JP5080854B2 - Work vehicle - Google Patents

Description

  The present invention relates to a work vehicle configured to be capable of automatically turning a traveling vehicle body at a predetermined turning target angle by steering a front wheel.

  As a conventional technique, for example, as disclosed in Patent Document 1, the turning operation of the front traveling wheel is performed by tilting the turning lever (63 in FIG. 1 of Patent Document 1) to the left or right. A mobile farm machine equipped with a headland controller (75 in FIG. 1 of Patent Document 1) that is automatically operated, or operating a steering handle (26 in FIG. 10 of Patent Document 2) as disclosed in Patent Document 2 Then, the agricultural tractor comprised so that a front wheel may be steered automatically is known.

Japanese Patent No. 3632779 (see FIGS. 1, 2, 5, 8 and paragraph “0022”) Japanese Patent Laying-Open No. 2005-13243 (see FIG. 10 and paragraph number “0041”)

  In the mobile agricultural machine of Patent Document 1, when the turning lever is tilted to the left or right, the front traveling wheel automatically turns to start the automatic turning of the mobile agricultural machine, and when the turning angle turns, the automatic turning of the mobile agricultural machine. Seems to have ended. Further, in the agricultural tractor of Patent Document 2, when the steering handle is operated, the front wheels are automatically steered, and when turning 180 degrees, the turning of the agricultural tractor is completed.

  Therefore, after moving the automatic turn, when moving the moving agricultural machine or the agricultural tractor (hereinafter referred to as adjacent plowing) in accordance with the field adjacent to the field that has already been plowed (hereinafter referred to as adjacent plowing), for example, the machine body Differences in conditions (eg, tiller width, wheelbase length, tread width, type of tiller, etc.) and field work conditions (eg, field hardness, field unevenness, etc.) When the position where the mobile agricultural machine or agricultural tractor has finished turning is far from the adjacent plowing, many operations such as a steering handle are required for the adjacent plowing after the automatic turning. As a result, there is room for improvement in order to improve the workability of adjacent plowing and the workability of tillage work.

Specifically, for example, the case where the turning radius is the same and the width of the tilling device is different will be described as an example. In the case of a narrow tilling device (for example, F in FIG. 10 (a)), the width for tilling the field is small. Since it becomes narrower, by increasing the turning target angle for turning automatically (the angle at which the work vehicle turns between the start of automatic turning and the end of automatic turning) (for example, about 200 degrees in FIG. 10 (a)). ), The work vehicle can be moved to a position close to the adjacent tillage. On the other hand, in the case of a wide tillage device (for example, F in FIG. 10 (b)), the width for tilling the field is widened, so by reducing the turning target angle for automatic turning (for example, FIG. 10 (b)). In this case, the work vehicle can be moved to a position close to the adjacent tillage. Therefore, if the turning target angle is set to be the same when the width of the tilling device is narrow and when the width of the tilling device is wide, the automatic turning may end at a position far from the adjacent tilling. In some cases, it was necessary to operate the steering wheel for adjacent plowing after completion.
An object of this invention is to implement | achieve the work vehicle which can improve the workability | operativity of adjacent tilling and can improve the workability | operativity of tillage work.

[I]
(Constitution)
The first feature of the present invention is to configure the work vehicle as follows.
A direction sensor for detecting the direction of the traveling vehicle body, a turning command input unit for inputting a right or left turning command to the traveling vehicle body,
When a turning command is input by the turning command input unit, the steering wheel is steered to the right or left input by the turning command input unit based on the detection result of the direction sensor, and a preset automatic operation is performed. Automatic turning control means for automatically turning the traveling vehicle body to a turning target angle that is an angle at which the work vehicle turns between the start of turning and the end of automatic turning;
A turning target angle adjuster capable of changing and adjusting the turning target angle in the automatic turning control by the automatic turning control means .

(Function)
According to the first feature of the present invention, for example, the machine condition (for example, the width of the tillage device, the length of the wheel base, the width of the tread, the type of the tillage device, etc.) and the working condition (for example, the hardness of the field, the field) The turning target angle at which the work vehicle is automatically turned can be changed in accordance with the size of the unevenness, etc., and the position of the work vehicle after the completion of the automatic turning can be changed in accordance with the adjacent tillage. As a result, the position at which the work vehicle finishes turning can be positioned close to the adjacent tillage, and the adjacent tilling after the end of automatic turning can be performed with a small number of steering handles or the like.

(Effect of the invention)
According to the 1st characteristic of this invention, the workability | operativity of adjacent plowing can be improved and the workability | operativity of tillage work can be improved.

[II]
(Constitution)
The second feature of the present invention is that the work vehicle of the first feature of the present invention is configured as follows.
When the automatic turning of the traveling vehicle body by the automatic turning control means is completed, there is provided a front wheel automatic operation means for automatically operating the front wheel in the straight traveling direction side of the traveling vehicle body or in the reverse direction side beyond the straight traveling direction.

(Function)
According to the second feature of the present invention, the “action” described in the preceding item [I] is provided in the same manner as the first feature of the present invention, and in addition to this, the following “action” is provided.
According to the second feature of the present invention, when the turning of the traveling vehicle body by the automatic turning control means is completed, the front wheels are automatically automatically operated to the straight direction side of the traveling vehicle body or the reverse direction side beyond the straight traveling direction, and the turning is completed. The direction of the rear front wheel can be made closer to the direction of adjacent plowing. As a result, for example, compared to the case where the turning of the traveling vehicle body is finished while the direction of the front wheel after the completion of the automatic turning has been steered in the turning direction at the time of turning, the front wheel moves straight ahead of the traveling vehicle body after the completion of the turning. The steering wheel can be operated in the direction opposite to the direction side or in the reverse direction beyond the straight direction, and the steering operation can be reduced, and the adjacent tilling after the automatic turning can be performed with a small number of steering handles.

(Effect of the invention)
According to the second feature of the present invention, the “effect of the invention” described in the preceding item [I] is provided in the same manner as the first feature of the present invention. In addition, the following “effect of the invention” is provided. ing.
According to the 2nd characteristic of this invention, the workability | operativity of adjacent plowing can be improved further and the workability | operativity of tillage work can further be improved.

[Overall structure of tractor]
FIG. 1 is an overall left side view of a tractor as an example of a work vehicle. As shown in FIG. 1, an engine 2 is disposed at the front of the traveling vehicle body 1, and a pair of left and right steerable front wheels 3 and a pair of left and right rear wheels 4 are driven by power from the engine 2. Thus, the tractor travels and turns according to the operation of the steering handle 6 of the driver seated on the driver seat 5.

  A pair of left and right lift arms 8 are linked to the rear part of the transmission case 7 disposed at the rear part of the traveling vehicle body 1, and the swing arm 10 is swung up and down by operating the lift cylinder 9. An elevating mechanism is configured so that the tilling device F connected to the rear end of the swing arm 10 can be driven up and down.

  A rearward PTO shaft 11 for taking out the power from the engine 2 is provided at the rear part of the transmission case 7, and the rotary device F1 of the tiller device F can be driven to rotate by interlockingly connecting the tiller device F to the PTO shaft 11. It is configured.

  As shown in FIG. 2, the steering device 12 includes a power cylinder 13, an operation valve 14, a main pump 16, and a metering pump 18. A different configuration may be adopted as the steering device 12, not the hydraulic steering device 12 using the main pump 16, the power cylinder 13, or the like, but the steering device 12 that does not include the power cylinder 13, or other than the power cylinder 13. You may employ | adopt the steering device 12 provided with the actuator.

  The power cylinder 13 is linked to the knuckle arms 3a of the left and right front wheels 3, and a main pump 16 linked to the engine 2 is connected to an operation valve 14 of the power cylinder 13 via a hydraulic circuit 15. Yes. A metering pump 18 is connected to the operation valve 14 via a hydraulic circuit 17, and an input shaft 18 a of the metering pump 18 is linked to the steering handle 6 via a steering differential mechanism 20 described later. .

[Steering differential mechanism]
As shown in FIG. 2, the steering differential mechanism 20 is constituted by a planetary gear mechanism, and includes a first gear 21 as a sun gear fixed to the input shaft 18 a of the metering pump 18, and a handle of the steering handle 6. The second gear 22 fixed to the operating shaft 6a, the carrier 23 supported on the steering wheel operating shaft 6a of the steering handle 6 so as to be relatively rotatable, and the carrier 23 and the first and second gears 21, 22 A plurality of first and second planetary gears 24 and 25 are provided.

  The input shaft 18a of the metering pump 18 constituting the steering device 12 and the handle operation shaft 6a of the steering handle 6 are disposed concentrically, and a steering differential is provided between the input shaft 18a and the handle operation shaft 6a. A mechanism 20 is provided.

  The carrier 23 is fixed to a first tube shaft 26 that is rotatably supported by the handle operating shaft 6 a of the steering handle 6, and is relative to the support shafts 23 a disposed at a plurality of locations on the outer periphery of the carrier 23. The second cylinder shaft 27 is supported rotatably. A first planetary gear 24 is fixed to the second cylindrical shaft 27, and the first planetary gear 24 is engaged with a first gear 21 fixed to the input shaft 18 a of the metering pump 18.

  A second planetary gear 25 having a smaller number of teeth than the first planetary gear 24 is fixed to the second cylindrical shaft 27, and the second planetary gear 25 is connected to the handle operating shaft 6 a having a larger number of teeth than the first gear 21. It is engaged with the fixed second gear 22. An input gear 28 is fixed to the first cylindrical shaft 26, and this input gear 28 is engaged with an output gear 29 that is fixed to the drive shaft 30 a of the steering motor 30 and has fewer teeth than the input gear 28. Yes.

  As described above, by configuring the steering device 12 and the steering differential mechanism 20, when the steering motor 30 is stopped and the drive shaft 30a is not rotating, the output gear 29 connected to the drive shaft 30a, the first Since the one cylinder shaft 26 and the carrier 23 do not rotate, when the handle operating shaft 6a is rotated by the driver's operation of the steering handle 6, the second gear 22, the second planetary gear 25, the second cylinder shaft 27, the first The input shaft 18 a of the metering pump 18 is configured to rotate according to the operation amount of the steering handle 6 via the planetary gear 24 and the first gear 21.

  Since the first gear 21, the second gear 22, and the first and second planetary gears 24 and 25 are set to have different numbers of teeth, the rotation of the handle operating shaft 6a of the steering handle 6 is accelerated and metered. It is configured to be transmitted to the input shaft 18 a of the ring pump 18.

  On the other hand, when the driver holds the steering handle 6 and the steering operation shaft 6a is not substantially rotated, when the steering motor 30 is rotated forward and backward, the output gear 29 and the input gear connected to the drive shaft 30a of the steering motor 30 are provided. The first cylinder shaft 26 is rotated via 28, the carrier 23 fixed to the first cylinder shaft 26 rotates relative to the handle operating shaft 6 a, and the second cylinder relative to the support shaft 23 a of the carrier 23. The shaft 27 relatively rotates, and the first and second planetary gears 24 and 25 fixed to the second cylindrical shaft 27 rotate. Since the second planetary gear 25 is engaged with the non-rotating second gear 22, when the first and second planetary gears 24, 25 rotate, the first and second gears 21, 22, The input shaft 18a of the metering pump 18 rotates corresponding to the transmission ratio of the second planetary gears 24 and 25.

  The output gear 29 and the input gear 28 are set to have different numbers of teeth, and the input gear 28 is connected to the input shaft 18a of the metering pump 18 via the steering differential mechanism 20, so that the steering motor 30 The rotation of the drive shaft 30a is decelerated by the output gear 29, the input gear 28, and the steering differential mechanism 20, and is transmitted to the input shaft 18a of the metering pump 19.

  The rotational speed of the steering motor 30 can be arbitrarily changed and adjusted. By changing the rotational speed of the steering motor 30 from the control device 31 to be described later via the motor drive circuit 45, the rotational speed of the steering motor 30 is adjusted. Accordingly, the rotational speed of the input shaft 18a of the metering pump 18 can be arbitrarily changed and adjusted.

  Therefore, the input shaft 18a of the metering pump 18 can be rotated by rotating the steering motor 30 forward and backward while holding the steering handle 6 and the handle operating shaft 6a is not rotating, and the left and right front wheels 3 can be operated. Can be operated in the opposite direction.

  When the steering motor 30 is rotated forward so that the first cylinder shaft 26 rotates in the direction opposite to the direction in which the driver rotates the steering handle 6, the input shaft of the metering pump 18 according to the number of rotations of the steering motor 30. As the rotation of 18a is increased, the steering ratio (ratio of the operation amount of the input shaft 18a of the steering device 12 corresponding to the operation amount of the steering handle 6) can be greatly changed.

  On the contrary, when the steering motor 30 is reversed so that the first cylinder shaft 26 rotates in the same direction as the direction in which the driver rotates the steering handle 6, the metering pump 18 of the metering pump 18 is changed according to the rotation speed of the steering motor 30. The rotation of the input shaft 18a is decelerated, and the steering ratio (ratio of the operation amount of the input shaft 18a of the steering device 12 corresponding to the operation amount of the steering handle 6) can be changed small.

  When the steering handle 6 is operated or the steering motor 30 is rotated to rotate the input shaft 18a of the metering pump 18, the operation valve 14 is operated in accordance with the operation amount of the input shaft 18a. 13 is supplied with pressure oil, and the operation of the power cylinder 13 causes the left and right front wheels 3 to operate in the steering direction corresponding to the rotational direction of the steering handle 6 or the steering motor 30 and to operate the input shaft 18a of the metering pump 18. The knuckle arm 3a is swung with a cutting angle corresponding to the amount. Then, the traveling vehicle body 1 is steered so as to travel in the traveling direction corresponding to the operation direction of the steering handle 6 or the steering motor 30 according to the operation amount of the steering handle 6 or the steering motor 30.

[Block diagram of control device and travel transmission system]
3 and 4 show a block diagram of the tractor control device 31 and a schematic plan view of the traveling transmission system of the tractor. As shown in FIGS. 3 and 4, the tractor includes a steering angle sensor 32, a drive shaft rotation sensor 33, an input shaft rotation sensor 34, a lever position detection sensor 36, a turning direction detection sensor 38, and a direction sensor 39 (in the direction sensor). Equivalent), yaw rate sensor 40 (equivalent to direction sensor), lift position detection sensor 41, turning angle adjuster 42 (equivalent to turning target angle adjuster), ascent speed adjuster 43, intermediate position adjuster 44, front wheel break angle sensor 66, detection devices such as a vehicle speed sensor 67 are mounted.

  As shown in FIG. 3, the steering angle sensor 32 is provided on the handle operating shaft 6a of the steering handle 6 (see FIG. 2), and by measuring the rotation angle of the handle operating shaft 6a from the reference position, the left and right steering angles are measured. By calculating the steering angle of the front wheel 3, it is possible to detect the operation amount (steering operation amount) of the steering handle 6 and the operation speed (steering operation speed) of the steering handle 6 of the driver.

  The drive shaft rotation sensor 33 and the input shaft rotation sensor 34 are respectively provided on the drive shaft 30a of the steering motor 30 and the input shaft 18a of the metering pump 18 (see FIG. 2). The rotational speed of the input shaft 18a of the ring pump 18 can be detected.

  The detection results from the steering angle sensor 32, the drive shaft rotation sensor 33, and the input shaft rotation sensor 34 are fed back and output from the motor drive circuit 45 to the steering motor 30, whereby the input shaft 18a of the metering pump 18 is output. , It can be accurately rotated to a predetermined rotational speed. This tractor is equipped with three sensors, a steering angle sensor 32, a drive shaft rotation sensor 33, and an input shaft rotation sensor 34, and is configured to output from the motor drive circuit 45 to the steering motor 30. Any two of the sensors are mounted on the tractor, and the control device 31 performs arithmetic processing based on the detection results from the two sensors so as to output from the motor drive circuit 45 to the steering motor 30. May be.

  A rectilinear lever 35 that allows the traveling vehicle body 1 to travel straight forward is mounted on the side of the steering handle 6 so as to be swingable. The rectilinear lever 35 is neutrally positioned at a neutral position when the rectilinear lever 35 is not operated. It is energized. A lever position detection sensor 36 is provided at the base of the rectilinear lever 35, and the operation position (manually raised position, neutral position, rectilinear position) of the rectilinear lever 35 can be detected. The manual raising position of the straight advance lever 35 is operated when the driver wants to raise the tillage device F manually. For example, when the steering handle 6 is operated to cancel the automatic straight advance control described later. The tillage device F can be raised artificially.

  A turning lever 37 (corresponding to a turning command input unit) is provided on the side of the driver's seat 5, and the turning lever 37 can instruct the turning and turning direction of the traveling vehicle body 1. The swivel lever 37 is neutrally biased to the neutral position N when not operated. A turning direction detection sensor 38 that detects an operation position of the turning lever 37 is provided at the base of the turning lever 37, and the operation position (left direction L, neutral position) of the turning lever 37 is detected by the turning direction detection sensor 38. N and right direction R) can be detected.

  In addition, you may employ | adopt the structure equipped with the operation lever (not shown) which has the function of the rectilinear advance lever 35 and the turning lever 37 and can switch 4 positions. Specifically, for example, the side of the steering handle 6 is equipped with an operation lever that can be swung up and down and back and forth and urged to the center. It may be configured to be operated in the left direction L or the right direction R when operated to the position and swinging the operation lever forward or backward.

  The azimuth sensor 39 is disposed at the left and right center of the traveling vehicle body 1 and detects the traveling direction of the traveling vehicle body 1. The yaw rate sensor 40 is disposed near the center of gravity of the traveling vehicle body 1 and detects the yaw rate acting on the tractor. The swinging part (see FIG. 1) of the lift arm 8 is provided with a lift position detection sensor 41, which is configured to detect the height of the tiller F that is lifted and lowered by the lift cylinder 9.

  The front wheel turning angle sensor 66 is attached to the rotating portion of the knuckle arm 3a linked to the front wheel 3 (see FIG. 2), and detects the turning angle of the front wheel 3 operated by the steering device 12. The vehicle speed sensor 67 is provided in the traveling vehicle body 1 and detects the vehicle speed of the tractor.

  Based on the detection result of the front wheel cutting angle sensor 66, the cutting angle of the front wheel 3 is monitored by the control device 31, and for example, when the cutting angle of the front wheel 3 changes due to leakage of hydraulic oil in the power cylinder 13, etc. The control device 31 corrects the cutting angle of the front wheel 3 based on the detection result of the front wheel cutting angle sensor 66, and the accurate cutting angle of the front wheel 3 is grasped by the control device 31, and the corrected cutting angle of the front wheel 3 will be described later. The automatic straight running control and the automatic turning control are performed.

  Turning on the side of the driver's seat 5 for setting the turning angle (turning target angle: the angle at which the work vehicle turns between the start of automatic turning and the end of automatic turning), which will be described later. An angle adjuster 42, an ascending speed adjuster 43 for setting an ascending speed for automatic turning control, and an intermediate position adjusting tool 44 for setting an intermediate position for automatic turning control are provided. By dialing the speed adjuster 43 or the intermediate position adjuster 44, the turning angle, the rising speed, or the intermediate position in automatic turning control described later can be manually changed and adjusted to a value desired by the driver.

  The control device 31 is connected to a motor drive circuit 45, an electromagnetic valve 46, an electronic governor controller 48, a speed change actuator 51, a front wheel speed change actuator 52, an operation valve 54, a PTO actuator 55, a differential lock actuator 56, a display device 57, and the like. .

  The motor drive circuit 45 is connected to the steering motor 30, and outputs to the motor drive circuit 45 from the control device 31, thereby driving and stopping the steering motor 30 based on the output from the control device 31, and the rotation direction. And the rotation speed can be changed.

  The electromagnetic valve 46 is linked to the lift cylinder 9, and the lifting / lowering operation of the tillage device F by the lift cylinder 9 can be performed by outputting the electromagnetic valve 46 from the control device 31.

  An electronic governor 47 having an actuator (not shown) for changing the rotational speed of the engine 2 is mounted on the engine 2 of the vehicle, and an accelerator sensor 49 for detecting an operation amount of an accelerator pedal (not shown), Based on the detection result from the rotation sensor 50 that detects the rotation speed of the engine 2, the output of the engine 2 is electrically output from the control device 31 to the electronic governor controller 48 connected to the electronic governor 47. It is configured so that it can be controlled. In addition, as long as the rotation speed of the engine 2 can be electrically controlled, not only the electronic governor 47 and the electronic governor controller 48 but other configurations (not shown) may be adopted.

  A tractor travel transmission (not shown) is equipped with a transmission actuator 51, and a shift member (not shown) of the travel transmission is operated by outputting the transmission actuator 51 from the control device 31. Thus, it is configured such that the number of shift stages of the travel transmission can be changed electrically.

  As shown in FIGS. 3 and 4, the power transmission system to the front wheels 3 of the tractor is equipped with a front wheel transmission 60, and the four-wheel drive that rotates the front wheels 3 at a peripheral speed equal to the peripheral speed of the rear wheels 4. The position can be switched to a speed increasing position where the front wheel 3 is rotated at a higher speed than the peripheral speed of the rear wheel 4. A front wheel transmission actuator 52 is linked to the front wheel transmission device 60, and the front wheel transmission device 60 is operated by operating the shift member 61 of the front wheel transmission device 60 by outputting to the front wheel transmission actuator 52 from the control device 31. By switching to the four-wheel drive position or the acceleration position, the rotational speed of the front wheel 3 can be changed.

  The rear wheels 4 and 4 are equipped with right and left side brakes 62 and 62, and right and left side brake pedals 62a and 62a are linked to the right and left side brakes 62 and 62, respectively. Brake cylinders 53 and 53 are linked to the right and left side brake pedals 62a and 62a. By outputting from the control device 31 to the operation valves 54 and 54 connected to the brake cylinders 53 and 53, the right and left side brake pedals 62a and 62a Alternatively, the left side brakes 62, 62 can be electrically operated to the braking side.

  As shown in FIG. 3, the PTO actuator 55 is linked to the PTO shaft 11 provided at the rear portion of the transmission case 7, and is linked to the PTO shaft 11 by outputting from the control device 31 to the PTO actuator 55. It is possible to drive and stop the rotary F1 of the tillage device F that has been made. In this tractor, when the control device 31 outputs to the PTO actuator 55 based on the detection result of the lift position detection sensor 41 and it is determined that the tilling device F has been raised to the raised position, the rotary F1 is automatically turned on. When the tiller F is lowered from the raised position, the rotary F1 is automatically driven.

  The differential lock actuator 56 is linked to a differential lock device 64 of the rear wheel differential 63 of the tractor. By outputting the differential lock actuator 56 from the control device 31, the differential lock device 64 is operated to lock the rear wheel differential 63, and the right and left The rear wheels 4 and 4 can be rotated with substantially no difference in rotational speed.

  A display device 57 (buzzer and lamp) is provided in the front part of the driver's seat 5, and by outputting to the display device 57 from the control device 31, the buzzer is sounded or the lamp is turned on so that the driver can be lit. Visual or auditory information can be provided.

  The above-described detection devices and output devices are connected to the control device 31, and output devices such as the motor drive circuit 45, the electromagnetic valve 46, and the electronic governor controller 48 from the control device 31 based on the detection results from the detection devices. Automatic output control and automatic turning control, which will be described later, can be realized by performing output in a similar manner.

[Automatic linear control and automatic turning control]
Based on FIG. 5 to FIG. 8, the automatic straight-ahead control and the automatic turning control (corresponding to the automatic turning control means) implemented in this tractor will be described. FIG. 5 shows a main routine of the control device 31, and FIG. 6 shows a subroutine when the automatic straight-ahead control is performed. 7 and 8 show a subroutine when automatic turning control is performed.

  As shown in FIG. 5, data detected by the detection devices shown in FIG. 3 and input to the control device 31 is monitored (step # 11). If it is determined that the rectilinear lever 35 has been operated to the rectilinear position based on the detection result of the lever position detection sensor 36 (YES in step # 12), automatic rectilinear control described later is performed (step # 13). .

  On the other hand, when it is determined that the turning lever 37 is operated in the left direction L or the right direction R based on the detection result of the turning direction detection sensor 38 (step # 14, YES), automatic turning control described later is performed. (Step # 15). When the turning lever 37 is operated in the left direction L or the right direction R after the rectilinear lever 35 is operated to the rectilinear position, automatic rectilinear control and automatic turning control described later are temporarily overlapped. The

  As shown in FIG. 6, when the rectilinear lever 35 is operated to the rectilinear position and the automatic rectilinear control is performed, the lift cylinder is output so that the tiller F is lowered to the lowered position by being output from the controller 31 to the electromagnetic valve 46. 9 is shortened (step # 21), and is output from the control device 31 to the differential lock actuator 56 and the rear wheel differential 63 is locked, and the left and right rear wheels 4 and 4 are rotated with substantially no difference in rotational speed. Thus, the straightness of the tractor is improved (step # 22). Although not shown, when the tilling device F descends from the raised position, the control device 31 outputs the power to the PTO actuator 55, and the rotary F1 of the tilling device F is automatically rotated.

  Next, while the vehicle speed detected by the vehicle speed sensor 67 is fed back, the control device 31 outputs to the electronic governor controller 48 and the speed change actuator 51, so that the rotational speed of the engine 2 is set to a preset vehicle speed when traveling straight ahead. Is electrically controlled, and the traveling transmission is electrically shifted to a preset number of gears for straight travel, and is automatically shifted to the vehicle speed for straight travel (step # 23). In this way, by automatically changing the vehicle speed when going straight ahead, the driver does not have to depress the accelerator pedal (not shown), improving the workability of the straight running work and improving the accuracy. The tractor can often travel straight ahead.

  The rotational speed of the engine 2 and the shift speed of the traveling transmission can be changed and adjusted by a straight speed adjustment tool (not shown) and a straight gear speed adjustment tool (not shown) installed near the driver seat 5. The driver can operate the straight rotation speed adjustment tool or the straight shift speed adjustment tool to change or adjust the straight rotation speed or the shift speed (vehicle speed) according to conditions such as the field. In addition, instead of the rectilinear rotation speed adjusting tool and the rectilinear shift speed adjusting tool, a straight traveling vehicle speed adjusting tool (not shown) provided near the driver's seat 5 may be configured to change and adjust the vehicle speed during straight traveling.

  Next, based on the detection result of the steering angle sensor 32, it is determined whether or not the driver is operating the steering handle 6 (step # 24), and the steering operation amount of the driver's steering handle 6 is preset. When it is less than the set operation amount and it is determined that the driver holds the steering wheel 6 and does not steer in either the right or left direction (when the driver is going to drive the tractor straight) (Step # 24, NO), based on the detection results of the direction sensor 39 and the yaw rate sensor 40, it is determined whether or not the traveling direction of the traveling vehicle body 1 deviates from the set direction (Step # 25). For example, when the tractor is moved to the point A0 in FIG. 11 and the rectilinear lever 35 is operated to the rectilinear position, A0 and B1 in FIG. The direction of the connecting straight line is set as the setting direction.

  When it is determined that the yaw rate detected by the yaw rate sensor 40 changes with respect to the set direction set based on the detection result from the direction sensor 39 and the traveling direction of the traveling vehicle body 1 deviates from the set direction (step # 25). -YES), the controller 31 outputs to the motor drive circuit 45 to drive the steering motor 30 so that the front wheel 3 is steered in the direction opposite to the direction in which the yaw rate has changed from the set direction. The tractor is automatically steered so as to move along a preset setting direction (step # 26).

  Although not shown, the motor drive circuit 45 sends the steering motor 30 to the steering motor 30 so that the steering motor 30 rotates at a predetermined rotational speed by feeding back the rotational speed of the drive shaft 30a detected by the drive shaft rotation sensor 33. It is configured to be output. Note that the steering motor 30 may be configured to rotate at a rotational speed proportional to the amount of change in the yaw rate detected by the yaw rate sensor 40. The steering motor gradually increases as the amount of change in the yaw rate detected by the yaw rate sensor 40 increases. You may comprise so that the rotation speed of 30 may be increased.

  When it is determined that the traveling direction of the traveling vehicle body 1 has been corrected in the preset setting direction based on the detection result of the yaw rate sensor 40 (step # 27, YES), the motor drive circuit 45 from the control device 31. And the steering motor 30 is stopped (step # 28).

  When the state in which it is determined that the driver holds the steering handle 6 and does not steer the steering handle 6 in either the right or left direction is continued, the above-described forward / reverse rotation and stop of the steering motor 30 are performed. While repeating (Steps # 24 to # 28) (# 29, NO), the traveling direction of the tractor is corrected, and the tractor is caused to travel along a preset setting direction.

  If it is determined that the driver steers the steering handle 6 to the right or left (YES in step # 24), the driver's intention to operate the steering handle 6 is given priority, and the steering motor 30 is not forward and reverse, the automatic straight-ahead control is terminated, and the front wheel 3 is steered according to the driver's operation of the steering handle 6.

  As described above, the steering motor 12 is automatically operated by reversing the steering motor 30 constituting the steering differential mechanism 20 to automatically steer the traveling vehicle body 1 along a preset setting direction. Is configured to do.

  It should be noted that the automatic linear control is automatically terminated when the automatic linear control is canceled by the automatic turning control described later while the automatic linear control is being performed (step # 29, YES). .

  As shown in FIGS. 7 and 8, when the turning lever 37 is operated in the left direction L or the right direction R and automatic turning control is performed, the control device 31 outputs the electromagnetic valve 46 and the tilling device F is in the middle. The lift cylinder 9 is extended so as to rise to the position at a low speed (step # 31). The speed at which the tilling device F rises is set to a first ascent speed V1 set in advance by the driver by dialing the ascent speed adjusting tool 43, and the tilling device F is moved from the intermediate position described later to the ascending position. Is set to a speed slower than the second ascending speed V2, and the tilling device F is configured to slowly rise from the field (see FIG. 9B).

  By slowly raising the cultivator F from the field, the soil cultivated when the cultivator F is raised at a low speed is piled up on the tillage trace of the cultivator F formed at the lowered position. The tillage mark formed at the position can be reduced. Further, by configuring the first ascending speed V1 to be adjustable by the ascending speed adjusting tool 43, for example, depending on the hardness of the field, the depth of cultivating the field, the type of the tillage device F attached to the tractor, etc. 1 Ascending speed V1 can be changed and adjusted, and a tilling operation or the like can be performed at a suitable ascent speed of the tilling device F.

  The raised position is set to the position where the tilling device F is most raised, and the lowered position is the position of the tilling device F set by the driver in advance by a tilling depth adjuster (not shown) provided on the driver seat 5. It is set to the position where it enters the ground (depth of plowing the field). The intermediate position is set to a height set in advance by the driver by dialing the intermediate position adjuster 44 (for example, in this embodiment, the lower end of the rotary F1 of the tillage device F is substantially the same as the farm scene). (Height) is set (see FIG. 9B).

  Next, based on the detection result of the lift position detection sensor 41, it is determined whether the tilling device F has been raised to the intermediate position (step # 32), and when it is determined that the tilling device F has been raised to the intermediate position ( (Step # 32, YES), the above-mentioned automatic straight-ahead control is canceled (step # 33, step # 29, YES). Thus, even if the turning lever 37 is operated, the tractor turns with the rotary F1 of the tilling device F entering the field by continuing the automatic linear advance control until the tilling device F rises to the intermediate position. This can prevent the rotary F1 of the tillage device F from roughing the field.

  When it is determined that the tillage device F has been raised to the intermediate position, the lift cylinder 9 is extended so that the control device 31 outputs the electromagnetic valve 46 to the solenoid valve 46 so that the tilling device F rises to the raising position at a high speed (step # 34). ). The second ascending speed V2 for raising the tillage device F from the intermediate position to the ascending position is set to a speed faster than the first ascent speed V1 described above, and the tilling device F that has risen from the field can be raised to the ascending position faster. It is possible to improve the workability of the turning operation of the tractor. Although not shown, when the tillage device F rises to the raised position, the output from the control device 31 to the PTO actuator 55 is cut off, and the rotary F1 of the tillage device F automatically stops.

  Next, while the vehicle speed detected by the vehicle speed sensor 67 is fed back, the control device 31 outputs to the electronic governor controller 48 and the speed change actuator 51, so that the rotational speed of the engine 2 is set to a preset vehicle speed at the time of turning. Is electrically controlled, and the travel transmission is electrically shifted to a preset number of gears at the time of turning to automatically shift to the vehicle speed at the time of turning (step # 35).

  Specifically, for example, when the straight rotation speed adjusting tool and the straight shift speed adjusting tool (or the straight vehicle speed adjusting tool) are set so that the vehicle travels straight ahead at a higher speed than when turning, the rotational speed of the engine 2 is reduced to a low speed. Thus, the shift operation is performed so that the number of shift stages of the traveling transmission is low. Further, for example, when the straight rotation speed adjuster and the straight shift speed adjustment tool (or straight vehicle speed adjuster) are set so that the vehicle travels straight at a lower speed than when turning, the rotation speed of the engine 2 is controlled to be high. The speed change operation is performed so that the number of shift stages of the travel transmission is high. Thus, by automatically changing the vehicle speed at the time of turning, the driver does not have to depress the accelerator pedal (not shown), and the workability of turning work can be improved and the accuracy can be improved. You can turn the tractor well.

  The number of revolutions of the engine 2 during turning and the number of gears of the traveling transmission can be changed and adjusted by a turning speed adjusting tool (not shown) or a turning gear number adjusting tool (not shown) installed near the driver's seat 5. By configuring the turning speed adjusting tool or the turning gear speed adjusting tool, the driver can change and adjust the turning speed or the gear speed (vehicle speed) according to conditions such as the field. Instead of the turning speed adjusting tool and the turning gear speed adjusting tool, a turning vehicle speed adjusting tool (not shown) installed near the driver's seat 5 may be configured to change and adjust the vehicle speed during turning.

  Next, it is output from the control device 31 to the differential lock actuator 56, and the lock of the rear wheel differential 63 operated by the automatic linear advance control is released (step # 36).

  Next, the steering differential mechanism is output from the control device 31 to the motor drive circuit 45 so that the tractor turns left or right in the direction in which the driver operates the turning lever 37 leftward L or rightward R. The 20 steering motors 30 are turned (step # 37).

  Next, an output is made from the control device 31 to the front wheel transmission actuator 52, the front wheel transmission device 60 is switched to the acceleration position (step # 38), and the rotational speed of the front wheel 3 is shifted to the high speed side to increase the speed ( Step # 39), the control device 31 outputs the operation valve 54, operates the brake cylinder 53, operates the side brake 62 on the turning center side to the braking side, and turns the tractor in a small turn. Specifically, for example, when the driver operates the turning lever 37 in the left direction, the brake cylinder 53 linked to the left side brake 62 in which the tractor turns left is operated, and the left rear wheel 4 is operated. Apply braking force.

  The control device 31 is configured so that the series of control of Steps # 33 to # 39 after it is determined that the tillage device F has been raised to the intermediate position is configured to be executed substantially simultaneously, and the tractor can be quickly turned. It is configured to be changeable.

  Next, based on the detection result of the front wheel break angle sensor 66, it is determined whether the front wheel 3 has been operated to a preset front wheel steering angle (step # 40), and the steering motor 30 is driven to turn the tractor. When the front wheel 3 is operated at the front wheel steering angle corresponding to the preset turning radius to be made (step # 40, YES), the output from the control device 31 to the motor drive circuit 45 is cut off, and the steering is performed. The turning drive of the motor 30 is stopped, and the state in which the front wheel 3 is operated at a predetermined front wheel steering angle is maintained (step # 41).

  Next, based on the detection results of the azimuth sensor 39 and the yaw rate sensor 40, the tractor is turned with the steering handle 6 being operated at a predetermined front wheel steering angle, and the tractor is set in advance slightly before the turning angle. It is determined whether the vehicle has turned to an intermediate angle (step # 42). If it is determined that the tractor has turned to an intermediate angle (step # 42, YES), an output is output from the control device 31 to the motor drive circuit 45, and the front wheel 3 is directed straight (in the direction of the white arrow in FIG. 10). In this way, the steering motor 30 is driven straight (step # 43).

  In this way, when the tractor turns to an intermediate angle, the front wheel 3 is configured to turn straight, for example, when the tractor is turned to the turning angle and then the front wheel 3 is turned to the straight direction. In comparison, the front wheel 3 can be operated in the straight direction without difficulty. When the turning angle is changed by the turning angle adjuster 42, the intermediate angle is configured to be changed along with the change of the turning angle. An intermediate angle adjuster (not shown) capable of changing the intermediate angle may be provided near the driver's seat 5 so that the intermediate angle with respect to the turning angle can be changed larger or smaller.

  Next, based on the detection results of the azimuth sensor 39 and the yaw rate sensor 40, it is determined whether or not the tractor has turned to a preset turning angle by the turning angle adjuster 42 (step # 44), and the front wheel break angle sensor 66 is determined. Based on the detection result, it is determined whether or not the front wheel 3 has been operated so as to be directed straight ahead (step # 45). When it is determined that the tractor turns to the turning angle and the front wheels 3 are directed straight (step # 44 • YES, step # 45 • YES), the output from the control device 31 to the motor drive circuit 45 is cut off. Then, the steering motor 30 is stopped to release the straight drive of the steering motor 30 (step # 46).

  As described above, the front wheel automatic operation means is configured to automatically operate the front wheel 3 in the straight traveling direction side of the traveling vehicle body 1 at the end of the automatic turning of the traveling vehicle body 1 by the automatic turning control.

  When the turn of the tractor is completed, the control device 31 outputs to the display device 57 to sound a buzzer or turn on the lamp to notify the driver that the turn of the tractor has been completed visually or audibly ( Step # 47), canceling the automatic speed change of the engine 2 and the speed of the travel transmission, and according to the driver's operation of the accelerator pedal and the speed changer (not shown), the speed of the engine 2 and the travel speed change Automatically shifts to the vehicle speed at the time of work in which the number of gears is changed (step # 48), and the automatic turning control is terminated.

  When the automatic turning control is completed, the driver performs the adjacent plowing between the adjacent adjacent plows, and operates the straight advance lever 35 to the straight advance position again, whereby the automatic straight control is performed. From then on, it is possible to continuously cultivate the field by repeatedly performing automatic straight-ahead control, automatic turning control, and adjacent plowing by the driver.

[Tractor turning status]
Based on FIG. 9, FIG. 10, FIG. 12, and FIG. 13, the turning state of the tractor when the above-described automatic straight-ahead control and automatic turning control are performed will be described. FIG. 9 is a schematic view for illustrating a situation in which the tilling device F rises after the driver operates the turning lever 37. FIGS. 9 (a) and 9 (b) are a schematic plan view and a schematic side view. Respectively. FIG. 10 is a schematic diagram for explaining a situation in which the tractor turns, and an outline when the turning angle adjusting tool 42 is set to 200 degrees (FIG. 10 (A)) or 180 degrees (FIG. 10 (B)). Each plan view is shown.

  FIGS. 12 and 13 are schematic views for explaining the turning situation of the conventional tractor, and correspond to FIGS. 9 and 10, respectively. FIG. 13 (a) is a schematic diagram assuming a case where the conventional tractor is turned by 200 degrees, and does not indicate that the turning angle can be adjusted by the conventional tractor.

  As shown in FIGS. 9 (a) and 9 (b), after the driver operates the turning lever 37, the tilling device F rises to the intermediate position at the first rising speed V1 until the rotary F1 comes out completely from the field scene. During the period (during L1 in FIG. 9), the automatic straight-ahead control is continued and the tractor does not turn. As a result, like the conventional tractor shown in FIGS. 12 (a) and 12 (b), the tiller F is raised almost simultaneously with the driver operating the turning lever 37, and the rotary F1 of the tiller F is removed from the field. The tractor does not turn in a state where it has not come out, and it is less likely to roughen the field by raising the tractor's tillage device F, and it is difficult for excessive force to act on the tiller device F. Breakage of the tillage device F can be prevented.

  Specifically, as shown in FIG. 9 (a) and FIG. 12 (a), the farming that has entered the ground by turning the tractor while the rotary F1 of the tillage device F has not come out of the farm field. It is possible to prevent the device F from moving laterally with the turning of the tractor and forming tilling marks on the field by the lateral movement of the tilling device F. In addition, the tractor turns without the rotary F1 of the tilling device F coming out of the field, and an excessive force in the lateral direction acts on the tilling device F, so that the tilling device F can be prevented from being damaged.

  Further, as shown in FIGS. 9 (b) and 12 (b), the tilling device F is slowly raised at a low speed at the first rising speed V1 until the rotary F1 comes out of the field, so that at the lowered position. The soil cultivated when raising the tillage device F at a low speed is piled on the tillage trace of the formed tillage device F, and the tillage trail formed at the lowered position can be reduced. By raising at a high speed like a tractor, it is possible to prevent the formation of tillage marks of the rotary F1 recessed in a semicircular column shape that is long to the left and right in the field when viewed from the side. Note that when the tiller F rises to the intermediate position at the first ascent speed V1, the tiller F rises at the second ascent speed V2 at a high speed from the intermediate position to the ascending position (between L2 in FIG. 9). .

  As shown in FIGS. 10 (a) and 10 (b), when the driver travels to the B1 point by continuing the automatic straight-ahead control for a distance L1 from the A1 point at which the turning lever 37 is operated so as to turn to the right. The tractor automatically turns by automatic turning control. When the tractor turns at a predetermined turning radius (front wheel steering angle of the front wheel 3) and turns to an intermediate angle slightly before the turning angle (200 degrees or 180 degrees) set by the turning angle adjuster 42, the left and right front wheels 3 and 3 are steered in the direction opposite to the direction in which the tractor is turning, and when turning to the turning angle, the left and right front wheels 3 and 3 move in the straight direction of the self-propelled vehicle body 1 (the white arrow in FIG. 10). The automatic turning control is finished by automatically being operated in a state in which it is directed in the same direction as the direction of

  As a result, as in the conventional tractor shown in FIGS. 13 (a) and 13 (b), the left and right front wheels 3 and 3 are automatically operated in the same direction as the tractor is turning. It is not necessary to operate the steering handle 6 in the direction opposite to the direction of turning of the tractor after the turning control is finished and the automatic turning control is finished, and the workability of the adjacent tilling work after turning can be improved. it can.

  Further, as shown in FIGS. 10 (a) and 10 (b), when the width of the tillage device F is different, the turning angle is changed and adjusted by the turning angle adjuster 42, for example, as shown in FIG. 10 (a). In the case where the width of the tillage device F is relatively narrow and the adjacent tillage is relatively close, the turning angle is set to a large value (200 degrees in the example of FIG. 10 (a)), and the tractor is turned many times. ), When the width of the tillage device F is relatively wide and the adjacent tillage is relatively far away, the turning angle is set to a small value (180 degrees in the example of FIG. 10 (b)), and the tractor is turned to reduce the tractor. Can be positioned near the adjacent tillage, and the workability of the turning work can be improved.

[Status of tractor tillage work]
Based on FIG. 11, the state of tilling work of the tractor when the above-described automatic linear advance control and automatic turning control are performed will be described. FIG. 11 is a schematic plan view for explaining a situation where the tractor goes straight and turns. As shown in FIG. 11, when the tractor is moved to the point A0 and the rectilinear lever 35 is operated to the rectilinear position, the front wheel 3 is automatically steered only by the driver continuing to hold the steering 6 by the automatic rectilinear control. Thus, the tractor can automatically go straight to the A1 point.

  When the turning lever 37 is operated at the A1 point, the tillage device F starts to rise, and the automatic linear control is continued from the A1 point to the B1 point for a distance L1. Then, the front wheel 3 is automatically steered only by the driver continuing to hold the steering 6 by the automatic turning control, and the tractor can be automatically turned to the point C1.

  When the tractor moves to point C1 and finishes turning, the automatic turning control is finished with the front wheels 3 facing in the same direction as the straight traveling direction of the self-propelled vehicle body 1, and the rotational speed of the engine 2 and the number of shift stages of the traveling transmission are determined. As a result, the driver can operate the accelerator pedal and the shift operation tool.

  When the driver operates the tractor from the C1 point to perform adjacent plowing on the adjacent adjacent plow, moves the tractor to the D1 point and operates the rectilinear lever 35 to the rectilinear position again, the automatic rectilinear control is performed again, The tractor can travel straight in the direction in which the driver performs adjacent plowing. Thereafter, the field can be continuously cultivated by repeating the automatic straight traveling, automatic turning and adjacent plowing.

  As described above, by configuring the tractor so as to perform automatic straight advance and automatic turn, the driver simply sits on the driver seat 5 and operates the straight advance lever 35 to hold the steering handle 6. Plowing work can be performed while automatically moving 1 straight, and the traveling vehicle body 1 can be automatically turned simply by operating the turning lever 37 and holding the steering handle 6. As a result, the operation of the steering handle 6 for moving the traveling vehicle body 1 straight and the operation of the steering handle 6 for rotating the traveling vehicle body 1 become unnecessary, and attention is paid to the operation of the steering handle 6 for moving the traveling vehicle body 1 straight and turning. The traveling vehicle body 1 can be easily moved straight and turned, and the tilling operation can be performed efficiently while satisfactorily checking the state of the field by sitting on the driver's seat 5.

[First Alternative Embodiment of the Invention]
In the above-mentioned [Best Mode for Carrying Out the Invention], when it is determined that the turning lever 37 is operated in the left direction L or the right direction R, based on the detection results of the azimuth sensor 39 and the yaw rate sensor 40, In the example, the automatic turning control means is configured such that the front wheel 3 is steered in the left direction L or the right direction R where the turning lever 37 is operated, and the traveling vehicle body 1 turns at a predetermined turning angle. Based on the detection result of either the azimuth sensor 39 or the yaw rate sensor 40, the front wheel 3 is steered in the left direction L or right direction R where the swivel lever 37 is manipulated, and the traveling vehicle body is set at a preset turning angle. The automatic turning control means may be configured so that 1 turns. Also, the tractor is equipped with a GPS receiver (not shown) and a navigation system (not shown), and the turning lever 37 is operated based on the current position of the tractor and the map information of the navigation system received by the GPS receiver. The automatic turning control means may be configured such that the front wheel 3 is steered in the left direction L or the right direction R and the traveling vehicle body 1 turns at a preset turning angle.

  In the above-mentioned [Best Mode for Carrying Out the Invention], the example in which the turning lever 37 is employed as the turning command input unit has been shown. However, the turning command input unit for inputting the right or left turning command to the traveling vehicle body 1. For example, a different operation tool such as a switch (not shown) may be employed, and a right or left turning command may be input to the traveling vehicle body 1 by a touch panel type screen operation or the like. It may be configured.

  In the above-mentioned [Best Mode for Carrying Out the Invention], the example in which the turning angle adjuster 42 can be changed and adjusted by a dial operation is shown. However, a different turning angle adjuster 42 is adopted. For example, the turning angle adjuster 42 may be configured by an operation switch (not shown) or an operation button (not shown) that can be switched to a plurality of operation positions.

[Second Embodiment of the Invention]
In the above-mentioned [Best Mode for Carrying Out the Invention], an example in which the front wheel automatic operation means is configured so that the left and right front wheels 3 are steered in the same direction as the straight traveling direction of the self-propelled vehicle body 1 is shown. However, the left and right front wheels 3 are not limited to the case where the left and right front wheels 3 are steered in the same direction as the straight traveling direction of the self-propelled vehicle body 1. The front wheel automatic operation means may be configured such that the left and right front wheels 3 exceed the rectilinear direction of the self-propelled vehicle body 1 so that the traveling vehicle body 1 travels straight by automatic rectilinear control. The front wheel automatic operation means may be configured to be steered.

  In the above-mentioned [Best Mode for Carrying Out the Invention], an intermediate angle smaller than the turning angle is set, and when the tractor turns to the intermediate angle, the front wheel 3 is steered to the straight traveling direction side of the self-propelled vehicle body 1. Thus, although the example which comprised the front wheel automatic operation means was shown, the timing which steers the front wheel 3 to the straight-advancing direction side of the self-propelled vehicle body 1 may be a different timing, for example, the tractor turns at a turning angle. At the same time, the front wheel automatic operation means may be configured so that the front wheel 3 is steered to the straight traveling direction side of the self-propelled vehicle body 1, and the front wheel 3 is automatically delayed after the tractor turns to the turning angle. The front wheel automatic operation means may be configured to steer the traveling vehicle body 1 to the straight traveling direction side.

[Third Another Embodiment of the Invention]
In the above-mentioned [Best Mode for Carrying Out the Invention], [First Alternative Embodiment of the Invention] and [Second Alternative Embodiment of the Invention], a tractor provided with a tillage device F as an example of a work vehicle. Although the example in which the automatic linear control and the automatic turning control are applied to the above is shown, it can be similarly applied to different work vehicles equipped with different work devices.For example, by applying to a rice transplanter equipped with a seedling planting device, it can be accurately applied. It is possible to improve the workability of the seedling planting work by running straight, and to improve the workability of the turning work at the edge by turning accurately. Further, the present invention is not limited to the rear wheel 4 and can be similarly applied to, for example, a work vehicle in which a crawler traveling device (not shown) is mounted on the rear axle.

Overall left side view of the tractor Schematic showing structure of steering device and steering differential mechanism Block diagram of control device Schematic diagram of tractor traveling transmission system Flow chart of main routine of control device Flow chart of automatic linear control Flow chart of automatic turning control Flow chart of automatic turning control Schematic for explaining the situation where the tillage device rises Schematic for explaining the situation where the tractor turns Schematic plan view for explaining the situation where the tractor goes straight and turns Schematic for explaining a situation in which a conventional tractor tillage device rises Schematic for explaining the situation where a conventional tractor turns

Explanation of symbols

1 traveling vehicle body 3 front wheel 37 turning lever (turning command input section)
39 Direction sensor
40 Yaw rate sensor (direction sensor)
42 Turning angle adjuster (turn target angle adjuster)

Claims (2)

A direction sensor for detecting the direction of the traveling vehicle body, a turning command input unit for inputting a right or left turning command to the traveling vehicle body,
When a turning command is input by the turning command input unit, the steering wheel is steered to the right or left input by the turning command input unit based on the detection result of the direction sensor, and a preset automatic operation is performed. Automatic turning control means for automatically turning the traveling vehicle body to a turning target angle that is an angle at which the work vehicle turns between the start of turning and the end of automatic turning;
A work vehicle comprising a turning target angle adjuster capable of changing and adjusting the turning target angle in the automatic turning control by the automatic turning control means .   2. The work according to claim 1, further comprising a front wheel automatic operation means for automatically operating the front wheel in the straight direction direction side of the traveling vehicle body or in the reverse direction side beyond the straight traveling direction at the end of the automatic turning of the traveling vehicle body by the automatic turning control means. car.

Images