Electric work vehicle

Abstract

To provide an electric work vehicle enabling an electric motor and a power control unit to be connected while preventing a housing from being increased in size.SOLUTION: An electric work vehicle is provided with a housing disposed vertically above a traveling vehicle body and adapted to house electric devices. A power control device and an electric motor are disposed outside the housing and connected to each other by a high-voltage cable for power transmission, and thus waterproof performance of the electrical devices is ensured. In addition, the power control device and the electric motor can be directly connected by the high-voltage cable without passing through the housing. Therefore, the electric motor and the power control device can be connected while preventing the housing from being increased in size.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a power-operated work vehicle equipped with a power control device for controlling power to an electric motor.

Background Art

[0002] A power-operated work vehicle including one or more electric motors, a travelable vehicle body portion, a power transmission portion attached to the vehicle body portion for transmitting power from the electric motor, a battery, and a power control device for controlling power transmitted between the battery and the electric motor is well known. For example, the electric tractor described in Patent Document 1 is such a vehicle.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, when an electric device is mounted on a power-operated work vehicle, for example, it is conceivable to house the electric device in a housing. The electric device is waterproofed by being mounted inside the housing. At this time, since the housing is sealed for waterproofing, structures such as cables and connectors for connecting the inside and outside of the housing and holes and grommets for communicating the inside and outside of the housing are required. On the other hand, since the electric motor is mechanically connected to the power transmission portion to transmit power to the power transmission portion and the vehicle body portion, it is disposed outside the housing. Therefore, if the power control device is housed in the housing, a structure for penetrating a cable or the like for connecting the electric motor and the power control device from the inside to the outside of the housing while maintaining waterproof performance is required. When the electric motor and the power control device are connected by a high-voltage cable that is thicker and more rigid than a low-voltage cable, the structure for penetrating the housing may be enlarged.

[0005] The present invention has been made against the background of the above circumstances, and an object thereof is to provide an electric work vehicle capable of connecting an electric motor and a power control device while suppressing an increase in the size of the housing.

Means for Solving the Problems

[0006] The gist of the first invention is as follows: (a) an electric work vehicle including one or more electric motors, a travelable traveling vehicle body part, a power transmission part attached to the traveling vehicle body part for transmitting power from the electric motor, a battery, and a power control device for controlling power transmitted between the battery and the electric motor, (b) electrical equipment, and (c) a housing for housing the electrical equipment, which is disposed above the traveling vehicle body part in the vertical direction, and (d) the power control device and the electric motor are disposed outside the housing and connected by a high-voltage cable for power transmission.

Effects of the Invention

[0007] According to the first invention, a housing for housing electrical equipment is provided, which is disposed above the traveling vehicle body part in the vertical direction. The power control device and the electric motor are disposed outside the housing and connected by a high-voltage cable for power transmission. Thereby, the waterproof performance of the electrical equipment is ensured. Also, the power control device and the electric motor can be directly connected by a high-voltage cable without penetrating the housing. Therefore, the electric motor and the power control device can be connected while suppressing an increase in the size of the housing.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Mode for Carrying Out the Invention

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

Embodiment

[0010] FIG. 1 is a diagram for explaining an example of a schematic configuration of an electric tractor 10 which is an example of an electric work vehicle to which the present invention is applied. (a) in FIG. 1 is a left side view of the electric tractor 10. (b) in FIG. 1 is a top view of the electric tractor 10. In addition, in (b) of FIG. 1, for convenience, a high-voltage battery 40 described later is removed.

[0011] In FIG. 1, the electric tractor 10 includes a plurality of electric motors MG, a travelable traveling vehicle body portion 20, a power transmission portion 30, a high-voltage battery 40, and a power control unit PCU. The electric tractor 10 is, for example, an agricultural tractor.

[0012] The traveling vehicle body portion 20 includes a tractor vehicle 22 and a vehicle frame 24. The tractor vehicle 22 is, for example, a known crawler capable of traveling in a field. The vehicle frame 24 is a vehicle body fixed to the tractor vehicle 22. The electric tractor 10 is, for example, a full crawler tractor.

[0013] The power transmission portion 30 is attached to the traveling vehicle body portion 20 and includes a transmission 32 for traveling and turning and a transmission 34 for work. The electric motor MG includes a traveling electric motor MGc, a turning electric motor MGt, and a work electric motor MGw.

[0014] The traveling electric motor MGc and the turning electric motor MGt are each connected to the transmission 32 for traveling and turning so as to be able to transmit power. The transmission 32 for traveling and turning is connected to the tractor vehicle 22 so as to be able to transmit power. The transmission 32 for traveling and turning transmits each of the power from the traveling electric motor MGc and the power from the turning electric motor MGt to the tractor vehicle 22.

[0015] The working motor MGw is connected to the working transmission 34 so as to be able to transmit power thereto. The working transmission 34 is attached to the vehicle frame 24, and a working machine (not shown) is attached thereto as necessary. This working machine is, for example, a tiller, a plow, a fertilizer applicator, a lawn mower, a seeder, or the like. The working transmission 34 transmits the power from the working motor MGw to the working machine.

[0016] The high-voltage battery 40 is a chargeable and dischargeable DC power source, and is a known secondary battery such as a nickel-metal hydride secondary battery or a lithium-ion battery. The high-voltage battery 40 is a battery that supplies power to the motor MG. The power control unit PCU is a device that controls the power transmitted between the high-voltage battery 40 and the motor MG.

[0017] The electric tractor 10 further includes an electric device 50 and a waterproof box 60 that houses the electric device 50. The electric device 50 requires waterproofing. The waterproof box 60 is a housing disposed above the traveling vehicle body portion 20, particularly above the tractor vehicle 22 in the vertical direction. The waterproof box 60 has waterproof performance.

[0018] FIG. 2 is a diagram for explaining an example of the arrangement of the waterproof box 60, the power control unit PCU, and the like. FIG. 3 is a diagram for explaining an example of the electrical configuration related to the electric device 50, the motor MG, and the like.

[0019] In FIGS. 2 and 3, the electrical equipment 50 is electrical and electronic equipment excluding the electrical equipment that serves as a power source such as the motor MG. For example, the electrical equipment 50 includes an AC charger 52, a branch box 54, a DC-DC converter 56, an AC inverter 58, and an electric motor control device ECU. Further, the electric tractor 10 further includes a charging cable 70, a charging inlet 72, a power supply cable 74, a power supply outlet 76, an auxiliary battery 78, a high-voltage power transmission cable 80, a low-voltage power transmission cable 82, and a low-voltage communication cable 84, etc. The high-voltage power transmission cable 80 is various high-voltage power transmission cables. The low-voltage power transmission cable 82 is various low-voltage power transmission cables. The low-voltage communication cable 84 is various low-voltage communication cables.

[0020] The high-voltage battery 40 is connected to each of the AC charger 52, the power control device PCU, and the branch box 54 via the high-voltage power transmission cable 80. The high-voltage power transmission cable 80 includes a high-voltage cable 80a, a high-voltage cable 80b, and a high-voltage cable 80c. The high-voltage cable 80a is a cable connecting the high-voltage battery 40 and the AC charger 52. The high-voltage cable 80b is a cable connecting the high-voltage battery 40 and the power control device PCU. The high-voltage cable 80c is a cable connecting the high-voltage battery 40 and the branch box 54.

[0021] The AC charger 52 is connected to the charging inlet 72 via the charging cable 70. The charging inlet 72 is provided on the vehicle frame 24 so as to be connectable to a charging connector 104 of an external charging cable 102 connected to an external power source 100 which is a power source outside the electric tractor 10. The charging inlet 72 is a terminal for inputting the power supplied from the external power source 100 when connected to the charging connector 104, and is a charging port connected to the external power source 100. The charging cable 70 is also a kind of high-voltage cable.

[0022] The AC charger 52 is a charger that charges the high-voltage battery 40 with the power supplied from the external power source 100. The AC charger 52 converts the alternating current supplied from the external power source 100 into direct current, and boosts the voltage of the external power source 100 to a voltage equivalent to that of the high-voltage battery 40 to charge the high-voltage battery 40.

[0023] From the high-voltage battery 40, the stored power is supplied to the electric motor MG via the power control unit PCU or the like. Also, when the charging connector 104 connected to the external power source 100 is connected to the charging inlet 72, the power from the external power source 100 is supplied to the high-voltage battery 40 via the AC charger 52 or the like. The electric tractor 10 is a tractor capable of charging the high-voltage battery 40 with the power from the external power source 100. The high-voltage battery 40 is a driving battery.

[0024] The power control unit PCU is connected to each of the electric motors MG via the high-voltage power transmission cable 80. The high-voltage power transmission cable 80 includes the high-voltage cable 80d, the high-voltage cable 80e, and the high-voltage cable 80f. The high-voltage cable 80d is a cable connecting the power control unit PCU and the traveling electric motor MGc. The high-voltage cable 80e is a cable connecting the power control unit PCU and the slewing electric motor MGt. The high-voltage cable 80f is a cable connecting the power control unit PCU and the working electric motor MGw.

[0025] The power control unit PCU includes an inverter having switching elements or the like. The power control unit PCU converts the direct current from the high-voltage battery 40 into an alternating current for driving each of the electric motors MG. Incidentally, the power control unit PCU may include a boost converter that boosts the voltage of the high-voltage battery 40 and supplies it to the inverter depending on the voltage of the high-voltage battery 40.

[0026] The branch box 54 is connected to each of the DC-DC converter 56 and the AC inverter 58 via the high-voltage power transmission cable 80. The high-voltage power transmission cable 80 includes the high-voltage cable 80g and the high-voltage cable 80h. The high-voltage cable 80g is a cable that connects the branch box 54 and the DC-DC converter 56. The high-voltage cable 80h is a cable that connects the branch box 54 and the AC inverter 58.

[0027] The branch box 54 supplies the power from the high-voltage battery 40 to each of the DC-DC converter 56 and the AC inverter 58. That is, the DC-DC converter 56 and the AC inverter 58 are each connected to the high-voltage battery 40 via the branch box 54.

[0028] The DC-DC converter 56 is connected to each of the auxiliary battery 78 and the electric motor control device ECU via the low-voltage power transmission cable 82. The DC-DC converter 56 functions as a charging device that steps down the voltage of the high-voltage battery 40 to a voltage equivalent to that of the auxiliary battery 78 to charge the auxiliary battery 78. The DC-DC converter 56 and / or the auxiliary battery 78 supplies the power for operating the auxiliary equipment provided in the electric tractor 10, the electric motor control device ECU, and the like.

[0029] The AC inverter 58 is connected to the power supply outlet 76 via the power supply cable 74. The AC inverter 58 converts the direct current supplied from the high-voltage battery 40 into an alternating current and steps down the voltage of the high-voltage battery 40 to a voltage equivalent to that of, for example, the external power supply 100. The power supply outlet 76 is provided on the vehicle frame 24 so that a plug of an electrical device outside the electric tractor 10 can be connected. The power supply outlet 76 is a terminal for supplying power to an electrical device outside the electric tractor 10 and is a power supply port connected to the external electrical device. The power supply cable 74 is also a type of high-voltage cable.

[0030] The electric motor control device ECU is connected to each of the power control device PCU and the electric motor MG via a low-voltage cable 84 for transmission. The low-voltage cable 84 for transmission includes a low-voltage cable 84a, a low-voltage cable 84b, a low-voltage cable 84c, and a low-voltage cable 84d. The low-voltage cable 84a is a cable that connects the electric motor control device ECU and the power control device PCU. The low-voltage cable 84b is a cable that connects the electric motor control device ECU and the driving electric motor MGc. The low-voltage cable 84c is a cable that connects the electric motor control device ECU and the swivel electric motor MGt. The low-voltage cable 84d is a cable that connects the electric motor control device ECU and the working electric motor MGw.

[0031] The electric motor control device ECU is an electronic control device that outputs a command signal to the power control device PCU via the low-voltage cable 84a to drive the power control device PCU. For example, the electric motor control device ECU outputs a command signal for driving the electric motor MG based on an output requirement value according to the operator's request. Detection signals such as the rotational speed and temperature of each electric motor MG are supplied to the electric motor control device ECU from various sensors provided in the electric motor MG via the low-voltage cable 84b, the low-voltage cable 84c, and the low-voltage cable 84d.

[0032] The electric tractor 10 is equipped with electrical equipment 50 such as an AC charger 52, a branch box 54, a DC / DC converter 56, an AC inverter 58, and an electric motor control device ECU. Therefore, a waterproof box 60 is provided in the electric tractor 10, and the electrical equipment 50 is waterproofed by being installed inside the waterproof box 60. On the other hand, the electric motor MG, which is the prime mover of the electric tractor 10, is mechanically connected to the power transmission unit 30 in order to transmit power to the power transmission unit 30 and the tractor vehicle 22. Therefore, the electric motor MG is disposed outside the waterproof box 60. Also, the electric motor MG is connected to the power control unit PCU by high-voltage cables 80d, 80e, and 80f for power supply. On the other hand, the high-voltage power transmission cable 80 has a thicker wire diameter and higher rigidity compared to the low-voltage power transmission cable 82 and the low-voltage communication cable 84. Also, the connector or terminal block used for the high-voltage power transmission cable 80 is larger than those used for the low-voltage power transmission cable 82 and the low-voltage communication cable 84.

[0033] Here, since the waterproof box 60 is sealed for waterproofing, structures such as the routing of cables and connectors for connecting the inside and outside of the waterproof box 60, and holes and grommets for communicating the inside and outside of the waterproof box 60 are required. Therefore, if the power control unit PCU is housed inside the waterproof box 60, it becomes necessary to install and handle large grommets that penetrate the high-voltage cables 80d, 80e, 80f and the large terminal block from the inside to the outside of the waterproof box 60 while maintaining the waterproof performance. Then, there is a risk that the structure for penetrating the waterproof box 60 will become larger.

[0034] Therefore, in order to connect the electric motor MG and the power control unit PCU while suppressing the increase in size of the waterproof box 60, the power control unit PCU is arranged outside the waterproof box 60, similarly to the electric motor MG (see FIGS. 1 - 3). In the electric tractor 10, the inside of the waterproof box 60 is a waterproof required area (= waterproof required zone) that requires waterproof performance. The electric tractor 10 has a dustproof required (dustproof) area that does not require waterproofing but has dustproof performance. In this embodiment, the dustproof required (dustproof) area is referred to as a dustproof area (= dustproof zone) 90. The dustproof area 90 is provided above the traveling vehicle body part 20, particularly above the tractor vehicle 22 in the vertical direction and adjacent to the waterproof box 60 in the horizontal direction. The power control unit PCU is provided above the traveling vehicle body part 20, particularly above the tractor vehicle 22 in the vertical direction and adjacent to the waterproof box 60 in the horizontal direction. The power control unit PCU has a simple waterproof function by itself and is arranged in the dustproof area 90. Incidentally, the high - voltage battery 40 also has a simple waterproof function by itself, and the area where the high - voltage battery 40 is arranged is also a dustproof area.

[0035] Referring to FIG. 2, among the high - voltage cables, the charging cable 70, the power supply cable 74, and the high - voltage cables 80a (and 80c) are communicated between the inside and the outside of the waterproof box 60 through the high - voltage grommet 86. Among the high - voltage cables, the high - voltage cables 80b, 80d, 80e, and 80f are arranged outside the waterproof box 60. The low - voltage power transmission cable 82 and the low - voltage signal transmission cable 84 are communicated between the inside and the outside of the waterproof box 60 through the low - voltage grommet 88.

[0036] FIG. 4 is a diagram for explaining an example of a panel 92 surrounding the dustproof area 90. FIG. 4(a) is a left - side view of the electric tractor 10. FIG. 4(b) is a top - right - rear view of the electric tractor 10. FIG. 4(c) is a bottom - left - rear view of the electric tractor 10.

[0037] In FIG. 4, the electric tractor 10 includes a panel 92 arranged to surround the dust-proof area 90 (see the wire-mesh part). The panel 92 includes a side panel 92a, a rear panel 92b, and an under panel 92c. The side panel 92a is arranged on the left side in the horizontal direction of the dust-proof area 90. The rear panel 92b is arranged at the rear in the horizontal direction of the dust-proof area 90. The under panel 92c is arranged below the dust-proof area 90 in the vertical direction. The right side and the front in the horizontal direction of the dust-proof area 90 are surrounded by the waterproof box 60. The side panel 92a and the rear panel 92b are panels arranged around the horizontal periphery of the dust-proof area 90 except for the side of the waterproof box 60. The under panel 92c is a panel arranged below the dust-proof area 90 in the vertical direction. The high-voltage battery 40 is arranged adjacent to the power control unit PCU above it in the vertical direction (see FIG. 1). Therefore, the area above the dust-proof area 90 in the vertical direction is surrounded by the high-voltage battery 40. The dust-proof area 90 is surrounded by the panel 92, the waterproof box 60, and the high-voltage battery 40.

[0038] As described above, according to this embodiment, there is provided a waterproof box 60 that houses the electrical equipment 50 and is arranged above the running vehicle body part 20 in the vertical direction. The power control unit PCU and the electric motor MG are arranged outside the waterproof box 60 and are connected by high-voltage cables 80d, 80e, 80f. Thereby, the waterproof performance of the electrical equipment 50 is ensured. Also, the power control unit PCU and the electric motor MG can be directly connected by high-voltage cables without passing through the waterproof box 60. For example, it is not necessary to install a large grommet for passing through the waterproof box 60. Therefore, the electric motor MG and the power control unit PCU can be connected while suppressing the enlargement of the waterproof box 60.

[0039] Further, according to this embodiment, the power control unit PCU is provided above the traveling body portion 20 in the vertical direction and adjacent to the waterproof box 60 in the horizontal direction. Thereby, the cable for connecting the power control unit PCU and the inside of the waterproof box 60 is shortened. Also, a dustproof area 90 is provided above the traveling body portion 20 in the vertical direction and adjacent to the waterproof box 60 in the horizontal direction. The power control unit PCU is disposed in the dustproof area 90. Thereby, the dustproof performance of the power control unit PCU is ensured.

[0040] Further, according to this embodiment, the high-voltage battery 40 is disposed adjacent to the power control unit PCU above it in the vertical direction. An under panel 92c disposed below the dustproof area 90 in the vertical direction and side panels 92a and a rear panel 92b disposed around the dustproof area 90 in the horizontal direction excluding the waterproof box 60 side are provided. Thereby, the dustproof area 90 where the power control unit PCU is disposed, that is, the non-waterproof area, is prevented from being directly hit by mud, water, flying stones, etc.

[0041] Further, according to this embodiment, the motor control unit ECU housed in the waterproof box 60 is connected to each of the power control unit PCU and the motor MG by a low-voltage transmission cable 84. Thereby, the waterproof performance of the motor control unit ECU is ensured. Also, by installing a small low-voltage grommet 88 for penetrating the waterproof box 60, the motor control unit ECU can be connected to each of the power control unit PCU and the motor MG.

[0042] As described above, the embodiments of the present invention have been described in detail based on the drawings, but the present invention is also applicable in other aspects.

[0043] For example, in the foregoing embodiment, a full crawler tractor is exemplified as the electric tractor 10, but it is not limited to this aspect. For example, the electric tractor 10 may be a half crawler tractor, a wheel tractor, or the like.

[0044] In addition, in the above-described embodiment, the electric motors MG are exemplified by the traveling electric motor MGc, the turning electric motor MGt, and the working electric motor MGw. However, the present invention is not limited to this aspect. For example, the electric motor MG may be a single electric motor. In this case, for example, an electric motor connected to the working transmission 34 so as to be capable of power transmission may be provided, and an engine may be provided as a power source connected to the traveling and turning transmission 32 so as to be capable of power transmission. The electric work vehicle may be a tractor including at least a power source including an electric motor.

[0045] Note that the above is merely one embodiment, and the present invention can be implemented in various modified and improved forms based on the knowledge of those skilled in the art.

Explanation of Reference Numerals

[0046] 10: Electric tractor (electric work vehicle) 20: Traveling vehicle body part 30: Power transmission part 40: High-voltage battery (battery) 50: Electrical equipment 60: Waterproof box (housing) 80: High-voltage cable for power transmission (high-voltage cable for power transmission) 84: Low-voltage cable for communication (low-voltage cable for communication) 90: Dust-proof area (dust-proof zone) 92: Panel 92a: Side panel (panel) 92b: Rear panel (panel) 92c: Under panel (panel) ECU: Electric motor control device (electronic control device) MG: Electric motor PCU: Power control device

Claims

1. An electric work vehicle comprising: one or more electric motors; a travelable vehicle body portion; a power transmission portion attached to the vehicle body portion for transmitting power from the electric motors; a battery; and a power control device for controlling power transmitted between the battery and the electric motors, an electrical device, a housing for housing the electrical device, disposed above the vehicle body portion in the vertical direction, further comprising, wherein the power control device and the electric motors are disposed outside the housing and connected by a high-voltage cable for power transmission. The electric work vehicle is characterized by this.

2. The electric work vehicle according to claim 1, wherein the power control device is provided above the vehicle body portion in the vertical direction and adjacent to the housing in the horizontal direction.

3. further comprising a dust-proof area provided above the vehicle body portion in the vertical direction and adjacent to the housing in the horizontal direction, wherein the power control device is disposed in the dust-proof area, wherein the battery is disposed adjacent to the power control device above it in the vertical direction, The electric work vehicle according to claim 2, further comprising panels disposed below the dust-proof area in the vertical direction and around the dust-proof area excluding the side of the housing in the horizontal direction.

4. wherein the electrical device includes an electronic control device for driving the power control device, The electric work vehicle according to claim 1, wherein the electronic control device and the power control device, and the electronic control device and the electric motors are each connected by a low-voltage cable for signal transmission.

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