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 has been 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 a steering device, an engine rotation control means, a transmission means, and a control unit for controlling these, and is capable of automatic driving by controlling the steering drive means, the engine rotation control means, and the transmission means so as to travel along a set route based on the position of the vehicle body. It also has an automatic driving mode and a manual driving mode that enables the vehicle body to 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 is provided with an automatic / manual changeover switch serving 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 such prior art, and an object thereof is to provide a work vehicle (tractor) that can surely prevent malfunction of a plurality of switches related to automatic steering.

Means for Solving the Problems

[0006] A tractor according to an aspect of the present invention includes a steering wheel, a steering shaft that rotatably supports the steering wheel, a vehicle body that can travel by either manual steering by the steering wheel or automatic steering of the steering wheel based on a planned travel line, a steering motor that rotates the steering wheel during the automatic steering, a steering changeover switch that is disposed around the steering shaft and switches the start or end of the automatic steering, an automatic steering mechanism that performs automatic steering of the vehicle body, and a control device that controls the steering motor. The automatic steering mechanism has a gear mechanism including a gear provided on the steering shaft and meshing with the steering shaft, and a gear provided on the rotation shaft of the steering motor and meshing with the rotation shaft. The steering changeover switch, the control device, and the gear mechanism are disposed below the steering wheel.

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

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

[0009] Preferably, the steering motor, the gear mechanism, and the control device are arranged side by side along the axial direction of the steering shaft in a side view. Preferably, the control device is arranged on the opposite side of the steering motor across the gear mechanism in a side view in the axial direction of the steering shaft.

[0010] Preferably, the tractor includes a display device capable of displaying operation information of the tractor and a panel cover that supports the display device, and the steering motor, the gear mechanism, and the control device are arranged inside the panel cover. Preferably, the control device has a housing and a circuit board arranged inside the housing. The housing is in the shape of a rectangular parallelepiped and is arranged vertically inside the panel cover such that the shortest side faces the vehicle body width direction or substantially the vehicle body width direction.

Advantages of the Invention

[0011] According to the above tractor, incorrect operations of a plurality of switches related to automatic steering can be reliably prevented.

Brief Description of the Drawings

[0012]

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Mode for Carrying Out the Invention

[0013] Hereinafter, embodiments of the present invention will be described with reference to the drawings. <Schematic of Work Vehicle> FIG. 28 is a side view showing an embodiment of a work vehicle 1, and FIG. 29 is a plan view showing an embodiment of the work vehicle 1. In this embodiment, the work vehicle 1 is a tractor. However, the work vehicle 1 is not limited to a tractor, and may be an agricultural machine (agricultural vehicle) such as a combine or a transplanter, or a construction machine (construction vehicle) such as a loader working machine.

[0014] Hereinafter, the front side (in the direction of arrow A1 in FIG. 28) of the driver sitting in the driver's seat 10 of the tractor (work vehicle) 1 will be described as the front, the rear side (in the direction of arrow A2 in FIG. 28) as the rear, the left side (in the direction of arrow B1 in FIG. 29) as the left, and the right side (in the direction of arrow B2 in FIG. 29) as the right. Also, the horizontal direction (in the direction of arrow B3 in FIG. 29), which is the direction orthogonal to the front-rear direction of the tractor 1, will be described as the vehicle body width direction.

[0015] As shown in FIG. 28, the tractor 1 includes a vehicle body 3, a prime mover 4, and a transmission 5. The vehicle body 3 has a traveling device 7 and is capable of traveling. The traveling device 7 is a device having front wheels 7F and rear wheels 7R. The front wheels 7F may be of a tire type or a crawler type. Also, the rear wheels 7R may be of a tire type or a crawler type. The prime mover 4 is a diesel engine, an electric motor, etc., and in this embodiment, it is composed of a diesel engine. The transmission 5 can switch the driving force of the traveling device 7 by shifting, and can also switch the forward and reverse of the traveling device 7. A driver's seat 10 is provided on the vehicle body 3.

[0016] Also, at the rear of the vehicle body 3, a connecting portion 8 composed of a three-point link mechanism or the like is provided. An operating device can be attached to and detached from the connecting portion 8. By connecting the operating device to the connecting portion 8, the vehicle body 3 can tow the operating device. The operating device includes a tilling device for tilling, a fertilizer spraying device for spraying fertilizer, a pesticide spraying device for spraying pesticides, a harvesting device for harvesting, a mowing device for mowing grass or the like, a spreading device for spreading grass or the like, a grass collecting device for collecting grass or the like, a forming device for forming grass or the like, and the like.

[0017] As shown in FIG. 1, the transmission 5 includes a main shaft (propulsion shaft) 5a, a main transmission portion 5b, a sub-transmission portion 5c, a shuttle portion 5d, a PTO power transmission portion 5e, and a front transmission portion 5f. The propulsion shaft 5a is rotatably supported by the housing case (transmission case) of the transmission 5, and power from the crankshaft of the engine 4 is transmitted to the propulsion shaft 5a. The main transmission portion 5b has a plurality of gears and a shifter for changing the connection of the gears. The main transmission portion 5b changes (shifts) the rotation input from the propulsion shaft 5a by appropriately changing the connection (meshing) of the plurality of gears with the shifter and outputs it.

[0018] The sub-transmission portion 5c, like the main transmission portion 5b, has a plurality of gears and a shifter for changing the connection of the gears. The sub-transmission portion 5c appropriately changes the connection (meshing) of the plurality of gears with the shifter It changes (shifts) the rotation input from the main transmission section 5b and outputs it. The shuttle section 5d has a shuttle shaft 12 and a forward / reverse switching section 13. Power output from the auxiliary transmission section 5c is transmitted to the shuttle shaft 12 via gears or the like. The forward / reverse switching section 13 is composed of, for example, a hydraulic clutch or the like, and switches the rotational direction of the shuttle shaft 12, that is, the forward and reverse of the tractor 1, 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 a rear axle 21R to which the rear wheels 7R are attached.

[0019] The PTO power transmission section 5e has a PTO drive shaft 14 and a PTO clutch 15. The PTO drive shaft 14 is rotatably supported and power from the drive shaft 5a can be transmitted thereto. The PTO drive shaft 14 is connected to the PTO shaft 16 via gears or the like. The PTO clutch 15 is composed of, for example, a hydraulic clutch or the like, and switches between a state in which power of the drive shaft 5a is transmitted to the PTO drive shaft 14 and a state in which power of the drive shaft 5a is not transmitted to the PTO drive shaft 14 by engaging and disengaging the hydraulic clutch.

[0020] The front transmission section 5f has a first clutch 17 and a second clutch 18. The first clutch 17 and the second clutch are capable of transmitting power from the drive shaft 5a. For example, power of 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-wheel differential device 20F, and the front-wheel differential device 20R rotatably supports a front axle 21F to which the front wheels 7F are attached.

[0021] The first clutch 17 and the second clutch 18 are constituted by a hydraulic clutch or the like. An oil passage is connected to the first clutch 17, and the oil passage is connected to a first operating valve 25 to which hydraulic oil discharged from a hydraulic pump is supplied. The first clutch 17 is switched between a connected state and a disconnected state according to the opening degree of the first operating valve 25. An oil passage is connected to the second clutch 18, and the oil passage is connected to a second operating valve 26. The second clutch 18 is switched between a connected state and a disconnected state according to the opening degree of the second operating valve 26. The first operating valve 25 and the second operating valve 26 are, for example, two-position switching valves with solenoid valves, and are switched to a connected state or a disconnected state by exciting or demagnetizing the solenoids of the solenoid valves.

[0022] When the first clutch 17 is in the disconnected state and the second clutch 18 is in the connected state, the power of the shuttle shaft 12 is transmitted to the front wheels 7F through the second clutch 18. Thereby, four-wheel drive (4WD) in which the front wheels and the rear wheels are driven by power and the rotational speeds of the front wheels and the rear wheels are substantially the same (4WD constant speed state). On the other hand, when the first clutch 17 is in the connected state and the second clutch 18 is in the disconnected state, four-wheel drive is achieved and the rotational speed of the front wheels becomes faster than the rotational speed of the rear wheels (4WD speed increasing state). Further, when the first clutch 17 and the second clutch 18 are in the connected state, since the power of the shuttle shaft 12 is not transmitted to the front wheels 7F, two-wheel drive (2WD) in which the rear wheels are driven by power is achieved. <Outline of the position detection device> The tractor 1 is provided 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) by a satellite positioning system (positioning satellite) such as D-GPS, GPS, GLONASS, Beidou, Galileo, or QZSS. That is, the position detection device 40 receives a received signal (position of the positioning satellite, transmission time, correction information, etc.) transmitted from the positioning satellite, and detects a position (for example, latitude and longitude) based on the received signal. 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 or the like and receives a received signal transmitted from a positioning satellite, and is attached to the vehicle body 3 separately from the inertial measurement device 42. In this embodiment, the receiving device 41 is attached to a rope 61 provided on the vehicle body 3. Note that the attachment location of the receiving device 41 is not limited to the embodiment. The inertial measurement device 42 has an acceleration sensor that detects acceleration, a gyro sensor that detects angular velocity, and the like. It is provided below the vehicle body 3, for example, below the driver's seat 10, and the inertial measurement device 42 can detect the roll angle, pitch angle, yaw angle, etc. of the vehicle body 3. <Overview of Steering Device, Manual Steering, and Automatic Steering> As shown in FIG. 1, the tractor 1 is provided with a steering device 11. The steering device 11 is a device capable of performing manual steering for steering the vehicle body 3 by the operation of the driver and automatic steering for automatically steering the vehicle body 3 without depending on the operation of the driver.

[0024] The steering device 11 has a steering wheel 30 and a steering shaft 31 that rotatably supports the steering wheel 30. Further, the steering device 11 has an auxiliary mechanism (power steering device) 32. The auxiliary mechanism 32 assists the manual steering of the steering wheel 30. More specifically, the auxiliary mechanism 32 assists the rotation of the steering shaft 31 (steering wheel 30) by hydraulic pressure or the like. The auxiliary mechanism 32 includes a hydraulic pump 33, a control valve 34 to which the hydraulic oil discharged from the hydraulic pump 33 is supplied, and a steering cylinder 35 that is operated by the control valve 34. The control valve 34 is, for example, a three-position switching valve that can be switched by the movement of a spool or the like, and switches corresponding to 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, if the driver holds the steering wheel 30 and operates it in one direction or the other, the switching position and the opening degree of the control valve 34 are switched corresponding to the rotation direction of the steering wheel 30, and the steering cylinder 35 expands and contracts left or right according to the switching position and the opening degree of the control valve 34, so that the steering direction of the front wheels 7F can be changed. That is, the vehicle body 3 can change its traveling direction left or right by manually steering the steering wheel 30.

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

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

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

[0029] Also, after starting automatic steering, if the driver operates the steering switch 52 at an arbitrary location, automatic steering can be terminated. That is, the end point of the planned travel line L2 can be set by terminating automatic steering by operating the steering switch 52. In other words, the length from the start point to the end point of the planned travel line L2 can be set to be longer or shorter than the travel reference line L1. In other words, the planned travel line L2 is not associated with the length of the travel reference line L1, and with the planned travel line L2, it is possible to travel while automatically steering a distance longer than the length of the travel reference line L1.

[0030] As shown in FIG. 1, the steering device 11 has an automatic steering mechanism 37. The automatic steering mechanism 37 is a mechanism for automatically steering 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 inertial measurement device 42. The automatic steering mechanism 37 includes a steering motor 38 and a gear mechanism 39. The steering motor 38 is a motor whose rotation direction, rotation speed, rotation angle, etc. can be controlled based on the vehicle body position. The gear mechanism 37 includes a gear provided on the steering shaft 31 and rotating together with the steering shaft 31, and a gear provided on the rotation shaft of the steering motor 38 and rotating together with the rotation shaft. When the rotation shaft of the steering motor 38 rotates, the steering shaft 31 automatically rotates (pivots) via the gear mechanism 37, and the steering direction of the front wheels 7F can be changed so that the vehicle body position coincides with the planned travel line L2. <Outline of the display device> As shown in FIGS. 1 and 12, the tractor 1 includes a display device 45. The display device 45 is a device capable of displaying various information regarding the tractor 1, and is capable of displaying at least the driving information of the tractor 1. The display device 45 is provided in front of the driver's seat 10. <Outline of the setting switch and the steering changeover switch> As shown in FIG. 1, the tractor 1 includes a setting switch 51. The setting switch 51 is a switch for switching to a setting mode for performing at least settings before starting automatic steering. The setting mode is a mode for performing various settings regarding the automatic steering before starting the automatic steering, and is, for example, a mode for setting the start point and the end point of the travel reference line L1.

[0031] The setting switch 51 can be switched between ON and OFF. When it is ON, it outputs a signal indicating that the setting mode is valid, and when it is OFF, it outputs a signal indicating that the setting mode is invalid. Also, when the setting switch 51 is ON, it outputs a signal indicating that the setting mode is valid to the display device 45, and when it is OFF, it outputs a signal indicating that the setting mode is invalid to the display device 45.

[0032] The tractor 1 is equipped with a steering switch 52. The steering switch 52 is a switch for switching the start or end of automatic steering in the setting mode. Specifically, the steering switch 52 can be switched from the neutral position upward, downward, forward, and backward. When it is switched downward from the neutral position in a state where the setting mode is valid, it outputs the start of automatic steering. When it is switched upward from the neutral position in a state where the setting mode is valid, it outputs the end of automatic steering. Also, when the steering switch 52 is switched backward from the neutral position in a state where the setting mode is valid, it outputs setting the current vehicle body position to the starting point P10 of the travel reference line L1. When the steering switch 52 is switched forward from the neutral position in a state where the setting mode is valid, it outputs setting the current vehicle body position to the end point P11 of the travel reference line L1. <Overview of the correction switch> The tractor 1 is equipped with a correction switch 53. The correction switch 53 is a switch for correcting the vehicle body position (latitude, longitude) measured by the position detection device 40. That is, the correction switch 53 is a switch for correcting the vehicle body position (referred to as the calculated vehicle body 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 measurement device 42.

[0033] The correction switch 53 is composed of a push switch that can be pressed or a slide switch that can be slid. Hereinafter, the cases where the correction switch 53 is a push switch and a slide switch respectively will be described. When the correction switch 53 is a push switch, the correction amount is set based on the number of operations of the push switch. The correction amount is determined by the formula: correction amount = number of operations × correction amount per operation. For example, as shown in FIG. 3A, each time the push switch is operated, the correction amount increases by several centimeters or several tens of centimeters. The number of operations of the push switch 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] Also, when the correction switch 53 is a slide switch, the correction amount is set based on the operation amount (displacement amount) of the slide switch. For example, the correction amount is determined by the formula: correction amount = displacement amount from a predetermined position. For example, as shown in FIG. 3B, each time the displacement amount of the slide switch increases by 5 mm, the correction amount increases by several centimeters or several tens of centimeters. The operation amount (displacement amount) 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 amount. Note that the above-described method of increasing the correction amount and the rate of increase are not limited to the above-described numerical values.

[0035] Specifically, as shown in FIGS. 4A and 4B, the correction switch 53 includes a first correction unit 53A and a second correction unit 53B. The first correction unit 53A is a part that commands correction of the vehicle body position corresponding to one side in the width direction of the vehicle body 3 (the vehicle body width direction), that is, the left side. The second correction unit 53B is a part that commands correction of the vehicle body position corresponding to the other side in the width direction of the vehicle body 3, that is, the right side.

[0036] As shown in FIG. 4A, when the correction switch 53 is a push switch, the first correction unit 53A and the second correction unit 53B are ON or OFF switches that automatically return every time an operation is performed. The switch constituting the first correction unit 53A and the switch constituting the second correction unit 53B are integrated. Note that the switch constituting the first correction unit 53A and the switch constituting the second correction unit 53B may be arranged apart from each other. As shown in FIG. 3A, every 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, every time the second correction unit 53B is pressed, the correction amount corresponding to the right side of the vehicle body 3 (right correction amount) increases.

[0037] As shown in FIG. 4B, when the correction switch 53 is a slide switch, the first correction unit 53A and the second correction unit 53B include a knob portion 55 that moves left or right along the longitudinal direction of the long hole. When the correction switch 53 is a slide switch, the first correction unit 53A and the second correction unit 53B are arranged apart from each other in the width direction. As shown in FIG. 3B, when the knob portion 55 is gradually displaced to the left from a predetermined reference position, the left correction amount increases according to the displacement amount. Also, when the knob portion 55 is gradually displaced to the right from a predetermined reference position, the right correction amount increases according to the displacement amount. Note that, as shown in FIG. 4B, in the case of a slide switch, the first correction unit 53A and the second correction unit 53B may be integrally formed, the reference position of the knob portion 55 may be set at the center, the left correction amount may be set when moving to the left from the reference position, and the right correction amount may be set when moving the knob portion 55 to the right from the intermediate position. Next, the relationship between the correction amounts (left correction amount, right correction amount) by the correction switch 53, the planned travel route L2, and the behavior (travel locus) of the tractor 1 (vehicle body 3) will be described.

[0038] FIG. 5A shows a state where the calculated vehicle body position W1 has shifted to the right while going straight during automatic steering. As shown in FIG. 5A, when the automatic steering is started, if the position of the actual tractor 1 (vehicle body 3) (actual position W2) coincides with the calculated vehicle body position W1, and the actual position W2 coincides with the planned travel route L2, the tractor 1 travels along the planned travel route L2. That is, in the section P1 where there is no error in the positioning of the position detection device 40 and the vehicle body position (calculated vehicle body position W1) detected by the position detection device 40 is the same as the actual position W2, the tractor 1 travels along the planned travel route L2. Incidentally, when there is no error in the positioning of the position detection device 40 and no correction is performed, the calculated vehicle body position W1 and the corrected vehicle body position (corrected vehicle body position) W3 corrected by the correction amount have the same value. The corrected vehicle body position W3 is given by corrected vehicle body position W3 = calculated vehicle body position W1 - correction amount.

[0039] Here, in the vicinity of position P20, even though the actual position W2 is not deviated from the planned travel route L2, due to various influences, an error occurs in the positioning of the position detection device 40, and the vehicle body position W1 detected by the position detection device 40 is shifted to the right with respect to the planned travel route L2 (actual position W2), and it is assumed that the deviation amount W4 is maintained. Then, the tractor 1 determines that a deviation has occurred between the calculated vehicle body position W1 and the planned travel route L2, and steers the tractor 1 to the left so as to eliminate the deviation amount W4 between the calculated vehicle body position W1 and the planned travel route L2. Then, the actual position W2 of the tractor 1 shifts to the planned travel route L2 by the left steering. After that, it is assumed that the driver notices that the tractor 1 has deviated from the planned travel route L2 and steers the second correction unit 53B at position P21 to increase the right correction amount from zero. A right correction amount is added to the calculated vehicle body position W1, and the corrected vehicle body position (corrected vehicle body position) W3 can be made substantially the same as the actual position W2. That is, by setting the right correction amount by the second correction unit 53B, the vehicle body position of the position detection device 40 can be corrected in the direction of eliminating the deviation amount W4 generated in the vicinity of position P20. As shown in position P21 of FIG. 5A, when the actual position W2 of the tractor 1 is separated from the planned travel route L2 to the left after the correction of the vehicle body position, the tractor 1 is steered to the right, and the actual position W2 of the tractor 1 can be made to coincide with the planned travel route L2.

[0040] FIG. 5B shows a state where the calculated vehicle body position W1 is shifted to the left during straight travel while the automatic steering is in progress. As shown in FIG. 5B, in a state where the automatic steering has been started, when the actual position W2 and the calculated vehicle body position W1 coincide with each other, and the actual position W2 and the planned travel route L2 coincide with each other, the tractor 1 travels along the planned travel route L2 as in FIG. 5A. That is, as in FIG. 5A, in the section P2 where there is no error in the positioning of the position detection device 40, the tractor 1 travels along the planned travel route L2. Also, as in FIG. 5A, the calculated vehicle body position W1 and the corrected vehicle body position W3 have the same value.

[0041] Here, at position P22, due to various influences, an error occurs in the positioning of the position detection device 40, and the vehicle body position W1 detected by the position detection device 40 is shifted to the left with respect to the actual position W2, and it is assumed that the shift amount W5 is maintained. Then, the tractor 1 steers the tractor 1 to the right so as to eliminate the shift amount W5 between the calculated vehicle body position W1 and the planned travel route L2. After that, it is assumed that the driver notices that the tractor 1 has deviated from the planned travel route L2, and the driver steers the first correction unit 53A at position P23 to increase the left correction amount from zero. Then, a left correction amount is added to the calculated vehicle body position W1, and the corrected vehicle body position (corrected vehicle body position) W3 can be made substantially the same as the actual position W2. That is, by setting the left correction amount by the first correction unit 53A, the vehicle body position of the position detection device 40 can be corrected in a direction to eliminate the shift amount W5 generated near position P22. As shown at position P23 in FIG. 5B, when the actual position W2 of the tractor 1 is separated from the planned travel route L2 to the right after the correction of the vehicle body position, the tractor 1 is steered to the left, and the actual position W2 of the tractor 1 can be made to coincide with the planned travel route L2. <Schematic of the control device> As shown in FIG. 1, the tractor 1 includes a plurality of control devices 60. The plurality of control devices 60 are devices that perform control of the traveling system, control of the working system, calculation of the vehicle body position, etc. in the tractor 1. The plurality of 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 measurement information (acceleration, angular velocity, etc.) measured by the inertial measurement device 42, and determines the vehicle body position based on the received information and the measurement information. For example, when the correction amount by the correction switch 53 is zero, that is, when the correction of the vehicle body position by the correction switch 53 is not commanded, the first control device 60A does not correct the calculated vehicle body position W1 calculated from the received information and the measurement information, and determines the calculated vehicle body position W1 as the vehicle body position to be used during automatic steering. On the other hand, when the correction of the vehicle body position by the correction switch 53 is commanded, the first control device 60A sets the correction amount of the vehicle body position based on either the number of operations of the correction switch 53 or the operation amount (displacement amount) of the correction switch 53, and determines the corrected vehicle body position W3 obtained by correcting the calculated vehicle body position W1 by the correction amount as the vehicle body position to be used during automatic steering.

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

[0044] As shown in FIG. 6, when the deviation between the vehicle body position and the planned travel line L2 is less than the threshold value, the second control device 60B maintains the rotation angle of the rotation shaft of the steering motor 38. When the deviation between the vehicle body position and the planned travel line L2 is equal to or greater than the threshold value and the tractor 1 is located on the left side of the planned travel line L2, the second control device 60B rotates the rotation shaft of the steering motor 38 so that the steering direction of the tractor 1 is to the right. When the deviation between the vehicle body position and the planned travel line L2 is equal to or greater than the threshold value and the tractor 1 is located on the right side of the planned travel line L2, the second control device 60B rotates the rotation shaft of the steering motor 38 so that the steering direction of the tractor 1 is to the left. In the above-described embodiment, the steering angle of the steering device 11 is changed based on the deviation between the vehicle body position and the planned travel line L2. However, when the azimuth of the planned travel line L2 and the azimuth (vehicle body azimuth) F1 of the traveling direction (travel direction) of the tractor 1 (vehicle body 3) are different, that is, when the angle θ of the vehicle body azimuth F1 with respect to the planned travel line L2 is equal to or greater than the threshold value, the second control device 60B may set the steering angle so that the angle θ is zero (the vehicle body azimuth F1 coincides with the azimuth of the planned travel line L2). Further, 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 azimuth (azimuth deviation θ). The setting of the steering angle in the automatic steering in the above-described embodiment is an example and is not limited.

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

[0046] The front axle frame 70 is disposed at the front portion of the vehicle body 3 and rotatably supports the axle (front axle) 21F of the front wheel 7F. Further, the front axle frame 70 supports the prime mover 4 and extends forward from the prime mover 4. The front axle frame 70, the flywheel housing 71, the clutch housing 72, the intermediate frame 73, and the transmission case 74 are integrally connected to form a highly rigid vehicle body frame.

[0047] The flywheel housing 71 is connected to the rear portion 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 portion of the clutch housing 72 and extends rearward from the clutch housing 72. The transmission case 74 is connected to the rear portion of the intermediate frame 73 and houses the transmission 5 and the rear wheel differential device 20R.

[0048] As shown in FIG. 7, the front axle frame 70 has a first frame 70A disposed on one side (left side) in the vehicle body width direction, a second frame 70B disposed on the other side (right side) in the vehicle body width direction, and a third frame 70C connecting the first frame 70A and the second frame 70B. As shown in FIGS. 7, 28, and 29, a weight 75 is mounted on the front end of the front axle frame 70. Further, a bonnet 76 is attached to the upper portion of the front axle frame 70.

[0049] The bonnet 76 covers the prime mover 4. Specifically, the bonnet 76 has an upper plate portion 76a that covers the upper part of the prime mover 4, a left plate portion 76b that covers the left side of the prime mover 4, a right plate portion 76c that covers the right side of the prime mover 4, and a front plate portion 76d that covers the front of the prime mover 4. A cover 77 for housing the steering shaft 31 and the like is provided at the rear portion of the bonnet 76. A 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 FIGS. 8 to 10, the outer periphery of the steering shaft 31 is covered by a steering post 80. The steering post 80 is cylindrical and extends along the axial direction of the steering shaft 31. As shown in FIGS. 8 and 9, the outer periphery of the steering post 80 is covered by a cover 77. The cover 77 is provided in front of the driver's seat 10. As shown in FIGS. 14, 28, and 29, the cover 77 includes a panel cover 78 and a column cover 79.

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

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

[0052] As shown in FIGS. 11 to 14, the upper plate portion 78a of the panel cover 78 has an attachment surface 78f to which the setting switch 51, the correction switch 53, and the screen switching switch 54 are attached. That is, the panel cover 78 is provided with the setting switch 51, the correction switch 53, and the screen switching switch 54. The attachment surface 78f is provided behind the support portion 78e and below the steering handle 30. The support portion 78e and the attachment surface 78f are continuously and integrally configured. The support portion 78e is located at the front portion of the upper plate portion 78a, and the attachment surface 78f is located at the rear portion of the upper plate portion 78a.

[0053] As shown in FIGS. 8, 9, 11, and 14, the attachment surface 78f is inclined so as to shift downward as it goes rearward. As shown in FIG. 12, the attachment 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 a region located on one side (left side) of the steering shaft 31. The second region 78f2 is a region located on the other side (right side) of the steering shaft 31. The third region 78f3 is a 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 attached to any of the three regions (the first region 78f1, the second region 78f2, and the third region 78f3) of the attachment 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 FIGS. 11 to 14, FIG. 28, and FIG. 29, a shuttle lever 81 protrudes from the left part (left plate part 78b) of the panel cover 78. The shuttle lever 81 protrudes leftward from the left part of the panel cover 78 and then extends upward. The shuttle lever 81 is a member that performs an operation to switch the traveling direction of the vehicle body 3. More specifically, by operating (swinging) the shuttle lever 81 forward, the forward / reverse switching unit 13 outputs forward driving force to the traveling device 7, and the traveling direction 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 driving force to the traveling device 7, and the traveling direction of the vehicle body 3 is switched to the reverse direction. When the shuttle lever 81 is in the neutral position, no power is output to the traveling device 7.

[0055] A gripping portion 81a for an operator to grip is provided at the tip (upper end portion) of the shuttle lever 81. As shown in FIG. 11, the gripping portion 81a is disposed to the left of the grip 30a of the steering handle 30. Also, the gripping portion 81a is above the mounting surface 78f of the panel cover 78 and is disposed at a position leftward and away from the mounting surface 78f. This prevents accidental contact with various switches (such as the setting switch 51) provided on the mounting surface 78f during operation of the shuttle lever 81, or accidental contact with the shuttle lever 81 during operation of various switches provided on the mounting surface 78f.

[0056] As shown in FIGS. 11 to 14, FIG. 28, and FIG. 29, the column cover 79 is disposed below the steering handle 30. As shown in FIGS. 8 and 9, the column cover 79 covers the periphery of the upper portion of the steering shaft 31 and the steering post 80. The column cover 79 is formed in a substantially square tube shape and protrudes upward from the mounting surface 78f of the panel cover 78. As shown in FIG. 12, the first region 78f1, the second region 78f2, and the third region 78f3 of the mounting surface 78f are disposed on one side (left side), the other side (right side), and the rear of the column cover 79, respectively. That is, 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 attached to the mounting surface 78f are disposed around the column cover 79.

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

[0058] Since the setting switch 51, the correction switch 53, and the screen switching switch 54 are located at positions away from the steering handle 30, it is possible to prevent unintended contact with the setting switch 51, the correction switch 53, and the screen switching switch 54 during the operation of the steering handle 30. Also, it is possible to prevent unintended contact with the steering handle 30 during the operation of the setting switch 51, the correction switch 53, and the screen switching switch 54. Therefore, it is possible to prevent unintended switching to automatic steering due to an incorrect operation. <Arrangement of Switches> Next, the arrangement of the setting switch 51, the steering switch 52, the correction switch 53, and the screen switching switch 54 will be described.

[0059] As shown in FIGS. 11 to 13, the setting switch 51, the steering changeover switch 52, the correction switch 53, and the screen changeover switch 54 are arranged around the steering shaft 31. Hereinafter, the specific arrangements of the setting switch 51, the steering changeover switch 52, the correction switch 53, and the screen changeover switch 54 will be described. As shown in FIGS. 11 to 13, the setting switch 51 is arranged on one side (left side) of the steering shaft 31 in the vehicle body width direction. Further, the setting switch 51 is arranged behind the steering shaft 31 in the front-rear direction. That is, the setting switch 51 is arranged on the left and rear (diagonal left rear) of the steering shaft 31. In the case of this embodiment, the setting switch 51 is composed of a push switch.

[0060] In terms of the positional relationship with the column cover 79, the setting switch 51 is arranged on the left and rear (diagonal left rear) of the column cover 79. In terms of the positional relationship with the mounting surface 78f of the panel cover 78, the setting switch 51 is arranged at the rear part of the first region 78f1 of the mounting surface 78f. Also, in terms of the positional relationship with the display device 45, the setting switch 51 is arranged behind the display device 45 (on the driver's seat 10 side). Thereby, the driver can easily and accurately operate the setting switch 51 while checking the display device 45 without changing the posture of sitting on the driver's seat 10.

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

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

[0063] A grip portion 52a for the operator to grip is provided at the tip end (left end portion) of the steering changeover switch 52. As shown in FIGS. 11, 14, etc., the grip portion 52a is disposed below the grip 30a of the steering handle 30 and in the vicinity of the grip 30a. Further, as shown in FIG. 13, when viewed in the axial direction of the steering shaft 31, the grip portion 52a overlaps with the grip 30a of the steering handle 30. Thereby, in a state where the grip 30a of the steering handle 30 is gripped, the steering changeover switch 52 can be operated by extending a finger to the grip portion 52a.

[0064] Here, the grip portion 81a of the shuttle lever 81 is separated downward and leftward from the grip 30a of the steering handle 30, and is disposed at a position where a finger cannot reach in a state where the grip 30a is gripped. Therefore, when operating the steering changeover switch 52 in a state where the grip 30a is gripped, it is possible to prevent the shuttle lever 81 from being unintentionally operated. Also, when operating the shuttle lever 81, it is possible to prevent the steering changeover switch 52 from being unintentionally operated.

[0065] As shown in FIG. 14, the steering changeover switch 52 is swingable in a first direction (directions indicated by arrow C1 and arrow C2) for switching the start or end of the automatic operation, and a second direction (directions indicated by arrow D1 and arrow D2) for setting the start point and the end point of the travel reference line serving as a reference for the planned travel line. The rocking in the first direction is a rocking upward or downward from the neutral position. The rocking in the second direction is a rocking forward or backward from the neutral position. When the setting mode is valid, the steering changeover switch 52 commands (outputs) the start of the automatic steering by rocking downward (in the direction of arrow C1) from the neutral position, and commands (outputs) the end of the automatic steering by rocking upward (in the direction of arrow C2) from the neutral position. Further, when the setting mode is valid, the steering changeover switch 52 sets the start point of the traveling reference line by rocking backward (in the direction of arrow D1) from the neutral position, and sets the end point of the traveling reference line by rocking forward (in the direction of arrow D2) from the neutral position.

[0066] As shown in FIGS. 11 to 13, the correction switch 53 is arranged on the other lateral side (right side) of the steering shaft 31 in the vehicle body width direction. Further, the correction switch 53 is arranged behind the steering shaft 31 in the front-rear direction. That is, the correction switch 53 is arranged on the right side and behind (diagonally right-rear) of the steering shaft 31. In the case of the present embodiment, the correction switch 53 is composed of a push switch. In terms of the positional relationship with the column cover 79, the correction switch 53 is arranged on the right side and behind (diagonally right-rear) of the column cover 79. In terms of the positional relationship with the mounting surface 78f of the panel cover 78, the correction switch 53 is arranged at the rear part of the second region 78f2 of the mounting surface 78f.

[0067] Further, in terms of the positional relationship with the display device 45, the correction switch 53 is arranged behind the display device 45 (on the driver's seat 10 side). Thereby, the driver can easily and accurately operate the correction switch 53 while checking the display device 45 without changing the posture of sitting on the driver's seat 10. As shown in FIG. 13, when viewed from the axial direction of the steering shaft 31, the correction switch 53 does not overlap with the grip 30a of the steering wheel 30. Specifically, when viewed from the axial direction of the steering shaft 31, the correction switch 53 is arranged inside the grip 30a of the steering wheel 30 (on the side closer to the axis of the steering shaft 31).

[0068] The screen switching switch 54 switches the display of the display device 45 between a first screen Q1 that displays the driving status (driving information) in the setting mode and a second screen Q2 that explains the setting operation in the setting mode. FIG. 27 shows an example of the first screen Q1 and the second screen Q2 displayed on the display device 45. As shown in FIGS. 12 and 13, the screen switching switch 54 is arranged on the other side (right side) of the steering shaft 31 in the vehicle body width direction. Also, the screen switching switch 54 is arranged in front of the steering shaft 31 in the front-rear direction. That is, the screen switching switch 54 is arranged on the right side and in front (diagonally right front) of the steering shaft 31. In the case of this embodiment, the screen switching switch 54 is composed of a push switch. In terms of the positional relationship with the column cover 79, the screen switching switch 54 is arranged on the right side and in front (diagonally right front) of the column cover 79. In terms of the positional relationship with the mounting surface 78f of the panel cover 78, the screen switching switch 54 is arranged at the front part 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 FIG. 13, when viewed from the axial direction of the steering shaft 31, the screen switching switch 54 does not overlap with the grip 30a of the steering wheel 30. Specifically, when viewed from the axial direction of the steering shaft 31, the screen switching switch 54 is arranged inside (the side closer to the axis of the steering shaft 31) the grip 30a of the steering wheel 30.

[0070] As described above, the setting switch 51, the steering changeover switch 52, the correction switch 53, and the screen changeover switch 54 are collectively arranged around the steering shaft 31. Therefore, the driver can clearly grasp the positions of the respective switches at a glance. In addition, the driver can operate each switch without changing the posture while remaining seated in the driver's seat 10. Therefore, the operability is good and incorrect operation can be prevented. Further, the harness (wiring) routed from each switch can be shortened.

[0071] Also, as shown in FIGS. 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 for operating a turn signal, a headlight, etc. provided in front of the vehicle body 3. The combination switch 82 is arranged around the steering shaft 31. Specifically, the combination switch 82 is arranged on one side (left side) of the steering shaft 31. In relation to the column cover 79, the combination switch 82 is arranged on one side (left side) of the column cover 79. Also, the combination switch 82 is arranged below the steering changeover switch 52 and in front of the setting switch 51.

[0072] As shown in FIG. 13, when viewed from the axial direction of the steering shaft 31, the combination switch 82 does not overlap with the grip 30a of the steering wheel 30. Specifically, when viewed from the axial direction of the steering shaft 31, the combination switch 82 is arranged inside the grip 30a of the steering wheel 30 (the side closer to the axis of the steering shaft 31).

[0073] Incidentally, regarding the arrangement of the various switches described above, the left - right positional relationship may be interchanged. That is, one side may be the left side and the other side may be the right side, or one side may be the right side and the other side may be the left side. Specifically, for example, the setting switch 51 and the steering changeover switch 52 may be arranged on the right side of the steering shaft 31, and the correction switch 53 may be arranged on the left side of the steering shaft 31. <Lift lever (pump lever), accelerator lever> As shown in FIGS. 11 to 13, the tractor 1 includes a lift lever 83 and an accelerator lever 84.

[0074] The lift lever 83 is a lever (pump lever) for raising and lowering the connecting portion 8. The lift lever 83 is disposed on the other lateral side (right side) of the steering shaft 31. The lift lever 83 is swingable about a base end portion provided on the steering shaft 31 side as a fulcrum. The base end portion of the lift lever 83 is provided inside the panel cover 78. The lift lever 83 protrudes upward on the other lateral side (right side) of the panel cover 78, and the tip portion is located on the other lateral side (right side) of the column cover 79.

[0075] As shown in FIG. 13, when the lift lever 83 is in the neutral position, it is located between the correction switch 53 and the screen switching switch 54 when viewed in 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 accidentally operated during the operation of the lift lever 83, and also prevents the lift lever 83 from being accidentally operated during the operation of the correction switch 53 and the screen switching switch 54.

[0076] As shown in FIGS. 12 and 13, a grip portion 83a for the operator to grip is provided at the tip portion (right end portion) of the lift lever 83. The grip portion 83a is disposed below the grip 30a of the steering handle 30 and in the vicinity of the grip 30a. As shown in FIG. 13, the grip portion 83a overlaps with the grip 30a when viewed in the axial direction of the steering shaft 31. Thus, with the grip 30a of the steering handle 30 being gripped, the lift lever 83 can be operated by extending a finger to the grip portion 83a.

[0077] The elevating lever 83 is arranged on the opposite side of the steering changeover switch 52 across the steering shaft 31 in the vehicle body width direction. Thereby, it is possible to prevent malfunction caused by the operator's hand contacting the elevating lever 83 when operating the steering changeover switch 52, or the operator's hand contacting the steering changeover switch 52 when operating the elevating lever 83. As shown in FIGS. 11 to 13, the accelerator lever 84 is arranged on the other side (right side) of the steering shaft 31. The accelerator lever 84 is swingable about a base end portion provided on the steering shaft 31 side as a fulcrum. The base end portion of the accelerator lever 84 is provided inside the panel cover 78. The accelerator lever 84 protrudes upward from the mounting surface 78f of the panel cover 78 on the other side of the column cover 79. More specifically, the accelerator lever 84 protrudes from the mounting surface 78f of the panel cover 78 in front of the correction switch 53 and behind the screen changeover switch 54. The accelerator lever 84 extends rightward (in a direction away from the column cover 79) after protruding upward from the mounting surface 78f.

[0078] A grip portion 84a for the operator to grip is provided at the tip end portion (right end portion) of the accelerator lever 84. The grip portion 84a is located below the grip 30a of the steering wheel 30. As shown in FIG. 13, the grip portion 84a overlaps the grip 30a in the axial direction of the steering shaft 31. The grip portion 84a of the accelerator lever 84 is located in front of and below the grip portion 83a of the elevating lever 83. <Arrangement of Automatic Steering Mechanism, etc.> Next, the arrangement of the automatic steering mechanism 37 and the like will be described.

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

[0080] The gear mechanism 39 of the automatic steering mechanism 37 includes a gear case 39a and a plurality of gears housed inside the gear case 39a. As shown in FIGS. 10 and 15, the gear case 39a is fixed to the upper end portion of the support post 85. The support post 85 is formed in a square tube shape and extends in the axial direction of the steering shaft 31. As shown in FIGS. 15 and 17, an upper plate 85a for supporting the gear case 39a from below is provided at the upper end portion of the support post 85. Incidentally, in FIG. 17, the gear case 39a is omitted and the internal gears are shown. As shown in FIG. 17, the lower portion of the steering shaft 31 passing through the upper plate 85a and the gear case 39a is inserted into the upper portion of the support post 85. As shown in FIGS. 8 to 10 and 15, the lower end portion of the support post 85 is fixed to the upper portion of the clutch housing 72 via a mounting stay 86 or the like.

[0081] The steering motor 38 and the gear mechanism 39 are integrally provided. Specifically, the housing of the steering motor 38 is fixed to the upper portion of the gear case 39a by bolts or the like. As shown in FIG. 10, the steering motor 38 and the gear mechanism 39 are arranged near the axis CL1 of the steering shaft 31. Specifically, the steering motor 38 and the gear mechanism 39 are arranged at a position closer to the axis CL1 of the steering shaft 31 than the outer edge of the grip 30a of the steering wheel 30 in the vehicle body width direction. In other words, the steering motor 38 and the gear mechanism 39 are arranged between a virtual line VL1 obtained by extending downward the outer end on one side in the vehicle body width direction of the grip 30a and a virtual line VL2 obtained by extending downward the outer end on the other side in the vehicle body width direction of the grip 30a in the vehicle body width direction.

[0082] As shown in FIGS. 17 and 18, the gear mechanism 39 has a first gear 391, a second gear 392, a third gear 393, and a fourth gear 394. The first gear 391 is attached to the output shaft (rotating shaft) of the steering motor 38. The second gear 392 is arranged in front of the steering shaft 31 and meshes with the first gear 391. The third gear 393 is arranged below the second gear 392 and is connected to the second gear 392 by a connecting shaft 390. The connecting shaft 390 is rotatably supported by a bearing 395 held in a 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 the rotation is transmitted from the first gear 391 to the second gear 392, and the connecting shaft 390 rotates. When the connecting shaft 390 rotates, the third gear 393 rotates, and the power of the rotation is transmitted to the steering shaft 31 via the fourth gear 394, and the steering shaft 31 rotates. In this way, the steering shaft 31 rotates by driving the steering motor 38. <Arrangement, etc. of the power steering device> Next, the arrangement, etc. of the power steering device 32 will be described.

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

[0085] The power steering unit 93 shown in FIG. 7 includes a control valve 34 and a steering cylinder (power cylinder) 35. The power steering unit 93 (control valve 34, steering cylinder 35) is supported by the front axle frame 70. The power steering unit 93 is located between the first frame 70A and the second frame 70B of the front axle frame 70. The power steering unit 93 is connected to the hydraulic pump 33 via a hydraulic hose (not shown). The hydraulic pump 33 is disposed 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 rod 95 is connected to the left and right front wheels 7F. When the steering wheel 30 is manually rotated (steered), this rotation is transmitted from the steering shaft 31 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 actuated (the spool moves). As a result, the hydraulic oil 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 rod 95 via the pitman arm 94, and the direction of the left and right front wheels 7F is changed by the movement of the tie rod 95.

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

[0088] When the automatic steering mechanism 37 and the power steering device 32 (for example, the control valve 34) are arranged in the vicinity, a large overall arrangement space is required. However, by arranging the automatic steering mechanism 37 and the power steering device 32 at separated positions, the arrangement space for each can be small and a large overall arrangement space is not required. <Arrangement of the First Control Device, Second Control Device, etc.> As shown in FIGS. 8 and 9, the first control device 60A and the second control device 60B are arranged inside the panel cover 78. As shown in FIGS. 10 and 16, the first control device 60A is arranged on one side (left side) of the steering shaft 31. The second control device 60B is arranged on the other side (right side) of the steering shaft 31. The first control device 60A and the second control device 60B are connected by a harness (not shown) capable of transmitting electrical signals.

[0089] In this way, since the first control device 60A and the second control device 60B are separately configured and arranged separately on one side (left side) and the other side (right side) of the steering shaft 31, the first control device 60A and the second control device 60B are miniaturized compared to the case of an integrated control device and can be arranged at a position near the steering shaft 31. Therefore, the first control device 60A and the second control device 60B can be reliably accommodated in the panel cover 78. Further, since the first control device 60A and the second control device 60B are arranged separately, it is possible to prevent the other control device from being adversely affected by the heat generated from one control device.

[0090] The first control device 60A and the second control device 60B each have a housing and a circuit board disposed inside the housing. The circuit board is composed of various electrical and electronic components such as semiconductors and can perform the above-described control and the like. The housing is in the shape of a rectangular parallelepiped and is arranged vertically. Specifically, for the housing of the first control device 60A, among the three sides (length, width, and height), the shortest side faces the vehicle body width direction, and the longest side faces the vertical direction. For the housing of the second control device 60B, among the three sides, the shortest side faces the substantially vehicle body width direction, and the longest side faces the substantially front-rear direction. In this way, for the first control device 60A and the second control device 60B, the shortest side faces the vehicle body width direction or the substantially vehicle body width direction. As a result, the occupied area in the vehicle body width direction of the first control device 60A and the second control device 60B becomes smaller, so that the first control device 60A and the second control device 60B can be surely accommodated in the panel cover 78. Also, since the panel cover 78 can be made smaller, sufficient foot space and forward visibility for the driver seated in the driver's seat 10 can be ensured. Further, since the first control device 60A and the second control device 60B can be arranged close to each other, the harness connecting the first control device 60A and the second control device 60B can be shortened, and it becomes less susceptible to the influence of noise.

[0091] As shown in FIG. 10, the first control device 60A is arranged at a position closer to the axis CL1 of the steering shaft 31 than the outer edge of the grip 30a of the steering wheel 30 in the vehicle body width direction. In other words, the first control device 60A is arranged at a position closer to the axis CL1 than a virtual line VL1 obtained by extending downward the outer end on one side in the vehicle body width direction of the grip 30a of the steering wheel 30. The second control device 60B overlaps with a virtual line VL2 obtained by extending downward the outer end on the other side in the vehicle body width direction of the grip 30a of the steering wheel 30.

[0092] The second control device 60B is disposed below the first control device 60A. Further, the second control device 60B is disposed below the steering motor 38. That is, the second control device 60B is disposed at a position shifted downward with respect to the first control device 60A and the steering motor 38. Thereby, it is possible to prevent the second control device 60B from being adversely affected by heat generated from the first control device 60A or the steering motor 38.

[0093] As shown in FIG. 10, the second control device 60B and the steering motor 38 are disposed to the right with respect to the axis CL1 of the steering shaft 31. In this way, since the second control device 60B and the steering motor 38 are disposed in the same direction (rightward) in the vehicle body width direction, the second control device 60B is located in the vicinity of the steering motor 38. Thereby, the harness for electrically connecting the second control device 60B and the steering motor 38 can be shortened, and the second control device 60B is less likely to be affected by noise.

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

[0095] That is, as shown in FIG. 16, the holding member 96 (first holding portion 96a) supports the first control device 60A on one side (left side) of the steering shaft 31 and the gear case 39a in a plan view. The holding member 96 (second holding portion 96b) supports the second control device 60B on one side (left side) of the steering shaft 31 and the gear case 39a in a plan view. Further, the holding member 96 (second holding portion 96b) supports the second control device 60B so that the second control device 60B shifts to one side (left side) as it goes from the front end to the rear end. Thereby, since the space 200A between the connector side (front side) of the gear case 39a and the second control device 60B can be widened, wiring and the like can be easily performed.

[0096] Also, as shown in FIG. 10, when the holding member 96 views the first control device 60A and the second control device 60B with respect to the gear case 39a as a reference, 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 middle portion in the vehicle body width direction of the connecting portion 96c of the holding member 96 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 FIG. 15, the connecting member 97 extends forward and backward from the connecting portion 96c, respectively. The rear end portion of the connecting member 97 is fixed to the upper portion of the support post 85. The front end portion of the connecting member 97 is connected to the rear end portion of a stay 98 that extends in the front-rear direction.

[0097] Specifically, as shown in FIGS. 16 and 17, the connecting member 97 is composed of a plate member, and has a front plate portion 97a to which the 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 (toward the steering shaft 31) from the connecting portion 96c, one plate portion 97c that extends from the rear plate portion 97b toward the first control device 60A side, and the other plate portion 97d that extends from the rear plate portion 97B toward the second control device 60B side. The one plate portion 97c and the other plate portion 97d are integrally formed and are inclined downward as they go toward the steering shaft 31. The rear ends of the one plate portion 97c and the other plate portion 97d are attached to the support post 85.

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

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

[0100] As shown in FIGS. 28 and 29, receiving device 41 is attached to lops 61. Before explaining the attachment position of receiving device 41, the specific configuration of lops 61 will be described. The roll bar 61 is provided behind the driver's seat 10. The roll bar 61 has a first vertical column portion 61a, a second vertical column portion 61b, and a cross member portion 61c. The first vertical column portion 61a, the second vertical column portion 61b, and the cross member portion 61c are integrally formed by bending a square pipe. The first vertical column portion 61a extends vertically on the left and rear side of the driver's seat 10. The second vertical column portion 61b extends vertically on the right and rear side of the driver's seat 10. The cross member portion 61c extends in the vehicle width direction and connects the upper end of the first vertical column portion 61a and the upper end of the second vertical column portion 61b above and behind the driver's seat 10. As a result, the roll bar 61 is formed in a substantially gate shape as viewed from the front as a whole. The roll bar 61 can be swung backward with the pivot shafts 102 provided at the lower ends of the first vertical column portion 61a and the second vertical column portion 61b as fulcrums.

[0101] The receiving device 41 is attached to the cross member portion 61c of the roll bar 61. The receiving device 41 is fixed to a bracket 103, and the bracket 103 is attached to the cross member portion 61c. The bracket 103 is attached to the central portion of the cross member portion 61c in the vehicle width direction and extends rearward from the central portion. As a result, the receiving device 41 is located behind the central portion of the cross member portion 61c in the vehicle width direction. In this way, the receiving device 41 is arranged at a position offset (shifted) rearward from the roll bar 61. Further, the receiving device 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 FIGS. 28 and 29. For example, the receiving device 41 may be arranged at a position offset forward or laterally from the roll bar 61. Further, the receiving device 41 may be attached to the first vertical column portion 61a or the second vertical column portion 61b of the roll bar 61, or may be attached to a location other than the roll bar 61 of the tractor 1. Further, instead of the roll bar 61, a canopy may be used, and the receiving device 41 may be attached to the canopy. <Arrangement of Inertial Measurement Device, etc.> Next, the arrangement of the inertial measurement device 42 that constitutes the position detection device 40 and the like will be described.

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

[0104] Further, the inertial measurement device 42 is disposed above the transmission case 74. In other words, the inertial measurement device 42 is disposed at a position that overlaps with the transmission case 74 in a plan view. Since the inertial measurement device 39 is at a position that overlaps with the transmission case 10, the position of the inertial measurement device 39 is close to the center of gravity position of the vehicle body 3. Therefore, it becomes easier for the inertial measurement device 39 to measure a representative value of the attitude change of the vehicle body 3 (a value that can represent the attitude change in the vehicle body 3), and the position of the vehicle body 3 can be quickly and accurately obtained following the attitude change of the vehicle body 3. In other words, since the inertial measurement device 39 is disposed at a position where the weight balance in the front-rear, left-right, and height directions in the vehicle body 3 is good, the measurement accuracy of the position of the vehicle body 3 can be improved.

[0105] Further, as shown in FIG. 20, the inertial measurement device 42 is disposed on the axis CL3 of the rear axle in a plan view. When a working device (implement) is attached to the connecting portion 8, the center of gravity position of the vehicle body 2 and the working device is closer to the axis CL3 of the rear axle than the center in the front-rear direction of the vehicle body 2. Therefore, since the inertial measurement device 42 is disposed on the axis CL3 of the rear axle, even when a working device (implement) is attached to the connecting portion 8, the inertial measurement device 39 is close to the center of gravity position of the vehicle body 3, so that the position of the vehicle body 3 can be quickly and accurately obtained.

[0106] Hereinafter, mainly based on FIGS. 19 to 25, the support structure (mounting structure) of the inertial measurement device 42 will be described. The inertial measurement device 42 is supported by the support member 65 on the vehicle body 3 (transmission case 74) via the vibration isolation member 64. The vibration isolation member 64 is a member that suppresses the vibration of the inertial measurement device 42 and is, for example, an elastically deformable member such as rubber or a spring.

[0107] The support member 65 supports the inertial measurement device 42 on the vehicle body 3 via the vibration isolation member 64. More specifically, the support member 65 supports the inertial measurement device 42 on a housing that covers a drive unit that drives the vehicle body 3 via the vibration isolation member 64. The drive unit is a prime mover 4 or a device that transmits the power of the prime mover 4. In the case of this embodiment, the drive unit is the transmission 5 and the housing is the transmission case 74. However, the housing on which the support member 65 is supported is not limited to the transmission case 74, and the drive unit covered by the housing is not limited to the transmission 5. For example, the housing may be the clutch housing 72 and the drive unit may be a clutch. Hereinafter, the description will be made on the assumption that the drive unit is the transmission 5 and the housing is the 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. That is, the support member 65 is indirectly attached to the transmission case 74 via the support plate 66. However, the support member 65 may be directly attached to the transmission case (housing) 74 (without passing through the support plate 66). The support plate 66 is disposed below the driver's seat 10 and supports the driver's seat 10 from below. A support bracket 100 and a cushioning material 101 are attached to the upper surface of the support plate 66. The support bracket 100 is fixed to the left front portion and the right front portion of the support plate 66 by welding or the like respectively, and extends forward from the support plate 66. In the case of the present embodiment, the support bracket 100 is composed of an angle material having an L-shaped cross section. The cushioning material 101 is composed of an elastic material such as rubber. In the case of the present embodiment, the cushioning material 101 is cylindrical. The cushioning material 101 is fixed to the left rear portion and the right rear portion 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 the upper portions of the support bracket 100 and the cushioning material 101.

[0109] The support plate 66 is attached to the upper portion of the transmission case 74. As shown in FIGS. 19, 22, etc., the transmission case 74 has a protruding portion 74a that protrudes upward from the upper surface of the transmission case 74. The protruding portion 74a includes a front protruding portion 74a1 that protrudes upward from the front portion of the transmission case 74 and a rear protruding portion 74a2 that protrudes upward from the rear portion of the transmission case 74. The front protruding portion 74a1 and the rear protruding portion 74a2 are arranged at intervals in the front-rear direction and extend in the vehicle width direction respectively. Thread holes 74b that extend in the vertical direction are formed in the front protruding portion 74a1 and the rear protruding portion 74a2 respectively. A plurality of the thread holes 74b are formed at intervals in the vehicle width direction for each of the front protruding portion 74a1 and the rear protruding portion 74a2. In the case of the present embodiment, two thread holes 74b (a total of four) are formed in the front protruding portion 74a1 and the rear protruding portion 74a2 respectively.

[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 FIGS. 19, 21, and 22, the first through-hole 66a is formed at 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 at the left front part and the right front part of the support plate 66, respectively. The rear through-hole 66a2 is formed at the left rear part and the right rear part of the support plate 66, respectively. A bolt B1 is inserted into the first through-hole 66a, and by screwing the bolt B1 into the screw hole 74b, the support plate 66 is fixed to the upper part of the transmission case 74.

[0111] As described above, the transmission case 74 is integrally connected to the front axle frame 70, the flywheel housing 71, the clutch housing 72, and the intermediate frame 73 to form a highly rigid vehicle body frame. Therefore, the support plate 66 is fixed to the highly rigid vehicle body 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 FIGS. 21 and 24, the second through-hole 66b is provided at a position closer to the rear of the support plate 66. More specifically, the second through-hole 66b is provided behind the front through-hole 66a1 and in front of the rear through-hole 66a2. The second through-hole 66b includes a one-side through-hole 66b1 provided on one side (left side) in the vehicle body width direction and the other-side through-hole 66b2 provided on the other side (right side) in the vehicle body width direction. The one-side through-hole 66b1 and the other-side through-hole 66b2 are provided at symmetric positions with the center line CL2 in the vehicle body width direction interposed therebetween.

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

[0113] As shown in FIGS. 21, 24, etc., 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 (such as a metal plate). The mounting portion 65a is disposed below the support plate 66. The mounting portion 65a is in a flat plate shape and is disposed parallel to the support plate 66. An inertial measurement device 42 is attached to the mounting portion 65a. Specifically, the inertial measurement device 42 is placed on the upper surface of the mounting portion 65a and is fixed to the upper surface by fixtures (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 rising portion 62 rising from the left end of the mounting portion 65a and a first upper plate portion 67 extending leftward from the upper end of the first rising portion 62. The second fixing portion 65b2 has a second rising portion 63 rising from the right end of the mounting portion 65a and a second upper plate portion 68 extending rightward from the upper end of the second rising portion 63. The upper surface of the first upper plate portion 67 and the upper surface of the second upper plate portion 68 are disposed at the same height and are disposed parallel to the upper surface of the mounting portion 65a.

[0115] As shown in FIGS. 24 and 25, a first mounting hole 67a is formed in the first upper plate portion 67. A second mounting hole 68a is formed in the second upper plate portion 68. The first mounting hole 67a and the second mounting hole 68a are through holes extending in the vertical direction. The first mounting hole 67a is disposed at a position overlapping with one through hole 66b1. The second mounting hole 68a is disposed at a position overlapping with the other through hole 66b2. Bolts B3 are inserted into the first mounting hole 67a and the second mounting hole 68a, respectively. The bolt B3 inserted into the first mounting hole 67a passes through the one through hole 66b1 and is screwed into the screw hole of the first female screw member 691. The bolt B3 inserted into the second mounting hole 68a passes through the other through hole 66b2 and is screwed into the screw hole of the second female screw member 692. Thereby, the fixing portion 65b is fixed to the support plate 66 by the bolt B3.

[0116] As shown in FIGS. 24, 25, etc., the fixing portion 65b (the first fixing portion 65b1, the second fixing portion 65b2) is fixed to the support plate 66 via the vibration-proof member 64. The vibration-proof member 64 is composed of an elastic body (such as rubber) having a substantially cylindrical shape. As shown in FIG. 25, the vibration-proof member 64 has a first large-diameter portion 64a, a second large-diameter portion 64b, and a small-diameter portion 64c. The first large-diameter portion 64a is provided at the upper portion of the vibration-proof member 64. The second large-diameter portion 64b is provided at the lower portion of the vibration-proof member 64. The small-diameter portion 64c is provided between the first large-diameter portion 64a and the second large-diameter portion 64b. Although FIG. 25 shows the mounting structure of the vibration-proof member 64 in the first fixing portion 65b1, the mounting structure of the vibration-proof member 64 in the second fixing portion 65b2 is the same.

[0117] The first large-diameter portion 64a is interposed between the upper surface of the fixing portion 65b (the first fixing portion 65b1 and the 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 (the first fixing portion 65b1 and the second fixing portion 65b2) and the head of the bolt B3. The small-diameter portion 64c is interposed between the outer peripheral surface of the bolt B3 and the inner peripheral surface of the mounting holes (the first mounting hole 67a and the second mounting hole 68a) of the support member 65. In this way, the vibration-proof member 64 is interposed between the bolt B3 and the fixing portion 65b (the first fixing portion 65b1 and the second fixing portion 65b2), and between the fixing portion 65b (the first fixing portion 65b1 and the 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-proof member 64 caused by the tightening of the bolt B3, or may be formed in a state where the vibration-proof member 64 is not elastically deformed. As described above, the support member 65 supports the inertial measurement device 42 below the support plate 66 via the vibration-proof member 64.

[0119] As shown in FIGS. 20, 21, etc., the support plate 66 has an opening 66c provided above the inertial measurement device 42. The inertial measurement device 42 is exposed from the opening 66c. That is, the inertial measurement device 42 has a portion located below the support plate 66 and a portion protruding above the support plate 66 through the opening 66c. The uppermost surface of the inertial measurement device 42 is located above the support plate 66, but is separated from the lower surface of the driver's seat 10 by a distance that can surely avoid contact with the lower surface. Also, the opening 66c exposes the fixture (nut N1). Thereby, it is possible to easily remove the fixture by inserting a hand, a tool, etc. from the opening 66c. Also, by protruding the upper part of the inertial measurement device 42 from the opening 66c, the occupied space in the thickness direction (vertical direction) of the inertial measurement device 42 can be reduced.

[0120] Furthermore, the attachment position of the inertial measurement device 42 is not limited to the above-described embodiment. From the viewpoint of accurately detecting the behavior of the tractor (work vehicle) 1 by the inertial measurement device 42, mainly four positions are conceivable as the position where the inertial measurement device 42 is attached. The first position is within the region connecting the left front wheel 7FL, the right front wheel 7FR, the left rear wheel 7RL, and the right rear wheel 7RR, and is indicated by reference sign A in FIG. 26. The second position is within the vicinity of 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 reference sign B in FIG. 26. The third position is near the center of gravity position of the tractor 1. The fourth position is the range in which the zero moment point (ZMP) moves when the tractor 1 is traveling (the range in which the center of gravity position moves during traveling (dynamic center of gravity position)), and is indicated by reference sign C in FIG. 26. The range in which the ZMP indicated by reference sign C in FIG. 26 moves is a stable region (for example, a region in which the vehicle travels stably) where the posture of the tractor 1 is stable during traveling.

[0121] The calculation of the ZMP can be performed by providing a plurality of vehicle state detection units on the vehicle body 3. The vehicle state detection unit is a device that detects at least the first load (floor reaction force) and moment applied to the vehicle body 3. For example, a six-axis force type load cell capable of detecting the first load and moment in the three-axis directions (X-axis direction, Y-axis direction, Z-axis direction) is used. The X-axis direction can be set as the traveling direction of the vehicle body 3, the Y-axis direction as the vehicle width direction, and the Z-axis direction as the vertical direction.

[0122] The plurality of vehicle state detection units can include a first state detection unit corresponding to the support point (left front wheel) at the left front part of the vehicle body 3, a second state detection unit corresponding to the support point (right front wheel) at the right front part of the vehicle body 3, a third state detection unit corresponding to the support point (left rear wheel) at the left rear part of the vehicle body 3, and a fourth state detection unit corresponding to the support point (right rear wheel) at the right rear part of the vehicle body 3. The calculation of the ZMP can be performed by a control device (control device 60 or other control device) (computer). The control device obtains the ZMP represented in two dimensions based on the first load (floor reaction force) of the support points of the vehicle body 3, for example, the floor reaction force and moment in the first state detection unit, the second state detection unit, the third state detection unit, and the fourth state detection unit.

[0123] In FIG. 26, the region Q1 connecting the support points (the positions where a plurality of vehicle state detection units are installed) of the vehicle body 3 is a critical region, which is represented two-dimensionally by the X-axis and the Y-axis. The stable region Q2(C) is a stable region where the posture of the tractor 1 is stable during traveling, 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 line constituting the critical region Q1 and the contour line constituting the stable region Q2 is an unstable region Q3 that is likely to become unstable.

[0124] By setting the mounting position of the inertial measurement device 42 to the stable region Q2(C), the measurement accuracy of the inertial measurement device 42 can be improved. <Effect> According to the work vehicle (tractor) 1 of the above embodiment, the following effects can be obtained. 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 travel by either manual steering by the steering wheel or automatic steering of the steering wheel based on a planned travel line, a setting switch 51 that is disposed around the steering shaft and switches to a setting mode for at least performing settings before the start of automatic steering, and a steering changeover switch 52 that is disposed around the steering shaft and switches the start or end of automatic steering in the setting mode.

[0125] According to this configuration, since the setting switch 51 and the steering changeover switch 52 are disposed around the steering shaft 31, the driver can surely recognize the setting switch 51 and the steering changeover switch 52 at a glance and can easily operate them without changing the posture. Therefore, unintentional automatic steering or the like due to an incorrect operation of the switch can be prevented.

[0126] In addition, the work vehicle 1 includes a position detection device 40 provided on the vehicle body 3 and configured to detect the position of the vehicle body based on signals from positioning satellites, and a correction switch 53 disposed around the steering shaft 31 and configured to correct the position of the vehicle body detected by the position detection device. According to this configuration, in addition to the setting switch 51 and the steering changeover switch 52, the correction switch 53 is also disposed around the steering shaft 31. Therefore, the driver can surely recognize the setting switch 51, the steering changeover switch 52, and the correction switch 53 at a glance and can easily operate them without changing the posture. As a result, it is possible to prevent unintended automatic steering or the like due to an incorrect operation of the switch.

[0127] The work vehicle 1 further includes a display device 45 disposed around the steering shaft 31 and configured to display driving information, and a screen changeover switch 54 disposed around the steering shaft and configured to selectively switch the display of the display device between a first screen G1 that displays the driving status in the setting mode and a second screen Q2 that explains the setting operation in the setting mode. According to this configuration, in addition to the setting switch 51, the steering changeover switch 52, and the correction switch 53, the screen changeover switch 54 is also disposed around the steering shaft 31. Therefore, the driver can surely recognize the setting switch 51, the steering changeover switch 52, the correction switch 53, and the screen changeover switch 54 at a glance and can easily operate them without changing the posture. As a result, it is possible to prevent unintended automatic steering or the like due to an incorrect operation of the switch.

[0128] The setting switch 51 is disposed on one side of the steering shaft 31, and the correction switch 53 is disposed on the other side of the steering shaft 53. According to this configuration, since the setting switch 51 and the correction switch 53 are disposed on opposite sides of the steering shaft 31 with the steering shaft 31 interposed therebetween, the space around the steering shaft 31 can be effectively utilized, and it is possible to prevent incorrect operations of the setting switch 51 and the correction switch 53.

[0129] Further, the steering changeover switch 52 is disposed on one side of the steering shaft 31. According to this configuration, since the steering changeover switch 52 and the setting switch 51 are disposed on the same side with respect to the steering shaft 31, the operability of the switch operation for automatic steering of the work vehicle 1 is improved.

[0130] Also, the setting switch 51 is disposed on one side of the steering shaft 31, and the screen changeover switch 54 is disposed on the other side of the steering shaft 31. According to this configuration, since the setting switch 51 and the screen changeover switch 54 are disposed in opposite directions with the steering shaft 31 therebetween, the space around the steering shaft 31 can be effectively utilized, and the setting switch 51 and the screen changeover switch 54 can be prevented from being erroneously operated.

[0131] Also, a panel cover 78 that supports the display device 45 is provided below the steering wheel 30, and the setting switch 51, the correction switch 53, and the screen changeover switch 54 are provided on the panel cover. According to this configuration, the setting switch 51, the correction switch 53, and the screen changeover switch 54 are intensively arranged on the panel cover 78 that supports the display device 45. Therefore, the driver can visually recognize the setting switch 51, the correction switch 53, and the screen changeover switch 54 together with the display device 45, and the operability is improved. Also, since the setting switch 51, the correction switch 53, and the screen changeover switch 54 are disposed at positions separated from the steering wheel 30, it is possible to prevent unintentionally contacting the setting switch 51, the correction switch 53, and the screen changeover switch 54 during the operation of the steering wheel 30, or unintentionally contacting the steering wheel 30 during the operation of the setting switch 51, the correction switch 53, and the screen changeover switch 54. Therefore, it is possible to prevent an unintended switching to automatic steering due to an erroneous operation.

[0132] In addition, the work vehicle 1 includes a connecting portion 8 provided at the rear of the vehicle body 3 for connecting the working device, and a lifting lever 83 for lifting and lowering the connecting portion 8. The lifting lever is disposed on the other lateral side of the steering shaft 31. According to this configuration, since the lifting lever 83 and the steering changeover switch 52 are disposed in opposite directions with the steering shaft 31 therebetween, the space around the steering shaft 31 can be effectively utilized. Further, it is possible to prevent an unintended operation by the driver from being performed by contacting the steering changeover switch 52 during the operation of the lifting lever 83 or contacting the lifting lever 83 during the operation of the steering changeover switch 52.

[0133] In addition, the setting switch 51 and the correction switch 53 are disposed behind the steering shaft 31. According to this configuration, since the setting switch 51 and the correction switch 53 are disposed on the driver side for operating the steering wheel 30, the operability of the setting switch 51 and the correction switch 53 is improved, and it is less likely to cause an erroneous operation.

[0134] The work vehicle 1 further includes a steering wheel 30, a steering shaft 31 that rotatably supports the steering wheel 30, a vehicle body 3 that can travel by either manual steering by the steering wheel or automatic steering of the steering wheel based on a planned travel line, a position detection device 40 provided on the vehicle body and configured to detect the position of the vehicle body based on a signal from a positioning satellite, 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 disposed on one lateral side of the steering shaft and configured to output a control signal calculated based on the position of the vehicle body detected by the position detection device, and a second control device 60B disposed on the other lateral side of the steering shaft and configured to control the automatic steering mechanism so that the vehicle body travels along the planned travel line based on the control signal output by the first control device.

[0135] According to this configuration, compared with the case where the first control device 60A and the second control device 60B are integrated into one control device, the control device is downsized. Therefore, the control device (the first control device 60A and the second control device 60B) can be arranged in a small space near the steering shaft 31. Further, since the first control device 60A and the second control device 60B are arranged in opposite directions with the steering shaft 31 therebetween, it is possible to prevent the other control device from being adversely affected by the heat generated from one control device.

[0136] Further, the work vehicle 1 includes a display device 45 that is arranged around the steering shaft 31 and displays driving information, and a panel cover 78 that supports the display device below the steering wheel 30. The first control device 60A and the second control device 60B are arranged within the panel cover 78. According to this configuration, since the first control device 60A and the second control device 60B are arranged within the panel cover 78 while being arranged near the steering shaft 41, the panel cover 78 can be made smaller. Therefore, it is possible to sufficiently secure the foot space and the forward visibility of the driver.

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

[0138] According to this configuration, since the power steering device 32 and the automatic steering mechanism 37 are arranged at separated positions, the operations of the power steering device 32 and the automatic steering mechanism 37 can be made independent of each other, and the power steering device 32 can be operated regardless of the operation or non-operation of the automatic steering mechanism 37. Further, the work vehicle 1 includes a display device 45 that is arranged around the steering shaft 31 and displays operation information, a panel cover 78 that supports the display device below the steering wheel, and front wheels 7F and rear wheels 7R that support the vehicle body 3 so as to be capable of traveling. The vehicle body has a front axle frame 72 that supports the front wheels. The automatic steering mechanism is arranged within the panel cover, and the power steering device includes a hydraulic pump 33, a control valve 34 to which the hydraulic oil discharged from the hydraulic pump is supplied, and a steering cylinder 35 that is operated by the control valve. The control valve is supported by the front axle frame 72.

[0139] According to this configuration, the automatic steering mechanism 37 can be arranged within the panel cover 78 in the vicinity of the steering shaft 31 without increasing the size of the panel cover 78. Therefore, sufficient space can be secured for the driver's foot area and the forward visibility. The work vehicle 1 further includes a steering wheel 30, a steering shaft 31 that rotatably supports the steering wheel, a vehicle body 3 that can travel by either manual steering by the steering wheel or automatic steering of the steering wheel based on a planned travel line, and a steering changeover switch 52 that is arranged around the steering shaft and is swingable about a base end portion provided on the steering shaft side as a fulcrum, in a first direction for switching the start or end of automatic steering and in a second direction for setting the start point and the end point of a travel reference line that serves as a reference for the planned travel line.

[0140] According to this configuration, by simply changing the swinging direction of the steering changeover switch 52, it is possible to switch the start or end of the automatic steering and to set the start point and the end point of the travel reference line that serves as the reference for the planned travel line, so the operability is excellent. In addition, compared with the case where a plurality of switches are provided as the steering changeover switch 52, the installation space of the steering changeover switch 52 can be reduced.

[0141] Further, the steering changeover switch 52 swings in the first direction upward or downward, and swings in the second direction forward or backward. According to this configuration, by swinging the steering changeover switch 52 upward, downward, forward, or backward, it is possible to switch the start or end of the automatic steering and to set the start point and the end point of the travel reference line that serves as the reference for the planned travel line, so the operability is excellent.

[0142] Further, the steering changeover switch 52 commands the start of the automatic steering by swinging downward, commands the end of the automatic steering by swinging upward, sets the start point of the travel reference line by swinging backward, and sets the end point of the travel reference line by swinging forward. According to this configuration, each operation of starting the automatic steering, ending the automatic steering, setting the start point of the travel reference line, and setting the end point of the travel reference line can be easily and surely performed.

[0143] In addition, a setting switch 51 is provided that is arranged around the steering shaft 31 and switches to a setting mode for performing at least the setting before starting the automatic steering. According to this configuration, in addition to the steering changeover switch 52, the setting switch 51 is arranged around the steering shaft 31, so that while having various switches, the arrangement space of the switches can be reduced.

[0144] In addition, a position detection device 40 that detects the position of the vehicle body based on the signal of the positioning satellite, and a correction switch 53 that is arranged around the steering shaft 31 and corrects the position detected by the position detection device 40 are provided. According to this configuration, the steering changeover switch 52, the setting switch 51, and the correction switch 53 are collectively arranged around the steering shaft 31, so that while various switches are provided, the space for arranging the switches can be reduced.

[0145] In addition, a screen changeover switch 54 is provided, which is arranged around the steering shaft 31 and selectively switches the display of the display device 45 between a first screen Q1 for displaying the driving status in the setting mode and a second screen Q2 for explaining the setting operation in the setting mode. According to this configuration, in addition to the steering changeover switch 52, the setting switch 51, and the correction switch 53, the screen changeover switch 54 is also collectively arranged around the steering shaft 31. Therefore, while various switches are provided, the space for arranging the switches can be reduced.

[0146] The work vehicle 1 includes a vehicle body 3 that can travel either by manual steering with the steering wheel 30 or by automatic steering of the steering wheel based on a planned travel line, a receiving device 41 provided on the vehicle body for receiving signals from positioning satellites, an inertial measurement device 42 for measuring the inertia of the vehicle body, an automatic steering mechanism 37 for automatically steering the steering wheel based on the signals received by the receiving device and the inertia measured by the inertial measurement device, a vibration damping member 64 for suppressing the vibration of the inertial measurement device, and a support member 65 for supporting the inertial measurement device on the vehicle body via the vibration damping member.

[0147] According to this configuration, the vibration damping member 64 suppresses the transmission of vibrations from the vehicle body 3 and the like to the inertial measurement device 42. Therefore, the measurement error of the inertial measurement device 42 can be reduced, and accurate automatic steering can be performed. In addition, a drive unit (for example, a transmission 5) for driving the vehicle body and a housing (for example, a transmission case 74) for covering the drive unit are provided, and the support member 65 supports the inertial measurement device 42 on the housing via the vibration damping member 64.

[0148] According to this configuration, vibration caused by the driving of the driving unit is suppressed from being transmitted to the inertial measurement unit 42 by the vibration isolation member 64. Therefore, the measurement error of the inertial measurement unit 42 can be reduced. Further, a support plate 66 attached to the housing 74 is provided, and the support member 65 has a mounting portion 65a disposed below the support plate 66 and to which the inertial measurement unit 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 isolation member 64.

[0149] According to this configuration, the inertial measurement unit 42 can be attached in a form of being suspended below the support plate 66 attached to the housing 74 with the vibration isolation member 64 interposed therebetween and the support plate 65. Therefore, vibration can be effectively prevented from being transmitted to the inertial measurement unit 42 by the vibration isolation member 64. In addition, an installation space such as a driver's seat can be secured above the support plate 66.

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

[0151] Further, the fixing portion 65b is fixed to the support plate 66 by a bolt B3, and the vibration isolation member 64 is interposed between the bolt and the fixing portion and between the fixing portion and the support plate. According to this configuration, vibration of the support plate 66 can be reliably prevented from being transmitted to the inertial measurement unit 42 via the support member 65 by the vibration isolation member 64. Further, the housing is the transmission case 74, and the support plate 66 is attached to the upper portion of the transmission case.

[0152] According to this configuration, since the support plate 66 is attached to a highly rigid mission case, the vibration of the support plate 66 to which the support member 65 is fixed is suppressed, and the measurement accuracy of the inertial measurement device 42 can be improved. Further, the support plate 66 has an opening 66c provided above the inertial measurement device 42, and the inertial measurement device is exposed from the opening.

[0153] According to this configuration, the attachment and detachment of the inertial measurement device 42 can be easily performed using the opening 66c. Further, by protruding the upper part of the inertial measurement device 42 from the opening 66c, the occupied space in the thickness direction (vertical direction) of the inertial measurement device 42 can be reduced. As described above, although one embodiment of the present invention has been described, it should be considered that the embodiments disclosed this time are illustrative in all respects and not restrictive. The scope of the present invention is shown not by the above description but by the claims, and it is intended that all modifications within the meaning and scope equivalent to the claims are included.

Explanation of Reference Numerals

[0154] 1 Work vehicle (tractor) 3 Vehicle body 30 Steering wheel 31 Steering shaft 37 Automatic steering mechanism 38 Steering motor 39 Gear mechanism 390 Connecting shaft 391 First gear (gear) 392 Second gear (gear) 393 Third gear (gear) 394 Fourth gear (gear) 45 Display device 52 Steering changeover switch 60B Second control device (control device) 78 Panel cover

Claims

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

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

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

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

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

6. The tractor according to any one of claims 1 to 5, wherein the steering motor, the gear mechanism, and the control device are arranged side by side along the axial direction of the steering shaft in a side view.

7. The tractor according to claim 6 , wherein the control device is disposed on an opposite side to the steering motor across the gear mechanism in a side view in an axial direction of the steering shaft.

8. A display device capable of displaying driving information of a tractor; A panel cover that supports the display device; Equipped with The tractor according to any one of claims 1 to 7, wherein the steering motor, the gear mechanism and the control device are disposed inside the panel cover.

9. The control device has a housing and a circuit board disposed within the housing, The tractor according to claim 8 , wherein the housing is a rectangular parallelepiped and is arranged vertically inside the panel cover with the shortest side facing in the vehicle body width direction or substantially in the vehicle body width direction.

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