JP2024005666A - work vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a work vehicle in which a load of steering operation can be changed according to a situation during work travel.

SOLUTION: A work vehicle includes: a travel vehicle body; a steering wheel that changes a travel direction of the travel vehicle body; a steering wheel for operating the steering wheel; a steering sensor 21 that detects operation of the steering wheel; and a control unit 20 that changes an operation load of the steering wheel. At the time of work in a field, when the control unit 20 determines that turning operation of the steering wheel is performed on the basis of a detection value of the steering sensor 21, the control unit sets the operation load of the steering wheel to be smaller than that when the turning operation is not detected.

SELECTED DRAWING: Figure 3

COPYRIGHT: (C)2024,JPO&INPIT

Description

The present invention relates to a work vehicle such as a tractor.

Conventionally, the steering load of a work vehicle is quite different when driving on general roads and when driving for work, so inexperienced drivers have to operate the steering wheel when driving on general roads in the same way as when driving for work. This can cause the vehicle to wobble left and right.

Therefore, conventionally, a mode changeover switch is provided to switch the mode between work mode and non-work mode, and when the non-work mode is selected, the steering wheel operation relative to the steering operation speed is lower than when the work mode is selected. A work vehicle in which the forwarding speed is set to be low is known (Prior Document 1).

Such a work vehicle can suppress wandering when not working.

Japanese Patent Application Publication No. 10-109660

However, in work vehicles, it may be desirable for the steering operation load to fluctuate even during work, but with the above technology it is not possible to change the steering operation load depending on the situation during work driving. .

SUMMARY OF THE INVENTION An object of the present invention is to provide a work vehicle that can appropriately change the steering operation load depending on the situation during work travel.

The first invention is
A running vehicle body,
a steering wheel that changes the traveling direction of the traveling vehicle body;
a steering wheel for operating the steering wheel;
a steering sensor that detects operation of the steering wheel;
A control unit that changes the operating load of the steering wheel,
When working in the field,
The work vehicle is characterized in that, when the control unit determines that a turning operation of the steering wheel has been performed based on a detection value of the steering sensor, the control unit reduces the operating load of the steering wheel compared to when the turning operation is not detected. be.

The second invention is
In the working vehicle of the first aspect of the present invention, the steering sensor detects the angular velocity of the operation of the steering wheel, and the control section determines that the angular velocity is a turning operation when the angular velocity exceeds a predetermined value set in advance.

The third invention is
The steering wheel has a structure in which the angle of the steering wheel starts to change when the operating angle of the steering wheel becomes a predetermined effective angle or more, and the control unit determines whether or not the turning operation is performed within a range that is less than the effective angle. , the working vehicle according to the second aspect of the present invention, in which the turning operation is not determined in a range equal to or greater than the effective angle.

The fourth invention is
A structure in which the angle of the steering wheel starts to change when the operating angle of the steering wheel exceeds a predetermined effective angle,
Within a range less than the effective angle, when determining that a turning operation of the steering wheel has been performed, the control unit reduces the operating load of the steering wheel than when the turning operation is not detected;
Within a range equal to or greater than the effective angle, when it is determined that a turning operation of the steering wheel has been performed, the control section increases the operation load of the steering wheel in a stepwise manner or according to a predetermined rule than when the turning operation is not detected. This is the work vehicle of the second invention, in which the load is gradually reduced continuously.

The fifth invention is
A hydraulic power steering mechanism is used to operate the steered wheels by the steering wheel,
In the work vehicle of the first aspect of the present invention, the control unit changes the operating load of the steering wheel by controlling a hydraulic circuit of the hydraulic power steering mechanism.

The sixth invention is
An electric power steering mechanism using an electric motor is used to operate the steered wheels by the steering wheel,
In the work vehicle of the first aspect of the present invention, the control unit changes the operating load of the steering wheel by controlling the electric power steering mechanism.

According to the first aspect of the present invention, when turning, the operating load on the steering wheel is lightened, so that turning can be performed with a small force. The burden on the driver can be reduced by reducing the operating load when turning, which requires a large amount of operation. When the vehicle is not turning, such as when traveling straight, the operating load is heavier than when turning, which makes it possible to appropriately change the steering operation load, such as ensuring stability when traveling straight.

According to the second aspect of the present invention, when a turning operation is determined by detecting the operation angle, a certain degree of angle is required to determine whether or not it is a turning operation, but in that case, the load may not be changed during the operation. This can easily cause an uncomfortable feeling when operating the machine. In contrast, if the angular velocity is used to determine whether or not a turning operation is to be performed, the driver can perform the operation without feeling any discomfort, since it is possible to determine whether or not it is a turning operation almost immediately after the start of the operation, rather than based on the operation angle.

According to the third invention, the operating load of the steering wheel is changed by changing the angle of the steering wheel, assuming that the steering wheel does not rotate unless the steering wheel rotates by more than a predetermined effective angle (play range). This is done before the steering wheels start turning and is not done after the steering wheels start turning and the vehicle body starts turning, so it is possible to prevent a phenomenon where the load on the steering wheel is changed while the vehicle body is turning and causing a strange feeling.

According to the fourth aspect of the present invention, assuming that the steering wheel does not rotate unless the steering wheel rotates by more than a predetermined effective angle (play range), after the steering wheel rotates and the vehicle body starts turning, the vehicle body Even if the load on the steering wheel is changed during a turn, it is done gradually, so there is less discomfort.

According to the fifth aspect of the present invention, a hydraulic power steering mechanism can be used.

According to the sixth aspect of the present invention, an electric power steering mechanism can be used.

A side view of a tractor according to an embodiment of the present invention Plan of the field where the tractor is running Main part configuration diagram of the tractor Top view of the tractor's steering wheel Control configuration diagram of the tractor Diagram showing the hydraulic power steering mechanism (neutral state) that is controlled by the tractor's control unit Diagram showing the hydraulic power steering mechanism (left turning state) that is controlled by the tractor's control unit Diagram showing the hydraulic power steering mechanism (right turning state) that is controlled by the tractor's control unit A diagram showing the electric power steering mechanism that is controlled by the tractor's control unit.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a tractor as an example of a work vehicle according to an embodiment of the present invention. First, the overall configuration of the tractor 1 will be described with reference to FIG. 1.

A tractor 1, which is a working vehicle, is an agricultural tractor that performs work in a field or the like, and is ridden by an operator (also referred to as a worker) and executes a predetermined work while traveling in the field.

In addition, hereinafter, the longitudinal direction refers to the traveling direction of the tractor 1 when it is traveling straight, and the front side of the traveling direction is defined as "front" and the rear side is defined as "rear". The traveling direction of the tractor 1 is a direction from a driver's seat 8 to a steering wheel (steering device) 9, which will be described later, when traveling straight (see FIG. 1).

The left-right direction is a direction horizontally orthogonal to the front-back direction. In the following, left and right will be defined toward the "front" side. That is, when the operator (also referred to as "operator") of the tractor 1 is seated in the driver's seat 8 and facing forward, the left hand side is the "left" and the right hand side is the "right".

The vertical direction is the vertical direction. The front-back direction, the left-right direction, and the up-down direction are orthogonal to each other. Note that each direction is defined for convenience of explanation, and the present invention is not limited to these directions. Furthermore, hereinafter, the tractor 1 may be referred to as a "body" or "vehicle body."

As shown in FIG. 1, the tractor 1 includes a traveling vehicle body 2 and a working machine link mechanism at the rear thereof. The traveling vehicle body 2 includes a vehicle body frame 3, front wheels 4, rear wheels 5, a bonnet 6, an engine E, a control section 7, and a transmission case 10. The vehicle body frame 3 is the main frame of the traveling vehicle body 2.

The front wheels 4 are a pair of left and right wheels, and mainly serve as wheels for steering (steering wheels 4). The rear wheels 5 are a pair of left and right wheels, and mainly serve as driving wheels (drive wheels 5). The tractor 1 may be configured to be able to switch between two-wheel drive (2WD) in which the rear wheels 5 drive, and four-wheel drive (4WD) in which both the front wheels 4 and rear wheels 5 drive. In this case, the driving wheels are both the front wheel 4 and the rear wheel 5.

The bonnet 6 is provided at the front of the vehicle body 2 so as to be openable and closable. The bonnet 6 can be rotated (opened and closed) in the vertical direction with the rear portion as the center of rotation. The bonnet 6 covers the engine E mounted on the vehicle body frame 3 in a closed state. The engine E is a drive source for the tractor 1, and is a heat engine such as a diesel engine or a gasoline engine. Note that the bonnet 6 may rotate around the front portion.

The control section 7 is provided at the upper part of the traveling vehicle body 2, and includes a control seat 8, a steering wheel (steering device) 9, and the like. The cockpit 8 is the seat of the pilot. The steering wheel 9 is operated by the driver when steering the front wheels 4. Note that the control section 7 includes a display section (meter panel) 9a in front of the steering wheel 9 that displays various information.

Further, the control unit 7 includes various operating levers such as a forward/reverse lever, an accelerator lever, a main shift lever, and an auxiliary shift lever, and various operating pedals such as an accelerator pedal, a brake pedal, and a clutch pedal.

Note that 10 is a mission case, 12 is a towing unit, 20 is a control unit, 30 is a GNSS device, S is a navigation satellite, and Vs is a sensor attached to the vehicle body frame 3 to detect the speed of the tractor 1.

FIG. 2 shows how such a tractor 1 works in a field H, and includes a straight process in which it travels straight back and forth in the center, a turning process in which it circles between the straight and reciprocating processes, and a process in which it circles around the periphery. I am working on it.

FIG. 3 is a configuration diagram of the control section 20. A steering sensor 21 is a sensor that detects the angular velocity of the rotation angle of the steering wheel 9 in this embodiment. The detected value of the steering sensor 21 is transmitted to the determination section 20a of the control section 20. On the other hand, the control section 20 is provided with a numerical value setting section 20b, which is constantly input to the judgment section 20a. In this embodiment, a predetermined angular velocity value is preset in the value setting section 20b. The value of the predetermined angular velocity is set to a value that allows it to be reliably determined that the steering wheel 9 has been turned by the driver's steering operation when the predetermined angular velocity is reached. It also serves the function of distinguishing between weak turns when traveling straight and strong turns when near the shore.

As a result, the determining unit 20a compares the value of the input detection signal of the steering sensor 21 with the numerical value set in the numerical value setting unit 20b, and when the two match, it is determined that the turning operation of the steering wheel 9 has been performed. to decide.

In this way, when the determining section 20a determines that a turning operation has been performed, the determining section 20a issues an instruction so that the operating load on the steering wheel 9 is lighter than when the turning operation is not detected. In accordance with the instructions, the operating load on the steering wheel 9 is made lighter than before by using various methods as will be described later.

Note that the above-mentioned detection of the angular velocity of the steering sensor 21 and the determination of a turning operation based on the detection of the angular velocity are performed by determining whether or not a turning operation is to be performed within a range that is less than the effective angle, and in a range that is greater than or equal to the effective angle, the determination of a turning operation is not made. You may choose not to have one. θ in FIG. 4 indicates the effective angle.

That is, assuming that the steering wheels 4, 4 do not rotate unless the steering wheel 9 rotates by more than a predetermined effective angle θ (so-called play range), the operation load of the steering wheel 9 is changed only when the steering wheels 4, 4 do not rotate. 4 starts to change, and is not performed after the steering wheels 4, 4 rotate and the vehicle body 2 begins to turn, so the load on the steering wheel 9 is not changed while the vehicle body 2 is turning. Phenomena such as discomfort can be prevented.

As a modified example, if the angular velocity does not reach the predetermined value by the effective angle θ, and the angular velocity reaches the predetermined value after that, the operating load on the steering wheel 9 may be lightened; Instead of reducing the weight, the load may be gradually reduced stepwise or continuously according to a predetermined rule. This is to reduce discomfort.

Next, an embodiment will be described in which characteristics other than angular velocity are detected by the steering sensor 21 and it is determined that a turning operation of the steering wheel 9 has been performed or will be performed (see FIG. 5).
a. This is an example in which the steering sensor 21 detects the torque applied to the steering wheel 9 and determines that a turning operation has been performed. For example, a strain sensor that detects twisting of the shaft of the steering wheel 9 is used.

At this time, the steering load may be changed in stages according to the magnitude of the torque.
b. This is an example in which the steering sensor 21 detects the turning speed of the steering wheel 9, that is, the circumferential speed, and determines that a turning operation has been performed.

At that time, if a circumferential speed equal to or higher than a predetermined circumferential speed is detected, it is determined that a turning operation has been performed.

Note that it is also possible to make this judgment within the range of play and not to make a judgment beyond that range.

This method of not making a turning judgment in a range exceeding the range of play can also be applied to other embodiments.

Alternatively, instead of detecting the angular velocity, the turning may be determined by detecting the angular acceleration.

An example in which turning is detected using a device other than the steering sensor will be described below (see FIG. 5).
a. The steering wheel turning angle sensor 52 detects the turning angle of the steering wheels 4, 4 of the tractor 1, and when a turning angle greater than a predetermined value occurs, a turn is determined.

In addition, in conjunction with the detection of the turning angle, it is also possible to drive the so-called autolift of the working machine in conjunction with the detection.
b. The load applied to the axles of the steered wheels 4, 4 of the tractor 1 is detected by the load sensor 53 which detects the load on the steered wheel axle, and if a load of a predetermined value or more is applied, it is determined that the vehicle is turning. For example, strain sensors may be attached to the running axes of the steering wheels 4, 4.

At this time, the shared load of the steered wheels 4 may be detected by an axle load sensor. When the shared load exceeds a predetermined value, it is determined that the vehicle has turned, and the load on the steering wheel 9 is reduced.

In addition, at that time, it is desirable that the load on the steering wheel 9 is also changed in stages according to the magnitude of the load applied to the steering wheels 4, 4.
c. Turning is determined by the IMU 54 such as a gyro. The angular velocity around the so-called Z-axis is detected, and if it exceeds a predetermined value, it is determined that the vehicle is turning.
d. When the output value of the traction sensor (draft sensor) 55 exceeds a certain level, it is determined that the vehicle will go straight, and the load on the steering wheel 9 is increased.
e. When the work equipment is lowered using the up/down switch 56, it is determined that the work equipment will move straight and the load is increased.
f. When the tractor 1 in operation reaches the end of the working position (turning position) of the working route in the field, it is determined that it is about to turn, and the load on the steering wheel 9 is lightened.

For this purpose, the GNSS device 30 is installed in advance, and by using it to acquire four points on the outer shape of the field, the shape of the field can be roughly grasped. Alternatively, select the field you want to register from a map app, and roughly grasp the shape of the field from its latitude and longitude information. On the other hand, the overall width, overall length, working position, working width, etc. of the working vehicle are registered. This work route 59 is generated by setting work information (turning pattern, number of surrounding plows, etc.) based on the registered work vehicle information.

In a work vehicle that can use the straight-line assist mode function 57 when traveling straight, when the straight-line assist mode is enabled, it is determined that the vehicle will travel straight, and the load on the steering wheel 9 is increased.

Furthermore, when the straight-ahead assist function changes from valid to invalid, the load on the steering wheel 9 is reduced in anticipation of future turns.

Furthermore, in the embodiments described above, a mode in which the load on the steering wheel 9 is changed and a mode in which it is not changed may be prepared so that the operator can arbitrarily select one. For this selection, a dial method, a switch method, a memory switch method 58, etc. can be adopted.

An example of changing the load regardless of turning will be described below (see FIG. 5).
a. Load can be changed arbitrarily.

An operator or the like can arbitrarily change the load on the steering wheel 9. It is desirable to be able to change the load of the steering wheel 9 to suit people of all ages and genders.

Specifically, the load on the steering wheel 9 can be arbitrarily set using a steering sensitivity dial installed in the cabin including the ROP. Alternatively, a switch may be used instead of a dial. Alternatively, the load can be easily changed by selecting a pre-registered steering wheel 9 load using a memory switch, and furthermore, even after moving to another field, work can be performed under the same steering wheel 9 load conditions as in the previous field.
b. The vehicle speed is detected by a vehicle speed sensor Vs, and the load on the steering wheel 9 is changed according to the vehicle speed.

The load on the steering wheel 9 may be determined in advance in stages according to the vehicle speed range and changed automatically. It may be possible to select whether to enable or disable the vehicle speed-linked load change mode. A switch is provided for selection. Alternatively, it may be a switching dial.

Furthermore, when the vehicle speed is above a certain speed, the load on the steering wheel 9 may not be reduced. This is because it is dangerous.
c. Change the load on the steering wheel 9 depending on the type of gear. For example, it may be changed depending on the positions of the main transmission gear and the auxiliary transmission gear.

In the above embodiment, a case where various sensors become abnormal will be described.
a. If a detection means such as a sensor becomes abnormal, switching of the load on the steering wheel 9 is prohibited. This ensures safety.
b. If a detection means such as a sensor becomes abnormal, issue a warning to that effect.
c. In addition, if a detection means such as a sensor becomes abnormal, the details of the abnormality are displayed in the meter panel 9a.
d. Alternatively, if the detection means such as a sensor becomes abnormal, the load on the steering wheel 9 is returned to the load at the time of shipment from the factory.

Below, a method of changing the load on the steering wheel 9 will be explained.

1. A case will be described in which the load on the steering wheel 9 is changed by the hydraulic power steering mechanism 40.

6, 7(b), and 7(c) are configuration diagrams mainly showing the hydraulic circuit of the hydraulic power steering mechanism 40. FIG. The hydraulic circuit has the following structure.

FIG. 6 shows a neutral state in which the steering wheel 9 is not rotating. Here, 40c is an actuator that changes the variable throttles 40a and 40b in response to instructions from the control unit 20, and the variable throttles 40a and 40b throttle the oil passage to the steering wheel drive hydraulic cylinder 40v as described below. This is a member to be adjusted.

In addition, 40d is a hydraulic device called Orbit Roll (registered trademark, hereinafter the same) that adjusts the amount of hydraulic oil to be sent to the steering wheel drive hydraulic cylinder 40v according to the rotation of the steering wheel 9. be. In addition, the orbit roll 40d is connected to an oil passage switching circuit 40f for switching the rotation direction by a shaft 40e, etc., and depending on the rotation direction of the steering wheel 9, the oil passage switching circuit 40f is changed to the left when turning. 7(a), and when turning right, it also plays the role of switching as shown in FIG. 7(b).

Note that 40g is a return filter, 40h is a relief valve, and 40i is a pump.

Here, when the control unit 20 issues an instruction to the actuator 40c to lighten the load on the steering wheel 9, the actuator 40c loosens the throttles of the variable throttles 40a and 40b. Conversely, when the control section 20 issues an instruction to the actuator 40c to increase the load on the steering wheel 9, the actuator 40c narrows down the apertures of the variable apertures 40a and 40b.

In this way, the load on the steering wheel 9 can be changed.

2. Next, a case will be described in which the electric power steering mechanism 41 changes the load on the steering wheel 9.

FIG. 9 is a diagram showing a schematic configuration of an electric power steering mechanism 41 including a motor control device. In FIG. 9, the electric power steering mechanism 41 includes a motor control device 41a, a motor 41b, a steering wheel 9, a rotating shaft 9b of the steering wheel 9, a reduction gear 41c, and the like.

The instruction signal from the control section 20 is sent to the motor control device 41a. The motor control device 41a generates a motor drive signal based on the signal, and outputs the signal to the motor 41b. The motor 41b to which the motor drive signal is input outputs an auxiliary torque for assisting the steering of the steering wheel 9, and the auxiliary torque is transmitted to the rotating shaft 9b via the reduction gear 41c. As a result, the rotation of the rotating shaft 9b is assisted, making it possible to assist the driver's steering operation and make it lighter.

Note that, as described above, the configuration of the present invention may be realized in software or hardware.

Further, the program of the invention related to the present invention is a program for causing a computer to execute all or some of the steps (or steps, operations, effects, etc.) of the control method of the invention related to the present invention described above. It is a program that operates in cooperation with a computer.

In addition, the recording medium of the invention related to the present invention is a computer capable of performing all or some of the steps (or steps, operations, actions, etc.) of the control method of the invention related to the present invention described above. It is a computer-readable recording medium that records a program to be executed by a computer, and the read program is used in cooperation with a computer.

Note that the above-mentioned "some steps (or steps, operations, effects, etc.)" means one or some steps among the plurality of steps.

Moreover, the above-mentioned "operation of a step (or process, operation, action, etc.)" means the operation of all or part of the above-mentioned steps.

Further, one usage form of the program of the invention related to the present invention is a form in which it is transmitted in a transmission medium such as the Internet, light, radio waves, or sound waves, read by a computer, and operated in cooperation with the computer. It may be.

Further, the recording medium includes a ROM (Read Only Memory) and the like.

Further, a computer is not limited to pure hardware such as a CPU (Central Processing Unit), but may also include firmware, an OS (Operating System), and further peripheral devices.

INDUSTRIAL APPLICABILITY The present invention is a work vehicle that can appropriately change the load of a steering operation depending on the situation while traveling for work, and is most suitable for a tractor.

1 Tractor 2 Traveling vehicle body 3 Vehicle frame 4 Front wheel (steering wheel)
5 Rear wheel (drive wheel)
6 Bonnet 7 Control section 8 Pilot seat 9 Steering wheel 9a Display section 10 Mission case 20 Control section 20a Judgment section 20b Numerical setting section 21 Steering sensor 30 GNSS device 40 Hydraulic power steering mechanism 40a, 40b Variable aperture 40c Actuator 40d Orbit roll 40e Shaft 40f Oil passage switching circuit 40g Return filter 40h Relief valve 40i Pump 41 Electric power steering mechanism 41a Motor control device 41b Motor 41c Reduction gear θ Effective angle E Engine S Navigation satellite Vs Speed detection sensor

Claims (6)

A running vehicle body,
a steering wheel that changes the traveling direction of the traveling vehicle body;
a steering wheel for operating the steering wheel;
a steering sensor that detects operation of the steering wheel;
A control unit that changes the operating load of the steering wheel,
When working in the field,
The work vehicle is characterized in that when the control unit determines that a turning operation of the steering wheel has been performed based on a detection value of the steering sensor, the control unit reduces the operation load of the steering wheel compared to when the turning operation is not detected. The work vehicle according to claim 1, wherein the steering sensor detects the angular velocity of the operation of the steering wheel, and the control section determines that the angular velocity is a turning operation when the angular velocity exceeds a predetermined value set in advance. The steering wheel has a structure in which the angle of the steering wheel starts to change when the operating angle of the steering wheel becomes a predetermined effective angle or more, and the control unit determines whether or not the turning operation is performed within a range that is less than the effective angle. 3. The work vehicle according to claim 2, wherein the turning operation is not determined in a range equal to or larger than the effective angle. A structure in which the angle of the steering wheel starts to change when the operating angle of the steering wheel exceeds a predetermined effective angle,
Within a range less than the effective angle, when determining that a turning operation of the steering wheel has been performed, the control unit reduces the operating load of the steering wheel than when the turning operation is not detected;
Within a range equal to or greater than the effective angle, when it is determined that a turning operation of the steering wheel has been performed, the control section increases the operation load of the steering wheel in a stepwise manner or according to a predetermined rule than when the turning operation is not detected. 3. The work vehicle according to claim 2, wherein the load is gradually reduced continuously. A hydraulic power steering mechanism is used to operate the steered wheels by the steering wheel,
The work vehicle according to claim 1, wherein the control section changes the operating load of the steering wheel by controlling a hydraulic circuit of the hydraulic power steering mechanism. An electric power steering mechanism using an electric motor is used to operate the steered wheels by the steering wheel,
The work vehicle according to claim 1, wherein the control unit changes the operating load of the steering wheel by controlling the electric power steering mechanism.

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