JP2014148879A - Work machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a work machine capable of preventing a battery from running out of residual capacity within estimated operating time and curbing a decrease in work efficiency beyond necessity.SOLUTION: A work machine comprises: a battery 15; a revolving motor 16 which is driven by power supply from the battery 15; a mode selection switch 29 to set a maximum value of hourly discharge power of the battery 15; a vehicle body controller 11 which controls the hourly discharge power of the battery 15 not more than a value set through the mode selection switch 29 and calculates estimated operating time of a hydraulic shovel on the basis of residual capacity of the battery 15 and the value set through the mode selection switch 29; and a monitor 23 which displays the estimated operating time of the hydraulic shovel calculated by the vehicle body controller 11.

Description

  The present invention relates to a work machine including an electric actuator that is driven by electric power stored in a power storage device.

  In recent years, work machines that drive electric actuators with electric power stored in power storage devices such as capacitors and batteries have been developed from the viewpoint of energy saving. For example, a hybrid construction machine includes a power storage device in addition to an engine, and uses an electric power stored in the power storage device to drive an electric motor (electric actuator), thereby rotating the upper swing body. There is an excavator.

  As a technology related to this type of construction machine, there is one having a work speed control means for limiting the work speed according to the work content when the power of the generator is below a predetermined value, and using the work speed control means. In some cases, the battery deterioration is suppressed by maintaining the electric power consumption of the electric motor to such an extent that the battery is not overdischarged. That is, generally, when an electric actuator is driven when the engine speed is low, it takes a long time to increase the engine speed, and there is a possibility that the power generation amount is temporarily insufficient and a rapid discharge is generated from the battery. In this technique, the work speed control means suppresses the operating speed of the electric actuator to prevent battery deterioration (Japanese Patent Laid-Open No. 2001-3396).

  Another technique is to prevent battery deterioration by suppressing overcharge and overdischarge by changing the amount of discharge and charge of the battery (the amount of power generated by the generator) according to the work content. There is a thing which is aiming at (Unexamined-Japanese-Patent No. 2001-3397).

JP 2001-3396 A JP 2001-3397 A

  Each of the above technologies attempts to suppress battery deterioration in a hybrid work machine by preventing excessive charging / discharging of the battery. However, on the other hand, considering how to effectively use the energy (electric power) stored in the battery, the remaining capacity of the battery can be used in a planned manner according to the scheduled operation time and work contents of the hybrid work machine. Desired. For example, even if the battery is not excessively discharged, if the battery is used too much in a short time, the remaining capacity of the battery may be insufficient with respect to the scheduled operation time. In this case, the electric actuator must be driven by the electric power obtained by driving the generator with the engine in the middle of the work, and the subsequent work requires a lot of fuel, resulting in a decrease in energy efficiency. It becomes. On the other hand, if you work while suppressing the amount of discharge of the battery because you are worried that the battery will run out during the work time, the remaining capacity after the work will be excessive. The stored energy may not be utilized and work efficiency may be reduced.

  The objective of this invention is providing the working machine which can suppress that the remaining capacity of a battery is lose | eliminated within the scheduled operation time, and that work efficiency falls more than necessary.

  (1) In order to achieve the above object, the present invention sets a power storage device, an electric actuator driven by power supply from the power storage device, and a maximum value of discharge power per time of the power storage device. And the discharge power per hour of the power storage device is controlled to be equal to or less than a set value by the input device, and the scheduled operation time of the work machine is calculated based on the remaining capacity of the power storage device and the set value A control device and a display device for displaying a scheduled operation time of the work machine calculated by the control device are provided.

  (2) In the above (1), preferably, the apparatus further includes a generator motor driven by an engine, and the control device, when the required power of the electric actuator exceeds a set value by the input device, Electric power corresponding to a difference between set values is generated by the generator motor and supplied to the electric actuator.

  (3) In the above (1) or (2), preferably, the control device corrects a remaining capacity of the power storage device according to a degree of deterioration of the power storage device, and based on the corrected remaining capacity, The scheduled operation time shall be calculated.

  (4) In any one of the above (1) to (3), preferably, the input device is a mode for selecting one of a plurality of work modes determined according to the work content of the work machine. It is a selection switch, and the maximum value of the discharge power per hour of the power storage device is set according to the work mode selected by the switch.

  (5) In the above (2), preferably, when the required power of the electric actuator is lower than a set value by the input device, the control device stores power corresponding to a difference between the required power and the set value. It is assumed that the engine is assisted and driven from a device to the generator motor.

  ADVANTAGE OF THE INVENTION According to this invention, it can suppress that the remaining capacity of a battery is lose | eliminated within operation scheduled time, and work efficiency falls more than needed.

1 is an external view of a hybrid hydraulic excavator according to an embodiment of the present invention. 1 is a schematic diagram of a drive control system for a hydraulic excavator according to an embodiment of the present invention. The functional block diagram of the vehicle body controller which concerns on embodiment of this invention. The flowchart of the control process of the turning motor 16 performed with the vehicle body controller 11 which concerns on embodiment of this invention. The flowchart of the control processing of the generator motor 10 performed with the vehicle body controller 11 which concerns on embodiment of this invention. The figure which showed typically the change of the request | requirement electric power Wd with respect to the maximum value Wk (k = 1, 3) of the discharge electric power during operation | movement of a hydraulic shovel. The figure which showed typically the change of the electric power actually supplied to the turning motor 16, when the demand electric power Wd changes like FIG. The figure which showed typically the change of the electric power actually supplied to the turning motor 16, when the demand electric power Wd changes like FIG. The figure which shows an example of the time change of the target remaining capacity of the battery 15, and an estimated operation time. The figure which compared the actual battery remaining capacity about the case where SOC is the same and there is no deterioration of a battery (SOH = 100) and deterioration progresses (SOH = 60). The figure which shows an example of the scheduled operation time when the heavy work mode and the light work mode are selected

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an external view of a hybrid hydraulic excavator according to an embodiment of the present invention. The hydraulic excavator shown in this figure includes an articulated work device 1A having a boom 1a, an arm 1b, and a bucket 1c, and a vehicle body 1B having an upper swing body 1d and a lower traveling body 1e.

  The boom 1a is rotatably supported by the upper swing body 1d and is driven by a hydraulic cylinder (boom cylinder) 3a. The arm 1b is rotatably supported by the boom 1a and is driven by a hydraulic cylinder (arm cylinder) 3b. The bucket 1c is rotatably supported by the arm 1b and is driven by a hydraulic cylinder (bucket cylinder) 3c. The upper swing body 1d is driven to rotate by a swing motor (electric motor) 16 (see FIG. 2) which is an electric actuator, and the lower travel body 1e is driven by left and right travel motors (hydraulic motors) 3e and 3f (see FIG. 2). . Driving of the hydraulic cylinder 3a, the hydraulic cylinder 3b, the hydraulic cylinder 3c, and the swing motor 16 is controlled by operating devices 4A and 4B (see FIG. 2) that are installed in the cab of the upper swing body 1d and output a hydraulic signal. Is done.

  FIG. 2 is a schematic diagram of a drive control system for a hydraulic excavator according to the embodiment of the present invention. In addition, the same code | symbol is attached | subjected to the same part as the previous figure, and description is abbreviate | omitted (the following figure is also the same). The drive control system shown in this figure includes operating devices 4A and 4B, control valves (spool type directional switching valves) 5A, 5B and 5C, pressure sensors 17 and 18 for converting hydraulic signals into electric signals, and inverter devices ( It includes a power conversion device 13, a chopper 14, a battery (power storage device) 15, and an inverter device (power conversion device) 12. As a control device, a vehicle body controller (MCU) 11, a battery controller (BCU) 22, and an engine A controller (ECU) 21 is provided.

  The vehicle body controller (MCU) 11, the battery controller (BCU) 22, and the engine controller (ECU) 21 each have a hardware configuration, an arithmetic processing unit (for example, CPU) for executing various control programs, and the control program And a storage device (for example, ROM, RAM) for storing various data (not shown). Here, the controllers 11, 21, and 22 are described as being configured by different hardware, but the arithmetic processing executed by the controllers 11, 22, and 21 may be executed by common hardware.

  The operating devices 4A and 4B are used for controlling the hydraulic cylinder 3a, the hydraulic cylinder 3b, the hydraulic cylinder 3c, and the swing motor 16 by reducing the hydraulic oil supplied from the pilot pump 51 connected to the engine 7 to a secondary pressure. Generates a hydraulic signal (pilot pressure).

  The operating device 4A is connected via a pilot pipe to a pressure receiving portion of a control valve 5A that controls the driving of the hydraulic cylinder 3a and a pressure receiving portion of a control valve 5B that controls the driving of the hydraulic cylinder 3b. A hydraulic signal is output to the pressure receiving portion of each control valve 5A, 5B according to the direction. The positions of the control valves 5A and 5B are switched according to the hydraulic signal input from the operating device 4A, and the hydraulic cylinders 3a and 5B are controlled by controlling the flow of the pressure oil discharged from the hydraulic pump 6 according to the switching position. The driving of 3b is controlled.

  The operating device 4B is connected to the pressure receiving portion of the control valve 5C that controls the driving of the hydraulic cylinder 3c via a pilot pipe line, and outputs a hydraulic signal to the pressure receiving portion of the control valve 5C according to the tilting direction of the operating lever. To do. The position of the control valve 5C is switched according to the hydraulic signal input from the operating device 4B, and the hydraulic cylinder 3c is driven by controlling the flow of pressure oil discharged from the hydraulic pump 6 according to the switching position. Control.

  The operating device 4B is connected to the pilot pipeline 19 and the pilot pipeline 20. The pilot line 19 passes a hydraulic signal (pressure oil) that drives the turning motor 16 so that the upper turning body 1d turns left, and the pilot line 20 causes the upper turning body 1d to turn right. The hydraulic signal (pressure oil) for driving the turning motor 16 passes through. A pressure sensor 17 is attached to the pilot line 19, and a pressure sensor 18 is attached to the pilot line 20. The pressure sensors 17 and 18 function as signal conversion means for detecting the pressure of the hydraulic signal output from the operating device 4B and converting it into an electrical signal corresponding to the pressure. The converted electrical signal is sent to the vehicle body controller 11. It is configured to allow output. The electric signal output from the pressure sensors 17 and 18 to the vehicle body controller 11 is used as an operation signal for controlling the driving of the turning motor 16 (electric actuator) via the inverter device 13.

  The pressure receiving portions of the control valves 5E and 5F are connected to a travel operation device (not shown) installed in the cab via a pilot line. The control valves 5E and 5F are switched in position in accordance with a hydraulic signal input from the travel operation device, and the travel motor 3e is controlled by controlling the flow of pressure oil discharged from the hydraulic pump 6 in accordance with the switching position. , 3f are controlled.

  The battery controller (BCU) 22 has a function of calculating a remaining capacity (SOC: State of Charge) of the battery 15 and a function of calculating a degree of deterioration (SOH: State of Health) of the battery 15, and the calculation result is obtained. Output to the vehicle body controller 11. In addition, SOC can be defined as (remaining capacity [Ah] / full charge capacity [Ah]) × 100, and SOH can be defined as (full charge capacity during degradation [Ah] / initial full charge capacity [AH]) × 100, It can be estimated by various known calculation methods.

  As a known calculation method of the SOC, there is a method of measuring the charge / discharge current of the battery 15 and integrating the current value. As a method for measuring the charge / discharge current, the current is directly measured by a current sensor (not shown) attached to the input / output portion of the battery 15 or indirectly from the rotational speed and torque of the motor connected to the battery 15. There is something to measure. Further, as a known calculation method of SOH, for example, there is one described in Japanese Patent Laid-Open No. 2008-256673, but detailed description thereof is omitted here. The calculated SOC and SOH may be appropriately displayed on the monitor 23 by the battery controller 22. Further, when the battery 15 is largely deteriorated (when the value of SOH is small), it is preferable to notify the operator that there is a possibility that sufficient power required for the work cannot be secured.

  The vehicle body controller (MCU) 11 has a role of controlling the driving of the turning motor 16 via the inverter device 13 based on electric signals input from the pressure sensors 17 and 18. Specifically, when an electrical signal is input from the pressure sensor 17, the upper swing body 1 d is turned left at a speed corresponding to the electrical signal, and when an electrical signal is input from the pressure sensor 18, it corresponds to the electrical signal. The upper swing body 1d is turned right at a speed. The vehicle body controller 11 also performs power regeneration control for recovering electrical energy from the turning motor 16 during the turning braking of the upper turning body 1d. The battery 15 is also charged with regenerative power generated during the power regeneration control or surplus power generated by the generator motor (power converter) 10 (for example, when the load of the hydraulic pump 6 is light). Do.

  The engine controller (ECU) 21 controls the engine 7 according to a command from an engine speed input device (for example, an engine control dial (not shown)) in which the operator inputs the target speed of the engine 7. This is the part that controls the fuel injection amount and the engine speed so that the engine rotates.

  A generator motor 10 is connected to an output shaft of the engine (prime mover) 7, and a hydraulic pump 6 and a pilot pump 41 are connected to the output shaft of the generator motor 10.

  The generator motor 10 is a hydraulic pump that uses electric energy supplied from the battery 15 in addition to a function as a generator that converts the power of the engine 7 into electric energy and outputs the electric energy to the inverter devices 12 and 13. 6 (engine 7) has a function as an electric motor for assisting driving.

  The hydraulic pump 6 is a main pump that supplies pressure oil to the hydraulic cylinders 3a, 3b, 3c and the hydraulic motors 3e, 3f, which are hydraulic actuators. The pilot pump 41 passes through the operation devices 4A, 4B and the travel operation device. Then, pressure oil output as an operation signal is supplied to the control valves 5A, 5B, 5C, 5D, 5E, and 5F. A relief valve 8 is installed in the hydraulic line connected to the hydraulic pump 6, and the relief valve 8 allows pressure oil to escape to the tank 9 when the pressure in the line rises excessively.

  The inverter device 12 controls the driving of the generator motor 10 based on the output from the vehicle controller 11, and when the generator motor 10 is operated as a motor, the electric energy of the battery 15 is converted into AC power to generate power. This is supplied to the electric motor 10 to assist the hydraulic pump 6.

  The inverter device 13 performs drive control of the turning motor 16 based on the output from the vehicle body controller 11. The inverter device 13 converts electric power output from at least one of the generator motor 10 and the power storage device 15 into AC power and converts the electric motor 16. To supply.

  The chopper 14 controls the voltage of the DC power line to which the inverter devices 12 and 13 are connected. The battery (power storage device) 15 supplies electric power to the inverter devices 12 and 13 via the chopper 14, stores electrical energy generated by the generator motor 10, and electrical energy regenerated from the generator 25 and the electric motor 16. To do. As the power storage device other than the battery 15, for example, a capacitor can be used, and both the capacitor and the battery may be used. Note that, when a battery is used as the power storage device, a larger amount of electric power can be stored compared to a capacitor, so that improvement in work efficiency and energy saving effect can be expected.

  The mode selection switch (work mode selector) 29 is for the operator to select one of a plurality of work modes determined according to the work content of the hydraulic excavator (work machine). The work modes include, for example, a heavy work mode (power mode) emphasizing work amount, a light work mode (light mode) emphasizing operating time, and an economy mode emphasizing efficiency positioned between the two. The maximum discharge amount is set for each work mode. Among the three modes, the maximum value of the discharge amount is set to be the largest in the heavy work mode, and the maximum value of the discharge amount is set to be small in the order of the economy mode and the light work mode. For example, excavation work and loading work are recommended as the work recommended to select the heavy work mode, and the leveling work is recommended as the work recommended to select the light work mode. Here, description will be made on the assumption that the above three modes (heavy work mode, economy mode, and light work mode) exist.

The work mode (the maximum discharge amount per hour of the power storage device) input via the mode selection switch 29 is output to the vehicle body controller 11. The mode selection switch 29 may be any switch as long as the work mode can be selected. For example, a dial type switch shown in FIG. 2 or a touch panel type using a monitor (display device) 23 may be used. Things may be used. In the above example, three work modes can be selected. Needless to say, the work mode that can be selected (the maximum value of the discharge amount per hour of the power storage device) is not limited to this. The work mode (the maximum value of the amount of discharge per hour of the power storage device) is input to the vehicle body controller 11 via the selection switch 29. However, each work mode is associated with the scheduled operation time of the hydraulic excavator, and the scheduled operation time. Alternatively, another input device that can input the work mode indirectly by inputting any of the above may be provided instead. In this case, the work mode is indirectly determined by the scheduled operation time selected by the other input device, and the vehicle body controller 11 executes a target remaining capacity calculation process to be described later based on the work mode. .

  Here, other functions of the vehicle body controller 11 will be described. FIG. 3 is a functional block diagram of the vehicle body controller 11 according to the embodiment of the present invention. As shown in this figure, the vehicle body controller 11 executes various control programs, thereby operating time calculation unit 61, required power calculation unit 62, command value calculation unit 63, command value calculation unit 64, and maximum value storage unit 65. May function as.

  The operation time calculation unit 61 calculates the estimated operation time of the hydraulic excavator based on the maximum value of discharge power per hour of the battery 15 and the remaining capacity of the battery 15 according to the work mode input via the mode selection switch 29. This part has the function of The operating time calculation unit 61 receives the SOC and SOH output from the battery controller 22 and the work mode output from the mode selection switch 29, and receives the SOC and SOH and the work mode (discharge of the battery 15 per hour). The scheduled operation time is calculated based on the maximum value of power.

  In the maximum value storage unit 65 (for example, ROM, RAM), the maximum value Wk (k = 1, 2,...) Of discharge power per hour of the battery 15 related to each work mode selectable by the mode selection switch 29 is stored. It is remembered. In the present embodiment, W1 (k = 1) which is the maximum value of the discharge power in the heavy work mode, W2 (k = 2) which is the value in the economy mode, and W3 (which is the value in the light work mode) k = 3) is stored. The maximum value Wk stored in the maximum value storage unit 65 is appropriately read according to the request of each unit (for example, the command value calculation units 63 and 64 and the operating time tube calculation unit 61).

  As a calculation method of the scheduled operation time, when SOC is input from the BCU 22, how much the maximum discharge power Wk related to the work mode selected via the mode selection switch 29 is discharged continuously. There is a calculation based on whether or not the discharge can be performed for a certain period of time. That is, this is a method of dividing the amount of power of the battery 15 estimated from the SOC (and SOH) by the maximum value Wk of the discharge power according to the work mode.

  FIG. 9 is a diagram illustrating an example of a change in the target remaining capacity of the battery 15 over time and an expected operation time. Here, the target remaining capacity (final target remaining capacity (see FIG. 9)) of the battery 15 when the scheduled operation time T [h] has elapsed is set to a desired value (the final target remaining capacity can be arbitrarily changed). The remaining capacity of the battery 15 is determined so as to monotonously decrease from the current value (actual remaining capacity calculated from the SOC and SOH from the BCU 22) to the final target remaining capacity at a rate of the maximum value Wk. Yes.

  The scheduled operation time calculated by the operation time calculation unit 61 is appropriately output to the monitor (display device) 23. As a result, the scheduled operating time calculated by the operating time tube calculation unit 61 is displayed on the monitor 23.

  By the way, since the full charge capacity of the battery 15 decreases from the initial state as the deterioration progresses, the actual remaining capacity of the battery 15 differs if the SOH is different even if the SOC is the same. That is, when the SOC is the same value, the actual remaining battery capacity is smaller when the SOH is smaller (the deterioration is progressing). FIG. 10 is a diagram comparing the actual remaining battery capacity when the SOC is the same and the battery 15 is not deteriorated (SOH = 100) and when the deterioration has progressed (SOH = 60). As shown in this figure, when the battery 15 is further deteriorated, the actual remaining capacity is reduced even if the same SOC is indicated. Therefore, when the operation time calculation unit 61 calculates the scheduled operation time as described above, the actual remaining capacity is estimated in consideration of the value of SOH (that is, the smaller the SOH, the smaller the actual remaining capacity). ), It is preferable to determine the scheduled operation time of the hydraulic excavator based on the estimated remaining capacity from the viewpoint of accurately managing the remaining capacity. Here, although the case where the remaining capacity is corrected by the operating time calculation unit 61 has been described, the correction is executed by using the SOH in the battery controller 22 to estimate the actual remaining capacity of the battery 15, You may comprise so that the said estimated remaining capacity may be output to the operation time calculating part 61. FIG.

  The required power calculation unit 62 has a function of calculating the required power Wd of the turning motor 16 for each control cycle based on the operation amount of the controller device 4B. Outputs from the pressure sensors 17 and 18 are input to the required power calculation unit 62 shown in FIG. In the present embodiment, the pressure sensors 17 and 18 function as operation amount detection means of the operation device 4B, and the required power calculation unit 62 calculates the operation amount of the operation device 4B from the output values of the pressure sensors 17 and 18. The required power Wd of the turning motor 16 is calculated in proportion to the magnitude of the operation amount. The required power Wd calculated by the required power calculator 62 is output to the command value calculator 64.

  In the present embodiment, the pilot pressure (hydraulic operation signal) output from the operation device 4B is converted into an electrical signal by the pressure sensors 17 and 18, and the operation amount of the operation device 4B is detected. A configuration in which an electric operation signal corresponding to the operation amount of the device 4B is directly output to the vehicle body controller 11 may be employed. In this case, a position sensor (for example, a rotary encoder) that detects the rotational displacement of the operation lever in the operation device 4B can be used. Further, in the present embodiment, the operation device 4B includes the two hydraulic sensors 17 and 18. However, for example, sensors having different detection methods such as a combination of the hydraulic sensor and the position sensor may be used in combination. In this way, the reliability of the system can be improved.

  The command value calculation unit (first command value calculation unit) 64 is a part that calculates a command value output to the inverter device 13 for controlling the turning motor (electric actuator) 16. The command value calculation unit 64 functions as an electric motor control unit for controlling the turning motor 16 together with the inverter device 13. The command value calculation unit 64 calculates a command value for the inverter device 13 based on the deviation between the maximum value Wk of the discharge power per hour of the battery 15 for each work mode and the required power Wd of the swing motor 16.

  FIG. 4 is a flowchart of the control process of the turning motor 16 executed by the vehicle body controller 11 according to the embodiment of the present invention. When the operator operates the operating device 4B to instruct the swing of the upper swing body 1d of the excavator, the detection value of one of the two pressure sensors 17 and 18 increases. The vehicle body controller 11 inputs the outputs of the pressure sensors 17 and 18 in the required power calculation unit 62 (S701), and calculates the required power Wd of the turning motor 16 based on this (S702). The required power Wd calculated here is output to the command value calculation unit 64.

  The vehicle body controller 11 reads the maximum value Wk of the discharge power corresponding to the work mode from the maximum value storage unit 65 based on the work mode input from the mode selection switch 29 in the command value calculation unit 64. For example, when the heavy work mode is selected, the maximum value W1 is read (S703). In FIG. 4, S703 is executed after S702, but may be executed simultaneously with or before S702.

  When S703 ends, the vehicle body controller 11 executes a process of comparing the maximum value Wk and the required power Wd in the command value calculation unit 64 (S704). As a method of comparing the magnitudes of the two, there is a method in which a calculation for subtracting the required power Wd from the maximum value Wk is executed and the sign of the calculation result (deviation between the maximum value Wk and the required power Wd) is determined. That is, if the sign is positive, the maximum value Wk is large, and if the sign is negative, the required power Wd is large.

  When it is determined in S704 that Wk is large, the command value calculation unit 64 outputs the required power Wd to the inverter device 13 (S705). As a result, the turning motor 16 outputs the power desired by the operator (product of torque and rotational speed).

  On the other hand, if it is determined in S704 that the required power Wd is large, Wk is output to the inverter device 13 (S706). Thereby, the turning motor 16 outputs a power smaller than a value desired by the operator, and the discharge power per hour of the battery 15 is always controlled to the maximum value Wk or less. Since the power (output) of the turning motor 16 is represented by the product of the torque and the rotational speed, at least one of the torque and the rotational speed is limited in this case.

  The command value calculation unit (second command value calculation unit) 63 is a part that calculates a command value to be output to the inverter device 12 in order to control the generator motor 10. The command value calculation unit 63 functions as a generator motor control unit for controlling the generator motor 10 together with the inverter device 12.

  The command value calculation unit 63 may calculate a command value for the inverter device 12 based on a deviation between the maximum value Wk of the discharge power per hour of the battery 15 for each work mode and the required power Wd of the swing motor 16. This case will be described with reference to FIG.

  FIG. 5 is a flowchart of the control process of the generator motor 10 executed by the vehicle body controller 11 according to the embodiment of the present invention. When the processing shown in the figure is started, the command value calculation unit 63 (vehicle body controller 11) is selected by the mode selection switch 29 while inputting the required power Wd calculated by the required power calculation unit 62 (S801). The maximum value Wk of the discharge power corresponding to the work mode is input from the maximum value storage unit 65 (S802). In FIG. 5, S802 is executed after S801, but may be executed simultaneously with or before S801.

  When S802 ends, the command value calculation unit 63 executes a process of comparing the maximum value Wk with the required power Wd. Here, as a method of comparing the magnitudes of the two, a calculation for subtracting the required power Wd from the maximum value Wk is executed (S803), and the sign of the calculation result (deviation between the maximum value Wk and the required power Wd) is determined. (S804). That is, if the sign is positive, the maximum value Wk is large, and if the sign is negative, the required power Wd is large.

  In S804, when the sign of the deviation between the maximum value Wk and the required power Wd is positive, the required power Wd falls below the maximum value Wk, so the command value calculation unit 63 outputs an assist command to the inverter device 12. (S805). Thereby, the generator motor 10 receives the supply of electric power corresponding to the difference between the maximum value Wk and the required electric power Wd from the battery 15 and performs the assist drive of the engine 7. Thereby, the fuel consumption of the engine 7 can be suppressed.

  On the other hand, in S704, when the sign of the deviation between the maximum value Wk and the required power Wd is negative, the required power Wd exceeds the maximum value Wk. Therefore, the command value calculation unit 63 sends a power generation command to the inverter device 12. It outputs (S806). Thereby, the generator motor 10 generates power corresponding to the difference between the maximum value Wk and the required power Wd, and supplies the power to the swing motor 16 to support the swing drive of the upper swing body 1d. .

  Here, the case where both the power generation by the generator motor 10 and the engine assist are performed based on the sign of the value obtained by subtracting the required power Wd from the maximum value of the discharge power Wk has been described, but only one of the power generation and the engine assist is performed. It may be configured so that the other is not performed.

The operation and effect of the next embodiment will be described with reference to FIGS.
FIG. 6 is a diagram schematically showing a change in the required power Wd with respect to the maximum value Wk (k = 1, 3) of the discharge power during operation of the hydraulic excavator. 6 to 8, it is assumed that the “light work mode” is selected by the mode selection switch 29, and the maximum value of the discharge power is set to W3. In FIG. 6, the required power Wd exceeds the maximum value W3 in the interval from time 0 to t1 and in the interval from time t2 to T.

  FIG. 7 is a diagram schematically showing a change in power actually supplied to the turning motor 16 when the demand power Wd changes as shown in FIG. In the example of this figure, it is assumed that only the swing motor 16 shown in FIG. 4 is controlled, and the power generation motivator 10 shown in FIG. 5 is not controlled. Therefore, as shown in FIG. 7, the processing of S704 and 706 in FIG. 4 is executed in the section from time 0 to t1 and the section from time t2 to T2 when the required power Wd exceeds the maximum value W3 and supplied to the turning motor 16. The power to be used is limited to the maximum value W3.

  As described above, when only the control shown in FIG. 4 is performed, the maximum value of the power discharged from the battery 15 is set for each work mode, so the discharge power of the work mode selected by the mode selection switch 9 is set. The estimated operation time can be calculated on the basis of the maximum value (for example, assuming that the maximum value is continuously discharged from the SOC of the current battery 15, the shortest operation time in the work mode can be predicted. .) Then, since the calculated scheduled operation time is notified to the operator via the monitor 23, it is possible to prevent power shortage during work against the operator's intention. If the scheduled operation time is shorter than the operator's desired time, the scheduled operation time can be extended by changing to a work mode in which the maximum value of the discharge power is relatively small. It is also possible to adjust the operating time. Therefore, according to this Embodiment, it can suppress that the remaining capacity of the battery 15 is lose | eliminated within the scheduled operation time, and the working efficiency of a hydraulic shovel falls more than necessary.

  FIG. 11 is a diagram illustrating an example of the scheduled operation time when the heavy work mode and the light work mode are selected. In this figure, a straight line denoted by reference numeral 91 is a time variation of the remaining capacity of the battery 15 in the light work mode, and a straight line denoted by reference numeral 92 is a time variation of the remaining capacity in the heavy work mode. . In FIG. 11, since the maximum value W1 of the discharge power in the heavy work mode is larger than the value (W3) in the light work mode, the scheduled operation time T2 becomes shorter than the light work mode time T1. Thereby, when the heavy work mode is selected via the input device 29, the battery output per unit time is increased, so that work efficiency can be prioritized over work time. On the other hand, when the light work mode is selected, since the battery output per unit time can be reduced, the work time can be prioritized over the work efficiency. Therefore, if the hydraulic excavator is configured in this way, the capacity of the battery 15 can be used efficiently according to the load of the work content desired by the operator.

  FIG. 8 is a diagram schematically showing a change in the power actually supplied to the turning motor 16 when the demand power Wd changes as shown in FIG. In the example of this figure, it is assumed that the control of the turning motor 16 shown in FIG. 4 and the control of the power generation motive 10 shown in FIG. 5 are performed. Therefore, as shown in FIG. 8, the processing of S804 and 806 in FIG. 5 is executed in the section from time 0 to t1 when the required power Wd exceeds the maximum value W3 and the section from time t2 to T, and the inverter device 12 generates power. A command is output. Further, in the section from time t1 to t2 when the required power Wd is lower than the maximum value W3, the processing of S804 and 805 in FIG. 5 is executed, and an assist command is output to the inverter device 12.

  Thus, even when the control shown in FIG. 5 as well as FIG. 4 is performed, the remaining capacity of the battery 15 is eliminated within the scheduled operation time, and the working efficiency of the hydraulic excavator is prevented from being lowered more than necessary. it can. In particular, in the case shown in FIG. 8, even if the required power Wd of the swing motor 16 fluctuates, the fluctuation is absorbed by the power generation or driving of the generator motor 10. Therefore, since the output of the battery 15 only needs to be kept substantially constant, the remaining battery capacity can be controlled very easily.

  In the above description, the case where there is one electric actuator driven by the electric power of the battery 15 has been described, but the present invention can also be applied to the case where a plurality of electric actuators are driven. In this case, a total value (total required power) of the required power of each electric actuator is calculated by the required power calculation unit 62, and the total required power is compared with the maximum value Wk (k = 1, 2,...). good. That is, when the maximum value Wk exceeds, the power corresponding to the difference is supplied to the plurality of electric actuators for which power is insufficient, and when the total required power is lower than the maximum value Wk, the power corresponding to the difference is generated. What is necessary is just to make it assist the engine 7 by supplying to the electric motor 10.

  In the above description, the case where the electric actuator driven by the electric power of the battery 15 is the swing motor (electric motor) 16 has been described. However, the case where other electric actuators (for example, an electric linear actuator and an electric pump) are also provided. The present invention is applicable. Furthermore, in the above description, a hydraulic excavator has been described as an example of a hybrid work machine. However, it is needless to say that the present invention can also be applied to other hybrid work machines including an electric actuator driven by electric power of a power storage device. No.

Wk Maximum discharge power per hour Wd Required power T Expected operation time 1d Upper swing body 4A, 4B Operating device 7 Engine 10 Generator motor 11 Car body controller 15 Battery 16 Turning motor (electric actuator)
17 Pressure Sensor 18 Pressure Sensor 22 Battery Controller 29 Mode Selection Switch 61 Operating Time Calculation Unit 62 Required Power Calculation Unit 63 Command Value Calculation Unit 64 Command Value Calculation Unit 65 Maximum Value Storage Unit

Claims (5)

A power storage device;
An electric actuator driven by power supply from the power storage device;
An input device for setting a maximum value of discharge power per hour of the power storage device;
A control device that controls the discharge power per hour of the power storage device to be equal to or less than a set value by the input device, and calculates a scheduled operation time of the work machine based on the remaining capacity of the power storage device and the set value;
A work machine comprising: a display device configured to display a scheduled operation time of the work machine calculated by the control device. The work machine according to claim 1,
A generator motor driven by the engine;
When the required electric power of the electric actuator exceeds a set value by the input device, the control device generates electric power corresponding to a difference between the required electric power and the set value by the generator motor and supplies the electric power to the electric actuator. A working machine characterized by In the work machine according to claim 1 or 2,
The control device corrects a remaining capacity of the power storage device according to a degree of deterioration of the power storage device, and calculates the scheduled operation time based on the corrected remaining capacity. The work machine according to any one of claims 1 to 3,
The input device is a mode selection switch for selecting one of a plurality of work modes determined according to the work content of the work machine,
A working machine, wherein a maximum value of discharge power per hour of the power storage device is set according to a work mode selected by the switch. The work machine according to claim 2,
When the required power of the electric actuator falls below a set value by the input device, the control device supplies power corresponding to a difference between the required power and the set value from the power storage device to the generator motor. A work machine characterized by assist driving.

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