JP2009261227A - Hybrid working machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hybrid working machine capable of cooling a capacitor efficiently by making effective use of the capacitor power. <P>SOLUTION: By driving a cooling device 60 using a power charged on a capacitor 19 after stoppage of an engine 11, the capacitor 19 can be cooled while allowing the SOC of the capacitor 19 to be decreased to a given value (80% in this form). Accordingly, the capacitor 19 decreases its SOC due to discharging and drives the cooling device 60 using its discharging power, being cooled by the cooling device 60. As a result, a hybrid working machine can be provided that makes effective use of the power and extends a lifetime of the capacitor 19. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a hybrid work machine including a motor generator for assisting an engine.

  Conventionally, a hybrid work machine including a motor generator for assisting an engine includes a capacitor for supplying electric power to the motor generator and charging regenerative power. Since such a capacitor is used in an environment where charge and discharge are repeatedly performed, various devices have been devised for extending the life.

  For example, considering that the capacitor deteriorates if the voltage value of the capacitor increases too much, a discharge set value is provided for the capacitor voltage value, and the charge voltage of the capacitor exceeds the discharge set value at the end of the operation of the hybrid work machine In this case, it has been proposed to extend the life of the capacitor by causing the discharge so that the voltage value of the capacitor is equal to or lower than the discharge set value. The discharged power was stored in the auxiliary battery (for example, see Patent Document 1).

JP 2005-218285 A

  In general, when a capacitor continues to be used in a high temperature environment, the deterioration is accelerated.

  In the hybrid work machine, the capacitor is used in an environment where charging / discharging is repeatedly performed. Therefore, the amount of heat generated by the internal resistance accompanying charging / discharging becomes a considerable amount, and cooling is necessary. Further, when charging / discharging, it is necessary to manage the capacitor voltage in order to avoid overcharging. In particular, a capacitor that has become hot during work maintains a high temperature state even after the work machine is stopped, leading to early deterioration of the capacitor.

  However, in the conventional hybrid type work machine, the electric power discharged in order to make the voltage value of the capacitor below the discharge set value is transferred from the capacitor to the auxiliary battery, and loss occurs as the electric power moves. The effective use of was not realized. In addition, effective use of electric power has not been performed in cooling for protecting the capacitor.

  Therefore, an object of the present invention is to provide a hybrid work machine that can efficiently cool the capacitor by effectively using the power of the capacitor.

  The hybrid work machine of one aspect of the present invention is a hybrid work machine including a motor generator for assisting an engine, and a capacitor that supplies electric power to the motor generator or charges regenerative power. A cooling device that cools the capacitor and a drive control unit that performs drive control of the cooling device, and the drive control unit drives the cooling device with electric power supplied from the capacitor after the engine is stopped.

  Further, a voltage detection unit that detects a voltage value of the capacitor may be further included, and the drive control unit may perform drive control of the cooling device based on the voltage value of the capacitor detected by the voltage detection unit.

  In this case, the drive control unit may drive the cooling device until the voltage value of the capacitor detected by the voltage detection unit falls to a predetermined voltage value.

  Further, a temperature detection unit that detects a temperature of the capacitor may be further included, and the drive control unit may perform drive control of the cooling device based on a temperature detected by the temperature detection unit.

  In this case, the drive control unit may drive the cooling device until the temperature of the capacitor becomes a predetermined temperature or lower.

  In addition, a secondary battery is connected to the cooling device, and the drive control unit is supplied from the capacitor when the voltage value of the capacitor detected by the voltage detection unit is lower than a predetermined voltage value. You may drive the said cooling device with the electric power supplied from the said secondary battery instead of electric power.

  In addition, a timer for measuring the driving time of the cooling device may be further included, and the driving control unit may stop driving the cooling device when a driving time measured by the timer has passed a predetermined time.

  In addition, a voltage detection unit that detects the voltage value of the capacitor, a temperature detection unit that detects the temperature of the capacitor, and a timer that measures the drive time of the cooling device, the drive control unit, An appropriate driving time of the cooling device is set based on the voltage value of the capacitor detected by the voltage detecting unit and the temperature of the capacitor detected by the temperature detecting unit, and the driving time measured by the timer is the appropriate driving time. After elapses, the driving of the cooling device may be stopped.

  According to the present invention, it is possible to provide a specific effect that it is possible to provide a hybrid work machine that can efficiently cool the capacitor by effectively using the power of the capacitor.

1 is a side view illustrating a hybrid type construction machine according to a first embodiment. 1 is a block diagram illustrating a configuration of a hybrid construction machine according to a first embodiment. It is a figure which shows the process sequence of the drive control of the cooling device 60 performed by the controller. FIG. 5 is a block diagram illustrating a configuration of a hybrid construction machine according to a second embodiment. It is a figure which shows the process sequence of the drive control of the cooling device 60 performed by the controller. It is a figure which shows the process sequence of the drive control of the cooling device 60 performed by the controller 70 of the hybrid type construction machine of Embodiment 3. FIG. It is a figure which shows the process sequence of the drive control of the cooling device 60 performed by the controller 70 of the hybrid type construction machine of Embodiment 4. FIG. It is a figure which shows the structural example of the time table used in order to set cooling device drive time. It is a figure which shows the structural example (general expression) of the time table used in order to set cooling device drive time.

  Hereinafter, an embodiment of a hybrid type construction machine will be described as an embodiment to which the hybrid type working machine of the present invention is applied.

“Embodiment 1”
FIG. 1 is a side view showing the hybrid construction machine of the first embodiment.

  An upper swing body 3 is mounted on the lower traveling body 1 of this hybrid construction machine via a swing mechanism 2. In addition to the boom 4, the arm 5, and the bucket 6, and the boom cylinder 7, the arm cylinder 8, and the bucket cylinder 9 for hydraulically driving them, the upper swing body 3 is equipped with a cabin 10 and a power source. Is done.

"overall structure"
FIG. 2 is a block diagram illustrating the configuration of the hybrid construction machine according to the first embodiment. In FIG. 2, the mechanical power system is indicated by a double line, the high-pressure hydraulic line is indicated by a solid line, the pilot line is indicated by a broken line, and the electric drive / control system is indicated by a one-dot chain line.

  An engine 11 as a mechanical drive unit and a motor generator 12 as an assist drive unit are both connected to an input shaft of a speed reducer 13 as a booster. A main pump 14 and a pilot pump 15 are connected to the output shaft of the speed reducer 13. A control valve 17 is connected to the main pump 14 via a high pressure hydraulic line 16.

  The control valve 17 is a control device that controls the hydraulic system in the construction machine according to the first embodiment. The control valve 17 includes hydraulic motors 1A (for right) and 1B (for left) for the lower traveling body 1, The boom cylinder 7, the arm cylinder 8, and the bucket cylinder 9 are connected via a high pressure hydraulic line.

  The motor generator 12 is connected to a capacitor 19 as a battery via an inverter 18 and a step-up / down converter 30. The inverter 18 and the step-up / down converter 30 are connected by a DC bus 40.

  Further, the turning electric motor 21 is connected to the DC bus 40 via the inverter 20. The DC bus 40 is disposed to transfer power between the capacitor 19, the motor generator 12, and the turning electric motor 21.

  The DC bus 40 is provided with a DC bus voltage detector 41 for detecting a voltage value of the DC bus 40 (hereinafter referred to as a DC bus voltage value). The detected DC bus voltage value is input to the controller 50.

  The capacitor 19 is provided with a capacitor voltage detector 31 for detecting the capacitor voltage value and a capacitor current detector 32 for detecting the capacitor current value. The capacitor voltage value detected by the capacitor voltage detector 31 is input to the controller 50 and a controller 70 described later. The capacitor current value detected by the capacitor current detection unit 32 is input to the controller 50.

  The capacitor 19 is provided with a cooling device 60 for cooling the capacitor 19. The cooling device 60 is a cooling electric fan attached to the casing of the capacitor 19, and drive control is performed by a controller 70 described later.

  A battery 90 is connected to the capacitor 19 and the controller 70 via a switch 80. The battery 90 is a power source for supplying electric power to work lights and electrical components of the hybrid work machine, and is charged with electric power generated by the generator 100 driven by the engine 11.

  A resolver 22, a mechanical brake 23, and a turning speed reducer 24 are connected to the rotating shaft 21 </ b> A of the turning electric motor 21. An operation device 26 is connected to the pilot pump 15 via a pilot line 25.

  A control valve 17 and a pressure sensor 29 as a lever operation detection unit are connected to the operating device 26 via hydraulic lines 27 and 28, respectively. The pressure sensor 29 is connected to a controller 50 that performs drive control of the electric system of the construction machine according to the first embodiment.

  The construction machine according to the first embodiment is a hybrid construction machine that uses the engine 11, the motor generator 12, and the turning electric motor 21 as power sources. These power sources are mounted on the upper swing body 3 shown in FIG. Hereinafter, each part will be described.

"Configuration of each part"
The engine 11 is an internal combustion engine composed of, for example, a diesel engine, and its output shaft is connected to one input shaft of the speed reducer 13. The engine 11 is always operated during the operation of the construction machine.

  The motor generator 12 may be an electric motor capable of both electric (assist) operation and power generation operation. Here, a motor generator that is AC driven by an inverter 18 is shown as the motor generator 12. The motor generator 12 can be constituted by, for example, an IPM (Interior Permanent Magnetic) motor in which a magnet is embedded in a rotor. The rotating shaft of the motor generator 12 is connected to the other input shaft of the speed reducer 13.

  The speed reducer 13 has two input shafts and one output shaft. A drive shaft of the engine 11 and a drive shaft of the motor generator 12 are connected to each of the two input shafts. Further, the drive shaft of the main pump 14 is connected to the output shaft. When the load on the engine 11 is large, the motor generator 12 performs an electric driving (assist) operation, and the driving force of the motor generator 12 is transmitted to the main pump 14 via the output shaft of the speed reducer 13. Thereby, driving of the engine 11 is assisted. On the other hand, when the load of the engine 11 is small, the driving force of the engine 11 is transmitted to the motor generator 12 through the speed reducer 13, so that the motor generator 12 generates power by the power generation operation. Switching between the power running operation and the power generation operation of the motor generator 12 is performed by the controller 50 according to the load of the engine 11 and the like.

  The main pump 14 is a pump that generates hydraulic pressure to be supplied to the control valve 17. This hydraulic pressure is supplied to drive each of the hydraulic motors 1 </ b> A and 1 </ b> B, the boom cylinder 7, the arm cylinder 8, and the bucket cylinder 9 via the control valve 17.

  The pilot pump 15 is a pump that generates a pilot pressure necessary for the hydraulic operation system. The configuration of this hydraulic operation system will be described later.

  The control valve 17 inputs the hydraulic pressure supplied to each of the hydraulic motors 1A, 1B, the boom cylinder 7, the arm cylinder 8 and the bucket cylinder 9 for the lower traveling body 1 connected via a high-pressure hydraulic line. It is a hydraulic control device which controls these hydraulically by controlling according to the above.

  The inverter 18 is provided between the motor generator 12 and the buck-boost converter 30 as described above, and controls the operation of the motor generator 12 based on a command from the controller 50. As a result, when the inverter 18 is electrically driving the motor generator 12, necessary power is supplied from the capacitor 19 and the step-up / down converter 30 to the motor generator 12 via the DC bus 40. Further, when the regeneration of the motor generator 12 is being controlled, the capacitor 19 is charged with the electric power generated by the motor generator 12 via the DC bus 40 and the step-up / down converter 30.

  The capacitor 19 is connected to the inverter 18 and the inverter 20 via the buck-boost converter 30. Thereby, when at least one of the electric (assist) operation of the motor generator 12 and the power running operation of the turning electric motor 21 is performed, electric power necessary for the electric (assist) operation or the power running operation is supplied. In addition, when at least one of the power generation operation of the motor generator 12 and the regenerative operation of the turning motor 21 is performed, the electric power generated by the power generation operation or the regenerative operation is stored as electric energy. Is the power source. The capacitor 19 is a collection of many capacitors.

  The charge / discharge control of the capacitor 19 is based on the charge state of the capacitor 19, the operation state of the motor generator 12 (electric (assist) operation or power generation operation), and the operation state (power running operation or regenerative operation) of the turning motor 21. This is performed by the step-up / down converter 30. Switching control between the step-up / step-down operation of the step-up / step-down converter 30 is performed by the capacitor voltage value detected by the capacitor voltage detection unit 31, the capacitor current value detected by the capacitor current detection unit 32, and the DC bus voltage detection unit 41. This is performed by the controller 50 based on the detected DC bus voltage value.

  The inverter 20 is provided between the turning electric motor 21 and the step-up / down converter 30 as described above, and performs operation control on the turning electric motor 21 based on a command from the controller 50. As a result, when the inverter 20 is operating and controlling the power running of the turning electric motor 21, necessary electric power is supplied from the capacitor 19 to the turning electric motor 21 through the step-up / down converter 30. Further, when the turning electric motor 21 is performing a regenerative operation, the electric power generated by the turning electric motor 21 is charged into the capacitor 19 via the step-up / down converter 30. FIG. 2 shows an embodiment including a swing motor (1 unit) and an inverter (1 unit), but by providing a drive unit other than the magnet mechanism and the swing mechanism unit, a plurality of motors and a plurality of inverters are provided. It may be connected to the DC bus 40.

  The buck-boost converter 30 has one side connected to the motor generator 12 and the turning electric motor 21 via the DC bus 40 and the other side connected to the capacitor 19 so that the DC bus voltage value falls within a certain range. Thus, control for switching between step-up and step-down is performed. When the motor generator 12 performs an electric driving (assist) operation, it is necessary to supply electric power to the motor generator 12 via the inverter 18, and thus it is necessary to boost the DC bus voltage value. On the other hand, when the motor generator 12 performs a power generation operation, it is necessary to charge the capacitor 19 via the inverter 18 with the generated power, and thus it is necessary to step down the DC bus voltage value. The same applies to the power running operation and the regenerative operation of the turning electric motor 21. In addition, the operation state of the motor generator 12 is switched according to the load state of the engine 11, and the turning electric motor 21 is changed to the upper turning body 3. Since the driving state is switched in accordance with the turning operation, the motor generator 12 and the turning motor 21 are either in an electric (assist) operation or a power running operation, and the other is in a power generation operation or a regenerative operation. Can occur.

  For this reason, the step-up / step-down converter 30 performs control for switching between the step-up operation and the step-down operation so that the DC bus voltage value falls within a certain range according to the operating state of the motor generator 12 and the turning electric motor 21.

  The capacitor voltage detection unit 31 is a voltage detection unit for detecting the voltage value of the capacitor 19, and is used for detecting the charge state of the capacitor 19. The detected capacitor voltage value is input to the controller 50 and the controller 70 and used for switching control between the step-up / step-down operation of the step-up / step-down converter 30.

  The capacitor current detection unit 32 is a current detection unit for detecting the current value of the capacitor 19. The capacitor current value is detected as a positive value of the current flowing from the capacitor 19 to the buck-boost converter 30. The detected capacitor current value is input to the controller 50 and used for switching control between the step-up / step-down operation of the step-up / step-down converter 30.

  The DC bus 40 is disposed between the two inverters 18 and 20 and the buck-boost converter 30 and is configured to be able to transfer power between the capacitor 19, the motor generator 12, and the turning motor 21. ing.

  The DC bus voltage detection unit 41 is a voltage detection unit for detecting a DC bus voltage value. The detected DC bus voltage value is input to the controller 50, and is used for switching control between the step-up operation and the step-down operation for keeping the DC bus voltage value within a certain range.

  The cooling device 60 is a cooling electric fan attached to the casing of the capacitor 19, and is driven by electric power supplied from the capacitor 19 to cool the capacitor 19.

  The cooling device 60 is driven and controlled by the controller 70, and power is supplied from the capacitor 19 through a switch 72 and a DC-DC converter 73 described later.

  The controller 70 is composed of an arithmetic processing unit including a CPU (Central Processing Unit) 71, a switch 72, a DC-DC converter 73, and an internal memory (not shown), and the CPU 71 stores a drive control program stored in the internal memory. Is a control device that controls the driving of the cooling device 60, and is driven by electric power supplied from the capacitor 19 when the voltage value of the capacitor 19 is equal to or higher than a predetermined voltage value after the engine 11 is stopped. Then, the capacitor 19 is cooled, and the capacitor 19 is discharged until the voltage value becomes equal to or lower than a predetermined voltage value by causing the capacitor 19 to release electric power for driving the cooling device 60.

  The controller 70 incorporates a timer that measures the driving time of the cooling device 60.

  The switch 72 is a switch for supplying the power supplied from the capacitor 19 to the cooling device 60 via the DC-DC converter 73, and the drive control is performed by the CPU 71. The switch 72 is open unless otherwise specified.

  The DC-DC converter 73 is a transformer that converts a voltage (for example, 360 V) supplied from the capacitor 19 via the switch 72 into a driving voltage value (24 V) of the cooling device 60.

  The switch 80 is a switch that is controlled to be opened and closed by the controller 70, and supplies power to the cooling device 60 from the battery 90 when it is necessary to drive the cooling device 60 when the charging rate of the capacitor 19 is insufficient. When closed. For this reason, this switch 80 is open unless otherwise specified.

  The battery 90 is a power source for supplying power to work lights and electrical components of the hybrid work machine, and is charged with power generated by the generator 100 driven by the engine 11.

  The generator 100 is a generator that is driven via a fan belt wound around the rotating shaft 11 </ b> A of the engine 11, and may have any capacity that can generate electric power necessary for charging the battery 90.

  The turning electric motor 21 may be an electric motor capable of both power running operation and regenerative operation, and is provided to drive the turning mechanism 2 of the upper turning body 3. During the power running operation, the rotational force of the rotational driving force of the turning electric motor 21 is amplified by the speed reducer 24, and the upper turning body 3 is subjected to acceleration / deceleration control to perform rotational motion. Further, due to the inertial rotation of the upper swing body 3, the number of rotations is increased by the speed reducer 24 and transmitted to the turning electric motor 21, and regenerative power can be generated. Here, as the electric motor 21 for turning, an electric motor driven by an inverter 20 by a PWM (Pulse Width Modulation) control signal is shown. The turning electric motor 21 can be constituted by, for example, a magnet-embedded IPM motor. Thereby, since a larger induced electromotive force can be generated, the electric power generated by the turning electric motor 21 at the time of regeneration can be increased.

  The resolver 22 is a sensor that detects the rotational position and the rotational angle of the rotating shaft 21A of the turning electric motor 21, and is mechanically connected to the turning electric motor 21 to rotate the rotating shaft 21A before the turning electric motor 21 rotates. The rotation angle and the rotation direction of the rotation shaft 21A are detected by detecting the difference between the position and the rotation position after the left rotation or the right rotation. By detecting the rotation angle of the rotation shaft 21A of the turning electric motor 21, the rotation angle and the rotation direction of the turning mechanism 2 are derived. Further, FIG. 2 shows a form in which the resolver 22 is attached, but an inverter control system that does not have an electric motor rotation sensor may be used.

  The mechanical brake 23 is a braking device that generates a mechanical braking force, and mechanically stops the rotating shaft 21 </ b> A of the turning electric motor 21. This mechanical brake 23 is switched between braking and release by an electromagnetic switch. This switching is performed by the controller 50.

  The turning speed reducer 24 is a speed reducer that reduces the rotational speed of the rotating shaft 21 </ b> A of the turning electric motor 21 and mechanically transmits it to the turning mechanism 2. Thereby, in the power running operation, the rotational force of the turning electric motor 21 can be increased and transmitted to the turning body as a larger rotational force. On the contrary, during the regenerative operation, the number of rotations generated in the revolving structure can be increased, and more rotational motion can be generated in the turning electric motor 21.

  The turning mechanism 2 can turn in a state where the mechanical brake 23 of the turning electric motor 21 is released, whereby the upper turning body 3 is turned leftward or rightward.

  The operating device 26 is an operating device for operating the turning electric motor 21, the lower traveling body 1, the boom 4, the arm 5, and the bucket 6, and is operated by a driver of the hybrid type construction machine.

  The operating device 26 converts the hydraulic pressure (primary hydraulic pressure) supplied through the pilot line 25 into hydraulic pressure (secondary hydraulic pressure) corresponding to the operation amount of the driver and outputs the converted hydraulic pressure. The secondary hydraulic pressure output from the operating device 26 is supplied to the control valve 17 through the hydraulic line 27 and detected by the pressure sensor 29.

  When the operation device 26 is operated, the control valve 17 is driven through the hydraulic line 27, thereby controlling the hydraulic pressure in the hydraulic motors 1 </ b> A and 1 </ b> B, the boom cylinder 7, the arm cylinder 8, and the bucket cylinder 9. The lower traveling body 1, the boom 4, the arm 5, and the bucket 6 are driven.

  The hydraulic line 27 supplies hydraulic pressure necessary for driving the hydraulic motors 1A and 1B, the boom cylinder 7, the arm cylinder 8, and the bucket cylinder to the control valve.

  When the operation for turning the turning mechanism 2 is input to the operating device 26, the pressure sensor 29 as the turning operation detection unit detects the operation amount as a change in the hydraulic pressure in the hydraulic line 28. The pressure sensor 29 outputs an electrical signal indicating the hydraulic pressure in the hydraulic line 28. Thereby, the operation amount for turning the turning mechanism 2 input to the operating device 26 can be accurately grasped. This electric signal is input to the controller 50 and used for driving control of the turning electric motor 21. In the first embodiment, a description will be given of a mode in which a pressure sensor is used as a lever operation detection unit. However, a sensor that reads an operation amount for turning the turning mechanism 2 input to the operating device 26 as an electric signal is used. May be.

  The controller 50 is a control device that performs drive control of the hybrid construction machine according to the first embodiment. The controller 50 includes an arithmetic processing unit including a CPU and an internal memory. The CPU 50 stores a drive control program stored in the internal memory. It is a device realized by executing.

  The controller 50 controls operation of the engine 11, operation control of the motor generator 12 (switching between electric (assist) operation or power generation operation), charge / discharge control of the capacitor 19 by driving control of the buck-boost converter 30, and turning It is a control device for performing drive control of the electric motor 21. In the drive control of the electric motor 21 for turning, the controller 50 converts a signal inputted from the pressure sensor 29 (a signal representing an operation amount for turning the turning mechanism 2 inputted to the operating device 26) into a speed command. This is executed by performing drive control of the turning electric motor 21 using this speed command.

  The controller 50 is a step-up / down converter based on the charging state of the capacitor 19, the operating state of the motor generator 12 (electric (assist) operation or generating operation), and the operating state of the turning motor 21 (power running operation or regenerative operation). Switching control between 30 step-up operations and step-down operations is performed, and thereby charge / discharge control of the capacitor 19 is performed.

  Switching control between the step-up / step-down operation of the step-up / step-down converter 30 is performed by the capacitor voltage value detected by the capacitor voltage detection unit 31, the capacitor current value detected by the capacitor current detection unit 32, and the DC bus voltage detection unit 41. This is performed based on the detected DC bus voltage value.

  The operation control of the engine 11 includes start and stop control of the engine 11 as well as control of the fuel injection amount according to the load state of the engine 11. Signals representing the start and stop of the engine 11 are transmitted to the controller 70.

"Drive control of cooling device 60 by controller 70"
FIG. 3 is a diagram showing a processing procedure of drive control of the cooling device 60 executed by the controller 70.

  When the controller 70 receives a signal indicating that the engine 11 has been stopped from the controller 50, the controller 70 starts the processing shown in FIG. At this time, measurement of elapsed time by the built-in timer is started.

  First, the controller 70 starts driving the cooling device 60 (step S11). Specifically, the CPU 71 of the controller 70 closes the switch 72 and steps down the power (voltage value is about 360V) supplied from the capacitor 19 by the DC-DC converter 73 (to 24V) to the cooling device 60. Supply. Thereby, the electric fan of the cooling device 60 is rotationally driven, and the capacitor 19 is cooled.

  Next, the controller 70 measures the capacitor voltage (step S12). Specifically, the controller 70 receives a signal representing the capacitor voltage value from the capacitor voltage detection unit 31.

  Furthermore, the controller 70 compares the capacitor voltage value with a predetermined threshold value to determine whether or not the capacitor voltage value has become equal to or lower than the predetermined threshold value (step S13). For example, the predetermined threshold is set to 80% in the SOC (State of charge) of the capacitor 19.

  If the capacitor voltage value is less than or equal to the predetermined threshold (YES in step S13), it is determined that the capacitor 19 has been sufficiently discharged, and the controller 70 advances the procedure to step S14.

  The controller 70 stops the cooling device 60 (step S14). This is realized by the CPU 71 opening the switch 72.

  By the way, when it is determined in step S13 that the capacitor voltage value is higher than the predetermined threshold (NO in step S13), the controller 70 advances the procedure to step S15, and the integrated time of the built-in timer has passed the predetermined time. Is determined (step S15).

  When the integrated time of the built-in timer has passed the predetermined time (YES in step S15), the controller 70 determines that the capacitor 19 has been sufficiently discharged and cooled, and advances the procedure to step S14 to cool the cooling device. 60 is stopped. The predetermined time here is, for example, 60 minutes, so that the controller 70 can drive the cooling device 60 even if the capacitor voltage value detected by the capacitor voltage detection unit 31 is abnormal (for example, This is a case where the capacitor voltage value does not decrease despite the fact that the cooling device 60 is not.), The cooling device 60 can be stopped appropriately.

  On the other hand, when it is determined that the integrated time of the built-in timer has not passed the predetermined time (threshold value) (NO in step S15), the controller 70 is insufficient in discharging and cooling the capacitor 19, and the capacitor voltage value. If it is still high, the procedure is returned to step S12, and steps S12, S13, and S15 are repeated.

  Thus, the drive control of the cooling device 60 by the controller 70 is completed.

  In a conventional hybrid construction machine, the electric power discharged to make the voltage value of the capacitor equal to or lower than the discharge set value has not been used for cooling the capacitor. For this reason, coexistence of efficient use of discharged electric power and cooling of the capacitor has not been realized.

  However, according to the hybrid construction machine of the present embodiment, after the engine 11 is stopped, the capacitor 19 is cooled by driving the cooling device 60 using the electric power charged in the capacitor 19, The SOC of the capacitor 19 can be reduced to a predetermined value (80% in this embodiment).

  As a result, the SOC of the capacitor 19 decreases due to the discharge, and further, the cooling device 60 is driven by the electric power discharged by the capacitor 19 and is cooled by the cooling device 60. Therefore, the long life of the capacitor 19 is obtained while effectively using the electric power. It is possible to provide a hybrid-type construction machine that has been made simple.

  Furthermore, since the high temperature state can be prevented from continuing after the work is finished, the capacitor can be prevented from being deteriorated in the time after the work is finished when the capacitor is not driven.

  In the above description, the mode for determining whether the SOC of the capacitor 19 is 80% or less has been described. The SOC threshold is set to 80% in order to ensure a sufficient amount of charge when the hybrid construction machine is started next time and to secure a sufficient free capacity for charging regenerative power. is there. For this reason, the SOC threshold value used for the determination is not limited to 80%, and can be set as appropriate according to the specifications of the actual machine.

  In the above description, the threshold value of the integration time of the built-in timer of the controller 70 is 60 minutes. However, this threshold value is not limited to 60 minutes, and is appropriately set according to the capacitance of the capacitor 19 and the like. It is possible.

  When the capacitor voltage value is equal to or lower than a predetermined value when driving the cooling device 60, the controller 70 opens the switch 72 and closes the switch 80, thereby cooling with the electric power supplied from the battery 90. The device 60 may be driven.

  Even in such a case, since the capacitor 19 can be cooled, the life of the capacitor 19 can be extended.

  In the above, the embodiment in which the hybrid work machine of the present embodiment is applied to the hybrid construction machine including the motor generator 12 for assisting the engine 11 and the turning electric motor 21 has been described. The elements to be electrified are not limited to these, and can be similarly applied to a hybrid construction machine in which other work elements (for example, the lower traveling body 1, the arm 4, the boom 5, or the bucket 6) are electrified. It is.

  In the above, the hybrid work machine according to the present embodiment is applied to the hybrid construction machine in which the step-up / down converter 30 is disposed between the DC bus 40 to which the inverters 18 and 20 are connected and the capacitor 19. However, the arrangement and number of inverters and step-up / down converters are merely examples, and the same applies to other configurations.

“Embodiment 2”
The hybrid construction machine of the second embodiment is different from the hybrid construction machine of the first embodiment in that the stop of the cooling device 60 is determined based on the temperature of the capacitor 19 instead of the capacitor voltage value. Since other configurations are the same as those of the hybrid type construction machine of the first embodiment, the same or equivalent components are denoted by the same reference numerals, and description thereof is omitted.

  FIG. 4 is a block diagram showing the configuration of the hybrid construction machine of the second embodiment. In FIG. 4, the mechanical power system is indicated by a double line, the high-pressure hydraulic line is indicated by a solid line, the pilot line is indicated by a broken line, and the electric drive / control system is indicated by a one-dot chain line.

  The hybrid construction machine of the second embodiment is different from the first embodiment in that the capacitor temperature detection unit 110 is connected to the capacitor 19.

  The capacitor temperature detection unit 110 is a thermocouple thermistor provided in each of a plurality of capacitors included in the capacitor 19. A signal representing the capacitor temperature detected by the capacitor temperature detection unit 110 is transmitted to the controller 70.

  Moreover, the hybrid type construction machine of the second embodiment represents the capacitor voltage detected by the capacitor voltage detection unit 31 by determining the stop of the cooling device 60 based on the temperature of the capacitor 19 instead of the capacitor voltage value. The signal is transmitted only to the controller 50 and is not transmitted to the controller 70.

  In the second embodiment, the controller 70 is driven by the electric power supplied from the capacitor 19 when the capacitor temperature detected by the capacitor temperature detection unit 110 is equal to or higher than a predetermined value after the engine 11 is stopped. In order to cool 19 with the cooling device 60, electric power for driving the cooling device 60 is discharged to the capacitor 19, and the discharge is continued until the capacitor temperature becomes a predetermined threshold value or less.

  FIG. 5 is a diagram illustrating a processing procedure of drive control of the cooling device 60 executed by the controller 70.

  When the controller 70 receives a signal indicating that the engine 11 has been stopped from the controller 50, the controller 70 starts the processing shown in FIG. At this time, measurement of elapsed time by the built-in timer is started.

  First, the controller 70 starts driving the cooling device 60 (step S21). Specifically, the CPU 71 of the controller 70 closes the switch 72 and steps down the power (voltage value is about 360V) supplied from the capacitor 19 by the DC-DC converter 73 (to 24V) to the cooling device 60. Supply. Thereby, the electric fan of the cooling device 60 is rotationally driven, and the capacitor 19 is cooled.

  Next, the controller 70 measures the capacitor temperature (step S22). Specifically, the controller 70 receives a signal representing the capacitor temperature from the capacitor temperature detection unit 110.

  Further, the controller 70 compares the capacitor temperature with a predetermined threshold value to determine whether or not the capacitor temperature has become equal to or lower than the predetermined threshold value (step S23). The predetermined threshold is set to 40 degrees, for example.

  When the capacitor temperature is equal to or lower than the predetermined threshold (YES in step S23), it is determined that the capacitor 19 has been sufficiently discharged and cooled, and the controller 70 advances the procedure to step S24.

  The controller 70 stops the cooling device 60 (step S24). This is realized by the CPU 71 opening the switch 72.

  By the way, when it is determined in step S23 that the capacitor temperature is higher than the predetermined threshold (NO in step S23), the controller 70 proceeds with the procedure to step S25, and whether the integrated time of the built-in timer has passed the predetermined time. It is determined whether or not (step S25).

  When the integration time of the built-in timer has passed the predetermined time (YES in step S25), the controller 70 determines that the capacitor 19 has been sufficiently discharged and cooled, and advances the procedure to step S24 to cool the cooling device. 60 is stopped. Note that the predetermined time here is, for example, 60 minutes, so that the controller 70 can operate even if the capacitor temperature detected by the capacitor temperature detection unit 110 is abnormal (for example, by driving the cooling device 60). This is a case in which the capacitor temperature does not decrease despite being present.) The cooling device 60 can be appropriately stopped.

  On the other hand, when it is determined that the accumulated time of the built-in timer has not passed the predetermined time (threshold value) (NO in step S25), the controller 70 is insufficient in discharging and cooling the capacitor 19, and the capacitor temperature is also low. It is determined that it is still high, the procedure is returned to step S22, and steps S22, S23, and S25 are repeated.

  Thus, the drive control of the cooling device 60 by the controller 70 is completed.

  As described above, according to the hybrid construction machine of the second embodiment, after the engine 11 is stopped, the cooling device 60 is driven using the electric power charged in the capacitor 19 to discharge the capacitor 19. At the same time, the temperature of the capacitor 19 can be lowered to a predetermined value (in this embodiment, 40 degrees).

  Although the case where the predetermined threshold value of the capacitor temperature is 40 degrees has been described above, this threshold value is not limited to 40 degrees and can be set as appropriate according to the capacitance of the capacitor 19 and the like. is there.

  In the above description, the threshold value of the integration time of the built-in timer of the controller 70 is 60 minutes. However, this threshold value is not limited to 60 minutes, and is appropriately set according to the capacitance of the capacitor 19 and the like. It is possible.

“Embodiment 3”
The hybrid construction machine of the third embodiment includes a capacitor temperature detection unit 110 as in the hybrid construction machine of the second embodiment (see FIG. 4), and a signal representing the detected capacitor temperature is transmitted to the controller 70. The

  A signal representing the capacitor voltage detected by the capacitor voltage detector 31 is also transmitted to the controller 70.

  FIG. 6 is a diagram illustrating a processing procedure of drive control of the cooling device 60 executed by the controller 70 of the hybrid type construction machine of the third embodiment. Steps S31 to S34 in this processing procedure correspond to steps S11 to S13 and S15 in the first embodiment, respectively. Steps S35 to S38 correspond to steps S22 to S25 in the second embodiment.

  When the controller 70 receives a signal indicating that the engine 11 has been stopped from the controller 50, the controller 70 starts the processing shown in FIG. At this time, measurement of elapsed time by the built-in timer is started.

  First, the controller 70 starts driving the cooling device 60 (step S31). Specifically, the CPU 71 of the controller 70 closes the switch 72 and steps down the power (voltage value is about 360V) supplied from the capacitor 19 by the DC-DC converter 73 (to 24V) to the cooling device 60. Supply. Thereby, the electric fan of the cooling device 60 is rotationally driven, and the capacitor 19 is cooled.

  Next, the controller 70 measures the capacitor voltage (step S32). Specifically, the controller 70 receives a signal representing the capacitor voltage value from the capacitor voltage detection unit 31.

  Further, the controller 70 compares the capacitor voltage value with a predetermined threshold value to determine whether or not the capacitor voltage value has become equal to or lower than the predetermined threshold value (step S33). For example, the predetermined threshold is set to 80% in the SOC (State of charge) of the capacitor 19.

  If the capacitor voltage value is equal to or lower than the predetermined threshold (YES in step S33), it is determined that the capacitor 19 has been sufficiently discharged, and the controller 70 advances the procedure to step S35.

  Here, when it is determined in step S33 that the capacitor voltage value is higher than the predetermined threshold value (NO in step S33), the controller 70 advances the procedure to step S34, and the integrated time of the built-in timer is set to the predetermined time T1. It is determined whether or not the time has elapsed (step S34).

  When the integration time of the built-in timer has passed the predetermined time T1 (YES in step S34), the controller 70 determines that the capacitor 19 has been sufficiently discharged, and advances the procedure to step S35. The predetermined time T1 here is, for example, 60 minutes.

  On the other hand, when it is determined that the integration time of the built-in timer has not passed the predetermined time T1 (NO in step S34), the controller 70 indicates that the discharge of the capacitor 19 is insufficient and the capacitor voltage value is still high. The determination is made to return the procedure to step S32, and steps S32 to S34 are repeated.

  Next, the controller 70 measures the capacitor temperature (step S35). Specifically, the controller 70 receives a signal representing the capacitor temperature from the capacitor temperature detection unit 110.

  Further, the controller 70 compares the capacitor temperature with a predetermined threshold value to determine whether or not the capacitor temperature has become equal to or lower than the predetermined threshold value (step S36). The predetermined threshold is set to 40 degrees, for example.

  When the capacitor temperature is equal to or lower than the predetermined threshold (YES in step S36), the controller 70 determines that the capacitor 19 has been sufficiently discharged and cooled, and advances the procedure to step S37.

  The controller 70 stops the cooling device 60 (step S37). This is realized by the CPU 71 opening the switch 72.

  By the way, when it is determined in step S36 that the capacitor temperature is higher than the predetermined threshold (NO in step S36), the controller 70 advances the procedure to step S38, and the integrated time of the built-in timer has passed the predetermined time T2. It is determined whether or not (step S38).

  When the integration time of the built-in timer has passed the predetermined time T2 (YES in step S38), the controller 70 determines that the capacitor 19 has been sufficiently discharged and cooled, and proceeds the procedure to step S37 to cool the cooling. The device 60 is stopped. The predetermined time T2 here is, for example, 60 minutes.

  On the other hand, when it is determined that the integration time of the built-in timer has not passed the predetermined time (threshold value) (NO in step S38), the controller 70 has insufficient cooling of the capacitor 19 and the capacitor temperature is still high. The controller 70 returns the procedure to step S35 and repeats steps S35, S36, and S38.

  Thus, the drive control of the cooling device 60 by the controller 70 is completed.

  Thus, according to the hybrid type construction machine of the third embodiment, after the engine 11 is stopped, the cooling device 60 is driven using the electric power charged in the capacitor 19 to cool the capacitor 19. At the same time, the SOC of the capacitor 19 can be reduced to a predetermined value (80% in this embodiment).

  In addition, by detecting the temperature of the capacitor 19 and reducing it to a predetermined value (40 degrees in this embodiment), the capacitor 19 can be sufficiently cooled using the power of the capacitor 19.

  As a result, the SOC of the capacitor 19 decreases due to the discharge, and further, the cooling device 60 is driven by the electric power discharged by the capacitor 19 and is cooled by the cooling device 60. Therefore, the long life of the capacitor 19 is obtained while effectively using the electric power. It is possible to provide a hybrid-type construction machine that has been made simple.

  The SOC threshold value and the capacitor temperature threshold value can be set as appropriate according to the capacitance of the capacitor 19 and the like, as in the first or second embodiment.

  Further, the predetermined times T1 and T2 in steps S34 and S38 are not limited to 60 minutes, and can be appropriately set according to the capacitance of the capacitor 19 and the like. The predetermined times T1 and T2 can be set independently.

  Further, in the third embodiment, the controller 70 first performs the process of comparing the capacitor voltage value and the threshold value (steps S32 to S34), and then compares the capacitor temperature and the threshold value (steps S35 to S35). Step S38) is executed, but these processes are out of order and may be executed simultaneously in parallel.

“Embodiment 4”
The hybrid construction machine of the fourth embodiment includes a capacitor temperature detection unit 110 as in the hybrid construction machines of the second and third embodiments (see FIG. 4), and a signal indicating the detected capacitor temperature is sent to the controller 70. Is transmitted.

  A signal representing the capacitor voltage detected by the capacitor voltage detector 31 is also transmitted to the controller 70.

  FIG. 7 is a diagram illustrating a processing procedure of drive control of the cooling device 60 executed by the controller 70 of the hybrid type construction machine of the fourth embodiment.

  When the controller 70 receives a signal indicating that the engine 11 has been stopped from the controller 50, the controller 70 starts the processing shown in FIG. At this time, measurement of elapsed time by the built-in timer is started.

  First, the controller 70 starts driving the cooling device 60 (step S41). Specifically, the CPU 71 of the controller 70 closes the switch 72 and steps down the power (voltage value is about 360V) supplied from the capacitor 19 by the DC-DC converter 73 (to 24V) to the cooling device 60. Supply. Thereby, the electric fan of the cooling device 60 is rotationally driven, and the capacitor 19 is cooled.

  Next, the controller 70 measures the capacitor voltage and the capacitor temperature (step S42). Specifically, the controller 70 receives a signal representing the capacitor voltage value from the capacitor voltage detector 31 and receives a signal representing the capacitor temperature from the capacitor temperature detector 110.

  Thereafter, the controller 70 sets the driving time of the cooling device using the measured capacitor voltage, capacitor temperature, and time table (step S43).

  The time table is a reference table that represents the relationship between the capacitor voltage and capacitor temperature and the appropriate driving time of the cooling device. For example, the time table is stored in advance in the internal memory of the controller 70, and the controller 70 stops the engine 11. Based on the capacitor voltage and capacitor temperature at the time, it is possible to determine an appropriate driving time of the cooling device 60 (hereinafter referred to as “cooling device driving time”) necessary to sufficiently discharge and cool the capacitor 19. Like that.

  FIG. 8 is a diagram illustrating a configuration example of a time table used for setting the cooling device driving time, in which six levels of capacitor voltage V [V] are arranged in the vertical direction and six levels of capacitors are arranged in the horizontal direction. A level of temperature T [° C.] is arranged. The cooling device driving time is set in units of minutes, increases as the capacitor voltage V [V] increases, and increases as the capacitor temperature T [° C.] increases.

  FIG. 8 shows, for example, when the capacitor voltage and the capacitor temperature at the time when the engine 11 is stopped are 320 [V] and 47 [° C.], respectively, the cooling required to sufficiently discharge and cool the capacitor 19. When the device drive time is 30 [minutes] and the capacitor voltage and the capacitor temperature at the time of stopping the engine 11 are 370 [V] and 62 [° C.], respectively, the capacitor 19 is sufficiently discharged. And it shows that the cooling device drive time required for cooling is 55 [minutes].

  The controller 70 that has set the cooling device driving time in this way compares the elapsed time with the cooling device driving time while monitoring the elapsed time since the cooling device 60 started driving (step S44).

  When the elapsed time is less than the cooling device driving time (NO in step S44), the controller 70 continues to monitor the elapsed time without stopping the cooling device 60.

  On the other hand, when the elapsed time is equal to or longer than the cooling device driving time (YES in step S44), the controller 70 determines that the capacitor 19 has been sufficiently discharged and cooled, and stops the cooling device 60 (step). S45).

  Thus, the drive control of the cooling device 60 by the controller 70 is completed.

  Thus, according to the hybrid type construction machine of the fourth embodiment, after the engine 11 is stopped, the capacitor 19 is discharged by driving the cooling device 60 using the electric power charged in the capacitor 19. At the same time, the temperature of the capacitor 19 can be lowered to a predetermined value (in this embodiment, less than 40 degrees).

  In the fourth embodiment, the time table prepares 6 levels for each of the capacitor voltage V [V] and the capacitor temperature T [° C.], but prepares a level of less than 6 levels or a level of 7 levels or more. Alternatively, the number of levels of the capacitor voltage V [V] may be different from the number of levels of the capacitor temperature T [° C.].

  In the time table, the number of either one of the capacitor voltage V [V] and the capacitor temperature T [° C.] may be one step, or both of them may be one step.

FIG. 9 is a reference table that is a generalization of the time table shown in FIG. 8, in which N + 1 level (N is a natural number of 1 or more) capacitor voltage V [V] levels are arranged in the vertical direction, and the horizontal direction. The level of the capacitor temperature T [° C.] in M + 1 stages (M is a natural number of 1 or more) is arranged. The cooling device driving time A _{N, M} [min] is the cooling device driving time corresponding to the Nth level capacitor voltage V [V] and the Mth level capacitor temperature T [° C.], and is set in units of minutes. Is done. Note that each of the cooling device driving times A _{N, M} [min] does not necessarily increase as the capacitor voltage V [V] increases, or does not need to increase as the capacitor temperature T [° C.] increases. It may be a value.

Each of the cooling device driving times A _{N, M} [minutes] is a value set in advance based on a bench test, and is dynamically adjusted according to the environmental temperature, environmental humidity, current time, current position, and the like. May be.

  Further, in the hybrid type construction machine of the fourth embodiment, the controller 70 monitors only the elapsed time without measuring the capacitor voltage V [V] and the capacitor temperature T [° C.] once the cooling device driving time is set. Therefore, the power supply to the capacitor voltage detection unit 31 and the capacitor temperature detection unit 110 can be stopped, and wasteful power consumption can be avoided.

  Further, the controller 70 opens the switch 72 and closes the switch 80 when the capacitor voltage value becomes equal to or lower than the predetermined value before the cooling device driving time elapses. Then, the driving of the cooling device 60 may be continued.

  Although the hybrid type construction machine has been described above, the hybrid type work machine may be a work machine of a form other than the construction machine, for example, a hybrid type load handling machine (a crane or a forklift). .

  For example, the engine 11 and the motor generator 12 shown in FIG. 2 are used as the crane engine and the assist motor generator, and the turning electric motor 21 shown in FIG. 2 is used to raise or lower parts, cargo, etc. in the crane handling operation. Can be used as a power source. In particular, the power source for raising or lowering parts, cargo, etc. is used as a hybrid work machine because it performs powering operation (when winding) and regenerative operation (when pulling out) along with winding or pulling out wires. It can be implemented in the same manner as the hybrid construction machine described above.

  Similarly, in the case of a forklift, the engine 11 and motor generator 12 shown in FIG. 2 are used as a forklift engine and an assist motor generator, and the turning electric motor 21 shown in FIG. Alternatively, it may be used as a power source for lowering. In particular, the power source for raising or lowering the fork performs a power running operation (when it is raised) and a regenerative operation (when it is lowered) as it moves up and down, so that it is a hybrid type work machine similar to the above-mentioned hybrid type construction machine. Can be implemented.

  The hybrid working machine according to the exemplary embodiment of the present invention has been described above, but the present invention is not limited to the specifically disclosed embodiment, and departs from the scope of the claims. Various modifications and changes are possible.

DESCRIPTION OF SYMBOLS 1 Lower traveling body 1A, 1B Hydraulic motor 2 Turning mechanism 3 Upper turning body 4 Boom 5 Arm 6 Bucket 7 Boom cylinder 8 Arm cylinder 9 Bucket cylinder 10 Cabin 11 Engine 12 Motor generator 13 Reducer 14 Main pump 15 Pilot pump 16 High pressure Hydraulic line 17 Control valve 18 Inverter 19 Capacitor 20 Inverter 21 Rotating motor 22 Resolver 23 Mechanical brake 24 Rotating speed reducer 25 Pilot line 26 Operating device 27, 28 Hydraulic line 29 Pressure sensor 30 Buck-boost converter 31 Capacitor voltage detector 32 Capacitor current Detection unit 40 DC bus 41 DC bus voltage detection unit 50 Controller 60 Cooling device 70 Controller 80 Switch 90 Battery 100 Generator 11 Capacitor temperature detector

Claims (8)

In a hybrid work machine including a motor generator for assisting an engine and a capacitor for supplying electric power to the motor generator or charging regenerative power,
A cooling device for cooling the capacitor;
A drive control unit that performs drive control of the cooling device,
The drive control unit is a hybrid work machine that drives the cooling device with electric power supplied from the capacitor after the engine is stopped. A voltage detector for detecting a voltage value of the capacitor;
The hybrid work machine according to claim 1, wherein the drive control unit performs drive control of the cooling device based on a voltage value of a capacitor detected by the voltage detection unit.   The hybrid work machine according to claim 2, wherein the drive control unit drives the cooling device until the voltage value of the capacitor detected by the voltage detection unit falls to a predetermined voltage value. A temperature detection unit for detecting the temperature of the capacitor;
The hybrid work machine according to claim 1, wherein the drive control unit performs drive control of the cooling device based on a temperature detected by the temperature detection unit.   The hybrid work machine according to claim 4, wherein the drive control unit drives the cooling device until a temperature of the capacitor becomes equal to or lower than a predetermined temperature.   A secondary battery is connected to the cooling device, and when the voltage value of the capacitor detected by the voltage detection unit is lower than a predetermined voltage value, the drive control unit controls the power supplied from the capacitor. Instead, the hybrid work machine according to any one of claims 1 to 5, wherein the cooling device is driven by electric power supplied from the secondary battery. A timer for measuring the driving time of the cooling device;
The hybrid work machine according to any one of claims 1 to 6, wherein the drive control unit stops driving the cooling device when a drive time measured by the timer elapses a predetermined time. A voltage detector for detecting a voltage value of the capacitor;
A temperature detector for detecting the temperature of the capacitor;
A timer for measuring the driving time of the cooling device, and
The drive control unit sets an appropriate driving time of the cooling device based on the voltage value of the capacitor detected by the voltage detection unit and the temperature of the capacitor detected by the temperature detection unit, and is measured by the timer The hybrid work machine according to claim 1, wherein when the driving time has passed the appropriate driving time, driving of the cooling device is stopped.

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