JP7825504B2 - electric work vehicle - Google Patents

Description

The present invention relates to an electric work vehicle whose traveling gear is driven by a motor.

As shown in Patent Document 1, an electric tractor (electric work vehicle) uses a motor to drive both the travel device and the work device. Electric work vehicles such as electric tractors are equipped with various operating devices, and the motor and other components are controlled based on the operation of the various operating devices to drive and work.

JP 2013-150560 A

However, the motor can be in standby mode with a rotation speed of 0 rpm, and if the wrong procedure is performed when the motor is at 0 rpm, the machine may suddenly accelerate and be unable to start driving or working properly.

The purpose of this invention is to enable proper start of travel or operation even when the motor rotation speed is 0 rpm or at very low rotation speed.

In order to achieve the above object, an electric work vehicle according to one embodiment of the present invention comprises a motor that drives at least one of the travelling device and the working device, a speed change device that changes the speed of the rotational power that drives the travelling device or the working device, an accelerator operation device that increases or decreases the motor rotation speed of the motor, and a motor control unit that controls the motor rotation speed in response to operation of the accelerator operation device; if, while the motor is running and the vehicle is stopped, operation of the accelerator operation device after operation of the speed change device is detected, the operation is detected as an inappropriate operation that would result in a sudden start of the vehicle, and motor suppression control is carried out to suppress an increase in motor output.

When starting the machine, if a driver mistakenly believes the motor is stopped even though it is actually running at low RPM and operates the gearshift and accelerator controls in an inappropriate manner, the motor's rotation speed may increase, causing the machine to suddenly and unintentionally start moving. Furthermore, when operating a work device, if a driver mistakenly believes the motor is stopped even though it is running at low RPM and operates the gearshift and accelerator controls in an inappropriate manner, the motor's rotation speed may increase, causing the work device to suddenly and unintentionally start moving.

With the above configuration, a predetermined notification is issued while the motor is running, allowing the operator (work vehicle driver) to recognize that the motor is running. This prevents the operator from mistakenly thinking that the motor is stopped when it is actually running at low speed, and helps the operator to be aware of operating the gear shift and accelerator controls in the appropriate order. As a result, the vehicle can be driven or work can be started appropriately.

Furthermore, the predetermined notification for avoiding the inappropriate operation may be given when, after the speed change operating device is operated, the motor rotation speed is 0 rotations or a predetermined first rotation speed or less.

By operating the speed change device after using the accelerator device to increase the motor rotation speed appropriately, the rate at which the rotational power increases is moderated by the power transmission mechanism that transmits power from the motor to the traveling device or working device.

Therefore, by issuing a notification when the motor rotation speed is 0 or almost zero after the gearshift operating device is operated, the operator can recognize that the motor M is running. As a result, the operator can be aware of the need to operate the gearshift operating device and accelerator operating device in the appropriate procedure, allowing them to start driving or working appropriately.

Furthermore, when the speed change operating device is operated while the speed is below the first speed, the motor control unit may set the motor speed to a second speed or less that is greater than the first speed and at which a specified vehicle will not take off , and the notification may be made by the sound of the motor rotating.

With this configuration, the motor rotation speed is set to the second rotation speed, and the motor generates a motor sound. The motor sound then lets the operator know that the motor is running. This allows the operator to be aware of the proper procedure for operating the gear shift and accelerator controls, allowing them to start driving or working appropriately.

Furthermore, the motor control unit may control the motor rotation speed so that it does not exceed an idling rotation speed, which is a predetermined rotation speed greater than 0 rotations, while the motor is operating, and the notification may be made by the sound of the motor rotating.

With this configuration, the motor speed is set below the idling speed at which the travel and work equipment are barely operating, causing the motor to emit a motor noise. The motor noise then lets the operator know that the motor is running. This allows the operator to be aware of the proper procedure for operating the gear change and accelerator controls, allowing them to start travel or work appropriately.

The device may also be equipped with a notification unit that issues the notification.

This configuration allows the operator to recognize that the motor is running. This allows the operator to be aware of the proper procedure for operating the gear shift and accelerator controls, allowing them to start driving or working appropriately.

Furthermore, the notification unit may be a speaker that emits a warning sound, and the notification may be made by the warning sound.

This configuration allows the operator to hear the warning sound to let them know that the motor is running. This helps the operator to be aware of the proper procedures for operating the gear shift and accelerator controls, allowing them to start driving or working appropriately.

Alternatively, the notification unit may be a warning light, and the notification may be made by turning on or flashing the warning light.

With this configuration, the operator can recognize that the motor is running by the warning light being lit or flashing. This allows the operator to be aware of the need to operate the gear shift and accelerator controls in the appropriate order, allowing them to start driving or working appropriately.

The vehicle may further include a hydrostatic continuously variable transmission that changes the speed of the rotational power transmitted from the motor to the travel device, and the speed change operating device may include an HST operating device that operates the angle of the swash plate of the hydrostatic continuously variable transmission.

This configuration allows the operator to recognize that the motor is running even if the HST operating device, which controls the angle of the swash plate of the hydrostatic continuously variable transmission, is not operated in the proper procedure. This allows the operator to be aware of the need to operate the transmission operating device in the proper procedure, allowing the vehicle to begin traveling appropriately.

The speed change operating device may also include a PTO operating device that changes the speed of the rotational power transmitted from the motor to the working device.

This configuration allows the operator to recognize that the motor is running even if the PTO operating device, which changes the rotational power, is not operated in the proper procedure. This allows the operator to be aware of the need to operate the operating device in the proper procedure, allowing them to start work appropriately.

FIG. 2 is a left side view of the tractor. FIG. 2 is a left side view showing the arrangement of an inverter and the like. FIG. 2 is a diagram illustrating a flow of power transmission. 3A and 3B are diagrams illustrating the configuration of an operating tool in a driving section. FIG. 2 is a diagram illustrating a functional configuration for controlling a motor. FIG. 4 is a diagram illustrating a processing flow of motor suppression control in the first embodiment. 10 is a diagram illustrating an example of a rotation speed transition, which is a change in the motor rotation speed relative to the operation amount of the accelerator lever. FIG. FIG. 10 is a diagram illustrating a flow of notification in the second embodiment.

The following description will explain the embodiments of the present invention with reference to the drawings. In the following description, unless otherwise specified, the direction of arrow F in the drawings will be referred to as "front," the direction of arrow B as "rear," the direction of arrow L as "left," and the direction of arrow R as "right." Furthermore, the direction of arrow U in the drawings will be referred to as "up," and the direction of arrow D as "down."

[Overall configuration of the tractor]
The following describes an electric tractor (hereinafter simply referred to as a "tractor") as an electric work vehicle according to this embodiment. As shown in Figure 1, the tractor has left and right front wheels 10, left and right rear wheels 11, and a cover member 12.

The tractor also includes a machine frame 2 and a driving section 3. The machine frame 2 is supported by left and right front wheels 10 (corresponding to the "running gear") and left and right rear wheels 11 (corresponding to the "running gear").

The cover member 12 is located at the front of the aircraft. The driver's unit 3 is located behind the cover member 12. In other words, the cover member 12 is located in front of the driver's unit 3.

The driver's unit 3 has 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, allowing 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 using the driver's unit 3.

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

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 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.

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.

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 speed of the rotational power is changed between the hydraulic pump 15a and the hydraulic motor 15b. The hydrostatic continuously variable transmission 15 is also configured so that the gear ratio can be changed continuously.

The rotational power output from the hydraulic motor 15b is transmitted to the transmission 16. The rotational power transmitted to the transmission 16 is changed in speed by the gear-type speed change mechanism of the transmission 16 and distributed to the left and right front wheels 10 and the left and right rear wheels 11. This drives the left and right front wheels 10 and the left and right rear wheels 11.

As shown in Figures 2 and 3, the tractor also has 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.

If a work device is connected to the mid-PTO shaft 17 or rear PTO shaft 18, the work device will be driven by the rotational power of the mid-PTO shaft 17 or rear PTO shaft 18. For example, as shown in Figure 2, in this embodiment, a brush cutter 19 is connected to the mid-PTO shaft 17. The brush cutter 19 is driven by the rotational power of the mid-PTO shaft 17.

[Travel and work operations]
As shown in Figures 1 and 4, the driving section 3 is provided with various operating tools for driving or working. For example, the operating tools include a main shift lever 34, an auxiliary shift lever 35, an accelerator lever 37 (corresponding to an "accelerator operating tool"), an HST pedal 38 (corresponding to a "speed change operating tool" and an "HST operating tool"), and a PTO lever 39 (corresponding to a "speed change operating tool" and an "PTO operating tool"). Note that although these operating tools are described as levers and pedals, they may each be operating tools in any form.

The main speed change lever 34 and sub-speed change lever 35 are located to the left of the driver's seat 31 and are used to set the vehicle speed in forward and reverse. The accelerator lever 37 is located to the right of the steering wheel 32 and is used to increase or decrease the rotation 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.

The HST pedal 38 is located on the floor of the driver's section 3, to the right of and in front of the driver's seat 31. 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 travel and to adjust the vehicle speed. In this case, the vehicle speed is limited to the range of vehicle speeds set by the main shift lever 34 and the auxiliary shift lever 35. The HST pedal 38 receives control over the rotational power that drives the wheels (front wheels 10 and rear wheels 11). When the HST pedal 38 is tilted forward from the neutral position, it changes the angle of the swash plate of the hydrostatic continuously variable transmission 15, moving the vehicle forward. 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, moving the vehicle backward. The HST pedal 38 can control the vehicle speed by the amount it is tilted forward or backward.

When the vehicle is to be driven, the main speed change lever 34 and the sub-speed change lever 35 are first operated with the motor M running to set the maximum vehicle speed for forward or reverse. Next, the accelerator lever 37 is operated to adjust the motor M's rotation speed to a speed suitable for driving and work. Then, the HST pedal 38 is operated to start the vehicle moving. By operating in this order, the hydrostatic continuously variable transmission 15 reduces the sudden transmission of the motor M's rotational power to the wheels (front wheels 10 and rear wheels 11), preventing the vehicle from suddenly starting.

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 suit the work. By operating in this order, the hydrostatic continuously variable transmission 15 reduces the sudden transmission of the rotational power of the motor M to the work device, preventing the work device from operating suddenly.

If the operator does not realize that motor M is running and does not operate the operating tools in the appropriate procedure as described above, the vehicle may not start moving properly, and work may not be carried out properly. For example, if the accelerator lever 37 is operated after the HST pedal 38 is operated, the rotational power of motor M may be transmitted abruptly (directly) to the wheels (front wheels 10 and rear wheels 11), which could result in the vehicle suddenly and unintentionally taking off. Furthermore, if the accelerator lever 37 is operated after the PTO lever 39 is operated, the rotational power of motor M may be transmitted abruptly (directly) to the working device, which could result in the working device suddenly and unintentionally starting up.

Below, we will explain an embodiment that prevents such inappropriate driving and work.

[Embodiment 1]
First, as a first embodiment, a configuration for suppressing inappropriate traveling and working by controlling the output of the motor M will be described with reference to FIGS. 3 and 4 and with reference to FIGS. 5 to 7. FIG.

The tractor according to embodiment 1 performs predetermined motor suppression control to prevent inappropriate driving and operation. 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.

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

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

The operation acquisition unit 52 acquires information regarding operations performed on operating devices such as the main shift lever 34, sub-shift 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 devices.

The motor control unit 54 controls the output of the motor M, such as the motor rotation speed and torque of the motor M, based on information regarding operations performed on the operating device acquired by the operation acquisition unit 52. Furthermore, if the accelerator operating device, HST pedal 38, or PTO lever 39 is operated in an inappropriate manner, the motor control unit 54 executes (implements) predetermined motor suppression control to restrict an increase in the output of the motor M. The notification control unit 55 causes the notification unit 26 to issue a predetermined notification, for example, to notify that motor suppression control is being executed.

In this configuration, when starting work travel with motor M running, first the main shift lever 34 and sub-shift lever 35 are operated. Next, the accelerator lever 37 (accelerator operating device) is operated to adjust the motor rotation speed of motor M. The appropriate procedure is to operate the accelerator lever 37 (accelerator operating device), and then operate the HST pedal 38 and PTO lever 39 (speed change operating device) to positions appropriate for work travel.

The following explanation describes the process for performing motor suppression control when the operating devices are not operated appropriately. That is, the accelerator lever 37 (accelerator operating device) is not operated, and the HST pedal 38 and PTO lever 39 (gear change operating device) are operated to positions appropriate for work driving (step #1 in Figure 6).

Next, the motor control unit 54 determines whether the motor rotation speed is 0 (0 revolutions per minute) (Step #2 in Figure 6). In other words, according to the appropriate procedure, the accelerator lever 37 (accelerator operation device) is operated, followed by the HST pedal 38 and PTO lever 39 (speed change operation device). However, when the accelerator lever 37 (accelerator operation device) is not operated, it is checked whether at least one of the HST pedal 38 and the PTO lever 39 (speed change operation device) is being operated. If the motor rotation speed is 0 (Step #2 in Figure 6: Yes), it is further checked whether the accelerator lever 37 (accelerator operation device) has been operated (Step #3 in Figure 6). This allows the motor control unit 54 to check whether the accelerator lever 37 (accelerator operation device) has been operated (inappropriately) after the HST pedal 38 and the PTO lever 39 (speed change operation device) have been operated from a state where the motor rotation speed was 0.

If the accelerator lever 37 (accelerator operation device) is operated after the HST pedal 38 and PTO lever 39 (gear change operation device) are operated (step #3 in Figure 6: Yes), the motor control unit 54 performs motor suppression control to restrict the increase in motor rotation speed of motor M so that the motor rotation speed does not increase from 0 rotations (step #4 in Figure 6).

Figure 7 is a diagram illustrating the rotation speed transition, which is the change in motor rotation speed in response to the amount of operation of the accelerator lever 37. When the accelerator lever 37 (accelerator operating device) is operated, followed by operation of the HST pedal 38 and PTO lever 39 (gear change operating device), and the operating devices are operated appropriately, the motor rotation speed changes in response to the amount of operation of the accelerator lever 37, within an upper limit range corresponding to the amount of operation of the main shift lever 34 and sub-shift lever 35, as shown in rotation speed transition LR0.

In contrast, when motor suppression control is being executed, as shown in rotation speed transition LC1, the motor rotation speed remains at 0 rotations and does not change even when the accelerator lever 37 is operated.

As such, with the motor suppression control of this embodiment, even if the accelerator lever 37 is operated, the motor rotation speed does not increase, the machine does not start moving, 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 user is encouraged to operate the operating tools in the appropriate procedure. Then, by repeating the operation in the appropriate procedure, travel or work can be started appropriately.

If a predetermined release condition is met while the motor suppression control is being executed (step #5 in FIG. 6), the motor control unit 54 terminates the motor suppression control (step #6 in FIG. 6). The release condition is that the HST pedal 38 and the PTO lever 39 are turned OFF (returned to the neutral position). Note that the release condition may also be that the HST pedal 38 and the PTO lever 39 are turned OFF and the accelerator lever 37 is returned to the 0 rotation position.

By setting a release condition that terminates motor suppression control, the machine returns to a state where it can accept operations to run the machine or operate the work equipment, and then by performing operations in the appropriate procedure, it can start running or working appropriately.

Then, after the motor suppression control is terminated, or if the motor rotation speed is not 0 (0 revolutions per minute (rpm)) (Step #2 in Figure 6: No), or if the accelerator lever 37 (accelerator operating device) is not operated after the HST pedal 38 and PTO lever 39 (gear change operating device) are operated (Step #3 in Figure 6: No), the motor control unit 54 controls the motor M in response to the operation of the accelerator lever 37, HST pedal 38, PTO lever 39, etc., to start work driving (Step #7 in Figure 6).

[Alternative to Embodiment 1] (1) Motor suppression control may be performed not only when the rotation speed of motor M is equal to or less than a predetermined first rotation speed, but also when an operating tool is operated in a predetermined (inappropriate) procedure. Furthermore, motor suppression control may be performed when the accelerator lever 37 (accelerator operating tool) is operated after the HST pedal 38 and PTO lever 39 (gear change operating tool) are operated, without checking whether the rotation speed of motor M is equal to or less than the predetermined first rotation speed or equal to 0 rotations.

This allows motor suppression control to be executed appropriately when necessary, preventing sudden acceleration of the machine or sudden operation of the work equipment, allowing for appropriate start of travel or work.

(2) The motor suppression control is not limited to a configuration that does not increase the motor rotation speed, but may also be a configuration that does not increase the torque of the motor M. Furthermore, the motor suppression control is not limited to a configuration that does not increase the motor rotation speed or the torque of the motor M, but may also be an output restriction control that restricts an increase in the output of the motor M using any method.

This configuration makes it possible to appropriately regulate (suppress) the increase in rotational power of the motor M transmitted to the wheels (front wheels 10 and rear wheels 11) and the work equipment depending on the situation. As a result, sudden acceleration of the vehicle and sudden operation of the work equipment are suppressed, allowing for appropriate start of travel or work.

(3) Motor suppression control is not limited to a configuration that prevents the motor rotation speed from increasing. It may also be configured so that the motor rotation speed does not increase above a predetermined idling rotation speed greater than 0, even when the accelerator lever 37 is operated. In other words, as shown by rotation speed transition LC2 in FIG. 7 , when the motor rotation speed is 0 or a small number of rotations (below a predetermined first rotation speed), the motor control unit 54 controls the motor rotation speed so that it does not increase above the idling rotation speed, even when the HST pedal 38 or PTO lever 39 (speed change device) is operated. The idling rotation speed is a motor rotation speed at which the machine cannot start moving and the implement cannot perform work, or a motor rotation speed at which the machine travels only at an extremely low speed and the implement barely operates. Specifically, the idling rotation speed is between 300 and 900 revolutions per minute (rpm), for example, 600 revolutions per minute (600 rpm), which is slightly lower than the motor rotation speed at which the machine actually begins to travel.

This prevents the motor rotation speed from rising above the idling rotation speed even when the accelerator lever 37 is operated. As a result, sudden acceleration of the machine and sudden operation of the work equipment are suppressed, allowing the machine to start traveling or work appropriately. Furthermore, by having motor M at idling rotation speed, the operator can hear the sound of motor M rotating and become aware that motor M is operating. This allows the operator to recognize that motor M is operating and to be mindful of following the appropriate procedure when starting the machine or operating the work equipment. As a result, operations are performed according to the appropriate procedure, preventing sudden acceleration of the machine and sudden operation of the work equipment, allowing the machine to start traveling or work appropriately.

(4) Motor suppression control is not limited to a configuration that does not increase the motor rotation speed, and may be configured to control the motor rotation speed to a predetermined rotation speed within a range that does not cause the vehicle to suddenly accelerate or the working device to suddenly operate when the accelerator lever 37 is not operated. For example, as motor suppression control, when the accelerator lever 37 is not operated, the motor rotation speed may be set to a predetermined second rotation speed that is greater than the first rotation speed, and when the accelerator lever 37 is operated, the motor rotation speed may be increased from the second rotation speed depending on the amount of operation. The second rotation speed is a motor rotation speed that does not cause the vehicle to accelerate or the working device to perform work, or a motor rotation speed that causes the vehicle to travel only at an extremely low speed and barely operates the working device. Specifically, the second rotation speed is between 300 and 900 revolutions per minute (rpm), for example, 600 rotations per minute (600 rpm), which is slightly lower than the motor rotation speed at which the vehicle actually begins to travel. In other words, as shown in rotation speed transition LC3 in Figure 7, when the HST pedal 38 or PTO lever 39 (speed change device) is operated while the motor rotation speed is 0 rotations or a small number of rotations (below a predetermined first rotation speed), the motor control unit 54 increases the motor rotation speed to the second rotation speed regardless of the operating position of the accelerator lever 37. Thereafter, when the accelerator lever 37 is operated, the motor rotation speed is changed from the second rotation speed in accordance with the operation of the accelerator lever 37.

As a result, the motor rotation speed is increased beforehand when the HST pedal 38 or PTO lever 39 (speed change operating device) is operated, preventing a sudden increase in motor rotation speed even when the accelerator lever 37 (accelerator operating device) is operated. As a result, sudden acceleration of the machine and sudden operation of the work equipment are prevented, allowing for appropriate start of travel or work. Furthermore, by maintaining the second rotation speed of motor M, the operator can be made aware that motor M is operating by the sound of motor M rotating. This allows the operator to recognize that motor M is operating and to be mindful of following the appropriate procedure when starting the machine or operating the work equipment. As a result, sudden acceleration of the machine and sudden operation of the work equipment are prevented, allowing for appropriate start of travel or work.

(5) Motor suppression control may be performed to increase the motor rotation speed at or below a predetermined acceleration. In other words, when the accelerator lever 37 (accelerator operation device) is operated after the HST pedal 38 or PTO lever 39 (speed change operation device) is operated, motor suppression control is performed to control the motor rotation speed to increase gradually at or below a predetermined acceleration. As a result, a sudden increase in motor rotation speed is suppressed, preventing the machine from suddenly starting or the work device from suddenly operating, allowing the machine to start traveling or work appropriately.

(6) The notification unit 26 may not be provided. This allows the tractor to be configured with a simpler structure.

[Embodiment 2]
Next, as a second embodiment, a configuration for suppressing inappropriate driving and work by notifying the user when the motor M is operating will be described using FIGS. 5, 7, and 8 with reference to FIGS. 3 and 4.

In order to prevent inappropriate driving and work, the tractor according to the second embodiment issues a notification that motor M is operating while motor M is operating. This notification lets the operator (worker/driver) know that motor M is operating, and helps them to be mindful of following the appropriate procedures when driving the machine or operating the work equipment. As a result, operations are performed according to the appropriate procedures, preventing sudden acceleration of the machine or sudden operation of the work equipment, and allowing driving or work to begin appropriately.

When the tractor according to embodiment 2 starts to travel for work with the motor M running, the main speed change lever 34 and the sub-speed change lever 35 are first operated. Next, the accelerator lever 37 (accelerator operating device) is operated to adjust the motor rotation speed of the motor M. The appropriate procedure is to operate the accelerator lever 37 (accelerator operating device), and then operate at least one of the HST pedal 38 and the PTO lever 39 (speed change operating device) to a position appropriate for travel for work.

The following explanation describes the control that the tractor performs when an improper operation is performed. That is, the accelerator lever 37 (accelerator operating device) is not operated, and the HST pedal 38 and PTO lever 39 (gear change operating device) are operated to positions appropriate for work travel (step #1 in Figure 8).

Next, the motor control unit 54 determines whether the motor rotation speed is 0 rotations (0 revolutions per minute (rpm)) (step #2 in Figure 8). In other words, according to the appropriate procedure, the accelerator lever 37 (accelerator operation device) is operated, followed by the HST pedal 38 and PTO lever 39 (gear change operation device). However, when the accelerator lever 37 (accelerator operation device) is not operated, it is confirmed whether at least one of the HST pedal 38 and the PTO lever 39 (gear change operation device) is not operated.

If the motor rotation speed is 0 (step #2 in Figure 8, Yes), the notification control unit 55 causes the notification unit 26 to issue a notification that the motor M is operating (step #3 in Figure 8).

Then, the operator, recognizing that motor M is running, turns HST pedal 38 and PTO lever 39 (speed change controls) to the OFF position (neutral position), operates accelerator lever 37 (accelerator control), and then operates at least one of HST pedal 38 and PTO lever 39 (speed change controls) (step #4 in Figure 8). This then causes work travel to begin in response to the operation of the controls (step #5 in Figure 8). Note that appropriate work travel also occurs when the motor rotation speed is not 0 rotations (0 revolutions per minute (rpm)) (the motor rotation speed is increasing) (step #2 No in Figure 8).

This configuration allows the operator (worker/driver) to recognize that motor M is operating and to be aware of the need to operate the machine or work equipment in the appropriate procedure. As a result, operations are performed in the appropriate procedure, preventing sudden acceleration of the machine or sudden operation of the work equipment, allowing for appropriate start of operation or travel.

[Another embodiment of embodiment 2]
(1) After at least one of the HST pedal 38 and the PTO lever 39 (gear change operating device) is operated, a notification that the motor M is operating may be made when the rotation speed of the motor M is equal to or lower than a predetermined first rotation speed, not just when the rotation speed is 0 rotations.

This ensures that the operator is properly notified when it is necessary to be aware that the motor M is operating, allowing the operator to accurately recognize that the motor M is operating. As a result, by the operator following the appropriate procedures, sudden acceleration of the machine and sudden operation of the work equipment can be prevented, allowing the operator to start traveling or work appropriately.

(2) The notification is not limited to a configuration in which a notification is made when the motor rotation speed is 0 rotations (less than the first rotation speed) when at least one of the HST pedal 38 and the PTO lever 39 is operated. After the motor M is started, while the motor rotation speed is 0 rotations or less than the first rotation speed, the notification control unit 55 may cause the notification unit 26 to issue a notification that the motor M is operating. In this case, when the accelerator lever 37 (accelerator operating device) is operated, the notification control unit 55 may terminate the notification.

This more accurately prevents the HST pedal 38 and/or the PTO lever 39 (gear change operating device) from being operated when the accelerator lever 37 (accelerator operating device) is not being operated. As a result, by having the operator operate the device in the appropriate procedure, sudden acceleration of the machine and sudden operation of the work equipment are prevented, allowing for appropriate travel or work start.

(3) In addition to or separately from the above embodiments, when the motor M of the tractor is operating, the motor speed may be maintained at or above an idling speed, which is a predetermined speed greater than 0 rpm. The motor sound of the motor M operating at the idling speed allows the operator to recognize that the motor M is operating. As a result, by the operator performing operations in the appropriate procedure, sudden acceleration of the machine and sudden operation of the work equipment can be suppressed, allowing the operator to start traveling or work appropriately.

(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 the motor suppression control is being executed, and that the motor M is operating. This allows the operator to more accurately recognize that the motor M is operating. As a result, by the operator performing operations in the appropriate procedure, sudden acceleration of the machine and sudden operation of the work device are suppressed, allowing for appropriate start of travel or work.

[Another embodiment]
(1) In each of the above embodiments, the gearshift operating devices are not limited to the HST pedal 38 and the PTO lever 39, but may be any operating devices for operating a gearshift of rotational power, or any combination thereof. Furthermore, the accelerator operating device is not limited to the accelerator lever 37, but may be any operating device for increasing or decreasing the motor rotation speed of the motor M, or any combination thereof. When at least one of the gearshift operating devices and at least one of the accelerator operating devices is operated in an improper order, at least one of motor suppression control and a predetermined notification is executed.

This allows for motor suppression control or a specified notification to be performed depending on the tractor's configuration, allowing for appropriate start of travel or work.

(2) In each of the above embodiments, the notification unit 26 may be any device configured to notify the operator. For example, the notification unit 26 may be a speaker or voice alarm generator capable of issuing a voice or warning sound, an LED, lamp, or warning light capable of notifying using a lighting or flashing pattern, a monitor or information terminal capable of displaying text or images, or a combination of these. This allows for notifications that are easy for the operator to see depending on the situation.

(3) In each of the above embodiments, the traveling device is not limited to wheels and may be a crawler.

(4) In each of the above embodiments, the control unit 50 is not limited to being composed of the above-mentioned functional blocks, 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 the functional blocks may be combined. Furthermore, the functions of the control unit 50 are not limited to the above-mentioned functional blocks, and may be realized by a method executed by any functional block. Furthermore, some or all of the functions of the control unit 50 may be composed of software. A program related to the software is stored in any storage device and executed by a processor such as a CPU included in the control unit 50 or a separately provided processor.

The present invention can be applied to electric agricultural vehicles such as tractors, harvesters, and rice transplanters, as well as various electric work vehicles that travel electrically to perform various tasks.

10. Front wheels (running gear)
11 Rear wheels (running gear)
15 Hydrostatic continuously variable transmission 26 Notification unit 37 Accelerator lever (accelerator operating device)
38 HST pedal (HST operation tool/gear change operation tool)
39 PTO lever (PTO operation tool/gear change operation tool)
54 Motor control unit M Motor

Claims (9)

a motor that drives at least one of the traveling device and the working device;
a speed change operating device that changes the speed of rotational power that drives the traveling device or the working device;
an accelerator operation tool for increasing or decreasing the motor rotation speed of the motor;
a motor control unit that controls the motor rotation speed in response to an operation of the accelerator operation tool,
When the electric work vehicle is stopped while the motor is running and it is detected that the accelerator operating device has been operated after the gear change operating device has been operated, the operation is detected as an inappropriate operation that could lead to a sudden start of the vehicle, and motor suppression control is performed to suppress an increase in motor output. 2. The electric work vehicle according to claim 1 , wherein the predetermined notification for avoiding the inappropriate operation is given when the motor rotation speed is 0 rotations or a predetermined first rotation speed or less after the speed change operating device is operated. the motor control unit, when the speed change device is operated while the motor rotation speed is equal to or less than the first rotation speed, sets the motor rotation speed to equal to or less than a second rotation speed that is greater than the first rotation speed and at which a predetermined vehicle does not take off ,
3. The electric work vehicle according to claim 2, wherein the notification is made by the rotation sound of the motor. the motor control unit controls the motor rotation speed so as not to exceed an idling rotation speed, which is a predetermined rotation speed greater than 0 rotations, while the motor is operating;
3. The electric work vehicle according to claim 2 , wherein the notification is made by the rotation sound of the motor. The electric work vehicle according to claim 2 , further comprising a notification unit that issues the notification. The electric work vehicle described in claim 5, wherein the notification unit is a speaker that emits a warning sound, and the notification is made by the warning sound. The electric work vehicle of claim 5, wherein the notification unit is a warning light, and the notification is made by turning on or flashing the warning light. The motor further includes a hydrostatic continuously variable transmission that changes the speed of the rotational power transmitted to the traveling device,
2. The electric work vehicle according to claim 1, wherein the speed change operating device includes an HST operating device that operates the angle of a swash plate of the hydrostatic continuously variable transmission. The electric work vehicle according to claim 1, wherein the speed change device includes a PTO device that changes the speed of the rotational power transmitted from the motor to the work device.