Work vehicle and method for controlling work vehicle

Abstract

According to the present invention, an electric work vehicle comprises: a travel device; a PTO shaft that supplies power to a work machine; one or more electric motors that drive the travel device and the PTO shaft; a starter switch for activating the work vehicle; a specific mode switch for enabling a specific function in the work vehicle; and a control device that controls the operation of the work vehicle. In a state in which the work vehicle is not activated, the control device activates the work vehicle in response to manipulation of the specific mode switch and starts an operation in a specific mode in which the specific function is enabled.

Description

Work vehicle and method for controlling work vehicle

[0001] The present invention relates to a work vehicle and a method for controlling a work vehicle.

[0002] In the field of automobiles whose main purpose is to move people or objects, electric vehicles (EVs) that generate driving force (traction) for running by an electric motor (hereinafter sometimes simply referred to as "motor") instead of an internal combustion engine are becoming popular.

[0003] On the other hand, in order to realize a decarbonized society, it is required to reduce the amount of carbon dioxide (CO ２ ) emitted by work vehicles such as tractors used in fields. Different from general automobiles, work vehicles such as tractors need to tow a work implement (agricultural implement) to perform agricultural work such as tilling. Therefore, in order to realize the electrification of work vehicles, there are problems to be solved different from the electrification of passenger cars.

[0004] Patent Document 1 discloses an electric tractor that distributes and supplies electric power from a battery to a plurality of electric motors. The electric tractor includes a hydraulic pump, a pump motor, a PTO motor, a traveling motor, a battery, and an electric drive controller. The pump motor is an electric motor that drives the hydraulic pump. The PTO motor is an electric motor that drives the PTO shaft. The traveling motor is an electric motor that drives to run the traveling body. The battery supplies electric power to the pump motor, the PTO motor, and the traveling motor. The electric drive controller controls the distribution of electric power to the pump motor, the PTO motor, and the traveling motor.

[0005] Japanese Unexamined Patent Application Publication No. 2023-66721

[0006] The present invention provides a technology that enables a specific operation such as charging a battery of a work vehicle or finely adjusting the position of the vehicle or the height of the three-point link for smooth attachment of a work implement to the work vehicle to be performed more easily.

[0007] The present disclosure provides the solution means described in the following items.

[0008] [Item 1] An electric work vehicle comprising: a travel device; a PTO shaft for supplying power to a work machine; one or more electric motors for driving the travel device and the PTO shaft; a starter switch for starting the work vehicle; a specific mode switch provided at a distance from the starter switch for activating a specific function in the work vehicle; and a control device for controlling the operation of the work vehicle, wherein the control device, when the work vehicle is not started, starts the work vehicle in response to the operation of the starter switch and starts operation in a drive mode in which the travel device and the PTO shaft can be driven by the one or more electric motors; and when the work vehicle is not started, starts the work vehicle in response to the operation of the specific mode switch and starts operation in a specific mode in which the specific function is activated.

[0009] [Item 2] The work vehicle according to Item 1, further comprising: a battery for storing power supplied to one or more electric motors; and a charging inlet to which a charging adapter for charging the battery from an external power source is connected, wherein the specific mode is a charging mode that enables the function of charging the battery from the external power source via the charging inlet; the specific mode switch is a charging mode switch for starting the charging mode; and the control device, when the work vehicle is not started, starts the work vehicle in response to the operation of the charging mode switch and starts operation in the charging mode.

[0010] [Item 3] The work vehicle according to Item 2, further comprising a meter panel unit for displaying the status of the work vehicle, wherein the control device causes the meter panel unit to display the charge status of the battery in the charging mode.

[0011] [Item 4] The work vehicle described in Item 2, wherein the charging mode switch is located near the charging inlet.

[0012] [Item 5] The specific mode is a minute-movement mode that enables the function of moving the work vehicle forward or backward at a minute speed, the specific mode switch is a minute-movement mode switch for starting the minute-movement mode, and the control device, when the work vehicle is not started, starts the work vehicle in response to the operation of the minute-movement mode switch and starts operation in the minute-movement mode, as described in Item 1.

[0013] [Item 6] A work vehicle according to Item 5, wherein a minute forward switch and a minute reverse switch are provided near the minute movement mode switch, and the control device, in the minute movement mode, controls one or more electric motors to move the work vehicle forward at a minute speed in response to the operation of the minute forward switch, and controls one or more electric motors to move the work vehicle backward at a minute speed in response to the operation of the minute reverse switch.

[0014] [Item 7] The work vehicle described in Item 1, further comprising a three-point linkage supporting the work machine, wherein the specific mode is a height adjustment mode that enables the raising and lowering function of the three-point linkage, the specific mode switch is a height adjustment mode switch for starting the height adjustment mode, and the control device, when the work vehicle is not started, starts the work vehicle in response to the operation of the height adjustment mode switch and starts operation in the height adjustment mode.

[0015] [Item 8] The work vehicle according to Item 7, wherein an upward switch and a downward switch are provided near the height adjustment mode switch, and the control device, in the height adjustment mode, raises the three-point link in response to the operation of the upward switch, and lowers the three-point link in response to the operation of the downward switch.

[0016] [Item 9] The work vehicle according to Item 7, further comprising a hydraulic system for driving the three-point linkage, wherein the one or more electric motors include an electric motor for driving the hydraulic system.

[0017] [Item 10] The work vehicle according to Item 1, wherein the control device disables the operation of the one or more electric motors in the specific mode.

[0018] [Item 11] The work vehicle according to any one of items 1 to 10, wherein the one or more electric motors include a first electric motor that drives the travel device and a second electric motor that drives the PTO shaft.

[0019] [Item 12] A method performed by a computer controlling a work vehicle, wherein the work vehicle comprises a travel device, a PTO shaft for supplying power to a work machine, one or more electric motors for driving the travel device and the PTO shaft, a starter switch for starting the work vehicle, and a specific mode switch located away from the starter switch for activating a specific function in the work vehicle, the method comprising: starting the work vehicle in response to the operation of the starter switch when the work vehicle is not started, and starting operation in a drive mode in which the travel device and the PTO shaft can be driven by the one or more electric motors; and starting the work vehicle in response to the operation of the specific mode switch when the work vehicle is not started, and starting operation in a specific mode that activates the specific function.

[0020] [Item 13] A computer program executed by a computer that controls a work vehicle, wherein the work vehicle comprises a travel device, a PTO shaft that supplies power to a work machine, one or more electric motors that drive the travel device and the PTO shaft, a starter switch for starting the work vehicle, and a specific mode switch provided at a distance from the starter switch for enabling a specific function in the work vehicle, and the computer program causes the computer to: start the work vehicle in response to the operation of the starter switch when the work vehicle is not started, and start operation in a drive mode in which the travel device and the PTO shaft can be driven by the one or more electric motors; and start the work vehicle in response to the operation of the specific mode switch when the work vehicle is not started, and start operation in a specific mode in which the specific function is enabled.

[0021] [Item 13] A computer program executed by a computer that controls a work vehicle, wherein the work vehicle comprises a travel device, a PTO shaft that supplies power to a work machine, one or more electric motors that drive the travel device and the PTO shaft, a starter switch for starting the work vehicle, and a specific mode switch provided at a distance from the starter switch for enabling a specific function in the work vehicle, and the computer program causes the computer to: start the work vehicle in response to the operation of the starter switch when the work vehicle is not started, and start operation in a drive mode in which the travel device and the PTO shaft can be driven by the one or more electric motors; and start the work vehicle in response to the operation of the specific mode switch when the work vehicle is not started, and start operation in a specific mode in which the specific function is enabled.

[0022] [Item 14] A computer-readable non-temporary storage medium storing a computer program executed by a computer controlling a work vehicle, wherein the work vehicle comprises a running gear, a PTO shaft for supplying power to a work machine, one or more electric motors for driving the running gear and the PTO shaft, a starter switch for starting the work vehicle, and a specific mode switch located away from the starter switch for activating a specific function in the work vehicle, the storage medium causing the computer program to execute: when the work vehicle is not started, in response to the operation of the starter switch, start the work vehicle and begin operation in a drive mode that enables the driving gear and the PTO shaft to be driven by the one or more electric motors; and when the work vehicle is not started, in response to the operation of the specific mode switch, start the work vehicle and begin operation in a specific mode that enables the specific function.

[0023] Comprehensive or specific embodiments of the present invention may be realized by apparatus, systems, methods, integrated circuits, computer programs, or computer-readable non-temporary storage media, or any combination thereof. The computer-readable storage media may include volatile storage media or non-volatile storage media. The apparatus may consist of multiple devices. If the apparatus consists of two or more devices, these two or more devices may be located in a single device or in two or more separate devices.

[0024] According to embodiments of the present invention, it becomes possible to perform specific operations more easily, such as charging the battery of a work vehicle or making fine adjustments to the vehicle's position or the height of the three-point linkage for smooth attachment of a work machine to the work vehicle.

[0025] This is a schematic plan view showing an example of the basic configuration of a work vehicle according to an exemplary embodiment of the present invention. This is a side view of a work vehicle according to an exemplary embodiment of the present invention. This is a top view of a work vehicle. This is a block diagram showing an example of the main components of a work vehicle and their connection relationships. This is a block diagram showing an example of the configuration of a power converter and its connection to other equipment. This is a block diagram showing an example of the hardware configuration of each ECU. This is a block diagram showing an example of the configuration of a power distribution unit. This is a schematic front view showing a meter panel unit mounted on a work vehicle. This is a front view showing an example of the arrangement of the main components of the meter panel unit. This is a diagram for explaining the indicator area in the meter panel unit. This is a diagram for explaining an example of the display of a display element in the meter panel unit. This is a schematic diagram showing an example of the configuration of a charging inlet. This is a schematic diagram showing the situation in which a charging adapter is connected to the socket of the charging inlet. This is a flowchart showing an example of the operation of the control device when the work vehicle is started up. This is a diagram showing an example of the display when the vehicle is in a standby state in charging mode and charging has not started. This is a diagram showing an example of the display when charging is in progress in charging mode. This is a block diagram showing an example of a system configuration. This is a side view showing an example of a work vehicle that can operate in micro-movement mode or height adjustment mode. This is a diagram showing an example of an operation unit. This is a diagram showing another example of an operation unit. This figure shows yet another example of an operating unit. This flowchart shows an example of operation by a control device for a work vehicle that can operate in minute movement mode. This flowchart shows an example of operation by a control device for a work vehicle that can operate in height adjustment mode.

[0026] Embodiments of the present invention will be described below. However, unnecessarily detailed descriptions may be omitted. For example, detailed descriptions of already well-known matters and redundant descriptions of substantially identical configurations may be omitted. This is to avoid the following description becoming unnecessarily verbose and to facilitate understanding for those skilled in the art. The inventors provide the accompanying drawings and the following description so that those skilled in the art can fully understand the present invention, and not to limit the subject matter described in the claims. In the following description, components having the same or similar function are denoted by the same reference numerals.

[0027] The following embodiments are illustrative examples for realizing the technical concept of the present invention, and the present invention is not limited to these embodiments. For example, the numerical values, shapes, materials, steps, and order of steps shown in the following embodiments are merely examples, and various modifications are possible as long as they do not create a technical inconsistency. Furthermore, it is possible to combine one embodiment with other embodiments. The size and positional relationships of the components shown in each drawing may be exaggerated for ease of understanding.

[0028] (Definition of Terms) In this specification, “work vehicle” means a vehicle used for a specific task, such as agricultural work or construction work. “Work” may be, for example, agricultural work, construction work, rubble removal work, or snow removal work. Agricultural work vehicles may be, for example, tractors, combine harvesters, rice transplanters, riding cultivators, vegetable transplanters, vegetable harvesters, lawnmowers, seeders, or fertilizer spreaders. Construction work vehicles may be, for example, backhoes, wheel loaders, or carriers. An agricultural work vehicle such as a tractor or combine harvester, or a construction work vehicle, may function as a “work vehicle” on its own, or the work vehicle and any work equipment attached to or towed by it may function as a single “work vehicle.” Agricultural work vehicles perform agricultural work on the ground in a field, such as tilling, sowing, pest control, fertilizing, planting crops, or harvesting. Construction work vehicles perform work such as transporting soil, rubble, and other materials at a construction site. These tasks are sometimes referred to as "ground work" or simply "work." The act of a work vehicle moving while performing work is sometimes referred to as "work driving."

[0029] An "electric work vehicle" refers to a work vehicle that runs using an electric motor as its power source. An electric work vehicle may also be equipped with an internal combustion engine as an auxiliary power source in addition to the electric motor. Alternatively, an electric work vehicle may be equipped with an electric motor as an auxiliary power source in addition to the internal combustion engine. An electric work vehicle is equipped with an electrical energy source, such as a battery or fuel cell, to supply power to the electric motor. In the following description, an "electric work vehicle" may be simply referred to as a "work vehicle."

[0030] Electric motors can be synchronous motors such as permanent magnet synchronous motors or reluctance motors, or asynchronous motors such as induction motors.

[0031] A battery is an energy storage device that stores the electrical energy necessary for the operation of electric motors and other electrical components mounted on a work vehicle and / or work machine. A fuel cell is a power generation device that generates such electrical energy from a fuel such as hydrogen. An electrical energy source can be realized by an energy storage device, a power generation device, or a combination of an energy storage device and a power generation device. Furthermore, an electric work vehicle may obtain electrical energy from an electrical energy source located at a distance from the vehicle (e.g., on the ground or on another vehicle) via wired or wireless means.

[0032] When an electric work vehicle performs various "tasks" while moving or stationary, the power required for those tasks may be obtained from electric motors. An electric work vehicle is equipped with one or more electric motors. If an electric work vehicle is equipped with multiple electric motors, certain electric motors may output the driving force required for movement, while other electric motors may output the driving force required for the "tasks." If some or all of the "tasks" are performed by a work machine, the driving force can be mechanically transmitted from one or more electric motors on the electric work vehicle to the work machine. Such mechanical transmission of driving force can be achieved via a power transmission shaft called a power take-off (PTO) shaft.

[0033] The work machine itself may be equipped with an electric motor for the work. In this case, power may be supplied to the electric motor of the work machine from an electrical energy source such as a battery or fuel cell equipped in the electric work vehicle. The work machine may also be equipped with an electrical energy source that stores the power required for the work.

[0034] A "control device" (controller) is a device that controls the operation of part or all of a work vehicle. One example of a "control device" is a computing device comprising at least one processor and at least one memory that stores a computer program (code) that defines the control process executed by the processor. Another example of a "control device" is a computing device with a hardware accelerator such as an FPGA (Field-Programmable Gate Array), ASSP (Application Specific Standard Product), or ASIC (Application-Specific Integrated Circuit) configured or programmed to execute the control process. A control device may also be a collection of multiple devices. For example, several computing devices such as physically separated electronic control units (ECUs) may work together to function as a "control device".

[0035] A "processor" is a hardware electronic circuit such as a CPU (Central Processing Unit), GPU (Graphics Processing Unit), DSP (Digital Signal Processor), ISP (Image Signal Processor), or NPU (Neural Network Processing Unit).

[0036] "Memory" refers to hardware electronic circuits such as ROM (Read Only Memory) or RAM (Random Access Memory). Part of the memory may be a storage medium connected to the processor via wiring or a network. These hardware electronic circuits may be implemented by one or more integrated circuits (ICs) or large-scale integrated circuits (LSIs). Each functional unit or block and associated component within the electronic circuit may be manufactured individually as separate integrated circuit chips, or some or all of these functional units or blocks may be combined and manufactured as a single integrated circuit chip. Memory may store computer programs (hereinafter sometimes simply referred to as "programs") that define the operation of the processor. The programs are designed to cause the processor to perform one or more functions, operations, steps, or processes in embodiments of the present invention.

[0037] (Embodiments) Hereinafter, with reference to the drawings, several embodiments of the present invention applied to an electric agricultural tractor, which is an example of an electric work vehicle, will be described. The various technologies described for tractors in the following description can also be applied to agricultural machinery other than tractors, construction vehicles used at construction sites, work vehicles used at disaster sites, snowplows used in heavy snow areas, and vehicles for transporting goods, etc.

[0038] In the following explanation, the direction of arrow F in the diagram will be referred to as "forward," the direction of arrow B as "backward," the direction of arrow L as "left," the direction of arrow R as "right," the direction of arrow U as "up," and the direction of arrow D as "down."

[0039] <1. Basic Configuration of the Work Vehicle> Figure 1 is a schematic plan view showing an example of the basic configuration of a work vehicle 10 according to an exemplary embodiment of the present invention. The work vehicle 10 shown is an electric tractor for agricultural use. The work vehicle 10 can travel within a field while carrying or towing implements and performing agricultural work according to the type of implement. The work vehicle 10 can also travel within and outside of a field (including roads) with the implement lifted or without the implement attached.

[0040] The work vehicle 10 is equipped with a body (vehicle frame) 11 that rotatably supports the left and right front wheels 14F and the left and right rear wheels 14R. The body 11 includes a front frame 12 on which the front wheels 14F are mounted and a transmission case 13 on which the rear wheels 14R are mounted. The front frame 12 is fixed to the front of the transmission case 13. The front wheels 14F and the rear wheels 14R may be collectively referred to as "wheels 14". Strictly speaking, wheels 14 are wheels, and tires are mounted on the wheels 14. In this disclosure, "wheels" generally means the entire "wheel and tire". One or both of the front wheels 14F and the rear wheels 14R may be replaced with a plurality of wheels (crawlers) equipped with a track instead of wheels with tires.

[0041] The work vehicle 10 in the example shown in Figure 1 is equipped with a battery 20 and an electric motor 30 (hereinafter simply referred to as "motor 30") which are directly or indirectly supported by the front frame 12. The battery 20 may be configured as a battery pack including, for example, multiple cells connected in series. The battery 20 is a rechargeable battery that outputs a relatively high voltage, such as a lithium-ion battery or an all-solid-state battery. The battery 20 stores power to drive the motor 30. The battery 20 may be housed in a front housing, for example, called a "bonnet." The front housing is supported by the front frame 12 located at the front of the vehicle body 11.

[0042] Motor 30 is electrically connected to battery 20. Motor 30 can convert the electric power output from battery 20 into mechanical motion (power) to generate the driving force (traction) required for the operation of work vehicle 10. Motor 30 can be, for example, an AC synchronous motor. Battery 20 generates direct current. Therefore, when motor 30 is an AC synchronous motor, an electric circuit group including an inverter device (hereinafter sometimes simply referred to as "inverter") may be provided between battery 20 and motor 30. The inverter device converts direct current into alternating current. A part of such an electric circuit group may be inside battery 20. Also, another part of the electric circuit group may be attached to motor 30 as a drive circuit of motor 30.

[0043] Motor 30 has a rotating output shaft 33. The torque of output shaft 33 is transmitted to rear wheel 14R through mechanical components such as a transmission (speed change device) provided inside transmission case 13 and a rear wheel differential device (differential gear device). In other words, the power generated by motor 30, which is a power source, is transmitted to rear wheel 14R by a power transmission system (drive train) 34 including a transmission provided inside transmission case 13. For this reason, the "transmission case" may be called the "mission case". In the four-wheel drive mode, a part of the power of motor 30 is also transmitted to front wheel 14F. Thus, motor 30 drives a traveling device including a plurality of wheels 14.

[0044] The power of motor 30 may be used not only for the operation of work vehicle 10 but also for driving the work implement. A PTO shaft 40 is provided at the rear end of transmission case 13. A work implement can be connected to PTO shaft 40. PTO shaft 40 can be driven by motor 30 that drives the traveling device or another electric motor not shown in FIG. 1. The torque of output shaft 33 of motor 30 or the output shaft of another motor is transmitted to PTO shaft 40. The work implement mounted on or towed by work vehicle 10 can receive power from PTO shaft 40 and perform operations according to various operations. Motor 30 and power transmission system 34 may be collectively referred to as an electric powertrain.

[0045] As shown in Figure 1, the work vehicle 10 does not have an internal combustion engine such as a diesel engine, but is equipped with a battery 20 and a motor 30. The output shaft 33 of the motor 30 is mechanically coupled to a power transmission system 34, such as a transmission, in a transmission case 13. The motor 30 can efficiently generate torque over a relatively wide range of rotational speeds compared to an internal combustion engine. By using the power transmission system 34, including the transmission, it becomes easy to adjust the torque and rotational speed from the motor 30 over an even wider range by performing multi-stage or continuously variable speed changes. Therefore, it is possible to efficiently perform not only the movement of the work vehicle 10 but also a variety of tasks using work equipment.

[0046] Depending on the intended use or size of the work vehicle 10, some functions of the power transmission system 34 may be omitted. For example, some or all of the transmission responsible for the gear shifting function may be omitted. The number and mounting positions of the motors 30 are not limited to the example shown in Figure 1. Furthermore, the work vehicle may be a hybrid electric vehicle (HEV) equipped with an internal combustion engine such as a diesel engine as a power source in addition to electric motors.

[0047] The work vehicle 10 shown in FIG. 1 includes one motor 30. However, the work vehicle 10 may include a plurality of electric motors. For example, the work vehicle 10 may include a traveling electric motor that drives a traveling device including four wheels 14, and a PTO electric motor that drives a PTO shaft 40. The work vehicle 10 may include a plurality of PTO shafts (for example, a rear PTO shaft, a mid PTO shaft, a front PTO shaft, etc.). In that case, one electric motor may drive a plurality of PTO shafts, or a plurality of electric motors may drive a plurality of PTO shafts. For example, the work vehicle 10 may include a plurality of electric motors each driving a corresponding one of the plurality of PTO shafts. The work vehicle 10 may include a front-wheel electric motor that drives two front wheels 14F, and a rear-wheel electric motor that drives two rear wheels 14R. Alternatively, the work vehicle 10 may include two front-wheel electric motors that respectively drive two front wheels 14F, and two rear-wheel electric motors that respectively drive two rear wheels 14R. That is, the work vehicle 10 may include four electric motors that respectively drive four wheels 14. Thus, the work vehicle 10 may include one or more traveling electric motors that drive the traveling device, and one or more PTO electric motors that drive one or more PTO shafts. By including a plurality of electric motors, the work vehicle 10 can more flexibly control the rotation of the plurality of wheels 14 and one or more PTO shafts. In the following description, the traveling electric motor may be referred to as a "traveling motor", and the PTO electric motor may be referred to as a "PTO motor".

[0048] <2. Specific Example of Work Vehicle> Next, an example of a more specific configuration of the work vehicle 10 will be described.

[0049] FIG. 2 is a side view of the work vehicle 10 according to an exemplary embodiment of the present invention. FIG. 3 is a top view of the work vehicle 10 according to the present embodiment.

[0050] The work vehicle 10 shown in FIGS. 2 and 3 includes a vehicle body 11 and a traveling device supported by the vehicle body 11. The traveling device includes various devices necessary for traveling, such as left and right front wheels 14F, left and right rear wheels 14R, a front axle 15F, a rear axle 15R, and a rear-wheel differential device.

[0051] The vehicle body 11 comprises a front frame 12, a transmission case 13, and a housing frame 16. The front frame 12 is connected to the front of the housing frame 16. The transmission case 13 is connected to the rear of the housing frame 16. A first electric motor 30A and a second electric motor 30B are housed inside the housing frame 16. The first electric motor 30A is a driving motor and drives the running gear via a power transmission system in the transmission case 13. The second electric motor 30B is a PTO motor and drives the PTO shaft 40 and one or more hydraulic pumps. The first electric motor 30A and the second electric motor 30B may be electric motors capable of relatively high efficiency and high torque output, such as permanent magnet synchronous motors.

[0052] The front frame 12 is fitted with a front axle case 17F. The front axle case 17F supports the left and right front wheels 14F. The transmission case 13 includes a rear axle case 17R. The rear axle case 17R supports the left and right rear wheels 14R and transmits power to the rear wheels 14R.

[0053] A battery 20 is mounted on the front frame 12. The battery 20 is supported by the front frame 12 and housed inside the front housing 19 (bonnet). The battery 20 stores the power supplied to the first electric motor 30A and the second electric motor 30B. In other words, the battery 20 stores power for driving, operation, and hydraulic drive. In the following description, the battery 20 may be referred to as the "drive battery 20".

[0054] Above the housing frame 16 and the transmission case 13 are a steering wheel 53, a meter panel unit 54, a group of pedals 55 including the accelerator and brake, a group of switches 56 for work driving, and a driver's seat 52. A safety frame 51 is provided behind the driver's seat 52. The safety frame 51 is attached to the transmission case 13 and has a structure that extends upward. Inside the housing frame 16 are the first electric motor 30A and the second electric motor 30B.

[0055] The switch group 56 includes various operating devices such as switches, levers, and dials for adjusting the operation of the work vehicle 10 and the work implement. The switch group 56 includes various operating devices such as an accelerator lever for adjusting the travel speed, a switch for switching the PTO shaft 40 on and off, a dial for adjusting the rotational speed of the PTO shaft 40, and a lever for adjusting the height of the three-point linkage supporting the work implement. By operating the switch group 56, the driver can give various instructions to the work vehicle 10 for travel and work.

[0056] The meter panel unit 54 displays information regarding the status of the work vehicle 10. For example, the meter panel unit 54 displays various information such as the travel speed, the rotational speed of the PTO shaft 40, the height of the three-point linkage, the output of the motors 30A and 30B, the charge status of the battery 20, and the temperature of the battery 20. The meter panel unit 54 may be equipped with analog meters and / or a digital display (hereinafter sometimes simply referred to as "display") for displaying this information. The display of the meter panel unit 54 may display a graphical user interface (GUI) that allows the user to perform various setting operations related to the work vehicle 10. The user can perform various settings related to the work vehicle 10 on the display screen using an input device connected to the meter panel unit 54 or an input means such as a touchscreen mounted on the display.

[0057] As shown in Figure 3, a charging inlet 57 is provided to the right of the steering wheel 53. The charging inlet 57 is a device that includes a socket configured to allow connection of a charging adapter extending from an external power source or charging device. Near the charging inlet 57, a device for the user to initiate charging, such as a charging start button, may be provided. When the user connects the charging adapter to the charging inlet 57 and performs a predetermined operation, such as pressing the charging start button, charging of the battery 20 begins.

[0058] The battery 20 can be charged using either normal charging or rapid charging. In normal charging, AC power supplied from an external AC power source is converted to high-voltage DC power (e.g., around 350V to 450V), and this DC power is supplied to the battery 20. In rapid charging, high-voltage DC power is directly supplied to the battery 20 from an external DC power source. The charging inlet 57 in this embodiment supports both normal and rapid charging. For normal charging, a commercial AC power source that outputs an AC voltage of, for example, 200V or 100V may be used as the power source. For rapid charging, a DC power source that outputs a DC voltage of, for example, around 350V to 450V may be used as the power source. Rapid charging can be performed using protocols compliant with standards such as CHAdeMO, NACS, CCS1, CCS2, GB / T, or ChaoJi.

[0059] The power stored in the battery 20 can also be output to external electrical equipment via the charging inlet 57. Such external power output is referred to as "external power supply" in this specification. External power supply is performed with an external power supply adapter connected to the charging inlet 57. The DC power from the battery 20 can be converted to AC power by a power converter in the work vehicle 10. This AC power can then be supplied to external equipment via the charging inlet 57 and the external power supply adapter.

[0060] As shown in Figure 3, the first electric motor 30A and the second electric motor 30B in this embodiment are arranged side by side. The first electric motor 30A and the second electric motor 30B are rotated by power supplied from the battery 20. The first electric motor 30A drives the running gear via a power transmission system in the transmission case 13. The second electric motor 30B drives the PTO shaft 40 and the hydraulic pump via a power transmission system in the transmission case 13. As a result, the second electric motor 30B drives the work implement and various hydraulic devices. The hydraulic devices may be used, for example, to change the height of the three-point linkage supporting the work implement. The work vehicle 10 may be equipped with a power steering system that assists the driver's steering wheel operation. In this case, the hydraulic devices may also be used in the power steering system to supply auxiliary force to change the steering angle of the front wheels 104F.

[0061] <3. System Configuration of the Work Vehicle> Figure 4 is a block diagram showing the main components of the work vehicle 10 and an example of their connection relationships. In Figure 4, connection relationships related to power transmission, high-voltage drive power, and low-voltage auxiliary power are represented by solid lines of different thicknesses. Connection relationships related to signals (digital signals and analog signals) are represented by dotted lines. Coolant flow is represented by thick dashed lines.

[0062] As shown in Figure 4, the work vehicle 10 is equipped with a first inverter 35A and a second inverter 35B. The first inverter 35A is connected to the first electric motor 30A. The second inverter 35B is connected to the second electric motor 30B. Each of the first inverter 35A and the second inverter 35B converts the DC voltage from the battery 20 into a three-phase AC voltage. The first inverter 35A supplies the converted three-phase AC voltage to the first electric motor 30A. This causes the first electric motor 30A to rotate and the traction device to be driven. The second inverter 35B also supplies the converted three-phase AC voltage to the second electric motor 30B. This causes the second electric motor 30B to rotate and the hydraulic pump 36 and the PTO shaft 40 to be driven.

[0063] The transmission case 13 houses the power transmission system 34A for driving, the power transmission system 34B for work, and the hydraulic pump 36. The power transmission system 34A for driving may include components such as a reduction gear, a sub-transmission, and a differential. The power transmission system 34A for driving transmits power from the rotation of the first electric motor 30A to the rear wheels 14R. In four-wheel drive mode, the power transmission system 34A for driving also transmits a portion of the power from the rotation of the first electric motor 30A to the front wheels 14F. The power transmission system 34B for work may include components such as a reduction gear, a PTO clutch, and a PTO transmission. The power transmission system 34B for work transmits power from the rotation of the second electric motor 30B to the hydraulic pump 36 and the PTO shaft 40. The PTO shaft 40 supplies power for work to the work implement.

[0064] The PTO shaft 40 shown in Figure 4 is the rear PTO shaft. In addition to the rear PTO shaft, the work vehicle 10 may also have a mid-PTO shaft or a front PTO shaft. If the work vehicle 10 has multiple PTO shafts, the power transmission system 34B may be configured to distribute the power generated by the rotation of the second electric motor 30B to the multiple PTO shafts. Alternatively, in addition to the second electric motor 30B that drives the PTO shaft 40, the work vehicle 10 may include other electric motors that drive the other PTO shafts.

[0065] The implements connected to the PTO shaft 40 may include, for example, a rotary tiller, a seeder, a spreader, a transplanter, a mower, a rake, a baler, a harvester, a sprayer, or a harrow. Any implement can be connected to the work vehicle 10 and used.

[0066] The hydraulic pump 36 is driven by power from the second electric motor 30B. The hydraulic pump 36 pressurizes the hydraulic fluid, thereby changing the height of the three-point linkage to which the work equipment is connected. Alternatively, the hydraulic pump 36 may be used in a hydraulic power steering system. If a front loader is mounted as the work equipment, the hydraulic pump 36 may be used in a hydraulic system that enables the lifting and lowering of the front loader. Power from the second electric motor 30B may be transmitted to multiple hydraulic pumps to drive these multiple hydraulic systems. Alternatively, the work vehicle 10 may have one or more electric motors for hydraulics separate from the second electric motor 30B.

[0067] In the example shown in Figure 4, the work vehicle 10 further comprises a power converter 58, a power distribution unit (PDU) 80, an auxiliary battery 21, and a battery temperature control system 70.

[0068] The power converter 58 is positioned between the charging inlet 57 and the battery 20 and performs power conversions such as AC to DC conversion and voltage conversion. Figure 5 shows an example of the configuration of the power converter 58 and its connection to other equipment. The power converter 58 shown in Figure 5 includes an onboard charger (OBC) 81 and a DC-DC converter 82. During normal charging, the OBC 81 converts AC power from the charging inlet 57 to DC power and supplies it to the drive battery 20 via the power distribution unit 80. The drive battery 20 is charged by this DC power. The DC-DC converter 82 is connected to the OBC 81 and also to the battery 20 via the power distribution unit 80. The DC-DC converter 82 converts the relatively high-voltage DC power output from the OBC 81 or the drive battery 20 to lower-voltage DC power (e.g., 12V or 24V). The low-voltage DC power converted by the DC-DC converter 82 is supplied to the auxiliary battery 21 and the auxiliary components 84. The auxiliary components 84 include several devices that operate on the relatively low voltage output from the DC-DC converter 82 or the battery 21. For example, the auxiliary components 84 include several electronic control units (ECUs) and other electrical components. The auxiliary battery 21 is charged by the DC voltage output from the DC-DC converter 82. The auxiliary battery 21 stores the power supplied to the auxiliary components 84, such as each ECU, the meter panel unit 54, the pumps 67, 77, and the air conditioner. The battery 21 may be, for example, a lead-acid battery.

[0069] Refer to Figure 4 again. The work vehicle 10 is equipped with multiple ECUs. The multiple ECUs include a main ECU 61, an electric ECU 62, and a charging ECU 63. The main ECU 61 controls the overall operation of the work vehicle 10 based on signals generated by the user operating the pedal group 55, the switch group 56, and the meter panel unit 54. The electric ECU 62 mainly controls the charging and discharging of the battery 20 and the operation of the electric motors 30A and 30B. The charging ECU 63 communicates with an external charger (external power supply) and performs control to ensure smooth charging by appropriately controlling the relay 64.

[0070] In this embodiment, the combination of the main ECU 61, the electric ECU 62, and the charging ECU 63 functions as a "control device" that controls the operation of the work vehicle 10. Therefore, in the following description, the operations performed by the main ECU 61, the electric ECU 62, and the charging ECU 63 all correspond to operations performed by the "control device". These ECUs can communicate with each other according to a vehicle bus standard such as CAN (Controller Area Network). Instead of CAN, a faster communication method such as on-board Ethernet (registered trademark) may be used. An on-board computer integrating at least some of the functions of the main ECU 61, the electric ECU 62, and the charging ECU 63 may be provided as the "control device". The control device may include ECUs other than the main ECU 61, the electric ECU 62, and the charging ECU 63. Each ECU may be a computing device including one or more processors and one or more memories. Each ECU can perform the operations described later by having the processor execute a computer program stored in the memory.

[0071] The electric ECU 62 sends control signals to the first inverter 35A and the second inverter 35B in response to signals from the pedal group 55 and the switch group 56. The electric ECU 62 can perform motor control based on a rotational speed command value or a torque command value determined, for example, according to the amount of operation of the pedal group 55 by the driver.

[0072] The electric ECU 62 controls the switching operation of multiple switch elements (e.g., MOSFETs) in the first inverter 35A and the second inverter 35B, respectively. Specifically, the electric ECU 62 generates control signals to control the switching operation of each switch element and outputs them to each inverter. The first inverter 35A converts the DC power from the battery 20 into three-phase AC power, which is a pseudo-sine wave of, for example, u-phase, v-phase, and w-phase, according to the control signals from the electric ECU 62, and supplies this three-phase AC power to the first electric motor 30A. Similarly, the second inverter 35B converts the DC power from the battery 20 into three-phase AC power, which is a pseudo-sine wave of, for example, u-phase, v-phase, and w-phase, according to the control signals from the electric ECU 62, and supplies this three-phase AC power to the second electric motor 30B. As a result, the electric ECU 62 can rotate the electric motors 30A and 30B at appropriate rotational speeds and torques according to the driver's operation.

[0073] While the work vehicle 10 is in operation, the main ECU 61 causes the meter panel unit 54 to display information regarding the status of the work vehicle 10. For example, the main ECU 61 displays information such as the travel speed, the operating status of the motors 30A and 30B, the charge status of the battery 20, and the status of the power transmission system 34A and the transmission included in 34A on the meter panel unit 54.

[0074] Figure 6 is a block diagram showing an example of the hardware configuration of each ECU. Each ECU includes a processor 434, ROM 435, RAM 436, external I / F 437, and communication I / F 438. These components are interconnected via a bus 439.

[0075] ROM 435 is, for example, writable memory (e.g., PROM), rewritable memory (e.g., flash memory), or read-only memory. ROM 435 stores a program that controls the operation of the processor 434. ROM 435 does not have to be a single recording medium; it may be a collection of multiple recording media. Some of the multiple storage media may be removable memory.

[0076] RAM 436 provides a working area for temporarily unpacking the program stored in ROM 435 at boot time. RAM 436 does not need to be a single recording medium; it may be a collection of multiple recording media.

[0077] External I / F 437 is an interface for connecting to external devices. Communication I / F 438 is an interface for communicating with other electronic devices (e.g., sensors and other ECUs). For example, communication I / F 438 can perform wired communication compliant with various protocols such as CAN or Ethernet®. Communication I / F 438 may also perform wireless communication compliant with wireless communication standards such as Bluetooth® and / or Wi-Fi®.

[0078] The ECU may further include a storage device for storing data generated by the processor 434 for a relatively long period of time. Such a storage device may be, for example, a semiconductor storage device, a magnetic storage device, or an optical storage device, or a combination thereof.

[0079] The power distribution unit 80 shown in Figure 4 is a device that electrically connects equipment such as the charging inlet 57, power converter 58, battery 20, inverters 35A and 35B, and heater 72.

[0080] Figure 7 shows an example of the configuration of the power distribution unit 80. The power distribution unit 80 may have a plurality of relay circuits 83 (83a to 83g) that operate under the control of the electric ECU 62. During charging, the power distribution unit 80 is configured to supply power from the charging inlet 57 or the power converter 58 to the battery 20, and to the heater 72 when the temperature is low. On the other hand, during discharging, the power distribution unit 80 is configured to distribute power from the battery 20 to the first inverter 35A, the second inverter 35B, and the power converter 23. The electric ECU 62 may be configured or programmed to control the charging and discharging of the battery 20 by appropriately switching the on and off of the plurality of relay circuits 83a to 83g in the power distribution unit 80. In this specification, relay circuits may be simply referred to as "relays".

[0081] As shown in Figure 4, the battery 20 includes a battery management system (BMS) 22 and a temperature sensor 24. The BMS 22 is configured to monitor the state of the battery 20, such as the input voltage, output voltage, and temperature, and to control the charging and discharging currents to the battery 20 based on these states. The temperature sensor 24 may be configured to measure the temperature of each of the multiple cells contained in the battery 20.

[0082] The work vehicle 10 illustrated in Figure 4 is equipped with a cooling system 60 for high-voltage equipment and a battery temperature control system 70. The cooling system 60 is used to cool equipment to which high voltage is applied (also referred to as "high-voltage equipment"). The cooling system 60 comprises a radiator 65, a reservoir tank 66, a pump 67, and a cooling fan 68. In the example in Figure 4, the cooling system 60 is connected via hoses to the first inverter 35A, the first electric motor 30A, the second electric motor 30B, the second inverter 35B, and the power converter 58 in that order. This forms a flow path through which the coolant circulates. The coolant in the cooling system 60 is, for example, water or oil. The cooling system 60 cools these high-voltage equipment by circulating the coolant through the flow path. The coolant heated by the high-voltage equipment is cooled by heat dissipation in the radiator 65. The cooling fan 68 generates cooling air to cool the coolant inside the radiator 65. The cooling air promotes heat dissipation from the radiator 65.

[0083] The battery temperature control system 70 is used to cool or heat (also referred to as "heating") the battery 20. The battery temperature control system 70 comprises a heater 72, a radiator 75, a reservoir tank 76, and a pump 77. The battery temperature control system 70 is connected to the battery 20 via a hose. This creates a passage through which the coolant circulates. The coolant in the battery temperature control system 70 is, for example, water or oil. The battery temperature control system 70 cools the battery 20 by circulating the coolant through the passage. The coolant heated by the battery 20 is cooled by heat dissipation in the radiator 75. Cooling air from the cooling fan 68 also plays a role in cooling the coolant inside the radiator 75. The heater 72 raises the temperature of the battery 20 by warming the coolant. This makes it possible to suppress a decrease in the charge and discharge performance of the battery 20 even in low-temperature environments where the ambient temperature is, for example, below 0 degrees Celsius (°C).

[0084] The operation of the cooling system 60 and the battery temperature control system 70 is controlled by the electric ECU 62. For example, the electric ECU 62 is configured or programmed to maintain the temperature of the battery 20 within an appropriate range by controlling the battery temperature control system 70 based on the temperature of the battery 20 measured by the temperature sensor 24. In addition to the measurement value of the temperature sensor 24, the electric ECU 62 may also control the battery temperature control system 70 based on the measurement value of a temperature sensor 25 that measures the ambient temperature and is installed in the work vehicle 10.

[0085] The flow paths of the coolant in the cooling system 60 and the battery temperature control system 70 are not limited to the illustrated paths and can be changed as appropriate. The cooling method in the cooling system 60 and the battery temperature control system 70 is not limited to water cooling or oil cooling, but may also be air cooling. Alternatively, the refrigerant used in an air conditioner may be used instead of the above-mentioned coolant.

[0086] <4. Example of Meter Panel Unit Configuration> Figure 8 is a schematic front view showing a meter panel unit 54 attached to a work vehicle 10. In the illustrated example, the meter panel unit 54 is positioned on the front side of the driver's seat of the work vehicle 10. Specifically, the meter panel unit 54 is fitted into an opening in the meter cover 240 above the handle stay 230 that rotatably supports the steering wheel 220 (handle). The meter panel unit 54 is positioned so that it can be seen by the driver seated in the driver's seat.

[0087] Figure 9 is a front view showing an example of the arrangement of the main components of a meter panel unit 54. The meter panel unit 54 shown in Figure 9 includes a meter section 110. The meter section 110 has a first analog meter 111, a second analog meter 112, and a display element 113. The display element 113 is positioned between the first analog meter 111 and the second analog meter 112.

[0088] The first analog meter 111 has an indicator needle 102A. The second analog meter 112 has indicator needles 102B and 102C. Indicator needle 102A is rotatably supported around a pivot axis located near the center of the first analog meter 111. Depending on the direction in which the tip of indicator needle 102A points, it indicates, for example, the total power consumption or total output of the first electric motor 30A and the second electric motor 30B. Indicator needles 102B and 102C are rotatably supported around two pivot axes located at different locations on the second analog meter 112. Depending on the direction in which the tip of indicator needle 102B points, it indicates, for example, the battery level. Indicator needle 102C indicates, for example, the battery temperature, depending on the direction in which the tip of indicator needle 102C points. The indicator needles 102A, 102B, and 102C are driven by the drive unit (movement) provided in the meter unit 110. The drive unit receives electrical signals indicating sensor outputs such as the power consumption of the first electric motor 30A and the second electric motor 30B, the battery level, or the battery temperature, and can convert these into mechanical motion that changes the direction of the indicator needles 102A, 102B, and 102C. Each of the drive units for the indicator needles 102A, 102B, and 102C has an actuator such as a stepping motor.

[0089] The first analog meter 111 further comprises a first arc-shaped indicator 140A. The second analog meter 112 further comprises a second arc-shaped indicator 140B. The first arc-shaped indicator 140A is positioned around the movable area of ​​the indicator needle 102A. The second arc-shaped indicator 140B is positioned around the movable areas of the indicator needles 102B and 102C. In this disclosure, "arc" means a part of a circle (circumference), but this circle is not limited to a "perfect circle" and may include a part where the curvature changes gradually or locally, such as a part of an ellipse. The first arc-shaped indicator 140A and the second arc-shaped indicator 140B have a symmetrical structure.

[0090] Each of the arc-shaped indicators 140A and 140B may include multiple light-emitting elements (e.g., LEDs) that emit light of different colors. These multiple light-emitting elements may include, for example, LEDs that emit red light, LEDs that emit green light, and LEDs that emit blue light. By selectively emitting these LEDs, the arc-shaped indicators 140A and 140B can perform the function of notifying the operator of information using light of various colors. For this reason, the arc-shaped indicators 140A and 140B are sometimes referred to as "communication rings."

[0091] The display element 113 is a digital meter (i.e., a digital display), not an analog meter. The display element 113 is, for example, an active-matrix display such as a liquid crystal display panel or an OLED (Organic Light Emitting Diode). The display element 113 has a large number of pixels arranged two-dimensionally in a display area, and a display visible to the human eye is realized by the light emitted from the large number of pixels. In the display element 113 in this embodiment, each pixel includes RGB subpixels, and a color image can be displayed. The display element 113 can display numbers, characters, figures, icons, symbols, still images, or moving images of any size at any position within the display area. Strictly speaking, numbers, characters, figures, icons, and symbols are also part of the image (still image or moving image) that the display element 113 displays in the display area. The display element 113 can also display an image that, for example, superficially resembles all or part of an analog meter with an indicator needle. When the display element 113 displays an image of an "analog meter," it is possible to rotate the "indicator needle" in the image to any direction as part of a video by changing the image frame by frame.

[0092] The difference between the image of the "analog meter" displayed by a digital display such as the display element 113 and the first analog meter 111 and the second analog meter 112 is that the former is two-dimensional, while the latter is three-dimensional. Furthermore, the former allows for changes in the shape, color, and size of the indicator needle and scale of the analog meter, whereas it is difficult to change these in the latter. In addition, the visibility of the former depends on the contrast of the image, so visibility may decrease when exposed to strong sunlight during the day, whereas this possibility is relatively small in the latter. Taking these factors into consideration, in this embodiment, some of the information displayed on the meter unit 110, especially information of high importance that requires strong visibility, is displayed by an analog meter with a three-dimensional structure.

[0093] When viewed from the front, the meter section 110 has an outline that resembles an ellipse, but the outline of the meter section 110 is not limited to this example. When viewed from the front, the outline of the meter section 110 may be roughly a rectangle, or it may be a figure that combines straight lines and curves.

[0094] Next, the indicator area of ​​the meter unit 110 will be described with reference to Figure 10. In the example of Figure 10, the meter unit 110 has an indicator area 114T provided above the display element 113, and indicator areas 114L and 114R provided below the display element 113. Various indicators are provided in each of the indicator areas 114T, 114L, and 114R. When the light-emitting element behind each indicator, such as an LED, is lit, it displays predetermined information such as a warning.

[0095] In this embodiment, two indicator areas 114L and 114R, which are divided into left and right sections, are arranged at the bottom of the display element 113. However, a single indicator area formed by integrating the two indicator areas may also be arranged.

[0096] In the indicator area 114T located above the display element 113, indicators that show particularly important information (information with a high warning level) may be selected and placed from among a number of indicators (for example, indicators that show the illumination status of lighting devices, turn signals, warnings to the driver, etc.). The "warning level" of the information displayed by the indicators may be defined, for example, in the owner's manual for the work vehicle. For example, information such as motor abnormality or failure, or whether the headlights are illuminated, has a high warning level.

[0097] In this embodiment, each indicator located in the indicator areas 114T, 114L, and 114R consists of a translucent area shaped to define a characteristic figure (including icons and / or characters) and a light-emitting element located behind it. The indicators can be turned on or off by turning the light-emitting element behind them on or off. Behind each indicator, for example, one or two light-emitting elements are located.

[0098] Next, an example of the display of the display element 113 will be described with reference to Figure 11. In the example in Figure 11, the display area of ​​the display element 113 is divided into several areas. Each area displays an "image" showing information such as the gear shift stage, vehicle speed, various function performance displays, and hour meter. This image contains various types of information represented by letters, numbers, shapes, icons, symbols, etc. Diverse digital images may be shown in different colors to enhance visibility. Furthermore, when it is particularly important to attract the operator's attention, the position, size, or color of at least one of the letters, numbers, shapes, icons, or symbols may be changed to provide a highlighted display. When such a highlighted display is performed, sound or voice may be emitted from an audio device such as a speaker.

[0099] <5. Starting the work vehicle using a specific mode switch> The work vehicle 10 shown in Figure 3 is equipped with a starter switch 59. The starter switch 59 is a switch used to start the work vehicle 10, and may be, for example, a push-button switch. The starter switch 59 is also called an "ignition switch" or "power switch". The starter switch 59 is used to start the work vehicle 10 in a drive mode in which the running gear and PTO shaft can be driven, or in an accessory mode in which various electrical components are operated without driving the running gear and PTO shaft. In the example in Figure 3, the starter switch 59 is located to the lower right of the steering wheel 53. The starter switch 59 may be located in other positions. The operation in which the user turns on the starter switch 59 using the starter key of the work vehicle 10 is called a "key-on operation". The starter key may be, for example, an electronic key capable of transmitting and receiving radio waves. A key-on operation may be, for example, an operation in which the user presses the starter switch 59 of the work vehicle 10 while the starter key is nearby. When the key is turned on, the system inside the work vehicle 10 starts up.

[0100] The work vehicle 10 can operate in accessory mode and drive mode. Accessory mode is a mode in which the electric motors 30A and 30B are stopped and various electrical components in the work vehicle 10 are operated. Drive mode is a mode in which the electric motors 30A and 30B are driven to enable driving and work. For example, if the user does not press the accelerator pedal and the PTO switch is off when the key is turned on, the work vehicle 10 may be configured to start in drive mode. On the other hand, if the user presses the accelerator pedal or the PTO switch is on when the key is turned on, the work vehicle 10 may be configured to start in accessory mode. The accelerator pedal is a pedal for controlling the rotational speed and direction of the first electric motor 30A for driving. The PTO switch is a switch for switching the PTO shaft 40 on and off. The user can also switch between accessory mode and drive mode by operating the starter switch 59.

[0101] In this embodiment, the work vehicle 10 is further equipped with a specific mode switch, separate from the starter switch 59, for restricting driving and work operations and enabling other specific functions. The specific mode switch is a switch for starting the work vehicle 10 in a specific mode that restricts the driving of the travel device and the PTO shaft and enables only specific functions such as charging. The specific mode includes, for example, at least one of the following modes: ・Charging mode: A mode that enables the function of charging the battery 20 from an external power source via the charging inlet 57. ・Micro-movement mode: A mode that enables the function of moving the work vehicle 10 forward or backward at a small speed. ・Height adjustment mode: A mode that enables the function of raising and lowering the three-point linkage to adjust the position of the work implement. The specific mode may also include modes other than these three modes. These modes are activated by their respective unique switches. Note that the accessory mode is activated by the starter switch, similar to the drive mode, and therefore does not fall under the category of "specific mode". In the specific mode, the operation of one or more electric motors (either or both of the electric motor 30A for driving and the electric motor 30B for driving the PTO) is disabled or restricted.

[0102] In the following description, the specific mode switches used to start the work vehicle 10 in charging mode, minute movement mode, or height adjustment mode will be referred to as the "charging mode switch," "minute movement mode switch," and "height adjustment mode switch," respectively.

[0103] In the work vehicle 10, the specific mode switch is located in a different position from the starter switch 59. For example, the charging mode switch may be located near the charging inlet 57. The minute movement mode switch and the height adjustment mode switch may be located, for example, on the side of the vehicle body 11 or near the three-point linkage.

[0104] The control device (e.g., main ECU 61) of the work vehicle 10 is configured to start the work vehicle 10 in response to the user's operation of the starter switch 59 when the work vehicle 10 is not running, and to start operation in a drive mode that enables the driving of the travel device and PTO shaft 40. On the other hand, when the work vehicle 10 is not running, the control device is configured to start the work vehicle 10 in response to the user's operation of a specific mode switch, and to start operation in a specific mode that enables a specific function.

[0105] The following describes an example of a specific mode switch, specifically a configuration in which the work vehicle 10 is equipped with a charging mode switch.

[0106] Figure 12 is a schematic diagram showing an example configuration of a charging inlet 57. The charging inlet 57 shown in Figure 12 includes a socket 571 for connecting a charging adapter and a charging mode switch 573. In this example, the charging mode switch 573 is a push-button switch. The charging mode switch 573 may be of other types. In the example shown in Figure 12, the socket 571 has a structure based on the CCS1 standard. The structure of the socket 571 varies depending on the charging standard used. Depending on the charging standard used, two sockets, one for normal charging and one for fast charging, may be provided in the charging inlet 57.

[0107] The charging mode switch 573 is used to start the work vehicle 10 in charging mode, which enables charging functions when the work vehicle 10 is stopped and not running. In charging mode, functions related to driving and work are disabled. In charging mode, in addition to charging, the function of supplying power to an external source may be enabled. When the user presses the charging mode switch 573 while the power to the work vehicle 10 is not turned on, the control device starts the work vehicle 10 and starts operation in charging mode. In charging mode, charging becomes possible when the charging adapter is connected to the socket 571 of the charging inlet 57.

[0108] Figure 13 schematically shows the state in which the charging adapter 90 is connected to the socket 571 of the charging inlet 57. As shown in Figure 13, with the charging adapter 90 connected to the socket 571, the battery 20 is charged by supplying electrical energy from an external power source 95. In the example shown in Figure 13, the external power source 95 is an AC power source for normal charging. The external power source 95 outputs AC power such as 200V and supplies AC power to the work vehicle 10 via the cable 92 and the charging adapter 90. The supplied AC power is converted to relatively high voltage (for example, about 350V to 450V) DC power by the onboard charger (OBC) 81, and this DC power is supplied to the battery 20. Note that the external power source 95 may also be a DC power source for rapid charging. In this case, the external power supply 95 outputs high-voltage (for example, around 350V to 450V) DC power, which is supplied to the battery 20 without going through the OBC 81. When rapid charging is performed, a charging start switch is provided near the external power supply 95, and charging can be started in response to the operation of the charging start switch.

[0109] Figure 14 is a flowchart illustrating an example of the operation of a control device (for example, the main ECU 61 shown in Figure 4) when starting up a work vehicle 10. In this example, when the work vehicle 10 is not started, the control device first determines whether or not the starter switch 59 has been operated (step S101). If the starter switch has been operated, the control device determines whether or not the accelerator pedal is pressed down and whether or not the PTO switch is in the OFF position (step S102). If the accelerator pedal is not pressed and the PTO switch is OFF, the control device starts the work vehicle 10 in drive mode. If the accelerator pedal is pressed or the PTO switch is ON, the control device starts the work vehicle 10 in accessory mode (step S104). If it is determined in step S101 that the starter switch 59 has not been operated, the control device determines whether or not the charge mode switch 573 has been operated (step S111). If the charge mode switch has been operated, the control device starts the work vehicle 10 in charge mode (step S112). If the charging mode switch is not operated, the process returns to step S101. The operation shown in Figure 14 is repeated until the work vehicle 10 is started in any mode.

[0110] In charging mode, the control device enables the function of charging the battery 20 from an external power supply 95 via the charging inlet 57. At this time, the control device may display information regarding the charging of the battery 20 (e.g., charge status: SOC) on the meter panel unit 54.

[0111] Figures 15A and 15B show examples of the display on the meter panel unit 54 in charging mode. In this example, the control device displays the charging status of the battery 20 on the display element 113 of the meter panel unit 54. Figure 15A shows an example of the display when the device is in a standby state and charging has not started in charging mode. Figure 15B shows an example of the display when charging is in progress in charging mode. In the standby state, as shown in Figure 15A, an icon indicating that the device is in charging mode, text indicating that it is in a standby state (for example, the word "Ready"), and the current charging status (SOC) of the battery 20 are displayed. When the charging adapter 90 is connected to the socket 571 and charging starts, the control device changes the text to "Charging..." and flashes the icon and text 115 in a conspicuous color (for example, green, blue, red, etc.), as shown in Figure 15B. This display makes it easy for the user to understand the charging status of the battery 20.

[0112] When the work vehicle 10 is operating in charging mode, the user can stop the operation of the work vehicle 10 (turn off the power) by turning off the charging mode switch 573.

[0113] Figure 16 is a block diagram showing an example of a system configuration for realizing the functions of this embodiment. In the example shown in Figure 16, the main ECU 61 functions as the control device described above. The electric ECU 62 and the charging ECU 63 are included in the electric system 98. An ignition relay 93 and a starter relay 94 are connected between the main ECU 61 and the electric system 98. The main ECU 61 performs operations such as boot control, push-start control, self-holding output, and start-up deterrent control. When either the starter switch 59 or the charging mode switch 573 is pressed, the "boot control" first determines which of the starter switch 59 or the charging mode switch 573 was pressed, turns on the ignition relay 93, and starts the power. Next, the "push-start control" uses the switch determination from the "boot control" to determine whether it is in "normal mode" or "charging mode". Start-up deterrent control allows the starter relay 94 to be turned ON only when the system is started in "normal mode," enabling the starter motors 30A, 30B, and other power sources to be started. When started in "charging mode," there is no need to start the power source, so the starter relay 94 is not turned ON. This configuration makes it possible to achieve the aforementioned operation.

[0114] According to this embodiment, the user can start the work vehicle 10 in a charging mode that allows the battery 20 to be charged simply by operating the charging mode switch 573 located near the socket 571 of the charging inlet 57, without having to operate the starter switch 59 which is located away from the charging inlet 57. The user does not need to move to the location of the starter switch 59 to start charging after connecting the charging adapter 90 to the charging inlet 57, thus greatly improving convenience. The user can also end the charging mode and turn off the power to the work vehicle 10 by operating (for example, pressing and holding) the charging mode switch 573 while in charging mode.

[0115] In the example shown in Figure 14, when the starter switch 59 is turned on, the starting mode (drive mode or accessory mode) is determined by whether the conditions in step S102 are met. However, this is only one example. For example, the starting mode (drive mode or accessory mode) may be determined by whether the brake pedal is pressed, the number of times the starter switch 59 is pressed, or the duration for which the starter switch 59 is pressed. Alternatively, the work vehicle 10 may be configured to always start in drive mode when the starter switch 59 is turned on, without implementing an accessory mode.

[0116] Next, an example of a configuration in which the work vehicle 10 can operate in a minute movement mode or a height adjustment mode will be described.

[0117] Figure 17 is a side view showing an example of a work vehicle 10 capable of operating in minute movement mode or height adjustment mode. Figure 17 also shows a work implement 300 (agricultural implement) connected to the work vehicle 10. The work implement 300 is connected to the rear of the work vehicle 10 via a coupling device such as a three-point link 108 (also referred to as a "three-point hitch"). The work vehicle 10 shown in Figure 17 is equipped with an operating unit 96 for operating minute movement or height adjustment of the work implement 300. The operating unit 96 is located away from the starter switch, which is near the steering wheel 53. In the example in Figure 17, the operating unit 96 is located at the rear of the work vehicle 10.

[0118] The operating unit 96 is used to move the work vehicle 10 forward or backward at a small speed, or to raise or lower the three-point link 108. Even when the work vehicle 10 is not running, the user can start the work vehicle 10 in a restricted mode by operating the operating unit 96, allowing the work vehicle 10 to move forward or backward at a low speed, or to adjust the height of the three-point link 108. These functions are used to adjust the position of the work vehicle 10 or the height of the three-point link 108, for example, to attach or detach the work implement 300 or to adjust the position of the work implement 300. By providing such functions, the user can start the work vehicle 10 for position adjustment of the work vehicle 10 or the work implement 300 without having to move to the driver's seat 52 and operate the starter switch.

[0119] Figure 18A shows an example of an operating unit 96. The operating unit 96A shown in Figure 18A includes a minute-movement mode switch 191, a minute-forward switch 192, and a minute-reverse switch 193, which enable the function of moving the work vehicle 10 forward or backward at a minute speed. The minute-forward switch 192 and the minute-reverse switch 193 are located near (below in the figure) the minute-movement mode switch 191. In this example, the minute-movement mode switch 191, the minute-forward switch 192, and the minute-reverse switch 193 are all push-button switches.

[0120] The user can start the work vehicle 10 in minute-movement mode by pressing the minute-movement mode switch 191 while the work vehicle 10 is not powered on. In minute-movement mode, the user can move the work vehicle 10 forward at a low speed (e.g., less than 1 km / h) by pressing the minute-forward switch 192. The user can also move the work vehicle 10 backward at a low speed (e.g., less than 1 km / h) by pressing the minute-reverse switch 193. The movement speed of the work vehicle 10 in minute-movement mode may be set by the user. The work vehicle 10 will continue to move forward or backward while the user continues to press the minute-forward switch 192 or minute-reverse switch 193, and the work vehicle 10 will stop when the user releases the switch. In minute-movement mode, the user can also exit minute-movement mode and turn off the power to the work vehicle 10 by operating the minute-movement mode switch 191 (e.g., by long-pressing it).

[0121] In this embodiment, when the work vehicle 10 is not running, the control device starts the work vehicle 10 in response to the operation of the minute-movement mode switch 191 and starts operation in minute-movement mode. In minute-movement mode, the control device controls one or more electric motors (for example, the first electric motor 30A shown in Figure 4) in response to the operation of the minute-forward switch 192 to move the work vehicle 10 forward at a minute speed. The control device also controls one or more electric motors (for example, the first electric motor 30A shown in Figure 4) in response to the operation of the minute-reverse switch 193 to move the work vehicle 10 backward at a minute speed. In minute-movement mode, the control device activates the operation of the first electric motor 30A and the second electric motor 30B, but limits their rotational speed to be less than the rotational speed in drive mode. The second electric motor 30B is driven to supply hydraulic fluid to the hydraulic clutch.

[0122] Figure 19 is a flowchart showing an example of operation by the control device of a work vehicle 10 capable of operating in minute movement mode. The operation of steps S101-S104 in the flowchart shown in Figure 19 is the same as the operation of the corresponding steps shown in Figure 14. In the example of Figure 19, if it is determined in step S101 that the starter switch has not been operated, the control device determines whether the minute movement mode switch 191 has been operated (step S121). If the minute movement mode switch 191 has been operated, the control device starts the work vehicle 10 in minute movement mode. If the minute movement mode switch 191 has not been operated, the process returns to step S101. In minute movement mode, the control device moves the work vehicle 10 forward at a low speed while the minute forward switch 192 is pressed, and moves the work vehicle 10 backward at a low speed while the minute reverse switch 193 is pressed. In minute movement mode, if the minute movement mode switch 191 is operated (for example, long-pressed), the control device terminates minute movement mode and turns off the power to the work vehicle 10 again.

[0123] Figure 18B shows another example of the operating unit 96. The operating unit 96B shown in Figure 18B includes a height adjustment mode switch 196, an upward switch 197, and a downward switch 198 that enable the raising and lowering function of the three-point link 108. The upward switch 197 and the downward switch 198 are located near the height adjustment mode switch 196 (to the right in the figure). In this example, the height adjustment mode switch 196, the upward switch 197, and the downward switch 198 are all push-button switches.

[0124] The user can start the work vehicle 10 in height adjustment mode by pressing the height adjustment mode switch 196 while the work vehicle 10 is not powered on. In height adjustment mode, the user can raise the three-point link 108 by pressing the raise switch 197. The user can also lower the three-point link 108 by pressing the lower switch 198. The raising and lowering speeds of the three-point link 108 in height adjustment mode may be set by the user. The three-point link 108 will continue to rise or lower while the user continues to press the raise switch 197 or lower switch 198, and will stop when the user releases the switch. In height adjustment mode, the user can also exit height adjustment mode and turn off the power to the work vehicle 10 by operating the height adjustment mode switch 196 (for example, by long-pressing it).

[0125] In this embodiment, when the work vehicle 10 is not running, the control device starts the work vehicle 10 in response to the operation of the height adjustment mode switch 196 and starts operation in height adjustment mode. In height adjustment mode, the control device raises the three-point link 108 in response to the operation of the rise switch 197 and lowers the three-point link 108 in response to the operation of the lower switch 198. In this embodiment, the hydraulic system that drives the three-point link 108 is driven by the second electric motor 30B. In height adjustment mode, the control device disables the operation of the first electric motor 30A and enables the operation of the second electric motor 30B.

[0126] Figure 20 is a flowchart showing an example of operation by the control device of a work vehicle 10 that can operate in height adjustment mode. The operations of steps S101-S104 in the flowchart shown in Figure 20 are the same as the operations of the corresponding steps shown in Figure 14. In the example of Figure 20, if it is determined in step S101 that the starter switch has not been operated, the control device determines whether the height adjustment mode switch 196 has been operated (step S131). If the height adjustment mode switch 196 has been operated, the control device starts the work vehicle 10 in height adjustment mode. If the height adjustment mode switch 196 has not been operated, the process returns to step S101. In height adjustment mode, the control device raises the three-point link 108 while the rise switch 197 is pressed, and lowers the three-point link 108 while the fall switch 198 is pressed. In height adjustment mode, if the height adjustment mode switch 196 is operated (for example, long-pressed), the control device exits height adjustment mode and turns off the power to the work vehicle 10 again.

[0127] In the examples of Figures 18A and 19, the minute movement mode is implemented independently, and in the examples of Figures 18B and 20, the height adjustment mode is implemented independently, but both may be implemented together. In that case, the operating unit 96 shown in Figure 17 may include both a group of switches for the minute movement mode and a group of switches for the height adjustment mode, for example, as shown in Figure 18C. Furthermore, the functions of the minute movement mode and / or the height adjustment mode may be combined with the functions of the charging mode, which were described with reference to Figures 12 to 15B. In that case, when the work vehicle 10 is not running, the control device responds to the operation of one of the charging mode switch, minute movement mode switch, or height adjustment mode switch and starts the work vehicle 10 in a specific mode corresponding to that operation. In that specific mode, at least a part of the normal driving or PTO shaft driving operations are disabled, and only the necessary functions according to the selected mode are enabled.

[0128] The functions related to the minute movement mode and height adjustment mode, as described with reference to Figures 17 to 20, are applicable not only to electric vehicles driven by electric motors but also to work vehicles driven by internal combustion engines such as diesel engines. Therefore, the technology of this disclosure is not necessarily limited to a form applicable to electric work vehicles. Furthermore, the functions related to the charging mode are also applicable to hybrid electric vehicles equipped with an internal combustion engine as a power source in addition to an electric motor.

[0129] As described above, according to the embodiments of this disclosure, the work vehicle 10 is provided with specific mode switches, such as a charging mode switch, a minute movement mode switch, or a height adjustment switch, located away from the starter switch used during normal startup. By operating the specific mode switch, the user can start the work vehicle 10 and activate the necessary functions without operating the starter switch. This makes it easy to perform operations such as charging, minute movements of the work vehicle 10, or height adjustment of the three-point linkage, greatly improving convenience.

[0130] The present invention can be applied to agricultural tractors equipped with electric motors for driving, and to electric work vehicles such as construction vehicles.

[0131] 10...Work vehicle, 11...Body, 12...Front frame, 13...Transmission case, 14...Wheels, 14F...Front wheels, 14R...Rear wheels, 15F...Front axle, 15R...Rear axle, 16...Housing frame, 17F...Front axle case, 17R...Rear axle case, 19...Front housing, 20...Battery, 22...Battery management system (BMS), 24...Temperature sensor, 30, 30A, 30B...Electric motor, 33...Output shaft, 34...Power transmission system, 35A, 35B...Inverter, 36...Hydraulic pump, 40...PTO shaft, 51...Rops frame, 52...Driver's seat, 53...Steering wheel, 54...Meter panel unit, 55...Pedal group, 56...Switch group, 57...Charging inlet, 58...Power converter, 60... High-voltage equipment cooling system, 61... Main ECU, 62... Electric ECU, 63... Charging ECU, 64... Relay, 65... High-voltage equipment radiator, 66... ​​Reservoir tank, 67... Pump, 68... Cooling fan, 70... Battery temperature control system, 72... Heater, 75... Battery radiator, 76... Reservoir tank, 77... Pump, 80... Power distribution unit, 81... Onboard charger (OBC), 82... DC-DC converter, 90... Charging adapter, 95... External power supply, 102A, 102B, 102C... Indicator needle, 110... Meter section, 111... First analog meter, 112... Second analog meter, 113... Display element, 140A, 140B... Arc-shaped indicator, 571... Socket, 573... Charging mode switch

Claims

1. An electric work vehicle comprising: a travel device; a PTO shaft for supplying power to a work machine; one or more electric motors for driving the travel device and the PTO shaft; a starter switch for starting the work vehicle; a specific mode switch located away from the starter switch for activating a specific function in the work vehicle; and a control device for controlling the operation of the work vehicle, wherein the control device, when the work vehicle is not started, starts the work vehicle in response to the operation of the starter switch and starts operation in a drive mode in which the travel device and the PTO shaft can be driven by the one or more electric motors; and when the work vehicle is not started, starts the work vehicle in response to the operation of the specific mode switch and starts operation in a specific mode that activates the specific function.

2. The work vehicle according to claim 1, further comprising: a battery for storing power supplied to one or more electric motors; and a charging inlet to which a charging adapter for charging the battery from an external power source is connected, wherein the specific mode is a charging mode that enables the function of charging the battery from the external power source via the charging inlet; the specific mode switch is a charging mode switch for starting the charging mode; and the control device, when the work vehicle is not started, starts the work vehicle in response to the operation of the charging mode switch and starts operation in the charging mode.

3. The work vehicle according to claim 2, further comprising a meter panel unit for displaying the status of the work vehicle, wherein the control device causes the meter panel unit to display the charging status of the battery in the charging mode.

4. The work vehicle according to claim 2, wherein the charging mode switch is located near the charging inlet.

5. The work vehicle according to claim 1, wherein the specific mode is a minute-movement mode that enables the function of moving the work vehicle forward or backward at a minute speed, the specific mode switch is a minute-movement mode switch for starting the minute-movement mode, and the control device starts the work vehicle and starts operation in the minute-movement mode in response to the operation of the minute-movement mode switch when the work vehicle is not started.

6. A work vehicle according to claim 5, wherein a minute forward switch and a minute reverse switch are provided near the minute movement mode switch, and the control device, in the minute movement mode, controls one or more electric motors to move the work vehicle forward at a minute speed in response to the operation of the minute forward switch, and controls one or more electric motors to move the work vehicle backward at a minute speed in response to the operation of the minute reverse switch.

7. The work vehicle according to claim 1, further comprising a three-point linkage supporting the work machine, wherein the specific mode is a height adjustment mode that enables the raising and lowering function of the three-point linkage, the specific mode switch is a height adjustment mode switch for starting the height adjustment mode, and the control device starts the work vehicle and starts operation in the height adjustment mode in response to the operation of the height adjustment mode switch when the work vehicle is not started.

8. The work vehicle according to claim 7, wherein an upward switch and a downward switch are provided near the height adjustment mode switch, and the control device, in the height adjustment mode, raises the three-point link in response to operation of the upward switch and lowers the three-point link in response to operation of the downward switch.

9. The work vehicle according to claim 7, further comprising a hydraulic system for driving the three-point linkage, wherein the one or more electric motors include an electric motor for driving the hydraulic system.

10. The work vehicle according to claim 1, wherein the control device disables the operation of the one or more electric motors in the specific mode.

11. The work vehicle according to any one of claims 1 to 10, wherein the one or more electric motors include a first electric motor for driving the travel device and a second electric motor for driving the PTO shaft.

12. A method performed by a computer controlling a work vehicle, wherein the work vehicle comprises a travel device, a PTO shaft for supplying power to a work machine, one or more electric motors for driving the travel device and the PTO shaft, a starter switch for starting the work vehicle, and a specific mode switch located away from the starter switch for activating a specific function in the work vehicle, the method comprising: starting the work vehicle in response to the operation of the starter switch when the work vehicle is not started, and starting operation in a drive mode that enables the driving of the travel device and the PTO shaft by the one or more electric motors; and starting the work vehicle in response to the operation of the specific mode switch when the work vehicle is not started, and starting operation in a specific mode that enables the specific function.

13. A computer program executed by a computer that controls a work vehicle, wherein the work vehicle comprises a travel device, a PTO shaft that supplies power to a work machine, one or more electric motors that drive the travel device and the PTO shaft, a starter switch for starting the work vehicle, and a specific mode switch located away from the starter switch for activating a specific function in the work vehicle, and the computer program causes the computer to: start the work vehicle in response to the operation of the starter switch when the work vehicle is not started, and start operation in a drive mode in which the travel device and the PTO shaft can be driven by the one or more electric motors; and start the work vehicle in response to the operation of the specific mode switch when the work vehicle is not started, and start operation in a specific mode in which the specific function is activated.

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