electric work vehicle

Abstract

To provide an electric working vehicle that can properly travel or start working, even in a state where a motor is rotating at a speed of 0 rpm or at a minimum speed.SOLUTION: An electric working vehicle is provided with: a motor M that drives at least either of travelling devices (10 and 11) and a working device; speed changers (38 and 39) that perform operation of changing a speed of rotative power for driving the travelling devices (10 and 11) or the working device; an accelerator operating tool 37 that performs operation of increasing / decreasing a motor rotating speed of the motor M; and a motor control part 54 that controls the motor rotating speed in accordance with operation to the accelerator operating tool 37. When operating the speed changers (38 and 39) and the accelerator operating tool 37 by an improper procedure, in a state where the motor rotating speed is below a predetermined first rotating speed, the motor control part 54 executes motor suppression control by which output of the motor M is restricted.SELECTED DRAWING: Figure 5

Description

Technical Field

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[0001] The present invention relates to an electric working vehicle in which a traveling device is driven by a motor.

Background Art

[0002] As shown in Patent Document 1, an electric tractor (electric working vehicle) drives a traveling device by a motor and also drives a working device. An electric working vehicle such as an electric tractor includes various operation tools, and based on operations on the various operation tools, a motor or the like is controlled to perform traveling and working.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, the motor can standby in a state where the rotational speed is 0 rpm. If an operation is performed in an incorrect procedure from the state where the rotational speed of the motor is 0 rpm, the vehicle body may suddenly start moving forward, and it may not be possible to appropriately start traveling or working. <​​​​​​​​To achieve the above objective, an electric work vehicle according to one embodiment of the present invention comprises a motor that drives at least one of a traveling device and a work device, a speed control device that changes the speed of the rotational power driving the traveling device or the work device, an accelerator device that raises or lowers the motor speed of the motor, and a motor control unit that controls the motor speed in response to the operation of the accelerator device, wherein the motor control unit is operated when the speed control device is operated to the traveling position before the accelerator device is operated, and thereafter While the motor rotation speed is less than or equal to a predetermined first rotation speed When the accelerator pedal is operated, motor suppression control is implemented to restrict the output of the motor.

[0007] When starting the machine, if the gear shift and accelerator controls are operated improperly while the motor is running at low RPM, the machine may suddenly accelerate as the motor speed increases. Similarly, when operating the work equipment, if the gear shift and accelerator controls are operated improperly while the motor is running at low RPM, the work equipment may suddenly activate as the motor speed increases.

[0008] With the above configuration, the motor suppression control restricts the increase in motor output, so even if the gear shift and accelerator are operated in an improper manner, sudden acceleration of the machine and sudden operation of the work equipment are suppressed, allowing the machine to start driving or working appropriately. The gear shifting device is operated after the motor speed has been moderately increased using the accelerator, which moderately mitigates the rate of increase in rotational power transmitted from the motor to the travel or work device by the power transmission mechanism. Conversely, if the motor speed is increased with the accelerator after the gear shifting device has been operated, power will be transmitted abruptly (directly) from the motor to the travel or work device, which may cause the machine to start suddenly or the work device to start abruptly. Therefore, by performing motor suppression control when the accelerator is operated after the gear shift is operated, sudden acceleration of the machine and abrupt operation of the work equipment are suppressed, allowing the machine to start driving or working appropriately.

[0009] Furthermore, the motor suppression control may be a control that restricts the increase in the motor rotation speed.

[0010] With this configuration, in motor suppression control, the increase in motor rotation speed can be restricted (suppressed), and the motor output can be easily and appropriately controlled, enabling the vehicle to start driving or working properly.

[0011] Furthermore, the motor suppression control may be a control that restricts the increase in the motor's torque.

[0012] With this configuration, in motor suppression control, the increase in motor torque can be restricted (suppressed), allowing for easy and appropriate regulation of the motor output, and enabling the vehicle to start driving or working properly.

[0013]

[0014]

[0015]

[0016] Furthermore, the first rotational speed may be 0 rotations.

[0017] This configuration suppresses a rapid increase in motor speed from a non-rotating state, thereby preventing sudden starts of the machine and abrupt operation of the work equipment.

[0018] Furthermore, the motor suppression control may also be a control that does not increase the motor rotation speed.

[0019] This configuration allows for easier and more precise regulation of motor output increases, thereby suppressing sudden starts of the machine and abrupt operation of work equipment, enabling proper movement or operation to commence.

[0020] Furthermore, the motor suppression control may also be a control that sets the upper limit of the motor rotation speed that can be increased to a predetermined idling speed greater than 0 rotations.

[0021] With such a configuration, the upper limit of the motor speed is regulated to the idling speed at which the traveling device and the working device hardly operate, suppressing the increase in the motor speed. Therefore, sudden acceleration of the machine body and sudden operation of the working device are suppressed, and traveling or work can be appropriately started.

[0022] In addition, since the motor speed increases moderately, the operator (worker / driver) can recognize that the motor is operating due to the motor sound. Therefore, the operator can be conscious of operating the shift operating tool and the accelerator operating tool in an appropriate procedure, and can appropriately start traveling or work.

[0023] Also, the motor suppression control may be a control for setting the motor speed to a predetermined second speed greater than the first speed when the shift operating tool is operated while the motor speed is The aforementioned below the first speed.

[0024] With such a configuration, since the motor speed is set to the second speed and the motor speed is increased in advance, even if the accelerator operating tool is operated, a rapid increase in the motor speed is suppressed. As a result, sudden acceleration of the machine body and sudden operation of the working device are suppressed, and traveling or work can be appropriately started.

[0025] In addition, since the motor speed increases moderately, the operator (operator / driver) can recognize that the motor is operating due to the motor sound. Therefore, the operator can be conscious of operating the shift operating tool and the accelerator operating tool in an appropriate procedure, and can appropriately start traveling or work.

[0026] Also, the motor suppression control may be a control for increasing the motor speed at a predetermined acceleration or less.

[0027] This configuration suppresses a rapid increase in motor output, resulting in a gradual increase. This prevents sudden starts of the machine and abrupt operation of the work equipment, allowing for proper movement or commencement of work.

[0028] Furthermore, the motor control unit may release the motor suppression control when the gear shifting device is returned to its original position.

[0029] When the gear shift lever is returned to the neutral position, for example, the running gear and working gear become inoperable. Therefore, even if the motor suppression control is released, the machine will not suddenly accelerate or the working gear will not suddenly activate. In this state, by operating the gear shift lever and accelerator lever in the appropriate procedure, the machine can start running or working properly.

[0030] Furthermore, the motor control unit may release the motor suppression control when the gear shifting device is returned to its original position and the motor rotation speed becomes 0 revolutions.

[0031] When the gear shift lever is returned to the neutral position, for example, and the motor speed becomes 0 revolutions per minute, the travel and work devices become inoperable. Therefore, even if the motor suppression control is released, the machine will not suddenly start or the work devices will not suddenly operate. In this state, by operating the gear shift lever and accelerator lever in the appropriate procedure, the machine can start traveling or working properly.

[0032] Furthermore, the system may further include a hydrostatic continuously variable transmission (CVT) for changing the speed of the rotational power transmitted from the motor to the travel device, and the gear shifting device may include an HST operating device for operating the angle of the swashplate of the hydrostatic continuously variable transmission.

[0033] With this configuration, even if the angle of the swashplate of the hydrostatic continuously variable transmission is not operated in the correct procedure, sudden acceleration of the machine is suppressed, and it can start moving properly.

[0034] Furthermore, the speed control device may include a PTO (Power Take-Off) device for controlling the speed of the rotational power transmitted from the motor to the work device.

[0035] With this configuration, even if the rotational power shifting operation is not performed in the proper procedure, sudden operation of the work device is suppressed, and work can be started properly. [Brief explanation of the drawing]

[0036] [Figure 1] This is a left side view of the tractor. [Figure 2] This is a left side view showing the arrangement of inverters and other components. [Figure 3] This is a diagram showing the power transmission flow. [Figure 4] This diagram illustrates the configuration of the control devices in the driver's unit. [Figure 5] This diagram illustrates a functional configuration for controlling a motor. [Figure 6] This figure illustrates the processing flow of motor suppression control in Embodiment 1. [Figure 7] This diagram illustrates the rotational speed transition, which is the change in motor rotational speed in response to the amount of accelerator lever operation. [Figure 8] This diagram illustrates the notification flow in Embodiment 2. [Modes for carrying out the invention]

[0037] Embodiments for carrying out the present invention will be described with reference to the drawings. In the following description, unless otherwise specified, the direction of arrow F in the figures is "forward", the direction of arrow B is "backward", the direction of arrow L is "left", and the direction of arrow R is "right". Also, the direction of arrow U in the figures is "up", and the direction of arrow D is "down".

[0038] [Overall configuration of the tractor] In the following, an electric tractor (hereinafter simply referred to as "tractor") will be described as an electric work vehicle according to this embodiment. As shown in Figure 1, the tractor is equipped with left and right front wheels 10, left and right rear wheels 11, and a cover member 12.

[0039] The tractor also includes a machine frame 2 and a driver's unit 3. The machine frame 2 is supported by the left and right front wheels 10 (corresponding to the "running gear") and the left and right rear wheels 11 (corresponding to the "running gear").

[0040] The cover member 12 is located at the front of the aircraft body. The control unit 3 is located behind the cover member 12. In other words, the cover member 12 is located in front of the control unit 3.

[0041] The driver's unit 3 includes a protective frame 30, a driver's seat 31, and a steering wheel 32. The operator (worker / driver) can sit in the driver's seat 31. This allows the operator to board the driver's unit 3. The left and right front wheels 10 are steered by operating the steering wheel 32. The operator can perform various driving operations in the driver's unit 3.

[0042] The tractor is equipped with a traction battery 4. The cover member 12 is configured to swing around an opening / closing axis Q that runs along the left-right direction of the machine body. This allows the cover member 12 to be opened and closed. When the cover member 12 is closed, the traction battery 4 is covered by the cover member 12.

[0043] As shown in Figure 2, the tractor is equipped with an inverter 14 and a motor M (electric motor). The traction battery 4 supplies power to the inverter 14. The inverter 14 converts the DC power from the traction battery 4 into AC power and supplies it to the motor M. The motor M is then driven by the AC power supplied from the inverter 14.

[0044] 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.

[0045] The hydraulic pump 15a is driven by rotational power from the motor M. 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 variable. Furthermore, the hydrostatic continuously variable transmission 15 is configured so that the gear ratio can be changed steplessly.

[0046] 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.

[0047] Furthermore, as shown in Figures 2 and 3, the tractor is equipped with a mid-PTO shaft 17 and a rear PTO shaft 18 (hereinafter, these may be collectively referred to simply as "PTO shafts"). The rotational power output from the motor M 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.

[0048] 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.

[0049] [Driving and operation] As shown in Figures 1 and 4, the driver's unit 3 is equipped with various operating devices for driving or operating. For example, the operating devices include a main gear lever 34, a sub-gear lever 35, an accelerator lever 37 (corresponding to the "accelerator operating device"), an HST pedal 38 (corresponding to the "gear shift operating device" and "HST operating device"), and a PTO lever 39 (corresponding to the "gear shift operating device" and "PTO operating device"). Although these operating devices are described as levers and pedals, they may be of any form.

[0050] The main gear lever 34 and the sub-gear lever 35 are located to the left of the driver's seat 31 and are used to set the vehicle speed for forward and reverse driving. The accelerator lever 37 is located to the right of the steering wheel 32 and is used to raise or lower the rotational speed of the motor M. The PTO lever 39 is located to the left of the driver's seat 31 and is used to change the rotational power of the PTO shaft.

[0051] The HST pedal 38 is located to the right and in front of the driver's seat 31 on the floor of the driver's compartment 3. The HST pedal 38 is operated with the right foot by the operator seated in the driver's seat 31 and is used to initiate forward and reverse movement and to adjust the vehicle speed. In this case, the vehicle speed is limited to the range of vehicle speed set by the main transmission lever 34 and the sub-transmission lever 35. The HST pedal 38 receives a shift operation of the rotational power driving the wheels (front wheels 10 and rear wheels 11), and when tilted forward from the neutral position, it changes the angle of the swash plate of the hydrostatic continuously variable transmission 15, causing the machine to move forward. Also, when the HST pedal 38 is tilted backward from the neutral position, it changes the angle of the swash plate of the hydrostatic continuously variable transmission 15, causing the machine to move backward. The amount the HST pedal 38 is tilted forward or backward allows the vehicle speed to be controlled.

[0052] When the machine is to move, with the motor M running, the main gear lever 34 and the sub-gear lever 35 are first operated to set the maximum vehicle speed for forward or reverse movement. Next, the accelerator lever 37 is operated to adjust the rotational speed of the motor M to a speed suitable for driving and work. Then, the HST pedal 38 is operated to start the machine from moving. By operating in this procedure, the hydrostatic continuously variable transmission 15 mitigates the sudden transmission of the rotational power of the motor M to the wheels (front wheels 10 and rear wheels 11), thereby preventing the machine from accelerating suddenly.

[0053] In this process, when adjusting the power of the PTO shaft, the accelerator lever 37 is operated to adjust the rotational speed of the motor M, and then the PTO lever 39 is operated to adjust the rotational power output to the PTO shaft to a level suitable for the work. By operating in this procedure, the hydrostatic continuously variable transmission 15 mitigates the sudden transmission of the rotational power of the motor M to the work device, thereby suppressing the sudden operation of the work device.

[0054] If the operator fails to notice that the motor M is operating and does not operate the control tools in the appropriate procedure described above, the machine may not be able to start moving properly, and the work may not be able to be performed properly. For example, if the accelerator lever 37 is operated after the HST pedal 38 is operated, the rotational power of the motor M will be transmitted abruptly (directly) to the wheels (front wheels 10 and rear wheels 11), and the machine may start moving suddenly without intention. Also, if the accelerator lever 37 is operated after the PTO lever 39 is operated, the rotational power of the motor M will be transmitted abruptly (directly) to the work device, and the work device may start moving suddenly without intention.

[0055] The following describes embodiments for suppressing such inappropriate driving and work.

[0056] [Embodiment 1] First, as Embodiment 1, a configuration that suppresses inappropriate driving and operation by controlling the output of motor M will be explained using Figures 5 to 7, with reference to Figures 3 and 4.

[0057] The tractor according to Embodiment 1 performs predetermined motor suppression control to prevent improper driving and work. The motor suppression control is controlled by the control unit 50. The control unit 50 is equipped with a processor such as a CPU or ECU and operates under the control of the processor.

[0058] The control unit 50 is connected to operating devices such as the main gear lever 34, sub-gear lever 35, accelerator lever 37, HST pedal 38, and PTO lever 39, and controls the motor M and the hydrostatic continuously variable transmission 15 / transmission 16 according to the operating state of these devices. As described above, the motor M drives the wheels (front wheels 10 and rear wheels 11) and the PTO shafts (mid-PTO shaft 17 and rear PTO shaft 18). An alert unit 26 may also be connected to the control unit 50, in which case the control unit 50 causes the alert unit 26 to provide predetermined alerts.

[0059] The control unit 50 includes an operation acquisition unit 52, a motor control unit 54, and, if a notification unit 26 is provided, a notification control unit 55.

[0060] The operation acquisition unit 52 acquires information regarding operations performed on operating devices such as the main transmission lever 34, sub-transmission lever 35, accelerator lever 37, HST pedal 38, and PTO lever 39. Specifically, the operation acquisition unit 52 acquires information such as the operating position of the operating device.

[0061] The motor control unit 54 controls the output of motor M, such as motor speed and torque, based on information about operations performed on the operating tool acquired by the operation acquisition unit 52. Furthermore, if the accelerator operating tool, HST pedal 38, and PTO lever 39 are operated in an improper manner, the motor control unit 54 executes a predetermined motor suppression control to restrict the increase in motor M's output. The notification control unit 55 causes the notification unit 26 to issue a predetermined notification, for example, an notification that motor suppression control is being executed.

[0062] In this configuration, when starting work driving with the motor M running, first the main transmission lever 34 and the sub-transmission lever 35 are operated. Next, the accelerator lever 37 (accelerator control device) is operated to adjust the motor speed of the motor M. The proper procedure is to operate the accelerator lever 37 (accelerator control device) first, and then operate the HST pedal 38 and the PTO lever 39 (transmission control device) to positions suitable for work driving.

[0063] The following description explains the process in which motor suppression control is performed when the operating device is not operated properly. Specifically, the HST pedal 38 and PTO lever 39 (gear shifting device) are operated to positions suitable for work driving without the accelerator lever 37 (accelerator operating device) being operated (Step #1 in Figure 6).

[0064] Next, the motor control unit 54 determines whether the motor speed is 0 revolutions (0 revolutions / minute rpm) (Step #2 in Figure 6). In other words, according to the proper procedure, the accelerator lever 37 (accelerator control device) is operated first, followed by the HST pedal 38 and PTO lever 39 (gear shift control device). However, it is checked whether at least one of the HST pedal 38 and PTO lever 39 (gear shift control device) has been operated while the accelerator lever 37 (accelerator control device) is not being operated. If the motor speed is 0 revolutions (Step #2 in Figure 6: Yes), it is further checked whether the accelerator lever 37 (accelerator control device) has been operated (Step #3 in Figure 6). This allows the motor control unit 54 to determine whether the accelerator lever 37 (accelerator control device) was operated (operated in an improper procedure) after the HST pedal 38 and PTO lever 39 (gear shift control device) were being operated, starting from a state where the motor speed is 0 revolutions.

[0065] If the accelerator lever 37 (accelerator control device) is operated after the HST pedal 38 and PTO lever 39 (gear shift control device) have been operated (Step #3 Yes in Figure 6), the motor control unit 54 restricts the increase in motor speed as a motor suppression control, so that the motor speed of motor M does not increase from 0 rpm (Step #4 in Figure 6).

[0066] Figure 7 illustrates the rotational speed transition, which is the change in motor rotational speed in response to the amount of operation of the accelerator lever 37. When the accelerator lever 37 (accelerator control device) is operated, and then the HST pedal 38 and PTO lever 39 (gear shift control device) are operated, and the controls are operated appropriately, the motor rotational speed changes according to the amount of operation of the accelerator lever 37, within an upper limit range corresponding to the amount of operation of the main gear shift lever 34 and the sub-gear shift lever 35, as shown in rotational speed transition LR0.

[0067] In contrast, when motor suppression control is performed, as shown in the rotational speed transition LC1, the motor rotational speed remains at 0 rpm and does not change even when the accelerator lever 37 is operated.

[0068] Thus, with the motor suppression control in this embodiment, even if the accelerator lever 37 is operated, the motor speed does not increase, the machine does not start, and the work equipment does not operate. As a result, sudden starts of the machine and sudden operation of the work equipment are suppressed, and the operator is encouraged to operate the control tools in the appropriate procedure. Then, by repeating the operation in the appropriate procedure, it is possible to start driving or working properly.

[0069] If a predetermined release condition is met while motor suppression control is being performed (step #5 in Figure 6), the motor control unit 54 terminates the motor suppression control (step #6 in Figure 6). The release condition is that the HST pedal 38 and PTO lever 39 are turned OFF (returned to the neutral position). Alternatively, the release condition may be that the HST pedal 38 and PTO lever 39 are turned OFF, and the accelerator lever 37 is returned to the 0 rpm position.

[0070] By setting a release condition that terminates the motor suppression control, the machine returns to a state where it can accept operations to move or operate the work equipment. Subsequently, by performing the operation in the appropriate procedure, it is possible to start moving or working properly.

[0071] Then, after the motor suppression control is completed, or if the motor rotation speed is not 0 revolutions (0 revolutions / minute rpm) (Step #2 No. in Figure 6), and if the accelerator lever 37 (accelerator control device) is not operated after the HST pedal 38 and PTO lever 39 (speed shift control device) have been operated (Step #3 No. in Figure 6), the motor control unit 54 controls the motor M in accordance with the operation of the accelerator lever 37, HST pedal 38, and PTO lever 39, etc., to start the work run (Step #7 in Figure 6).

[0072] [Another embodiment of Embodiment 1] (1) Motor suppression control may be performed not only when the motor M is at 0 revolutions, but also when the motor M is at or below a predetermined first revolution speed and the operating device is operated in a predetermined (inappropriate) procedure. Furthermore, motor suppression control may be performed when the accelerator lever 37 (accelerator operating device) is operated after the HST pedal 38 and PTO lever 39 (gear shift operating device) have been operated, without confirmation of whether the motor M is at or below a predetermined first revolution speed or at 0 revolutions.

[0073] As a result, motor suppression control is properly executed when necessary, preventing sudden starts of the machine and abrupt operation of work equipment, allowing for proper driving or work commencement.

[0074] (2) Motor suppression control is not limited to a configuration that prevents an increase in motor speed, but may also be a configuration that prevents an increase in the torque of motor M. Furthermore, motor suppression control is not limited to motor speed or motor M torque, but may also be output suppression control that restricts the increase in the output of motor M by any method.

[0075] This configuration allows for the appropriate regulation (suppression) of the increase in rotational power of the motor M transmitted to the wheels (front wheels 10 and rear wheels 11) and work equipment, depending on the situation. As a result, sudden starts of the machine and rapid operation of the work equipment are suppressed, allowing for proper driving or work commencement.

[0076] (3) The motor suppression control is not limited to a configuration that prevents the motor speed from increasing. Even when the accelerator lever 37 is operated, the motor speed may be controlled so that it does not rise above a predetermined idling speed greater than 0 rpm. In other words, as shown in the rotation speed transition LC2 in Figure 7, the motor control unit 54 controls the motor speed so that it does not rise above the idling speed even when the HST pedal 38 or PTO lever 39 (speed shifting device) is operated when the motor speed is 0 rpm or a small rotation (below a predetermined first rotation speed). The idling speed is the motor speed at which the machine does not start and the work equipment cannot perform work, or the motor speed at which the machine can only travel at an extremely low speed and the work equipment hardly operates. Specifically, the idling speed is 300 rpm or more and 900 rpm or more, for example, 600 rpm, which is slightly lower than the motor speed at which the machine actually starts to move.

[0077] As a result, even when the accelerator lever 37 is operated, the motor speed will not rise above the idling speed. Consequently, sudden starts of the machine and abrupt operation of the work equipment are suppressed, allowing for proper driving or work commencement. Furthermore, because the motor M is at idling speed, the operator can notice that the motor M is operating by the sound of its rotation. Therefore, the operator can recognize that the motor M is operating and consciously start the machine or operate the work equipment in the appropriate procedure. As a result, proper procedures are followed, sudden starts of the machine and abrupt operation of the work equipment are suppressed, and driving or work commencement is possible in the appropriate manner.

[0078] (4) The motor suppression control is not limited to a configuration that does not increase the motor speed, but may also be configured to control the motor speed to a predetermined speed that is within a range of motor speeds that do not cause the machine to start suddenly or the work equipment to operate rapidly when the accelerator lever 37 is not operated. For example, as motor suppression control, when the accelerator lever 37 is not operated, the motor speed may be set to a predetermined second speed that is greater than the first speed, and when the accelerator lever 37 is operated, the motor speed may increase from the second speed according to the amount of operation. The second speed is a motor speed at which the machine does not start and the work equipment cannot perform work, or a motor speed at which the machine can only travel at an extremely low speed and the work equipment hardly operates. Specifically, the second speed is 300 revolutions / min (rpm) or more and 900 revolutions / min (rpm), for example, 600 revolutions / min (600 rpm), which is slightly lower than the motor speed at which the machine actually starts to move. In other words, as shown in the rotational speed transition LC3 in Figure 7, when the motor rotational speed is 0 revolutions or a small rotation (below a predetermined first rotational speed), the motor control unit 54 increases the motor rotational speed to the second rotational speed regardless of the operating position of the accelerator lever 37 when the HST pedal 38 or PTO lever 39 (gear shifting device) is operated. Subsequently, when the accelerator lever 37 is operated, the motor rotational speed is changed from the second rotational speed in accordance with the operation of the accelerator lever 37.

[0079] As a result, the motor speed is pre-increased when the HST pedal 38 or PTO lever 39 (gear shifter) is operated, so a sudden increase in motor speed is suppressed even when the accelerator lever 37 (accelerator) is operated. As a result, sudden starts of the machine and sudden operation of the work equipment are suppressed, allowing for proper driving or work to begin. In addition, by maintaining the second rotational speed of the motor M, the operator can notice that the motor M is operating by the sound of the motor M rotating. Therefore, the operator can recognize that the motor M is operating and consciously start the machine or operate the work equipment in the appropriate procedure. As a result, sudden starts of the machine and sudden operation of the work equipment are suppressed, allowing for proper driving or work to begin.

[0080] (5) As motor suppression control, control may be performed to increase the motor speed at an acceleration below a predetermined level. In other words, if the accelerator lever 37 (accelerator) is operated after the HST pedal 38 or PTO lever 39 (gear shifter) is operated, as motor suppression control, the motor speed is controlled to increase gradually at an acceleration below a predetermined level. As a result, a rapid increase in motor speed is suppressed, preventing the machine from starting suddenly or the work equipment from operating suddenly, and allowing the machine to start driving or working appropriately.

[0081] (6) The notification unit 26 may be omitted. This allows for a simpler configuration of the tractor.

[0082] [Embodiment 2] Next, as Embodiment 2, a configuration that suppresses inappropriate driving and work by notifying when motor M is operating will be described with reference to Figures 3 and 4, and with reference to Figures 5, 7, and 8.

[0083] The tractor according to Embodiment 2 provides notification that the motor M is operating while it is running, in order to suppress improper driving and operation. The operator (worker / driver) can recognize that the motor M is operating through this notification and be mindful to drive the machine or operate the work equipment in the appropriate procedure. As a result, the operation is performed in the appropriate procedure, sudden acceleration of the machine and abrupt operation of the work equipment are suppressed, and driving or work can be started appropriately.

[0084] In the tractor according to Embodiment 2, when starting work driving with the motor M running, first the main transmission lever 34 and the sub-transmission lever 35 are operated. Next, the accelerator lever 37 (accelerator control device) is operated to adjust the motor speed of the motor M. In a proper procedure, after the accelerator lever 37 (accelerator control device) is operated, at least one of the HST pedal 38 and the PTO lever 39 (transmission control device) is operated to a position suitable for work driving.

[0085] The following description explains the control actions taken by the tractor when the operation is performed using an improper procedure. Specifically, the HST pedal 38 and PTO lever 39 (gear shifter) are operated to positions suitable for work driving without the accelerator lever 37 (accelerator control device) being operated (Step #1 in Figure 8).

[0086] Next, the motor control unit 54 determines whether the motor rotation speed is 0 revolutions (0 revolutions / minute rpm) (step #2 in Figure 8). In other words, according to the proper procedure, the accelerator lever 37 (accelerator control device) is operated first, followed by the HST pedal 38 and the PTO lever 39 (gear shift control device). However, it is confirmed whether at least one of the HST pedal 38 and the PTO lever 39 (gear shift control device) has not been operated while the accelerator lever 37 (accelerator control device) has not been operated.

[0087] If the motor rotation speed is 0 revolutions (Step #2 Yes in Figure 8), the notification control unit 55 causes the notification unit 26 to notify that the motor M is in operation (Step #3 in Figure 8).

[0088] Subsequently, the operator, upon recognizing that the motor M is operating, sets the HST pedal 38 and PTO lever 39 (gear shifter) to the OFF position (neutral position), operates the accelerator lever 37 (accelerator), and then operates at least one of the HST pedal 38 and PTO lever 39 (gear shifter) (Step #4 in Figure 8). This initiates the operation of the machine in response to subsequent operations on the controls (Step #5 in Figure 8). Proper operation is also performed when the motor speed is not 0 revolutions (0 revolutions / minute rpm) (when the motor speed is increasing) (Step #2 No in Figure 8).

[0089] This configuration allows the operator (worker / driver) to recognize that the motor M is operating and to consciously move the machine or operate the work equipment in the appropriate procedure. As a result, the operation is performed in the appropriate procedure, preventing sudden starts of the machine or abrupt operation of the work equipment, and enabling the machine to move or start work appropriately.

[0090] [Another embodiment of Embodiment 2] (1) After at least one of the HST pedal 38 and the PTO lever 39 (speed shifting device) is operated, a notification that the motor M is operating may be given not only when the rotation speed is 0, but when the rotation speed of the motor M is less than or equal to a predetermined first rotation speed.

[0091] As a result, the operator is appropriately notified when they should be aware that motor M is operating, allowing them to accurately recognize that motor M is running. Consequently, by operating the machine using the appropriate procedures, sudden starts of the machine and abrupt activation of the work equipment are suppressed, enabling the machine to start moving or working appropriately.

[0092] (2) Not limited to a configuration in which notification is given when the motor speed is 0 revolutions (1st revolution speed or less) when at least one of the HST pedal 38 and the PTO lever 39 is operated, the notification control unit 55 may cause the notification unit 26 to give a notification that the motor M is in operation while the motor speed is 0 revolutions or 1st revolution speed or less after the motor M is started. In this case, if the accelerator lever 37 (accelerator operating device) is operated, the notification control unit 55 may terminate the notification.

[0093] This more accurately prevents at least one of the HST pedal 38 and PTO lever 39 (gear shifter) from being operated when the accelerator lever 37 (accelerator control device) is not being operated. As a result, by operating the machine in the appropriate procedure, sudden starts of the machine and abrupt operation of the work equipment are suppressed, and the machine can start driving or working properly.

[0094] (3) In conjunction with or separately from each of the above embodiments, the tractor may maintain the motor speed of the motor M at or above an idling speed, which is a predetermined speed greater than 0 rpm, when the motor M is in operation (LC4 in Figure 7). The motor sound of the motor M operating at the idling speed allows the operator to recognize that the motor M is in operation. As a result, by operating the machine in an appropriate manner, sudden starts of the machine and sudden operation of the work equipment can be suppressed, and the machine can start driving or working appropriately.

[0095] (4) When the motor suppression control in Embodiment 1 is executed, the notification control unit 55 may cause the notification unit 26 to notify at least one of the following: that motor suppression control is being performed, and that the motor M is operating. This allows the operator to recognize with greater accuracy that the motor M is operating. As a result, by operating in the appropriate procedure, the sudden acceleration of the machine and the sudden operation of the work equipment are suppressed, and the machine can start moving or working appropriately.

[0096] [Another embodiment] (1) In each of the above embodiments, the gear shifting device is not limited to the HST pedal 38 and the PTO lever 39, but may be any device for shifting the rotational power, or any combination thereof. Also, the accelerator device is not limited to the accelerator lever 37, but may be any device for raising or lowering the motor speed of the motor M, or any combination thereof. When at least one of the gear shifting devices and at least one of the accelerator devices are operated in an improper manner, at least one of motor suppression control or a predetermined notification is performed.

[0097] This allows for motor suppression control or predetermined notification, depending on the tractor's configuration, enabling it to start driving or working appropriately.

[0098] (2) In each of the above embodiments, the notification unit 26 may be any configuration that provides notification to the operator. For example, the notification unit 26 may be a speaker or voice alarm generator that can emit voice or warning sounds, an LED, lamp or warning light that can provide notification by lighting or flashing patterns, a monitor or information terminal that can display characters or images, or a combination thereof. This allows for notification that is easy for the operator to understand, depending on the situation.

[0099] (3) In each of the above implementations, the running gear may be crawlers rather than wheels.

[0100] (4) In each of the above embodiments, the control unit 50 is not limited to being composed of the functional blocks described above, but may be composed of any functional blocks. For example, each functional block of the control unit 50 may be further subdivided, or conversely, some or all of each functional block may be combined. Also, the functions of the control unit 50 are not limited to the above functional blocks, but may be realized by any functional block executing. Also, some or all of the functions of the control unit 50 may be composed of software. The program related to the software is stored in any storage device and executed by a processor such as a CPU in the control unit 50, or by a separately provided processor. [Industrial applicability]

[0101] This invention can be applied to electric agricultural vehicles such as tractors, harvesters, and rice transplanters, as well as various electric work vehicles that perform various tasks while being driven by electric power. [Explanation of symbols]

[0102] 10 Front wheels (running gear) 11. Rear wheels (running gear) 15. Hydrostatic continuously variable transmission 37. Accelerator lever (accelerator control device) 38 HST pedals (HST control device / gear shift control device) 39. PTO lever (PTO operating device / speed control device) 54 Motor control unit M Motor

Claims

1. A motor that drives at least one of the traveling device and the working device, A speed control device for changing the speed of the rotational power that drives the aforementioned travel device or the aforementioned work device, An accelerator operating device for raising or lowering the motor speed of the aforementioned motor, The system includes a motor control unit that controls the motor speed in response to operation on the accelerator operating device, The motor control unit performs motor suppression control to restrict the output of the motor when the gear shifting device is operated to the travel position before the accelerator device is operated, and then the accelerator device is operated while the motor rotation speed is below a predetermined first rotation speed.

2. The electric work vehicle according to claim 1, wherein the motor suppression control is a control that restricts the increase in the motor rotation speed.

3. The electric work vehicle according to claim 1, wherein the motor suppression control is a control that restricts the increase in the torque of the motor.

4. The electric work vehicle according to claim 1, wherein the motor suppression control is a control that does not increase the motor rotation speed.

5. The electric work vehicle according to claim 1, wherein the motor suppression control is a control that sets the upper limit of the motor rotation speed that can be increased to a predetermined idling rotation speed greater than 0 rotations.

6. The electric work vehicle according to claim 1, wherein the motor suppression control is a control that sets the motor rotation speed to a predetermined second rotation speed greater than the first rotation speed when the gear shifting device is operated while the motor rotation speed is less than or equal to the first rotation speed.

7. The electric work vehicle according to claim 1, wherein the motor suppression control is a control that increases the motor rotation speed at or below a predetermined acceleration.

8. The motor control unit releases the motor suppression control when the gear shifting device is returned, as described in claim 1.

9. The electric work vehicle according to claim 1, wherein the motor control unit releases the motor suppression control when the gear shifting device is returned and the motor rotation speed becomes 0 revolutions.

10. The system further comprises a hydrostatic continuously variable transmission for changing the speed of the rotational power transmitted from the motor to the travel device, The electric work vehicle according to claim 1, wherein the gear shifting device includes an HST operating device for operating the angle of the swashplate of the hydrostatic continuously variable transmission.

11. The electric work vehicle according to claim 1, wherein the gear shifting device includes a PTO operating device for shifting the rotational power transmitted from the motor to the work device.

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