electric work vehicle

Abstract

To provide an electric work vehicle capable of realizing long-term work travel and reducing a work load when replacing a battery.SOLUTION: An electric work vehicle includes: a travelable machine body 3; a first battery 20 housed in the machine body 3; a three-point link mechanism T connected to a rear of the machine body 3 so as to be able to swing up and down; a drive device capable of swingably driving the three-point link mechanism T; and a second battery 60 detachably attached to the three-point link mechanism T. The electric work vehicle is configured to be switchable between a lowered state in which the second battery 60 is grounded and an elevated state in which the second battery 60 is elevated above a ground by the swinging drive of the three-point link mechanism T.SELECTED DRAWING: Figure 1

Description

[[Technical Field]]

[0001] The present invention relates to an electric work vehicle that includes a three-point link mechanism and is driven by a motor supplied with power from a battery. [[Background Art]]

[0002] In a conventional electric work vehicle, when attempting to extend the operation time to realize long-hour work traveling using a working device such as a mower unit, it is necessary to provide a complementary battery separate from the main battery, for example, as described in Patent Document 1. [[Prior Art Documents]] [[Patent Documents]]

[0003] [[Patent Document 1]] Japanese Unexamined Patent Publication No. 2019-217900 [[Summary of the Invention]] [[Problem to be Solved by the Invention]]

[0004] However, in a conventional electric work vehicle, when the stored power of both the main battery and the complementary battery is exhausted, work traveling cannot be continued thereafter. Further, for example, when attempting to replace the complementary battery with another charged battery, it is necessary to lift the heavy battery to a high position, which imposes a large work burden when performing battery replacement.

[0005] In view of the above problems, an object of the present invention is to provide an electric work vehicle that can realize long-hour work traveling and reduce the work burden when replacing a battery. [[Means for Solving the Problem]]

[0006] The electric work vehicle of the present invention includes a travelable machine body, a first battery housed in the machine body, and is connected to a rear portion of the machine body so as to be vertically swingable , the work equipment can be connectedThe system comprises a three-point linkage mechanism, a drive device capable of pivoting the three-point linkage mechanism, and a second battery detachably attached to the three-point linkage mechanism. The three-point linkage mechanism comprises a single top link and left and right lower links, the top link and the left and right lower links are provided with mounting portions for supporting the work device, and the second battery is detachably attached to the mounting portions. The three-point linkage mechanism is configured to allow switching between a downward state in which the second battery is grounded and an upward state in which the second battery is raised above ground by the oscillation drive.

[0007] According to this invention, in addition to the first battery, a second battery is provided to supply power to the drive wheels or work equipment of the work vehicle. This makes it possible to achieve longer operating times compared to when only the first battery is provided. Furthermore, since the second battery is detachably mounted on the three-point linkage mechanism, the second battery can be replaced with another charged battery, enabling even longer operating times. In addition, the second battery can be raised to the ground by the oscillating drive of the three-point linkage mechanism, eliminating the need to lift the battery to a high position, thus reducing the workload associated with battery replacement.

[0008] In the present invention, it is preferable that a support mechanism is provided for connecting and supporting the second battery to the aircraft body when the second battery is in the raised state.

[0009] With this configuration, since the second battery is supported by the support mechanism, it becomes possible to more effectively prevent the second battery from falling when it is in an elevated position.

[0010] In the present invention, the aircraft body preferably has a protective frame on the rear portion of the aircraft body, which has left and right vertical frame portions and a horizontal frame portion connecting the upper ends of the left and right vertical frame portions, and the support mechanism preferably consists of two connecting members that connect the left and right vertical frame portions to the left and right side walls of the second battery, respectively.

[0011] With this configuration, the second battery is directly connected to a robust protective frame by connecting members, making it possible to more reliably prevent the second battery from falling or otherwise dropping.

[0012] In the present invention, it is preferable that a switching mechanism is provided for automatically or manually switching between power supply from the first battery and power supply from the second battery.

[0013] This configuration includes a switching mechanism to switch between the first and second batteries. For example, if the charge in the first battery becomes low, it can be switched to the second battery manually or automatically. Therefore, if the power supply from the first battery to the drive wheels or work equipment of the work vehicle is insufficient, power can be supplied from the second battery by switching from the first battery, thereby extending the operating time of the electric work vehicle.

[0014] In the present invention, it is preferable that the switching mechanism is equipped with a switching operation unit for manually switching between power supply from the first battery and power supply from the second battery.

[0015] This configuration allows the operator to switch between supplying power from either the first or second battery, increasing the flexibility in selecting which battery to use.

[0016] In the present invention, it is preferable that the switching mechanism automatically switches to supplying power to the other battery when the remaining charge of one of the first and second batteries that is currently supplying power falls below a certain value.

[0017] With this configuration, when the remaining charge of the currently powered battery falls below a certain level, the battery is automatically switched. This eliminates the need for the operator to manually switch batteries during operation, thus reducing the operator's workload. In the present invention, the rear portion of the aircraft is provided with a roll frame for tipping protection that extends upward so as to surround the upper rear portion of the driver's seat, and the support mechanism preferably connects and supports the second battery to the roll frame when the second battery is in the raised position. In the present invention, the second battery comprises a battery body and a carrier that holds the battery body, and it is preferable that the carrier is equipped with caster wheels. [Brief Description of the Drawings]

[0018] [Figure 1] FIG. 1 is a side view of an electric tractor (in a lowered state). [Figure 2] FIG. 2 is a plan view of the electric tractor. [Figure 3] FIG. 3 is a block diagram showing an electric system of a traveling device and a mower. [Figure 4] FIG. 4 is a side view showing the electric tractor in a raised state. [Figure 5] FIG. 5 is a plan view of an electric tractor according to another embodiment. [Figure 6] FIG. 6 is a side view of an electric tractor according to another embodiment. [Mode for Carrying Out the Invention]

[0019] Modes for carrying out the present invention will be described below with reference to the drawings. In the following description, unless otherwise specified, the direction of arrow F in the drawings is defined as "front", the direction of arrow B is defined as "rear", the direction of arrow L is defined as "left", and the direction of arrow R is defined as "right". Further, the direction of arrow U in the drawings is defined as "up", and the direction of arrow D is defined as "down".

[0020] [Overall Configuration of Tractor] As shown in FIG. 1 and FIG. 2, a body 3 is supported by right and left front wheels 1 (corresponding to the "traveling device" of the present invention) and right and left rear wheels 2 (corresponding to the "traveling device" of the present invention). A bonnet 4 is provided at a front portion of the body 3, and an operation section 5 is provided at a rear portion of the body 3. The operation section 5 is provided with a steering handle 6 for steering the front wheels 1, a driver's seat 7, and a floor 8.

[0021] The body 3 includes, at a rear portion of the body 3, a rollover protection ROPS frame 9 (corresponding to the "protection frame" of the present invention) extending upward to surround an upper rear side of the driver's seat 7. The ROPS frame 9 has a pair of left and right vertical frame portions 9a extending along the vertical direction, and a horizontal frame portion 9b connecting upper ends of the left and right vertical frame portions 9a and extending along the horizontal direction.

[0022] The aircraft body 3 is composed of right and left aircraft frames 10, a mission case 11, etc. The mission case 11 is composed of a front case 12 and a rear case 13 connected together. The right and left aircraft frames 10 are connected to the mission case 11 and are arranged in the front-to-rear direction below the driver's compartment 5. The mission case 11 is located below the driver's seat 7 of the driver's compartment 5.

[0023] The front axle case 14 is supported at the front of the machine frame 10, and the right and left front wheels 1 are supported by the front axle case 14. The right and left rear wheels 2 are supported by the transmission case 11 (rear case 13).

[0024] In this embodiment, a motor unit M, which is a work device and is driven by electricity, is provided below the floor 8.

[0025] [Configuration of the three-point linkage mechanism] As shown in Figures 1 and 2, a three-point linkage mechanism T is connected to the rear of the aircraft 3. The three-point linkage mechanism T comprises a single top link 15 and left and right lower links 16.

[0026] The top link 15 and the right and left lower links 16 are mounted on the rear of the transmission case 11 (rear case 13) so as to be able to swing up and down, and working equipment (not shown), such as a rotary tiller, can be connected to the top link 15 and the lower links 16. The lower links 16 are pivotably connected to the rear of the machine frame 10.

[0027] Right and left lift arms 17 are provided at the rear of the transmission case 11 (rear case 13), and a connecting rod 18 is connected between the lift arms 17 and the lower link 16. When the lift arms 17 are swung up and down, the top link 15 and the lower link 16 are raised and lowered.

[0028] Furthermore, a main battery 20 (corresponding to the "first battery" of the present invention) is located inside the bonnet 4. The main battery 20 is covered by the bonnet 4 and housed in the aircraft body 3. Below the main battery 20 is a driving motor 26 (corresponding to the "first electric motor" of the present invention).

[0029] [Transmission case configuration] As shown in Figure 3, a hydrostatic continuously variable transmission (CVT) 28 is housed inside the front case 12 of the transmission case 11, and power from the drive motor 26 is transmitted to the CVT 28 via the transmission shaft 29. The CVT 28 can shift gears indefinitely in both forward and reverse directions and is operated by a gear shift pedal (not shown) located on the floor 8 of the driver's compartment 5.

[0030] The auxiliary transmission 30, the rear differential 31, and the front transmission 32 are housed inside the rear case 13 of the transmission case 11. Power shifted by the continuously variable transmission 28 is transmitted to the auxiliary transmission 30, and then transmitted from the auxiliary transmission 30 to the rear wheels 2 via the rear differential 31.

[0031] Power branched from the auxiliary transmission 30 and the rear differential 31 is transmitted to the front transmission 32, then from the front transmission 32 via the transmission shaft 33 to the front differential 34 housed inside the front axle case 14, and finally from the front differential 34 to the front wheels 1.

[0032] The PTO transmission 35 is housed inside the rear case 13 of the transmission case 11, and the PTO shaft 36 is located at the rear of the rear case 13 of the transmission case 11. When the working device is connected to the top link 15 and the lower link 16, a transmission shaft (not shown) is connected between the PTO shaft 36 and the working device.

[0033] When the power of the travel motor 26 is transmitted to the continuously variable transmission 28 via the transmission shaft 29, the power of the transmission shaft 29 (power that is not shifted by the continuously variable transmission 28) is transmitted to the PTO transmission 35, the shifted power by the PTO transmission 35 is transmitted to the PTO shaft 36, and from the PTO shaft 36 it is transmitted to the work device.

[0034] A single-acting hydraulic cylinder 37 is located at the upper rear of the transmission case 11 (rear case 13), and the lift arm 17 is raised and lowered by the hydraulic cylinder 37.

[0035] A hydraulic pump 38 and a control valve 39 are located inside the rear of the transmission case 11 (rear case 13). Lubricating oil stored in the transmission case 11 (rear case 13) is supplied to the hydraulic pump 38 as hydraulic fluid, and then supplied from the hydraulic pump 38 to the control valve 39.

[0036] The pump motor 40 is located at the upper rear of the transmission case 11 (rear case 13), and the hydraulic pump 38 is driven by the pump motor 40. The DC power from the main battery 20 is converted into AC power in the inverter 24 and supplied to the pump motor 40, which then operates.

[0037] The control valve 39 supplies and discharges hydraulic fluid to the hydraulic cylinder 37, which in turn raises and lowers the lift arm 17. The hydraulic fluid discharged from the hydraulic cylinder 37 is then returned to the transmission case 11 (rear case 13) from the control valve 39.

[0038] [Regarding the installation of the battery unit] As shown in Figures 1, 2, and 4, the three-point linkage mechanism T is configured to allow the attachment of an auxiliary battery, which is a battery unit 60 (corresponding to the "second battery" of the present invention).

[0039] The main battery 20 and battery unit 60 supply power to the drive motor 26, pump motor 40, moor unit M, etc.

[0040] The top link 15 and the left and right lower links 16 are provided with mounting portions 50 to which a battery unit 60 can be attached. The mounting portions 50 are provided at the ends of the top link 15 and the left and right lower links 16 that are opposite to the side connected to the machine body 3. The ends of the left and right lower links 16 are provided with holes 50a that can hold the battery unit 60 as mounting portions 50, and the end of the top link 15 is provided with holes 50b that can hold the battery unit 60 as mounting portions 50. Note that the mounting portions 50 may utilize the configuration already provided in the three-point linkage mechanism T for supporting work implements, etc.

[0041] The battery unit 60 includes a battery body 61, a carrier 62 that holds the battery body 61, and a mounting portion 63 provided on the carrier 62 for detachably attaching the battery unit 60 to the three-point linkage mechanism T.

[0042] The carrier 62 is equipped with right and left shoes 64 facing downwards at the front lower part of the battery unit 60, and large-diameter caster wheels 65 are provided as right and left caster wheels at the right and left ends, respectively, of the rear lower part of the battery unit 60. The battery unit 60 is configured to be transportable without the need for other loading platforms, etc., thanks to the large-diameter caster wheels 65.

[0043] The mounting portion 63 includes a lateral mounting portion 63a provided on the lower part of the left and right front walls of the battery unit 60 and protruding forward, and a front mounting portion 63b provided on the upper part of the front wall of the battery unit 60.

[0044] When attaching the battery unit 60 to the three-point linkage mechanism T, the battery unit 60 is held in place by the three-point linkage mechanism T by inserting the pin P through the hole provided in the lateral mounting portion 63a and the hole 50a at the end of the lower link 16, and further inserting the pin P through the hole provided in the front mounting portion 63b and the hole 50b at the end of the top link 15. Alternatively, a snap pin may be used to secure the pin P and prevent it from coming loose.

[0045] The lift arm 17 is configured to swing up and down based on the drive of the pump motor 40, which is the drive device. The lower link 16 swings up and down in conjunction with the up and down swing of the lift arm 17. The top link 15, which is connected to the battery unit 60, also swings up and down in conjunction with the up and down swing of the lower link 16. The battery unit 60 is connected to the top link 15 and the lower link 16 so as to be able to swing relative to each other, and the battery unit 60 moves up and down in conjunction with the up and down swing of the top link 15 and the lower link 16, respectively. With these configurations, the three-point linkage mechanism T is configured to swing up and down.

[0046] When the operator operates the height setting lever (not shown), the pump motor 40 drives the lift arm 17 to swing, causing the battery unit 60 to move up and down. In this way, the swinging drive of the three-point linkage mechanism T allows switching between a lowered state where the battery unit 60 touches the ground, as shown in Figure 1, and an elevated state where the battery unit 60 rises above the ground, as shown in Figure 4.

[0047] By raising the battery unit 60, the tractor can operate without the battery unit 60 touching the ground. In addition, since the battery unit 60 is not touching the rear of the machine body 3 when raised, it can also act as a counterweight. Furthermore, even when the battery unit 60 remains in the lowered position, the shoe 64 does not touch the ground, and only the large-diameter caster wheel 65 touches the ground, making it possible to operate the machine while towing the battery unit 60.

[0048] As shown in Figure 4, the LOBS frame 9 is equipped with a support mechanism 52 that connects and supports the battery unit 60 to the aircraft body 3 when the battery unit 60 is in the raised position. The support mechanism 52 comprises an arm member 52a attached to the aircraft body 3 and a holding part 52b provided on the top link 15 and connected to the end of the arm member 52a opposite to the side attached to the LOBS frame 9. There are various ways to connect the arm member 52a and the holding part 52b, but for example, the end of the arm member 52a is bent into an L-shape to form a hook shape, and the end is inserted into a hole formed in the holding part 52b to connect them. By connecting the arm member 52a and the holding part 52b, the battery unit 60 is connected and supported to the aircraft body 3 via the support mechanism 52 and the top link 15.

[0049] As shown in Figures 1 and 4, when the operator attaches the battery unit 60 to the three-point linkage mechanism T, the operator connects the harness 53 to the battery body 61 of the battery unit 60. As shown in Figure 3, the main battery 20 and the battery unit 60 are connected to each other via a switching mechanism 54 so that they can be switched automatically or manually. The battery unit 60 is connected to the switching mechanism 54 via the harness 53. By switching via the switching mechanism 54, the main battery 20 or the battery unit 60 is connected to the drive motor 26 and the pump motor 40. As shown in Figure 3, the switching mechanism 54 is equipped with a switching operation unit 55 for manually switching between power supply from the main battery 20 and power supply from the battery unit 60. The switching operation unit 55 may be configured as, for example, a seesaw switch and be provided in the driver's unit 5, but is not limited to this configuration; it may also be configured as a radio switch or the like, and may be provided in a location other than the driver's unit 5.

[0050] Furthermore, it is preferable that the switching mechanism 54 controls the amount of power supplied to the motor from the main battery 20 and the amount of power supplied to the motor from the battery unit 60 to be approximately the same. In this case, the driving motor 26 and the pump motor 40 are driven smoothly without being affected by fluctuations in power supply before and after switching.

[0051] [Another embodiment] The following are examples of alternative embodiments that modify the above embodiments.

[0052] (1) In the above embodiment, a configuration comprising one main battery 20 and one battery unit 60 was described as an example, but the present invention is not limited to the above embodiment, and the main battery 20 and battery unit 60 may each be provided in multiple quantities.

[0053] (2) In the above embodiment, the battery unit 60 is provided with a battery body 61 and a carrier 62 that holds the battery body 61, and the carrier 62 is provided with a mounting portion 63, a shoe 64, and a large-diameter caster wheel 65. However, the present invention is not limited to the above embodiment, and the battery body 61 may be directly provided with the mounting portion 63.

[0054] (3) In the above embodiment, a configuration in which the support mechanism 52 is provided was described as an example, but the present invention is not limited to the above embodiment, and a configuration without the support mechanism 52 may also be provided.

[0055] (4) In the above embodiment, the support mechanism 52 was described as being composed of an arm member 52a and a holding part 52b, but the present invention is not limited to the above embodiment. For example, as shown in Figures 5 and 6, the support mechanism 52 may be composed of two connecting frames 52c (corresponding to the "connecting member" of the present invention) that connect the left and right vertical frame parts 9a and the left and right side walls 60a of the battery unit 60, respectively. In this case, there are various methods for connecting the left and right vertical frame parts 9a and the connecting frames 52c, and for connecting the left and right side walls 60a of the battery unit 60 and the connecting frames 52c. For example, the left and right vertical frame parts 9a and the left and right side walls 60a of the battery unit 60 and the connecting frames 52c may be connected using screws 52d that are inserted through holes (not shown) formed in the connecting frames 52c, but the invention is not limited to this. Furthermore, the support mechanism 52 may be composed of an arm member 52a, a holding part 52b and two connecting frames 52c. In Figures 5 and 6, components similar to those in the above embodiment are denoted by the same reference numerals.

[0056] (5) In the above embodiment, a configuration in which a switching operation unit 55 is provided was described as an example, but the present invention is not limited to the above embodiment, and a configuration without a switching operation unit 55 is also possible. In this case, the switching mechanism 54 may be configured to automatically switch to supplying power from the other battery when the remaining charge of one of the batteries currently supplying power, the main battery 20 and the battery unit 60, falls below a certain value.

[0057] (6) In the above embodiment, a configuration in which the harness 53 is connected to the battery body 61 of the battery unit 60 was described as an example, but the present invention is not limited to the above embodiment, and the harness 53 may be connected to the carrier 62, and the battery body 61 and the switching mechanism 54 may be connected via the carrier 62.

[0058] (7) In the above embodiment, the top link 15 was described as being provided on the arm member 52a as an example, but the present invention is not limited to the above embodiment, and for example, the arm member 52a may be provided on the carrier 62 of the battery unit 60.

[0059] Furthermore, the configurations disclosed in the above embodiments (including other embodiments, the same applies hereinafter) can be applied in combination with configurations disclosed in other embodiments, as long as no inconsistencies arise. In addition, the embodiments disclosed herein are illustrative, and the embodiments of the present invention are not limited thereto, and can be modified as appropriate without departing from the object of the present invention. [Industrial applicability]

[0060] This invention is applicable to electric work vehicles equipped with a three-point linkage mechanism and driven by a motor powered by a battery. [Explanation of Symbols]

[0061] 3: Aircraft 20: Main battery (first battery) 40: Pump motor (drive unit) 52:Support mechanism 54: Switching mechanism 55: Switching operation unit 60: Battery unit (second battery) T: Three-point linkage mechanism

Claims

1. A mobile aircraft, The first battery housed in the aforementioned aircraft, A three-point linkage mechanism is connected to the rear of the aforementioned machine so as to be able to swing up and down, and to which a work device can be attached, The three-point linkage mechanism is driven by a drive device capable of swinging, The three-point linkage mechanism is equipped with a second battery that is detachably attached to the aforementioned three-point linkage mechanism, The aforementioned three-point linkage mechanism comprises a single top link and left and right lower links. The top link and the left and right lower links are provided with mounting portions for supporting the working device. The second battery is detachably attached to the mounting portion. An electric work vehicle configured to be switchable between a lowered state in which the second battery is grounded and an elevated state in which the second battery is raised above ground by the swinging drive of the three-point linkage mechanism.

2. The electric work vehicle according to claim 1, wherein a support mechanism is provided for connecting and supporting the second battery to the machine body when the second battery is in the raised state.

3. The electric work vehicle according to claim 1 or 2, further comprising a switching mechanism for automatically or manually switching between power supply from the first battery and power supply from the second battery.

4. The electric work vehicle according to claim 3, wherein the switching mechanism is provided with a switching operation unit for manually switching between power supply from the first battery and power supply from the second battery.

5. The electric work vehicle according to claim 3, wherein the switching mechanism automatically switches to supplying power to the other battery when the remaining charge of one of the first and second batteries that is currently supplying power falls below a certain value.

6. The rear portion of the aircraft is provided with a rollover protection frame that extends upward so as to surround the upper rear portion of the driver's seat, The electric work vehicle according to claim 2, wherein the support mechanism connects and supports the second battery to the lops frame when the second battery is in the raised state.

7. The second battery comprises a battery body and a carrier for holding the battery body, The electric work vehicle according to claim 1, wherein the carrier is equipped with caster wheels.

Images