JP6201679B2 - Construction machinery - Google Patents

Description

  The present invention relates to a hybrid or electric construction machine equipped with a capacitor.

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

  In a hybrid excavator, a generator motor is connected to an engine as a power source, and a capacitor is charged by the generator action of the generator motor. When appropriate, the generator motor is caused to act as a motor by the capacitor power to assist the engine. Composed.

  Further, as a turning drive system for turning the upper turning body, an electric turning unit using a turning electric motor as a drive source is provided instead of or in addition to the hydraulic turning unit using a turning hydraulic motor as a drive source, and the turning drive is performed. At the time (acceleration including start-up and steady operation after acceleration; also referred to as powering), the upper revolving body is driven to turn by the power of the generator motor or capacitor, and the turning motor is operated as a generator at the time of turning deceleration, It is well known that the brake force is exerted and the regenerative power is charged in a battery (see Patent Documents 1 and 2).

  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.Therefore, in the low temperature environment such as winter, the condenser is also heated to an appropriate temperature like the engine. It is desirable to take measures to warm up.

  As a countermeasure against this warm-up, as shown in Patent Document 2, when the temperature of the capacitor becomes lower than the set value, the generator motor is operated to force the capacitor to charge and discharge, and by internal heating A technique for increasing the temperature of the battery has been proposed.

JP-A-2005-290882 JP 2010-127271 A

  In general, the internal resistance of the battery is set small from the viewpoint of improving system efficiency.

  For this reason, according to the known technique of Patent Document 2 in which internal heat generation due to the internal resistance of the battery is used for warming up, the heat generation amount of the battery is small and the warming-up efficiency is poor, and it takes a long time to warm up the battery.

  Moreover, there exists a problem that a capacitor | condenser lifetime will become short if a capacitor | condenser repeats charging / discharging at low temperature.

  Therefore, the present invention provides a construction machine that can efficiently warm up a capacitor in a short time and without adversely affecting the lifetime of the capacitor.

As means for solving the above problems, in the present invention, a hydraulic pump, a hydraulic actuator using the hydraulic pump as a hydraulic source, a hydraulic actuator circuit connecting the hydraulic actuator, the hydraulic pump and the tank, and the hydraulic actuator A control valve provided in a circuit for controlling supply and discharge of hydraulic oil to and from the hydraulic actuator; an operating means for operating the control valve; an electric motor; and a capacitor serving as a power source for the electric motor. In the construction machine having a pump line for supplying the hydraulic pump discharge oil to the hydraulic actuator via the control valve, and a return line for returning the return oil from the hydraulic actuator to the tank, the temperature of the capacitor Capacitor temperature detection Providing a stage, a control means, and a warm-up line for warming up the battery, and connecting the inlet side of the warm-up line to the return line of the hydraulic actuator circuit and the outlet side to the tank, Provided on the inlet side of the warm-up line is a switching valve that switches between an open position for passing oil in the warm-up line and a closed position for shutting off oil in the warm-up line. When the temperature is equal to or lower than a preset warm-up value as a temperature at which warming-up is to be started, the condenser warm-up control is performed so that the return oil from the hydraulic actuator is passed through the warm-up line with the switching valve opened. It is configured to do.

  According to this configuration, since the return oil of the hydraulic actuator circuit is returned to the tank via the warm-up line of the capacitor, the capacitor is warmed up more efficiently in a short time compared to the method of warming up by internal heat generation of the capacitor. be able to.

  In addition, unlike the internal heat generation method, there is no possibility that the life of the capacitor will be reduced due to charging / discharging action at low temperatures, and there is no possibility that the normal operation of the hydraulic actuator circuit will be hindered due to warm-up.

  Furthermore, since the return oil heat generated in the existing hydraulic actuator circuit is used for warming up, no extra energy is required for warming up, and additional equipment is essentially only a switching valve. This is advantageous in terms of cost.

  In the above configuration, oil that has passed through the control valve during operation and is heated by working with a hydraulic actuator is sent to the warm-up line, and when not operated, relief oil or unload oil, that is, valve pressure loss (invoice) In item 2, oil heated to high temperature by pressure loss at the relief valve) is sent to the warm-up line.

  In addition, the “motor” in claim 1 refers to one or both of a generator motor and a work motor (for example, a swing motor) in a hybrid construction machine, and a motor and a work motor as a drive source in an electric construction machine. One or both of them.

In the present invention, an operation detection means for detecting operation / non-operation of the operation means and an operation amount is provided, and a relief pipe having a relief valve is provided between a pump pipe and a return pipe of the hydraulic actuator circuit. In addition, an unload pipeline having an unload valve is provided in parallel, and the control means controls the opening degree of the unload valve according to the operation amount, while as the capacitor warm-up control,
(i) When operating the operating means, return oil that has exited the hydraulic actuator and passed through the control valve is passed through the warm-up line,
(ii) When the operation means is not operated, it is desirable to perform a relief warm-up control in which the unload valve is closed and the relief valve is operated to allow relief oil to pass through the warm-up line. 2, 3).

  According to this configuration, as the condenser warm-up control, when the non-operation is performed, a higher temperature return oil called relief oil is passed through the warm-up line. Can be quickly warmed up to an appropriate temperature and ready for operation.

  In this case, it is desirable that a variable displacement pump is used as the hydraulic pump, and the control means is configured to reduce the capacity of the hydraulic pump compared to the normal time during the leaf warm-up control.

  The situation requiring the warm-up of the battery 4 occurs when the outside air temperature is particularly low as described above, and the engine output torque is low at low temperatures. Therefore, when the hydraulic pump is operated at the maximum load in this situation, the torque is insufficient. There is a problem such as occurrence of a drop.

  Therefore, the engine load can be reduced by reducing the pump capacity when the relief is warmed up as in claim 3.

  On the other hand, it is desirable to provide the condenser with a cooling line for cooling the condenser with the refrigerant supplied from the cooling pump, and to limit the amount of refrigerant supplied from the cooling pump during the condenser warm-up control. Item 4).

  According to this configuration, in a system provided with a condenser cooling line, the refrigerant supply is limited (stopped or reduced) during condenser warm-up control, so that good warm-up efficiency can be maintained.

  According to the present invention, the capacitor can be warmed up efficiently in a short time without adversely affecting the lifetime of the capacitor.

It is a system configuration figure showing an embodiment of the present invention. It is a flowchart for demonstrating the effect | action of embodiment. It is a figure which shows the relationship between a lever operation amount and an unload valve opening degree.

  The embodiment is applied to a hybrid excavator.

  As shown in FIG. 1, a generator motor 2 that performs a generator action and a motor action is connected to an engine 1 as a power source, and this generator motor 2 performs a generator action by driving the engine under the control of an inverter 3. The charged electric power is sent to the battery 4 and charged.

  On the other hand, when the required torque of the hydraulic actuator exceeds the engine output torque, the generator motor 2 performs an electric motor action with the electric power of the battery 4 to assist the engine 1.

  In addition, a hydraulic pump 5 is connected to the generator 1 and a tandem (may be parallel) as shown in the figure, and the hydraulic pump 5 and the hydraulic tank 6 and a plurality of hydraulic actuators (only one hydraulic cylinder is shown in the figure). 7) is connected by a hydraulic actuator circuit 8.

  As the hydraulic pump 5, a variable displacement pump whose capacity is controlled by a regulator 5a is used.

  The hydraulic actuator circuit 8 includes a control valve 9 that controls supply and discharge of oil to and from the hydraulic actuator 7, a pump line 10 that supplies pump discharge oil to the hydraulic actuator 7 via the control valve 9, and oil discharged from the hydraulic actuator 7. And a return line 11 for returning the pressure to the hydraulic tank 6.

  Further, a relief line 13 having a relief valve 12 and an unload line 15 having an unload valve 14 are provided in parallel with each other between the pump line 10 and the return line 11.

  Reference numeral 16 denotes a back pressure valve provided in the return line 11 in order to apply a constant back pressure to the return oil.

  The unload valve 14 is configured as a hydraulic pilot valve whose opening degree is controlled between fully open and fully closed by a pilot pressure input to the pilot port, and the opening degree is controlled through the unload control valve 18 by a controller 17 as a control means. Be controlled.

  In the figure, 19 is a pilot hydraulic pressure source of the unload valve 14.

  Reference numeral 20 denotes a remote control valve as an operating means operated by a lever. The control valve 9 is switched and controlled in accordance with the operation direction and operation amount of the remote control valve 20 to control the operation direction and speed of the hydraulic actuator 7. Hereinafter, according to a common name, the operation of the remote control valve 20 is referred to as “lever operation”, and the operation amount thereof is referred to as “lever operation amount”.

  The battery 4 is provided with a temperature management plate 21 for cooling or warming it up.

  A cooling line 23 for flowing a refrigerant (water, oil, etc.) from the cooling pump 22 and a warm-up line 24 for flowing return oil (high temperature hydraulic oil) from the hydraulic actuator circuit 8 are passed through the temperature management plate 21. The condenser 4 is cooled or warmed up through the temperature control plate 21 by both the lines 23 and 24. In the figure, 25 is a refrigerant tank, and 26 is a cooler provided at the refrigerant tank inlet of the cooling line 23.

  The warm-up line 24 is connected to the return line 11 on the inlet side and the hydraulic tank 6 on the outlet side, and an electromagnetic switching valve 27 that is switched and controlled by the controller 17 is provided on the inlet side of the warm-up line 24. ing.

  The switching valve 27 switches between an open position (a) through which oil passes and a closed position (b) through which the oil is blocked, and the return oil of the hydraulic actuator circuit 8 is introduced into the warm-up line 24 at the open position a.

  On the other hand, as a detecting means, a pilot pressure sensor 28 as an operation detecting means for detecting whether the lever is operated / not operated by the pilot pressure of the remote control valve 20 and an operation amount, and a condenser temperature detecting means for detecting the temperature of the condenser 4 A temperature sensor 29 is provided, and an operation signal and a temperature signal detected by both the sensors 28 and 29 are input to the controller 17.

  The controller 17 performs capacitor warm-up control for increasing the capacitor temperature at a low temperature based on the input operation and temperature signals.

  The operation of the controller 17 will be described with reference to the flowchart of FIG.

  For example, the control is started by starting the engine. First, in step S1, whether or not the detected capacitor temperature T1 is lower than a warm-up set value Ta set in advance as a temperature at which the warm-up of the capacitor 4 is to be started (warm-up). Whether or not a machine is necessary).

  If NO (no warm-up is required), it is determined in step S2 whether or not there is no lever operation. If YES (no lever operation), the unload valve 14 is fully opened in step S3.

  Here, the hydraulic pump 5 discharges the maximum flow rate with the maximum capacity, and all of the pump discharge oil is returned to the hydraulic tank 6 through the unload valve 14.

  If NO in step S2 (with lever operation), as the normal control, in step S4, the opening of the unload valve 14 is controlled to decrease with a large operation amount according to the lever operation amount as shown in FIG. To do. That is, surplus oil other than the flow rate required for the hydraulic actuator 7 is unloaded.

  In step S5 following step S3 or step S4, the pump displacement is set to “normal”, that is, maximum, and in step S6, the switching valve 27 is set to the closed position B.

  Further, in step S7, it is determined whether or not the storage battery temperature T1 is higher than a cooling set value Tb set in advance as a temperature at which the storage battery 4 should start to be cooled. If YES, the cooling pump 22 is operated. Therefore, the refrigerant is supplied to the cooling line 23, and the condenser 4 is cooled by heat exchange in the temperature management plate 21.

  On the other hand, if YES in step S1, that is, if it is determined that the condenser temperature T1 is lower than the warm-up set value Ta, the cooling pump 22 is stopped in step S9, and the switching valve 27 is opened and switched to the position A in step S10. .

  As a result, the posture (warm-up posture) in which the return oil of the hydraulic actuator circuit 8 is supplied to the warm-up line 24 via the switching valve 27 is adjusted.

  In step S11, it is determined whether or not there is no lever operation. If NO (with lever operation), normal control of the unload valve 14 (opening control according to the lever operation amount) is performed in step S12, and in step S13. The pump capacity is “normal (maximum)”.

  As a result, the hydraulic actuator 7 is supplied with a flow rate corresponding to the amount of lever operation, and the hydraulic actuator 7 is operated. The oil that has come out of the hydraulic actuator 7 and the oil that has passed through the unload valve 14 pass through the switching valve 27 and is warmed. It flows through the machine line 24 and is returned to the hydraulic tank 6.

  In this way, as the condenser warm-up control at the time of lever operation, the return oil that has been heated by passing through the control valve 9 and working by the hydraulic actuator 7 and the return oil that has been heated by pressure loss at the unload valve 14, The condenser 4 is warmed up through the temperature management plate 21.

  On the other hand, if YES in step S11 (no lever operation), since the return oil from the hydraulic actuator 7 is not sent to the warm-up line 24, relief warm-up control is performed instead.

  That is, in step S14, the pump displacement is reduced from the normal value q to the warm-up set value qT, thereby reducing the pump discharge amount, and in step S15, the unload valve 14 is fully closed.

  As a result, the relief valve 12 is activated, and the entire amount of pump discharge oil passes through the relief valve 12 and is sent to the warm-up line 24 via the switching valve 27.

  Thus, as a warm-up control when the lever is not operated, the capacitor 4 is warmed up by the oil heated to a high temperature by the relief operation.

  After steps S8, S13, and S15, the process returns to step S1, and the warm-up control is continued until the battery temperature T1 becomes equal to or higher than the warm-up set value Ta (warm-up completion).

  In this way, the return oil of the hydraulic actuator circuit 8, that is, the oil that has been heated by passing through the control valve 9 and working with the hydraulic actuator 7 when the lever is operated, and the temperature of the hydraulic actuator circuit 8 is increased by the pressure loss at the unload valve 14 Compared with the system in which the oil is warmed up by the internal heat generation of the capacitor 4 in order to pass the oil and the oil heated to high temperature due to the pressure loss at the relief valve 12 when the lever is not operated, respectively, It can warm up efficiently in a short time.

  Here, when the lever is not operated, a higher temperature return oil called relief oil is passed through the warm-up line 24, so that the capacitor is quickly warmed up to an appropriate temperature at the start of operation of the machine particularly in the winter when the outside air temperature is low. And can quickly prepare for driving.

  In addition, unlike the internal heat generation method, there is no possibility that the life of the electric storage device will be reduced due to the charging / discharging action at low temperature, and there is no possibility that the normal operation of the hydraulic actuator circuit 8 will be hindered due to warm-up.

  Furthermore, since the heat generated in the existing hydraulic actuator circuit 8 is used for warming up, no extra energy is required for warming up, and the additional equipment is essentially only the switching valve 27. This is advantageous in terms of cost.

  By the way, the situation requiring the warm-up of the battery 4 occurs when the outside air temperature is particularly low as described above, and since the output torque of the engine 1 is low at low temperatures, the hydraulic pump 5 is operated at the maximum load in this situation. There are problems such as engine drop due to insufficient torque.

  In this regard, as described above, the pump capacity is reduced when the relief is warmed up, so that the engine load can be reduced.

  In the embodiment, in the system provided with the cooling line 23, the cooling pump 22 is stopped and the refrigerant supply (capacitor cooling) is stopped during the capacitor warm-up control, so that a good warm-up efficiency can be maintained.

Other embodiments
(1) In the above embodiment, the cooling pump 22 is stopped (step S9 in FIG. 2) during the capacitor warm-up control to stop the supply of the refrigerant. However, the refrigerant discharge amount from the cooling pump 22 is prevented from being warmed up. You may make it reduce to the quantity which does not become.

  (2) In the above embodiment, the pump capacity is reduced during the relief warm-up control during the capacitor warm-up control. However, if the engine 1 does not have insufficient torque, the pump capacity may not be reduced. Good.

  (3) The present invention is not limited to a hybrid excavator, but also applies to a hybrid construction machine other than an excavator, or an electric construction machine configured to drive an electric motor with electric power stored in a capacitor and to drive a hydraulic pump with the electric motor. be able to.

DESCRIPTION OF SYMBOLS 4 Capacitor 5 Hydraulic pump 5a Regulator 6 Hydraulic tank 7 Hydraulic actuator 8 Hydraulic actuator circuit 9 Control valve 10 Pump line 11 Return line 12 Relief valve 13 Relief line 14 Unload valve 15 Unload line 17 Controller as control means DESCRIPTION OF SYMBOLS 18 Unload control valve 20 Remote control valve as operation means 21 Temperature control plate of condenser 22 Cooling pump 23 Cooling line 24 Warm-up line 27 Switching valve 28 Pilot pressure sensor as operation detection means 29 Temperature sensor as condenser temperature detection means

Claims (4)

A hydraulic pump, a hydraulic actuator using the hydraulic pump as a hydraulic source, a hydraulic actuator circuit connecting the hydraulic actuator to the hydraulic pump and the tank, and supply of hydraulic oil to the hydraulic actuator provided in the hydraulic actuator circuit A control valve for controlling the exhaust; operating means for operating the control valve; an electric motor; and a capacitor serving as a power source for the electric motor. The hydraulic actuator circuit discharges oil discharged from the hydraulic pump via the control valve. In a construction machine having a pump line for supplying to the hydraulic actuator and a return line for returning return oil from the hydraulic actuator to the tank, a condenser temperature detecting means for detecting the temperature of the condenser, a control means, Warm-up line that warms up the battery The door is provided, the inlet side of the warm-up line, the return line of the hydraulic actuator circuit, passing through the outlet as well as connected to the tank, the inlet side of the warm-up line, the oil in the warm-up line A switching valve that switches between an open position to be closed and a closed position to shut off oil in the warm-up line, and the control means has a warm-up temperature that is set in advance as a temperature at which the capacitor is to start warm-up. A construction machine configured to perform power storage warm-up control in which return oil from the hydraulic actuator is passed through the warm-up line with the switching valve being opened at a set value or less. An operation detection means for detecting operation / non-operation of the operation means and an operation amount is provided, a relief line having a relief valve between a pump line and a return line of the hydraulic actuator circuit, and an unload valve In parallel, an unload pipeline with the above-mentioned control means controls the opening degree of the unload valve according to the operation amount, while the capacitor warm-up control,
(i) When operating the operating means, return oil that has exited the hydraulic actuator and passed through the control valve is passed through the warm-up line,
(ii) When the operation means is not operated, the relief valve is operated by closing the unload valve and operating the relief valve to perform relief warm-up control for passing relief oil through the warm-up line. Item 1. The construction machine according to Item 1.   3. The construction machine according to claim 2, wherein a variable displacement pump is used as the hydraulic pump, and the control means is configured to reduce the capacity of the hydraulic pump during the relief warm-up control as compared with a normal time. .   The condenser is provided with a cooling line for cooling the condenser with a refrigerant supplied from a cooling pump, and the refrigerant supply amount from the cooling pump is limited during the condenser warm-up control. The construction machine of any one of 1-3.

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