Electric work vehicle

Abstract

To provide an electric work vehicle in which an air suction port and an air ejection port of a cooling fan are properly arranged.SOLUTION: An electric work vehicle is provided with: an operation region 5 positioned at a rear part in a longitudinal direction of a vehicle body in a frame structure constituting the vehicle body; a power region 4 positioned at a front part in the longitudinal direction of the vehicle body in the frame structure; a battery 27 arranged in the power region; an electric motor 29 for running, arranged in an air circulation space 41 formed across a length in the longitudinal direction of the vehicle body of the battery 27 in the power region, which is supplied with electricity from the battery 27; an air suction port 44 formed at a rear end region 41r in the air circulation space 41; an air ejection port 45 formed at a front end region 41f in the air circulation space 41; and a cooling fan 32 provided in the vicinity of the air ejection port 45.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a cooling structure for an electric work vehicle that includes a battery and an electric motor for traveling that is powered by the battery. [Background technology]

[0002] In the electric work vehicle according to Patent Document 1, a cooling fan is disposed at the front of the vehicle body, and part of the cooling air from the cooling fan flows toward the battery, and another part flows toward a ventilation space formed between the vehicle body frame and the battery. Furthermore, an inlet portion that takes in air from the outside is provided on the front surface of the cover member that houses the cooling fan and the battery, and an exhaust portion that exhausts the air inside the cover member to the outside is provided on the side of the cover member that faces the lateral side of the battery. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2021-000953 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the electric work vehicle of Patent Document 1, the cooling air intake (inlet) for the cooling fan and the exhaust (exhaust) of the cooling air generated by the cooling fan are located close to each other, and the warm air coming out of the exhaust is taken in again through the intake, which may reduce the cooling performance. Furthermore, since the cooling air intake is located in the front end area of ​​the work vehicle, dust and grass clippings are likely to be taken in, and even if a dustproof net is installed, the dustproof net is likely to become clogged, and in either case, a decrease in cooling performance is unavoidable.

[0005] In view of the above circumstances, an object of the present invention is to provide an electric work vehicle in which the air inlet and air outlet of the cooling fan are appropriately positioned. [Means for solving the problem]

[0006] The electric work vehicle according to the present invention comprises a frame structure which constitutes a vehicle body, a driving area located in the rear part of the frame structure in the fore-and-aft direction of the vehicle body, a power area located in the front part of the frame structure in the fore-and-aft direction of the vehicle body, a battery arranged within the power area, a traveling electric motor which is arranged in an air circulation space formed within the power area over the length of the battery in the fore-and-aft direction of the vehicle body and is powered by the battery, an air intake port provided in the rear end region of the air circulation space, an air exhaust port provided in the front end region of the air circulation space, and a cooling fan provided in the vicinity of the air exhaust port.

[0007] According to this configuration, an air flow space is formed over the length of the battery in the vehicle body in the front-rear direction, and an air intake is provided in the rear end region of the air flow space and an air exhaust is provided in the front end region of the air flow space to circulate air through the air flow space using a cooling fan. This ensures a sufficient distance between the air intake and the air exhaust, and suppresses a decrease in cooling performance caused by the warm air leaving the air exhaust being taken in again through the air intake. Note that the vicinity of the air exhaust here includes the air exhaust itself, and the cooling fan may be provided directly at the air exhaust.

[0008] In the present invention, the air intake is disposed to face the driving area. In order to ensure the driver's comfortable living space as much as possible, the driving area is designed to prevent hot air, dust, grass clippings, etc. from blowing in. As a result, the possibility of hot air, dust, grass clippings, etc. blowing in the air intake facing the driving area is relatively small, and fresh air suitable for cooling can be drawn in.

[0009] When a panel that creates a boundary surface with the outside in the rear end region of the air circulation space is arranged in the operating area, it is advantageous to provide an air intake port in the operating area panel, since the panel is designed to prevent hot air, dust, grass clippings, etc. from being blown in as much as possible. For this reason, the present invention proposes that a panel that forms the rear end surface of the air circulation space be arranged in the rear end region of the air circulation space, and that the air intake port be provided in the panel.

[0010] In a preferred embodiment of the present invention, the air intake is at least partially covered by a mesh provided on the panel so that even if foreign matter such as dust or grass clippings gets into the air intake, the foreign matter will not enter the air flow space.

[0011] Because the steering wheel faces the driver and is disposed close to the driver, the area around the steering wheel is designed to allow good ventilation and to minimize the accumulation of hot air, dust, grass clippings, etc. For this reason, if the panel on which the air intake is provided is disposed below and in front of the steering wheel, there is an advantage in that there is a reduced possibility of hot air, dust, grass clippings, etc. being blown into the air intake.

[0012] In one embodiment of the present invention, a floor panel is laid in the driving area, and the air intake is located above the floor panel. The floor panel prevents hot air, dust, grass clippings, etc. from rising from the ground into the driving area, so if the air intake is located above the floor panel, hot air, dust, grass clippings, etc. are also prevented from entering the air intake.

[0013] In one embodiment of the present invention, the height of the air outlet from the ground is configured to be lower than the height of the air inlet from the ground, which reduces the possibility that the cooling air that has been warmed in the air circulation space and discharged from the air outlet will be sucked back in through the air inlet.

[0014] The inverter that provides drive current to the electric motor for driving is also a heat generating body and requires cooling. For this reason, in the present invention, the inverter that supplies power to the electric motor for driving using power from the battery is disposed in the air flow space. This allows the battery, the electric motor for driving, and the inverter to be efficiently cooled by the cooling air from the same cooling fan. [Brief description of the drawings]

[0015] [Figure 1] FIG. [Diagram 2] FIG. 2 is a left side view in vertical section showing the arrangement of components of the power system. [Diagram 3] 4 is a perspective view of the lower cover from diagonally below. FIG. [Figure 4] FIG. 4 is a schematic diagram showing the flow of cooling air. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] The embodiment of the present invention will be described with reference to the drawings. In the following description, unless otherwise specified, the direction of the arrow U shown in Figures 1, 2, and 3 is "up", the direction of the arrow D is "down", the direction of the arrow F is "front", and the direction of the arrow B is "rear". The direction perpendicular to the arrows U and F, that is, the vertical direction to the paper surface of Figures 1, 2, and 3, is the "left-right direction".

[0017] An embodiment of an electric work vehicle (hereinafter, simply referred to as a work vehicle) will be described with reference to Figs. 1 and 2. In this embodiment, the work vehicle is an electric tractor. Right and left front wheels 1 and right and left rear wheels 2 of the work vehicle are attached to a vehicle body 3 formed of a frame structure. A bonnet 40 is provided at the front of the vehicle body 3, and a driving area 5 is located at the rear of the vehicle body 3 in the vehicle front-rear direction. A steering wheel 6 for steering the front wheels 1, a driver's seat 7, and a rope frame 9 are provided in the driving area 5. The steering wheel 6 is supported by a handle post (not shown). The handle post is covered by a panel 42 arranged at the front lower part of the steering wheel 6. This panel 42 is located in front of the driver's seat 7, so hereinafter, the panel 42 will be referred to as a front panel 42. The front panel 42 extends to a floor panel 43 that forms the floor surface of the driving area 5. The upper part of the front panel 42 is formed as a meter panel, and a speedometer and a fuel gauge are arranged therein. Furthermore, a group of operating tools 10 consisting of a plurality of manual operating tools for controlling the travel speed of the work vehicle and the working devices provided on the work vehicle are arranged around the front panel 42 and the driver's seat 7.

[0018] 1 and 2, a transmission 12 having a continuously variable transmission 11 is attached to the rear portion of the vehicle body 3 below the driver's seat 7, and a front axle case 8 is attached to the front portion of the vehicle body 3. The front wheels 1 are supported by the front axle case 8, and the rear wheels 2 are supported by a transmission case 13 that houses the transmission 12.

[0019] As shown in Fig. 2, a power area 4 covered by a bonnet 40 is located in the front portion of the vehicle body 3 in the vehicle front-rear direction. A battery 27, an inverter 28, a traveling electric motor 29, and a cooling fan 32 incorporating a fan motor 33 are arranged in the power area 4. A subframe structure 50 that creates a rectangular space above the pair of left and right front and rear frames that make up the vehicle body 3 is supported by the front and rear frames. The battery 27 is arranged in the space created by the subframe structure 50 and is fixed to the subframe structure 50. As a result, the battery 27 is located above the pair of left and right front and rear frames that make up the vehicle body 3.

[0020] As shown in Figures 1 and 2, a lifting link mechanism 14 is connected to the rear of the transmission case 13 so as to be able to swing up and down. Various working implements (not shown), such as cultivators, can be attached to the lifting link mechanism 14. The lifting link mechanism 14 is operated to swing up and down by the lifting cylinder 15, whereby the working implement is lifted and lowered. A hydraulic pump 35 and a hydraulic pump motor 36 that drives the hydraulic pump 35 are attached to the upper part of the transmission case 13. The hydraulic pump motor 36 is also powered by the battery 27. The lifting and lowering operation of the lifting cylinder 15 is driven by hydraulic oil from the hydraulic pump 35.

[0021] 1 shows a front loader 17, which is one of the working devices attached to the front of the vehicle body 3. The front loader 17 has a base 18, a boom 19, a bucket 20, etc. The boom 19 and the bucket 20 are actuated by a hydraulic cylinder to which hydraulic oil is supplied from a hydraulic pump 35.

[0022] 1, a mid-mounted mower deck 24 is disposed between the front wheels 1 and the rear wheels 2 and is attached to the vehicle body 3 so as to be movable up and down. The mower deck 24 has three rotating blades (not shown) that are rotated around an axis that is aligned in the vertical direction and are disposed inside the mower deck 24 so as to be aligned in the horizontal direction, and grass cut by the rotating blades is discharged laterally to the right from a discharge section (not shown) on the right of the mower deck 24.

[0023] 2, the power of the traveling electric motor 29 is transmitted to the continuously variable transmission 11 via a transmission shaft. The continuously variable transmission 11 is configured as a hydrostatic transmission (HST), and is capable of continuously changing the speed between the forward and reverse sides.

[0024] The power changed in speed by the continuously variable transmission 11 is transmitted to the rear wheels 2 via an auxiliary transmission (not shown) and a rear wheel differential (not shown) provided inside the transmission 12. The power branched off just before the rear wheel differential is transmitted via a transmission shaft to a front wheel differential (not shown) provided inside the front axle case 8, and then transmitted from the front wheel differential to the front wheels 1.

[0025] The front PTO shaft 37 is provided facing forward at the bottom of the front wall of the transmission 12, and the rear PTO shaft 38 is provided facing backward at the rear part of the transmission 12. Of the power transmitted by the transmission shaft, power that is not subjected to speed change by the continuously variable transmission 11 is transmitted to the front PTO shaft 37 and the rear PTO shaft 38.

[0026] The power of the front PTO shaft 37 is transmitted to the mower deck 24 via a transmission shaft (not shown), thereby driving the rotating blades. The power of the rear PTO shaft 38 is transmitted to a working device attached to the lifting link mechanism 14 via a transmission shaft (not shown).

[0027] In this embodiment, an air flow space 41 is formed between the pair of left and right front and rear frames below the bottom surface of the battery 27, over the length of the battery 27 in the vehicle body front-rear direction. If there is space on the sides of the battery 27, the sides of the bottom surface of the battery 27 are also used as the air flow space 41. The inverter 28 and the electric motor 29 for traveling are disposed in the air flow space 41. The electric motor 29 for traveling and the inverter 28 are supported by the vehicle body 3 so that the electric motor 29 for traveling is located behind the inverter 28. A lower cover 30 is provided below the inverter 28 and the electric motor 29 for traveling so as to cover the inverter 28 and the electric motor 29 from below. The electric motor 29 for traveling rotates by a drive current generated by the inverter 28 from the electric power from the battery 27.

[0028] In order to form the air flow space 41, the lower cover 30 shown in FIG. 3 is disposed in the bottom surface area of ​​the battery 27. The lower cover 30 has four side walls, namely, a front side wall 30f, a left side wall 30l, a right side wall 30r, and a rear side wall 30b, whose upper portions extend in the extension direction, while their lower portions are bent inwardly with respect to the upper portions. As a result, the open area of ​​the bottom surface is smaller than the open area of ​​the top surface. The upper portion of the front side wall 30f is provided with holes aligned on the left and right, and the lower portion of the front side wall 30f is provided with one hole. Each hole has a circular cross section and is used as an air exhaust port 45 and a cooling fan mounting port. That is, in this embodiment, three cooling fans 32 are disposed in the front end region 41f. The upper portion of the rear side wall 30b is open to allow the transmission shaft extending rearward from the output shaft of the traveling electric motor 29 to pass through, as shown in FIG. 2.

[0029] As shown in FIG. 4, three vertically aligned air intake ports 44 are provided in the rear end region 41r of the air circulation space 41 in which the inverter 28 and the electric motor 29 for traveling are arranged, and an air exhaust port 45 is provided in the front end region 41f of the air circulation space 41. In this embodiment, the air circulation space 41 is extended from the front end lower portion of the power area 4 to the inside of the front panel 42, so that the surface of the front panel 42 facing the driver's seat 7 forms the rear end surface in the rear end region 41r of the air circulation space 41. Furthermore, the front end lower portion of the power area 4 forms the front end region 41f of the air circulation space 41. Specifically, the air intake port 44 is provided in the front panel 42 corresponding to the rear end region 41r of the air circulation space 41, and the air exhaust port 45 is provided in the front wall of the lower cover 30 corresponding to the front end region 41f of the air circulation space 41. The three air intake ports 44 are located above the floor panel 43, and each air intake port 44 has a mesh body 44m attached thereto, and the air exhaust port 45 also has a mesh body 45m attached thereto.

[0030] The cooling fan 32, which creates a cooling air flow that flows through the air circulation space 41, is provided near the air outlet 45. In this embodiment, the cooling fan 32 is attached to three holes provided in the lower cover 30 in which the air outlet 45 is formed. As the cooling fan 32 rotates, outside air as cooling air passes through the air circulation space 41 from the air intake 44 and is discharged from the air outlet 45. The inverter 28 and the electric motor 29 for traveling are cooled by this cooling air flow. At the same time, the battery 27 is also cooled.

[0031] [Another embodiment] (1) In the above-described embodiment, the fan motor 33 is incorporated in the housing of the cooling fan 32. Alternatively, the fan motor 33 may be separated from the cooling fan 32, and a belt transmission mechanism or a gear transmission mechanism may be used to provide power from the fan motor 33 to the cooling fan 32. In this case, it is also possible for one fan motor 33 to provide power to multiple fan motors 33.

[0032] (2) In the above embodiment, the battery 27 has a single structure, but it is also possible to divide it into multiple units and place them in the power area 4. In this case, the space between two batteries 27 arranged in the transverse direction of the vehicle body can be used as at least a part of the air flow space 41.

[0033] (3) The air exhaust port 45 may be formed in a location other than the front end region 41f of the air flow space 41 so as to exhaust air from the air flow space 41 downward or laterally, for example.

[0034] In addition, the configurations disclosed in the above-mentioned embodiments (including other embodiments, the same applies below) can be applied in combination with configurations disclosed in other embodiments, provided that no contradiction arises. Furthermore, the embodiments disclosed in this specification are illustrative, and the embodiments of the present invention are not limited thereto, and can be appropriately modified within the scope that does not deviate from the purpose of the present invention. [Industrial Applicability]

[0035] The present invention is applicable to an electric work vehicle that uses a cooling fan to cool power equipment. [Explanation of symbols]

[0036] 3: Body 4: Power area 5: Operating area 6: Steering wheel 7: Driver's seat 10: Operating tools 11: Continuously variable transmission 12: Transmission 14: Lifting link mechanism 17: Front loader 24: Moore Deck 27: Battery 28: Inverter 29: Electric motor for driving 30: Lower cover 32: Cooling fan 33: Fan motor 37: Front PTO axis 38: Rear PTO axis 40: Bonnet 41: Air circulation space 41f: Front end area 41r: Rear end area 42: Panel (front panel) 43: Floor panel 44: Air intake 45: Air exhaust port 50: Subframe structure

Claims

1. A frame structure constituting a vehicle body; A driving area located at a rear portion of the frame structure in a vehicle front-rear direction; a power area located at a front portion of the frame structure in the vehicle front-rear direction; a battery disposed within the power area; an electric motor for traveling that is disposed in an air flow space formed within the power area and extending over the length of the battery in the vehicle body front-rear direction, and that is supplied with power from the battery; an air intake port provided in a rear end region of the air flow space; an air exhaust port provided in a front end region of the air flow space; a cooling fan provided near the air outlet; An electric work vehicle equipped with

2. The electric work vehicle according to claim 1 , wherein the air intake is disposed to face the driving area.

3. 2. The electric work vehicle according to claim 1, wherein a panel that forms a rear end face of the air circulation space is disposed in the rear end region of the air circulation space, and the air intake port is provided on the panel.

4. 4. The electric work vehicle according to claim 3, wherein the air inlet is at least partially covered by a mesh provided on the panel.

5. 4. The electric work vehicle according to claim 3, wherein the panel is disposed below and in front of the steering wheel.

6. 2. The electric work vehicle according to claim 1, wherein a floor panel is laid in the driving area, and the air intake is located above the floor panel.

7. The electric work vehicle according to claim 1 , wherein the height of the air outlet from the ground is lower than the height of the air inlet from the ground.

8. 2. The electric work vehicle according to claim 1, wherein an inverter that supplies power to the electric motor for traveling using power from the battery is disposed in the air circulation space.

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