JP2012140772A - Construction machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To warm up a capacitor under low temperature without using a specialized heating device and having a negative impact on a service life of the capacitor.SOLUTION: In a hybrid shovel having a generator motor 2, a capacitor 8 and a regeneration resistor 9, the capacitor 8 is arranged close to the regeneration resistor 9 so that heat generated by the regeneration resistor 9 heats and warms up the capacitor 8. A switch device 11 is installed in a circuit 10 connecting an inverter/converter 7 for the generator motor 2, the capacitor 8 and the regeneration resister 9 so that power from the generator motor 2 is sent to the regeneration resistor 9 by selecting the regeneration resister 9 with the switching device 11 when temperature of the capacitor 8 is equal to or lower than a set value.

Description

  The present invention relates to a construction machine such as an excavator configured to charge a storage battery with regenerative power of an electric motor and to consume regenerative power with a regenerative resistor as necessary.

  The background art will be described using a hybrid excavator as an example.

  In a hybrid excavator, a hydraulic pump and an electric motor that performs a generator action and an electric motor action (hereinafter referred to as a generator motor in accordance with a common name in a hybrid excavator) are connected to an engine, and a hydraulic actuator is driven by the hydraulic pump. The battery is charged by a generator action, and the generator motor is caused to perform a motor action by this battery power to assist the engine when appropriate.

  In this hybrid excavator, the capacity of the condenser decreases at low temperatures, and the capacity of the condenser (discharge performance) declines and sufficient electric power cannot be obtained, so the condenser is also heated to an appropriate temperature like an engine in a low temperature environment such as winter. It is desirable to take measures to warm up.

  As a countermeasure against this warm-up, it is conceivable to provide a dedicated heating device for the battery, but it is not practical because it requires extra cost.

  On the other hand, as a measure for warming up the battery without using a dedicated heating device, when the temperature of the battery becomes lower than the set value, the generator motor is operated to force the battery to charge / discharge, and the battery is heated by internal heating. A technique for raising the temperature (see Patent Document 1) is known.

JP 2010-127271 A

  However, charging at a low temperature generally leads to deterioration of the battery, and thus repeated charging and discharging for warming up shortens the life of the battery.

  In particular, in a capacitor having a low internal resistance, a large current flows due to charge / discharge, so that lithium deposition of the electrode is likely to occur, and therefore, deterioration is more likely to proceed.

  Accordingly, the present invention provides a construction machine that does not use a dedicated heating device and does not adversely affect the life of the battery.

  As means for solving the above-mentioned problems, the present invention comprises a power storage device, an electric motor that performs an electric motor action and an electric generator action, a regenerative resistor, and a control means. By this control means, the electric generator action of the electric motor is provided. In the construction machine that is configured to consume the electric power generated by the regenerative resistor as needed, the electric power generated by the regenerative resistor is heated and heated by the heat generated by the regenerative resistor. Provided with a capacitor temperature detecting means for detecting the temperature of the capacitor, the control means is a set value as a temperature at which the capacitor temperature detected by the capacitor temperature detecting means requires warming up The regenerative electric power of the electric motor is supplied to the regenerative resistor at the following times.

  According to this configuration, in a construction machine having a regenerative resistor for consuming heat generated by an electric motor as heat when charging is impossible such as when the electric condenser is fully charged or when the electric motor is in an emergency stop, the electric condenser temperature is a set value. Since power is supplied to the regenerative resistor and the generated heat is used for warming up the capacitor at the following times, the capacitor can be warmed up without using a dedicated heating device.

  In addition, there is no possibility of adversely affecting the life of the battery as in the case where the battery is forcibly charged / discharged at low temperatures.

  In the present invention, the electric motor is driven by an engine, and the control means sends electric power generated by the electric generator action of the electric motor (generator electric motor) to the electric accumulator and charges the electric motor. To assist the engine, and if necessary, the electric power generated by the electric motor can be consumed by the regenerative resistor (claim 2).

  That is, in a hybrid construction machine that uses both engine power and capacitor power, the power generated by the motor can be sent to the regenerative resistor to warm the capacitor.

  Further, in the present invention, an electric motor is provided as a drive source of a work device that operates on the drive side and the regenerative side, and the control means requires regenerative power generated by the work device motor during operation on the regenerative side of the work device. Accordingly, it can be configured to be consumed by the regenerative resistor (claim 3).

  That is, in a machine that drives a working device (for example, an upper swing body) with an electric motor (same as the swing electric motor), the electric power generated in the electric motor at the time of swing braking can be sent to the regenerative resistor to warm the capacitor.

  In the present invention, the control means includes power generation amount adjusting means for adjusting the power generation amount of the electric motor, and when the detected condenser temperature is equal to or lower than a set value, the power generation amount of the motor is more than when the detected value exceeds the set value. It is desirable to configure so as to increase (claim 4).

  According to this configuration, the regenerative resistor can be quickly heated to a high temperature by a large current when necessary, and the capacitor temperature can be quickly raised to an appropriate temperature.

  Further, in the present invention, a switching unit is provided in a circuit connecting the capacitor and the regenerative resistor and the motor, and the control unit uses the switching unit to switch the motor to a regenerative resistor when the capacitor temperature is equal to or lower than a set value. It is desirable that the battery is connected to the capacitors when the set value is exceeded (claim 5).

  In this way, when the temperature of the capacitor is lowered, the electric motor is connected only to the regenerative resistor and is cut off from the capacitor, so that the capacitor is not charged or discharged. For this reason, it is possible to avoid a reduction in the life of the battery due to charging and discharging being performed at a low temperature.

  In the present invention, it is desirable that the capacitor and the regenerative resistor are arranged close to each other so that the heat generated by the regenerative resistor is transmitted to the capacitor.

  As specific means for utilizing the heat generated by the regenerative resistor for warming up the capacitor, it is possible to arrange both of them separately and send the warm air generated by the heat generated by the regenerative resistor to the capacitor through a duct. In addition, by disposing them close to each other so that heat is directly transferred between them, an extra facility such as a duct becomes unnecessary and efficient warming-up of the battery is possible.

  According to the present invention, the battery can be warmed up at a low temperature without using a dedicated heating device and without adversely affecting the life of the battery.

It is a figure which shows the system configuration | structure concerning 1st Embodiment of this invention. It is a flowchart for demonstrating the effect | action of 1st Embodiment. It is a graph which shows the condition of the electrical storage device temperature by 1st Embodiment, the electric motor electric power generation amount, the power consumption of regenerative resistance, and electrical storage device charging power. It is a figure which shows the system configuration | structure concerning 2nd Embodiment of this invention.

  In the following embodiments, a hybrid excavator is applied.

1st Embodiment (refer FIGS. 1-3)
FIG. 1 shows a system configuration of the first embodiment.

  In FIG. 1, the power system circuit is indicated by a thick line, and the signal system circuit is indicated by a broken line.

  As shown in the figure, a motor (generator motor) 2 that performs a generator action and a motor action and a hydraulic pump 3 are connected to the engine 1 in tandem (may be parallel), and these are driven by the engine 1.

  The hydraulic pump 3 is provided with a hydraulic actuator 5 (for example, a boom, an arm, and a bucket cylinder in the case of an excavator) via a control valve (provided for each actuator, but shown here as an aggregate of a plurality of control valves). And a hydraulic motor for traveling, etc.) are connected, and the hydraulic actuator 5 is driven by the pressure oil supplied from the hydraulic pump 3.

  Although FIG. 1 shows a case where only one hydraulic pump 3 is connected, a plurality of units may be connected in series or in parallel.

  An accumulator 8 such as a nickel metal hydride battery or a lithium ion battery is connected to the generator motor 2 through an inverter / converter 7 that constitutes a control means together with the controller 6, and control from the inverter / converter 7 based on a command from the controller 6. Depending on the signal, charging / discharging action corresponding to the state of charge of the battery 8, switching between the generator action and the motor action of the generator motor 2, and the like are performed.

  That is, if the charge amount of the capacitor 8 decreases, the generator motor 2 performs a generator function, and the generated electric power is sent to the capacitor 8 to be charged. To assist the engine 1.

  Further, the inverter / converter 7 also functions as a power generation amount adjusting means for increasing the power generation amount of the generator motor 2 when the battery 8 is warmed up, as will be described later, than when it is not warmed up.

  On the other hand, a regenerative resistor 9 is provided for consuming the electric power generated by the generator motor 2 when the battery 8 is in a fully charged state and cannot be charged, or at the time of emergency stop of the machine.

  The regenerative resistor 9 and the capacitor 8 are arranged close to each other so that the heat generated by the regenerative resistor 9 is directly transmitted to the capacitor 8.

  Specifically, for example, the capacitor 8 and the regenerative resistor 9 are covered with one casing, and the capacitor 8 is heated (warmed up) by the heat generated by the regenerative resistor 9 in the casing.

  Or you may take the structure which covers both with a separate casing and distribute | circulates the air in both casings by a ventilation hole, or makes both casings closely_contact | adhere and heat-transfer.

  In addition, in the circuit 10 connecting the capacitor 8 and the regenerative resistor 9 and the generator motor 2 (inverter / converter 7), the connection partner of the generator motor 2 is connected between the capacitor 8 and the regenerative resistor 9 in accordance with a command from the controller 6. Is provided as a switching means for switching at (11).

  In the figure, 11a is a capacitor side contact of the switch device 11, 11b is the same regenerative resistor side contact, 12 is a capacitor side circuit connecting the capacitor side contact 11a and the capacitor 8, and 13 is a regenerative resistor side contact 11b and a regenerative resistor. 9 is a regenerative resistance side circuit that connects 9.

  Further, a temperature sensor 14 is provided as a capacitor temperature detecting means for detecting the temperature of the capacitor 8, and a capacitor temperature signal detected by the temperature sensor 14 is input to the controller 6.

  When the detected capacitor temperature is equal to or lower than a value (set value) set in advance as the upper limit value of the temperature range in which the capacitor 8 is to be warmed up, the controller 6 switches the switch device 11 to the regenerative resistor side circuit 13 side. And the amount of power generated by the generator motor 2 is increased more than when the set value is exceeded (hereinafter referred to as normal), and this electric power is sent to the regenerative resistor 9.

  The operation of this point will be described in detail with reference to the flowchart of FIG. 2 and the graph of FIG.

  As shown in FIG. 2, when the control is started, it is determined whether or not the storage battery temperature is equal to or lower than the set value. If NO (normal), the storage 8 is not required to be warmed up, and the process proceeds to step S2. The switch device 11 is set in the capacitor side circuit 12, and the electric power generated by the generator action of the generator motor 2 is sent to the capacitor 8 to be charged (step S3).

  On the other hand, if YES in step S1 (below the set value), it is assumed that the battery 8 needs to be warmed up. First, the switch device 11 is switched to the regenerative resistance side circuit 13 in step S4, and the generator motor 2 is switched in step S5. A command to increase the power generation amount is issued, and in step S6, the electric power [FIG. 3 (b)] generated by the generator motor 2 based on this command is sent to the regenerative resistor 9.

  As a result, the regenerative resistor 9 generates heat [FIG. 3 (c)], and the capacitor 8 is heated by the heat from the regenerative resistor 9 to raise the temperature [FIG. 3 (a)]. That is, the warming-up action of the battery 8 is performed.

  During the warming up of the capacitor, the power supplied to the capacitor 8 for charging is zero as shown in FIG.

  Further, when the capacitor temperature exceeds the set value due to the capacitor warm-up operation, the process proceeds from step S1 to step S2, and the switch device 11 performs the normal charging operation of the capacitor 8.

  Thus, since the power is supplied to the regenerative resistor 9 when the capacitor temperature is equal to or lower than the set value, and the heat generation is used to warm up the capacitor 8, the capacitor 8 can be connected without using a heating device dedicated to warming up. It is possible to warm up to a temperature at which good performance can be exhibited.

  In addition, there is no possibility of adversely affecting the life of the capacitor 8 as in the case where the capacitor 8 is forcibly charged / discharged at low temperatures.

  Further, in order to increase the power generation amount of the generator motor 2 when the condenser temperature is lower than the set value, the regenerative resistor 9 is quickly heated to a high temperature by a large current to reach the optimum temperature. It can be raised quickly.

Second embodiment (see FIG. 4)
Only differences from the first embodiment will be described.

  In the hybrid excavator in which the upper-part turning body is driven to turn by the turning electric motor 15, the second embodiment is configured to send the regenerative electric power generated in the turning electric motor 15 during turning braking to the regenerative resistor 9 to warm up the capacitor 8. ing.

  The swing motor 15 is controlled by a controller 6 and an inverter / converter 16 for a swing motor that constitutes a control unit together with the controller 6 and the inverter / converter 7 for the motor, based on an operation of an operation unit (not shown).

  The swing motor 15 is connected to the circuit 10 in parallel with the circuit of the generator motor 2 via the inverter / converter 16, and the electric power (swing regenerative power) generated at the time of swing braking is usually on the switch device 11 and the capacitor side. It is sent to the battery 8 through the circuit 12 as charging power.

  On the other hand, when the storage battery temperature is equal to or lower than the set value, the turning regenerative power is sent to the regenerative resistor 9 through the regenerative resistor side circuit 13 by the switching operation of the switch device 11 to the regenerative resistor side based on the command from the controller 6. Thus, the warm-up operation of the battery 8 is performed.

  In this case, it may be configured such that only the regenerative power of the swing motor 15 is sent to the regenerative resistor 9, or the power generated by the generator motor 2 may be sent together with the regenerative resistor 9. .

  Also according to the configuration of the second embodiment, it is possible to obtain basically the same functions and effects as those of the first embodiment.

  In addition, since the electric power generated by the generator motor 2 can be reduced, the energy consumption of the engine 1 can be reduced and the fuel consumption can be suppressed.

  By the way, the structure of 2nd Embodiment is applicable also to the hybrid shovel which uses a hydraulic unit and an electric unit together as a turning drive source.

  Further, as an application form of the second embodiment, in a hybrid excavator configured to drive other work devices such as a boom and an arm with an electric motor, the regenerative power of the motor for the other work device is other than the swivel regenerative power and the like. The regenerative power may be combined with the regenerative power or may be sent to the regenerative resistor 9 alone.

  Furthermore, the present invention is not limited to a hybrid construction machine other than a hybrid excavator, and is not limited to a hybrid construction machine. An electric motor that performs an electric motor action and an electric generator action, a capacitor that serves as an electric power source of the electric motor, and electric power generated by the electric generator action of the electric motor. It can be widely applied to construction machines with regenerative resistance to consume.

1 Engine 2 Electric motor (generator motor)
DESCRIPTION OF SYMBOLS 3 Hydraulic pump 6 Controller which comprises a control means 7 Same, inverter / converter 8 Accumulator 9 Regenerative resistor 10 Circuit which connects an electric motor, an accumulator, and a regenerative resistor 11 Switch apparatus 11a Accumulator side contact 11b Regenerative resistor side contact 12 Accumulator side circuit 13 Regenerative resistor side circuit 14 Temperature sensor (capacitor temperature detection means)
15 slewing motor 16 inverter / converter for slewing motor

Claims (6)

  A power storage device, a motor that performs a motor action and a power generator action, a regenerative resistor, and a control means; the control means sends power generated by the power generator action of the motor to the power storage device for charging. In the construction machine configured to consume the electric power with the regenerative resistor as necessary, the capacitor is provided in a state of being warmed up by being heated by the heat generated by the regenerative resistor and detecting the temperature of the capacitor. A storage battery temperature detecting means for providing the storage battery temperature when the storage battery temperature detected by the storage battery temperature detection means is equal to or lower than a preset upper limit value of the temperature range for warming up the storage battery. A construction machine configured to supply regenerative power of an electric motor to a regenerative resistor.   The electric motor is driven by the engine, and the control means assists the engine by driving the electric motor as an electric motor with the electric power generated by the electric generator generated by the electric motor. 2. The construction machine according to claim 1, wherein electric power generated by the electric motor is consumed by the regenerative resistor as necessary.   An electric motor is provided as a drive source for the work device that operates on the drive side and the regenerative side, and the control means regenerates the regenerative power generated by the work device motor during operation on the regenerative side of the work device, if necessary. The construction machine according to claim 1, wherein the construction machine is configured to be consumed by resistance.   The control means includes a power generation amount adjusting means for adjusting a power generation amount of the electric motor, and increases the power generation amount of the electric motor when the detected battery temperature is equal to or lower than a set value than when exceeding the set value. The construction machine according to any one of claims 1 to 3, wherein the construction machine is configured as described above.   A switching means is provided in the circuit connecting the capacitor and the regenerative resistor and the motor, and the control means causes the switch to turn the motor into a regenerative resistor when the capacitor temperature is equal to or lower than a set value, and when the set value exceeds the set value. The construction machine according to any one of claims 1 to 4, wherein the construction machine is configured to be connected to each of the capacitors.   The construction machine according to any one of claims 1 to 5, wherein the capacitor and the regenerative resistor are arranged close to each other so that heat generated by the regenerative resistor is transmitted to the capacitor.

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