JP7519984B2 - Electric work vehicle - Google Patents

Description

The present invention relates to an electric work vehicle that is configured to perform, for example, ground work or other work while the vehicle body is moving, and that is equipped with an electric motor capable of driving the vehicle body and a battery that supplies driving power to the electric motor.

In this type of electric work vehicle, as described in Patent Document 1, for example, when the battery power is consumed, charging is performed from an external power supply device connected via a connection connector. In this type of electric work vehicle, charging is performed by inserting a portable operation key and operating the key switch, with power being supplied to the electrical equipment including the control device.

JP 2021-957 A

Charging the battery takes a long time, and the driver may leave the vehicle while the operation key is still attached. This allows someone other than the driver to freely operate the key, making it possible for someone else to drive and operate the work vehicle. This has resulted in the problem of the work vehicle becoming a victim of theft. To prevent this from becoming a victim of theft, if the operation key is removed during charging, the charging process will not be carried out after that, and the vehicle will not be able to be fully charged.

Therefore, there was a demand for a system that would allow the vehicle to be charged to a sufficient level while avoiding the risk of theft, even if the driver leaves the vehicle when charging takes a long time.

The electric work vehicle according to the present invention is characterized by comprising an electric motor capable of driving a vehicle body to travel, a battery which supplies driving power to the electric motor and is chargeable by an external power supply device, a connection part to which a power supply connector of the power supply device can be connected, a control device which controls the operation of the electric motor and controls the charging state by the power supply device, and a start command means which switches the control device to an operable state by being manually operated with a portable operation key in the vicinity of the vehicle body or with the operation key attached to an attachment part, and when the control device is in the operable state and the power supply connector is connected to the connection part, the power supply device is configured to switch to a charging mode when the power supply connector is in a connected state and in the charging mode, charging is performed by the power supply device in a state in which running by the electric motor is restricted , and after charging by the power supply device has started, charging by the power supply device is continued even if the state is switched to a state in which the operation key is separated from the vehicle body or the operation key is detached from the attachment portion, and in the charging mode, when the switch is operated with the power supply connector detached from the connection portion after charging is completed, the charging mode is switched from the charging mode to a state in which running by the electric motor is permitted .

According to the present invention, when the start command means is manually operated while the operation key is close to the vehicle body or while the operation key is attached to the attachment portion, the control device switches to an operable state. Then, when the control device is in an operable state and in a connected state where the power supply connector is connected to the connection portion, the control device switches to a charging mode, and the battery is charged in this charging mode. Even if the driver moves away from the vehicle body while holding the operation key during charging, charging continues, and the battery can be charged to a sufficient amount.

When the driver holds the operation key and is away from the vehicle, the operation key is also away from the vehicle, so even if someone tries to drive the vehicle, the operation key is not present and the control device cannot operate the electric motor, so there is no risk of theft.

As a result, even if the driver leaves the vehicle when charging takes a long time, it is possible to charge the vehicle to a sufficient level while still avoiding the risk of theft of the work vehicle.

In the present invention, it is preferable that the control device switches to the charging mode when the control device is switched to the operable state while the power supply connector is connected to the connection portion.

According to this configuration, when switching to charging mode, it is necessary to first switch the control device to an operable state with the power supply connector connected to the connection part. In contrast, in a configuration in which the control device is first switched to an operable state and then the power supply connector is connected to the connection part, there is a risk of, for example, the power supply connector being mistakenly connected to the connection part when the electric motor is set to an operable state. However, according to this configuration, since the power supply connector is connected to the connection part first, it is clear that charging operation is required, and there is little risk of operational error.

In the present invention, it is preferable that the control device is configured to automatically switch to a non-operating state when charging is completed if charging is continued using the power supply device after the operation key is switched to a state in which it is separated from the vehicle body or the operation key is switched to a state in which it is removed from the mounting portion.

With this configuration, charging continues while the operation key is away from the vehicle body, and when charging is completed, the control device automatically switches to a non-operating state. Therefore, even if the start command means is manually operated by someone who does not have the operation key, the control device will not become operable, ensuring operational safety.

In the present invention, it is preferable that the operation key is configured to be able to be inserted into the insertion portion serving as the mounting portion.

According to this configuration, when the driver uses the operation key, the driver needs to insert the operation key into the insertion section, so the driver can easily recognize that the operation key is attached to the vehicle body. For example, if a wireless operation key is used, the driver may leave the operation key in a location separate from the driving section of the vehicle body and move away from the vehicle body, but with the above configuration, such a disadvantage can be easily avoided.
In the present invention, it is preferable that the manual operation is a push-type switch.

FIG. FIG. 4 is a left side view showing the arrangement of an inverter and the like. FIG. FIG. 2 is a block diagram showing a configuration for charging. 4 is a flowchart of a control operation.

The embodiment for carrying out the present invention will be explained with reference to the drawings. In the following explanation, unless otherwise specified, the direction of the arrow F in the drawings is "forward", the direction of the arrow B is "backward", the direction of the arrow L is "left", and the direction of the arrow R is "right". The direction of the arrow U in the drawings is "up" and the direction of the arrow D is "down".

[Overall configuration of the tractor]
The following describes a tractor as an example of an electric work vehicle according to the present invention. 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 has a machine frame 2 and a driving section 3. The machine frame 2 is supported by left and right front wheels 10 and left and right rear wheels 11.

The cover member 12 is disposed at the front of the aircraft. The driving section 3 is provided behind the cover member 12. In other words, the cover member 12 is disposed in front of the driving section 3.

The driver's unit 3 has a protective frame 30, a driver's seat 31, and a steering wheel 32. An operator 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.

The tractor is equipped with a running battery 4. The cover member 12 is configured to be able to swing 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 a closed state, the running battery 4 is covered by the cover member 12.

As shown in FIG. 2, the tractor is equipped with an inverter 14 and an electric motor M. The driving battery 4 supplies power to the inverter 14. The inverter 14 converts DC power from the driving battery 4 into AC power and supplies it to the electric motor M. The electric 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 electric 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 is changed between the hydraulic pump 15a and the hydraulic motor 15b. The hydrostatic continuously variable transmission 15 is configured so that the gear ratio can be changed steplessly.

The rotational power output from the hydraulic motor 15 b is transmitted to the transmission 16 .
The rotational power transmitted to the transmission 16 is changed in speed by a 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. In this way, the left and right front wheels 10 and the left and right rear wheels 11 are driven.

As shown in Figures 2 and 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 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 working device is connected to the mid PTO shaft 17 or the rear PTO shaft 18, the working device is driven by the rotational power of the mid PTO shaft 17 or the rear PTO shaft 18.
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.

[Configuration related to motor control]
As shown in Fig. 4, the configuration related to the control of the electric motor M includes an accelerator device 33, a control device 34 that controls the operation of the electric motor M, and the inverter 14. The accelerator device 33 is provided near the steering wheel 32. Although not shown, the accelerator device 33 includes a lever that can be swung and a potentiometer that is operated by swung operation of the lever. The accelerator device 33 is connected to the control device 34. The control device 34 is connected to the inverter 14 via a signal harness 35. The control device 34 is configured to issue a command to the inverter 14 in response to a command from the accelerator device 33. The inverter 14 is configured to adjust the power supplied from the driving battery 4 to the electric motor M in response to a command from the control device 34 to control the output of the electric motor M.

[Configuration related to charging]
As shown in FIG. 4, the driving battery 4 can be charged by an external power supply device KD.
The tractor is provided with a charging connection portion 37 to which a power supply connector 36 of the power supply device KD can be connected. The charging connection portion 37 is provided inside the cover member 12 and is exposed to the outside when the cover member 12 is swung open. The control device 34 controls the operation of the electric motor M and also controls the charging state by the power supply device KD.

The charging connection 37 is compliant with commonly used standards. With the power supply connector 36 connected to the charging connection 37, the driving battery 4 is charged via the power supply line 39. The driving battery 4 supplies high-voltage power (e.g., tens to hundreds of volts) to the driving electric motor M via the power supply line 39.

The driving battery 4 is constructed, for example, using a lithium-ion battery, and although not shown, is constructed by stacking many small low-voltage unit cells, and is stored in a storage case that is covered on the outside in a sealed state. Therefore, heat tends to build up inside the battery, and once the internal temperature rises, it is difficult to lower the temperature. Therefore, the driving battery is equipped with a temperature sensor 40 as a temperature detection means for detecting the internal temperature. The detection information of the temperature sensor 40 is input to the control device 34.

In addition to the traction battery 4, the tractor is equipped with an electrical equipment battery 41 that supplies power to the control device 34 and other electrical equipment. The electrical equipment battery 41 supplies low-voltage (12 volts) power to drive the electrical equipment. The electrical equipment battery 41 is charged with power supplied from the traction battery 4 via a DC/DC converter 42.

The driving unit 3 is provided with a switching operation unit 44 as a start command means capable of switching the control device 34 between an operable state and an inoperative state. The switching operation unit 44 is provided with an insertion section 46 as an attachment section into which a portable operation key 45 can be inserted and attached, and a push-button switch 47 that can be manually pressed. With the operation key 45 inserted and attached into the insertion section 46, the control device 34 can be switched from an inoperative state to an operable state by pressing the switch 47. The operation key 45 functions as a key that can only be identified in the work vehicle, similar to a general vehicle key.

The operation panel 43 is provided with a meter panel 48 that displays, for example, the vehicle's running state, operating state, and battery information (charge level and temperature). The meter panel 48 is connected to the control device 34, and its operation is controlled by the control device 34.

The control device 34, inverter 14, driving battery 4, DC/DC converter 42, meter panel 48, charging connection unit 37, etc. are connected to each other via a signal harness 35 of the CAN (Controller Area Network) system so that data can be communicated. The control device 34 communicates with the charging connection unit 37 via a charging communication harness 49, and information such as whether the power supply connector 36 is connected to the charging connection unit 37 and the charging current required on the work vehicle side are transmitted. Signals are also configured to be able to communicate between the charging connection unit 37 and the power supply device KD. Operation information of the switching operation unit 44 is input to the control device 34.

[Charging Control]
When the control device 34 is switched to an operable state with the power supply connector 36 connected to the charging connection portion 37, the control device 34 switches to a charging mode. In the charging mode, the control device 34 is configured to charge the driving battery 4 by the power supply device KD.

The control device 34 is configured to prohibit the vehicle body from moving during charging operation from when the power supply device KD starts charging the driving battery with the power supply connector 36 connected to the charging connection portion 37 until charging of the driving battery 4 is completed. Specifically, the control device 34 is configured not to drive the electric motor M during charging operation.

The control device 34 is configured to continue charging by the power supply device KD after starting charging by the power supply device KD, even if the operation key 45 is switched to a state where it is removed from the plug-in portion 46. The control device 34 is configured to automatically switch to a non-operating state when charging is completed if charging by the power supply device KD is continued after the operation key 45 is switched to a state where it is removed from the plug-in portion 46.

The specific charging control of the control device 34 will be explained below with reference to the flowchart in Figure 5.

When charging the driving battery 4, the operator connects the power supply connector 36 of the power supply device KD to the charging connection section 37. Next, in the switching operation section 44 provided on the operation panel 43 of the driving section 3, the operator inserts the operation key 45 into the insertion section 46 and presses the switch 47. When the control device 34 recognizes this, it switches to the charging mode (steps #1, #2, #3).

When the charging mode is selected, the output of the inverter 14 is stopped to inhibit the operation of the electric motor M (step #4). Next, the necessary information is sent via the charging communication harness 49 to the power supply device KD to supply power, and charging of the driving battery 4 by the power supply device KD is started (step #5).

The driving battery 4 is charged to a preset charge state, and when it is fully charged, charging is stopped (steps #6 and #7).

When charging is completed, it is determined whether the operation key 45 is inserted into the insertion portion 46 (step #8). If it is determined that the operation key 45 has been removed and is not attached, it is assumed that the driver removed the operation key 45 while charging was in progress and took it away, so the control device 34 is switched to a non-operating state and the power supply is forcibly cut off (step #09).

Therefore, if charging continues using the power supply device KD after the operation key 45 is switched to a state where it is removed from the plug-in portion 46, the control device 34 will automatically switch to a non-operating state when charging is completed.

If the operation key 45 is inserted when charging is completed, the operator removes the power supply connector 36 of the power supply device KD to disconnect it from the charging connection part 37, and then presses the switch 47 to cancel the charging mode (steps #08, #10, #11). At this time, the output of the inverter 14 is restarted to enable the electric motor M to operate, and the inhibited state of the electric motor M is released (step #12). Therefore, while the driving battery 4 is being charged, the electric motor M will not be operated even if an operation to drive the vehicle is performed, and the vehicle is prohibited from moving and driving.

[Another embodiment]
(1) In the above embodiment, the operation key 45 is configured to be inserted into the insertion portion 46 for attachment. However, instead of this configuration, the operation key 45 may be configured to be capable of wireless communication with a receiving portion on the vehicle body, and when the switch 47 is operated while the operation key 45 is close to the vehicle body, the control device 34 may be switched to an operable state.

(2) In the above embodiment, after the operation key 45 is switched to a state where it is removed from the mounting portion, the control device 34 is automatically switched to a deactivated state when charging is completed. However, instead of this configuration, for example, the control device may be configured to be capable of communicating with the driver's mobile terminal and notify the driver that charging is completed, or the driver may be notified by voice.

(3) In the above embodiment, the control device 34 is configured to switch to the charging mode when the power supply connector 36 is connected to the charging connection portion 37 and is switched to an operable state. However, instead of this configuration, the control device 34 may be configured to switch to the charging mode when the power supply connector 36 is connected to the charging connection portion 37 after the control device 34 has been switched to an operable state in advance.

The present invention can be applied not only to tractors, but also to various electric work vehicles such as rice transplanters, combine harvesters, and construction machinery.

34 Control device 36 Power supply connector 37 Connection portion 44 Start command means
45 Operation key 46 Insertion part (attached part)
47 Switch
KD Power supply device M Electric motor

Claims (5)

An electric motor capable of driving the vehicle body;
a battery that supplies driving power to the electric motor and is chargeable by an external power supply device;
a connection portion to which a power supply connector of the power supply device can be connected;
a control device that controls the operation of the electric motor and controls a charging state by the power supply device;
a start command means for switching the control device to an operable state by manually operating a portable operation key in a state where the operation key is close to the vehicle body or in a state where the operation key is attached to a mounting portion,
The control device includes:
When the device is in the operable state and in a connected state in which the power supply connector is connected to the connection portion, the device is configured to switch to a charging mode,
an electric work vehicle configured such that, in the charging mode, charging is performed by the power supply device with traveling by the electric motor restricted , and that after charging by the power supply device has begun, charging by the power supply device is continued even if the operation key is switched to a state in which it is separated from the vehicle body or removed from the attachment portion, and when charging is completed, a determination is made as to whether the operation key is in proximity to the vehicle body or inserted into the attachment portion, and when the manual operation is performed with the power supply connector removed from the connection portion after charging is completed, the electric work vehicle is configured to switch from the charging mode to a state in which traveling by the electric motor is possible . The electric work vehicle according to claim 1, wherein the control device switches to the charging mode when the control device is switched to the operable state while the power supply connector is connected to the connection portion. The electric work vehicle according to claim 1 or 2, wherein the control device is configured to automatically switch to a non-operating state when charging is completed if charging is continued using the power supply device after the operation key is switched to a state in which it is separated from the vehicle body or the operation key is switched to a state in which it is removed from the mounting portion. The electric work vehicle according to any one of claims 1 to 3, wherein the operation key is configured to be inserted and attached to the insertion portion as the attachment portion. 2. The electric work vehicle according to claim 1, wherein the manual operation is a push-type switch.

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