Electric tractor

Abstract

This electric tractor comprises: a traveling device that is driven by a first motor (11); a transmission unit that transmits the driving force of a second motor (12) to a work device; a hydraulic pump that is driven by the second motor (12); and a cooling path (J1) through which cooling liquid circulates. The cooling path (J1) includes: a radiator (38) that cools the cooling liquid; a first path (P1) through which the cooling liquid flows from the radiator (38) toward the first motor (11); a second path (P2) through which the cooling liquid flows from the first motor (11) toward the second motor (12); and a third path (P3) through which the cooling liquid flows from the second motor (12) toward the radiator (38).

Description

electric tractor

[0001] The present invention relates to an electric tractor.

[0002] The work vehicle described in Patent Document 1 (referred to as a "tractor" in Patent Document 1) is equipped with an engine and a traveling device (referred to as "front wheels" and "rear wheels" in Patent Document 1) driven by the engine. The engine is housed in a bonnet (referred to as an "engine bonnet" in Patent Document 1).

[0003] Japanese Patent Application Publication No. 2018-69926

[0004] [1] In the work vehicle described in Patent Document 1, a battery and a motor may be provided instead of the engine, allowing the vehicle to travel without emitting exhaust gases.

[0005] However, when a work vehicle is equipped with a traveling device and a working device (such as a rotary tiller), the power (horsepower) required to drive the traveling device and the working device is relatively high, and therefore, a configuration in which the traveling device and the working device are driven by a single motor as a power source can be expected to result in a power shortage.

[0006] An object of the present invention is to provide an electric tractor that can suitably drive a traveling device and a working device and has good traveling performance.

[0007] [2] An object of the present invention is to provide an electric tractor that can suitably drive the traveling device and the working device and has good working performance.

[0008] [3] In the work vehicle described in Patent Document 1, a battery and a motor may be provided instead of the engine, allowing the vehicle to travel without emitting exhaust gases.

[0009] Furthermore, in this configuration, a cooling path through which the coolant circulates may be provided, and the cooling path may include a motor, a battery, and a radiator that cools the coolant.

[0010] However, in this configuration, if the coolant that has passed through the radiator passes through the battery first, the motor will be relatively hard to cool, and conversely, if the coolant that has passed through the radiator passes through the motor first, the battery will be relatively hard to cool.

[0011] An object of the present invention is to provide an electric tractor in which the motor and battery are cooled effectively.

[0012] [1] The solution to problem [1] is as follows: The present invention is characterized in that it comprises a battery, a first motor and a second motor driven by power supplied from the battery, a traveling device driven by the first motor, a transmission unit that transmits the driving force of the second motor to a working device, a hydraulic pump driven by the second motor, and a cooling path through which a coolant circulates, the cooling path having a radiator that cools the coolant, a first path through which the coolant flows from the radiator to the first motor, a second path through which the coolant flows from the first motor to the second motor, and a third path through which the coolant flows from the second motor to the radiator.

[0013] According to this configuration, the first motor is the power source for the travel device, and the second motor is the power source for the work device. This makes it easier to reliably obtain the power (horsepower) required to drive the travel device and the work device in an optimal manner, compared to when a single motor is used as a power source to drive the travel device and the work device.

[0014] Furthermore, with this configuration, the coolant that has passed through the radiator passes through the first motor first, out of the first and second motors, so the first motor is cooled preferentially, preventing the first motor from becoming too hot and resulting in a decrease in driving performance.

[0015] That is, with this configuration, it is possible to realize an electric tractor that can suitably drive the traveling device and the working device and has good traveling performance.

[0016] Furthermore, in the present invention, it is preferable that a first inverter be provided for converting DC power from the battery into AC power and supplying the AC power to the first motor, and that the first inverter be included in the first path.

[0017] With this configuration, the coolant that has passed through the radiator passes through the first inverter first, out of the first inverter and the second motor. This allows the first inverter to be cooled preferentially. This prevents the first inverter from becoming too hot, which would otherwise cause a decrease in driving performance.

[0018] Furthermore, in the present invention, it is preferable that a second inverter be provided for converting DC power from the battery into AC power and supplying the AC power to the second motor, and that the second inverter be included in the third path.

[0019] With this configuration, the coolant that has passed through the radiator passes through the first motor first, out of the first motor and the second inverter. This allows the first motor to be cooled preferentially. This prevents the first motor from becoming too hot, which would otherwise cause a decrease in driving performance.

[0020] Furthermore, in the present invention, it is preferable that at least a portion of the first path is located below the battery.

[0021] For example, in a configuration in which the battery is supported by a frame or the like, and the frame or the like is supported by a traveling device, there may be a space below the battery in which components can be placed.

[0022] According to this configuration, at least a portion of the first path is disposed in the space, which allows the space to be used effectively.

[0023] Furthermore, in the present invention, it is preferable that at least a portion of the third path is located to the left or right of the battery.

[0024] According to this configuration, at least a portion of the third path can be easily supported (directly or indirectly) by the side wall of the battery, which makes it easier to stably support the third path.

[0025] Furthermore, in the present invention, it is preferable that the circulation direction of the cooling liquid is changeable.

[0026] With this configuration, an electric tractor can be realized that can switch between a state in which the first motor is cooled preferentially and a state in which the second motor is cooled preferentially, out of the first and second motors.

[0027] [2] The solution to problem [2] is as follows: The present invention is characterized in that it comprises a battery, a first motor and a second motor driven by electric power supplied from the battery, a traveling device driven by the first motor, a transmission unit that transmits the driving force of the second motor to a working device, a hydraulic pump driven by the second motor, and a cooling path through which a coolant circulates, the cooling path having a radiator that cools the coolant, a first path through which the coolant flows from the first motor to the radiator, a second path through which the coolant flows from the second motor to the first motor, and a third path through which the coolant flows from the radiator to the second motor.

[0028] According to this configuration, the first motor is the power source for the travel device, and the second motor is the power source for the work device. This makes it easier to reliably obtain the power (horsepower) required to drive the travel device and the work device in an optimal manner, compared to when a single motor is used as a power source to drive the travel device and the work device.

[0029] Furthermore, with this configuration, the coolant that has passed through the radiator passes through the second motor first, out of the first and second motors, so the second motor is cooled preferentially, preventing the second motor from becoming too hot and resulting in a decrease in operating performance.

[0030] That is, with this configuration, it is possible to realize an electric tractor that can drive the traveling device and the working device in an optimal manner and has good working performance.

[0031] Furthermore, in the present invention, it is preferable that a first inverter be provided for converting DC power from the battery into AC power and supplying the AC power to the first motor, and that the first inverter be included in the first path.

[0032] With this configuration, the coolant that has passed through the radiator passes through the second motor first, out of the first inverter and the second motor, which gives priority to cooling the second motor, thereby preventing the second motor from becoming too hot and resulting in a decrease in operating performance.

[0033] Furthermore, in the present invention, it is preferable that a second inverter be provided for converting DC power from the battery into AC power and supplying the AC power to the second motor, and that the second inverter be included in the third path.

[0034] With this configuration, the coolant that has passed through the radiator passes through the second inverter first, out of the first motor and the second inverter, so that the second inverter is cooled preferentially, thereby preventing the second inverter from becoming too hot and causing a decrease in operating performance.

[0035] Furthermore, in the present invention, it is preferable that at least a portion of the first path is located below the battery.

[0036] For example, in a configuration in which the battery is supported by a frame or the like, and the frame or the like is supported by a traveling device, there may be a space below the battery in which components can be placed.

[0037] According to this configuration, at least a portion of the first path is disposed in the space, which allows the space to be used effectively.

[0038] Furthermore, in the present invention, it is preferable that at least a portion of the third path is located to the left or right of the battery.

[0039] According to this configuration, at least a portion of the third path can be easily supported (directly or indirectly) by the side wall of the battery, which makes it easier to stably support the third path.

[0040] Furthermore, in the present invention, it is preferable that the circulation direction of the cooling liquid is changeable.

[0041] With this configuration, an electric tractor can be realized that can switch between a state in which the first motor is cooled preferentially and a state in which the second motor is cooled preferentially, out of the first and second motors.

[0042] [3] The solution to problem [3] is as follows: The present invention is characterized in that it includes a battery, a first motor driven by power supplied from the battery, a traveling device driven by the first motor, a first cooling path through which a first coolant circulates, and a second cooling path through which a second coolant circulates, wherein the first cooling path includes the first motor and the second cooling path includes the battery.

[0043] With this configuration, the first motor and the battery are included in different cooling paths, so the coolant does not pass through one of the first motor and the battery and then the other, making it possible to realize an electric tractor in which the first motor and the battery are cooled effectively.

[0044] Furthermore, in the present invention, it is preferable that the first coolant and the second coolant are different types of coolants.

[0045] According to this configuration, a coolant suitable for cooling the first motor can be used as the first coolant, and a coolant suitable for cooling the battery can be used as the second coolant, thereby realizing an electric tractor in which the first motor and the battery are cooled more effectively.

[0046] Furthermore, in the present invention, it is preferable that the second coolant is an oil having insulating properties.

[0047] This configuration can prevent electrical interaction between the battery and the second coolant.

[0048] Furthermore, in the present invention, it is preferable to provide a first radiator that is included in the first cooling path and cools the first coolant, and a second radiator that is included in the second cooling path and cools the second coolant.

[0049] According to this configuration, the first coolant and the second coolant can be reliably cooled, and as a result, an electric tractor can be realized in which the first motor and the battery are more effectively cooled.

[0050] Furthermore, in the present invention, it is preferable that the working device further includes a second motor driven by power supplied from the battery, a transmission unit that transmits the driving force of the second motor to the working device, and a hydraulic pump driven by the second motor, and that the second motor is included in the first cooling path.

[0051] According to this configuration, the first motor is the power source for the travel device, and the second motor is the power source for the work device. This makes it easier to reliably obtain the power (horsepower) required to drive the travel device and the work device in an optimal manner, compared to when a single motor is used as a power source to drive the travel device and the work device.

[0052] Moreover, with this configuration, the first motor and the second motor are cooled by the first coolant, which prevents the first motor and the second motor from becoming too hot, which would otherwise cause a decrease in driving performance and working performance.

[0053] That is, with this configuration, it is possible to realize an electric tractor that can drive the traveling device and the working device in an optimal manner and maintain good traveling performance and working performance.

[0054] FIG. 1 is a left side view of an electric tractor. FIG. 2 is a plan view showing the configuration of a front frame and a storage frame, etc. FIG. 3 is a left side view showing the configuration of a first battery, etc. FIG. 4 is a right side view showing the configuration of the first battery, etc. FIG. 5 is a longitudinal front view showing the configuration of the first battery, etc. FIG. 6 is a left side view showing the configuration of a support mechanism. FIG. 7 is a right side view showing the configuration of the support mechanism. FIG. 8 is a plan view showing the configuration of the support mechanism. FIG. 9 is a left side view showing the configuration of a connecting portion, etc. FIG. 10 is a plan view showing the configuration of a first battery support portion and a second battery support portion, etc. FIG. 11 is a rear view showing the configuration of a first battery support portion and a second battery support portion, etc. FIG. 12 is a diagram showing the circulation paths of a first coolant and a second coolant. FIG. 13 is a diagram showing the configuration of a first cooling path and a second cooling path, etc. FIG. 14 is a diagram showing the circulation paths of a first coolant and a second coolant in a first alternative embodiment.

[0055] An embodiment of the present invention will be described with reference to the drawings. In the following description, unless otherwise specified, the direction of arrow F in the drawings will be referred to as "front," the direction of arrow B as "rear," the direction of arrow L as "left," and the direction of arrow R as "right." Furthermore, the direction of arrow U in the drawings will be referred to as "up," and the direction of arrow D as "down."

[0056] [Overall Configuration of Electric Tractor] As shown in Figure 1, in an electric tractor A, left and right front wheels 1 (corresponding to the "traveling device" according to the present invention) are provided at the front of the machine body. Also, left and right rear wheels 2 (corresponding to the "traveling device" according to the present invention) are provided at the rear of the machine body. The machine body is supported by the front wheels 1 and the rear wheels 2.

[0057] The electric tractor A includes left and right front frames 4, a storage frame 5, and a transmission case 6. As shown in Figures 1 and 2, the front frame 4 extends in the front-to-rear direction. The rear end of the front frame 4 is connected to the front portion of the storage frame 5. The transmission case 6 is connected to the rear portion of the storage frame 5.

[0058] 2, a first motor 11 and a second motor 12 are housed in the housing frame 5. The first motor 11 and the second motor 12 are both electric motors.

[0059] 1 and 2, a front axle case 7 is attached to the front frame 4. Left and right front wheels 1 are attached to the front axle case 7. Left and right rear wheels 2 are attached to the transmission case 6.

[0060] A driver's section 8 on which an operator can ride is provided above the accommodation frame 5 and the transmission case 6. That is, the electric tractor A is equipped with a driver's section 8 on which an operator can ride.

[0061] A ROPs frame 9 is attached to the transmission case 6 and extends upward. The ROPs frame 9 is provided behind the driver's section 8. A plurality of first batteries 10 (corresponding to the "batteries" according to the present invention) are supported by the front frame 4.

[0062] The plurality of first batteries 10 are arranged in the front portion of the electric tractor A. A hood 15 is provided to cover the plurality of first batteries 10. Although not particularly limited, the number of first batteries 10 in this embodiment is two.

[0063] One or more air inlet holes (not shown) are formed in the front part of the bonnet 15. Furthermore, the wind (air) generated by the vehicle traveling is introduced into the inside of the bonnet 15 via the air inlet holes.

[0064] The first motor 11 and the second motor 12 are driven by power supplied from a plurality of first batteries 10. Although not particularly limited, the plurality of first batteries 10 in this embodiment are electrically connected in series.

[0065] As described above, the electric tractor A is equipped with a first battery 10 disposed at the front of the vehicle body. More specifically, the electric tractor A is equipped with a plurality of first batteries 10. Even more specifically, the electric tractor A is equipped with two first batteries 10. The electric tractor A also is equipped with a first motor 11 and a second motor 12 that are driven by power supplied from the first batteries 10.

[0066] A first inverter 13 is attached to the left side of the storage frame 5. A second inverter 14 is attached to the right side of the storage frame 5. Electric power from the plurality of first batteries 10 is supplied to the first inverter 13. Based on operation of a speed change pedal 35 (see FIG. 1 ) of the driving unit 8, the first inverter 13 converts DC power from the plurality of first batteries 10 into AC power and supplies it to the first motor 11. This drives the first motor 11.

[0067] As described above, the electric tractor A is equipped with the first inverter 13 that converts DC power from the first battery 10 into AC power and supplies it to the first motor 11 .

[0068] The power of the plurality of first batteries 10 is supplied to the second inverter 14. The second inverter 14 converts the DC power from the plurality of first batteries 10 into AC power and supplies it to the second motor 12. This drives the second motor 12.

[0069] As described above, the electric tractor A is provided with the second inverter 14 that converts DC power from the first battery 10 into AC power and supplies it to the second motor 12 .

[0070] Although not particularly limited, the first inverter 13 and the second inverter 14 may each be housed in a case (not shown).

[0071] The first battery 10 is, for example, a lithium-ion battery. Although not shown, the first battery 10 includes small, low-voltage unit cells and a storage case. The first battery 10 includes a stack of multiple unit cells. The multiple unit cells are housed and sealed in the storage case. The output voltage of the first battery 10 is, for example, 400 volts.

[0072] A hydraulic multi-plate traveling clutch (not shown), a transmission (not shown), and a rear wheel differential (not shown), which are transmission mechanisms, are provided inside the transmission case 6. The transmission is configured as a gear-shift type and is capable of switching between two speed states: a high-speed state and a low-speed state. Power from the output shaft (not shown) of the first motor 11 is transmitted to the traveling clutch, from the traveling clutch to the transmission, and from the transmission to the rear wheels 2 via the rear wheel differential. The output shaft of the first motor 11 extends rearward.

[0073] Inside the transmission case 6, the power branched off between the transmission and the rear wheel differential device is transmitted to the front wheel transmission shaft 31 described later, from the front wheel transmission shaft 31 to the front wheel differential device (not shown) inside the front axle case 7, and from the front wheel differential device to the front wheels 1.

[0074] With the configuration described above, the left and right front wheels 1 and the left and right rear wheels 2 are driven by the first motor 11. That is, the electric tractor A has the left and right front wheels 1 and the left and right rear wheels 2 driven by the first motor 11.

[0075] A PTO shaft 28 (corresponding to the "transmission portion" according to the present invention) is provided facing rearward at the rear of the transmission case 6. A mid-PTO shaft 29 (corresponding to the "transmission portion" according to the present invention) is provided facing forward at the bottom of the transmission case 6. A hydraulic multi-plate PTO clutch (not shown) and a PTO transmission system (not shown), which serve as a transmission mechanism, are provided inside the transmission case 6.

[0076] The power of the output shaft (not shown) of the second motor 12 is transmitted to the PTO clutch, from the PTO clutch to the PTO transmission system, and from the PTO transmission system to the PTO shaft 28 and the mid-PTO shaft 29. The output shaft of the second motor 12 extends rearward.

[0077] As shown in Fig. 1 , when the implement E is attached to the rear of the machine body, the power of the PTO shaft 28 is transmitted to the implement E. As a result, the PTO shaft 28 transmits the driving force of the second motor 12 to the implement E. In the example shown in Fig. 1 , the implement E is a rotary tiller. However, the present invention is not limited to this. The implement E attached to the rear of the machine body may be any device other than a rotary tiller.

[0078] Furthermore, for example, when a working device E such as a mower (not shown) is attached between the front wheel 1 and the rear wheel 2 on the lower part of the machine body (in other words, in the center of the machine body in the longitudinal direction), the power of the mid-PTO shaft 29 is transmitted to the working device E. However, the present invention is not limited to this. The working device E attached to the center of the machine body in the longitudinal direction may be any device other than a mower.

[0079] With the configuration described above, the PTO shaft 28 and the mid-PTO shaft 29 transmit the driving force of the second motor 12 to the work device E. In other words, the electric tractor A is equipped with the PTO shaft 28 and the mid-PTO shaft 29 that transmit the driving force of the second motor 12 to the work device E.

[0080] The electric tractor A can travel while driving the work implement E by simultaneously driving the first motor 11 and the second motor 12 .

[0081] As shown in Figure 2, a pipe member 30 is provided between the rear of the housing frame 5 and the front axle case 7. The pipe member 30 extends in the front-to-rear direction. The front wheel transmission shaft 31 described above is provided inside the pipe member 30. The front wheel transmission shaft 31 is provided between the inside of the transmission case 6 and the front wheel differential device of the front axle case 7.

[0082] As shown in Figure 1, the driver's section 8 is provided with a steering wheel 33 for steering the front wheels 1, a driver's seat 34, a speed change pedal 35, a brake pedal 36, etc. An operator can sit in the driver's seat 34. When the operator operates the brake pedal 36, brakes (not shown) that can brake the left and right rear wheels 2 are activated. As a result, the left and right rear wheels 2 are subjected to a braking action.

[0083] A foot step 41 is attached to the lower left part of the driver's section 8. An operator uses this step 41 to get on and off the driver's section 8 mainly from the left side of the machine body.

[0084] [Configuration under the hood] As shown in Figures 3 to 5, the electric tractor A is equipped with an upper battery 21, a lower battery 22, a first radiator 38 (corresponding to the "radiator" according to the present invention), a second radiator 39, a third radiator 40, a cooling fan 42, a first reserve tank 43, and a second reserve tank 44.

[0085] The electric tractor A also includes a plurality of electrical components N. In this embodiment, the plurality of electrical components N specifically include a charge control device 23, a junction box 24, a first control unit 25, a second control unit 26, a second battery 27, and a voltage converter 37.

[0086] The upper battery 21, the lower battery 22, the charge control device 23, the junction box 24, the first control unit 25, the second control unit 26, the second battery 27, the voltage converter 37, the first radiator 38, the second radiator 39, the third radiator 40, the cooling fan 42, the first reserve tank 43, and the second reserve tank 44 are all covered (in other words, housed) by the hood 15.

[0087] The upper battery 21 and the lower battery 22 are both the first battery 10. That is, the electric tractor A is equipped with a hood 15 that covers the first battery 10. Although not particularly limited, the specifications of the upper battery 21 and the lower battery 22 are the same. In other words, the upper battery 21 and the lower battery 22 are the same type of battery.

[0088] The upper battery 21 is disposed above the lower battery 22. As a result, the plurality of first batteries 10 are aligned vertically. More specifically, two first batteries 10 are aligned vertically.

[0089] The lower surface of the upper battery 21 and the upper surface of the lower battery 22 are spaced apart from each other. That is, a gap G exists between the upper battery 21 and the lower battery 22. In this way, a gap G exists between the plurality of first batteries 10.

[0090] The electric tractor A also includes a charging socket (not shown). When an operator or the like inserts a charger adapter into the charging socket, each of the first batteries 10 is charged. The charging socket receives power for charging each of the first batteries 10. The standard of the charging socket may be, for example, CHAdeMO, CCS2, GB / T, ChaoJi, NACS, or the like.

[0091] The charge control device 23 may be a power module or a PLC (programmable logic controller) having a microcomputer that executes a program for charging each first battery 10, or may be a relay circuit that operates based on an electrical signal. The charge control device 23 controls the charging voltage and charging current for each first battery 10 when charging (including rapid charging) each first battery 10.

[0092] The junction box 24 is electrically connected to the first battery 10, the first inverter 13, the second inverter 14, the voltage converter 37, and the charging socket. The junction box 24 functions as a hub that distributes power from the first battery 10 to each of the first inverter 13, the second inverter 14, and the voltage converter 37. The junction box 24 also receives charging power from the charging socket and transmits it to the first battery 10.

[0093] The first control unit 25 and the second control unit 26 are both ECUs (electronic control units) that control various parts of the electric tractor A. Although not particularly limited, for example, the first control unit 25 may be an ECU for controlling electric components (more specifically, for example, the cooling fan 42 and the first and second pumps 86 and 87 described below), and the second control unit 26 may be an ECU for controlling the main unit (more specifically, for example, the first and second inverters 13 and 14).

[0094] The second battery 27 is a battery for the auxiliary equipment. The second battery 27 is, for example, a lead battery. The second battery 27 supplies low-voltage (e.g., 12 volts) power to drive the auxiliary equipment (e.g., the cooling fan 42 and the first and second pumps 86 and 87 described below). The output voltage of the second battery 27 is lower than the output voltage of the first battery 10. The second battery 27 may also supply power to ECUs such as the first control unit 25 and the second control unit 26.

[0095] Furthermore, power is sent from the first battery 10 to the voltage converter 37. The voltage converter 37 steps down the power from the first battery 10 and supplies it to the second battery 27. This allows the second battery 27 to be charged.

[0096] Thus, the multiple electrical components N include a second battery 27 for auxiliary equipment, a voltage converter 37 that reduces the voltage of the power from the first battery 10 and supplies it to the second battery 27, and a junction box 24.

[0097] The electric tractor A has a first cooling path J1 (corresponding to the "cooling path" according to the present invention) and a second cooling path J2 through which a coolant circulates. The first coolant (corresponding to the "cooling path" according to the present invention) circulates through the first cooling path J1. The second coolant circulates through the second cooling path J2. That is, the electric tractor A has the first cooling path J1 through which the first coolant circulates and the second cooling path J2 through which the second coolant circulates.

[0098] Although not particularly limited, in this embodiment, the first coolant and the second coolant are different types of coolants. Specifically, the first coolant is a known LLC (long life coolant), and the second coolant is an oil having insulating properties.

[0099] The first radiator 38 is included in the first cooling path J1. The first radiator 38 cools the first coolant. That is, the electric tractor A has the first radiator 38 that is included in the first cooling path J1 and cools the first coolant.

[0100] The second radiator 39 is included in the second cooling path J2. The second radiator 39 cools the second coolant. That is, the electric tractor A has the second radiator 39, which is included in the second cooling path J2 and cools the second coolant.

[0101] The third radiator 40 is included in the second cooling path J2. The third radiator 40 cools the second coolant.

[0102] The third radiator 40 is disposed below the first radiator 38. The first radiator 38 and the third radiator 40 constitute a radiator device K. The second radiator 39 is disposed in front of the radiator device K.

[0103] The cooling fan 42 is disposed behind the first radiator 38, the second radiator 39, and the third radiator 40. The cooling fan 42 blows cooling air rearward. As a result, outside air is introduced into the inside of the hood 15 through the air inlet holes and passes through the first radiator 38, the second radiator 39, and the third radiator 40. As a result, the first radiator 38, the second radiator 39, and the third radiator 40 are cooled.

[0104] The cooling fan 42 is disposed in front of the upper battery 21 and the lower battery 22. The cooling fan 42 is disposed in front of the lower battery 22.

[0105] The first reserve tank 43 is included in the first cooling path J1. The first reserve tank 43 is capable of storing the first coolant.

[0106] The second reserve tank 44 is included in the second cooling path J2. The second reserve tank 44 is capable of storing the second coolant.

[0107] 3 to 5 , the charge control device 23 and the junction box 24 are disposed on the left side of the first battery 10. The first control unit 25, the second control unit 26, the second battery 27, and the voltage converter 37 are disposed on the right side of the first battery 10. That is, the multiple electrical components N are disposed on the left and right sides of the first battery 10. Furthermore, the voltage converter 37 and the junction box 24 are disposed on the left and right sides of the first battery 10.

[0108] 3 to 5 show a reference position T. The reference position T is the lower end position of the upper battery 21. The charge control device 23, the second reserve tank 44, the first control unit 25, the second control unit 26, and the second battery 27 are all located above the reference position T. The voltage converter 37 and the junction box 24 are all located below the reference position T.

[0109] In this way, the electrical components N are arranged above and below the lower end position of the upper first battery 10. Furthermore, the voltage converter 37 and the junction box 24 are both arranged below the lower end position of the upper first battery 10.

[0110] As shown in Fig. 3, the second reserve tank 44 is located in front of the charge control device 23. As shown in Fig. 4, the second control unit 26 is located in front of the first control unit 25. In addition, the second battery 27 is located in front of the second control unit 26.

[0111] 3 and 5, a first support stay 46 and a second support stay 47 are provided on the left wall of the upper battery 21. The first support stay 46 and the second support stay 47 may be part of the upper battery 21, or may not be included in the upper battery 21.

[0112] The second support stay 47 is disposed rearward of the first support stay 46. A front support portion 44a extending forward is provided at the front end of the second reserve tank 44. A rear support portion 44b extending rearward is provided at the rear end of the second reserve tank 44.

[0113] The front support portion 44a is supported by the first support stay 46 while abutting against the first support stay 46 from above. The rear support portion 44b is supported by the second support stay 47 while abutting against the second support stay 47 from above. As a result, the second reserve tank 44 is supported on the left side wall of the upper battery 21 via the first support stay 46 and the second support stay 47.

[0114] A first plate-shaped member 48 is attached to the second support stay 47 by, for example, welding or bolting. The first plate-shaped member 48 is disposed behind the second support stay 47. The first plate-shaped member 48 is disposed in a position facing the left wall of the upper battery 21.

[0115] The charging control device 23 is supported by the first plate-shaped member 48 while abutting against the first plate-shaped member 48 from the left side. The charging control device 23 may be fixed to the first plate-shaped member 48 by, for example, bolting.

[0116] 4 and 5, a third support stay 49 and a fourth support stay 50 are provided on the right wall of the upper battery 21. The third support stay 49 and the fourth support stay 50 may be part of the upper battery 21, or may not be included in the upper battery 21.

[0117] As shown in Figures 4 and 5, the electric tractor A is equipped with a second plate-shaped member 51. The second plate-shaped member 51 has an upper portion 51a, a horizontal portion 51b, and a lower portion 51c. The upper portion 51a and the lower portion 51c are both in a vertical position and face the right wall of the upper battery 21. The horizontal portion 51b is in a horizontal position.

[0118] The lower end of the upper portion 51a is connected to the left end of the horizontal portion 51b, and the upper end of the lower portion 51c is connected to the right end of the horizontal portion 51b.

[0119] The horizontal portion 51b is supported by the third support stay 49 while abutting against the third support stay 49 from above. In this way, the second plate-shaped member 51 is supported by the third support stay 49. The second plate-shaped member 51 may be fixed to the third support stay 49 by, for example, bolting.

[0120] The first control unit 25 and the second control unit 26 are supported by the upper portion 51 a in a state of contacting the upper portion 51 a from the right side. The first control unit 25 and the second control unit 26 may be fixed to the upper portion 51 a by, for example, bolting.

[0121] As a result, the first control unit 25 and the second control unit 26 are supported on the right side wall of the upper battery 21 via the second plate-shaped member 51 and the third support stay 49 .

[0122] 4 and 5 , the second battery 27 is supported by the fourth support stay 50 while abutting against the fourth support stay 50 from above. As a result, the second battery 27 is supported on the right side wall of the upper battery 21 via the fourth support stay 50.

[0123] 3 to 5, the electric tractor A includes a support mechanism W. The support mechanism W is supported by the left and right front frames 4. The voltage converter 37 and the junction box 24 are both supported by the support mechanism W.

[0124] As shown in FIGS. 3 and 4, the cooling fan 42 and the radiator unit K are supported by the left and right front frames 4.

[0125] An upper support member 52 is provided spanning the upper end of the radiator device K and the upper end of the second radiator 39. Furthermore, a lower support member 53 is provided spanning the lower end of the radiator device K and the lower end of the second radiator 39. The second radiator 39 is supported by the upper support member 52 and the lower support member 53. As a result, the second radiator 39 is supported by the radiator device K via the upper support member 52 and the lower support member 53.

[0126] The first reserve tank 43 is supported by the radiator device K in a state where it abuts against the radiator device K from above.

[0127] [Configuration of Support Mechanism] As shown in FIG. 2 , the electric tractor A includes a third plate-shaped member 54 , a fifth support stay 55 , and a sixth support stay 56 .

[0128] The third plate-like member 54 is a horizontally oriented plate-like member. The third plate-like member 54 is disposed across the left and right front frames 4. As shown in Fig. 5 , the third plate-like member 54 is supported by the left and right front frames 4 while abutting against the left and right front frames 4 from above.

[0129] 5, the electric tractor A is also provided with a channel-shaped reinforcing frame 73. The reinforcing frame 73 is sandwiched between the left and right front frames 4 and fixed to the left and right front frames 4 by, for example, welding. The reinforcing frame 73 also abuts against the third plate-shaped member 54 from below. The reinforcing frame 73 is fixed to the third plate-shaped member 54 by, for example, welding.

[0130] The fifth support stay 55 and the sixth support stay 56 shown in Fig. 2 are both plate-like members bent into an L shape. The fifth support stay 55 is attached to the left front frame 4. The sixth support stay 56 is attached to the right front frame 4. The fifth support stay 55 and the sixth support stay 56 are disposed rearward of the third plate-like member 54.

[0131] 6 to 8 , the support mechanism W is made up of left and right support frames 58, a bottom plate portion 59, and a fourth plate-like member 62. That is, the support mechanism W has left and right support frames 58.

[0132] The left and right support frames 58 are made up of a left support frame 60 and a right support frame 61. The left support frame 60 is the left side support frame 58. The right support frame 61 is the right side support frame 58.

[0133] The left support frame 60 is disposed along the left side wall of the lower battery 22. The right support frame 61 is disposed along the right side wall of the lower battery 22. That is, each support frame 58 is disposed along the side wall of the lower battery 22. The lower battery 22 is disposed between the left and right support frames 58.

[0134] The bottom plate portion 59 is a horizontally oriented plate-like member. The left and right support frames 58 are supported by the bottom plate portion 59 while abutting against the bottom plate portion 59 from above. The left and right support frames 58 are attached to the bottom plate portion 59 by, for example, welding or bolting.

[0135] 5 and 8 , a hole 59a is provided in the front portion of the bottom plate portion 59. The fourth plate-shaped member 62 is a horizontally oriented plate-shaped member. The fourth plate-shaped member 62 is attached to the bottom surface of the bottom plate portion 59 by, for example, welding or bolting, so as to cover the hole 59a from below.

[0136] 6 and 7 , the fourth plate-shaped member 62 is supported by the third plate-shaped member 54 while abutting against the third plate-shaped member 54 from above. As a result, the front portion of the support mechanism W is supported by the left and right front frames 4 via the third plate-shaped member 54.

[0137] 5, the fourth plate-shaped member 62, the third plate-shaped member 54, and the reinforcing frame 73 are fastened together by fixing bolts 74. Furthermore, bolt holes 62a are formed in the fourth plate-shaped member 62. The fixing bolts 74 are inserted into the bolt holes 62a. Note that the number of fixing bolts 74 and the number of bolt holes 62a may be any number.

[0138] As shown in FIG. 8, in a plan view, the bolt hole 62a is provided inside the hole 59a (in other words, at a position corresponding to the hole 59a).

[0139] 6 and 7 , the rear portion of the support mechanism W is supported by the fifth support stay 55 and the sixth support stay 56 while abutting against the fifth support stay 55 and the sixth support stay 56 from above. As a result, the rear portion of the support mechanism W is supported by the left and right front frames 4 via the fifth support stay 55 and the sixth support stay 56.

[0140] 6 and 8 , the left support frame 60 includes a first column frame 63, a second column frame 64, a first connecting frame 65, and a second connecting frame 66. The first column frame 63 and the second column frame 64 both extend in the vertical direction. The lower ends of the first column frame 63 and the second column frame 64 are attached to the upper surface of the bottom plate portion 59 by, for example, welding or bolting. The first column frame 63 is located forward of the second column frame 64.

[0141] The first connecting frame 65 and the second connecting frame 66 both extend in the front-to-rear direction. The first connecting frame 65 is positioned higher than the second connecting frame 66. The front end of the first connecting frame 65 is connected to the upper part of the first pillar frame 63. The rear end of the first connecting frame 65 is connected to the upper part of the second pillar frame 64. The front end of the second connecting frame 66 is connected to the lower part of the first pillar frame 63. The rear end of the second connecting frame 66 is connected to the lower part of the second pillar frame 64. The first connecting frame 65 and the second connecting frame 66 are spaced apart from each other in the up-down direction.

[0142] 7 and 8 , the right support frame 61 includes a third pillar frame 67, a fourth pillar frame 68, a third connecting frame 69, and a fourth connecting frame 70. The third pillar frame 67 and the fourth pillar frame 68 both extend in the vertical direction. The lower ends of the third pillar frame 67 and the fourth pillar frame 68 are attached to the upper surface of the bottom plate portion 59 by, for example, welding or bolting. The third pillar frame 67 is located forward of the fourth pillar frame 68.

[0143] The third connection frame 69 and the fourth connection frame 70 both extend in the front-to-rear direction. The third connection frame 69 is positioned higher than the fourth connection frame 70. The front end of the third connection frame 69 is connected to the upper part of the third pillar frame 67. The rear end of the third connection frame 69 is connected to the upper part of the fourth pillar frame 68. The front end of the fourth connection frame 70 is connected to the lower part of the third pillar frame 67. The rear end of the fourth connection frame 70 is connected to the lower part of the fourth pillar frame 68. The third connection frame 69 and the fourth connection frame 70 are spaced apart from each other in the up-down direction.

[0144] 6 to 8 , the first support section S1 is configured by the bottom plate section 59, the first pillar frame 63, the second pillar frame 64, the third pillar frame 67, and the fourth pillar frame 68. The first support section S1 supports the upper battery 21 and the lower battery 22. That is, the first support section S1 supports the multiple first batteries 10.

[0145] 5 to 7 , the left front portion of the upper battery 21 is supported by the upper end of the first pillar frame 63 at the first support portion S1 via the first elastic member 71. The right front portion of the upper battery 21 is supported by the upper end of the third pillar frame 67 at the first support portion S1 via the first elastic member 71. The left rear portion of the upper battery 21 is supported by the upper end of the second pillar frame 64 at the first support portion S1 via the first elastic member 71. The right rear portion of the upper battery 21 is supported by the upper end of the fourth pillar frame 68 at the first support portion S1 via the first elastic member 71.

[0146] The left front portion of the lower battery 22 is supported by the left front portion of the bottom plate portion 59 of the first support portion S1 via the first elastic member 71. The right front portion of the lower battery 22 is supported by the right front portion of the bottom plate portion 59 of the first support portion S1 via the first elastic member 71. The left rear portion of the lower battery 22 is supported by the left rear portion of the bottom plate portion 59 of the first support portion S1 via the first elastic member 71. The right rear portion of the lower battery 22 is supported by the right rear portion of the bottom plate portion 59 of the first support portion S1 via the first elastic member 71.

[0147] The first elastic member 71 is not particularly limited, but may be, for example, a rubber mount.

[0148] 6 to 8, the second support portion S2 is formed by the first connecting frame 65, the second connecting frame 66, the third connecting frame 69, and the fourth connecting frame 70. The second support portion S2 supports the electrical equipment N (more specifically, the junction box 24 and the voltage converter 37). That is, the electric tractor A is provided with a support mechanism W having the first support portion S1 and the second support portion S2.

[0149] More specifically, the junction box 24 is supported by the first connecting frame 65 and the second connecting frame 66 in a state in which the junction box 24 abuts against the first connecting frame 65 and the second connecting frame 66 at the second support portion S2 from the left side. The junction box 24 is attached to the first connecting frame 65 and the second connecting frame 66 by, for example, bolting.

[0150] The voltage converter 37 is supported by the third connecting frame 69 and the fourth connecting frame 70 in a state in which the voltage converter 37 abuts against the third connecting frame 69 and the fourth connecting frame 70 at the second support portion S2 from the right side. The voltage converter 37 is attached to the third connecting frame 69 and the fourth connecting frame 70 by, for example, bolting.

[0151] [Hydraulic Pump] As shown in Figure 2, the electric tractor A is equipped with a hydraulic pump 72. The hydraulic pump 72 is attached to the right rear portion of the storage frame 5. The power of the output shaft (not shown) of the second motor 12 is transmitted to a power transmission gear (not shown), and then transmitted from the power transmission gear to an input shaft (not shown) of the hydraulic pump 72. In this way, the power of the second motor 12 is transmitted to the hydraulic pump 72. As a result, the hydraulic pump 72 is driven.

[0152] In this way, the electric tractor A is equipped with a hydraulic pump 72 driven by the second motor 12 .

[0153] The power transmission gear is housed in the rear part of the housing frame 5. The input shaft of the hydraulic pump 72 extends forward.

[0154] The hydraulic pump 72 supplies hydraulic oil to each part of the electric tractor A. For example, if a front loader device (not shown) is attached to the machine body, the front loader device operates when hydraulic oil is supplied from the hydraulic pump 72 to the front loader device. In addition, various hydraulic devices (not shown) in the machine body operate when hydraulic oil is supplied from the hydraulic pump 72 to the hydraulic devices.

[0155] 1 to 3, a handle support mechanism 16 is provided at the front end of the driver's section 8. A steering handle 33 is supported by the handle support mechanism 16.

[0156] 9 and 10, a pillar frame 18 is provided in front of the handle support mechanism 16. As shown in Fig. 11, the pillar frame 18 is configured in an arch shape (gate shape) when viewed from behind. The pillar frame 18 is supported by the storage frame 5 while abutting against the storage frame 5 from above.

[0157] 9 and 11 , the electric tractor A includes a shaft support portion 75 and a shaft member 76. The shaft support portion 75 is fixed to the upper end portion of the pillar frame 18. The shaft support portion 75 extends upward from the upper end portion of the pillar frame 18.

[0158] The shaft member 76 extends in the left-right direction of the vehicle body. The shaft member 76 is supported by the shaft support portion 75. As a result, the shaft member 76 is supported by the pillar frame 18 via the shaft support portion 75. In other words, the shaft member 76 is supported by the pillar frame 18. Note that the number of shaft support portions 75 and the number of shaft members 76 may be any number.

[0159] 1, 9, and 11, the hood 15 is supported by the shaft member 76 in a state in which it can swing up and down around the shaft member 76. As a result, the hood 15 is supported by the pillar frame 18 via the shaft member 76 and the shaft support portion 75. This also allows the hood 15 to be opened and closed.

[0160] That is, the electric tractor A includes pillar frames 18 that support the hood 15. The hood 15 can be opened and closed by swinging up and down about a shaft member 76 that extends in the left-right direction of the vehicle body.

[0161] 10 and 11 , the electric tractor A includes a first battery support portion 77 and a second battery support portion 78. The first battery support portion 77 is disposed across the upper left portion of the pillar frame 18 and the upper left portion of the upper battery 21. The left end portion of the first battery support portion 77 is fixed to the upper left portion of the pillar frame 18 by welding, for example. The right end portion of the first battery support portion 77 is fixed to the upper left portion of the upper battery 21 by bolting, for example.

[0162] The second battery support portion 78 is disposed so as to span the upper right portion of the pillar frame 18 and the upper right portion of the upper battery 21. The right end portion of the second battery support portion 78 is fixed to the upper right portion of the pillar frame 18 by, for example, welding, etc. The left end portion of the second battery support portion 78 is fixed to the upper right portion of the upper battery 21 by, for example, bolting, etc.

[0163] With this configuration, the upper battery 21 is supported by the pillar frame 18 via the first battery support portion 77 and the second battery support portion 78. In other words, the upper battery 21 is supported by the pillar frame 18.

[0164] 9 and 11, the electric tractor A includes a seventh support stay 79 and a second elastic member 80. The seventh support stay 79 is fixed to the upper end of the pillar frame 18. The seventh support stay 79 extends rearward from the upper end of the pillar frame 18. The second elastic member 80 is attached to the rear end of the seventh support stay 79. Although not particularly limited, the second elastic member 80 may be made of rubber, for example.

[0165] 9 , the second elastic member 80 contacts the front end (more specifically, the front wall) of the handle support mechanism 16. When the hood 15 is opened or closed, the second elastic member 80 suppresses vibrations of the hood 15 and the pillar frames 18 that accompany the opening and closing of the hood 15.

[0166] 9 to 11 , the electric tractor A has left and right connecting portions 81. Each connecting portion 81 is provided across the pillar frame 18 and the front end portion of the handle support mechanism 16. In other words, the electric tractor A has the connecting portion 81 across the pillar frame 18 and the driving portion 8.

[0167] Each connecting portion 81 has a first connecting portion 82, a second connecting portion 83, a third elastic member 84, and a fourth elastic member 85. Although not particularly limited, the third elastic member 84 and the fourth elastic member 85 may be made of rubber, for example.

[0168] The first connecting portion 82 is attached to the pillar frame 18 via a third elastic member 84. The first connecting portion 82 extends rearward from the pillar frame 18.

[0169] The second connecting portion 83 is attached to the rear end of the first connecting portion 82 via a fourth elastic member 85. The second connecting portion 83 is then connected to the front end (more specifically, the front wall) of the handle support mechanism 16 by, for example, welding or bolting.

[0170] With the configuration described above, the pillar frame 18 is connected to the driving section 8 via the left and right connecting sections 81. However, the present invention is not limited to this, and any number of connecting sections 81 may be provided.

[0171] When an operator gets on or off the driving unit 8, vibrations may occur in the driving unit 8. The fourth elastic member 85 prevents vibrations transmitted from the driving unit 8 to the second connecting portion 83 from being transmitted from the second connecting portion 83 to the first connecting portion 82. As a result, the vibrations of the driving unit 8 are prevented from being transmitted to the pillar frame 18.

[0172] Furthermore, the third elastic member 84 suppresses the transmission of vibrations transmitted from the driving section 8 to the first connecting section 82 via the second connecting section 83 from the first connecting section 82 to the pillar frame 18. As a result, the transmission of vibrations of the driving section 8 to the pillar frame 18 is suppressed.

[0173] In this way, the connecting portion 81 has the third elastic member 84 and the fourth elastic member 85 that suppress the transmission of vibrations of the driver's section 8 to the pillar frame 18 .

[0174] 3 and 4, the electric tractor A includes a first pump 86 and a second pump 87. The first pump 86 and the second pump 87 are both disposed below the lower battery 22.

[0175] 12 , the first pump 86 and the second pump 87 are included in the first cooling path J1. The first pump 86 and the second pump 87 may be configured to be driven by power supplied from the second battery 27, for example. The first pump 86 and the second pump 87 pump the first coolant.

[0176] The first cooling path J1 includes a first inverter 13, a first motor 11, a second motor 12, a second inverter 14, a voltage converter 37, a first reserve tank 43, and a first radiator 38.

[0177] That is, the first cooling path J1 includes the voltage converter 37. The first cooling path J1 also includes the first motor 11. The first cooling path J1 also includes the second motor 12.

[0178] The first cooling path J1 includes a first path P1, a second path P2, and a third path P3. The first path P1 connects the first radiator 38 and the first motor 11. In the first path P1, the first coolant flows from the first radiator 38 toward the first motor 11.

[0179] The second path P2 connects the first motor 11 and the second motor 12. The first coolant flows from the first motor 11 to the second motor 12 through the second path P2.

[0180] The third path P3 connects the second motor 12 and the first radiator 38. In the third path P3, the first coolant flows from the second motor 12 toward the first radiator 38.

[0181] That is, the first cooling path J1 has a first radiator 38 that cools the first coolant, a first path P1 along which the first coolant flows from the first radiator 38 toward the first motor 11, a second path P2 along which the first coolant flows from the first motor 11 toward the second motor 12, and a third path P3 along which the first coolant flows from the second motor 12 toward the first radiator 38.

[0182] The first path P1 will now be described in detail. The first path P1 includes a first hose 96, a first pump 86, a second hose 88, a second pump 87, a third hose 89, a first inverter 13, and a fourth hose 90. That is, the first inverter 13 is included in the first path P1.

[0183] The first hose 96 connects the first radiator 38 and the first pump 86. The second hose 88 connects the first pump 86 and the second pump 87. The third hose 89 connects the second pump 87 and the first inverter 13. The fourth hose 90 connects the first inverter 13 and the first motor 11.

[0184] 3 , 4 , and 13 , a portion of the first hose 96 and a portion of the third hose 89 are located below the upper battery 21 and the lower battery 22. Furthermore, the first pump 86, the second hose 88, and the second pump 87 are located below the upper battery 21 and the lower battery 22. In this manner, at least a portion of the first path P1 is located below the first battery 10. Note that only a portion of the first path P1 may be located below the first battery 10, or the entire first path P1 may be located below the first battery 10.

[0185] 12 , the second path P2 is formed by a fifth hose 91. The fifth hose 91 connects the first motor 11 and the second motor 12.

[0186] The third path P3 will now be described in detail. The third path P3 includes the sixth hose 92, the second inverter 14, the seventh hose 93, the voltage converter 37, the eighth hose 94, the first reserve tank 43, and the ninth hose 95. That is, the second inverter 14 is included in the third path P3.

[0187] 3, 4, and 13, a portion of the seventh hose 93 and a portion of the eighth hose 94 are located to the right of the lower battery 22. In addition, a portion of the eighth hose 94 is located to the right of the upper battery 21. In addition, the voltage converter 37 is located to the right of the lower battery 22.

[0188] As a result, at least a portion of the third path P3 is located to the right of the first battery 10. However, the present invention is not limited to this. For example, the arrangement of the seventh hose 93, the eighth hose 94, and the voltage converter 37 may be reversed in the left-right direction. That is, at least a portion of the third path P3 is located to the left or right of the first battery 10. Only a portion of the third path P3 may be located to the left or right of the first battery 10, or the entire third path P3 may be located to the left or right of the first battery 10.

[0189] 12 , the first pump 86 and the second pump 87 are connected in series by a second hose 88. The first coolant pumped by the first pump 86 and the second pump 87 flows through the third hose 89, the first inverter 13, the fourth hose 90, the first motor 11, the fifth hose 91, the second motor 12, the sixth hose 92, the second inverter 14, the seventh hose 93, the voltage converter 37, the eighth hose 94, the first reserve tank 43, the ninth hose 95, the first radiator 38, and the first hose 96 in this order, before returning to the first pump 86 and the second pump 87.

[0190] 3, 4, and 13, the ninth hose 95 is not shown. Instead of providing the ninth hose 95, the first reserve tank 43 and the first radiator 38 may be directly connected to each other.

[0191] 3 and 4, the electric tractor A includes a third pump 17 and a battery heater 19. The third pump 17 is disposed below the radiator device K and the second radiator 39. The battery heater 19 is disposed below the lower battery 22.

[0192] 12, the third pump 17 and the battery heater 19 are included in the second cooling path J2. The third pump 17 may be configured to be driven by power supplied from the second battery 27, for example. The third pump 17 pumps the second coolant.

[0193] The battery heater 19 may also be configured to be driven by power supplied from the second battery 27. The battery heater 19 heats the second coolant when the upper battery 21 and the lower battery 22 are in a low-temperature state.

[0194] The second cooling path J2 includes the upper battery 21, the lower battery 22, the third radiator 40, the second radiator 39, and the second reserve tank 44. That is, the second cooling path J2 includes the first battery 10.

[0195] The second cooling path J2 includes a tenth hose 97, an eleventh hose 98, a twelfth hose 99, a thirteenth hose 100, a fourteenth hose 101, a fifteenth hose 102, and a sixteenth hose 103.

[0196] The tenth hose 97 connects the third pump 17 and the battery heater 19. The eleventh hose 98 connects the battery heater 19 and the upper battery 21. The twelfth hose 99 connects the upper battery 21 and the lower battery 22. The thirteenth hose 100 connects the lower battery 22 and the third radiator 40. The fourteenth hose 101 connects the third radiator 40 and the second radiator 39. The fifteenth hose 102 connects the second radiator 39 and the second reserve tank 44. The sixteenth hose 103 connects the second reserve tank 44 and the third pump 17.

[0197] 3, 4, and 13, a portion of the fifteenth hose 102 and a portion of the sixteenth hose 103 are located to the left of the upper battery 21. In addition, a portion of the sixteenth hose 103 is located to the left of the lower battery 22. In addition, the second reserve tank 44 is located to the left of the upper battery 21.

[0198] As a result, at least a portion of the second cooling path J2 is located to the left of the first battery 10. However, the present invention is not limited to this. For example, the arrangement of the fifteenth hose 102, the sixteenth hose 103, and the second reserve tank 44 may be reversed in the left-right direction.

[0199] With the configuration described above, at least a portion of the first cooling path J1 (more specifically, the third path P3) passes through one of the left and right sides (the right side in this embodiment) of the first battery 10. Also, at least a portion of the second cooling path J2 passes through the other of the left and right sides (the left side in this embodiment) of the first battery 10.

[0200] Only a portion of the first cooling path J1 may pass through one of the left and right sides of the first battery 10, or the entire first cooling path J1 may pass through one of the left and right sides of the first battery 10. Also, only a portion of the second cooling path J2 may pass through the other of the left and right sides of the first battery 10, or the entire second cooling path J2 excluding the first battery 10 may pass through the other of the left and right sides of the first battery 10.

[0201] As shown in Figure 12, the second coolant pumped by the third pump 17 flows in the following order: the tenth hose 97, the battery heater 19, the eleventh hose 98, the upper battery 21, the twelfth hose 99, the lower battery 22, the thirteenth hose 100, the third radiator 40, the fourteenth hose 101, the second radiator 39, the fifteenth hose 102, the second reserve tank 44, and the sixteenth hose 103, before returning to the third pump 17.

[0202] 12, the first cooling path J1 and the second cooling path J2 do not communicate with each other, that is, the first cooling path J1 and the second cooling path J2 are independent from each other.

[0203] According to the configuration described above, the vehicle is provided with a first motor 11 that is the power source for the left and right front wheels 1 and the left and right rear wheels 2, and a second motor 12 that is the power source for the working device E. This makes it easier to reliably obtain the power (horsepower) required to suitably drive the left and right front wheels 1, the left and right rear wheels 2, and the working device E, compared to when a single motor is used as the power source to drive the left and right front wheels 1, the left and right rear wheels 2, and the working device E.

[0204] Moreover, with the configuration described above, the coolant that has passed through the first radiator 38 passes through the first motor 11 first out of the first motor 11 and the second motor 12. This allows the first motor 11 to be cooled preferentially. This prevents the first motor 11 from becoming too hot, which would result in a decrease in driving performance.

[0205] That is, according to the configuration described above, the left and right front wheels 1, the left and right rear wheels 2, and the working implement E can be driven appropriately, and an electric tractor A with good running performance can be realized.

[0206] According to the configuration described above, the first motor 11 and the first battery 10 are included in different cooling paths. Therefore, the coolant does not pass through one of the first motor 11 and the first battery 10 and then the other. This makes it possible to realize an electric tractor A in which the first motor 11 and the first battery 10 are effectively cooled.

[0207] [First Alternative Embodiment] In the first cooling path J1 of the above-described embodiment, the first coolant circulates in the direction shown in FIG.

[0208] However, the present invention is not limited to this. Below, a first alternative embodiment of the present invention will be described, focusing on the differences from the above embodiment. The configuration other than the parts described below is the same as the above embodiment. Furthermore, the same reference numerals are used to designate the same components as the above embodiment.

[0209] In the first cooling path J1 of the first alternative embodiment according to the present invention, the direction in which the first pump 86 and the second pump 87 pump the first cooling liquid is opposite to that in the above-described embodiment, so that the first cooling liquid circulates in the direction shown in FIG.

[0210] More specifically, in the first path P1, the first coolant flows from the first motor 11 toward the first radiator 38. In addition, in the second path P2, the first coolant flows from the second motor 12 toward the first motor 11. In addition, in the third path P3, the first coolant flows from the first radiator 38 toward the second motor 12.

[0211] That is, the first cooling path J1 has a first radiator 38 that cools the first coolant, a first path P1 along which the first coolant flows from the first motor 11 to the first radiator 38, a second path P2 along which the first coolant flows from the second motor 12 to the first motor 11, and a third path P3 along which the first coolant flows from the first radiator 38 to the second motor 12.

[0212] Furthermore, the circulation direction of the first coolant may be switchable between the direction shown in Fig. 12 and the direction shown in Fig. 14 in response to a predetermined manual operation by an operator or automatically. That is, the circulation direction of the first coolant may be changeable.

[0213] According to the configuration described above, the vehicle is provided with a first motor 11 that is the power source for the left and right front wheels 1 and the left and right rear wheels 2, and a second motor 12 that is the power source for the working device E. This makes it easier to reliably obtain the power (horsepower) required to suitably drive the left and right front wheels 1, the left and right rear wheels 2, and the working device E, compared to when a single motor is used as the power source to drive the left and right front wheels 1, the left and right rear wheels 2, and the working device E.

[0214] Moreover, with the configuration described above, the coolant that has passed through the first radiator 38 passes through the second motor 12 first, out of the first motor 11 and the second motor 12. This allows the second motor 12 to be cooled preferentially. This prevents the second motor 12 from becoming too hot, which would result in a decrease in work performance.

[0215] That is, according to the configuration described above, the left and right front wheels 1, the left and right rear wheels 2, and the working implement E can be driven appropriately, and an electric tractor A with good working performance can be realized.

[0216] Other Embodiments (1) The arrangement of some or all of the components may be reversed in the left-right direction.

[0217] (2) The electric tractor A may be equipped with an engine and configured as a hybrid.

[0218] (3) The number of first batteries 10 provided may be one.

[0219] (4) The first inverter 13 does not have to be included in the first path P1.

[0220] (5) The second inverter 14 does not have to be included in the third path P3.

[0221] (6) The first path P1 does not have to pass under the first battery 10.

[0222] (7) The third path P3 does not have to pass to the left of the first battery 10 and does not have to pass to the right of the first battery 10.

[0223] (8) The power from the first motor 11 may not be transmitted to the left and right front wheels 1 .

[0224] (9) The power from the first motor 11 may not be transmitted to the left and right rear wheels 2 .

[0225] (10) The second motor 12 does not have to be provided.

[0226] (11) The first coolant and the second coolant may be the same type of coolant.

[0227] (12) The second coolant does not have to be an oil having insulating properties.

[0228] (13) The first coolant and the second coolant may be cooled by a single radiator.

[0229] (14) The second motor 12 may be included in the second cooling path J2.

[0230] The configurations disclosed in the above-described embodiments (including other embodiments, the same applies hereinafter) can be applied in combination with the configurations disclosed in other embodiments, unless a contradiction occurs. Furthermore, the embodiments disclosed in this specification are merely examples, and the present invention is not limited to these, and can be modified as appropriate within the scope of the present invention.

[0231] The present invention can be used in electric tractors.

[0232] 1: Front wheels (traveling device) 2: Rear wheels (traveling device) 10: First battery (battery) 11: First motor 12: Second motor 13: First inverter 14: Second inverter 28: PTO shaft (transmission section) 29: Mid PTO shaft (transmission section) 38: First radiator (radiator) 39: Second radiator 72: Hydraulic pump A: Electric tractor E: Work device J1: First cooling path (cooling path) J2: Second cooling path P1: First path P2: Second path P3: Third path

Claims

1. A battery, a first motor and a second motor driven by electric power supplied from the battery, a traveling device driven by the first motor, a transmission unit that transmits the driving force of the second motor to a working device, a hydraulic pump driven by the second motor, and a cooling path through which a coolant circulates, the cooling path including a radiator that cools the coolant, a first path through which the coolant flows from the radiator toward the first motor, a second path through which the coolant flows from the first motor toward the second motor, and a third path through which the coolant flows from the second motor toward the radiator. An electric tractor having these components.

2. The electric tractor according to claim 1, further comprising a first inverter that converts DC power from the battery into AC power and supplies the AC power to the first motor, and the first inverter is included in the first path.

3. The electric tractor according to claim 1 or 2, further comprising a second inverter that converts DC power from the battery into AC power and supplies the AC power to the second motor, and the second inverter is included in the third path.

4. The electric tractor according to any one of claims 1 to 3, wherein at least a part of the first path is located below the battery.

5. The electric tractor according to any one of claims 1 to 4, wherein at least a part of the third path is located to the left or right of the battery.

6. The electric tractor according to any one of claims 1 to 5, wherein the circulation direction of the coolant can be changed.

7. A battery, a first motor and a second motor driven by electric power supplied from the battery, a traveling device driven by the first motor, a transmission unit that transmits the driving force of the second motor to a working device, a hydraulic pump driven by the second motor, and a cooling path through which a coolant circulates, the cooling path including a radiator that cools the coolant, a first path through which the coolant flows from the first motor toward the radiator, a second path through which the coolant flows from the second motor toward the first motor, and a third path through which the coolant flows from the radiator toward the second motor. An electric tractor having these components.

8. The electric tractor according to claim 7, comprising a first inverter that converts DC power from the battery into AC power and supplies it to the first motor, and the first inverter is included in the first path.

9. The electric tractor according to claim 7 or 8, comprising a second inverter that converts DC power from the battery into AC power and supplies it to the second motor, and the second inverter is included in the third path.

10. The electric tractor according to any one of claims 7 to 9, wherein at least a part of the first path is located below the battery.

11. The electric tractor according to any one of claims 7 to 10, wherein at least a part of the third path is located to the left or right of the battery.

12. The electric tractor according to any one of claims 7 to 11, wherein the circulation direction of the coolant can be changed.

13. An electric tractor comprising a battery, a first motor driven by electric power supplied from the battery, a traveling device driven by the first motor, a first cooling path through which a first coolant circulates, and a second cooling path through which a second coolant circulates, wherein the first motor is included in the first cooling path and the battery is included in the second cooling path.

14. The electric tractor according to claim 13, wherein the first coolant and the second coolant are different types of coolants.

15. The electric tractor according to claim 13 or 14, wherein the second coolant is an insulating oil.

16. The electric tractor according to any one of claims 13 to 15, comprising a first radiator that is included in the first cooling path and cools the first coolant, and a second radiator that is included in the second cooling path and cools the second coolant.

17. The electric tractor according to any one of claims 13 to 16, comprising a second motor driven by electric power supplied from the battery, a transmission unit that transmits the driving force of the second motor to a working device, and a hydraulic pump driven by the second motor, wherein the second motor is included in the first cooling path.

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