Work vehicles

Abstract

To easily perform automatic steering in backing.SOLUTION: A work vehicle includes: a vehicle body; a travelling device; a steering wheel, a positioning device; a command switch; a steering changeover switch; a control device for issuing a command for automatic steering so that the vehicle body advances or backs in a direction opposite to the advancement along a scheduled travelling line corresponding to a travelling reference line when the automatic steering is started by the steering changeover switch; an operation member for performing an operation to switch advancing and backing of the vehicle body in both manual steering and automatic steering; a backing detection device for detecting backing of the vehicle body on the basis of the rotation direction of the travelling device; a work device provided in the rear part of the vehicle body; and a lifting and lowering device for lifting and lowering the work vehicle. When it is determined that the vehicle body is backing by the detection information by the backing detection device in a period from the time when the start of automatic steering is commanded by the steering changeover switch, and to the time when the automatic steering is finished, the control device performs automatic steering so that the vehicle body travels while backing along the scheduled travelling line.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a work vehicle such as a tractor. [Background technology]

[0002] Patent Document 1 discloses a conventional agricultural work machine. The agricultural work machine in Patent Document 1 includes a traveling machine body that can switch between manual traveling using manual steering and automatic traveling using automatic steering along a set traveling line that is set parallel to a traveling reference line, and a selector switch that can switch between manual traveling and automatic traveling. In addition, the agricultural work machine sets the start point of the traveling reference line after pressing the right instruction button while traveling along a ridge, and sets the end point of the traveling reference line by pressing the left instruction button while traveling. In other words, the traveling reference line is set before automatic steering. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2017-123803 Summary of the Invention [Problem to be solved by the invention]

[0004] The agricultural work machine of Patent Document 1 can easily perform automatic travel by switching from manual travel to automatic travel using a selector switch. However, the reality is that no consideration has been given to automatic travel while reversing agricultural work machines.

[0005] SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide a work vehicle that can easily perform automatic steering when reversing. [Means for solving the problem]

[0006] The technical means of the present invention for solving this technical problem is characterized by the following points.

[0007] The work vehicle includes a vehicle body, a working device provided on the vehicle body, a steering handle for steering the vehicle body, a positioning device capable of detecting the position of the vehicle body, a command switch for setting the position of the vehicle body detected by the positioning device as a travel reference line, a steering changeover switch for switching between starting and ending automatic steering separate from manual steering by the steering handle, and a steering changeover switch for controlling the vehicle body to move forward along a planned travel line corresponding to the travel reference line or to move backward in the opposite direction to the forward travel when the automatic steering is started by the steering changeover switch. a control device that issues an instruction for automatic steering; an operating member that switches between forward and reverse movement of the vehicle body in both the manual steering and the automatic steering; a reverse movement detection device that detects reverse movement of the vehicle body; and an alarm device that notifies that the vehicle body is approaching a predetermined position, wherein the control device executes automatic steering so that the vehicle body travels in reverse along the planned travel line when the start of automatic steering is instructed by the steering changeover switch and it is determined that the vehicle body is traveling in reverse based on detection information by the reverse movement detection device during the period from when the start of automatic steering is instructed by the steering changeover switch until the automatic steering is ended, When the vehicle body is traveling forward and then backward between the start and end of the automatic steering, The notification device notifies the start position of the automatic steering. a start position of the planned travel line along which the vehicle body is traveling while moving backward; The vehicle is notified that the vehicle body has approached the start corresponding position corresponding to the start corresponding position.

[0008] The control device sets the start corresponding position to a position shifted in the width direction of the vehicle body from the start position of the automatic steering when the steering changeover switch is switched to start the automatic steering.

[0009] The work vehicle is equipped with a steering shaft that rotatably supports the steering handle, and a correction switch that is arranged on the side of the steering shaft and that sets a correction amount, and the control device changes the deviation between the position of the vehicle body detected by the positioning device and the planned driving line by the correction amount set by the correction switch, and performs the automatic steering based on the changed deviation.

[0010] The correction switch is disposed on one side of the steering shaft, and the steering changeover switch is disposed on the other side of the steering shaft.

[0011] The correction switch is disposed on one side of the steering shaft, and the operating member is disposed on the other side of the steering shaft.

[0012] The work vehicle is a lifting device capable of lifting and lowering the working device; an auto-up device that raises the lifting device when the vehicle body moves backward; and, Equipped with the control device raises the lifting device by the auto-up device when the manual steering is performed and the vehicle body moves backward, The control device does not raise the lifting device by the auto-up device in the case of automatic steering in reverse. [Effects of the Invention]

[0013] According to the present invention, automatic steering can be easily performed when reversing. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 2 is a diagram showing the configuration and control block diagram of a tractor. [Figure 2] FIG. 2 is an explanatory diagram illustrating automatic steering. [Figure 3A] FIG. 10 is an explanatory diagram illustrating a correction amount in a push switch. [Figure 3B] FIG. 10 is an explanatory diagram illustrating a correction amount in a slide switch. [Figure 4A] 4A and 4B are diagrams illustrating a first correction unit and a second correction unit in the push switch. [Figure 4B] 10A and 10B are diagrams illustrating a first correction unit and a second correction unit in the slide switch. [Figure 5A] This shows the state when the calculated vehicle body position is shifted to the right while driving straight under automatic steering. [Figure 5B] This shows the state when the calculated vehicle body position is shifted to the left while driving straight under automatic steering. [Figure 6] This is a view of the cover in front of the driver's seat as seen from the driver's seat side. [Figure 7] FIG. 2 is an explanatory diagram illustrating automatic steering. [Figure 8] FIG. [Figure 9] 10 is an example of a planned driving line when driving while repeatedly going straight and backward. [Figure 10] 10 is an example of a farm field screen M1. [Figure 11] FIG. 1 is an overall view of a tractor. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0016] Fig. 11 is a side view showing one embodiment of the work vehicle 1, and Fig. 11 is a plan view showing one embodiment of the work vehicle 1. In this embodiment, the work vehicle 1 is a tractor. However, the work vehicle 1 is not limited to a tractor, and may be an agricultural machine (agricultural vehicle) such as a combine harvester or transplanter, or a construction machine (construction vehicle) such as a loader work machine.

[0017] In the following description, the front side of the driver seated in the driver's seat 10 of the tractor (work vehicle) 1 (the direction of arrow A1 in FIG. 11) will be referred to as the front, the rear side of the driver (the direction of arrow A2 in FIG. 11) will be referred to as the rear, the left side of the driver as the left side, and the right side of the driver as the right side. In addition, the horizontal direction that is perpendicular to the fore-and-aft direction of the work vehicle 1 will be referred to as the vehicle body width direction.

[0018] As shown in FIG. 11, the tractor 1 includes a body 3, a prime mover 4, and a transmission 5. The body 3 has a traveling device 7 and is capable of traveling. The traveling device 7 is a device having front wheels 7F and rear wheels 7R. The front wheels 7F may be of either a tire type or a crawler type. The rear wheels 7R may also be of either a tire type or a crawler type.

[0019] The prime mover 4 is a diesel engine, an electric motor, or the like, and in this embodiment is configured as a diesel engine. The transmission 5 is capable of switching the propulsive force of the traveling device 7 by changing gears, and is also capable of switching the traveling device 7 between forward and reverse. A driver's seat 10 is provided on the vehicle body 3.

[0020] Furthermore, a coupling section including a lifting device 8 is provided at the rear of the vehicle body 3. A working device can be attached and detached to the coupling section. By coupling the working device to the coupling section, the working device can be towed by the vehicle body 3. The working devices include a tilling device for tilling, a fertilizer spreading device for spreading fertilizer, a pesticide spreading device for spreading pesticide, a harvesting device for harvesting, a reaping device for reaping grass and the like, a spreading device for spreading grass and the like, a grass collecting device for collecting grass and the like, a shaping device for shaping grass and the like, and the like.

[0021] As shown in Figure 1, the transmission 5 includes a main shaft (propeller shaft) 5a, a main transmission section 5b, an auxiliary transmission section 5c, a shuttle section 5d, a PTO power transmission section 5e, and a front transmission section 5f. The propeller shaft 5a is rotatably supported in a housing case (transmission case) of the transmission 5, and power is transmitted to the propeller shaft 5a from the crankshaft of the engine 4. The main transmission section 5b has multiple gears and a shifter that changes the connections of the gears. The main transmission section 5b changes and outputs (shifts) the rotation input from the propeller shaft 5a by appropriately changing the connections (meshing) of the multiple gears using the shifter.

[0022] Similar to the main transmission unit 5b, the sub-transmission unit 5c has a plurality of gears and a shifter for changing the connection of the gears. The sub-transmission unit 5c changes and outputs (shifts) the rotation input from the main transmission unit 5b by appropriately changing the connection (meshing) of the plurality of gears with the shifter.

[0023] The shuttle unit 5d has a shuttle shaft 12 and a forward / reverse switching unit 13. Power output from the sub-transmission unit 5c is transmitted to the shuttle shaft 12 via gears or the like. The forward / reverse switching unit 13 is composed of, for example, a hydraulic clutch or the like, and switches the rotation direction of the shuttle shaft 12, i.e., the forward and reverse movement of the tractor 1, by engaging and disengaging the hydraulic clutch. The shuttle shaft 12 is connected to a rear wheel differential device 20R. The rear wheel differential device 20R rotatably supports a rear axle 21R to which the rear wheels 7R are attached.

[0024] The PTO power transmission section 5e has a PTO propeller shaft 14 and a PTO clutch 15. The PTO propeller shaft 14 is rotatably supported and can transmit power from the propeller shaft 5a. The PTO propeller shaft 14 is connected to a PTO shaft 16 via gears or the like. The PTO clutch 15 is composed of, for example, a hydraulic clutch, and by engaging and disengaging the hydraulic clutch, the state switches between transmitting the power of the propeller shaft 5a to the PTO propeller shaft 14 and not transmitting the power of the propeller shaft 5a to the PTO propeller shaft 14.

[0025] The front transmission unit 5f has a first clutch 17 and a second clutch 18. The first clutch 17 and the second clutch 18 can transmit power from the propeller shaft 5a, for example, power from the shuttle shaft 12 is transmitted via gears and transmission shafts. The power from the first clutch 17 and the second clutch 18 can be transmitted to the front axle 21F via a front transmission shaft 22. Specifically, the front transmission shaft 22 is connected to a front wheel differential device 20F, and the front wheel differential device 20F rotatably supports the front axle 21F to which the front wheels 7F are attached.

[0026] The first clutch 17 and the second clutch 18 are configured with hydraulic clutches or the like. An oil passage is connected to the first clutch 17, and the oil passage is connected to a first operating valve 25 to which hydraulic oil discharged from a hydraulic pump 33 is supplied. The first clutch 17 is switched between an engaged state and a disengaged state depending on the opening degree of the first operating valve 25. An oil passage is connected to the second clutch 18, and the oil passage is connected to a second operating valve 26. The second clutch 18 is switched between an engaged state and a disengaged state depending on the opening degree of the second operating valve 26. The first operating valve 25 and the second operating valve 26 are, for example, two-position switching valves with solenoid valves, and are switched between the engaged state and the disengaged state by energizing or deenergizing the solenoid of the solenoid valve.

[0027] When the first clutch 17 is disengaged and the second clutch 18 is engaged, the power of the shuttle shaft 12 is transmitted to the front wheels 7F via the second clutch 18. As a result, the front wheels 7F and rear wheels 7R are driven by power, resulting in four-wheel drive (4WD), and the rotational speeds of the front wheels 7F and rear wheels 7R are approximately the same (4WD constant speed state). On the other hand, when the first clutch 17 is engaged and the second clutch 18 is disengaged, the vehicle is in four-wheel drive, and the rotational speed of the front wheels 7F is faster than the rotational speed of the rear wheels 7R (4WD accelerated speed state). Furthermore, when the first clutch 17 and the second clutch 18 are disengaged, the power of the shuttle shaft 12 is not transmitted to the front wheels 7F, resulting in two-wheel drive (2WD) in which the rear wheels 7R are driven by power.

[0028] As shown in FIG. 8, the lifting device 8 has a lift arm 8a, a lower link 8b, a top link 8c, a lift rod 8d, and a lift cylinder 8e. The front end of the lift arm 8a is supported at the upper rear part of a case (transmission case) that houses the transmission 5 so that it can swing upward or downward. The lift arm 8a swings (lifts up and down) when driven by the lift cylinder 8e. The lift cylinder 8e is made up of a hydraulic cylinder. The lift cylinder 8e is connected to a hydraulic pump 33 via a control valve 29. The control valve 29 is an electromagnetic valve or the like, and extends and retracts the lift cylinder 8e.

[0029] The front end of the lower link 8b is supported on the rear lower part of the transmission 5 so as to be swingable upward or downward. The front end of the top link 8c is supported on the rear part of the transmission 5, above the lower link 8b, so as to be swingable upward or downward. The lift rod 8d connects the lift arm 8a to the lower link 8b. The working device 2 is connected to the rear part of the lower link 8b and the rear part of the top link 8c. When the lift cylinder 8e is driven (extends and retracts), the lift arm 8a rises and lowers, and the lower link 8b, which is connected to the lift arm 8a via the lift rod 8d, rises and lowers. As a result, the working device 2 swings upward or downward (lifts and lowers) around the front part of the lower link 8b as a fulcrum. The tractor 1 also has an auto-lift device that raises the lifting device 8 when the vehicle body 3 moves backward. In this embodiment, the auto-lift device includes the lift cylinder 8e and a control valve 29.

[0030] The tractor 1 is equipped with a positioning device 40. The positioning device 40 can detect its own position (positioning information including latitude and longitude) using a satellite positioning system (positioning satellite) such as D-GPS, GPS, GLONASS, Beidou, Galileo, or Michibiki. That is, the positioning device 40 receives satellite signals (position of the positioning satellite, transmission time, correction information, etc.) transmitted from the positioning satellites and detects its position (e.g., latitude and longitude) based on the satellite signals. The positioning device 40 includes a receiving device 41 and an inertial measurement unit (IMU) 42. The receiving device 41 has an antenna and the like and receives satellite signals transmitted from the positioning satellites, and is attached to the vehicle body 3 separately from the IMU 42. In this embodiment, the receiving device 41 is attached to a ROPs provided on the vehicle body 3. Note that the attachment location of the receiving device 41 is not limited to that described in the embodiment.

[0031] The inertial measurement unit 42 has an acceleration sensor that detects acceleration, a gyro sensor that detects angular velocity, etc. The inertial measurement unit 42 is provided on the vehicle body 3, for example, below the driver's seat 10, and can detect the roll angle, pitch angle, yaw angle, etc. of the vehicle body 3.

[0032] As shown in Fig. 1, the tractor 1 is equipped with a steering device 11. The steering device 11 is a device capable of performing manual steering, in which the vehicle body 3 is steered by operation by the driver, and automatic steering, in which the vehicle body 3 is steered automatically without operation by the driver.

[0033] The steering device 11 has a steering handle (steering wheel) 30 and a steering shaft (rotation shaft) 31 that rotatably supports the steering handle 30. The steering device 11 also has an assist mechanism (power steering device) 32. The assist mechanism 32 assists the rotation of the steering shaft 31 (steering handle 30) by hydraulic pressure or the like. The assist mechanism 32 includes a hydraulic pump 33, a control valve 34 to which hydraulic oil discharged from the hydraulic pump 33 is supplied, and a steering cylinder 35 that is operated by the control valve 34. The control valve 34 is, for example, a three-position switching valve that can be switched by movement of a spool or the like, and switches depending on the steering direction (rotation direction) of the steering shaft 31. The steering cylinder 35 is connected to an arm (knuckle arm) 36 that changes the direction of the front wheels 7F.

[0034] Therefore, when the driver grips the steering wheel 30 and turns it in one direction or the other, the switching position and opening of the control valve 34 are switched in accordance with the direction of rotation of the steering wheel 30, and the steering cylinder 35 expands or contracts to the left or right according to the switching position and opening of the control valve 34, thereby changing the steering direction of the front wheels 7F. In other words, the traveling direction of the vehicle body 3 can be changed to the left or right by manually steering the steering wheel 30.

[0035] Next, automatic steering will be described.

[0036] As shown in Figure 2, when performing automatic steering, a driving reference line L1 is first set before automatic steering is performed. After setting the driving reference line L1, automatic steering can be performed by setting a planned driving line L2 that is parallel to the driving reference line L1. In automatic steering, the tractor 1 (vehicle body 3) is automatically steered in the direction of travel so that the vehicle position measured by the positioning device 40 matches the planned driving line L2.

[0037] Specifically, before automatic steering is performed, the tractor 1 (body 3) is moved to a predetermined position in the field (S1), and when the driver operates the steering selector switch 52 provided on the tractor 1 at the predetermined position (S2), the body position measured by the positioning device 40 is set as the start point P10 of the traveling reference line L1 (S3). Furthermore, the tractor 1 (body 3) is moved from the start point P10 of the traveling reference line L1 (S4), and when the driver operates the steering selector switch 52 at the predetermined position (S5), the body position measured by the positioning device 40 is set as the end point P11 of the traveling reference line L1 (S6). Therefore, a straight line connecting the start point P10 and the end point P11 is set as the traveling reference line L1.

[0038] After the travel reference line L1 is set (after S6), for example, if the tractor 1 (body 3) is moved to a location different from the location where the travel reference line L1 was set (S7), and the driver operates the steering selector switch 52 (S8), a planned travel line L2, which is a straight line parallel to the travel reference line L1, is set (S9). After the planned travel line L2 is set, automatic steering is initiated, and the traveling direction of the tractor 1 (body 3) is changed to align with the planned travel line L2. For example, if the current body position is on the left side of the planned travel line L2, the front wheels 7F are steered to the right, and if the current body position is on the right side of the planned travel line L2, the front wheels 7F are steered to the left. Note that during automatic steering, the travel speed (vehicle speed) of the tractor 1 (body 3) can be changed by the driver manually changing the amount of operation of an accelerator member (accelerator pedal, accelerator lever) provided on the tractor 1 or by changing the gear position of the transmission 5.

[0039] Furthermore, after automatic steering has started, the driver can end automatic steering by operating the steering selector switch 52 at any point. That is, the end point of the planned traveling line L2 can be set by ending automatic steering by operating the steering selector switch 52. In other words, the length from the start point to the end point of the planned traveling line L2 can be set longer or shorter than the traveling reference line L1. In other words, the planned traveling line L2 is not associated with the length of the traveling reference line L1, and the planned traveling line L2 allows the vehicle to travel a distance longer than the length of the traveling reference line L1 while being automatically steered.

[0040] As shown in FIG. 1, the steering device 11 has an automatic steering mechanism 37. The automatic steering mechanism 37 is a mechanism that automatically steers the vehicle body 3, and automatically steers the vehicle body 3 based on the position of the vehicle body 3 (vehicle body position) detected by the positioning device 40. The automatic steering mechanism 37 includes a steering motor 38 and a gear mechanism 39. The steering motor 38 is a motor that can control the rotation direction, rotation speed, rotation angle, etc. based on the vehicle body position. The gear mechanism 39 includes a gear that is provided on the steering shaft 31 and rotates together with the steering shaft 31, and a gear that is provided on the rotation shaft of the steering motor 38 and rotates together with the rotation shaft. When the rotation shaft of the steering motor 38 rotates, the steering shaft 31 automatically rotates (turns) via the gear mechanism 39, and the steering direction of the front wheels 7F can be changed so that the vehicle body position coincides with the intended traveling line L2.

[0041] As shown in Fig. 1, the tractor 1 is equipped with a display device 45. The display device 45 is a device capable of displaying various information related to the tractor 1, and is capable of displaying at least driving information of the tractor 1. The display device 45 is provided in front of the driver's seat 10.

[0042] As shown in Fig. 1, the tractor 1 is equipped with a setting switch 51. The setting switch 51 is a switch that switches to a setting mode in which at least settings before the start of automatic steering are made. The setting mode is a mode in which various settings related to automatic steering are made before the start of automatic steering, such as a mode in which the start point and end point of the driving reference line L1 are set.

[0043] The setting switch 51 can be switched between ON and OFF, and when ON it outputs a signal indicating that the setting mode is enabled, and when OFF it outputs a signal indicating that the setting mode is disabled. Furthermore, when the setting switch 51 is ON it outputs a signal indicating that the setting mode is enabled to the display device 45, and when OFF it outputs a signal indicating that the setting mode is disabled to the display device 45.

[0044] The tractor 1 is equipped with a steering selector switch 52. The steering selector switch 52 is a switch that switches between starting and ending automatic steering. Specifically, the steering selector switch 52 can be switched from a neutral position to up, down, forward, or backward, and outputs a command to start automatic steering when the steering selector switch 52 is switched from the neutral position to down while the setting mode is enabled, and outputs a command to end automatic steering when the steering selector switch 52 is switched from the neutral position to up while the setting mode is enabled. Furthermore, when the steering selector switch 52 is switched from the neutral position to backward while the setting mode is enabled, the steering selector switch 52 outputs a command to set the current vehicle body position to the start point P10 of the driving reference line L1, and when the steering selector switch 52 is switched from the neutral position to forward while the setting mode is enabled, the steering selector switch 52 outputs a command to set the current vehicle body position to the end point P11 of the driving reference line L1. That is, the steering changeover switch 52 also serves as a reference line setting switch (command switch) that sets the start position (start point P10) and end position (end point P11) of the driving reference line L1. Note that the steering changeover switch 52, which switches between starting and ending automatic steering, may be configured as a separate switch from the reference line setting switch (command switch).

[0045] The tractor 1 is equipped with a correction switch 53. The correction switch 53 is a switch that corrects the vehicle body position (latitude, longitude) measured by the positioning device 40. In other words, the correction switch 53 is a switch that corrects the vehicle body position (referred to as a calculated vehicle body position) calculated using satellite signals (position of the positioning satellite, transmission time, correction information, etc.) and measurement information (acceleration, angular velocity) measured by the inertial measurement unit 42.

[0046] The correction switch 53 is configured as a push switch that can be pressed or a slide switch that can be slid. Below, the cases where the correction switch 53 is a push switch and a slide switch will be described.

[0047] If the correction switch 53 is a push switch, the amount of correction is set based on the number of times the push switch is operated. The amount of correction is determined by the formula: Correction Amount = Number of Operations x Correction Amount per Operation. For example, as shown in FIG. 3A, the amount of correction increases by several centimeters or several tens of centimeters each time the push switch is operated. The number of times the push switch is operated is input to the first control device 60A, which sets (calculates) the amount of correction based on the number of operations.

[0048] Furthermore, when the correction switch 53 is a slide switch, the correction amount is set based on the operation amount (displacement amount) of the slide switch. For example, the correction amount is determined by the correction amount = displacement amount from a predetermined position. For example, as shown in FIG. 3B, the correction amount increases by several centimeters or several tens of centimeters for every 5 mm increase in the displacement amount of the slide switch. The operation amount (displacement amount) of the slide switch is input to the first control device 60A, which sets (calculates) the correction amount based on the displacement amount. Note that the method of increasing the correction amount and the rate of increase are not limited to the above-mentioned numerical values.

[0049] 4A and 4B, the correction switch 53 has a first correction unit 53A and a second correction unit 53B. The first correction unit 53A is a unit that issues a command to correct the vehicle body position corresponding to one side in the width direction of the vehicle body 3, i.e., the left side. The second correction unit 53B is a unit that issues a command to correct the vehicle body position corresponding to the other side in the width direction of the vehicle body 3, i.e., the right side.

[0050] As shown in FIG. 4A, when the correction switch 53 is a push switch, the first correction unit 53A and the second correction unit 53B are ON / OFF switches that automatically return to their original state each time they are operated. The switch constituting the first correction unit 53A and the switch constituting the second correction unit 53B are integrated. Note that the switch constituting the first correction unit 53A and the switch constituting the second correction unit 53B may be disposed apart from each other. As shown in FIG. 3A, each time the first correction unit 53A is pressed, the correction amount corresponding to the left side of the vehicle body 3 (left correction amount) increases. Furthermore, each time the second correction unit 53B is pressed, the correction amount corresponding to the right side of the vehicle body 3 (right correction amount) increases.

[0051] As shown in FIG. 4B , when the correction switch 53 is a slide switch, the first correction unit 53A and the second correction unit 53B include a knob 55 that moves left or right along the longitudinal direction of the slot. When the correction switch 53 is a slide switch, the first correction unit 53A and the second correction unit 53B are spaced apart from each other in the width direction. As shown in FIG. 3B , when the knob 55 is gradually displaced leftward from a predetermined reference position, the left correction amount increases according to the amount of displacement. Similarly, when the knob 55 is gradually displaced rightward from a predetermined reference position, the right correction amount increases according to the amount of displacement. Note that, as shown in FIG. 4B , when the correction switch 53 is a slide switch, the first correction unit 53A and the second correction unit 53B may be integrally formed, the reference position of the knob 55 may be set to the center, and the left correction amount may be set when the knob 55 is moved leftward from the reference position, and the right correction amount may be set when the knob 55 is moved rightward from the middle position.

[0052] Next, the relationship between the correction amount (left correction amount, right correction amount) by the correction switch 53, the intended travel line L2, and the behavior (travel trajectory) of the tractor 1 (vehicle body 3) will be described.

[0053] FIG. 5A shows a state in which the calculated vehicle body position W1 deviates to the right while traveling straight during automatic steering. As shown in FIG. 5A, when automatic steering is initiated, if the actual position (actual position W2) of the tractor 1 (vehicle body 3) matches the calculated vehicle body position W1, and if the actual position W2 matches the planned traveling line L2, the tractor 1 travels along the planned traveling line L2. That is, in section P1 where there is no error in the positioning by the positioning device 40 and the vehicle body position (calculated vehicle body position W1) detected by the positioning device 40 is the same as the actual position W2, the tractor 1 travels along the planned traveling line L2. Note that if there is no error in the positioning by the positioning device 40 and no correction is made, the calculated vehicle body position W1 and the vehicle body position corrected with the correction amount (corrected vehicle body position) W3 are the same value. The corrected vehicle body position W3 is calculated vehicle body position W3 = calculated vehicle body position W1 - correction amount.

[0054] Here, suppose that near position P20, even though actual position W2 is not deviated from planned traveling line L2, various influences cause an error in the positioning of positioning device 40, causing vehicle body position W1 detected by positioning device 40 to deviate to the right from planned traveling line L2 (actual position W2), and deviation amount W4 is maintained. Then, tractor 1 determines that a deviation has occurred between calculated vehicle body position W1 and planned traveling line L2, and steers tractor 1 left to eliminate deviation amount W4 between calculated vehicle body position W1 and planned traveling line L2. Then, steering left shifts actual position W2 of tractor 1 toward planned traveling line L2. Suppose that the driver subsequently notices that tractor 1 is deviated from planned traveling line L2 and steers second correction unit 53B at position P21 to increase the right correction amount from zero. A right correction amount is added to the calculated vehicle body position W1, and the corrected vehicle body position (corrected vehicle body position) W3 can be made substantially the same as the actual position W2. In other words, by setting the right correction amount using the second correction unit 53B, the vehicle body position of the positioning device 40 can be corrected in a direction that eliminates the deviation amount W4 that occurred near position P20. Note that, as shown in position P21 in FIG. 5A, if the actual position W2 of the tractor 1 is away to the left from the intended travel line L2 after the vehicle body position is corrected, the tractor 1 is steered to the right, and the actual position W2 of the tractor 1 can be made to coincide with the intended travel line L2.

[0055] Figure 5B shows a state in which the calculated vehicle body position W1 deviates to the left while traveling straight during automatic steering. As shown in Figure 5B, when automatic steering is started, if the actual position W2 and the calculated vehicle body position W1 coincide and the actual position W2 and the planned traveling line L2 coincide, the tractor 1 travels along the planned traveling line L2, as in Figure 5A. That is, as in Figure 5A, in section P2 where there is no error in the positioning by the positioning device 40, the tractor 1 travels along the planned traveling line L2. Also, as in Figure 5A, the calculated vehicle body position W1 and the corrected vehicle body position W3 are the same value.

[0056] Here, suppose that at position P22, an error occurs in the positioning of the positioning device 40 due to various influences, causing the vehicle body position W1 detected by the positioning device 40 to deviate to the left with respect to the actual position W2, and the deviation amount W5 is maintained. The tractor 1 then steers the tractor 1 to the right to eliminate the deviation amount W5 between the calculated vehicle body position W1 and the intended travel line L2. Then, suppose that the driver notices that the tractor 1 has deviated from the intended travel line L2 and steers the first correction unit 53A at position P23 to increase the left correction amount from zero. This adds the left correction amount to the calculated vehicle body position W1, and the corrected vehicle body position (corrected vehicle body position) W3 can be made substantially equal to the actual position W2. In other words, by setting the left correction amount using the first correction unit 53A, the vehicle body position of the positioning device 40 can be corrected in a direction that eliminates the deviation amount W5 that occurred near position P22. Furthermore, as shown at position P23 in Figure 5B, if, after correcting the vehicle body position, the actual position W2 of the tractor 1 is away to the right from the planned driving line L2, the tractor 1 is steered to the left, and the actual position W2 of the tractor 1 can be aligned with the planned driving line L2.

[0057] Next, the setting switch 51 and the correction switch 53 will be described.

[0058] As shown in Fig. 6, the outer periphery of the steering shaft 31 is covered by a steering post 180. The outer periphery of the steering post 180 is covered by a cover 177. The cover 177 is provided in front of the driver's seat 10. The cover 177 includes a panel cover 178 and a column cover 179.

[0059] The panel cover 178 supports the display device 45. An upper plate portion 178a of the panel cover 178 is provided with a support portion 178e that supports the display device 45. The support portion 178e supports the display device 45 in front of the steering shaft 31 and below the steering handle 30. The upper plate portion 178a also has a mounting surface 178f to which the setting switch 51 and the correction switch 53 are attached. The mounting surface 178f is provided rearward of the support portion 178e and below the steering handle 30. The support portion 178e and the mounting surface 178f are continuous, with the support portion 178e located in front of the upper plate portion 178a and the mounting surface 178f located in rearward of the upper plate portion 178a. The setting switch 51 and the correction switch 53 are attached to the mounting surface 178f. As a result, the setting switch 51 and the correction switch 53 are arranged around the steering shaft 31.

[0060] A shuttle lever 181 protrudes from the left plate portion 178b of the panel cover 178. The shuttle lever 181 is a member that switches the traveling direction of the vehicle body 3. To explain in more detail, by operating (swinging) the shuttle lever 181 forward, the forward / reverse travel switching unit 13 enters a state in which it outputs forward power to the traveling device 7, and the traveling direction of the vehicle body 3 is switched to the forward direction. In addition, by operating (swinging) the shuttle lever 181 backward, the forward / reverse travel switching unit 13 enters a state in which it outputs reverse power to the traveling device 7, and the traveling direction of the vehicle body 3 is switched to the reverse direction. When the shuttle lever 181 is in the neutral position, no power is output to the traveling device 7.

[0061] The column cover 179 is disposed below the steering wheel 30 and covers the periphery of the upper part of the steering shaft 31. The column cover 179 is formed in a substantially rectangular tubular shape and protrudes upward from the mounting surface 178f of the panel cover 178. In other words, the mounting surface 178f is provided around the periphery of the column cover 179. Therefore, the setting switch 51 and the correction switch 53 attached to the mounting surface 178f are disposed around the periphery of the column cover 179.

[0062] Next, a detailed description will be given of the locations of the setting switch 51, steering changeover switch 52, and correction switch 53. As shown in Fig. 6, the setting switch 51, steering changeover switch 52, and correction switch 53 are arranged around the steering shaft 31.

[0063] The setting switch 51 is disposed on one side (left) of the steering shaft 31. The steering changeover switch 52 is disposed on one side (left) of the steering shaft 31. In this embodiment, the steering changeover switch 52 is configured as a swingable lever. The steering changeover switch 52 can swing around a base end provided on the steering shaft 31 side as a fulcrum. The base end of the steering changeover switch 52 is provided inside the column cover 179. The steering changeover switch 52 protrudes from one side (left) of the column cover 179.

[0064] The correction switch 53 is disposed on the other side (right side) of the steering shaft 31. More specifically, the correction switch 53 is disposed to the right and rear (diagonally rear right) of the steering shaft 31. In terms of its position relative to the column cover 179, the correction switch 53 is disposed to the right and rear (diagonally rear right) of the column cover 179. In terms of its position relative to the mounting surface 178f of the panel cover 178, the correction switch 53 is disposed at the rear right of the mounting surface 178f. By disposing the correction switch 53 at the rear of the inclined mounting surface 178f, a long distance can be secured between the correction switch 53 and the steering wheel 30. This more reliably prevents unintentional operation of the correction switch 53 and steering of the steering wheel 30.

[0065] As described above, the setting switch 51, steering changeover switch 52, and correction switch 53 are arranged around the steering shaft 31. In other words, the setting switch 51, steering changeover switch 52, and correction switch 53 are concentrated around the steering shaft 31. This allows the driver to clearly understand the location of each switch at a glance. In addition, the driver can operate each switch without changing his / her posture while remaining seated in the driver's seat 10. This improves operability and prevents erroneous operation. In addition, the harnesses (wiring) routed from each switch can be shortened.

[0066] It should be noted that the above-described switch arrangement may be reversed between left and right. That is, one side may be the left and the other side may be the right, or one side may be the right and the other side may be the left. Specifically, for example, the setting switch 51 and the steering changeover switch 52 may be arranged on the right side of the steering shaft 31, and the correction switch 53 may be arranged on the left side of the steering shaft 31.

[0067] As shown in Fig. 1, the tractor 1 is equipped with a plurality of control devices 60. The plurality of control devices 60 are devices that control the traveling system, the working system, calculate the vehicle body position, etc. of the tractor 1. The plurality of control devices 60 are a first control device 60A, a second control device 60B, and a third control device 60C.

[0068] The first control device 60A receives satellite signals (received information) received by the receiving device 41 and measurement information (acceleration, angular velocity, etc.) measured by the inertial measurement device 42, and calculates the vehicle body position based on the received information and the measurement information. For example, if the correction amount by the correction switch 53 is zero, i.e., if correction of the vehicle body position by the correction switch 53 is not instructed, the first control device 60A does not correct the calculated vehicle body position W1 calculated from the received information and the measurement information, and determines the calculated vehicle body position W1 as the vehicle body position to be used during automatic steering. On the other hand, if correction of the vehicle body position by the correction switch 53 is instructed, the first control device 60A sets the correction amount for the vehicle body position based on either the number of times the correction switch 53 is operated or the operation amount (displacement amount) of the correction switch 53, and determines the corrected vehicle body position W3 obtained by correcting the calculated vehicle body position W1 with the correction amount as the vehicle body position to be used during automatic steering.

[0069] The first control device 60A sets a control signal based on the vehicle body position (calculated vehicle body position W1, corrected vehicle body position W3) and the intended traveling line L2, and outputs the control signal to the second control device 60B. The second control device 60B has an automatic steering control unit 200. The automatic steering control unit 200 is composed of electric and electronic circuits provided in the second control device 60B, programs stored in a CPU, etc. The automatic steering control unit 200 controls the steering motor 38 of the automatic steering mechanism 37 based on the control signal output from the first control device 60A so that the vehicle body 3 travels along the intended traveling line L2.

[0070] 7, when the deviation between the vehicle body position and the planned travel line L2 is less than a threshold value, the automatic steering control unit 200 maintains the rotation angle of the rotation shaft of the steering motor 38. When the deviation between the vehicle body position and the planned travel line L2 is equal to or greater than the threshold value and the tractor 1 is located on the left side of the planned travel line L2, the automatic steering control unit 200 rotates the rotation shaft of the steering motor 38 so that the steering direction of the tractor 1 is to the right. When the deviation between the vehicle body position and the planned travel line L2 is equal to or greater than the threshold value and the tractor 1 is located on the right side of the planned travel line L2, the automatic steering control unit 200 rotates the rotation shaft of the steering motor 38 so that the steering direction of the tractor 1 is to the left. In the above-described embodiment, the steering angle of the steering device 11 is changed based on the deviation between the vehicle body position and the planned travel line L2. However, if the orientation of the planned travel line L2 differs from the orientation (vehicle body orientation) F1 of the direction of travel (travel direction) of the tractor 1 (vehicle body 3), that is, if the angle θg of the vehicle body orientation F1 with respect to the planned travel line L2 is equal to or greater than a threshold value, the automatic steering control unit 200 may set the steering angle so that the angle θg is zero (the vehicle body orientation F1 matches the orientation of the planned travel line L2). Furthermore, the automatic steering control unit 200 may set the final steering angle in automatic steering based on the steering angle calculated based on the deviation (position deviation) and the steering angle calculated based on the orientation (orientation deviation). The setting of the steering angle in automatic steering in the above-described embodiment is an example and is not limited thereto.

[0071] As described above, the control device 60 can automatically steer the tractor 1 (body 3).

[0072] The third control device 60C performs various controls related to the tractor 1. The third control device 60C can perform manual lift control, auto-up control, and the like. In manual lift control, the lift device 8 is raised and lowered based on the operation of a lift switch 101 connected to the third control device 60C. Specifically, the lift switch 101 is a three-position switch provided around the driver's seat 10. When the lift switch 101 is switched from the neutral position to one side, an up signal for raising the lift device 8 (lift arm 8a) is input to the third control device 60C. When the lift switch 101 is switched from the neutral position to the other side, a down signal for lowering the lift device 8 (lift arm 8a) is input to the third control device 60C. When the third control device 60C receives an up signal, it outputs a control signal to the control valve 29 to raise the lift device 8, and when it receives a down signal, it outputs a control signal to the control valve 29 to lower the lift device 8. That is, the third control device 60 can perform manual lift control to raise and lower the lift device 8 in response to manual operation of the lift switch 101.

[0073] Furthermore, the auto-up control is a control that automatically operates the lifting device 8 to raise the working implement 2 when the tractor 1 (body 3) moves backward. Specifically, a reverse movement detection device 102 that detects reverse movement is connected to the control device 60 such as the control device 60C. The reverse movement detection device 102 includes a sensor that detects the rotation of the front axle 21F, a sensor that detects the rotation of the rear axle 21R, and a sensor that detects the switching position of the shuttle lever 181. That is, the reverse movement detection device 102 detects the reverse movement of the tractor 1 (body 3) when the rotation direction of the front axle 21F and the rotation direction of the rear axle 21R correspond to the rotation direction corresponding to reverse movement, and when the switching position of the shuttle lever 181 is on the reverse side. When the reverse movement detection device 102 detects the reverse movement of the tractor 1 (body 3), the third control device 60C performs auto-up control that automatically raises the lifting device 8 by outputting a control signal to the control valve 29 of the auto-up device. The reverse movement detection device 102 described above is an example and is not limiting.

[0074] As described above, the control device 60C can perform controls related to the tractor 1, such as manual lifting control and auto-up control.

[0075] The tractor 1 can perform automatic steering while moving backward. FIG. 9 is a diagram showing forward automatic steering and reverse automatic steering of the tractor 1. As shown in FIG. 9, when performing automatic steering in a field H1, each time the steering selector switch 52 is operated to start automatic steering, a plurality of straight line segments SLn (n = 1, 2, 3, ...) of the intended travel line L2 are set. For example, when the steering selector switch 52 is operated at the start position ST1 and a command to start automatic steering is issued, the first straight line segment SL1 is set. Then, the automatic steering control unit 200 can perform automatic steering while moving the tractor 1 forward along the straight line segment SL1. When the steering selector switch 52 is operated at the end position EN1 and a command to end automatic steering is issued, automatic steering along the straight line segment SL1 can be ended. When working with the implement attached to the tractor 1, after automatic forward steering on the first straight section SL1 is completed, automatic reverse steering is performed without turning the tractor 1.

[0076] For example, when the steering selector switch 52 is operated at the start position ST2 and a command to start automatic steering is issued, a second straight section SL2 is set. Then, the control devices 60 (the second control device 60B and the third control device 60C) perform automatic steering while moving the tractor 1 backward along the straight section SL2. Specifically, when the start of automatic steering is initiated by the steering selector switch 52, the second control device 60B and the third control device 60C control the automatic steering so that the tractor 1 moves backward along the straight section SL2. Specifically, when a command to start automatic steering is issued by the steering selector switch 52, the third control device 60C determines whether the vehicle body 3 is moving backward based on detection information from the reverse movement detection device 102, and if the vehicle body 3 is moving backward, the third control device 60C disables the auto-up control and does not perform the auto-up control even if the reverse movement detection device 102 detects reverse movement. Furthermore, the automatic steering control section 200 of the second control device 60B performs automatic steering so that the tractor 1 travels backward along the straight section SL2. When the steering changeover switch 52 is operated at the end position EN2 to issue a command to end the automatic steering, the third control device 60 sets the auto-up control from disabled to enabled, enabling the auto-up control to be performed.

[0077] When the lift switch 101 is operated while the tractor 1 is being automatically steered while moving backward along the straight section SL2, the third control device 60C raises or lowers the lift device 8 in accordance with the operation of the lift switch 101. In other words, in the case of automatic steering during reverse, the third control device 60C performs lifting or lowering by operating the lift switch 101.

[0078] As shown in FIG. 1, the tractor 1 is equipped with an alarm device 80. The alarm device 80 is a device that issues an alarm when the tractor 1 (body 3) approaches the position where automatic steering ends. The alarm device 80 is a speaker, a lamp, or the like, and is provided near the driver's seat 10. Specifically, the alarm device 80 issues an alarm by outputting audio from the speaker, sounding a warning, turning on or flashing a lamp, or the like, that the body 3 is approaching a shift position that is shifted in the width direction of the body 3 from the position of the body 3 when automatic steering ended (the end position of automatic steering).

[0079] The relationship between the notification by the notification device 80, the end position of the automatic steering, and the shift position will be described in detail below.

[0080] If the end position of automatic steering is ENn, the end positions ENn of automatic steering for even-numbered straight line segments SLn (n=2, 4, 6, . . . ) are aligned on one side of the field (upper side of the paper in FIG. 9).

[0081] At one end position ENn, automatic steering ends at a skipped position, so the shift position is the (n+2)th end position ENn+2 (n=2, 4, 6, etc.) from the current end position ENn. For example, if the second end position EN2 is used as the reference, the shift position corresponds to the end position EN4. In other words, when the second end position EN2 is determined by the steering selector switch 52, the notification device 80 issues a notification when the tractor 1 approaches the shift position corresponding to the fourth end position EN4. For example, when the tractor 1 travels along the straight section SL4 and the tractor 1 approaches the fourth end position EN4 (shift position), the notification device 80 issues a notification. More specifically, when an automatic steering command is issued by the steering changeover switch 52 at the second end position EN2, the first control device 60A holds the detected position (vehicle body position) detected by the positioning device 40, and sets the shift position (end corresponding position) corresponding to the end position by adding the shift amount (shift distance) AD1 in the width direction of the vehicle body 3 to the held position (end position EN2).The notification device 80 issues a notification when, during manual steering, the distance difference between the vehicle body position detected by the positioning device 40 and the end corresponding position becomes equal to or less than a predetermined value.

[0082] Furthermore, the automatic steering end position ENn for odd-numbered straight line segments SLn (n = 1, 3, 5, etc.) is located on the other side of the field (the bottom side of the paper in Figure 9). The end corresponding position for the end position ENn on the other side is also the (n+2)th end position ENn+2 (n = 1, 3, 5, etc.) from the current end position ENn. For example, if the first end position EN1 is used as the reference, the end corresponding position corresponds to end position EN3.

[0083] In this case, when the first end position EN1 is determined by the steering selector switch 52, the notification device 80 issues a notification when the tractor 1 approaches an end corresponding position corresponding to the third end position EN3. More specifically, when an automatic steering command is issued by the steering selector switch 52 at the first end position EN1, the first control device 60A holds the detected position (vehicle body position) detected by the positioning device 40 and calculates the end corresponding position by adding the shift amount (shift distance) AD1 in the width direction of the vehicle body 3 to the held position (end position EN1). The notification device 80 issues a notification when the distance difference between the vehicle body position detected by the positioning device 40 and the end corresponding position becomes equal to or less than a predetermined value during manual steering.

[0084] It is preferable that the interval between notifications by the notification device 80 be changed according to the difference in distance between the tractor 1 and the end corresponding position. For example, when the notification device 80 outputs a sound, the output interval of the sound indicating approach is shortened when the difference in distance is short, and lengthened when the difference in distance is long.

[0085] The tractor 1 is equipped with a memory device 81. The memory device 81 is a device that stores the position of the tractor 1 (start position STn, end position ENn) when the steering selector switch 52 is used to switch to start or end automatic steering, that is, the detected position (vehicle body position) detected by the positioning device 40. The memory device 81 may be built into the control device 60 or the display device 45, or may be a separate device.

[0086] The display device 45 displays the start position STn and end position ENn stored in the storage device 81 on a field map MP1 showing the work site of the tractor 1, i.e., the field. As shown in FIG. 10, when a predetermined operation is performed on the display device 45, the display device 45 displays a field screen M1. The field screen M1 displays the current field H1 where the tractor 1 is working, as well as the detected position SP1 (traveling line L10) detected by the positioning device 40. The display device 45 also references the storage device 81 to display the start position STn and end position ENn in the current field H1. For example, on the field screen M1, the display device 45 displays a symbol 83a indicating the start position STn and a symbol 83b indicating the end position ENn, superimposed on the field map MP1.

[0087] In the above-described embodiment, an alert was given when the vehicle approached the start corresponding position corresponding to the start position STn of automatic steering and the end corresponding position corresponding to the end position ENn of automatic steering, but an alert may also be given when the vehicle approached either the start corresponding position or the end corresponding position.

[0088] The work vehicle 1 is equipped with a vehicle body 3, a steering wheel 30 for steering the vehicle body 3, a positioning device 40 capable of detecting the position of the vehicle body 3, a command switch for setting the position of the vehicle body 3 detected by the positioning device 40 to a traveling reference line L1, a steering changeover switch 52 for switching between starting and ending automatic steering separate from manual steering by the steering wheel 30, and a control device 60 for issuing a command for automatic reverse steering so that the vehicle body 3 moves backward along an intended traveling line L2 corresponding to the traveling reference line L1 when automatic steering is started by the steering changeover switch 52. This allows the vehicle body 3 to easily move backward along the intended traveling line L2 during automatic steering. In other words, automatic steering when moving backward can be easily performed.

[0089] The work vehicle 1 is equipped with a working device 2 provided at the rear of the vehicle body 3, a lifting device 8 that can raise and lower the working device 2, and an auto-up device that raises the lifting device 8 when the vehicle body 3 is reversed, and the control device 60 raises the lifting device 8 using the auto-up device when the vehicle body 3 is manually steered and reversed, but does not raise the lifting device 8 using the auto-up device when reversed and automatically steered. As a result, when the vehicle body 3 is reversed while manually steering, the lifting device 8 can be automatically raised, while when the vehicle body is reversed while automatically steering, the lifting device 8 can be stopped and work can be performed using the working device 2.

[0090] The work vehicle 1 is equipped with a lift switch 101 that operates the lifting device 8 to lift or lower the vehicle, and in the case of automatic steering in reverse, the control device 60 performs lifting or lowering by operating the lift switch 101. In this way, when the vehicle body is reversed while performing automatic steering, the work device 2 can be raised or lowered by operating the lift switch 101.

[0091] When the vehicle body 3 has traveled a predetermined distance since starting to move backward, the control device 60 holds the end position of the vehicle body 3 when the steering changeover switch 52 is switched to end automatic steering. This makes it possible to know the end position when automatic steering ends, and to align the end position of work while moving backward (end position of automatic steering).

[0092] The work vehicle 1 is equipped with a notification device 80 that notifies that the vehicle body 3 is approaching a shift position that is shifted in the width direction of the vehicle body 3 from the end position of the vehicle body 3. With this, when the vehicle body 3 is moving backward, the notification device 80 can identify at least the end position of the previous automatic steering.

[0093] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0094] 1 Work vehicle 2. Work equipment 3. Body 8 Lifting device 30 Steering wheel 60 Control device 60C Third control device L1 Driving reference line

Claims

1. The car body and a working device provided on the vehicle body; a steering handle for steering the vehicle body; a positioning device capable of detecting the position of the vehicle body; a command switch for setting the position of the vehicle body detected by the positioning device to a traveling reference line; a steering changeover switch for switching between starting and ending automatic steering separate from manual steering by the steering handle; a control device that issues an automatic steering command when the automatic steering is started by the steering changeover switch so that the vehicle body moves forward along a planned travel line corresponding to the travel reference line, or moves backward in a direction opposite to the forward travel; an operating member for switching between forward and reverse movement of the vehicle body in both the manual steering and the automatic steering; a reverse movement detection device that detects the reverse movement of the vehicle body; an alarm device that notifies that the vehicle body is approaching a predetermined position; Equipped with When the control device determines that the vehicle body is moving backward based on detection information from the reverse movement detection device during the period from when the start of automatic steering is commanded by the steering changeover switch until the automatic steering is ended, the control device executes automatic steering so that the vehicle body travels while moving backward along the planned travel line, When the vehicle body travels forward and then in reverse between the start and end of the automatic steering, the notification device notifies the work vehicle that the vehicle body is approaching a start corresponding position, which is the start position of the automatic steering and corresponds to the start position of the planned travel line along which the vehicle body is traveling in reverse.

2. 2. The work vehicle according to claim 1, wherein the control device sets the start corresponding position to a position shifted in the width direction of the vehicle body from the start position of the automatic steering when the steering changeover switch is switched to start the automatic steering.

3. a steering shaft that rotatably supports the steering handle; a correction switch disposed on a side of the steering shaft for setting a correction amount; Equipped with 3. The work vehicle according to claim 1, wherein the control device changes the deviation between the position of the vehicle body detected by the positioning device and the planned driving line by the correction amount set by the correction switch, and performs the automatic steering based on the changed deviation.

4. The correction switch is disposed on one side of the steering shaft, 4. The work vehicle according to claim 3, wherein the steering changeover switch is disposed on the other side of the steering shaft.

5. The correction switch is disposed on one side of the steering shaft, 5. The work vehicle according to claim 3, wherein the operating member is disposed on the other side of the steering shaft.

6. a lifting device capable of lifting and lowering the working device; an auto-up device that raises the lifting device when the vehicle body moves backward; Equipped with the control device raises the lifting device by the auto-up device when the manual steering is performed and the vehicle body moves backward, 6. The work vehicle according to claim 1, wherein the control device does not raise the lifting device by the auto-up device when the reverse automatic steering is being performed.

Images