JP7614071B2 - Electric Tractor - Google Patents

Description

The present invention relates to an electric tractor that distributes and supplies power to multiple electric motors from a common battery.

Patent Document 1 discloses an electric tractor. The tractor includes an electric motor for driving, an electric motor for working, and a battery. The electric motor for driving drives the wheels. The electric motor for working drives the rotary tilling device. The battery supplies power to each motor. The rotation speed of the electric motor for working is detected by a work rotation speed detection sensor. The tractor includes an operation control unit that functions as a driving speed control means and a work power control means. When the operation control unit detects that the detected value of the rotation speed of the electric motor for working has fallen below a set value, it controls the rotation speed of the driving motor to decrease accordingly.

JP 2013-150560 A

If the total power consumption of the motors exceeds the power supply of the battery, the burden on the battery increases, causing it to deteriorate. In this regard, Patent Document 1 does not disclose the relationship between the control of multiple electric motors to reduce the burden on the battery.

The present invention was made in consideration of the above circumstances, and its purpose is to protect the battery from overload while maintaining good operability.

Means for solving the problems and effects

The problem that the present invention aims to solve is as described above. Next, we will explain the means for solving this problem and its effects.

According to a first aspect of the present invention, an electric tractor having the following configuration is provided. That is, the electric tractor includes a hydraulic pump, a pump motor, a PTO motor, a battery, and a control unit. The hydraulic pump supplies hydraulic oil to a hydraulic device provided in the traveling vehicle. The pump motor is an electric motor that drives the hydraulic pump. The PTO motor is an electric motor that drives a PTO shaft provided in the traveling vehicle. The battery is common to the pump motor and the PTO motor, and supplies power to these motors. The control unit controls the distribution of power to the pump motor and the PTO motor. When an overload state of the battery is detected, the control unit reduces the power supplied to the PTO motor in priority to reducing the power supplied to the pump motor.

This helps prevent unstable operation of hydraulic equipment while also preventing battery overload.

According to a second aspect of the present invention, an electric tractor having the following configuration is provided. That is, the electric tractor includes a hydraulic pump, a pump motor, a traveling motor, a battery, and a control unit. The hydraulic pump supplies hydraulic oil to a hydraulic device provided in the traveling body. The pump motor is an electric motor that drives the hydraulic pump. The traveling motor is an electric motor that is driven to travel the traveling body. The battery is common to the pump motor and the traveling motor, and supplies power to these motors. The control unit controls the distribution of power to the pump motor and the traveling motor. When an overload state of the battery is detected, the control unit reduces the power supplied to the traveling motor in priority to reducing the power supplied to the pump motor.

This prevents the hydraulic equipment from becoming unstable while also preventing battery overload. In addition, the machine's speed will be reduced to notify the operator of battery overload at an early stage.

According to a third aspect of the present invention, there is provided an electric tractor having the following configuration. That is, the electric tractor includes a PTO motor, a traveling motor, a battery, and a control unit. The PTO motor is an electric motor that drives a PTO shaft equipped on a traveling body. The traveling motor is an electric motor that is driven to travel the traveling body. The battery is common to the PTO motor and the traveling motor, and supplies power to these motors. The control unit controls the distribution of power to the PTO motor and the traveling motor. When an overload state of the battery is detected, the control unit reduces the power supplied to the traveling motor in priority to reducing the power supplied to the PTO motor.

This allows the battery to be quickly and reliably relieved from overload by prioritizing deceleration during driving, which is likely to result in a relatively reliable reduction in load.

According to a fourth aspect of the present invention, an electric tractor having the following configuration is provided. That is, the electric tractor includes a PTO motor, a traveling motor, a battery, and a control unit. The PTO motor is an electric motor that drives a PTO shaft equipped on a traveling body. The traveling motor is an electric motor that is driven to travel the traveling body. The battery is common to the PTO motor and the traveling motor, and supplies power to these motors. The control unit controls the PTO motor and the traveling motor. When an overload state of the battery is detected, the control unit reduces the rotation speed of the traveling motor, and reduces the rotation speed of the PTO motor in conjunction with this.

This makes it possible to suppress disruptions to the working pitch even if the travel speed is reduced due to the detection of an overload.

According to a fifth aspect of the present invention, an electric tractor having the following configuration is provided. That is, the electric tractor includes a hydraulic pump, a pump motor, a PTO motor, a traveling motor, a battery, and a control unit. The hydraulic pump supplies hydraulic oil to a hydraulic device equipped in the traveling vehicle. The pump motor is an electric motor that drives the hydraulic pump. The PTO motor is an electric motor that drives a PTO shaft equipped in the traveling vehicle. The traveling motor is an electric motor that drives to travel the traveling vehicle. The battery is common to the pump motor, the PTO motor, and the traveling motor, and supplies power to these motors. The control unit controls the distribution of power to the pump motor, the PTO motor, and the traveling motor. When an overload state of the battery is detected, the control unit reduces the power supplied to the traveling motor from among the pump motor, the PTO motor, and the traveling motor with the highest priority. If an overload state of the battery is detected even after the power supplied to the drive motor is reduced, the control unit reduces the power supplied to the PTO motor in priority over reducing the power supplied to the pump motor.

This makes it possible to prevent battery overload while ensuring stable operation of hydraulic equipment. By prioritizing driving deceleration, which can be expected to reduce the load to a certain extent, over PTO deceleration, battery overload can be quickly and reliably eliminated.

1 is a block diagram showing the overall configuration of an electric tractor according to an embodiment of the present invention; 5 is a graph illustrating the control of the present embodiment when an overload occurs in the first battery. 4 is a flowchart illustrating a process performed in an electric drive controller.

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the overall configuration of an electric tractor 1 according to one embodiment of the present invention. FIG. 2 is a graph explaining the control of this embodiment when an overload occurs in the first battery 21. FIG. 3 is a flowchart explaining the processing performed in the electric drive controller 61.

The electric tractor 1 shown in FIG. 1 is configured as an agricultural tractor. The electric tractor 1 has a traveling machine body 2 as a vehicle body portion capable of traveling in a farm field.

A working machine 3 can be connected to the traveling machine body 2. Examples of the working machine 3 include a cultivator (manufacturing machine), a plow, a fertilizer applicator, a grass cutter, a seed sowing machine, etc. Various types of working machines 3 can be attached to the traveling machine body 2 as needed.

The front of the running body 2 is supported by a pair of left and right front wheels 4, and the rear of the running body 2 is supported by a pair of left and right rear wheels 5.

A transmission device 6 is disposed at the rear of the traveling body 2. Inside the transmission device 6, a speed change mechanism consisting of, for example, a gear train is disposed. The transmission device 6 changes the speed of the power input from the traveling motor 41 described below. The power changed in the transmission device 6 is transmitted to the front wheels 4 and the rear wheels 5.

A travel motor 41, a pump motor 42, and a PTO motor 43 are arranged at appropriate positions on the electric tractor 1.

The driving motor 41 generates driving force to rotate the rear wheels 5 and the front wheels 4. The output shaft of the driving motor 41 is connected to the input shaft of the transmission device 6.

The pump motor 42 drives the hydraulic pump 7. The hydraulic pump 7 is a device for supplying hydraulic oil to various hydraulic devices, and is disposed at an appropriate position on the traveling machine body 2.

The hydraulic pump 7 can supply hydraulic oil to any hydraulic device, but an example of this is a lift actuator (not shown). The lift actuator is provided at the rear of the traveling body 2 to adjust the height and attitude of the work machine 3 attached to the traveling body 2. In addition, the hydraulic pump 7 can be used to supply hydraulic oil to a hydraulic steering device (not shown), for example.

The PTO motor 43 drives the PTO shaft 8. The PTO shaft 8 can be connected to the input shaft of the work machine 3 when the work machine 3 is connected to the traveling machine body 2. The PTO motor 43 can drive the work machine 3 via the PTO shaft 8.

The traction motor 41, the pump motor 42, and the PTO motor 43 are all configured as electric motors. These motors can be configured as, for example, permanent magnet synchronous motors (PM motors), but are not limited to this.

The traveling body 2 includes a first battery (battery) 21, a second battery 22, a BMS unit 26, a DC/DC converter 27, a traveling inverter 46, a pump inverter 47, and a PTO inverter 48.

The first battery 21 is a high-voltage battery. The first battery 21 supplies power to the drive motor 41, the pump motor 42, and the PTO motor 43.

The traveling body 2 is provided with a BMS unit (battery management device) 26. BMS is an abbreviation for battery management system. The BMS unit 26 is configured as a computer and has the function of monitoring the voltage, temperature, etc. of the first battery 21 and detecting abnormalities. The BMS unit 26 is electrically connected to the electric drive controller 61 described below.

The second battery 22 is a battery for the auxiliary equipment, and its output voltage is lower than that of the first battery 21. The second battery 22 supplies power to the auxiliary equipment 28. There are various possible types of auxiliary equipment 28, but examples of such accessories include an electric motor for a cooling fan and an electric motor for a pump that circulates cooling water.

The DC/DC converter 27 converts the high voltage of the first battery 21 to a lower voltage for charging the second battery 22.

The first battery 21 and the second battery 22 may be configured as any type of battery, for example a lithium ion secondary battery.

The drive inverter 46, the pump inverter 47, and the PTO inverter 48 are each electrically connected to the three corresponding electric motors. All three inverters are electrically connected to a common first battery 21. These inverters boost the voltage of the first battery 21 and supply it to the drive motor 41, the pump motor 42, and the PTO motor 43.

The traveling machine body 2 is equipped with an electric drive controller (control unit) 61. The traveling inverter 46, the pump inverter 47, and the PTO inverter 48 are each electrically connected to the electric drive controller 61.

The electric drive controller 61 is configured as a known computer and includes a CPU, ROM, RAM, etc. The electric drive controller 61 controls the operation of each of the three transmission motors via the three inverters. The electric drive controller 61 controls the rotation speed of each of the electric motors, and generally, the rotation speed of the electric motor is closely related to the power consumption. Therefore, it can be said that the electric drive controller 61 essentially controls the distribution of power from the first battery 21 to the traction motor 41, the pump motor 42, and the PTO motor 43 via the three inverters.

The electric drive controller 61 also monitors the temperature and load of each component, and automatically limits operation of each electric motor as necessary.

The electric tractor 1 is equipped with a plurality of operating members 51 and a plurality of operating sensors 52.

The operating members 51 are members such as levers, pedals, dials, switches, and touch panels that can be operated by the operator. In this embodiment, all of the operating members 51 are well-known, so they will be described briefly. As an example, the operating members 51 include a steering handle, a travel shift lever, a reverse lever, a travel mode switch, a PTO shift lever, a draft lever, and a work equipment lift lever.

The steering handle is an operating member for changing the turning angle of the front wheels 4. The travel speed change lever is an operating member for changing the travel speed of the electric tractor 1. The reverse lever is an operating member for switching the electric tractor 1 between forward and reverse. The travel mode switch is an operating member for switching, for example, between two-wheel drive using only the rear wheels 5 and four-wheel drive using the rear wheels 5 and the front wheels 4. The PTO speed change lever is an operating member for changing the rotation speed of the PTO shaft 8. The draft lever is an operating member for indicating the traction force when performing draft control that maintains a predetermined traction force by automatically changing the height of the work implement 3 according to the traction load. The work implement lift lever is an operating member for changing the height of the work implement 3.

The operation sensor 52 is configured as, for example, a potentiometer, a switch, an optical sensor, a touch panel sensor, etc. The operation sensor 52 can detect the operation performed by the operator on the operation member 51. The operation sensor 52 is electrically connected to the tractor-side controller 62 described below.

The traveling machine body 2 is equipped with a tractor-side controller 62. The tractor-side controller 62 is configured as a known computer and is equipped with a CPU, ROM, RAM, etc.

The tractor controller 62 and the electric drive controller 61 are electrically connected and can transmit and receive control signals. In this embodiment, the control signals are exchanged using CAN communication, but communication may be performed using other methods.

Signals transmitted from the tractor-side controller 62 to the electric drive controller 61 include, for example, a travel speed command value for the traveling body 2, a rotation speed command value for the PTO shaft 8, and a torque command value for the traveling motor 41 and the PTO motor 43. In addition to these, for example, the above-mentioned travel mode, the operating position of the reverse lever, the control gain, the release level of the hydraulic valve, etc. can be transmitted from the tractor-side controller 62 to the electric drive controller 61.

Signals transmitted from the electric drive controller 61 to the tractor-side controller 62 include, for example, the actual values of the rotational speed and torque of the travel motor 41, the pump motor 42, and the PTO motor 43. In addition, for example, the charge rate of the first battery 21, the margin up to the output allowable value of the first battery 21, the motor slip rate, etc. can be transmitted from the electric drive controller 61 to the tractor-side controller 62.

The electric tractor 1 further includes a meter device 53 and a hydraulic controller 54.

The meter device 53 can display the status of the electric tractor 1, such as the vehicle speed, so that the operator can visually confirm it. The meter device 53 is electrically connected to the tractor-side controller 62.

The hydraulic controller 54 can, for example, control the operation of the lifting actuator via an electromagnetic valve (not shown).

Next, the control performed by the electric drive controller 61 will be described with reference to FIG. 2. Note that the graph in FIG. 2 is shown conceptually for the purpose of explanation, and each electric motor is not necessarily controlled strictly as shown in the graph.

Let us consider a case where an electric tractor 1 with a working machine 3 (e.g., a tiller) attached to a traveling body 2 performs work while traveling. Electricity from the first battery 21 is supplied to the traveling motor 41, the pump motor 42, and the PTO motor 43, and the three motors are driven simultaneously.

Normally, as shown in graph (a) of Figure 2, the total power supplied from the first battery 21 to the three motors does not exceed the output tolerance of the first battery 21.

For example, when the electric tractor 1 approaches a hard field, the tilling resistance increases, and the load on the PTO motor 43 that drives the implement 3 increases. As a result, consider the case where the overall output exceeds the output tolerance of the first battery 21, as shown in FIG. 2(b).

To reduce the load on the first battery 21, the electric drive controller 61 can also issue deceleration commands to the travel motor 41, the pump motor 42, and the PTO motor 43. This configuration can also reduce the power supply to the first battery 21. However, if the hydraulic pressure of the pump motor 42 decreases, the operation of various hydraulic devices becomes unstable.

The electric drive controller 61 of this embodiment is configured to decelerate the travel motor 41 or the PTO motor 43 in priority to the speed of the pump motor 42 when the power supply from the first battery 21 exceeds a predetermined threshold.

Specifically, when an overload is detected as shown in FIG. 2(b), the electric drive controller 61 immediately controls only the driving motor 41 to decelerate appropriately. This reduces the power consumption of the driving motor 41 as shown in FIG. 2(c), and as a result, the overall output also decreases.

2(c), where only the travel motor 41 is decelerated, the relationship between the rotational speed of the travel motor 41 and the rotational speed of the PTO motor 43, which was maintained in (a) and (b), changes. Since it is undesirable for the grain size of the tilled soil to be unstable, the electric drive controller 61 of this embodiment, after achieving the state of FIG. 2(c), immediately controls the PTO motor 43 to decelerate to a speed that corresponds to the decelerated travel speed.

As a result, the outputs of the traction motor 41 and the PTO motor 43 are rebalanced as shown in FIG. 2(d). As a result, the load on the first battery 21 is not excessive, and stable work quality can be obtained.

Throughout (a) to (d) of FIG. 2, the output of the pump motor 42 is maintained constant. This allows the hydraulic equipment to operate stably and reliably.

In this manner, in this embodiment, if the outputs of the travel motor 41, pump motor 42, and PTO motor 43 are an overload for the first battery 21, the travel motor 41 is decelerated first. Therefore, the operator driving the electric tractor 1 can be easily notified of the overload of work by the deceleration of the travel speed. Also, in this embodiment, only the travel speed decreases first, but this is transient, and the PTO motor 43 immediately decelerates to follow the travel speed. In this manner, the vehicle speed and PTO speed are controlled in coordination, eliminating the need for the operator to make fine adjustments.

The above describes the case where the load on the PTO motor 43 increases and the first battery 21 becomes overloaded, but essentially the same control is performed when the load on the pump motor 42 increases and the first battery 21 becomes overloaded.

Next, the control performed by the electric drive controller 61 will be explained with reference to the flowchart in Figure 3.

When the process of FIG. 3 is started, the electric drive controller 61 controls the drive inverter 46, the pump inverter 47, and the PTO inverter 48 so as to drive the drive motor 41, the pump motor 42, and the PTO motor 43 at speeds based on commands received from the tractor-side controller 62 (step S101).

Next, the electric drive controller 61 detects the output of the travel motor 41, the pump motor 42, and the PTO motor 43, and calculates a total value. The output of each motor can be obtained by detecting the current value flowing through each motor using a current sensor, or by providing a torque sensor on the output shaft, etc.

The electric drive controller 61 determines whether the total output value of the three motors exceeds a predetermined value (step S102). If the total output value does not exceed the predetermined value, the process returns to step S101.

If it is determined in step S102 that the total output of the three motors exceeds the predetermined value, the electric drive controller 61 controls the driving inverter 46 to decelerate the driving motor 41 while monitoring the total output (step S103). The driving motor 41 continues to decelerate until the total output of the three motors falls below the predetermined value. In other words, the driving motor 41 decelerates by an amount equivalent to the difference between the total output of the three motors and the predetermined value.

When the deceleration of the traveling motor 41 is completed, the electric drive controller 61 controls the PTO inverter 48 to reduce the speed of the PTO motor 43 (step S104). The deceleration of the PTO motor 43 is performed in proportion to the amount by which the speed of the traveling motor 41 is decelerated by the control of step S103. This allows the disturbance in the working pitch (in other words, the tilling pitch) of the electric tractor 1 to be quickly restored.

The rotation speed of the driving motor 41 can be obtained, for example, simply based on a command from the electric drive controller 61 to the driving motor 41. In addition, for example, a rotation sensor can be provided on one of the transmission shafts (not shown) that constitute the transmission device 6, and the rotation speed of the driving motor 41 can be obtained based on the detection of this rotation sensor. By obtaining the rotation speed of the driving motor 41 before and after step S103, it is possible to obtain how much the driving motor 41 has decelerated in step S103.

With regard to the pump motor 42, the electric drive controller 61 controls the pump inverter 47 to maintain the same speed as in step S101 (step S105).

Next, the electric drive controller 61 attempts to gradually restore the speeds of the traveling motor 41 and the PTO motor 43 that were once reduced (step S106). That is, it is considered that the total output value of the three motors will be lower than the predetermined value of step S102 with a certain margin due to the processing of steps S103 and S104. Also, if the large load detected in step S102 subsides in a short time, the reduction in the load will also be a margin. The electric drive controller 61 increases the speeds of the traveling motor 41 and the PTO motor 43 while monitoring the total output value of the three motors in a manner that eliminates the above-mentioned margin. The amount by which the speeds of the traveling motor 41 and the PTO motor 43 increase per unit time is appropriately determined so that the balance of the rotation speeds of both motors is maintained. The processing of step S106 is performed until the total output value of the three motors reaches the predetermined value of step S102 or the speeds of the traveling motor 41 and the PTO motor 43 reach the original command value.

The electric drive controller 61 waits while repeating the process of step S106 until a predetermined time has elapsed (step S107). This predetermined time is set to an appropriate length while taking into consideration the prevention of hunting of the driving speed.

The electric drive controller 61 then determines whether the drive motor 41, pump motor 42, and PTO motor 43 can operate with the original command value described in step S101 (step S108). This determination can be made by checking whether the current speeds of the drive motor 41 and PTO motor 43 have already reached the original command value, and whether the current total output value of the three motors is sufficiently lower than the predetermined value in step S102.

If it is determined in step S108 that each motor can operate with the original command value, the process returns to step S101. If it is determined that each motor cannot operate with the original command value, an error is generated and notified to the operator (step S109).

As described above, the electric tractor 1 of this embodiment includes the hydraulic pump 7, the pump motor 42, the PTO motor 43, the first battery 21, and the electric drive controller 61. The hydraulic pump 7 supplies hydraulic oil to the hydraulic device of the traveling body 2. The pump motor 42 is an electric motor that drives the hydraulic pump 7. The PTO motor 43 is an electric motor that drives the PTO shaft 8 of the traveling body 2. The first battery 21 is common to the pump motor 42 and the PTO motor 43, and supplies power to these motors. The electric drive controller 61 controls the distribution of power to the pump motor 42 and the PTO motor 43. When an overload state of the first battery 21 is detected, the electric drive controller 61 reduces the power supplied to the PTO motor 43 in priority to reducing the power supplied to the pump motor 42.

This prevents the operation of the hydraulic equipment from becoming unstable while also preventing overloading of the first battery 21.

The electric tractor 1 of this embodiment also includes a traveling motor 41. The traveling motor 41 is an electric motor that is driven to make the traveling body 2 travel. The first battery 21 is common to the pump motor 42 and the traveling motor 41, and supplies power to these motors. The electric drive controller 61 controls the distribution of power to the pump motor 42 and the traveling motor 41. When an overload state of the first battery 21 is detected, the electric drive controller 61 reduces the power supplied to the traveling motor 41 in priority over reducing the power supplied to the pump motor 42.

This makes it possible to prevent overloading of the first battery 21 while preventing the operation of the hydraulic equipment from becoming unstable. In addition, the speed of the traveling machine body 2 is reduced, so that the operator can be notified of an overload on the first battery 21 at an early stage.

In the electric tractor 1 of this embodiment, when an overload state of the first battery 21 is detected, the electric drive controller 61 reduces the power supplied to the traction motor 41 in priority over reducing the power supplied to the PTO motor 43.

This allows the overload on the first battery 21 to be quickly and reliably eliminated by prioritizing deceleration during driving, which is likely to result in a relatively reliable reduction in load.

In the electric tractor 1 of this embodiment, when an overload state of the first battery 21 is detected, the electric drive controller 61 reduces the rotation speed of the traction motor 41 and, in conjunction with this, reduces the rotation speed of the PTO motor 43.

This makes it possible to suppress disruptions to the working pitch even if the travel speed is reduced due to the detection of an overload.

In the electric tractor 1 of this embodiment, when an overload state of the first battery 21 is detected, the electric drive controller 61 reduces the power supplied to the driving motor 41 as a first priority among the pump motor 42, the PTO motor 43, and the driving motor 41. If an overload state of the first battery 21 is still detected after reducing the power supplied to the driving motor 41, the electric drive controller 61 reduces the power supplied to the PTO motor 43 as a first priority over reducing the power supplied to the pump motor 42.

This makes it possible to prevent overload on the first battery 21 while ensuring the stability of the hydraulic equipment operation. By prioritizing driving deceleration, which can be expected to reduce the load to a certain extent, over PTO deceleration, overload on the first battery 21 can be quickly and reliably eliminated.

The above describes a preferred embodiment of the present invention, but the above configuration can be modified, for example, as follows:

In the above embodiment, the priority order of power supply is as follows: first, pump motor 42; second, PTO motor 43; and third, traction motor 41. However, for example, second, traction motor 41 may be second and PTO motor 43 may be third.

The deceleration of the PTO motor 43 shown in step S104 of FIG. 3 may be performed simultaneously with the deceleration of the traction motor 41 in step S103.

The speed of the PTO motor 43 may be adjusted manually by the operator instead of automatically in step S104.

The processing in FIG. 3 may be performed on the tractor side controller 62 instead of the electric drive controller 61.

If an overload of the first battery 21 is detected and the rotational speed of the travel motor 41 is set to zero in step S103, but the total output of each motor exceeds a predetermined value and is in an overloaded state, it is preferable to immediately slow down the rotational speed of the PTO motor 43. For example, when there are large stones in the soil in a mountainous field, the load on the PTO motor 43 from the PTO motor 43 may be quite large even if the travel body 2 is stopped. Furthermore, if the rotational speed of the PTO motor 43 is set to zero but the total output of each motor exceeds a predetermined value and is in an overloaded state, the rotational speed of the pump motor 42 may be controlled to be slowed down.

1 Electric tractor 2 Traveling machine body 7 Hydraulic pump 8 PTO shaft 21 First battery (battery)
41 Travel motor 42 Pump motor 43 PTO motor 61 Electric drive controller (control unit)

Claims (5)

A hydraulic pump that supplies hydraulic oil to a hydraulic device provided on the traveling machine body;
a pump motor which is an electric motor that drives the hydraulic pump;
A PTO motor which is an electric motor that drives a PTO shaft provided on the traveling machine body;
a common battery for supplying power to the pump motor and the PTO motor;
a control unit that controls distribution of power to the pump motor and the PTO motor;
Equipped with
the control unit, when an overload state of the battery is detected, reduces the power supplied to the PTO motor in priority over reducing the power supplied to the pump motor. A hydraulic pump that supplies hydraulic oil to a hydraulic device provided on the traveling machine body;
a pump motor which is an electric motor that drives the hydraulic pump;
A traveling motor which is an electric motor that drives the traveling machine body to travel;
a common battery for supplying power to the pump motor and the traveling motor;
a control unit that controls distribution of electric power to the pump motor and the traveling motor;
Equipped with
the control unit, when an overload state of the battery is detected, reduces the power supplied to the traction motor in priority to reducing the power supplied to the pump motor. A PTO motor which is an electric motor that drives a PTO shaft provided on the traveling machine body;
A traveling motor which is an electric motor that drives the traveling machine body to travel;
a common battery for supplying power to the PTO motor and the traction motor;
a control unit that controls distribution of electric power to the PTO motor and the traction motor;
Equipped with
the control unit, when an overload state of the battery is detected, reduces the power supplied to the traction motor in priority over reducing the power supplied to the PTO motor. A PTO motor which is an electric motor that drives a PTO shaft provided on the traveling machine body;
A traveling motor which is an electric motor that drives the traveling machine body to travel;
a common battery for supplying power to the PTO motor and the traction motor;
a control unit for controlling the PTO motor and the driving motor;
Equipped with
The control unit reduces the rotation speed of the driving motor when an overload state of the battery is detected, and reduces the rotation speed of the PTO motor in conjunction with the reduction in the rotation speed of the driving motor. A hydraulic pump that supplies hydraulic oil to a hydraulic device provided on the traveling machine body;
a pump motor which is an electric motor that drives the hydraulic pump;
A PTO motor which is an electric motor that drives a PTO shaft provided on the traveling machine body;
A traveling motor which is an electric motor that drives the traveling machine body to travel;
a common battery for supplying power to the pump motor, the PTO motor, and the driving motor;
a control unit that controls distribution of electric power to the pump motor, the PTO motor, and the traveling motor;
Equipped with
When an overload state of the battery is detected, the control unit reduces the power supplied to the driving motor with the highest priority among the pump motor, the PTO motor, and the driving motor,
an electric tractor, characterized in that if an overload state of the battery is detected even after the power supplied to the traction motor has been reduced, the control unit reduces the power supplied to the PTO motor in priority to reducing the power supplied to the pump motor.

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