Electric construction machine

Abstract

An electric hydraulic shovel (1) comprises a heater core (34) for heating, an electric heater (35) that heats a second heat exchange fluid to be supplied to the heater core (34), and a second reserve tank (39) into which the second heat exchange fluid flows in and from which the second heat exchange fluid flows out. A partition wall (12) for partitioning a first cooling fan (28) and the electric heater (35) from each other is additionally provided, and a first reserve tank (29), into which a first heat exchange fluid for cooling an electric motor (15) and the like flows in and from which the first heat exchange fluid flows out, is disposed on the same side as the first cooling fan (28) with the partition wall (12) as a border. Meanwhile, the second reserve tank (39) is disposed on the opposite side of the first cooling fan (28) with the partition wall (12) as a border.

Description

electric construction machinery

[0001] The present invention relates to an electric construction machine such as a hydraulic excavator that is equipped with an electric motor as a power source.

[0002] Generally, a hydraulic excavator, which is a typical example of construction machinery, comprises a self-propelled lower running body, an upper rotating body that is rotatably mounted on the lower running body via a rotating device, and a working device that is provided on the front side of the upper rotating body and is operated by a hydraulic actuator.

[0003] The hydraulic excavator is equipped with an engine as a prime mover, a radiator that cools the first heat exchange liquid (coolant liquid) that has been heated by cooling the engine, a cooling fan that supplies cooling air to the radiator, and a first reserve tank into and out of which the first heat exchange liquid, whose volume increases and decreases with temperature changes, flows (Patent Document 1).

[0004] Here, in Patent Document 1, the first reserve tank is positioned in a position where it is directly exposed to the cooling air from the cooling fan so that the first heat exchange liquid in the first reserve tank is not affected by the heat of the engine, thereby increasing the cooling efficiency of the first heat exchange liquid.

[0005] In recent years, in order to curb global warming and air pollution, electric hydraulic excavators that use electric motors instead of engines as their power source have been put into practical use. These electric hydraulic excavators supply hydraulic oil (hydraulic fluid) to hydraulic actuators by driving a hydraulic pump with the electric motor. Like hydraulic excavators equipped with engines, these electric hydraulic excavators are equipped with a radiator that cools the electric motor and releases heat from the first heat exchange fluid that has been heated, a cooling fan, and a first reserve tank.

[0006] Some electric hydraulic excavators are equipped with a heating device to improve the working environment of the operator. This heating device includes a heater core for heating, an electric heater that heats a second heat exchange liquid to be supplied to the heater core, and a second reserve tank into and out of which the second heat exchange liquid, whose volume increases and decreases with temperature changes, flows (Patent Document 2).

[0007] Japanese Patent No. 6527287 Japanese Patent Laid-Open No. 2002-61230

[0008] In the case of an engine-driven hydraulic excavator such as that disclosed in Patent Document 1, the cooling efficiency of the first heat exchange liquid by the radiator can be improved by directing the cooling air from the cooling fan toward the first reserve tank. However, an electric hydraulic excavator is also provided with a second reserve tank into which the second heat exchange liquid flows, and the cooling air from the cooling fan also hits the second reserve tank, lowering the temperature of the second heat exchange liquid and reducing the heating efficiency. In particular, small electric hydraulic excavators have limited installation space for equipment, so the cooling fan and the second reserve tank are often located close to each other, raising the problem of a decrease in heating efficiency.

[0009] The present invention has been made in consideration of the problems of the conventional technology described above, and an object of the present invention is to provide an electric construction machine that can efficiently cool the first heat exchange liquid that cools the electric motor without reducing heating efficiency.

[0010] The present invention relates to an electric construction machine having an electric motor as a power source, a radiator that cools a first heat exchange liquid that has been heated by cooling the electric motor, a cooling fan that supplies cooling air to the radiator, and a first reserve tank into which the first heat exchange liquid flows, and further comprising a heater core for heating, an electric heater that heats a second heat exchange liquid to be supplied to the heater core, and a second reserve tank into which the second heat exchange liquid flows, wherein a partition is provided between the cooling fan and the electric heater, and the first reserve tank is located on the same side of the partition as the cooling fan, and the second reserve tank is located on the same side of the partition as the electric heater.

[0011] According to the present invention, the cooling air from the cooling fan can be prevented from hitting the second reserve tank, thereby improving heating efficiency.

[0012] Fig. 4 is a right side view showing an electric hydraulic excavator according to an embodiment. Fig. 5 is a plan view showing an upper rotating body with an exterior cover omitted. Fig. 6 is a plan view showing an enlarged right part of the upper rotating body. Fig. 7 is a right side view showing an enlarged right part of the upper rotating body. Fig. 8 is a front view showing a partition wall, a second reserve tank, etc., as viewed from the direction of arrows V-V in Fig. 4. Fig. 9 is a configuration diagram of a cooling circuit using a first heat exchange liquid. Fig. 10 is a configuration diagram of a heating circuit using a second heat exchange liquid.

[0013] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an electric construction machine according to the present invention will be described in detail below with reference to FIGS. 1 to 7, taking as an example a case where the machine is applied to a small electric hydraulic excavator.

[0014] 1, an electric hydraulic excavator 1, which is a representative example of an electric construction machine, includes a self-propelled crawler-type lower traveling body 2 and an upper rotating body 3 that is rotatably mounted on the lower traveling body 2. A blade device (earth removal device) 4 is provided in front of the lower traveling body 2 so as to be rotatable in the vertical direction, and earth removal (ground leveling) work and the like are performed using this blade device 4. A swing-type working device 5 is provided in front of the upper rotating body 3, and this working device 5 is used to perform work such as excavating earth and sand.

[0015] The upper rotating body 3 is provided with a rotating frame 6 that serves as a support structure. The rotating frame 6 constitutes the base of the upper rotating body 3. The rotating frame 6 is attached to the lower traveling body 2, and a working device 5 is attached to the front side thereof.

[0016] The rotating frame 6 is mounted with a cab 7, a counterweight 8, an exterior cover 9, a bulkhead 12, an electric motor 15, a hydraulic pump 16, a battery device 17, an inverter 20, a charger 21, a radiator 22, a first cooling fan 28, a first reserve tank 29, a hydraulic oil tank 30, an oil cooler 31, a second cooling fan 32, an electric heater 35, a second reserve tank 39, etc., which will be described later.

[0017] The cab 7 is provided on the left side of the revolving frame 6. The interior of the cab 7 is a cab where an operator sits. The cab is provided with a driver's seat where the operator sits, travel levers and pedals that control the travel of the undercarriage 2, and work operation levers that control the operation of the work implements 5 and the like (none of which are shown).

[0018] The counterweight 8 is provided at the rear of the revolving frame 6. The counterweight 8 is a weight for maintaining a weight balance with the working device 5. A power supply cable 19, which will be described later, is detachably connected to the top of the counterweight 8.

[0019] The exterior cover 9 covers the upper rotating body 3 around the cab 7. Specifically, the exterior cover 9 includes a left cover portion (not shown) located on the left side and covering the area between the cab 7 and the counterweight 8, a right front cover portion 10 covering the right side of the cab 7 from a midpoint in the fore-and-aft direction to the front side, and a right rear cover portion 11 covering the right side of the cab 7 from a midpoint in the fore-and-aft direction to the rear side up to the counterweight 8.

[0020] The right front cover portion 10 is provided with an outlet 10A for discharging cooling air at a position facing an oil cooler 31 and a second cooling fan 32 (described later). The right rear cover portion 11 is provided with an outlet 11A for discharging cooling air at a position facing a radiator 22 and a first cooling fan 28 (described later).

[0021] As shown in Figure 2, the partition wall 12 is located on the right side of the revolving frame 6. Specifically, the partition wall 12 is located in the middle of the revolving frame 6 in the front-to-rear direction and is formed as a partition plate extending in the left-right and up-down directions. The partition wall 12 separates an area where an electrical system including an electric motor 15 (described later) is arranged from an area where a hydraulic system including a hydraulic pump 16 and a hydraulic oil tank 30 (described later) is arranged. In this way, the partition wall 12 separates the first cooling fan 28 from the electric heater 35.

[0022] The partition wall 12 separates the right-side space surrounded by the revolving frame 6, counterweight 8, and exterior cover 9 into a rear electrical equipment compartment 13 and a front tank compartment 14. The electrical equipment compartment 13 houses an electric motor 15, a battery device 17, an inverter 20, a charger 21, a radiator 22, a first cooling fan 28, a first reserve tank 29, etc., which will be described later. On the other hand, the tank compartment 14 houses a hydraulic pump 16, a hydraulic oil tank 30, an oil cooler 31, a second cooling fan 32, an electric heater 35, a second reserve tank 39, etc.

[0023] The electric motor 15 constitutes the power source of the electric hydraulic excavator 1. The electric motor 15 is disposed, for example, on the right rear side of the revolving frame 6, and is attached so that the axis of the output shaft extends in the front-to-rear direction. The electric motor 15 rotates the output shaft using power supplied from a battery device 17 (described below), and drives the hydraulic pump 16 connected to this output shaft. In addition, for example, the electric motor 15 is formed as an AC motor. DC power from the battery device 17 is converted to AC power by an inverter 20 and supplied to the electric motor 15.

[0024] The electric motor 15 generates heat by converting electrical energy into thermal energy through resistance. Therefore, the electric motor 15 is provided with a first heat exchange liquid passage (not shown) through which a first heat exchange liquid (coolant liquid) flows to suppress a temperature rise due to heat generation. A first pipe 23 (described later) is connected to this first heat exchange liquid passage.

[0025] The hydraulic pump 16 is attached to the front side of the electric motor 15. When driven by the electric motor 15, the hydraulic pump 16 supplies hydraulic oil from a hydraulic oil tank 30 (described later) to hydraulic cylinders provided in the working device 5 and hydraulic actuators such as hydraulic motors provided in the undercarriage 2. The hydraulic pump 16 is connected to the output shaft of the electric motor 15.

[0026] The battery device 17 stores electric power to be supplied to the electric motor 15. The battery device 17 is mounted on the revolving frame 6, located below the rear of the cab 7. The battery device 17 is connected to an external power source (not shown), such as a generator or a commercial power source, via a power supply connector 18 and a power supply cable 19. The battery device 17 is also connected to the electric motor 15 via an inverter 20 and the like. In a charging mode, the power supply cable 19 is connected to the power supply connector 18, and electric power from the external power source is converted into DC power and charged in the battery device 17. In an internal power mode, DC power from the battery device 17 is converted into AC power by the inverter 20 and supplied to the electric motor 15. In an external power mode, electric power from the external power source is similarly converted by the inverter 20 and supplied to the electric motor 15, with surplus electric power being supplied to the battery device 17.

[0027] The inverter 20 is located behind the partition wall 12 and above the electric motor 15. The inverter 20 converts DC power supplied from the battery device 17 into AC power and supplies it to the electric motor 15. The inverter 20 generates heat due to the load (resistance) generated when switching power. For this reason, the inverter 20, like the electric motor 15, has a first heat exchange liquid passage (not shown) through which a first heat exchange liquid flows. A first pipe 23 is connected to this first heat exchange liquid passage, following the electric motor 15.

[0028] When connected to an external power source, the charger 21 converts AC power from the external power source into DC power and supplies it to the battery device 17. The charger 21 is electrically connected to the battery device 17 via a switch (not shown). A power supply cable 19 from the external power source can be connected to the charger 21. The charger 21 generates heat due to the load (resistance) generated when switching power (DC, AC). For this reason, the charger 21, like the inverter 20, has a first heat exchange liquid passage (not shown) through which a first heat exchange liquid flows. A second pipe 25 is connected to this first heat exchange liquid passage.

[0029] The radiator 22 is a heat exchanger that cools a first heat exchange liquid that cools electrical equipment such as the electric motor 15, the inverter 20, and the charger 21. In other words, the radiator 22 cools the first heat exchange liquid that has been heated by cooling the electric motor 15 and other components. The radiator 22 is provided at a rear side of the revolving frame 6, near the center on the right side, and extends in the front-to-rear and up-to-down directions. The radiator 22 is also disposed between the electric motor 15 and the battery device 17. The radiator 22 lowers the temperature of the first heat exchange liquid by releasing heat from the first heat exchange liquid flowing through a plurality of narrow tubes into cooling air generated by a first cooling fan 28, which will be described later. A first pipe 23, a second pipe 25, and a return pipe 27, which will be described later, are connected to the radiator 22.

[0030] Furthermore, a first reserve tank 29 (described later) is connected to the radiator 22. This allows the first heat exchange liquid, whose volume increases or decreases with temperature changes, to flow in and out of the first reserve tank 29, thereby allowing the volume of the first heat exchange liquid to change.

[0031] 6 , the first pipe 23 is connected to the radiator 22. A first pump 24 is provided on the upstream side (radiator 22 side) of the first pipe 23. The first pipe 23 passes through a first heat exchange fluid passage of the electric motor 15 and is connected at its downstream side to a first heat exchange fluid passage of the inverter 20. The first pipe 23 is a pipe that supplies the first heat exchange fluid to the electric motor 15 and the inverter 20.

[0032] The second pipe 25 is connected to the radiator 22 in the same manner as the first pipe 23. A second pump 26 is provided on the upstream side (radiator 22 side) of this second pipe 25. The second pipe 25 passes through a first heat exchange liquid passage of the charger 21 and is connected on the downstream side to a return pipe 27 described below. The second pipe 25 is a pipe that supplies the first heat exchange liquid to the charger 21. Note that the second pipe 25 may be eliminated, and the first heat exchange liquid may be supplied to the electric motor 15, the inverter 20, and the charger 21 only through the first pipe 23.

[0033] The return pipe 27 is connected at its upstream side to the first heat exchange fluid passage of the inverter 20, and at its downstream side to the radiator 22. The return pipe 27 is a pipe that returns the first heat exchange fluid, which has passed through the electric motor 15, the inverter 20, and the charger 21 and has increased in temperature, to the radiator 22.

[0034] 3 and 4 , a first cooling fan 28 serving as a cooling fan is provided above the electric motor 15 and facing the right side of the radiator 22. When rotated by the fan motor, the first cooling fan 28 draws in outside air as cooling air through an air intake port in the left cover portion of the exterior cover 9, circulates the air around the battery device 17, and passes it through the radiator 22. The cooling air that has passed through the radiator 22 passes through the electrical equipment compartment 13 and is discharged to the outside through an outlet port 11A in the right rear cover portion 11 of the exterior cover 9. Note that a suction-type fan that draws in outside air through an air intake port in the right rear cover portion and supplies it to the radiator as cooling air may also be used as the first cooling fan.

[0035] The first reserve tank 29 is provided in the electrical equipment compartment 13. The first reserve tank 29 is connected to the upper part of the radiator 22 via a hose 29A. The first reserve tank 29 is formed, for example, as a container made of a translucent resin material so that the interior can be seen through and the liquid level can be visually observed. The first reserve tank 29 receives and discharges the first heat exchange liquid, whose volume increases or decreases with temperature changes. Specifically, when the temperature of the first heat exchange liquid increases and the volume of the first heat exchange liquid increases, the first reserve tank 29 receives the overflowing first heat exchange liquid from the radiator 22. On the other hand, when the temperature of the first heat exchange liquid decreases and the volume of the first heat exchange liquid decreases, the first reserve tank 29 returns the reduced first heat exchange liquid to the radiator 22.

[0036] Here, the first reserve tank 29 is provided between the first cooling fan 28 and a right rear cover portion 11 (exhaust port 11A) of the exterior cover 9, which will be described later. In other words, the first reserve tank 29 is located rearward of the partition wall 12, on the side of the first cooling fan 28 that is exposed to the cooling air that has passed through the radiator 22 and flowed into the electrical equipment compartment 13. Therefore, the first reserve tank 29 is positioned so as to overlap the first cooling fan 28 in the flow direction of the cooling air generated by the first cooling fan 28. As a result, when the first cooling fan 28 is rotating, the cooling air generated by the first cooling fan 28 is exposed to the first reserve tank 29, thereby keeping the temperature of the first heat exchange liquid in the first reserve tank 29 low.

[0037] The hydraulic oil tank 30 is located on the right front side of the revolving frame 6. The hydraulic oil tank 30 stores hydraulic oil to be supplied to various hydraulic actuators and is connected to the hydraulic pump 16, etc. The hydraulic oil tank 30 is formed as a box-shaped metal container. The hydraulic oil tank 30 is located forward of the partition wall 12, and a rear surface 30A of the hydraulic oil tank 30 faces the partition wall 12 with a gap between them. In other words, the hydraulic oil tank 30 is located in the tank chamber 14 located in front of the electrical equipment room 13, with the partition wall 12 in between.

[0038] The hydraulic oil tank 30 is heated by the hydraulic pump 16 and the hydraulic actuator returning the heated hydraulic oil to the hydraulic oil tank 30. The heat generated by the hydraulic oil tank 30 is transferred to a second reserve tank 39 (described below) located nearby.

[0039] The oil cooler 31 is a heat exchanger that cools the hydraulic oil whose temperature has been increased by the hydraulic pump 16 and the hydraulic actuator. The oil cooler 31 is located in the tank chamber 14 and provided on the right side of the hydraulic oil tank 30 so as to face the right front cover portion 10 (outlet port 10A) of the exterior cover 9.

[0040] The second cooling fan 32 is provided to the right of the oil cooler 31, i.e., between the oil cooler 31 and the right front cover portion 10 (exhaust port 10A). The second cooling fan 32 is rotated by a fan motor (not shown) to generate cooling air from the oil cooler 31 toward the right front cover portion 10. The cooling air that has passed through the oil cooler 31 is then discharged to the outside through the exhaust port 10A. This allows the second cooling fan 32 to supply (blow) cooling air to the oil cooler 31.

[0041] The heating device 33 supplies warm air into the cab 7 to improve the working environment for the operator. The heating device 33 includes a heater core 34, an electric heater 35, and a second reserve tank 39.

[0042] The heater core 34 is provided as part of the indoor unit inside the cab 7. The heater core 34 is connected to an electric heater 35 via circulation paths 36 and 38 (described later). The heater core 34 circulates a second heat exchange liquid heated by the electric heater 35 through a plurality of thin tubes, thereby heating the air blown into the cab 7 from a blower fan (not shown) with the heat of the second heat exchange liquid. Here, the second heat exchange liquid may be, for example, an aqueous solution of water mixed with an antiseptic, an anti-rust agent, or the like, or an oil liquid.

[0043] 3 and 4, the electric heater 35 is provided in the tank chamber 14. More specifically, as shown in Fig. 5, the electric heater 35 is attached to the front surface of the partition wall 12 at the rear side of the hydraulic oil tank 30. When power is supplied to the electric heater 35, the electric heater 35 heats the second heat exchange fluid to be supplied to the heater core 34.

[0044] The circulation path 36 connects the heater core 34 and the electric heater 35, and has a pump 37 on the upstream side. In the circulation path 36, the second heat exchange liquid whose temperature has been lowered by heat exchange in the heater core 34 flows toward the electric heater 35.

[0045] Similarly to the circulation path 36, the circulation path 38 connects the electric heater 35 and the heater core 34. In the circulation path 38, the second heat exchange liquid heated by the electric heater 35 flows toward the heater core 34.

[0046] The second reserve tank 39 is disposed in the tank chamber 14 on the opposite side of the partition wall 12 from the first cooling fan 28. The second reserve tank 39 is connected to the circulation path 36 upstream of the pump 37 via an outlet pipe 40 and to the circulation path 38 via an inlet pipe 41. The second reserve tank 39 is formed, for example, as a container made of a translucent resin material so that the interior can be seen and the liquid level can be visually observed. The second reserve tank 39 receives and discharges the second heat exchange liquid, whose volume changes with temperature. Specifically, when the temperature of the second heat exchange liquid increases and the volume of the second heat exchange liquid increases, the second reserve tank 39 receives the overflowing second heat exchange liquid from the heating device 33. On the other hand, when the temperature of the second heat exchange liquid decreases and the volume of the second heat exchange liquid decreases, the second reserve tank 39 returns the reduced second heat exchange liquid to the heating device 33.

[0047] Regarding the detailed location of the second reserve tank 39, a gap large enough to accommodate the second reserve tank 39 is formed between the partition wall 12 and the rear surface 30A of the hydraulic oil tank 30. The second reserve tank 39 is positioned to the right (outside) of the rear side of the hydraulic oil tank 30. The second reserve tank 39 is positioned forward of the partition wall 12 and rearward of the rear surface 30A of the hydraulic oil tank 30, i.e., between the partition wall 12 and the rear surface 30A of the hydraulic oil tank 30. This allows the second reserve tank 39 to be positioned close enough to the hydraulic oil tank 30 to transfer heat thereto. Therefore, the second reserve tank 39 can warm the second heat exchange fluid therein by the heat from the hydraulic oil tank 30 before the electric heater 35 heats it up.

[0048] Furthermore, the second reserve tank 39 is disposed in the tank chamber 14 on the opposite side of the partition wall 12 from the first cooling fan 28. This prevents the cooling air from the first cooling fan 28 from hitting the second reserve tank 39, thereby preventing the temperature of the second heat exchange liquid from dropping. Therefore, the second heat exchange liquid in the second reserve tank 39 can be warmed while suppressing a drop in temperature.

[0049] The electric hydraulic excavator 1 according to this embodiment has the above-described configuration, and its operation will now be described.

[0050] When performing excavation work or the like using the electric hydraulic excavator 1, the operator sits in the cab 7 and starts the electric motor 15 to drive the hydraulic pump 16. In this state, the operator operates the travel levers and pedals to travel to the work site using the undercarriage 2. Once the electric hydraulic excavator 1 has been moved to the work site, the operator can operate the work control levers to rotate the upper rotating body 3 while performing excavation work of earth and sand using the work device 5.

[0051] During operation of the electric hydraulic excavator 1, the electric motor 15, the inverter 20, and the charger 21 generate heat, and it is therefore necessary to suppress temperature increases in the electric motor 15, the inverter 20, and the charger 21. Therefore, by circulating the first heat exchange liquid cooled by the radiator 22 through the first heat exchange liquid passages of the electric motor 15, the inverter 20, and the charger 21, it is possible to suppress these temperature increases by the first heat exchange liquid. Furthermore, the first heat exchange liquid whose temperature has increased after passing through the electric motor 15, the inverter 20, and the charger 21 is returned to the radiator 22 and cooled. Meanwhile, when the temperature of the first heat exchange liquid changes, the volume of the first heat exchange liquid increases or decreases. This increase or decrease in the volume of the first heat exchange liquid can be absorbed by the first reserve tank 29.

[0052] Furthermore, during work in winter, a heating device 33 is used to raise the temperature inside the cab 7. By operating a switch (not shown) inside the cab 7, the heating device 33 can supply second heat exchange liquid heated by an electric heater 35 to the heater core 34. The heating device 33 also blows air generated by a blower fan through the heater core 34 and into the cab 7, thereby warming the inside of the cab 7 with warm air.

[0053] Thus, according to this embodiment, the electric hydraulic excavator 1 is equipped with a heater core 34 for heating, an electric heater 35 that heats the second heat exchange liquid to be supplied to the heater core 34, and a second reserve tank 39 into and out of which the second heat exchange liquid flows. In addition, a partition wall 12 is provided to separate the first cooling fan 28 and the electric heater 35, and the first reserve tank 29 is disposed on the same side as the first cooling fan 28 with respect to the partition wall 12. On the other hand, the second reserve tank 39 is disposed on the same side as the electric heater 35 with respect to the partition wall 12.

[0054] Therefore, the temperature of the first heat exchange liquid in the first reserve tank 29 can be kept low by the cooling air generated by the rotation of the first cooling fan 28. This allows the cooled first heat exchange liquid to be returned from the first reserve tank 29 to the radiator 22, improving the cooling efficiency of the electric motor 15, the inverter 20, and the charger 21.

[0055] Moreover, in this embodiment, the second reserve tank 39 is disposed on the same side as the electric heater 35 across the partition wall 12, in other words, on the opposite side from the first cooling fan 28, so that the cooling air from the first cooling fan 28 is not directed toward the second reserve tank 39. This makes it possible to suppress a decrease in the temperature of the second heat exchange liquid in the second reserve tank 39. As a result, uncooled second heat exchange liquid can be returned from the second reserve tank 39 to the heater core 34 side, thereby improving heating efficiency.

[0056] The electric hydraulic excavator 1 also includes an electrical equipment room 13 in which the electric motor 15 and the first cooling fan 28 are disposed, and a tank room 14 in which a hydraulic oil tank 30 for storing hydraulic oil and a second reserve tank 39 are disposed. The partition wall 12 separates the electrical equipment room 13 from the tank room 14. Therefore, the partition wall 12 can separate the first cooling fan 28 on the electrical equipment room 13 side from the second reserve tank 39 on the tank room 14 side. As a result, the partition wall 12 can suppress a decrease in the temperature of the second heat exchange liquid in the second reserve tank 39, thereby further improving heating efficiency.

[0057] Furthermore, the first reserve tank 29 is disposed so as to overlap the first cooling fan 28 in the flow direction of the cooling air generated by the first cooling fan 28. This allows the cooling air generated by the first cooling fan 28 to be directed toward the first reserve tank 29, and the temperature of the first heat exchange liquid in the first reserve tank 29 can be kept low.

[0058] Furthermore, the second reserve tank 39 is disposed between the partition wall 12 and the hydraulic oil tank 30. In other words, the second reserve tank 39 is disposed close enough to the hydraulic oil tank 30 that the heat from the hydraulic oil tank 30 can be transferred to the second reserve tank 39. Therefore, the second heat exchange liquid in the second reserve tank 39 can be heated by the heat from the hydraulic oil tank 30 before it is heated by the electric heater 35, thereby improving heating efficiency and saving power.

[0059] In the embodiment, an electric hydraulic excavator 1 equipped with a crawler-type undercarriage 2 is exemplified. However, the present invention is not limited to this, and can be applied to other electric construction machines, such as an electric hydraulic excavator equipped with a wheel-type undercarriage.

[0060] REFERENCE SIGNS LIST 1 Electric hydraulic excavator (electric construction machine) 12 Bulkhead 13 Electrical equipment room 14 Tank room 15 Electric motor 22 Radiator 28 First cooling fan (cooling fan) 29 First reserve tank 30 Hydraulic oil tank 34 Heater core 35 Electric heater 39 Second reserve tank

Claims

1. An electric motor as a power source; a radiator that cools the first heat exchange liquid that has been heated by cooling the electric motor; a first cooling fan that supplies cooling air to the radiator; a first reserve tank into which the first heat exchange liquid flows and into which the first heat exchange liquid flows; a hydraulic pump driven by the electric motor; a hydraulic oil tank connected to the hydraulic pump and configured to store hydraulic oil; In an electric construction machine equipped with A heater core for heating, an electric heater for heating a second heat exchange liquid to be supplied to the heater core; a second reserve tank into which the second heat exchange liquid flows; an oil cooler that cools the hydraulic oil whose temperature has been increased by the hydraulic pump; A second cooling fan that supplies cooling air to the oil cooler; an electrical equipment room in which the electric motor, the radiator, the first cooling fan, and the first reserve tank are disposed; a tank chamber in which the hydraulic oil tank, the oil cooler, the second cooling fan, the electric heater, and the second reserve tank are disposed; Equipped with An electric construction machine characterized in that a partition is provided to separate the electrical equipment room and the tank room.

2. The electric construction machine according to claim 1, an exterior cover that surrounds the electrical equipment chamber and the tank chamber; The exterior cover is a first exhaust port for exhausting cooling air generated by the first cooling fan; a second exhaust port for exhausting the cooling air generated by the second cooling fan; having the first reserve tank is disposed between the first cooling fan and the first exhaust port, 2. An electric construction machine comprising: a hydraulic oil tank; a second reserve tank disposed between the partition wall and the hydraulic oil tank;

3. The electric construction machine according to claim 1, The electric construction machine, characterized in that the second reserve tank is disposed inside the tank chamber and above the hydraulic oil tank, the oil cooler, and the electric heater.

4. The electric construction machine according to claim 2, the second reserve tank is disposed between the partition wall and a rear surface of the hydraulic oil tank, The electric construction machine, characterized in that the oil cooler and the second cooling fan are disposed on the right side of the hydraulic oil tank, between the hydraulic oil tank and the second outlet.