Dump truck

Abstract

A dump truck (1) comprises a vehicle body frame (5) on which front wheels (3) and rear wheels (4) are installed, an electric motor (25) that drives the rear wheels (4), a battery device (26) that is mounted on the vehicle body frame (5) and supplies power to the electric motor (25), and an electrical apparatus that is provided behind the battery device (26) and includes a converter (34). A first refrigerant conduit (45) for refrigerant that cools the battery device (26) and a second refrigerant conduit (54) for refrigerant that cools the electrical apparatus are provided below the battery device (26).

Description

Dump truck

[0001] The present disclosure relates to a dump truck that is suitable for use in transporting crushed stone excavated from, for example, an open-cut mining site, a mine, or the like.

[0002] Generally, in open-cut mining sites, mines, and the like, hydraulic excavators are used to excavate crushed material such as minerals, and large amounts of the excavated material are loaded onto dump trucks for transport to a designated unloading area. Dump trucks are configured to include a vehicle body to which front and rear wheels are attached, and a loading platform (vessel) attached so as to be rotatable up and down around the rear of the vehicle body as a fulcrum.

[0003] Dump trucks are equipped with electric motors as a power source for rotating the left and right drive wheels. Dump trucks are equipped with an engine and a generator driven by the engine, and the electric motor is driven by power from the generator to drive the dump truck. Dump trucks equipped with engines are equipped with a radiator that cools the engine coolant and a radiator that cools the intake air compressed by a turbocharger (Patent Document 1).

[0004] In recent years, dump trucks have been proposed that are equipped with a battery device instead of an engine-driven generator, and that use the power stored in the battery device to drive an electric motor for traveling. The battery device of the dump truck is composed of multiple battery modules to increase the traveling distance. Dump trucks equipped with a battery device are usually equipped with a cooling system that cools the battery device and a cooling system that cools other electrical equipment besides the battery device.

[0005] JP 2017-155660 A

[0006] In general, it is desirable for a battery device to be used at a temperature of about 25°C, and the temperature is strictly controlled using a chiller unit or the like. On the other hand, the temperature of electrical equipment other than the battery device is controlled using a radiator or the like to maintain the temperature at about the same as the outside temperature. Therefore, when operating a dump truck in an area where the outside temperature exceeds 25°C, it is necessary to control the temperature of the battery device to fall within a temperature range lower than the outside temperature, and to control the temperature of electrical equipment other than the battery device to fall within a temperature range at about the same as the outside temperature.

[0007] 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 a dump truck that is capable of cooling a battery device and electrical equipment other than the battery device so that they fall within an appropriate temperature range.

[0008] The present invention provides a dump truck comprising a body frame on which wheels are mounted, an electric motor that drives the wheels, a battery device mounted on the body frame and supplying power to the electric motor, and electrical equipment including a converter that is arranged behind the battery device, wherein a first refrigerant pipe through which a refrigerant that cools the battery device flows and a second refrigerant pipe through which a refrigerant that cools the electrical equipment flows are arranged below the battery device, the body frame is provided with a first tank that stores refrigerant to be supplied to the first refrigerant pipe and a second tank that stores refrigerant to be supplied to the second refrigerant pipe, and the first refrigerant pipe connected to the first tank and the second refrigerant pipe connected to the second tank are arranged below the battery device in two groups spaced apart from each other.

[0009] According to the present invention, by gathering the first refrigerant pipe and the second refrigerant pipe below the battery, the temperature of the refrigerant for the battery that flows through the first refrigerant pipe and the temperature of the refrigerant for the electrical equipment that flows through the second refrigerant pipe can be kept low by utilizing the cooled battery, thereby efficiently cooling the battery and the electrical equipment other than the battery so that they fall within their respective appropriate temperature ranges.

[0010] FIG. 1 is a left side view showing a dump truck to which an embodiment of the present invention is applied. FIG. 2 is a perspective view showing a body frame alone. FIG. 3 is a plan view showing a battery device and electrical equipment mounted on the body frame. FIG. 4 is a front view of a dump truck with a current collector removed, viewed from the front. FIG. 5 is a perspective view of a battery device, a first refrigerant pipe, and a second refrigerant pipe, viewed from below. FIG. 6 is a left side view showing the battery device, electrical equipment, the first refrigerant pipe, the second refrigerant pipe, etc., with the body frame omitted. FIG. 7 is a right side view showing the battery device, electrical equipment, the second refrigerant pipe, etc., with the body frame omitted. FIG. 8 is a bottom view of the battery device, electrical equipment, the first refrigerant pipe, the second refrigerant pipe, etc., viewed from below the body frame. FIG. 9 is a configuration diagram showing a first cooling system that cools the battery device. FIG. 10 is a configuration diagram showing a second cooling system that cools electrical equipment other than the battery device.

[0011] Hereinafter, a detailed description will be given of an embodiment of the present invention, taking a trolley-type dump truck as an example, with reference to the accompanying drawings. In the embodiment, the traveling direction of the dump truck is defined as the front-rear direction, and the direction perpendicular to the traveling direction is defined as the left-right direction.

[0012] 1, a trolley-equipped dump truck 1 travels by supplying power from a trolley overhead line installed in a mine or the like to an electric motor for traveling via a current collector (trolley). The dump truck 1 includes a self-propelled vehicle body 2 having left and right front wheels 3 and left and right rear wheels 4, and a loading platform 19 (described below) mounted on the vehicle body 2 so as to be tiltable (raise and lower). Minerals mined by a hydraulic excavator or the like (not shown) are loaded onto the loading platform 19 and transported. The vehicle body 2 of the dump truck 1 includes a vehicle frame 5, a deck 22, a cab 23, etc. (described below).

[0013] The left and right front wheels 3 are rotatably mounted on the front side of the vehicle body 2 and constitute steered wheels. The front wheels 3 are supported by the vehicle body frame 5 via front-wheel-side suspensions, which dampen vibrations transmitted from the front wheels 3 to the vehicle body 2. The left and right rear wheels 4 are rotatably mounted on the rear side of the vehicle body 2 and are rotationally driven by running devices 24 equipped with electric motors 25 (described later). The running devices 24 for the rear wheels 4 are attached to the vehicle body frame 5 via rear-wheel-side suspensions, which dampen vibrations transmitted from the rear wheels 4 to the vehicle body 2.

[0014] The body frame 5 is a strong support structure that forms the base of the body 2 and extends in the fore-and-aft direction. As shown in Figure 2, the body frame 5 includes a left frame 6, a right frame 7, a front frame 8, a rear frame 9, an upper plate 10, a lower plate 11, etc., which will be described later.

[0015] The left frame 6 is disposed on the left side of the body frame 5. The left frame 6 is configured to include left and right side panels 6A that face each other in the left-right direction, an upper panel 10 that closes the upper ends of the left and right side panels 6A, and a lower panel 11 that connects the lower ends of the left and right side panels 6A, and has a box structure with a rectangular cross section that extends in the front-to-rear direction. The right frame 7 is disposed on the right side of the body frame 5. The right frame 7 is configured to include left and right side panels 7A that face each other in the left-to-right direction, an upper panel 10 that closes the upper ends of the left and right side panels 7A, and a lower panel 11 that connects the lower ends of the left and right side panels 7A, and has a box structure with a rectangular cross section that extends in the front-to-rear direction.

[0016] The left frame 6 and the right frame 7 extend in the front-to-rear direction while facing each other with a gap left and right, and the gap between the left frame 6 and the right frame 7 in the front and rear directions is set larger than the gap at the rear of the body frame 5. A left rear end bracket 6B is provided at the rear end of the left frame 6, and a right rear end bracket 7B is provided at the rear end of the right frame 7, with the left rear end bracket 6B and the right rear end bracket 7B facing each other in the left and right directions.

[0017] The front frame 8 is disposed on the front side of the body frame 5. The front frame 8 has a box structure extending in the left-right direction, including front and rear side plates 8A, an upper plate 10, and a lower plate 11 that face each other in the front-rear direction, and connects the front end of the left frame 6 to the front end of the right frame 7. The rear frame 9 is disposed on the rear side of the body frame 5. The rear frame 9 has a box structure extending in the left-right direction, including front and rear side plates 9A, an upper plate 10, and a lower plate 11 that face each other in the front-rear direction, and connects the rear end of the left frame 6 to the rear end of the right frame 7.

[0018] The upper plate 10 is provided on the upper ends of the left frame 6, right frame 7, front frame 8, and rear frame 9. The upper plate 10 closes the upper ends of the left frame 6, right frame 7, front frame 8, and rear frame 9, and also connects the left frame 6 and the right frame 7. The upper plate 10 is provided with a front opening 10A and a rear opening 10B located between the left frame 6 and the right frame 7.

[0019] The lower plate 11 is provided at the lower ends of the left frame 6, right frame 7, front frame 8, and rear frame 9, facing the upper plate 10 in the vertical direction. The lower plate 11 closes the lower ends of the left frame 6, right frame 7, front frame 8, and rear frame 9, and connects the left frame 6 and the right frame 7. The lower plate 11 is provided with a front opening 11A and a rear opening 11B at positions corresponding to the front opening 10A and rear opening 10B of the upper plate 10.

[0020] The left support pillar 12 and the right support pillar 13 are located forward of the center of the body frame 5 in the longitudinal direction and face each other in the left-right direction. The left support pillar 12 and the right support pillar 13 each have a mountain-shaped hollow box structure. The left support pillar 12 protrudes upward from the upper plate 10 that constitutes the left frame 6, and the right support pillar 13 protrudes upward from the upper plate 10 that constitutes the right frame 7. A deck 22 and the like are attached to the upper ends of the left support pillar 12 and the right support pillar 13.

[0021] The left cylinder bracket 14 and the right cylinder bracket 15 are provided rearward from the midpoint in the fore-and-aft direction of the body frame 5 and face each other in the left-right direction. The left cylinder bracket 14 protrudes downward from the lower plate 11 that constitutes the left frame 6, and the right cylinder bracket 15 protrudes downward from the lower plate 11 that constitutes the right frame 7. A cylinder support shaft 16 extending in the left-right direction is inserted through the lower ends of the left cylinder bracket 14 and the right cylinder bracket 15. The lower ends of hoist cylinders 20, which will be described later, are attached to both left-and-right ends of the cylinder support shaft 16.

[0022] Left and right front brackets 17 are provided near the left front corner where the left frame 6 and the front frame 8 intersect, and near the right front corner where the right frame 7 and the front frame 8 intersect. These left and right front brackets 17 face each other in the left-right direction, sandwiching the front opening 10A of the upper plate 10 therebetween, and left and right front extension plates 28D of the battery frame 27, which will be described later, are attached to them. In addition, left and right rear brackets 18 are provided on the left frame 6 and the right frame 7, located rearward of the left and right front brackets 17. These left and right rear brackets 18 face each other in the left-right direction, sandwiching the front opening 10A of the upper plate 10 therebetween, and left and right rear extension plates 28E of the battery frame 27 are attached to them.

[0023] The loading platform (vessel) 19 is mounted on the body frame 5 so as to be tiltable (raise and lower). The loading platform 19 is formed as a large, bottomed container for carrying crushed material such as minerals mined by a hydraulic excavator or the like. The rear bottom of the loading platform 19 is tiltably connected to the left rear end bracket 6B of the left frame 6 and the right rear end bracket 7B of the right frame 7 via connecting pins 19A. A eaves portion 19B is integrally formed on the front side of the loading platform 19, extending horizontally forward from the top. The eaves portion 19B of the loading platform 19 extends to the front end of the deck 22, covering the cab 23 from above.

[0024] The hoist cylinders 20 are provided in pairs in the left-right direction between the body frame 5 and the loading platform 19 (only the left side is shown). The hoist cylinders 20 are, for example, hydraulic cylinders, and tilt the front side of the loading platform 19 up and down relative to the body frame 5. One end (lower end) of the hoist cylinders 20 is attached to the cylinder support shaft 16, and the other end (upper end) of the hoist cylinders 20 is attached to the underside of the loading platform 19. Therefore, by extending the hoist cylinders 20, the front side (eaves portion 19B side) of the loading platform 19 is lifted upward around the connecting pin 19A, allowing minerals and the like loaded on the loading platform 19 to be discharged rearward.

[0025] The building 21 is provided on the front end side of the body frame 5. The building 21 is formed in a frame shape surrounded by left and right side panels, a front panel (grill), etc., and a battery device 26 and the like are housed inside the building 21. The building 21, together with the left support column 12 and right support column 13 of the body frame 5, also serves to support the deck 22 and the like from below.

[0026] The deck 22 is located forward of the loading platform 19 and is provided above the building 21. The deck 22 is formed in the shape of a rectangular flat plate that is long in the left-right direction, and extends horizontally while being supported from below by the left support pillars 12 and right support pillars 13 of the body frame 5 and the building 21. A cab 23, a control cabinet 38 (described later), and the like are mounted on the deck 22, and the upper surface of the deck 22 forms a flat walkway surface for operators and the like to pass through.

[0027] The cab 23 is provided on the upper left side of the deck 22 and defines a cab for an operator. Inside the cab 23, a driver's seat, a steering wheel, a start switch, an accelerator pedal, a brake pedal, and control levers (none of which are shown) are provided.

[0028] A rear-wheel-side traveling device 24 is provided on the rear side of the body frame 5. The traveling device 24 is attached to the body frame 5 via a rear-wheel-side suspension device. Left and right electric motors 25 for traveling are provided on the traveling device 24, and the rotation of these left and right electric motors 25 is transmitted to the left and right rear wheels 4 via speed reducers (not shown).

[0029] Next, the battery device 26 mounted on the body frame 5 will be described with reference to FIGS. 5 and 6. FIG.

[0030] The battery device 26 is located below the deck 22 and mounted on the front portion of the body frame 5. The battery device 26 stores power to be supplied to electrical devices mounted on the dump truck 1, such as the electric motor 25 for traveling. The battery device 26 is configured to include a multi-stage battery frame 27 and a plurality of battery modules 33. The battery frame 27 has a plurality of support frame bodies stacked in the vertical direction, and is supported by the body frame 5. The plurality of battery modules 33 are individually attached to the support frame bodies of the battery frame 27.

[0031] The battery frame 27 has a first support frame body 28 arranged at the bottom, a second support frame body 29 removably attached above the first support frame body 28, a third support frame body 30 removably attached above the second support frame body 29, and a fourth support frame body 31 removably attached above the third support frame body 30.

[0032] The first support frame 28 includes a rectangular frame body 28A extending in the front-to-rear direction, left and right front legs 28B disposed at the front end of the frame body 28A, and left and right rear legs 28C disposed at the rear end of the frame body 28A. A plurality of battery modules 33 are attached to the frame body 28A in a line in the front-to-rear direction. Front extension plates 28D are provided at vertically intermediate portions of the left and right front legs 28B, respectively, and extend laterally from the front legs 28B. Rear extension plates 28E are provided at vertically intermediate portions of the left and right rear legs 28C, respectively, and extend laterally from the rear legs 28C.

[0033] The frame main body 28A of the first support frame 28 is formed into a rectangular frame shape by a front plate 28F, a rear plate 28G, a left plate 28H, a right plate 28J, a lower plate 28K, and an upper plate 28L. The front plate 28F and the rear plate 28G face each other with a gap in the front-to-rear direction, and the left plate 28H and the right plate 28J face each other with a gap in the left-to-right direction. A frame-shaped lower plate 28K is fixed to the lower ends of the front plate 28F, the rear plate 28G, the left plate 28H, and the right plate 28J. A frame-shaped upper plate 28L is fixed to the upper ends of the front plate 28F, the rear plate 28G, the left plate 28H, and the right plate 28J, and the lower plate 28K and the upper plate 28L face each other in the vertical direction.

[0034] The second support frame 29 is formed in a rectangular frame shape extending in the front-rear direction, similar to the frame main body 28A of the first support frame 28. The second support frame 29 is detachably attached to the first support frame 28 using fasteners such as bolts. A plurality of battery modules 33 are attached to the second support frame 29, lined up in the front-rear direction.

[0035] The third support frame 30 includes a rectangular frame body 30A extending in the front-to-rear direction, left and right front legs 30B disposed at the front end of the frame body 30A, and left and right rear legs 30C disposed at the rear end of the frame body 30A. The lower ends of the left and right front legs 30B are detachably attached to the upper ends of the front legs 28B of the first support frame 28 using fasteners such as bolts, and the lower ends of the left and right rear legs 30C are detachably attached to the upper ends of the rear legs 28C of the first support frame 28 using fasteners such as bolts. As a result, the third support frame 30 is disposed on the second support frame 29, and a plurality of battery modules 33 are attached to the frame body 30A in a line in the front-to-rear direction.

[0036] The fourth support frame 31 includes a rectangular frame body 31A extending in the front-to-rear direction, left and right front legs 31B disposed at the front end of the frame body 31A, and left and right rear legs 31C disposed at the rear end of the frame body 31A. The lower ends of the left and right front legs 31B are detachably attached to the upper ends of the front legs 30B of the third support frame 30 using fasteners such as bolts. The lower ends of the left and right rear legs 31C are detachably attached to the upper ends of the rear legs 30C of the third support frame 30 using fasteners such as bolts. As a result, the fourth support frame 31 is disposed on the third support frame 30, and a plurality of battery modules 33 are attached to the frame body 31A in a line in the front-to-rear direction.

[0037] The refrigerant pipe housing 32 is provided inside the frame body 28A of the first support frame 28. Specifically, the refrigerant pipe housing 32 is configured as a rectangular parallelepiped space surrounded by the front side plate 28F, rear side plate 28G, left side plate 28H, and right side plate 28J that make up the frame body 28A. The refrigerant pipe housing 32 of the battery frame 27 houses a plurality of pipes that make up a first refrigerant pipe 45 (described below) and a plurality of pipes that make up a second refrigerant pipe 54.

[0038] A plurality of pipe insertion holes 28M are formed in a row in the left-right direction on the front side plate 28F of the frame main body 28A. A plurality of pipe insertion holes 28N are formed in a row in the front-rear direction on the left side plate 28H, and a plurality of pipe insertion holes 28P are formed in a row in the front-rear direction on the right side plate 28J. The plurality of pipes constituting the first refrigerant pipe 45 and the plurality of pipes constituting the second refrigerant pipe 54 are attached to the first support frame 28 while being inserted through the pipe insertion holes 28M, 28N, and 28P. As a result, the first refrigerant pipe 45 and the second refrigerant pipe 54 are disposed below the battery device 26 while being fixed to the first support frame 28 of the battery frame 27.

[0039] The battery modules 33 are individually attached to the battery frame 27. Each battery module 33 is made of rechargeable batteries such as lithium-ion batteries and is formed in the shape of a rectangular parallelepiped block extending in the left-right direction. The battery modules 33 supply power to electrical devices such as the electric motor 25 for traveling.

[0040] For example, five battery modules 33 are detachably attached to each of the first support frame 28, the second support frame 29, the third support frame 30, and the fourth support frame 31 using fasteners such as bolts. As a result, a total of 20 battery modules 33 are aggregated into a single battery frame 27, constituting a large-capacity battery device 26. The left and right front extension plates 28D of the battery frame 27 (first support frame 28) are attached to the front brackets 17 of the body frame 5, and the left and right rear extension plates 28E are attached to the rear brackets 18 of the body frame 5. As a result, the battery device 26 is supported by the body frame 5 while being disposed between the left frame 6 and the right frame 7.

[0041] The battery modules 33 generate heat as they charge and discharge power. For this reason, a water jacket (not shown) through which a refrigerant such as cooling water flows is provided inside the battery modules 33. This allows the battery modules 33 to maintain a temperature of approximately 25°C, which is the appropriate temperature for operation. Each battery module 33 is provided with a refrigerant inlet 33A through which the refrigerant flows into the water jacket and a refrigerant outlet 33B through which the refrigerant flows out of the water jacket.

[0042] Electrical devices such as a converter 34, a reactor 35, a hydraulic pump drive motor 36, and a pump drive inverter 37 are arranged behind the battery device 26. The converter 34 is located between the right front wheel 3 and rear wheel 4 and is attached to the right frame 7 of the body frame 5. The converter 34 is a DC / DC converter and converts the voltage of the DC power supplied from the battery device 26 to the electric motor 25 for traveling. The converter 34 has a water jacket (not shown) through which coolant flows, a refrigerant inlet 34A through which the coolant flows in, and a refrigerant outlet 34B through which the coolant flows out (see FIG. 8 ).

[0043] The reactor 35 is located behind the battery device 26 and mounted between the left frame 6 and the right frame 7 of the body frame 5. The reactor 35 is electrically connected between the battery device 26 and the converter 34, and includes an LC filter for removing high-frequency noise, a circuit breaker for protecting the battery device 26, and the like. The reactor 35 has a water jacket (not shown) through which coolant flows, a refrigerant inlet 35A through which the coolant flows in, and a refrigerant outlet 35B through which the coolant flows out.

[0044] The hydraulic pump drive motor 36 is located rearward of the reactor 35 and mounted between the left frame 6 and the right frame 7 of the vehicle body frame 5. The hydraulic pump drive motor 36 is an electric motor that drives a hydraulic pump (not shown) using power from the battery device 26. This causes hydraulic oil to be supplied from the hydraulic pump to hydraulic devices such as the hoist cylinder 20 and the power steering device (not shown). The hydraulic pump drive motor 36 has a water jacket (not shown) through which cooling water flows, a refrigerant inlet 36A through which the cooling water flows in, and a refrigerant outlet 36B through which the cooling water flows out.

[0045] The pump drive inverter 37 is located rearward of the hydraulic pump drive motor 36 and is mounted between the left frame 6 and the right frame 7 of the body frame 5. The pump drive inverter 37 controls the power supplied to the hydraulic pump drive motor 36, and controls the operation of the hydraulic pump drive motor 36. The pump drive inverter 37 has a water jacket (not shown) through which cooling water flows, a refrigerant inlet 37A through which the cooling water flows in, and a refrigerant outlet 37B through which the cooling water flows out.

[0046] The control cabinet 38 is mounted on the upper side of the deck 22, next to the right side of the cab 23. The control cabinet 38 is configured to include an inverter that controls the electric motor 25 for traveling. The hydraulic oil tank 39 is attached to the left frame 6 that constitutes the body frame 5. The hydraulic oil tank 39 is attached to the left frame 6, located between the front wheel 3 and rear wheel 4 on the left side, and stores hydraulic oil to be supplied to hydraulic equipment such as the hoist cylinder 20 mounted on the body frame 5.

[0047] The current collector 40 is provided on a pantograph support 41 mounted on the front end of the body frame 5 (see FIG. 1). The current collector 40 collects electric power from a trolley overhead line (not shown) installed along the travel path of the dump truck 1 in a mine or the like, and supplies the power to the electric motor 25 for traveling, the battery device 26, etc. The current collector 40 has a pantograph 42 provided so as to be extendable and contractible between the pantograph support 41 and the trolley overhead line, and a current collector shoe 42A that comes into sliding contact with the trolley overhead line as the pantograph 42 extends.

[0048] Next, we will explain the first cooling system 43 that cools each battery module 33 of the battery device 26 and the second cooling system 52 that cools the electrical equipment (converter 34, reactor 35, hydraulic pump drive motor 36, pump drive inverter 37) located behind the battery device 26.

[0049] The first cooling system 43 cools the battery device 26 that is configured by a plurality of battery modules 33. As shown in Fig. 9 , the first cooling system 43 includes a first tank 44, a first refrigerant pipe 45, a plurality of cooling water pumps 46, and a chiller unit 47.

[0050] The first tank 44 is located forward of the building 21 and attached to the front end of the body frame 5. The first tank 44 stores cooling water that is supplied to the plurality of battery modules 33 through a first refrigerant pipe 45. The plurality of battery modules 33 are connected to the first tank 44 via the first refrigerant pipe 45. The first refrigerant pipe 45 is configured with, for example, three supply-side pipes 45A, 45C, and 45E and three discharge-side pipes 45B, 45D, and 45F.

[0051] One end of the supply-side pipe 45A is connected to the first tank 44 by a connection part 45G. The other end of the supply-side pipe 45A is connected to the refrigerant inlet ports 33A of the four rearmost battery modules 33 among the multiple battery modules 33 attached to the battery frame 27. One end of the discharge-side pipe 45B is connected to the first tank 44 by a connection part 45H. The other end of the discharge-side pipe 45B is connected to the refrigerant outlet ports 33B of the four rearmost battery modules 33.

[0052] One end of the supply-side pipe 45C is connected to the first tank 44 by a connection 45G. The other end of the supply-side pipe 45C is connected to the refrigerant inlet ports 33A of the eight battery modules 33 that are arranged second and third from the back among the plurality of battery modules 33. One end of the discharge-side pipe 45D is connected to the first tank 44 by a connection 45H. The other end of the discharge-side pipe 45D is connected to the refrigerant outlet ports 33B of the eight battery modules 33 that are arranged second and third from the back among the plurality of battery modules 33. One end of the supply-side pipe 45E is connected to the first tank 44 by a connection 45G. The other end of the supply-side pipe 45E is connected to the refrigerant inlet ports 33A of the eight battery modules 33 that are arranged fourth and fifth from the back among the plurality of battery modules 33. One end of the discharge-side pipe 45F is connected to the first tank 44 by a connection 45H. The other end of the discharge pipe 45F is connected to the refrigerant outlets 33B of the eight battery modules 33 arranged fourth and fifth from the back.

[0053] 6 , supply-side pipes 45A, 45C, and 45E of the first refrigerant pipeline 45 connected to the refrigerant inlets 33A of the battery modules 33 extend above a connection 45G with the first tank 44. Furthermore, discharge-side pipes 45B, 45D, and 45F of the first refrigerant pipeline 45 connected to the refrigerant outlets 33B of the battery modules 33 extend above a connection 45H with the first tank 44.

[0054] A first supply-side bent portion 45J is provided at one end of each of the supply-side pipes 45A, 45C, and 45E connected to the first tank 44, and bent in a crank shape from the first tank 44 toward the lower side of the battery device 26 (FIG. 6 shows the first supply-side bent portions 45J of the supply-side pipes 45A, 45C, and 45E overlapping in the left-right direction). Also, a first discharge-side bent portion 45K is provided at one end of each of the discharge-side pipes 45B, 45D, and 45F connected to the first tank 44, and bent gently from the first tank 44 toward the lower side of the battery device 26 (FIG. 6 shows the first discharge-side bent portions 45K of the discharge-side pipes 45B, 45D, and 45F overlapping in the left-right direction).

[0055] The cooling water pumps 46 are respectively provided at connection portions 45G between the supply-side pipes 45A, 45C, and 45E of the first refrigerant pipeline 45 and the first tank 44. The cooling water pumps 46 are driven by a motor 46A and supply the cooling water stored in the first tank 44 to the cooling water inlets 33A of the battery modules 33 through the supply-side pipes 45A, 45C, and 45E. The cooling water supplied to the battery modules 33 from the cooling water inlets 33A cools the battery modules 33 and then returns to the first tank 44 from the cooling water outlets 33B through the discharge-side pipes 45B, 45D, and 45F of the first refrigerant pipeline 45. The cooling water stored in the first tank 44 is cooled by a chiller unit 47.

[0056] The chiller unit 47 is disposed adjacent to the right side of the building 21 and below the deck 22. As shown in FIG. 9 , the chiller unit 47 includes a compressor 48 driven by a motor 48A, a condenser 49 having a cooling fan 49A, an expansion valve 50, and an evaporator 51. The compressor 48 compresses the refrigerant vaporized by the evaporator 51, and the condenser 49 liquefies the compressed refrigerant by condensing it through heat exchange. The expansion valve 50 reduces the pressure of the high-pressure refrigerant liquefied by the condenser 49 to a state where it can easily evaporate. The evaporator 51 evaporates (vaporizes) the depressurized refrigerant, thereby cooling the cooling water stored in the first tank 44.

[0057] When the dump truck 1 is in operation, the battery device 26 made up of the plurality of battery modules 33 is efficiently cooled by the first cooling system 43 equipped with the chiller unit 47. This makes it possible to maintain the temperature of the battery device 26 within an appropriate temperature range of about 25°C.

[0058] The second cooling system 52 cools the electrical devices arranged behind the battery device 26, i.e., the converter 34, the reactor 35, the hydraulic pump drive motor 36, the pump drive inverter 37, etc. The temperature range in which these electrical devices, such as the converter 34, operate properly is generally set higher than the appropriate temperature range of the battery device 26. As shown in Fig. 10 , the second cooling system 52 includes a second tank 53, a second refrigerant pipe 54, a plurality of cooling water pumps 55, and a radiator 56.

[0059] The second tank 53 is attached to the front end of the body frame 5 adjacent to the right side of the first tank 44. The second tank 53 stores coolant that is supplied to the converter 34, the reactor 35, the hydraulic pump drive motor 36, and the pump drive inverter 37 through a second refrigerant pipe 54. The converter 34, the reactor 35, the hydraulic pump drive motor 36, and the pump drive inverter 37 are each connected to the second tank 53 via the second refrigerant pipe 54. The second refrigerant pipe 54 is composed of, for example, three supply pipes 54A, 54C, and 54E and three discharge pipes 54B, 54D, and 54F.

[0060] One end of the supply-side pipe 54A is connected to the second tank 53 by a connection part 54G, and the other end of the supply-side pipe 54A is connected to the refrigerant inlet 34A of the converter 34. One end of the discharge-side pipe 54B is connected to the second tank 53 by a connection part 54H, and the other end of the discharge-side pipe 54B is connected to the refrigerant outlet 34B of the converter 34.

[0061] One end of the supply-side pipe 54C is connected to the second tank 53 by a connection part 54G, and the other end of the supply-side pipe 54C is connected to the refrigerant inlet 35A of the reactor 35. One end of the discharge-side pipe 54D is connected to the second tank 53 by a connection part 54H, and the other end of the discharge-side pipe 54D is connected to the refrigerant outlet 35B of the reactor 35. One end of the supply-side pipe 54E is connected to the second tank 53 by a connection part 54G, and the other end of the supply-side pipe 54E is connected to the refrigerant inlet 36A of the hydraulic pump drive motor 36 and the refrigerant inlet 37A of the pump drive inverter 37. One end of the discharge-side pipe 54F is connected to the second tank 53 by a connection part 54H, and the other end of the discharge-side pipe 54F is connected to the refrigerant outlet 36B of the hydraulic pump drive motor 36 and the refrigerant outlet 37B of the pump drive inverter 37.

[0062] 7 , the refrigerant inlet 36A of the hydraulic pump drive motor 36 and the refrigerant inlet 37A of the pump drive inverter 37 are positioned higher than a connection 54G between the supply-side pipe 54E and the second tank 53. In addition, the refrigerant outlet 36B of the hydraulic pump drive motor 36 and the refrigerant outlet 37B of the pump drive inverter 37 are positioned higher than a connection 54H between the discharge-side pipe 54F and the second tank 53.

[0063] A second supply-side bent portion 54J is provided at one end of each of the supply-side pipes 54A, 54C, and 54E connected to the second tank 53, and bent in a crank shape from the second tank 53 toward the lower side of the battery device 26 (FIG. 7 shows the second supply-side bent portions 54J of the supply-side pipes 54A, 54C, and 54E overlapping in the left-right direction). Also, a second discharge-side bent portion 54K is provided at one end of each of the discharge-side pipes 54B, 54D, and 54F connected to the second tank 53, and bent gently from the second tank 53 toward the lower side of the battery device 26 (FIG. 7 shows the second discharge-side bent portions 54K of the discharge-side pipes 54B, 54D, and 54F overlapping in the left-right direction).

[0064] Cooling water pumps 55 are provided at connection portions 54G between supply-side pipes 54A, 54C, and 54E of the second refrigerant pipeline 54 and the second tank 53. The cooling water pumps 55 are driven by a motor 55A and supply the cooling water stored in the second tank 53 through supply-side pipes 54A, 54C, and 54E and refrigerant inlet ports 34A, 35A, 36A, and 37A to the converter 34, reactor 35, hydraulic pump drive motor 36, and pump drive inverter 37. The cooling water supplied to the electrical equipment such as the converter 34 cools them and then returns to the second tank 53 through refrigerant outlet ports 34B, 35B, 36B, and 37B and discharge-side pipes 54B, 54D, and 54F. The cooling water stored in the second tank 53 is cooled by a radiator 56.

[0065] The radiators 56 are disposed adjacent to each other on both the left and right sides of the building 21. A chiller unit 47 is disposed on the right radiator 56. The left and right radiators 56 are connected to the second tank 53 via radiator pipes 57, respectively. A circulation pump 58 driven by a motor 58A is provided in the radiator pipe 57. The cooling water stored in the second tank 53 is supplied to the radiator 56 by the circulation pump 58, and is returned to the second tank 53 after heat is dissipated by the radiator 56. In this way, when the dump truck 1 is in operation, the electrical equipment other than the battery device 26 (the converter 34, the reactor 35, the hydraulic pump drive motor 36, and the pump drive inverter 37) is cooled by the second cooling system 52, and the temperatures of these electrical equipment can be maintained within an appropriate temperature range.

[0066] Next, the arrangement of the supply-side pipes 45A, 45C, 45E and discharge-side pipes 45B, 45D, 45F that constitute the first refrigerant pipeline 45, and the arrangement of the supply-side pipes 54A, 54C, 54E and discharge-side pipes 54B, 54D, 54F that constitute the second refrigerant pipeline 54 will be described with reference to Figures 5 to 8.

[0067] Intermediate portions of the supply-side pipes 45A, 45C, 45E and the discharge-side pipes 45B, 45D, 45F of the first refrigerant pipeline 45 and intermediate portions of the supply-side pipes 54A, 54C, 54E and the discharge-side pipes 54B, 54D, 54F of the second refrigerant pipeline 54 are respectively disposed below the battery device 26. Specifically, the intermediate portions of the supply-side pipes 45A, 45C, 45E and the discharge-side pipes 45B, 45D, 45F are inserted through a pipe insertion hole 28M provided in the front side plate 28F and a pipe insertion hole 28N provided in the left side plate 28H of the first support frame 28 that constitutes the battery frame 27. As a result, the supply-side pipes 45A, 45C, 45E and the discharge-side pipes 45B, 45D, 45F are accommodated in the refrigerant pipeline accommodating portion 32 of the first support frame 28 in a horizontally aligned state.

[0068] Meanwhile, intermediate portions of the supply-side pipes 54A, 54C, 54E and the discharge-side pipes 54B, 54D, 54F of the second refrigerant pipeline 54 are inserted through a pipe insertion hole 28M provided in the front side plate 28F and a pipe insertion hole 28P provided in the right side plate 28J of the first support frame 28 that constitutes the battery frame 27. As a result, the supply-side pipes 54A, 54C, 54E and the discharge-side pipes 54B, 54D, 54F are accommodated in the refrigerant pipeline accommodating section 32 of the first support frame 28 in a state where they are arranged in parallel in the horizontal direction.

[0069] In this way, the first refrigerant pipe 45 and the second refrigerant pipe 54 are divided into two groups spaced apart in the left-right direction and arranged below the battery device 26. This allows the cooling water flowing through the first refrigerant pipe 45 and the cooling water flowing through the second refrigerant pipe 54 to be cooled using the battery device 26, which is maintained at a temperature of about 25°C.

[0070] A first supply-side on-off valve 59 is provided adjacent to the cooling water pump 46 at each connection 45G between the supply-side pipes 45A, 45C, 45E of the first refrigerant pipeline 45 and the first tank 44. The first supply-side on-off valve 59 is disposed at the lower end of a first supply-side bent portion 45J provided at the supply-side pipes 45A, 45C, 45E. The first supply-side on-off valve 59 can be switched between an open position, which connects the supply-side pipes 45A, 45C, 45E, and a closed position, which cuts off the supply-side pipes 45A, 45C, 45E, for example, by manually operating an operating lever.

[0071] A first discharge-side on-off valve 60 is provided at each connection 45H between the discharge-side pipes 45B, 45D, and 45F of the first refrigerant line 45 and the first tank 44. The first discharge-side on-off valve 60 is disposed at the lower end of a first discharge-side bent portion 45K provided in the discharge-side pipes 45B, 45D, and 45F. The first discharge-side on-off valve 60 is switched between an open position that connects the discharge-side pipes 45B, 45D, and 45F and a closed position that blocks the discharge-side pipes 45B, 45D, and 45F, for example, by manually operating an operating lever. Note that FIG. 6 shows the multiple first supply-side on-off valves 59 and the first discharge-side on-off valve 60 stacked in the left-right direction.

[0072] A second supply-side on-off valve 61 is provided adjacent to the cooling water pump 55 at each connection 54G between the supply-side pipes 54A, 54C, 54E of the second refrigerant pipeline 54 and the second tank 53. The second supply-side on-off valve 61 is disposed at the lower end of a second supply-side bent portion 54J provided in the supply-side pipes 54A, 54C, 54E. The second supply-side on-off valve 61 can be switched, for example, by an operating lever, between an open position that connects the supply-side pipes 54A, 54C, 54E and a closed position that blocks the supply-side pipes 54A, 54C, 54E.

[0073] A second discharge-side on-off valve 62 is provided at each connection 54H between the discharge-side pipes 54B, 54D, and 54F of the second refrigerant line 54 and the second tank 53. The second discharge-side on-off valve 62 is disposed at the lower end of a second discharge-side bent portion 54K provided on the discharge-side pipes 54B, 54D, and 54F. The second discharge-side on-off valve 62 is switched, for example, by an operating lever, between an open position that connects the discharge-side pipes 54B, 54D, and 54F and a closed position that blocks the discharge-side pipes 54B, 54D, and 54F. Note that FIG. 7 shows the multiple second supply-side on-off valves 61 and the second discharge-side on-off valves 62 stacked in the left-right direction.

[0074] The dump truck 1 according to this embodiment has the configuration described above, and the following describes the operation of transporting minerals mined in a mine using the dump truck 1.

[0075] The dump truck 1 loads minerals mined by a hydraulic excavator onto a loading platform 19 in a loading area, transports the minerals to a dumping area located away from the loading area, and dumps them. When traveling uphill, for example, the dump truck 1 drives a traveling electric motor 25 with power from a trolley overhead line. When traveling on a road without a trolley overhead line, such as a flat road, the dump truck 1 drives the traveling electric motor 25 with power from a battery device 26.

[0076] First, the dump truck 1 loads minerals excavated by a hydraulic excavator (not shown) onto the loading platform 19 in a loading area. The loading area is usually located on a flat road that does not require a large amount of power. Therefore, the electric motor 25 for traveling is driven by power from the battery device 26, and the dump truck 1 travels on the flat road within the loading area.

[0077] When the dump truck 1 travels uphill from the loading area to the soil dumping area, the pantograph 42 of the current collector 40 provided at the front end of the body frame 5 is extended, and the current collector shoe 42A of the pantograph 42 is brought into sliding contact with the trolley wire installed on the uphill road. As a result, the electric motor 25 for traveling is driven by power from the trolley wire, and the dump truck 1 travels uphill toward the soil dumping area.

[0078] When the dump truck 1 reaches the flat soil dumping area, the dump truck 1 travels within the soil dumping area using power from the battery device 26. Then, the dump truck 1 drives a hydraulic pump (not shown) using the hydraulic pump drive motor 36, and extends the hoist cylinder 20 using pressurized oil discharged from the hydraulic pump. This causes the loading platform 19 to tilt about the connecting pin 19A, allowing the minerals loaded on the loading platform 19 to be discharged into the soil dumping area. After discharging the minerals loaded on the loading platform 19 into the soil dumping area, the dump truck 1 travels toward the loading area, and loads new minerals onto the loading platform 19 in the loading area.

[0079] In this way, the dump truck 1 travels between the loading area and the dumping area while appropriately selecting the power from the trolley overhead line and the power from the battery device 26 depending on the road surface on which it is traveling. The dump truck 1 then repeats the operation of transporting the minerals loaded onto the loading platform 19 in the loading area to the dumping area and discharging them into the dumping area.

[0080] When the dump truck 1 is in operation, the battery device 26, which is made up of a plurality of battery modules 33, is cooled by the first cooling system 43. That is, the cooling water pump 46 of the first cooling system 43 is driven, and the cooling water in the first tank 44 is supplied to the refrigerant inlet 33A of the battery module 33 through the supply-side pipes 45A, 45C, and 45E of the first refrigerant pipeline 45. The cooling water supplied to the battery module 33 from the refrigerant inlet 33A cools the battery module 33, and then flows back to the first tank 44 from the refrigerant outlet 33B through the discharge-side pipes 45B, 45D, and 45F of the first refrigerant pipeline 45. The cooling water stored in the first tank 44 is cooled by the chiller unit 47.

[0081] In this way, when the dump truck 1 is in operation, the plurality of battery modules 33 can be efficiently cooled by the first cooling system 43 equipped with the chiller unit 47. As a result, even if the battery modules 33 generate heat by charging and discharging power, the first cooling system 43 can maintain the temperature of the battery equipment 26 within an appropriate temperature range of about 25° C. Therefore, even when the dump truck 1 is in operation in an environment where the outside air temperature exceeds 25° C., for example, the battery equipment 26 is maintained at a temperature lower than the outside air temperature.

[0082] On the other hand, the converter 34, reactor 35, hydraulic pump drive motor 36, and pump drive inverter 37, which are electrical equipment other than the battery device 26, are cooled by a second cooling system 52. That is, a cooling water pump 55 of the second cooling system 52 is driven, and the cooling water in the second tank 53 is supplied from refrigerant inlet ports 34A, 35A, 36A, and 37A through supply-side pipes 54A, 54C, and 54E of a second refrigerant pipeline 54 to the converter 34, reactor 35, hydraulic pump drive motor 36, and pump drive inverter 37. The cooling water supplied to the converter 34, reactor 35, hydraulic pump drive motor 36, and pump drive inverter 37 cools them, and then returns to the second tank 53 from refrigerant outlet ports 34B, 35B, 36B, and 37B through discharge-side pipes 54B, 54D, and 54F. The cooling water stored in the second tank 53 is cooled by a radiator 56 .

[0083] In this way, even if the converter 34, reactor 35, hydraulic pump drive motor 36, and pump drive inverter 37 located behind the battery device 26 generate heat when the dump truck 1 is operating, these electrical devices such as the converter 34 can be cooled by the second cooling system 52.

[0084] In this embodiment, the supply-side pipes 45A, 45C, 45E and the discharge-side pipes 45B, 45D, 45F that constitute the first refrigerant pipeline 45, and the supply-side pipes 54A, 54C, 54E and the discharge-side pipes 54B, 54D, 54F that constitute the second refrigerant pipeline 54, are disposed below the battery 26. As a result, even when the dump truck 1 operates in an environment where the outside air temperature exceeds 25°C, the temperature of the cooling water for the battery 26 flowing through the first refrigerant pipeline 45 and the temperature of the cooling water for the electrical equipment such as the converter 34 flowing through the second refrigerant pipeline 54 can be cooled using the battery 26, which is maintained at a stable temperature of approximately 25°C. As a result, the battery 26 and the electrical equipment such as the converter 34 can be efficiently cooled to within their respective appropriate temperature ranges.

[0085] The first refrigerant pipe 45 connected to the first tank 44 and the second refrigerant pipe 54 connected to the second tank 53 are divided into two groups spaced apart in the left-right direction and arranged below the battery device 26. This allows the first refrigerant pipe 45 and the second refrigerant pipe 54 to be arranged compactly using the small space formed below the battery device 26. Furthermore, by dividing the first refrigerant pipe 45 and the second refrigerant pipe 54 into two groups, the workability of connecting the first refrigerant pipe 45 to the refrigerant inlets 33A and refrigerant outlets 33B of the multiple battery modules 33 that make up the battery device 26 is improved. Similarly, the workability of connecting the second refrigerant pipe 54 to the refrigerant inlets 34A, 35A, 36A, and 37A and refrigerant outlets 34B, 35B, 36B, and 37B of the converter 34, the reactor 35, the hydraulic pump drive motor 36, and the pump drive inverter 37 is improved.

[0086] Next, an operation for replacing parts of the first refrigerant pipe 45, for example, the supply side pipe 45A and the discharge side pipe 45B, when they are damaged will be described.

[0087] One end of the supply-side pipe 45A is connected to the first tank 44. The other end of the supply-side pipe 45A is connected to the refrigerant inlets 33A of the four rearmost battery modules 33 among the multiple battery modules 33 that make up the battery device 26. The other end of the supply-side pipe 45A extends above a connection 45G between one end of the supply-side pipe 45A and the first tank 44. Therefore, if the other end of the supply-side pipe 45A is removed from the refrigerant inlet 33A of the battery module 33, the coolant in the supply-side pipe 45A may flow into the first tank 44 and overflow from the first tank 44.

[0088] In contrast, in this embodiment, a supply-side first on-off valve 59 is provided at a connection 45G between one end of the supply-side pipe 45A and the first tank 44. Therefore, with the supply-side first on-off valve 59 switched to the closed position to shut off the supply-side pipe 45A, the other end of the supply-side pipe 45A is removed from the refrigerant inlet 33A of the battery module 33. This prevents the coolant in the supply-side pipe 45A from flowing into the first tank 44, and improves the ease of replacement of, for example, a damaged supply-side pipe 45A with a new supply-side pipe 45A.

[0089] Similarly, when removing the other end of the discharge-side pipe 45B from the refrigerant outlet 33B of the battery module 33, the first discharge-side on-off valve 60 provided at the connection 45H between one end of the discharge-side pipe 45B and the first tank 44 is switched to the closed position. In this manner, with the discharge-side pipe 45B blocked by the first discharge-side on-off valve 60, the other end of the discharge-side pipe 45B is removed from the refrigerant outlet 33B of the battery module 33. This prevents the coolant in the discharge-side pipe 45B from flowing into the first tank 44, improving the workability when replacing the discharge-side pipe 45B.

[0090] The replacement work for the supply-side pipe 45A and the discharge-side pipe 45B described above is similar to the replacement work for the other supply-side pipes 45C, 45E and discharge-side pipes 45D, 45F that constitute the first refrigerant pipeline 45. Moreover, as shown in Fig. 6, the first supply-side on-off valve 59 is located at the lower end of the first supply-side bent portion 45J provided at one end of the supply-side pipes 45A, 45C, and 45E, and the first discharge-side on-off valve 60 is located at the lower end of the first discharge-side bent portion 45K provided at one end of the discharge-side pipes 45B, 45D, and 45F. Therefore, the first supply-side on-off valve 59 and the first discharge-side on-off valve 60 can be located low above ground, and the work of switching them between the open position and the closed position can be performed from the ground in a stable working position.

[0091] Meanwhile, one end of a supply-side pipe 54E constituting the second refrigerant pipeline 54 is connected to the second tank 53, and the other end of the supply-side pipe 54E is connected to the refrigerant inlet 36A of the hydraulic pump drive motor 36 and the refrigerant inlet 37A of the pump drive inverter 37. The other end of the supply-side pipe 54E is located at a higher position than a connection 54G between one end of the supply-side pipe 54E and the second tank 53. Therefore, if the other end of the supply-side pipe 54E is removed from the refrigerant inlet 36A of the hydraulic pump drive motor 36 and the refrigerant inlet 37A of the pump drive inverter 37, the cooling water in the supply-side pipe 54E may flow into the second tank 53, possibly causing the cooling water to overflow from the second tank 53.

[0092] In contrast, in this embodiment, a second supply-side on-off valve 61 is provided at a connection 54G between one end of the supply-side pipe 54E and the second tank 53. Therefore, with the second supply-side on-off valve 61 switched to the closed position to block the supply-side pipe 54E, the other end of the supply-side pipe 54E is removed from the refrigerant inlet 36A of the hydraulic pump drive motor 36 and the refrigerant inlet 37A of the pump drive inverter 37. This prevents the cooling water in the supply-side pipe 54E from flowing into the second tank 53, and improves the ease of replacement of a damaged supply-side pipe 54E with a new supply-side pipe 54E, for example.

[0093] Similarly, when removing the other end of the discharge-side pipe 54F from the refrigerant outlet 36B of the hydraulic pump drive motor 36 and the refrigerant outlet 37B of the pump drive inverter 37, the second discharge-side on-off valve 62 provided at the connection 54H between one end of the discharge-side pipe 54F and the second tank 53 is switched to the closed position. In this manner, with the discharge-side pipe 54F blocked by the second discharge-side on-off valve 62, the other end of the discharge-side pipe 54F is removed from the refrigerant outlet 36B of the hydraulic pump drive motor 36 and the refrigerant outlet 37B of the pump drive inverter 37. This prevents the coolant in the discharge-side pipe 54F from flowing into the second tank 53, improving the workability when replacing the discharge-side pipe 54F.

[0094] The replacement work for the supply-side pipe 54E and the discharge-side pipe 54F described above is similar to the replacement work for the other supply-side pipes 54A, 54C and discharge-side pipes 54B, 54D that constitute the second refrigerant pipeline 54. Moreover, as shown in Fig. 7, the second supply-side on-off valve 61 is disposed at the lower end of the second supply-side bent portion 54J provided at one end of the supply-side pipes 54A, 54C, 54E, and the second discharge-side on-off valve 62 is disposed at the lower end of the second discharge-side bent portion 54K provided at one end of the discharge-side pipes 54B, 54D, 54F. Therefore, the second supply-side on-off valve 61 and the second discharge-side on-off valve 62 can be disposed at a low position above ground, and the work of switching them between the open position and the closed position can be performed from the ground in a stable working position.

[0095] Thus, in the embodiment, in the dump truck 1 including the body frame 5 to which the front wheels 3 and the rear wheels 4 are attached, the electric motor 25 that drives the rear wheels 4, the battery device 26 that is mounted on the body frame 5 and supplies power to the electric motor 25, and electrical equipment including a converter 34 that is arranged behind the battery device 26, a first refrigerant pipe 45 through which a refrigerant that cools the battery device 26 flows and a second refrigerant pipe 54 through which a refrigerant that cools the electrical equipment flows are arranged below the battery device 26, and the body frame 5 is provided with a first tank 44 that stores the refrigerant to be supplied to the first refrigerant pipe 45 and a second tank 53 that stores the refrigerant to be supplied to the second refrigerant pipe 54, and the first refrigerant pipe 45 connected to the first tank 44 and the second refrigerant pipe 54 connected to the second tank 53 are arranged below the battery device 26 while being spaced apart from each other in two groups.

[0096] With this configuration, the temperature of the cooling water for the battery 26 flowing through the first refrigerant pipe 45 and the temperature of the cooling water for the electrical equipment such as the converter 34 flowing through the second refrigerant pipe 54 can be kept at a stable low temperature by utilizing the cooled battery 26. As a result, the battery 26 and the electrical equipment (the converter 34, the reactor 35, the hydraulic pump drive motor 36, and the pump drive inverter 37) can be efficiently cooled so that their respective temperatures fall within their appropriate temperature ranges.

[0097] Moreover, the first refrigerant pipe 45 and the second refrigerant pipe 54 can be arranged compactly by utilizing the small space formed below the battery device 26. Furthermore, by dividing the first refrigerant pipe 45 and the second refrigerant pipe 54 into two groups, the workability of connecting the first refrigerant pipe 45 to the battery device 26 can be improved. Similarly, the workability of connecting the second refrigerant pipe 54 to electrical devices other than the battery device 26 (the converter 34, the reactor 35, the hydraulic pump drive motor 36, and the pump drive inverter 37) can be improved.

[0098] In this embodiment, a first supply-side on-off valve 59 and a first discharge-side on-off valve 60 that open and close the first refrigerant pipe 45 are provided at connections 45G and 45H between the first tank 44 and the first refrigerant pipe 45, and a second supply-side on-off valve 61 and a second discharge-side on-off valve 62 that open and close the second refrigerant pipe 54 are provided at connections 54G and 54H between the second tank 53 and the second refrigerant pipe 54. With this configuration, the first supply-side on-off valve 59 and the first discharge-side on-off valve 60 can shut off the first refrigerant pipe 45. This prevents the refrigerant in the first refrigerant pipe 45 from overflowing from the first tank 44 when the first refrigerant pipe 45 is detached from the battery device 26. In addition, by blocking the second refrigerant pipeline 54 using the supply side second on-off valve 61 and the discharge side second on-off valve 62, the refrigerant in the second refrigerant pipeline 54 can be prevented from overflowing from the second tank 53 when the second refrigerant pipeline 54 is removed from electrical equipment other than the battery device 26.

[0099] In this embodiment, the first refrigerant pipe 45 has a first supply-side bent portion 45J and a first discharge-side bent portion 45K that bend from the first tank 44 toward the lower side of the battery device 26, the first supply-side on-off valve 59 is disposed at the lower end of the first supply-side bent portion 45J, and the first discharge-side on-off valve 60 is disposed at the lower end of the first discharge-side bent portion 45K. The second refrigerant pipe 54 has a second supply-side bent portion 54J and a second discharge-side bent portion 54K that bend from the second tank 53 toward the lower side of the battery device 26, the second supply-side on-off valve 61 is disposed at the lower end of the second supply-side bent portion 54J, and the second discharge-side on-off valve 62 is disposed at the lower end of the second discharge-side bent portion 54K.

[0100] According to this configuration, the first supply-side on-off valve 59, the first discharge-side on-off valve 60, the second supply-side on-off valve 61, and the second discharge-side on-off valve 62 can be disposed at low positions above ground level. As a result, the operation of connecting and disconnecting the first refrigerant pipe 45 using the first supply-side on-off valve 59 and the first discharge-side on-off valve 60, and the operation of connecting and disconnecting the second refrigerant pipe 54 using the second supply-side on-off valve 61 and the second discharge-side on-off valve 62 can be performed from the ground in a stable working position.

[0101] In the embodiment, the dump truck 1 of trolley specifications equipped with the current collector 40 and the battery device 26 is exemplified. However, the present invention is not limited to this, and can also be applied to a dump truck that does not have the current collector 40, for example.

[0102] DESCRIPTION OF SYMBOLS 1 Dump truck 3 Front wheel 4 Rear wheel 5 Body frame 25 Electric motor 26 Battery device 27 Battery frame 33 Battery module 34 Converter (electrical equipment) 35 Reactor (electrical equipment) 36 Hydraulic pump drive motor (electrical equipment) 37 Pump drive inverter (electrical equipment) 44 First tank 45 First refrigerant pipe 45G, 45H, 54G, 54H Connection portion 45J First supply side bent portion (first bent portion) 45K First discharge side bent portion (first bent portion) 53 Second tank 54 Second refrigerant pipe 54J Second supply side bent portion (second bent portion) 54K Second discharge side bent portion (second bent portion) 59 Supply side first on-off valve (first on-off valve) 60 Discharge side first on-off valve (first on-off valve) 61 Supply side second on-off valve (second on-off valve) 62 Discharge side second on-off valve (second on-off valve)

Claims

1. A dump truck comprising: a body frame to which wheels are attached; an electric motor for driving the wheels; a battery device mounted on the body frame and supplying power to the electric motor; and electrical equipment including a converter arranged at the rear of the battery device; a first refrigerant pipe through which a refrigerant for cooling the battery device flows and a second refrigerant pipe through which a refrigerant for cooling the electrical equipment flows are arranged at the underside of the battery device; the body frame is provided with a first tank for storing refrigerant to be supplied to the first refrigerant pipe and a second tank for storing refrigerant to be supplied to the second refrigerant pipe; and the first refrigerant pipe connected to the first tank and the second refrigerant pipe connected to the second tank are arranged at a distance from each other in two groups arranged at the underside of the battery device.

2. A dump truck as described in claim 1, characterized in that a first on-off valve for opening and closing the first refrigerant pipeline is provided at a connection between the first tank and the first refrigerant pipeline, and a second on-off valve for opening and closing the second refrigerant pipeline is provided at a connection between the second tank and the second refrigerant pipeline.

3. The dump truck described in claim 2, characterized in that the first refrigerant pipe has a first bent portion bent from the first tank toward the lower side of the battery device, and the first on-off valve is arranged at the lower end of the first bent portion, and the second refrigerant pipe has a second bent portion bent from the second tank toward the lower side of the battery device, and the second on-off valve is arranged at the lower end of the second bent portion.

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