Work vehicle

Abstract

To perform stably and safely automatic steering of a work vehicle (1) during a backward movement, the work vehicle (1) comprises: a vehicle body (3) that can travel forward and backward by either of manual steering through a steering handle (30) or automatic steering; a prime mover (4) provided on the vehicle body; a work device (2) supported by the vehicle body; a PTO shaft (16) for transmitting power of the prime mover to the work device; and a control device (60) for controlling drive of the PTO shaft and the automatic steering, wherein, when the PTO shaft is stopped, the control device permits the automatic steering in the vehicle body during a backward movement, and when the PTO shaft is driven, the control device prohibits the automatic steering in the vehicle body during a backward movement.

Description

Technical Field

[0001] The present invention relates to a work vehicle such as a tractor, for example.

Background Art

[0002] Conventionally, a work vehicle disclosed in Patent Document 1 is known. The work vehicle of Patent Document 1 includes a vehicle body capable of traveling forward and backward by either manual steering or automatic steering using a steering wheel, a PTO (Power Take Off) shaft that transmits the power of a prime mover provided on the vehicle body to a work device supported behind the vehicle body, and a control device that controls automatic steering and driving of the PTO shaft.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the work vehicle of Patent Document 1, when the vehicle travels backward by automatic steering in a state where the rotational speed of the PTO shaft is increased, depending on the operating state of the work device, it may become difficult to perform automatic steering stably, or there is a risk of endangering the driver looking backward from the driver's seat of the vehicle body.

[0005] Therefore, in view of the above problems, an object of the present invention is to perform automatic steering during backward travel of a work vehicle stably and safely.

Means for Solving the Problems

[0006] Technical means of the present invention for solving the above technical problems are characterized by the following points. A work vehicle according to an aspect of the present invention includes a vehicle body capable of traveling forward and backward, a prime mover provided on the vehicle body, a working device supported by the vehicle body, a PTO shaft for transmitting the power of the prime mover to the working device, a steering wheel for manually steering the vehicle body, an automatic steering mechanism including an actuator for automatically steering the vehicle body, a positioning device for positioning the position of the vehicle body, and automatic steering mechanism a control device that controls the automatic steering and detects the driving and stopping states of the PTO shaft. The control device can execute automatic steering to automatically steer the vehicle body by operating the automatic steering mechanism based on the position of the vehicle body measured by the positioning device and the travel reference line when the vehicle body is moving forward and backward and the vehicle speed is manually changed. When the PTO shaft is stopped, automatic steering during backward travel of the vehicle body is permitted, and when the start of the automatic steering is instructed, the automatic steering is executed. When the PTO shaft is driven, automatic steering during backward travel of the vehicle body is prohibited, and when the start of the automatic steering is instructed even if the automatic steering is not executed.

[0007] Also, in one aspect of the present invention, the work vehicle includes a PTO operation member for operating the drive of the PTO shaft, which can be switched from a neutral position to a drive position. When the PTO operation member is in the neutral position, the PTO shaft is stopped, and the control device permits automatic steering during backward travel of the vehicle body. When the PTO operation member is switched to the drive position, the control device prohibits automatic steering during backward travel of the vehicle body, and the PTO shaft becomes drivable.

[0008] Also, in one aspect of the present invention, the work vehicle is selfA setting switch that is operated to instruct the setting of a travel reference line serving as a reference for manual steering, and a steering switch that is operated to instruct the start and stop of automatic steering are provided. The control device sets a travel reference line based on the position of the vehicle body detected by a positioning device during the travel of the vehicle body by manual steering in response to the operation of the setting switch. When automatic steering during the reverse travel of the vehicle body is permitted, the control device starts automatic steering in response to the start operation of the steering switch, executes automatic steering based on the travel reference line and the position of the vehicle body detected by the positioning device, and stops automatic steering in response to the stop operation of the steering switch. When automatic steering during the reverse travel of the vehicle body is prohibited, the control device does not start or stop automatic steering in response to the operation of the steering switch.

[0009] Further, in one aspect of the present invention, the work vehicle includes a notification device that notifies that automatic steering during the reverse travel of the vehicle body is prohibited.

[0010] Further, in one aspect of the present invention, the notification device further notifies a guidance prompting to stop the PTO shaft. Furthermore, in one aspect of the present invention, the notification device performs the above notification when the start of automatic steering is instructed in the case where automatic steering during the reverse travel of the vehicle body is prohibited.

Advantages of the Invention

[0011] According to the present invention, automatic steering during the reverse travel of the work vehicle can be performed stably and safely.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Mode for Carrying Out the Invention

[0013] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0014] First, the appearance of the work vehicle 1 of this embodiment will be described. FIG. 12 is a side view of the work vehicle 1. The work vehicle 1 of this embodiment is a tractor. However, the work vehicle of the present invention is not limited to a tractor as shown in FIG. 12, and may be an agricultural machine (agricultural vehicle) such as a combine or a transplanter, or a construction machine (construction vehicle) such as a loader work machine.

[0015] Hereinafter, the front side (in the direction of arrow A1 in FIG. 12) of the driver sitting in the driver's seat 10 of the work vehicle 1 will be described as the front, the rear side (in the direction of arrow A2 in FIG. 12) of the driver as the rear, the left side of the driver as the left, and the right side of the driver as the right. Also, the horizontal direction, which is the direction orthogonal to the front-rear direction of the work vehicle 1, will be described as the vehicle body width direction.

[0016] As shown in FIG. 12, the work vehicle 1 includes a vehicle body 3, a prime mover 4, and a traveling device 75. The vehicle body 3 can travel back and forth by the traveling device 7. The traveling device 7 has front wheels 7F and rear wheels 7R. The front wheels 7F may be of the tire type or the crawler type. Also, the rear wheels 7R may be of the tire type or the crawler type. The prime mover 4 is composed of a diesel engine. As another example, the prime mover 4 may be composed of an electric motor or the like.

[0017] At the upper part of the vehicle body 3, a driver's seat 10 is provided. At the rear part of the vehicle body 3, a connecting part (not shown) including a lifting device 8 is provided. The working device 2 is detachable from the connecting part. By connecting the working device 2 to the connecting part, the working device 2 is supported behind the vehicle body 3, and the vehicle body 3 can tow the working device 2. The working device 2 is a tilling device for tilling, a fertilizer spraying device for spraying fertilizers, a pesticide spraying device for spraying pesticides, a harvesting device for harvesting, a mowing device for mowing 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.

[0018] In front of the driver's seat 10 of the vehicle body 3, an operation console 9F is provided. The operation console 9F is provided with operation parts such as a steering wheel 30, a lever, and a switch. On the left side of the driver's seat 10, an operation console 9L is provided, and on the right side, an operation console 9R is provided (see FIG. 7 described later). The operation consoles 9L and 9R are also provided with operation parts such as a lever and a switch, respectively.

[0019] Behind the driver's seat 10 of the vehicle body 3, a roll bar 6 is installed. The roll bar 6 is, for example, an example of a protection mechanism that protects the driver sitting on the driver's seat 10 when the work vehicle 1 overturns.

[0020] Next, the configuration of the work vehicle 1 will be described. FIG. 1 is a control block diagram of the work vehicle 1. The work vehicle 1 includes a transmission 5, differential devices 20F and 20R, a lifting device 8, a steering device 11, a control device 60, a positioning device 40, a display device 45, operation valves 25 to 29, and switches 23, 24, 50 to 54.

[0021] The transmission 5 can switch the driving force of the traveling device 7 by shifting gears, and can also switch between forward and reverse of the traveling device 7. The transmission 5 includes a propulsion shaft (main shaft) 5a, a main transmission section 5b, a sub-transmission section 5c, a shuttle section 5d, a PTO power transmission section 5e, and a front transmission section 5f. The propulsion shaft 5a is rotatably supported by the housing case (transmission case) of the transmission 5. Power from the crankshaft of the prime mover 4 is transmitted to the propulsion shaft 5a. The main transmission section 5b has a plurality of gears and a shifter for changing the connection of the gears. The main transmission section 5b changes and outputs (shifts) the rotation input from the propulsion shaft 5a by appropriately changing the connection (meshing) of the plurality of gears with the shifter.

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

[0023] The shuttle section 5d has a shuttle shaft 12 and a forward / reverse clutch 13. Power output from the sub-transmission section 5c is transmitted to the shuttle shaft 12 via gears and the like. The forward / reverse clutch 13 is composed of, for example, a hydraulic clutch. An oil passage is connected to the forward / reverse clutch 13, and an operating valve 28 is connected to the oil passage. The operating valve 28 is supplied with hydraulic oil discharged from a hydraulic pump 33. The forward / reverse clutch 13 switches between a connected state and a disconnected state according to the opening degree of the operating valve 28. The operating valve 28 is, for example, a two-position switching valve with a solenoid valve. By exciting or demagnetizing the solenoid of the solenoid valve of the operating valve 28, the forward / reverse clutch 13 switches between the connected state and the disconnected state.

[0024] When the forward / reverse clutch 13 switches between the connected state and the disconnected state, the rotation direction of the shuttle shaft 12 is switched. The shuttle shaft 12 is connected to the 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.

[0025] The PTO (Power Take Off) power transmission unit 5e has a PTO propulsion shaft 14 and a PTO clutch 15. The PTO propulsion shaft 14 is rotatably supported and is capable of transmitting power from the propulsion shaft 5a. The PTO propulsion shaft 14 is connected to a PTO shaft 16 via gears or the like.

[0026] The PTO clutch 15 is configured, for example, by a hydraulic clutch. An oil passage is connected to the PTO clutch 15, and an actuating valve 27 is connected to the oil passage. Hydraulic oil discharged from a hydraulic pump 33 is supplied to the actuating valve 27. The PTO clutch 15 is switched between an engaged state and a disengaged state depending on the opening of the actuating valve 27. The actuating valve 27 is, for example, a two-position switching valve with a solenoid valve. The PTO clutch 15 is switched between an engaged state and a disengaged state by energizing or de-energizing the solenoid of the solenoid valve of the actuating valve 27.

[0027] By switching the PTO clutch 15 between an engaged state and a disengaged state, the state switches between a state in which the power of the propeller shaft 5a is transmitted to the PTO propeller shaft 14 and a state in which the power of the propeller shaft 5a is not transmitted to the PTO propeller shaft 14. The power of the prime mover 4 is transmitted to the PTO shaft 16 via the propeller shaft 5a, the PTO clutch 15, and the PTO propeller shaft 14, and the PTO shaft 16 is rotated. operation The driving force of the PTO shaft 16 is is made This is transmitted to the business device 2. operation The device 2 is activated.

[0028] 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, and for example, the power of the shuttle shaft 12 is transmitted via a gear and a transmission shaft. 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.

[0029] 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 an actuated valve 25 is connected to the oil passage. Hydraulic oil discharged from a hydraulic pump 33 is supplied to the actuated valve 25. The first clutch 17 is switched between an engaged state and a disengaged state depending on the opening of the actuated valve 25. An oil passage is connected to the second clutch 18, and an actuated valve 26 is connected to the oil passage. Hydraulic oil discharged from the hydraulic pump 33 is supplied to the actuated valve 26. The second clutch 18 is switched between an engaged state and a disengaged state depending on the opening of the actuated valve 26. The actuated valves 25, 26 are, for example, two-position switching valves with solenoid valves. By energizing or de-energizing the solenoid of the solenoid valve of each actuated valve 25, 26, the corresponding clutch 17, 18 is switched between an engaged state and a disengaged state.

[0030] 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 the rear wheels 7R are driven, and the rotational speeds of the front wheels 7F and the 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 front wheels 7F and the rear wheels 7R are driven, but 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 only the rear wheels 7R are driven.

[0031] In other words, the power of the prime mover 4 is transmitted to the shuttle shaft 12 via the propeller shaft 5a, the main transmission unit 5b, the auxiliary transmission unit 5c, and the forward / reverse clutch 13, causing the shuttle shaft 12 to rotate in the forward or reverse direction, thereby driving the rear wheel differential unit 20R and causing the rear axle 21R and rear wheels 7R to rotate in the forward or reverse direction. Also, the power of the prime mover 4 is transmitted from the shuttle shaft 12 to the front transmission shaft 22 via clutches 17 and 18, causing the front transmission shaft 22 to rotate in the forward or reverse direction, thereby driving the front wheel differential unit 20F and causing the front axle 21F and front wheels 7F to rotate in the forward or reverse direction. This causes the body 3, i.e., the work vehicle 1, to move forward or backward.

[0032] The lifting device 8 includes a lift arm 8a, a lower link 8b, a top link 8c, a lift rod (not shown), and a lift cylinder 8e. The front end of the lift arm 8a is supported above or below the upper rear part of the case (transmission case) that houses the transmission 5 so as to be swingable. The lift arm 8a swings (ascends and descends) by the drive of the lift cylinder 8e. The lift cylinder 8e is composed of a hydraulic cylinder. The lift cylinder 8e is connected to the hydraulic pump 33 via the control valve 29. The control valve 29 is an electromagnetic valve or the like and expands and contracts the lift cylinder 8e.

[0033] The front end of the lower link 8b is supported above or below the lower rear part of the transmission 5 so as to be swingable. The front end of the top link 8c is supported above or below the rear part of the transmission 5 above the lower link 8b so as to be swingable. The lift arm 8a and the lower link 8b are connected by a lift rod. 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 (expands and contracts), the lift arm 8a ascends and descends, and at the same time, the lower link 8b connected to the lift arm 8a via the lift rod 8d ascends and descends. As a result, the working device 2 swings (ascends and descends) above or below with the front part of the lower link 8b as a fulcrum. The working vehicle 1 has an auto-up device that raises the lifting device 8 on the condition that the vehicle body 3 has reversed. In this embodiment, the auto-up device includes the lift cylinder 8e and the control valve 29.

[0034] 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 satellite 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 includes an antenna and the like and receives the satellite signals transmitted from the positioning satellite. The receiving device 41 is attached to, for example, the ROPS 6 (FIG. 12).

[0035] The inertial measurement unit 42 has an acceleration sensor that detects acceleration, a gyro sensor that detects angular velocity, etc. Based on the detection results of the inertial measurement unit 42, the roll angle, pitch angle, yaw angle, etc. of the vehicle body 3 can be detected.

[0036] The steering device 11 is a device that can perform manual steering, in which a driver seated in the driver's seat 10 steers the vehicle body 3 by operating the steering handle (steering wheel) 30, and automatic steering, in which the vehicle body 3 is steered automatically without the driver's operation.

[0037] The steering device 11 has a steering wheel 30, a steering shaft (rotation shaft) 31 that rotatably supports the steering wheel 30, and an assist mechanism (power steering device) 32. The assist mechanism 32 assists the rotation of the steering shaft 31 and the steering wheel 30 by hydraulic pressure or the like. The assist mechanism 32 includes a control valve 34 to which hydraulic oil discharged from a hydraulic pump 33 is supplied, and a steering cylinder 35 that is actuated 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 in accordance with 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.

[0038] When the driver turns the steering wheel 30 in one direction or the other, the switching position and opening of the control valve 34 change corresponding to the rotation direction 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 making it possible to change the steering direction of the front wheels 7F. In other words, the traveling direction of the vehicle body 3 can be changed left or right by manually steering the steering wheel 30.

[0039] The steering device 11 also has an automatic steering mechanism 37. The automatic steering mechanism 37 is a mechanism that automatically steers the vehicle body 3 based on the position of the vehicle body 3 detected by the positioning device 40. The automatic steering mechanism 37 is equipped with 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 integrally with the shaft 31, and a gear that is provided on the rotation shaft of the steering motor 38 and rotates integrally with the rotation shaft.

[0040] When the rotary shaft of the steering motor 38 rotates in the forward direction, the steering shaft 31 automatically rotates (turns) in the forward direction via the gear mechanism 39, and the front wheels 7F can be steered to one of the left and right directions. When the rotary shaft of the steering motor 38 rotates in the reverse direction, the steering shaft 31 automatically rotates in the reverse direction via the gear mechanism 39, and the front wheels 7F can be steered to the other of the left and right directions.

[0041] The control device 60 is made up of a CPU, memory, etc. The control device 60 controls the operation of each part of the work vehicle 1. The display device 45 is provided on an operation console 9F (Fig. 12) located in front of the driver's seat 10. The display device 45 displays driving information for the work vehicle 1 and various other information related to the work vehicle 1. The display device 45 also functions as an alarm device that issues alarms regarding automatic steering of the vehicle body 3.

[0042] Switches 50 to 54 are operation switches (operation members) for automatic steering operated by the driver of the work vehicle 1. Among them, the mode switch 50 is a switch for instructing switching to a setting mode for setting automatic steering. The setting mode is a mode for performing various settings related to automatic steering before starting automatic steering. For example, setting the start point and end point of the traveling reference line described later can be performed in the setting mode.

[0043] The setting switch 51 is a switch for instructing the setting of the traveling reference line for executing automatic steering when the setting mode is valid. The steering switches 52 and 54 are switches for instructing the start or stop of the automatic steering of the vehicle body 3 based on the traveling reference line. The correction switch 53 is a switch for instructing the correction of the position of the vehicle body 3 detected by the positioning device 40. That is, the position of the vehicle body 3 calculated from the satellite signal (position of the positioning satellite, transmission time, correction information, etc.) and the measurement information (acceleration, angular velocity) measured by the inertial measurement device 42 can be corrected by operating the correction switch 53. The control device 60 detects the operation states of the switches 50 to 54.

[0044] The PTO shift lever 24 is an operation member for the PTO operated by the driver of the work vehicle 1. FIG. 2 is a detailed view of the PTO shift lever 24. The PTO shift lever 24 is a lever operated to switch the rotation direction of the PTO shaft 16 or change (shift) the rotation speed of the PTO shaft 16. The PTO shift lever 24 is provided on the left side of the driver's seat 10 on the operation console 9L so as to be swingable back and forth (see FIGS. 12 and 7). By swinging the PTO shift lever 24, it switches from the neutral position Qn shown in FIG. 2 to any of the driving positions of the forward rotation first position Q1, the forward rotation second position Q2, the forward rotation third position Q3, and the reverse position Qb.

[0045] When the PTO shift lever 24 is not operated, the lever 24 is in the neutral position Qn, and the movable terminal 24f, which is linked to the lever 24, is connected to the fixed terminal 24a, and a signal is input from the power source to the input port 60a of the control device 60 via the terminals 24f, 24a and the input line 62a. This allows the control device 60 to detect that the PTO shift lever 24 is in the neutral position Qn. At this time, the PTO shaft 16 is stopped.

[0046] When the PTO shift lever 24 is swung forward one step A1 and the position of the lever 24 is switched to the first forward rotation position Q1, the movable terminal 24f is connected to the fixed terminal 24b, and a signal is input from the power supply to the input port 60b of the control device 60 via the terminals 24f, 24b and the input line 62b. When the PTO shift lever 24 is swung forward two steps A1 and the position of the lever 24 is switched to the second forward rotation position Q2, the movable terminal 24f is connected to the fixed terminal 24c, and a signal is input from the power supply to the input port 60c of the control device 60 via the terminals 24f, 24c and the input line 62c. Furthermore, when the PTO shift lever 24 is swung forward A1 in three stages and the position of the lever 24 is switched to the third forward position Q3, the movable terminal 24f is connected to the fixed terminal 24d, and a signal is input from the power source to the input port 60d of the control device 60 via the terminals 24f, 24d and the input line 62d.

[0047] When a signal is input to each of the input ports 60b, 60c, and 60d, the control device 60 detects that the PTO shift lever 24 has been switched to the first forward rotation position Q1, the second position Q2, or the third position Q3. When the PTO shift switch 24 is switched to the first forward rotation position Q1, the transmission 5 is activated to rotate the PTO shaft 16 in the forward direction at a predetermined first rotation speed. When the PTO shift switch 24 is switched to the second forward rotation position Q2, the transmission 5 is activated to rotate the PTO shaft 16 in the forward direction at a predetermined second rotation speed that is greater than the first rotation speed. When the PTO shift switch 24 is switched to the third forward rotation position Q3, the transmission 5 is activated to rotate the PTO shaft 16 in the forward direction at a predetermined third rotation speed that is greater than the second rotation speed.

[0048] Also, when the PTO shift lever 24L is swung rearward to A2 and the position of the lever 24 is switched to the reverse position Qb, the movable terminal 24f is connected to the fixed terminal 24e, and a signal is input from the power source to the input port 60e of the control device 60 through the terminals 24f, 24e and the input line 62e. Thereby, the control device 60 detects that the PTO shift lever 24 is in the reverse position Qb. At this time, due to the operation of the transmission 5, the PTO shaft 16 is rotationally driven in the reverse direction at a predetermined rotational speed.

[0049] Next, the automatic steering of the work vehicle 1 will be described. FIG. 3 is a diagram for explaining the automatic steering of the work vehicle 1. Before performing the automatic steering, first, a travel reference line L1 for performing the automatic steering is set. After setting the travel reference line L1, the automatic steering can be performed by setting a planned travel line L2 parallel to the travel reference line L1. In the automatic steering, the steering of the traveling direction of the vehicle body 3 of the work vehicle 1 is automatically performed so that the position of the vehicle body 3 measured by the positioning device 40 coincides with the planned travel line L2.

[0050] Specifically, before performing the automatic steering, the driver drives the work vehicle 1 and moves the work vehicle 1 to a predetermined position in the field (S1), and operates the mode switch 50 at the predetermined position. Then, the control device 60 shifts to the setting mode. Next, when the driver performs a start point registration operation with the setting switch 51 (S2), the control device 60 sets the position of the vehicle body 3 measured by the positioning device 40 at this time as the start point P10 of the travel reference line L1 (S3).

[0051] Next, the driver drives the work vehicle 1 manually from the start point P10 of the travel reference line L1 (S4) and stops at a predetermined position. Then, when the driver performs an end point registration operation with the setting switch 51 (S5), the control device 60 sets the position of the vehicle body 3 measured by the positioning device 40 at this time as the end point P11 of the travel reference line L1 (S6). Thereby, a straight line connecting the start point P10 and the end point P11 is set as the travel reference line L1.

[0052] Next, the driver moves the work vehicle 1 to a location different from the location where the travel reference line L1 is set (S7), and performs a start operation using the steering switch 52 (or the steering switch 54 (Fig. 1)) (S8). Then, the control device 60 sets a planned travel line L2 that is a straight line parallel to the travel reference line L1 (S9). After that, the control device 60 activates the automatic steering mechanism 37 to start automatic steering, and the driver operates a travel operation member provided on the vehicle body 3 (such as the accelerator pedal 182, the brake pedal 183 in Fig. 1, the shuttle lever 181 in Fig. 6, etc.), so that the work vehicle 1 travels along the planned travel line L2. The travel reference line L1 and the planned travel line L2 are displayed by the display device 45 and are visible to the driver.

[0053] For example, when the position of the vehicle body 3 is on the left side with respect to the planned travel line L2, the control device 60 activates the automatic steering mechanism 37 to steer the front wheels 7F to the right. Also, when the position of the vehicle body 3 is on the right side with respect to the planned travel line L2, the control device 60 activates the automatic steering mechanism 37 to steer the front wheels 7F to the left. During automatic steering, the driver can change the travel speed (vehicle speed) of the work vehicle 1 by changing the operation amount of the accelerator pedal 182, etc. or by changing the gear position of the transmission 5.

[0054] Also, after the start of automatic steering, when the driver performs a stop operation using the steering switch 52 at an arbitrary location, the control device 60 stops (ends) the automatic steering. That is, the end point of the planned travel line L2 is set by the stop of the automatic steering due to the stop operation of the steering switch 52. In other words, the length from the start point to the end point of the planned travel line L2 can be set longer or shorter than the travel reference line L1. In other words, the planned travel line L2 is not associated with the length of the travel reference line L1, and with the planned travel line L2, it is possible to travel while automatically steering a distance longer than the length of the travel reference line L1.

[0055] During the running of the work vehicle 1 by automatic steering, the position of the vehicle body 3 detected by the positioning device 40 may deviate from the actual position of the vehicle body 3. The deviation of the position of the vehicle body 3 can be corrected by the driver operating the correction switch 53.

[0056] Next, the relationship between the operation of the correction switch 53 during automatic steering and the behavior (travel locus) of the work vehicle 1 will be described. FIG. 4 is a diagram showing an example of the behavior of the work vehicle 1 during straight running by automatic steering. In FIG. 4, for example, for some time after the automatic steering is started in the work vehicle 1, the position of the actual vehicle body 3 (actual position) W2 and the position of the vehicle body 3 detected by the positioning device 40 (calculated vehicle body position) W1 coincide, and the actual position W2 and the planned travel line L2 coincide. In this case, the work vehicle 1 travels along the planned travel line L2. That is, in the section P1 where there is no error in the positioning of the positioning device 40 and the calculated vehicle body position W1 coincides with the actual position W2, the work vehicle 1 travels along the planned travel line L2.

[0057] Note that when there is no error in the positioning of the positioning device 40 and no correction is performed, the calculated vehicle body position W1 and the vehicle body position after correction by the correction switch 53 (corrected vehicle body position) W3 have the same value. The corrected vehicle body position W3 is obtained by subtracting the correction amount input by the correction switch 53 from the calculated vehicle body position W1 (corrected vehicle body position W3 = calculated vehicle body position W1 - correction amount).

[0058] For example, in the vicinity of position P20 in FIG. 4, although the actual position W2 is not deviated from the planned travel line L2, due to various influences, an error occurs in the positioning of the positioning device 40, and the calculated vehicle body position W1 detected by the positioning device 40 deviates to the right with respect to the planned travel line L2 (actual position W2), and the deviation amount W4 is maintained. In this case, the control device 60 determines that a deviation has occurred between the calculated vehicle body position W1 and the planned travel line L2, and steers the vehicle body 3 to the left so as to eliminate the deviation amount W4 between the calculated vehicle body position W1 and the planned travel line L2. Then, the actual position W2 of the vehicle body 3 shifts to the left away from the planned travel line L2.

[0059] After that, the driver notices that the position of the vehicle body 3 has shifted to the left from the planned travel line L2, and operates the correction switch 53 at the position P21 to input a correction amount for bringing the calculated vehicle body position W1 closer to the actual position W2. Then, the correction amount is added to the calculated vehicle body position W1, and the corrected vehicle body position W3 substantially coincides with the actual position W2. That is, by inputting the correction amount with the correction switch 53, the position of the vehicle body 3 detected by the positioning device 40 can be corrected in the direction of eliminating the deviation amount W4 generated near the position P20.

[0060] As shown in FIG. 4, after the position of the vehicle body 3 is corrected (position P21), when the actual position W2 is shifted to the left from the planned travel line L2, the vehicle body 3 is steered to the right by automatic steering, so that the actual position W2 of the vehicle body 3 comes to follow the planned travel line L2.

[0061] Now, in FIG. 3 described above, the case where the work vehicle 1 performs automatic steering while moving forward is shown, but the work vehicle 1 can also perform automatic steering while moving backward.

[0062] FIG. 5 is a diagram showing the automatic steering states when the work vehicle 1 moves forward and backward. For example, when performing automatic steering in the field H1, every time a start operation is performed with either of the steering switches 52, 54, the control device 60 sets straight line portions SLn (n = 1, 2, 3 ···) of a plurality of planned travel lines L2 parallel to the reference travel line L1. For example, when a start operation is performed with the steering switch 52 at the start position ST1 and an instruction to start automatic steering is given, the first straight line portion SL1 is set. Then, the control device 60 controls the transmission mechanism 5 and the automatic steering mechanism 37 to perform automatic steering while moving the vehicle body 3 forward along the straight line portion SL1. Also, when a stop operation is performed with the steering switch 52 at the end position EN1 and an instruction to stop automatic steering is given, the control device 60 controls the automatic steering mechanism 37 to end (stop) the automatic steering during the forward movement of the vehicle body 3 along the straight line portion SL1.

[0063] After this, for example, in order to perform work using the work equipment 2 attached to the work vehicle 1, after automatic steering while moving forward on the first straight section SL1 is completed, the driver attempts to perform automatic steering while moving the vehicle body 3 backward without turning the work vehicle 1.

[0064] In this case, for example, when a start operation is performed with the steering switch 54 at the start position ST2 to instruct the start of automatic steering, the control device 60 sets a second straight section SL2. Then, the control device 60 controls the transmission mechanism 5 and the automatic steering mechanism 37 to perform automatic steering while moving the vehicle body 3 backward along the straight section SL2. Specifically, when automatic steering is started with the steering switch 54, the control device 60 controls the drive of the steering motor 38 of the automatic steering mechanism 37 to rotate the steering shaft 31 and steer the front wheels 7F so that the vehicle body 3 moves backward along the straight section SL2. Then, when a stop operation is performed with the steering switch 54 at the end position EN2 to instruct the stop of automatic steering, the control device 60 controls the automatic steering mechanism 37 to end the automatic steering of the vehicle body 3 while moving backward along the straight section SL2.

[0065] Next, the operation console 9F will be described. Fig. 6 is a diagram showing the operation console 9F located in front of the driver's seat 10 as viewed from the driver's seat 10 side. The operation console 9F is provided with a steering handle 30 and a steering shaft 31 to which the handle 30 is connected. 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 includes a panel cover 178 and a column cover 179.

[0066] The panel cover 178 supports the display device 45. A support portion 178e for supporting the display device 45 is provided on the upper plate portion 178a of the panel cover 178. The support portion 178e supports the display device 45 in front of the steering shaft 31 and below the steering wheel 30. The mounting surface 178f of the upper plate portion 178a is provided behind the support portion 178e and below the steering wheel 30. The support portion 178e and the mounting surface 178f are continuous. The support portion 178e is located at the front portion of the upper plate portion 178a, and the mounting surface 178f is located at the rear portion of the upper plate portion 178a. A mode switch 50 and a correction switch 53 are installed on the mounting surface 178f. The setting switch 51 and the correction switch 53 are arranged around the steering shaft 31.

[0067] A shuttle lever 181 protrudes from the left plate portion 178b of the panel cover 178. The shuttle lever 181 is a member for performing an operation to switch the traveling direction of the vehicle body 3 to the front A1 or the rear A2. Specifically, by operating (swinging) the shuttle lever 181 forward to A1 (upper side in FIG. 6), the forward-reverse clutch 13 outputs forward power to the traveling device 7, and the traveling direction of the vehicle body 3 is switched to the front A1. Also, by operating the shuttle lever 181 rearward to A2 (lower side in FIG. 6), the forward-reverse clutch 13 outputs reverse power to the traveling device 7, and the traveling direction of the vehicle body 3 is switched to the rear A2. When the shuttle lever 181 is in the neutral position, no power is output to the traveling device 7.

[0068] The column cover 179 is arranged below the steering wheel 30 and covers the periphery of the upper portion of the steering shaft 31. The column cover 179 is formed in a substantially square tube shape and protrudes upward from the mounting surface 178f of the panel cover 178. That is, the mounting surface 178f is provided around the column cover 179. Therefore, the mode switch 50 and the correction switch 53 attached to the mounting surface 178f are arranged around the column cover 179.

[0069] The mode switch 50 is disposed at the lower left of the steering shaft 31. The mode switch 50 is composed of a push-button type switch. The mode switch 50 is electrically connected to the control device 60 by an electrical wiring 70 (FIG. 1) arranged inside the operation console 9F.

[0070] The correction switch 53 is disposed at the lower right of the steering shaft 31. The correction switch 53 is electrically connected to the control device 60 by an electrical wiring 73 (FIG. 1) arranged inside the operation console 9F. The correction switch 53 has a left correction key 53L and a right correction key 53R that can be pressed. By pressing the left correction key 53L, a left correction amount for correcting the position of the vehicle body 3 to the left is input to the control device 60. Also, by pressing the right correction key 53R, a right correction amount for correcting the position of the vehicle body 3 to the right is input to the control device 60.

[0071] By increasing the number of pressing operations of each correction key 53L, 53R, the left correction amount and the right correction amount can be increased. Each correction amount is obtained by multiplying the number of operations of each correction key 53L, 53R by a predetermined unit amount (correction amount = number of operations × unit amount). That is, each time each correction key 53L, 53R is pressed, each correction amount increases by the unit amount (for example, several centimeters or several tens of centimeters). The control device 60 detects the number of operations of the correction switch 53 and calculates the correction amount based on the number of operations.

[0072] On the left side of the steering shaft 31, an automatic steering lever 56 is installed in a protruding state to the left. The automatic steering lever 56 is swingable upward, downward, forward, and backward from the neutral position with a base end portion provided on the steering shaft 31 side as a fulcrum. The base end portion of the automatic steering lever 56 is provided inside the column cover 179. Inside the column cover 179, the aforementioned setting switch 51 and steering switch 52 (FIG. 1) are installed (detailed illustration omitted). The setting switch 51 and the steering switch 52 are electrically connected to the control device 60 by electrical wirings 71, 72 (FIG. 1) arranged inside the operation console 9F, respectively.

[0073] With the mode switch 50 operated and the setting mode enabled, by swinging the automatic steering lever 56 backward from the neutral position, the setting switch 51 is in a state where the starting point registration operation has been performed. At this time, an instruction (signal) to set the position of the vehicle body 3 detected by the positioning device 40 to the starting point P10 of the travel reference line L1 is input to the control device 60. Also, by swinging the automatic steering lever 56 forward from the neutral position, the setting switch 51 is in a state where the end point registration operation has been performed. At this time, an instruction to set the position of the vehicle body 3 detected by the positioning device 40 to the end point P11 of the travel reference line L1 is input to the control device 60.

[0074] After that, by swinging the automatic steering lever 56 downward from the neutral position, the steering switch 52 is in a state where the start operation has been performed, and an instruction to start automatic steering is input to the control device 60. Further, by swinging the automatic steering lever 56 upward from the neutral position, the steering switch 52 is in a state where the stop operation has been performed, and an instruction to stop automatic steering is input to the control device 60.

[0075] The mode switch 50, correction switch 53, and automatic steering lever 56 are collectively installed around the steering shaft 31. For this reason, the driver can clearly grasp the positions of the switches 50, 53 and the lever 56 at a glance. Also, the driver can operate the switches 50, 53 and the lever 56 without changing the posture while sitting in the driver's seat 10. As a result, when performing automatic steering while moving the vehicle body 3 forward, the operability of the switches 50, 51, 52, 53 for automatic steering is improved, and it becomes possible to prevent incorrect operations of the switches 50, 51, 52, 53. The switches 50 to 53 are the first operation parts installed on the operation console 9F in front of the driver's seat 10.

[0076] Note that the arrangement of the switches 50 to 53 and the lever 56 is not limited to the above-described arrangement, and any arrangement may be used. Also, the setting switch 51 and the steering switch 52 may be configured to be operable with separate operation knobs such as levers and buttons.

[0077] FIG. 7 is a perspective view of the work vehicle 1 as seen from the front. On the operation console 9L on the left side of the driver's seat 10, a PTO shift lever 24 for operating the aforementioned PTO shaft 16 is provided. Behind the driver's seat 10 at A2, a rollover protective structure (ROPS) 6 is installed. The ROPS 6 is composed of a pair of left and right support columns 6L, 6R and a beam 6b. The support columns 6L, 6R and the beam 6b are made of steel. The support column 6L is erected at the left rear part of the vehicle body 3, and the support column 6R is erected at the right rear part of the vehicle body 3. The beam 6b connects the upper ends of the support columns 6L, 6R to each other.

[0078] On the front surface of the support column 6L on the left side, a switch box 19 is attached. A magnet (not shown) is fixed to the mounting surface 19b of the switch box 19 in contact with the support column 6L (the back surface of the switch box 19 facing the rear A2 in FIG. 7, shown in FIG. 8 described later). Due to the magnetic force of this magnet, the switch box 19 can be detachably attached to the support column 6L.

[0079] On the front surface 19f facing the front A1 among the surfaces of the switch box 19 other than the mounting surface 19b, a steering switch 54 is provided. The steering switch 54 is a second operation unit for automatic steering that can be attached behind the driver's seat 10 and has the same function as the steering switch 52 included in the first operation unit installed on the operation console 9F.

[0080] The steering switch 54 has an on key 54a and an off key 54b. Inside the switch box 19, contacts of the steering switch 54, electrical wiring, etc. are provided. The switch box 19 is the housing of the second operation unit. The steering switch 54 is electrically connected to the control device 60 by an electrical wiring 74 (also refer to FIG. 1) routed from the switch box 19 behind the driver's seat 10 through the inside of the left side portion of the vehicle body 3 to the operation console 9F.

[0081] By pressing the on-key 54a, the steering switch 54 is put into the start operation state, and an instruction to start the automatic steering is input to the control device 60. By pressing the off-key 54b, the steering switch 54 is put into the stop operation state, and an instruction to stop the automatic steering is input to the control device 60.

[0082] When performing automatic steering while the work vehicle 1 is moving backward, the driver sitting in the driver's seat 10 turns around to the rear A2 for safety confirmation of the rear A2. In the turned posture, the driver can visually confirm the on-key 54a and the off-key 54b. Therefore, the driver starts the automatic operation during backward movement by pressing the on-key 54a, and stops the automatic steering during backward movement by pressing the off-key 54b. That is, the steering switch 54 is an operation unit for automatic steering during backward movement that is operated to start and stop automatic steering when the vehicle body 3 is moving backward.

[0083] However, the steering switches 52 and 54 can be used (are effective) when the vehicle body 3 is moving forward and backward. That is, whether the vehicle body 3 is moving forward or backward, by starting or stopping either of the steering switches 52 and 54, the control device 60 starts or stops the automatic steering. However, when the control device 60 starts the automatic steering upon receiving that one of the steering switches 52 and 54 has been started, until it receives that the one steering switch has been stopped and stops (ends) the automatic steering, it invalidates the other steering switch.

[0084] Specifically, for example, when the control device 60 receives that the steering switch 54 at the rear A2 has been started and starts the automatic steering during backward movement, until it receives that the steering switch 54 has been stopped and stops the automatic steering, it invalidates the steering switch 52, that is, does not accept the operation of the steering switch 52. Also, for example, when the control device 60 receives that the steering switch 52 at the front A1 has been started and starts the automatic steering during forward movement, until it receives that the steering switch 52 has been stopped and stops the automatic steering, it invalidates the steering switch 54, that is, does not accept the operation of the steering switch 54.

[0085] FIG. 8 is a perspective view of the switch box 19 and the support pillar 6L as viewed from the rear. The switch box 19, which is provided with the steering switch 54, is prevented from falling off from the support pillar 6L by a fall-off prevention mechanism 57. The fall-off prevention mechanism 57 is composed of a wire 58 and a snap ring 59. The wire 58 passes through the upper part of the switch box 19 from side to side and surrounds the support pillar 6L. Through holes 58a and 58b are formed at both ends of the wire 58 located behind the support pillar 6L. The snap ring 59 is disposed behind the support pillar 6L and passes through each of the through holes 58a and 58b of the wire 58. Therefore, the switch box 19 is restrained by the wire 58 and the snap ring 59 so as not to move away from the vicinity of the support pillar 6L.

[0086] In Figures 7 and 8, the switch box 19 including the steering switch 54 is attached to the front of the left support pillar 6L of the ROPS 6, but the switch box 19 can also be attached to the right support pillar 6R. As shown in Figure 7, the electrical wiring 74 of the switch box 19 extends from behind the driver's seat 10 to the outside (above) of the vehicle body 3, so the electrical wiring 74 does not get in the way of driving. Furthermore, since the electrical wiring 74 is long enough to be attached to either of the support pillars 6L or 6R from behind the driver's seat 10, the switch box 19 can be easily reattached from one of the support pillars 6L or 6R to the other. Furthermore, the switch box 19 can also be attached to any side of either of the support pillars 6L or 6R, any side of the beam 6b, or any position on the vehicle body 3. Note that, considering the operability of the steering switch 54, it is not recommended to attach the switch box 19 to the beam 6b (Figure 7), which is higher than the driver seated in the driver's seat 10.

[0087] Next, a description will be given of the control of the automatic steering linked to the PTO shaft 16 of the work vehicle 1. Figure 9 is a flowchart showing the operation of the work vehicle 1. Each process in Figure 9 is executed by the control device 60 in accordance with a software program stored in advance.

[0088] First, the control device 60 detects the states of the PTO shift lever 24 and the PTO shaft 16 (T1). The state of the PTO shaft 16 is detected, for example, based on the opening of the operating valve 27. Alternatively, a sensor may be provided to detect the rotational state of the PTO shaft 16, and the control device 60 may detect the state of the PTO shaft 16 based on an output signal from the sensor.

[0089] If the PTO shift lever 24 is in the neutral position Qn and the PTO shaft 16 is stopped (T2: YES), the control device 60 permits automatic steering when traveling in reverse (T3). Note that automatic steering when traveling forward is always permitted. Then, after the mode switch 50 or the setting switch 51 is operated to set the traveling reference line L1, if a start operation is performed on either the steering switch 52 or 54 (T4: YES), the control device 60 controls the automatic steering mechanism 37 to start automatic steering (T5). As a result, the work vehicle 1 performs automatic steering when traveling forward or automatic steering when traveling in reverse, depending on the traveling direction of the vehicle body 3.

[0090] Furthermore, the control device 60 notifies the driver of the work vehicle 1 of automatic steering information indicating the status of the automatic steering being performed and guidance related to the automatic steering by displaying it on the display device 45 (T6). At this time, for example, the display device 45 may display the travel reference line L1, planned travel line L2, and position of the work vehicle 1 in the field H1, as shown in Fig. 5. Alternatively, the status of the automatic steering and guidance related to the automatic steering may be notified audibly or visually using a buzzer, speaker, lighting, etc. provided on the work vehicle 1.

[0091] Furthermore, the control device 60 disables the steering switch that was not operated to start (T7). As a result, even if a steering switch that was not operated to start is erroneously operated, for example, automatic steering will not be stopped or new automatic steering will not be started in response to the erroneous operation.

[0092] Thereafter, if a stop operation is performed on the same steering switch that detected the start operation in process T4 (T8: YES), the control device 60 controls the automatic steering mechanism 37 to stop automatic steering (T9). The control device 60 also stops the notification of automatic steering information by the display device 45 (T10), and releases the disablement of the steering switch that was not operated (T11).

[0093] On the other hand, if the PTO shift lever 24 is not in the neutral position Qn or the PTO shaft 16 is in a driving state (T2: NO), the control device 60 prohibits automatic steering when traveling backward (T12). At this time, automatic steering when traveling forward is not prohibited.

[0094] Then, when a start operation is performed on either of the steering switches 52, 54 (T13: YES), the control device 60 detects the traveling direction of the vehicle body 3 based on the operating state of the shuttle lever 181 (FIG. 6) and the rotational state of the wheels 7F, 7R. Note that a sensor may be provided to detect the operating state of the shuttle lever 181 and the rotational state of the wheels 7F, 7R. If the traveling direction of the vehicle body 3 is forward A1 (T13: NO), the control device 60 controls the automatic steering mechanism 37 to start automatic steering for forward movement (T5). Then, the control device 60 executes the processes from process T6 onwards.

[0095] Furthermore, if the traveling direction of the vehicle body 3 is backward A2 (T14: YES), the control device 60 does not start automatic steering when traveling backward, and notifies the driver by displaying a message or the like on the display device 45 indicating that automatic steering when traveling backward is prohibited (T15). Furthermore, the control device 60 notifies the driver by displaying a guide on the display device 45 urging the driver to switch the PTO shift lever 24 to the neutral position Qn (T16).

[0096] The notification by the display device 45 for processes T15 and T16 may continue, for example, until the PTO shift lever 24 switches to the neutral position Qn and the PTO shaft 16 comes to a stop state, or may be performed for a certain period of time. Further, in processes T15 and T16, the fact that automatic steering during reverse is prohibited, guidance for switching the PTO shift lever 24 to the neutral position Qn, etc. may be notified audibly or visually by a buzzer, a speaker, lighting, etc. provided in the work vehicle 1. That is, a notification device capable of performing visual, audible, or tactile notification other than the display device 45 may be used. Furthermore, instead of process T16, for example, guidance prompting the stop of the PTO shaft 16 may be notified.

[0097] Also, in the above-described embodiment, when the PTO shift lever 24 is not in the neutral position Qn or the PTO shaft 16 is in the driving state (T2: NO in FIG. 9), the control device 60 prohibits automatic steering during reverse. However, based on the validity of either one of the condition of the PTO shift lever 24 and the condition of the PTO shaft 16, automatic steering during reverse may be prohibited.

[0098] Also, in the above-described embodiment, when the start of automatic steering is instructed by the operation of the steering switches 52 and 54 and the vehicle body 3 is moving in reverse (processes T13: YES, T14: YES in FIG. 9), the prohibition of the automatic steering during reverse and the switching guidance of the PTO shift lever 24 are notified by the display device 45 (processes T15, T16). However, when the start of automatic steering is instructed by the operation of the steering switches 52 and 54 and the vehicle body 3 is moving forward (processes T13: YES, T14: NO), the prohibition of the automatic steering during reverse and the switching guidance of the PTO shift lever 24 may also be notified by the display device 45. In this case, when performing automatic steering while moving in reverse, it is preferable to notify, by the display device 45 or the like, guidance prompting the switching of the PTO shift lever 24 to the neutral position Qn.

[0099] Also, in the above-described embodiment, the PTO shift lever 24 is provided as an operation member for operating the drive of the PTO shaft 16. However, for improving safety, etc., in addition to the lever 24, a PTO switch 23 as shown in FIG. 10 may be provided, for example.

[0100] 10 is a detailed view of the PTO switch 23. The PTO switch 23 is a switch that is operated to instruct driving and stopping of the PTO shaft 16. The PTO switch 23 is operably provided, for example, on an operation console 9L on the left side of the driver's seat 10. The PTO switch 23 can be switched from a neutral position Qx to either an off position Qy or an on position (driving position) Qz.

[0101] In an unoperated state, the PTO switch 23 is in the neutral position Qx, the movable terminal 23d of the switch 23 is connected to the fixed terminal 23a, and a signal is input from the switch 23 to the input port 60g of the control device 60 through the input line 61a. This allows the control device 60 to detect that the PTO switch 23 is in the neutral position Qx. At this time, the PTO shaft 16 is in a stopped state, and the PTO shaft 16 will not rotate even if the PTO shift lever 24 (FIG. 2) is switched to any of the drive positions Q1, Q2, Q3, or Qb.

[0102] When the PTO switch 23 is operated and switched to the ON position Qz, the movable terminal 23g is connected to the fixed terminal 23c, and a signal is input from the switch 23 to the input port 60i of the control device 60 through the input line 61c. This causes the control device 60 to detect that the PTO switch 23 has been switched to the ON position Qz. At this time, the PTO shaft 16 becomes drivable due to the operation of the transmission 5. That is, when the PTO shift lever 24 is switched to one of the drive positions Q1, Q2, Q3, or Qb, the PTO shaft 16 is driven to rotate in the forward or reverse direction at a predetermined rotation speed.

[0103] Furthermore, when the PTO switch 23 is operated and switched to the OFF position Qy, the movable terminal 23g is connected to the fixed terminal 23b, and a signal is input from the switch 23 to the input port 60h of the control device 60 through the input line 61b. This allows the control device 60 to detect that the PTO switch 23 has been switched to the OFF position Qy. At this time, the transmission 5 is activated, causing the PTO shaft 16 to stop.

[0104] As described above, the PTO shaft 16 can also be driven or stopped by operating the PTO switch 23. Therefore, instead of the position of the PTO shift lever 24, based on the position of the PTO switch 23, automatic steering during reverse may be permitted or prohibited. Specifically, for example, in the process T1 of FIG. 9, instead of the PTO shift lever 24, the state of the PTO switch 23 is detected, and in the process T2, it is only necessary to check whether the PTO switch 23 is in the neutral position Qx. The PTO shift lever 24 may be constituted by, for example, a shift lever or a select lever that can be swung back and forth and left and right.

[0105] In the above-described embodiment, the steering switch 54 is provided in the switch box 19 (FIG. 7) that can be attached to the rear A2 of the driver's seat 10 as an operation unit for automatic steering. However, the present invention is not limited to this. For example, as shown in FIG. 11, a correction switch 63 may be provided in the switch box 19 as an operation unit for automatic steering. The correction switch 63 has the same function as the correction switch 53 (FIG. 6) provided on the operation console 9F. The functions of the left correction key 63L and the right correction key 63R of the correction switch 63 are the same as those of the left correction key 53L and the right correction key 53R of the correction switch 53. According to such a configuration, when automatic steering is performed while the vehicle body 3 is moving backward, the driver can operate the correction keys 63L and 63R while looking at the rear A2 to correct the position of the vehicle body 3 detected by the positioning device 40. Further, when automatic steering is executed, when one of the correction switches 53 and 63 is operated, the control device 60 may invalidate the other switch until automatic steering ends.

[0106] Also, other operation units for automatic steering, such as the mode switch 50 and the setting switch 51, may be provided on at least one of the operation consoles 9F, 9L, and 9R in front of the driver's seat 10 or on the side, and the switch box 19 that can be attached to the rear A2 of the driver's seat 10. Further, the operation unit for automatic steering may be not only a push switch but also other types of switches such as a slide switch or a tumbler switch, or may be constituted by keys, levers, etc. other than switches.

[0107] The work vehicle 1 of this embodiment has the following effects. The work vehicle 1 of this embodiment includes a vehicle body 3 capable of traveling forward and backward by either manual steering or automatic steering with a steering wheel 30, a driver's seat 10 provided on the vehicle body 3, an operation console 9F provided in front of or on the side of the driver's seat 10, first operation units 50 to 53 for automatic steering provided on the operation console 9F, and second operation units 54, 63 for automatic steering that can be attached behind the driver's seat 10.

[0108] According to the above configuration, in the work vehicle 1, when performing automatic steering while moving the vehicle body 3 forward, the first operation units 50 to 53 for automatic steering provided in front of the driver's seat 10 or the like are operated. When performing automatic steering while moving the vehicle body 3 backward, the second operation units 54, 63 for automatic steering provided behind the driver's seat 10 can be operated. Therefore, when performing automatic steering, it is not necessary for the driver to move the operation units 50 to 54, 63 for automatic steering according to the traveling direction of the vehicle body 3, and it is possible to reduce the complexity of the operation.

[0109] Further, in this embodiment, the first operation units 50 to 53 and the second operation units 54, 63 include steering switches 52, 54 that are operated to instruct the start and stop of automatic steering. Thereby, when performing automatic steering while moving the vehicle body 3 forward, the steering switch 52 provided in front of the driver's seat 10 is operated. When performing automatic steering while moving the vehicle body 3 backward, the steering switch 54 provided behind the driver's seat 10 is operated, so that automatic steering can be started and stopped, and the operability is improved.

[0110] Furthermore, in this embodiment, the work vehicle 1 is equipped with a positioning device 40 capable of detecting the position of the vehicle body 3, and at least the first operation unit 50-53 of the first operation units 50-53 and second operation units 54, 63 includes a setting switch 51 that is operated to instruct setting of a driving reference line L1 that serves as a reference for automatic steering, and a correction switch 53 that is operated to instruct correction of the position of the vehicle body 3 detected by the positioning device 40. As a result, after operating the setting switch 51 to set the driving reference line L1, automatic steering can be performed by operating the steering switches 52, 54 according to the driving direction of the vehicle body 3. Furthermore, while automatic steering is being performed, the correction switch 53 can be operated to correct the position of the vehicle body 3 detected by the positioning device 40, allowing appropriate automatic steering to be performed.

[0111] 11, the second operation units 54, 63 include a correction switch 63 that is operated to instruct correction of the position of the vehicle body 3 detected by the positioning device 40. Therefore, by operating the correction switch 53, 63 according to the traveling direction of the vehicle body 3, the position of the vehicle body 3 detected by the positioning device 40 can be corrected, automatic steering can be performed appropriately, and the complexity of the driver's operations can be further reduced.

[0112] In addition, in this embodiment, the work vehicle 1 is equipped with a control device 60 that controls automatic steering, and when the setting switch 51 is operated when the vehicle body 3 starts and stops traveling by manual steering, the control device 60 sets a traveling reference line L1 based on the position of the vehicle body 3 detected by the positioning device 40, when the steering switches 52, 54 are operated to start, the control device 60 starts automatic steering, when the steering switches 52, 54 are operated to stop, the control device 60 stops automatic steering, when the correction switches 53, 63 are operated, the control device 60 corrects the position of the vehicle body 3, and when one of the switches with the same function (steering switches 52, 54, correction switches 53, 63) provided on the first operating unit 50-53 and the second operating unit 54, 63 is operated, the control device 60 disables the other switch until automatic steering ends.

[0113] This allows automatic steering to be performed appropriately while moving the vehicle body 3 forward or backward. Furthermore, when one of the steering switches 52, 54 and correction switches 53, 63, which have the same function, is used to start automatic steering or correct the position of the vehicle body 3, it is possible to prevent the other switch from being erroneously operated, causing automatic steering to be stopped or the position of the vehicle body 3 to be corrected unintentionally by the driver, thereby ensuring safety.

[0114] In addition, in this embodiment, the second operating unit 54 is electrically connected to the control device 60 by an electric wiring 74 that is routed from behind the driver's seat 10 through the side of the vehicle body 3 to the operating console 9F. This allows an input signal corresponding to the operation of the second operating unit 54 to be transmitted from the second operating unit 54 to the control device 60 through the electric wiring 74, making it possible to perform automatic steering in accordance with the operation of the second operating unit 54.

[0115] Furthermore, in this embodiment, a protection mechanism 6 that protects the driver's seat 10 is provided, and the second operating units 54, 63 are detachable from the protection mechanism 6. This allows the driver to attach the second operating units 54, 63 to a position of their choice on the protection mechanism 6, thereby improving the operability of the second operating units 54, 63.

[0116] In addition, in this embodiment, the protection mechanism 6 has pillars 6L, 6R erected respectively at the left and right rear portions of the vehicle body 3, and a beam 6b connecting the upper ends of the pillars 6L, 6R, and the second operating unit 54, 63 includes a housing (switch box) 19 that can be attached and detached to either of the pillars 6L, 6R, and operable keys 54a, 54a, 63L, 63R provided on a surface (front surface) 19f other than the mounting surface 19b of the housing 19 that contacts the pillar 6L.

[0117] As described above, when automatic steering is performed while the vehicle body 3 is moving in reverse, even if the driver looks back to the rear A2 to check for safety, the driver's field of vision can be prevented from being narrowed by the protection mechanism 6 and the second operating units 54, 63. Furthermore, the driver who looks back to the rear A2 can view the keys 54a, 54b, 63L, and 63R of the second operating units 54, 63 while checking for safety in the rear A2, thereby improving the operability of the keys 54a, 54b, 63L, and 63R.

[0118] Furthermore, in this embodiment, the work vehicle 1 is provided with a fall prevention member 57 that prevents the second operating unit 54 from falling off from the protection mechanism 6. This prevents the second operating unit 54 from coming off the protection mechanism 6 due to vibrations or the like transmitted from the work vehicle 1, and prevents the second operating unit 54 from being lost or damaged.

[0119] In addition, the work vehicle 1 of this embodiment is equipped with a vehicle body 3 that can travel forward and backward using either manual steering or automatic steering with a steering handle 30, a prime mover 4 provided on the vehicle body 3, a work device 2 supported on the vehicle body 3, a PTO shaft 16 that transmits the power of the prime mover 4 to the work device 2, and a control device 60 that controls automatic steering and the drive of the PTO shaft 16, and when the PTO shaft 16 is stopped, the control device 60 allows automatic steering when the vehicle body 3 is reversing, and when the PTO shaft 16 is driving, it prohibits automatic steering when the vehicle body 3 is reversing.

[0120] According to the above configuration, in the work vehicle 1, automatic steering when reversing is performed while the PTO shaft 16 is stopped, and automatic steering when reversing is not performed while the PTO shaft 16 is driving, so automatic steering when reversing can be performed stably and safely.

[0121] In addition, in this embodiment, the work vehicle 1 is equipped with PTO operating members 24, 23 (PTO shift lever 24, PTO switch 23) which are operating members for operating the drive of the PTO shaft 16 and can be switched from neutral positions Qn, Qx to drive positions Q1 to Q3, Qz. When the PTO operating members 24, 23 are in the neutral positions Qn, Qx, the PTO shaft 16 is stopped and the control device 60 allows automatic steering when the vehicle body 3 is reversing, and when the PTO operating members 24, 23 are switched to the drive positions Q1 to Q3, Qz, the control device 60 prohibits automatic steering when the vehicle body 3 is reversing, and the PTO shaft 16 becomes drivable.

[0122] According to the above configuration, when the PTO operating members 24, 23 are switched to the drive positions Q1 to Q3, Qz and the PTO shaft 16 is driven, automatic steering during reverse travel is disabled, but when the PTO operating members 24, 23 are in the neutral positions Qn, Qx and the PTO shaft 16 is stopped, automatic steering during reverse travel is enabled. This allows automatic steering during reverse travel of the work vehicle 1 to be performed stably and safely.

[0123] In addition, in this embodiment, the work vehicle 1 is equipped with a positioning device 40 capable of detecting the position of the vehicle body 3, a setting switch 51 that is operated to instruct the setting of a driving reference line L1 that serves as the basis for automatic steering, and steering switches 52, 54 that are operated to instruct the start and stop of automatic steering. In response to the operation of the setting switch 51, the control device 60 sets the driving reference line L1 based on the position of the vehicle body 3 detected by the positioning device 40 when the vehicle body 3 is traveling by manual steering, and if automatic steering is permitted when the vehicle body 3 is reversing, starts automatic steering in response to the start operation of the steering switches 52, 54 and performs automatic steering based on the driving reference line L1 and the position of the vehicle body 3 detected by the positioning device 40, stops automatic steering in response to the stop operation of the steering switches 52, 54, and if automatic steering when the vehicle body 3 is reversing is prohibited, does not start or stop automatic steering in response to the operation of the steering switches 52, 54.

[0124] According to the above configuration, automatic steering when reversing the work vehicle 1 can be performed reliably and stably by operating the setting switch 51 and the steering switches 52, 54. Furthermore, when automatic steering when reversing is prohibited, automatic steering when reversing will not be started even if the steering switches 52, 54 are operated to start, so safety can be ensured.

[0125] Furthermore, in this embodiment, the work vehicle 1 is equipped with a notification device (display device) 45 that notifies that automatic steering is prohibited when the vehicle body 3 is traveling in reverse. This prevents the driver of the work vehicle 1 from mistakenly thinking that there is a malfunction if automatic steering is not performed when automatic steering is prohibited when traveling in reverse on the work vehicle 1.

[0126] Furthermore, in this embodiment, the notification device 45 also issues a guidance message urging the driver to stop the PTO shaft 16. This allows the driver of the work vehicle 1 to realize that automatic steering during reverse travel is prohibited because the PTO shaft 16 is being driven, and that stopping the PTO shaft 16 will allow automatic steering during reverse travel.

[0127] Furthermore, in this embodiment, when automatic steering is prohibited when the vehicle body 3 is moving backward, the notification device 45 issues the notification when an instruction to start automatic steering is given. This allows the driver to know that automatic steering when moving backward is prohibited and that the cause of the prohibition is the drive of the PTO shaft 16, at the timing when the driver wants to start automatic steering of the work vehicle 1. Furthermore, the frequency of notifications by the notification device 45 can be reduced to prevent the driver from being bothered by the notifications and to reduce power consumption.

[0128] Although the present invention has been described above, the embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. 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]

[0129] 1 Work vehicle 2. Work equipment 3. Body 4. Prime Mover 16 PTO shaft 23 PTO switch (PTO operating member) 24 PTO shift lever (PTO operating member) 30 Steering wheel 40 Positioning device 45 Display device (alarm device) 51 Setting switch 52, 54 Steering switch 60 Control device L1 Driving reference line Q1 Forward rotation 1st position (drive position) Q2 Forward rotation 2nd position (drive position) Q3 Forward rotation 3rd position (drive position) Qb Reverse position (drive position) Qn, Qx neutral position Qz ON position (drive position)

Claims

1. A vehicle body capable of traveling forward and backward, A prime mover provided on the vehicle body, A working device supported by the vehicle body, A PTO shaft for transmitting the power of the prime mover to the working device, A steering wheel for manually steering the vehicle body, An automatic steering mechanism including an actuator for automatically steering the vehicle body, A positioning device for positioning the position of the vehicle body, A control device for controlling the automatic steering mechanism and detecting the driving and stopping states of the PTO shaft, comprising: The control device is During the forward and backward travel of the vehicle body when the vehicle speed is manually changed, based on the position of the vehicle body measured by the positioning device and the travel reference line, the automatic steering mechanism is actuated to perform automatic steering for automatically steering the vehicle body, When the PTO shaft is stopped, the automatic steering during the backward travel of the vehicle body is permitted, and when the start of the automatic steering is instructed, the automatic steering is executed, When the PTO shaft is driven, the automatic steering during the backward travel of the vehicle body is prohibited, and even when the start of the automatic steering is instructed, the automatic steering is not executed. A work vehicle.

2. An operating member for operating the drive of the PTO shaft, comprising a PTO operating member that can be switched from a neutral position to a drive position, When the PTO operating member is in the neutral position, the PTO shaft is stopped, and the control device permits the automatic steering during the backward travel of the vehicle body, When the PTO operating member is switched to the drive position, the control device prohibits the automatic steering during the backward travel of the vehicle body, and the PTO shaft becomes drivable. The work vehicle according to claim 1.

3. A setting switch operated to instruct the setting of the travel reference line serving as a reference for the automatic steering, A steering switch operated to instruct the start and stop of the automatic steering, comprising: The control device is In response to the operation of the setting switch, based on the position of the vehicle body detected by the positioning device during the travel of the vehicle body by manual steering, the travel reference line is set, When the automatic steering during the backward travel of the vehicle body is permitted, in response to the start operation of the steering switch, the automatic steering is started, and the automatic steering is executed based on the travel reference line and the position of the vehicle body detected by the positioning device, and in response to the stop operation of the steering switch, the automatic steering is stopped. The work vehicle according to claim 1 or 2, wherein when the automatic steering during reverse travel of the vehicle body is prohibited, the start and stop of the automatic steering are not performed in response to the operation of the steering switch.

4. The work vehicle according to any one of claims 1 to 3, further comprising a notification device that notifies that the automatic steering during reverse travel of the vehicle body is prohibited.

5. The work vehicle according to claim 4, wherein the notification device further notifies guidance prompting the stop of the PTO shaft.

6. The work vehicle according to claim 4 or 5, wherein the notification device performs the notification when the start of the automatic steering is instructed in a case where the automatic steering during reverse travel of the vehicle body is prohibited.

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