JP5271500B2 - Battery-powered construction machinery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To preheat pressure oil that passes through a hydraulic circuit during charging, without having to add a special power circuit for preheating, or without having to use a timer. <P>SOLUTION: Battery-driven construction machine includes: a charger 22 that charges a battery 21 utilizing power from a commercial power supply 9; a voltage sensor 271 that detects the voltage on the output side of the charger 22; a current sensor 272 that detects the current on the output side of the charger 22; an oil temperature sensor 273 that detects the temperature of the pressure oil in the hydraulic circuit 25; a contactor 275 that controls supply and the stop of supply of power from the charger 22 to the battery 21; and a contactor 274 that controls supply and the stop of supply of power from the charger 22 to an inverter 23. The construction machine is provided with a controller 26 that appropriately switches between the contactor 275 and the contactor 274 to control the charging power of the charger 22 and power for heat generation, according to the signals outputted from the voltage sensor 271, the current sensor 272, and the oil temperature sensor 273. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to a battery-driven construction machine such as a battery-type hydraulic excavator having a battery, an electric motor driven by the electric power of the battery, and a hydraulic pump driven by the electric motor.

  Recently, as shown in Patent Document 1 as a hydraulic excavator, a battery-driven construction machine such as an environmentally friendly battery-type hydraulic excavator characterized by low noise and zero exhaust gas has been developed. A battery-type hydraulic excavator is configured to supply electric power stored in a battery to an electric motor, that is, an electric motor through an inverter, to drive the electric motor, and to drive an actuator by the electric motor. It has a configuration that does not have an engine. Such a battery-type hydraulic excavator is generally suitable for night work or the like in a residential suburb that is easily restricted by the work environment.

  Since the battery-type hydraulic excavator has a limited amount of power stored in the battery, efficient use of this battery power is required. For example, power is consumed for heating the cab, etc., except during work. Regarding the heating of the cab, in Patent Document 2, the heat of the pressure oil heated by the flow rate control valve, that is, the control valve, is heat-exchanged through the heat exchanger in accordance with the work. The one that warms the cab has been proposed.

  By the way, there is no problem because hot air is supplied into the cab when the pressure oil, that is, the hydraulic oil is warmed, for example, as shown in Patent Document 2 described above. Since it is not warmed, it cannot be heated by this hydraulic oil. For this reason, it is necessary to perform warm-up and preheat before starting the excavator.

As means for preheating hydraulic fluid, there are conventionally disclosed in Patent Document 3 in which preheating is performed using external electric power and in Patent Document 4 in which preheating is performed using electric power of a battery. The battery-driven construction machine of the present invention relates to charging of an electric vehicle of a different target, but Patent Document 5 proposes charging with a timer and then operating an air conditioner in the driver's seat. ing.
JP 2000-273913 A Japanese Utility Model Publication No. 5-10020 Japanese Patent Laid-Open No. 10-331205 JP-A-11-229430 JP-A-10-262305

  Among the prior arts that perform preheating of hydraulic oil before starting, the battery power shown in Patent Document 4 uses battery power for preheating, and thus cannot save battery power. Moreover, although the thing shown by patent document 3 uses external electric power, although consumption of battery power is suppressed, since it is necessary to attach the power circuit for preheating specially, it becomes a complicated structure and manufacturing cost Tends to be high. In addition, as shown in Patent Document 5, there is a problem that it takes time until the heating is performed by the air conditioner after charging by the timer.

  The present invention has been made from the above-described prior art, and its purpose is to provide a hydraulic fluid that flows through a hydraulic circuit during charging without a special power circuit for preheating and without using a timer. It is an object of the present invention to provide a battery-powered construction machine capable of preheating.

In order to achieve the above object, the present invention provides a battery, an inverter for controlling battery power, an electric motor driven by output power of the inverter, a hydraulic pump driven by the electric motor, and a discharge from the hydraulic pump. In a battery-driven construction machine comprising a hydraulic circuit including a valve mechanism for generating heat in pressure oil, and heat exchange means for exchanging heat of the pressure oil warmed in the hydraulic circuit, the battery is supplied from an external power source. A charging means for charging using the electric power, a voltage detecting means for detecting a voltage on the output side of the charging means, a current detecting means for detecting a current on the output side of the charging means, and the pressure of the hydraulic circuit. Oil temperature detecting means for detecting the temperature of the oil, first switching means for controlling supply and stop of power supply from the charging means to the battery, and from the charging means to the inverter Supply of power to, and a second switching means for controlling the supply stop, the operation of the charging means, switching the first switching means in response to the signal outputted from the control switch for instructing deactivation, during charging The second switching means is switched in response to a signal from a preheating switch instructing whether or not to heat the cab, and a signal output from the voltage detection means, a signal output from the current detection means, and the oil depending on the signal output from the temperature detecting means is characterized by comprising a control means for controlling the charging power and heat power of the charging means.

  In the present invention configured as described above, the charging power supplied to the battery from the charging means for charging by the power from the external power source by selectively switching the first switching means and the second switching means by the control means. And heating power supplied from the charging means to the inverter are controlled. The electric motor is driven by the electric power for heat generation, the hydraulic pump is driven by the electric motor, the pressure oil discharged from the hydraulic pump flows into the hydraulic circuit, and the pressure oil generates heat through the valve mechanism. The heated pressure oil is heat-exchanged by the heat exchanging means, and can thereby be heated. In other words, since a part of the power of the charging means can be used as heat generation power, the pressure oil flowing through the hydraulic circuit during charging without a special power circuit for preheating and without using a timer. Can be preheated and heated using the generated heat.

  Further, since the control means controls the power supplied to the battery according to the signal from the voltage detection means for detecting the output voltage of the charging means and the current detection means for detecting the output current of the charging means, Even if power is distributed for heating, a special device for controlling the current so that the voltage does not become an overvoltage with respect to the battery becomes unnecessary. Further, since the control means controls the electric power supplied to the inverter according to the signal from the oil temperature detecting means for detecting the temperature of the pressure oil in the hydraulic circuit, heating with an appropriate oil temperature can be performed.

  The present invention uses a battery charging means to which external electric power is supplied, and can use a part of the electric power as energy for heating. Therefore, without adding a special power circuit for preheating, Further, it is possible to preheat the pressure oil flowing through the hydraulic circuit during charging without using a timer. As a result, the structure can be simplified as compared with the conventional case, and the manufacturing cost can be reduced accordingly. Further, a special device for controlling the current so that the voltage does not become an overvoltage with respect to the battery is not necessary, and this also simplifies the structure. Moreover, heating with an appropriate oil temperature can be performed, and accurate heating performance can be ensured.

  The best mode for carrying out a battery-driven construction machine according to the present invention will be described below with reference to the drawings.

[Configuration of this embodiment]
1 is a side view showing a battery-type hydraulic excavator constituting one embodiment of a battery-driven construction machine according to the present invention, FIG. 2 is a circuit diagram showing a drive circuit provided in this embodiment, and FIG. 3 is shown in FIG. It is a figure which shows the structure of the controller with which a drive circuit is equipped.

  The present embodiment is a battery-type hydraulic excavator in which a front working machine capable of excavation work or the like, that is, a link mechanism is operated by a hydraulic system, and turning and traveling are directly moved by an electric motor, that is, an electric motor. In addition, a three-phase AC electric motor is provided, and an inverter that performs DC-AC conversion from the battery is provided.

  As shown in FIG. 1, a battery-type hydraulic excavator 1 according to this embodiment includes a revolving body 2, a link mechanism 3 that is mounted on the revolving body 2 so as to be rotatable in the vertical direction, and a lower side of the revolving body 2. And a traveling body 4 to be arranged. The link mechanism 3 includes a boom 31 attached to the swing body 2, an arm 32 attached to the tip of the boom 31, a bucket 33 attached to the tip of the arm 32, a boom cylinder 34a, an arm cylinder 34b, and a bucket cylinder 34c. Is included. The traveling body 4 mainly includes a track frame 41, a turning wheel bearing 42 for turning the turning body 2, traveling mechanisms 43L and 43R, and endless track tracks 44L and 44R.

  Among the components included in the drive circuit shown in FIG. 2 provided in the battery-type hydraulic excavator shown in FIG. 1, those other than the external power source, for example, the commercial power source 9, are mounted on the swing body 2. FIG. 2 shows a state where the battery is charged by a commercial power source 9 such as 100V or 200V.

When electric power is supplied from the commercial power supply 9 to the charging means, that is, the charger 22, the electric power of the charger 22 can be supplied to the battery 21 and the inverter 23. Supply of power from the charger 22 to the battery 21 , supply stop, that is, on / off is performed by the first switching means, for example, the contactor 275. Supply of power from the charger 22 to the inverter 23, supply stop, that is, on / off, is performed by the second switching. This is done by means such as contactor 274. The inverter 23 supplies control power to the electric motor, that is, the electric motor 24. The electric motor 24 provides rotational power to a hydraulic pump 251 included in the hydraulic circuit 25.

In the hydraulic circuit 25, the hydraulic pump 251 draws hydraulic oil from the hydraulic oil tank 254 and discharges it to the control valve 252. The control valve 252 controls the hydraulic oil flow rate and supplies the hydraulic oil to an actuator such as a boom cylinder 34 a included in the link mechanism 3. Thereby, the link mechanism 3 is driven and excavation work or the like is performed. The turning and traveling are performed by driving a turning electric motor and a traveling electric motor (not shown) by electric power supplied through the inverter 23 .

  For example, an oil temperature detecting means for detecting the temperature of the discharged pressure oil, for example, an oil temperature sensor 273 and a relief valve 253 is provided on the discharge pipe of the hydraulic pump 251. Valve bodies such as the relief valve 253 and the control valve 252 constitute a valve mechanism that generates heat in the pressure oil discharged from the hydraulic pump 251.

  The downstream side of the relief valve 253 is connected to heat exchange means, that is, a heat exchanger 281 disposed in the cab 28, and the heat of the hydraulic oil is converted into warm air in the cab 28 by the heat exchanger 281. Thus, the inside of the cab 28 can be heated.

  In the cab 28, an operator arranges a control switch 282 for instructing the operation and stoppage of the charger 22, and a preheating switch 283 for instructing whether or not to heat the cab 28 during charging. .

  In the present embodiment, a voltage sensor 271 that detects an output voltage from the charger 22, a current sensor 272 that detects an output current from the charger 22, and an oil temperature sensor that detects the temperature of the pressure oil flowing through the hydraulic circuit 25. The contactors 275 and 274 are appropriately switched in accordance with the signals output from the 273 and the signals output from the control switch 282 and the preheating switch 283 described above to control the charging power and heating power of the charger 22. Control means, that is, a controller 26 is provided.

  As shown in FIG. 3, the controller 26 makes a determination based on the signal S1in output from the control switch 282, and outputs a signal S1out corresponding to the determination result to the charger 22 and the call contactor 275. And a determination unit 262 that performs determination based on the signal S2in output from the preheating switch 283 and outputs a signal S2out corresponding to the determination result to the inverter 23 and the contactor 274.

  The hydraulic pump 251 is driven in consideration of the amount of heat generated by pressure loss in the relief valve 253 of the hydraulic circuit 25, for example, the amount of heat generated that is considered to be approximately equal to the product of the differential pressure between the inlet and outlet of the relief valve 253 and the passing flow rate. The target value Po of the horsepower supplied from the inverter 23 to the electric motor 24 is set, the target value Io of the control current of the charger 22 is set, and the upper limit temperature of the pressure oil flowing through the hydraulic circuit 25, that is, the upper limit value To is set. A target value setter 263 for setting is provided.

  Further, a product of the signal S2out output from the determiner 262 and the target value Po of the horsepower supplied from the inverter 23 is obtained, and a multiplier 264 that outputs a command value P′o, and a command value output from the multiplier 264 An amplifier 265 that divides P′o by a signal Vsen output from the voltage sensor 271 and outputs an addition current ΔIo, an addition current ΔIo output from the amplifier 265, and a target value Io of the control current of the charger 22. And an adder 266 for adding and outputting the final target value I′o.

  Further, the final target value I′o of the control current of the charger 22 output from the adder 266, the signal Vsen of the voltage sensor 271 and the signal Isen of the current sensor 272 are input, and constant current / constant voltage control is performed. A controller 269 that performs the determination, an upper limit value To that is output from the target value setter 263, and a signal Tsen that is output from the temperature sensor 273, and a determiner 268 that outputs a signal Tout corresponding to the result. A multiplier 267 that multiplies the signal output from the controller 269 and the signal Tout output from the determiner 268 and outputs a signal corresponding to the product to the charger 22 is provided.

[Operation of this embodiment]
In the controller 26 described above, as shown in FIG. 3, a signal from the control switch 282, that is, a signal S <b> 1 in corresponding to an instruction to charge the battery 21 is input to the determiner 261. In the determiner 261,
When S1in ≠ 0, S1out = 1
When S1in = 0, S1out = 0
The signal S1out is output to the charger 22 and the contactor 275. The charger 22 receives the signal S1out and enters a standby state when the switch is ON, that is, when S1out = 1. At the same time, the contactor 275 is turned on, and the battery 22 can be energized from the charger 22.

Further, a signal from the preheating switch 283, that is, a signal S2in corresponding to the start of heating is input to the determiner 262. In the determiner 262,
When S2in ≠ 0, S2out = 1
When S2in = 0, S2out = 0
The signal S2out is output to the inverter 23 and the contactor 274. The inverter 23 receives the signal S2out and enters a standby state when the switch is ON, that is, when S2out = 1. At the same time, the contactor 274 is turned on and the electric motor 24 can be energized from the inverter 23.

  In the target value setter 263, as described above, the target value Po of the horsepower supplied from the inverter 23 to the electric motor 24 that drives the hydraulic pump 251, the target value Io of the control current of the charger 22, and the oil flowing through the hydraulic circuit 25 That is, three target values of the upper limit value To of the hydraulic oil temperature are set.

The multiplier 264 multiplies the signal S2out from the determiner 262 and the target horsepower supply value Po. That is, since the signal S2out = 1 when the preheating switch 283 is ON,
S2out × Po = 1 × Po = P′o
The command value P′o = Po is output to the amplifier 265.

  In the amplifier 265, the output voltage of the charger 22 detected by the voltage sensor 271, that is, the signal Vsen is input, and divided by the above-described command value P′o to obtain the addition current ΔIo. This added current ΔIo is the amount of current supplied to the inverter 23 in order to obtain electric power necessary for heat generation for heating. In the adder 266, the addition current ΔIo and the target value Io are added and input to the controller 269 as the final target value I′o.

FIG. 4 is a diagram for explaining constant current / constant voltage control generally performed as charge control, and FIG. 5 is a diagram for explaining control performed by a controller provided in the controller shown in FIG.

  In general constant current / constant voltage control, as shown in FIG. 4, the terminal voltage and current of the battery 21 are measured, and controlled at a constant current until the voltage reaches an upper limit value. Further, after the voltage reaches the upper limit value, constant voltage control is performed to control the current so as to keep the upper limit value of the voltage constant. Normally, the control stops when the current becomes approximately 0A. This control is generally feedback control that maintains the target value while observing the detection voltage and detection current. The reason for performing the constant voltage control is that when the voltage to the battery 21 becomes an overvoltage, the evaporation of the electrolyte starts depending on the battery 21, and the battery 21 may become unusable, or may ignite and explode due to some factor. Because.

In contrast, the controller 269 of the present embodiment performs constant current / constant voltage control shown in FIG. That is, since the final target value I'o such that by adding the ΔIo for heating, the signal output from the controller 269 to the charger 22, that is, the current output from the controller 269 to the charger 22, in FIG. 5 The conventional fine solid line shown is converted into a thick solid line. Upon reaching the constant voltage control region, the current that are controlled to maintain a constant voltage while adding DerutaIo. The charger 22 supplies a current indicated by a thin solid line in FIG. 5 to the battery 21 side, and supplies a current corresponding to the difference between the thick solid line and the thin solid line in FIG. 5 to the inverter 23 side. Further, after the charging is completed, as shown in FIG. 5, the current supplied from the charger 22 to the battery 21 side is substantially zero.

As shown in FIG. 3, the multiplier 267 multiplies the signal output from the controller 269 and the signal Tout output from the determiner 268. The determination unit 268 compares the upper limit value To of the hydraulic oil with the detected temperature output from the oil temperature sensor 273, that is, the signal Tsen. When the signal Tsen has not reached the upper limit value To, Tout = 1 is reached. Sometimes Tout = 0 is output. These are determinations as to whether the temperature of the hydraulic oil has reached the required temperature, that is, whether the required temperature at which the cab 28 can be heated has been reached. As a result of multiplication by the multiplier 267, the preheating control is continued when the hydraulic oil temperature is lower than the upper limit value To, and when the hydraulic oil temperature becomes equal to or higher than the upper limit value To , the constant current / constant voltage control shown in FIG. Stop.

As described above, in this embodiment, the contactor 275 and 274 are simultaneously turned on by the controller 26, whereby the charging power supplied from the charger 22 charged by the power from the commercial power supply 9 to the battery 21, and the charger 22. The power for heating supplied from the inverter to the inverter 23 is controlled. The electric motor 24 is driven by the electric power for heat generation, the hydraulic pump 251 is driven by the electric motor 24, and the pressure oil discharged from the hydraulic pump 251 flows into the hydraulic circuit 25. This pressure oil is used as the relief valve 253, the control valve. Heat is generated through 252 and the like. The heated pressure oil is heat-exchanged by, for example, the heat exchanger 281 in the cab 28, whereby the cab 28 can be heated. That is, since a part of electric power of the charger 22 can be used as heat generation power, the hydraulic circuit 25 flows during charging without adding a special power circuit for preheating and without using a timer. The pressure oil can be preheated and the inside of the cab 28 can be heated using the generated heat. As a result, the structure can be simplified, and the production cost can be reduced accordingly, and heating can be performed quickly at the start.

  Further, the controller 26 controls the power supplied to the battery 21 in accordance with signals from the voltage sensor 271 that detects the output voltage of the charger 22 and the current sensor 272 that detects the output current of the charger 22. Even if power is distributed for heating while charging the battery, a special device for controlling the current so that the voltage does not become an overvoltage with respect to the battery 21 becomes unnecessary. This also simplifies the structure. Further, since the controller 26 controls the electric power supplied to the inverter 23 in accordance with a signal from the oil temperature sensor 273 that detects the temperature of the pressure oil in the hydraulic circuit 25, heating with an appropriate oil temperature can be performed, and the accuracy can be improved. Good heating performance can be secured.

It is a side view which shows the battery-type hydraulic shovel which comprises one Embodiment of the battery drive type construction machine of this invention. It is a circuit diagram which shows the drive circuit with which this embodiment is equipped. FIG. 3 is a diagram illustrating a configuration of a controller provided in the drive circuit illustrated in FIG. 2. It is a figure explaining the constant current and constant voltage control generally implemented as charge control. It is a figure explaining the control implemented with the controller with which the controller shown in FIG. 2 is equipped.

Explanation of symbols

1 Battery-powered excavator (Battery-driven construction machine)
2 Revolving body 21 Battery 22 Charger (charging means)
23 Inverter 24 Electric motor (electric motor)
25 Hydraulic circuit 251 Hydraulic pump 252 Control valve (valve mechanism)
253 Relief valve (valve mechanism)
26 controller (control means)
261 determiner 262 determiner 263 target value setter 264 multiplier 265 amplifier 266 adder 267 multiplier 268 determiner 269 controller 271 voltage sensor (voltage detection means)
272 Current sensor (current detection means)
273 Oil temperature sensor (oil temperature detection means)
274 Contactor (second switching means)
275 Contactor (first switching means)
28 cab 281 heat exchanger (heat exchange means)
282 Control switch 283 Preheating switch 9 Commercial power supply (external power supply)

Claims (1)

A battery, an inverter for controlling battery power, an electric motor driven by output power of the inverter,
A hydraulic circuit including a hydraulic pump driven by the electric motor and a valve mechanism for generating heat in the pressure oil discharged from the hydraulic pump;
In a battery-powered construction machine provided with heat exchange means for exchanging heat of the pressure oil warmed by this hydraulic circuit,
Charging means for charging the battery using power from an external power source;
Voltage detection means for detecting the voltage on the output side of the charging means, current detection means for detecting current on the output side of the charging means, oil temperature detection means for detecting the temperature of the pressure oil in the hydraulic circuit,
A first switching means for controlling supply and stop of power supply from the charging means to the battery; and a second switching means for controlling supply and stop of power supply from the charging means to the inverter ;
The first switching means is switched in response to a signal output from a control switch that instructs operation and stop of the charging means, and in response to a preheat switch signal that indicates whether or not to heat the cab in charging. switches the second switching means, a signal output from said voltage detection means, the signal is outputted from said current detecting means, and in response to the signal outputted from the oil temperature detecting means, a charging power of the charging means A battery-powered construction machine comprising control means for controlling electric power for heat generation.

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