JP2023110656A - electric work vehicle - Google Patents

Abstract

To provide an electric work vehicle that enables a driver to physically feel a travelling state similar to that felt when driving a conventional work vehicle with an engine equipped with a transmission mechanism, during operation of changing output power from a transmission.SOLUTION: The electric work vehicle comprises: an electric motor M; travelling devices 10 and 11; a transmission 16 that transmits power from the electric motor M to the travelling devices 10 and 11; a control unit 5 that controls behavior of the electric motor M; and a manual operation tool 40 that gives the control unit a change instruction requiring change of output power from the transmission 16 to 5. On the basis of the change instruction, the control unit 5 controls the electric motor M in such a manner that behavior of the electric motor M simulates behavior of a work vehicle with an engine an engine, the behavior of the work vehicle being performed during operation of changing the output power.SELECTED DRAWING: Figure 6

Description

The present invention is a battery-driven electric working vehicle that is powered by a motor driven by electric power supplied from a battery.

Patent Document 1 discloses an electric working vehicle that uses a motor instead of an engine as a power source. The transmission includes a continuously variable transmission called HMT (Hydraulic Mechanical Transmission) and a transmission comprising a clutch and a gear transmission mechanism.

Patent Document 2 discloses a battery-driven electric working vehicle that includes a working device, a battery, a motor driven by electric power supplied from the battery, a transmission, and a traveling device (front wheels and rear wheels). is disclosed. The transmission has a continuously variable transmission called HST (Hydraulic Static Transmission), changes the speed of driving force received from the motor, and transmits it to the left and right rear wheels. The motor basically rotates at a constant speed, and changing the swash plate angle of the HST changes the rotation speed of the rear wheels, that is, the vehicle speed. Therefore, a transmission mechanism using a clutch can be omitted.

JP 2013-141955 A Japanese Patent Application Laid-Open No. 2021-104768

Aiming for a carbon-neutral society that eliminates greenhouse gas emissions as a whole, in recent years, electric work vehicles that use an electric motor instead of an engine as a power source, as shown in Patent Document 1 and Patent Document 2, have attracted attention. It is Unlike an engine, an electric motor has the advantage that its torque is constant in most rotation ranges, and can output stable rotational power from low speed to high speed.

However, most of the drivers of electric working vehicles are accustomed to driving engine working vehicles in which the engine is used as a power source and the shift operation is performed by operating the clutch. For this reason, in the electric working vehicle as described above, the behavior of the vehicle body when the clutch operation or the gear shifting operation is performed is different from that of the engine working vehicle, which gives a sense of incongruity. In order to deal with this uncomfortable feeling, there is a demand for an electric working vehicle that can experience the same running state as a conventional engine working vehicle equipped with a transmission mechanism when changing the power output from the transmission. .

An electric working vehicle according to the present invention includes an electric motor, a traveling device, a transmission for transmitting power from the electric motor to the traveling device, a control unit for controlling behavior of the electric motor, and output power from the transmission. and a manual operation tool that gives a change command to the control unit requesting a change of
The control unit controls the electric motor based on the change command so that the behavior of the electric motor simulates the behavior of the engine work vehicle during a change operation.

According to this configuration, when the driver operates the manual operation tool that gives the control unit a change command requesting a change in the output power from the transmission (deceleration, acceleration, PTO on/off, etc.), the electric motor is operated as an engine work vehicle. behaves to imitate the behavior when such a change operation is performed in Whether this manual operation tool is a dummy operation tool that does not directly change the output power from the transmission or a real operation tool that actually changes the output power from the transmission, this manual operation tool By operating the tool, the driver can experience the same running and working conditions as in the engine working vehicle equipped with the conventional transmission mechanism at the time of the change operation.

An engine working vehicle equipped with a conventional clutch transmission mechanism by operating a pseudo-clutch operation tool when changing the output power from the transmission, even if the electric working vehicle is not equipped with a transmission mechanism using a clutch. By controlling the electric motor, it is possible to simulate the behavior of the vehicle body that can be felt when changing the transmission output power that accompanies the clutch operation. In this case, if the change operation tool for changing the output power from the transmission is configured to also serve as the pseudo clutch operation tool, there is no need to physically provide the pseudo clutch operation tool, which is convenient. Therefore, in one preferred embodiment of the present invention, the manual operation tool is a change operation tool for changing the output power of the transmission, and the change operation tool also functions as a pseudo clutch operation tool. , the change command by the change operation tool includes a pseudo clutch operation command, and the control unit controls the electric motor based on the change command and the pseudo clutch operation command. In this configuration, for example, when the driver operates the change operation tool to change the vehicle speed, a shift command as a change command and a pseudo clutch operation command are given to the control unit. The control unit performs shift control based on the shift command, and simulates the behavior of the vehicle body that occurs during clutch shift (shift involving clutch operation) in an engine work vehicle equipped with a clutch shift mechanism, based on the pseudo clutch operation command. , which controls the electric motor. In some cases, the change operation tool and the pseudo clutch operation tool may be provided separately.

In an engine work vehicle equipped with a conventional clutch speed change mechanism, the behavior of the vehicle body that can be felt at the time of clutch speed change differs from person to person, and the desired behavior also differs from person to person. For this reason, it is preferable to prepare a plurality of simulated behavior modes that simulate the behavior of the vehicle body (behavior of the electric motor) based on the simulated clutch operation command, and select one according to the driver's preference and driving conditions. Of course, it is also preferable to be able to select a mode in which the simulated behavior of the vehicle body based on the pseudo clutch operation command is not performed. Therefore, in one preferred embodiment of the present invention, the control unit is provided with a plurality of different simulated behavior modes for simulating behavior of the electric motor based on the change command.

Although a motor is used as a power source instead of an engine, there are also electric working vehicles equipped with a conventional transmission consisting of a clutch and a gear type transmission mechanism. If the present invention is applied to such an electric working vehicle, the above effects can be obtained. Accordingly, in one preferred embodiment of the present invention, the manual operation tool includes a shift operation tool for operating a shift mechanism provided in the transmission, and the change command by the shift operation tool is Based on the shift command, the control unit controls the electric motor and sends a control signal to the actuator of the shift mechanism. Furthermore, in another preferred embodiment of the present invention, the manual operation tool includes a clutch operation tool for operating a clutch provided in the transmission, and the change command by the clutch operation tool is a clutch Based on the clutch operation command, the control unit controls the electric motor and sends a control signal to the actuator of the clutch.

Furthermore, since most of the working devices mounted on the working vehicle are driven by the power (PTO power) branched from the transmission, they are provided with a PTO clutch for turning ON/OFF the PTO power transmission. In an engine work vehicle, when the PTO clutch is operated, an instantaneous load fluctuation occurs in the engine, so the driver often senses the behavior of the vehicle body and performs appropriate work based thereon. Therefore, even when the PTO clutch is operated, the vehicle body behavior that is familiar to the engine working vehicle is required. For this reason, in one preferred embodiment of the present invention, the manual operation tool includes a PTO clutch operation tool for operating a PTO clutch mounted on the transmission, and the control unit controls the PTO clutch. The electric motor is controlled based on the change command from the clutch operation tool, and a control signal is sent to the actuator of the PTO clutch.

It is a left view of a tractor. It is a left view which shows arrangement|positionings, such as an inverter. It is a figure which shows the flow of power transmission. It is a figure which shows the structure of a transmission. FIG. 3 is a functional block diagram showing a configuration related to an operation control system; FIG. FIG. 3 is a functional block diagram showing a configuration relating to a pseudo clutch control system; FIG.

A mode for carrying out the present invention will be described based on the drawings. In the following description, unless otherwise specified, the direction of arrow F in the drawings is "forward", the direction of arrow B is "rear", the direction of arrow L is "left", and the direction of arrow R is "left". Let's say "right". In addition, the direction of arrow U in the drawing is defined as "up", and the direction of arrow D is defined as "down".

[Overall configuration of tractor]
A tractor, which is an example of an electric working vehicle, will be described as one embodiment. As shown in FIG. 1, the tractor includes left and right front wheels 10, left and right rear wheels 11, and a cover member 12 as traveling devices.

The tractor also has a body frame 2 and a driving section 3 . The body frame 2 is supported by left and right front wheels 10 and left and right rear wheels 11 .

The cover member 12 is arranged at the front part of the machine body. The operating section 3 is provided behind the cover member 12 . In other words, the cover member 12 is arranged in front of the driving section 3 .

The driving section 3 has a protective frame 30 , a driver's seat 31 and a steering wheel 32 . A driver can sit on the driver's seat 31 . This allows the driver to get on the driving section 3 . By operating the steering wheel 32, the left and right front wheels 10 are steered. The driver can perform various driving operations in the driving section 3 .

The tractor has a battery 4 which is a running battery. Further, the cover member 12 is configured to be swingable around an opening/closing axis Q extending in the lateral direction of the machine body. Thereby, the cover member 12 is configured to be openable and closable. The battery 4 is covered with the cover member 12 when the cover member 12 is in the closed state.

As shown in FIG. 2, the tractor includes an inverter 14 and an electric motor (hereinafter simply referred to as motor) M. As shown in FIG. Battery 4 supplies power to inverter 14 . The inverter 14 converts the DC power from the battery 4 into AC power and supplies it to the motor M. The motor M is driven by AC power supplied from the inverter 14 .

As shown in FIGS. 2 and 3, the tractor includes a transmission 16 that transmits power from the motor M to the front wheels 10 and left and right rear wheels 11, which are traveling devices. A hydrostatic continuously variable transmission (hereinafter referred to as HST 15 ) is arranged at the front stage of the transmission 16 . The HST 15 has an HST pump 15a and an HST motor 15b. The HST pump 15a is driven by rotational power from the motor M. By driving the HST pump 15a, rotational power is output from the HST motor 15b. The HST 15 is configured such that the rotation power is changed between the HST pump 15a and the HST motor 15b in a stepless manner.

Rotational power output from the HST motor 15b is distributed to the left and right rear wheels 11 through a gear transmission mechanism 16A arranged in the middle stage of the transmission 16 and a rear wheel differential gear mechanism 16B arranged in the middle stage of the transmission 16. be. Since this tractor is of the four-wheel drive type, the rotational power from the gear transmission mechanism 16A of the transmission 16 is distributed to the left and right front wheels 10 via the front wheel drive shaft 9 and the front wheel differential gear mechanism.

The tractor also has a mid PTO shaft 17 and a rear PTO shaft 18, as shown in FIG. Rotational power output from the motor M is distributed in the transmission 16 to the HST pump 15a, the mid PTO shaft 17, and the rear PTO shaft 18. Thereby, the mid PTO shaft 17 and the rear PTO shaft 18 rotate.

A work device attached to the mid PTO shaft 17 or the rear PTO shaft 18 is driven by the rotational power of the mid PTO shaft 17 or the rear PTO shaft 18 . For example, as shown in FIG. 2 , in this embodiment, the mid PTO shaft 17 is connected to the mowing device 19 , and the rotary power of the mid PTO shaft 17 drives the mowing device 19 .

If a working device is connected to the mid PTO shaft 17 or the rear PTO shaft 18, the rotational power of the mid PTO shaft 17 or the rear PTO shaft 18 drives the working device. For example, as shown in FIG. 2, a mower 19 is connected to the mid PTO shaft 17 in this embodiment. The rotary power of the mid PTO shaft 17 drives the lawn mower 19 . Although not shown, a tillage device is connected to the rear PTO shaft 18 when tillage work is performed.

[Transmission structure]
As shown in FIG. 4, the transmission 16 includes a gear transmission mechanism 16A, a rear wheel differential gear mechanism 16B, and a PTO mechanism 16C. The PTO mechanism 16</b>C has a first shaft 21 , a first gear mechanism 22 , a second gear mechanism 23 , a second shaft 24 , a third gear mechanism 25 , a first clutch 26 and a second clutch 27 . The first clutch 26 and the second clutch 27 function as PTO clutches, and each of them is configured to be able to change its state between an on state that transmits power and an off state that does not transmit power.

An output shaft MA of the motor M is connected to the first shaft 21 . The first shaft 21 is connected to the rotating shaft of the HST pump 15a. Rotational power is transmitted from the first shaft 21 to the first gear mechanism 22 when the first clutch 26 is in the engaged state. Further, when the second clutch 27 is in the engaged state, rotational power is transmitted from the first shaft 21 to the second shaft 24 .

The rotational power transmitted to the first gear mechanism 22 is transmitted to the mid PTO shaft 17 via the second gear mechanism 23 . The rotational power transmitted to the second shaft 24 is transmitted to the rear PTO shaft 18 via the third gear mechanism 25 .

The rotational power transmitted to the HST pump 15a is changed in speed via hydraulic pressure in the HST 15 and output from the HST motor 15b. Rotational power output from the HST motor 15b is transmitted via the third shaft 28 to the gear transmission mechanism 16A. The rotational power transmitted to the gear transmission mechanism 16A is changed in speed by the gear transmission mechanism 16A and distributed to the front wheel drive shaft 9 and the rear wheel differential gear mechanism 16B. Left and right front wheels 10 are driven by the rotational power transmitted to the front wheel drive shaft 9 . The left and right rear wheels 11 are driven by the rotational power transmitted to the rear wheel differential gear mechanism 16B.

[Operation control system]
As shown in FIG. 5, the tractor provides a control unit 5 which controls the behavior of the motor M and changes in the transmission state of the transmission 16, and provides change commands to the control unit 5 to change the power output from the transmission 16. A manual operation tool 40 is provided. The manual operation tool 40 includes an accelerator operation tool 41 , a work operation tool 43 and a travel operation tool 42 . The manual operation tool 40 is not particularly limited, and may be, for example, a lever or a button. Further, the manual operation tool 40 is provided in the operation section 3, for example.

The control unit 5 has a motor control section 51 , a travel control section 52 and a work control section 53 .

When the accelerator operating tool 41 is manually operated, a signal corresponding to the operation is sent to the motor control section 51 . The motor control unit 51 controls the output rotation speed of the motor M by controlling the inverter 14 based on the signal. That is, the motor control unit 51 controls the output rotation speed of the motor M according to the manual operation of the accelerator operating tool 41 .

If the travel operation tool 42 is a shift operation tool for adjusting the angle of the pump swash plate of the HST 15 , when this shift operation tool is manually operated, a signal corresponding to the operation is sent to the travel control unit 52 . The travel control unit 52 controls the pump swash plate angle of the HST pump 15a based on the signal. As the pump swashplate angle changes, the gear ratio at HST 15 changes. That is, the travel control unit 52 controls the shift state of the HST 15 according to the manual operation of the travel operation tool 42 .

In addition, when the pump swash plate 58 is in the neutral state, the HST 15 is in a state in which the HST motor 15b does not output rotational power. The HST 15 also outputs rotational power in the forward and reverse directions to the left and right front wheels 10 and the left and right rear wheels 11 according to the angle of the pump swash plate 58 . That is, the HST 15 is configured to be capable of outputting rotational power in forward and reverse directions to the left and right front wheels 10 and the left and right rear wheels 11 in accordance with the manual operation of the travel operating tool 42 .

If the travel operation tool 42 is a gear change operation tool that switches between the high speed/low speed gear part of the gear transmission mechanism 16A, the gear speed of the gear transmission mechanism 16A is controlled according to the manual operation of the travel operation tool 42 . Note that the shift operation tool is a kind of change operation tool used for changing the output power of the transmission 16 .

When the work operation tool 43 functioning as a PTO clutch operation tool is manually operated, a signal corresponding to the operation is sent to the work control unit 53 . Based on the signal, the work control unit 53 sends control signals to the actuators of the first clutch 26 and the second clutch 27 to control the ON/OFF states of the first clutch 26 and the second clutch 27 . Thereby, the work control unit 53 switches the states of the mid PTO shaft 17 and the rear PTO shaft 18 between a rotating state and a non-rotating state.

[Pseudo clutch control]
As shown in FIG. 6 , the motor control section 51 has a pseudo clutch behavior control section 511 and a pseudo behavior table 512 . The pseudo-clutch behavior control unit 511 controls the motor M based on a change command requesting a change in the output power from the transmission 16, here a change in the rotation speed, by the travel operation tool 42 and the work operation tool 43, which are the manual operation tools 40. The motor M is controlled so that M behaves like a pseudo-clutch.

The pseudo-clutch behavior is vehicle body behavior during a change operation that can occur in an engine working vehicle when a gear change operation is performed on the HST 15 or the gear transmission mechanism 16A by the traveling operation tool 42, or when a power transmission switching operation is performed on the PTO mechanism 16C by the work operation tool 43. This is the vehicle body behavior that is caused to the tractor by controlling the motor M so as to simulate (acceleration and deceleration). Note that the shift in the HST 15 does not include clutch operation, but here, the simulated behavior of the vehicle body behavior that occurs during a change operation that does not include clutch operation is also referred to as pseudo clutch behavior.

For example, if the traveling operation tool 42 is a gear change operation tool for changing gears of the gear transmission mechanism 16A, this gear change operation tool also functions as a pseudo clutch operation tool. In other words, the change command generated by operating the shift operating tool includes the shift command and the pseudo clutch operation command. The travel control section 52 of the control unit 5 drives the shift actuator of the gear transmission mechanism 16A based on the shift command to switch the gear stage of the gear transmission mechanism 16A to a desired gear stage. At the same time, the pseudo-clutch behavior control section 511 of the control unit 5 controls the motor M in order to simulate the behavior of the vehicle during gear shifting that can occur in the engine work vehicle.

Further, when the work operation tool 43 is a PTO switching operation tool that switches power transmission to the PTO mechanism 16C using the first clutch 26 or the second clutch 27, this PTO switching operation tool can also be used as a pseudo clutch operation tool. Function. That is, the change command generated by operating the PTO switching operation tool includes the switching command and the pseudo clutch operation command. The travel control section 52 of the control unit 5 drives the clutch actuator of the first clutch 26 or the second clutch 27 of the PTO mechanism 16C based on the switching command to create desired transmission of rotational power of the PTO mechanism 16C. At the same time, the pseudo-clutch behavior control section 511 of the control unit 5 controls the motor M in order to simulate the vehicle body behavior when the power transmission is changed in the PTO mechanism 16C, which can occur in the engine working vehicle.

When the engine control program that brings about the behavior of the motor M that simulates such vehicle characteristics is created as a simulated behavior mode, first, in the engine work vehicle, the vehicle body that occurs when the power output of the transmission 16 is changed is changed. Behavior is determined experimentally. An engine control program for causing the motor M to behave so as to create the vehicle body behavior obtained here is created as a simulated behavior mode.

The vehicle body behavior that occurs when power transmission is changed in the PTO mechanism 16C also varies depending on the type of work device to which rotational power is transmitted by the PTO mechanism 16C. Also, different vehicle body behaviors appear depending on the gear stage switched in the gear transmission mechanism 16A. Furthermore, the preferred vehicle body behavior simulated by the motor M and experienced by the driver differs depending on the driver. Therefore, the simulated behavior table 512 stores a plurality of different simulated behavior modes for causing the electric motor to simulate behavior. The simulated clutch behavior control section 511 selects an appropriate simulated behavior mode based on rules set in advance according to the operation by the driver, and controls the simulated behavior of the motor M based on the selected simulated behavior mode. do. When there is only one simulated behavior mode to simplify the configuration, or when adopting a configuration in which different simulated behavior modes are created by changing parameters in one simulated behavior mode, the simulated behavior table 512 is becomes unnecessary.

[Another embodiment]
(1) In the above-described embodiment, the HST 15 is arranged in the transmission 16 as a continuously variable transmission, but the present invention is not limited to this. Other belt type continuously variable transmissions or planetary gear type continuously variable transmissions may be used. Furthermore, the continuously variable transmission may be omitted and the transmission 16 may be configured only by a gear-type stepped device.

(2) In the above-described embodiment, the manual operation tool 40 is connected to the control unit 5 in a by-wire system, but it may be linked to the operation target by a mechanical link. In this case as well, the control unit 5 is provided with a signal indicating the operation content of the manual operation tool 40 that requires the motor M to simulate the behavior of the change operation.

It should be noted that the configurations disclosed in the above-described embodiments (including other embodiments; the same shall apply hereinafter) can be applied in combination with configurations disclosed in other embodiments unless there is a contradiction. Moreover, the embodiments disclosed in this specification are merely examples, and the embodiments of the present invention are not limited thereto, and can be modified as appropriate without departing from the scope of the present invention.

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

4: Battery 14: Inverter 16: Transmission 16A: Gear transmission mechanism 16C: PTO mechanism 19: Lawn mower 40: Manual operation tool 41: Accelerator operation tool 42: Travel operation tool 43: Work operation tool 5: Control unit 51: Motor control Section 511: pseudo-clutch behavior control section 512: pseudo-behavior table

Claims (6)

an electric motor;
a running device;
a transmission that transmits power from the electric motor to the traveling device;
a control unit that controls the behavior of the electric motor;
a manual operation tool for providing a change command to the control unit to change the output power from the transmission;
The electric working vehicle, wherein the control unit controls the electric motor based on the change command so that the behavior of the electric motor simulates the behavior of the engine working vehicle during a change operation. The manual operation tool is a change operation tool for changing the output power of the transmission, the change operation tool also functions as a pseudo clutch operation tool, and the change command by the change operation tool includes a pseudo clutch operation command. 2. The electric working vehicle according to claim 1, wherein said control unit controls said electric motor based on said change command and said pseudo clutch operation command. 3. The electric working vehicle according to claim 1, wherein the control unit is provided with a plurality of different simulated behavior modes for simulating the behavior of the electric motor based on the change command. The manual operation tool includes a shift operation tool that operates a shift mechanism provided in the transmission, the change command by the shift operation tool is a shift command, and the control unit is configured to operate based on the shift command. The electric working vehicle according to any one of claims 1 to 3, wherein the electric motor is controlled and a control signal is sent to an actuator of the transmission mechanism. The manual operation tool includes a clutch operation tool for operating a clutch provided in the transmission, the change command by the clutch operation tool is a clutch operation command, and the control unit is based on the clutch operation command. 5. The electric working vehicle according to any one of claims 1 to 4, wherein a control signal is sent to an actuator of the clutch while controlling the electric motor. The manual operating tool includes a PTO clutch operating tool for operating a PTO clutch provided in the transmission, and the control unit controls the electric motor based on the change command from the PTO clutch operating tool. 6. The electric working vehicle according to any one of claims 1 to 5, further comprising: sending a control signal to an actuator of the PTO clutch.

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