electric work vehicle

Abstract

To provide an electric work vehicle that can notify a driver of information on whether starting of an electric motor is appropriate or not.SOLUTION: An electric work vehicle includes: a drive control unit 6B configured to control driving of an electric work vehicle; a display unit 70 configured to display vehicle state information of the electric work vehicle; and a notification control unit 7 configured to control a display on the display unit 70. The display unit 70 is provided with a start permission determination display body configured to indicate a start permission for an electric motor 1. The drive control unit 6B is provided with a start determination unit 62 configured to perform start permission determination for the electric motor. The notification control unit 7 is configured to generate a display control signal to the start permission determination display body based on the determination result of the start determination unit 62.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to an electric work vehicle driven by the power of an electric motor powered by a rechargeable battery.

Background Art

[0002] Since an electric work vehicle is a traveling vehicle that uses a battery and an electric motor as power sources, battery information regarding the state of the battery and electric motor information regarding the state of the electric motor are important. Therefore, this battery information and electric motor information need to be notified to the administrator (driver) of the electric work vehicle. In the electric work vehicle described in Patent Document 1, the remaining capacity of the battery is displayed on a display device.

[0003] In the rechargeable electric vehicle described in Patent Document 2, operation information is displayed on the display unit of the display device. The operation information includes the vehicle cumulative operation time, and information regarding the driving battery, namely, the temperature of the driving battery, the remaining battery amount, and the estimated operable time. Further, when the electric vehicle is in the normal charging mode or the rapid charging mode, the remaining battery amount, the elapsed time and the remaining time regarding charging, information indicating that it is in normal charging or rapid charging, and information indicating the progress of charging are displayed. Also, by the driver operating the operation unit of the display device, it is possible to display the voltage, temperature, or current of the driving battery. Further, in this rechargeable electric vehicle, a display lamp is provided that determines the inoperability of the electric motor caused by an abnormality in the driving battery or an abnormality in the high-voltage circuit, and displays the determination result.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] In electric work vehicles, even if the electric motor is operational, starting the electric motor may be inappropriate for safety reasons. Therefore, it would be beneficial to not only determine whether the electric motor is operational, but also to determine whether the current state of the electric work vehicle is suitable for starting the electric motor; in other words, to determine whether the timing of starting the electric motor is appropriate. However, conventional electric work vehicles, such as those described in Patent Documents 1 and 2, do not consider the technical concept of displaying the result of the determination of whether the electric motor starting timing is appropriate. As a result, there is a problem in that drivers unfamiliar with electric work vehicles may start the electric motor even when it should not be started. [Means for solving the problem]

[0006] The electric work vehicle according to the present invention has an electric motor powered by a rechargeable battery. output Powered by Driving An electric work vehicle, the electric Motor output The system includes a drive control unit for controlling the motor, a display unit for displaying vehicle status information of the electric work vehicle, and a notification control unit for controlling the display on the display unit. The display unit is a start permission indicator that shows permission to start the electric motor. The system includes an output limit indicator that shows the output limit when the output of the electric motor is limited, The system includes a key device for starting the electric motor, The drive control unit includes a start determination unit that determines whether to allow the electric motor to start. Furthermore, an output limiting unit that limits the output of the electric motor to a previously set limiting output value when the battery condition deteriorates due to a decrease in battery voltage or an increase in battery temperature. Equipped with, The aforementioned notification control unit is During the start operation using the aforementioned key device, The determination result of the start determination unit and limitations of the output limiting unit Based on the start permission indicator and the output limit indicator Generates display control signals for the target.

[0007] In this configuration, the start determination unit of the drive control unit that controls the drive of the electric work vehicle determines whether or not to allow the electric motor to start. If the determination result is that the start is permitted, the start permission indicator on the display unit displays that the electric motor is permitted to start. In other words, information regarding whether or not the electric motor should be started is communicated to the driver through the start permission indicator. If the start permission indicator shows that the electric motor is permitted to start, the driver will start the electric motor; if the start permission indicator does not show that the start is permitted, the driver will not start the electric motor. This allows the driver to start the electric motor at the appropriate time.

[0008] A particularly inappropriate timing for starting an electric motor is during battery charging. Therefore, in this invention, the starting determination unit determines that starting is prohibited when the battery is being charged.

[0009] In one embodiment of the present invention, the display unit includes a charging indicator that shows the charging status of the battery, the charging indicator displays "normal charging" during normal charging and "abnormal charging completed" when abnormal charging is completed. In this configuration, the display unit is equipped with a charging indicator that shows the charging status of the battery in addition to a start permission indicator, so the driver can understand not only the starting timing of the electric motor but also the charging status that affects the operation of the electric motor.

[0010] In another embodiment of the present invention, the display unit includes an electric drive warning indicator that displays an error in the electric drive system and a vehicle condition warning indicator that displays a vehicle condition error. In this configuration, the driver can understand through the display unit that there is a problem with the electric drive system, including the electric motor of the electric work vehicle, and that there is a problem with the vehicle condition of the electric work vehicle.

[0011] In a more preferred embodiment of the present invention, the display unit comprises a battery level indicator that displays the remaining battery level of the battery and a battery temperature indicator that displays the temperature of the battery. The fact that the battery level and battery temperature, which are the first things the driver must pay attention to when managing the battery, are displayed through the display unit along with other information is advantageous for understanding the overall status of the electric work vehicle.

[0012] Depending on the state of the electric drive system, which is determined by the driving conditions, working conditions, charging conditions, etc., even if the operation of the electric motor is inappropriate, it may be permitted to operate the electric motor at a low output. Furthermore, for emergency evacuation, etc., it is necessary to continue the operation of the electric motor even if it is limited to a low output. It is preferable that the driver is aware of the operation of the electric motor under such low output restrictions. For this reason, in the present invention, the drive control unit is equipped with an output limiting unit that limits the output of the electric motor based on the state of the electric drive system, and the display unit is equipped with an output limiting indicator that shows the output limit when the output of the electric motor is limited.

[0013] While displaying various information on the display unit offers the advantages described above, the driver must keep their eyes fixed on the road ahead, and sunlight shining on the display unit can make it difficult to see. To address these problems, the present invention provides the driver with voice notifications of information to be reported via an audio notification device from the notification control unit. In particular, when an abnormality occurs, an audio warning is given to report the abnormality. In this configuration, visual and audio information is conveyed to the driver both visually and aurally, thus suppressing the inconvenience of interruptions in the driver's notification information. [Brief explanation of the drawing]

[0014] [Figure 1] This is a left side view of the tractor. [Figure 2] This is a left side view showing the arrangement of the motor and the traction battery. [Figure 3] This is a schematic diagram showing the flow of power transmission. [Figure 4] It is a front view of the steering wheel and the front panel. [Figure 5] It is a front view of the meter panel. [Figure 6] It is a functional block diagram showing the functional parts of the battery system.

Embodiments for Carrying Out the Invention

[0015] The embodiments for carrying out the present invention will be described based on the drawings. In the following description, unless otherwise specified, the direction of arrow F in the drawings is taken as “front”, the direction of arrow B as “rear”, the direction of arrow L as “left”, and the direction of arrow R as “right”. The direction of arrow U in the drawings is taken as “up” and the direction of arrow D as “down”.

[0016] 〔Overall Configuration of Tractor〕 Hereinafter, a tractor as an example of the electric working vehicle according to the present invention will be described. As shown in FIG. 1, the tractor includes left and right front wheels 10, left and right rear wheels 11, and a cover member 12.

[0017] The tractor includes a body frame 2 and an operation unit 3. The body frame 2 is supported by the left and right front wheels 10 and the left and right rear wheels 11. The cover member 12 is disposed at the front of the body. The operation unit 3 is disposed behind the cover member 12.

[0018] The operation unit 3 has a protection frame 30, an operation seat 31, and a steering wheel 32 The steering wheel 32 can be operated by a driver who boards the operation unit 3 and sits on the operation seat 31. By operating the steering wheel 32, the left and right front wheels 10 are steered. In front of the operation seat 31, a front panel 13 is provided, and a part of the front panel 13 is formed as a meter panel 13a. The driver can perform various driving operations in the operation unit 3.

[0019] The tractor is equipped with a battery 4, which is a traction battery. The cover member 12 is pivotable around an opening / closing axis Q that runs along the left-right direction of the machine body. When the cover member 12 is closed, the battery 4 is covered by the cover member 12. A charging cover 12a is pivotably provided on the left side of the front portion of the cover member 12. When this charging cover 12a is opened, the charging power connection part 44 into which the power supply cable is inserted during charging is exposed.

[0020] As shown in Figure 2, the tractor is equipped with an inverter 14 and an electric motor 1. The battery 4 supplies power to the inverter 14. The inverter 14 converts the DC power from the battery 4 into AC power to generate drive power supplied to the electric motor 1. The drive power is the AC power generated by the inverter 14.

[0021] As shown in Figures 2 and 3, the tractor is equipped with a hydrostatic continuously variable transmission 15 and a transmission 16. As shown in Figure 3, the hydrostatic continuously variable transmission 15 has a hydraulic pump 15a and a hydraulic motor 15b.

[0022] The hydraulic pump 15a is driven by rotational power from the electric motor 1. When the hydraulic pump 15a is driven, rotational power is output from the hydraulic motor 15b. The hydrostatic continuously variable transmission 15 is configured so that the rotational power between the hydraulic pump 15a and the hydraulic motor 15b is continuously variable.

[0023] The rotational power output from the hydraulic motor 15b is transmitted to the transmission 16. The rotational power transmitted to the transmission 16 is shifted by the gear-type transmission mechanism of the transmission 16 and distributed to the left and right front wheels 10 and the left and right rear wheels 11. As a result, the left and right front wheels 10 and the left and right rear wheels 11 are driven.

[0024] As shown in Figure 3, the tractor is equipped with a mid-PTO shaft 17 and a rear PTO shaft 18. The rotational power output from the electric motor 1 is distributed to the hydraulic pump 15a, the mid-PTO shaft 17, and the rear PTO shaft 18. This causes the mid-PTO shaft 17 and the rear PTO shaft 18 to rotate.

[0025] If a working device is connected to the mid-PTO shaft 17 or the rear PTO shaft 18, the working device will be driven by the rotational power of the mid-PTO shaft 17 or the rear PTO shaft 18. For example, as shown in Figure 2, in this embodiment, a grass cutting device 19 is connected to the mid-PTO shaft 17. The grass cutting device 19 is driven by the rotational power of the mid-PTO shaft 17.

[0026] Figure 4 shows the steering wheel 32 and the front panel 13, and Figure 5 shows the meter panel 13a incorporated into the front panel 13. The meter panel 13a is configured as a display unit 70 that informs the driver of various information. The display unit 70 comprises a left LED display unit 70L, a right LED display unit 70R, a central LED display unit 70C, and a liquid crystal display unit 70D. The left LED display unit 70L, the right LED display unit 70R, and the central LED display unit 70C surround the liquid crystal display unit 70D from below.

[0027] The left LED display unit 70L includes the left turn signal LED 71a, the battery LED 71b for electrical components, the parking brake LED 71c, the master warning LED 71d, etc. The left turn signal LED 71a is an indicator that indicates a left turn. The battery LED 71b for electrical components is an indicator that indicates the status of the battery 41 for electrical components (see Figure 6). The parking brake LED 71c is an indicator that indicates whether the parking brake is ON or OFF. The master warning LED 71d is a vehicle status warning indicator that lights up based on vehicle status information generated when a vehicle status error indicating an abnormality in the battery control system, electric drive system, or mechanical control system is detected.

[0028] The right LED display unit 70R includes a right turn signal LED 72a, a battery LED 72b, a battery temperature LED 72c, a coolant temperature LED 72d, etc. The right LED display unit 70R is an indicator that indicates a turn to the right. The battery LED 72b is an indicator that warns of the status of the battery 4, which is the power source for the electric motor 1, especially low voltage. The battery temperature LED 72c is an indicator that warns of high temperature of the battery 4. The coolant temperature LED 72d is an indicator that warns of high temperature of the coolant that cools the inverter 14, etc.

[0029] The central LED display unit 70C includes a start permission LED 73a, a charging status LED 73b, an output limit LED 73c, an electric system LED 73d, etc. The start permission LED 73a is used as a start permission indicator that lights up when the electric motor 1 is permitted to start, and displays the word "READY". Since driving is prohibited while the battery 4 is charging, the start permission LED 73a is turned off. The charging status LED 73b, which shows the shape of the outlet, is used as a charging indicator that shows the charging status of the battery 4. When the power supply cable is plugged into the charging power connection unit 44 and the charging control process starts, the charging status LED 73b lights up. Furthermore, the charging status LED 73b displays normally (lights up) during normal charging and displays abnormal charging completion (fast blinking) when abnormal charging is completed. The output limit LED 73c is used as an output limit indicator that lights up when the output of the electric motor 1 is limited due to the state of the battery 4 or inverter 14. The electric system LED 73d is used as an electric drive warning indicator and lights up when an abnormality occurs in the electric drive system, including the electric motor 1.

[0030] The liquid crystal display unit 70D includes a battery level display area 74a, a battery temperature display area 74b, a rotation speed display area 74c, a multi-purpose display area 74d, and the like. The battery level display area 74a is formed as a segment bar graph and is used as a battery level indicator that displays the battery level of battery 4 in stages. The battery temperature display area 74b is also formed as a segment bar graph and is used as a battery temperature indicator that displays the battery temperature of battery 4 in stages. The rotation speed display area 74c and the multi-purpose display area 74d are 7-segment displays commonly used for digital numerical displays. The multi-purpose display area 74d is normally used as an hour meter or a battery consumption meter per trip, but displays an error code when an error occurs.

[0031] As shown in Figure 6, the display unit 70 is controlled by display control signals from the notification control unit 7 to the display unit 70. The notification control unit 7 is connected to the control unit 6 and generates display control signals based on notification commands from the control unit 6. The notification control unit 7 controls the display unit 70 incorporated in the meter panel 13a and the voice notification device 80 that outputs voice warnings such as warning sounds and artificial voices, and provides visual or audible notification of driving status, work status, battery status (charge level and temperature), whether or not the vehicle can be started, etc.

[0032] [Motor and battery control system configuration] Figure 6 schematically shows the configuration for controlling the battery 4 and the electric motor 1. The motor-battery control system includes an accelerator device 33, a key device 34, a control unit 6, and an inverter 14. The control unit 6 controls the operation of the electric motor 1. The accelerator device 33 is located in the driver's unit 3. Although the structure of the accelerator device 33 is not shown, it includes a swingable lever and a potentiometer operated by the swinging operation of the lever. The accelerator device 33 is connected to the control unit 6. The key device 34 is also connected to the control unit 6. The key device 34 is located on the front panel 13 and performs ON operation (power connection) and OFF operation (power disconnection) of the control unit 6.

[0033] The control unit 6 is further connected to the inverter 14 and, in response to commands from the accelerator device 33, issues drive commands to the inverter 14. The inverter 14 controls the output of the electric motor 1 by adjusting the power supplied from the battery 4 to the electric motor 1 in response to commands from the control unit 6.

[0034] The battery 4 is charged by the charging control unit 43 from a power supply device 45 connected to the charging power connection unit 44. The charging power connection unit 44 is provided with a power supply socket, and during charging, the power supply socket is connected to the power supply connector of the charging cable from the power supply device 45.

[0035] Battery 4 is, for example, a lithium-ion battery, and is composed of a large number of battery cells 40, which are small, low-voltage unit batteries, stacked together. The battery state detection unit 5, which detects the battery state, includes a battery voltage detector 51 and a battery temperature detection unit 52. The battery voltage detector 51 can detect the voltage at the connection point between multiple battery cells 40 connected in series as the cell voltage. The detection signals from the battery voltage detector 51 and the battery temperature detection unit 52 are sent to the control unit 6.

[0036] In addition to the battery 4, the tractor is also equipped with an electrical component battery 41 that supplies power to the control unit 6 and other electrical components. The electrical component battery 41 supplies low voltage (12 volts) power to drive the electrical components. The electrical component battery 41 is charged by power supplied from the battery 4 via a DC / DC converter 42. The DC / DC converter 42 is driven and controlled by the control unit 6. The charge state of the electrical component battery 41 is also managed by the control unit 6.

[0037] The control unit 6 includes a charging control unit 6A and a drive control unit 6B as functional elements particularly relevant to the present invention. The charging control unit 6A controls the charging and discharging of the battery 4. The drive control unit 6B controls the drive of the tractor.

[0038] The charging control unit 6A has a battery management unit 60. The battery management unit 60 enters charging mode when it detects that the power connector of the charging cable from the power supply device 45 has been inserted into the power supply socket of the charging power connection unit 44. When the battery management unit 60 sends a charging start command to the charging control unit 43, the charging program of the charging control unit 43 is executed and the battery 4 is charged. When charging is completed appropriately, the control unit 6 enters a dormant state and the power is cut off. If an error occurs during this charging process, the battery management unit 60 generates error information and sends it to the notification control unit 7.

[0039] The drive control unit 6B includes a motor control unit 61, a start determination unit 62, and an output limiting unit 63. The motor control unit 61 controls the drive of the electric motor 1. Specifically, it generates a drive signal to drive the electric motor 1 based on a signal from the accelerator device 33 and provides it to the inverter 14. The start determination unit 62 determines whether to allow the electric motor 1 to start based on start permission determination rules. For example, start permission determination rules include "do not start when the battery 4 is being charged," "allow start if there is no problem with the electric drive control system when the ON operation is performed by the key device 34," and "do not start if the battery condition exceeds a limit value, such as a drop in battery voltage or a rise in battery temperature." The determination result from the start determination unit 62 is sent to the notification control unit 7 and used to control the display of the start permission LED 73a, which is a start permission indicator on the display unit 70.

[0040] The output limiting unit 63 issues an output limiting command to the motor control unit 61 to limit the output of the electric motor 1 to a previously set limiting output value when the battery condition deteriorates, such as when the battery voltage drops or the battery temperature rises. When the output limiting of the electric motor 1 is executed, the notification control unit 7 lights up the output limiting LED 73c, which is the output limiting indicator of the display unit 70.

[0041] [Another embodiment] (1) Whether to prohibit starting during charging may be determined when the charging cable from the power supply device 45 is connected to the charging power connection part 44, or it may be determined when the charging process is actually performed.

[0042] (2) The form of each display element in the display unit 70 is not limited to the form shown in Figure 5. Its arrangement may also be, at least partially, in a location other than the front panel 13. Furthermore, at least part or all of the notification control unit 7, the display unit 70, and the voice notification device 80 may be composed of a general-purpose terminal such as a tablet computer.

[0043] (3) Each functional block in the functional block diagram shown in Figure 5 may be divided into multiple parts, or multiple functional blocks may be integrated.

[0044] Furthermore, the configurations disclosed in the above embodiments (including other embodiments, the same applies hereinafter) can be applied in combination with configurations disclosed in other embodiments, as long as no inconsistencies arise. Moreover, the embodiments disclosed herein are illustrative, and the embodiments of the present invention are not limited thereto, and can be modified as appropriate without departing from the object of the present invention. [Industrial applicability]

[0045] This invention is not limited to tractors, but can be applied to various electric work vehicles such as rice transplanters, combine harvesters, and construction machinery. [Explanation of symbols]

[0046] 1: Electric motor 4: Battery 43: Charging control unit 44: Charging power connection section 5: Battery status detection unit 51: Battery voltage detector 52: Battery temperature detection unit 6: Control Unit 6A: Charging control unit 60: Battery Management Department 6B: Drive control unit 61: Motor control unit 62: Startup determination unit 63: Output limiting section 7: Notification control unit 70: Display Unit 70C: Central LED display section 70D: Liquid crystal display 70L:Left LED display section 70R: Right LED display section 71d: Master warning LED (vehicle status warning indicator) 72b: Battery LED (charging indicator) 73a: Start-up permission LED (start-up permission indicator) 73b: Charging status LED 73c: Output limiting LED (output limiting indicator) 73d: Electrical LED (Drive System Warning Indicator) 13a: Meter panel 74a: Battery level display area (battery level indicator) 74b: Battery temperature display area (battery temperature indicator) 80: Voice notification device

Claims

1. An electric work vehicle that is driven by the output power of an electric motor supplied from a rechargeable battery, The system includes a drive control unit that controls the output of the electric motor, a display unit that displays vehicle status information of the electric work vehicle, and a notification control unit that controls the display on the display unit. The display unit comprises a start permission indicator that shows permission to start the electric motor, an output limit indicator that shows the output limit when the output of the electric motor is limited, and a key device for starting the electric motor. The drive control unit includes a start determination unit that determines whether to allow the electric motor to start, and an output limiting unit that limits the output of the electric motor to a previously set limiting output value when the battery condition deteriorates due to a decrease in battery voltage or an increase in battery temperature. The notification control unit generates display control signals for the start permission indicator and the output limit indicator based on the determination result of the start determination unit and the limit of the output limit unit when the start operation is performed by the key device, for an electric work vehicle.

2. The electric work vehicle according to claim 1, wherein the starting determination unit determines that starting is prohibited when the battery is being charged.

3. The electric work vehicle according to claim 1, wherein the display unit comprises a charging indicator that shows the charging status of the battery, the charging indicator displays "normal charging" when normal charging is in progress, and displays "abnormal charging completed" when abnormal charging is completed.

4. The electric work vehicle according to claim 1, wherein the display unit comprises an electric drive warning indicator for displaying errors in the electric drive system and a vehicle status warning indicator for displaying vehicle status errors.

5. The electric work vehicle according to claim 1, wherein the display unit comprises a battery level indicator that displays the remaining battery level of the battery and a battery temperature indicator that displays the temperature of the battery.

6. The electric work vehicle according to any one of claims 1 to 5, wherein the notification control unit notifies the driver of information to be notified by voice via an audio notification device.

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