 19 is turned off, the capacity variable portion 36A of the travel motor 36 is switched to the large capacity position, and the travel motor 36 is rotated at a low speed with a large torque. The system controller 51 changes the rotational speed N of the electric motor 39 in order to increase or decrease the flow rate of the pressure oil from the hydraulic pump 33 in accordance with such a change in the rotational speed of the traveling motor 36. Further, the system controller 51 controls the rotation speed N of the electric motor 39 in accordance with the on / off of the energy saving mode switch 20 and the power mode switch 21.

  Then, the rotational speed control processing of the electric motor 39 by the system controller 51 will be described with reference to FIG.

  First, when the processing operation starts, it is determined in step 1 whether or not the travel mode switch 19 is turned on and the high speed selection unit 19A is selected. If “NO” is determined in Step 1, the traveling mode switch 19 is turned off and the low speed selection unit 19 </ b> B is selected. Therefore, the process proceeds to Step 2 and the set rotational speed Ns set by the rotational speed setting dial 22. Then, the electric motor 39 is rotated.

  At this time, the set rotational speed Ns is equal to or higher than a predetermined minimum rotational speed Nmin (for example, Nmin = 1300 rpm) and lower than the maximum rotational speed Nmax (for example, Nmax = 2400 rpm). ) It is set within the following range.

  On the other hand, when “YES” is determined in Step 1, the process proceeds to Step 3 to determine whether or not the energy saving mode switch 20 is on. If "YES" is determined in the step 3, the process proceeds to a step 2 so as to rotate the electric motor 39 at the set rotation speed Ns.

  If “NO” is determined in step 3, the normal mode or power mode other than the energy saving mode is selected, so the process proceeds to step 4, and the main battery 40 has an abnormality using the detection signal from the battery controller 49. It is determined whether or not. If "YES" is determined in step 4, since an abnormality such as a voltage drop has occurred in the main battery 40, the voltage abnormality lamp 28 is turned on to alert the operator with an alarm sound or the like, and the process proceeds to step 2. Thus, the electric motor 39 is rotated at the set rotation speed Ns.

  On the other hand, if “NO” is determined in step 4, the voltage normal lamp 27 is turned on, and the process proceeds to step 5 to determine whether or not the power mode switch 21 is on. If “NO” is determined in step 5, the normal mode is selected. Accordingly, the process proceeds to step 6 to determine whether or not the operation amount θ of the travel lever / pedal device 29 is greater than the first threshold value H. judge.

  At this time, the first threshold value H is used to determine whether or not the rotational speed N of the electric motor 39 is automatically increased according to the operation amount θ. It is set to a value that is closer to the maximum tilt position than the intermediate position between the neutral position and the maximum tilt position.

  The first threshold value H has a hysteresis characteristic for preventing chattering as shown in FIG. Specifically, at the time of the tilting operation in which the operation amount θ increases, the first threshold value H is set to the rising determination value H1. On the other hand, at the time of the return operation in which the operation amount θ decreases, the first threshold value H is set to the falling determination value H2 having a value smaller than the rising determination value H1.

  When the determination at step 6 is “NO”, the operation amount θ of the travel lever / pedal device 29 is smaller than the first threshold value H. Therefore, the process proceeds to step 7 where the electric motor 39 is set at the set rotational speed Ns. Rotate.

  On the other hand, when “YES” is determined in step 6, since the operation amount θ of the travel lever / pedal device 29 is larger than the first threshold value H, the operator requests the vehicle to travel at a high speed. It is thought that. Therefore, the process proceeds to step 8 where the rotational speed N of the electric motor 39 is increased and rotated at the maximum rotational speed Nmax.

  If “YES” is determined in step 5, the power mode is selected, so the process proceeds to step 9 and whether or not the operation amount θ of the travel lever / pedal device 29 is greater than the second threshold value L. Determine whether.

  At this time, the second threshold value L is used to determine whether or not the rotational speed N of the electric motor 39 is automatically increased according to the operation amount θ. Is also set to a small value (L <H). Similarly to the first threshold value H, the second threshold value L has a hysteresis characteristic as shown in FIG. Specifically, during the tilting operation in which the operation amount θ increases, the second threshold value L is set to the rising determination value L1. On the other hand, during the return operation in which the operation amount θ decreases, the second threshold value L is set to the falling determination value L2 that is smaller than the rising determination value L1.

  When the determination at step 9 is “NO”, the operation amount θ of the travel lever / pedal device 29 is smaller than the second threshold value L. Therefore, the routine proceeds to step 7 where the electric motor 39 is set at the set rotational speed Ns. Rotate.

  On the other hand, when “YES” is determined in step 9, the operation amount θ of the travel lever / pedal device 29 is larger than the second threshold value L, and therefore the process proceeds to step 8 to rotate the electric motor 39. The number N is increased and rotated at the maximum rotation number Nmax. When Steps 2, 7, and 8 are completed, the process returns to Step 1 and the processes after Step 1 are repeated.

  Next, a specific example when the rotational speed control process of the electric motor 39 in the energy saving mode, the normal mode, and the power mode is performed will be described with reference to FIGS.

  In the energy saving mode shown in FIG. 10, since the energy saving mode switch 20 is turned on, the system controller 51 controls the inverter 42 to turn on the electric motor 39 at the set rotational speed Ns set by the rotational speed setting dial 22. Rotate. In this case, even if the operation amount θ of the travel lever / pedal device 29 is changed, the rotational speed N of the electric motor 39 is maintained at the set rotational speed Ns. In the energy saving mode, the set rotational speed Ns is set in a range between a predetermined rotational speed N0 and a minimum rotational speed Nmin that are lower than the maximum rotational speed Nmax. FIG. 10 shows a case where the set rotational speed Ns is set to the minimum rotational speed Nmin.

  The electric motor 39 and the hydraulic pump 33 rotate at the set rotation speed Ns, and the hydraulic pump 33 discharges pressure oil corresponding to the set rotation speed Ns. Thereby, the traveling motor 36 is driven to rotate in accordance with the flow rate of the pressure oil from the hydraulic pump 33 to cause the vehicle to travel.

  In the normal mode shown in FIG. 11, both the energy saving mode switch 20 and the power mode switch 21 are turned off. FIG. 11 shows a state in which the travel mode switch 19 is turned on and the high speed selection unit 19A is selected. For this reason, the capacity variable portion 36A of the travel motor 36 is set to the small capacity position.

  In this normal mode, the system controller 51 automatically changes the rotation speed N of the electric motor 39 in accordance with the operation amount θ of the travel lever / pedal device 29. More specifically, when the traveling lever / pedal device 29 is in the neutral position, the system controller 51 controls the inverter 42 to rotate the electric motor 39 at the set rotational speed Ns set by the rotational speed setting dial 22. Let In the normal mode, as in the energy saving mode, the set rotational speed Ns is set in a range between a predetermined rotational speed N0 and a minimum rotational speed Nmin that are lower than the maximum rotational speed Nmax. FIG. 11 shows a case where the set rotational speed Ns is set to the minimum rotational speed Nmin.

  Next, when the operator operates the traveling lever / pedal device 29 and the operation amount θ exceeds the first threshold value H (rising judgment value H1) (θ> H1), the system controller 51 turns the inverter 42 on. By controlling, the rotational speed N of the electric motor 39 is increased. As a result, the electric motor 39 and the hydraulic pump 33 rotate at the maximum rotational speed Nmax, and the rotational speed of the traveling motor 36 increases according to the flow rate of the pressure oil from the hydraulic pump 33, so that the vehicle travels at a high speed.

  Further, when the operator returns the traveling lever / pedal device 29 and the operation amount θ becomes smaller than the first threshold value H (falling judgment value H2) (θ <H2), the system controller 51 displays the inverter 42. Is controlled to reduce the rotational speed N of the electric motor 39. As a result, the electric motor 39 and the hydraulic pump 33 rotate at the set rotational speed Ns, and the rotational speed of the traveling motor 36 is reduced according to the flow rate of the pressure oil from the hydraulic pump 33, so that the traveling speed of the vehicle decreases.

  In the power mode shown in FIG. 12, the power mode switch 21 is turned on. Further, FIG. 12 shows a state where the travel mode switch 19 is turned on and the high speed selection unit 19A is selected, as in FIG. For this reason, the capacity variable portion 36A of the travel motor 36 is set to the small capacity position.

  Also in this power mode, as in the normal mode shown in FIG. 11, the system controller 51 automatically changes the rotational speed N of the electric motor 39 in accordance with the operation amount θ of the travel lever / pedal device 29. More specifically, when the traveling lever / pedal device 29 is in the neutral position, the system controller 51 controls the inverter 42 to rotate the electric motor 39 at the set rotational speed Ns set by the rotational speed setting dial 22. Let

  However, in the power mode, the set rotational speed Ns can be set to a higher value than in the normal mode. That is, in the power mode, unlike the normal mode and the energy saving mode, the set rotational speed Ns can be set in a range between the maximum rotational speed Nmax and the minimum rotational speed Nmin. For this reason, the set rotational speed Ns in the power mode can be set to a value faster than the predetermined rotational speed N0 that is the upper limit value in the normal mode. FIG. 12 shows a case where the set rotational speed Ns is set to 2200 rpm, which is faster than 1800 rpm, which is the predetermined rotational speed N0.

  Next, when the operator operates the travel lever / pedal device 29 and the operation amount θ exceeds the second threshold value L (rise determination value L1) (θ> L1), the system controller 51 turns the inverter 42 on. By controlling, the rotational speed N of the electric motor 39 is increased. As a result, the electric motor 39 and the hydraulic pump 33 rotate at the maximum rotational speed Nmax, and the rotational speed of the traveling motor 36 increases according to the flow rate of the pressure oil from the hydraulic pump 33, so that the vehicle travels at a high speed.

  At this time, the second threshold value L in the power mode is set to a value smaller than the first threshold value H in the normal mode. For this reason, in the power mode, the rotational speed N of the electric motor 39 can be increased with a smaller operation amount θ than in the normal mode.

  When the operator returns the traveling lever / pedal device 29 and the operation amount θ becomes smaller than the second threshold value L (falling determination value L2) (θ <L2), the system controller 51 causes the inverter 42 to Is controlled to reduce the rotational speed N of the electric motor 39. As a result, the electric motor 39 and the hydraulic pump 33 rotate at the set rotational speed Ns, and the rotational speed of the traveling motor 36 is reduced according to the flow rate of the pressure oil from the hydraulic pump 33, so that the traveling speed of the vehicle decreases.

  Thus, according to the present embodiment, in the energy saving mode in which the energy saving mode switch 20 is turned on, the system controller 51 is set by the rotation speed setting dial 22 regardless of the traveling operation of the traveling lever / pedal device 29. The electric motor 39 is driven at the rotation speed Ns. For this reason, when excavation work or the like is performed with the vehicle stopped, the power consumption of the main battery 40 can be reliably suppressed by setting the set rotational speed Ns to, for example, the minimum rotational speed Nmin. The operating time can be extended.

  On the other hand, in the normal mode or power mode in which the energy saving mode switch is turned off, the system controller 51 is in a state where the high speed selection unit 19A of the driving mode switch 19 is selected and the driving lever / pedal device 29 is in the neutral position. The electric motor 39 is driven at the set rotational speed Ns set by the rotational speed setting dial 22 to increase the rotational speed N of the electric motor 39 when the travel lever / pedal device 29 is operated. As a result, when the vehicle is driven, if the operator turns on the travel mode switch 19 in advance and selects the high speed side, the rotational speed N of the electric motor 39 can be obtained simply by operating the travel lever / pedal device 29. Can be raised automatically. Further, when the traveling lever / pedal device 29 returns to the neutral position, the rotational speed N of the electric motor 39 can be automatically reduced to the set rotational speed Ns. For this reason, for example, even when the vehicle is traveling at a high speed, a special operation for increasing the rotational speed N of the electric motor 39 is not necessary, and it is only necessary to travel the travel lever / pedal device 29, thus simplifying the operation. Workability can be improved.

  Further, the rotation speed setting dial 22 can set the rotation speed Ns within the range of the maximum rotation speed Nmax of the electric motor 39 when the power mode switch 21 is on. For this reason, for example, when performing excavation work under heavy load, if the operator turns on the power mode switch 21, even when the traveling lever / pedal device 29 is in the neutral position, it is within the range of the maximum rotation speed Ns or less. The electric motor 39 can be driven at a high set rotational speed Ns set by an operator, and pressure oil corresponding to a heavy load can be supplied to each cylinder 9-11.

  Further, when the power mode switch 21 is OFF, the rotation speed setting dial 22 can set the rotation speed Ns within a range of a predetermined rotation speed N0 or less, which is lower than the maximum rotation speed Nmax of the electric motor 39. . For this reason, when the load is light, the set rotational speed Ns is set to a value lower than the predetermined rotational speed N0 that is lower than the maximum rotational speed Nmax. Consumption can be suppressed.

  Further, in the normal mode in which both the energy saving mode switch 20 and the power mode switch 21 are turned off, the system controller 51 exceeds the first threshold value H that is the operation amount θ of the travel lever / pedal device 29. In this case, the rotational speed N of the electric motor 39 is increased. Therefore, in the normal mode, when the operation amount θ of the travel lever / pedal device 29 is smaller than the first threshold value H, the rotational speed N of the electric motor 39 is maintained at the set rotational speed Ns. At this time, the hydraulic pump 33 driven by the electric motor 39 supplies pressure oil corresponding to the low-speed traveling of the vehicle to the traveling motor 36. When the operation amount θ of the travel lever / pedal device 29 is larger than the first threshold value H, the rotational speed N of the electric motor 39 is increased. As a result, the hydraulic pump 33 driven by the electric motor 39 can supply the traveling motor 36 with pressure oil corresponding to the high-speed traveling of the vehicle.

  On the other hand, in the power mode in which the power mode switch 21 is turned on, the system controller 51 increases the rotation speed N of the electric motor 39 when the travel lever / pedal device 29 is traveled exceeding the second threshold value L. It was set as the structure made to do. Therefore, in the power mode, when the operation amount θ of the travel lever / pedal device 29 is smaller than the second threshold value L, the rotation speed N of the electric motor 39 is maintained at the set rotation speed Ns. When the operation amount θ of the travel lever / pedal device 29 is larger than the second threshold value L, the rotational speed N of the electric motor 39 is increased. Thereby, the hydraulic pump 33 driven by the electric motor 39 can supply pressure oil corresponding to the traveling speed of the vehicle to the traveling motor 36 as in the normal mode.

  Furthermore, the second threshold value L is smaller than the first threshold value H. For this reason, in the power mode, the rotational speed N of the electric motor 39 is increased with a small operation amount θ compared to the normal mode, so that the vehicle can be driven at high speed quickly.

  Further, the travel mode switch 19, the energy saving mode switch 20, the power mode switch 21 and the rotation speed setting dial 22 are configured to be attached to the console 16 disposed on the side of the driver's seat 12. Therefore, the operator can operate the travel mode switch 19, the energy saving mode switch 20, the power mode switch 21, and the rotation speed setting dial 22 while sitting on the driver's seat 12. Can be switched quickly.

  Further, when the battery controller 49 detects an abnormality in the main battery 20, the system controller 51 uses the electric motor 39 at the set rotational speed Ns set by the rotational speed setting dial 22 regardless of the travel operation of the travel lever / pedal device 29. Is configured to be driven. For this reason, for example, in a situation where it is inappropriate to drive the electric motor 39 at high speed, such as insufficient charging of the main battery 40, the rotation speed N of the electric motor 39 can be maintained at the set rotation speed Ns. .

  In the above embodiment, steps 2 and 3 in FIG. 7 show a specific example of the energy saving mode driving device, and steps 4 to 8 show a specific example of the non-energy saving mode driving device. Further, steps 5 to 8 in FIG. 7 show a specific example of the normal mode processing device, steps 5 and 7 to 9 in FIG. 7 show a specific example of the power mode processing device, and steps 4 and 2 in FIG. Shows a specific example of the battery abnormality processing apparatus.

  Moreover, in the said embodiment, it was set as the structure provided with three operation modes, the energy saving mode switched according to ON / OFF of the energy saving mode switch 20 and the power mode switch 21, normal mode, and power mode. However, the present invention is not limited to this, and for example, the power mode switch 21 may be omitted, and only two operation modes of an energy saving mode and a normal mode that are switched only by the energy saving mode switch 20 may be provided. In this case, in the normal mode, the set rotational speed Ns may be set up to the maximum rotational speed Nmax.

  In the above embodiment, the step-up / step-down chopper 46 that doubles as a step-up circuit and a step-down circuit is provided between the main battery 40 and the inverter 42. However, the present invention is not limited thereto, and a booster circuit and a step-down circuit may be separately provided.

In the embodiment, the main battery 40 outputs a DC voltage of 160 V _DC , and the electric motor 39 is driven by three-phase AC power of 200 V _AC . However, these voltage values are not limited to the values shown in the embodiment, and may be set as appropriate according to the specifications of each battery or electric motor.

  Furthermore, in the above-described embodiment, a track-type hydraulic excavator has been described as an example of the electric construction machine. However, the present invention is not limited thereto, and a hydraulic pump such as a wheel-type hydraulic excavator is used. It can be widely applied to other construction machines that run on the road.

2 Lower traveling body 3 Upper turning body 12 Driver's seat 16 Right console (console)
19 Travel mode switch 20 Energy saving mode switch 21 Power mode switch 22 Rotation speed setting dial (Rotation speed setting device)
29 Traveling lever / pedal device (traveling operation device)
33 Hydraulic pump 36 Traveling motor (traveling hydraulic motor)
38 Traveling speed switching solenoid valve (capacity switching valve)
39 Electric motor 40 Main battery 42 Inverter 46 Buck-boost chopper (boost circuit)
49 Battery controller 51 System controller (rotation speed control device)

Claims (5)

A self-propelled vehicle body with a driver's seat,
A main battery provided on the vehicle body;
A booster circuit for boosting a DC voltage supplied from the main battery;
An inverter that converts DC power supplied from the booster circuit to AC power;
An electric motor driven by AC power supplied from the inverter;
A hydraulic pump driven by the electric motor;
A variable displacement travel hydraulic motor that is driven by the hydraulic pressure of the hydraulic pump, and that travels the vehicle body at a high speed or a low speed in accordance with a change of capacity by a capacity switching valve;
A travel operation device provided on the vehicle body for controlling the travel hydraulic motor in accordance with a travel operation of an operator;
A travel mode switch for switching between a capacity switching valve of the travel hydraulic motor and selecting either high speed or low speed as the travel speed of the vehicle body;
A rotational speed setter for setting the rotational speed of the electric motor;
An energy saving mode switch for suppressing power consumption of the main battery;
A rotation speed control device that controls the inverter according to the travel mode switch and the energy saving mode switch, and controls the rotation speed of the electric motor;
When the energy saving mode switch is switched to the energy saving mode, the rotation speed control device saves energy by driving the electric motor at the set rotation speed set by the rotation speed setting device regardless of the travel operation of the travel operation device. A mode drive;
When the energy-saving mode switch is switched to the non-energy-saving mode, the set rotational speed set by the rotational speed setter when the traveling operation device is in the neutral position with the high-speed side selected by the traveling mode switch An electric construction machine comprising: a non-energy-saving mode drive device that drives the electric motor to increase the rotation speed of the electric motor when the travel operation device is traveled. A power mode switch that enables the electric motor to be driven at a maximum rotational speed when the travel operation device is in a neutral position;
When the power mode switch is switched to the power mode, the rotational speed setter enables the set rotational speed to be set within a range equal to or less than the maximum rotational speed of the electric motor, and the power mode switch is set to a non-power mode. 2. The electric construction machine according to claim 1, wherein, when switched, the set rotational speed can be set within a range of a predetermined rotational speed that is lower than a maximum rotational speed of the electric motor. The non-energy-saving mode drive device rotates the electric motor when the operation amount of the travel operation device exceeds a predetermined first threshold when the power mode switch is switched to the non-power mode. A normal mode processing device for increasing the number;
When the power mode switch is switched to the power mode, the rotational speed of the electric motor is increased when the operation amount of the traveling operation device exceeds a second threshold value that is smaller than the first threshold value. The electric construction machine according to claim 2, comprising a power mode processing device.   4. The electric construction machine according to claim 2, wherein the travel mode switch, the energy saving mode switch, the power mode switch, and the rotation speed setting device are configured to be attached to a console disposed in the vicinity of the driver's seat. A battery controller for detecting an abnormality of the main battery;
When the battery controller detects an abnormality of the main battery by the battery controller, the non-energy-saving mode driving device drives the electric motor at the set rotational speed set by the rotational speed setter regardless of the traveling operation of the traveling operation device. The electric construction machine according to claim 1, 2, 3, or 4, comprising a battery abnormality processing device.

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