Tractor

Abstract

To prevent incorrect operation of a plurality of switches related to automatic steering.SOLUTION: A tractor includes: a steering handle; a steering shaft rotatably supporting the steering handle; a vehicle body which may travel with one of manual steering by the steering handle and automatic steering of the steering handle based on a travel plan line; a steering motor which rotates the steering handle during the automatic steering; a steering change-over switch which is disposed around the steering shaft and switches between start and ending of the automatic steering; an automatic steering mechanism which performs the automatic steering of the vehicle body; and a control device which controls the steering motor. The automatic steering mechanism has a gear mechanism including: a gear which is provided at the steering shaft and co-rotates with the steering shaft; and a gear which is provided at a rotary shaft of the steering motor and co-rotates with the rotary shaft. The steering change-over switch, the control device, and the gear mechanism are disposed below the steering handle.SELECTED DRAWING: Figure 10

Description

[Technical Field]

[0001] The present invention relates to a tractor. [Background technology]

[0002] BACKGROUND ART A work vehicle (tractor) disclosed in Patent Document 1 is known in the art. The work vehicle disclosed in Patent Document 1 is equipped with a GPS position calculation means that receives radio waves transmitted from GPS satellites and calculates the position of the vehicle, a steering drive means that rotates the steering device, an engine rotation control means, a speed change means, and a control unit that controls these, and is equipped with an automatic driving mode that controls the steering drive means, engine rotation control means, and speed change means to enable automatic driving so that the vehicle travels along a set route based on the vehicle's position, and a manual driving mode that enables the vehicle to travel in accordance with manual operation of the speed change operation means, steering operation means, and engine rotation operation means. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-182453 Summary of the Invention [Problem to be solved by the invention]

[0004] The above-mentioned work vehicle is equipped with an automatic / manual changeover switch, which serves as a mode changeover operating means for switching between automatic driving mode and manual driving mode. However, Patent Document 1 does not disclose the specific location of the automatic / manual changeover switch, nor does it disclose a switch for switching to a setting mode for setting before the start of automatic steering. Therefore, with the work vehicle disclosed in Patent Document 1, it is difficult to reliably prevent erroneous operation of multiple switches related to automatic steering.

[0005] The present invention has been made in consideration of the above-described conventional technology, and aims to provide a work vehicle (tractor) that can reliably prevent erroneous operation of multiple switches related to automatic steering. [Means for solving the problem]

[0006] A tractor according to one aspect of the present invention includes a steering handle, a steering shaft that rotatably supports the steering handle, a vehicle body that can travel by either manual steering using the steering handle or automatic steering of the steering handle based on a planned travel line, a steering motor that rotates the steering handle during the automatic steering, a steering changeover switch that is disposed around the steering shaft and switches between starting and ending the automatic steering, an automatic steering mechanism that performs automatic steering of the vehicle body, and a control device that controls the steering motor, wherein the automatic steering mechanism has a gear mechanism that includes a gear that is disposed on the steering shaft and rotates together with the steering shaft, and a gear that is disposed on a rotation shaft of the steering motor and rotates together with the rotation shaft, and the steering changeover switch, the control device, and the gear mechanism are disposed below the steering handle. The steering motor, the gear mechanism, and the control device are arranged side by side along the axial direction of the steering shaft in a side view, and the control device is arranged on the opposite side of the steering motor with the gear mechanism in between in a side view in the axial direction of the steering shaft. .

[0007] Preferably, the gear mechanism is disposed below the steering changeover switch. Preferably, the gear mechanism is disposed across one side and the other side of the steering shaft.

[0008] Preferably, the gear mechanism includes a first gear attached to the output shaft of the steering motor, a second gear meshing with the first gear, and a fourth gear attached to the steering shaft and rotating together with the steering shaft as the second gear rotates. Preferably, the gear mechanism includes a third gear connected to the second gear by a connecting shaft, the second gear and the third gear rotate integrally with the connecting shaft, and the fourth gear meshes with the third gear.

[0010] Preferably, the tractor is equipped with a display device capable of displaying tractor operating information and a panel cover supporting the display device, and the steering motor, the gear mechanism and the control device are arranged inside the panel cover. Preferably, the control device has a housing and a circuit board arranged within the housing, and the housing is rectangular and arranged vertically inside the panel cover with the shortest side facing in the vehicle body width direction or approximately in the vehicle body width direction. [Effects of the Invention]

[0011] According to the above tractor, it is possible to reliably prevent erroneous operation of multiple switches related to automatic steering. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a diagram showing the configuration and control block diagram of a work vehicle (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] FIG. 10 is an explanatory diagram illustrating an automatic operation. [Figure 7] FIG. 2 is a plan view showing a main part of the internal structure of the front part of the vehicle body. [Figure 8]FIG. 2 is a left side view showing a main part of the internal structure of the front part of the vehicle body. [Figure 9] FIG. 2 is a right side view showing a main part of the internal structure of the front part of the vehicle body. [Figure 10] FIG. 2 is a rear view showing the main parts of the internal structure of the front part of the vehicle body. [Figure 11] FIG. 2 is a rear view showing the steering handle, the cover, etc. [Figure 12] 1 is a view of the panel cover and the like viewed from a direction perpendicular to the display surface of the display device. [Figure 13] FIG. 2 is a view of the panel cover and the like as seen from above in the axial direction of the steering shaft. [Figure 14] FIG. 10 is a left side view illustrating the movement of the steering changeover switch. [Figure 15] FIG. 2 is a rear perspective view showing a main part of the internal structure of the front part of the vehicle body. [Figure 16] FIG. 8 is an enlarged plan view showing a part (front part) of FIG. 7. [Figure 17] FIG. 2 is a right rear perspective view showing the steering handle, gear mechanism, etc. [Figure 18] FIG. 10 is a view showing the gear mechanism as seen from the left. [Figure 19] FIG. 2 is a perspective view showing the mounting structure of the inertial measurement unit. [Figure 20] FIG. 2 is a plan view showing the mounting structure of the inertial measurement unit. [Figure 21] FIG. 2 is a perspective view showing an inertial measurement unit, a support member, a vibration-isolating member, and a support plate. [Figure 22] FIG. 2 is a right side view showing the mounting structure of the inertial measurement unit. [Figure 23] FIG. 2 is an enlarged right side view showing the rear part of the mounting structure for the inertial measurement unit. [Figure 24] 21 is a cross-sectional view taken along line AA in FIG. 20. [Figure 25] FIG. 25 is an enlarged cross-sectional view showing a part (left part) of FIG. 24. [Figure 26] FIG. 2 is a schematic plan view illustrating the mounting position of the inertial measurement unit. [Figure 27] FIG. 2 is a diagram showing an example of a first screen and a second screen that can be switched by a screen switching switch. [Figure 28] FIG. 1 is a left side view of a work vehicle (tractor). [Figure 29] FIG. 1 is a plan view of a work vehicle (tractor). DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. <Outline of the work vehicle> Figure 28 is a side view showing one embodiment of the work vehicle 1, and Figure 29 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 tractors, and may be agricultural machinery (agricultural vehicles) such as a combine harvester or transplanter, or construction machinery (construction vehicles) such as a loader work machine.

[0014] 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. 28) will be referred to as the front, the rear side of the driver (the direction of arrow A2 in FIG. 28) will be referred to as the rear, the left side of the driver (the direction of arrow B1 in FIG. 29) will be referred to as the left side, and the right side of the driver (the direction of arrow B2 in FIG. 29) will be referred to as the right side. In addition, the horizontal direction (the direction of arrow B3 in FIG. 29), which is perpendicular to the fore-and-aft direction of the tractor 1, will be referred to as the vehicle body width direction.

[0015] As shown in FIG. 28, 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. 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.

[0016] Furthermore, a coupling section 8 configured with a three-point link mechanism or the like is provided at the rear of the vehicle body 3. A working device can be attached and detached to the coupling section 8. By connecting the working device to the coupling section 8, 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 or the like, a spreading device for spreading grass or the like, a grass collecting device for collecting grass or the like, a shaping device for shaping grass or the like, and the like.

[0017] 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.

[0018] The auxiliary transmission unit 5c, like the main transmission unit 5b, has a plurality of gears and a shifter for changing the connection of the gears. The auxiliary transmission unit 5c uses the shifter to appropriately change the connection (mesh) of the plurality of gears. By this, the rotation input from the main transmission unit 5b is changed and output (speed is changed). 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.

[0019] 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.

[0020] The front transmission unit 5f has a first clutch 17 and a second clutch 18. The first clutch 17 and the second clutch can transmit power from the propeller shaft 5a, for example, the power of 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 20R rotatably supports the front axle 21F to which the front wheels 7F are attached.

[0021] The first clutch 17 and the second clutch 18 are composed of 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 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.

[0022] 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 and rear wheels are driven by power, resulting in four-wheel drive (4WD), and the rotational speeds of the front and rear wheels 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 is faster than the rotational speed of the rear wheels (4WD accelerated speed state). Furthermore, when the first clutch 17 and the second clutch 18 are engaged, the power of the shuttle shaft 12 is not transmitted to the front wheels 7F, resulting in two-wheel drive (2WD), where the rear wheels are driven by power. <Outline of position detection device> The tractor 1 is equipped with a position detection device 40. The position detection device 40 is a device that detects 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 position detection device 40 receives a reception signal (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 reception signal. The position detection device 40 has a receiving device 41 and an inertial measurement unit (IMU) 42.

[0023] The receiving device 41 has an antenna and the like and is a device for receiving signals transmitted from positioning satellites, and is attached to the vehicle body 3 separately from the inertial measurement unit 42. In this embodiment, The receiving device 41 is attached to a ROPS 61 provided on the vehicle body 3. The attachment location of the receiving device 41 is not limited to that in the embodiment. 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. <Outline of steering devices, manual steering, and automatic steering> 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.

[0024] 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 manual steering of the steering handle 30. More specifically, 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 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.

[0025] 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.

[0026] Next, automatic steering will be described. 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 body position measured by the position detection device 40 coincides with the planned driving line L2.

[0027] Specifically, before performing automatic steering, 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 position detection device 40 is set to 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 position detection device 40 is set to 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.

[0028] 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 a transmission.

[0029] 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.

[0030] 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 a position detection device 40. More specifically, the automatic steering mechanism 37 automatically steers the steering wheel 30 based on a signal received by a receiving device 41 and inertia measured by an inertial measurement device 42. The automatic steering mechanism 37 includes a steering motor 38 and a gear mechanism 39. The steering motor 38 is a motor whose rotation direction, rotation speed, rotation angle, etc. can be controlled based on the vehicle body position. The gear mechanism 37 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 a rotation shaft of the steering motor 38 and rotates together with the rotation shaft. When the rotary shaft of the steering motor 38 rotates, the steering shaft 31 automatically rotates (turns) via the gear mechanism 37, and the steering direction of the front wheels 7F can be changed so that the vehicle body position coincides with the intended driving line L2. <Display device overview> 1 and 12, 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. <Outline of setting switch and steering selector switch> 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.

[0031] 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.

[0032] 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 in the setting mode. Specifically, the steering selector switch 52 can be switched from a neutral position to up, down, forward, or backward. When the setting mode is enabled and the steering selector switch 52 is switched from the neutral position to down, it outputs a command to start automatic steering. When the setting mode is enabled and the steering selector switch 52 is switched from the neutral position to up, it outputs a command to end automatic steering. When the setting mode is enabled and the steering selector switch 52 is switched from the neutral position to back, it outputs a command to set the current vehicle body position to the start point P10 of the driving reference line L1. When the setting mode is enabled and the steering selector switch 52 is switched from the neutral position to forward, it outputs a command to set the current vehicle body position to the end point P11 of the driving reference line L1. <Compensation switch overview> The tractor 1 is provided with a correction switch 53. The correction switch 53 is a switch for correcting the vehicle body position (latitude, longitude) measured by the position detection device 40. Switch 53 is a switch that corrects the vehicle position (called the calculated vehicle position) calculated using the received 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.

[0033] 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. 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.

[0034] 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.

[0035] 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 (vehicle body 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.

[0036] 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.

[0037] 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. Next, the relationship between the correction amount (left correction amount, right correction amount) by the correction switch 53, the planned traveling route L2, and the behavior (traveling trajectory) of the tractor 1 (vehicle body 3) will be described.

[0038] 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 route L2, the tractor 1 travels along the planned traveling route L2. That is, in section P1 where there is no error in the positioning of the position detection device 40 and the vehicle body position (calculated vehicle body position W1) detected by the position detection device 40 is the same as the actual position W2, the tractor 1 travels along the planned traveling route L2. Note that if there is no error in the positioning of the position detection device 40 and no correction is made, the calculated vehicle body position W1 and the vehicle body position (corrected vehicle body position) W3 corrected with the correction amount are the same value. The corrected vehicle body position W3 is calculated vehicle body position W3 = calculated vehicle body position W1 - correction amount.

[0039] Here, suppose that near position P20, even though actual position W2 is not deviated from planned travel route L2, various influences cause an error in the positioning of position detection device 40, causing vehicle body position W1 detected by position detection device 40 to deviate to the right from planned travel route 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 travel route L2, and steers tractor 1 left to eliminate deviation amount W4 between calculated vehicle body position W1 and planned travel route L2. Then, steering left shifts actual position W2 of tractor 1 toward planned travel route L2. Suppose that the driver subsequently notices that tractor 1 is deviating from planned travel route 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 position detection 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 planned traveling route 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 planned traveling route L2.

[0040] 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 initiated, if the actual position W2 and the calculated vehicle body position W1 coincide and the actual position W2 and the planned traveling route L2 coincide, the tractor 1 travels along the planned traveling route L2, as in Figure 5A. That is, as in Figure 5A, in section P2 where there is no error in the positioning of the position detection device 40, the tractor 1 travels along the planned traveling route L2. Also, as in Figure 5A, the calculated vehicle body position W1 and the corrected vehicle body position W3 are the same value.

[0041] Here, suppose that at position P22, an error occurs in the positioning of the position detection device 40 due to various influences, causing the vehicle body position W1 detected by the position detection 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 planned travel route L2. Suppose that the driver then notices that the tractor 1 has deviated from the planned travel route L2 and operates 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 position detection device 40 can be corrected in a direction that eliminates the deviation amount W5 that occurred near position P22. Furthermore, as shown in position P23 in Figure 5B, if, after correcting the vehicle position, the actual position W2 of the tractor 1 is away to the right from the planned driving route 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 route L2. <Outline of the control device> 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.

[0042] The first control device 60A receives the received signal (received information) received by the receiving device 41 and the 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 the 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 the 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.

[0043] 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 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.

[0044] 6, when the deviation between the vehicle body position and the planned travel line L2 is less than a threshold value, the second control device 60B 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 positioned to the left of the planned travel line L2, the second control device 60B rotates the rotation shaft of the steering motor 38 so that the steering direction of the tractor 1 is rightward. 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 positioned to the right of the planned travel line L2, the second control device 60B rotates the rotation shaft of the steering motor 38 so that the steering direction of the tractor 1 is leftward. 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), i.e., if the angle θ of the vehicle body orientation F1 with respect to the planned travel line L2 is equal to or greater than a threshold value, the second control device 60B may set the steering angle so that the angle θ is zero (the vehicle body orientation F1 matches the orientation of the planned travel line L2). Furthermore, the second control device 60B 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 θ). The setting of the steering angle in automatic steering in the above-described embodiment is an example and is not limiting.

[0045] The third control device 60C raises and lowers the connecting portion 8 in response to the operation of an operating member provided around the driver's seat 10. The control of the traveling system, the control of the working system, and the calculation of the vehicle body position are not limited to those described above. <Specific configuration of the vehicle body, etc.> As shown in FIG. 28, the vehicle body 3 has a front axle frame 70, a flywheel housing 71, a clutch housing 72, an intermediate frame 73, and a transmission case 74.

[0046] The front axle frame 70 is disposed at the front of the vehicle body 3 and rotatably supports the axle (front axle) 21F of the front wheels 7F. The front axle frame 70 also supports the engine 4 and extends forward from the engine 4. The front axle frame 70, the flywheel housing 71, the crankshaft 72, the crankshaft 74, the crankshaft 76, the crankshaft 78, the crankshaft 79, the crankshaft 710, the crankshaft 79 ... The latch housing 72, the intermediate frame 73, and the transmission case 74 are integrally connected to form a highly rigid vehicle body frame.

[0047] The flywheel housing 71 is connected to the rear of the prime mover 4 and houses a flywheel connected to the output shaft of the prime mover 4. The clutch housing 72 is connected to the flywheel housing 71 and houses a clutch that intermittently transmits the power of the prime mover 4 transmitted via the flywheel. The intermediate frame 73 is connected to the rear of the clutch housing 72 and extends rearward from the clutch housing 72. The transmission case 74 is connected to the rear of the intermediate frame 73 and houses the transmission 5 and the rear wheel differential device 20R.

[0048] As shown in Fig. 7, the front axle frame 70 has a first frame 70A arranged on one side (left side) in the vehicle width direction, a second frame 70B arranged on the other side (right side) in the vehicle width direction, and a third frame 70C connecting the first frame 70A and the second frame 70B. As shown in Figs. 7, 28, and 29, a weight 75 is attached to the front end of the front axle frame 70. In addition, a hood 76 is attached to the upper part of the front axle frame 70.

[0049] The hood 76 covers the prime mover 4. More specifically, the hood 76 has an upper plate portion 76a that covers the top of the prime mover 4, a left plate portion 76b that covers the left side of the prime mover 4, a right plate portion 76c that covers the right side of the prime mover 4, and a front plate portion 76d that covers the front of the prime mover 4. A cover 77 that houses the steering shaft 31 and the like is provided at the rear of the hood 76. A steering handle 30 is provided above the cover 77 and in front of the driver's seat 10. <Panel covers, column covers> As shown in Figures 8 to 10, the outer periphery of the steering shaft 31 is covered by a steering post 80. The steering post 80 is cylindrical and extends along the axial direction of the steering shaft 31. As shown in Figures 8 and 9, the outer periphery of the steering post 80 is covered by a cover 77. The cover 77 is provided in front of the driver's seat 10. As shown in Figures 14, 28 and 29, the cover 77 includes a panel cover 78 and a column cover 79.

[0050] As shown in Figures 11 to 14, 28, and 29, the panel cover 78 has an upper plate portion 78a, a left plate portion 78b, a right plate portion 78c, and a rear plate portion 78d. The front end of the left plate portion 78a of the panel cover 78 is connected to the left plate portion 76b of the hood 76. The front end of the right plate portion 78c of the panel cover 78 is connected to the right plate portion 76c of the hood 76. The rear plate portion 78d of the panel cover 78 connects the rear end of the left plate portion 78b to the rear end of the right plate portion 78c. The upper plate portion 78a of the panel cover 78 connects the upper end of the left plate portion 78b, the upper end of the right plate portion 78c, and the upper end of the rear plate portion 78d, and is connected to the upper plate portion 76a of the hood 76.

[0051] 11 to 14, a support portion 78e that supports the display device 45 is provided on the upper plate portion 78a of the panel cover 78. The support portion 78e supports the display device 45 in front of the steering shaft 31 and below the steering handle 30. In this embodiment, the display device 45 is composed of a liquid crystal panel. As shown in FIG. 13, the display device 45 is arranged around the steering shaft 31. More specifically, the display device 45 is arranged in front of the steering shaft 31. As shown in FIG. 12, the display device 45 is arranged in a position (inside the grip 30a) that does not overlap with the grip 30a of the steering handle 30 when viewed in a direction perpendicular to the display surface of the display device 45 (hereinafter referred to as the "display surface perpendicular direction"). The display screen perpendicular direction generally coincides with the line of sight of the driver seated in the driver's seat 10, so that the visibility of the display device 45 is good.

[0052] 11 to 14, the upper plate portion 78a of the panel cover 78 has a mounting surface 78f to which the setting switch 51, the correction switch 53, and the screen changeover switch 54 are attached. That is, the panel cover 78 is provided with the setting switch 51, the correction switch 53, and the screen changeover switch 54. The mounting surface 78f is provided behind the support portion 78e and below the steering handle 30. The support portion 78e and the mounting surface 78f are configured as a continuous, integrated unit, with the support portion 78e located in front of the upper plate portion 78a and the mounting surface 78f located in the rear of the upper plate portion 78a.

[0053] As shown in FIGS. 8, 9, 11, and 14, the mounting surface 78f is inclined downward toward the rear. As shown in FIG. 12, the mounting surface 78f has a first region 78f1, a second region 78f2, and a third region 78f3 provided around the steering shaft 31. The first region 78f1 is located on one side (left) of the steering shaft 31. The second region 78f2 is located on the other side (right) of the steering shaft 31. The third region 78f3 is located behind the steering shaft 31. The setting switch 51, the correction switch 53, and the screen changeover switch 54 are attached to one of three regions (the first region 78f1, the second region 78f2, and the third region 78f3) of the mounting surface 78f, and are arranged around the steering shaft 31. The specific locations of the setting switch 51, the correction switch 53, and the screen changeover switch 54 will be described later.

[0054] As shown in Figures 11 to 14, 28, and 29, a shuttle lever 81 protrudes from the left portion (left plate portion 78b) of the panel cover 78. The shuttle lever 81 protrudes leftward from the left portion of the panel cover 78 and then extends upward. The shuttle lever 81 is a member that switches the traveling direction of the vehicle body 3. To explain in more detail, by operating (swinging) the shuttle lever 81 forward, the forward / reverse travel switching unit 13 is set to 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. On the other hand, by operating (swinging) the shuttle lever 81 backward, the forward / reverse travel switching unit 13 is set to 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 81 is in the neutral position, no power is output to the traveling device 7.

[0055] A grip portion 81a to be gripped by the operator is provided at the tip (upper end) of the shuttle lever 81. As shown in Fig. 11, the grip portion 81a is located to the left of the grip 30a of the steering handle 30. The grip portion 81a is also located above the mounting surface 78f of the panel cover 78 and at a distance to the left of the mounting surface 78f. This prevents the operator from unintentionally touching the various switches (such as the setting switch 51) provided on the mounting surface 78f when operating the shuttle lever 81, or from unintentionally touching the shuttle lever 81 when operating the various switches provided on the mounting surface 78f.

[0056] As shown in FIGS. 11 to 14, 28, and 29, the column cover 79 is disposed below the steering wheel 30. As shown in FIGS. 8 and 9, the column cover 79 covers the periphery of the upper part of the steering shaft 31 and the steering post 80. The column cover 79 is formed in a substantially rectangular tubular shape and protrudes upward from the mounting surface 78f of the panel cover 78. As shown in FIG. 12, a first region 78f1, a second region 78f2, and a third region 78f3 of the mounting surface 78f are disposed on one side (left), the other side (right), and the rear of the column cover 79, respectively. In other words, the mounting surface 78f is provided around the periphery of the column cover 79. The setting switch 51, the correction switch 53, and the screen changeover switch 54 attached to the mounting surface 78f are disposed around the periphery of the column cover 79.

[0057] As shown in FIGS. 8, 9, 11 to 14, the mounting surface 78f is The mounting surface 78f is connected to the lower end of the column cover 79 and is located at the same height as the lower end of the column cover 79. Therefore, the mounting surface 78f is spaced apart from the grip 30a of the steering wheel 30 by the height of the column cover 79. As a result, the setting switch 51, correction switch 53, and screen changeover switch 54 attached to the mounting surface 78f are located at positions away from the steering wheel 30.

[0058] By locating the setting switch 51, the correction switch 53, and the screen changeover switch 54 at positions away from the steering wheel 30, it is possible to prevent unintentional contact with the setting switch 51, the correction switch 53, and the screen changeover switch 54 when operating the steering wheel 30. It is also possible to prevent unintentional contact with the steering wheel 30 when operating the setting switch 51, the correction switch 53, and the screen changeover switch 54. This makes it possible to prevent unintentional switching to automatic steering due to erroneous operation, etc. <Switch placement> Next, the arrangement of the setting switch 51, steering changeover switch 52, correction switch 53, and screen changeover switch 54 will be described.

[0059] 11 to 13, the setting switch 51, steering changeover switch 52, correction switch 53, and screen changeover switch 54 are arranged around the steering shaft 31. The specific arrangement of the setting switch 51, steering changeover switch 52, correction switch 53, and screen changeover switch 54 will be described below. 11 to 13, the setting switch 51 is disposed on one side (left side) of the steering shaft 31 in the vehicle body width direction. The setting switch 51 is also disposed rearward of the steering shaft 31 in the front-to-rear direction. In other words, the setting switch 51 is disposed leftward and rearward (diagonally rear left) of the steering shaft 31. In this embodiment, the setting switch 51 is configured as a push switch.

[0060] In terms of its position relative to the column cover 79, the setting switch 51 is disposed to the left and rear (diagonally rear left) of the column cover 79. In terms of its position relative to the mounting surface 78f of the panel cover 78, the setting switch 51 is disposed at the rear of the first region 78f1 of the mounting surface 78f. Furthermore, in terms of its position relative to the display device 45, the setting switch 51 is disposed behind the display device 45 (on the driver's seat 10 side). This allows the driver to easily and accurately operate the setting switch 51 while checking the display device 45 without changing his / her posture seated in the driver's seat 10.

[0061] 13, the setting switch 51 does not overlap with the grip 30a of the steering handle 30 when viewed in the axial direction of the steering shaft 31. Specifically, the setting switch 51 is arranged inside the grip 30a of the steering handle 30 (on the side closer to the axis of the steering shaft 31) when viewed in the axial direction of the steering shaft 31.

[0062] As shown in FIGS. 11 to 13, the steering changeover switch 52 is disposed on one side (left side) 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 portion provided on the steering shaft 31 side as a fulcrum. The base end portion of the steering changeover switch 52 is provided inside the column cover 79. The steering changeover switch 52 protrudes from one side (left side) of the column cover 79.

[0063] A grip portion 52a to be gripped by an operator is provided at the tip (left end) of the steering changeover switch 52. As shown in Figs. 11, 14, etc., the grip portion 52a is disposed below and in the vicinity of the grip 30a of the steering handle 30. Furthermore, as shown in Fig. 13, the grip portion 52a overlaps with the grip 30a of the steering handle 30 when viewed from the axial direction of the steering shaft 31. This allows the operator to operate the steering changeover switch 52 by reaching out their fingers to the grip portion 52a while gripping the grip 30a of the steering handle 30.

[0064] Here, the grip portion 81a of the shuttle lever 81 is located below and to the left of the grip 30a of the steering handle 30, and is positioned out of reach of the fingers when gripping the grip 30a. Therefore, when operating the steering selector switch 52 while gripping the grip 30a, it is possible to prevent the shuttle lever 81 from being operated unintentionally. Furthermore, when operating the shuttle lever 81, it is also possible to prevent the steering selector switch 52 from being operated unintentionally.

[0065] As shown in Figure 14, the steering switch 52 can be swung in a first direction (indicated by arrows C1 and C2) to switch between starting and ending automatic operation, and a second direction (indicated by arrows D1 and D2) to set the start and end points of a driving reference line that serves as the basis for the planned driving line. The swing in the first direction is swinging upward or downward from the neutral position. The swing in the second direction is swinging forward or backward from the neutral position. When the setting mode is enabled, the steering selector switch 52 commands (outputs) the start of automatic steering by swinging downward from the neutral position (in the direction of arrow C1), and commands (outputs) the end of automatic steering by swinging upward from the neutral position (in the direction of arrow C2). Furthermore, when the setting mode is enabled, the steering selector switch 52 sets the start point of the driving reference line by swinging backward from the neutral position (in the direction of arrow D1), and sets the end point of the driving reference line by swinging forward from the neutral position (in the direction of arrow D2).

[0066] As shown in FIGS. 11 to 13, the correction switch 53 is disposed on the other side (right side) of the steering shaft 31 in the vehicle body width direction. The correction switch 53 is also disposed rearward of the steering shaft 31 in the front-rear direction. That is, the correction switch 53 is disposed to the right and rear (diagonally rear right) of the steering shaft 31. In this embodiment, the correction switch 53 is configured as a push switch. In terms of its position relative to the column cover 79, the correction switch 53 is disposed to the right and rear (diagonally rear right) of the column cover 79. In terms of its position relative to the mounting surface 78f of the panel cover 78, the correction switch 53 is disposed rearward of the second region 78f2 of the mounting surface 78f.

[0067] Furthermore, in terms of its positional relationship with the display device 45, the correction switch 53 is disposed behind the display device 45 (on the driver's seat 10 side). This allows the driver to easily and accurately operate the correction switch 53 while checking the display device 45, without changing his / her posture seated in the driver's seat 10. 13, the correction switch 53 does not overlap with the grip 30a of the steering handle 30 when viewed from the axial direction of the steering shaft 31. Specifically, the correction switch 53 is arranged inside the grip 30a of the steering handle 30 (on the side closer to the axis of the steering shaft 31) when viewed from the axial direction of the steering shaft 31.

[0068] The screen changeover switch 54 changes the display of the display device 45 to show the operating status (operating 27 shows an example of the first screen Q1 and the second screen Q2 displayed on the display device 45. As shown in FIGS. 12 and 13 , the screen changeover switch 54 is disposed on the other side (right side) of the steering shaft 31 in the vehicle body width direction. Furthermore, the screen changeover switch 54 is disposed in front of the steering shaft 31 in the front-rear direction. That is, the screen changeover switch 54 is disposed to the right and in front (diagonally forward right) of the steering shaft 31. In this embodiment, the screen changeover switch 54 is configured as a push switch. In terms of its position relative to the column cover 79, the screen changeover switch 54 is disposed to the right and in front (diagonally forward right) of the column cover 79. In terms of its position relative to the mounting surface 78f of the panel cover 78, the screen changeover switch 54 is disposed in a front portion of a second region 78F of the mounting surface 78f. Furthermore, the screen changeover switch 54 is located in front of the correction switch 53.

[0069] 13, the screen changeover switch 54 does not overlap with the grip 30a of the steering handle 30 when viewed from the axial direction of the steering shaft 31. Specifically, the screen changeover switch 54 is arranged inside the grip 30a of the steering handle 30 (on the side closer to the axis of the steering shaft 31) when viewed from the axial direction of the steering shaft 31.

[0070] As described above, the setting switch 51, steering changeover switch 52, correction switch 53, and screen changeover switch 54 are arranged together 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.

[0071] 12 and 13, a combination switch 82 is provided on the mounting surface 78f of the panel cover 78. The combination switch 82 is a switch that operates turn signals, headlights, and the like that are provided on the front of the vehicle body 3. The combination switch 82 is arranged around the steering shaft 31. Specifically, the combination switch 82 is arranged on one side (left side) of the steering shaft 31. In relation to the column cover 79, the combination switch 82 is arranged on one side (left side) of the column cover 79. The combination switch 82 is also arranged below the steering selector switch 52 and in front of the setting switch 51.

[0072] 13, the combination switch 82 does not overlap with the grip 30a of the steering handle 30 when viewed in the axial direction of the steering shaft 31. Specifically, the combination switch 82 is located inside the grip 30a of the steering handle 30 (on the side closer to the axis of the steering shaft 31) when viewed in the axial direction of the steering shaft 31.

[0073] It should be noted that the positions of the various switches described above may be reversed between left and right. That is, one side may be positioned on the left and the other side on the right, or one side may be positioned on the right and the other side on the left. Specifically, for example, the setting switch 51 and the steering changeover switch 52 may be positioned on the right side of the steering shaft 31, and the correction switch 53 may be positioned on the left side of the steering shaft 31. <Lift lever (pump lever), accelerator lever> As shown in FIGS. 11 to 13, the tractor 1 is provided with a lift lever 83 and an accelerator lever 84.

[0074] The lifting lever 83 is a lever (pump lever) that raises and lowers the connecting part 8. The lifting lever 83 is arranged on the other side (right side) of the steering shaft 31. The lifting lever 83 can swing around a base end provided on the steering shaft 31 side as a fulcrum. The base end of the lifting lever 83 is provided inside the panel cover 78. The lifting lever 83 protrudes from the other side (right side) of the panel cover 78 and extends upward, with its tip end located on the other side (right side) of the column cover 79.

[0075] 13, when the lift lever 83 is in the neutral position, it is located between the correction switch 53 and the screen changeover switch 54 when viewed from the axial direction of the steering shaft 31, and does not overlap with the correction switch 53 or the screen changeover switch 54. This prevents the correction switch 53 and the screen changeover switch 54 from being operated unintentionally when operating the lift lever 83, and prevents the lift lever 83 from being operated unintentionally when operating the correction switch 53 and the screen changeover switch 54.

[0076] 12 and 13, a grip 83a to be gripped by an operator is provided at the tip (right end) of the lift lever 83. The grip 83a is located below and in the vicinity of the grip 30a of the steering handle 30. As shown in FIG. 13, the grip 83a overlaps with the grip 30a when viewed from the axial direction of the steering shaft 31. This allows the operator to operate the lift lever 83 by reaching out to the grip 83a while gripping the grip 30a of the steering handle 30.

[0077] The lift lever 83 is disposed on the opposite side of the steering selector switch 52 in the vehicle width direction, across the steering shaft 31. This prevents erroneous operation caused by the operator's hand touching the lift lever 83 when operating the steering selector switch 52, or the operator's hand touching the steering selector switch 52 when operating the lift lever 83. As shown in FIGS. 11 to 13, the accelerator lever 84 is disposed on the other side (right side) of the steering shaft 31. The accelerator lever 84 is swingable around a base end portion provided on the steering shaft 31 side as a fulcrum. The base end portion of the accelerator lever 84 is provided inside the panel cover 78. The accelerator lever 84 protrudes upward from the mounting surface 78f of the panel cover 78 on the other side of the column cover 79. More specifically, the accelerator lever 84 protrudes from the mounting surface 78f of the panel cover 78 in front of the correction switch 53 and behind the screen changeover switch 54. The accelerator lever 84 protrudes upward from the mounting surface 78f and then extends to the right (in a direction away from the column cover 79).

[0078] A grip portion 84a that is gripped by the operator is provided at the tip (right end) of the accelerator lever 84. The grip portion 84a is located below the grip 30a of the steering handle 30. As shown in FIG. 13, the grip portion 84a overlaps with the grip 30a in the axial direction of the steering shaft 31. The grip portion 84a of the accelerator lever 84 is located in front of and below the grip portion 83a of the lift lever 83. <Automatic steering mechanism placement, etc.> Next, the arrangement of the automatic steering mechanism 37 will be described.

[0079] As shown in Figures 10 and 15 to 17, the steering motor 38 of the automatic steering mechanism 37 is disposed around the steering shaft 31. Specifically, the steering motor 38 is disposed below the steering handle 30, in front of and to the right (diagonally forward right) of the steering shaft 31. The output shaft (rotation shaft) of the steering motor 38 is disposed parallel to the axial direction of the steering shaft 31 and extends downward.

[0080] The gear mechanism 39 of the automatic steering mechanism 37 has a gear case 39a and a plurality of gears housed inside the gear case 39a. As shown in FIGS. 10 and 15, the gear case 39a is fixed to the upper end of a support post 85. The support post 85 is formed in a rectangular cylindrical shape and extends in the axial direction of the steering shaft 31. As shown in FIGS. 15 and 17, an upper plate 85a that supports the gear case 39a from below is provided at the upper end of the support post 85. Note that in FIG. 17, the gear case 39a is omitted to show the internal gears. As shown in Fig. 17, the lower part of the steering shaft 31 that passes through the upper plate 85a and the gear case 39a is inserted into the upper part of the support post 85. As shown in Figs. 8 to 10 and 15, the lower end part of the support post 85 is fixed to the upper part of the clutch housing 72 via a mounting stay 86 or the like.

[0081] The steering motor 38 and the gear mechanism 39 are provided integrally. Specifically, the housing of the steering motor 38 is fixed to the upper part of the gear case 39a by bolts or the like. 10, the steering motor 38 and the gear mechanism 39 are disposed near the axis CL1 of the steering shaft 31. More specifically, the steering motor 38 and the gear mechanism 39 are disposed in a position, in the vehicle body width direction, closer to the axis CL1 of the steering shaft 31 than the outer edge of the grip 30a of the steering handle 30. In other words, the steering motor 38 and the gear mechanism 39 are disposed, in the vehicle body width direction, between an imaginary line VL1 extending downward from the outer end of one lateral side in the vehicle body width direction of the grip 30a, and an imaginary line VL2 extending downward from the outer end of the other lateral side in the vehicle body width direction of the grip 30a.

[0082] As shown in Figures 17 and 18, the gear mechanism 39 has a first gear 391, a second gear 392, a third gear 393, and a fourth gear 394. The first gear 391 is attached to the output shaft (rotation shaft) of the steering motor 38. The second gear 392 is disposed in front of the steering shaft 31 and meshes with the first gear 391. The third gear 393 is disposed below the second gear 392 and is connected to the second gear 392 by a connecting shaft 390. The connecting shaft 390 is rotatably supported by a bearing 395 held in the gear case 39a. The second gear 392 and the third gear 393 rotate integrally with the connecting shaft 390. The fourth gear 394 meshes with the third gear 393. The fourth gear 394 is attached to the steering shaft 31 and rotates together with the steering shaft 31.

[0083] When the steering motor 38 is driven and the output shaft rotates, the power of the rotation is transmitted from the first gear 391 to the second gear 392, causing the connecting shaft 390 to rotate. When the connecting shaft 390 rotates, the third gear 393 rotates, and the power of the rotation is transmitted to the steering shaft 31 via the fourth gear 394, causing the steering shaft 31 to rotate. In this way, the steering shaft 31 rotates when the steering motor 38 is driven. <Power steering device placement, etc.> Next, the arrangement of the power steering device 32 will be described.

[0084] As shown in FIGS. 7 and 17 , the steering shaft 31 is connected to the control valve 34 of the power steering device 32 via a linkage mechanism (universal joints 87, 88, 89 and arms 90, 91, 92). Specifically, the lower part of the steering shaft 31 is connected to one end of a first arm 90 via a first universal joint 87. The other end of the first arm 90 is connected to one end of a second arm 91 via a second universal joint 88. The other end of the second arm 91 is connected to one end of a third arm 92 via a third universal joint 89. The other end of the third arm 92 is connected to a power steering unit 93 including the control valve 34. Note that the configuration of the power steering device 32 shown in FIG. 7 is partially different from the configuration shown in FIG. 1 , but either configuration or another configuration may be adopted.

[0085] The power steering unit 93 shown in FIG. 7 includes a control valve 34 and a steering cylinder (power cylinder) 35. The power steering unit 93 (control valve 34, steering cylinder 35) is supported by the front axle frame 70. The power steering unit 93 is located between the first frame 70A and the second frame 70B of the front axle frame 70. The power steering unit 93 is connected to the hydraulic pump 33 via a hydraulic hose (not shown). The hydraulic pump 33 is located behind the power steering unit 93 and above the second frame 70B of the front axle frame 70. The hydraulic pump 33 is driven by the power of the prime mover 4.

[0086] The steering cylinder 93 is connected to one end (inner end) of the left and right tie rods 95 via a pitman arm 94. The other end (outer end) of the tie rod 95 is connected to the left and right front wheels 7F. When the steering wheel 30 is manually rotated (steered), this rotation is transmitted from the steering shaft 31 via a linkage mechanism (universal joints 87, 88, 89 and arms 90, 91, 92) to the power steering unit 93, causing the control valve 34 to operate (the spool to move). As a result, hydraulic oil discharged from the hydraulic pump 33 is sent to the steering cylinder 35, driving the steering cylinder 35. The driving force of the steering cylinder 35 is transmitted to the tie rod 95 via the pitman arm 94, and the movement of the tie rod 95 changes the direction of the left and right front wheels 7F.

[0087] As shown in Figure 28, the power steering unit 93 (control valve 34, steering cylinder 35) and hydraulic pump 33 that constitute the power steering device 32 are disposed outside the panel cover 78 (in front of the panel cover 78). On the other hand, as shown in Figures 8, 9, etc., the automatic steering mechanism 37 (steering motor 38, gear mechanism 39) is disposed inside the panel cover 78. In this way, the automatic steering mechanism 37 (steering motor 38, gear mechanism 39) and the power steering device 32 are disposed at positions separated from each other.

[0088] If the automatic steering mechanism 37 and the power steering device 32 (e.g., the control valve 34) are located close to each other, a large, concentrated installation space is required. However, by locating the automatic steering mechanism 37 and the power steering device 32 at separate locations, the installation space for each can be small, and a large, concentrated installation space is not required. <Layout of the first control device and the second control device> As shown in Figures 8 and 9, the first control device 60A and the second control device 60B are disposed inside the panel cover 78. As shown in Figures 10 and 16, the first control device 60A is disposed on one side (left side) of the steering shaft 31. The second control device 60B is disposed on the other side (right side) of the steering shaft 31. The first control device 60A and the second control device 60B are connected by a harness (not shown) capable of transmitting electrical signals.

[0089] In this way, the first control device 60A and the second control device 60B are configured separately and arranged separately on one side (left) and the other side (right) of the steering shaft 31, so that the first control device 60A and the second control device 60B are smaller in size than if they were an integrated control device, and can be arranged in the vicinity of the steering shaft 31. Therefore, the first control device 60A and the second control device 60B can be reliably housed within the panel cover 78. Furthermore, because the first control device 60A and the second control device 60B are arranged apart, it is possible to prevent the heat generated by one control device from adversely affecting the other control device.

[0090] The first control device 60A and the second control device 60B each have a housing and a circuit board disposed within the housing. The circuit board is composed of various electrical and electronic components such as semiconductors and is capable of performing the above-described controls. The housing is rectangular and disposed vertically. Specifically, the housing of the first control device 60A has three sides (length, width, and height), the shortest side of which faces the vehicle width direction and the longest side of which faces the up-down direction. The housing of the second control device 60B has three sides, the shortest side of which faces approximately the vehicle width direction and the longest side of which faces approximately the front-to-rear direction. In this way, the shortest sides of the first control device 60A and the second control device 60B face the vehicle width direction or approximately the vehicle width direction. This reduces the area occupied by the first control device 60A and the second control device 60B in the vehicle width direction, allowing the first control device 60A and the second control device 60B to be securely accommodated within the panel cover 78. Also, since the panel cover 78 can be made smaller, it is possible to ensure sufficient legroom and forward visibility for the driver seated in the driver's seat 10. Furthermore, since the first control device 60A and the second control device 60B can be arranged close to each other, the harness connecting the first control device 60A and the second control device 60B can be shortened, making them less susceptible to noise.

[0091] 10, the first control device 60A is disposed in a position in the vehicle width direction closer to the axis CL1 of the steering shaft 31 than the outer edge of the grip 30a of the steering handle 30. In other words, the first control device 60A is disposed in a position closer to the axis CL1 than an imaginary line VL1 extending downward from the outer end of one lateral side in the vehicle width direction of the grip 30a of the steering handle 30. The second control device 60B overlaps with an imaginary line VL2 extending downward from the outer end of the other lateral side in the vehicle width direction of the grip 30a of the steering handle 30.

[0092] The second control device 60B is disposed below the first control device 60A. The second control device 60B is also disposed below the steering motor 38. In other words, the second control device 60B is disposed at a position shifted downward with respect to the first control device 60A and the steering motor 38. This prevents the second control device 60B from being adversely affected by heat generated by the first control device 60A and the steering motor 38.

[0093] 10, the second control device 60B and the steering motor 38 are disposed to the right of the axis CL1 of the steering shaft 31. In this way, the second control device 60B and the steering motor 38 are disposed in the same direction (right) in the vehicle body width direction, so that the second control device 60B is located near the steering motor 38. This allows the harness electrically connecting the second control device 60B and the steering motor 38 to be shortened, making it less susceptible to noise.

[0094] As shown in FIGS. 7, 10, and 15 to 17, the first control device 60A and the second control device 60B are held by a holding member 96. The holding member 96 has a first holding portion 96a, a second holding portion 96b, and a connecting portion 96c. The first holding portion 96a is disposed on one side (left) of the steering shaft 31. The first control device 60A is fixed and held to the first holding portion 96a by fasteners such as bolts. The second holding portion 96b is disposed on the other side (right) of the steering shaft 31. The second control device 60B is fixed and held to the second holding portion 96c by fasteners such as bolts. The connecting portion 96c extends in the vehicle width direction from one side (left) to the other side (right) of the steering shaft 31. The connecting portion 96c connects the first holding portion 96a and the second holding portion 96b.

[0095] 16, the holding member 96 (first holding portion 96a) supports the first control device 60A on one side (left) of the steering shaft 31 and gear case 39a in a plan view. The holding member 96 (second holding portion 96b) supports the second control device 60B on one side (left) of the steering shaft 31 and gear case 39a in a plan view. The holding member 96 (second holding portion 96b) also supports the second control device 60B so that it moves to one side (left) from the front end to the rear end. This allows the space 200A between the connector side (front side) of the gear case 39a and the second control device 60B to be wider, making it easier to route wiring, etc.

[0096] Also, as shown in Figure 10, when the first control device 60A and the second control device 60B are viewed with the gear case 39a as a reference, the retaining member 96 supports the first control device 60A above the gear case 39a and supports the second control device 60B below the gear case 39a. An intermediate portion of the coupling portion 96c of the holding member 96 in the vehicle width direction is fixed to a connecting member 97 by welding or the like. The connecting member 97 extends in the front-rear direction. As shown in FIG. 15 , the connecting member 97 extends forward and rearward from the coupling portion 96c. The rear end of the connecting member 97 is fixed to an upper portion of the support post 85. The front end of the connecting member 97 is connected to the rear end of a stay 98 that extends in the front-rear direction.

[0097] 16 and 17, the connecting member 97 is made up of a plate member and has a front plate portion 97a to which the coupling portion 96c is attached and which extends forward from the coupling portion 96c, a rear plate portion 97b to which the coupling portion 96c is attached and which extends rearward (toward the steering shaft 31) from the coupling portion 96c, a first plate portion 97c extending from the rear plate portion 97b toward the first control device 60A, and a second plate portion 97d extending from the rear plate portion 97b toward the second control device 60B. The first plate portion 97c and the second plate portion 97d are integrally formed and inclined downward toward the steering shaft 31. The rear ends of the first plate portion 97c and the second plate portion 97d are attached to the support post 85.

[0098] The front end of the stay 98 is fixed to the upper part of a partition plate 99. As shown in Figures 8 and 9, the partition plate 99 is disposed inside the bonnet 76 and divides the space inside the bonnet 76 into a first space S1 at the front and a second space S2 at the rear. The prime mover 4 is disposed in the first space S1. A fuel tank (not shown) is disposed in the second space S2. The lower part of the partition plate 99 is fixed to the upper part of the clutch housing 72. <Location of receiving device, etc.> Next, the arrangement of the receiving device 41 that constitutes the position detection device 40 will be described.

[0099] The receiving device 41 receives signals from positioning satellites and detects the position of the vehicle body 3 based on the received signals. That is, the receiving device 41 is a device that detects position information of the vehicle body 3 using a satellite positioning system (GNSS: Global Navigation Satellite System). As the satellite positioning system, for example, a GPS (Global Positioning System) is used. For example, the receiving device 41 receives signals transmitted from positioning satellites and signals transmitted from base stations installed on the ground, and calculates the position of the vehicle body 3 based on the received signals. Specifically, the base station transmits correction information including the position information of the base station (reference position) and information obtained from the signals from the positioning satellites (such as the distance between the satellite and the receiver) to the receiving device 41 via wireless communication or the like. The receiving device 41 corrects the information received from the positioning satellites based on the correction information obtained from the base station to obtain position information with higher accuracy. However, other methods such as an RTK system may be used as a method for detecting the vehicle body position by the receiving device 41.

[0100] As shown in FIGS. 28 and 29, the receiving device 41 is attached to a ROPS 61. Before explaining the installation position of the receiving device 41, the specific configuration of the ROPS 61 will be explained. The ROPs 61 is provided behind the driver's seat 10. The ROPs 61 has a first vertical pillar portion 61a, a second vertical pillar portion 61b, and a horizontal portion 61c. The first vertical pillar portion 61a, the second vertical pillar portion 61b, and the horizontal portion 61c are integrally formed by bending a square pipe. The first vertical pillar portion 61a extends in the vertical direction to the left and rear of the driver's seat 10. The second vertical pillar portion 61b extends in the vertical direction to the right and rear of the driver's seat 10. The horizontal portion 61c extends in the vehicle width direction and is located above the first vertical pillar portion 61a above and rear of the driver's seat 10. The upper end of the first vertical pillar 61a is connected to the upper end of the second vertical pillar 61b. As a result, the ROPs 61 is formed in a generally gate-like shape when viewed from the front. The ROPs 61 can swing rearward around pivot shafts 102 provided at the lower ends of the first vertical pillar 61a and the second vertical pillar 61b.

[0101] The receiving device 41 is attached to the horizontal section 61c of the ROPS 61. The receiving device 41 is fixed to a bracket 103, which is attached to the cross-bridge portion 61c. The bracket 103 is attached to the center of the cross-bridge portion 61c in the vehicle width direction and extends rearward from the center. As a result, the receiving device 41 is located rearward of the center of the cross-bridge portion 61c in the vehicle width direction. In this way, the receiving device 41 is disposed in a position offset (displaced) rearward from the ROPS 61. The receiving device 41 is also located above and behind the driver's seat 10.

[0102] However, the mounting position of the receiving device 41 is not limited to the positions shown in Figures 28 and 29. For example, the receiving device 41 may be positioned offset forward or to the side from the ROPs 61. The receiving device 41 may also be mounted on the first vertical pillar portion 61a or the second vertical pillar portion 61b of the ROPs 61, or may be mounted at a location other than the ROPs 61 on the tractor 1. A canopy may also be used instead of the ROPs 61, and the receiving device 41 may be mounted on the canopy. <Inertial measurement device placement, etc.> Next, the arrangement of the inertial measurement unit 42 that constitutes the position detection device 40 will be described.

[0103] The inertial measurement unit 42 is a device that measures the inertia of the vehicle body 3. Specifically, the inertial measurement unit 42 can measure the inertia (inertial information) of the vehicle body 3, such as the yaw angle, pitch angle, and roll angle. 19, 20, 28, and 29, the inertial measurement unit 42 is disposed below the driver's seat 10 and on the center line CL2 in the vehicle width direction. The inertial measurement unit 42 is disposed in a position overlapping with the rear wheel 7R in a side view.

[0104] The inertial measurement unit 42 is disposed above the transmission case 74. In other words, the inertial measurement unit 42 is disposed at a position overlapping the transmission case 74 in a plan view. Since the inertial measurement unit 39 is disposed at a position overlapping the transmission case 10, the position of the inertial measurement unit 39 is close to the center of gravity of the vehicle body 3. This makes it easier for the inertial measurement unit 39 to measure a representative value of the attitude change of the vehicle body 3 (a value that can represent the attitude change of the vehicle body 3), and the position of the vehicle body 3 can be determined quickly and accurately by following the attitude change of the vehicle body 3. In other words, the inertial measurement unit 39 is disposed at a position on the vehicle body 3 that provides good weight balance in the front-to-rear, left-to-right, and height directions, thereby improving the measurement accuracy of the position of the vehicle body 3.

[0105] 20, the inertial measurement unit 42 is disposed on the axis CL3 of the rear axle in a plan view. When a working implement is attached to the connecting portion 8, the center of gravity of the body 2 and the working implement is closer to the axis CL3 of the rear axle than to the center of the body 2 in the longitudinal direction. Therefore, by disposing the inertial measurement unit 42 on the axis CL3 of the rear axle, even when a working implement is attached to the connecting portion 8, the inertial measurement unit 39 is closer to the center of gravity of the body 3, so that the position of the body 3 can be determined quickly and accurately.

[0106] The support structure (mounting structure) of the inertial measurement unit 42 will be described below mainly with reference to FIGS. The inertial measurement unit 42 is supported on the vehicle body 3 (transmission case 74) by a support member 65 via a vibration-isolating member 64. The vibration-isolating member 64 is a member that suppresses vibration of the inertial measurement unit 42, and is an elastically deformable member such as rubber or a spring.

[0107] The support member 65 supports the inertial measurement unit 42 on the vehicle body 3 via the vibration-isolating member 64. More specifically, the support member 65 supports the inertial measurement unit 42 on a housing that covers a drive unit that drives the vehicle body 3 via the vibration-isolating member 64. The drive unit is the prime mover 4 or a device that transmits the power of the prime mover 4. In the present embodiment, the drive unit is the transmission 5, and the housing is the transmission case 74. However, the housing on which the support member 65 is supported is not limited to the transmission case 74, and the drive unit covered by the housing is not limited to the transmission 5. For example, the housing may be a clutch housing 72, and the drive unit may be a clutch. The following description will be given assuming that the drive unit is the transmission 5 and the housing is the transmission case 74.

[0108] The support member 65 is attached to a support plate 66. The support plate 66 is attached to a transmission case (housing) 74. In other words, the support member 65 is indirectly attached to the transmission case 74 via the support plate 66. However, the support member 65 may also be attached directly to the transmission case (housing) 74 (without via the support plate 66). The support plate 66 is disposed below the driver's seat 10 and supports the driver's seat 10 from below. A support bracket 100 and a cushion material 101 are attached to the upper surface of the support plate 66. The support brackets 100 are fixed to the left and right front portions of the support plate 66 by welding or the like, and extend forward from the support plate 66. In this embodiment, the support bracket 100 is made of an angle material with an L-shaped cross section. The cushion material 101 is made of an elastic material such as rubber. In this embodiment, the cushion material 101 is cylindrical. The cushion material 101 is fixed to the left and right rear portions of the support plate 66 by bolts or the like. The driver's seat 10 is supported above the support plate 66 by being placed on the upper parts of the support bracket 100 and the cushion material 101.

[0109] The support plate 66 is attached to the upper part of the transmission case 74. As shown in Figures 19, 22, etc., the transmission case 74 has a protrusion 74a that protrudes upward from the top surface of the transmission case 74. The protrusion 74a includes a front protrusion 74a1 that protrudes upward from the front of the transmission case 74 and a rear protrusion 74a2 that protrudes upward from the rear of the transmission case 74. The front protrusion 74a1 and the rear protrusion 74a2 are arranged at intervals in the front-to-rear direction and each extend in the vehicle body width direction. The front protrusion 74a1 and the rear protrusion 74a2 each have a screw hole 74b that extends in the up-down direction. A plurality of screw holes 74b are formed in each of the front protrusion 74a1 and the rear protrusion 74a2, spaced apart in the vehicle body width direction. In this embodiment, two screw holes 74b are formed in the front protruding portion 74a1 and two screw holes 74b are formed in the rear protruding portion 74a2 (four screw holes in total).

[0110] The support plate 66 has a first through hole 66a and a second through hole 66b. The first through holes 66a are holes for attaching the support plate 66 to the transmission case 74. As shown in FIGS. 19, 21, and 22, the first through holes 66a are formed at positions corresponding to the multiple screw holes 74b formed in the transmission case 74. Specifically, the first through holes 66a include a front through hole 66a1 and a rear through hole 66a2. The front through holes 66a1 are formed in the left front and right front portions of the support plate 66. The rear through holes 66a2 are formed in the left rear and right rear portions of the support plate 66. A bolt B1 is inserted through the first through hole 66a, and the bolt B1 is screwed into the screw hole 74b, thereby fixing the support plate 66 to the upper part of the transmission case 74.

[0111] As described above, the transmission case 74 constitutes a highly rigid body frame by being integrally connected to the front axle frame 70, the flywheel housing 71, the clutch housing 72, and the intermediate frame 73. Therefore, by being fixed to the transmission case 74, the support plate 66 is fixed to the highly rigid body frame. The second through-holes 66b are holes for attaching the support member 65 to the support plate 66. As shown in FIGS. 21 and 24, the second through-holes 66b are provided at a position closer to the rear of the support plate 66. More specifically, the second through-holes 66b are provided rearward of the front through-holes 66a1 and forward of the rear through-holes 66a2. The second through-holes 66b include a first through-hole 66b1 provided on one side (left) in the vehicle body width direction and a second through-hole 66b2 provided on the other side (right) in the vehicle body width direction. The first through-hole 66b1 and the second through-hole 66b2 are provided at symmetrical positions across the center line CL2 in the vehicle body width direction.

[0112] A first female threaded member 691 and a second female threaded member 692 are fixed to the upper surface of the support plate 66. The first female threaded member 691 is provided above one through hole 66b1. The second female threaded member 692 is provided above the other through hole 66b2. The threaded hole of the first female threaded member 691 communicates with one through hole 66b1. The threaded hole of the second female threaded member 692 communicates with the other through hole 66b2. Note that the first female threaded member 691 and the second female threaded member 692 can be omitted by forming threaded holes directly in the support plate 66.

[0113] 21, 24, etc., the support member 65 has an attachment portion 65a and a fixing portion 65b. The attachment portion 65a and the fixing portion 65b are integrally formed by bending a single plate (such as a metal plate). The mounting portion 65a is disposed below the support plate 66. The mounting portion 65a is flat and disposed parallel to the support plate 66. The inertial measurement unit 42 is attached to the mounting portion 65a. More specifically, the inertial measurement unit 42 is placed on the upper surface of the mounting portion 65a and fixed to the upper surface by mounting fixtures (bolt B2 and nut N1).

[0114] The fixed portion 65b rises from the mounting portion 65a. Specifically, the fixed portion 65b includes a first fixed portion 65b1 provided on the left side of the support member 65a and a second fixed portion 65b2 provided on the right side of the support member 65a. The first fixed portion 65b1 has a first upright portion 62 rising from the left end of the mounting portion 65a and a first upper plate portion 67 extending leftward from the upper end of the first upright portion 62. The second fixed portion 65b2 has a second upright portion 63 rising from the right end of the mounting portion 65a and a second upper plate portion 68 extending rightward from the upper end of the second upright portion 63. The upper surfaces of the first upper plate portion 67 and the second upper plate portion 68 are disposed at the same height and parallel to the upper surface of the mounting portion 65a.

[0115] As shown in FIGS. 24 and 25, a first mounting hole 67a is formed in the first upper plate portion 67. A second mounting hole 68a is formed in the second upper plate portion 68. The first mounting hole 67a and the second mounting hole 68a are through holes extending in the up-down direction. The first mounting hole 67a is positioned so as to overlap with the first through hole 66b1. The second mounting hole 68a is positioned so as to overlap with the other through hole 66b2. A bolt B3 is inserted into each of the first mounting hole 67a and the second mounting hole 68a. The bolt B3 inserted into the first mounting hole 67a passes through the one through hole 66b1 and is screwed into the threaded hole of the first female threaded member 691. The bolt B3 inserted into the second mounting hole 68a passes through the other through hole 66b2 and is screwed into the threaded hole of the second female threaded member 692. As a result, the fixing portion 65b is fixed to the support plate 66 by the bolt B3.

[0116] As shown in FIGS. 24 and 25, the fixing portion 65b (first fixing portion 65b1, second fixing portion 65b2) is fixed to the support plate 66 via the vibration-damping member 64. The vibration-damping member 64 is made of a substantially cylindrical elastic body (e.g., rubber). As shown in FIG. 25, the vibration-damping member 64 has a first large diameter portion 64a, a second large diameter portion 64b, and a small diameter portion 64c. The first large diameter portion 64a is provided on the upper portion of the vibration-damping member 64. The second large diameter portion 64b is provided on the lower portion of the vibration-damping member 64. The small diameter portion 64c is provided between the first large diameter portion 64a and the second large diameter portion 64b. Note that although FIG. 25 shows the mounting structure of the vibration-damping member 64 at the first fixing portion 65b1, the mounting structure of the vibration-damping member 64 at the second fixing portion 65b2 is similar.

[0117] The first large diameter portion 64a is interposed between the upper surface of the fixing portion 65b (first fixing portion 65b1, second fixing portion 65b2) and the lower surface of the support plate 66. The second large diameter portion 64b is interposed between the lower surface of the fixing portion 65b (first fixing portion 65b1, second fixing portion 65b2) and the head of the bolt B3. The small diameter portion 64c is interposed between the outer peripheral surface of the bolt B3 and the inner peripheral surfaces of the mounting holes (first mounting hole 67a, second mounting hole 68a) of the support member 65. In this way, vibration-proof members 64 are interposed between the bolt B3 and the fixing portion 65b (first fixing portion 65b1, second fixing portion 65b2) and between the fixing portion 65b (first fixing portion 65b1, second fixing portion 65b2) and the support plate 66.

[0118] One or both of the first large diameter portion 64a and the second large diameter portion 64b may be formed by elastic deformation of the vibration-damping member 64 caused by tightening of the bolt B3, or may be formed when the vibration-damping member 64 is not elastically deformed. As described above, the support member 65 supports the inertial measurement unit 42 below the support plate 66 via the vibration isolation member 64 .

[0119] As shown in Figures 20 and 21, the support plate 66 has an opening 66c provided above the inertial measurement unit 42. The inertial measurement unit 42 is exposed through the opening 66c. That is, the inertial measurement unit 42 has a portion located below the support plate 66 and a portion that protrudes above the support plate 66 through the opening 66c. The top surface of the inertial measurement unit 42 is located above the support plate 66, but is separated from the underside of the driver's seat 10 by at least a distance that reliably prevents contact with the underside. The opening 66c also exposes the mounting fixture (nut N1). This allows a hand, tool, or the like to be inserted through the opening 66c to easily remove the mounting fixture. Furthermore, by having the upper portion of the inertial measurement unit 42 protrude from the opening 66c, the space occupied by the inertial measurement unit 42 in the thickness direction (vertical direction) can be reduced.

[0120] The mounting position of the inertial measurement unit 42 is not limited to that in the above embodiment. From the viewpoint of accurately detecting the behavior of the tractor (work vehicle) 1 using the inertial measurement unit 42, there are four main possible positions for mounting the inertial measurement unit 42. The first position is within the region connecting the left front wheel 7FL, the right front wheel 7FR, the left rear wheel 7RL, and the right rear wheel 7RR, and is indicated by the symbol A in FIG. 26. The second position is within the region near the intersection of the diagonal line connecting the left front wheel 7FL and the right rear wheel 7RR and the diagonal line connecting the right front wheel 7FR and the left rear wheel 7RL, and is indicated by the symbol B in FIG. 26. The third position is near the center of gravity of the tractor 1. The fourth position is the range in which the zero moment point (ZMP) moves when the tractor 1 is running (the range in which the center of gravity moves when running (dynamic center of gravity position)), and is indicated by the symbol C in FIG. 26. The range in which the ZMP moves, indicated by the symbol C in FIG. 26, is a stable region in which the posture of the tractor 1 is stable when running (for example, a region in which the tractor 1 runs stably).

[0121] The ZMP can be calculated by providing multiple body state detection units on the body 3. The body state detection units are devices that detect at least the first load (floor reaction force) and moment acting on the body 3, and for example, a six-component load cell that can detect the first load and moment in three axial directions (X-axis, Y-axis, and Z-axis) is used. The X-axis can be set to the traveling direction of the body 3, the Y-axis to the width direction of the body, and the Z-axis to the up-down direction.

[0122] The multiple vehicle body state detection units may include a first state detection unit corresponding to a support point at the left front of the vehicle body 3 (left front wheel), a second state detection unit corresponding to a support point at the right front of the vehicle body 3 (right front wheel), a third state detection unit corresponding to a support point at the left rear of the vehicle body 3 (left rear wheel), and a fourth state detection unit corresponding to a support point at the right rear of the vehicle body 3 (right rear wheel). The ZMP can be calculated by a control device (control device 60 or another control device) (computer). The control device determines the ZMP, which is expressed in two dimensions, based on a first load (floor reaction force) at the support point of the vehicle body 3, for example, the floor reaction force and moment at the first state detection unit, the second state detection unit, the third state detection unit, and the fourth state detection unit.

[0123] In Figure 26, area Q1 connecting support points of the vehicle body 3 (positions where multiple vehicle body state detection units are installed) is a critical area, and is represented two-dimensionally on the X and Y axes. Stable area Q2 (C) is a stable area in which the posture of the tractor 1 is stable while traveling, and is an area shifted inward from the critical area Q1 by a predetermined distance. The area excluding the critical area Q1 and the stable area Q2, i.e., the area between the contour line constituting the critical area Q1 and the contour line constituting the stable area Q2, is an unstable area Q3 that is prone to instability.

[0124] By setting the mounting position of the inertial measurement unit 42 in the stable region Q2(C), the measurement accuracy of the inertial measurement unit 42 can be improved. <Effects> The work vehicle (tractor) 1 of the above embodiment provides the following effects. The work vehicle 1 comprises a steering handle 30, a steering shaft 31 that rotatably supports the steering handle, a vehicle body 3 that can be driven either by manual steering with the steering handle or by automatic steering of the steering handle based on a planned driving line, a setting switch 51 that is arranged around the steering shaft and switches to a setting mode that performs at least settings before the start of automatic steering, and a steering changeover switch 52 that is arranged around the steering shaft and switches between starting and ending automatic steering in the setting mode.

[0125] According to this configuration, since the setting switch 51 and the steering changeover switch 52 are arranged around the steering shaft 31, the driver can reliably recognize the setting switch 51 and the steering changeover switch 52 at a glance and can easily operate them without changing his / her posture. Therefore, unintended automatic steering due to erroneous operation of the switches can be prevented.

[0126] The work vehicle 1 also includes a position detection device 40 that is mounted on the vehicle body 3 and detects the position of the vehicle body based on signals from positioning satellites, and a correction switch 53 that is arranged around the steering shaft 31 and corrects the position of the vehicle body detected by the position detection device. According to this configuration, since the correction switch 53 is also arranged around the steering shaft 31 in addition to the setting switch 51 and steering changeover switch 52, the driver can reliably recognize the setting switch 51, steering changeover switch 52, and correction switch 53 at a glance and can easily operate them without changing his / her posture. Therefore, unintended automatic steering due to erroneous operation of the switches can be prevented.

[0127] The work vehicle 1 also includes a display device 45 that is arranged around the steering shaft 31 and displays driving information, and a screen changeover switch 54 that is arranged around the steering shaft and selectively switches the display on the display device between a first screen G1 that displays the driving status in the setting mode and a second screen Q2 that explains the setting operations in the setting mode. According to this configuration, in addition to the setting switch 51, steering changeover switch 52, and correction switch 53, the screen changeover switch 54 is also arranged around the steering shaft 31, so the driver can reliably recognize the setting switch 51, steering changeover switch 52, correction switch 53, and screen changeover switch 54 at a glance and can easily operate them without changing his / her posture. Therefore, unintended automatic steering due to erroneous switch operation can be prevented.

[0128] The setting switch 51 is disposed on one side of the steering shaft 31, and the correction switch 53 is disposed on the other side of the steering shaft 31. According to this configuration, the setting switch 51 and the correction switch 53 are arranged in opposite directions across the steering shaft 31, which makes it possible to effectively utilize the space around the steering shaft 31 and prevents the setting switch 51 and the correction switch 53 from being operated erroneously.

[0129] The steering changeover switch 52 is disposed on one side of the steering shaft 31. According to this configuration, the steering changeover switch 52 and the setting switch 51 are arranged on the same side of the steering shaft 31, so that the operability of the switches for automatic steering of the work vehicle 1 is improved.

[0130] The setting switch 51 is disposed on one side of the steering shaft 31, and the screen changeover switch 54 is disposed on the other side of the steering shaft 31. According to this configuration, the setting switch 51 and the screen changeover switch 54 are arranged in opposite directions across the steering shaft 31, which makes it possible to effectively utilize the space around the steering shaft 31 and prevents the setting switch 51 and the screen changeover switch 54 from being operated erroneously.

[0131] A panel cover 78 is provided below the steering wheel 30 to support the display device 45, and the setting switch 51, correction switch 53, and screen changeover switch 54 are provided on the panel cover. According to this configuration, the setting switch 51, the correction switch 53, and the screen changeover switch 54 are all arranged on the panel cover 78 that supports the display device 45. This allows the driver to see the setting switch 51, the correction switch 53, and the screen changeover switch 54 along with the display device 45, improving operability. Furthermore, since the setting switch 51, the correction switch 53, and the screen changeover switch 54 are arranged at positions away from the steering wheel 30, it is possible to prevent the driver from unintentionally touching the setting switch 51, the correction switch 53, or the screen changeover switch 54 when operating the steering wheel 30, or from unintentionally touching the steering wheel 30 when operating the setting switch 51, the correction switch 53, or the screen changeover switch 54. This makes it possible to prevent unintentional switching to automatic steering due to erroneous operation, etc.

[0132] The work vehicle 1 also has a connecting part 8 provided at the rear of the vehicle body 3 to which a work device is connected, and a lifting lever 83 for raising and lowering the connecting part 8, the lifting lever being arranged on the other side of the steering shaft 31. According to this configuration, the lift lever 83 and the steering selector switch 52 are arranged in opposite directions with the steering shaft 31 in between, making it possible to effectively utilize the space around the steering shaft 31. Also, it is possible to prevent operations that the driver does not intend, such as contacting the steering selector switch 52 when operating the lift lever 83, or contacting the lift lever 83 when operating the steering selector switch 52.

[0133] The setting switch 51 and the correction switch 53 are disposed behind the steering shaft 31. According to this configuration, the setting switch 51 and the correction switch 53 are located on the driver's side who operates the steering wheel 30, which improves the operability of the setting switch 51 and the correction switch 53 and makes it less likely that an incorrect operation will occur.

[0134] The work vehicle 1 also includes a steering wheel 30, a steering shaft 31 that rotatably supports the steering wheel 30, a vehicle body 3 that can be driven either by manual steering with the steering wheel or by automatic steering of the steering wheel based on the planned driving line, a position detection device 40 that is provided on the vehicle body and detects the position of the vehicle body based on signals from positioning satellites, an automatic steering mechanism 37 that automatically steers the steering wheel based on the position of the vehicle body detected by the position detection device, a first control device 60A that is arranged on one side of the steering shaft and outputs a control signal calculated based on the position of the vehicle body detected by the position detection device, and a second control device 60B that is arranged on the other side of the steering shaft and controls the automatic steering mechanism based on the control signal output by the first control device so that the vehicle body drives along the planned driving line.

[0135] According to this configuration, the control devices are smaller than when the first control device 60A and the second control device 60B are integrated into one control device. Therefore, the control devices (first control device 60A and second control device 60B) can be arranged in a small space near the steering shaft 31. Furthermore, since the first control device 60A and the second control device 60B are arranged in opposite directions across the steering shaft 31, it is possible to prevent heat generated by one control device from adversely affecting the other control device.

[0136] The work vehicle 1 also includes a display device 45 that is arranged around the steering shaft 31 and displays driving information, and a panel cover 78 that supports the display device below the steering handle 30, and the first control device 60A and the second control device 60B are arranged within the panel cover 78. According to this configuration, the first control device 60A and the second control device 60B are disposed inside the panel cover 78 in a state where they are disposed in the vicinity of the steering shaft 41, which allows the panel cover 78 to be made smaller. As a result, sufficient foot space and forward visibility for the driver can be secured.

[0137] The work vehicle 1 also includes a steering wheel 30, a steering shaft 31 that rotatably supports the steering wheel, a vehicle body 3 that can be driven either by manual steering with the steering wheel or by automatic steering of the steering wheel based on the planned driving line, a position detection device 40 that is provided on the vehicle body and detects the position of the vehicle body based on signals from a positioning satellite, a power steering device 32 that assists in manual operation of the steering wheel, and an automatic steering mechanism 37 that is arranged in a position separate from the power steering device and automatically steers the steering wheel based on the position of the vehicle body detected by the position detection device.

[0138] According to this configuration, the power steering device 32 and the automatic steering mechanism 37 are located at separate locations, so that the operation of the power steering device 32 and the operation of the automatic steering mechanism 37 are independent of each other, and the power steering device 32 can be operated regardless of whether the automatic steering mechanism 37 is operating or not. The work vehicle 1 also has a display device 45 that is arranged around the steering shaft 31 and displays driving information, a panel cover 78 that supports the display device below the steering handle, and front wheels 7F and rear wheels 7R that support the vehicle body 3 so that it can travel, the vehicle body has a front axle frame 72 that supports the front wheels, the automatic steering mechanism is arranged within the panel cover, and the power steering device has a hydraulic pump 33, a control valve 34 to which hydraulic oil discharged from the hydraulic pump is supplied, and a steering cylinder 35 that is operated by the control valve, and the control valve is supported by the front axle frame 72.

[0139] According to this configuration, the automatic steering mechanism 37 can be disposed inside the panel cover 78 near the steering shaft 31 without increasing the size of the panel cover 78. As a result, sufficient foot space and forward visibility can be secured for the driver. The work vehicle 1 also includes a steering handle 30, a steering shaft 31 that rotatably supports the steering handle, a vehicle body 3 that can travel either by manual steering with the steering handle or by automatic steering of the steering handle based on the planned travel line, and a steering changeover switch 52 that is arranged around the steering shaft and can swing in a first direction to switch between starting and ending automatic steering, and in a second direction to set the start and end points of a travel reference line that serves as the basis for the planned travel line, with the base end provided on the steering shaft as a fulcrum.

[0140] This configuration offers excellent operability because it is possible to switch between starting and ending automatic steering and to set the start and end points of a driving reference line that serves as the reference for the planned driving line, simply by changing the swing direction of the steering changeover switch 52. Furthermore, compared to when multiple switches are provided as the steering changeover switch 52, it is possible to reduce the installation space for the steering changeover switch 52.

[0141] Furthermore, the first direction of swinging of the steering changeover switch 52 is swinging upward or downward, and the second direction of swinging of the steering changeover switch 52 is swinging forward or backward. With this configuration, by swinging the steering changeover switch 52 upward, downward, forward or backward, it is possible to switch between starting and ending automatic steering and to set the start and end points of the driving reference line that serves as the basis for the planned driving line, making it easy to operate.

[0142] In addition, the steering changeover switch 52 commands the start of automatic steering by swinging downward, commands the end of automatic steering by swinging upward, sets the start point of the driving reference line by swinging backward, and sets the end point of the driving reference line by swinging forward. According to this configuration, the operations of starting automatic steering, ending automatic steering, setting the start point of the driving reference line, and setting the end point of the driving reference line can be performed easily and reliably.

[0143] The system also includes a setting switch 51 that is arranged around the steering shaft 31 and switches to a setting mode in which at least settings are made before the start of automatic steering. According to this configuration, the setting switch 51, in addition to the steering changeover switch 52, is arranged around the steering shaft 31, so that it is possible to provide a variety of switches while reducing the space required for arranging the switches.

[0144] It also includes a position detection device 40 that detects the position of the vehicle body based on signals from positioning satellites, and a correction switch 53 that is arranged around the steering shaft 31 and corrects the position detected by the position detection device 40. According to this configuration, the steering changeover switch 52, setting switch 51, and correction switch 53 are arranged together around the steering shaft 31, so that a wide variety of switches can be provided while the space required for arranging the switches can be reduced.

[0145] The display device 45 also includes a screen changeover switch 54 that is arranged around the steering shaft 31 and selectively switches the display between a first screen Q1 that displays the driving situation in the setting mode and a second screen Q2 that explains the setting operations in the setting mode. According to this configuration, in addition to the steering changeover switch 52, setting switch 51, and correction switch 53, the screen changeover switch 54 is also arranged in a concentrated manner around the steering shaft 31. Therefore, it is possible to provide a wide variety of switches while reducing the space required for arranging the switches.

[0146] The work vehicle 1 also comprises a vehicle body 3 that can be driven either by manual steering using a steering wheel 30 or by automatic steering of the steering wheel based on the planned driving line, a receiving device 41 that is mounted on the vehicle body and receives signals from positioning satellites, an inertial measurement device 42 that measures the inertia of the vehicle body, an automatic steering mechanism 37 that automatically steers the steering wheel based on the signal received by the receiving device and the inertia measured by the inertial measurement device, a vibration-damping member 64 that suppresses vibration of the inertial measurement device, and a support member 65 that supports the inertial measurement device on the vehicle body via the vibration-damping member.

[0147] According to this configuration, the vibration-isolating member 64 prevents vibrations of the vehicle body 3 and the like from being transmitted to the inertial measurement unit 42. This reduces measurement errors of the inertial measurement unit 42, enabling accurate automatic steering. It also includes a drive unit (e.g., transmission 5) that drives the vehicle body and a housing (e.g., transmission case 74) that covers the drive unit, and the support member 65 supports the inertial measurement unit 42 on the housing via the vibration-damping member 64.

[0148] According to this configuration, the vibration isolation member 64 prevents vibrations caused by driving the drive unit from being transmitted to the inertial measurement unit 42. Therefore, the measurement error of the inertial measurement unit 42 can be reduced. It also includes a support plate 66 attached to the housing 74, and the support member 65 has an attachment portion 65a that is positioned below the support plate 66 and to which the inertial measurement unit 42 is attached, and a fixed portion 65b that rises from the attachment portion 65a and is fixed to the support plate 66 via a vibration-damping member 64.

[0149] With this configuration, the inertial measurement unit 42 can be attached in a state in which it is suspended below the support plate 66 attached to the housing 74, with the vibration-isolating member 64 interposed between the support plate 66 and the inertial measurement unit 42. Therefore, the vibration-isolating member 64 can effectively prevent vibrations from being transmitted to the inertial measurement unit 42. Furthermore, it is possible to ensure space above the support plate 66 for installing a driver's seat, etc.

[0150] The vehicle also includes a driver's seat 10 provided on the vehicle body 3, and a support plate 66 supports the driver's seat from below. According to this configuration, the inertial measurement unit 42 can be disposed below the driver's seat 10 via the support plate 66. Therefore, the inertial measurement unit 42 can be disposed near the center of gravity of the vehicle body 3, and the measurement accuracy of the inertial measurement unit 42 can be improved.

[0151] The fixed portion 65b is fixed to the support plate 66 by a bolt B3, and the vibration-isolating member 64 is interposed between the bolt and the fixed portion, and between the fixed portion and the support plate. According to this configuration, the vibration-isolating member 64 can reliably prevent vibrations of the support plate 66 from being transmitted to the inertial measurement unit 42 via the support member 65 . The housing is a transmission case 74, and the support plate 66 is attached to the top of the transmission case.

[0152] According to this configuration, by attaching support plate 66 to a highly rigid transmission case, vibration of support plate 66 to which support member 65 is fixed is suppressed, thereby improving the measurement accuracy of inertial measurement unit 42. The support plate 66 also has an opening 66c provided above the inertial measurement unit 42, and the inertial measurement unit is exposed through the opening.

[0153] With this configuration, opening 66c can be used to easily attach and detach inertial measurement unit 42. Furthermore, by having the upper part of inertial measurement unit 42 protrude from opening 66c, the space occupied by inertial measurement unit 42 in the thickness direction (vertical direction) can be reduced. Although one embodiment of the present invention has been described above, the embodiment 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]

[0154] 1. Work vehicle (tractor) 3. Body 30 Steering wheel 31 Steering shaft 37 Automatic steering mechanism 38 Steering motor 39 Gear mechanism 390 Connecting shaft 391 1st Gear (Gear) 392 Second Gear (Gear) 393 3rd Gear (Gear) 394 4th Gear (Gear) 45 Display device 52 Steering switch 60B Second control device (control device) 78 Panel Cover

Claims

1. A steering handle, a steering shaft that rotatably supports the steering handle; a vehicle body capable of traveling by either manual steering using the steering wheel or automatic steering of the steering wheel based on a planned traveling line; a steering motor that rotates the steering wheel during the automatic steering; A steering changeover switch that is disposed around the steering shaft and switches between starting and ending the automatic steering; An automatic steering mechanism that performs automatic steering of the vehicle body; A control device for controlling the steering motor; Equipped with the automatic steering mechanism has a gear mechanism including a gear provided on the steering shaft and rotating together with the steering shaft, and a gear provided on a rotation shaft of the steering motor and rotating together with the rotation shaft, the steering changeover switch, the control device and the gear mechanism are disposed below the steering handle, the steering motor, the gear mechanism, and the control device are arranged side by side along an axial direction of the steering shaft in a side view, The control device is disposed on the opposite side of the steering motor with respect to the axial direction of the steering shaft, with the gear mechanism interposed therebetween, in a side view of the tractor.

2. 2. The tractor according to claim 1, wherein the gear mechanism is disposed below the steering changeover switch.

3. 3. The tractor according to claim 1, wherein the gear mechanism is disposed across one side and the other side of the steering shaft.

4. The tractor according to any one of claims 1 to 3, wherein the gear mechanism includes a first gear attached to the output shaft of the steering motor, a second gear meshing with the first gear, and a fourth gear attached to the steering shaft and rotating together with the steering shaft as the second gear rotates.

5. the gear mechanism includes a third gear connected to the second gear by a connecting shaft, the second gear and the third gear rotate integrally with the connecting shaft, 5. The tractor of claim 4, wherein said fourth gear meshes with said third gear.

6. A display device capable of displaying tractor operation information; A panel cover for supporting the display device; Equipped with The tractor according to any one of claims 1 to 5, wherein the steering motor, the gear mechanism and the control device are disposed inside the panel cover.

7. The control device has a housing and a circuit board disposed within the housing, The tractor according to claim 6 , wherein the housing is a rectangular parallelepiped and is arranged vertically inside the panel cover with the shortest side facing in the vehicle body width direction or substantially in the vehicle body width direction.

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