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 Art

[0002] Conventionally, a work vehicle (tractor) disclosed in Patent Document 1 is known. The work vehicle disclosed in Patent Document 1 includes a GPS position calculation means for receiving radio waves transmitted from GPS satellites and calculating the position of the vehicle body, a steering drive means for rotating the steering device, an engine rotation control means, a transmission means, and a control unit for controlling these. It has an automatic driving mode in which the steering drive means, the engine rotation control means, and the transmission means are controlled to travel along a set route based on the position of the vehicle body to enable automatic driving, and a manual driving mode in which the vehicle body can travel in response to manual operations of a transmission operation means, a steering operation means, and an engine rotation operation means.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The above work vehicle includes an automatic / manual changeover switch as a mode changeover operation means for switching between an automatic driving mode and a manual driving mode. However, Patent Document 1 does not disclose the specific arrangement of the automatic / manual changeover switch, nor does it disclose a switch for switching to a setting mode for performing settings before the start of automatic steering. Therefore, it has been difficult to surely prevent misoperations of a plurality of switches related to automatic steering in the work vehicle disclosed in Patent Document 1.

[0005] The present invention has been made in view of the above prior art, and aims to provide a work vehicle (tractor) that can reliably prevent erroneous operation of multiple switches involved in automatic steering. [Means for solving the problem]

[0006] A tractor according to one aspect of the present invention comprises a steering wheel, a steering shaft that rotatably supports the steering wheel, a vehicle body capable of driving by either manual steering using the steering wheel or automatic steering of the steering wheel based on a planned driving line, and a steering switch arranged around the steering shaft for switching the start or end of the automatic steering, wherein the steering switch can be operated in at least two directions from a neutral position, such as up, down, forward, and backward, and the starting point of the driving reference line for the automatic steering is set when the steering switch is operated from the neutral position in a first predetermined direction of the two directions, and the automatic steering is started when the steering switch is operated from the neutral position in a second predetermined direction of the two directions.

[0007] The tractor is equipped with a shuttle lever for operating the vehicle's direction of travel, and the steering switch may be positioned in the same direction as the shuttle lever with respect to the steering shaft.

[0008] The grip portion of the steering selector switch may be positioned closer to the steering wheel than the grip portion of the shuttle lever.

[0009] The steering selector switch may have a first direction of oscillation that is either upward or downward, with a downward oscillation commanding the start of automatic steering and an upward oscillation commanding the end of automatic steering.

[0010] The steering selector switch is configured such that the oscillation in the second direction is either forward or backward, with backward oscillation setting the starting point of the driving reference line, and forward oscillation setting the driving reference line It may also be used to set the endpoint of the input. [Effects of the Invention]

[0011] According to the tractor described above, it is possible to reliably prevent accidental operation of the multiple switches involved in automatic steering. [Brief explanation of the drawing]

[0012] [Figure 1] This diagram shows the configuration and control block diagram of a work vehicle (tractor). [Figure 2] This is an explanatory diagram illustrating automatic steering. [Figure 3A] This is an explanatory diagram illustrating the correction amount in a push switch. [Figure 3B] This is an explanatory diagram illustrating the correction amount in a slide switch. [Figure 4A] This diagram shows the first and second correction units in a push switch. [Figure 4B] This diagram shows the first and second correction units in a slide switch. [Figure 5A] This shows the state when the vehicle's calculated position shifts to the right while the vehicle is moving straight with automatic steering enabled. [Figure 5B]It shows the state when the calculated vehicle body position deviates to the left during straight-ahead automatic steering. [Figure 6] It is an explanatory diagram for explaining automatic operation. [Figure 7] It is a plan view showing the main part of the internal structure of the front part of the vehicle body. [Figure 8] It is a left side view showing the main part of the internal structure of the front part of the vehicle body. [Figure 9] It is a right side view showing the main part of the internal structure of the front part of the vehicle body. [Figure 10] It is a rear view showing the main part of the internal structure of the front part of the vehicle body. [Figure 11] It is a rear view showing the steering handle, cover, etc. [Figure 12] It is a view seen from the vertical direction with respect to the display surface of the display device for showing the panel cover, etc. [Figure 13] It is a view seen from above in the axial direction of the steering shaft for showing the panel cover, etc. [Figure 14] It is a left side view for explaining the movement of the steering changeover switch. [Figure 15] It is a rear perspective view showing the main part of the internal structure of the front part of the vehicle body. [Figure 16] It is a plan view showing an enlarged part (front part) of FIG. 7. [Figure 17] It is a right rear perspective view showing the steering handle, gear mechanism, etc. [Figure 18] It is a view showing the gear mechanism as seen from the left. [Figure 19] It is a perspective view showing the mounting structure of the inertial measurement device. [Figure 20] It is a plan view showing the mounting structure of the inertial measurement device. [Figure 21] It is a perspective view showing the inertial measurement device, support member, vibration damping member, and support plate. [Figure 22] It is a right side view showing the mounting structure of the inertial measurement device. [Figure 23] It is a right side view showing an enlarged rear part of the mounting structure of the inertial measurement device. [Figure 24] It is a sectional view taken along line A-A of FIG. 20. [Figure 25] This is a cross-sectional view showing an enlarged portion (left side) of Figure 24. [Figure 26] This is a schematic plan view illustrating the mounting position of the inertial measurement device. [Figure 27] This figure shows an example of the first and second screens that can be switched using a screen switching switch. [Figure 28] This is a left side view of a work vehicle (tractor). [Figure 29] This is a plan view of a work vehicle (tractor). [Modes for carrying out the invention]

[0013] Hereinafter, embodiments of the present invention will be described based on the drawings. <Overview of work vehicles> Figure 28 is a side view showing one embodiment of the work vehicle 1, and Figure 29 is a top view showing one embodiment of the work vehicle 1. In this embodiment, the work vehicle 1 is a tractor. However, the work vehicle 1 is not limited to a tractor, and may be agricultural machinery (agricultural vehicle) such as a combine harvester or transplanter, or construction machinery (construction vehicle) such as a loader.

[0014] In the following explanation, the front of the driver seated in the driver's seat 10 of the tractor (work vehicle) 1 (direction of arrow A1 in Figure 28) will be referred to as the front, the rear of the driver (direction of arrow A2 in Figure 28) as the rear, the left side of the driver (direction of arrow B1 in Figure 29) as the left, and the right side of the driver (direction of arrow B2 in Figure 29) as the right. Furthermore, the horizontal direction (direction of arrow B3 in Figure 29), which is perpendicular to the front-to-back direction of the tractor 1, will be referred to as the vehicle width direction.

[0015] As shown in Figure 28, the tractor 1 comprises a body 3, a prime mover 4, and a transmission 5. The body 3 has a running gear 7 and is capable of movement. The running gear 7 is a device having front wheels 7F and rear wheels 7R. The front wheels 7F may be of the tire type or the crawler type. Similarly, the rear wheels 7R may also be of the tire type or the crawler type. The prime mover 4 is a diesel engine, an electric motor, etc., and in this embodiment it is a diesel engine. The transmission 5 can switch the propulsion force of the running gear 7 by changing the gear, and can also switch the running gear 7 between forward and reverse. The vehicle body 3 is provided with a driver's seat 10.

[0016] Furthermore, a coupling section 8, consisting of a three-point linkage mechanism, is provided at the rear of the vehicle body 3. Working devices can be attached to and detached from the coupling section 8. By connecting the working devices to the coupling section 8, the vehicle body 3 can tow the working devices. The working devices include tilling devices for cultivating, fertilizer spreaders for spreading fertilizer, pesticide sprayers for spraying pesticides, harvesting devices for harvesting, mowing devices for cutting pasture grass, etc., spreading devices for spreading pasture grass, etc., hay collecting devices for collecting pasture grass, etc., and shaping devices for shaping pasture grass, etc.

[0017] As shown in Figure 1, the transmission 5 comprises a main shaft (drive shaft) 5a, a main transmission unit 5b, a sub-transmission unit 5c, a shuttle unit 5d, a PTO power transmission unit 5e, and a front transmission unit 5f. The drive shaft 5a is rotatably supported in the housing case (transmission case) of the transmission 5, and power from the crankshaft of the engine 4 is transmitted to the drive shaft 5a. The main transmission unit 5b has multiple gears and a shifter that changes the connection of these gears. The main transmission unit 5b changes the rotation input from the drive shaft 5a and outputs it (changes speed) by appropriately changing the connection (meshing) of the multiple gears with the shifter.

[0018] The sub-transmission unit 5c, like the main transmission unit 5b, has multiple gears and a shifter that changes the connections between those gears. The sub-transmission unit 5c appropriately changes the connections (meshing) of the multiple gears using the shifter. This changes the rotation input from the main transmission unit 5b and outputs it (changes the speed). 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, and the rotation direction of the shuttle shaft 12, i.e., the forward and reverse movement of the tractor 1, is switched by engaging and disengaging the hydraulic clutch. The shuttle shaft 12 is connected to the rear wheel differential device 20R. The rear wheel differential device 20R rotatably supports the rear axle 21R to which the rear wheels 7R are attached.

[0019] The PTO power transmission unit 5e includes a PTO drive shaft 14 and a PTO clutch 15. The PTO drive shaft 14 is rotatably supported and capable of receiving power from the drive shaft 5a. The PTO drive shaft 14 is connected to the PTO shaft 16 via gears or the like. The PTO clutch 15 is, for example, a hydraulic clutch, and by engaging and disengaging the hydraulic clutch, it switches between a state in which power from the drive shaft 5a is transmitted to the PTO drive shaft 14 and a state in which power from the drive shaft 5a is not transmitted to the PTO drive 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 are capable of receiving power from the drive shaft 5a, for example, power from the shuttle shaft 12 is transmitted via gears and a transmission shaft. Power from the first clutch 17 and the second clutch 18 can be transmitted to the front axle 21F via the front transmission shaft 22. Specifically, the front transmission shaft 22 is connected to the front differential device 20F, and the front 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, etc. An oil passage is connected to the first clutch 17, and this oil passage is connected to a first operating valve 25 to which hydraulic fluid discharged from a hydraulic pump is supplied. The first clutch 17 switches between an engaged state and an engaged state depending on the opening degree of the first operating valve 25. An oil passage is connected to the second clutch 18, and this oil passage is connected to a second operating valve 26. The second clutch 18 switches between an engaged state and an engaged 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 they switch between an engaged state and an engaged state by energizing or demagnetizing the solenoid of the solenoid valve.

[0022] When the first clutch 17 is disengaged and the second clutch 18 is engaged, power from the shuttle shaft 12 is transmitted to the front wheel 7F via the second clutch 18. This results in four-wheel drive (4WD) with both the front and rear wheels driven by power, 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, it becomes four-wheel drive, and the rotational speed of the front wheels is faster than that of the rear wheels (4WD increased speed state). Furthermore, when both the first clutch 17 and the second clutch 18 are engaged, power from the shuttle shaft 12 is not transmitted to the front wheel 7F, resulting in two-wheel drive (2WD) with only the rear wheels driven by power. <Overview of the position detection device> 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 satellite positioning systems (positioning satellites) such as D-GPS, GPS, GLONASS, Beidou, Galileo, and Michibiki. That is, the position detection device 40 receives received signals (position of the positioning satellite, transmission time, correction information, etc.) transmitted from the positioning satellite and detects the position (e.g., latitude and longitude) based on the received signals. The position detection device 40 has a receiving device 41 and an inertial measurement unit (IMU) 42.

[0023] The receiving device 41 is a device that has an antenna and the like and receives received signals transmitted from positioning satellites, and is mounted on the vehicle body 3 separately from the inertial measuring device 42. In this embodiment, The receiving device 41 is mounted on the lops 61 provided on the vehicle body 3. Note that the mounting location of the receiving device 41 is not limited to this embodiment. The inertial measuring device 42 includes an acceleration sensor for detecting acceleration, a gyro sensor for detecting angular velocity, and the like. It is installed below the vehicle body 3, for example, the driver's seat 10, and the inertial measuring device 42 can detect the roll angle, pitch angle, yaw angle, etc., of the vehicle body 3. <Overview of steering systems, manual steering, and automatic steering> As shown in Figure 1, the tractor 1 is equipped with a steering device 11. The steering device 11 is capable of manual steering, in which the vehicle body 3 is steered by the driver, and automatic steering, in which the vehicle body 3 is steered automatically without driver intervention.

[0024] The steering system 11 includes a steering handle (steering wheel) 30 and a steering shaft (rotating axis) 31 that rotatably supports the steering handle 30. The steering system 11 also includes an auxiliary mechanism (power steering device) 32. The auxiliary mechanism 32 assists in the manual steering of the steering handle 30. More specifically, the auxiliary mechanism 32 assists in the rotation of the steering shaft 31 (steering handle 30) by hydraulics or the like. The auxiliary mechanism 32 includes a hydraulic pump 33, a control valve 34 to which hydraulic fluid discharged from the hydraulic pump 33 is supplied, and a steering cylinder 35 operated by the control valve 34. The control valve 34 is a three-position switching valve that can be switched by the movement of a spool, for example, and switches in accordance with the steering direction (rotation direction) of the steering shaft 31. The steering cylinder 35 is connected to an arm (knuckle arm) 36 that changes the direction of the front wheel 7F.

[0025] Therefore, when the driver grips the steering wheel 30 and operates it in one direction or the other, the switching position and opening degree of the control valve 34 are switched in accordance with the direction of rotation of the steering wheel 30, and the steering cylinder 35 extends or retracts to the left or right in accordance with the switching position and opening degree of the control valve 34, thereby changing the steering direction of the front wheels 7F. In other words, the vehicle body 3 can change its direction of travel to the left or right by manually steering the steering wheel 30.

[0026] Next, I will explain automatic steering. As shown in Figure 2, when performing automatic steering, first, a driving reference line L1 is set before performing automatic steering. After setting the driving reference line L1, automatic steering can be performed by setting a planned driving line L2 that is parallel to the driving reference line L1. In automatic steering, the tractor 1 (vehicle body 3) is automatically steered in the direction of travel so that the vehicle position measured by the position detection device 40 matches the planned driving line L2.

[0027] Specifically, before automatic steering is performed, the tractor 1 (vehicle body 3) is moved to a predetermined position in the field (S1), and when the driver operates the steering switch 52 provided on the tractor 1 at the predetermined position (S2), the vehicle position measured by the position detection device 40 is set to the starting point P10 of the driving reference line L1 (S3). Then, when the tractor 1 (vehicle body 3) is moved from the starting point P10 of the driving reference line L1 (S4), and when the driver operates the steering switch 52 at the predetermined position (S5), the vehicle position measured by the position detection device 40 is set to the ending point P11 of the driving reference line L1 (S6). Therefore, the straight line connecting the starting point P10 and the ending point P11 is set as the driving reference line L1.

[0028] After setting the reference driving line L1 (after S6), for example, if the tractor 1 (vehicle body 3) is moved to a location different from where the reference driving line L1 was set (S7), and the driver operates the steering switch 52 (S8), a planned driving line L2, which is a straight line parallel to the reference driving line L1, is set (S9). After setting the planned driving line L2, automatic steering is started, and the direction of travel of the tractor 1 (vehicle body 3) is changed to follow the planned driving line L2. For example, if the current vehicle position is to the left of the planned driving line L2, the front wheels 7F are steered to the right, and if the current vehicle position is to the right of the planned driving line L2, the front wheels 7F are steered to the left. During automatic steering, the driving speed (vehicle speed) of the tractor 1 (vehicle body 3) can be changed by the driver manually changing the amount of operation of the accelerator member (accelerator pedal, accelerator lever) provided on the tractor 1, or by changing the gear of the transmission.

[0029] Furthermore, after automatic steering has started, the driver can terminate automatic steering by operating the steering selector switch 52 at any point. In other words, the endpoint of the planned driving line L2 can be set by terminating automatic steering by operating the steering selector switch 52. This means that the length from the start to the end of the planned driving line L2 can be set to be longer or shorter than the driving reference line L1. In other words, the planned driving line L2 is not associated with the length of the driving reference line L1, and the vehicle can be driven while automatically steering for a longer distance than the length of the driving reference line L1 by following the planned driving line L2.

[0030] As shown in Figure 1, the steering system 11 has an automatic steering mechanism 37. The automatic steering mechanism 37 is a mechanism that automatically steers the vehicle body 3, and automatically steers the vehicle body 3 based on the position of the vehicle body 3 (vehicle body position) detected by the position detection device 40. More specifically, the automatic steering mechanism 37 automatically steers the steering wheel 30 based on the signal received by the receiving device 41 and the inertia measured by the inertia measuring 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 provided on the steering shaft 31 and rotating together with the steering shaft 31, and a gear provided on the rotation axis of the steering motor 38 and rotating together with the rotation axis. When the rotation axis of the steering motor 38 rotates, the steering shaft 31 automatically rotates via the gear mechanism 37, and the steering direction of the front wheels 7F can be changed so that the vehicle body position matches the planned driving line L2. <Overview of the display device> As shown in Figures 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 about the tractor 1, and is capable of displaying at least the driving information of the tractor 1. The display device 45 is located in front of the driver's seat 10. <Overview of setting switches and steering selector switches> As shown in Figure 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 the 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, for example, a mode in which the start and end points of the driving reference line L1 are set.

[0031] The setting switch 51 can be switched ON or OFF. When ON, it outputs a signal indicating that the setting mode is active, and when OFF, it outputs a signal indicating that the setting mode is inactive. Additionally, when the setting switch 51 is ON, it outputs a signal to the display device 45 indicating that the setting mode is active, and when OFF, it outputs a signal to the display device 45 indicating that the setting mode is inactive.

[0032] Tractor 1 is equipped with a steering selector switch 52. The steering selector switch 52 is a switch that switches the start or end of automatic steering in the setting mode. Specifically, the steering selector switch 52 can be switched up, down, forward, and backward from the neutral position. When the setting mode is active and the switch is set downward from the neutral position, it outputs the start of automatic steering, and when the setting mode is active and the switch is set upward from the neutral position, it outputs the end of automatic steering. Furthermore, when the steering selector switch 52 is set backward from the neutral position while the setting mode is active, it outputs that the current vehicle position is set to the starting point P10 of the driving reference line L1, and when the steering selector switch 52 is set forward from the neutral position while the setting mode is active, it outputs that the current vehicle position is set to the end point P11 of the driving reference line L1. <Overview of the correction switch> Tractor 1 is equipped with a correction switch 53. The correction switch 53 is a switch that corrects the vehicle position (latitude, longitude) measured by the position detection device 40. That is, the correction switch Switch 53 is a switch that corrects the vehicle position (referred to as the calculated vehicle position) calculated from the received signal (position of the positioning satellite, transmission time, correction information, etc.) and the measurement information (acceleration, angular velocity) measured by the inertial measuring device 42.

[0033] The compensation switch 53 consists of either a push switch that can be pressed or a slide switch that can be slid. The following describes the cases where the compensation switch 53 is a push switch and a slide switch, respectively. If the correction switch 53 is a push switch, the correction amount is set based on the number of times the push switch is operated. The correction amount is determined by correction amount = number of operations × correction amount per operation. For example, as shown in Figure 3A, the correction amount increases by several centimeters or 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, and the first control device 60A sets (calculates) the correction amount based on the number of operations.

[0034] Furthermore, if the correction switch 53 is a slide switch, the correction amount is set based on the amount of operation (displacement) of the slide switch. For example, the correction amount is determined by correction amount = displacement from a predetermined position. For example, as shown in Figure 3B, the correction amount increases by several centimeters or tens of centimeters for every 5 mm increase in the displacement of the slide switch. The amount of operation (displacement) of the slide switch is input to the first control device 60A, and the first control device 60A sets (calculates) the correction amount based on the displacement. Note that the method of increasing the correction amount and the rate of increase are not limited to the values ​​described above.

[0035] More specifically, as shown in Figures 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 the part that commands the correction of 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 the part that commands the correction of 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 Figure 4A, when the correction switch 53 is a push switch, the first correction unit 53A and the second correction unit 53B are ON or OFF switches that automatically return to their original position each time an operation is performed. The switches constituting the first correction unit 53A and the switches constituting the second correction unit 53B are integrated. However, the switches constituting the first correction unit 53A and the switches constituting the second correction unit 53B may be spaced apart from each other. As shown in Figure 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. Also, 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 Figure 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 elongated hole. 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 Figure 3B, when the knob 55 is gradually displaced to the left from a predetermined reference position, the left correction amount increases according to the amount of displacement. Also, when the knob 55 is gradually displaced to the right from a predetermined reference position, the right correction amount increases according to the amount of displacement. In addition, as shown in Figure 4B, when it is a slide switch, the first correction unit 53A and the second correction unit 53B may be formed as an integrated unit, the reference position of the knob 55 may be set to the center, the left correction amount may be set when it is moved to the left from the reference position, and the right correction amount may be set when the knob 55 is moved to the right from the intermediate position. Next, we will explain the relationship between the correction amount (left correction amount, right correction amount) from the correction switch 53, the planned route L2, and the behavior (travel trajectory) of the tractor 1 (vehicle body 3).

[0038] Figure 5A shows the state when the calculated vehicle position W1 shifts to the right while the vehicle is moving straight during automatic steering. As shown in Figure 5A, when automatic steering is started, if the actual position of the tractor 1 (vehicle body 3) (actual position W2) and the calculated vehicle position W1 match, and the actual position W2 matches the planned route L2, the tractor 1 will travel along the planned route L2. That is, in section P1 where there is no error in the positioning of the position detection device 40 and the vehicle position detected by the position detection device 40 (calculated vehicle position W1) is the same as the actual position W2, the tractor 1 will travel along the planned route L2. Note that if there is no error in the positioning of the position detection device 40 and no correction is performed, the calculated vehicle position W1 and the corrected vehicle position (corrected vehicle position) W3 corrected by the correction amount will be the same value. The corrected vehicle position W3 is given by Corrected Vehicle Position W3 = Calculated Vehicle Position W1 - Correction Amount.

[0039] Here, near position P20, even though the actual position W2 is not deviating from the planned route L2, various factors cause an error in the positioning of the position detection device 40, causing the vehicle position W1 detected by the position detection device 40 to shift to the right relative to the planned route L2 (actual position W2), and assuming that the amount of deviation W4 is maintained, the tractor 1 will determine that there is a deviation between the calculated vehicle position W1 and the planned route L2, and will steer the tractor 1 to the left to eliminate the amount of deviation W4 between the calculated vehicle position W1 and the planned route L2. As a result, the actual position W2 of the tractor 1 will shift to the planned route L2 due to the left steering. Subsequently, suppose the driver notices that the tractor 1 is deviating from the planned route L2, and at position P21 steers the second correction unit 53B to increase the right correction amount from zero. A rightward correction amount is applied to the calculated vehicle body position W1, and the corrected vehicle body position (corrected vehicle body position) W3 can be made approximately the same as the actual position W2. In other words, by setting the rightward correction amount by the second correction unit 53B, the vehicle body position of the position detection device 40 can be corrected in a direction that eliminates the amount of deviation W4 that occurred near position P20. Furthermore, as shown in position P21 in Figure 5A, if the actual position W2 of the tractor 1 is to the left of the planned route L2 after the vehicle body position correction, the tractor 1 is steered to the right, and the actual position W2 of the tractor 1 can be made to match the planned route L2.

[0040] Figure 5B shows the state when the calculated vehicle position W1 shifts to the left while the vehicle is moving straight during automatic steering. As shown in Figure 5B, when automatic steering is started, if the actual position W2 and the calculated vehicle position W1 coincide, and the actual position W2 coincides with the planned route L2, then, similar to Figure 5A, the tractor 1 will travel along the planned route L2. That is, similar to Figure 5A, in the section P2 where there is no error in the positioning of the position detection device 40, the tractor 1 will travel along the planned route L2. Also, similar to Figure 5A, the calculated vehicle position W1 and the corrected vehicle position W3 are the same value.

[0041] Here, at position P22, due to various influences, an error occurs in the positioning of the position detection device 40, causing the vehicle position W1 detected by the position detection device 40 to shift to the left relative to the actual position W2, and assuming that the amount of shift W5 is maintained, the tractor 1 will steer to the right to eliminate the amount of shift W5 between the calculated vehicle position W1 and the planned route L2. Subsequently, suppose the driver notices that the tractor 1 has deviated from the planned route L2, and the driver steers the first correction unit 53A at position P23 to increase the left correction amount from zero. In this case, the left correction amount is added to the calculated vehicle position W1, and the corrected vehicle position (corrected vehicle position) W3 can be made approximately the same as the actual position W2. In other words, by setting the left correction amount with the first correction unit 53A, the vehicle position of the position detection device 40 can be corrected in a direction that eliminates the amount of shift W5 that occurred near position P22. Furthermore, as shown at position P23 in Figure 5B, if, after correcting the vehicle position, the actual position W2 of tractor 1 is to the right of the planned route L2, tractor 1 will be steered to the left, bringing its actual position W2 to match the planned route L2. <Outline of the control device> As shown in Figure 1, the tractor 1 is equipped with multiple control devices 60. These multiple control devices 60 are devices that control the travel system, the work system, calculate the vehicle position, etc. of the tractor 1. The multiple control devices 60 are the first control device 60A, the second control device 60B, and the third control device 60C.

[0042] The first control device 60A receives the received signal (received information) received by the receiving device 41 and the measured information (acceleration, angular velocity, etc.) measured by the inertial measuring device 42, and determines the vehicle position based on the received information and the measured information. For example, if the correction amount by the correction switch 53 is zero, that is, if no correction of the vehicle position by the correction switch 53 is commanded, the first control device 60A does not perform any correction on the calculated vehicle position W1 calculated from the received information and the measured information, and determines the calculated vehicle position W1 to be the vehicle position used during automatic steering. On the other hand, if a correction of the vehicle position by the correction switch 53 is commanded, the first control device 60A sets the correction amount for the vehicle position based on either the number of times the correction switch 53 is operated or the amount of operation (displacement) of the correction switch 53, and determines the corrected vehicle position W3, obtained by correcting the calculated vehicle position W1 with the correction amount, to be the vehicle position used during automatic steering.

[0043] The first control device 60A sets a control signal based on the vehicle position (calculated vehicle position W1, corrected vehicle position W3) and the planned travel line L2, and outputs the control signal to the second control device 60B. Based on the control signal output from the first control device 60A, the second control device 60B controls the steering motor 38 of the automatic steering mechanism 37 so that the vehicle 3 travels along the planned travel line L2.

[0044] As shown in Figure 6, if the deviation between the vehicle position and the planned travel line L2 is less than a threshold, the second control device 60B maintains the rotation angle of the steering motor 38's rotation axis. If the deviation between the vehicle position and the planned travel line L2 is greater than or equal to the threshold, and the tractor 1 is positioned to the left of the planned travel line L2, the second control device 60B rotates the rotation axis of the steering motor 38 so that the steering direction of the tractor 1 is to the right. If the deviation between the vehicle position and the planned travel line L2 is greater than or equal to the threshold, and the tractor 1 is positioned to the right of the planned travel line L2, the second control device 60B rotates the rotation axis of the steering motor 38 so that the steering direction of the tractor 1 is to the left. In the above-described embodiment, the steering angle of the steering device 11 was changed based on the deviation between the vehicle body position and the planned travel line L2. However, if the direction of the planned travel line L2 and the direction of travel (vehicle body direction) F1 of the tractor 1 (vehicle body 3) are different, that is, if the angle θ of the vehicle body direction F1 with respect to the planned travel line L2 is greater than or equal to a threshold, the second control device 60B may set the steering angle so that the angle θ is zero (vehicle body direction F1 coincides with the direction 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 obtained based on the deviation (position deviation) and the steering angle obtained based on the direction (direction deviation θ). The setting of the steering angle in automatic steering in the above-described embodiment is just an example and is not limited to this.

[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. Furthermore, the control of the driving system, the control of the work system, and the calculation of the vehicle body position described above are not limited to these. <Specific configuration of the vehicle body, etc.> As shown in Figure 28, the vehicle body 3 includes 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 located at the front of the vehicle body 3 and rotatably supports the axle (front axle) 21F of the front wheel 7F. The front axle frame 70 also supports the motor 4 and extends forward from the motor 4. (The text then lists the components of the front axle frame 70, flywheel housing 71, and a cruising motion.) The latch housing 72, intermediate frame 73, and transmission case 74 are integrally connected to form a highly rigid vehicle frame.

[0047] The flywheel housing 71 is connected to the rear of the prime mover 4 and houses the 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 through 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 differential 20R.

[0048] As shown in Figure 7, the front axle frame 70 has a first frame 70A located on one side (left side) in the vehicle width direction, a second frame 70B located 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 Figures 7, 28, and 29, a weight 75 is attached to the front end of the front axle frame 70. A bonnet 76 is also attached to the upper part of the front axle frame 70.

[0049] The bonnet 76 covers the engine 4. More specifically, the bonnet 76 has an upper plate portion 76a that covers the top of the engine 4, a left plate portion 76b that covers the left side of the engine 4, a right plate portion 76c that covers the right side of the engine 4, and a front plate portion 76d that covers the front of the engine 4. A cover 77 that houses the steering shaft 31 and the like is provided at the rear of the bonnet 76. The steering wheel 30 is provided above the cover 77 and in front of the driver's seat 10. <Panel cover, column cover> As shown in Figures 8 to 10, the outer circumference 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 circumference of the steering post 80 is covered by a cover 77. The cover 77 is located 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 11-14, 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 bonnet 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 bonnet 76. The rear plate portion 78d of the panel cover 78 connects the rear end of the left plate portion 78b and 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 also connected to the upper plate portion 76a of the bonnet 76.

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

[0052] As shown in Figures 11 to 14, the upper plate portion 78a of the panel cover 78 has a mounting surface 78f on which the setting switch 51, the correction switch 53, and the screen switching switch 54 are attached. In other words, the panel cover 78 is equipped with the setting switch 51, the correction switch 53, and the screen switching switch 54. The mounting surface 78f is located behind the support portion 78e and below the steering handle 30. The support portion 78e and the mounting surface 78f are continuously and integrally constructed, with the support portion 78e located at the front of the upper plate portion 78a and the mounting surface 78f located at the rear of the upper plate portion 78a.

[0053] As shown in Figures 8, 9, 11, and 14, the mounting surface 78f is inclined to slope downwards as it moves towards the rear. As shown in Figure 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 the region located on one side (left) of the steering shaft 31. The second region 78f2 is the region located on the other side (right) of the steering shaft 31. The third region 78f3 is the region located behind the steering shaft 31. The setting switch 51, the correction switch 53, and the screen switching switch 54 are arranged around the steering shaft 31 by being mounted in one of the three regions (first region 78f1, second region 78f2, and third region 78f3) of the mounting surface 78f. The specific arrangement of the setting switch 51, the correction switch 53, and the screen switching switch 54 will be described later.

[0054] As shown in Figures 11-14, 28, and 29, the shuttle lever 81 protrudes from the left side (left plate portion 78b) of the panel cover 78. The shuttle lever 81 protrudes to the left from the left side of the panel cover 78 and then extends upward. The shuttle lever 81 is a component that switches the direction of travel of the vehicle body 3. More specifically, by operating (swinging) the shuttle lever 81 forward, the forward / reverse switching unit 13 outputs forward power to the running gear 7, and the direction of travel of the vehicle body 3 is switched to the forward direction. Also, by operating (swinging) the shuttle lever 81 backward, the forward / reverse switching unit 13 outputs reverse power to the running gear 7, and the direction of travel 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 running gear 7.

[0055] The tip (upper end) of the shuttle lever 81 is provided with a gripping portion 81a for the operator to grasp. As shown in Figure 11, the gripping portion 81a is positioned to the left of the grip 30a of the steering handle 30. Furthermore, the gripping portion 81a is positioned above the mounting surface 78f of the panel cover 78 and to the left of the mounting surface 78f. This prevents unintentional contact with various switches (such as the setting switch 51) on the mounting surface 78f when operating the shuttle lever 81, and prevents unintentional contact with the shuttle lever 81 when operating various switches on the mounting surface 78f.

[0056] As shown in Figures 11-14, 28, and 29, the column cover 79 is located below the steering wheel 30. As shown in Figures 8 and 9, the column cover 79 covers the upper part of the steering shaft 31 and the steering post 80. The column cover 79 is formed in a roughly rectangular tubular shape and protrudes upward from the mounting surface 78f of the panel cover 78. As shown in Figure 12, the first region 78f1, the second region 78f2, and the third region 78f3 of the mounting surface 78f are located 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 column cover 79. The setting switch 51, the correction switch 53, and the screen switching switch 54, which are mounted on the mounting surface 78f, are located around the column cover 79.

[0057] As shown in Figures 8, 9, and 11-14, the mounting surface 78f is at the lower end of the column cover 79. It is connected to the section and is located at the same height as the lower end. 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 switching switch 54 mounted on the mounting surface 78f are positioned away from the steering wheel 30.

[0058] The setting switch 51, calibration switch 53, and screen switching switch 54 are located away from the steering wheel 30, preventing unintentional contact with them while operating the steering wheel 30. Similarly, unintentional contact with the steering wheel 30 while operating the setting switch 51, calibration switch 53, and screen switching switch 54 is prevented. Therefore, unintended switching to automatic steering due to erroneous operation can be prevented. <Switch placement> Next, the arrangement of the setting switch 51, steering switch 52, correction switch 53, and screen switching switch 54 will be explained.

[0059] As shown in Figures 11 to 13, the setting switch 51, steering selector switch 52, correction switch 53, and screen selector switch 54 are arranged around the steering shaft 31. The specific arrangement of the setting switch 51, steering selector switch 52, correction switch 53, and screen selector switch 54 will be described below. As shown in Figures 11 to 13, the setting switch 51 is located on one side (left side) of the steering shaft 31 in the vehicle width direction. Furthermore, the setting switch 51 is located behind the steering shaft 31 in the front-rear direction. In other words, the setting switch 51 is located to the left and rear (diagonally left rear) of the steering shaft 31. In this embodiment, the setting switch 51 is composed of a push switch.

[0060] The setting switch 51 is positioned to the left and rear (diagonally to the left rear) of the column cover 79 in relation to the column cover 79. The setting switch 51 is positioned at the rear of the first region 78f1 of the mounting surface 78f of the panel cover 78 in relation to the mounting surface 78f. Furthermore, the setting switch 51 is positioned behind the display device 45 (towards the driver's seat 10) in relation to the display device 45. This allows the driver to easily and accurately operate the setting switch 51 while checking the display device 45 without changing their seated position in the driver's seat 10.

[0061] As shown in Figure 13, the setting switch 51 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 setting switch 51 is located inside the grip 30a of the steering handle 30 (closer to the axis of the steering shaft 31) when viewed from the axial direction of the steering shaft 31.

[0062] As shown in Figures 11 to 13, the steering selector switch 52 is located on one side (left side) of the steering shaft 31. In this embodiment, the steering selector switch 52 consists of a pivotable lever. The steering selector switch 52 is pivotable with a base end provided on the steering shaft 31 side as the pivot point. The base end of the steering selector switch 52 is located inside the column cover 79. The steering selector switch 52 protrudes from one side (left side) of the column cover 79.

[0063] The tip (left end) of the steering selector switch 52 is provided with a grip portion 52a for the operator to grasp. As shown in Figures 11 and 14, the grip portion 52a is located below and near the grip 30a of the steering handle 30. Furthermore, as shown in Figure 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 reach their fingers to the grip portion 52a and operate the steering selector switch 52 while holding the grip 30a of the steering handle 30.

[0064] Here, the grip portion 81a of the shuttle lever 81 is positioned below and to the left of the grip 30a of the steering handle 30, and is located in a position where the fingers cannot reach it when the grip 30a is being held. Therefore, it is possible to prevent the shuttle lever 81 from being operated unintentionally when operating the steering selector switch 52 while holding the grip 30a. Also, it is possible to prevent the steering selector switch 52 from being operated unintentionally when operating the shuttle lever 81.

[0065] As shown in Figure 14, the steering switch 52 is pivotable in a first direction (indicated by arrows C1 and C2) for switching the start or end of automatic operation, and in a second direction (indicated by arrows D1 and D2) for setting the start and end points of the reference line that serves as the basis for the planned driving line. The first direction of oscillation is an upward or downward oscillation from the neutral position. The second direction of oscillation is an forward or backward oscillation from the neutral position. When the setting mode is active, the steering selector switch 52 commands (outputs) the start of automatic steering by oscillating downward from the neutral position (in the direction of arrow C1) and commands (outputs) the end of automatic steering by oscillating upward from the neutral position (in the direction of arrow C2). Also, when the setting mode is active, the steering selector switch 52 sets the starting point of the driving reference line by oscillating backward from the neutral position (in the direction of arrow D1) and sets the ending point of the driving reference line by oscillating forward from the neutral position (in the direction of arrow D2).

[0066] As shown in Figures 11 to 13, the correction switch 53 is located to the other side (right) of the steering shaft 31 in the vehicle width direction. Furthermore, the correction switch 53 is located behind the steering shaft 31 in the front-rear direction. In other words, the correction switch 53 is located to the right and rear (diagonally to the right and rear) of the steering shaft 31. In this embodiment, the correction switch 53 is composed of a push switch. In relation to the column cover 79, the correction switch 53 is located to the right and rear (diagonally to the right and rear) of the column cover 79. In relation to the mounting surface 78f of the panel cover 78, the correction switch 53 is located at the rear of the second region 78f2 of the mounting surface 78f.

[0067] Furthermore, the correction switch 53 is positioned behind the display device 45 (towards the driver's seat 10) in relation to the display device 45. This allows the driver to easily and accurately operate the correction switch 53 while checking the display device 45 without changing their seated position in the driver's seat 10. As shown in Figure 13, the compensation 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 compensation switch 53 is located inside the grip 30a of the steering handle 30 (closer to the axis of the steering shaft 31) when viewed from the axial direction of the steering shaft 31.

[0068] The screen switching switch 54 changes the display on the display device 45 to the operating status in the setting mode (operation This is a switch that switches between the first screen Q1, which displays information, and the second screen Q2, which explains the setting operations in setting mode. Figure 27 shows an example of the first screen Q1 and the second screen Q2 displayed on the display device 45. As shown in Figures 12 and 13, the screen switching switch 54 is located to the other side (right) of the steering shaft 31 in the vehicle width direction. Furthermore, the screen switching switch 54 is located in front of the steering shaft 31 in the front-rear direction. In other words, the screen switching switch 54 is located to the right and in front (diagonally to the front right) of the steering shaft 31. In this embodiment, the screen switching switch 54 is composed of a push switch. In relation to the column cover 79, the screen switching switch 54 is located to the right and in front (diagonally to the front right) of the column cover 79. In relation to the mounting surface 78f of the panel cover 78, the screen switching switch 54 is located in front of the second region 78F of the mounting surface 78f. Also, the screen switching switch 54 is located in front of the correction switch 53.

[0069] As shown in Figure 13, the screen switching switch 54 does not overlap with the grip 30a of the steering wheel 30 when viewed from the axial direction of the steering shaft 31. Specifically, the screen switching switch 54 is located inside the grip 30a of the steering wheel 30 (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 selector switch 52, correction switch 53, and screen selector switch 54 are all located around the steering shaft 31. Therefore, the driver can easily see the location of each switch. In addition, the driver can operate each switch without changing their posture while remaining seated in the driver's seat 10. This improves operability and prevents accidental operation. Furthermore, the harnesses (wiring) routed from each switch can be shortened.

[0071] Furthermore, as shown in Figures 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 the turn signals, headlights, etc., located at the front of the vehicle body 3. The combination switch 82 is arranged around the steering shaft 31. Specifically, the combination switch 82 is located on one side (left side) of the steering shaft 31. In relation to the column cover 79, the combination switch 82 is located on one side (left side) of the column cover 79. In addition, the combination switch 82 is located below the steering selector switch 52 and in front of the setting switch 51.

[0072] As shown in Figure 13, the combination switch 82 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 combination switch 82 is located inside the grip 30a of the steering handle 30 (closer to the axis of the steering shaft 31) when viewed from the axial direction of the steering shaft 31.

[0073] Furthermore, regarding the arrangement of the various switches described above, the left and right positions may be reversed. That is, one side may be arranged as the left and the other as the right, or one side as the right and the other as the left. Specifically, for example, the setting switch 51 and the steering selector switch 52 may be placed to the right of the steering shaft 31, and the correction switch 53 may be placed to the left of the steering shaft 31. <Lifting lever (pump lever), accelerator lever> As shown in Figures 11 to 13, the tractor 1 is equipped with a lifting lever 83 and an accelerator lever 84.

[0074] The lifting lever 83 is a lever (pomper lever) that raises and lowers the connecting section 8. The lifting lever 83 is located on the other side (right side) of the steering shaft 31. The lifting lever 83 is pivotable using its base end, which is provided on the steering shaft 31 side, as a pivot point. The base end of the lifting lever 83 is located inside the panel cover 78. The lifting lever 83 protrudes upward from the other side (right side) of the panel cover 78, and its tip is located on the other side (right side) of the column cover 79.

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

[0076] As shown in Figures 12 and 13, the tip (right end) of the lifting lever 83 is provided with a gripping portion 83a for the operator to grasp. The gripping portion 83a is located below and near the grip 30a of the steering handle 30. As shown in Figure 13, the gripping portion 83a overlaps with the grip 30a when viewed from the axial direction of the steering shaft 31. This allows the operator to reach their fingers to the gripping portion 83a and operate the lifting lever 83 while holding the grip 30a of the steering handle 30.

[0077] The lifting lever 83 is positioned in the vehicle width direction on the opposite side of the steering switch 52 from the steering shaft 31. This prevents accidental operation caused by the operator's hand coming into contact with the lifting lever 83 when operating the steering switch 52, or vice versa. As shown in Figures 11 to 13, the accelerator lever 84 is located on the other side (right side) of the steering shaft 31. The accelerator lever 84 is pivotable around a base end provided on the steering shaft 31 side. The base end of the accelerator lever 84 is located 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 switching switch 54. The accelerator lever 84 protrudes upward from the mounting surface 78f and then extends to the right (away from the column cover 79).

[0078] The tip (right end) of the accelerator lever 84 is provided with a gripping portion 84a for the operator to grasp. The gripping portion 84a is located below the grip 30a of the steering handle 30. As shown in Figure 13, the gripping portion 84a overlaps with the grip 30a in the axial direction of the steering shaft 31. The gripping portion 84a of the accelerator lever 84 is located in front of and below the gripping portion 83a of the lifting lever 83. <Arrangement of automatic steering mechanism, etc.> Next, the arrangement of the automatic steering mechanism 37 will be explained.

[0079] As shown in Figures 10, 15-17, the steering motor 38 of the automatic steering mechanism 37 is positioned around the steering shaft 31. Specifically, the steering motor 38 is positioned below the steering wheel 30, in front of and to the right (diagonally to the front right) of the steering shaft 31. The output shaft (rotation axis) of the steering motor 38 is positioned 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 Figures 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 tubular shape and extends in the axial direction of the steering shaft 31. As shown in Figures 15 and 17, an upper plate 85a is provided at the upper end of the support post 85 to support the gear case 39a from below. Note that in Figure 17, the gear case 39a is omitted and the internal gears are shown. As shown in Figure 17, the lower part of the steering shaft 31, which 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 Figures 8 to 10 and 15, the lower end 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 integrated into a single unit. Specifically, the housing of the steering motor 38 is fixed to the upper part of the gear case 39a by bolts or the like. As shown in Figure 10, the steering motor 38 and gear mechanism 39 are positioned near the axis CL1 of the steering shaft 31. More specifically, in the vehicle width direction, the steering motor 38 and gear mechanism 39 are positioned closer to the axis CL1 of the steering shaft 31 than to the outer edge of the grip 30a of the steering handle 30. In other words, in the vehicle width direction, the steering motor 38 and gear mechanism 39 are positioned between a virtual line VL1, which is an extension downward of the outer end of one side of the grip 30a in the vehicle width direction, and a virtual line VL2, which is an extension downward of the outer end of the other side of the grip 30a in the vehicle width direction.

[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 mounted on the output shaft (rotation shaft) of the steering motor 38. The second gear 392 is located in front of the steering shaft 31 and meshes with the first gear 391. The third gear 393 is located 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 within 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 with the steering shaft 31.

[0083] When the steering motor 38 is driven and the output shaft rotates, the power of this 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 this 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 system placement, etc.> Next, the arrangement of the power steering system 32 will be described.

[0084] As shown in Figures 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 the first arm 90 via the first universal joint 87. The other end of the first arm 90 is connected to one end of the second arm 91 via the second universal joint 88. The other end of the second arm 91 is connected to one end of the third arm 92 via the third universal joint 89. The other end of the third arm 92 is connected to the power steering unit 93, which includes the control valve 34. Note that the configuration of the power steering device 32 shown in Figure 7 differs in part from the configuration shown in Figure 1, but either configuration may be adopted, or any other configuration may be adopted.

[0085] The power steering unit 93 shown in Figure 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 a 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 the pitman arm 94. The other end (outer end) of the tie rods 95 is connected to the left and right front wheels 7F. When the steering wheel 30 is manually rotated (steering), this rotation is transmitted from the steering shaft 31 to the power steering unit 93 via the linkage mechanism (universal joints 87, 88, 89 and arms 90, 91, 92), and the control valve 34 is activated (the spool moves). As a result, the hydraulic fluid discharged from the hydraulic pump 33 is sent to the steering cylinder 35, and the steering cylinder 35 is driven. The driving force of the steering cylinder 35 is transmitted to the tie rods 95 via the pitman arm 94, and the direction of the left and right front wheels 7F is changed as the tie rods 95 move.

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

[0088] If the automatic steering mechanism 37 and the power steering device 32 (for example, the control valve 34) are placed in close proximity, a large, combined space is required for their placement. However, by placing the automatic steering mechanism 37 and the power steering device 32 at separate locations, the space required for each is smaller, and a large, combined space is not necessary. <Arrangement of the first control device, second control device, etc.> As shown in Figures 8 and 9, the first control device 60A and the second control device 60B are located inside the panel cover 78. As shown in Figures 10 and 16, the first control device 60A is located on one side (left side) of the steering shaft 31. The second control device 60B is located 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] As described above, the first control device 60A and the second control device 60B are configured as separate units and are arranged on one side (left) and the other side (right) of the steering shaft 31. This allows the first control device 60A and the second control device 60B to be smaller than if they were a single integrated control device and to be positioned near the steering shaft 31. Therefore, the first control device 60A and the second control device 60B can be securely housed within the panel cover 78. Furthermore, because the first control device 60A and the second control device 60B are positioned separately, heat generated by one control device does not adversely affect the other.

[0090] The first control device 60A and the second control device 60B each have a housing and a circuit board located inside the housing. The circuit board is composed of various electrical and electronic components such as semiconductors and can perform the control described above. The housing is rectangular in shape and is arranged vertically. Specifically, the housing of the first control device 60A has its shortest side (length, width, and height) facing the vehicle width direction, and its longest side facing the up and down direction. The housing of the second control device 60B has its shortest side (of its three sides) facing approximately the vehicle width direction, and its longest side facing approximately the front and rear direction. In this way, the shortest side of the first control device 60A and the second control device 60B faces either the vehicle width direction or approximately the vehicle width direction. As a result, the area occupied by the first control device 60A and the second control device 60B in the vehicle width direction is reduced, so that the first control device 60A and the second control device 60B can be securely housed within the panel cover 78. Furthermore, because the panel cover 78 can be made smaller, sufficient legroom and forward visibility can be secured for the driver seated in the driver's seat 10. In addition, because the first control device 60A and the second control device 60B can be placed close together, the harness connecting the first control device 60A and the second control device 60B can be shortened, making it less susceptible to noise interference.

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

[0092] The second control unit 60B is positioned below the first control unit 60A. Furthermore, the second control unit 60B is positioned below the steering motor 38. In other words, the second control unit 60B is positioned lower than the first control unit 60A and the steering motor 38. This prevents the second control unit 60B from being adversely affected by heat generated by the first control unit 60A and the steering motor 38.

[0093] As shown in Figure 10, the second control device 60B and the steering motor 38 are positioned to the right of the axis CL1 of the steering shaft 31. Because the second control device 60B and the steering motor 38 are positioned in the same direction (to the right) in the vehicle width direction, the second control device 60B is located in close proximity to the steering motor 38. This allows for a shorter harness to electrically connect the second control device 60B and the steering motor 38, making it less susceptible to noise interference.

[0094] As shown in Figures 7, 10, and 15-17, 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 located on one side (left) of the steering shaft 31. The first control device 60A is fixed and held in the first holding portion 96a by fasteners such as bolts. The second holding portion 96b is located on the other side (right) of the steering shaft 31. The second control device 60B is fixed and held in 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] Specifically, as shown in Figure 16, the retaining member 96 (first retaining part 96a) supports the first control device 60A on one side (left side) of the steering shaft 31 and gear case 39a in a plan view. The retaining member 96 (second retaining part 96b) supports the second control device 60B on one side (left side) of the steering shaft 31 and gear case 39a in a plan view. Furthermore, the retaining member 96 (second retaining part 96b) supports the second control device 60B such that it shifts to one side (left side) as it moves from the front end to the rear end. This makes it possible to widen the space 200A between the connector side (front side) of the gear case 39a and the second control device 60B, making wiring and other work easier.

[0096] Furthermore, as shown in Figure 10, when viewing the first control device 60A and the second control device 60B with respect to the gear case 39a, the holding 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. The intermediate portion of the connecting portion 96c of the retaining member 96 in the vehicle body width direction is fixed to the connecting member 97 by welding or the like. The connecting member 97 extends in the front-rear direction. As shown in Figure 15, the connecting member 97 extends forward and backward from the connecting portion 96c, respectively. The rear end of the connecting member 97 is fixed to the upper part of the support post 85. The front end of the connecting member 97 is connected to the rear end of the stay 98 which extends in the front-rear direction.

[0097] More specifically, as shown in Figures 16 and 17, the connecting member 97 is made of a plate member and has a front plate portion 97a to which a connecting portion 96c is attached and which extends forward from the connecting portion 96c, a rear plate portion 97b to which the connecting portion 96c is attached and which extends rearward (towards the steering shaft 31) from the connecting portion 96c, a one-sided plate portion 97c extending from the rear plate portion 97b toward the first control device 60A, and a other-sided plate portion 97d extending from the rear plate portion 97B toward the second control device 60B. The one-sided plate portion 97c and the other-sided plate portion 97d are integrally formed and are inclined downward toward the steering shaft 31. The rear ends of the one-sided plate portion 97c and the other-sided 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 the partition plate 99. As shown in Figures 8 and 9, the partition plate 99 is located inside the bonnet 76, dividing 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 located in the first space S1. The fuel tank (not shown) is located in the second space S2. The lower part of the partition plate 99 is fixed to the upper part of the clutch housing 72. <Placement of receiving equipment, etc.> Next, the arrangement of the receiving device 41, which 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 3 based on the received signals. In other words, the receiving device 41 is a device that detects the position information of the vehicle 3 using a satellite positioning system (GNSS: Global Navigation Satellite System). For example, GPS (Global Positioning System) is used as the satellite positioning system. 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 3 based on the received signals. Specifically, the base station transmits correction information, including the base station's position information (reference position) and information obtained from signals from positioning satellites (distance between satellite receivers, etc.), to the receiving device 41 via wireless communication or the like. The receiving device 41 corrects the information received from positioning satellites based on the correction information obtained from the base station to obtain position information with higher accuracy. However, other methods such as the RTK method may be used as the method for detecting the vehicle position by the receiving device 41.

[0100] As shown in Figures 28 and 29, the receiving device 41 is attached to the LOPS 61. Before describing the mounting position of the receiving device 41, let's explain the specific configuration of the LOPS 61. The lops 61 are located behind the driver's seat 10. The lops 61 have a first vertical column 61a, a second vertical column 61b, and a horizontal column 61c. The first vertical column 61a, the second vertical column 61b, and the horizontal column 61c are integrally formed by bending a square pipe. The first vertical column 61a extends vertically to the left and rear of the driver's seat 10. The second vertical column 61b extends vertically to the right and rear of the driver's seat 10. The horizontal column 61c extends in the width direction of the vehicle body and is located above and behind the driver's seat 10, above the first vertical column 61a. The end is connected to the upper end of the second vertical column 61b. As a result, the rops 61 as a whole is formed in a roughly gate shape when viewed from the front. The rops 61 can swing backward using the pivot shafts 102 provided at the lower ends of the first vertical column 61a and the second vertical column 61b as fulcrums.

[0101] The receiving device 41 is attached to the horizontal section 61c of the LOPS 61. The receiving device 41 is The receiver 41 is fixed to a bracket 103, which is attached to the horizontal section 61c. The bracket 103 is attached to the center of the horizontal section 61c in the vehicle width direction and extends rearward from this center. As a result, the receiver 41 is located behind the center of the horizontal section 61c in the vehicle width direction. Thus, the receiver 41 is positioned offset (shifted) rearward from the locus 61. Furthermore, the receiver 41 is 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 attached to the first vertical column 61a or the second vertical column 61b of the rops 61, or to a location other than the rops 61 on the tractor 1. Alternatively, a canopy may be used instead of the rops 61, and the receiving device 41 may be attached to the canopy. <Placement of inertial measuring devices, etc.> Next, we will explain the arrangement of the inertial measuring devices 42 that constitute the position detection device 40.

[0103] The inertial measurement device 42 is a device for measuring the inertia of the vehicle body 3. More specifically, the inertial measurement device 42 can measure the inertia (inertial information) of the vehicle body 3, such as the yaw angle, pitch angle, and roll angle. As shown in Figures 19, 20, 28, and 29, the inertial measuring device 42 is located below the driver's seat 10 and on the centerline CL2 in the width direction of the vehicle body. In addition, the inertial measuring device 42 is positioned to overlap with the rear wheel 7R in a side view.

[0104] Furthermore, the inertial measuring device 42 is positioned above the transmission case 74. In other words, the inertial measuring device 42 is positioned to overlap with the transmission case 74 in a plan view. Because the inertial measuring device 39 is positioned to overlap with the transmission case 10, the position of the inertial measuring device 39 is close to the center of gravity of the vehicle body 3. Therefore, the inertial measuring device 39 can easily measure representative values ​​of the attitude change of the vehicle body 3 (values ​​that can represent the attitude change in the vehicle body 3), and the position of the vehicle body 3 can be determined quickly and accurately in response to the attitude change of the vehicle body 3. In other words, because the inertial measuring device 39 is positioned in a position on the vehicle body 3 where the weight balance in the front-rear, left-right, and height directions is good, the accuracy of measuring the position of the vehicle body 3 can be improved.

[0105] Furthermore, as shown in Figure 20, the inertial measuring device 42 is positioned on the axis CL3 of the rear axle in a plan view. When the work implement is attached to the coupling section 8, the center of gravity of the vehicle body 2 and the work implement is closer to the axis CL3 of the rear axle than to the longitudinal center of the vehicle body 2. Therefore, because the inertial measuring device 42 is positioned on the axis CL3 of the rear axle, even when the work implement is attached to the coupling section 8, the inertial measuring device 39 is close to the center of gravity of the vehicle body 3, allowing the position of the vehicle body 3 to be determined quickly and accurately.

[0106] The support structure (mounting structure) of the inertial measuring device 42 will be described below, primarily based on Figures 19 to 25. The inertial measuring device 42 is supported by a support member 65 via a vibration-damping member 64 to the vehicle body 3 (transmission case 74). The vibration-damping member 64 is a member that suppresses vibrations of the inertial measuring device 42, and is an elastically deformable member such as rubber or a spring.

[0107] The support member 65 supports the inertial measuring device 42 to the vehicle body 3 via the vibration-damping member 64. More specifically, the support member 65 supports the inertial measuring device 42 to a housing that covers the drive unit that drives the vehicle body 3 via the vibration-damping member 64. The drive unit is the prime mover 4 or a device that transmits power from the prime mover 4. In this embodiment, the drive unit is a transmission 5 and the housing is a transmission case 74. However, the housing to 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. Hereinafter, the explanation will be based on the assumption that the drive unit is a transmission 5 and the housing is a transmission case 74.

[0108] The support member 65 is attached to the support plate 66. The support plate 66 is attached to the 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 going through the support plate 66). The support plate 66 is positioned below the driver's seat 10 and supports the driver's seat 10 from below. A support bracket 100 and a cushioning material 101 are attached to the upper surface of the support plate 66. The support bracket 100 is fixed to the left front and right front of the support plate 66 by welding or the like, and extends 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 cushioning material 101 is made of an elastic material such as rubber. In this embodiment, the cushioning material 101 is cylindrical. The cushioning material 101 is fixed to the left rear and right rear of the support plate 66 by bolts or the like, respectively. The driver's seat 10 is supported above the support plate 66 by being placed on top of the support bracket 100 and the cushioning material 101.

[0109] The support plate 66 is attached to the upper part of the transmission case 74. As shown in Figures 19 and 22, the transmission case 74 has a projection 74a that protrudes upward from the upper surface of the transmission case 74. The projection 74a includes a front projection 74a1 that protrudes upward from the front of the transmission case 74 and a rear projection 74a2 that protrudes upward from the rear of the transmission case 74. The front projection 74a1 and the rear projection 74a2 are spaced apart in the front-rear direction and each extends in the vehicle width direction. Screw holes 74b extending in the vertical direction are formed in the front projection 74a1 and the rear projection 74a2, respectively. Multiple screw holes 74b are formed in each of the front projection 74a1 and the rear projection 74a2, spaced apart in the vehicle width direction. In this embodiment, two screw holes 74b are formed in the front projection 74a1 and two in the rear projection 74a2 (a total of four).

[0110] The support plate 66 has a first through hole 66a and a second through hole 66b. The first through-hole 66a is a hole for attaching the support plate 66 to the transmission case 74. As shown in Figures 19, 21, and 22, the first through-hole 66a is formed in positions corresponding to a plurality of screw holes 74b formed in the transmission case 74. Specifically, the first through-hole 66a includes a front through-hole 66a1 and a rear through-hole 66a2. The front through-hole 66a1 is formed in the left front and right front parts of the support plate 66, respectively. The rear through-hole 66a2 is formed in the left rear and right rear parts of the support plate 66, respectively. A bolt B1 is inserted through the first through-hole 66a, and the support plate 66 is fixed to the upper part of the transmission case 74 by screwing the bolt B1 into the screw holes 74b.

[0111] As described above, the transmission case 74 is integrally connected to the front axle frame 70, flywheel housing 71, clutch housing 72, and intermediate frame 73, thereby forming a highly rigid vehicle frame. Therefore, the support plate 66 is fixed to the highly rigid vehicle frame by being fixed to the transmission case 74. The second through-hole 66b is a hole for attaching the support member 65 to the support plate 66. As shown in Figures 21 and 24, the second through-hole 66b is located towards the rear of the support plate 66. More specifically, the second through-hole 66b is located behind the front through-hole 66a1 and in front of the rear through-hole 66a2. The second through-hole 66b includes a first through-hole 66b1 located on one side (left) in the vehicle width direction and a second through-hole 66b2 located on the other side (right) in the vehicle width direction. The first through-hole 66b1 and the second through-hole 66b2 are located symmetrically across the center line CL2 in the vehicle 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 located above one through hole 66b1. The second female threaded member 692 is located above the other through hole 66b2. The threaded hole of the first female threaded member 691 communicates with the 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 directly forming threaded holes in the support plate 66.

[0113] As shown in Figures 21 and 24, the support member 65 has a mounting portion 65a and a fixing portion 65b. The mounting portion 65a and the fixing portion 65b are integrally formed by bending a single plate (metal plate, etc.). The mounting portion 65a is located below the support plate 66. The mounting portion 65a is flat and is positioned parallel to the support plate 66. An inertial measuring device 42 is attached to the mounting portion 65a. Specifically, the inertial measuring device 42 is placed on the upper surface of the mounting portion 65a and fixed to the upper surface by a mounting fixture (bolt B2 and nut N1).

[0114] The fixing portion 65b rises from the mounting portion 65b. Specifically, the fixing portion 65b includes a first fixing portion 65b1 provided on the left side of the support member 65 and a second fixing portion 65b2 provided on the right side of the support member 65. The first fixing 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 to the left from the upper end of the first upright portion 62. The second fixing 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 to the right 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 positioned at the same height and parallel to the upper surface of the mounting portion 65a.

[0115] As shown in Figures 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 vertical direction. The first mounting hole 67a is positioned to overlap with one through hole 66b1. The second mounting hole 68a is positioned to overlap with the other through hole 66b2. Bolts B3 are inserted through the first mounting hole 67a and the second mounting hole 68a, respectively. The bolt B3 inserted through the first mounting hole 67a passes through one through hole 66b1 and is screwed into the threaded hole of the first female threaded member 691. The bolt B3 inserted through 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 bolts B3.

[0116] As shown in Figures 24 and 25, the fixed parts 65b (first fixed part 65b1, second fixed part 65b2) are fixed to the support plate 66 via vibration-damping members 64. The vibration-damping members 64 are made of a substantially cylindrical elastic body (such as rubber). As shown in Figure 25, the vibration-damping members 64 have a first large-diameter part 64a, a second large-diameter part 64b, and a small-diameter part 64c. The first large-diameter part 64a is provided on the upper part of the vibration-damping member 64. The second large-diameter part 64b is provided on the lower part of the vibration-damping member 64. The small-diameter part 64c is provided between the first large-diameter part 64a and the second large-diameter part 64b. Although Figure 25 shows the mounting structure of the vibration-damping member 64 in the first fixed part 65b1, the mounting structure of the vibration-damping member 64 in the second fixed part 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 circumferential surface of the bolt B3 and the inner circumferential surface of the mounting holes (first mounting hole 67a, second mounting hole 68a) of the support member 65. In this way, vibration-damping 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 the elastic deformation of the vibration-damping member 64 caused by the tightening of the bolt B3, or they may be formed when the vibration-damping member 64 is not elastically deformed. As described above, the support member 65 supports the inertial measuring device 42 below the support plate 66 via the vibration-damping member 64.

[0119] As shown in Figures 20 and 21, the support plate 66 has an opening 66c provided above the inertial measuring device 42. The inertial measuring device 42 is exposed through the opening 66c. In other words, the inertial measuring device 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 uppermost surface of the inertial measuring device 42 is located above the support plate 66, but is at least a distance from the underside of the driver's seat 10 that ensures contact with the underside is avoided. The opening 66c also exposes a mounting fixture (nut N1). This allows the mounting fixture to be easily removed by inserting a hand or tool through the opening 66c. Furthermore, by allowing the upper part of the inertial measuring device 42 to protrude from the opening 66c, the space occupied by the inertial measuring device 42 in the thickness direction (vertical direction) can be reduced.

[0120] Furthermore, the mounting position of the inertial measuring device 42 is not limited to the above embodiment. From the viewpoint of accurately detecting the behavior of the tractor (work vehicle) 1 using the inertial measuring device 42, there are mainly four possible mounting positions for the inertial measuring device 42. The first position is within the region connecting the left front wheel 7FL and the right front wheel 7FR, and the left rear wheel 7RL and the right rear wheel 7RR, and is indicated by the symbol A in Figure 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 Figure 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)), and is indicated by the symbol C in Figure 26. The range in which the ZMP moves, indicated by the symbol C in Figure 26, is the stable region in which the posture of the tractor 1 is stable when it is running (for example, the region in which it runs stably).

[0121] The ZMP can be calculated by providing multiple vehicle body state detection units on the vehicle body 3. Each vehicle body state detection unit is a device that detects at least the first load (ground reaction force) and moment acting on the vehicle body 3. For example, a 6-component load cell capable of detecting the first load and moment in three axial directions (X-axis direction, Y-axis direction, and Z-axis direction) is used. The X-axis direction can be set to the direction of travel of the vehicle body 3, the Y-axis direction to the width direction of the vehicle body, and the Z-axis direction to the vertical direction.

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

[0123] In Figure 26, the region Q1 connecting the support points of the vehicle body 3 (positions where multiple vehicle body state detection units are installed) is the critical region and is represented in two dimensions along the X and Y axes. The stable region Q2(C) is the stable region where the posture of the tractor 1 is stable when it is running, and is a region shifted inward by a predetermined distance from the critical region Q1. The region excluding the critical region Q1 and the stable region Q2, that is, the region between the contour lines constituting the critical region Q1 and the contour lines constituting the stable region Q2, is the unstable region Q3, which is prone to instability.

[0124] By positioning the inertial measuring device 42 within the stable region Q2(C), the measurement accuracy of the inertial measuring device 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 wheel 30, a steering shaft 31 that rotatably supports the steering wheel, a vehicle body 3 that can be driven by either manual steering using the steering wheel or automatic steering of the steering wheel based on the planned driving line, a setting switch 51 positioned around the steering shaft and switching to a setting mode that performs at least the settings before starting automatic steering, and a steering switch 52 positioned around the steering shaft and switching the start or end of automatic steering in the setting mode.

[0125] With this configuration, the setting switch 51 and the steering selector switch 52 are arranged around the steering shaft 31, allowing the driver to easily and reliably recognize the setting switch 51 and the steering selector switch 52 at a glance and operate them without changing their posture. Therefore, unintended automatic steering due to incorrect operation of the switches can be prevented.

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

[0127] Furthermore, the work vehicle 1 is equipped with a display device 45 positioned around the steering shaft 31 and displaying driving information, and a screen switching switch 54 positioned around the steering shaft and selectively switching the display of the display device between a first screen G1 that displays the driving status in setting mode and a second screen Q2 that explains the setting operation in setting mode. With this configuration, in addition to the setting switch 51, steering selector switch 52, and correction switch 53, the screen selector switch 54 is also arranged around the steering shaft 31. As a result, the driver can easily and reliably recognize the setting switch 51, steering selector switch 52, correction switch 53, and screen selector switch 54 at a glance and operate them without changing their posture. Therefore, unintended automatic steering due to incorrect operation of the switches can be prevented.

[0128] Furthermore, the setting switch 51 is located on one side of the steering shaft 31, and the correction switch 53 is located on the other side of the steering shaft 53. With this configuration, the setting switch 51 and the correction switch 53 are positioned opposite each other with the steering shaft 31 in between, which allows for effective use of the space around the steering shaft 31 and prevents accidental operation of the setting switch 51 and the correction switch 53.

[0129] Furthermore, the steering selector switch 52 is located on one side of the steering shaft 31. With this configuration, the steering selector switch 52 and the setting switch 51 are located on the same side with respect to the steering shaft 31, resulting in improved operability for operating the switches for automatic steering of the work vehicle 1.

[0130] Furthermore, the setting switch 51 is located on one side of the steering shaft 31, and the screen switching switch 54 is located on the other side of the steering shaft 31. With this configuration, the setting switch 51 and the screen switching switch 54 are positioned opposite each other with the steering shaft 31 in between, which allows for effective use of the space around the steering shaft 31 and prevents accidental operation of the setting switch 51 and the screen switching switch 54.

[0131] Furthermore, a panel cover 78 supporting the display device 45 is provided below the steering wheel 30, and the setting switch 51, calibration switch 53, and screen switching switch 54 are located on the panel cover. In this configuration, the setting switch 51, the correction switch 53, and the screen switching switch 54 are all located together on the panel cover 78 that supports the display device 45. As a result, the driver can see the setting switch 51, the correction switch 53, and the screen switching switch 54 together with the display device 45, resulting in improved operability. Furthermore, since the setting switch 51, the correction switch 53, and the screen switching switch 54 are positioned away from the steering wheel 30, it is prevented from unintentionally touching the setting switch 51, the correction switch 53, or the screen switching switch 54 when operating the steering wheel 30, and from unintentionally touching the steering wheel 30 when operating the setting switch 51, the correction switch 53, or the screen switching switch 54. Therefore, it is possible to prevent unintended switching to automatic steering due to erroneous operation.

[0132] Furthermore, the work vehicle 1 includes a connecting section 8 located at the rear of the vehicle body 3 and connected to a work device, and a lifting lever 83 for raising and lowering the connecting section 8. The lifting lever is located on the other side of the steering shaft 31. With this configuration, the lifting lever 83 and the steering selector switch 52 are positioned opposite each other with the steering shaft 31 in between, allowing for effective use of the space around the steering shaft 31. Furthermore, unintended operations by the driver are prevented by contact with the steering selector switch 52 when operating the lifting lever 83, or vice versa.

[0133] Furthermore, the setting switch 51 and the correction switch 53 are located behind the steering shaft 31. With this configuration, the setting switch 51 and the correction switch 53 are located on the driver's side when operating the steering wheel 30, resulting in improved operability of the setting switch 51 and the correction switch 53, and reducing the likelihood of accidental operation.

[0134] Furthermore, the work vehicle 1 includes a steering wheel 30, a steering shaft 31 that rotatably supports the steering wheel 30, a vehicle body 3 that can be driven by either manual steering using the steering wheel or automatic steering of the steering wheel based on a planned driving line, a position detection device 40 provided on the vehicle body that 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 positioned on one side of the steering shaft and outputting a control signal calculated based on the position of the vehicle body detected by the position detection device, and a second control device 60B positioned on the other side of the steering shaft and controlling the automatic steering mechanism so that the vehicle body drives along the planned driving line based on the control signal output by the first control device.

[0135] This configuration allows for a smaller control unit compared to a single integrated control unit comprising the first control unit 60A and the second control unit 60B. As a result, the control units (first control unit 60A and second control unit 60B) can be positioned in a small space near the steering shaft 31. Furthermore, since the first control unit 60A and the second control unit 60B are positioned in opposite directions with the steering shaft 31 in between, heat generated by one control unit prevents the other from being adversely affected.

[0136] Furthermore, the work vehicle 1 includes a display device 45 arranged around the steering shaft 31 and displaying driving information, and a panel cover 78 below the steering wheel 30 that supports the display device, with the first control device 60A and the second control device 60B located inside the panel cover 78. With this configuration, the first control device 60A and the second control device 60B are positioned near the steering shaft 41 and placed inside the panel cover 78, which allows the panel cover 78 to be made smaller. As a result, sufficient legroom and forward visibility for the driver can be ensured.

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

[0138] With this configuration, since the power steering device 32 and the automatic steering mechanism 37 are located at separate positions, the operation of the power steering device 32 and the operation of the automatic steering mechanism 37 can be made 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. Furthermore, the work vehicle 1 includes a display device 45 arranged around the steering shaft 31 and displaying driving information, a panel cover 78 below the steering wheel that supports the display device, and front wheels 7F and rear wheels 7R that support the vehicle body 3 so that it can move. The vehicle body has a front axle frame 72 that supports the front wheels, the automatic steering mechanism is located inside the panel cover, and the power steering device includes a hydraulic pump 33, a control valve 34 to which hydraulic fluid discharged from the hydraulic pump is supplied, and a steering cylinder 35 that is operated by the control valve, the control valve being supported by the front axle frame 72.

[0139] This configuration allows the automatic steering mechanism 37 to be positioned within the panel cover 78 near the steering shaft 31 without increasing the size of the panel cover 78. As a result, sufficient legroom and forward visibility for the driver can be ensured. Furthermore, the work vehicle 1 includes a steering wheel 30, a steering shaft 31 that rotatably supports the steering wheel, a vehicle body 3 that can be driven by either manual steering using the steering wheel or automatic steering of the steering wheel based on the planned driving line, and a steering switch 52 that is arranged around the steering shaft and pivots around a base end provided on the steering shaft side, swinging in a first direction for switching the start or end of automatic steering and in a second direction for setting the start and end points of a driving reference line that serves as the basis for the planned driving line.

[0140] This configuration offers excellent operability because, simply by changing the direction of oscillation of the steering selector switch 52, it is possible to switch the start or end of automatic steering and set the start and end points of the reference line that serves as the basis for the planned driving line. Furthermore, compared to cases where multiple switches are provided as the steering selector switch 52, the installation space required for the steering selector switch 52 can be reduced.

[0141] Furthermore, the steering selector switch 52 has a first direction of oscillation that is upward or downward, and a second direction of oscillation that is forward or backward. This configuration allows for switching the start or end of automatic steering, as well as setting the start and end points of the reference line that serves as the basis for the planned driving line, by swinging the steering switch 52 upward, downward, forward, or backward, resulting in excellent operability.

[0142] Furthermore, the steering selector switch 52 commands the start of automatic steering by swinging downwards, commands the end of automatic steering by swinging upwards, sets the starting point of the driving reference line by swinging backwards, and sets the ending point of the driving reference line by swinging forwards. This configuration allows for easy and reliable operation of starting automatic steering, ending automatic steering, setting the starting point of the driving reference line, and setting the ending point of the driving reference line.

[0143] Furthermore, it is equipped with a setting switch 51 located around the steering shaft 31, which switches to a setting mode that performs at least the settings before the start of automatic steering. With this configuration, in addition to the steering selector switch 52, the setting switch 51 is arranged around the steering shaft 31, allowing for a variety of switches while minimizing the space required for their placement.

[0144] The system 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 positioned around the steering shaft 31 and corrects the position detected by the position detection device 40. With this configuration, the steering selector switch 52, setting switch 51, and correction switch 53 are concentrated around the steering shaft 31, allowing for a wide variety of switches while minimizing the space required for their placement.

[0145] Furthermore, the system includes a screen switching switch 54 positioned around the steering shaft 31, which selectively switches the display on the display device 45 between a first screen Q1 that displays the driving status in setting mode and a second screen Q2 that explains the setting operations in setting mode. With this configuration, in addition to the steering selector switch 52, setting switch 51, and correction switch 53, the screen selector switch 54 is also clustered around the steering shaft 31. Therefore, it is possible to have a wide variety of switches while minimizing the space required for their placement.

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

[0147] With this configuration, the vibration damping member 64 suppresses the transmission of vibrations from the vehicle body 3, etc., to the inertial measuring device 42. As a result, the measurement error of the inertial measuring device 42 can be reduced, making it possible to perform automatic steering accurately. Furthermore, the vehicle includes a drive unit (e.g., a transmission 5) that drives the vehicle body and a housing (e.g., a transmission case 74) that covers the drive unit, and the support member 65 supports the inertial measuring device 42 in the housing via a vibration-damping member 64.

[0148] With this configuration, the vibration-damping member 64 suppresses the transmission of vibrations caused by the drive unit to the inertial measuring device 42. As a result, the measurement error of the inertial measuring device 42 can be reduced. Furthermore, the housing 74 is equipped with a support plate 66, and the support member 65 has a mounting portion 65a positioned below the support plate 66 to which the inertial measuring device 42 is attached, and a fixing portion 65b that rises from the mounting portion 65a and is fixed to the support plate 66 via the vibration damping member 64.

[0149] With this configuration, the inertial measuring device 42 can be suspended below a support plate 66 attached to the housing 74, and the vibration-damping member 64 can be installed interposed between it and the support plate 65. Therefore, the vibration-damping member 64 can effectively prevent vibrations from being transmitted to the inertial measuring device 42. In addition, space for the driver's seat or the like can be secured above the support plate 66.

[0150] Furthermore, the vehicle body 3 is equipped with a driver's seat 10, and the support plate 66 supports the driver's seat from below. With this configuration, the inertial measuring device 42 can be positioned below the driver's seat 10 via a support plate 66. Therefore, the inertial measuring device 42 can be positioned closer to the center of gravity of the vehicle body 3, improving the measurement accuracy of the inertial measuring device 42.

[0151] Furthermore, the fixing portion 65b is fixed to the support plate 66 by bolts B3, and the vibration-damping member 64 is interposed between the bolts and the fixing portion, and between the fixing portion and the support plate. With this configuration, the vibration damping member 64 can reliably prevent vibrations from the support plate 66 from being transmitted to the inertial measuring device 42 via the support member 65. Furthermore, the housing is the transmission case 74, and the support plate 66 is attached to the top of the transmission case.

[0152] With this configuration, the support plate 66 is attached to a highly rigid transmission case, which suppresses vibrations of the support plate 66 to which the support member 65 is fixed, thereby improving the measurement accuracy of the inertial measuring device 42. Furthermore, the support plate 66 has an opening 66c provided above the inertial measuring device 42, and the inertial measuring device is exposed through the opening.

[0153] This configuration allows for easy attachment and detachment of the inertial measuring device 42 using the opening 66c. Furthermore, by allowing the upper part of the inertial measuring device 42 to protrude from the opening 66c, the space occupied by the inertial measuring device 42 in the thickness direction (vertical direction) can be reduced. Although one embodiment of the present invention has been described above, the embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than by the foregoing description, and all modifications within the meaning and scope equivalent to the claims are intended to be included. [Explanation of Symbols]

[0154] 1. Work vehicle (tractor) 3. Vehicle Body 30 Steering Wheel 31 Steering shaft 52 Steering selector switch 81 Shuttle Lever

Claims

1. The steering wheel and A steering shaft that rotatably supports the steering handle, A vehicle body capable of driving by either manual steering using the steering wheel or automatic steering of the steering wheel based on the planned driving line, A steering selector switch is positioned around the steering shaft and switches the start or end of the automatic steering; Equipped with, The steering selector switch can be operated in at least two directions from the neutral position: up, down, forward, and backward. When the steering switch is operated from the neutral position to the first predetermined direction of the two directions, the starting point of the automatic steering driving reference line is set. A tractor in which automatic steering is initiated when the steering switch is operated from the neutral position to the second predetermined direction among the two directions.

2. The vehicle is equipped with a shuttle lever for operating the vehicle body to switch the direction of travel, The tractor according to claim 1, wherein the steering switch is arranged in the same direction as the shuttle lever with respect to the steering shaft.

3. The tractor according to claim 2, wherein the gripping portion of the steering changeover switch is positioned closer to the steering handle than the gripping portion of the shuttle lever.

4. The steering selector switch is The oscillation in the first direction is an upward or downward oscillation, A tractor according to any one of claims 1 to 3, wherein a downward swing commands the start of automatic steering, and an upward swing commands the end of automatic steering.

5. The steering selector switch is The oscillation in the second direction is an oscillation forward or backward, A tractor according to any one of claims 1 to 4, wherein the starting point of the driving reference line is set by swinging backward, and the ending point of the driving reference line is set by swinging forward.

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