JP2009197514A - Electrically-driven working machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrically-driven working machine with excellent reliability, which can increase the amount of work and a period of operating time by effectively utilizing a limited battery capacity. <P>SOLUTION: This electrically-driven working machine is equipped with electric motors 103 and 106 which serve as main power sources for an actuator, and a battery 20 which serves as a driving power source for the electric motors 103 and 106. The electrically-driven working machine, which is equipped with a control unit 100, measures a battery voltage of the battery 20, determines the remaining capacity of the battery 20 from the measured battery voltage, and changes the maximum output of the actuator depending on the result of the determination of the remaining capacity of the battery. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electrically driven work machine that drives an electric motor, which is a main power source of an actuator, using a battery as a drive power source, and in particular, effectively uses a limited battery capacity to extend the amount of work and operation time. It relates to means to do.

  2. Description of the Related Art Conventionally, an electrically driven work machine is known in which an electric motor is mounted as a drive source of a hydraulic pump, and electric power is supplied to the electric motor from an in-vehicle battery to drive a necessary hydraulic actuator (for example, Patent Document 1). reference).

  The technique described in Patent Document 1 relates to an excavator equipped with a battery, and supplies electric power from the battery to a plurality of electric motors via inverters, and drives each of these electric motors to drive a hydraulic pump. The pressure oil discharged from the cylinder is supplied to a cylinder of an actuator provided in the link mechanism to perform work such as excavation. The excavator is provided with means for detecting the remaining amount of the battery (power capacity). When it is detected that the remaining amount has decreased and reached a preset threshold value, the power is supplied from the battery. There is provided alarm means for restricting the operation of the actuator by limiting and issuing an alarm informing that effect. This threshold value represents the remaining battery level at which the excavator can move to the charging facility by itself, and the excavator can be prevented from getting stuck by moving the excavator to the charging facility when an alarm is generated.

  This type of battery-powered work machine does not emit any exhaust gas and can significantly reduce noise and vibration, so there are restrictions on underground work and noise and vibration where engine exhaust cannot be performed. It is suitable for work in urban areas, and unlike electric drive type work machines that use commercial power, there is no need to connect the power source and electric motor via a power cable. Has the advantage that it is not limited to the power cable.

  By the way, a battery having a large output for driving a large work machine such as an excavator is not only expensive, but also has a lower energy output per weight than light oil used for driving an engine. How to effectively use a battery with a limited capacity that can be mounted on a vehicle to extend the amount of work and operating time is a big problem.

In Patent Document 2, as a means for solving such a problem, the increase / decrease in the battery capacity is monitored by the monitoring means, and the increase / decrease in the output to the work equipment is controlled for each preset area based on the monitoring result. A technique for driving a device is disclosed.
JP-A-11-107320 JP 2004-189409 A

  However, since the technique disclosed in Patent Document 2 controls increase / decrease in the output to the work equipment in accordance with the power supply capacity remaining in the battery, for example, the load on the battery varies greatly like an excavator. When applied to a work machine, if the load applied to the battery is large, even if the power capacity value is sufficient, a sufficient battery output cannot be obtained, and problems such as the actuator not operating normally may occur. In addition, from this, in order to operate the actuator normally regardless of the size of the load, a power capacity value larger than necessary must be set as a threshold value, and the power capacity cannot be used effectively. There is also.

  The present invention has been made to solve the problems of the prior art, and its purpose is an electric drive that is excellent in reliability and that can effectively use a limited battery capacity to extend the work amount and the operation time. It is to provide a type work machine.

  In order to achieve the above object, the present invention provides an electric drive work machine including an actuator, an electric motor that is a main power source of the actuator, and a battery that is a drive power source of the electric motor. Battery voltage measuring means for measuring, battery remaining amount determining means for determining the battery remaining amount of the battery from the battery voltage measured by the battery voltage measuring means, and the actuator according to a determination result of the battery remaining amount determining means Output control means for changing the maximum output.

  As described above, a work machine such as an excavator has a large load on the battery depending on the operating state. Therefore, the power capacity of the mounted battery is measured, and it is determined that there is sufficient power capacity. Even in this case, when the load applied to the battery is large and the voltage drop is large, sufficient battery output cannot be obtained and the actuator cannot be operated normally. In addition, this makes it impossible to fully utilize the power capacity of the battery. On the other hand, when the battery voltage is measured as the remaining battery level, a threshold value for changing the maximum output of the actuator can be set in consideration of the voltage drop according to the load applied to the battery. Therefore, it is possible to obtain an appropriate output in accordance with the maximum output (maximum torque or maximum speed) of the actuator. In addition, since an appropriate threshold value can be set in consideration of a voltage drop at the time of load, the power capacity of the battery can be fully utilized without waste, and the work amount and operating time can be extended.

  Secondly, in the first electrically driven work machine according to the present invention, the battery remaining amount determination means includes an actuator drive limit voltage at a maximum load of the battery and a value higher than the actuator drive limit voltage. The set threshold value is stored, and the battery remaining amount determining means determines the battery remaining amount by comparing the battery voltage measured by the battery voltage measuring means with the threshold value, and the output control means When the battery remaining amount determining means determines that the measured battery voltage has dropped below the threshold value, the maximum output of the actuator is greater than the threshold value. It is characterized by limiting to a lower value than the case.

  According to such a configuration, it is possible to set an optimum threshold in consideration of a voltage drop when a load is applied to the actuator, so that normal operation of the actuator can be ensured and power supply capacity can be effectively used.

  Thirdly, in the first electrically driven work machine according to the present invention, the threshold value is set in the battery remaining amount determining means in multiple steps or steplessly, and the battery voltage measured by the battery remaining amount determining means is set. Is determined in which stage of the thresholds set in the multi-stage or stepless, and the output control means changes the maximum output of the actuator according to the determination result of the battery remaining capacity determination means. Features.

  According to such a configuration, the maximum output of the actuator can be limited step by step or steplessly in accordance with the decrease in the remaining battery level, so that the actuator output can be more strictly limited and more qualified. Effective use of power supply capacity can be achieved.

  Fourthly, in the first electrically driven work machine according to the present invention, the battery remaining amount determining means has an actuator drive limit voltage at a maximum load of the battery and a value higher than the actuator drive limit voltage. The set threshold value is stored, and the battery remaining amount determining means determines the battery remaining amount by comparing the battery voltage measured by the battery voltage measuring means with the threshold value, and the output control means Counts the number of times the battery remaining capacity determining means determines that the measured battery voltage has fallen below the threshold, and increases the maximum output of the actuator stepwise as the count increases. It is characterized by limiting to a low value.

  When the actuator is driven, a load is applied to the battery and a voltage drop occurs. When the actuator is stopped, the load applied to the battery is removed and a voltage rise occurs. The battery voltage decreases every time such voltage fluctuation occurs. Therefore, if the cumulative number of voltage drops is counted and the maximum output of the actuator is limited to a lower value step by step as the number of times increases, it is possible to prevent the actuator from being driven beyond the actuator drive limit voltage. Can ensure the normal operation of the work machine.

  According to the present invention, since the battery voltage is measured as the remaining battery level, a threshold value for changing the maximum output of the actuator can be set in consideration of a voltage drop according to the load applied to the battery, and the remaining battery level is always set. The actuator can be driven with an appropriate output according to the above. In addition, since an appropriate threshold value can be set in consideration of a voltage drop at the time of load, the power supply capacity of the battery can be fully utilized without waste, and the amount of work and operation time can be extended.

<First Embodiment>
Hereinafter, a first embodiment of an electrically driven work machine according to the present invention will be described taking a battery-type electric excavator as an example.

  FIG. 1 is a diagram illustrating a state during charging of a battery-type electric excavator according to the embodiment, where 1 is a battery-type electric excavator, and 2 is a power supply unit that supplies electric power for charging to the battery-type electric excavator 1. ing. The battery-type electric excavator 1 includes an upper swing body 10, a lower traveling body 11, a front member 12 having a boom 12 a, an arm 12 b and a bucket 12 c, and a battery 20 mounted inside the upper swing body 10. Composed. On the other hand, the external power supply unit 2 includes an external power source 21 such as a commercial high-voltage power source or a generator, and a power cable 21 a that connects the battery 20 and the external power source 21.

  One end of the boom 12a is pin-coupled to the upper swing body 10, and rotates in a vertical plane around the pin coupling portion. One end of the arm 12b is pin-coupled to the tip of the boom 12a, and the arm 12b rotates in a vertical plane around the pin-coupled portion. One end of the bucket 12c is pin-coupled to the tip of the arm 12b, and the bucket 12c rotates in a vertical plane around the pin-coupled portion. These front members 12a, 12b, and 12c rotate by expanding and contracting a boom hydraulic cylinder, an arm hydraulic cylinder, and a bucket hydraulic cylinder (not shown) provided for each front member. The driver operates a control lever or the like provided in the driver's cab and appropriately expands and contracts each of the hydraulic cylinders to perform necessary work such as excavation and loading.

  Between the upper turning body 10 and the lower traveling body 11, a turning wheel 13 that is rotated by an electric motor 106 for turning (see FIG. 2) is provided, and the driver operates an operation lever or the like provided in the cab. Is operated to drive the turning electric motor 106 and thereby turn the turning wheel 13 to rotate the upper turning body 10 on the lower traveling body 11. Further, the lower traveling body 11 is provided with a traveling crawler belt 11a driven by a traveling hydraulic motor (not shown), and the driver operates the operating lever provided in the driver's cab to drive the traveling hydraulic motor. Then, the battery-powered excavator 1 is caused to travel forward or backward by driving the traveling crawler belt 11a. The traveling crawler belt 11a and the traveling hydraulic motor that drives the traveling crawler belt 11a are provided on both the left and right sides of the lower traveling body 11, respectively.

  The battery-type electric excavator 1 includes a hydraulic pump 102 that supplies pressure oil to the hydraulic cylinders and the traveling hydraulic motor (in the present specification, these may be collectively referred to as “hydraulic actuators”), and the hydraulic pump 102. The electric motor 103 to drive (refer FIG. 2) is mounted, and the battery 20 is used as a power supply of the vehicle-mounted electric equipment containing this electric motor.

  The upper swing body 10 is provided with an external power connection port (not shown) for connecting the power cable 21a. By connecting the power cable 21a of the external power supply source 2 to the external power connection port, an external power source is connected. The external power source 21 of the supply source 2 can be connected to the battery 20 charging device. The power cable 21a is configured to be detachable from the external power supply connection port. When the power cable 21a is connected to the external power supply connection port, the battery 20 can be charged by the external power supply 21 via the charging device. After the battery charge amount exceeds a predetermined amount, the battery 20 becomes a driving power source for each actuator.

  FIG. 2 is a system block diagram showing the configuration of the power management unit mounted on the battery-powered excavator 1 according to the embodiment. As is clear from this figure, the power management unit of this example includes the control device 100, The battery 20, the battery voltage measuring device 22 for measuring the battery voltage, the display device 101 for displaying necessary information including the battery voltage to the driver, the traveling hydraulic motor for driving the lower traveling body 11, and the boom 12a are driven. Boom driving hydraulic cylinder, arm driving hydraulic cylinder driving arm 12b, hydraulic pump 102 supplying pressure oil to bucket driving hydraulic cylinder driving bucket 12c, and first electric motor 103 driving hydraulic pump 102 A first inverter 104 that supplies an alternating current to the first electric motor 103, and an upper portion relative to the lower traveling body 11. A turning electric motor (second electric motor) 106 for turning the turning body 10, a second inverter 107 for supplying an alternating current to the second electric motor 106, and a charging device 108 for the battery 20 to which the external power source 21 is connected, The power source switching unit 109 switches the driving power source of the battery-powered excavator 1 to the battery 20 or the external power source 21 or both according to a control signal from the control device 100.

  As shown in FIGS. 2 and 3, the control device 100 includes a key switch signal SD <b> 1 output from a key switch (not shown) that is operated by the driver to start, start, and stop the battery-powered excavator 1. Lever operation amount signal SD2 output from the operation lever operated to execute the work, lock lever signal SD3 output from the lock lever operated by the driver to prevent erroneous operation of the operation lever, battery voltage measuring device 22 The battery remaining amount signal SD4 output from the power supply 21 and the external power supply connection signal SD5 output from the charging device 108 when the power cable 21a is connected to the external power supply connection port, and the display device 101 Display data signal SC1 and actuator command signal applied to the first and second inverters 104 and 107. SC2 and SC3, output unit 120 that outputs power supply switching signal SC4 to be applied to power supply switching unit 109, and the remaining amount of battery 20 (battery remaining amount) are determined based on the battery voltage measured by battery voltage measuring device 22. In addition, a determination / control unit 130 that changes the maximum output (maximum torque or maximum speed, etc.) of each hydraulic actuator according to the determined remaining battery level, the remaining battery level threshold, and the remaining battery level are the threshold values. A ROM 140 that stores the maximum output of each actuator when the above is the case and the maximum output of each actuator when the battery remaining amount is less than or equal to the threshold, and a program of processing executed by the determination / control unit 130 It is mainly composed of a stored RAM 150. As shown in FIGS. 2 and 3, for example, a control device power supply VS of 24 V is supplied to the control device 100 and driven.

  As shown in FIG. 4, the ROM 140 stores, for the battery 20, a change in battery voltage at no load and a change in battery voltage at the maximum load according to the remaining battery level. Is set to a predetermined voltage value equal to or higher than the actuator drive limit voltage V0. In this example, as shown in FIG. 4, the lower limit voltage V1, which is the first threshold value, is set to a value higher than the actuator drive limit voltage V0, and the second threshold value is set to a value higher than the lower limit voltage V1. A return voltage V2 is set.

  Further, the ROM 140 stores a change in the maximum output of the actuator in accordance with the change in the battery voltage, as shown in FIG. In this example, as shown in FIG. 5, the lower limit voltage V1 is set to a value that is 30% lower than the maximum voltage value of the battery 20 at the time of load, and the battery voltage at the time of load is lower than the lower limit voltage V1. The maximum output of the actuator is reduced from 100% to 40%.

  Hereinafter, the operation of the battery-powered excavator 1 according to the present embodiment will be described with reference to FIGS. 6 and 7.

  When the battery-powered excavator 1 is in the drive stop state (step S1 in FIG. 6), when the driver inserts the activation key into the key hole installed in the cab and turns the threshold switch from the OFF state to the ON state. The auxiliary power supply voltage is supplied from the control device power supply VS from the control device 100 to be in an operation (ON) state, and the control device 100 supplies a power supply voltage to the display device 101 to make it active. When the activation key is further rotated from this state to start the key switch, the key switch signal SD1 is supplied to the control device 100 from this key switch. In response to this, the control device 100 outputs the switching control signal SC4 to the power switching unit 109, and the power switching unit 109 is set so that the drive power voltage of the electric motors 103, 106 is supplied from the battery 20 to the inverters 104, 107. Switch. As a result, the DC power supply voltage from the battery 20 is supplied to each of the inverters 104 and 107 via the power supply switching unit 109, and the battery-powered excavator 1 is operated so as to be operable by operating the operation lever (step in FIG. 6). S2).

  In this state, when the driver releases the start key, the key switch is turned on, but the operating state is maintained as it is. In addition, when the key switch is turned from the ON state to the OFF state by operating the start key in the operating state, the key switch signal SD1 is not supplied from the key switch to the control device 100. Therefore, the control device 100 switches to the power supply switching unit 109. A control signal SC4 is sent to switch it to the OFF (open) state. As a result, power is not supplied to the inverters 104 and 107, and even if the operation lever is operated, the battery-powered excavator 1 is not operated (step S3 in FIG. 6). Accordingly, the supply of the auxiliary power supply voltage from the control device power supply VS to the control device 100 is also terminated.

  When the battery-operated excavator 1 is in an operating state and the operation lever is operated by the driver, a lever operation amount signal SD2 corresponding to the operation amount of the operation lever is supplied to the control device 100. Thus, control device 100 sends actuator command signals SC2 and SC3 to inverters 104 and 107 corresponding to the operated operation lever, and performs an operation corresponding to the operation amount. Further, when the lock lever is operated, the lock lever signal SD3 is supplied to the control device 100, and the control device 100 receives this and outputs a switching control signal SC4 to the power supply switching unit 109 to turn it off. As a result, the hydraulic switch does not operate even when the lever is operated while the key switch is in the ON state, and the battery-operated excavator 1 is prevented from being illegally operated due to inadvertent or unintentional lever operation. can do.

  When the battery 20 or the external power supply 21 is connected, the inverters 104 and 107 convert the DC power supply voltage from the charging device 108 into an AC voltage, and create the AC power supply voltage of the electric motors 103 and 106 connected thereto. The operation is ON / OFF controlled according to the actuator command signals SC2 and SC3 from the control device 100, and the duty ratio and polarity of the AC power supply voltage are controlled according to the operation amount of the operation lever. The Thereby, the rotation speed and rotation direction of each electric motor 103,106 are controlled. The hydraulic pump 102 discharges pressure oil having a pressure corresponding to the rotation speed of the electric motor 103, and drives the hydraulic actuator in a direction corresponding to the operation direction of the operation lever at a speed corresponding to the operation amount. The maximum output (maximum torque or maximum speed) of each hydraulic actuator is regulated by the rotational speed of the electric motor 103 and, in turn, the power supply voltage value supplied to the electric motor 103. Similarly, the maximum output (maximum speed) of the swivel wheel 13 is regulated by the rotational speed of the electric motor 106 and, consequently, the power supply voltage value supplied to the electric motor 106.

  As shown in FIG. 7 (a), the battery voltage of the battery 20 decreases when a load is applied, and decreases when the load is removed, and increases when the load is removed. When the battery voltage when the load is applied is maintained at the lower limit voltage V1 or more stored in the ROM 140 of the control device 100, the determination / control unit 130 outputs to the actuator as shown in FIG. 7B. Without limitation (output limitation OFF), the outputs of the first electric motor 103 and the second electric motor 106 are the normal outputs shown in FIG. 7C, that is, the charge amount of the battery 20 is full (100%). The same output as the case is maintained (step S21 in FIG. 6). As a result, the hydraulic actuator and the swivel wheel 13 can be operated at the maximum torque and the maximum speed that are rated. On the other hand, when the battery voltage when the load is applied falls below the lower limit voltage V1, the determination / control unit 130 places an output limit on the actuator (output limit) as shown in FIG. ON), the outputs of the first electric motor 103 and the second electric motor 106 are reduced to the limit output shown in FIG. 7C, that is, 40% stored in the ROM 140 of the control device 100 (step S22 in FIG. 6). ). Thereby, the drive of the battery-type electric excavator 1 can be secured, the failure of the battery-type electric excavator 1 can be prevented, the power capacity of the battery 20 can be used without waste, and the work amount and the operation time can be reduced. Can be extended. Then, as shown in FIG. 7A, when the battery voltage of the battery 20 recovers to the recovery voltage V2 or more set in the ROM 140 by removing the load, the determination is made as shown in FIG. 7B. The control unit 130 releases the actuator output restriction again (output restriction OFF), and switches the outputs of the first electric motor 103 and the second electric motor 106 to normal output again (step S21 in FIG. 6). When the battery voltage of the battery 20 reaches the actuator drive limit voltage V0 set in the ROM 140, the determination / control unit 130 temporarily stops the power supply to the first electric motor 103 and the second electric motor 106. (Step S23 in FIG. 6). Thereby, generation | occurrence | production of malfunctions, such as malfunctioning, can be prevented.

  When the outputs of the first electric motor 103 and the second electric motor 106 are reduced to the limit output, the display data signal SC1 is output from the control device 100 to the display device 101 in order to notify the driver of this. , To that effect is displayed on the display device 101. Thereby, since it becomes difficult for the driver to feel uncomfortable with respect to the decrease in output, it becomes easier to perform appropriate driving according to the motor output.

  When the power cable 21a of the external power source 21 is connected to the external power source connection port provided in the upper swing body 10 of the battery-type electric excavator 1, an AC voltage is supplied from the external power source 21 to the charging device 108 via the power cable 21a. Where it is converted to a DC voltage. This DC voltage is supplied to the battery 20 via the power supply switching unit 109. Thereby, the battery 20 is charged. The power source switching unit 109 is ON / OFF controlled by a switching control signal SC4 from the control device 100. In addition, when the power cable 21a is connected to the external power source connection port, and the AC voltage is supplied from the external power source 21 to the charging device 108 to generate a DC voltage for charging, the charging device 108 detects this, An external power connection signal SD5 indicating that the cable 21a is connected to the external power supply connection port is generated and supplied to the control device 100.

  The control device 100 takes in the external power connection signal SD5 from the charging device 108 and constantly monitors whether or not the power cable 21a is connected to the external power connection port. When a charging operation switch (not shown) installed in the cab is operated in a state where the power cable 21a is connected to the external power connection port, a charging switch signal SD6 is supplied to the control device 13. The control device 100 generates a switching control signal SC4 based on the charging switch signal SD6 to turn on the power supply switching unit 109 (closed). As a result, the battery 20 is automatically charged by the charging device 108.

  Note that this charging operation switch is a momentary switch that retains the ON or OFF information due to the pushing operation, although it returns to its original state when it is released with the fingertip pressed. Each time this charging operation switch is operated, the power switch 109 is alternately switched between ON and OFF by the charging switch signal SD6 from the control device 100.

  Further, the control device 100 constantly detects the remaining battery level of the battery 20, and detects that the charge amount of the battery 20 is full (100% remaining battery level) during charging by the external power source 21, By generating the switching control signal SC4, the power supply switching unit 109 is turned off. Thereby, charging of the battery 2 is automatically terminated. Even when the power cable 21a is removed from the external power supply connection port, the control device 100 detects this by the external power supply connection signal SD5, generates the switching control signal SC4, and turns off the power supply switching unit 109.

  Since the battery-powered excavator according to the first embodiment measures the battery voltage as the remaining battery level, it sets a threshold value for changing the maximum output of the actuator in consideration of the voltage drop according to the load applied to the battery. Can do. Therefore, the actuator can be driven with an appropriate output corresponding to the remaining battery level at all times, avoiding the inconvenience such as the excavator getting stuck during work, and the power capacity of the battery can be fully utilized without waste, Work volume and operating time can be extended.

Second Embodiment
As shown in FIGS. 8 and 9, the battery-powered excavator according to the second embodiment increases the maximum output of the actuator as the measured battery voltage decreases when the battery voltage falls below a predetermined threshold. It is characterized by a stepless reduction. Although illustration is omitted, as a matter of course, the maximum output of the actuator can be reduced stepwise as the measured battery voltage decreases.

  The battery-type electric excavator of this example sets a plurality of threshold values corresponding to the battery voltage in the ROM 140 (see FIG. 3) of the control device 100, and the measured battery voltage is the threshold value set in the above-described multistage or non-stage. The determination / control unit 130 determines which stage it is in, and the determination / control unit 130 changes the maximum output of the actuator according to the determination result of the battery remaining amount determination means. Since others are the same as those of the battery-type electric excavator according to the first embodiment, description thereof is omitted.

  The battery-type electric excavator according to the second embodiment limits the maximum output of the actuator stepwise or steplessly according to the decrease in the remaining battery level, so that the actuator output can be more strictly limited, The power supply capacity can be effectively used more appropriately.

<Third Embodiment>
As shown in FIG. 10, the battery-type electric excavator according to the third embodiment counts the number of times that the battery voltage has dropped below a predetermined threshold, and gradually increases the maximum output of the actuator as the count number increases. It is characterized by limiting to.

  That is, as shown in FIG. 10A, when the actuator is driven, the battery is loaded with a voltage drop, and when the actuator is stopped, the load applied to the battery is removed and the voltage rises. Happens. The battery voltage after the load is removed gradually decreases every time such voltage fluctuation occurs. Therefore, as shown in FIG. 10 (b), the cumulative number of voltage drops exceeding the lower limit voltage V1 is counted, and as this number increases, the maximum output of the actuator is increased as shown in FIG. 10 (c). By limiting to a low value in stages, it is possible to prevent the actuator from being driven beyond the actuator drive limit voltage, so that normal operation of the work machine can be ensured.

  As shown in FIG. 11, the battery-type electric excavator of this example includes a counter 160 that counts the cumulative number of voltage drops exceeding the lower limit voltage V1 in the control device 100, and a lower limit voltage V1 counted by the counter 160 in the ROM 140. This can be implemented by storing the output limit of the actuator according to the cumulative number of voltage drops exceeding. Since others are the same as those of the battery-type electric excavator according to the first embodiment, description thereof is omitted.

  In the battery-powered excavator according to the third embodiment, the output of the actuator becomes stronger and the maximum output decreases as the remaining amount of the battery decreases and the frequency of falling below the lower limit voltage V1 increases. Since the burden is reduced and the voltage drop is reduced, the normal operation of the actuator can be ensured.

  In each of the above embodiments, a battery-type electric excavator has been described as an example. However, the gist of the present invention is not limited to this and can be applied to any battery-type electric work machine.

It is a lineblock diagram of the battery type electric excavator concerning an embodiment. It is a system block diagram of the power management part which concerns on embodiment. It is a block diagram of the control apparatus which concerns on 1st Embodiment. It is explanatory drawing of the threshold value set to the control apparatus which concerns on 1st Embodiment. It is explanatory drawing of the output restrictions set to the control apparatus which concerns on 1st Embodiment. It is a state transition diagram of the output limitation accompanying the fluctuation | variation of a battery voltage. It is a figure which shows the output limiting system performed with the control apparatus which concerns on 1st Embodiment. It is explanatory drawing of the output restriction | limiting set to the control apparatus which concerns on 2nd Embodiment. It is a figure which shows the output limiting system performed with the control apparatus which concerns on 2nd Embodiment. It is a figure which shows the output limiting system performed with the control apparatus which concerns on 3rd Embodiment. It is a block diagram of the control apparatus which concerns on 3rd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Battery type electric shovel 2 Power supply part 10 Upper turning body 11 Lower traveling body 12 Front member 13 Turning wheel 20 Battery 21 External power supply 21a Electric power cable 22 Battery voltage measuring device 100 Control device 101 Display device 102 Hydraulic pump 103 1st electric motor 104 First Inverter 106 Turning (Second) Electric Motor 107 Second Inverter 108 Charging Device 109 Power Supply Switching Unit 110 Input Unit 120 Output Unit 130 Judgment / Control Unit 140 ROM
150 RAM
160 counter

Claims (4)

In an electrically driven work machine equipped with an actuator, an electric motor that is a main power source of the actuator, and a battery that is a driving power source of the electric motor,
Battery voltage measuring means for measuring the battery voltage of the battery, battery remaining amount determining means for determining the battery remaining amount of the battery from the battery voltage measured by the battery voltage measuring means, and determination by the battery remaining amount determining means An electrically driven work machine comprising output control means for changing a maximum output of the actuator according to a result.   The battery remaining capacity determining means stores an actuator driving limit voltage at the maximum load of the battery and a threshold set to a value higher than the actuator driving limit voltage, and the battery remaining capacity determining means The battery voltage measured by the battery voltage measuring unit is compared with the threshold value to determine the remaining battery level, the output control unit is configured to determine whether the battery remaining level determining unit is the measured battery voltage. The maximum output of the actuator is limited to a lower value than when the measured battery voltage is larger than the threshold value when it is determined that the voltage drops below a threshold value. Electric drive work machine.   The threshold value is set in the battery remaining amount determining means in multiple steps or steplessly, and the step of the threshold set in the multiple steps or steplessly is the battery voltage measured by the battery remaining amount determining means. The electric drive work machine according to claim 1, wherein the output control means changes the maximum output of the actuator in accordance with a determination result of the battery remaining capacity determination means.   The battery remaining capacity determining means stores an actuator driving limit voltage at the maximum load of the battery and a threshold set to a value higher than the actuator driving limit voltage, and the battery remaining capacity determining means The battery voltage measured by the battery voltage measuring unit is compared with the threshold value to determine the remaining battery level, the output control unit is configured to determine whether the battery remaining level determining unit is the measured battery voltage. 2. The electric drive according to claim 1, wherein the number of times determined to be lower than a threshold value is counted, and the maximum output of the actuator is limited to a lower value stepwise as the number of times of counting increases. Type work machine.

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